2 ## This file is processed by Perl scripts to produce an ASCII and an HTML
3 ## version. Lines starting with ## are omitted. The markup used with paragraphs
6 ## Markup User for HTML Text
7 ## ------------------------------------------------------
8 ## \...\ option fixed-pitch "quoted"
9 ## \$...$\ variable $italic $plain
10 ## \*...*\ titles, quotes italic "quoted"
11 ## \(...)\ file name italic plain
12 ## \[...]\ replaceable <italic> <plain>
13 ## \?...?\ URL URL plain
14 ## \^...^\ Unix command italic plain
15 ## \%...%\ Exim driver bold "quoted"
16 ## \^^.^^\ C function bold plain
17 ## ::...:: header name italic: plain:
18 ## //...// domain italic plain
19 ## \/.../\ local part italic plain
20 ## \"..."\ literal fixed-pitch "quoted"
21 ## \\...\\ SMTP, build small caps caps
22 ## \**...**\ warn, item bold plain
23 ## \-...-\ cmd option -italic -plain
24 ## \# hard space space
26 ## ``...'' quoted string “...” "..."
28 ## @\ is used when a real backslash is required
30 ## In addition, sequences of not blank lines that start with ==> are displayed
31 ## in fixed-pitch with no further interpretation. A line containing only [[br]]
32 ## is removed from the text version, but turned into <br> in the HTML version.
34 ## The starts of sections and of questions and answers are automatically
35 ## detected by the scripts.
41 This is the FAQ for the Exim Mail Transfer Agent. Many thanks to the many
42 people who provided the original information. This file would be amazingly
43 cluttered if I tried to list them all. Suggestions for corrections,
44 improvements, and additions are always welcome.
46 This version of the FAQ applies to Exim 4.43 and later releases.
48 References of the form Cnnn, Fnnn, Lnnn, and Snnn are to the sample
49 configuration, filter, \^^local_scan()^^\, and ``useful script'' files. These
50 are hyperlinked from the HTML version of this FAQ. They can also be found in
51 the separately distributed directory called \(config.samples)\. The primary
54 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4/config.samples.tar.gz?\
55 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4/config.samples.tar.bz2?\
57 There are brief descriptions of these files at the end of this document.
60 Last update: 14-October-2004
63 The FAQ is divided into the following sections:
66 1. Building and Installing
68 3. Routing to remote hosts
69 4. Routing for local delivery
73 8. Rewriting addresses
81 16. Modifying message bodies
82 17. Encryption (TLS/SSL)
92 98. Configuration cookbook
93 99. List of sample configurations
99 Q0001: Exim is crashing. What is wrong?
101 A0001: Exim should never crash. The author is always keen to know about
102 crashes, so that they can be diagnosed and fixed. However, before you
103 start sending me email, please check that you are running the latest
104 release of Exim, in case the problem has already been fixed. The
105 techniques described below can also be useful in trying to pin down
106 exactly which circumstances caused the crash and what Exim was trying to
107 do at the time. If the crash is reproducible (by a particular message,
108 say) keep a copy of that message.
111 Q0002: Exim is not working. What is wrong? How can I check what it is doing?
113 A0002: Exactly how is it not working? Check the more specific questions in the
114 other sections of this FAQ. Some general techniques for debugging are:
116 (1) Look for information in Exim's log files. These are in the \(log)\
117 directory in Exim's spool directory, unless you have configured a
118 different path for them. Serious operational problems are reported
121 (2) If the problem involves the delivery of one or more messages, try
122 forcing a delivery with the \-M-\ option and also set the \-d-\
123 option, to cause Exim to output debugging information. For example:
125 ==> exim -d -M 0z6CXU-0005RR-00
127 The output is written to the standard error stream. You need to have
128 admin privileges to use \-M-\ and \-d-\.
130 (3) If the problem involves incoming SMTP mail, try using the \-bh-\
131 option to simulate an incoming connection from a specific host,
134 ==> exim -bh 10.9.8.7
136 This goes through the motions of an SMTP session, without actually
137 accepting a message. Information about various policy checks is
138 output. You will need to know how to pretend to be an SMTP client.
140 (4) If the problem involves lack of recognition or incorrect handling
141 of local addresses, try using the \-bt-\ option with debugging turned
142 on, to see how Exim is handling the address. For example,
144 ==> exim -d -bt z6abc
146 shows you how it would handle the local part \"z6abc"\.
149 Q0003: What does the error \*Child process of address_pipe transport returned
150 127 from command xxx*\ mean?
152 A0003: It means that when a transport called \%address_pipe%\ was run to pass an
153 email message by means of a pipe to another process running the command
154 xxx, the return code from that command was 127, which indicates some kind
155 of error (the success return code is 0).
157 The most common meaning of exit code 127 is that when Exim tried to run
158 the command \(xxx)\, it failed. One cause of this might be incorrect
159 permissions on the file containing the command. See also Q0026.
162 Q0004: My virtual domain setup isn't working. How can I debug it?
164 A0004: You can use an exim command with \-d-\ to get it to show you how it is
165 processing addresses. You don't actually need to send a message; use the
166 \-bt-\ option like this:
168 ==> exim -d -bt localpart@virtualhost
170 This will show you which routers it is using. If the problem appears
171 to be with the expansion of an option setting, you can use the
172 \debug_print\ option on a router to get Exim to output the expanded
173 string values as it goes along.
176 Q0005: Why is Exim not rejecting incoming messages addressed to non-existent
179 A0005: This is controlled by the ACL that is run for each incoming RCPT
180 command. It is defined by the \acl_smtp_rcpt\ option. You can check this
181 part of your configuration by using the \-bh-\ option to run a simulated
182 SMTP session, during which Exim will tell you what things it is
186 Q0006: I've put an entry for \"*.my.domain"\ in a DBM lookup file, but it isn't
189 A0006: You need to request ``partial matching'' by setting the search type to
190 \partial-dbm\ in order for this to work.
193 Q0007: I've put the entry \"*@domain.com"\ in a lookup database, but it isn't
194 working. The expansion I'm using is:
196 ==> ${lookup{${lc:$sender_address}}dbm{/the/file} ...
198 A0007: As no sender address will ever be //*@domain.com// this will indeed have
199 no effect as it stands. You need to tell Exim that you want it to look
200 for defaults after the normal lookup has failed. In this case, change the
201 search type from \"dbm"\ to \"dbm*@"\. See the section on \*Default values in
202 single-key lookups*\ in the chapter entitled \*File and database
203 lookups*\ in the Exim manual.
206 Q0008: If I run \"./exim -d -bt user@domain"\ all seems well, but when I send
207 a message from my User Agent, it does not arrive at its destination.
209 A0008: Try sending a message directly to Exim by typing this:
211 ==> exim -v user@domain
212 <some message, could be empty>
215 If the message gets delivered to a remote host, but never arrives at its
216 final destination, then the problem is at the remote host. If, however,
217 the message gets through correctly, then the problem may be between your
218 User Agent and Exim. Try setting Exim's \log_selector\ option to include
219 \"+arguments"\, to see with which arguments the UA is calling Exim.
222 Q0009: What does \*no immediate delivery: too many messages received in one SMTP
225 A0009: An SMTP client may send any number of messages down a single SMTP
226 connection to a server. Initially, an Exim server starts up a delivery
227 process as soon as a message is received. However, in order not to start
228 up too many processes when lots of messages are arriving (typically
229 after a period of downtime), it stops doing immediate delivery after a
230 certain number of messages have arrived down the same connection. The
231 threshold is set by \smtp_accept_queue_per_connection\, and the default
232 value is 10. On large systems, the value should be increased. If you are
233 running a dial-in host and expecting to get all your mail down a single
234 SMTP connection, then you can disable the limit altogether by setting
238 Q0010: Exim puts \*for \[address]\*\ in the ::Received:: headers of some, but not all,
239 messages. Is this a bug?
241 A0010: No. It is deliberate. Exim inserts a ``for'' phrase only if the incoming
242 message has precisely one recipient. If there is more than one
243 recipient, nothing is inserted. The reason for this is that not all
244 recipients appear in the ::To:: or ::Cc:: headers, and it is considered a
245 breach of privacy to expose such recipients to the others. A common
246 case is when a message has come from a mailing list.
249 Q0011: Instead of \^exim_dbmbuild^\, I'm using a homegrown program to build DBM
250 (or cdb) files, but Exim doesn't seem to be able to use them.
252 A0011: Exim expects there to be a binary zero value on the end of each key used
253 in a DBM file if you use the \"dbm"\ lookup type, but not for the \"dbmnz"\
254 lookup type or for the keys of a cdb file. Check that you haven't
255 slipped up in this regard.
258 Q0012: Exim is unable to route to any remote domains. It doesn't seen to be
259 able to access the DNS.
261 A0012: Try running \"exim -d+resolver -bt \[remote address]\"\. The \-d-\
262 options turns on debugging output, and the addition of \"+resolver"\
263 will make it show the resolver queries it is building and the results of
264 its DNS queries. If it appears unable to contact any name servers, check
265 the contents and permissions of \(/etc/resolv.conf)\.
268 Q0013: What does the error message \*transport system_aliases: cannot find
269 transport driver "redirect" in line 92*\ mean?
271 A0013: \%redirect%\ is a router, not a transport. You have put a configuration
272 for a router into the transports section of the configuration file.
275 Q0014: Exim is timing out after receiving and responding to the DATA command
276 from one particular host, and yet the client host also claims to be
277 timing out. This seems to affect only certain messages.
279 A0014: This kind of problem can have many different causes.
281 (1) This problem has been seen with a network that was dropping all
282 packets over a certain size, which mean that the first part of the SMTP
283 transaction worked, but when the body of a large message started
284 flowing, the main data bits never got through the network. See also
287 (2) This can also happen if a host has a broken TCP stack and won't
288 reassemble fragmented datagrams.
290 (3) A very few ISDN lines have been seen which failed when certain data
291 patterns were sent through them, and replacing the routers at both end
292 of the link did not fix things. One of them was triggered by more than 4
293 X's in a row in the data.
296 Q0015: What does the message \*Socket bind() to port 25 for address (any)
297 failed: address already in use*\ mean?
299 A0015: You are trying to run an Exim daemon when there is one already running -
300 or maybe some other MTA is running, or perhaps you have an SMTP line in
301 \(/etc/inetd.conf)\ which is causing \(inetd)\ to listen on port 25.
304 Q0016: I've set \"verify = header_syntax"\ in my ACL, but this causes Exim to
305 complain about header lines like \"To: Work: Jim <jims@email>,
306 Home: Bob <bobs@email>"\ which look all right to me. Is this a bug?
308 A0016: No. Header lines such as ::From::, ::To::, etc., which contain addresses, are
309 structured, and have to be in a specific format which is defined in RFC
310 2822. Unquoted colons are not allowed in the ``phrase'' part of an email
311 address (they are OK in other headers such as ::Subject::). The correct
312 form for that header is
314 ==> To: "Work: Jim" <jims@email>, "Home: Bob" <bobs@email>
316 You will sometimes see unquoted colons in ::To:: and ::Cc:: headers, but only
317 in connection with name lists (called ``groups''), for example:
319 ==> To: My friends: X <x@y.x>, Y <y@w.z>;,
320 My enemies: A <a@b.c>, B <b@c.d>;
322 Each list must be terminated by a semicolon, as shown.
325 Q0017: Whenever Exim tries to deliver a specific message to a particular
326 server, it fails, giving the error \*Remote end closed connection after
327 data*\ or \*Broken pipe*\ or a timeout. What's going on?
329 A0017: \*Broken pipe*\ is the error you get on some OS when the remote host just
330 drops the connection. The alternative is \*connection reset by peer*\.
331 There are many potential causes. Here are some of them (see also Q0068):
333 (1) There are some firewalls that fall over on binary zero characters
334 in email. Have a look, e.g. with \"hexdump -c mymail | tail"\ to see if
335 your mail contains any binary zero characters.
337 (2) There are broken SMTP servers around that just drop the connection
338 after the data has been sent if they don't like the message for some
339 reason (e.g. it is too big) instead of sending a 5xx error code. Have
340 you tried sending a small message to the same address?
342 It has been reported that some releases of Novell servers running NIMS
343 are unable to handle lines longer than 1024 characters, and just close
344 the connection. This is an example of this behaviour.
346 (3) If the problem occurs right at the start of the mail, then it could
347 be a network problem with mishandling of large packets. Many emails are
348 small and thus appear to propagate correctly, but big emails will
349 generate big IP datagrams.
351 There have been problems when something in the middle of the network
352 mishandles large packets due to IP tunnelling. In a tunnelled link, your
353 IP datagrams gets wrapped in a larger datagram and sent over a network.
354 This is how virtual private networks (VPNs), and some ISP transit
355 circuits work. Since the datagrams going over the tunnel require a
356 larger packet size, the tunnel needs a bigger maximum transfer unit
357 (MTU) in the network handling the tunnelled packets. However, MTUs
358 are often fixed, so the tunnel will try to fragment the packets.
360 If the systems outside the tunnel are using path MTU discovery, (most
361 Sun Sparc Solaris machines do by default), and set the DF (don't
362 fragment) bit because they don't send packets larger than their \(local)\
363 MTU, then ICMP control messages will be sent by the routers at the
364 ends of the tunnel to tell them to reduce their MTU, since the tunnel
365 can't fragment the data, and has to throw it away. If this mechanism
366 stops working, e.g. a firewall blocks ICMP, then your host never
367 knows it has hit the maximum path MTU, but it has received no ACK on
368 the packet either, so it continues to resend the same packet and the
369 connection stalls, eventually timing out.
371 You can test the link using pings of large packets and see what works:
373 ==> ping -s host 2048
375 Try reducing the MTU on the sending host:
377 ==> ifconfig le0 mtu 1300
379 Alternatively, you can reduce the size of the buffer Exim uses for SMTP
380 output by putting something like
382 ==> DELIVER_OUT_BUFFER_SIZE=512
384 in your \(Local/Makefile)\ and rebuilding Exim (the default is 8192).
385 While this should not in principle have any effect on the size of
386 packets sent, in practice it does seem to have an effect on some OS.
388 You can also try disabling path MTU discovery on the sending host. On
391 ==> echo 1 >/proc/sys/net/ipv4/ip_no_pmtu_disc
393 For a general discussion and information about other operating systems, see
394 \?http://www.netheaven.com/pmtu.html?\. If disabling path MTU discovery
395 fixes the problem, try to find the broken or misconfigured
396 router/firewall that swallows the ICMP-unreachable packets. Increasing
397 timeouts on the receiving host will not work around the problem.
400 Q0018: Why do messages not get delivered down the same connection when I do
401 something like: \"exim -v -R @aol.com"\? For other domains, I do this and
402 I see the appropriate \*waiting for passed connections to get used*\
405 A0018: Recall that Exim does not keep separate queues for each domain, but
406 operates in a distributed fashion. Messages get into its `waiting for
407 host x' hints database only when a delivery has been tried, and has had
408 a temporary error. Here are some possibilities:
410 (1) The messages to \(aol.com)\ got put in your queue, but no previous
411 delivery attempt occured before you did the \-R-\. This might have been
412 because of your settings of \queue_only_load\, \smtp_accept_queue\, or any
413 other option that caused no immediate delivery attempt on arrival. If
414 this is the case, you can try using \-qqR-\ instead of \-R-\.
416 (2) You have set \connection_max_messages\ on the smtp transport, and
417 that limit was reached. This would show as a sequence of messages
418 down one connection, then another sequence down a new connection, etc.
420 (3) Exim tried to pass on the SMTP connection to another message, but
421 that message was in the process of being delivered to \(aol.com)\ by some
422 other process (typically, a normal queue runner). This will break the
423 sequence, though the other delivery should pass its connection on to
424 other messages if there are any.
426 (4) The folk at \(aol.com)\ changed the MX records so the host names have
427 changed - or a new host has been added. I don't know how likely this is.
429 (5) Exim is not performing as it should in this regard, for some reason.
430 Next time you have mail queued up for \(aol.com)\, try running
432 ==> exim_dumpdb /var/spool/exim wait-remote_smtp
434 to see if those messages are listed among those waiting for the relevant
438 Q0019: There seems to be a problem in the string expansion code: it doesn't
439 recognize references to headers such as \"${h_to}"\.
441 A0019: The only valid syntax for header references is (for example) \"$h_to:"\
442 because header names are permitted by RFC 2822 to contain a very wide
443 range of characters. A colon (or white space) is required as the
447 Q0020: Why do connections to my machine's SMTP port take a long time to respond
448 with the banner, when connections to other ports respond instantly? The
449 delay is sometimes as long as 30 seconds.
451 A0020: These kinds of delay are usually caused by some kind of network problem
452 that affects outgoing calls made by Exim at the start of an incoming
453 connection. Configuration options that cause outgoing calls are:
455 (1) \rfc1413_hosts\ and \rfc1413_query_timeout\ (for \*ident*\ calls).
456 Firewalls sometimes block ident connections so that they time out,
457 instead of refusing them immediately. This can cause this problem.
458 See Q5023 for a discussion of the usefulness of \*ident*\.
460 (2) The \host_lookup\ option, the \host_reject_connection\ option, or a
461 condition in the ACL that runs at connection time requires the
462 remote host's name to be looked up from its IP address. Sometimes
463 these DNS lookups time out. You can get this effect with ACL
464 statements like this:
466 ==> deny hosts = *.x.example
468 If at all possible, you should use IP addresses instead of host
469 names in blocking lists in order to avoid this problem.
471 You can use the \-bh-\ option to get more information about what is
472 happening at the start of a connection. However, note that the \-bh-\
473 option does not provide a complete simulation. In particular, no
474 \*ident*\ checks are done, so it won't show up a delay problem that is
475 related to (1) above.
478 Q0021: What does \*failed to create child process to send failure message*\ mean?
479 This is a busy mail server with \smtp_accept_max\ set to 500, but this
480 problem started to occur at about 300 incoming connections.
482 A0021: Some message delivery failed, and when Exim wanted to send a bounce
483 message, it was unable to create a process in which to do so. Probably
484 the limit on the maximum number of simultaneously active processes has
485 been reached. Most OS have some means of increasing this limit, and in
486 some operating systems there is also a limit per uid which can be
490 Q0022: What does \*No transport set by system filter*\ in a log line mean?
492 A0022: Your system filter contains a \"pipe"\ or \"save"\ or \"mail"\ command,
493 but you have not set the corresponding option which specifies which
494 transport is to be used. You need to set whichever of
495 \system_filter_pipe_transport\, \system_filter_file_transport\ or
496 \system_filter_reply_transport\ is relevant.
499 Q0023: Why is Exim refusing to relay, saying \*failed to find host name from IP
500 address*\ when I have the sender's IP address in an ACL condition? My
501 configuration contains this ACL statement:
503 ==> accept hosts = lsearch;/etc/mail/relaydomains:192.168.96.0/24
505 A0023: When checking a host list, the items are tested in left-to-right
506 order. The first item in your list is a lookup on the incoming host's
507 name, so Exim has to determine the name from the incoming IP address in
508 order to perform the test. If it can't find the host name, it can't do
509 the check, so it gives up. You would have discovered what was going
510 on if you had run a test such as
512 ==> exim -bh 192.168.96.131
514 The solution is to put all explicit IP addresses first in the list.
515 Alternatively, you can split the ACL statement into two like this:
517 ==> accept hosts = lsearch;/etc/mail/relaydomains
518 accept hosts = 192.168.96.0/24
520 If the host lookup fails, the first \"accept"\ fails, but then the
521 second one is considered.
524 Q0024: When I run \"exim -bd -q10m"\ I get \*PANIC LOG: exec of exim -q failed*\.
526 A0024: This probably means that Exim doesn't know its own path so it can't
527 re-exec itself to do the first queue run. Check the output of
529 ==> exim -bP exim_path
532 Q0025: I can't seem to get a pipe command to run when I include a \"${if"\
533 expansion in it. This fails:
535 ==> command = perl -T /usr/local/rt/bin/rtmux.pl \
536 rt-mailgate helpdesk \
537 ${if eq {$local_part}{rt} {correspond}{action}}
539 A0025: You need some internal quoting in there. Exim expands each individual
540 argument separately. Because you have (necessarily) got spaces in your
541 \"${if"\ item, you have to quote that argument. Try
543 ==> command = perl -T /usr/local/rt/bin/rtmux.pl \
544 rt-mailgate helpdesk \
545 "${if eq {$local_part}{rt} {correspond}{action}}"
547 \**Warning:**\ If command starts with an item that requires quoting,
548 you cannot just put it in quotes, because a leading quote means that the
549 entire option setting is being quoted. What you have to do is to quote
550 the entire value, and use internally escaped quotes for the ones you
551 really want. For example:
553 ==> command = "\"${if ....}\" arg1 arg2"
555 Any backslashes in the expansion items will have to be doubled to stop
556 them being interpreted by the string reader.
559 Q0026: I'm trying to get Exim to connect an alias to a pipe, but it always
560 gives error code 127, with the comment \*(could mean unable to exec
561 or command does not exist)*\.
563 A0026: If your alias entry looks like this:
565 ==> alias: |"/some/command some parameters"
567 change it to look like this:
569 ==> alias: "|/some/command some parameters"
572 Q0027: What does the error \*Spool file is locked*\ mean?
574 A0027: This is not an error. All it means is that when an Exim delivery
575 process (probably started by a queue runner process) looked at a message
576 in order to start delivering it, it found that another Exim process was
577 already busy delivering it. On a busy system this is quite a common
578 occurrence. If you set \"-skip_delivery"\ in the \log_selector\ option,
579 these messages are omitted from the log.
581 The only time when this message might indicate a problem is if it is
582 repeated for the same message for a very long time. That would suggest
583 that the process that is delivering the message has somehow got stuck.
586 Q0028: Exim is reporting IP addresses as 0.0.0.0 or 255.255.255.255 instead of
587 their correct values. What's going on?
589 A0028: You are using a version of Exim built with gcc on an IRIX box.
593 Q0029: I can't seem to figure out why PAM support doesn't work correctly.
595 A0029: There is a problem using PAM with shadow passwords when the calling
596 program is not running as \/root/\. Exim is normally running as the
597 Exim user when authenticating a remote host.
599 (1) One solution can be found at \?http://www.e-admin.de/pam_exim/?\.
601 (2) PAM 0.72 allows authorization as non-\/root/\, using setuid helper
602 programs. Furthermore, in \(/etc/pam.d/exim)\ you can explicitly
603 specify that this authorization (using setuid helpers) is only
604 permitted for certain users and groups.
606 (3) Another approach is to authenticate using the \^saslauthd^\ daemon,
607 which has its own interface to PAM. The daemon runs as root, so
608 there is no access problem.
610 (4) One suggested solution was to set
612 ==> exim_group=shadow
614 in the configuration file, or the equivalent at build time. This is
615 very strongly discouraged. Do not do it! It works, but it's a
616 potential security exposure. Exim is intended to run as a
617 non-privileged user for much of the time. This setting gives it have
618 privileged access to crucial security information all of the time,
619 simply for the purposes of authentication (which Exim will only
620 spend a tiny part of its total time doing). The result is that a
621 successful compromise of the Exim system can give someone direct
622 access to the system passwords.
625 Q0030: I'm trying to use a query-style lookup for hosts that are allowed to
626 relay, but it is giving really weird errors.
628 A0030: Does your query contain a colon character? Remember that host lists are
629 colon-separated, so you need to double any colons in the query. This
630 applies even if the query is defined as a macro.
633 Q0031: Exim is rejecting connections from hosts that have more than one IP
634 address, for no apparent reason.
636 A0031: You are using Solaris 7 or earlier, and have \"nis dns files"\ in
637 \(/etc/nsswitch.conf)\. Change this to \"dns nis files"\ to avoid hitting Sun
638 bug 1154236 (a bad interaction between NIS and the DNS).
641 Q0032: Exim is failing to find the MySQL library, even though is it present
642 within \\LD_LIBRARY_PATH\\. I'm getting this error:
644 ==> /usr/local/bin/exim: fatal: libmysqlclient.so.6: open failed:
645 No such file or directory
647 A0032: Exim is suid, and \\LD_LIBRARY_PATH\\ is ignored for suid binaries on a
648 Solaris (and other?) systems. What you should be doing is adding
649 \"-R/local/lib/mysql"\ to the same place in the compilation that you added
650 \"-L/local/lib/mysql"\. This tells the binary where to look without
651 needing a path variable.
654 Q0033: What does the error \*lookup of host "xx.xx.xx" failed in yyy router*\
657 A0033: You configured a \%manualroute%\ router to send the message to xx.xx.xx. When
658 it tried to look up the IP address for that host, the lookup failed
659 with a permanent error. As this is a manual routing, this is a
660 considered to be a serious error which the postmaster needs to know
661 about (maybe you have a typo in your file), and there is little point
662 in keeping on trying. So it freezes the message.
664 (1) Don't set up routes to non-existent hosts.
666 (2) If you must set up routes to non-existent hosts, and don't want
667 freezing, set the \host_find_failed\ option on the router to do something
671 Q0034: Exim works fine on one host, but when I copied the binary to another
672 identical host, it stopped working (it could not resolve DNS names).
674 A0034: Is the new host running exactly the same operating system? Most
675 importantly, are the versions of the dynamically loaded libraries
676 (files with names like \(libsocket.so.1)\) the same on both systems? If not,
677 that is probably the cause of the problem. Either arrange for the
678 libraries to be the same, or rebuild Exim from source on the new host.
681 Q0035: I set a \"hosts"\ condition in an ACL to do a lookup in a file of IP
682 addresses, but it doesn't work.
684 A0035: Did you remember to put \"net-"\ at the start of the the search type? If
685 you set something like this:
687 ==> accept hosts = lsearch;/some/file
689 Exim searches the file for the host name, not the IP address. You need
692 ==> accept hosts = net-lsearch;/some/file
694 to make it use the IP address as the key to the lookup.
697 Q0036: Why do I get the error \*Permission denied: creating lock file hitching
698 post*\ when Exim tries to do a local delivery?
700 A0036: Your configuration specifies that local mailboxes are all held in
701 single directory, via configuration lines like these (taken from the
702 default configuration):
706 file = /var/mail/$local_part
708 and the permissions on the directory probably look like this:
710 ==> drwxrwxr-x 3 root mail 512 Jul 9 13:48 /var/mail/
712 Using the default configuration, Exim runs as the local user when doing
713 a local delivery, and it uses a lock file to prevent any other process
714 from updating the mailbox while it is writing to it. With those
715 permissions the delivery process, running as the user, is unable to
716 create a lock file in the \(/var/mail(\ directory. There are two solutions
719 (1) Set the \"write"\ and \"sticky bit"\ permissions on the directory, so
720 that it looks like this:
722 ==> drwxrwxrwt 3 root mail 512 Jul 9 13:48 /var/mail/
724 The \"w"\ allows any user to create new files in the directory, but
725 the \"t"\ bit means that only the creator of a file is able to remove
726 it. This is the same setting as is normally used with the \(/tmp)\
729 (2) Arrange to run the local_delivery transport under a specific group
730 by changing the configuration to read
734 file = /var/mail/${local_part}
737 The delivery process still runs under the user's uid, but with the
738 group set to \"mail"\. The group permission on the directory allows
739 the process to create and remove the lock file.
741 The choice between (1) and (2) is up to the administrator. If the
742 second solution is used, users can empty their mailboxes by updating
743 them, but cannot delete them.
745 If your problem involves mail to \/root/\, see also Q0039.
748 Q0037: I am experiencing mailbox locking problems with Sun's \"mailtool"\ used
751 A0037: See Q9705 in the Sun-specific section below.
754 Q0038: What does the error message \*error in forward file (filtering not
755 enabled): missing or malformed local part*\ mean?
757 A0038: If you are trying to use an Exim filter, you have forgotten to enable
758 the facility, which is disabled by default. In the \%redirect%\ router
759 (in the Exim run time configuration file) you need to set
761 ==> allow_filter = true
763 to allow a \(.forward)\ file to be used as an Exim filter. If you are not
764 trying to use an Exim filter, then you have put a malformed address in
765 the \(.forward)\ file.
768 Q0039: I have installed Exim, but now I can't mail to \/root/\ any more. Why is
771 A0039: Most people set up \/root/\ as an alias for the manager of the host. If
772 you haven't done this, Exim will attempt to deliver to \/root/\ as if it
773 were a normal user. This isn't really a good idea because the delivery
774 process would run as \/root/\. Exim has two trigger guards that stop
775 deliveries running as root. In the build-time configuration, there is a
776 setting called FIXED_NEVER_USERS, which defaults to \"root"\. This
777 setting cannot be overridden. In addition, the default runtime
778 configuration contains the option
780 ==> never_users = root
782 just to be on the safe side. If you really want to run local deliveries
783 as \/root/\, you must use a version of Exim that was built without the
784 FIXED_NEVER_USERS option, and remove the above line from the runtime
785 configuration, but it would be better to create an alias for \/root/\
789 Q0040: How can I stop undeliverable bounce messages (e.g. to routeable, but
790 undeliverable, spammer senders) from clogging up the queue for days?
792 A0040: If at all possible, you should try to avoid getting into this situation
793 in the first place, for example, by verifying recipients so that you
794 do not accept undeliverable messages that lead to these bounces.
795 You can, however, configure Exim to discard failing bounce messages
796 early. Just set \ignore_bounce_errors_after\ to specify a (short) time
800 Q0041: What does the message \*unable to set gid=ddd or uid=ddd (euid=ddd):
801 local delivery to ... transport=ttt*\ mean?
803 A0041: Have you remembered to make Exim setuid \/root/\? It needs root privilege if
804 it is to do any local deliveries, because it does them ``as the user''.
805 Note also that the partition from which Exim is running (where the
806 binary is installed) must not have the \nosuid\ mount option set. You
807 can check this by looking at its \(/etc/fstab)\ entry (or \(/etc/vfstab)\,
808 depending on your OS).
811 Q0042: My ISP's mail server is rejecting bounce messages from Exim, complaining
812 that they have no sender. The SMTP trace does indeed show that the
813 sender address is \"<>"\. Why is the Sender on the bounce message empty?
815 A0042: Because the RFCs say it must be. Your ISP is at fault. Send them this
816 extract from RFC 2821 section 6.1 (\*Reliable Delivery and Replies by
819 If there is a delivery failure after acceptance of a message, the
820 receiver-SMTP MUST formulate and mail a notification message. This
821 notification MUST be sent using a null (\"<>"\) reverse path in the
822 envelope. The recipient of this notification MUST be the address
823 from the envelope return path (or the ::Return-Path:: header line).
824 However, if this address is null (\"<>"\), the receiver-SMTP MUST NOT
827 The reason that bounce messages have no sender is so that they
828 themselves cannot provoke further bounces, as this could lead to a
829 unending exchange of undeliverable messages.
832 Q0043: What does the error \*Unable to get interface configuration: 22 Invalid
835 A0043: This is an error that occurs when Exim is trying to find out the all the
836 IP addresses on all of the local host's interfaces. If you have lots of
837 virtual interfaces, this can occur if there are more than around 250 of
838 them. The solution is to set the option \local_interfaces\ to list just
839 those IP addresses that you want to use for making and receiving SMTP
843 Q0044: What does the error \*Failed to create spool file*\ mean?
845 A0044: Exim has been unable to create a file in its spool area in which to
846 store an incoming message. This is most likely to be either a
847 permissions problem in the file hierarchy, or a problem with the uid
848 under which Exim is running, though it could be something more drastic
849 such as your disk being full.
851 If you are running Exim with an alternate configuration file using a
852 command such as \"exim -C altconfig..."\, remember that the use of -C
853 takes away Exim's root privilege, unless \\TRUSTED_CONFIG_LIST\\
854 is set in \(Local/Makefile)\ and the corresponding file contains a
855 prefix which matches the alternative configuration file being used.
857 Check that you have defined the spool directory correctly by running
859 ==> exim -bP spool_directory
861 and examining the output. Check the mode of this directory. It should
862 look like this, assuming you are running Exim as user \/exim/\:
864 ==> drwxr-x--- 6 exim exim 512 Jul 16 12:29 /var/spool/exim
866 If there are any subdirectories already in existence, they should have
867 the same permissions, owner, and group. Check also that you haven't got
868 incorrect permissions on superior directories (for example, \(/var/spool)\).
869 Check that you have set up the Exim binary to be setuid \/root/\. It should
872 ==> -rwsr-xr-x 1 root xxx 502780 Jul 16 14:16 exim
874 Note that it is not just the owner that must be \/root/\, but also the third
875 permission must be \"s"\ rather than \"x"\.
878 Q0045: I see entries in the log that mention two different IP addresses for the
879 same connection. Why is this? For example:
881 ==> H=tip-mp8-ncs-13.stanford.edu ([36.173.0.189]) [36.173.0.156]
883 A0045: The actual IP address from which the call came is the final one.
884 Whenever there's something in parentheses in a host name, it is what the
885 host quoted as the domain part of an SMTP HELO or EHLO command. So in
886 this case, the client, despite being 36.173.0.156, issued the command
888 ==> EHLO [36.173.0.189]
890 when it sent your server the message. This is, of course, very
894 Q0046: A short time after I start Exim I see a defunct zombie process. What
897 A0046: Your system must be lightly loaded as far as mail is concerned. The
898 daemon sets off a queue runner process when it is started, but it only
899 tidies up completed child processes when it wakes up for some other
900 reason. When there's nothing much going on, you occasionally see
901 defunct processes like this waiting to be dealt with. This is
905 Q0047: On a reboot, or a restart of the mail system, I see the message \*Mailer
906 daemons: exim abandoned: unknown, malformed, or incomplete option
907 -bz sendmail*\. What does this mean?
909 A0047: \-bz-\ is a Sendmail option requesting it to create a `configuration freeze
910 file'. Exim has no such concept and so does not support the option. You
911 probably have a line like
913 ==> /usr/lib/sendmail -bz
915 in some start-up script (e.g. \(/etc/init.d/mail)\) immedately before
917 ==> /usr/lib/sendmail -bd -q15m
919 The first of these lines should be commented out.
922 Q0048: Whenever exim restarts it takes up to 3-5 minutes to start responding on
923 the SMTP port. Why is this?
925 A0048: Something else is hanging onto port 25 and not releasing it. One place
926 to look is \(/etc/inetd.conf)\ in case for any reason an SMTP stream is
930 Q0049: What does the log message \*no immediate delivery: more than 10 messages
931 received in one connection*\ mean?
933 A0049: A remote MTA sent a number of messages in a single SMTP session. Exim
934 limits the number of immediate delivery processes it creates as a
935 result of a single SMTP connection, in order to avoid creating a zillion
936 processes on systems that can have many incoming connections. If you are
937 dialing in to collect mail from your ISP, you should probably set
938 \smtp_accept_queue_per_connection\ to some number larger than 10, or
939 arrange to start a queue runner for local delivery (using \-ql-\)
940 immediately after collecting the mail.
943 Q0050: I am getting complaints from a customer who uses my Exim server for
944 relaying that they are being blocked with a \*Too many connections*\
947 A0050: See \smtp_accept_max\, \smep_accept_max_per_host\ and \smtp_accept_reserve\.
950 Q0051: When I test my system filter with \-bf-\, I get the error \*filtering
951 command "fail" is disabled*\. Why is this?
953 A0051: Use the \-bF-\ option to test system filters. This gives you access to the
954 freeze and fail actions.
957 Q0052: What does \*ridiculously long message header*\ in an error report mean?
959 A0052: There has to be some limit to the length of a message's header lines,
960 because otherwise a malefactor could open an SMTP channel to your host,
961 start a message, and then just send characters continuously until your
962 host runs out of memory. (Exim stores all the header lines in main
963 memory while processing a message). For this reason a limit is imposed
964 on the total amount of memory that can be used for header lines. The
965 default is 1MB, but this can be changed by setting \\HEADER_MAXSIZE\\ in
966 \(Local/Makefile)\ before building Exim. Exceeding the limit provokes
967 the ``ridiculous'' error message.
970 Q0053: Exim on my host responds to a connection with \"220 *****..."\ and
971 won't understand \\EHLO\\ commands.
973 A0053: This is the sign of a Cisco Pix ``Mailguard'' sitting in front of your
974 MTA. Pix breaks ESMTP and only does SMTP. It is a nuisance when you have
975 a secure MTA running on your box. Something like ``no fixup protocol
976 smtp 25'' in the Pix configuration is needed. It may be possible to do
977 this by logging into the Pix (using \^telnet^\ or \^ssh^\) and typing
978 \"no fixup smtp"\ to its console. (You may need to use other commands
979 before or after to set up configuration mode and to activate a changed
980 configuration. Consult your Pix documentation or expert.) See also
984 Q0054: I'm getting an Exim configuration error \*unknown rewrite flag
985 character (m) in line 386*\ but I haven't used any flags on my rewriting
988 A0054: You have probably forgotten to quote a replacement string that contains
992 Q0055: What does the error \*Failed to open wait-remote_smtp database: Invalid
995 A0055: This is something that happens if you have existing DBM hints files when
996 you install a new version of Exim that is compiled to use a different or
997 upgraded DBM library. The simplest thing to try is
999 ==> rm /var/spool/exim/db/*
1001 This removes all the hints files. Exim will start afresh and build new
1002 ones. If the symptom recurs, it suggests there is some problem with your
1006 Q0056: We are using Exim to send mail from our web server. However, whenever a
1007 user sends an email it gets sent with the return path (envelope sender)
1008 //apache@server_name.com// because the PHP script is running as
1011 A0056: You need to include \/apache/\ in the \trusted_users\ configuration option.
1012 Only trusted users are permitted to specify senders when mail is passed
1013 to Exim via the command line.
1016 Q0057: We've got people complaining about attachments that don't show up
1017 as attachments, but are included in the body of the message.
1019 A0057: In the past, these symptoms could be seen when some software passed a
1020 CRLF line terminated message via the command line, because Exim expected
1021 lines to be terminated by LF only, and so it preserved the CRs as data.
1022 Modern versions of Exim (4.21 or later) use heuristics to try to do the
1023 right thing with line endings.
1026 Q0058: What does the error \*failed to open DB file \(/var/spool/exim/db/retry)\:
1029 A0058: This error is most often caused when a hints file that was written with
1030 one version of the Berkeley DB library is read by another version.
1031 Sometimes this can happen if you change from a binary version of Exim to
1032 a locally compiled version. Or it can happen if you compile and install
1033 a new version of Exim after changing Berkeley DB versions. You can find
1034 out which version your Exim is using by running:
1036 ==> ldd /usr/sbin/exim
1038 The solution to the problem is to delete all the files in the
1039 \(/var/spool/exim/db)\ directory, and let Exim recreate them.
1042 Q0059: When my Outlook Express 6.0 client sends a STARTTLS command to begin a
1043 TLS session, Exim doesn't seem to receive it. The Outlook log shows
1046 ==> SMTP: 14:19:27 [tx] STARTTLS
1047 SMTP: 14:19:27 [rx] 500 Unsupported command.
1049 but the Exim debugging output shows this:
1051 ==> SMTP<< EHLO xxxx
1052 SMTP>> 250-yyyy Hello xxxx [nnn.nnn.nnn.nnn]
1055 250-AUTH CRAM-MD5 PLAIN LOGIN
1060 A0059: Turn off scanning of outgoing email in Norton Antivirus. If you aren't
1061 running Norton Antivirus, see if you are running some other kind of SMTP
1062 proxying, either on the client or on a firewall between the client and
1063 server. ``Unsupported command'' is not an Exim message.
1066 Q0060: Why am I getting the error \*failed to expand \"/data/lists/lists/${lc"\
1067 for require_files: \"${lc"\ is not a known operator*\ for this setting:
1069 ==> require_files = MAILMAN_HOME/lists/${lc:$local_part}/config.db
1071 A0060: The value of \"require_files"\ is a list in which each item is
1072 separately expanded. In other words, the splitting into items happens
1073 before the string expansion. You need either to double the colon, or
1074 switch to a different list separator.
1077 Q0061: What does the error \*Too many ``Received'' headers - suspected mail
1080 A0061: Whenever a message passes through an MTA, a ::Received:: header gets
1081 added. Exim counts the number of these headers in incoming messages. If
1082 there are more than the value of \received_headers_max\ (default 30),
1083 Exim assumes there is some kind of mail routing loop occurring. For
1084 example, host A passes the message to host B, which immediately passes
1085 it back to host A. Check the ::Received:: headers and the mail logs to
1086 determine exactly what is going on.
1088 One common cause of this problem is users with accounts on both systems
1089 who set up each one to forward to the other, thinking that will cause
1090 copies of all messages to be delivered on both of them.
1093 Q0062: When I try to start an Exim daemon with \-bd-\ it crashes. I ran a
1094 debugger and discovered that the crash is happening in the function
1095 \^^getservbyname()^^\. What's going on?
1097 A0062: What have you got in the file \(/etc/nsswitch.conf)\? If it contains this
1100 ==> services: db files
1102 try removing the \"db"\. Your system is trying to look in some kind of
1103 database before searching the file \(/etc/services)\, and there is an
1104 incompatibility the is causing the function \^^getservbyname()^^\ crash.
1105 This is an OS problem. See, for instance:
1107 \?http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=129025?\
1109 Another workaround in Exim is to set
1111 ==> daemon_smtp_port = 25
1113 in the configuration, to stop Exim calling \^^getservbyname()^^\.
1116 Q0063: When I try to start an Exim daemon, nothing happens. There is no
1117 process, and nothing is written to the Exim log.
1119 A0063: Check to see if anything is written to \(syslog)\. This problem can be
1120 caused by a permission problem that stops Exim from writing to its log
1121 files, especially if you've specified that they should be written
1122 somewhere other than under Exim's spool directory. You could also try
1123 running the daemon with debugging turned on.
1126 Q0064: When I run \"exim -d test@domain"\ it delivers fine, but when I send a
1127 message from the \^mail^\ command, I get \*User unknown*\ and the mail
1128 is saved in \(dead.letter)\.
1130 A0064: It looks as if Exim isn't being called by \^mail^\; instead it is
1131 calling some other program (probably Sendmail). Try running the command
1133 ==> /usr/sbin/sendmail -bV
1135 (If you get \*No such file or directory*\ or \*Command not found*\ you
1136 are running Solaris or IRIX. Try again with \(/usr/lib/sendmail)\.) The
1137 output should be something like this:
1139 ==> Exim version 4.05 #1 built 13-Jun-2002 10:27:15
1140 Copyright (c) University of Cambridge 2002
1142 If you don't see this, your Exim installation isn't fully operational.
1143 If you are running FreeBSD, see Q9201. For other systems, see Q0114.
1146 Q0065: When (as \/root/\) I use -C to run Exim with an alternate configuration
1147 file, it gives an error about being unable to create a spool file when
1148 trying to run an \%autoreply%\ transport. Why is this?
1150 A0065: When Exim is called with -C, it passes on -C to any instances of itself
1151 that it calls (so that the whole sequence uses the same config file).
1152 However, Exim gives up its root privilege if any user except \/root\/
1153 passes a -C option to use a non-default configuration file, and that
1154 includes the case where Exim re-execs itself to regain root privilege.
1155 Thus it can't write to the spool.
1157 The fix for this is to use the \\TRUSTED_CONFIG_LIST\\ build-time
1158 option. This defines a file containing a list of 'trusted' prefixes for
1159 configuration files. Any configuration file specified with -C, if it
1160 matches a prefix listed in that file, will be used without dropping root
1161 privileges (as long as it is not writeable by a non-root user).
1164 Q0066: What does the message \*unable to set gid=xxx or uid=xxx*\ mean?
1166 A0066: This message is given when an Exim process is unable to change uid or
1167 gid when it needs to, because it does not have root privilege. This is a
1168 serious problem that prevents Exim from carrying on with what it is
1169 doing. The two most common situations where Exim needs to change uid/gid
1170 are doing local deliveries and processing users' filter files. There are
1171 two common causes of this error:
1173 (1) You have forgotten to make the exim binary setuid to \/root/\. This
1174 means that it can never change uid/gid in any situation. Also, the
1175 setuid binary must reside on a disk partition that does not have the
1176 \"nosuid"\ mount option set.
1178 (2) The exim binary is setuid, but you have configured Exim so that,
1179 while trying to verify an address at SMTP time, it runs a router
1180 that needs to change uid/gid. Because Exim runs as \/exim/\ and not
1181 \/root/\ while receiving messages, the router is unable to change
1182 uid and therefore it cannot operate. The usual example of this is a
1183 \%redirect%\ router for users' filter files.
1185 Setting the \user\ or \check_local_user\ options on a \redirect\
1186 router causes this to happen (except in the special case when the
1187 redirection list is provided by the \data\ option and does not
1188 contain \":include:"\).
1190 The solution is to set \no_verify\ on the router that is causing the
1191 problem. This means that it is skipped when an address is being
1192 verified. In ``normal'' configurations where the router is indeed
1193 handling users' filter files, this is quite acceptable, because you
1194 do not usually need to process a filter file in order to verify that
1195 the local part is valid. See, for example, the \%userforward%\
1196 router in the default configuration.
1199 Q0067: What does the error \*too many unrecognized commands*\ mean?
1201 A0067: There have been instances of network abuse involving mail sent out by
1202 web servers. In most cases, unrecognizable commands are sent as part of
1203 the SMTP session. A real MTA never sends out such invalid commands. Exim
1204 allows a few unrecognized commands in a session to permit humans who are
1205 testing to make a few typos (it responds with a 5xx error). However, if
1206 Exim receives too many such commands, it assumes that it is dealing with
1207 an abuse of some kind, and so it drops the connection.
1210 Q0068: Exim times out when trying to connect to some hosts, though those hosts
1211 are known to be up and running. What's the problem?
1213 A0068: There could be a number of reasons for this (see also Q0017). The
1214 obvious one is that there is a networking problem between the hosts.
1215 If you can ping between the hosts or connect in other ways, the problem
1216 might be caused by ECN (Explicit Congestion Notification) being enabled
1217 in your kernel. ECN uses TCP flags originally assigned to TOS - it's a
1218 "new" invention, and some hosts and routers are known to be confused if
1219 a client uses it. If you are running Linux, you can turn ECN off by
1220 running this command:
1222 ==> /bin/echo "0" > /proc/sys/net/ipv4/tcp_ecn
1224 This has also been reported to cure web connection problems from Mozilla
1225 and Netscape browsers in Linux when there were no problems with Windows
1229 Q0069: What does the error \*SMTP data timeout (message abandoned) on connection
1232 A0069: It means that there was a timeout while Exim was reading the contents of
1233 a message on an incoming SMTP connection. That is, it had successfully
1234 accepted a MAIL command, one or more RCPT commands, and a DATA command,
1235 and was in the process of reading the data itself. The length of timeout
1236 is controlled by the \smtp_receive_timeout\ option.
1238 If you get this error regularly, the cause may be incorrect handling of
1239 large packets by a router or firewall. The maximum size of a packet is
1240 restricted on some links; routers should split packets that are larger.
1241 There is a feature called ``path MTU discovery'' that enables a sender
1242 to discover the maximum packet size over an entire path (multiple
1243 Internet links). This can be broken by misconfigured firewalls and
1244 routers. There is a good explanation at \?http://www.netheaven.com/pmtu.html?\.
1245 Reducing the MTU on your local network can sometimes work round this
1246 problem. See Q0017 (3) for further discussion.
1249 Q0070: What does the error \*SMTP command timeout on connection from...*\ mean?
1251 A0070: Exim was expecting to read an SMTP command from the client, but no
1252 command was read within the \smtp_receive_timeout\ time limit.
1255 Q0071: What does the error \*failed to open DB file \(/var/spool/exim//db/retry)\:
1256 Illegal argument*\ mean?
1258 A0071: See Q0058. The cause of this error is usually the same.
1261 Q0072: Exim will deliver to normal aliases, and aliases that are pipes or
1262 files, but it objects to aliases that involve \":include:"\ items,
1263 complaining that it can't change gid or uid. Why is this?
1265 A0072: See Q0066 for a general answer. The problem happens during verification
1266 of an incoming SMTP message, not during delivery itself. In this
1267 particular case, you must have set up your aliasing router with a \user\
1268 setting. This causes Exim to change uid/gid when reading \":include:"\
1269 files. If you do not need the detailed verification provided by the
1270 router, the easy solution is to set \no_verify\ so that the router isn't
1271 used during verification.
1273 Otherwise, if you set \user\ on the router in order to provide a user
1274 for delivery to pipes or files, one solution is to put the \user\
1275 setting on the transports instead of on the router. You may need to
1276 create some special transports just for this router. The alternative is
1277 to supply two different routers, one with \user\ and \no_verify\, and
1278 the with \verify_only\ but no \user\ setting.
1281 Q0073: I'm seeing log file corruption, with parts of log lines getting mangled
1282 by other log entries.
1284 A0073: The only time this has been seen is when several servers were writing to
1285 the same log files over NFS. Exim assumes that its log file is on local
1286 disk, and using NFS, especially for more than one server, will not work.
1289 Q0074: What does the error message \*remote delivery process count got out of
1292 A0074: Exim uses subprocesses for remote deliveries; this error means that the
1293 master process expected to have a child process running, but found there
1294 were none. Prior to release 4.11, this error could be caused by running
1295 Exim under \^strace^\ on a Linux system, because stracing causes
1296 children to be ``stolen'' such that a parent that tries to wait for
1297 ``any of my children'' is told that it has none. Current releases of
1298 Exim have code to get round this problem.
1301 Q0075: I'm using LDAP, and some email addresses that contain special characters
1302 are causing parsing errors in my LDAP lookups.
1304 A0075: You should be using \"${quote_ldap:$local_part}"\ instead of just
1305 \"$local_part"\ in your lookups.
1308 Q0076: I've configured Exim to use \^syslog^\ for its logs, with the main and
1309 reject logs sent to different files, but whenever a message is rejected,
1310 I get one message on the reject log and two messages on the main log.
1312 A0076: You are probably putting your reject items into the main log as well;
1313 remember \^syslog^\ levels are inclusive (for example, \"mail.info"\
1314 includes all higher levels, so a \"mail.notice"\ message will be caught
1315 by a \"mail.info"\ descriptor).
1316 Test this by running the command:
1318 ==> logger -p mail.notice test
1320 and seeing which logs it goes into. From Exim release 4.31 it is
1321 possible to disable the rejectlog by setting \write_rejectlog\ false.
1324 Q0077: I've installed Exim and it is delivering mail just fine. However, when I
1325 try to read mail from my PC I get \*connection rejected*\ or \*unable to
1331 Q0078: Exim is logging the unknown SMTP command \"XXXX"\ from my client hosts,
1332 and they are unable to authenticate.
1334 A0078: This is a sign of a Cisco PIX firewall getting in the way. It does not
1335 support ESMTP, and turns EHLO commands into XXXX. You should configure
1336 the Pix to leave SMTP alone; see Q0053 for how to do this.
1339 Q0079: Our new PIX firewall is causing problems with incoming mail. How can
1342 A0079: See Q0053 and Q0078. If some messages get through and others do not,
1346 Q0080: Am I to understand that the database lookups must only return one value?
1347 They can not return a list of values? The documentation seems to
1348 indicate that it's possible to return a list.
1350 A0080: Lookups can be used in two different situations, and what they return is
1351 different in the two cases. (Be thankful Exim 3 is gone; there was yet
1354 (1) You can use a lookup in any expanded string. The syntax is
1356 ==> ${lookup ..... }
1358 In this case, whatever is looked up replaces the expansion item. It
1359 may be one value or a list of values. Whether a single value or a
1360 list is acceptable or not depends on where you are using the string
1361 expansion. If it is for an option that expects just one value, then
1362 only one value is allowed (for example).
1364 (2) You can make use of the lookup mechanism to test whether something
1365 (typically a host name or IP address) is in a list. For example,
1367 ==> hosts = a : b : c
1369 in an ACL tests whether the calling host's name matches ``a'', or
1370 ``b'', or ``c''. Now, suppose you want to keep the list of names in
1371 a database, or cdb file, or NIS map, or... By writing
1373 ==> hosts = pgsql;select ....
1375 you are saying to Exim: ``Run this lookup; if it succeeds, behave as
1376 if the host is in the list; if it fails, the host is not in the
1377 list.'' You are using the indexing mechanism of the database as a
1378 fast way of checking a list. A simpler example is
1380 ==> hosts = lsearch;/some/file
1382 where the file contains the list of hosts to be searched.
1384 The complication happens when a list is first expanded before being
1385 interpreted as a list. This happens in a lot of cases. You can therefore
1386 write either of these:
1388 ==> hosts = cdb;/some/file
1389 hosts = ${lookup{something}cdb{/some/file}}
1391 but they have different meanings. The first means ``see if the host name
1392 is in the list in this file''. The second means ``run this lookup and
1393 use the result of the lookup as a list of host items to check''. In the
1394 second case, the list could contain multiple values (colon separated),
1395 and one of those values could even be ``cdb;/some/file''.
1397 Flexibility does lead to complexity, I'm afraid.
1400 Q0081: What does \*error in redirect data: included file xxxx is too big*\
1403 A0081: You are trying to include a very large file in a redirection list, using
1404 the \":include:"\ feature. Exim has a built-in limit on the size, as a
1405 safety precaution. The default is 1 megabyte. If you want to increase
1406 this, you have to rebuild Exim. In your \(Local/Makefile)\, put
1408 ==> MAX_INCLUDE_SIZE = whatever
1410 and then rebuild Exim. The value is a number of bytes, but you can give
1411 it as a parenthesized arithmetic expression such as \"(3*1024*1024)"\.
1412 However, an included file of more than a megabyte is likely to be quite
1413 inefficient. How many addresses does yours contain? You get the best
1414 performance out of Exim if you arrange to send mailing list messages
1415 with no more than about 100 recipients (in order to get parallelism in
1419 Q0082: What does \*relocation error: /lib/libnss_dns.so.2: symbol
1420 __libc_res_nquery, version GLIBC_PRIVATE not defined in file
1421 libresolv.so.2 with link time reference*\ mean?
1423 A0082: You have updated \^glibc^\ while an Exim daemon is running. Stop and
1427 Q0083: Netscape on Unix is sending messages containing an unqualified user name
1428 in the ::Sender:: header line, which Exim is rejecting because I have
1429 set \"verify = header_syntax"\. How can I fix this?
1431 A0083: The only thing you can do in Exim is to set the
1432 \sender_unqualified_hosts\ option to allow unqualified sender addresses
1433 form the relevant hosts; of course, this applies to all sender
1434 addresses, not just the ::Sender:: header line.
1436 Alternatively, you can configure Netscape not to include the header line
1437 in the first place. Add the following line to the
1438 \($HOME/.netscape/preferences.js)\ and \($HOME/.netscape/liprefs.js)\
1441 ==> user_pref("mail.suppress_sender_header", true);
1443 Netscape must be shut down while doing this.
1446 Q0084: I want to set up an alias that pipes a message to \^gpg^\ and then pipes
1447 the result to \^mailx^\ to resubmit the message, but when I use my
1448 tested command in an alias file, I get an error from \^gpg^\.
1450 A0084: Probably you are using a shell command with two pipe symbols in it. An
1453 ==> gpg-xxx: "|gpg <options> | mailx <options"
1455 does not work, because Exim does not run pipes under a shell by default.
1456 You must call a shell explicitly if you want to make use of the shell's
1457 features for double-piping, either by piping to \"/bin/sh"\ with a
1458 suitable \"-c"\ option, or by piping to a shell script.
1461 Q0085: I see a lot of \*rejected EHLO ... syntactically invalid argument(s)*\.
1462 I know it's because of the underscore in the host name, but is there a
1463 switch to allow Exim to accept mail from such hosts?
1465 A0085: Yes. Add this to your configuration:
1467 ==> helo_allow_chars = _
1469 For more seriously malformed host names, see \helo_accept_junk_hosts\.
1473 Q0086: What does \*SMTP protocol violation: synchronization error (next input
1474 sent too soon)*\ mean?
1476 A0086: SMTP is a ``lock-step'' protocol, which means that, at certain points in
1477 the protocol, the client must wait for the server to respond before
1478 sending more data. Exim checks for correct behaviour, and issues this
1479 error if the client sends data too soon. This protects against
1480 malefactious clients who send a bunch of SMTP commands (usually to
1481 transmit spam) without waiting for any replies.
1483 This error is also provoked if a client unexpectedly tries to start up a
1484 TLS session immediately on connection, without using the STARTTLS
1485 command. See Q1707 for a discussion of this case.
1488 Q0087: What does \*rejected after DATA: malformed address: xx@yy may not follow
1489 <xx@yy> : failing address in "from" header*\ mean?
1491 A0087: Your DATA ACL contains
1493 ==> verify = header_syntax
1495 and an incoming message contained the line
1497 ==> From: xx@yy <xx@yy>
1499 This is syntactically invalid. The contents of an address in a header
1500 line are either just the address, or a ``phrase'' followed by an address
1501 in angle brackets. In the latter case, the ``phrase'' must be quoted if
1502 it contains special characters such as @. The following are valid
1503 versions of the bad header:
1506 From: "xx@yy" <xx@yy>
1508 though why on earth anything generates this kind of redundant nonsense I
1512 Q0088: The Windows mailer SENDFILE.EXE sometimes hangs while trying to send a
1513 message to Exim 4, and eventually times out. It worked flawlessly with
1514 Exim 3. What has changed?
1516 A0088: Exim 4 sets an obscure TCP/IP parameter called TCP_NODELAY. This
1517 disables the "Nagle algorithm" for the TCP/IP transmission. The Nagle
1518 algorithm can improve network performance in interactive situations such
1519 as a human typing at a keyboard, by buffering up outgoing data until the
1520 previous packet has been acknowledged, and thereby reducing the number
1521 of packets used. This is not relevant for mail transmission, which
1522 mostly consists of quite large blocks of data; setting TCP_NODELAY
1523 should improve performance. However, it seems that some Windows clients
1524 do not function correctly if the server turns off the Nagle algorithm.
1525 If you are using Exim 4.23 or later, you can set
1527 ==> tcp_nodelay = false
1529 This stops Exim setting TCP_NODELAY on the sockets created by the
1533 Q0089: What does the error \*kernel: application bug: exim(12099) has SIGCHLD
1534 set to SIG_IGN but calls wait()*\ mean?
1536 A0089: This was a bad interaction between a change to the Linux kernel and some
1537 ``belt and braces'' programming in Exim. The following explanation is
1538 taken from Exim's change log:
1540 When Exim is receiving multiple messages on a single connection, and
1541 spinning off delivery processess, it sets the SIGCHLD signal handling to
1542 SIG_IGN, because it doesn't want to wait for these processes. However,
1543 because on some OS this didn't work, it also has a paranoid call to
1544 \^waitpid()^\ in the loop to reap any children that have finished. Some
1545 versions of Linux now complain (to the system log) about this
1546 ``illogical'' call to \^waitpid()^\. I have therefore put it inside a
1547 conditional compilation, and arranged for it to be omitted for Linux.
1549 I am pretty sure I caught all the places in Exim where this happened.
1550 However, there are still occasional reports of this error. I have not
1551 heard of any resolutions, but my current belief is that they are caused
1552 by something that Exim calls falling foul of the same check. There was
1553 at one time a suspicion that the IPv6 stack was involved.
1556 Q0090: I can't seem to get a pipe command to run when I include a \"${lookup"\
1562 Q0091: Why is Exim giving the error \*Failed to send message from address_reply
1563 transport*\ when I run it using -C to specify an alternate
1569 Q0092: The error message \*Program received signal SIGINT, Interrupt.*\ occurs
1570 when I try to use Exim with PostgreSQL.
1572 A0092: Check that you have not set
1574 ==> log_statement=true
1576 in the PostgreSQL configuration file. It seems that this causes
1577 PostgreSQL to return logging information as the first row in a query
1578 result, which totally confuses Exim.
1582 1. BUILDING AND INSTALLING
1584 Q0101: I'm having a problem with an Exim RPM.
1586 A0101: Normally the thing to do if you have a problem with an RPM package is
1587 to contact the person who built the package first, not the person who
1588 made the software that's in the package. You can usually find out who
1589 made a package using the following command:
1591 ==> rpm --query --package --queryformat '%{PACKAGER}\n' <rpm-package-file>
1593 where \[rpm-package-file]\ is the actual file, e.g. \(exim-3.03-2.i386.rpm)\.
1594 Or, if the package is installed on your system:
1596 ==> rpm --query --queryformat '%{PACKAGER}\n' <package-name>
1598 where \[package-name]\ is the name component of the package, e.g. \"exim"\.
1599 If the packager is unable or unwilling to help, only then should you
1600 contact the actual author or associated mailing list of the software.
1602 If you discover through the querying process that you can't tell who
1603 the person (or company or group) is who built the package, or that they
1604 no longer exist at the given address, then you should reconsider
1605 whether you want a package from an unknown source on your system.
1607 If you discover through the querying process that you yourself are the
1608 person who built the package, then you should either (a) contact the
1609 author or associated mailing list, or (b) reconsider whether you ought
1610 to be building and distributing RPM packages of software you don't
1613 Similar rules of thumb govern other binary package formats, including
1614 debs, tarballs, and POSIX packages.
1617 Q0102: I can't get Exim to compile with Berkeley DB version 2.x or 3.x.
1619 A0102: Have you set \"USE_DB=yes\" in \(Local/Makefile)\? This causes Exim to use the
1620 native interface to the DBM library instead of the compatibility
1621 interface, which needs a header called \(ndbm.h)\ that may not exist on your
1625 Q0103: I'm getting an \*undefined symbol*\ error for \"hosts_ctl"\ when I try to
1626 build Exim. (On some systems this error is \*undefined reference to
1629 A0103: You should either remove the definition of \\USE_TCP_WRAPPERS\\ or add
1630 \"-lwrap"\ to your \\EXTRALIBS\\ setting in Local/Makefile.
1633 Q0104: I'm about to upgrade to a new Exim release. Do I need to ensure the
1634 spool is empty, or take any other special action?
1636 A0104: It depends on where you are coming from.
1638 (1) If you are changing to release 4.00 or later from a release prior to
1639 4.00, you will need to make changes to the run time configuration file.
1640 See the file \(doc/Exim4.upgrade)\ for details. If you are coming from
1641 before release 3.00, you should also see \(doc/Exim3.upgrade)\.
1643 (2) If you are upgrading from an Exim 4 release to a later release, you
1644 do not need to take special action. New releases are made backwards
1645 compatible with old spool files and hints databases, so that upgrading
1646 can be done on a running system. All that should be necessary is to
1647 install a new binary and then HUP the daemon.
1649 \**Warning**\: If you have changed the release of your DBM library, so
1650 that your new Exim is linked with a different release than the old one,
1651 you may encounter errors when Exim attempts to access the old hints
1652 databases. See Q0055.
1655 Q0105: What does the error \*install-info: command not found*\ mean?
1657 A0105: You have set \\INFO_DIRECTORY\\ in your \(Local/Makefile)\, and Exim is trying
1658 to install the Texinfo documentation, but cannot find the command called
1659 \(install-info)\. If you have a version of Texinfo prior to 3.9, you
1660 should upgrade. Otherwise, check your installation of Texinfo to see why
1661 the \(install-info)\ command is not available.
1664 Q0106: Exim doesn't seem to be recognizing my operating system type correctly,
1665 and so is failing to build.
1667 A0106: Run the command \"scripts/os-type -generic"\. The output should be one of
1668 the known OS types, and should correspond to your operating system. You
1669 can see which OS are supported by obeying \"ls OS/Makefile-*"\ and looking
1670 at the file name suffixes.
1672 If there is a discrepancy, it means that the script is failing to
1673 interpret the output from the \"uname"\ command correctly, or that the
1674 output is wrong. Meanwhile, you can build Exim by obeying
1676 ==> EXIM_OSTYPE=xxxx make
1678 instead of just \"make"\, provided you are running a Bourne-compatible
1679 shell, or otherwise by setting \\EXIM_OSTYPE\\ correctly in your
1680 environment. It is probably best to start again from a clean
1681 distribution, to avoid any wreckage left over from the failed attempt.
1684 Q0107: Exim fails to build, complaining about the absence of the \"killpg"\
1687 A0107: This function should be present in all modern flavours of Unix. If you
1688 are using an older version, you should be able to get round the problem
1691 ==> #define killpg(pgid,sig) kill(-(pgid),sig)
1693 into the file called \(OS/os.h-xxx)\, where xxx identifies your operating
1694 system, and is the output of the command \"scripts/os-type -generic"\.
1697 Q0108: I'm getting an unresolved symbol \"ldap_is_ldap_url"\ when trying to build
1700 A0108: You must have specified \"LOOKUP_LDAP=yes"\ in the configuration. Have you
1701 remembered to set \"-lldap"\ somewhere (e.g. in \\LOOKUP_LIBS\\)? You need that
1702 in order to get the LDAP library scanned when linking.
1705 Q0109: I'm getting an unresolved symbol \"mysql_close"\ when trying to build Exim.
1707 A0109: You must have specified \"LOOKUP_MYSQL=yes"\ in the configuration. Have you
1708 remembered to set \"-lmysqlclient"\ somewhere (e.g. in \\LOOKUP_LIBS\\)? You
1709 need that in order to get the MySQL library scanned when linking.
1712 Q0110: I'm trying to build Exim with PAM support. I have included \"-lpam"\ in
1713 \\EXTRALIBS\\, but I'm still getting a linking error:
1715 ==> /lib/libpam.so: undefined reference to `dlerror'
1716 /lib/libpam.so: undefined reference to `dlclose'
1717 /lib/libpam.so: undefined reference to `dlopen'
1718 /lib/libpam.so: undefined reference to `dlsym'
1720 A0110: Add \"-ldl"\ to \\EXTRALIBS\\. In some systems these dynamic loading functions
1721 are in their own library.
1724 Q0111: I'm getting the error \*db.h: No such file or directory*\ when I try to
1727 A0111: This problem has been seen with RedHat 7.0, but could also happen in
1728 other environments. If your system is using the DB library, you
1729 need to install the DB development package in order to build Exim.
1730 The package is called something like \"db3-devel-3.1.14-16.i386.rpm"\ for
1731 Linux systems, but you should check which version of DB you have
1732 installed (current releases are DB 4).
1735 Q0112: I'm getting the error \*/usr/bin/ld: cannot find -ldb*\ when I try to
1738 A0112: This is probably the same problem as Q0111.
1741 Q0113: I've compiled Exim and I've managed to start it but there was one
1742 problem - it always complained that \(libmsqlclient.so.10)\ was not found,
1743 even though this file is in \(/usr/local/lib/mysql/)\.
1745 A0113: Solaris: ensure you have this in your \(Local/Makefile)\:
1747 ==> LOOKUP_LIBS=-L/usr/local/lib/mysql -R/usr/local/lib/mysql
1749 Net/Open/FreeBSD: Run this command (or ensure it gets run automatically
1752 ==> ldconfig -m /usr/local/lib/mysql
1754 Linux: add \(/usr/local/lib/mysql)\ to \(/etc/ld.so.conf)\ and re-run \(ldconfig)\.
1757 ==> -Wl,-rpath -Wl,/usr/local/lib/mysql
1759 to EXTRA_LIBS and then re-link (this is similar to the Solaris solution
1760 above). This will probably also work on other systems that use GNU
1764 Q0114: How can I remove Sendmail from my system? I've built Exim and run \"make
1765 install"\, but it still doesn't seem to be fully operational.
1767 A0114: If you are running FreeBSD, see Q9201. Otherwise, you need to arrange
1768 that whichever of the paths \(/usr/sbin/sendmail)\ or \(/usr/lib/sendmail)\
1769 exists on your system is changed to refer to Exim. For example, you
1770 could use these commands (as \/root/\):
1772 ==> mv /usr/sbin/sendmail /usr/sbin/sendmail.original
1773 chmod u-s /usr/sbin/sendmail.original
1774 ln -s /path/to/exim /usr/sbin/sendmail
1776 The second command removes the setuid privilege from the old MTA, as a
1777 general safety precaution. In the third command, substitute the actual
1778 path to the Exim binary for \(/path/to/exim)\.
1781 Q0115: What does \*Can't open \(../scripts/newer)\: No such file or directory*\
1782 mean? I got it while trying to build Exim.
1784 A0115: You are using FreeBSD, or another OS that has a \^make^\ command which
1785 tries to optimize the running of commands. Exim's \(Makefile)\ contains
1786 targets with sequential commands like this:
1789 @cd pcre; $(MAKE) SHELL=$(SHELL) AR="$(AR)" $(MFLAGS) CC="$(CC)" \
1790 CFLAGS="$(CFLAGS) $(PCRE_CFLAGS)" \
1791 RANLIB="$(RANLIB)" HDRS="$(PHDRS)" \
1792 INCLUDE="$(INCLUDE) $(IPV6_INCLUDE) $(TLS_INCLUDE)"
1793 @if $(SHELL) $(SCRIPTS)/newer pcre/libpcre.a exim; then \
1794 /bin/rm -f exim eximon.bin; fi
1796 The second command assumes that the \"cd pcre"\ in the first command is
1797 no longer in effect. If you have \"-j3"\ in your default set of
1798 \"MAKEFLAGS"\, FreeBSD \^make^\ tries to optimize, and ends up up with both
1799 commands in the same shell process. The result is that \"$(SCRIPTS)"\
1800 (which has a value of \"../scripts"\) is not found.
1802 The simplest solution is to force \^make^\ to use backwards compatibility
1803 mode with each command in its own shell, by using the \-B\ flag. To
1804 ensure that this happens throughout the build, it's best to export it in
1812 Q0116: I have tried to build Exim with Berkeley DB 3 and 4, but I always get
1815 A0116: One common problem, especially when you have several different versions
1816 of BDB installed on the same host, is that the header files and library
1817 files for BDB are not in a standard place. You therefore need to tell
1818 Exim where they are, by setting INCLUDE and DBMLIB in your
1819 \(Local/Makefile)\. For example, you could use this when you want to
1822 ==> INCLUDE=-I/usr/local/include/db-4.1
1823 DBMLIB=/usr/local/lib/db-4.1/libdb.a
1825 Specifying the complete library file like this will cause it to be
1826 statically linked with Exim. You'll have to check to see where these
1827 files are on your system. For example, on FreeBSD 5, the header is in
1828 \(/usr/local/include/db4)\ and the library is in \(/usr/local/lib)\ and
1829 called \(libdb4)\. In that environment, you could use:
1831 ==> INCLUDE=-I/usr/local/include/db4
1832 DBMLIB=-L/usr/local/lib -ldb4
1834 This time, DBMLIB is specifying the library directory (\(/usr/local/lib)\)
1835 and the name of the library (\(db4)\) separately. The name of the actual
1836 library file is \(/usr/local/lib/libdb4.something)\. If the library was
1837 compiled for dynamic linking, that will be used.
1840 Q0117: Is there a quick walk-through of an Exim install from source anywhere?
1842 A0117: Here! This is a contribution from a RedHat user, somewhat edited. On
1843 other operating systems things may be slightly different, but the
1844 general approach is the same.
1846 (1) Install the db needed for Exim. This needs to be done first if you
1847 don't have a DBM library installed. Go to \?http://www.sleepycat.com?\
1848 and download \(db-4.1.25.tar.gz)\, or whatever the current release is.
1851 ==> gunzip db-4.1.25.tar.gz
1852 tar -xvf db-4.1.25.tar
1859 (2) Add a user for use by Exim, unless you want to use an existing user
1864 (3) Now you can prepare to build Exim. Go to \?http://www.exim.org?\ or
1865 one of its mirrors, or the master ftp site
1866 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4?\, and download
1867 \(exim-4.20.tar.gz)\ or whatever the current release is. Then:
1869 ==> gunzip exim-4.20.tar.gz
1870 tar -xvf exim-4.20.tar
1872 cp src/EDITME Local/Makefile
1873 cp exim_monitor/EDITME Local/eximon.conf
1875 (4) Edit \(Local/Makefile)\:
1877 Comment out EXIM_MONITOR= unless you want to install the Exim
1878 monitor (it requires X-windows).
1880 Set the user you want Exim to use for itself:
1884 If your DBM library is Berkeley DB, set up to use its native interface:
1888 Make sure Exim's build can find the DBM library and its headers. If
1889 you've installed Berkeley DB 4 you'll need to have settings like this
1890 in \(Local/Makefile)\:
1892 ==> INCLUDE=-I/usr/local/BerkeleyDB.4.1/include
1893 DBMLIB=/usr/local/BerkeleyDB.4.1/lib/libdb.a
1895 (Check that the first directory contains the db.h file and that the
1896 second library exists.)
1898 You don't need to change anything else, but you might want to review
1899 the default settings in the ``must specify'' section.
1901 (4) Build Exim by running the \/make/\ command.
1903 (5) Install Exim by running, as \/root/\:
1907 You must be \/root/\ to do this. You do not have to be root for any of
1908 the previous building activity.
1910 (6) Run some tests on Exim; see if it will do local and remote
1911 deliveries. Change the configuration if necessary (for example,
1912 uncommenting \group\ on the \%local_delivery%\ transport if you don't
1913 use a ``sticky bit'' directory).
1915 (7) Change Sendmail to Exim (of course you need to have had Sendmail
1916 installed to do this).
1918 ==> /etc/init.d/sendmail stop
1919 mv /usr/sbin/sendmail /usr/sbin/sendmail.org
1920 ln -s /usr/exim/bin/exim /usr/sbin/sendmail
1921 /etc/init.d/sendmail start
1923 (8) Check the Exim log. Either use the Exim monitor, or:
1925 ==> tail -f /var/spool/exim/log/mainlog
1928 Q0118: I've set \"LOOKUP_INCLUDE=-I/client/include"\ in Local/Makefile, but the
1929 compilation of \^exim_dumpdb^\ is ignoring this option and failing. Why?
1931 A0118: LOOKUP_INCLUDE is the special include file for lookup modules in Exim
1932 (e.g. mysql, LDAP). Confusingly, it doesn't apply to basic DBM code
1933 which is used also for other things. Try setting INCLUDE and DBMLIB
1934 instead. For example:
1937 INCLUDE=-I/client/include
1938 DBMLIB=/client/lib/libdb.a
1941 Q0119: I know there are some 3rd-party patches for Exim, for exiscan and
1942 other things. Where are they?
1944 A0119: Exiscan is at \?http://duncanthrax.net/exiscan-acl/?\.
1946 Scanexi is at \?http://w1.231.telia.com/~u23107873/scanexi.html?\
1948 A sample \^^local_scan()^^\ function for interfacing to \^uvscan^\ is
1949 at \?http://www.dcs.qmul.ac.uk/~mb/local_scan/?\.
1951 An interface to SpamAssassin at SMTP time is at
1952 \?http://marc.merlins.org/linux/exim/sa.html?\.
1954 A mini-HOWTO (PDF file) about scanning and virus scanning, and some RPMs
1955 can be found at \?http://www.timj.co.uk/linux/exim.php?\.
1958 Q0120: I'm trying to compile with LOOKUP_WHOSON, but I keep getting \*In
1959 function `whoson_find': undefined reference to `wso_query'*\.
1961 A0120: Try adding \"-lwhoson"\ to your LOOKUP_LIBS setting in \(Local/Makefile)\.
1965 2. ROUTING IN GENERAL
1967 Q0201: How can I arrange that messages larger than some limit are handled by
1970 A0201: You can use a \condition\ option on the router line this:
1972 ==> condition = ${if >{$message_size}{100K}{yes}{no}}
1975 Q0202: Can I specify a list of domains to explicitly reject?
1977 A0202: Set up a named domain list containing the domains in the first section
1978 of the configuration, for example:
1980 ==> domainlist reject_domains = list:of:domains:to:reject
1982 You can use this list in an ACL to reject any SMTP recipients in those
1983 domains. You can also give a customized error message, like this:
1985 ==> deny message = The domain $domain is no longer supported
1986 domains = +reject_domains
1988 If you also want to reject these domains in messages that are submitted
1989 from the command line (not using SMTP), you need to set up a router to
1994 domains = +reject_domains
1996 data = :fail: The domain $domain is no longer supported
1999 Q0203: How can I arrange to do my own qualification of non-fully-qualified
2000 domains, and then pass them on to the next router?
2002 A0203: If you have some list of domains that you want to qualify, you can do
2003 this using a redirect router. For example,
2008 data = ${quote:$local_part}@$domain.c.com
2010 This adds \".c.com"\ to any domain that matches \"*.a.b"\.
2011 If you want to do this in conjunction with a \%dnslookup%\ router, the
2012 \widen_domains\ option of that router may be another way of achieving
2016 Q0204: Every system has a \"nobody"\ account under which httpd etc run. I would
2017 like to know how to restrict mail which comes from that account to users
2020 A0204: Set up a first router like this:
2024 senders = nobody@your.domain
2025 domains = ! +local_domains
2027 data = :fail: Nobody may not mail off-site
2029 This assumes you have defined \+local_domains\ as in the default
2033 Q0205: How can I get Exim to deliver to me locally and everyone else at the same
2034 domain via SMTP to the MX record specified host?
2036 A0205: Create an \%accept%\ router to pick off the one address and pass it to
2037 an appropriate transport. Put this router before the one that does MX
2044 transport = local_delivery
2046 In the transport you will have to specify the \user\ option. An
2047 alternative way of doing this is to add a condition to the router that
2048 does MX lookups to make it skip your address. Subsequent routers can then
2049 deliver your address locally. You'll need a condition like this:
2052 ${if and {{eq{$domain}{dom.com}}{eq{$local_part}{me}}}{no}{yes}}
2055 Q0206: How can I get Exim to deliver certain domains to a different SMTP port
2058 A0206: You must set up a special \%smtp%\ transport, where you can specify the
2059 \port\ option, and then set up a router to route the domains to that
2060 transport. There are two possibilities for specifying the host:
2062 (1) If you use a \%manualroute%\ router, you can specify the local host
2063 in the router options. You must also set
2067 so that it does not object to sending to the local host.
2069 (2) If you use a router that cannot specify hosts (for example, an
2070 \%accept%\ router with appropriate conditions), you have to specify
2071 the host using the \hosts\ option of the transport. In this case,
2072 you must also set \allow_localhost\ on the transport.
2075 Q0207: Why does Exim lower-case the local-part of a non-local domain when
2078 A0207: Because \caseful_local_part\ is not set (in the default configuration)
2079 for the \%dnslookup%\ router. This does not matter because the local
2080 part takes no part in the routing, and the actual local part that is
2081 sent out in the RCPT command is always the original local part.
2084 Q0208: I can't get a lookup to work in a domain list. I'm trying this:
2086 ==> domainlist local_domains = @:localhost:${lookup pgsql{SELECT ...
2088 A0208: Does the lookup return a colon separated list of domains? If not, you
2089 are using the wrong kind of lookup. The most common way of using a
2090 lookup in a domain list is something like this:
2092 ==> domainlist local_domains = @:localhost:pgsql;SELECT ...
2094 Using that syntax, if the query succeeds, the domain is considered to be
2095 in the list. The value that is returned is not relevant.
2099 3. ROUTING TO REMOTE HOSTS
2101 Q0301: What do \*lowest numbered MX record points to local host*\ and \*remote
2102 host address is the local host*\ mean?
2104 A0301: They mean exactly what they say. Exim expected to route an address to a
2105 remote host, but the IP address it obtained from a router was for the
2106 local host. If you really do want to send over TCP/IP to the local host
2107 (to a different version of Exim or another MTA, for example), see Q0206.
2109 More commonly, these errors arise when Exim thinks it is routing some
2110 foreign domain. For example, the router configuration causes Exim to
2111 look up the domain in the DNS, but when Exim examines the DNS output,
2112 either the lowest numbered MX record points at the local host, or there
2113 are no MX records, and the address record for the domain contains an
2114 IP address that belongs to the local host.
2116 There has been a rash of instances of domains being deliberately set up
2117 with MX records pointing to \"localhost"\ (or other names with A records
2118 that specify 127.0.0.1), which causes this behaviour. You can use the
2119 \ignore_target_hosts\ option to get Exim to ignore these records. The
2120 default contiguration does this. For more discussion, see Q0319. For
2123 (1) If the domain is meant to be handled as a local domain, there
2124 is a problem with the configuration, because it should not then have
2125 been looked up in the DNS. Check the \domains\ settings on your
2128 (2) If the domain is one for which the local host is providing a
2129 relaying service (called ``mail hubbing''), possibly as part of a
2130 firewall, you need to set up a router to tell Exim where to send
2131 messages addressed to this domain, because the DNS directs them to
2132 the local host. You should put a router like this one before the one
2133 that does DNS lookups:
2136 driver = manualroute
2137 transport = remote_smtp
2138 route_list = see discussion below
2140 The contents of the \route_list\ option depend on how many hosts you
2141 are hubbing for, and how their names are related to the domain name.
2142 Suppose the local host is a firewall, and all the domains in
2143 \(*.foo.bar)\ have MX records pointing to it, and each domain
2144 corresponds to a host of the same name. Then the setting could be
2146 ==> route_list = *.foo.bar $domain
2148 If there isn't a convenient relationship between the domain names
2149 and the host names, you either have to list each domain separately,
2150 or use a lookup expansion to look up the host from the domain, or
2151 put the routing information in a file and use the \route_data\
2152 option with a lookup expansion.
2154 (3) If neither (1) nor (2) is the case, the lowest numbered MX record or
2155 the address record for the domain should not be pointing to your
2156 host. You should arrange to get the DNS mended.
2159 Q0302: Why does Exim say \*all relevant MX records point to non-existent hosts*\
2160 when MX records point to IP addresses?
2162 A0302: MX records cannot point to IP addresses. They are defined to point to
2163 host names, so Exim always interprets them that way. (An IP address is a
2164 syntactically valid host name.) The DNS for the domain you are having
2165 problems with is misconfigured.
2167 However, it appears that more and more DNS zones are breaking the rules
2168 and putting IP addresses on the RHS of MX records. Exim follows the
2169 rules and rejects this, but other MTAs do support it, so the
2170 \allow_mx_to_ip\ was regretfully added at release 3.14 to permit this
2174 Q0303: How do I configure Exim to send all messages to a central server? I
2175 don't want to do any local deliveries at all on this host.
2177 A0303: Use this as your first and only router:
2179 ==> send_to_gateway:
2180 driver = manualroute
2181 transport = remote_smtp
2182 route_list = * central.server.host
2185 Q0304: How do I configure Exim to send all non-local mail to a gateway host?
2187 A0304: Replace the \%dnslookup%\ router in the default configuration with the
2190 ==> send_to_gateway:
2191 driver = manualroute
2192 domains = !+local_domains
2193 transport = remote_smtp
2194 route_list = * gate.way.host
2196 If there are several hosts you can send to, you can specify them as a
2197 colon-separated list.
2200 Q0305: How can I arrange for mail on my local network to be delivered directly
2201 to the relevant hosts, but all other mail to be sent to my ISP's mail
2202 server? The local hosts are all DNS-registered and behave like normal
2205 A0305: Set up a first router to pick off all the domains for your local
2206 network. There are several ways you might do this. For example
2210 transport = remote_smtp
2211 domains = *.mydomain.com
2213 This does a perfectly conventional DNS routing operation, but only for
2214 the domains that match \(*.mydomain.com)\. Follow this with a `smart
2218 driver = manualroute
2219 domains = !+local_domains
2220 transport = remote_smtp
2221 route_list = * mail.isp.net
2223 This routes any other non-local domains to the smart host.
2226 Q0306: How do I configure Exim to send all non-local mail to a central server
2227 if it cannot be immediately delivered by my host? I don't want to have
2228 queued mail waiting on my host.
2230 A0306: Add to the \%remote_smtp%\ transport the following:
2232 ==> fallback_hosts = central.server.name(s)
2234 If there are several names, they must be separated by colons.
2237 Q0307: The \route_list\ setting \"^foo$:^bar$ $domain"\ in a \%manualroute%\
2238 router does not work.
2240 A0307: The first thing in a \route_list\ item is a single pattern, not a list of
2241 patterns. You need to write that as \"^(foo|bar)$ $domain"\.
2242 Alternatively, you could use several items and write
2244 ==> route_list = foo $domain; bar $domain
2246 Note the semicolon separator. This is because the second thing in each
2247 item can itself be a colon-separated list of hosts.
2250 Q0308: I have a domain for which some local parts must be delivered locally,
2251 but the remainder are to be treated like any other remote addresses.
2253 A0308: One possible way of doing this is as follows: Assuming you are using a
2254 configuration that is similar to the default one, first exclude your
2255 domain from the first router by changing it to look like this:
2257 ==> non_special_remote:
2259 domains = ! +local_domains : ! special.domain
2260 transport = remote_smtp
2261 ignore_target_hosts = 127.0.0.0/8
2264 Then add a second router to handle the local parts that are not to
2265 be delivered locally:
2269 domains = special.domain
2270 local_parts = ! lsearch;/list/of/special/localparts
2271 transport = remote_smtp
2272 ignore_target_hosts = 127.0.0.0/8
2275 The remaining local parts will fall through to the remaining routers,
2276 which can delivery them locally.
2279 Q0309: How can I configure Exim on a firewall machine so that if mail arrives
2280 addressed to a domain whose MX points to the firewall, it is forwarded
2281 to the internal mail server, without having to have a list of all the
2284 A0309: As your first router, have the standard \%dnslookup%\ router from the
2285 default configuration, with the added option
2289 This will handle all domains whose lowest numbered MX records do not
2290 point to your host. Because of the \no_more\ setting, if it encounters
2291 an unknown domain, routing will fail. However, if it hits a domain whose
2292 lowest numbered MX points to your host, the \self\ option comes into
2293 play, and overrides \no_more\. The \"pass"\ setting causes it to pass
2294 the address on to the next router. (The default causes it to generate an
2297 The only non-local domains that reach the second router are those with
2298 MX records pointing to the local host. Set it up to send them to the
2299 internal mail server like this:
2302 driver = manualroute
2303 domains = ! +local_domains
2304 transport = remote_smtp
2305 route_list = * internal.server
2308 Q0310: If a DNS lookup returns no MX records why doesn't Exim just bin the
2311 A0310: If a DNS lookup returns no MXs, Exim looks for an address record, in
2312 accordance with the rules that are defined in the RFCs. If you want to
2313 break the rules, you can set \mx_domains\ in the \%dnslookup%\ router, but
2314 you will cut yourself off from those sites (and there still seem to be
2315 plenty) who do not set up MX records.
2318 Q0311: When a DNS lookup for MX records fails to complete, why doesn't Exim
2319 send the message to the host defined by the A record?
2321 A0311: The RFCs are quite clear on this. Only if it is known that there are no
2322 MX records is an MTA allowed to make use of the A record. When an MX
2323 lookup fails to complete, Exim does not know whether there are any MX
2324 records or not. There seem to be some name servers (or some
2325 configurations of some name servers) that give a ``server fail'' error when
2326 asked for a non-existent MX record. Exim uses standard resolver calls,
2327 which unfortunately do not distinguish between this case and a timeout,
2328 so all Exim can do is try again later.
2331 Q0312: Is it possible to use a conditional expression for the host item in a
2332 \route_list\ for \%manualroute%\ router? I tried the following, but it
2335 ==> route_list = * ${if match{$header_from:}{\N.*\.usa\.net$\N} \
2336 {<smarthost1>}{<smarthost2>}
2338 A0312: The problem is that the second item in \route_list\ contains white
2339 space, which means that it gets terminated prematurely. To avoid this,
2340 you must put the second item in quotes:
2342 ==> route_list = * "${if match{$header_from:}{\N.*\.usa\.net$\N} \
2343 {<smarthost1>}{<smarthost2>}}"
2346 Q0313: I send all external mail to a smart host, but this means that bad
2347 addresses also get passed to the smart host. Can I avoid this?
2349 A0313: Assuming you have DNS availability, set up a conventional \%dnslookup%\
2350 router to do the routing, but in the \%remote_smtp%\ transport set this:
2352 ==> hosts = your.smart.host
2355 This will override the hosts that the router finds so that everything
2356 goes to the smart host, but any non-existent domains will be failed by
2360 Q0314: I have a really annoying intermittent problem where attempts to mail to
2361 valid sites are rejected with \*unknown mail domain*\. This only happens a
2362 few times a day and there is no particular pattern to the sites it
2363 rejects. If I try to lookup the same domain a few minutes later then it
2366 A0314: This is almost certainly a problem with the DNS resolver or the the
2367 domain's name servers.
2369 (1) Have you linked Exim against the newest DNS resolver library that
2370 comes with Bind? If you are using SunOS4 that may be your problem, as
2371 the resolver that comes with that OS is known to be buggy and to give
2372 intermittent false negatives.
2374 (2) Effects like this are sometimes seen if a domain's name servers get
2375 out of step with each other.
2378 Q0315: I'd like route all mail with addresses that can't be resolved (the DNS
2379 lookup times out) to a relay machine.
2381 A0315: Set \pass_on_timeout\ on your \%dnslookup%\ router, and add below it a
2382 \%manualroute%\ router that routes all relevant domains to the relay.
2385 Q0316: I would like to forward all incoming email for a particular domain to
2386 another host via SMTP. Whereabouts would I configure that?
2388 A0316: Use this as your first router:
2391 driver = manualroute
2392 transport = remote_smtp
2393 route_list = the.particular.domain the.other.host
2395 You will also need to adjust the ACL for incoming SMTP so that this
2396 domain is accepted for relaying. If you are using the default
2397 configuration, there is a domain list called \relay_domains\ that is
2401 Q0317: What I'd like to do is have alternative smart hosts, where the one to be
2402 used is determined by which ISP I'm connected to.
2404 A0317: The simplest way to do this is to arrange for the name of the smart host
2405 du jour to be placed in a file when you connect, say \(/etc/smarthost)\.
2406 Then you can read this file from a \%manualroute%\ router like this:
2409 driver = manualroute
2410 transport = remote_smtp
2411 route_list = * ${readfile{/etc/smarthost}{}}
2413 The second argument of the \"readfile"\ item is a string that replaces
2414 any newline characters in the file (in this case, with nothing).
2415 By keeping the data out of the main configuration file, you avoid having
2416 to HUP the daemon when it changes.
2419 Q0318: Exim won't route to a host with no MX record.
2421 A0318: More than one thing may cause this.
2423 (1) Are you sure there really is no MX record? Sometimes a typo results
2424 in a malformed MX record in the zone file, in which case some name
2425 servers give a SERVFAIL error rather than NXDOMAIN. Exim has to treat
2426 this as a temporary error, so it can't go on to look for address records.
2427 You can check for this state using one of the DNS interrogation commands,
2428 such as \(nslookup)\, \(host)\, or \(dig)\.
2430 (2) Is there a wildcard MX record for \(your)\ domain? Is the
2431 \search_parents\ option on in your \%dnslookup%\ router? If the answer to
2432 both these questions is ``yes'', that is the cause of the problem. When
2433 the DNS resolver fails to find the MX record, it tries adding on your
2434 domain if \search_parents\ is true, and thereby finds your wildcard MX
2435 record. For example:
2437 . There is a wildcard MX record for \(*.a.b.c)\.
2439 . There is a host called \(x.y.z)\ that has an A record and no MX record.
2441 . Somebody on the host \(m.a.b.c)\ domain tries to mail to \(user@x.y.z)\.
2443 . Exim calls the DNS to look for an MX record for \(x.y.z)\.
2445 . The DNS doesn't find any MX record. Because \search_parents\ is true,
2446 it then tries searching the current host's parent domain, so it
2447 looks for \(x.y.z.a.b.c)\ and picks up the wildcard MX record.
2449 Setting \search_parents\ false makes this case work while retaining the
2450 wildcard MX record. However, anybody on the host \(m.a.b.c)\ who mails to
2451 \(user@n.a)\ (expecting it to go to \(user@n.a.b.c)\) now has a problem. The
2452 \widen_domains\ option of the \%dnslookup%\ router may be helpful in this
2456 Q0319: I have some mails on my queues that are sticking around longer than
2457 the retry time indicates they should. They are all getting frozen
2458 because some remote admin has set their MX record to 127.0.0.1.
2460 A0319: The admin in question is an idiot. Exim will always freeze such messages
2461 because they are apparently routed to the local host. To bounce these
2462 messages immediately, set
2464 ==> ignore_target_hosts = 127.0.0.1
2466 on the \%dnslookup%\ router. This causes Exim to completely ignore any hosts
2467 with that IP address. In fact, there are quite a number of IP addresses
2468 that should never be used. Here is a suggested configuration list for
2471 ==> # Don't allow domains whose single MX (or A) record is a
2472 # "special-use IPv4 address", as listed in RFC 3330.
2473 ignore_target_hosts = \
2474 # Hosts on "this network"; RFC 1700 (page 4) states that these
2475 # are only allowed as source addresses
2477 # Private networks, RFC 1918
2478 10.0.0.0/8 : 172.16.0.0/12 : 192.168.0.0/16 : \
2479 # Internet host loopback address, RFC 1700 (page 5)
2481 # "Link local" block
2483 # "TEST-NET" - should not appear on the public Internet
2485 # 6to4 relay anycast addresses, RFC 3068
2487 # Network interconnect device benchmark testing, RFC 2544
2489 # Multicast addresses, RFC 3171
2491 # Reserved for future use, RFC 1700 (page 4)
2495 Q0320: How can I arrange for all mail to \*user@some.domain*\ to be forwarded
2496 to \*user@other.domain*\?
2498 A0320: Put this as your first router:
2502 domains = some.domain
2503 data = ${quote:$local_part}@other.domain
2506 Q0321: How can I tell an Exim router to use only IPv4 or only IPv6 addresses
2507 when it finds both types in the DNS?
2509 A0321: You can do this by making it ignore the addresses you don't want. This
2510 example ignores all IPv6 addresses and all IPv4 addresses in the 127
2513 ==> ignore_target_hosts = <; 0000::0000/0 ; 127.0.0.0/8
2515 To ignore all IPv4 addresses, use
2517 ==> ignore_target_hosts = 0.0.0.0/0
2519 See Q0319 for a general discussion of \ignore_target_hosts\.
2522 Q0322: How can I reroute all messages bound for 192.168.10.0 and 10.0.0.0 to
2523 a specific mail server?
2525 A0322: That is an odd requirement. However, there is an obscure feature in
2526 Exim, originally implemented for packet radio people, that perhaps can
2527 help. Check out the \translate_ip_address\ generic router option.
2531 4. ROUTING FOR LOCAL DELIVERY
2533 Q0401: I need to have any mail for \(virt.dom.ain)\ that doesn't match one of the
2534 aliases in \(/usr/lib/aliases.virt)\ delivered to a particular address, for
2535 example, \(postmaster@virt.dom.ain)\.
2537 A0401: Adding an asterisk to a search type causes Exim to look up ``*'' when the
2538 normal lookup fails. So if your aliasing router is something like this:
2542 domains = virt.dom.ain
2543 data = ${lookup{$local_part}lsearch{/usr/lib/aliases.virt}}
2546 you should change \"lsearch"\ to \"lsearch*"\, and put this in the alias
2549 ==> *: postmaster@virt.dom.ain
2551 This solution has the feature that if there are several unknown
2552 addresses in the same message, only one copy gets sent to the
2553 postmaster, because of Exim's normal de-duplication rules.
2555 NOTE: This solution works only if there is also an entry for \(postmaster)\
2556 in the alias file, ultimately resolving to an address that is not in
2557 \(virt.dom.ain)\. See also Q0434.
2560 Q0402: How do I arrange for all incoming email for \(*@some.domain)\ to go into one
2561 pop3 mail account? The customer doesn't want to add a list of specific
2562 local parts to the system.
2564 A0402: Set up a special transport that writes to the mailbox like this:
2566 ==> special_transport:
2574 The file will be written as the user \"exim"\. Then arrange to route all
2575 mail for that domain to that transport, with a router like this:
2579 domains = some.domain
2580 transport = special_transport
2583 Q0403: How do I configure Exim to send messages for unknown local users to a
2586 A0403: Assuming you are using something like the default configuration, where
2587 local users are processed by the later routers, you should add the
2588 following router at the end:
2591 driver = manualroute
2592 transport = remote_smtp
2593 route_list = * server.host.name
2596 However, you should if possible try to verify that the user is known on
2597 the central server before accepting the message in the first place. This
2598 can be done by making use of Exim's ``call forward'' facility.
2601 Q0404: How can I arrange for messages submitted by (for example) Majordomo to
2602 be handled specially?
2604 A0404: You can use the \condition\ option on a router, with a setting such as
2606 ==> condition = ${if and {{eq {$sender_host_address}{}} \
2607 {eq {$sender_ident}{majordom}}} {yes}{no}}
2609 This first tests for a locally-submitted message, by ensuring there is
2610 no sending host address, and then it checks the identity of the user
2611 that ran the submitting process.
2614 Q0405: On a host that accepts mail for several domains, do I have to use fully
2615 qualified addresses in \(/etc/aliases)\ or do I have to set up an alias
2616 file for each domain?
2618 A0405: You can do it either way. The default aliasing router contains this line:
2620 ==> data = ${lookup{$local_part}lsearch{/etc/aliases}}
2622 which is what does the actual lookup. To make it look up the complete
2623 address instead of just the local part, use
2625 ==> data = ${lookup{$local_part@$domain}lsearch{/etc/aliases}}
2627 If you want to use a separate file for each domain, use
2629 ==> data = ${lookup{$local_part}lsearch{/etc/aliases/$domain}}
2632 Q0406: Some of my users are using the \(.forward)\ to pipe to a shell command which
2633 appends to the user's INBOX. How can I forbid this?
2635 A0406: If you allow your users to run shells in pipes, you cannot control which
2636 commands they run or which files they write to. However, you should point
2637 out to them that writing to an INBOX by arbitrary commands is not
2638 interlocked with the MTA and MUAs, and is liable to mess up the contents
2641 If a user simply wants to choose a specific file for the delivery of
2642 messages, this can be done by putting a file name in a \(.forward)\ file
2643 rather than using a pipe, or by using the \"save"\ command in an Exim
2646 You can set \forbid_pipe\ on the router, but that will prevent them from
2647 running any pipe commands at all. Alternatively, you can restrict which
2648 commands they may run in their pipes by setting the \allow_commands\
2649 and/or \restrict_to_path\ options in the \%address_pipe%\ transport.
2652 Q0407: How can I arrange for a default value when using a query-style lookup
2653 such as LDAP or NIS+ to handle aliases?
2655 A0407: Use a second query in the failure part of the original lookup, like
2658 ==> data = ${lookup ldap\
2659 {ldap://x.y.z/l=yvr?aliasaddress?sub?(&(mail=$local_part@$domain))}\
2663 {ldap://x.y.z/l=yvr?aliasaddress?sub?(&(mail=default@$domain))}}\
2666 Of course, if the default is a fixed value you can just include it
2670 Q0408: If I don't fully qualify the addresses in a virtual domain's alias file
2671 then mail to aliases which also match the local domain get delivered to
2674 A0408: Set the \qualify_preserve_domain\ option on the \%redirect%\ router.
2677 Q0409: I want mail for any local part at certain virtual domains to go
2678 to a single address for each domain.
2680 A0409: One way to do this is
2684 data = ${lookup{$domain}lsearch{/etc/virtual}}
2686 The \(/etc/virtual)\ file contains a list of domains and the addresses to
2687 which their mail should be sent. For example:
2689 ==> domain1: postmaster@some.where.else
2690 domain2: joe@xyz.plc
2692 If the number of domains is large, using a DBM or cdb file would be more
2693 efficient. If the lookup fails to find the domain in the file, the value
2694 of the \data\ option is empty, causing the router to decline.
2697 Q0410: How can I make Exim look in the alias NIS map instead of \(/etc/aliases)\?
2699 A0410: The default configuration does not use NIS (many hosts don't run it).
2700 You need to change this line in the \%system_aliases%\ router:
2702 ==> data = ${lookup{$local_part}lsearch{/etc/aliases}}
2706 ==> data = ${lookup{$local_part}nis{mail.aliases}}
2708 If you want to use \(/etc/aliases)\ as well as NIS, put this router (with
2709 a different name) before or after the default one, depending on which
2710 data source you want to take precedence.
2713 Q0411: Why will Exim deliver a message locally to any username that is longer
2714 than 8 characters as long as the first 8 characters match one of the
2717 A0411: The problem is in your operating system. Exim just calls the \^^getpwnam()^^\
2718 function to test a local part for being a local login name. It does not
2719 presume to guess the maximum length of user name for the underlying
2720 operating system. Many operating systems correctly reject names that are
2721 longer than the maximum length; yours is apparently deficient in this
2722 regard. To cope with such systems, Exim has an option called
2723 \max_user_name_length\ which you can set to the maximum allowed length.
2726 Q0412: Why am I seeing the error \*bad mode (100664) for /home/test/.forward*\?
2727 I've looked through the documentation but can't see anything to suggest
2728 that Exim has to do anything other than read the \(.forward)\ file.
2730 A0412: For security, Exim checks for mode bits that shouldn't be set, by
2731 default 022. You can change this by setting the \modemask\ option of the
2732 \%redirect%\ router that is handling \(.forward)\ files.
2735 Q0413: When a user's \(.forward)\ file is syntactially invalid, Exim defers
2736 delivery of all messages to that user, which sometimes include the
2737 user's own test messages. Can it be told to ignore the \(.forward)\ file
2738 and/or inform the user of the error?
2740 A0413: Setting \skip_syntax_errors\ on the redirect router causes syntax
2741 errors to be skipped. When dealing with users' \(.forward)\ files it is best
2742 to combine this with a setting of \syntax_errors_to\ in order to send
2743 a message about the error to the user. However, to avoid an infinite
2744 cascade of messages, you have to be able to send to an address that
2745 bypasses \(.forward)\ file processing. This can be done by including a
2746 router like this one
2751 transport = local_delivery
2752 local_part_prefix = real-
2754 before the \%redirect%\ router that handles \(.forward)\ files. This will
2755 do an ordinary local delivery without \(.forward)\ processing, if the
2756 local part is prefixed by \"real-"\. You can then set something like
2757 the following options on the \%redirect%\ router:
2759 ==> skip_syntax_errors
2760 syntax_errors_to = real-$local_part@$domain
2761 syntax_errors_text = "\
2762 This is an automatically generated message. An error has been \
2763 found\nin your .forward file. Details of the error are reported \
2764 below. While\nthis error persists, messages addressed to you will \
2765 get delivered into\nyour normal mailbox and you will receive a \
2766 copy of this message for\neach one."
2768 A final tidying setting to go with this is a rewriting rule that changes
2769 \"real-username"\ into just \"username"\ in the headers of the message:
2771 ==> \N^real-([^@]+)@your\.dom\.ain$\N $1@your.dom.ain h
2773 This means that users won't ever see the \"real-"\ prefix, unless they
2774 look at the ::Envelope-To:: header.
2777 Q0414: I have set \caseful_local_part\ on the routers that handle my local
2778 domain because my users have upper case letters in their login names,
2779 but incoming mail now has to use the correct case. Can I relax this
2782 A0414: If you really have to live with caseful user names but want incoming
2783 local parts to be caseless, then you have to maintain a file, indexed by
2784 the lower case forms, that gives the correct case for each login, like
2793 and at the start of the routers that handle your local domain, put one
2796 ==> set_case_router:
2798 data = ${lookup{${lc:$local_part}}lsearch{/the/file}}
2799 qualify_preserve_domain
2801 For efficiency, you should also set the \redirect_router\ option to cause
2802 processing of the changed address to begin at the next router. If you
2803 are otherwise using the default configuration, the setting would be
2805 ==> redirect_router = system_aliases
2807 If there are lots of users, then a DBM or cdb file would be more
2808 efficient than a linear search. If you are handling several domains,
2809 you will have to extend this configuration to cope appropriately.
2812 Q0415: Can I use my existing alias files and forward files as well as procmail
2813 and effectively drop in Exim in place of Sendmail ?
2815 A0415: Yes, as long as your alias and forward files don't assume that pipes are
2816 going to run under a shell. If they do, you either have to change them,
2817 or configure Exim to use a shell (which it doesn't by default).
2820 Q0416: What is quickest way to set up Exim so any message sent to a
2821 non-existing user would bounce back with a different message, based
2822 on the name of non-existing user?
2824 A0416: Place this router last, so that it catches any local addresses that
2825 are not otherwise handled:
2829 transport = non_exist_reply
2832 Then add the following transport to the transports section:
2834 ==> non_exist_reply:
2837 to = $sender_address
2838 subject = User does not exist
2839 text = You sent mail to $local_part. That's not a valid user here. \
2840 The subject was: $subject.
2842 If you want to pick up a message from a file, you can use the \file\
2843 option (use \file_expand\ if you want its contents expanded).
2846 Q0417: What do I need to do to make Exim handle \(/usr/ucb/vacation)\ processing
2847 automatically, so that people could just create a \(.vacation.msg)\ file in
2848 their home directory and not have to edit their \(.forward)\ file?
2850 A0417: Add a new router like this, immediately before the normal \%localuser%\
2856 require_files = $home/.vacation.msg
2857 transport = vacation_transport
2860 and a matching new transport like this:
2862 ==> vacation_transport:
2864 command = /usr/ucb/vacation $local_part
2866 However, some versions of \(/usr/ucb/vacation)\ do not work properly unless
2867 the DBM file(s) it uses are created in advance - it won't create them
2868 itself. You also need a way of removing them when the vacation is over.
2870 Another possibility is to use a fixed filter file which is run whenever
2871 \(.vacation.msg)\ exists, for example:
2876 require_files = $home/.vacation.msg
2877 file = /some/central/filter
2880 The filter file should use the \"if personal"\ check before sending mail,
2881 to avoid generating automatic responses to mailing lists. If sending a
2882 message is all that it does, this doesn't count as a ``significant''
2883 delivery, so the original message goes on to be delivered as normal.
2885 Yet another possibility is to make use of Exim's \%autoreply%\ transport,
2886 and not use \(/usr/ucb/vacation)\ at all.
2889 Q0418: I want to use a default entry in my alias file to handle unknown local
2890 parts, but it picks up the local parts that the aliases generate. For
2891 example, if the alias file is
2893 ==> luke.skywalker: luke
2897 then messages addressed to \/luke.skywalker/\ end up at \/postmaster/\.
2899 A0418: The default mechanism works best with virtual domains, where the
2900 generated address is not in the same domain. If you just want to pick up
2901 all unknown local parts and send them to postmaster, an easier way to do
2902 it is to put this as your last router:
2909 Another possibility is to put the redirect router for these aliases
2910 after all the other routers, so that local parts which are user names
2911 get picked off first. You will need to have two aliasing routers if
2912 there are some local parts (e.g. \/root/\) which are login names, but which
2913 you want to handle as aliases.
2916 Q0419: I have some obsolete domains which people have been warned not to use
2917 any more. How can I arrange to delete any mail that is sent to them?
2919 A0419: To reject them at SMTP time, with a customized error message, place
2920 statments like this in the ACL:
2922 ==> deny message = The domain $domain is obsolete
2923 domains = lsearch;/etc/exim/obsolete.domains
2925 For messages that don't arrive over SMTP, you can use a router like
2926 this to bounce them:
2930 domains = lsearch;/etc/exim/obsolete.domains
2932 data = :fail: the domain $domain is obsolete
2934 If you just want to throw away mail to those domains, accept them at
2935 SMTP time, and use a router like this:
2938 domains = lsearch;/etc/exim/obsolete.domains
2942 Q0420: How can I arrange that mail addressed to \(anything@something.mydomain.com)\
2943 gets delivered to \(something@mydomain.com)\?
2945 A0420: Set up a router like this:
2947 ==> user_from_domain:
2949 data = ${if match{$domain}{\N^(.+)\.mydomain\.com$\N}\
2953 Q0421: I can't get a regular expression to work in a \local_parts\ option on
2956 A0421: Have you remembered to protect any backslash and dollar characters in
2957 your regex from unwanted expansion? The easiest way is to use the
2958 \"@\N"\ facility, like this:
2960 ==> local_parts = \N^0740\d{6}\N
2963 Q0422: How can I arrange for all addresses in a group of domains \(*.example.com)\
2964 to share the same alias file? I have a number of such groups.
2966 A0422: For a single group you could just hard wire the file name into a router
2969 ==> domains = *.example.com
2971 set, to restrict it to the relevant domains. For a number of such groups
2972 you can create a file containing the domains, like this:
2974 ==> *.example1.com example1.com
2975 *.example2.com example2.com
2978 Then create a router like this
2982 domains = partial-lsearch;/that/file
2983 data = ${lookup{$local_part}lsearch*{/etc/aliases.d/$domain_data}}
2985 The variable \$domain_data$\ contains the data that was looked up when the
2986 \domains\ option was matched, i.e. \"example1.com"\, \"example2.com"\, etc.
2990 Q0423: Some of our users have no home directories; the field in the password
2991 file contains \(/no/home/dir)\. This causes the error \*failed to stat
2992 /no/home/dir (No such file or directory)*\ when Exim tries to look for a
2993 \(.forward file)\, and the delivery is deferred.
2995 A0423: There are two issues involved here:
2997 (1) With the default configuration, you are asking Exim to check for a
2998 \(.forward)\ file in the user's home directory. If no file is found,
2999 Exim tries to \^^stat()^^\ the home directory. This is so that it will
3000 notice a missing NFS home directory, and not treat it as if the
3001 \(.forward)\ file did not exist. This \^^stat()^^\ is failing when the
3002 home directory really doesn't exist. You should arrange for the
3003 \%userforward%\ router not to run for these special users, by adding
3006 ==> condition = ${if eq {$home}{/no/home/dir}{no}{yes}}
3008 (2) If you use \check_local_user\ on another router to route to a local
3009 transport (again, this is what is in the default configuration), you
3010 will also have to specify a current directory for the transport, because
3011 by default it makes the home directory current. This is easily done by
3014 ==> current_directory = /
3018 ==> transport_current_directory = /
3020 to the router. Or you can add \home_directory\ to the transport, because
3021 the current directory defaults to the home directory.
3024 Q0424: How can I disable Exim's de-duplication features? I want it to do two
3025 deliveries if two different aliases expand to the same address.
3027 A0424: This is not possible. Duplication has other ramifications other than
3028 just (in)convenience. Consider:
3030 . Message is addressed to A and to B.
3032 . Both A and B are aliased to C.
3034 . Without de-duplication, two deliveries to C are scheduled.
3036 . One delivery happens, Exim records that it has delivered the message
3039 . The next delivery fails (C's mailbox is over quota, say).
3041 Next time round, Exim wants to know if it has already delivered to C or
3042 not, before scheduling a new delivery. Has it? Obviously, if duplicate
3043 deliveries are supported, it has to remember not only that it has
3044 delivered to C but also the ``history'' of how that delivery happened - in
3045 effect an ancestry list back to the original envelope address. This it
3046 does not do, and changing it to work in that way would be a lot of work
3049 The best way to get duplicate deliveries if you want them is not to use
3050 aliases, but to route the addresses directly to a transport, e.g.
3054 local_parts = lsearch;/etc/list/of/special/local/parts
3055 transport = local_delivery
3059 Q0425: My users' mailboxes are distributed between several servers according to
3060 the first letter of the user name. All the servers receive incoming mail
3061 at random. I would like to have the same configuration file for all the
3062 servers, which does local delivery for the mailboxes it holds, and sends
3063 other addresses to the correct other server. Is this possible?
3065 A0425: It is easiest if you arrange for all the users to have password entries
3066 on all the servers. This means that non-existent users can be detected
3067 at the first server they reach. Set up a file containing a mapping from
3068 the first letter of the user names to the servers where their mailboxes
3069 are held. For example:
3076 Before the normal \%localuser%\ router, place the following router:
3079 driver = manualroute
3081 transport = remote_smtp
3082 route_list = * ${lookup{${substr_0_1:$local_part}}lsearch{/etc/mapfile}}
3085 This router checks for a local account, then looks up the host from the
3086 first character of the local part. If the host is not the local host,
3087 the address is routed to the \%remote_smtp%\ transport, and sent to the
3088 correct host. If the host is the local host, the \self\ option causes
3089 the router to pass the address to the next router, which does a local
3092 The router is skipped for local parts that are not the names of local
3093 users, and so these addresses fail.
3096 Q0426: One of the things I want to set up is for \(anything@onedomain)\ to forward
3097 to \(anything@anotherdomain)\. I tried adding \($local_part@anotherdomain)\ to
3098 my aliases but it did not expand - it sent it to that literal address.
3100 A0426: If you want to do it that way, you can use the \"expand"\ operator on
3101 the lookup used in the data option of the redirect router. For example:
3103 ==> data = ${expand:${lookup{$local_part}lsearch*{/etc/aliases}}}
3105 Another approach is to use a router like this:
3110 data = $local_part@anotherdomain
3112 The value of \data\ can, of course, be more complicated, involving
3113 lookups etc. if you have lots of different cases.
3116 Q0427: How can I have an address looked up in two different alias files, and
3117 delivered to all the addresses that are found?
3119 A0427: Use a router like this:
3123 data = ${lookup{$local_part}lsearch{/etc/aliases1}\
3124 {$value${lookup{$local_part}lsearch{/etc/aliases2}{,$value}}}\
3125 {${lookup{$local_part}lsearch{/etc/aliases2}{$value}fail}}}\
3127 If the first lookup succeeds, the result is its data, followed by the
3128 data from the second lookup, if any, separated by a comma. If the first
3129 lookup fails, the result is the data from the third lookup (which also
3130 looks in the second file), but if this also fails, the entire expansion
3131 is forced to fail, thereby causing the router to decline.
3133 Another approach is to use two routers, with the first re-generating the
3134 original local part when it succeeds. This won't get processed by the
3135 same router again. For example:
3139 data = ${lookup{$local_part}lsearch{/etc/aliases1}{$value,$local_part}}
3142 data = ${lookup{$local_part}lsearch{/etc/aliases2}}
3144 This scales more easily to three or more alias files.
3147 Q0428: I've converted from Sendmail, and I notice that Exim doesn't make use
3148 of the \"owner-"\ entries in my alias file to change the sender address in
3149 outgoing messages to a mailing list.
3151 A0428: If you have an alias file with entries like this:
3153 ==> somelist: a@b, c@d, ...
3154 owner-somelist: postmaster
3156 Sendmail assumes that the second entry specifies a new sender address
3157 for the first. Exim does not make this assumption. However, you can make
3158 it take the same action, by adding
3160 ==> errors_to = owner-$local_part@whatever.domain
3162 to the configuration for your aliasing router. This is fail-safe,
3163 because Exim verifies a new sender address before using it. Thus, the
3164 change of sender address occurs only when the owner entry exists.
3167 Q0429: I would like to deliver mail addressed to a given domain to local
3168 mailboxes, but also to generate messages to the envelope senders.
3170 A0429: You can do this with an ``unseen'' router and an \%autoreply%\ transport,
3171 along the following lines:
3177 domains = <domains you want to do this for>
3178 condition = ${if eq{$sender_address}{}{no}{yes}}
3179 transport = warning_t
3183 Place this router immediately before the normal \%localuser%\ router. The
3184 \unseen\ option means that the address is still passed on to the next
3185 router. The transport is configured like this:
3190 file = /usr/local/mail/warning.txt
3192 from = postmaster@your.domain
3193 to = $sender_address
3195 subject = Re: Your mail to $local_part@$domain
3197 Note the use of the \condition\ option to avoid attempting to send a
3198 message when there is no sender (that is, when the incoming message is a
3199 bounce message). You can of course extend this to include other
3200 conditions. If you want to log the sending of messages, you can add
3202 ==> log = /some/file
3204 to the transport and also make use of the \once\ option if you want to
3205 send only one message to each sender.
3208 Q0430: Whenever Exim tries to route a local address, it gives a permission
3209 denied error for the \(.forward)\ file, like this:
3211 ==> 1998-08-10 16:55:32 0z5y2W-0000B8-00 == xxxx@yyy.zzz <xxxx@yyy.zz>
3212 D=userforward defer (-1): failed to open /home/xxxx/.forward
3213 (userforward router): Permission denied (euid=1234 egid=101)
3215 A0430: Have you remembered to make Exim setuid \/root/\?
3218 Q0431: How do I configure Exim to allow arbitrary extensions in local parts, of
3219 the form \/+extension/\?
3221 A0431: Add this pre-condition to the relevant router:
3223 ==> local_part_suffix = +*
3225 If you want the extensions to be optional, also add the option
3227 ==> local_part_suffix_optional
3229 When the router runs, \$local_part$\ contains the local part with the
3230 extension removed, and the extension (if any) is in \$local_part_suffix$\.
3231 If you have set \check_local_user\, the test is carried out after the
3232 extension is removed.
3235 Q0432: I use NIS for my user data. How can I stop Exim rejecting mail when my
3236 NIS servers are being restarted?
3238 A0432: Exim doesn't know that you are using NIS; it just calls the \^^getpwnam()^^\
3239 function, which is routed by nsswitch. Unfortunately, \^^getpwnam()^^\
3240 was never designed to be routed through NIS, and it returns NULL if the
3241 entry is not found or if the connection to the NIS server fails. This
3242 means that Exim cannot tell the difference between ``no such user'' and
3245 Crutches to help with this problem are \finduser_retries\ in Exim, and
3246 \^nscd^\ on the Unix side, but they are not perfect, and mail can still
3247 be lost. However, Nico Erfurth pointed out that you can create a router
3248 for Exim that tests for the availability of NIS, and force a defer if
3253 data = ${lookup {$local_part} nis {passwd}{}}
3255 This should be placed before any router that makes any use of NIS,
3256 typically at the start of your local routers. How does it work? If
3257 your NIS server is reachable, the lookup will take place, and whether it
3258 succeeds or fails, the result is an empty string. This causes the
3259 router to decline, and the address is passed to the following routers.
3260 If your NIS server is down, the lookup defers, and this causes the
3261 router to defer. A verification of an incoming address gets a temporary
3262 rejection, and a delivery is deferred till later.
3265 Q0433: How can I arrange for a single address to be processed by both
3266 \%redirect%\ and \%accept%\?
3268 A0433: Check out the \unseen\ option.
3271 Q0434: How can I redirect all local parts that are not in my system aliases to
3272 a single address? I tried using an asterisk in the system alias file
3273 with an \"lsearch*"\ lookup, but that sent all messages to the
3276 A0434: If your alias file generates addresses in the local domain, they are
3277 also processed as a potential aliases. For example, suppose this is your
3284 The local part \/caesar/\ is aliased to \/jc/\, but that address is then
3285 reprocessed by the routers. As the address is in the local domain, the
3286 alias file is again consulted, and this time the default matches. In
3287 fact after the second aliasing, \/brutus/\ is also processed again from
3288 the start, and is aliased to itself. However, this happens only once,
3289 because the next time, Exim notices that the aliasing router has already
3290 processed \/brutus/\, so the router is skipped in order to avoid
3293 There are several ways of solving this problem; which one you use
3294 depends on your aliasing data.
3296 (1) If the result of aliasing is always a local user name, that is,
3297 aliasing never generates another alias, you can use the
3298 \redirect_router\ option on the router to specify that processing
3299 the generated addresses must start at the next router. For example:
3301 ==> redirect_router = userforward
3303 assuming that the next router is called \%userforward%\. This
3304 ensures that there is at most one pass through the aliasing router.
3306 (2) If you cannot rely on aliases generating non-aliases, it is often
3307 easier not to use a default alias, but instead to place a router
3308 such as the one below after all the other local routers (for the
3314 data = brutus@$domain
3316 Note that the default aliasing technique works more successfully for
3317 virtual domains (see Q0401) because the generated address for the
3318 default is not usually in the same virtual domain as the incoming
3322 Q0435: My alias file contains fully qualified addresses as keys, and some
3323 wildcard domains in the form @foo.bar. Can Exim handle these?
3325 A0435: You can handle fully qualified addresses with this router:
3327 ==> qualified_aliases:
3329 data = ${lookup{$local_part@$domain}lsearch{/etc/aliases}}
3331 (Add any other options you need for the \%redirect%\ router.) Place this
3332 router either before or after the default aliases router that looks up
3333 the local part only. (Or, if you have no unqualified aliases, replace
3334 the default router.)
3336 To handle wildcards in the form @foo.bar you will need yet another
3337 router. (Wildcards of the form *@foo.bar can be handled by an lsearch*@
3338 lookup.) Something like this:
3340 ==> wildcard_aliases:
3342 data = ${lookup{@$domain}lsearch{/etc/aliases}}
3344 Place this after the routers that handle the more specific aliases.
3350 Q0501: My filter isn't working. How can I test it?
3352 A0501: Use the \-bf-\ option (\-bF-\ for a system filter) to test the basic operation
3353 of your filter. You can request debugging information for filtering only
3354 by adding \"-d-all+filter"\ to the command.
3357 Q0502: What I really need is the ability to obtain the result of a pipe
3358 command so that I can filter externally and redirect internally. Is
3361 A0502: The result of a pipe command is not available to a filter, because Exim
3362 does not run any actual deliveries while filtering. It just sets up
3363 deliveries at this time. They all actually happen later. If you want to
3364 run pipes and examine their results, you need to set up a single
3365 delivery to a delivery agent such as \^procmail^\ which provides this kind
3368 An possible alternative is to use the \"${run"\ expansion item to run an
3369 external command while filtering. In this case, you can make use of some
3370 of the results of the command.
3373 Q0503: I received a message with a ::Subject:: line that contained a non-printing
3374 character (a carriage return). This messed up my filter file. Is there a
3375 way to get round it?
3377 A0503: Instead of \"$h_subject:"\ use \"${escape:$h_subject:}"\
3380 Q0504: I want to search for \"$"\ in the subject line, but I can't seem to get
3383 A0504: Try one of these:
3385 ==> if $h_subject: contains \$ then ...
3386 if $h_subject: contains "\\$" then ...
3389 Q0505: My problem is that Exim replaces \$local_part$\ with an empty string in the
3390 system filtering. What's wrong or what did I miss?
3392 A0505: A message may have many recipients. The system filter is run just once
3393 at the start of a delivery attempt. Consequently, it does not make sense
3394 to set \$local_part$\. Which recipient should it be set to? However, you
3395 can access all the recipients from a system filter via the variable
3396 called \$recipients$\.
3399 Q0506: Using \$recipients$\ in a system filter gives me another problem: how can
3400 I do a string lookup if \$recipients$\ is a list of addresses?
3402 A0506: Check out the section of the filter specification called \*Testing a list of
3403 addresses*\. If that doesn't help, you may have to resort to calling an
3404 embedded Perl interpreter - but that is expensive.
3407 Q0507: What are the main differences between using an Exim filter and using
3410 A0507: Exim filters and \^procmail^\ provide different facilities. Exim filters run
3411 at routing time, before any deliveries are done. A filter is like a
3412 ``\(.forward)\ file with conditions''. One of the benefits is de-duplication.
3413 Another is that if you forward, you are forwarding the original message.
3415 However, this does mean that pipes etc. are not run at filtering time,
3416 nor can you change the headers, because the message may have other
3417 recipients and Exim keeps only a single set of headers.
3419 \^procmail^\ runs at delivery time. This is for one recipient only, and so
3420 it can change headers, run pipes and check the results, etc. However, if
3421 it wants to forward, it has to create a new message containing a copy
3422 of the original message.
3424 It's your choice as to which of these you use. You can of course use
3428 Q0508: How can I allow the use of relative paths in users' filter files when
3429 the directories concerned are not available from the password data?
3431 A0508: You need to be running Exim 4.11 or later. You can then specify a value
3432 for \$home$\ by setting the router_home_directory option on the
3433 \%redirect%\ router.
3435 For earlier releases, there is no way to specify the value of \$home$\
3436 for a \%redirect%\ router; it either comes from the password data as a
3437 result of \check_local_user\, or is unset.
3440 Q0509: How can I set up a filter file to detect and block virus attachments?
3442 A0509: Exim's filter facilities aren't powerful enough to do much more than
3443 very crude testing. Most people that want virus checking are nowadays
3444 using one of the separate scanning programs such as \^exiscan^\ (see
3445 \?http://duncanthrax.net/exiscan/?\). There is some further information
3446 about scanning with Exim via \?http://www.timj.co.uk/linux/exim.php?\.
3449 Q0510: Is it possible to write code for scanning messages in Python?
3451 A0510: \^elspy^\ is a layer of glue code that enables you to write Python code
3452 to scan email messages at SMTP time. \^elspy^\ also includes a small
3453 Python library with common mail-scanning tools, including an interface
3454 to SpamAssassin and a simple but effective virus detector. You can
3455 optain \^elspy^\ from \?http://elspy.sourceforge.net/?\.
3458 Q0511: Whenever my system filter uses a \mail\ command to send a message, I get
3459 the error \*User 0 set for address_reply transport is on the never_users
3460 list*\. What does this mean?
3462 A0511: The system filter runs as \/root/\ in Exim 4, unless you set
3463 \system_filter_user\ to specify otherwise. When you set up a delivery
3464 direct from a system filter (an autoreply is a special kind of
3465 ``delivery'') the transport runs as the same user, unless it has a
3466 \user\ setting of its own. Normally, deliveries are not allowed to run
3467 as \/root/\ as a security precaution; this is implemented by the
3468 \never_users\ option (see Q0039).
3470 The easiest solution is to add this to your configuration:
3472 ==> system_filter_user = exim
3474 The system filter then runs as \/exim/\ instead of \/root/\.
3475 Alternatively, you can arrange for autoreplies from the system filter to
3476 use a special transport of their own, and set the \user\ option on that
3480 Q0512: I'm trying to reference the ::Envelope-To:: header in my filter, but
3481 \$h_envelope-to:$\ is always empty.
3483 A0512: ::Envelope-To:: is added at delivery time, by the transport. Therefore,
3484 the header doesn't exist at filter time. In a user filter, the values
3485 you probably want are in \$original_local_part$\ and
3486 \$original_domain$\. In a system filter, the complete list of all
3487 envelope recipients is in \$recipients$\.
3490 Q0513: I want my system filter to freeze all mails greater than 500K in size,
3491 but to exclude those to a specific domain. However, I don't seem to be
3492 able to use \$domain$\ in a system filter.
3494 A0513: You cannot do this in a system filter, because a single message may have
3495 multiple recipients, some in the special domain, and some not. That is
3496 also the reason why \$domain$\ is not set in a system filter.
3498 If you want to take actions on a per-recipient basis, you have to do it
3499 in a router. However, freezing is not appropriate, because freezing
3500 stops all deliveries. You could, however, delay delivery to all but the
3501 special domains by using something like this:
3503 ==> delay_if_too_big:
3505 domains = !the.special.domain
3506 condition = ${if >{$message_size}{500K}{yes}{no}}
3508 data = :defer: message too big.
3510 However, there isn't an easy way of ``releasing'' such messages at
3514 Q0514: When I try to send to two addresses I get an error in the filter
3515 file \*malformed address: , e@fgh.com may not follow a@bcd.com*\. What
3520 ==> deliver "a@bcd.com, e@fgh.com"
3522 in your filter? If so, that is your problem. You should have
3524 ==> deliver a@bcd.com
3527 Each \deliver\ command expects just one address.
3533 Q0601: What does the error \*Neither the xxx router nor the yyy transport set
3534 a uid for local delivery of...*\ mean?
3536 A0601: Whenever Exim does a local delivery, it runs a process under a specific
3537 user and group id (uid and gid). For deliveries into mailboxes, and to
3538 pipes and files set up by forwarding, it normally picks up the uid/gid
3539 of the receiving user. However, if an address is directed to a pipe or a
3540 file by some other means, such an entry in the system alias file of the
3543 ==> majordomo: |/local/mail/majordomo ...
3545 then Exim has to be told what uid/gid to use for the delivery. This can
3546 be done either on the routerr that handles the address, or on the
3547 transport that actually does the delivery. If a pipe is going to run a
3548 setuid program, then it doesn't matter what uid Exim starts it out with,
3549 and so the most straightforward thing is to put
3553 on either the router or the transport. A setting on the transport
3554 overrides a setting on the router, so if the same transport is being
3555 used with several routers, you should set the user on it only if you
3556 want the same uid to be used in all cases.
3558 In the default configuration, the transports used for file and pipe
3559 deliveries are the ones called \address_file\ and \address_pipe\. You
3560 can specify different transports by setting, for example,
3562 ==> pipe_transport = special_pipe_transport
3564 on the \%system_aliases%\ router. Then you can set up \%special_pipe_transport%\
3566 ==> special_pipe_transport:
3570 which will be used only for pipe deliveries from that one router.
3571 What you put for the ???? is up to you, and depends on the particular
3575 Q0602: Exim keeps crashing with segmentation errors (signal 11 or 139) during
3576 delivery. This seems to happen when it is about to contact a remote
3577 host or when a delivery is deferred.
3579 A0602: This could be a problem with Exim's databases. Try running a delivery
3580 with debugging turned on. If the last line of the debug output is
3581 something like this:
3583 ==> locked /var/spool/exim/db/retry.lockfile
3585 the crash is happening inside the DBM library. Check that your DBM
3586 library is correctly installed. In particular, if you have installed a
3587 second DBM library onto a system that already had one, check that its
3588 version of \(ndbm.h)\ is being seen first. For example, if the new
3589 version is in \(/usr/local/include)\, check that there isn't another
3590 version in \(/usr/include)\. If you are using Berkeley db, you can set
3594 in your \(Local/Makefile)\ to avoid using \(ndbm.h)\ altogether. This is
3595 particularly relevant for version 2 (or later) of Berkeley db, because
3596 no \(ndbm.h)\ file is distributed with it. Another thing you can try is
3599 ==> exim_dumpdb /var/spool/exim retry
3601 to see if it also crashes, or build the \^test_dbfn^\ tool and fiddle
3602 around with it. If both fail, it is most almost certainly a problem with
3603 your DBM library. You could try to update it, or force Exim to use
3604 another library. See the file \(doc/dbm.discuss.txt)\ for hints about
3608 Q0603: How can mails that are being routed through routers that do not set
3609 \check_local_user\ be delivered under the uid of the recipient?
3611 A0603: Q0601 contains background information on this. If you are using, say, an
3612 alias file to direct messages to specific mailboxes, you can use
3613 the \user\ option on either the router or the transport to set the uid.
3614 What you put in the setting depends on how the required uid is to be
3615 found. It could be looked up in a file or computed somehow from the
3616 local part, for example.
3619 Q0604: I want to use MMDF-style mailboxes. How can I get Exim to append the
3620 ctrl-A characters that separate indvidual emails?
3622 A0604: Set the \message_suffix\ option in the \%appendfile%\ transport. In fact,
3623 for MMDF mailboxes you need a prefix as well as a suffix to get it
3624 working right, so your transport should contain these settings:
3626 ==> message_prefix = "\1\1\1\1\n"
3627 message_suffix = "\1\1\1\1\n"
3629 Also, you need to change the \check_string\ and \escape_string\ settings so
3630 that the escaping happens for lines in the message that happen to begin
3631 with the MMDF prefix or suffix string, rather than ``From'' (the default):
3633 ==> check_string = "\1\1\1\1\n"
3634 escape_string = "\1\1\1\1 \n"
3636 Adding a space to the line is sufficient to prevent it being taken as a
3640 Q0605: If a user's mailbox is over quota, is there a way for me to set it up so
3641 that the mail bounces to the sender and is not stored in the mail queue?
3643 A0605: In the retry section of the configuration, put
3645 ==> *@your.dom.ain quota
3647 That is, provide no retry timings for over quota errors. They will then
3648 bounce immediately. Alternatively, you can set up retries for a short
3649 time only, or use something like this:
3651 ==> *@your.dom.ain quota_7d
3652 *@your.dom.ain quota F,2h,15m; F,3d,1h
3654 which bounces immediately if the user's mailbox hasn't been read for 7
3655 days, but otherwise tries for up to 3 days after the first quota
3659 Q0606: I'm using tmail to do local deliveries, but when I turned on the
3660 \use_crlf\ option on the \%pipe%\ transport (tmail prefers \"@\r@\n"\
3661 terminations) message bodies started to vanish.
3663 A0606: You need to unset the \mesage_prefix\ option, or change it so that its
3664 default \"@\n"\ terminator becomes \"@\r@\n"\. For example, the
3667 ==> local_delivery_mbx:
3669 command = /usr/local/bin/tmail $local_part
3671 current_directory = /
3675 The reason for this is as follows: tmail uses the line terminator on
3676 the first line it sees to determine whether lines are terminated by
3677 \"@\r@\n"\ or \"@\n"\. If the latter, it moans to stderr and changes subsequent
3678 \"@\n"\ terminators to \"@\r@\n"\. The default setting of the \message_prefix\
3679 option is \"From ...@\n"\, and this is unaffected by the \use_crlf\ option.
3680 If you don't change this, tmail sees the first line terminated by
3681 \"@\n"\ and prepends \"@\r"\ to the \"@\n"\ terminator on all subsequent
3682 lines. However, if \use_crlf\ is set, Exim makes all other lines
3683 \"@\r@\n"\ terminated, leading to doubled \"@\r@\r@\n"\ lines and
3684 corrupt mbx mailboxes.
3687 Q0607: When I activate ``return receipt'' for example in Netscape Mailbox
3688 sending options, then I get an error message from Exim... something
3689 like \*not supported*\. Can I activate delivery confirmations?
3691 A0607: Exim does not support any kind of delivery notification.
3693 (1) You can configure it to recognize headers such as
3694 \Return-receipt-to:\ if you wish.
3696 (2) Some people want MSN (message status notification). Such services
3697 are implemented in MUAs, and don't impact on the MTA at all.
3699 (3) I investigated the RFCs which describe the DSN (delivery status
3700 notification) system. However, I was unable to specify any sensible way
3701 of actually doing anything with the data. There were comments on the
3702 mailing list at the time; many people, including me, conclude that DSN
3703 is in practice unworkable. The killer problem is with forwarding and
3704 aliasing. Do you propagate the DSN data with the generated addresses?
3705 Do you send back a ``reached end of the DSN world'' or ``expanded'' message?
3706 Do you do this differently for different kinds of aliasing/forwarding?
3707 For a user who has a \(.forward)\ file with a single address in, this
3708 might seem easy - just propagate the data. But what if there are several
3709 forwardings? If you propagate the DSN data, the sender may get back
3710 several DSN messages - and should the sender really know about the
3711 detail of the receiver's forwarding arrangements? There isn't really
3712 any way to distinguish between a \(.forward)\ file that is forwarding
3713 and one that is a mini mailing list. And so on, and so on. There are so
3714 many questions that don't have obvious answers.
3717 Q0608: What does the message \*retry time not reached [for any host]*\ on the log
3718 mean? Why won't Exim try to deliver the message?
3720 A0608: That is not an error. It means exactly what it says. A previous attempt
3721 to deliver to that address failed with a temporary error, and Exim
3722 computed the earliest time at which to try again. This can apply to
3723 local as well as to remote deliveries. For remote deliveries, each host
3724 (if there are several) has its own retry time.
3726 If you are running on a dial-up host, the rest of this answer probably
3727 does not apply to you. Go and read Q1404 instead. If your host is
3728 permanently online, read on...
3730 Some MTAs have a retrying schedule for each message. Exim does not work
3731 like this. Retry timing is normally host-based for remote deliveries and
3732 address-based for local deliveries. (There are some exceptions for certain
3733 kinds of remote failure - see \*Errors in outgoing SMTP*\ in the manual.)
3735 If a new message arrives for a failing address and the retry time has
3736 not yet arrived, Exim will log \*retry time not reached*\ and leave the
3737 message on the queue, without attempting delivery. Similarly, if a queue
3738 runner notices the message before the time to retry has arrived, it
3739 writes the same log entry. When the retry time has past, Exim attempts
3740 delivery at the next queue run. If you want to know when that will be,
3741 run the exinext utility on the address, for example:
3743 ==> exinext user@some.domain
3745 You can suppress these messages on the log by including \"-retry_defer"\
3746 in the setting of \log_selector\. You can force a delivery attempt on a
3747 specific message (overriding the retry time) by means of the -M option:
3749 ==> exim -M 10hCET-0000Bf-00
3751 If you want to do this for the entire queue, use the \-qf-\ option.
3754 Q0609: Exim seems to be sending the same message twice, according to the log,
3755 although there is a difference in capitalization of the local part of
3758 A0609: That is correct. The RFCs are explicit in stating that capitalization
3759 matters for local parts. For remote domains, Exim is not entitled to
3760 assume case independence of local parts. I know, it is utterly silly,
3761 and it causes a lot of grief, but that's what the rules say. Here is a
3762 quote from RFC 2821:
3764 ... a command verb, an argument value other than a mailbox local-part,
3765 and free form text MAY be encoded in upper case, lower case, or any
3766 mixture of upper and lower case with no impact on its meaning. This
3767 is NOT true of a mailbox local-part. The local-part of a mailbox
3768 MUST BE treated as case sensitive. Therefore, SMTP implementations
3769 MUST take care to preserve the case of mailbox local-parts. Mailbox
3770 domains are not case sensitive. In particular, for some hosts the
3771 user "smith" is different from the user "Smith". However, exploiting
3772 the case sensitivity of mailbox local-parts impedes interoperability
3776 Q0610: How can I force the next retry time for a host to be now?
3778 A0610: You can change the retry time with the \^exim_fixdb^\ utility, but its
3779 interface is very clumsy. If you have a message for the host on the
3780 queue, the simplest thing to do is to force a delivery with the \-M-\
3781 command line option. If delivery succeeds, the retry data will get
3782 cleared. If the host is past the cutoff time, so that messages are
3783 bouncing immediately without trying a delivery, you can use \-odq-\ to
3784 put a message on the queue without a delivery attempt, and then use
3788 Q0611: I set up \"|/bin/grep Subject|/usr/bin/smbclient -M <netbiosname>"\ as an
3789 alias but it doesn't work.
3791 A0611: That is a shell command line. Exim does not run pipe commands under a
3792 shell by default (for added security - and it saves a process). You
3795 ==> "|/bin/sh -c '/bin/grep Subject|/usr/bin/smbclient -M <netbiosname>'"
3798 Q0612: Why does the \%pipe%\ transport add a line starting with \">From"\ to
3801 A0612: Actually, it adds a line starting with \"From"\ followed by a space.
3802 This is commonly referred to as the \"From_"\ line, to emphasize the
3803 fact that \"From"\ is followed by a space and not a colon. This is a
3804 pseudo-header line that contains the envelope sender address and the
3805 time of delivery. It originated as a separator line in Berkeley format
3806 mailboxes, but is also used in other contexts. (And yes, it is often
3807 confused with the ::From:: header line, and this causes a lot of grief.
3808 The use of \"From_"\ was one of the really bad email design decisions.)
3810 Exim's \%pipe%\ transport adds this pseudo-header line by default
3811 because \(/usr/ucb/vacation)\ needs it, and that is one of the the most
3812 common uses of piping. The \^procmail^\ local delivery agent also makes
3813 use of the \"From_"\ line. If you do not want it, change the setting of
3814 \message_prefix\ on the \%pipe%\ transport. For example, to remove the
3815 line altogether, use
3817 ==> message_prefix =
3819 If you are not piping to \(/usr/ucb/vacation)\ or \^procmail^\, it is
3820 likely that you do not need a \"From_"\ line, and indeed it may cause
3821 problems if it is present.
3823 One user reported that this line gave trouble when a pipe was used to
3824 send messages to Courier's \^deliverquota^\ program. The line was
3825 retained with the message, and caused problems for MS Exchange 2000 when
3826 retrieving messages with its built-in POP collector. Specifically, it
3827 caused Exchange to not be able to recognise message attachments.
3830 Q0613: I have set \fallback_hosts\ on my \%smtp%\ transport, but after the error
3831 \*sem@chat.ru cannot be resolved at this time*\ Exim isn't using them.
3833 A0613: \fallback_hosts\ works only if an attempt at delivery to the original
3834 host(s) fails. In this case, Exim couldn't even resolve the domain
3835 \(chat.ru)\ to discover what the original hosts were, so it never got as far
3836 as the transport. However, see Q0315 for a possible solution.
3839 Q0614: After the holidays my ISP has always hundreds of e-mails waiting for me.
3840 These are forced down Exim's throat in one go. Exim spawns a lot of
3841 kids, but is there some limit to the number of processes it creates?
3843 A0614: Unless you have changed \smtp_accept_queue_per_connection\ it should
3844 spawn only that many processes per connection (default 10). Your ISP
3845 may be making many connections, of course. That is limited by
3849 Q0615: When a message in the queue got to 12h old, Exim wrote \*retry timeout
3850 exceeded*\ and removed all messages in the queue to this host - even
3851 recent messages. How I can avoid this behaviour? I only want to remove
3852 messages that have exceeded the maximum retry time.
3854 A0615: Exim's retrying is host-based rather than message-based. The philosophy
3855 is that if a host has been down for a very long time, there is no point
3856 in keeping messages hanging around. However, you might like to check
3857 out \delay_after_cutoff\ in the \%smtp%\ transport. It doesn't do what you
3858 want, but it might help.
3861 Q0616: Can Exim add a ::Content-Length:: header to messages it delivers?
3863 A0616: You could include something like
3865 ==> headers_remove = "content-length"
3866 headers_add = "Content-Length: $message_body_size"
3868 to the \%appendfile%\ transport. However, the use of ::Content-Length:: can
3869 cause several problems, and is not recommended unless you really know
3870 what you are doing. There is a discussion of the problems in
3871 \?http://home.netscape.com/eng/mozilla/2.0/relnotes/demo/content-length.html?\.
3874 Q0617: Exim seems to be trying to deliver a message every 10 minutes, though
3875 the retry rules specify longer times after a while, because it is
3876 writing a log entry every time, like this:
3878 ==> 1999-08-26 14:51:19 11IVsE-000MuP-00 == example@example.com T=smtp defer
3879 (-34): some host address lookups failed and retry time not reached for
3880 other hosts or connection limit reached
3882 A0617: It is looking at the message every 10 minutes, but it isn't actually
3883 trying to deliver. It's looking up \(example.com)\ in the DNS and finding
3886 ==> example.com. MX 10 example-com.isp.example.com.
3887 example.com. MX 0 mail.example.com.
3888 mail.example.com. A 202.77.183.45
3889 A lookup for example-com.isp.example.com. yielded NXDOMAIN
3891 The last line means that there is no address (A) record in the DNS for
3892 \(example-com.isp.example.com)\. That accounts for \*some host address
3893 lookups failed*\, but the retry time for \(mail.example.com)\ hasn't been
3894 reached, which accounts for \*retry time not reached for other hosts*\.
3897 Q0618: I am trying to set exim up to have a automatic failover if it sees that
3898 the system that it is sending all mail to is down.
3900 A0618: Add to the \%remote_smtp%\ transport the following:
3902 ==> fallback_hosts = failover.server.name(s)
3904 If there are several names, they must be separated by colons.
3907 Q0619: I can't get Exim to deliver over NFS. I get the error \*fcntl() failed:
3908 No locks available*\, though the lock daemon is running on the NFS server
3909 and other hosts are able to access it.
3911 A0619: Check that you have \(lockd)\ running on the NFS client. This is not
3912 always running by default on some systems (Red Hat is believed to be one
3916 Q0620: Why does Exim bounce messages without even attempting delivery, giving
3917 the error \*retry time not reached for any host after a long failure
3920 A0620: This message means that all hosts to which the message could be sent
3921 have been failing for so long that the end of the retry period
3922 (typically 4 or 5 days) has been reached. In this situation, Exim still
3923 computes a next time to retry, but any messages that arrive in the
3924 meantime are bounced straight away. You can alter this behaviour by
3925 unsetting the \delay_after_cutoff\ option on the smtp transport. Then Exim
3926 will try most messages for those hosts once before giving up.
3929 Q0621: My \(.forward)\ file is \"|/usr/bin/procmail -f-"\ and mail gets delivered,
3930 but there was a bounce to the sender, sending him the output of procmail.
3931 How can I prevent this?
3933 A0621: Exim's default configuration is set up like this:
3939 The \return_output\ option requests that any output that the pipe
3940 produces be returned to the sender. That is the safest default. If you
3941 don't want this, you can either remove the option altogether, or change
3942 it to \return_fail_output\, to return output only if the command fails.
3943 Note that this will affect all pipes that users run, not just your
3944 procmail one. It might be better to arrange for procmail not to produce
3945 any output when it succeeds.
3948 Q0622: Can I write an ordinary file when I run a perl script as a transport
3949 filter for the \%remote_smtp%\ and \%address_pipe%\ transports?
3951 A0622: Yes, provided the file is writeable by the uid under which the transport
3952 runs (the Exim user in the case of the remote transport). However, if two
3953 messages are being delivered at once, their data will get mixed up in
3954 the file unless you implement your own locking scheme. If all you want
3955 to do is to take a copy of the message, another approach that avoids
3956 the locking problem is to use a system filter to set up an ``unseen''
3957 delivery to a file. If you only want the message's headers, you can
3958 set \message_filter_file_transport\ to point to a special \%appendfile%\
3959 transport that has \headers_only\ set.
3962 Q0623: My \(/var/spool/mail)\ has grown drastically. Is there any possibility of
3963 using two directories?
3965 A0623: You can use an expansion string to split mailboxes between two
3966 directories. For example,
3968 ==> file = /var/spool/mail${nhash_2:$local_part}/$local_part
3970 which does a hash on the local part, producing either 0 or 1, thereby
3971 using \(mail0) or \(mail1)\. But remember, the MUAs that read these mailboxes
3972 also have to know where they are.
3975 Q0624: Sendmail has a program called \^smrsh^\ that restricts what binaries
3976 can be run from sendmail aliases. Is there something like this in Exim ?
3978 A0624: Check out the \allow_commands\ option in the \%pipe%\ transport.
3981 Q0625: I wish to have large emails go out one at a time.
3983 A0625: One possibility is to set up a router that defers all large messages,
3984 except in queue runs. Since queue runners deliver just one
3985 message at a time, if you limited the number of simultaneous queue
3986 runners to 1, you would get the effect you wanted. A suitable router
3989 ==> defer_if_large_unless_queue_run:
3991 condition = ${if or{{queue_running}{<{$message_size}{200K}}}{no}{yes}}
3993 data = :defer: too large for immediate delivery
3996 Of course, this would always delay any large message until the next
3997 queue runner, but if you run them fairly regularly, this shouldn't be a
3998 huge problem, and may even be desirable. Note the use of \no_verify\ to
3999 ensure that this router is not used when Exim is verifying addresses.
4002 Q0626: Exim can route local parts independent of their case, but the Cyrus LMTP
4003 daemon requires the correct case. How can I fix this?
4005 A0626: You need to rewrite the local part to the correct case before running
4006 the router that routes to Cyrus. For example, if you require all lower
4007 case, and your router is called \local_user\, put this router in front
4010 ==> lowercase_local:
4012 redirect_router = local_user
4013 domains = +local_domains
4014 data = ${lc:$local_part}@$domain
4016 The setting of \redirect_router\ causes processing of the rewritten
4017 address to start at the next router, instead of the first router. See
4018 also Q0630 and Q0414, and see C045 for a more complete Cyrus
4022 Q0627: Is there a command I can send to Exim to retry all queued messages
4023 regardless of their retry schedule?
4025 A0627: The \-qff-\ option starts a queue runner that forces a delivery attempt
4026 for all messages, including frozen ones. If you use \-qf-\, frozen
4027 messages are skipped.
4030 Q0628: I have the default retry rule, which I thought meant that Exim should
4031 keep trying for four days, but it seems to be bouncing some messages
4034 A0628: See Q0615 and Q0620.
4037 Q0629: I'm having trouble with quotas and Courier, because Exim is not handling
4040 A0629: You must be using an old version of Exim; it has supported maildirsize
4041 files since release 4.30.
4044 Q0630: How can I configure Exim to deliver to a Cyrus message store?
4046 A0630: (1) The reference manual contains an example that uses pipe delivery.
4048 (2) Here is a transport that uses LMTP delivery, assuming that
4049 \$local_part$\ contains the username:
4054 socket = /var/cyrus/socket/lmtp
4056 (3) This is a transport that delivers direct to a non-inbox mailbox:
4065 command = "/usr/cyrus/bin/deliver -a $local_part \
4066 -m <mailbox-name> $local_part"
4068 This delivers to the Cyrus mailbox \"user.$local_part.<mailbox-name>"\.
4069 Using \"user = $local_part"\ and \"-a $local_part"\ makes it work
4070 without needing an explicit `p' ACL set for `anyone' on the mailbox.
4073 Q0631: I would like to choose a retry rule based on on the sender rather than
4074 the recipient address. Is this possible?
4076 A0631: Yes. In release 4.43 and later releases, you can do this directly by
4077 adding a third item to a retry rule of the form "senders=<address
4078 list>". The retry timings themselves then become the fourth item. For
4081 ==> * * senders=: F,1h,30m
4083 would match all bounce messages. If the address list contains white
4084 space, it must be enclosed in quotes. For example:
4086 ==> a.domain timeout senders="x@b.dom : y@c.dom" G,8h,10m,1.5
4088 If you are using an earlier release of Exim, you can still achieve the
4089 effect, but in a more complicated way. The address part of a retry rule
4090 is matched as a single-item address list. Such lists are always
4091 expanded, so you can use something like this:
4093 ==> "${if eq{$sender_address}{xxx}{*@*}{no@no}}" quota F,1h,10m; ...
4095 If the sender address is ``xxx'', the pattern expands to ``*@*'', which
4096 matches all recipient addresses; if you want to, you can make this a
4097 more restrictive pattern. If the sender address is not ``xxx'', the
4098 pattern expands to ``no@no'', which is assumed to be a recipient address
4099 that can never match, so the retry rule is skipped.
4102 Q0632: What does the error \*User 1 set for local_mbx_delivery transport is on
4103 the never_users list*\ mean?
4105 A0632: You have configured the \%local_mbx_delivery%\ to run as the user whose
4106 id (uid) is 1. However, this user is on the list defined by the
4107 \never_users\ runtime option, or the \\FIXED_NEVER_USERS\\ compile-time
4108 option. These are ``safety catch'' lists; Exim refuses to deliver to any
4109 user that is on them. The most common use of \never_users\ is to avoid
4110 doing any deliveries as \/root/\, but it can contain other uids.
4113 Q0633: Why is \$domain$\ not set in the \%smtp%\ transport?
4115 A0633: The \%smtp%\ transport can handle several recipient addresses at once.
4116 This happens by default if the host lists for the addresses are
4117 identical. A single copy of the message is sent, using multiple \\RCPT\\
4118 commands to transmit multiple envelope recipients. The \$domain$\
4119 variable is set in the \%smtp%\ transport only if all the recipient
4120 addresses have the same domain. You must have a case where several
4121 addresses with different domains resolve to the same set of hosts.
4123 If you want to restrict the transport so that it handles only a single
4124 domain at once (but still possibly with more than one recipient), set
4126 ==> multi_domain = false
4128 If you want to restrict the transport so that it handles only a single
4129 address at once, set
4134 Q0634: How can I stop a local transport from trying to access the user's home
4135 directory, even when the delivery is to a file that is elsewhere?
4137 A0634: See answer (2) for Q0423.
4140 Q0635: The log message \*error ignored*\ appears after some delivery failures.
4143 A0635: This message is written when Exim fails to deliver a bounce message whose
4144 age is greater than \ignore_bounce_errors_after\. It indicates that the
4145 failing bounce message has been discarded.
4147 The same message is written after failed deliveries when a filter file
4148 uses the \noerror\ feature when setting up a delivery, or if a router
4153 Both of these specify that delivery failures are to be discarded.
4159 Q0701: How do I block unwanted messages from outside my host?
4161 A0701: Exim uses Access Control Lists (ACLs) for controlling incoming mail from
4162 other hosts. A whole chapter in the reference manual is devoted to
4163 describing how they work. A wide variety of conditions can be imposed on
4166 The default Exim run time configuration contains an example of an ACL
4167 which blocks all relaying, and messages whose senders cannot be
4168 verified. This example is heavily commented and worth studying.
4171 Q0702: I don't want to block spam entirely; how can I inspect each message
4172 before deciding whether or not to deliver it?
4174 A0702: Wherever possible, inspection and rejection is best done automatically
4175 in an ACL, that is, before the message is accepted. If you want to
4176 verify manually each message that is classified as spam by an automatic
4177 check, you can arrange for a system filter to freeze such messages after
4178 they have been accepted.
4180 If, after inspection, you decide not to deliver the message, it is
4181 safest to discard it, using the \-Mrm-\ option. Use of the \-Mg-\ option
4182 to force a bounce carries the risk of ``collateral spam'' if the sender
4183 address is faked (as it usually is in spam).
4186 Q0703: How can I test that my spam blocks are working?
4188 A0703: The \-bh-\ option allows you to run a testing SMTP session as if from a
4189 given IP address. For example,
4191 ==> exim -bh 192.168.178.39
4193 In addition to the normal SMTP replies, it outputs commentary about
4194 which tests have succeeded or failed. If you are not interested in the
4195 details, but just want to know if a particular sender at a particular IP
4196 address is able to mail to a particular recipient, you can use the
4197 \exim_checkaccess\ utility, which provides a ``packaged'' version of
4198 \-bh-\. You call it like this:
4200 ==> exim_checkaccess 192.168.53.23 recip@my.domain -f sender@some.domain
4202 If you don't give a sender, \"<>"\ is used (that it, it acts like a
4206 Q0704: How can I test that Exim is correctly configured to use a DNS black list
4207 such as the Realtime Blackhole List (RBL)?
4209 A0704: The \-bh-\ option allows you to run a testing SMTP session as if from a
4210 given address. The \^exim_checkaccess^\ utility provides a more packaged
4211 version of this facility. You need to know a blocked IP address with
4212 which to test. Such a testing address is kindly provided by Russell
4215 ==> linux.crynwr.com [192.203.178.39]
4217 You can also send mail to \(nelson@linux.crynwr.com)\ from the server
4218 whose RBL block you are testing. The robot that receives that email
4219 will attempt to send a piece of test email in reply. If your RBL block
4220 didn't work, you get a message to that effect. Regardless of whether the
4221 RBL block succeeds or not, it emails you the results of the SMTP
4222 conversation from a host that is not on the RBL, so you can see how your
4223 server looks from the view of someone on the RBL.
4226 Q0705: How can I use tcpwrappers in conjunction with Exim?
4228 A0705: Exim's own control facilities can do all that tcpwrappers can do.
4229 However, if you are already using tcpwrappers for other things it might
4230 be convenient to include Exim controls in the same place.
4232 First of all, ensure that Exim is built to call the tcpwrappers library,
4233 by including \\USE_TCPWRAPPERS=yes\\ in \(Local/Makefile)\. You also need to
4234 ensure that the header file \(tcpd.h)\ is available at compile time, and the
4235 \(libwrap.a)\ library is available at link time, typically by including it in
4236 \\EXTRALIBS\\. You may need to copy these two files from the tcpwrappers
4237 build directory to, for example, \(/usr/local/include)\ and \(/usr/local/lib)\,
4238 respectively. Then you could reference them by
4240 ==> CFLAGS=-I/usr/local/include
4241 EXTRALIBS=-L/usr/local/lib -lwrap
4243 in \(Local/Makefile)\. There are two ways to make use of the functionality,
4244 depending on how you have tcpwrappers set up. If you have it set up to
4245 use only one file, you ought to have something like:
4247 ==> /etc/hosts.allow:
4249 ==> exim : <client_list> : <allow_or_deny>
4253 ==> exim : LOCAL 192.168.0. .friendly.domain special.host : ALLOW
4256 This allows connections from local hosts (chiefly //localhost//), from
4257 the subnet 192.168.0.0/24, from all hosts in \(*.friendly.domain)\, and
4258 from a specific host called \(special.host)\. All other connections are
4259 denied. If you have tcpwrappers set up to use two files, use the
4262 ==> /etc/hosts.allow:
4264 ==> exim : <client_list>
4266 ==> /etc/hosts.deny:
4268 ==> exim : <client_list>
4270 Read the \^hosts_access^\ man page for more ways of specifying clients,
4271 including ports, etc., and on logging connections.
4274 Q0706: How can I get POP-auth-before-relay (aka POP-before-SMTP) support in
4277 A0706: A cleaner way of authentication is to use the SMTP AUTH facility, which
4278 does not require a prior use of POP. However, it is possible to do what
4281 Exim 4 supports the ``whoson'' (\?http://whoson.sourceforge.net?\)
4282 facility for doing this. If you set this up, you can do the check in an
4283 Exim ACL by a statement like this:
4285 ==> require condition = \
4286 ${lookup whoson {$sender_host_address}{yes}{no}}
4288 Otherwise you need to arrange for a list of permitted IP addresses to be
4289 maintained in a file or database, and use this in a \hosts\ condition in
4290 an ACL statement. An Exim user has published this recipe:
4292 \#\#\#\#\?http://www.zeiss.cx/memo/computer/linux/email/exim-s-a-p.html?\
4294 Another Exim user submitted the following idea:
4296 Use a script to grab authenticated IP addresses from the log files of
4297 the POP3 and IMAP4 daemons. These are used to create files in the
4298 directory tree \(/var/db/popb4smtp)\. The existence of a file represents a
4299 valid ``popped recently token'' for the IP address used as the filename.
4301 Another script periodically removes stale files from the tree (after two
4302 hours). There's a small race condition here; it's possible for a file
4303 to be deleted just after it has been updated by the script that watches
4304 the logs. For low-volume servers, the odds of hitting this window are
4307 A POPB4SMTP_CLIENT macro in the Exim configure file provides a reusable
4308 ``has this sender popped recently?'' query:
4310 ==> POPB4SMTP_SUBDIR = /var/db/popb4smtp/${substr_-1_1:$sender_host_address}
4311 POPB4SMTP_CLIENT = ${if exists {POPB4SMTP_SUBDIR/$sender_host_address} \
4312 {$sender_host_address} {0} }
4314 Now you can use it just about anywhere, including in your ACLs. Simple
4317 ==> hostlist relay_hosts = 127.0.0.1/32 : ... : POPB4SMTP_CLIENT
4318 host_lookup = !127.0.0.1/32 : ... : !POPB4SMTP_CLIENT
4319 rfc1413_hosts = !127.0.0.1/32 : ... : !POPB4SMTP_CLIENT
4321 The two scripts (and a FreeBSD startup script for them) are available
4324 \#\#\#\#\?http://people.FreeBSD.org/~sheldonh/popb4smtp-nodb.tar.gz?\
4327 Q0707: I have one or two cases where my host correctly rejects messages, but
4328 the remote host is quite persistent, and keeps trying over and over.
4330 A0707: It is an unfortunate fact that a number of SMTP clients, in violation of
4331 the SMTP RFC, do not treat a permanent error code that is given after
4332 the DATA portion of the transaction as a permanent error. Consequently
4333 they keep resending the message, and the worst offenders do so at very
4336 The only way to stop such behaviour is to blacklist the IP address, or
4337 the envelope sender, or both, in such a way that future messages get
4338 rejected at RCPT time instead of at DATA time. You could also complain
4339 to the remote host's administrators.
4342 Q0708: How can I run customized verification checks on incoming addresses?
4344 A0708: There are a number of possibilities:
4346 (1) If you can implement your checks in Perl, you can use Exim's
4347 facility for running an embedded Perl interpreter. For example, if you
4348 want to run special checks on local addresses, you could use ACL
4349 an statement like this:
4351 ==> require domains = my.local.domain
4352 condition = ${perl{verify}{$local_part}}
4354 The result of the Perl function should be ``yes'' or ``no''.
4356 (2) You could also run an external program in a similar way, by a
4359 ==> require domains = my.local.domain
4360 condition = ${run{/my/verifier $local_part}}
4362 This requires the use of another process, so could prove more expensive
4365 (3) If you are prepared to write C code, read the chapter in the manual
4366 entitled \*Adding a local scan function to Exim*\.
4369 Q0709: Does Exim apply RBL checks to error messages, those with an envelope
4372 A0709: This depends on the ACL configuration. You can test for bounce messages
4373 (by looking for an empty sender address) and thereby exclude them from
4374 RBL checking if you want. This ACL statement does that:
4376 ==> deny senders = ! :
4377 dnslist = blackholes.mail-abuse.org
4379 However, some spam does come with an empty sender address, so this may
4383 Q0710: I want to reject certain sender-recipient combinations, with a specific
4384 message for each such combination.
4386 A0710: Set up a file (or database) containing the messages, keyed by the
4387 combination, for example:
4389 ==> sender1@sdomain1=>recipient1@rdomain1: blocked because...
4390 sender2@sdomain2=>recipient2@rdomain2: blocked because...
4392 If you have lots of recipients for the same sender, it might be easier
4393 to generate this file from more convenient data. In your ACL that is run
4394 for each RCPT command, you can then put:
4396 ==> deny message = ${lookup{$sender_address=>$local_part@$domain}\
4397 lsearch{/that/file}}
4398 condition = ${lookup{$sender_address=>$local_part@$domain}\
4399 lsearch{/that/file}{yes}{no}}
4401 The condition is tested first. If the lookup succeeds, the condition
4402 succeeds so access is denied. The message is then expanded, but the
4403 lookup won't be repeated, because Exim will have cached the previous
4406 This approach blocks only incoming SMTP messages. If you need to do
4407 similar blocks for messages that do not arrive over SMTP, you have to
4408 set up a suitable \%redirect%\ router with a \:fail:\ setting.
4411 Q0711: Will Exim allow me to create a file of regexs and match incoming
4412 external email to the list - and if a match is found file the offending
4413 message into a special location? Also is it possible to make Exim only
4414 filter parts of an incoming email - e.g. ignore large MIME attachments
4415 for example and only process text/plain?
4417 A0711: You can do some of this in a system filter. For example:
4419 ==> if $message_body matches <...some complicated regex...> or
4420 $message_body matches <...some other regex...> or
4421 $header_from: matches <...regex...> or
4424 save /some/special/file
4427 or instead of \"save"\ you could have \"deliver"\ (to some address) or
4428 \"pipe"\ (to some script).
4430 There isn't any mechanism for ignoring attachments, but \$message_body$\
4431 only looks at the first n bytes of the body, where n defaults to 500 but
4434 A more expensive alternative would be to run a Perl subroutine using the
4435 embedded Perl mechanism. If you passed over the message id, the Perl
4436 code could read the message files on the spool and implement any
4437 algorithm it liked for deciding what should be done.
4440 Q0712: I've hacked sendmail to make an ioctl call at the time of the SMTP RCPT
4441 command, to check if a user has exceeded their email quota. If they have
4442 I issue a temporary failure and a message - can I do this with Exim?
4444 A0712: If you can make this happen in Perl you can use the embedded Perl
4445 facility, and use it from a \condition\ condition in an ACL statement.
4446 You can also use the expansion facility to run an external program, but
4447 this uses more resources because it uses another process.
4450 Q0713: I'd like to pass all messages through a virus-scanning system before
4451 delivery. Can Exim do this?
4453 A0713: One way of achieving this is to deliver all messages via a pipe to a
4454 checking program that resubmits them for delivery in some private way
4455 that can be checked (e.g. on a specific SMTP port, or IP address). One
4456 possibility is to use the `received protocol` field that can be set
4457 for locally submitted mail via the \-oMr-\ command line option. This
4458 router sends all messages that are not from the local host and whose
4459 received protocol is not \"scanned-ok"\ to the \%virus_scan%\ transport:
4463 transport = virus_scan
4464 condition = ${if or {{eq {$received_protocol}{scanned-ok}} \
4465 {eq {$sender_host_address}{127.0.0.1}}}\
4468 One problem is that this approach, by default, scans the message for
4469 each recipient, not just once per message. However, you can set the
4470 \batch_max\ option on the transport to allow it to send a single copy
4471 for multiple recipients.
4473 The virus_scan transport should be set up to pipe the message to a
4474 suitable checking program or script which runs as a trusted user. This
4475 can then re-submit the message to Exim, using \-oMr-\ to set the received
4476 protocol to \"scanned-ok"\. It is probably easiest to use the Batch SMTP
4477 (BSMTP) facilities for passing the sender address and the recipient
4478 addresses to the checker and then back to Exim (using the \-bS-\
4479 command line option). \**Warning:**\ If you forget to make the
4480 resubmitting process run as a trusted user, the sender address will be
4481 incorrect and what is worse, the received protocol does not get set, and
4482 you are likely to generate a loop.
4485 Q0714: Is there a way to configure Exim to reject mail to a certain local host?
4487 A0714: No, only to certain domains. To reject at SMTP time, you can put a line
4488 like this in your ACL:
4490 ==> deny message = this domain is deliberately rejected
4491 domains = a.certain.domain
4493 To fail addresses in messages that do not arrive over SMTP, you can set
4494 up a router like this:
4496 ==> reject_a_certain_domain:
4498 domains = a.certain.domain
4500 data = :fail: this domain is deliberately rejected
4503 Q0715: How can I get Exim to remove attachments from messages?
4505 A0715: Exim does not contain facilities for modifying messages. You must use
4506 an external program if you want to do this. You can route messages that
4507 have a ::Content-type:: header line via a pipe to a command that does
4508 the job and then re-submits the message to Exim. Alternatively, you
4509 could use a transport filter to do this job.
4512 Q0716: How can I arrange for each user to have a file listing the only sender
4513 addresses from which she will accept mail? I want to do this so my
4514 family members don't get any spam (or other inappropriate mail).
4516 A0716: Let's assume each user has a file called \(.acceptlist)\ in the home
4517 directory. You can put in your ACL a line like this:
4519 ==> require senders = /home/$local_part/.acceptlist
4521 This will reject RCPT commands when the sender is not in the accept
4522 list for the recipient. (Replace \(/home/$local_part)\ with whatever
4523 the correct path to your user's home directories is.)
4525 One problem with this is that it will block bounce messages, which have
4526 empty senders. You can get round this, by changing the line to this:
4528 ==> require senders = : /home/$local_part/.acceptlist
4530 However, this will, of course, let in spam that has a null sender.
4533 Q0717: When using Nessus on a system that runs Exim, a number of security
4534 issues are raised. Nessus complains that Exim answers to EXPN and/or
4535 VRFY; sometimes it even complains that Exim allows relaying.
4537 A0717: Exim supports EXPN and VRFY only if you permit it to do so in the ACLs
4538 defined by \acl_smtp_expn\ and \acl_smtp_vrfy\, respectively. Otherwise,
4541 ==> 550 Administrative prohibition
4542 252 Administrative prohibition
4544 Maybe the use of 252 is the ``problem''. It is recommended that this be
4545 done (by those that discuss these things) because there are stupid
4546 clients that attempt VRFY before sending a message.
4549 Q0718: Could anyone points me to right rules to prevent sending/receiving
4550 messages to/for domains which have one MX to localhost or only have
4556 Q0719: I would like to have a per-user limit for the maximum size of messages
4559 A0719: The simplest way to do this is to put something in a system filter along
4562 ==> if $message_size is above
4563 "${lookup{$sender_address}lsearch{/some/file}{$value}{10M}}"
4565 fail "Message is larger than $sender_address is allowed to send"
4568 In practice, an additional check that the message has arrived from your
4569 local host or local network is probably wise because sender addresses
4573 Q0720: I set \"accept hosts=192.168.122.96/32"\ in order to accept mail for
4574 relaying from my local LAN, but it doesn't work. What's wrong?
4576 A0720: 192.168.122.96/32 is not a network, it is a single host. Exim uses CIDR
4577 notation for specifying networks, where the number after the slash is
4578 the number of bits in the IP address that must match. Your setting says
4579 ``32 bits must match''. If you really mean to specify ``the next 32
4580 IP addresses'', you need 192.168.122.96/27.
4583 Q0721: I have POP-before-SMTP set up on my Exim server, but some clients use
4584 Outlook Express, which sends queued messages before checking the
4585 mailbox, so it doesn't work.
4587 A0721: Implement SMTP authentication.
4590 Q0722: I installed Amavis and it is working, but bounces are simply vanishing.
4592 A0722: Check that you haven't inadvertently set up the transport like this:
4596 command = "/usr/sbin/amavis -f ${sender_address} -d ${pipe_addresses}"
4598 The last line should be:
4600 ==> command = /usr/sbin/amavis -f <$sender_address> -d $pipe_addresses
4602 The important thing is the <> around the sender address; removal of
4603 the unnecessary "" and {} is just tidying. See the amavis FAQ at
4604 \?http://www.amavis.org/amavis-faq.php3?\.
4607 Q0723: I can't get Pine to work with PLAIN authentication; Exim keeps
4608 responding "535 Incorrect authentication data".
4610 A0723: You need to have this setting in your PLAIN authenticator:
4612 ==> server_prompts = :
4614 This is missing in the examples in early Exim documentation, because it
4615 was not realized that PLAIN authentication could be requested by a
4616 client without sending the data with the request. If the data is not
4617 sent, an empty prompt is expected.
4620 Q0724: I have used \":fail:"\ in some aliases; when one of these addresses is
4621 refused, I see the message on the log, but the response to the remote
4622 user is ``unknown user'' instead of the message from the alias file.
4623 How can I change this?
4625 A0724: Have you got a \message\ qualifier in the relevant ACL? Exim uses the
4626 message line in the ACL in preference to the message returned by the
4627 router. This is so you can restrict the amount of information that
4628 ``escapes'' from your site via SMTP if you want to. Remove the \message\
4629 line in the ACL entry that has \"verify = recipient"\ and your message
4632 Alternatively, if you are running Exim 4.10 or later, you can use the
4633 \$acl_verify_message$\ variable in your message to include the message
4634 from the router. See also Q0725.
4637 Q0725: I've set up some specific rejection messages for certain recipients, but
4638 when I test them, the SMTP message is always \*550 5.1.1
4639 <user@mydomain.com>... User unknown*\.
4641 A0725: That is not an Exim message (the ``5.1.1'' is a clue; Exim doesn't use
4642 those extended codes). You are probably being defeated by software that
4643 sees the 550 error code, and insists on putting in its own text. There
4644 is stupid software that does this. You can test Exim by using \-bh-\ or
4645 making a telnet call to the SMTP port. That way, there's no other
4646 software intervening.
4649 Q0726: My SMTP authentication can be bypassed by sending an unknown user name
4650 and an empty password. What is wrong with this condition in a PLAIN
4653 ==> server_condition = ${if eq{$2} {${lookup mysql{SELECT password FROM \
4654 accounts WHERE username='${local_part:$1}'}}}{1}{0}}
4656 A0726: Your lookup item returns an empty string when the user does not exist.
4657 You should instead arrange for the lookup to fail:
4659 ==> server_condition = ${if eq{$2} {${lookup mysql{SELECT password FROM \
4660 accounts WHERE username='${local_part:$1}'}{$value}fail}}{1}{0}}
4663 Q0727: When a message has many recipients, how can I stop SpamAssassin from
4664 being called for each of them? I'm running it from a pipe transport.
4666 A0727: In the transport configuration, set \batch_max\ to a value greater than
4670 Q0728: How do I use Exiscan, SA-Exim, SpamAssassin, Clam Antivirus, Sophos
4671 SAVI, or sophie with Exim?
4673 A0728: There's a mini-HOWTO about these available via
4674 \?http://www.timj.co.uk/linux/exim.php?\.
4675 See also sample configuration C047.
4678 Q0729: How can I screen out addresses that are neither valid usernames or
4679 distribution lists on mail being forwarded to an internal Win2K server?
4681 A0729: A user suggested using a router like this to do the recipient
4684 ==> verify_user_router:
4686 domains = win2kdomain.com
4688 ldap;user="cn=ldap-guest,cn=Users,dc=win2kdomain,dc=com"\
4690 ldap:://win2kpdc/dc=win2kdomain,dc=com?mailNickname?\
4691 sub?(&(mailNickname=$local_part)\
4692 (showInAddressBook=*)(sAMAccountName=*))
4695 Set up ldap-guest as a normal domain user on the Win2K PDC.
4697 Also, you need to set \no_verify\ on all the other routers that handle
4701 Q0730: How can I use the same passwords for SMTP authentication as I use for
4702 Courier IMAP access to my server?
4704 A0730: You can access the Courier authdaemon from an Exim authenticator. You
4705 must arrange for the Exim user (often \/exim/\ but sometimes \/mail/\)
4706 to be able to access \(/var/run/courier/authdaemon/socket)\. The
4707 configuration is something of a hack, but it is reported to work. Here
4708 is a LOGIN authenticator:
4713 server_prompts = Username:: : Password::
4714 server_condition = \
4715 ${if eq {${readsocket{/var/run/courier/authdaemon/socket}\
4716 {AUTH 76\n${length_76:exim\nlogin\n$1\n$2\
4717 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
4718 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
4719 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n}}}}{FAIL\n} {no}{yes}}
4722 Here is a PLAIN authenticator:
4728 server_condition = \
4729 ${if eq {${readsocket{/var/run/courier/authdaemon/socket}\
4730 {AUTH 76\n${length_76:exim\nlogin\n$2\n$3\
4731 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
4732 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
4733 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n}}}}{FAIL\n} {no}{yes}}
4737 Q0731: Is there any defence I can use against spam sent through an open proxy?
4739 A0731: The \*ident*\ feature can be used in some cases. See the discussion in
4743 Q0732: I would like to either warn or deny when a host uses an underscore in
4748 ==> helo_allow_chars = _
4750 This tells Exim not to reject the EHLO or HELO command immediately. Once
4751 you have done that, you can test for the underscore in an ACL. For
4752 example, to log a warning for hosts in your LAN, and reject for other
4753 hosts, you could do something like this:
4755 ==> deny message = Underscores are not valid in host names
4756 hosts = ! +lan_hosts
4757 condition = ${if match{$sender_helo_name}{_}{yes}{no}}
4759 ==> warn log_message = Accepted underscore from [$sender_host_address]
4760 condition = ${if match{$sender_helo_name}{_}{yes}{no}}
4763 Q0733: Is there any way to tell Exim not to lookup the IP address against any
4764 DNS black list if the connection is over IPv6?
4766 A0733: Use this condition in your ACL:
4768 ==> condition = ${if match{${mask:$sender_host_address/0}}\
4769 {${mask:::0/0}}{no}{yes}}
4771 From Exim 4.23 onwards, this can be simplified to
4773 ==> condition = ${if isip6{$sender_host_address}{no}{yes}}
4776 Q0734: How do MailScanner and Exiscan compare? What are the pros and cons?
4778 A0734: The big advantage of Exiscan is that it can reject messages at SMTP time
4779 before you have accepted responsibility for them, which means you don't
4780 have to deal with bouncing messages and thereby becoming a collateral
4783 The big advantage of MailScanner is that it gives you much greater
4784 control over the load on your machines. You configure it according to
4785 the maximum processing capacity of your computer and it will not exceed
4786 that; in fact because it deals with messages in batches the cost of
4787 processing a message actually goes down slightly as the load increases,
4788 because the per-batch costs are shared by more messages.
4790 With Exiscan, you have to rely on Exim's load protection mechanisms,
4791 which basically means that you have to stop accepting messages when your
4792 machine gets too loaded. This is bad if the machine happens to be an
4793 SMTP smarthost. You therefore need more overcapacity with Exiscan than
4797 Q0735: How can I block non-FQDNs in HELO/EHLOs?
4799 A0735: Many workstation clients send single-component names; take care that you
4800 do not block legitimate mail. With that proviso, you can do it using
4801 something like this in an ACL:
4803 ==> drop message = HELO doesn't look like a hostname
4804 log_message = Not a hostname
4805 condition = ${if match{$sender_helo_name} \
4806 {\N^[^.].*\.[^.]+$\N}{no}{yes}}
4808 This means: Drop the HELO unless it contains a dot somewhere in the HELO
4809 string, but the string may not begin or end with a dot. Thus, the
4810 imposed minimum length is 3 characters.
4812 The data for HELO/EHLO doesn't have to be a host name; it may
4813 legitimately be an IP address literal instead. The above test succeeds
4814 with an IPv4 address literal, but if you want also to accept IPv6
4815 address literals, you will have to modify the regular expression.
4818 Q0736: Is it possible to tell exim to drop the connection after a server
4819 attempts to send a message to a number of unknown users?
4821 A0736: Yes. Use \$rcpt_fail_count$\ and the \^drop^\ ACL command, as in this
4824 ==> drop message = Too many unknown users
4825 condition = ${if >{$rcpt_fail_count}{15}{yes}{no}}
4828 Q0737: Is there some way to tell Exim not to consider 127.0.0.1 as a valid MX?
4833 Q0738: How can I configure Exim to delay the SMTP connection if more than 10
4834 invalid recipients are received in one message?
4836 A0738: Put something like this in your RCPT ACL:
4838 ==> deny message = Max $rcpt_fail_count failed recipients allowed
4839 condition = ${if >{$rcpt_fail_count}{10} {1}}
4840 ! verify = recipient
4841 delay = ${eval: $rcpt_fail_count * 10}s
4842 log_message = $rcpt_fail_count failed recipient attempts
4844 This example increases the delay for each failed recipient.
4847 Q0739: Does Exim support SPF?
4849 A0739: An Exim ACL can be used. See \?http://spf.pobox.com/downloads.html?\.
4852 Q0740: How can I change the MAIL FROM address that is used for callouts?
4854 A0740: It depends on which type of callout you are using.
4856 (1) For envelope sender verification callouts, you cannot make any
4857 change. My view is that an envelope sender verification is testing
4858 whether Exim could send a bounce to that address. Therefore, it must
4859 use \"MAIL FROM:<>"\ because that is what it would do if it were
4860 sending a bounce message. If \"MAIL FROM:<>"\ is rejected, it means
4861 Exim could not send a bounce. Therefore the callout fails.
4863 (2) For verifying addresses in the ::From::, ::Sender::, or ::Reply-to::
4864 header lines (the \"verify = header_sender"\ condition), it is
4865 possible to make a change, on the grounds that these addresses are
4866 not necessarily ones that must accept bounce messages. You can do
4867 this by adding a \"mailfrom"\ option, like this:
4869 ==> require verify = header_sender/callout=mailfrom=abcd@x.y.z
4871 (3) It is also possible to make a change for the postmaster verification
4872 option, also on the grounds that a postmaster address need not
4873 accept bounces if it is never used as an envelope sender. Instead of
4874 just \"postmaster"\, \"postmaster_mailfrom"\ is used, like this:
4876 ==> require verify = sender/callout=postmaster_mailfrom=abcd@x.y.z
4878 (4) For recipient verification, there are three possibilities. The
4879 default is to use \"MAIL FROM:<>"\. If the \use_postmaster\ option
4880 is given, for example:
4882 ==> require verify = recipient/callout=use_postmaster
4884 then the address for MAIL FROM is made up from the local part
4885 \"postmaster"\ and the contents of \$qualify_domain$\.
4887 Alternatively, if the \use_sender\ option is given, the sender
4888 address of the incoming message is used. You should use this option
4889 only when you know that the receiving host makes use of the sender
4890 address when verifying. The reason is that the callout cache is much
4891 less effective in this case, causing many more callouts to be
4894 In all cases when you configure Exim to use a non-empty address in MAIL
4895 FROM during callout processing, you should think carefully about what
4896 might happen if this causes the called host to make its own callout back
4897 to your host. Make sure that callout loops cannot happen.
4900 Q0741: How can I get Outlook Express to use TLS when authenticating?
4902 A0741: If you check \"auth required"\ in OE, it will authenticate as soon as
4903 it sees AUTH LOGIN, in preference to STARTTLS. The trick is to
4904 advertise things to OE in a certain order. The first EHLO should
4905 advertise STARTTLS but not AUTH, and only the second EHLO (after TLS
4906 starts) should advert AUTH. One way of achieving this is to put, in
4907 the main section of your Exim configuration:
4909 ==> auth_advertise_hosts = ${if eq{$tls_cipher}{}{127.0.0.1}{*}}
4911 This means that the only host to which AUTH is advertised is 127.0.0.1
4912 when the session is not encrypted (that is, before TLS has started). The
4913 idea here is that there's no need for encryption for anything coming via
4914 the loopback interface. For an encrypted session, however, AUTH is
4915 advertised to all hosts.
4917 You can also block the AUTH command itself for unencrypted connections,
4918 by creating an ACL for \acl_smtp_auth\ that is something like this:
4920 ==> accept encrypted = *
4921 accept hosts = 127.0.0.1
4922 deny message = TLS encryption required before AUTH
4926 8. REWRITING ADDRESSES
4928 Q0801: How can I get Exim to strip the hostname from the sender's address?
4930 A0801: If you set up a rewriting rule in the following form:
4932 ==> *@*.your.domain $1@your.domain
4934 then Exim will rewrite all addresses in the envelope and the headers,
4935 removing anything between \"@"\ and \"your.domain"\. This applies to all
4936 messages that Exim processes. If you want to rewrite sender addresses
4937 only, the the rule should be
4939 ==> *@*.your.domain $1@your.domain Ffrs
4941 This applies the rule only to the envelope sender address and to the
4942 ::From::, ::Reply-to::, and ::Sender:: headers.
4945 Q0802: I have Exim configured to remove the hostname portion of the domain on
4946 outgoing mail, and yet the hostname is present when the mail gets
4949 A0802: Check the DNS record for your domain. If the MX record points to a CNAME
4950 record instead of to an A record, some MTAs (not Exim) are liable to
4951 rewrite addresses, changing your domain name to its ``canonical'' form,
4952 as obtained from the CNAME record.
4955 Q0803: I want to rewrite local addresses in mail that goes to the outside
4956 world, but not for messages that remain within the local intranet.
4958 A0803: You can use the \headers_rewrite\ option on a transport to do this.
4959 The rewriting will then apply to just those copies of a message that
4960 pass through the transport. The \return_path\ option can similarly be
4961 used to rewrite the sender address. There is no way of rewriting
4962 recipient addresses at transport time. However, as these are by
4963 definition remote addresses, you probably don't want to rewrite them.
4965 You have to set up the configuration so that it uses different SMTP
4966 transports for internal and external mail. If you are using a single
4967 router in both cases, you could configure it like this:
4971 transport = ${if match{$domain}{\N\.my\.domain$\N}{int_smtp}{ext_smtp}}
4973 This example uses the \%int_smtp%\ transport for domains ending in
4974 \(.my.domain)\, and \%ext_smtp%\ for everything else. The \%ext_smtp%\ transport
4975 could be something like this:
4979 headers_rewrite = *@*.my.domain \
4980 ${lookup{$1}cdb{/etc/$2/mail.handles.cdb}{$value}fail}
4982 ${if match{$return_path}{\N^([^@]+)@(.*)\.my\.domain$\N}\
4984 ${lookup{$1}cdb{/etc/$2/mail.handles.cdb}{$value}fail}\
4988 This example uses a separate file of local-to-external address
4989 translations for each domain. This is not the only possibility, of
4990 course. The \headers_rewrite\ and \return_path\ options apply the same
4991 rewriting to the header lines and the envelope sender address,
4995 Q0804: I'm using this rewriting rule to change login names into ``friendly''
4996 names, but if mail comes in for an upper case login name, it doesn't
4999 ==> *@my.domain ${lookup{$1}dbm{/usr/lib/exim/longforms}\
5000 {$value}fail}@my.domain bcfrtFT
5002 The longforms database has entries of the form:
5004 ==> ano23: A.N.Other
5006 A0804: Replace \"$1"\ in your rule by \"${lc:$1}"\ to force the local part to lower
5007 case before it is used as a lookup key.
5010 Q0805: Is it possible to completely fail a message if the rewrite rules fail?
5012 A0805: It depends on what you mean by ``fail a message'' and what addresses you
5013 are rewriting. If you are rewriting recipient addresses for your local
5016 ==> *@dom.ain ${lookup{$1}dbm{/wher/ever}{$value}{failaddr}} Ehq
5018 and in your alias file put something like
5020 ==> failaddr: :fail: Rewriting failed
5022 This fails a single recipient - others are processed independently.
5025 Q0806: I'm using \$domain$\ as the key for a lookup in a rewriting rule, but its
5026 contents are not being lowercased. Aren't domains supposed to be handled
5029 A0806: The value of \$domain$\ is the actual domain that appears in the address.
5030 It could of course be lower cased, but I know that would cause some
5031 unhappiness, because some people have mixed-case domain names which look
5032 silly if the case is changed. Thus, one wants to preserve the case in
5035 ==> *@*.TheRap.com something@$domain
5037 because ``therap'' doesn't look like two words. I know it seems trivial,
5038 but it is important to some people - especially if by some unfortunate
5039 accident the lowercased word is something indecent.
5041 You can trivally force lower casing by means of the \"${lc:"\ operator.
5042 Instead of \"$domain"\ write \"${lc:$domain}"\.
5045 Q0807: I want to rewrite local sender addresses depending on the domain of the
5048 A0807: In general, this is not possible, because a message may have more than
5049 one recipient and Exim keeps just a single copy of each message. It may
5050 also deliver one copy of a message with several recipient addresses.
5051 You can do an incomplete job by using a regular expression match in a
5052 rewrite rule to test, for example, the contents of the ::To:: header. This
5053 would work except in cases of multiple recipients.
5059 Q0901: I would like add some custom headers to selected outgoing mail based on
5060 a specific domain and the subject line.
5062 A0901: To the remote_smtp transport, add something like
5064 ==> headers_add = ${if and{\
5065 {eq{$domain}{spec.dom}}\
5066 {matches{$h_subject:}{whatever}}}\
5067 {Content-Type: text/html; charset="us-ascii"} fail }
5069 This example shows a ::Content-Type:: header, but you can have anything you
5070 like, and multiple headers can be inserted by using \"@\n"\ to separate them.
5073 Q0902: Is it possible to have Exim add a header to only certain local parts of
5076 A0902: Only if you arrange for each such local part to receive its own private
5077 copy of the mail. See \max_rcpt\ in the SMTP transport. If you set this
5078 to 1, you could use conditions in an expansion string to add or not add
5082 Q0903: How can I remove some part of the ::Received:: header?
5084 A0903: Set \received_header_text\.
5087 Q0904: How I can insert the PGP header line using Exim filters?
5089 A0904: You can't insert headers in a user filter. A system filter can do so,
5090 but the inserted lines then are included for all recipients.
5093 Q0905: I know I can use a system filter to replace certain headers in messages,
5094 but how can I add text to existing headers? I want to add [SPAM] to
5095 the subject line of messages that appear to be spam.
5097 A0905: You can only do this in a round about way, using filter commands like
5100 ==> headers add "New-Subject: SPAM: $h_subject:"
5101 headers remove subject
5102 neaders add "Subject: $h_new-subject:"
5103 headers remove new-subject
5105 This trick works only in system filters, where the commands are obeyed
5106 in order, and affect the master list of headers that apply to the whole
5107 message. You cannot do this with the \headers_add\ and \headers_remove\
5114 Q1001: I'm running a large mail server. Should I set \split_spool_directory\ to
5115 improve performance?
5117 A1001: Splitting the spool directory has most benefit if there are times when
5118 there are a large number of messages on the queue. If all mail is
5119 delivered very quickly, and the queue is always less than, say, a few
5120 hundred messages, there isn't any need to do this. With larger queues,
5121 there is a definite performance benefit to splitting the spool. It shows
5122 up earlier on some types of file system, compared with others.
5124 Exim was not designed for handling large queues. If you are in an
5125 enviroment where lots of messages remain on the queue for long periods
5126 of time, consider implementing a back up host to which you pass these
5127 messages, so that the main host's queue remains short. You can use
5128 \fallback_hosts\ to do this, or a router that is conditional on
5132 Q1002: How well does Exim scale?
5134 A1002: Although the author did not specifically set out to write a high-
5135 performance MTA, Exim does seem to be fairly efficient. The biggest
5136 server at the University of Cambridge (a large Sun box) goes over
5137 100,000 deliveries per day on busy days (it has over 20,000 users).
5138 There was a report of a mailing list exploder that sometimes handles
5139 over 100,000 deliveries a day on a big Linux box, the record being
5140 177,000 deliveries (791MB in total). Up to 13,000 deliveries an hour
5143 These are quotes from some Exim users:
5145 "... Canada's largest internet provider, uses Exim on all of our mail
5146 machines, and we're absolutely delighted with it. It brought life back
5147 into one of our machines plagued with backlogs and high load averages.
5148 Here's just an example of how much email our largest mail server
5149 (quad SS1000) is seeing ... " [230,911 deliveries in a day: 4,475MB]
5151 "... Exim has to ... do gethostbyname()s and RBL lookups on all of the
5152 incoming mail servers, and he runs from inetd (TCP Wrappers connected).
5153 All the same, it seems to me that he runs as fast as lightning on our
5154 SCO 5.0.4 box (1 Pentium 166) - far faster than MMDF which I (and many
5155 customers) had before."
5157 "On a PII 400 with 128M of RAM running Linux 2.2.5, I have achieved
5158 36656 messages per hour (outgoing unique messages and recipients). For
5159 about a 5 minute period, I was able to achieve an average of 30 messages
5160 per second (that would be 108000 m/hour)! We are using: (options that
5164 split_spool_directory
5166 remote_max_parallel = 1
5168 We have a cron job hat runs every five minutes that spawns 5 \"exim -q"\ if
5169 there are less that 120 exim processes currently running. We found
5170 that by manually controlling the concurrency of \"exim -q"\ processes
5171 contending for the spool for \%remote_smtp%\ delivery that we gained
5172 considerable performance - 10000 m/hour."
5175 Q1003: We have a large password file. Can Exim use alternative lookups during
5176 delivery to speed things up?
5178 A1003: If you are using FreeBSD, this problem should not arise, because it
5179 automatically uses an indexed password file. In some other operating
5180 systems you can arrange for this to happen too. On Linux, for example,
5181 all you need to do is
5186 and put \"db"\ before \"files"\ in any \(/etc/nsswitch.conf)\ lines you want to
5189 On systems that do not include support for indexed password files, you
5190 can build one yourself, and reference it from the Exim configuration.
5191 For example, for routing to local mailboxes you could use this:
5195 condition = ${lookup{$local_part}cdb{/etc/passwd.cdb}{yes}{no}}
5196 transport = local_delivery
5197 user = ${extract{1}{:}{${lookup{$local_part}cdb{/etc/passwd.cdb}}}
5199 This assumes a cdb version of the password file.
5202 Q1004: I just wondered if it might be helpful to put the hints database on a
5203 RAM disk during regular operation. Did anybody try that yet?
5205 A1004: A user reported thus: ``I have found that this works great under Solaris.
5206 Make a RAM disk partition and keep everything in the \(db)\ directory on
5207 it. However, when I try the same thing on Linux, I don't see the same
5208 boost. I think that Linux's file buffer cache works about the same.
5209 Plus, this leave more room for processes to run.''
5211 There have been other reports that Linux's delayed buffer write provides
5212 better overall performance in general.
5214 Apparently there is support in the Solaris kernel for a delayed writing,
5215 as in Linux, but Sun's server policy is to have it disabled so that you
5216 don't lose so much if the server crashes. There is a program called
5217 \^fastfs^\ to enable and disable this support. You have to download and
5218 compile it yourself; find it by looking for \"fastfs.c"\ in a search
5219 engine. Solaris performance is reported to be much improved, but you
5220 should take care to understand the potential hazards. In particular,
5221 \^fsck^\ may be unable to ``fix'' disks automatically after a crash.
5224 Q1005: A lot of incoming mail is pushing up my system load too much, and there
5225 are many Exim processes. How can I control this?
5227 A1005: Have you set any of the Exim configuration options that limit what it
5228 does under high load? For example, queue_only_load, deliver_queue_load_max?
5229 See the list in the section entitled \*Resource control*\ in the manual.
5231 It sounds like a lot of simultaneous incoming mail pushes your system
5232 into uncontrolled overload. The multiple Exim processes are probably
5233 just multiple incoming messages. You can use the \^exiwhat^\ utility to
5240 Q1101: How do I set up Majordomo to work with Exim?
5242 A1101: Users have found several ways of setting up Exim for use with Majordomo.
5243 One way has been documented at
5244 \?http://www.averillpark.net/exim/majordomo.html?\.
5246 Somewhere in the Majordomo docs or FAQ it mentions using batchmail or
5247 other additional programs to improve the performance of large lists.
5248 They are not needed with Exim, and their use can actually make things
5249 worse. However, it's a good idea to set \remote_max_parallel\ to a value
5250 greater than 1 in the Exim configuration.
5253 Q1102: I have set \$mailer$\ in \(majordomo.cf)\, but it still isn't setting the
5254 sender correctly in the messages it sends.
5256 A1102: Make sure you have got the quoting correct in the \$mailer$\ setting. For
5259 ==> $mailer = "$sendmail_command -oi -oee -f$sender\@lists.mydomain.de";
5261 is not correct. It needs three backslashes, not one, and the $ at the
5262 start of \$sender$\ has to be escaped with a backslash.
5265 Q1103: I'm trying to set up majordomo, but I'm getting a wrong mode error
5266 when I try to send it mail.
5268 A1103: Check the mode of \(/var/lib/majordomo/lists/lists.aliases)\ and compare it
5269 with the setting of the \modemask\ option in the Majordomo aliases
5270 router. This option specifies bits which must not be set for the alias
5271 file, and it defaults to 022.
5274 Q1104: I'm getting return code 9 from \(/home/majordomo/majordomo-1.94.4/wrapper)\
5275 when it is passed a message from Exim.
5277 A1104: A problem like this turned out to be the Perl version that came with
5278 RedHat 5.2. Rebuilding Perl 5.005x solved it.
5281 Q1105: Exim is complaining about an invalid command line when Majordomo tries
5282 to send it a message for delivery.
5284 A1105: Take a look at your \(majordomo.cf)\ file, It should have something that
5287 ==> $sendmail_command = "/usr/lib/sendmail";
5289 and another line like
5291 ==> $mailer = "$sendmail_command -oi -oee -f\$sender";
5293 If you have modified \^resend^\ (one of the majordomo programs) to use
5294 \$sendmail_command$\ instead of \$mailer$\ you will be calling Exim with no
5295 command line arguments.
5301 Q1201: When I run fetchmail, I get the error \*SMTP listener doesn't like
5302 recipient address xxx@localhost*\.
5304 A1201: Make sure that //localhost// is recognized as a domain that is to be
5305 delivered locally. If you are using the default Exim run time
5306 configuration, you'll see a line near the top like this:
5308 ==> domainlist local_domains = @
5312 ==> domainlist local_domains = @ : localhost
5315 Q1202: I'm currently using Exim with fetchmail and I'd like to use the RBL on
5316 Exim, but will it work? Do I need to configure fetchmail any particular
5317 way? As far as Exim knows, all mail is coming from 127.0.0.1. Will it
5318 check the source address against RBL? Or will it check the ::From:: header?
5320 A1202: It will check 127.0.0.1 (not very useful). The point of the RBL is to
5321 keep messages from black-listed hosts out of your machine. If you are
5322 using fetchmail, you have got the messages into your machine before you
5323 approach Exim. That kind of defeats the purpose of the RBL. The right
5324 way to do this would be for the host from which you fetch your mail to
5325 do the RBL checking and insert some kind of warning header for you to
5326 test, as Exim does if you run RBL checks in warning mode.
5332 Q1301: Exim built with Perl support exits with the error message \*./exim: can't
5333 load library 'libperl.so'*\.
5335 A1301: If you are using BSDI, see Q9401.
5338 Q1302: Exim built with Perl support exits with several error messages of the
5339 form \*undefined reference to `PL_stack_sp'*\.
5341 A1302: This has been seen on FreeBSD systems that had two different versions of
5342 Perl installed, the older with an \^a.out^\ library and the newer with an
5343 ELF library. Ensure that the older package is removed.
5347 14. DIAL-UP AND ISDN
5349 Q1401: When I'm not connected to the Internet, how can I arrange for mail to
5350 other hosts on my local network to be delivered, while at the
5351 same time mail to Internet hosts is queued without any delivery
5354 A1401: Use the \queue_domains\ option to control which domains are held
5355 on the queue for later delivery. For example,
5357 ==> queue_domains = ! *.localnet
5359 allows delivery to domains ending in \(.localnet)\, while queueing all the
5363 Q1402: I have a dial-up machine, and I use the \queue_smtp_domains\ option so
5364 that remote mail only goes out when I do a queue run. However, any email
5365 I send with an address \(anything@aol.com)\ is returned within about 15
5366 minutes saying \*retry time exceeded*\, and all addresses are affected.
5368 A1402: You should be using \queue_domains\ rather than \queue_smtp_domains\.
5369 With the latter, Exim is trying to route the addresses, which involves a
5370 DNS lookup. This is presumably timing out, causing a retry time to be
5371 set for the domain, and somehow a valid lookup never happened before the
5372 maximum retry time (default of 4 days) passed. Hence the bounce. The
5373 fact that it is \(aol.com)\ is probably not relevant. You should probably
5374 also be using \-qq-\ to do your queue run rather than \-q-\.
5377 Q1403: How should Exim be configured when it is acting as a temporary storage
5378 system for a domain on a dial-up host?
5380 A1403: Exim isn't really designed for this, but... The lowest-numbered MX
5381 record for the domain should be pointing to the dial-up host. A higher
5382 numbered MX record (lower priority) should point to the Exim server that
5383 is acting as a temporary storage system.
5385 You should set a large retry time for the domain, so that Exim doesn't
5386 keep trying to deliver when the host is offline. When the host comes
5387 online, the waiting messages have to be kicked somehow. This can be done
5388 by calling Exim with the \-R-\ option, or via the SMTP ETRN command.
5390 This works provided the number of messages is low. If you are handling
5391 lots of mail, keeping messages waiting for their host to connect and
5392 those that are having delivery problems to remote hosts all in the same
5393 queue doesn't work so well. It is better in this case to get Exim to
5394 deliver the mail for the dial-in hosts into some local files which then
5395 get transmitted by other software when the host connects. One tool for
5396 doing this can be found at \?http://cr.yp.to/serialmail.html?\.
5398 For further discussion, see section entitled \*Intermittently connected
5399 hosts*\ in the manual, and also the section in the Exim book with the
5403 Q1404: I have \queue_domains\ or \queue_smtp_domains\ set, and use \-qf-\ to
5404 force delivery of waiting mail when I dial in. How can I arrange for any
5405 new messages that arrive while I'm connected to be delivered immediately?
5407 A1404: Instead of \queue_domains\ or \queue_smtp_domains\, use the \queue_only_file\
5408 option. This causes messages to be queued if a particular file exists.
5409 If you put the word ``smtp'' before the file name, the queueing applies
5410 only to domains that are delivered by SMTP, thus not affecting local
5413 ==> queue_only_file = smtp/etc/present/when/not/connected
5415 Then, in the scripts which are run when you connect and disconnect,
5416 arrange to remove the file after connection, and create it just before
5420 Q1405: I have an ISDN connection and would like a way of running the queue
5421 automatically when it is up.
5423 A1405: The following shell commands test for the interface being up and then
5426 ==> ifconfig ppp0 | fgrep UP >/dev/null
5427 if [ $? -eq 0 ] ; then exim -q ; fi
5429 You could put these commands into a script which runs them at regular
5430 intervals. You might want to use \-qq-\ instead of \-q-\.
5432 With Linux, the script \(/etc/ppp/ip-up)\ is run after a ISDN connection
5433 or a more general PPP connection has been established. If you are using
5434 Linux, you could put the call to Exim in that script.
5437 Q1406: When I dial up to collect mail from my ISP, only the first 10 messages
5438 get delivered immediately; the remainder just sit on the queue until a
5439 queue runner process finds them.
5444 Q1407: RFC 1985 specifies that the SMTP command \"ETRN host.domain"\ causes all
5445 mail queued for that host, no matter what domain it's for, to be
5446 delivered. Why doesn't Exim support this?
5448 A1407: Exim does not keep queues of mail for specific destinations. It just
5449 keeps one pool of undelivered messages. What is more, once you start a
5450 delivery of a message, it tries to deliver to all the addresses in the
5451 message, not just the one you may be interested in. (Of course, this
5452 doesn't usually do any harm.)
5454 The only way it could be done within Exim would be, for every message
5455 on the queue, to go through the motions of routing each undelivered
5456 address and see if that resulted in a delivery to the host of interest.
5457 This could be extremely expensive (e.g. 1,000 messages on the queue,
5458 only 1 for the given host).
5460 The bottom line is that Exim just wasn't designed for this kind of
5461 operation, that is, holding messages for intermittently connected hosts.
5462 The queueing arrangements are designed for handling delivery problems
5463 that are not expected to be common.
5465 A better way to do this is to implement the required queues separately.
5466 After all, keeping such mail on an active queue (where Exim will keep
5467 trying to deliver) is silly. If there is a lot of mail for these hosts,
5468 it also masks genuine delivery problems when you inspect the queue.
5470 Large ISPs who provide this kind of functionality do not usually leave
5471 waiting mail on the MTA's queue. Instead, they get it delivered into
5472 per-host directories, one message per file, in one of the special
5473 formats (BSMTP, maildir, or mailstore) and when an ETRN arrives, it
5474 kicks off some completely different program that establishes an SMTP
5475 connection to the host and shovels the waiting mail down it. That seems
5476 to me to be a much neater way of doing this. It means you can easily add
5477 additional functionality such as archiving or throwing away uncollected
5480 One program that has this functionality is \^ssmtp^\, which can be
5481 found in \?ftp://metalab.unc.edu/pub/Linux/system/mail/mta/?\.
5482 Alternatively, sample configuration C037 demonstrates an elegant way of
5483 using Exim itself to deliver the saved messages when the client issues
5487 Q1408: If email has been deferred to a member on a local mailing list
5488 (implemented through forward files), and one of our ETRN clients is on
5489 this mailing list, the \-R-\ won't flush the mailing list message for
5492 A1408: That is because \-R-\ matches only original recipient addresses, not those
5493 produced as a result of expansion, because these are not (by default)
5494 preserved from delivery to delivery. You can get round this by setting
5495 \one_time\ on the forwarding router, but you are not allowed to have
5496 expansions to pipes or files on routers that have \one_time\ set.
5497 Therefore, you will have to have a separate router for mailing lists
5498 (with \one_time\ set) to the one used for normal forward files that might
5499 specify pipe or file deliveries. However, the problem will still be
5500 present for any user who sets up a \(.forward)\ file to redirect to any of
5501 the ETRN domains. See the last 3 paragraphs of Q1407 for a discussion of
5502 an alternative approach.
5505 Q1409: I would like to have a separate queue per domain for hosts which dial
5506 in to collect their mail.
5508 A1409: Exim isn't really designed for this kind of operation. The only way to
5509 do this would be to cause it to send those messages to a differently
5510 configured version of Exim with its own spool area. This could be done
5511 via a pipe or SMTP to a private port. The main Exim, listening on port
5512 25, would then be configured to run an appropriate command to prod one
5513 of the others when it received ETRN, by means of the \smtp_etrn_command\
5516 You could probably manage this with a single Exim binary and a number of
5517 different configuration files, passed to the special versions using the
5518 \-C-\ option. For this application they could all run as \^exim^\, since no
5519 root privilege would be needed.
5521 An alternative approach id to get Exim to deliver mail for such hosts
5522 in batch SMTP format into some directory, and have the ETRN run
5523 something to pass such messages to the dialled-in host. See also Q1403.
5529 Q1501: The MX records for some UUCP domains point to my local host. How do I
5530 get it to pass the messages on to UUCP?
5532 A1501: The simplest way is to create a file containing a list of domains, and
5533 the hosts to which their messages should be sent, like this:
5535 ==> uucp1.domain.example: uucp1.host.example
5536 uucp2.domain.example: uucp2.host.example
5539 Then you can use a router like this:
5543 domains = lsearch;/etc/uucp/domains
5544 transport = uucp_transport
5546 and a transport like this:
5551 command = /usr/local/bin/uux - -r $domain_data!rmail $local_part
5554 The \$domain_data$\ variable retains the value that is looked up when
5555 the \domains\ option in the router is matched.
5558 Q1502: How can I get Exim to handle ``bang path'' addresses?
5560 A1502: In general, you can't (Exim is an Internet mailer and recognizes only
5561 RFC 2822 domain-style addresses) but some restricted kinds of bang path
5562 can be dealt with by appropriate rewriting - but please note the warning
5565 Exim treats a bang path address as an unqualified local part, and so
5566 will qualify it with your domain. A rule such as
5568 ==> \N^([^!]+)!(.+)@your\.domain$\N $2@$1
5570 turns \(a!b@your.domain)\ into \(b@a)\. You can also use a repeating rule to
5571 turn multi-component paths into the ``percent hack'' notation with a rule
5574 ==> \N^([^!]+)!([^@%]+)(.+)$\N $2%$1$3 R
5576 which turns \(a!b@c)\ into \(b%a@c)\ and \(a!b!c@d)\ first into \(b!c%a@d)\ and then,
5577 because of the R flag, into \(c%b%a@d)\. The R flag causes repetition up to
5580 \**Warning:**\ If you install a general rewriting rule like the above, you are
5581 opening yourself up to the possibility of unwanted relaying. A host that
5582 is not permitted to relay through your system could send a message with
5583 an SMTP command line such as
5585 ==> RCPT TO:<victim-host!victim-user@your.domain>
5587 and this would be accepted because it is addressed to your domain.
5588 However, the rewriting then converts the address, and the message does
5589 in fact get relayed. One way round this, if all your bang path messages
5590 are passed to Exim via SMTP, is to use the \"S"\ rewriting flag. This
5591 applies a rewriting rule to incoming SMTP addresses as soon as they are
5592 received, before checking for qualification, relaying, etc. So a rule
5595 ==> \N^([^!]+)!(.+)$\N $2@$1 S
5597 rewrites simple two-component bang paths before the result is checked
5598 for relaying. However, this does not rewrite addresses in the headers of
5602 Q1503: We see something strange on our system in regards to mail coming in via
5603 rmail from a UUCP link. The sender is being set to mailmaster instead of
5604 the real sender, and a ::Sender:: header is being added to the message.
5606 A1503: If \(mailmaster)\ is the user that is running rmail, you need to include
5607 that user in the \trusted_users\ configuration option. Only trusted users
5608 are permitted to specify senders when mail is passed to Exim via the
5613 16. MODIFYING MESSAGE BODIES
5615 Q1601: How can I add a disclaimer or an advertisement to a message?
5617 A1601: There are a number of technical and potential legal problems that arise
5618 in connection with message modification. Some of them are listed below.
5619 Some comment on the legal position of email disclaimers in English law
5620 can be found at \?http://www.weblaw.co.uk/artemail.htm?\.
5622 See also \?http://www.goldmark.org/jeff/stupid-disclaimers/?\. There is
5623 some discussion about the problems of actually adding disclaimers in
5624 \?http://www.goldmark.org/jeff/stupid-disclaimers/apply.html?\.
5626 In many cases, email disclaimers will make your company look ridiculous,
5627 at the very least. At worst, they may interfere with the normal
5630 If, despite these considerations, you still want to modify messages, you
5631 can do so using Exim, but not directly in Exim itself. It is not the job
5632 of an MTA to modify messages, something that requires understanding of
5633 their content and format.
5635 Exim provides a hook called a ``transport filter'' that lets you pass
5636 any outgoing message through a program or script of your choice. It
5637 is the job of this script to make any changes to the message that you
5638 require. By this means, you have full control over what changes are
5639 made, and Exim does not need to know anything about message bodies.
5640 However, using a transport filter requires additional resources, and may
5641 slow down mail delivery.
5643 You can use Exim's routers to arrange for those messages that you want
5644 to modify to be delivered via a transport filter. For example, suppose
5645 you want to do this for messages from addresses in your domain that are
5646 being delivered to a remote host. First you need to set up a special
5647 \%smtp%\ transport that uses a filter, like this:
5649 ==> remote_smtp_filter:
5651 transport_filter = /your/filter/command
5653 Then you need to modify the \%dnslookup%\ router to use this transport
5654 when the conditions are right:
5658 domains = ! +local_domains
5659 transport = ${if eq {$sender_address_domain}{your.domain}\
5660 {remote_smtp_filter}{remote_smtp}}
5661 ignore_target_hosts = 127.0.0.0/8
5664 This is the standard \%dnslookup%\ router, but with a modified setting of
5665 the \transport\ option. When the sender address is in your domain, it
5666 routes to the special transport instead of the standard one.
5668 The entire message is passed to your filter command on its standard
5669 input. It must write the modified version to the standard output, taking
5670 care not to break the RFC 2822 syntax. The command is run as the Exim
5673 There are a number of potential problems in doing this kind of
5674 modification in an MTA. Many people believe that to attempt is it wrong,
5677 1. It breaks digital signatures, which are becoming legally binding
5678 in some countries. It may well also break encryption.
5680 2. It is likely to break MIME encoding, that is, it is likely to wreck
5681 attachments, unless great care is taken. And what about the case of a
5682 message containing only binary MIME parts?
5684 3. It is illegal under German and Dutch law to change the body of
5685 a mail message in transit. It might potentially be illegal in
5686 the UK under European law. This consideration applies to ISPs and
5687 other ``common carriers''. It would presumably not apply in a corporate
5688 environment where modification was done only to messages originating
5689 from the employees, before they left the company's network. It might
5690 also not apply if the senders have explicitly given their consent
5691 (e.g. agreed to have advertisements added to their incoming mail).
5693 4. Since the delivered message body was produced by the MTA (not the
5694 originator, because it was modified), the MTA operator could
5695 potentially be sued for any content. This again applies to `common
5696 carrier' MTAs. It's interesting that adding a disclaimer of liability
5697 could be making you liable for the message, but this case seems
5698 more likely to involve adding advertisements than disclaimers. After
5699 all, no postal service in the world opens all the mail it carries to
5702 5. Some mail clients (old versions of MS outlook) crash if the message
5703 body of an incoming MIME message has been tampered with.
5705 There are also potential problems that could arise if a scheme to add
5706 disclaimers goes wrong for some messages:
5708 1. False negatives: `Ah, this guy usually says he does not represent
5709 their views, but in this message he doesn't have the disclaimer'.
5711 2. False positives: `This official announcement does not represent our
5714 An alternative approach to the disclaimer problem would be to insist
5715 that all relevant messages have the disclaimer appended by the MUA. The
5716 MTA should refuse to accept any that do not. Again, however, the MTA
5717 must understand the format of messages in order to do this. Simply
5718 checking for appropriate wording at the end of the body is not good
5719 enough. It would probably be necessary to run a Perl script from within
5720 an Exim system filter, or write a \^^local_scan()^^\ function in order
5721 to adopt this approach.
5723 Finally, it's a trivial matter to add customized headers of the sort:
5725 ==> X-Disclaimer: This is a standard disclaimer that says that the views
5726 X-Disclaimer: contained within this message are somebody else's.
5728 which is a much easier alternative to modifying message bodies.
5731 Q1602: How can I remove attachments from messages?
5733 A1602: The answer to this is essentially the same as for Q1601.
5737 17. ENCRYPTION (TLS/SSL)
5739 Q1701: I am trying to set up an Exim server that uses a self-signed certificate
5740 to enable my clients to use TLS. However, clients other than Exim
5741 refuse to accept this certificate. What's wrong?
5743 A1701: It seems that some clients require that the certificate presented by
5744 the server be a user (also called ``leaf'' or ``site'') certificate, and not
5745 a self-signed certificate. In this situation, the self-signed
5746 certificate must be installed on the client as a trusted root
5747 \*certification authority*\ (CA), and the certificate used by the server
5748 must be a user certificate signed with that self-signed certificate.
5750 For information on creating self-signed CA certificates and using them
5751 to sign user certificates, see the \*General implementation overview*\
5752 chapter of the Open-source PKI book, available online at
5753 \?http://ospkibook.sourceforge.net/?\. Here is a quick overview. First,
5756 \?http://www.FreeBSD.org/cgi/mid.cgi?id=3C3F3A93.C1ECF9B0%40mindspring.com?\
5758 Then, follow the instructions found on these two (consecutive) pages:
5760 \?http://ospkibook.sourceforge.net/docs/OSPKI-2.4.6/OSPKI/initialisation.htm?\
5761 \?http://ospkibook.sourceforge.net/docs/OSPKI-2.4.6/OSPKI/keygensign.htm?\
5763 Two points on the PKI Book literature:
5765 (1) It's assumed that it's okay to use a passphrase-protected key to
5766 encrypt the user/site/leaf certificate. If this isn't acceptable,
5767 you seem to be able to strip out the passphrase as follows:
5769 ==> openssl rsa -in user.key -our user.key.new
5772 This should be done immediately after \(user.key)\ is created.
5774 (2) The \*sign.sh*\ script is available in the \*mod_ssl*\ distribution,
5775 available at \?http://www.modssl.org/source/?\.
5777 Having followed the instructions, you end up with the following files:
5781 This file should be installed into the client software as a trusted
5782 root certification authority. In Windows XP, this can be done as follows:
5784 \#\#Call the file \(ca_cert.cer)\
5786 \#\#Double-click on the file
5788 \#\#"Install Certificate";
5792 \#\#"Place all certificates in the following store"
5796 \#\#"Trusted Root Certification Authorities"
5808 (b) \(user.crt)\ and \(user.key)\
5810 These files should be installed into the server software. In Exim, this
5811 can be done by adding these lines to the configuration file:
5813 ==> tls_certificate = /usr/local/etc/exim/tls_cert
5814 tls_privatekey = /usr/local/etc/exim/tls_key
5816 Then install \(user.crt)\ and \(user.key)\ under the names \(tls_cert)\
5817 and \(tls_key)\ in the appropriate directory.
5820 Q1702: How can I arrange for Exim to advertise support for SMTP authentication
5821 only when the session is encrypted?
5823 A1702: Use this setting:
5825 ==> auth_advertise_hosts = ${if eq{$tls_cipher}{}{}{*}}
5828 Q1703: I have some legacy clients that don't use STARTTLS, but which expect to
5829 negotiate a TLS session automatically on connection to the ssmtp port
5830 (465). Can Exim handle this?
5832 A1703: If you are using release 4.43 or later, you can set
5834 ==> tls_on_connect_ports = 465
5836 and then arrange for your daemon to listen on both port 25 and port 465
5837 by setting \daemon_smtp_ports\ or \local_interfaces\ or the \-X-\
5838 command line option. Or use \(inetd)\ to listen on port 465.
5840 If you are using an earlier release of Exim, you need to run two
5841 Exim listeners, on different ports, one of which is started with the
5842 \-tls-on-connect-\ option (which makes all ports act this way). You can
5843 either use two daemons, or a single daemon, with the other listener
5844 using \^inetd^\. For example, here are commands to start two daemons:
5847 exim -bd -oX '[0.0.0.0]::465' -tls-on-connect
5849 The first is a ``normal'' daemon; the second listens on port 465 and
5850 expects to negotiate a TLS session at the start of each connection.
5853 Q1704: When my Outlook Express 6.0 client sends a STARTTLS command to begin a
5854 TLS session, Exim doesn't seem to receive it.
5859 Q1705: I have listed some hosts in \tls_try_verify_hosts\, but when they
5860 connect, no data appears in \$tls_peerdn$\.
5862 A1705: This means that the clients have not sent certificates when asked by
5863 the server to do so. If the clients are running Exim, check that
5864 \tls_certificate\ is correctly set in their \%smtp%\ transports. Note
5865 that this value is not automatically inherited from the global
5866 \tls_certificate\ option.
5869 Q1706: I have listed some hosts in \tls_verify_hosts\ and provided them with
5870 certificates, but their connections are always rejected.
5872 A1706: Make sure that the server file containing the expected certificates
5873 (defined by \tls_verify_certificates\) is readable by the Exim user.
5874 See also the answer to Q1705.
5877 Q1707: I am trying to use TLS with Evolution as a client, and keep seeing this
5878 error: \*SMTP protocol violation: synchronization error (next input
5879 sent too soon): rejected "\200F^A^C".*\ What does it mean?
5881 A1707: See Q0086 for a general explanation of the error. In this case, it
5882 probably means that Evolution is trying to negotiate a TLS session
5883 immediately it connects, without first using the STARTTLS command. This
5884 was an older way of starting up TLS, before STARTTLS was defined. See
5885 Q1703 for how to deal with this.
5888 Q1708: I trying to use TLS with Outlook as a client on a box that is running
5889 Norton Antivirus, but all my email is being rejected with \*Unsupported
5890 command*\ errors. Why?
5892 A1708: Norton Antivirus does not support TLS or AUTH. It puts a broken SMTP
5893 proxy between you and the Exim server. You need to turn off outbound
5900 Q2000: Are there any Y2K issues with Exim?
5902 A2000: The author of Exim believes that it is Y2K-compliant, as long as the
5903 underlying operating system and C library are. Exim does not parse dates
5904 or times at all. Internally, it makes some use of binary timestamps in
5905 Unix format (number of seconds since 1-Jan-1970) and uses C library
5906 services to convert these to printing forms (e.g. for logging). The
5907 printing forms all use 4-digit years. Some people have tried various
5908 tests. No problems have been reported, but details of what tests have
5909 been done are not available.
5911 Well, it's now November 2001, and no Y2K problems have been reported, so
5912 it looks like I was right. This entry is retained as historical
5919 Q5001: How can I arrange to allow a limited set of users to perform a limited
5920 set of Exim administration functions? I don't want to put them all in
5923 A5001: See \?http://www.chiark.greenend.org.uk/~ian/userv/?\. Using \^userv^\ you can
5924 arrange (for example) for certain users to be able to invoke \^mailq^\ or
5925 \^runq^\ or other preset commands as \^exim^\ (or any other user, as configured)
5926 with only \^userv^\ configuration. If you want to check the particular Exim
5927 options available you can easily do it with shell or Perl scripts and
5928 \^userv^\ configuration, and provided you know how to do argument
5929 ``unparsing'' properly in shell or Perl it will be secure.
5932 Q5002: I want to ``tail'' the Exim log, but I have a number of other logs I also
5933 want to ``tail'', and the number of tailing windows is getting to be a
5936 A5002: Look for a program called \^xtail^\ (despite its name, it's not an
5937 X-windows application). It allows you to do multiple tails, even of
5940 Alternately, get the GNU version of \^tail^\, from the GNU textutils
5941 package (\?ftp://ftp.gnu.org/gnu/textutils/?\). GNU tail lets you run
5942 \"tail -f\" on multiple files at the same time, although it doesn't work
5943 on entire directories like \^xtail^\ can. If you are running Linux, you
5944 probably already have a version of GNU \^tail^\ that can follow multiple
5948 Q5003: How can I persuade Exim to accept ETRN commands without the leading
5951 A5003: Set the option
5953 ==> smtp_etrn_command = /usr/lib/sendmail -R $domain
5955 This causes Exim to run that command, with \$domain$\ replaced by the
5956 argument of ETRN. The default action of Exim is to require the # sign
5957 in order to be RFC-compliant, and to run the equivalent of
5959 ==> smtp_etrn_command = /usr/lib/sendmail -R ${substr_1:$domain}
5961 which uses the argument without the leading # as the value for the \-R-\
5962 option. You aren't restricted to running Exim with the \-R-\ option, of
5963 course. You can specify any command you like, with any number of
5964 arguments. In particular, you can pass over the IP address of the caller
5965 via \$sender_host_address$\. However, if you make use of expansion strings
5966 in the arguments, each one must be entirely contained in a single
5967 argument. For example, if you want to remove the first character of the
5968 ETRN argument when it is @ or #, you could use
5970 ==> smtp_etrn_command = "/usr/lib/sendmail -R \
5971 \"${if match {$domain}{^[@#]}{${substr_1:$domain}}{$domain}}\""
5973 The internal quotes are necessary because of the white space inside the
5977 Q5004: I've recently noticed that emails I send with a ::Bcc:: line are being
5978 delivered to their final destination with the ::Bcc:: line still present.
5980 A5004: Exim removes ::Bcc:: lines only if you call it with the \-t-\ option (i.e.
5981 when it is acting partly as an MUA). It does not remove ::Bcc:: lines that
5982 are present in incoming SMTP mail or command-line mail that does not
5983 use \-t-\. Indeed, it should not remove them, because only the
5984 initiating software (i.e. the MUA) can tell what to do with ::Bcc::
5985 lines; any MTA software has to leave them alone. This is what RFC 2822
5986 has to say about ::Bcc::
5988 \*The ::Bcc:: field (where the ``Bcc'' means ``Blind Carbon Copy'') contains
5989 addresses of recipients of the message whose addresses are not to be
5990 revealed to other recipients of the message. There are three ways in
5991 which the ::Bcc:: field is used. In the first case, when a message
5992 containing a ::Bcc:: field is prepared to be sent, the ::Bcc:: line is
5993 removed even though all of the recipients (including those specified
5994 in the ::Bcc:: field) are sent a copy of the message. In the second
5995 case, recipients specified in the ::To:: and ::Cc:: lines each are sent
5996 a copy of the message with the ::Bcc:: line removed as above, but the
5997 recipients on the ::Bcc:: line get a separate copy of the message
5998 containing a ::Bcc:: line. (When there are multiple recipient
5999 addresses in the ::Bcc:: field, some implementations actually send a
6000 separate copy of the message to each recipient with a ::Bcc::
6001 containing only the address of that particular recipient.) Finally,
6002 since a ::Bcc:: field may contain no addresses, a ::Bcc:: field can be
6003 sent without any addresses indicating to the recipients that blind
6004 copies were sent to someone. Which method to use with ::Bcc:: fields
6005 is implementation dependent, but refer to the ``Security
6006 Considerations'' section of this document for a discussion of each.*\
6009 Q5005: I used \^gv^\ 3.5.8 (\^ghostview^\) to try printing \(spec.ps)\. After every
6010 printed page, the printer ejects a blank sheet. Is this something to do
6011 with using ``letter'' rather than A4 paper?
6013 A5005: This seems to be an effect of using \^ghostview^\. Although the PostScript
6014 is generated for A4 pages, the size of the page images is such that they
6015 should fit on a letter page (they are shorter than would normally be
6016 used on A4 paper). If the PostScript file is sent directly to a
6017 PostScript printer, there is no problem. An alternative is to get hold
6018 of the \^psutils^\ toolset, which is available from
6019 \?ftp://ftp.dcs.ed.ac.uk/pub/psutils/psutils.tar.gz?\.
6020 It contains utilities for extracting pages (which can be useful for
6021 double-sided printing) and for resizing pages. If you resize from A4 to
6022 letter the text shrinks a bit, but should then be printable via
6026 Q5006: Why aren't there any man pages for Exim? I don't always carry my printed
6029 A5006: A single man page that lists the command line options is provided in
6030 file \(doc/exim.8)\ in the Exim distribution. Several other forms of
6031 online documentation are available. As well as plain ASCII text, the
6032 there are two forms - Texinfo and HTML - which have a certain amount of
6033 built-in indexing for ease of finding your way around. There are no man
6034 pages apart from the command line one because the author of Exim hasn't
6035 the time (or desire :-) to maintain yet another documentation format.
6036 Besides, it is hard to know how to split the Exim manual up.
6039 Q5007: When I send a message using the \-t-\ command line option, Exim sends only
6040 to the addresses within the message, not to those on the command line.
6042 A5007: There seems to be some confusion in the Sendmail community about the
6043 interpretation of recipient addresses on the command line if the \-t-\
6044 option is used. Some versions do one thing, and some another. Here is an
6045 except from one version of the Sendmail documentation for \-t-\:
6047 \*Read message for recipients. ::To::, ::Cc::, and ::Bcc:: lines will
6048 be scanned for recipient addresses. The ::Bcc:: line will be
6049 deleted before transmission. Any addresses in the argument
6050 list will be suppressed, that is, they will not receive
6051 copies even if listed in the message header.*\
6053 By default Exim follows this specification, and interprets addresses on
6054 the command line as addresses not to send to. You can set
6056 ==> extract_addresses_remove_arguments = false
6058 to change this behaviour so that command line addresses are added to the
6059 addresses that are taken from the header lines.
6062 Q5008: If I set up a domain list to contain //*customer.com//, it matches
6063 //customer.com// and //abc.customer.com// as required, but it also matches
6064 //noncustomer.com//, which is wrong. How can I get round this?
6066 A5008: You have to specify two entries in the list:
6068 ==> customer.com : *.customer.com
6070 because * in a domain list matches any characters, including \"."\ and
6071 including a null sequence.
6074 Q5009: I want to match all domains of the form //*.oyoy.org// but want a few
6075 exceptions. For instance I don't want //foo.oyoy.org// or //bar.oyoy.org// to be
6076 included. What is the best way to do this?
6078 A5009: Use negative items in the domain list, like this:
6080 ==> domainlist local_domains = !foo.oyoy.org : !bar.oyoy.org : *.oyoy.org
6082 If there are many exceptions, you can use a lookup instead of listing
6083 them all inline. If there are a number of exceptions that match a
6084 particular pattern, you could use a regular expression.
6087 Q5010: I can't seem to find a pre-built version of Exim anywhere. The machine
6088 is a Sparc 5 running Solaris 2.6.
6090 A5010: The primary distribution is source-only. However, some people have built
6091 and distributed RPMs and debs for Linux systems, and ports for FreeBSD.
6092 I haven't heard of anyone doing this for Solaris. The main problem with
6093 binary distributions is that there are a number of build-time options,
6094 requiring the answers to questions like:
6096 . Which DBM library do you have? (On Solaris probably ndbm, but no easy
6097 default on some other systems.)
6099 . Which uid/gid do you want to use for Exim?
6101 . Where do you want the configuration file to be? (Many different
6102 answers, even on the same OS, depending on local policy.)
6104 . Ditto for the binaries.
6106 . Which optional bits of Exim do you want to include?
6109 Q5011: Is there a version of Exim available that runs under Windows?
6111 A5011: A long time ago somebody took a copy of the Exim source with the aim of
6112 trying to port it to Windows NT. However, I never heard anything more.
6113 However, current versions of Exim can be made to run under Cygwin.
6116 Q5012: Does Exim support Delivery Status Notification (DSN), Message Status
6117 Notification (MSN), or any other form of delivery acknowledgement?
6122 Q5013: What does ``Exim'' stand for?
6124 A5013: Originally, it was ``EXperimental Internet Mailer'', which was the best I
6125 could come up with when I was starting out. At that point it was
6126 experimental - I wanted to see if the ideas I had for extending Smail's
6127 approach actually worked. Then somebody discovered about it and wanted
6128 to start using it, and told other people about it...
6131 Q5014: Although I haven't set \check_spool_space\, Exim is still checking the
6132 amount of space on the spool for incoming SMTP messages that use the
6133 SIZE option. Can I suppress this?
6135 A5014: The RFC for the SIZE option says:
6137 \*If the server currently lacks sufficient resources to accept a
6138 message of the indicated size, but may be able to accept the
6139 message at a later time, it responds with code ``452
6140 insufficient system storage''.*\
6142 and that is what Exim is trying to implement. This is entirely
6143 independent from \check_spool_space\, which says \*don't accept any mail
6144 if there is less than so much space in the spool partition*\, though the
6145 code is optimised to do both checks at the same time if required.
6146 However, you can suppress the SIZE check if you want to, by unsetting
6147 \smtp_check_spool_space\.
6150 Q5015: I just noticed log entries that start off \"<= <>"\. Am I correct in
6151 assuming that the \"<>"\ indicates that the envelope did not contain any
6154 A5015: Yes. This indicates a delivery failure report (aka a ``bounce message''),
6155 as specified in RFC 2821. The reason for using empty sender addresses is
6156 to identify bounce messages so that they themselves do not cause further
6157 bounces. Empty senders are also used for other kinds of report which
6158 should not themselves cause the generation of bounce messages. For
6159 example, Exim uses them when sending out warnings about delivery delays.
6162 Q5016: I've received a message which does not have my address in the ::To::
6163 line. It is a spam message with the same address in both the ::From:: and
6164 the ::To:: headers. How can this happen, and why doesn't Exim reject it?
6166 A5016: There is an important distinction between the ``envelope'' from and to and
6167 the ``header'' from and to. The former are sometimes called the ``sender''
6168 and ``recipient''. An email message needs an ``envelope'' for the same
6169 reason that paper mail does - the envelope tells the delivery mechanism
6170 what to do with this copy of the message, whereas the ::To:: header lists
6171 all the recipients, including those who have been sent different copies
6172 of the message because their mailbox is on some other host.
6174 An MTA such as Exim works entirely with the ``envelope'' addresses, not
6175 with those in the header lines. Don't try to block mail where envelope
6176 from and the header from differ. There are common legitimate cases where
6177 this happens, for example, messages forwarded from mailing lists and
6178 delivery failure reports.
6181 Q5017: Can (or will) Exim ever handle a message delivery purely in memory,
6182 that is, it is handled without it ever hitting the disk?
6184 A5017: It doesn't, and never will. Accepting and delivering a message are two
6185 entirely separate, independent processes, which communicate only by
6186 writing/reading the message on the disk.
6189 Q5018: If I am using dbm files for data that Exim reads, can I rebuild them
6190 on the fly, or do I need to restart Exim every time I make a change?
6192 A5018: Exim re-reads the file every time it consults it, so if you are using a
6193 cdb or a DBM library that uses just a single file (i.e. not ndbm),
6194 you can just build the new file with a temporary file name, and use
6195 \^mv^\ to rename it into the correct place on the fly. If there are two
6196 files to rename, there is a window of time during which the DBM database
6197 is inconsistent. On lightly loaded systems this may not matter.
6200 Q5019: I need an option that is the opposite of \-bpa-\, that is, a listing of
6201 those addresses generated from a top-level address that have not yet
6204 A5019: Exim does not keep this information. It saves only the top-level
6205 addresses and the list of addresses that are finished with. At each
6206 delivery attempt, generated addresses are recomputed from scratch. This
6207 makes it possible to correct errors in redirection data that is
6208 causing delivery delays. However, there is an option you can set on a
6209 \redirect\ router that changes things. It is called \one_time\, and if
6210 it is set, the list of generated addresses gets added to the top-level
6211 list at the first delivery attempt, and is never regenerated. Because
6212 top-level address lists must be real email addresses, this option cannot
6213 be used if any of the generated addresses are pipes, files, or
6217 Q5020: How can I make Exim receive incoming mail, queue it, but not attempt to
6218 deliver it? I want to be in this state while moving some mailboxes.
6220 A5020: Set \queue_only\ in the Exim configuration. Then kill your daemon,
6221 and restart it without the \-q-\ option (i.e. with just the \-bd-\ option),
6222 so that it does not spawn any queue runners. This stops all deliveries,
6223 remote as well as local.
6226 Q5021: What does Exim use for POP and IMAP as a default? Do I have to install
6229 A5021: Yes. Exim provides MTA functionality. That is, it delivers mail. POP and
6230 IMAP are two of several ways of reading previously-delivered mail. Exim
6231 does not provide that functionality. You need to install POP and/or IMAP
6232 daemons; there are several to choose from.
6235 Q5022: Is there an easy way of removing all queued messages at once in a safe
6238 A5022: Try this command:
6240 ==> exim -bp | awk '/^ *[0-9]+[mhd]/{print "exim -Mrm " $3}' | sh
6243 Q5023: Why does Exim do \*ident*\ callbacks by default? Isn't this just a waste
6244 of resources? I've been told this is an ancient way of authentication.
6247 A5023: This is a common misunderstanding, at least partially resulting from the
6248 incorrect naming of the protocol when it was first published.
6249 The service on port 113 is an identification service, which allows a
6250 target host to record information identifying the user responsible for
6251 making a connection to it. The information may not be intelligible to
6252 the recording host - it could, for example, be encrypted so that only
6253 someone on the calling host can make sense of it. It is useful for
6254 providing additional information in an audit trail.
6256 At least one site has found \^ident^\ effective against two rather
6257 prevalent kinds of open proxy (whether already blacklisted at the RBLs
6258 or not). An ACL statement is used to reject mail from servers that
6259 return \^ident^\ strings of \"squid"\ and \"CacheFlow Server"\.
6260 Snippets such as this in the RCPT ACL do the trick:
6262 ==> deny condition = ${if eq{$sender_ident}{CacheFlow Server}{1}{0}}
6263 message = Rejected - appears to be an unsecured proxy: $sender_ident
6265 The likelihood that a genuine mail process would return those specific
6266 ident strings is vanishingly small.
6268 The \^ident^\ data should not be used for authentication in any form
6269 except on a closed secure network between cooperating hosts (probably
6270 not even then). The information from the source host is only as reliable
6271 as the host itself. If it's not under your control then you have to
6272 treat the information as opaque data that can be used only by the
6273 sysadmin of the source system to trace back connection data. Some
6274 \^ident^\ implementations send out opaque cookies or DES encrypted
6275 information. \^Ident^\ is hugely useful at times - especially for
6276 checking back on connections from multiuser machines (as opposed to
6277 one-person desktop boxes).
6279 You can stop Exim making ident calls by adding
6281 ==> rfc1413_query_timeout = 0s
6283 to its configuration, but it is better to leave it active (reducing the
6284 timeout to 10s or less if it is causing problems) - it costs very
6285 little, and in cases of mail forgery from a multiuser system can track
6286 the sinner concerned very quickly.
6289 Q5024: I often have the problem that a message gets stuck in the mail queue and
6290 I want it to be bounced to a certain address.
6292 A5024: You can do this using a combination of four command line options, like
6295 ==> exim -Mf 14Fdlq-0003kM-00
6296 exim -Mmad 14Fdlq-0003kM-00
6297 exim -Mar 14Fdlq-0003kM-00 new@ddress
6298 exim -M 14Fdlq-0003kM-00
6300 The first command freezes the message so that a queue runner won't start
6301 to deliver it while you are changing things. The second command marks
6302 all existing recipients as delivered. The third command adds a new
6303 recipient, and the fourth command forces a delivery of the message,
6304 which will cause it to be delivered to the new address, and then
6308 Q5025: What precautions should I take when editing Exim's run time
6311 A5025: Edit the file and save the result in a new file. Test the syntax of
6312 the new file by running a command like this:
6314 ==> exim -bV -C exim.conf.new
6316 That will check for syntax errors without disturbing your running
6317 configuration. If you are paranoid enough, run, as \/root/\,
6319 ==> exim -C exim.conf.new <some address>
6323 and see if it delivers it. Carry on testing until happy. When happy,
6325 ==> mv exim.conf.new exim.conf
6326 kill -HUP `cat /var/spool/exim/exim-daemon.pid`
6328 Then check the Exim log to be sure the daemon restarted OK. Watch the
6329 log for a bit to see that mail is flowing.
6332 Q5026: Is exim able to use RFC 2645, \*On-demand Mail Relay*\ (ODMR)?
6337 Q5027: Is there any way I can send bounces to the postmaster, and nobody else?
6338 Basically, I want to receive them, and I don't want the reply/from
6339 person to get them. If I think they need it I will forward it myself.
6341 A5027: Put \"errors_to=postmaster"\ on every router.
6344 Q5028: When I HUP the Exim daemon, the name shown in the process table changes
6345 from \(/usr/lib/sendmail)\ (which is a symlink) to the real binary name.
6348 A5028: Add this to your Exim configuration:
6350 ==> exim_path = /usr/lib/sendmail
6353 Q5029: A message with a recipient address that contains a non-printing character
6354 is stuck on my mail queue. How can I remove this address?
6356 A5029: You can use the \-Mmd-\ command line option to mark a recipient address
6357 ``delivered'', which effectively removes it. If you are using the Bash
6358 shell, you can enter non-printing characters using an escape sequence.
6361 ==> exim -Mmd 15HKvU-00013Q-00 $'\240'abc@x.y.z
6363 In this example, the first character of the local part has a code value
6364 of 240. If you are using a shell that does not support this, create the
6365 command in a file and run it as a shell script.
6368 Q5030: I am using exim in a two queues scenario, with two different
6369 configuration files. How can I run a second copy of \^eximon^\ to
6370 inspect and modify the alternate queue?
6372 A5030: Use these commands (or put them in a script):
6374 ==> EXIMON_EXIM_CONFIG=/your/path/exim/configure.alternate
6375 export EXIMON_EXIM_CONFIG
6376 /your/path/exim/bin/eximon
6379 Q5031: Why is there no sender address on bounce messages? It shows up as "<>".
6381 A5031: See the answer to Q0042.
6384 Q5032: Are there any Exim web-based administration scripts?
6386 A5032: No (as far as is known). It seems likely that producing one that is
6387 generic enough would be a difficult task.
6390 Q5033: How can I send a copy of all outgoing messages to another mailbox?
6392 A5033: The most straightforward way is to set up a system filter, and include
6395 ==> unseen deliver mailbox@whatever.domain
6397 This sends a copy of every message to //mailbox@whatever.domain//
6398 (unless the message already has that recipient - Exim never does
6399 duplicate deliveries).
6401 To save only ``outgoing'' messages, you need to come up with a
6402 definition of what ``outgoing'' means. Typically, this might be a check
6403 on the sender address and/or on the originating host. Here is an
6406 ==> if $sender_address_domain is mydomain.com and
6407 ${mask:$sender_host_address/24} is 192.168.324.0/24
6409 unseen deliver mailbox@whatever.domain
6413 Q5034: Is there any way to make the \queue_only\ option conditional? I would
6414 like the ability to queue messages from external sources while deliver
6415 locally generated email as normal.
6417 A5034: There is no direct way of doing this. However, you can achieve the
6418 effect. In one of your ACLs that checks incoming mail from external
6421 ==> warn control = queue_only
6423 You can add other conditions as well, of course.
6426 Q5035: Does Exim run with different permissions between \-bt-\ and \-bh-\, or
6427 between verifying and actual sending?
6429 A5035: Yes. For \-bt-\ it runs as root, as it would when delivering a message.
6430 For \-bh-\, \-bv-\, and when actually receiving a message, it runs as
6437 Q9101: How can I install Exim on Mac OS X?
6439 A9101: (1) There is useful advice on this web page:
6440 \?http://www.afp548.com/Articles/Jaguar/exim410.html?\.
6442 (2) There is a package installer available at this URL:
6443 \?ftp://members.aol.com/AFP548dotcom/EximInstaller.sit?\.
6445 (3) There is another package installer for the combination of MySQL,
6446 Exim, Exiscan, CourierIMAP, and SpamAssassin at this URL:
6447 \?http://maxo.captainnet.net/installs/mail-install.html?\.
6453 Q9201: On FreeBSD, \(/usr/sbin/sendmail)\ is a symbolic link to
6454 \(/usr/sbin/mailwrapper)\; it doesn't contain the Sendmail binary. How
6455 should I replace Sendmail with Exim on FreeBSD?
6457 A9201: There is a file called \(/etc/mail/mailer.conf)\ which selects what to
6458 run for various MTA calls. Instead of changing \(/usr/sbin/sendmail)\,
6459 you should edit this file instead, to read something like this:
6461 ==> sendmail /usr/exim/bin/exim
6462 send-mail /usr/exim/bin/exim
6463 mailq /usr/exim/bin/exim -bp
6464 newaliases /usr/bin/true
6466 You probably also need to edit \(/etc/periodic.conf)\; see Q9202.
6469 Q9202: A script that FreeBSD runs nightly uses \^mailq^\ with the \-Ac-\
6470 parameter. Why doesn't Exim recognize this?
6472 A9202: \-Ac-\ is a Sendmail option that requests that mailq ``Show the mail
6473 submission queue specified in \(/etc/mail/submit.cf)\ instead of the
6474 MTA queue specified in \(/etc/mail/sendmail.cf)\''. Exim doesn't have
6475 the concept of a ``submission queue''. You can disable this feature
6476 of the nightly script by adding the line
6478 ==> daily_status_include_submit_mailq="NO" # No separate 'submit' queue
6480 to the file \(/etc/periodic.conf)\.
6483 Q9203: How can I use Exim for authenticated SMTP using Cyrus on FreeBSD?
6485 A9203: This web page may help: \?http://www.munk.nu/exim/exim-freebsd-asmtp.php?\.
6491 Q9301: I'm trying to compile on an HP machine and I don't have \^gcc^\ there. So I
6492 put \"CC=cc"\ in the \(Local/Makefile)\, but I got this error:
6494 ==> (Bundled) cc: "buildconfig.c", line 54: error 1705: Function prototypes
6495 are an ANSI feature.
6497 A9301: The bundled compiler is not an ANSI C compiler. You either have to get a
6498 copy of \^gcc^\ from the HPUX Software Porting Archives or buy the ANSI cc
6499 from HP. The advice given by one user of HP systems on the Exim
6500 mailing list was as follows:
6502 \*Personally, I wouldn't use anything but the ANSI C compiler. gcc
6503 works for compilation, but it doesn't know squat about PA-RISC chips
6504 past the 1.0 rev. Since then, HP has come out with PA-RISC 1.1, 2.0,
6505 and 2.1, each with better features. gcc will compile for them, but it
6506 doesn't produce anywhere near the optimization that HP's compiler
6509 \*I took the gcc road when we moved from FreeBSD to HP-UX because I was
6510 familiar with it. After 6 months, I had to go and re-port everything
6511 over when we realized that gcc wasn't going to do it for us long-term.
6512 If I could give advice to any new HP-UX admin: don't use gcc if you
6513 can afford the ANSI C compiler. Based on the cost of even the lowest
6514 HP workstation, that usually isn't a problem.*\
6520 Q9401: On BSDI 4.0, Exim built with Perl support exits with the error message
6522 ==> ./exim: can't load library 'libperl.so'
6524 A9401: You probably compiled perl5 yourself, without looking into
6526 ==> /usr/src/contrib/perl5/perl5.004_02/hints/bsdos.sh
6528 first. The problem is that the command
6530 ==> perl5 -MExtUtils::Embed -e ldopts
6532 doesn't give you sufficient flags to link something with libperl.
6533 Since 5.004_02 the \(hints/bsdos.sh)\ file has changed to adapt to the
6534 changes between BSDI 3.1 and 4.0, but it is still not entirely right.
6536 The solution is, when you compile perl, change the \ccdlflags\
6537 variable in config.sh to:
6539 ==> -rdynamic -Wl,-rpath,/usr/local/lib/perl5/5.00502/i386-bsdos/CORE
6541 (or something similar). Alternatively, you can run \(./Configure)\ and
6542 answering the question \*Any special flags to pass to cc to use dynamic
6543 loading?*\ with the above line. It is not known what \-rdynamic-\ means
6544 (it's not apparently documented in any man page), but that's what BSDI
6545 guys did to compile perl5 which comes with BSDI 4.0 distribution.
6551 Q9501: The IP addresses for incoming calls are all being given as
6552 255.255.255.255 or 0.0.0.0.
6554 A9501: This problem should no longer occur because a workaround has been
6561 Q9601: Exim is mysteriously crashing, usually when forking to send a delivery
6564 A9601: This has been seen in cases where Exim has been incorrectly built with
6565 a muddled combination of an \(ndbm.h)\ include file and a non-matching
6568 Faults like this have also been seen on systems with faulty motherboards.
6569 You could try to compile the Linux kernel 10 times - if the compile
6570 process stops with signal 11, your hardware is to blame.
6573 Q9602: I want to use \^logrotate^\ which is standard with RH5.2 Linux to rotate
6574 my mail logs. Anyone worked out the \^logrotate^\ config file that will
6577 A9602: Here's one suggestion:
6579 ==> /var/log/exim/main.log {
6580 create 644 exim exim
6586 The sleep is added to allow things to close the log file prior to
6587 compression. You also need similar entries for the panic log and the
6588 reject log, of course.
6591 Q9603: I'm seeing the message \*inetd[334]: imap/tcp server failing (looping),
6592 service terminated*\ on a RedHat 5.2 system, causing \^imap^\ connections to
6593 be refused. The \^imapd^\ in use is Washington Univers 12.250. Could this
6594 be anything to do with Exim?
6596 A9603: No, it's nothing to do with Exim, but here's the answer anyway: there
6597 is a maximum connection rate for \^inetd^\. If connections come in faster
6598 than that, it thinks a caller is looping. The default setting on RedHat
6599 5.2 is 40 calls in any one minute before \^inetd^\ thinks there's a problem
6600 and suspends further calls for 10 mins. This default setting is very
6601 conservative. You should probably increase it by a factor of 10 or 20.
6604 ==> imap stream tcp nowait.400 root /usr/sbin/tcpd /usr/local/etc/imapd
6606 The rate setting is the number following ``nowait''. This syntax seems to
6607 be specific to the Linux version of \^inetd^\. Other operating systems
6608 provide similar functionality, but in different ways.
6611 Q9604: I get the \*too many open files*\ error especially when a lot of messages
6612 land for Majordomo at the same time.
6614 A9604: The problem appears to be the number of open files the system can
6615 handle. This is changable by using the proc filesystem. To your
6616 \(/etc/rc.d/rc.local)\ file append something like the following:
6618 ==> # Now System is up, Modify kernel parameters for max open etc.
6620 ==> if [ -f /proc/sys/kernel/file-max ]; then
6621 echo 16384 >> /proc/sys/kernel/file-max
6623 if [ -f /proc/sys/kernel/inode-max ]; then
6624 echo 24576 >> /proc/sys/kernel/inode-max
6626 if [ -f /proc/sys/kernel/file-nr ]; then
6627 echo 2160 >> /proc/sys/kernel/file-nr
6630 By echoing the value you want for file-max to the file \(file-max)\ etc.,
6631 you actually change the kernel parameters.
6634 Q9605: I installed debian 2.2 linux on a small 325mb 486 laptop. When I try
6635 to test the Mail program, I get the following error: \*Failed to open
6636 configuration file /etc/exim.conf*\.
6638 A9605: The Debian installation should have given you \(/usr/sbin/eximconfig)\,
6639 which asks you some questions and then sets up the configuration file
6640 in \(/etc/exim.conf)\. Try running that (you'll probably need \/root/\) and see
6641 how it goes. In any case you get a thoroughly commented conf file at
6642 the end, which will give you a sample from which to work if you need
6643 further modification.
6645 The Exim docs in the Debian package are in \(/usr/doc/exim)\ where the full
6646 reference manual is \(spec.txt.gz)\.
6649 Q9606: I'm having trouble configuring Exim 4 on a Debian system. How does
6650 \(/etc/exim4/conf.d)\ work?
6652 A9606: The Debian Exim 4 package uses a quite uncommon, but elegant,
6653 method of configuration where the ``real'' Exim configuration file is
6654 assembled from a tree of snippets by a script invoked just before the
6655 daemon is started (see Q9608).
6657 This fits very well into the Debian system of configuration file
6658 management and is a great ease for the automatic configuration with
6659 Debconf. However, it is very different from the normal way Exim 4 is
6660 configured. Non-Debian users on the Exim mailing list will probably have
6661 difficulty in trying to answer specific questions about it. You may have
6662 to find a Debian expert.
6665 Q9607: I'm having difficulties trying to make Exim 4 with Redhat 9 and Berkeley
6668 A9607: Have you remembered to install the db4-devel package?
6671 Q9608: I'm running Exim 3 under Debian, and want to upgrade to Exim 4. How
6674 A9608: A user who did this, using the Debian Exim 4 package, reported as
6677 (1) The exim4 package installs easily, and the exim (3.38) package
6678 uninstalls at the same time.
6680 (2) Exim runs from \^inetd^\. Exim4 runs from \^/etc/init.d^\. Much nicer!
6682 (3) The exim conffile lives in \(/etc/exim/exim.conf)\. The exim4 conffile
6683 lives in \(/var/lib/exim4/config.autogenerated)\. It is, as the name
6684 suggests, autogenerated.
6686 (4) A new directory is created called \(/etc/exim4)\. This contains the
6687 conffiles to generate the above config. You make changes here.
6689 (5) Once you have made changes to the files in \(/etc/exim4)\ you run the
6690 script \^update-exim4.conf^\ which generates a replacement
6691 \(config.autogenerated)\.
6693 [Added comment by the Debian maintainer, slightly edited:
6694 You also need to tell the Exim daemon to reread the changed
6695 configuration. You can do this using SIGHUP by hand. Alternatively,
6696 instead of running \^update-exim4.conf^\ you can use
6698 ==> invoke-rc.d exim4 reload
6700 which does the rebuild and also tells Exim to reread the changed
6703 (6) In my experience, you need to carefully check the generated
6704 configs. eg, it did not generate a system filter file reference in the
6705 \(config.autogenerated)\. I didn't bother too much, since this is a home
6708 (7) All of this may be in the docs. I've read some of them, obviously,
6709 but didn't come across an actual upgrade guide.
6711 [The Debian maintainer says:
6712 \(/usr/share/doc/exim4-base/README.Debian.gz)\ and \^update-exim4.conf(8)^\
6713 should answer most of the questions.]
6715 (8) I've still got some minor things to tweak to get back to where I
6716 was before with Exim 3. But overall, it's no drama.
6719 Q9609: Why do some servers refuse SMTP connections from my Linux box, but accept
6720 connections from hosts running other operating systems?
6722 A9609: If you are sure this isn't a policy issue (that is, your box isn't
6723 administratively blocked for some reason), this may be because your
6724 Linux box has ECN (Explicit Congestion Notification) enabled in its
6725 TCP/IP stack. There are many broken firewalls that refuse connections
6726 from ECN-enabled hosts. You can check the state of your box by running
6728 ==> cat /proc/sys/net/ipv4/tcp_ecn
6730 If the value is "1", you have ECN enabled. You can turn it off by
6731 running this command:
6733 ==> echo "0" > /proc/sys/net/ipv4/tcp_ecn
6739 Q9701: Exim builds fine with \^gcc^\ on SunOS 4 but crashes inside \^^sscanf()^^\.
6741 A9701: Make sure you are linking with the GNU \^ld^\ linker and not the system
6745 Q9702: How can I get rid of spurious \"^M"\ (carriage return) characters in
6746 messages sent from CDE \^dtmail^\?
6748 A9702: CDE \^dtmail^\ passes messages to Exim via the command line interface with
6749 lines terminated by CRLF, instead of the Unix convention of just LF.
6750 This should not be a problem if you are using Exim release 4.21 or
6751 later, as changes were made to detect CRLF line endings.
6753 In earlier versions of Exim, CR would be treated as just another data
6754 character. There was, however, a command line option called
6755 \-dropcr-\ which caused Exim to ignore all CR characters in an incoming
6756 non-SMTP message. (This option is a no-op in current releases.)
6758 If you are using a pre-4.21 version of Exim, you should configure
6759 \^dtmail^\ to add this option to the command it uses to call Exim (using
6760 the path \(/usr/lib/sendmail)\). However, it has been reported that it
6761 isn't possible to change this call from \^dtmail^\ by any official
6762 means. An alternative approach is to replace \(/usr/lib/sendmail)\ by a
6763 filtering script that removes the spurious CRs from the input before
6767 Q9703: On SunOS 4 Exim crashes when looking up domains in the DNS that have
6768 more than 10 A records.
6770 A9703: There are Sun library patches to fix this. It is not Exim's problem.
6771 For 4.13_U1 the patch is 101558-xx; for 4.1.3 the patch is 100891-xx.
6772 From the README: \*1054748 ftp, ping dump core when connecting to a host
6773 with multiple DNS A records.*\ An alternative is to build another
6774 resolver library - such as the ones that are part of the \^bind^\
6775 distribution - and explicitly link against those.
6778 Q9704: I am experiencing mailbox locking problems with Sun's \^mailtool^\ used
6781 A9704: Under the \"Expert"\ settings of \^mailtool^\ is a option to turn on \*Use
6782 network aware mail file locking*\. By default \^dtmail^\ has this set, but
6783 \^mailtool^\ doesn't. You should set it. The help info on \^dtmail^\ has this
6786 \*Mailer tries to prevent two different instances of itself from opening
6787 the same mail file at the same time through a technique that detects
6788 this access when both instances of Mailer and the file are all on the
6789 same machine. A network-aware mail file locking protocol is available
6790 that uses ToolTalk to coordinate instances of Mailer running from more
6791 than one machine, or mail files accessed over the network. Mailer can
6792 only change this option when first opening a mail file.*\
6794 If you are using the SunOS4 version of \^mailtool^\, this apparently
6795 doesn't work. The only thing which does seem to work it getting the user
6796 to hit the \"done"\ button to make it release the lock.
6799 Q9705: Exim has been crashing on my Solaris x86 system, apparently while
6800 running DBM functions.
6802 A9705: The use of \^ndbm^\ with \^gcc^\ has caused problems on x86 Solaris systems.
6803 Try changing one or the other; using either DB with gcc, or Sun's
6804 WS compiler with \^ndbm^\, has fixed this in the past.
6807 Q9706: The \^exiwhat^\ utility isn't working for me on a Solaris 2 system.
6809 A9706: Have you got \(/usr/ucb)\ on your path? If so, it is probably picking up the
6810 wrong version of the \^ps^\ command. The \^exiwhat^\ script is built on
6811 Solaris to expect the normal Solaris version of \^ps^\.
6814 Q9707: How do I stop Sun's \^dtcm^\ from hanging?
6816 A9707: From qmail's FAQ: \*There is a novice programming error in dtcm, known as
6817 ``failure to close the output side of the pipe in the child.'' Sun has,
6818 at the time of this writing, not yet provided a patch.*\
6821 Q9708: I want Exim to use only the resolver (i.e. ignore \(/etc/hosts)\), but don't
6822 want to alter the \(nsswitch.conf)\ file in Solaris 2.
6824 A9708: You need to rebuild Exim after fiddling with \(OS/os.h-SunOS5)\:
6826 ==> #define gethostbyaddr res_gethostbyaddr
6827 #define gethostbyname res_gethostbyname
6828 #define endhostent res_endhostent
6829 #define endnetent res_endnetent
6830 #define gethostent res_gethostent
6831 #define getnetbyaddr res_getnetbyaddr
6832 #define getnetbyname res_getnetbyname
6833 #define getnetent res_getnetent
6834 #define sethostent res_sethostent
6835 #define setnetent res_setnetent
6837 Note that \-lnsl-\ is still needed in the Makefile as it
6838 contains code used by the NIS lookup and also the \^^inet_addr()^^\ function
6842 Q9709: When I try to compile Exim 4.x on Solaris 2.5.1 I get an error along the
6843 lines of \*no such field in struct as 'value.ui32'*\.
6845 A9709: Look in the Exim file \(OS/os.h-SunOS5.h)\ for the line
6847 ==> #define LOAD_AVG_FIELD value.ui32
6849 and change \"ui32"\ to \"ul"\ (that's u followed by the letter ell, not
6850 the digit one). Solaris 2.5.1 is getting very old now...
6854 98. CONFIGURATION COOKBOOK
6856 Q9801: How do I configure Exim as part of TPC (\?http://www.tpc.int?\)?
6858 A9801: Suppose you want to accept faxes destined for 1(801)539-*. These are
6859 addressed to the domain //9.3.5.1.0.8.1.tpc.int//. Set up a transport to
6860 handle the delivery:
6864 command = /usr/local/tpc/tpcmailer.pl $local_part@$domain \
6868 \(/usr/local/tpc/tpcmailer.pl)\ is the mail processing script that can
6869 be obtained from the TPC distribution. Create a router to route mail
6870 for the TPC domain to that transport. This must be placed before your
6876 domains = *.9.3.5.1.0.8.1.tpc.int
6878 Of course, there are other things to do as well before your system is
6879 a functioning TPC server.
6882 Q9802: How do I configure Exim so that it sends mail to the outside world only
6883 from a restricted list of our local users?
6885 A9802: You will need to have a convenient way of checking the list. If it is
6886 only a handful of users, you could just list them inline. Otherwise, you
6887 need to put them in a file or database. Let's suppose you've just got a
6888 list in a file. Put this as your first router:
6892 domains = ! +local_domains
6893 senders = ! : ! lsearch;/etc/permitted/senders
6895 data = :fail: you are not allowed to send outside
6897 The senders should be listed as complete addresses, with both a local
6898 part and a domain. For a large list, use a DBM or cdb file instead, or
6899 a database. The first item in the \senders\ list is empty, to match the
6900 empty sender. This is necessary because bounce messages have null
6904 Q9803: A site for which I provide secondary MX is down for some time. Is there
6905 a way to run the queue for that destination separately from the main
6908 A9803: No, because Exim does not have the concept of ``the queue for that
6909 destination''. It simply has a single pool of messages awaiting delivery
6910 (and some of them may have several destinations). The best approach to
6911 this is to arrange for all messages for the site to be saved somewhere
6912 other than the main spool, either on a separate dedicated MTA, or in
6916 Q9804: We want to be able to temporarily lock out a user by disabling the
6917 password and moving the home directory to another place. How can we
6918 arrange to reject mail for users in this state?
6920 A9804: Change the home directory pointer in the passwd file to something
6921 distinctive. For example, we use \(/home/CANCELLED)\ for cancelled users.
6922 Then you can pick up such users with this router, which is placed
6923 immediately after \%system_aliases%\:
6925 ==> cancelled_users:
6928 condition = ${if eq {$home}{/home/CANCELLED}{yes}{no}}
6930 data = :fail: this account is cancelled
6933 Q9805: How can I configure Exim so that all mails addressed to
6934 //something@username.domain.net// get delivered to
6935 \(/var/spool/mail/username)\?
6937 A9805: Assuming that you have set up //username// as a normal user, with
6938 conventional routing for //username@domain.net// to that mailbox, all
6939 you need to do is set up a redirection, using a router like this:
6943 data = ${if match{$domain}{\N^(.*)\.domain\.net$\N}\
6944 {$1}fail}@domain.net
6946 If you set \envelope_to\ in the \%appendfile%\ transport, the original
6947 envelope address is preserved in the message in an ::Envelope-to::
6951 Q9806: How do I get exim not to add a ::Sender:: header to locally originated
6954 A9806: It adds it only if the ::From:: header doesn't correspond to the user
6955 sending the message. You can suppress this by setting
6956 \no_local_from_check\. If your real question is \*How do I submit mail
6957 from UUCP without it adding ::Sender::?*\, see Q1503.
6960 Q9807: Is there any way to have messages sent to a specific local address
6961 delayed by - say - 24 hours?
6963 A9807: Set up a router like this:
6967 domains = the.domain
6968 local_parts = thelocalpart
6969 condition = ${if < {$message_age}{86400}{yes}{no}}
6971 data = :defer: message not old enough
6974 Of course, this will also have the effect of setting a retry time for
6975 the address. You may want to set a special retry rule for it. Note the
6976 use of \no_verify\ to ensure that this router is not used when Exim is
6977 verifying addresses.
6980 Q9808: I have a mailing list exploder on one host, and three other hosts where
6981 I want to do the actual deliveries from. How can I get Exim to split
6982 a message into groups of recipients between the three hosts?
6984 A9808: Set up a router that routes all remote addresses to a specific
6985 transport, with a list of your three hosts. For example:
6988 driver = manualroute
6989 transport = to_three_smtp
6990 route_list = !+local_domains hostA:hostB:hostC
6992 The transport looks like this:
6998 By setting \hosts_randomize\, you request that the host list be sorted
6999 randomly each time the transport is called, in order to spread the load.
7000 The number of times the transport is called for each message depends on
7001 the setting of the global option \remote_max_parallel\. If it is set to
7002 1, the transport is called only once for each message, so only one host
7003 is used, but different messages use different hosts because of the
7006 The \max_rcpt\ option (default 100) controls the number of addresses
7007 sent in each copy of the message - several copies are sent over the
7008 same connection if necessary.
7010 If you want individual messages to be split between the three hosts, you
7011 must set the global option \remote_max_parallel\ to 3. This allows Exim
7012 to run 3 separate instances of the transport at once. It will pass
7013 one-third of all the addresses to each instance. Because the host list
7014 is randomized, not round-robinned, there is no guarantee that a single
7015 message will use all three hosts, but on average it should.
7018 Q9809: Can I configure Exim so that my gateway host sends a copy of each
7019 incoming message to each of two internal hosts?
7021 A9809: The easiest way to do this is to make use of the \unseen\ router option,
7022 and set up two separate routers. You need to be able to identify
7023 incoming messages somehow. Typically this can be done by testing the
7024 domain of the recipient address, in which case the configuration should
7025 contain something like this:
7028 driver = manualroute
7029 domains = ! *.your.domain.example
7030 route_data = * host1.your.domain.example
7031 transport = remote_smtp
7035 driver = manualroute
7036 domains = ! *.your.domain.example
7037 route_data = * host2.your.domain.example
7038 transport = remote_smtp
7040 The \unseen\ setting on \%r1%\ means that after it has accepted an
7041 address, the address is also passed on to \%r2%\, and so two deliveries
7045 Q9810: How can I implement ``SMTP-after-POP'' with Exim?
7050 Q9811: I would like to ``tap off'' a proportion of real mail traffic from my
7051 live mail server to use in tests of a new server. I want to preserve the
7052 envelope contents, but to suppress any error notifications to the
7058 Q9812: How can I lookup data from a single file using both single IP addresses
7059 and IP address blocks as keys? I want to set \smtp_accept_max_per_host\
7060 by this means, and also include a default.
7062 A9812: You cannot do this in a single lookup, because you need separate lookups
7063 for individual addresses and address blocks. However, these lookups can
7064 be nested in a single expansion string. For example, suppose you are
7065 using an lsearch file with entries like this:
7067 ==> 192.168.34.35: 4
7071 You can use this setting:
7073 ==> smtp_accept_max_per_host = \
7074 ${lookup{$sender_host_address}lsearch{/path/to/file}\
7077 ${lookup{${mask:$sender_host_address/24}}lsearch*{/path/to/file}}\
7080 Note that the first lookup does not have an asterisk on the search
7081 type. If you have blocks of different sizes (/24, /26, etc) you have to
7082 configure it to do a separate lookup for each size, with just the final
7083 one using a default.
7087 99. LIST OF SAMPLE CONFIGURATIONS
7089 As well as being hyperlinked from the HTML version of this document, each
7090 sample configuration is also available as a file in the \(config.samples)\
7091 directory, which can be independently downloaded.
7093 Samples whose names are of the form Cnnn are Exim configurations; those with
7094 names of the form Fnnn are filter file fragments; those with names of the form
7095 Lnnn are sample \^^local_scan()^^\ functions, and those with names of thf form
7096 Snnn are scripts of various kinds. There are other examples of
7097 \^^local_scan()^^\ functions at a number of web sites (for example,
7098 \?http://marc.merlins.org/linux/exim/sa.html?\).
7100 There are gaps in the C and F numbers because I have omitted the Exim 3 samples
7101 that have not been converted for Exim 4.
7103 C002: ``Although exim not intended for use in UUCP environment (it doesn't
7104 know anything about bang!path addresses), I'm successfully using it for
7105 delivering mail to UUCP clients.''
7107 C006: ``This is how I have configured a PP-inspired vacationnote, there is
7108 (was?) such a feature in PP. The user makes a file \(tripnote)\ in his/her
7109 home directory, the message is passed to the sender once with a short
7112 C022: ``This is the Exim configuration file of a machine which delivers mail to
7113 several local domains where the mail is delivered locally, several hairy
7114 domains, handled as described below, and a half-virtual domain, which is
7115 first processed by its special alias file, then processed as other local
7116 domains (including the processing by the global alias file).''
7118 C037: An elegant way of using ETRN, which does immediate delivery if the host
7119 is online, but saves mail in a BSMTP file after some time on the queue.
7120 ETRN then re-injects the mail.
7122 C042: ``Since the Exim 4 configuration needed to get Mailman to work differs a
7123 little bit from Exim 3 and since I still haven't seen a recipe for
7124 Mailman with Exim 4, I'm providing my configuration (based heavily on
7125 \?http://www.exim.org/howto/mailman.html?\).''
7127 C043: ``Attached is an Exim 4 config file which is designed for an Exim server
7128 that is put in front of an Exchange 5.5 system but which verifies the
7129 valid addresses that are stored in Exchange via LDAP lookups against the
7132 C044: ``I thought I'd submit this as an example of an authenticated mail hub
7133 configuration. Several people have asked for it so I thought it
7134 might be of interest.''
7136 C045: ``Here it is, for Exim 4.10 and Cyrus IMAPD 2.1.5 using db3/db4-format
7137 mailbox database. This configuration delivers the messages to Cyrus
7138 IMAPD using LMTP over a TCP/IP socket.''
7140 C046: ``Deliver a duplicate of some proportion of all messages to a special
7141 machine specified in the file \(/MAIL_TAP_HOST)\, if it exists.''
7143 C047: A sample configuration for calling Spamassassin directly from Exim.
7145 C049: ``I've been seeing a whole bunch of IPs that send me spam or virus mail
7146 and HELOing as one of my own IPs, or as HELO one.of.my.own.domains (or
7147 maybe HELO \primary_hostname\).''
7149 C050: A configuration that uses the DNS to implement virtual domains.
7151 C051: ``I've been working quite hard to come up with a config that reasonably
7152 matches the qmail-ldap setup, without the warts.''
7154 F001: ``I thought that the rest of the list may be interested in reviewing our
7155 filter as a starting point for their own system message filter.''
7157 F002: ``... program which refused mail from unknown addresses until they mailed
7158 me promising not to spam me ... since I'd already thought through how
7159 to do it in Exim, and knew it'd be slightly easier than falling out of
7160 bed, I went ahead and did it.''
7162 F003: ``Here's four checks installed in our system wide filter that knock out
7163 a lot of otherwise hard to detect rubbish.''
7165 F004: ``This is an Exim filter snippet to change locally-generated ::Message-Id::
7166 and ::Resent-Message-Id:: headers to world-unique values.''
7168 L001: A \^^local_scan()^^\ function for Exim that calls \^uvscan^\.
7170 S001: A Perl script for patching the name of the configuration file in an
7173 S002: ``When I moved from smail to exim I built a program that took individual
7174 config pieces, stripped all the comments, and built a config file.''
7176 *** End of Exim FAQ ***
git://git.exim.org / users / heiko / exim.git / blob