1 ## $Cambridge: exim/doc/doc-src/FAQ.src,v 1.3 2004/10/14 09:53:12 ph10 Exp $
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42 This is the FAQ for the Exim Mail Transfer Agent. Many thanks to the many
43 people who provided the original information. This file would be amazingly
44 cluttered if I tried to list them all. Suggestions for corrections,
45 improvements, and additions are always welcome.
47 This version of the FAQ applies to Exim 4.43 and later releases.
49 References of the form Cnnn, Fnnn, Lnnn, and Snnn are to the sample
50 configuration, filter, \^^local_scan()^^\, and ``useful script'' files. These
51 are hyperlinked from the HTML version of this FAQ. They can also be found in
52 the separately distributed directory called \(config.samples)\. The primary
55 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4/config.samples.tar.gz?\
56 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4/config.samples.tar.bz2?\
58 There are brief descriptions of these files at the end of this document.
61 Last update: 14-October-2004
64 The FAQ is divided into the following sections:
67 1. Building and Installing
69 3. Routing to remote hosts
70 4. Routing for local delivery
74 8. Rewriting addresses
82 16. Modifying message bodies
83 17. Encryption (TLS/SSL)
93 98. Configuration cookbook
94 99. List of sample configurations
100 Q0001: Exim is crashing. What is wrong?
102 A0001: Exim should never crash. The author is always keen to know about
103 crashes, so that they can be diagnosed and fixed. However, before you
104 start sending me email, please check that you are running the latest
105 release of Exim, in case the problem has already been fixed. The
106 techniques described below can also be useful in trying to pin down
107 exactly which circumstances caused the crash and what Exim was trying to
108 do at the time. If the crash is reproducible (by a particular message,
109 say) keep a copy of that message.
112 Q0002: Exim is not working. What is wrong? How can I check what it is doing?
114 A0002: Exactly how is it not working? Check the more specific questions in the
115 other sections of this FAQ. Some general techniques for debugging are:
117 (1) Look for information in Exim's log files. These are in the \(log)\
118 directory in Exim's spool directory, unless you have configured a
119 different path for them. Serious operational problems are reported
122 (2) If the problem involves the delivery of one or more messages, try
123 forcing a delivery with the \-M-\ option and also set the \-d-\
124 option, to cause Exim to output debugging information. For example:
126 ==> exim -d -M 0z6CXU-0005RR-00
128 The output is written to the standard error stream. You need to have
129 admin privileges to use \-M-\ and \-d-\.
131 (3) If the problem involves incoming SMTP mail, try using the \-bh-\
132 option to simulate an incoming connection from a specific host,
135 ==> exim -bh 10.9.8.7
137 This goes through the motions of an SMTP session, without actually
138 accepting a message. Information about various policy checks is
139 output. You will need to know how to pretend to be an SMTP client.
141 (4) If the problem involves lack of recognition or incorrect handling
142 of local addresses, try using the \-bt-\ option with debugging turned
143 on, to see how Exim is handling the address. For example,
145 ==> exim -d -bt z6abc
147 shows you how it would handle the local part \"z6abc"\.
150 Q0003: What does the error \*Child process of address_pipe transport returned
151 127 from command xxx*\ mean?
153 A0003: It means that when a transport called \%address_pipe%\ was run to pass an
154 email message by means of a pipe to another process running the command
155 xxx, the return code from that command was 127, which indicates some kind
156 of error (the success return code is 0).
158 The most common meaning of exit code 127 is that when Exim tried to run
159 the command \(xxx)\, it failed. One cause of this might be incorrect
160 permissions on the file containing the command. See also Q0026.
163 Q0004: My virtual domain setup isn't working. How can I debug it?
165 A0004: You can use an exim command with \-d-\ to get it to show you how it is
166 processing addresses. You don't actually need to send a message; use the
167 \-bt-\ option like this:
169 ==> exim -d -bt localpart@virtualhost
171 This will show you which routers it is using. If the problem appears
172 to be with the expansion of an option setting, you can use the
173 \debug_print\ option on a router to get Exim to output the expanded
174 string values as it goes along.
177 Q0005: Why is Exim not rejecting incoming messages addressed to non-existent
180 A0005: This is controlled by the ACL that is run for each incoming RCPT
181 command. It is defined by the \acl_smtp_rcpt\ option. You can check this
182 part of your configuration by using the \-bh-\ option to run a simulated
183 SMTP session, during which Exim will tell you what things it is
187 Q0006: I've put an entry for \"*.my.domain"\ in a DBM lookup file, but it isn't
190 A0006: You need to request ``partial matching'' by setting the search type to
191 \partial-dbm\ in order for this to work.
194 Q0007: I've put the entry \"*@domain.com"\ in a lookup database, but it isn't
195 working. The expansion I'm using is:
197 ==> ${lookup{${lc:$sender_address}}dbm{/the/file} ...
199 A0007: As no sender address will ever be //*@domain.com// this will indeed have
200 no effect as it stands. You need to tell Exim that you want it to look
201 for defaults after the normal lookup has failed. In this case, change the
202 search type from \"dbm"\ to \"dbm*@"\. See the section on \*Default values in
203 single-key lookups*\ in the chapter entitled \*File and database
204 lookups*\ in the Exim manual.
207 Q0008: If I run \"./exim -d -bt user@domain"\ all seems well, but when I send
208 a message from my User Agent, it does not arrive at its destination.
210 A0008: Try sending a message directly to Exim by typing this:
212 ==> exim -v user@domain
213 <some message, could be empty>
216 If the message gets delivered to a remote host, but never arrives at its
217 final destination, then the problem is at the remote host. If, however,
218 the message gets through correctly, then the problem may be between your
219 User Agent and Exim. Try setting Exim's \log_selector\ option to include
220 \"+arguments"\, to see with which arguments the UA is calling Exim.
223 Q0009: What does \*no immediate delivery: too many messages received in one SMTP
226 A0009: An SMTP client may send any number of messages down a single SMTP
227 connection to a server. Initially, an Exim server starts up a delivery
228 process as soon as a message is received. However, in order not to start
229 up too many processes when lots of messages are arriving (typically
230 after a period of downtime), it stops doing immediate delivery after a
231 certain number of messages have arrived down the same connection. The
232 threshold is set by \smtp_accept_queue_per_connection\, and the default
233 value is 10. On large systems, the value should be increased. If you are
234 running a dial-in host and expecting to get all your mail down a single
235 SMTP connection, then you can disable the limit altogether by setting
239 Q0010: Exim puts \*for \[address]\*\ in the ::Received:: headers of some, but not all,
240 messages. Is this a bug?
242 A0010: No. It is deliberate. Exim inserts a ``for'' phrase only if the incoming
243 message has precisely one recipient. If there is more than one
244 recipient, nothing is inserted. The reason for this is that not all
245 recipients appear in the ::To:: or ::Cc:: headers, and it is considered a
246 breach of privacy to expose such recipients to the others. A common
247 case is when a message has come from a mailing list.
250 Q0011: Instead of \^exim_dbmbuild^\, I'm using a homegrown program to build DBM
251 (or cdb) files, but Exim doesn't seem to be able to use them.
253 A0011: Exim expects there to be a binary zero value on the end of each key used
254 in a DBM file if you use the \"dbm"\ lookup type, but not for the \"dbmnz"\
255 lookup type or for the keys of a cdb file. Check that you haven't
256 slipped up in this regard.
259 Q0012: Exim is unable to route to any remote domains. It doesn't seen to be
260 able to access the DNS.
262 A0012: Try running \"exim -d+resolver -bt \[remote address]\"\. The \-d-\
263 options turns on debugging output, and the addition of \"+resolver"\
264 will make it show the resolver queries it is building and the results of
265 its DNS queries. If it appears unable to contact any name servers, check
266 the contents and permissions of \(/etc/resolv.conf)\.
269 Q0013: What does the error message \*transport system_aliases: cannot find
270 transport driver "redirect" in line 92*\ mean?
272 A0013: \%redirect%\ is a router, not a transport. You have put a configuration
273 for a router into the transports section of the configuration file.
276 Q0014: Exim is timing out after receiving and responding to the DATA command
277 from one particular host, and yet the client host also claims to be
278 timing out. This seems to affect only certain messages.
280 A0014: This kind of problem can have many different causes.
282 (1) This problem has been seen with a network that was dropping all
283 packets over a certain size, which mean that the first part of the SMTP
284 transaction worked, but when the body of a large message started
285 flowing, the main data bits never got through the network. See also
288 (2) This can also happen if a host has a broken TCP stack and won't
289 reassemble fragmented datagrams.
291 (3) A very few ISDN lines have been seen which failed when certain data
292 patterns were sent through them, and replacing the routers at both end
293 of the link did not fix things. One of them was triggered by more than 4
294 X's in a row in the data.
297 Q0015: What does the message \*Socket bind() to port 25 for address (any)
298 failed: address already in use*\ mean?
300 A0015: You are trying to run an Exim daemon when there is one already running -
301 or maybe some other MTA is running, or perhaps you have an SMTP line in
302 \(/etc/inetd.conf)\ which is causing \(inetd)\ to listen on port 25.
305 Q0016: I've set \"verify = header_syntax"\ in my ACL, but this causes Exim to
306 complain about header lines like \"To: Work: Jim <jims@email>,
307 Home: Bob <bobs@email>"\ which look all right to me. Is this a bug?
309 A0016: No. Header lines such as ::From::, ::To::, etc., which contain addresses, are
310 structured, and have to be in a specific format which is defined in RFC
311 2822. Unquoted colons are not allowed in the ``phrase'' part of an email
312 address (they are OK in other headers such as ::Subject::). The correct
313 form for that header is
315 ==> To: "Work: Jim" <jims@email>, "Home: Bob" <bobs@email>
317 You will sometimes see unquoted colons in ::To:: and ::Cc:: headers, but only
318 in connection with name lists (called ``groups''), for example:
320 ==> To: My friends: X <x@y.x>, Y <y@w.z>;,
321 My enemies: A <a@b.c>, B <b@c.d>;
323 Each list must be terminated by a semicolon, as shown.
326 Q0017: Whenever Exim tries to deliver a specific message to a particular
327 server, it fails, giving the error \*Remote end closed connection after
328 data*\ or \*Broken pipe*\ or a timeout. What's going on?
330 A0017: \*Broken pipe*\ is the error you get on some OS when the remote host just
331 drops the connection. The alternative is \*connection reset by peer*\.
332 There are many potential causes. Here are some of them (see also Q0068):
334 (1) There are some firewalls that fall over on binary zero characters
335 in email. Have a look, e.g. with \"hexdump -c mymail | tail"\ to see if
336 your mail contains any binary zero characters.
338 (2) There are broken SMTP servers around that just drop the connection
339 after the data has been sent if they don't like the message for some
340 reason (e.g. it is too big) instead of sending a 5xx error code. Have
341 you tried sending a small message to the same address?
343 It has been reported that some releases of Novell servers running NIMS
344 are unable to handle lines longer than 1024 characters, and just close
345 the connection. This is an example of this behaviour.
347 (3) If the problem occurs right at the start of the mail, then it could
348 be a network problem with mishandling of large packets. Many emails are
349 small and thus appear to propagate correctly, but big emails will
350 generate big IP datagrams.
352 There have been problems when something in the middle of the network
353 mishandles large packets due to IP tunnelling. In a tunnelled link, your
354 IP datagrams gets wrapped in a larger datagram and sent over a network.
355 This is how virtual private networks (VPNs), and some ISP transit
356 circuits work. Since the datagrams going over the tunnel require a
357 larger packet size, the tunnel needs a bigger maximum transfer unit
358 (MTU) in the network handling the tunnelled packets. However, MTUs
359 are often fixed, so the tunnel will try to fragment the packets.
361 If the systems outside the tunnel are using path MTU discovery, (most
362 Sun Sparc Solaris machines do by default), and set the DF (don't
363 fragment) bit because they don't send packets larger than their \(local)\
364 MTU, then ICMP control messages will be sent by the routers at the
365 ends of the tunnel to tell them to reduce their MTU, since the tunnel
366 can't fragment the data, and has to throw it away. If this mechanism
367 stops working, e.g. a firewall blocks ICMP, then your host never
368 knows it has hit the maximum path MTU, but it has received no ACK on
369 the packet either, so it continues to resend the same packet and the
370 connection stalls, eventually timing out.
372 You can test the link using pings of large packets and see what works:
374 ==> ping -s host 2048
376 Try reducing the MTU on the sending host:
378 ==> ifconfig le0 mtu 1300
380 Alternatively, you can reduce the size of the buffer Exim uses for SMTP
381 output by putting something like
383 ==> DELIVER_OUT_BUFFER_SIZE=512
385 in your \(Local/Makefile)\ and rebuilding Exim (the default is 8192).
386 While this should not in principle have any effect on the size of
387 packets sent, in practice it does seem to have an effect on some OS.
389 You can also try disabling path MTU discovery on the sending host. On
392 ==> echo 1 >/proc/sys/net/ipv4/ip_no_pmtu_disc
394 For a general discussion and information about other operating systems, see
395 \?http://www.netheaven.com/pmtu.html?\. If disabling path MTU discovery
396 fixes the problem, try to find the broken or misconfigured
397 router/firewall that swallows the ICMP-unreachable packets. Increasing
398 timeouts on the receiving host will not work around the problem.
401 Q0018: Why do messages not get delivered down the same connection when I do
402 something like: \"exim -v -R @aol.com"\? For other domains, I do this and
403 I see the appropriate \*waiting for passed connections to get used*\
406 A0018: Recall that Exim does not keep separate queues for each domain, but
407 operates in a distributed fashion. Messages get into its `waiting for
408 host x' hints database only when a delivery has been tried, and has had
409 a temporary error. Here are some possibilities:
411 (1) The messages to \(aol.com)\ got put in your queue, but no previous
412 delivery attempt occured before you did the \-R-\. This might have been
413 because of your settings of \queue_only_load\, \smtp_accept_queue\, or any
414 other option that caused no immediate delivery attempt on arrival. If
415 this is the case, you can try using \-qqR-\ instead of \-R-\.
417 (2) You have set \connection_max_messages\ on the smtp transport, and
418 that limit was reached. This would show as a sequence of messages
419 down one connection, then another sequence down a new connection, etc.
421 (3) Exim tried to pass on the SMTP connection to another message, but
422 that message was in the process of being delivered to \(aol.com)\ by some
423 other process (typically, a normal queue runner). This will break the
424 sequence, though the other delivery should pass its connection on to
425 other messages if there are any.
427 (4) The folk at \(aol.com)\ changed the MX records so the host names have
428 changed - or a new host has been added. I don't know how likely this is.
430 (5) Exim is not performing as it should in this regard, for some reason.
431 Next time you have mail queued up for \(aol.com)\, try running
433 ==> exim_dumpdb /var/spool/exim wait-remote_smtp
435 to see if those messages are listed among those waiting for the relevant
439 Q0019: There seems to be a problem in the string expansion code: it doesn't
440 recognize references to headers such as \"${h_to}"\.
442 A0019: The only valid syntax for header references is (for example) \"$h_to:"\
443 because header names are permitted by RFC 2822 to contain a very wide
444 range of characters. A colon (or white space) is required as the
448 Q0020: Why do connections to my machine's SMTP port take a long time to respond
449 with the banner, when connections to other ports respond instantly? The
450 delay is sometimes as long as 30 seconds.
452 A0020: These kinds of delay are usually caused by some kind of network problem
453 that affects outgoing calls made by Exim at the start of an incoming
454 connection. Configuration options that cause outgoing calls are:
456 (1) \rfc1413_hosts\ and \rfc1413_query_timeout\ (for \*ident*\ calls).
457 Firewalls sometimes block ident connections so that they time out,
458 instead of refusing them immediately. This can cause this problem.
459 See Q5023 for a discussion of the usefulness of \*ident*\.
461 (2) The \host_lookup\ option, the \host_reject_connection\ option, or a
462 condition in the ACL that runs at connection time requires the
463 remote host's name to be looked up from its IP address. Sometimes
464 these DNS lookups time out. You can get this effect with ACL
465 statements like this:
467 ==> deny hosts = *.x.example
469 If at all possible, you should use IP addresses instead of host
470 names in blocking lists in order to to avoid this problem.
472 You can use the \-bh-\ option to get more information about what is
473 happening at the start of a connection. However, note that the \-bh-\
474 option does not provide a complete simulation. In particular, no
475 \*ident*\ checks are done, so it won't show up a delay problem that is
476 related to (1) above.
479 Q0021: What does \*failed to create child process to send failure message*\ mean?
480 This is a busy mail server with \smtp_accept_max\ set to 500, but this
481 problem started to occur at about 300 incoming connections.
483 A0021: Some message delivery failed, and when Exim wanted to send a bounce
484 message, it was unable to create a process in which to do so. Probably
485 the limit on the maximum number of simultaneously active processes has
486 been reached. Most OS have some means of increasing this limit, and in
487 some operating systems there is also a limit per uid which can be
491 Q0022: What does \*No transport set by system filter*\ in a log line mean?
493 A0022: Your system filter contains a \"pipe"\ or \"save"\ or \"mail"\ command,
494 but you have not set the corresponding option which specifies which
495 transport is to be used. You need to set whichever of
496 \system_filter_pipe_transport\, \system_filter_file_transport\ or
497 \system_filter_reply_transport\ is relevant.
500 Q0023: Why is Exim refusing to relay, saying \*failed to find host name from IP
501 address*\ when I have the sender's IP address in an ACL condition? My
502 configuration contains this ACL statement:
504 ==> accept hosts = lsearch;/etc/mail/relaydomains:192.168.96.0/24
506 A0023: When checking a host list, the items are tested in left-to-right
507 order. The first item in your list is a lookup on the incoming host's
508 name, so Exim has to determine the name from the incoming IP address in
509 order to perform the test. If it can't find the host name, it can't do
510 the check, so it gives up. You would have discovered what was going
511 on if you had run a test such as
513 ==> exim -bh 192.168.96.131
515 The solution is to put all explicit IP addresses first in the list.
516 Alternatively, you can split the ACL statement into two like this:
518 ==> accept hosts = lsearch;/etc/mail/relaydomains
519 accept hosts = 192.168.96.0/24
521 If the host lookup fails, the first \"accept"\ fails, but then the
522 second one is considered.
525 Q0024: When I run \"exim -bd -q10m"\ I get \*PANIC LOG: exec of exim -q failed*\.
527 A0024: This probably means that Exim doesn't know its own path so it can't
528 re-exec itself to do the first queue run. Check the output of
530 ==> exim -bP exim_path
533 Q0025: I can't seem to get a pipe command to run when I include a \"${if"\
534 expansion in it. This fails:
536 ==> command = perl -T /usr/local/rt/bin/rtmux.pl \
537 rt-mailgate helpdesk \
538 ${if eq {$local_part}{rt} {correspond}{action}}
540 A0025: You need some internal quoting in there. Exim expands each individual
541 argument separately. Because you have (necessarily) got spaces in your
542 \"${if"\ item, you have to quote that argument. Try
544 ==> command = perl -T /usr/local/rt/bin/rtmux.pl \
545 rt-mailgate helpdesk \
546 "${if eq {$local_part}{rt} {correspond}{action}}"
548 \**Warning:**\ If command starts with an item that requires quoting,
549 you cannot just put it in quotes, because a leading quote means that the
550 entire option setting is being quoted. What you have to do is to quote
551 the entire value, and use internally escaped quotes for the ones you
552 really want. For example:
554 ==> command = "\"${if ....}\" arg1 arg2"
556 Any backslashes in the expansion items will have to be doubled to stop
557 them being interpreted by the string reader.
560 Q0026: I'm trying to get Exim to connect an alias to a pipe, but it always
561 gives error code 127, with the comment \*(could mean unable to exec
562 or command does not exist)*\.
564 A0026: If your alias entry looks like this:
566 ==> alias: |"/some/command some parameters"
568 change it to look like this:
570 ==> alias: "|/some/command some parameters"
573 Q0027: What does the error \*Spool file is locked*\ mean?
575 A0027: This is not an error. All it means is that when an Exim delivery
576 process (probably started by a queue runner process) looked at a message
577 in order to start delivering it, it found that another Exim process was
578 already busy delivering it. On a busy system this is quite a common
579 occurrence. If you set \"-skip_delivery"\ in the \log_selector\ option,
580 these messages are omitted from the log.
582 The only time when this message might indicate a problem is if it is
583 repeated for the same message for a very long time. That would suggest
584 that the process that is delivering the message has somehow got stuck.
587 Q0028: Exim is reporting IP addresses as 0.0.0.0 or 255.255.255.255 instead of
588 their correct values. What's going on?
590 A0028: You are using a version of Exim built with gcc on an IRIX box.
594 Q0029: I can't seem to figure out why PAM support doesn't work correctly.
596 A0029: There is a problem using PAM with shadow passwords when the calling
597 program is not running as \/root/\. Exim is normally running as the
598 Exim user when authenticating a remote host.
600 (1) One solution can be found at \?http://www.e-admin.de/pam_exim/?\.
602 (2) PAM 0.72 allows authorization as non-\/root/\, using setuid helper
603 programs. Furthermore, in \(/etc/pam.d/exim)\ you can explicitly
604 specify that this authorization (using setuid helpers) is only
605 permitted for certain users and groups.
607 (3) Another approach is to authenticate using the \^saslauthd^\ daemon,
608 which has its own interface to PAM. The daemon runs as root, so
609 there is no access problem.
611 (4) One suggested solution was to set
613 ==> exim_group=shadow
615 in the configuration file, or the equivalent at build time. This is
616 very strongly discouraged. Do not do it! It works, but it's a
617 potential security exposure. Exim is intended to run as a
618 non-privileged user for much of the time. This setting gives it have
619 privileged access to crucial security information all of the time,
620 simply for the purposes of authentication (which Exim will only
621 spend a tiny part of its total time doing). The result is that a
622 successful compromise of the Exim system can give someone direct
623 access to the system passwords.
626 Q0030: I'm trying to use a query-style lookup for hosts that are allowed to
627 relay, but it is giving really weird errors.
629 A0030: Does your query contain a colon character? Remember that host lists are
630 colon-separated, so you need to double any colons in the query. This
631 applies even if the query is defined as a macro.
634 Q0031: Exim is rejecting connections from hosts that have more than one IP
635 address, for no apparent reason.
637 A0031: You are using Solaris 7 or earlier, and have \"nis dns files"\ in
638 \(/etc/nsswitch.conf)\. Change this to \"dns nis files"\ to avoid hitting Sun
639 bug 1154236 (a bad interaction between NIS and the DNS).
642 Q0032: Exim is failing to find the MySQL library, even though is it present
643 within \\LD_LIBRARY_PATH\\. I'm getting this error:
645 ==> /usr/local/bin/exim: fatal: libmysqlclient.so.6: open failed:
646 No such file or directory
648 A0032: Exim is suid, and \\LD_LIBRARY_PATH\\ is ignored for suid binaries on a
649 Solaris (and other?) systems. What you should be doing is adding
650 \"-R/local/lib/mysql"\ to the same place in the compilation that you added
651 \"-L/local/lib/mysql"\. This tells the binary where to look without
652 needing a path variable.
655 Q0033: What does the error \*lookup of host "xx.xx.xx" failed in yyy router*\
658 A0033: You configured a \%manualroute%\ router to send the message to xx.xx.xx. When
659 it tried to look up the IP address for that host, the lookup failed
660 with a permanent error. As this is a manual routing, this is a
661 considered to be a serious error which the postmaster needs to know
662 about (maybe you have a typo in your file), and there is little point
663 in keeping on trying. So it freezes the message.
665 (1) Don't set up routes to non-existent hosts.
667 (2) If you must set up routes to non-existent hosts, and don't want
668 freezing, set the \host_find_failed\ option on the router to do something
672 Q0034: Exim works fine on one host, but when I copied the binary to another
673 identical host, it stopped working (it could not resolve DNS names).
675 A0034: Is the new host running exactly the same operating system? Most
676 importantly, are the versions of the dynamically loaded libraries
677 (files with names like \(libsocket.so.1)\) the same on both systems? If not,
678 that is probably the cause of the problem. Either arrange for the
679 libraries to be the same, or rebuild Exim from source on the new host.
682 Q0035: I set a \"hosts"\ condition in an ACL to do a lookup in a file of IP
683 addresses, but it doesn't work.
685 A0035: Did you remember to put \"net-"\ at the start of the the search type? If
686 you set something like this:
688 ==> accept hosts = lsearch;/some/file
690 Exim searches the file for the host name, not the IP address. You need
693 ==> accept hosts = net-lsearch;/some/file
695 to make it use the IP address as the key to the lookup.
698 Q0036: Why do I get the error \*Permission denied: creating lock file hitching
699 post*\ when Exim tries to do a local delivery?
701 A0036: Your configuration specifies that local mailboxes are all held in
702 single directory, via configuration lines like these (taken from the
703 default configuration):
707 file = /var/mail/$local_part
709 and the permissions on the directory probably look like this:
711 ==> drwxrwxr-x 3 root mail 512 Jul 9 13:48 /var/mail/
713 Using the default configuration, Exim runs as the local user when doing
714 a local delivery, and it uses a lock file to prevent any other process
715 from updating the mailbox while it is writing to it. With those
716 permissions the delivery process, running as the user, is unable to
717 create a lock file in the \(/var/mail(\ directory. There are two solutions
720 (1) Set the \"write"\ and \"sticky bit"\ permissions on the directory, so
721 that it looks like this:
723 ==> drwxrwxrwt 3 root mail 512 Jul 9 13:48 /var/mail/
725 The \"w"\ allows any user to create new files in the directory, but
726 the \"t"\ bit means that only the creator of a file is able to remove
727 it. This is the same setting as is normally used with the \(/tmp)\
730 (2) Arrange to run the local_delivery transport under a specific group
731 by changing the configuration to read
735 file = /var/mail/${local_part}
738 The delivery process still runs under the user's uid, but with the
739 group set to \"mail"\. The group permission on the directory allows
740 the process to create and remove the lock file.
742 The choice between (1) and (2) is up to the administrator. If the
743 second solution is used, users can empty their mailboxes by updating
744 them, but cannot delete them.
746 If your problem involves mail to \/root/\, see also Q0507.
749 Q0037: I am experiencing mailbox locking problems with Sun's \"mailtool"\ used
752 A0037: See Q9705 in the Sun-specific section below.
755 Q0038: What does the error message \*error in forward file (filtering not
756 enabled): missing or malformed local part*\ mean?
758 A0038: If you are trying to use an Exim filter, you have forgotten to enable
759 the facility, which is disabled by default. In the \%redirect%\ router
760 (in the Exim run time configuration file) you need to set
762 ==> allow_filter = true
764 to allow a \(.forward)\ file to be used as an Exim filter. If you are not
765 trying to use an Exim filter, then you have put a malformed address in
766 the \(.forward)\ file.
769 Q0039: I have installed Exim, but now I can't mail to \/root/\ any more. Why is
772 A0039: Most people set up \/root/\ as an alias for the manager of the host. If
773 you haven't done this, Exim will attempt to deliver to \/root/\ as if it
774 were a normal user. This isn't really a good idea because the delivery
775 process would run as \/root/\. Exim has two trigger guards that stop
776 deliveries running as root. In the build-time configuration, there is a
777 setting called FIXED_NEVER_USERS, which defaults to \"root"\. This
778 setting cannot be overridden. In addition, the default runtime
779 configuration contains the option
781 ==> never_users = root
783 just to be on the safe side. If you really want to run local deliveries
784 as \/root/\, you must use a version of Exim that was built without the
785 FIXED_NEVER_USERS option, and remove the above line from the runtime
786 configuration, but it would be better to create an alias for \/root/\
790 Q0040: How can I stop undeliverable bounce messages (e.g. to routeable, but
791 undeliverable, spammer senders) from clogging up the queue for days?
793 A0040: If at all possible, you should try to avoid getting into this situation
794 in the first place, for example, by verifying recipients so that you
795 do not accept undeliverable messages that lead to these bounces.
796 You can, however, configure Exim to discard failing bounce messages
797 early. Just set \ignore_bounce_errors_after\ to specify a (short) time
801 Q0041: What does the message \*unable to set gid=ddd or uid=ddd (euid=ddd):
802 local delivery to ... transport=ttt*\ mean?
804 A0041: Have you remembered to make Exim setuid \/root/\? It needs root privilege if
805 it is to do any local deliveries, because it does them ``as the user''.
806 Note also that the partition from which Exim is running (where the
807 binary is installed) must not have the \nosuid\ mount option set. You
808 can check this by looking at its \(/etc/fstab)\ entry (or \(/etc/vfstab)\,
809 depending on your OS).
812 Q0042: My ISP's mail server is rejecting bounce messages from Exim, complaining
813 that they have no sender. The SMTP trace does indeed show that the
814 sender address is \"<>"\. Why is the Sender on the bounce message empty?
816 A0042: Because the RFCs say it must be. Your ISP is at fault. Send them this
817 extract from RFC 2821 section 6.1 (\*Reliable Delivery and Replies by
820 If there is a delivery failure after acceptance of a message, the
821 receiver-SMTP MUST formulate and mail a notification message. This
822 notification MUST be sent using a null (\"<>"\) reverse path in the
823 envelope. The recipient of this notification MUST be the address
824 from the envelope return path (or the ::Return-Path:: header line).
825 However, if this address is null (\"<>"\), the receiver-SMTP MUST NOT
828 The reason that bounce messages have no sender is so that they
829 themselves cannot provoke further bounces, as this could lead to a
830 unending exchange of undeliverable messages.
833 Q0043: What does the error \*Unable to get interface configuration: 22 Invalid
836 A0043: This is an error that occurs when Exim is trying to find out the all the
837 IP addresses on all of the local host's interfaces. If you have lots of
838 virtual interfaces, this can occur if there are more than around 250 of
839 them. The solution is to set the option \local_interfaces\ to list just
840 those IP addresses that you want to use for making and receiving SMTP
844 Q0044: What does the error \*Failed to create spool file*\ mean?
846 A0044: Exim has been unable to create a file in its spool area in which to
847 store an incoming message. This is most likely to be either a
848 permissions problem in the file hierarchy, or a problem with the uid
849 under which Exim is running, though it could be something more drastic
850 such as your disk being full.
852 If you are running Exim with an alternate configuration file using a
853 command such as \"exim -C altconfig..."\, remember that the use of -C
854 takes away Exim's root privilege.
856 Check that you have defined the spool directory correctly by running
858 ==> exim -bP spool_directory
860 and examining the output. Check the mode of this directory. It should
861 look like this, assuming you are running Exim as user \/exim/\:
863 ==> drwxr-x--- 6 exim exim 512 Jul 16 12:29 /var/spool/exim
865 If there are any subdirectories already in existence, they should have
866 the same permissions, owner, and group. Check also that you haven't got
867 incorrect permissions on superior directories (for example, \(/var/spool)\).
868 Check that you have set up the Exim binary to be setuid \/root/\. It should
871 ==> -rwsr-xr-x 1 root xxx 502780 Jul 16 14:16 exim
873 Note that it is not just the owner that must be \/root/\, but also the third
874 permission must be \"s"\ rather than \"x"\.
877 Q0045: I see entries in the log that mention two different IP addresses for the
878 same connection. Why is this? For example:
880 ==> H=tip-mp8-ncs-13.stanford.edu ([36.173.0.189]) [36.173.0.156]
882 A0045: The actual IP address from which the call came is the final one.
883 Whenever there's something in parentheses in a host name, it is what the
884 host quoted as the domain part of an SMTP HELO or EHLO command. So in
885 this case, the client, despite being 36.173.0.156, issued the command
887 ==> EHLO [36.173.0.189]
889 when it sent your server the message. This is, of course, very
893 Q0046: A short time after I start Exim I see a defunct zombie process. What
896 A0046: Your system must be lightly loaded as far as mail is concerned. The
897 daemon sets off a queue runner process when it is started, but it only
898 tidies up completed child processes when it wakes up for some other
899 reason. When there's nothing much going on, you occasionally see
900 defunct processes like this waiting to be dealt with. This is
904 Q0047: On a reboot, or a restart of the mail system, I see the message \*Mailer
905 daemons: exim abandoned: unknown, malformed, or incomplete option
906 -bz sendmail*\. What does this mean?
908 A0047: \-bz-\ is a Sendmail option requesting it to create a `configuration freeze
909 file'. Exim has no such concept and so does not support the option. You
910 probably have a line like
912 ==> /usr/lib/sendmail -bz
914 in some start-up script (e.g. \(/etc/init.d/mail)\) immedately before
916 ==> /usr/lib/sendmail -bd -q15m
918 The first of these lines should be commented out.
921 Q0048: Whenever exim restarts it takes up to 3-5 minutes to start responding on
922 the SMTP port. Why is this?
924 A0048: Something else is hanging onto port 25 and not releasing it. One place
925 to look is \(/etc/inetd.conf)\ in case for any reason an SMTP stream is
929 Q0049: What does the log message \*no immediate delivery: more than 10 messages
930 received in one connection*\ mean?
932 A0049: A remote MTA sent a number of messages in a single SMTP session. Exim
933 limits the number of immediate delivery processes it creates as a
934 result of a single SMTP connection, in order to avoid creating a zillion
935 processes on systems that can have many incoming connections. If you are
936 dialing in to collect mail from your ISP, you should probably set
937 \smtp_accept_queue_per_connection\ to some number larger than 10, or
938 arrange to start a queue runner for local delivery (using \-ql-\)
939 immediately after collecting the mail.
942 Q0050: I am getting complaints from a customer who uses my Exim server for
943 relaying that they are being blocked with a \*Too many connections*\
946 A0050: See \smtp_accept_max\, \smep_accept_max_per_host\ and \smtp_accept_reserve\.
949 Q0051: When I test my system filter with \-bf-\, I get the error \*filtering
950 command "fail" is disabled*\. Why is this?
952 A0051: Use the \-bF-\ option to test system filters. This gives you access to the
953 freeze and fail actions.
956 Q0052: What does \*ridiculously long message header*\ in an error report mean?
958 A0052: There has to be some limit to the length of a message's header lines,
959 because otherwise a malefactor could open an SMTP channel to your host,
960 start a message, and then just send characters continuously until your
961 host runs out of memory. (Exim stores all the header lines in main
962 memory while processing a message). For this reason a limit is imposed
963 on the total amount of memory that can be used for header lines. The
964 default is 1MB, but this can be changed by setting \\HEADER_MAXSIZE\\ in
965 \(Local/Makefile)\ before building Exim. Exceeding the limit provokes
966 the ``ridiculous'' error message.
969 Q0053: Exim on my host responds to a connection with \"220 *****..."\ and
970 won't understand \\EHLO\\ commands.
972 A0053: This is the sign of a Cisco Pix ``Mailguard'' sitting in front of your
973 MTA. Pix breaks ESMTP and only does SMTP. It is a nuisance when you have
974 a secure MTA running on your box. Something like ``no fixup protocol
975 smtp 25'' in the Pix configuration is needed. It may be possible to do
976 this by logging into the Pix (using \^telnet^\ or \^ssh^\) and typing
977 \"no fixup smtp"\ to its console. (You may need to use other commands
978 before or after to set up configuration mode and to activate a changed
979 configuration. Consult your Pix documentation or expert.) See also
983 Q0054: I'm getting an Exim configuration error \*unknown rewrite flag
984 character (m) in line 386*\ but I haven't used any flags on my rewriting
987 A0054: You have probably forgotten to quote a replacement string that contains
991 Q0055: What does the error \*Failed to open wait-remote_smtp database: Invalid
994 A0055: This is something that happens if you have existing DBM hints files when
995 you install a new version of Exim that is compiled to use a different or
996 upgraded DBM library. The simplest thing to try is
998 ==> rm /var/spool/exim/db/*
1000 This removes all the hints files. Exim will start afresh and build new
1001 ones. If the symptom recurs, it suggests there is some problem with your
1005 Q0056: We are using Exim to send mail from our web server. However, whenever a
1006 user sends an email it gets sent with the return path (envelope sender)
1007 //apache@server_name.com// because the PHP script is running as
1010 A0056: You need to include \/apache/\ in the \trusted_users\ configuration option.
1011 Only trusted users are permitted to specify senders when mail is passed
1012 to Exim via the command line.
1015 Q0057: We've got people complaining about attachments that don't show up
1016 as attachments, but are included in the body of the message.
1018 A0057: In the past, these symptoms could be seen when some software passed a
1019 CRLF line terminated message via the command line, because Exim expected
1020 lines to be terminated by LF only, and so it preserved the CRs as data.
1021 Modern versions of Exim (4.21 or later) use heuristics to try to do the
1022 right thing with line endings.
1025 Q0058: What does the error \*failed to open DB file \(/var/spool/exim/db/retry)\:
1028 A0058: This error is most often caused when a hints file that was written with
1029 one version of the Berkeley DB library is read by another version.
1030 Sometimes this can happen if you change from a binary version of Exim to
1031 a locally compiled version. Or it can happen if you compile and install
1032 a new version of Exim after changing Berkeley DB versions. You can find
1033 out which version your Exim is using by running:
1035 ==> ldd /usr/sbin/exim
1037 The solution to the problem is to delete all the files in the
1038 \(/var/spool/exim/db)\ directory, and let Exim recreate them.
1041 Q0059: When my Outlook Express 6.0 client sends a STARTTLS command to begin a
1042 TLS session, Exim doesn't seem to receive it. The Outlook log shows
1045 ==> SMTP: 14:19:27 [tx] STARTTLS
1046 SMTP: 14:19:27 [rx] 500 Unsupported command.
1048 but the Exim debugging output shows this:
1050 ==> SMTP<< EHLO xxxx
1051 SMTP>> 250-yyyy Hello xxxx [nnn.nnn.nnn.nnn]
1054 250-AUTH CRAM-MD5 PLAIN LOGIN
1059 A0059: Turn off scanning of outgoing email in Norton Antivirus. If you aren't
1060 running Norton Antivirus, see if you are running some other kind of SMTP
1061 proxying, either on the client or on a firewall between the client and
1062 server. ``Unsupported command'' is not an Exim message.
1065 Q0060: Why am I getting the error \*failed to expand \"/data/lists/lists/${lc"\
1066 for require_files: \"${lc"\ is not a known operator*\ for this setting:
1068 ==> require_files = MAILMAN_HOME/lists/${lc:$local_part}/config.db
1070 A0060: The value of \"require_files"\ is a list in which each item is
1071 separately expanded. In other words, the splitting into items happens
1072 before the string expansion. You need either to double the colon, or
1073 switch to a different list separator.
1076 Q0061: What does the error \*Too many ``Received'' headers - suspected mail
1079 A0061: Whenever a message passes through an MTA, a ::Received:: header gets
1080 added. Exim counts the number of these headers in incoming messages. If
1081 there are more than the value of \received_headers_max\ (default 30),
1082 Exim assumes there is some kind of mail routing loop occurring. For
1083 example, host A passes the message to host B, which immediately passes
1084 it back to host A. Check the ::Received:: headers and the mail logs to
1085 determine exactly what is going on.
1087 One common cause of this problem is users with accounts on both systems
1088 who set up each one to forward to the other, thinking that will cause
1089 copies of all messages to be delivered on both of them.
1092 Q0062: When I try to start an Exim daemon with \-bd-\ it crashes. I ran a
1093 debugger and discovered that the crash is happening in the function
1094 \^^getservbyname()^^\. What's going on?
1096 A0062: What have you got in the file \(/etc/nsswitch.conf)\? If it contains this
1099 ==> services: db files
1101 try removing the \"db"\. Your system is trying to look in some kind of
1102 database before searching the file \(/etc/services)\, and there is an
1103 incompatibility the is causing the function \^^getservbyname()^^\ crash.
1104 This is an OS problem. See, for instance:
1106 \?http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=129025?\
1108 Another workaround in Exim is to set
1110 ==> daemon_smtp_port = 25
1112 in the configuration, to stop Exim calling \^^getservbyname()^^\.
1115 Q0063: When I try to start an Exim daemon, nothing happens. There is no
1116 process, and nothing is written to the Exim log.
1118 A0063: Check to see if anything is written to \(syslog)\. This problem can be
1119 caused by a permission problem that stops Exim from writing to its log
1120 files, especially if you've specified that they should be written
1121 somewhere other than under Exim's spool directory. You could also try
1122 running the daemon with debugging turned on.
1125 Q0064: When I run \"exim -d test@domain"\ it delivers fine, but when I send a
1126 message from the \^mail^\ command, I get \*User unknown*\ and the mail
1127 is saved in \(dead.letter)\.
1129 A0064: It looks as if Exim isn't being called by \^mail^\; instead it is
1130 calling some other program (probably Sendmail). Try running the command
1132 ==> /usr/sbin/sendmail -bV
1134 (If you get \*No such file or directory*\ or \*Command not found*\ you
1135 are running Solaris or IRIX. Try again with \(/usr/lib/sendmail)\.) The
1136 output should be something like this:
1138 ==> Exim version 4.05 #1 built 13-Jun-2002 10:27:15
1139 Copyright (c) University of Cambridge 2002
1141 If you don't see this, your Exim installation isn't fully operational.
1142 If you are running FreeBSD, see Q9201. For other systems, see Q0114.
1145 Q0065: When (as \/root/\) I use -C to run Exim with an alternate configuration
1146 file, it gives an error about being unable to create a spool file when
1147 trying to run an \%autoreply%\ transport. Why is this?
1149 A0065: When Exim is called with -C, it passes on -C to any instances of itself
1150 that it calls (so that the whole sequence uses the same config file). If
1151 it's running as \/exim/\ when it does this, all is well. However, if it
1152 happens as a consequence of a non-privileged user running \%autoreply%\,
1153 the called Exim gives up its root privilege. Then it can't write to the
1156 This means that you can't use -C (even as \/root/\) to run an instance of
1157 Exim that is going to try to run \%autoreply%\ from a process that is
1158 neither \/root/\ nor \/exim/\. Because of the architecture of Exim (using
1159 re-execs to regain privilege), there isn't any way round this
1160 restriction. Therefore, the only way you can make this scenario work is
1161 to run the \%autoreply%\ transport as \/exim/\ (that is, the user that
1162 owns the Exim spool files). This may be satisfactory for autoreplies
1163 that are essentially system-generated, but of course is no good for
1164 autoreplies from unprivileged users, where you want the \%autoreply%\
1165 transport to be run as the user. To get that to work with an alternate
1166 configuration, you'll have to use two Exim binaries, with different
1167 configuration file names in each. See S001 for a script that patches
1168 the configuration name in an Exim binary.
1171 Q0066: What does the message \*unable to set gid=xxx or uid=xxx*\ mean?
1173 A0066: This message is given when an Exim process is unable to change uid or
1174 gid when it needs to, because it does not have root privilege. This is a
1175 serious problem that prevents Exim from carrying on with what it is
1176 doing. The two most common situations where Exim needs to change uid/gid
1177 are doing local deliveries and processing users' filter files. There are
1178 two common causes of this error:
1180 (1) You have forgotten to make the exim binary setuid to \/root/\. This
1181 means that it can never change uid/gid in any situation. Also, the
1182 setuid binary must reside on a disk partition that does not have the
1183 \"nosuid"\ mount option set.
1185 (2) The exim binary is setuid, but you have configured Exim so that,
1186 while trying to verify an address at SMTP time, it runs a router
1187 that needs to change uid/gid. Because Exim runs as \/exim/\ and not
1188 \/root/\ while receiving messages, the router is unable to change
1189 uid and therefore it cannot operate. The usual example of this is a
1190 \%redirect%\ router for users' filter files.
1192 Setting the \user\ or \check_local_user\ options on a \redirect\
1193 router causes this to happen (except in the special case when the
1194 redirection list is provided by the \data\ option and does not
1195 contain \":include:"\).
1197 The solution is to set \no_verify\ on the router that is causing the
1198 problem. This means that it is skipped when an address is being
1199 verified. In ``normal'' configurations where the router is indeed
1200 handling users' filter files, this is quite acceptable, because you
1201 do not usually need to process a filter file in order to verify that
1202 the local part is valid. See, for example, the \%userforward%\
1203 router in the default configuration.
1206 Q0067: What does the error \*too many unrecognized commands*\ mean?
1208 A0067: There have been instances of network abuse involving mail sent out by
1209 web servers. In most cases, unrecognizable commands are sent as part of
1210 the SMTP session. A real MTA never sends out such invalid commands. Exim
1211 allows a few unrecognized commands in a session to permit humans who are
1212 testing to make a few typos (it responds with a 5xx error). However, if
1213 Exim receives too many such commands, it assumes that it is dealing with
1214 an abuse of some kind, and so it drops the connection.
1217 Q0068: Exim times out when trying to connect to some hosts, though those hosts
1218 are known to be up and running. What's the problem?
1220 A0068: There could be a number of reasons for this (see also Q0017). The
1221 obvious one is that there is a networking problem between the hosts.
1222 If you can ping between the hosts or connect in other ways, the problem
1223 might be caused by ECN (Explicit Congestion Notification) being enabled
1224 in your kernel. ECN uses TCP flags originally assigned to TOS - it's a
1225 "new" invention, and some hosts and routers are known to be confused if
1226 a client uses it. If you are running Linux, you can turn ECN off by
1227 running this command:
1229 ==> /bin/echo "0" > /proc/sys/net/ipv4/tcp_ecn
1231 This has also been reported to cure web connection problems from Mozilla
1232 and Netscape browsers in Linux when there were no problems with Windows
1236 Q0069: What does the error \*SMTP data timeout (message abandoned) on connection
1239 A0069: It means that there was a timeout while Exim was reading the contents of
1240 a message on an incoming SMTP connection. That is, it had successfully
1241 accepted a MAIL command, one or more RCPT commands, and a DATA command,
1242 and was in the process of reading the data itself. The length of timeout
1243 is controlled by the \smtp_receive_timeout\ option.
1245 If you get this error regularly, the cause may be incorrect handling of
1246 large packets by a router or firewall. The maximum size of a packet is
1247 restricted on some links; routers should split packets that are larger.
1248 There is a feature called ``path MTU discovery'' that enables a sender
1249 to discover the maximum packet size over an entire path (multiple
1250 Internet links). This can be broken by misconfigured firewalls and
1251 routers. There is a good explanation at \?http://www.netheaven.com/pmtu.html?\.
1252 Reducing the MTU on your local network can sometimes work round this
1253 problem. See Q0017 (3) for further discussion.
1256 Q0070: What does the error \*SMTP command timeout on connection from...*\ mean?
1258 A0070: Exim was expecting to read an SMTP command from the client, but no
1259 command was read within the \smtp_receive_timeout\ time limit.
1262 Q0071: What does the error \*failed to open DB file \(/var/spool/exim//db/retry)\:
1263 Illegal argument*\ mean?
1265 A0071: See Q0058. The cause of this error is usually the same.
1268 Q0072: Exim will deliver to normal aliases, and aliases that are pipes or
1269 files, but it objects to aliases that involve \":include:"\ items,
1270 complaining that it can't change gid or uid. Why is this?
1272 A0072: See Q0066 for a general answer. The problem happens during verification
1273 of an incoming SMTP message, not during delivery itself. In this
1274 particular case, you must have set up your aliasing router with a \user\
1275 setting. This causes Exim to change uid/gid when reading \":include:"\
1276 files. If you do not need the detailed verification provided by the
1277 router, the easy solution is to set \no_verify\ so that the router isn't
1278 used during verification.
1280 Otherwise, if you set \user\ on the router in order to provide a user
1281 for delivery to pipes or files, one solution is to put the \user\
1282 setting on the transports instead of on the router. You may need to
1283 create some special transports just for this router. The alternative is
1284 to supply two different routers, one with \user\ and \no_verify\, and
1285 the with \verify_only\ but no \user\ setting.
1288 Q0073: I'm seeing log file corruption, with parts of log lines getting mangled
1289 by other log entries.
1291 A0073: The only time this has been seen is when several servers were writing to
1292 the same log files over NFS. Exim assumes that its log file is on local
1293 disk, and using NFS, especially for more than one server, will not work.
1296 Q0074: What does the error message \*remote delivery process count got out of
1299 A0074: Exim uses subprocesses for remote deliveries; this error means that the
1300 master process expected to have a child process running, but found there
1301 were none. Prior to release 4.11, this error could be caused by running
1302 Exim under \^strace^\ on a Linux system, because stracing causes
1303 children to be ``stolen'' such that a parent that tries to wait for
1304 ``any of my children'' is told that it has none. Current releases of
1305 Exim have code to get round this problem.
1308 Q0075: I'm using LDAP, and some email addresses that contain special characters
1309 are causing parsing errors in my LDAP lookups.
1311 A0075: You should be using \"${quote_ldap:$local_part}"\ instead of just
1312 \"$local_part"\ in your lookups.
1315 Q0076: I've configured Exim to use \^syslog^\ for its logs, with the main and
1316 reject logs sent to different files, but whenever a message is rejected,
1317 I get one message on the reject log and two messages on the main log.
1319 A0076: You are probably putting your reject items into the main log as well;
1320 remember \^syslog^\ levels are inclusive (for example, \"mail.info"\
1321 includes all higher levels, so a \"mail.notice"\ message will be caught
1322 by a \"mail.info"\ descriptor).
1323 Test this by running the command:
1325 ==> logger -p mail.notice test
1327 and seeing which logs it goes into. From Exim release 4.31 it is
1328 possible to disable the rejectlog by setting \write_rejectlog\ false.
1331 Q0077: I've installed Exim and it is delivering mail just fine. However, when I
1332 try to read mail from my PC I get \*connection rejected*\ or \*unable to
1338 Q0078: Exim is logging the unknown SMTP command \"XXXX"\ from my client hosts,
1339 and they are unable to authenticate.
1341 A0078: This is a sign of a Cisco PIX firewall getting in the way. It does not
1342 support ESMTP, and turns EHLO commands into XXXX. You should configure
1343 the Pix to leave SMTP alone; see Q0053 for how to do this.
1346 Q0079: Our new PIX firewall is causing problems with incoming mail. How can
1349 A0079: See Q0053 and Q0078. If some messages get through and others do not,
1353 Q0080: Am I to understand that the database lookups must only return one value?
1354 They can not return a list of values? The documentation seems to
1355 indicate that it's possible to return a list.
1357 A0080: Lookups can be used in two different situations, and what they return is
1358 different in the two cases. (Be thankful Exim 3 is gone; there was yet
1361 (1) You can use a lookup in any expanded string. The syntax is
1363 ==> ${lookup ..... }
1365 In this case, whatever is looked up replaces the expansion item. It
1366 may be one value or a list of values. Whether a single value or a
1367 list is acceptable or not depends on where you are using the string
1368 expansion. If it is for an option that expects just one value, then
1369 only one value is allowed (for example).
1371 (2) You can make use of the lookup mechanism to test whether something
1372 (typically a host name or IP address) is in a list. For example,
1374 ==> hosts = a : b : c
1376 in an ACL tests whether the calling host's name matches ``a'', or
1377 ``b'', or ``c''. Now, suppose you want to keep the list of names in
1378 a database, or cdb file, or NIS map, or... By writing
1380 ==> hosts = pgsql;select ....
1382 you are saying to Exim: ``Run this lookup; if it succeeds, behave as
1383 if the host is in the list; if it fails, the host is not in the
1384 list.'' You are using the indexing mechanism of the database as a
1385 fast way of checking a list. A simpler example is
1387 ==> hosts = lsearch;/some/file
1389 where the file contains the list of hosts to be searched.
1391 The complication happens when a list is first expanded before being
1392 interpreted as a list. This happens in a lot of cases. You can therefore
1393 write either of these:
1395 ==> hosts = cdb;/some/file
1396 hosts = ${lookup{something}cdb{/some/file}}
1398 but they have different meanings. The first means ``see if the host name
1399 is in the list in this file''. The second means ``run this lookup and
1400 use the result of the lookup as a list of host items to check''. In the
1401 second case, the list could contain multiple values (colon separated),
1402 and one of those values could even be ``cdb;/some/file''.
1404 Flexibility does lead to complexity, I'm afraid.
1407 Q0081: What does \*error in redirect data: included file xxxx is too big*\
1410 A0081: You are trying to include a very large file in a redirection list, using
1411 the \":include:"\ feature. Exim has a built-in limit on the size, as a
1412 safety precaution. The default is 1 megabyte. If you want to increase
1413 this, you have to rebuild Exim. In your \(Local/Makefile)\, put
1415 ==> MAX_INCLUDE_SIZE = whatever
1417 and then rebuild Exim. The value is a number of bytes, but you can give
1418 it as a parenthesized arithmetic expression such as \"(3*1024*1024)"\.
1419 However, an included file of more than a megabyte is likely to be quite
1420 inefficient. How many addresses does yours contain? You get the best
1421 performance out of Exim if you arrange to send mailing list messages
1422 with no more than about 100 recipients (in order to get parallelism in
1426 Q0082: What does \*relocation error: /lib/libnss_dns.so.2: symbol
1427 __libc_res_nquery, version GLIBC_PRIVATE not defined in file
1428 libresolv.so.2 with link time reference*\ mean?
1430 A0082: You have updated \^glibc^\ while an Exim daemon is running. Stop and
1434 Q0083: Netscape on Unix is sending messages containing an unqualified user name
1435 in the ::Sender:: header line, which Exim is rejecting because I have
1436 set \"verify = header_syntax"\. How can I fix this?
1438 A0083: The only thing you can do in Exim is to set the
1439 \sender_unqualified_hosts\ option to allow unqualified sender addresses
1440 form the relevant hosts; of course, this applies to all sender
1441 addresses, not just the ::Sender:: header line.
1443 Alternatively, you can configure Netscape not to include the header line
1444 in the first place. Add the following line to the
1445 \($HOME/.netscape/preferences.js)\ and \($HOME/.netscape/liprefs.js)\
1448 ==> user_pref("mail.suppress_sender_header", true);
1450 Netscape must be shut down while doing this.
1453 Q0084: I want to set up an alias that pipes a message to \^gpg^\ and then pipes
1454 the result to \^mailx^\ to resubmit the message, but when I use my
1455 tested command in an alias file, I get an error from \^gpg^\.
1457 A0084: Probably you are using a shell command with two pipe symbols in it. An
1460 ==> gpg-xxx: "|gpg <options> | mailx <options"
1462 does not work, because Exim does not run pipes under a shell by default.
1463 You must call a shell explicitly if you want to make use of the shell's
1464 features for double-piping, either by piping to \"/bin/sh"\ with a
1465 suitable \"-c"\ option, or by piping to a shell script.
1468 Q0085: I see a lot of \*rejected EHLO ... syntactically invalid argument(s)*\.
1469 I know it's because of the underscore in the host name, but is there a
1470 switch to allow Exim to accept mail from such hosts?
1472 A0085: Yes. Add this to your configuration:
1474 ==> helo_allow_chars = _
1476 For more seriously malformed host names, see \helo_accept_junk_hosts\.
1480 Q0086: What does \*SMTP protocol violation: synchronization error (next input
1481 sent too soon)*\ mean?
1483 A0086: SMTP is a ``lock-step'' protocol, which means that, at certain points in
1484 the protocol, the client must wait for the server to respond before
1485 sending more data. Exim checks for correct behaviour, and issues this
1486 error if the client sends data too soon. This protects against
1487 malefactious clients who send a bunch of SMTP commands (usually to
1488 transmit spam) without waiting for any replies.
1490 This error is also provoked if a client unexpectedly tries to start up a
1491 TLS session immediately on connection, without using the STARTTLS
1492 command. See Q1707 for a discussion of this case.
1495 Q0087: What does \*rejected after DATA: malformed address: xx@yy may not follow
1496 <xx@yy> : failing address in "from" header*\ mean?
1498 A0087: Your DATA ACL contains
1500 ==> verify = header_syntax
1502 and an incoming message contained the line
1504 ==> From: xx@yy <xx@yy>
1506 This is syntactically invalid. The contents of an address in a header
1507 line are either just the address, or a ``phrase'' followed by an address
1508 in angle brackets. In the latter case, the ``phrase'' must be quoted if
1509 it contains special characters such as @. The following are valid
1510 versions of the bad header:
1513 From: "xx@yy" <xx@yy>
1515 though why on earth anything generates this kind of redundant nonsense I
1519 Q0088: The Windows mailer SENDFILE.EXE sometimes hangs while trying to send a
1520 message to Exim 4, and eventually times out. It worked flawlessly with
1521 Exim 3. What has changed?
1523 A0088: Exim 4 sets an obscure TCP/IP parameter called TCP_NODELAY. This
1524 disables the "Nagle algorithm" for the TCP/IP transmission. The Nagle
1525 algorithm can improve network performance in interactive situations such
1526 as a human typing at a keyboard, by buffering up outgoing data until the
1527 previous packet has been acknowledged, and thereby reducing the number
1528 of packets used. This is not relevant for mail transmission, which
1529 mostly consists of quite large blocks of data; setting TCP_NODELAY
1530 should improve performance. However, it seems that some Windows clients
1531 do not function correctly if the server turns off the Nagle algorithm.
1532 If you are using Exim 4.23 or later, you can set
1534 ==> tcp_nodelay = false
1536 This stops Exim setting TCP_NODELAY on the sockets created by the
1540 Q0089: What does the error \*kernel: application bug: exim(12099) has SIGCHLD
1541 set to SIG_IGN but calls wait()*\ mean?
1543 A0089: This was a bad interaction between a change to the Linux kernel and some
1544 ``belt and braces'' programming in Exim. The following explanation is
1545 taken from Exim's change log:
1547 When Exim is receiving multiple messages on a single connection, and
1548 spinning off delivery processess, it sets the SIGCHLD signal handling to
1549 SIG_IGN, because it doesn't want to wait for these processes. However,
1550 because on some OS this didn't work, it also has a paranoid call to
1551 \^waitpid()^\ in the loop to reap any children that have finished. Some
1552 versions of Linux now complain (to the system log) about this
1553 ``illogical'' call to \^waitpid()^\. I have therefore put it inside a
1554 conditional compilation, and arranged for it to be omitted for Linux.
1556 I am pretty sure I caught all the places in Exim where this happened.
1557 However, there are still occasional reports of this error. I have not
1558 heard of any resolutions, but my current belief is that they are caused
1559 by something that Exim calls falling foul of the same check. There was
1560 at one time a suspicion that the IPv6 stack was involved.
1563 Q0090: I can't seem to get a pipe command to run when I include a \"${lookup"\
1569 Q0091: Why is Exim giving the error \*Failed to send message from address_reply
1570 transport*\ when I run it using -C to specify an alternate
1576 Q0092: The error message \*Program received signal SIGINT, Interrupt.*\ occurs
1577 when I try to use Exim with PostgreSQL.
1579 A0092: Check that you have not set
1581 ==> log_statement=true
1583 in the PostgreSQL configuration file. It seems that this causes
1584 PostgreSQL to return logging information as the first row in a query
1585 result, which totally confuses Exim.
1589 1. BUILDING AND INSTALLING
1591 Q0101: I'm having a problem with an Exim RPM.
1593 A0101: Normally the thing to do if you have a problem with an RPM package is
1594 to contact the person who built the package first, not the person who
1595 made the software that's in the package. You can usually find out who
1596 made a package using the following command:
1598 ==> rpm --query --package --queryformat '%{PACKAGER}\n' <rpm-package-file>
1600 where \[rpm-package-file]\ is the actual file, e.g. \(exim-3.03-2.i386.rpm)\.
1601 Or, if the package is installed on your system:
1603 ==> rpm --query --queryformat '%{PACKAGER}\n' <package-name>
1605 where \[package-name]\ is the name component of the package, e.g. \"exim"\.
1606 If the packager is unable or unwilling to help, only then should you
1607 contact the actual author or associated mailing list of the software.
1609 If you discover through the querying process that you can't tell who
1610 the person (or company or group) is who built the package, or that they
1611 no longer exist at the given address, then you should reconsider
1612 whether you want a package from an unknown source on your system.
1614 If you discover through the querying process that you yourself are the
1615 person who built the package, then you should either (a) contact the
1616 author or associated mailing list, or (b) reconsider whether you ought
1617 to be building and distributing RPM packages of software you don't
1620 Similar rules of thumb govern other binary package formats, including
1621 debs, tarballs, and POSIX packages.
1624 Q0102: I can't get Exim to compile with Berkeley DB version 2.x or 3.x.
1626 A0102: Have you set \"USE_DB=yes\" in \(Local/Makefile)\? This causes Exim to use the
1627 native interface to the DBM library instead of the compatibility
1628 interface, which needs a header called \(ndbm.h)\ that may not exist on your
1632 Q0103: I'm getting an \*undefined symbol*\ error for \"hosts_ctl"\ when I try to
1633 build Exim. (On some systems this error is \*undefined reference to
1636 A0103: You should either remove the definition of \\USE_TCP_WRAPPERS\\ or add
1637 \"-lwrap"\ to your \\EXTRALIBS\\ setting in Local/Makefile.
1640 Q0104: I'm about to upgrade to a new Exim release. Do I need to ensure the
1641 spool is empty, or take any other special action?
1643 A0104: It depends on where you are coming from.
1645 (1) If you are changing to release 4.00 or later from a release prior to
1646 4.00, you will need to make changes to the run time configuration file.
1647 See the file \(doc/Exim4.upgrade)\ for details. If you are coming from
1648 before release 3.00, you should also see \(doc/Exim3.upgrade)\.
1650 (2) If you are upgrading from an Exim 4 release to a later release, you
1651 do not need to take special action. New releases are made backwards
1652 compatible with old spool files and hints databases, so that upgrading
1653 can be done on a running system. All that should be necessary is to
1654 install a new binary and then HUP the daemon.
1656 \**Warning**\: If you have changed the release of your DBM library, so
1657 that your new Exim is linked with a different release than the old one,
1658 you may encounter errors when Exim attempts to access the old hints
1659 databases. See Q0055.
1662 Q0105: What does the error \*install-info: command not found*\ mean?
1664 A0105: You have set \\INFO_DIRECTORY\\ in your \(Local/Makefile)\, and Exim is trying
1665 to install the Texinfo documentation, but cannot find the command called
1666 \(install-info)\. If you have a version of Texinfo prior to 3.9, you
1667 should upgrade. Otherwise, check your installation of Texinfo to see why
1668 the \(install-info)\ command is not available.
1671 Q0106: Exim doesn't seem to be recognizing my operating system type correctly,
1672 and so is failing to build.
1674 A0106: Run the command \"scripts/os-type -generic"\. The output should be one of
1675 the known OS types, and should correspond to your operating system. You
1676 can see which OS are supported by obeying \"ls OS/Makefile-*"\ and looking
1677 at the file name suffixes.
1679 If there is a discrepancy, it means that the script is failing to
1680 interpret the output from the \"uname"\ command correctly, or that the
1681 output is wrong. Meanwhile, you can build Exim by obeying
1683 ==> EXIM_OSTYPE=xxxx make
1685 instead of just \"make"\, provided you are running a Bourne-compatible
1686 shell, or otherwise by setting \\EXIM_OSTYPE\\ correctly in your
1687 environment. It is probably best to start again from a clean
1688 distribution, to avoid any wreckage left over from the failed attempt.
1691 Q0107: Exim fails to build, complaining about the absence of the \"killpg"\
1694 A0107: This function should be present in all modern flavours of Unix. If you
1695 are using an older version, you should be able to get round the problem
1698 ==> #define killpg(pgid,sig) kill(-(pgid),sig)
1700 into the file called \(OS/os.h-xxx)\, where xxx identifies your operating
1701 system, and is the output of the command \"scripts/os-type -generic"\.
1704 Q0108: I'm getting an unresolved symbol \"ldap_is_ldap_url"\ when trying to build
1707 A0108: You must have specified \"LOOKUP_LDAP=yes"\ in the configuration. Have you
1708 remembered to set \"-lldap"\ somewhere (e.g. in \\LOOKUP_LIBS\\)? You need that
1709 in order to get the LDAP library scanned when linking.
1712 Q0109: I'm getting an unresolved symbol \"mysql_close"\ when trying to build Exim.
1714 A0109: You must have specified \"LOOKUP_MYSQL=yes"\ in the configuration. Have you
1715 remembered to set \"-lmysqlclient"\ somewhere (e.g. in \\LOOKUP_LIBS\\)? You
1716 need that in order to get the MySQL library scanned when linking.
1719 Q0110: I'm trying to build Exim with PAM support. I have included \"-lpam"\ in
1720 \\EXTRALIBS\\, but I'm still getting a linking error:
1722 ==> /lib/libpam.so: undefined reference to `dlerror'
1723 /lib/libpam.so: undefined reference to `dlclose'
1724 /lib/libpam.so: undefined reference to `dlopen'
1725 /lib/libpam.so: undefined reference to `dlsym'
1727 A0110: Add \"-ldl"\ to \\EXTRALIBS\\. In some systems these dynamic loading functions
1728 are in their own library.
1731 Q0111: I'm getting the error \*db.h: No such file or directory*\ when I try to
1734 A0111: This problem has been seen with RedHat 7.0, but could also happen in
1735 other environments. If your system is using the DB library, you
1736 need to install the DB development package in order to build Exim.
1737 The package is called something like \"db3-devel-3.1.14-16.i386.rpm"\ for
1738 Linux systems, but you should check which version of DB you have
1739 installed (current releases are DB 4).
1742 Q0112: I'm getting the error \*/usr/bin/ld: cannot find -ldb*\ when I try to
1745 A0112: This is probably the same problem as Q0111.
1748 Q0113: I've compiled Exim and I've managed to start it but there was one
1749 problem - it always complained that \(libmsqlclient.so.10)\ was not found,
1750 even though this file is in \(/usr/local/lib/mysql/)\.
1752 A0113: Solaris: ensure you have this in your \(Local/Makefile)\:
1754 ==> LOOKUP_LIBS=-L/usr/local/lib/mysql -R/usr/local/lib/mysql
1756 Net/Open/FreeBSD: Run this command (or ensure it gets run automatically
1759 ==> ldconfig -m /usr/local/lib/mysql
1761 Linux: add \(/usr/local/lib/mysql)\ to \(/etc/ld.so.conf)\ and re-run \(ldconfig)\.
1764 ==> -Wl,-rpath -Wl,/usr/local/lib/mysql
1766 to EXTRA_LIBS and then re-link (this is similar to the Solaris solution
1767 above). This will probably also work on other systems that use GNU
1771 Q0114: How can I remove Sendmail from my system? I've built Exim and run \"make
1772 install"\, but it still doesn't seem to be fully operational.
1774 A0114: If you are running FreeBSD, see Q9201. Otherwise, you need to arrange
1775 that whichever of the paths \(/usr/sbin/sendmail)\ or \(/usr/lib/sendmail)\
1776 exists on your system is changed to refer to Exim. For example, you
1777 could use these commands (as \/root/\):
1779 ==> mv /usr/sbin/sendmail /usr/sbin/sendmail.original
1780 chmod u-s /usr/sbin/sendmail.original
1781 ln -s /path/to/exim /usr/sbin/sendmail
1783 The second command removes the setuid privilege from the old MTA, as a
1784 general safety precaution. In the third command, substitute the actual
1785 path to the Exim binary for \(/path/to/exim)\.
1788 Q0115: What does \*Can't open \(../scripts/newer)\: No such file or directory*\
1789 mean? I got it while trying to build Exim.
1791 A0115: You are using FreeBSD, or another OS that has a \^make^\ command which
1792 tries to optimize the running of commands. Exim's \(Makefile)\ contains
1793 targets with sequential commands like this:
1796 @cd pcre; $(MAKE) SHELL=$(SHELL) AR="$(AR)" $(MFLAGS) CC="$(CC)" \
1797 CFLAGS="$(CFLAGS) $(PCRE_CFLAGS)" \
1798 RANLIB="$(RANLIB)" HDRS="$(PHDRS)" \
1799 INCLUDE="$(INCLUDE) $(IPV6_INCLUDE) $(TLS_INCLUDE)"
1800 @if $(SHELL) $(SCRIPTS)/newer pcre/libpcre.a exim; then \
1801 /bin/rm -f exim eximon.bin; fi
1803 The second command assumes that the \"cd pcre"\ in the first command is
1804 no longer in effect. If you have \"-j3"\ in your default set of
1805 \"MAKEFLAGS"\, FreeBSD \^make^\ tries to optimize, and ends up up with both
1806 commands in the same shell process. The result is that \"$(SCRIPTS)"\
1807 (which has a value of \"../scripts"\) is not found.
1809 The simplest solution is to force \^make^\ to use backwards compatibility
1810 mode with each command in its own shell, by using the \-B\ flag. To
1811 ensure that this happens throughout the build, it's best to export it in
1819 Q0116: I have tried to build Exim with Berkeley DB 3 and 4, but I always get
1822 A0116: One common problem, especially when you have several different versions
1823 of BDB installed on the same host, is that the header files and library
1824 files for BDB are not in a standard place. You therefore need to tell
1825 Exim where they are, by setting INCLUDE and DBMLIB in your
1826 \(Local/Makefile)\. For example, you could use this when you want to
1829 ==> INCLUDE=-I/usr/local/include/db-4.1
1830 DBMLIB=/usr/local/lib/db-4.1/libdb.a
1832 Specifying the complete library file like this will cause it to be
1833 statically linked with Exim. You'll have to check to see where these
1834 files are on your system. For example, on FreeBSD 5, the header is in
1835 \(/usr/local/include/db4)\ and the library is in \(/usr/local/lib)\ and
1836 called \(libdb4)\. In that environment, you could use:
1838 ==> INCLUDE=-I/usr/local/include/db4
1839 DBMLIB=-L/usr/local/lib -ldb4
1841 This time, DBMLIB is specifying the library directory (\(/usr/local/lib)\)
1842 and the name of the library (\(db4)\) separately. The name of the actual
1843 library file is \(/usr/local/lib/libdb4.something)\. If the library was
1844 compiled for dynamic linking, that will be used.
1847 Q0117: Is there a quick walk-through of an Exim install from source anywhere?
1849 A0117: Here! This is a contribution from a RedHat user, somewhat edited. On
1850 other operating systems things may be slightly different, but the
1851 general approach is the same.
1853 (1) Install the db needed for Exim. This needs to be done first if you
1854 don't have a DBM library installed. Go to \?http://www.sleepycat.com?\
1855 and download \(db-4.1.25.tar.gz)\, or whatever the current release is.
1858 ==> gunzip db-4.1.25.tar.gz
1859 tar -xvf db-4.1.25.tar
1866 (2) Add a user for use by Exim, unless you want to use an existing user
1871 (3) Now you can prepare to build Exim. Go to \?http://www.exim.org?\ or
1872 one of its mirrors, or the master ftp site
1873 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4?\, and download
1874 \(exim-4.20.tar.gz)\ or whatever the current release is. Then:
1876 ==> gunzip exim-4.20.tar.gz
1877 tar -xvf exim-4.20.tar
1879 cp src/EDITME Local/Makefile
1880 cp exim_monitor/EDITME Local/eximon.conf
1882 (4) Edit \(Local/Makefile)\:
1884 Comment out EXIM_MONITOR= unless you want to install the Exim
1885 monitor (it requires X-windows).
1887 Set the user you want Exim to use for itself:
1891 If your DBM library is Berkeley DB, set up to use its native interface:
1895 Make sure Exim's build can find the DBM library and its headers. If
1896 you've installed Berkeley DB 4 you'll need to have settings like this
1897 in \(Local/Makefile)\:
1899 ==> INCLUDE=-I/usr/local/BerkeleyDB.4.1/include
1900 DBMLIB=/usr/local/BerkeleyDB.4.1/lib/libdb.a
1902 (Check that the first directory contains the db.h file and that the
1903 second library exists.)
1905 You don't need to change anything else, but you might want to review
1906 the default settings in the ``must specify'' section.
1908 (4) Build Exim by running the \/make/\ command.
1910 (5) Install Exim by running, as \/root/\:
1914 You must be \/root/\ to do this. You do not have to be root for any of
1915 the previous building activity.
1917 (6) Run some tests on Exim; see if it will do local and remote
1918 deliveries. Change the configuration if necessary (for example,
1919 uncommenting \group\ on the \%local_delivery%\ transport if you don't
1920 use a ``sticky bit'' directory).
1922 (7) Change Sendmail to Exim (of course you need to have had Sendmail
1923 installed to do this).
1925 ==> /etc/init.d/sendmail stop
1926 mv /usr/sbin/sendmail /usr/sbin/sendmail.org
1927 ln -s /usr/exim/bin/exim /usr/sbin/sendmail
1928 /etc/init.d/sendmail start
1930 (8) Check the Exim log. Either use the Exim monitor, or:
1932 ==> tail -f /var/spool/exim/log/mainlog
1935 Q0118: I've set \"LOOKUP_INCLUDE=-I/client/include"\ in Local/Makefile, but the
1936 compilation of \^exim_dumpdb^\ is ignoring this option and failing. Why?
1938 A0118: LOOKUP_INCLUDE is the special include file for lookup modules in Exim
1939 (e.g. mysql, LDAP). Confusingly, it doesn't apply to basic DBM code
1940 which is used also for other things. Try setting INCLUDE and DBMLIB
1941 instead. For example:
1944 INCLUDE=-I/client/include
1945 DBMLIB=/client/lib/libdb.a
1948 Q0119: I know there are some 3rd-party patches for Exim, for exiscan and
1949 other things. Where are they?
1951 A0119: Exiscan is at \?http://duncanthrax.net/exiscan-acl/?\.
1953 Scanexi is at \?http://w1.231.telia.com/~u23107873/scanexi.html?\
1955 A sample \^^local_scan()^^\ function for interfacing to \^uvscan^\ is
1956 at \?http://www.dcs.qmul.ac.uk/~mb/local_scan/?\.
1958 An interface to SpamAssassin at SMTP time is at
1959 \?http://marc.merlins.org/linux/exim/sa.html?\.
1961 A mini-HOWTO (PDF file) about scanning and virus scanning, and some RPMs
1962 can be found at \?http://www.timj.co.uk/linux/exim.php?\.
1965 Q0120: I'm trying to compile with LOOKUP_WHOSON, but I keep getting \*In
1966 function `whoson_find': undefined reference to `wso_query'*\.
1968 A0120: Try adding \"-lwhoson"\ to your LOOKUP_LIBS setting in \(Local/Makefile)\.
1972 2. ROUTING IN GENERAL
1974 Q0201: How can I arrange that messages larger than some limit are handled by
1977 A0201: You can use a \condition\ option on the router line this:
1979 ==> condition = ${if >{$message_size}{100K}{yes}{no}}
1982 Q0202: Can I specify a list of domains to explicitly reject?
1984 A0202: Set up a named domain list containing the domains in the first section
1985 of the configuration, for example:
1987 ==> domainlist reject_domains = list:of:domains:to:reject
1989 You can use this list in an ACL to reject any SMTP recipients in those
1990 domains. You can also give a customized error message, like this:
1992 ==> deny message = The domain $domain is no longer supported
1993 domains = +reject_domains
1995 If you also want to reject these domains in messages that are submitted
1996 from the command line (not using SMTP), you need to set up a router to
2001 domains = +reject_domains
2003 data = :fail: The domain $domain is no longer supported
2006 Q0203: How can I arrange to do my own qualification of non-fully-qualified
2007 domains, and then pass them on to the next router?
2009 A0203: If you have some list of domains that you want to qualify, you can do
2010 this using a redirect router. For example,
2015 data = ${quote:$local_part}@$domain.c.com
2017 This adds \".c.com"\ to any domain that matches \"*.a.b"\.
2018 If you want to do this in conjunction with a \%dnslookup%\ router, the
2019 \widen_domains\ option of that router may be another way of achieving
2023 Q0204: Every system has a \"nobody"\ account under which httpd etc run. I would
2024 like to know how to restrict mail which comes from that account to users
2027 A0204: Set up a first router like this:
2031 senders = nobody@your.domain
2032 domains = ! +local_domains
2034 data = :fail: Nobody may not mail off-site
2036 This assumes you have defined \+local_domains\ as in the default
2040 Q0205: How can I get Exim to deliver to me locally and everyone else at the same
2041 domain via SMTP to the MX record specified host?
2043 A0205: Create an \%accept%\ router to pick off the one address and pass it to
2044 an appropriate transport. Put this router before the one that does MX
2051 transport = local_delivery
2053 In the transport you will have to specify the \user\ option. An
2054 alternative way of doing this is to add a condition to the router that
2055 does MX lookups to make it skip your address. Subsequent routers can then
2056 deliver your address locally. You'll need a condition like this:
2059 ${if and {{eq{$domain}{dom.com}}{eq{$local_part}{me}}}{no}{yes}}
2062 Q0206: How can I get Exim to deliver certain domains to a different SMTP port
2065 A0206: You must set up a special \%smtp%\ transport, where you can specify the
2066 \port\ option, and then set up a router to route the domains to that
2067 transport. There are two possibilities for specifying the host:
2069 (1) If you use a \%manualroute%\ router, you can specify the local host
2070 in the router options. You must also set
2074 so that it does not object to sending to the local host.
2076 (2) If you use a router that cannot specify hosts (for example, an
2077 \%accept%\ router with appropriate conditions), you have to specify
2078 the host using the \hosts\ option of the transport. In this case,
2079 you must also set \allow_localhost\ on the transport.
2082 Q0207: Why does Exim lower-case the local-part of a non-local domain when
2085 A0207: Because \caseful_local_part\ is not set (in the default configuration)
2086 for the \%dnslookup%\ router. This does not matter because the local
2087 part takes no part in the routing, and the actual local part that is
2088 sent out in the RCPT command is always the original local part.
2091 Q0208: I can't get a lookup to work in a domain list. I'm trying this:
2093 ==> domainlist local_domains = @:localhost:${lookup pgsql{SELECT ...
2095 A0208: Does the lookup return a colon separated list of domains? If not, you
2096 are using the wrong kind of lookup. The most common way of using a
2097 lookup in a domain list is something like this:
2099 ==> domainlist local_domains = @:localhost:pgsql;SELECT ...
2101 Using that syntax, if the query succeeds, the domain is considered to be
2102 in the list. The value that is returned is not relevant.
2106 3. ROUTING TO REMOTE HOSTS
2108 Q0301: What do \*lowest numbered MX record points to local host*\ and \*remote
2109 host address is the local host*\ mean?
2111 A0301: They mean exactly what they say. Exim expected to route an address to a
2112 remote host, but the IP address it obtained from a router was for the
2113 local host. If you really do want to send over TCP/IP to the local host
2114 (to a different version of Exim or another MTA, for example), see Q0206.
2116 More commonly, these errors arise when Exim thinks it is routing some
2117 foreign domain. For example, the router configuration causes Exim to
2118 look up the domain in the DNS, but when Exim examines the DNS output,
2119 either the lowest numbered MX record points at the local host, or there
2120 are no MX records, and the address record for the domain contains an
2121 IP address that belongs to the local host.
2123 There has been a rash of instances of domains being deliberately set up
2124 with MX records pointing to \"localhost"\ (or other names with A records
2125 that specify 127.0.0.1), which causes this behaviour. You can use the
2126 \ignore_target_hosts\ option to get Exim to ignore these records. The
2127 default contiguration does this. For more discussion, see Q0319. For
2130 (1) If the domain is meant to be handled as a local domain, there
2131 is a problem with the configuration, because it should not then have
2132 been looked up in the DNS. Check the \domains\ settings on your
2135 (2) If the domain is one for which the local host is providing a
2136 relaying service (called ``mail hubbing''), possibly as part of a
2137 firewall, you need to set up a router to tell Exim where to send
2138 messages addressed to this domain, because the DNS directs them to
2139 the local host. You should put a router like this one before the one
2140 that does DNS lookups:
2143 driver = manualroute
2144 transport = remote_smtp
2145 route_list = see discussion below
2147 The contents of the \route_list\ option depend on how many hosts you
2148 are hubbing for, and how their names are related to the domain name.
2149 Suppose the local host is a firewall, and all the domains in
2150 \(*.foo.bar)\ have MX records pointing to it, and each domain
2151 corresponds to a host of the same name. Then the setting could be
2153 ==> route_list = *.foo.bar $domain
2155 If there isn't a convenient relationship between the domain names
2156 and the host names, you either have to list each domain separately,
2157 or use a lookup expansion to look up the host from the domain, or
2158 put the routing information in a file and use the \route_data\
2159 option with a lookup expansion.
2161 (3) If neither (1) nor (2) is the case, the lowest numbered MX record or
2162 the address record for the domain should not be pointing to your
2163 host. You should arrange to get the DNS mended.
2166 Q0302: Why does Exim say \*all relevant MX records point to non-existent hosts*\
2167 when MX records point to IP addresses?
2169 A0302: MX records cannot point to IP addresses. They are defined to point to
2170 host names, so Exim always interprets them that way. (An IP address is a
2171 syntactically valid host name.) The DNS for the domain you are having
2172 problems with is misconfigured.
2174 However, it appears that more and more DNS zones are breaking the rules
2175 and putting IP addresses on the RHS of MX records. Exim follows the
2176 rules and rejects this, but other MTAs do support it, so the
2177 \allow_mx_to_ip\ was regretfully added at release 3.14 to permit this
2181 Q0303: How do I configure Exim to send all messages to a central server? I
2182 don't want to do any local deliveries at all on this host.
2184 A0303: Use this as your first and only router:
2186 ==> send_to_gateway:
2187 driver = manualroute
2188 transport = remote_smtp
2189 route_list = * central.server.host
2192 Q0304: How do I configure Exim to send all non-local mail to a gateway host?
2194 A0304: Replace the \%dnslookup%\ router in the default configuration with the
2197 ==> send_to_gateway:
2198 driver = manualroute
2199 domains = !+local_domains
2200 transport = remote_smtp
2201 route_list = * gate.way.host
2203 If there are several hosts you can send to, you can specify them as a
2204 colon-separated list.
2207 Q0305: How can I arrange for mail on my local network to be delivered directly
2208 to the relevant hosts, but all other mail to be sent to my ISP's mail
2209 server? The local hosts are all DNS-registered and behave like normal
2212 A0305: Set up a first router to pick off all the domains for your local
2213 network. There are several ways you might do this. For example
2217 transport = remote_smtp
2218 domains = *.mydomain.com
2220 This does a perfectly conventional DNS routing operation, but only for
2221 the domains that match \(*.mydomain.com)\. Follow this with a `smart
2225 driver = manualroute
2226 domains = !+local_domains
2227 transport = remote_smtp
2228 route_list = * mail.isp.net
2230 This routes any other non-local domains to the smart host.
2233 Q0306: How do I configure Exim to send all non-local mail to a central server
2234 if it cannot be immediately delivered by my host? I don't want to have
2235 queued mail waiting on my host.
2237 A0306: Add to the \%remote_smtp%\ transport the following:
2239 ==> fallback_hosts = central.server.name(s)
2241 If there are several names, they must be separated by colons.
2244 Q0307: The \route_list\ setting \"^foo$:^bar$ $domain"\ in a \%manualroute%\
2245 router does not work.
2247 A0307: The first thing in a \route_list\ item is a single pattern, not a list of
2248 patterns. You need to write that as \"^(foo|bar)$ $domain"\.
2249 Alternatively, you could use several items and write
2251 ==> route_list = foo $domain; bar $domain
2253 Note the semicolon separator. This is because the second thing in each
2254 item can itself be a colon-separated list of hosts.
2257 Q0308: I have a domain for which some local parts must be delivered locally,
2258 but the remainder are to be treated like any other remote addresses.
2260 A0308: One possible way of doing this is as follows: Assuming you are using a
2261 configuration that is similar to the default one, first exclude your
2262 domain from the first router by changing it to look like this:
2264 ==> non_special_remote:
2266 domains = ! +local_domains : ! special.domain
2267 transport = remote_smtp
2268 ignore_target_hosts = 127.0.0.0/8
2271 Then add a second router to handle the local parts that are not to
2272 be delivered locally:
2276 domains = special.domain
2277 local_parts = ! lsearch;/list/of/special/localparts
2278 transport = remote_smtp
2279 ignore_target_hosts = 127.0.0.0/8
2282 The remaining local parts will fall through to the remaining routers,
2283 which can delivery them locally.
2286 Q0309: How can I configure Exim on a firewall machine so that if mail arrives
2287 addressed to a domain whose MX points to the firewall, it is forwarded
2288 to the internal mail server, without having to have a list of all the
2291 A0309: As your first router, have the standard \%dnslookup%\ router from the
2292 default configuration, with the added option
2296 This will handle all domains whose lowest numbered MX records do not
2297 point to your host. Because of the \no_more\ setting, if it encounters
2298 an unknown domain, routing will fail. However, if it hits a domain whose
2299 lowest numbered MX points to your host, the \self\ option comes into
2300 play, and overrides \no_more\. The \"pass"\ setting causes it to pass
2301 the address on to the next router. (The default causes it to generate an
2304 The only non-local domains that reach the second router are those with
2305 MX records pointing to the local host. Set it up to send them to the
2306 internal mail server like this:
2309 driver = manualroute
2310 domains = ! +local_domains
2311 transport = remote_smtp
2312 route_list = * internal.server
2315 Q0310: If a DNS lookup returns no MX records why doesn't Exim just bin the
2318 A0310: If a DNS lookup returns no MXs, Exim looks for an address record, in
2319 accordance with the rules that are defined in the RFCs. If you want to
2320 break the rules, you can set \mx_domains\ in the \%dnslookup%\ router, but
2321 you will cut yourself off from those sites (and there still seem to be
2322 plenty) who do not set up MX records.
2325 Q0311: When a DNS lookup for MX records fails to complete, why doesn't Exim
2326 send the messsage to the host defined by the A record?
2328 A0311: The RFCs are quite clear on this. Only if it is known that there are no
2329 MX records is an MTA allowed to make use of the A record. When an MX
2330 lookup fails to complete, Exim does not know whether there are any MX
2331 records or not. There seem to be some name servers (or some
2332 configurations of some name servers) that give a ``server fail'' error when
2333 asked for a non-existent MX record. Exim uses standard resolver calls,
2334 which unfortunately do not distinguish between this case and a timeout,
2335 so all Exim can do is try again later.
2338 Q0312: Is it possible to use a conditional expression for the host item in a
2339 \route_list\ for \%manualroute%\ router? I tried the following, but it
2342 ==> route_list = * ${if match{$header_from:}{\N.*\.usa\.net$\N} \
2343 {<smarthost1>}{<smarthost2>}
2345 A0312: The problem is that the second item in \route_list\ contains white
2346 space, which means that it gets terminated prematurely. To avoid this,
2347 you must put the second item in quotes:
2349 ==> route_list = * "${if match{$header_from:}{\N.*\.usa\.net$\N} \
2350 {<smarthost1>}{<smarthost2>}}"
2353 Q0313: I send all external mail to a smart host, but this means that bad
2354 addresses also get passed to the smart host. Can I avoid this?
2356 A0313: Assuming you have DNS availability, set up a conventional \%dnslookup%\
2357 router to do the routing, but in the \%remote_smtp%\ transport set this:
2359 ==> hosts = your.smart.host
2362 This will override the hosts that the router finds so that everything
2363 goes to the smart host, but any non-existent domains will be failed by
2367 Q0314: I have a really annoying intermittent problem where attempts to mail to
2368 valid sites are rejected with \*unknown mail domain*\. This only happens a
2369 few times a day and there is no particular pattern to the sites it
2370 rejects. If I try to lookup the same domain a few minutes later then it
2373 A0314: This is almost certainly a problem with the DNS resolver or the the
2374 domain's name servers.
2376 (1) Have you linked Exim against the newest DNS resolver library that
2377 comes with Bind? If you are using SunOS4 that may be your problem, as
2378 the resolver that comes with that OS is known to be buggy and to give
2379 intermittent false negatives.
2381 (2) Effects like this are sometimes seen if a domain's name servers get
2382 out of step with each other.
2385 Q0315: I'd like route all mail with addresses that can't be resolved (the DNS
2386 lookup times out) to a relay machine.
2388 A0315: Set \pass_on_timeout\ on your \%dnslookup%\ router, and add below it a
2389 \%manualroute%\ router that routes all relevant domains to the relay.
2392 Q0316: I would like to forward all incoming email for a particular domain to
2393 another host via SMTP. Whereabouts would I configure that?
2395 A0316: Use this as your first router:
2398 driver = manualroute
2399 transport = remote_smtp
2400 route_list = the.particular.domain the.other.host
2402 You will also need to adjust the ACL for incoming SMTP so that this
2403 domain is accepted for relaying. If you are using the default
2404 configuration, there is a domain list called \relay_domains\ that is
2408 Q0317: What I'd like to do is have alternative smart hosts, where the one to be
2409 used is determined by which ISP I'm connected to.
2411 A0317: The simplest way to do this is to arrange for the name of the smart host
2412 du jour to be placed in a file when you connect, say \(/etc/smarthost)\.
2413 Then you can read this file from a \%manualroute%\ router like this:
2416 driver = manualroute
2417 transport = remote_smtp
2418 route_list = * ${readfile{/etc/smarthost}{}}
2420 The second argument of the \"readfile"\ item is a string that replaces
2421 any newline characters in the file (in this case, with nothing).
2422 By keeping the data out of the main configuration file, you avoid having
2423 to HUP the daemon when it changes.
2426 Q0318: Exim won't route to a host with no MX record.
2428 A0318: More than one thing may cause this.
2430 (1) Are you sure there really is no MX record? Sometimes a typo results
2431 in a malformed MX record in the zone file, in which case some name
2432 servers give a SERVFAIL error rather than NXDOMAIN. Exim has to treat
2433 this as a temporary error, so it can't go on to look for address records.
2434 You can check for this state using one of the DNS interrogation commands,
2435 such as \(nslookup)\, \(host)\, or \(dig)\.
2437 (2) Is there a wildcard MX record for \(your)\ domain? Is the
2438 \search_parents\ option on in your \%dnslookup%\ router? If the answer to
2439 both these questions is ``yes'', that is the cause of the problem. When
2440 the DNS resolver fails to find the MX record, it tries adding on your
2441 domain if \search_parents\ is true, and thereby finds your wildcard MX
2442 record. For example:
2444 . There is a wildcard MX record for \(*.a.b.c)\.
2446 . There is a host called \(x.y.z)\ that has an A record and no MX record.
2448 . Somebody on the host \(m.a.b.c)\ domain tries to mail to \(user@x.y.z)\.
2450 . Exim calls the DNS to look for an MX record for \(x.y.z)\.
2452 . The DNS doesn't find any MX record. Because \search_parents\ is true,
2453 it then tries searching the current host's parent domain, so it
2454 looks for \(x.y.z.a.b.c)\ and picks up the wildcard MX record.
2456 Setting \search_parents\ false makes this case work while retaining the
2457 wildcard MX record. However, anybody on the host \(m.a.b.c)\ who mails to
2458 \(user@n.a)\ (expecting it to go to \(user@n.a.b.c)\) now has a problem. The
2459 \widen_domains\ option of the \%dnslookup%\ router may be helpful in this
2463 Q0319: I have some mails on my queues that are sticking around longer than
2464 the retry time indicates they should. They are all getting frozen
2465 because some remote admin has set their MX record to 127.0.0.1.
2467 A0319: The admin in question is an idiot. Exim will always freeze such messages
2468 because they are apparently routed to the local host. To bounce these
2469 messages immediately, set
2471 ==> ignore_target_hosts = 127.0.0.1
2473 on the \%dnslookup%\ router. This causes Exim to completely ignore any hosts
2474 with that IP address. In fact, there are quite a number of IP addresses
2475 that should never be used. Here is a suggested configuration list for
2478 ==> # Don't allow domains whose single MX (or A) record is a
2479 # "special-use IPv4 address", as listed in RFC 3330.
2480 ignore_target_hosts = \
2481 # Hosts on "this network"; RFC 1700 (page 4) states that these
2482 # are only allowed as source addresses
2484 # Private networks, RFC 1918
2485 10.0.0.0/8 : 172.16.0.0/12 : 192.168.0.0/16 : \
2486 # Internet host loopback address, RFC 1700 (page 5)
2488 # "Link local" block
2490 # "TEST-NET" - should not appear on the public Internet
2492 # 6to4 relay anycast addresses, RFC 3068
2494 # Network interconnect device benchmark testing, RFC 2544
2496 # Multicast addresses, RFC 3171
2498 # Reserved for future use, RFC 1700 (page 4)
2502 Q0320: How can I arrange for all mail to \*user@some.domain*\ to be forwarded
2503 to \*user@other.domain*\?
2505 A0320: Put this as your first router:
2509 domains = some.domain
2510 data = ${quote:$local_part}@other.domain
2513 Q0321: How can I tell an Exim router to use only IPv4 or only IPv6 addresses
2514 when it finds both types in the DNS?
2516 A0321: You can do this by making it ignore the addresses you don't want. This
2517 example ignores all IPv6 addresses and all IPv4 addresses in the 127
2520 ==> ignore_target_hosts = <; 0000::0000/0 ; 127.0.0.0/8
2522 To ignore all IPv4 addresses, use
2524 ==> ignore_target_hosts = 0.0.0.0/0
2526 See Q0319 for a general discussion of \ignore_target_hosts\.
2529 Q0322: How can I reroute all messages bound for 192.168.10.0 and 10.0.0.0 to
2530 a specific mail server?
2532 A0322: That is an odd requirement. However, there is an obscure feature in
2533 Exim, originally implemented for packet radio people, that perhaps can
2534 help. Check out the \translate_ip_address\ generic router option.
2538 4. ROUTING FOR LOCAL DELIVERY
2540 Q0401: I need to have any mail for \(virt.dom.ain)\ that doesn't match one of the
2541 aliases in \(/usr/lib/aliases.virt)\ delivered to a particular address, for
2542 example, \(postmaster@virt.dom.ain)\.
2544 A0401: Adding an asterisk to a search type causes Exim to look up ``*'' when the
2545 normal lookup fails. So if your aliasing router is something like this:
2549 domains = virt.dom.ain
2550 data = ${lookup{$local_part}lsearch{/usr/lib/aliases.virt}}
2553 you should change \"lsearch"\ to \"lsearch*"\, and put this in the alias
2556 ==> *: postmaster@virt.dom.ain
2558 This solution has the feature that if there are several unknown
2559 addresses in the same message, only one copy gets sent to the
2560 postmaster, because of Exim's normal de-duplication rules.
2562 NOTE: This solution works only if there is also an entry for \(postmaster)\
2563 in the alias file, ultimately resolving to an address that is not in
2564 \(virt.dom.ain)\. See also Q0434.
2567 Q0402: How do I arrange for all incoming email for \(*@some.domain)\ to go into one
2568 pop3 mail account? The customer doesn't want to add a list of specific
2569 local parts to the system.
2571 A0402: Set up a special transport that writes to the mailbox like this:
2573 ==> special_transport:
2581 The file will be written as the user \"exim"\. Then arrange to route all
2582 mail for that domain to that transport, with a router like this:
2586 domains = some.domain
2587 transport = special_transport
2590 Q0403: How do I configure Exim to send messages for unknown local users to a
2593 A0403: Assuming you are using something like the default configuration, where
2594 local users are processed by the later routers, you should add the
2595 following router at the end:
2598 driver = manualroute
2599 transport = remote_smtp
2600 route_list = * server.host.name
2603 However, you should if possible try to verify that the user is known on
2604 the central server before accepting the message in the first place. This
2605 can be done by making use of Exim's ``call forward'' facility.
2608 Q0404: How can I arrange for messages submitted by (for example) Majordomo to
2609 be handled specially?
2611 A0404: You can use the \condition\ option on a router, with a setting such as
2613 ==> condition = ${if and {{eq {$sender_host_address}{}} \
2614 {eq {$sender_ident}{majordom}}} {yes}{no}}
2616 This first tests for a locally-submitted message, by ensuring there is
2617 no sending host address, and then it checks the identity of the user
2618 that ran the submitting process.
2621 Q0405: On a host that accepts mail for several domains, do I have to use fully
2622 qualified addresses in \(/etc/aliases)\ or do I have to set up an alias
2623 file for each domain?
2625 A0405: You can do it either way. The default aliasing router contains this line:
2627 ==> data = ${lookup{$local_part}lsearch{/etc/aliases}}
2629 which is what does the actual lookup. To make it look up the complete
2630 address instead of just the local part, use
2632 ==> data = ${lookup{$local_part@$domain}lsearch{/etc/aliases}}
2634 If you want to use a separate file for each domain, use
2636 ==> data = ${lookup{$local_part}lsearch{/etc/aliases/$domain}}
2639 Q0406: Some of my users are using the \(.forward)\ to pipe to a shell command which
2640 appends to the user's INBOX. How can I forbid this?
2642 A0406: If you allow your users to run shells in pipes, you cannot control which
2643 commands they run or which files they write to. However, you should point
2644 out to them that writing to an INBOX by arbitrary commands is not
2645 interlocked with the MTA and MUAs, and is liable to mess up the contents
2648 If a user simply wants to choose a specific file for the delivery of
2649 messages, this can be done by putting a file name in a \(.forward)\ file
2650 rather than using a pipe, or by using the \"save"\ command in an Exim
2653 You can set \forbid_pipe\ on the router, but that will prevent them from
2654 running any pipe commands at all. Alternatively, you can restrict which
2655 commands they may run in their pipes by setting the \allow_commands\
2656 and/or \restrict_to_path\ options in the \%address_pipe%\ transport.
2659 Q0407: How can I arrange for a default value when using a query-style lookup
2660 such as LDAP or NIS+ to handle aliases?
2662 A0407: Use a second query in the failure part of the original lookup, like
2665 ==> data = ${lookup ldap\
2666 {ldap://x.y.z/l=yvr?aliasaddress?sub?(&(mail=$local_part@$domain))}\
2670 {ldap://x.y.z/l=yvr?aliasaddress?sub?(&(mail=default@$domain))}}\
2673 Of course, if the default is a fixed value you can just include it
2677 Q0408: If I don't fully qualify the addresses in a virtual domain's alias file
2678 then mail to aliases which also match the local domain get delivered to
2681 A0408: Set the \qualify_preserve_domain\ option on the \%redirect%\ router.
2684 Q0409: I want mail for any local part at certain virtual domains to go
2685 to a single address for each domain.
2687 A0409: One way to to this is
2691 data = ${lookup{$domain}lsearch{/etc/virtual}}
2693 The \(/etc/virtual)\ file contains a list of domains and the addresses to
2694 which their mail should be sent. For example:
2696 ==> domain1: postmaster@some.where.else
2697 domain2: joe@xyz.plc
2699 If the number of domains is large, using a DBM or cdb file would be more
2700 efficient. If the lookup fails to find the domain in the file, the value
2701 of the \data\ option is empty, causing the router to decline.
2704 Q0410: How can I make Exim look in the alias NIS map instead of \(/etc/aliases)\?
2706 A0410: The default configuration does not use NIS (many hosts don't run it).
2707 You need to change this line in the \%system_aliases%\ router:
2709 ==> data = ${lookup{$local_part}lsearch{/etc/aliases}}
2713 ==> data = ${lookup{$local_part}nis{mail.aliases}}
2715 If you want to use \(/etc/aliases)\ as well as NIS, put this router (with
2716 a different name) before or after the default one, depending on which
2717 data source you want to take precedence.
2720 Q0411: Why will Exim deliver a message locally to any username that is longer
2721 than 8 characters as long as the first 8 characters match one of the
2724 A0411: The problem is in your operating system. Exim just calls the \^^getpwnam()^^\
2725 function to test a local part for being a local login name. It does not
2726 presume to guess the maximum length of user name for the underlying
2727 operating system. Many operating systems correctly reject names that are
2728 longer than the maximum length; yours is apparently deficient in this
2729 regard. To cope with such systems, Exim has an option called
2730 \max_user_name_length\ which you can set to the maximum allowed length.
2733 Q0412: Why am I seeing the error \*bad mode (100664) for /home/test/.forward*\?
2734 I've looked through the documentation but can't see anything to suggest
2735 that Exim has to do anything other than read the \(.forward)\ file.
2737 A0412: For security, Exim checks for mode bits that shouldn't be set, by
2738 default 022. You can change this by setting the \modemask\ option of the
2739 \%redirect%\ router that is handling \(.forward)\ files.
2742 Q0413: When a user's \(.forward)\ file is syntactially invalid, Exim defers
2743 delivery of all messages to that user, which sometimes include the
2744 user's own test messages. Can it be told to ignore the \(.forward)\ file
2745 and/or inform the user of the error?
2747 A0413: Setting \skip_syntax_errors\ on the redirect router causes syntax
2748 errors to be skipped. When dealing with users' \(.forward)\ files it is best
2749 to combine this with a setting of \syntax_errors_to\ in order to send
2750 a message about the error to the user. However, to avoid an infinite
2751 cascade of messages, you have to be able to send to an address that
2752 bypasses \(.forward)\ file processing. This can be done by including a
2753 router like this one
2758 transport = local_delivery
2761 before the \%redirect%\ router that handles \(.forward)\ files. This will
2762 do an ordinary local delivery without \(.forward)\ processing, if the
2763 local part is prefixed by \"real-"\. You can then set something like
2764 the following options on the \%redirect%\ router:
2766 ==> skip_syntax_errors
2767 syntax_errors_to = real-$local_part@$domain
2768 syntax_errors_text = "\
2769 This is an automatically generated message. An error has been \
2770 found\nin your .forward file. Details of the error are reported \
2771 below. While\nthis error persists, messages addressed to you will \
2772 get delivered into\nyour normal mailbox and you will receive a \
2773 copy of this message for\neach one."
2775 A final tidying setting to go with this is a rewriting rule that changes
2776 \"real-username"\ into just \"username"\ in the headers of the message:
2778 ==> \N^real-([^@]+)@your\.dom\.ain$\N $1@your.dom.ain h
2780 This means that users won't ever see the \"real-"\ prefix, unless they
2781 look at the ::Envelope-To:: header.
2784 Q0414: I have set \caseful_local_part\ on the routers that handle my local
2785 domain because my users have upper case letters in their login names,
2786 but incoming mail now has to use the correct case. Can I relax this
2789 A0414: If you really have to live with caseful user names but want incoming
2790 local parts to be caseless, then you have to maintain a file, indexed by
2791 the lower case forms, that gives the correct case for each login, like
2800 and at the start of the routers that handle your local domain, put one
2803 ==> set_case_router:
2805 data = ${lookup{${lc:$local_part}}lsearch{/the/file}}
2806 qualify_preserve_domain
2808 For efficiency, you should also set the \redirect_router\ option to cause
2809 processing of the changed address to begin at the next router. If you
2810 are otherwise using the default configuration, the setting would be
2812 ==> redirect_router = system_aliases
2814 If there are lots of users, then a DBM or cdb file would be more
2815 efficient than a linear search. If you are handling several domains,
2816 you will have to extend this configuration to cope appropriately.
2819 Q0415: Can I use my existing alias files and forward files as well as procmail
2820 and effectively drop in Exim in place of Sendmail ?
2822 A0415: Yes, as long as your alias and forward files don't assume that pipes are
2823 going to run under a shell. If they do, you either have to change them,
2824 or configure Exim to use a shell (which it doesn't by default).
2827 Q0416: What is quickest way to set up Exim so any message sent to a
2828 non-existing user would bounce back with a different message, based
2829 on the name of non-existing user?
2831 A0416: Place this router last, so that it catches any local addresses that
2832 are not otherwise handled:
2836 transport = non_exist_reply
2839 Then add the following transport to the transports section:
2841 ==> non_exist_reply:
2844 to = $sender_address
2845 subject = User does not exist
2846 text = You sent mail to $local_part. That's not a valid user here. \
2847 The subject was: $subject.
2849 If you want to pick up a message from a file, you can use the \file\
2850 option (use \file_expand\ if you want its contents expanded).
2853 Q0417: What do I need to do to make Exim handle \(/usr/ucb/vacation)\ processing
2854 automatically, so that people could just create a \(.vacation.msg)\ file in
2855 their home directory and not have to edit their \(.forward)\ file?
2857 A0417: Add a new router like this, immediately before the normal \%localuser%\
2863 require_files = $home/.vacation.msg
2864 transport = vacation_transport
2867 and a matching new transport like this:
2869 ==> vacation_transport:
2871 command = /usr/ucb/vacation $local_part
2873 However, some versions of \(/usr/ucb/vacation)\ do not work properly unless
2874 the DBM file(s) it uses are created in advance - it won't create them
2875 itself. You also need a way of removing them when the vacation is over.
2877 Another possibility is to use a fixed filter file which is run whenever
2878 \(.vacation.msg)\ exists, for example:
2883 require_files = $home/.vacation.msg
2884 file = /some/central/filter
2887 The filter file should use the \"if personal"\ check before sending mail,
2888 to avoid generating automatic responses to mailing lists. If sending a
2889 message is all that it does, this doesn't count as a ``significant''
2890 delivery, so the original message goes on to be delivered as normal.
2892 Yet another possibility is to make use of Exim's \%autoreply%\ transport,
2893 and not use \(/usr/ucb/vacation)\ at all.
2896 Q0418: I want to use a default entry in my alias file to handle unknown local
2897 parts, but it picks up the local parts that the aliases generate. For
2898 example, if the alias file is
2900 ==> luke.skywalker: luke
2904 then messages addressed to \/luke.skywalker/\ end up at \/postmaster/\.
2906 A0418: The default mechanism works best with virtual domains, where the
2907 generated address is not in the same domain. If you just want to pick up
2908 all unknown local parts and send them to postmaster, an easier way to do
2909 it is to put this as your last router:
2916 Another possibility is to put the redirect router for these aliases
2917 after all the other routers, so that local parts which are user names
2918 get picked off first. You will need to have two aliasing routers if
2919 there are some local parts (e.g. \/root/\) which are login names, but which
2920 you want to handle as aliases.
2923 Q0419: I have some obsolete domains which people have been warned not to use
2924 any more. How can I arrange to delete any mail that is sent to them?
2926 A0419: To reject them at SMTP time, with a customized error message, place
2927 statments like this in the ACL:
2929 ==> deny message = The domain $domain is obsolete
2930 domains = lsearch;/etc/exim/obsolete.domains
2932 For messages that don't arrive over SMTP, you can use a router like
2933 this to bounce them:
2937 domains = lsearch;/etc/exim/obsolete.domains
2939 data = :fail: the domain $domain is obsolete
2941 If you just want to throw away mail to those domains, accept them at
2942 SMTP time, and use a router like this:
2945 domains = lsearch;/etc/exim/obsolete.domains
2949 Q0420: How can I arrange that mail addressed to \(anything@something.mydomain.com)\
2950 gets delivered to \(something@mydomain.com)\?
2952 A0420: Set up a router like this:
2954 ==> user_from_domain:
2956 data = ${if match{$domain}{\N^(.+)\.mydomain\.com$\N}\
2960 Q0421: I can't get a regular expression to work in a \local_parts\ option on
2963 A0421: Have you remembered to protect any backslash and dollar characters in
2964 your regex from unwanted expansion? The easiest way is to use the
2965 \"@\N"\ facility, like this:
2967 ==> local_parts = \N^0740\d{6}\N
2970 Q0422: How can I arrange for all addresses in a group of domains \(*.example.com)\
2971 to share the same alias file? I have a number of such groups.
2973 A0422: For a single group you could just hard wire the file name into a router
2976 ==> domains = *.example.com
2978 set, to restrict it to the relevant domains. For a number of such groups
2979 you can create a file containing the domains, like this:
2981 ==> *.example1.com example1.com
2982 *.example2.com example2.com
2985 Then create a router like this
2989 domains = partial-lsearch;/that/file
2990 data = ${lookup{$local_part}lsearch*{/etc/aliases.d/$domain_data}}
2992 The variable \$domain_data$\ contains the data that was looked up when the
2993 \domains\ option was matched, i.e. \"example1.com"\, \"example2.com"\, etc.
2997 Q0423: Some of our users have no home directories; the field in the password
2998 file contains \(/no/home/dir)\. This causes the error \*failed to stat
2999 /no/home/dir (No such file or directory)*\ when Exim tries to look for a
3000 \(.forward file)\, and the delivery is deferred.
3002 A0423: There are two issues involved here:
3004 (1) With the default configuration, you are asking Exim to check for a
3005 \(.forward)\ file in the user's home directory. If no file is found,
3006 Exim tries to \^^stat()^^\ the home directory. This is so that it will
3007 notice a missing NFS home directory, and not treat it as if the
3008 \(.forward)\ file did not exist. This \^^stat()^^\ is failing when the
3009 home directory really doesn't exist. You should arrange for the
3010 \%userforward%\ router not to run for these special users, by adding
3013 ==> condition = ${if eq {$home}{/no/home/dir}{no}{yes}}
3015 (2) If you use \check_local_user\ on another router to route to a local
3016 transport (again, this is what is in the default configuration), you
3017 will also have to specify a current directory for the transport, because
3018 by default it makes the home directory current. This is easily done by
3021 ==> current_directory = /
3025 ==> transport_current_directory = /
3027 to the router. Or you can add \home_directory\ to the transport, because
3028 the current directory defaults to the home directory.
3031 Q0424: How can I disable Exim's de-duplication features? I want it to do two
3032 deliveries if two different aliases expand to the same address.
3034 A0424: This is not possible. Duplication has other ramifications other than
3035 just (in)convenience. Consider:
3037 . Message is addressed to A and to B.
3039 . Both A and B are aliased to C.
3041 . Without de-duplication, two deliveries to C are scheduled.
3043 . One delivery happens, Exim records that it has delivered the message
3046 . The next delivery fails (C's mailbox is over quota, say).
3048 Next time round, Exim wants to know if it has already delivered to C or
3049 not, before scheduling a new delivery. Has it? Obviously, if duplicate
3050 deliveries are supported, it has to remember not only that it has
3051 delivered to C but also the ``history'' of how that delivery happened - in
3052 effect an ancestry list back to the original envelope address. This it
3053 does not do, and changing it to work in that way would be a lot of work
3056 The best way to get duplicate deliveries if you want them is not to use
3057 aliases, but to route the addresses directly to a transport, e.g.
3061 local_parts = lsearch;/etc/list/of/special/local/parts
3062 transport = local_delivery
3066 Q0425: My users' mailboxes are distributed between several servers according to
3067 the first letter of the user name. All the servers receive incoming mail
3068 at random. I would like to have the same configuration file for all the
3069 servers, which does local delivery for the mailboxes it holds, and sends
3070 other addresses to the correct other server. Is this possible?
3072 A0425: It is easiest if you arrange for all the users to have password entries
3073 on all the servers. This means that non-existent users can be detected
3074 at the first server they reach. Set up a file containing a mapping from
3075 the first letter of the user names to the servers where their mailboxes
3076 are held. For example:
3083 Before the normal \%localuser%\ router, place the following router:
3086 driver = manualroute
3088 transport = remote_smtp
3089 route_list = * ${lookup{${substr_0_1:$local_part}}lsearch{/etc/mapfile}}
3092 This router checks for a local account, then looks up the host from the
3093 first character of the local part. If the host is not the local host,
3094 the address is routed to the \%remote_smtp%\ transport, and sent to the
3095 correct host. If the host is the local host, the \self\ option causes
3096 the router to pass the address to the next router, which does a local
3099 The router is skipped for local parts that are not the names of local
3100 users, and so these addresses fail.
3103 Q0426: One of the things I want to set up is for \(anything@onedomain)\ to forward
3104 to \(anything@anotherdomain)\. I tried adding \($local_part@anotherdomain)\ to
3105 my aliases but it did not expand - it sent it to that literal address.
3107 A0426: If you want to do it that way, you can use the \"expand"\ operator on
3108 the lookup used in the data option of the redirect router. For example:
3110 ==> data = ${expand:${lookup{$local_part}lsearch*{/etc/aliases}}}
3112 Another approach is to use a router like this:
3117 data = $local_part@anotherdomain
3119 The value of \data\ can, of course, be more complicated, involving
3120 lookups etc. if you have lots of different cases.
3123 Q0427: How can I have an address looked up in two different alias files, and
3124 delivered to all the addresses that are found?
3126 A0427: Use a router like this:
3130 data = ${lookup{$local_part}lsearch{/etc/aliases1}\
3131 {$value${lookup{$local_part}lsearch{/etc/aliases2}{,$value}}}\
3132 {${lookup{$local_part}lsearch{/etc/aliases2}{$value}fail}}}\
3134 If the first lookup succeeds, the result is its data, followed by the
3135 data from the second lookup, if any, separated by a comma. If the first
3136 lookup fails, the result is the data from the third lookup (which also
3137 looks in the second file), but if this also fails, the entire expansion
3138 is forced to fail, thereby causing the router to decline.
3140 Another approach is to use two routers, with the first re-generating the
3141 original local part when it succeeds. This won't get processed by the
3142 same router again. For example:
3146 data = ${lookup{$local_part}lsearch{/etc/aliases1}{$value,$local_part}}
3149 data = ${lookup{$local_part}lsearch{/etc/aliases2}}
3151 This scales more easily to three or more alias files.
3154 Q0428: I've converted from Sendmail, and I notice that Exim doesn't make use
3155 of the \"owner-"\ entries in my alias file to change the sender address in
3156 outgoing messages to a mailing list.
3158 A0428: If you have an alias file with entries like this:
3160 ==> somelist: a@b, c@d, ...
3161 owner-somelist: postmaster
3163 Sendmail assumes that the second entry specifies a new sender address
3164 for the first. Exim does not make this assumption. However, you can make
3165 it take the same action, by adding
3167 ==> errors_to = owner-$local_part@whatever.domain
3169 to the configuration for your aliasing router. This is fail-safe,
3170 because Exim verifies a new sender address before using it. Thus, the
3171 change of sender address occurs only when the owner entry exists.
3174 Q0429: I would like to deliver mail addressed to a given domain to local
3175 mailboxes, but also to generate messages to the envelope senders.
3177 A0429: You can do this with an ``unseen'' router and an \%autoreply%\ transport,
3178 along the following lines:
3184 domains = <domains you want to do this for>
3185 condition = ${if eq{$sender_address}{}{no}{yes}}
3186 transport = warning_t
3190 Place this router immediately before the normal \%localuser%\ router. The
3191 \unseen\ option means that the address is still passed on to the next
3192 router. The transport is configured like this:
3197 file = /usr/local/mail/warning.txt
3199 from = postmaster@your.domain
3200 to = $sender_address
3202 subject = Re: Your mail to $local_part@$domain
3204 Note the use of the \condition\ option to avoid attempting to send a
3205 message when there is no sender (that is, when the incoming message is a
3206 bounce message). You can of course extend this to include other
3207 conditions. If you want to log the sending of messages, you can add
3209 ==> log = /some/file
3211 to the transport and also make use of the \once\ option if you want to
3212 send only one message to each sender.
3215 Q0430: Whenever Exim tries to route a local address, it gives a permission
3216 denied error for the \(.forward)\ file, like this:
3218 ==> 1998-08-10 16:55:32 0z5y2W-0000B8-00 == xxxx@yyy.zzz <xxxx@yyy.zz>
3219 D=userforward defer (-1): failed to open /home/xxxx/.forward
3220 (userforward router): Permission denied (euid=1234 egid=101)
3222 A0430: Have you remembered to make Exim setuid \/root/\?
3225 Q0431: How do I configure Exim to allow arbitrary extensions in local parts, of
3226 the form \/+extension/\?
3228 A0431: Add this pre-condition to the relevant router:
3230 ==> local_part_suffix = +*
3232 If you want the extensions to be optional, also add the option
3234 ==> local_part_suffix_optional
3236 When the router runs, \$local_part$\ contains the local part with the
3237 extension removed, and the extension (if any) is in \$local_part_suffix$\.
3238 If you have set \check_local_user\, the test is carried out after the
3239 extension is removed.
3242 Q0432: I use NIS for my user data. How can I stop Exim rejecting mail when my
3243 NIS servers are being restarted?
3245 A0432: Exim doesn't know that you are using NIS; it just calls the \^^getpwnam()^^\
3246 function, which is routed by nsswitch. Unfortunately, \^^getpwnam()^^\
3247 was never designed to be routed through NIS, and it returns NULL if the
3248 entry is not found or if the connection to the NIS server fails. This
3249 means that Exim cannot tell the difference between ``no such user'' and
3252 Crutches to help with this problem are \finduser_retries\ in Exim, and
3253 \^nscd^\ on the Unix side, but they are not perfect, and mail can still
3254 be lost. However, Nico Erfurth pointed out that you can create a router
3255 for Exim that tests for the availability of NIS, and force a defer if
3260 data = ${lookup {$local_part} nis {passwd}{}}
3262 This should be placed before any router that makes any use of NIS,
3263 typically at the start of your local routers. How does it work? If
3264 your NIS server is reachable, the lookup will take place, and whether it
3265 succeeds or fails, the result is an empty string. This causes the
3266 router to decline, and the address is passed to the following routers.
3267 If your NIS server is down, the lookup defers, and this causes the
3268 router to defer. A verification of an incoming address gets a temporary
3269 rejection, and a delivery is deferred till later.
3272 Q0433: How can I arrange for a single address to be processed by both
3273 \%redirect%\ and \%accept%\?
3275 A0433: Check out the \unseen\ option.
3278 Q0434: How can I redirect all local parts that are not in my system aliases to
3279 a single address? I tried using an asterisk in the system alias file
3280 with an \"lsearch*"\ lookup, but that sent all messages to the
3283 A0434: If your alias file generates addresses in the local domain, they are
3284 also processed as a potential aliases. For example, suppose this is your
3291 The local part \/caesar/\ is aliased to \/jc/\, but that address is then
3292 reprocessed by the routers. As the address is in the local domain, the
3293 alias file is again consulted, and this time the default matches. In
3294 fact after the second aliasing, \/brutus/\ is also processed again from
3295 the start, and is aliased to itself. However, this happens only once,
3296 because the next time, Exim notices that the aliasing router has already
3297 processed \/brutus/\, so the router is skipped in order to avoid
3300 There are several ways of solving this problem; which one you use
3301 depends on your aliasing data.
3303 (1) If the result of aliasing is always a local user name, that is,
3304 aliasing never generates another alias, you can use the
3305 \redirect_router\ option on the router to specify that processing
3306 the generated addresses must start at the next router. For example:
3308 ==> redirect_router = userforward
3310 assuming that the next router is called \%userforward%\. This
3311 ensures that there is at most one pass through the aliasing router.
3313 (2) If you cannot rely on aliases generating non-aliases, it is often
3314 easier not to use a default alias, but instead to place a router
3315 such as the one below after all the other local routers (for the
3321 data = brutus@$domain
3323 Note that the default aliasing technique works more successfully for
3324 virtual domains (see Q0401) because the generated address for the
3325 default is not usually in the same virtual domain as the incoming
3329 Q0435: My alias file contains fully qualified addresses as keys, and some
3330 wildcard domains in the form @foo.bar. Can Exim handle these?
3332 A0435: You can handle fully qualified addresses with this router:
3334 ==> qualified_aliases:
3336 data = ${lookup{$local_part@$domain}lsearch{/etc/aliases}}
3338 (Add any other options you need for the \%redirect%\ router.) Place this
3339 router either before or after the default aliases router that looks up
3340 the local part only. (Or, if you have no unqualified aliases, replace
3341 the default router.)
3343 To handle wildcards in the form @foo.bar you will need yet another
3344 router. (Wildcards of the form *@foo.bar can be handled by an lsearch*@
3345 lookup.) Something like this:
3347 ==> wildcard_aliases:
3349 data = ${lookup{@$domain}lsearch{/etc/aliases}}
3351 Place this after the routers that handle the more specific aliases.
3357 Q0501: My filter isn't working. How can I test it?
3359 A0501: Use the \-bf-\ option (\-bF-\ for a system filter) to test the basic operation
3360 of your filter. You can request debugging information for filtering only
3361 by adding \"-d-all+filter"\ to the command.
3364 Q0502: What I really need is the ability to obtain the result of a pipe
3365 command so that I can filter externally and redirect internally. Is
3368 A0502: The result of a pipe command is not available to a filter, because Exim
3369 does not run any actual deliveries while filtering. It just sets up
3370 deliveries at this time. They all actually happen later. If you want to
3371 run pipes and examine their results, you need to set up a single
3372 delivery to a delivery agent such as \^procmail^\ which provides this kind
3375 An possible alternative is to use the \"${run"\ expansion item to run an
3376 external command while filtering. In this case, you can make use of some
3377 of the results of the command.
3380 Q0503: I received a message with a ::Subject:: line that contained a non-printing
3381 character (a carriage return). This messed up my filter file. Is there a
3382 way to get round it?
3384 A0503: Instead of \"$h_subject:"\ use \"${escape:$h_subject:}"\
3387 Q0504: I want to search for \"$"\ in the subject line, but I can't seem to get
3390 A0504: Try one of these:
3392 ==> if $h_subject: contains \$ then ...
3393 if $h_subject: contains "\\$" then ...
3396 Q0505: My problem is that Exim replaces \$local_part$\ with an empty string in the
3397 system filtering. What's wrong or what did I miss?
3399 A0505: A message may have many recipients. The system filter is run just once
3400 at the start of a delivery attempt. Consequently, it does not make sense
3401 to set \$local_part$\. Which recipient should it be set to? However, you
3402 can access all the recipients from a system filter via the variable
3403 called \$recipients$\.
3406 Q0506: Using \$recipients$\ in a system filter gives me another problem: how can
3407 I do a string lookup if \$recipients$\ is a list of addresses?
3409 A0506: Check out the section of the filter specification called \*Testing a list of
3410 addresses*\. If that doesn't help, you may have to resort to calling an
3411 embedded Perl interpreter - but that is expensive.
3414 Q0507: What are the main differences between using an Exim filter and using
3417 A0507: Exim filters and \^procmail^\ provide different facilities. Exim filters run
3418 at routing time, before any deliveries are done. A filter is like a
3419 ``\(.forward)\ file with conditions''. One of the benefits is de-duplication.
3420 Another is that if you forward, you are forwarding the original message.
3422 However, this does mean that pipes etc. are not run at filtering time,
3423 nor can you change the headers, because the message may have other
3424 recipients and Exim keeps only a single set of headers.
3426 \^procmail^\ runs at delivery time. This is for one recipient only, and so
3427 it can change headers, run pipes and check the results, etc. However, if
3428 it wants to forward, it has to create a new message containing a copy
3429 of the original message.
3431 It's your choice as to which of these you use. You can of course use
3435 Q0508: How can I allow the use of relative paths in users' filter files when
3436 the directories concerned are not available from the password data?
3438 A0508: You need to be running Exim 4.11 or later. You can then specify a value
3439 for \$home$\ by setting the router_home_directory option on the
3440 \%redirect%\ router.
3442 For earlier releases, there is no way to specify the value of \$home$\
3443 for a \%redirect%\ router; it either comes from the password data as a
3444 result of \check_local_user\, or is unset.
3447 Q0509: How can I set up a filter file to detect and block virus attachments?
3449 A0509: Exim's filter facilities aren't powerful enough to do much more than
3450 very crude testing. Most people that want virus checking are nowadays
3451 using one of the separate scanning programs such as \^exiscan^\ (see
3452 \?http://duncanthrax.net/exiscan/?\). There is some further information
3453 about scanning with Exim via \?http://www.timj.co.uk/linux/exim.php?\.
3456 Q0510: Is it possible to write code for scanning messages in Python?
3458 A0510: \^elspy^\ is a layer of glue code that enables you to write Python code
3459 to scan email messages at SMTP time. \^elspy^\ also includes a small
3460 Python library with common mail-scanning tools, including an interface
3461 to SpamAssassin and a simple but effective virus detector. You can
3462 optain \^elspy^\ from \?http://elspy.sourceforge.net/?\.
3465 Q0511: Whenever my system filter uses a \mail\ command to send a message, I get
3466 the error \*User 0 set for address_reply transport is on the never_users
3467 list*\. What does this mean?
3469 A0511: The system filter runs as \/root/\ in Exim 4, unless you set
3470 \system_filter_user\ to specify otherwise. When you set up a delivery
3471 direct from a system filter (an autoreply is a special kind of
3472 ``delivery'') the transport runs as the same user, unless it has a
3473 \user\ setting of its own. Normally, deliveries are not allowed to run
3474 as \/root/\ as a security precaution; this is implemented by the
3475 \never_users\ option (see Q0039).
3477 The easiest solution is to add this to your configuration:
3479 ==> system_filter_user = exim
3481 The system filter then runs as \/exim/\ instead of \/root/\.
3482 Alternatively, you can arrange for autoreplies from the system filter to
3483 use a special transport of their own, and set the \user\ option on that
3487 Q0512: I'm trying to reference the ::Envelope-To:: header in my filter, but
3488 \$h_envelope-to:$\ is always empty.
3490 A0512: ::Envelope-To:: is added at delivery time, by the transport. Therefore,
3491 the header doesn't exist at filter time. In a user filter, the values
3492 you probably want are in \$original_local_part$\ and
3493 \$original_domain$\. In a system filter, the complete list of all
3494 envelope recipients is in \$recipients$\.
3497 Q0513: I want my system filter to freeze all mails greater than 500K in size,
3498 but to exclude those to a specific domain. However, I don't seem to be
3499 able to use \$domain$\ in a system filter.
3501 A0513: You cannot do this in a system filter, because a single message may have
3502 multiple recipients, some in the special domain, and some not. That is
3503 also the reason why \$domain$\ is not set in a system filter.
3505 If you want to take actions on a per-recipient basis, you have to do it
3506 in a router. However, freezing is not appropriate, because freezing
3507 stops all deliveries. You could, however, delay delivery to all but the
3508 special domains by using something like this:
3510 ==> delay_if_too_big:
3512 domains = !the.special.domain
3513 condition = ${if >{$message_size}{500K}{yes}{no}}
3515 data = :defer: message too big.
3517 However, there isn't an easy way of ``releasing'' such messages at
3521 Q0514: When I try to send to two addresses I get an error in the filter
3522 file \*malformed address: , e@fgh.com may not follow a@bcd.com*\. What
3527 ==> deliver "a@bcd.com, e@fgh.com"
3529 in your filter? If so, that is your problem. You should have
3531 ==> deliver a@bcd.com
3534 Each \deliver\ command expects just one address.
3540 Q0601: What does the error \*Neither the xxx router nor the yyy transport set
3541 a uid for local delivery of...*\ mean?
3543 A0601: Whenever Exim does a local delivery, it runs a process under a specific
3544 user and group id (uid and gid). For deliveries into mailboxes, and to
3545 pipes and files set up by forwarding, it normally picks up the uid/gid
3546 of the receiving user. However, if an address is directed to a pipe or a
3547 file by some other means, such an entry in the system alias file of the
3550 ==> majordomo: |/local/mail/majordomo ...
3552 then Exim has to be told what uid/gid to use for the delivery. This can
3553 be done either on the routerr that handles the address, or on the
3554 transport that actually does the delivery. If a pipe is going to run a
3555 setuid program, then it doesn't matter what uid Exim starts it out with,
3556 and so the most straightforward thing is to put
3560 on either the router or the transport. A setting on the transport
3561 overrides a setting on the router, so if the same transport is being
3562 used with several routers, you should set the user on it only if you
3563 want the same uid to be used in all cases.
3565 In the default configuration, the transports used for file and pipe
3566 deliveries are the ones called \address_file\ and \address_pipe\. You
3567 can specify different transports by setting, for example,
3569 ==> pipe_transport = special_pipe_transport
3571 on the \%system_aliases%\ router. Then you can set up \%special_pipe_transport%\
3573 ==> special_pipe_transport:
3577 which will be used only for pipe deliveries from that one router.
3578 What you put for the ???? is up to you, and depends on the particular
3582 Q0602: Exim keeps crashing with segmentation errors (signal 11 or 139) during
3583 delivery. This seems to happen when it is about to contact a remote
3584 host or when a delivery is deferred.
3586 A0602: This could be a problem with Exim's databases. Try running a delivery
3587 with debugging turned on. If the last line of the debug output is
3588 something like this:
3590 ==> locked /var/spool/exim/db/retry.lockfile
3592 the crash is happening inside the DBM library. Check that your DBM
3593 library is correctly installed. In particular, if you have installed a
3594 second DBM library onto a system that already had one, check that its
3595 version of \(ndbm.h)\ is being seen first. For example, if the new
3596 version is in \(/usr/local/include)\, check that there isn't another
3597 version in \(/usr/include)\. If you are using Berkeley db, you can set
3601 in your \(Local/Makefile)\ to avoid using \(ndbm.h)\ altogether. This is
3602 particularly relevant for version 2 (or later) of Berkeley db, because
3603 no \(ndbm.h)\ file is distributed with it. Another thing you can try is
3606 ==> exim_dumpdb /var/spool/exim retry
3608 to see if it also crashes, or build the \^test_dbfn^\ tool and fiddle
3609 around with it. If both fail, it is most almost certainly a problem with
3610 your DBM library. You could try to update it, or force Exim to use
3611 another library. See the file \(doc/dbm.discuss.txt)\ for hints about
3615 Q0603: How can mails that are being routed through routers that do not set
3616 \check_local_user\ be delivered under the uid of the recipient?
3618 A0603: Q0601 contains background information on this. If you are using, say, an
3619 alias file to direct messages to specific mailboxes, you can use
3620 the \user\ option on either the router or the transport to set the uid.
3621 What you put in the setting depends on how the required uid is to be
3622 found. It could be looked up in a file or computed somehow from the
3623 local part, for example.
3626 Q0604: I want to use MMDF-style mailboxes. How can I get Exim to append the
3627 ctrl-A characters that separate indvidual emails?
3629 A0604: Set the \message_suffix\ option in the \%appendfile%\ transport. In fact,
3630 for MMDF mailboxes you need a prefix as well as a suffix to get it
3631 working right, so your transport should contain these settings:
3633 ==> message_prefix = "\1\1\1\1\n"
3634 message_suffix = "\1\1\1\1\n"
3636 Also, you need to change the \check_string\ and \escape_string\ settings so
3637 that the escaping happens for lines in the message that happen to begin
3638 with the MMDF prefix or suffix string, rather than ``From'' (the default):
3640 ==> check_string = "\1\1\1\1\n"
3641 escape_string = "\1\1\1\1 \n"
3643 Adding a space to the line is sufficient to prevent it being taken as a
3647 Q0605: If a user's mailbox is over quota, is there a way for me to set it up so
3648 that the mail bounces to the sender and is not stored in the mail queue?
3650 A0605: In the retry section of the configuration, put
3652 ==> *@your.dom.ain quota
3654 That is, provide no retry timings for over quota errors. They will then
3655 bounce immediately. Alternatively, you can set up retries for a short
3656 time only, or use something like this:
3658 ==> *@your.dom.ain quota_7d
3659 *@your.dom.ain quota F,2h,15m; F,3d,1h
3661 which bounces immediately if the user's mailbox hasn't been read for 7
3662 days, but otherwise tries for up to 3 days after the first quota
3666 Q0606: I'm using tmail to do local deliveries, but when I turned on the
3667 \use_crlf\ option on the \%pipe%\ transport (tmail prefers \"@\r@\n"\
3668 terminations) message bodies started to vanish.
3670 A0606: You need to unset the \mesage_prefix\ option, or change it so that its
3671 default \"@\n"\ terminator becomes \"@\r@\n"\. For example, the
3674 ==> local_delivery_mbx:
3676 command = /usr/local/bin/tmail $local_part
3678 current_directory = /
3682 The reason for this is as follows: tmail uses the line terminator on
3683 the first line it sees to determine whether lines are terminated by
3684 \"@\r@\n"\ or \"@\n"\. If the latter, it moans to stderr and changes subsequent
3685 \"@\n"\ terminators to \"@\r@\n"\. The default setting of the \message_prefix\
3686 option is \"From ...@\n"\, and this is unaffected by the \use_crlf\ option.
3687 If you don't change this, tmail sees the first line terminated by
3688 \"@\n"\ and prepends \"@\r"\ to the \"@\n"\ terminator on all subsequent
3689 lines. However, if \use_crlf\ is set, Exim makes all other lines
3690 \"@\r@\n"\ terminated, leading to doubled \"@\r@\r@\n"\ lines and
3691 corrupt mbx mailboxes.
3694 Q0607: When I activate ``return receipt'' for example in Netscape Mailbox
3695 sending options, then I get an error message from Exim... something
3696 like \*not supported*\. Can I activate delivery confirmations?
3698 A0607: Exim does not support any kind of delivery notification.
3700 (1) You can configure it to recognize headers such as
3701 \Return-receipt-to:\ if you wish.
3703 (2) Some people want MSN (message status notification). Such services
3704 are implemented in MUAs, and don't impact on the MTA at all.
3706 (3) I investigated the RFCs which describe the DSN (delivery status
3707 notification) system. However, I was unable to specify any sensible way
3708 of actually doing anything with the data. There were comments on the
3709 mailing list at the time; many people, including me, conclude that DSN
3710 is in practice unworkable. The killer problem is with forwarding and
3711 aliasing. Do you propagate the DSN data with the generated addresses?
3712 Do you send back a ``reached end of the DSN world'' or ``expanded'' message?
3713 Do you do this differently for different kinds of aliasing/forwarding?
3714 For a user who has a \(.forward)\ file with a single address in, this
3715 might seem easy - just propagate the data. But what if there are several
3716 forwardings? If you propagate the DSN data, the sender may get back
3717 several DSN messages - and should the sender really know about the
3718 detail of the receiver's forwarding arrangements? There isn't really
3719 any way to distinguish between a \(.forward)\ file that is forwarding
3720 and one that is a mini mailing list. And so on, and so on. There are so
3721 many questions that don't have obvious answers.
3724 Q0608: What does the message \*retry time not reached [for any host]*\ on the log
3725 mean? Why won't Exim try to deliver the message?
3727 A0608: That is not an error. It means exactly what it says. A previous attempt
3728 to deliver to that address failed with a temporary error, and Exim
3729 computed the earliest time at which to try again. This can apply to
3730 local as well as to remote deliveries. For remote deliveries, each host
3731 (if there are several) has its own retry time.
3733 If you are running on a dial-up host, the rest of this answer probably
3734 does not apply to you. Go and read Q1404 instead. If your host is
3735 permanently online, read on...
3737 Some MTAs have a retrying schedule for each message. Exim does not work
3738 like this. Retry timing is normally host-based for remote deliveries and
3739 address-based for local deliveries. (There are some exceptions for certain
3740 kinds of remote failure - see \*Errors in outgoing SMTP*\ in the manual.)
3742 If a new message arrives for a failing address and the retry time has
3743 not yet arrived, Exim will log \*retry time not reached*\ and leave the
3744 message on the queue, without attempting delivery. Similarly, if a queue
3745 runner notices the message before the time to retry has arrived, it
3746 writes the same log entry. When the retry time has past, Exim attempts
3747 delivery at the next queue run. If you want to know when that will be,
3748 run the exinext utility on the address, for example:
3750 ==> exinext user@some.domain
3752 You can suppress these messages on the log by including \"-retry_defer"\
3753 in the setting of \log_selector\. You can force a delivery attempt on a
3754 specific message (overriding the retry time) by means of the -M option:
3756 ==> exim -M 10hCET-0000Bf-00
3758 If you want to do this for the entire queue, use the \-qf-\ option.
3761 Q0609: Exim seems to be sending the same message twice, according to the log,
3762 although there is a difference in capitalization of the local part of
3765 A0609: That is correct. The RFCs are explicit in stating that capitalization
3766 matters for local parts. For remote domains, Exim is not entitled to
3767 assume case independence of local parts. I know, it is utterly silly,
3768 and it causes a lot of grief, but that's what the rules say. Here is a
3769 quote from RFC 2821:
3771 ... a command verb, an argument value other than a mailbox local-part,
3772 and free form text MAY be encoded in upper case, lower case, or any
3773 mixture of upper and lower case with no impact on its meaning. This
3774 is NOT true of a mailbox local-part. The local-part of a mailbox
3775 MUST BE treated as case sensitive. Therefore, SMTP implementations
3776 MUST take care to preserve the case of mailbox local-parts. Mailbox
3777 domains are not case sensitive. In particular, for some hosts the
3778 user "smith" is different from the user "Smith". However, exploiting
3779 the case sensitivity of mailbox local-parts impedes interoperability
3783 Q0610: How can I force the next retry time for a host to be now?
3785 A0610: You can change the retry time with the \^exim_fixdb^\ utility, but its
3786 interface is very clumsy. If you have a message for the host on the
3787 queue, the simplest thing to do is to force a delivery with the \-M-\
3788 command line option. If delivery succeeds, the retry data will get
3789 cleared. If the host is past the cutoff time, so that messages are
3790 bouncing immediately without trying a delivery, you can use \-odq-\ to
3791 put a message on the queue without a delivery attempt, and then use
3795 Q0611: I set up \"|/bin/grep Subject|/usr/bin/smbclient -M <netbiosname>"\ as an
3796 alias but it doesn't work.
3798 A0611: That is a shell command line. Exim does not run pipe commands under a
3799 shell by default (for added security - and it saves a process). You
3802 ==> "|/bin/sh -c '/bin/grep Subject|/usr/bin/smbclient -M <netbiosname>'"
3805 Q0612: Why does the \%pipe%\ transport add a line starting with \">From"\ to
3808 A0612: Actually, it adds a line starting with \"From"\ followed by a space.
3809 This is commonly referred to as the \"From_"\ line, to emphasize the
3810 fact that \"From"\ is followed by a space and not a colon. This is a
3811 pseudo-header line that contains the envelope sender address and the
3812 time of delivery. It originated as a separator line in Berkeley format
3813 mailboxes, but is also used in other contexts. (And yes, it is often
3814 confused with the ::From:: header line, and this causes a lot of grief.
3815 The use of \"From_"\ was one of the really bad email design decisions.)
3817 Exim's \%pipe%\ transport adds this pseudo-header line by default
3818 because \(/usr/ucb/vacation)\ needs it, and that is one of the the most
3819 common uses of piping. The \^procmail^\ local delivery agent also makes
3820 use of the \"From_"\ line. If you do not want it, change the setting of
3821 \message_prefix\ on the \%pipe%\ transport. For example, to remove the
3822 line altogether, use
3824 ==> message_prefix =
3826 If you are not piping to \(/usr/ucb/vacation)\ or \^procmail^\, it is
3827 likely that you do not need a \"From_"\ line, and indeed it may cause
3828 problems if it is present.
3830 One user reported that this line gave trouble when a pipe was used to
3831 send messages to Courier's \^deliverquota^\ program. The line was
3832 retained with the message, and caused problems for MS Exchange 2000 when
3833 retrieving messages with its built-in POP collector. Specifically, it
3834 caused Exchange to not be able to recognise message attachments.
3837 Q0613: I have set \fallback_hosts\ on my \%smtp%\ transport, but after the error
3838 \*sem@chat.ru cannot be resolved at this time*\ Exim isn't using them.
3840 A0613: \fallback_hosts\ works only if an attempt at delivery to the original
3841 host(s) fails. In this case, Exim couldn't even resolve the domain
3842 \(chat.ru)\ to discover what the original hosts were, so it never got as far
3843 as the transport. However, see Q0315 for a possible solution.
3846 Q0614: After the holidays my ISP has always hundreds of e-mails waiting for me.
3847 These are forced down Exim's throat in one go. Exim spawns a lot of
3848 kids, but is there some limit to the number of processes it creates?
3850 A0614: Unless you have changed \smtp_accept_queue_per_connection\ it should
3851 spawn only that many processes per connection (default 10). Your ISP
3852 may be making many connections, of course. That is limited by
3856 Q0615: When a message in the queue got to 12h old, Exim wrote \*retry timeout
3857 exceeded*\ and removed all messages in the queue to this host - even
3858 recent messages. How I can avoid this behaviour? I only want to remove
3859 messages that have exceeded the maximum retry time.
3861 A0615: Exim's retrying is host-based rather than message-based. The philosophy
3862 is that if a host has been down for a very long time, there is no point
3863 in keeping messages hanging around. However, you might like to check
3864 out \delay_after_cutoff\ in the \%smtp%\ transport. It doesn't do what you
3865 want, but it might help.
3868 Q0616: Can Exim add a ::Content-Length:: header to messages it delivers?
3870 A0616: You could include something like
3872 ==> headers_remove = "content-length"
3873 headers_add = "Content-Length: $message_body_size"
3875 to the \%appendfile%\ transport. However, the use of ::Content-Length:: can
3876 cause several problems, and is not recommended unless you really know
3877 what you are doing. There is a discussion of the problems in
3878 \?http://home.netscape.com/eng/mozilla/2.0/relnotes/demo/content-length.html?\.
3881 Q0617: Exim seems to be trying to deliver a message every 10 minutes, though
3882 the retry rules specify longer times after a while, because it is
3883 writing a log entry every time, like this:
3885 ==> 1999-08-26 14:51:19 11IVsE-000MuP-00 == example@example.com T=smtp defer
3886 (-34): some host address lookups failed and retry time not reached for
3887 other hosts or connection limit reached
3889 A0617: It is looking at the message every 10 minutes, but it isn't actually
3890 trying to deliver. It's looking up \(example.com)\ in the DNS and finding
3893 ==> example.com. MX 10 example-com.isp.example.com.
3894 example.com. MX 0 mail.example.com.
3895 mail.example.com. A 202.77.183.45
3896 A lookup for example-com.isp.example.com. yielded NXDOMAIN
3898 The last line means that there is no address (A) record in the DNS for
3899 \(example-com.isp.example.com)\. That accounts for \*some host address
3900 lookups failed*\, but the retry time for \(mail.example.com)\ hasn't been
3901 reached, which accounts for \*retry time not reached for other hosts*\.
3904 Q0618: I am trying to set exim up to have a automatic failover if it sees that
3905 the system that it is sending all mail to is down.
3907 A0618: Add to the \%remote_smtp%\ transport the following:
3909 ==> fallback_hosts = failover.server.name(s)
3911 If there are several names, they must be separated by colons.
3914 Q0619: I can't get Exim to deliver over NFS. I get the error \*fcntl() failed:
3915 No locks available*\, though the lock daemon is running on the NFS server
3916 and other hosts are able to access it.
3918 A0619: Check that you have \(lockd)\ running on the NFS client. This is not
3919 always running by default on some systems (Red Hat is believed to be one
3923 Q0620: Why does Exim bounce messages without even attempting delivery, giving
3924 the error \*retry time not reached for any host after a long failure
3927 A0620: This message means that all hosts to which the message could be sent
3928 have been failing for so long that the end of the retry period
3929 (typically 4 or 5 days) has been reached. In this situation, Exim still
3930 computes a next time to retry, but any messages that arrive in the
3931 meantime are bounced straight away. You can alter this behaviour by
3932 unsetting the \delay_after_cutoff\ option on the smtp transport. Then Exim
3933 will try most messages for those hosts once before giving up.
3936 Q0621: My \(.forward)\ file is \"|/usr/bin/procmail -f-"\ and mail gets delivered,
3937 but there was a bounce to the sender, sending him the output of procmail.
3938 How can I prevent this?
3940 A0621: Exim's default configuration is set up like this:
3946 The \return_output\ option requests that any output that the pipe
3947 produces be returned to the sender. That is the safest default. If you
3948 don't want this, you can either remove the option altogether, or change
3949 it to \return_fail_output\, to return output only if the command fails.
3950 Note that this will affect all pipes that users run, not just your
3951 procmail one. It might be better to arrange for procmail not to produce
3952 any output when it succeeds.
3955 Q0622: Can I write an ordinary file when I run a perl script as a transport
3956 filter for the \%remote_smtp%\ and \%address_pipe%\ transports?
3958 A0622: Yes, provided the file is writeable by the uid under which the transport
3959 runs (the Exim user in the case of the remote transport). However, if two
3960 messages are being delivered at once, their data will get mixed up in
3961 the file unless you implement your own locking scheme. If all you want
3962 to do is to take a copy of the message, another approach that avoids
3963 the locking problem is to use a system filter to set up an ``unseen''
3964 delivery to a file. If you only want the message's headers, you can
3965 set \message_filter_file_transport\ to point to a special \%appendfile%\
3966 transport that has \headers_only\ set.
3969 Q0623: My \(/var/spool/mail)\ has grown drastically. Is there any possibility of
3970 using two directories?
3972 A0623: You can use an expansion string to split mailboxes between two
3973 directories. For example,
3975 ==> file = /var/spool/mail${nhash_2:$local_part}/$local_part
3977 which does a hash on the local part, producing either 0 or 1, thereby
3978 using \(mail0) or \(mail1)\. But remember, the MUAs that read these mailboxes
3979 also have to know where they are.
3982 Q0624: Sendmail has a program called \^smrsh^\ that restricts what binaries
3983 can be run from sendmail aliases. Is there something like this in Exim ?
3985 A0624: Check out the \allow_commands\ option in the \%pipe%\ transport.
3988 Q0625: I wish to have large emails go out one at a time.
3990 A0625: One possibility is to set up a router that defers all large messages,
3991 except in queue runs. Since queue runners deliver just one
3992 message at a time, if you limited the number of simultaneous queue
3993 runners to 1, you would get the effect you wanted. A suitable router
3996 ==> defer_if_large_unless_queue_run:
3998 condition = ${if or{{queue_running}{<{$message_size}{200K}}}{no}{yes}}
4000 data = :defer: too large for immediate delivery
4003 Of course, this would always delay any large message until the next
4004 queue runner, but if you run them fairly regularly, this shouldn't be a
4005 huge problem, and may even be desirable. Note the use of \no_verify\ to
4006 ensure that this router is not used when Exim is verifying addresses.
4009 Q0626: Exim can route local parts independent of their case, but the Cyrus LMTP
4010 daemon requires the correct case. How can I fix this?
4012 A0626: You need to rewrite the local part to the correct case before running
4013 the router that routes to Cyrus. For example, if you require all lower
4014 case, and your router is called \local_user\, put this router in front
4017 ==> lowercase_local:
4019 redirect_router = local_user
4020 domains = +local_domains
4021 data = ${lc:$local_part}@$domain
4023 The setting of \redirect_router\ causes processing of the rewritten
4024 address to start at the next router, instead of the first router. See
4025 also Q0630 and Q0414, and see C045 for a more complete Cyrus
4029 Q0627: Is there a command I can send to Exim to retry all queued messages
4030 regardless of their retry schedule?
4032 A0627: The \-qff-\ option starts a queue runner that forces a delivery attempt
4033 for all messages, including frozen ones. If you use \-qf-\, frozen
4034 messages are skipped.
4037 Q0628: I have the default retry rule, which I thought meant that Exim should
4038 keep trying for four days, but it seems to be bouncing some messages
4041 A0628: See Q0615 and Q0620.
4044 Q0629: I'm having trouble with quotas and Courier, because Exim is not handling
4047 A0629: You must be using an old version of Exim; it has supported maildirsize
4048 files since release 4.30.
4051 Q0630: How can I configure Exim to deliver to a Cyrus message store?
4053 A0630: (1) The reference manual contains an example that uses pipe delivery.
4055 (2) Here is a transport that uses LMTP delivery, assuming that
4056 \$local_part$\ contains the username:
4061 socket = /var/cyrus/socket/lmtp
4063 (3) This is a transport that delivers direct to a non-inbox mailbox:
4072 command = "/usr/cyrus/bin/deliver -a $local_part \
4073 -m <mailbox-name> $local_part"
4075 This delivers to the Cyrus mailbox \"user.$local_part.<mailbox-name>"\.
4076 Using \"user = $local_part"\ and \"-a $local_part"\ makes it work
4077 without needing an explicit `p' ACL set for `anyone' on the mailbox.
4080 Q0631: I would like to choose a retry rule based on on the sender rather than
4081 the recipient address. Is this possible?
4083 A0631: Yes. In release 4.43 and later releases, you can do this directly by
4084 adding a third item to a retry rule of the form "senders=<address
4085 list>". The retry timings themselves then become the fourth item. For
4088 ==> * * senders=: F,1h,30m
4090 would match all bounce messages. If the address list contains white
4091 space, it must be enclosed in quotes. For example:
4093 ==> a.domain timeout senders="x@b.dom : y@c.dom" G,8h,10m,1.5
4095 If you are using an earlier release of Exim, you can still achieve the
4096 effect, but in a more complicated way. The address part of a retry rule
4097 is matched as a single-item address list. Such lists are always
4098 expanded, so you can use something like this:
4100 ==> "${if eq{$sender_address}{xxx}{*@*}{no@no}}" quota F,1h,10m; ...
4102 If the sender address is ``xxx'', the pattern expands to ``*@*'', which
4103 matches all recipient addresses; if you want to, you can make this a
4104 more restrictive pattern. If the sender address is not ``xxx'', the
4105 pattern expands to ``no@no'', which is assumed to be a recipient address
4106 that can never match, so the retry rule is skipped.
4109 Q0632: What does the error \*User 1 set for local_mbx_delivery transport is on
4110 the never_users list*\ mean?
4112 A0632: You have configured the \%local_mbx_delivery%\ to run as the user whose
4113 id (uid) is 1. However, this user is on the list defined by the
4114 \never_users\ runtime option, or the \\FIXED_NEVER_USERS\\ compile-time
4115 option. These are ``safety catch'' lists; Exim refuses to deliver to any
4116 user that is on them. The most common use of \never_users\ is to avoid
4117 doing any deliveries as \/root/\, but it can contain other uids.
4120 Q0633: Why is \$domain$\ not set in the \%smtp%\ transport?
4122 A0633: The \%smtp%\ transport can handle several recipient addresses at once.
4123 This happens by default if the host lists for the addresses are
4124 identical. A single copy of the message is sent, using multiple \\RCPT\\
4125 commands to transmit multiple envelope recipients. The \$domain$\
4126 variable is set in the \%smtp%\ transport only if all the recipient
4127 addresses have the same domain. You must have a case where several
4128 addresses with different domains resolve to the same set of hosts.
4130 If you want to restrict the transport so that it handles only a single
4131 domain at once (but still possibly with more than one recipient), set
4133 ==> multi_domain = false
4135 If you want to restrict the transport so that it handles only a single
4136 address at once, set
4141 Q0634: How can I stop a local transport from trying to access the user's home
4142 directory, even when the delivery is to a file that is elsewhere?
4144 A0634: See answer (2) for Q0423.
4147 Q0635: The log message \*error ignored*\ appears after some delivery failures.
4150 A0635: This message is written when Exim fails to deliver a bounce message whose
4151 age is greater than \ignore_bounce_errors_after\. It indicates that the
4152 failing bounce message has been discarded.
4154 The same message is written after failed deliveries when a filter file
4155 uses the \noerror\ feature when setting up a delivery, or if a router
4160 Both of these specify that delivery failures are to be discarded.
4166 Q0701: How do I block unwanted messages from outside my host?
4168 A0701: Exim uses Access Control Lists (ACLs) for controlling incoming mail from
4169 other hosts. A whole chapter in the reference manual is devoted to
4170 describing how they work. A wide variety of conditions can be imposed on
4173 The default Exim run time configuration contains an example of an ACL
4174 which blocks all relaying, and messages whose senders cannot be
4175 verified. This example is heavily commented and worth studying.
4178 Q0702: I don't want to block spam entirely; how can I inspect each message
4179 before deciding whether or not to deliver it?
4181 A0702: Wherever possible, inspection and rejection is best done automatically
4182 in an ACL, that is, before the message is accepted. If you want to
4183 verify manually each message that is classified as spam by an automatic
4184 check, you can arrange for a system filter to freeze such messages after
4185 they have been accepted.
4187 If, after inspection, you decide not to deliver the message, it is
4188 safest to discard it, using the \-Mrm-\ option. Use of the \-Mg-\ option
4189 to force a bounce carries the risk of ``collateral spam'' if the sender
4190 address is faked (as it usually is in spam).
4193 Q0703: How can I test that my spam blocks are working?
4195 A0703: The \-bh-\ option allows you to run a testing SMTP session as if from a
4196 given IP address. For example,
4198 ==> exim -bh 192.168.178.39
4200 In addition to the normal SMTP replies, it outputs commentary about
4201 which tests have succeeded or failed. If you are not interested in the
4202 details, but just want to know if a particular sender at a particular IP
4203 address is able to mail to a particular recipient, you can use the
4204 \exim_checkaccess\ utility, which provides a ``packaged'' version of
4205 \-bh-\. You call it like this:
4207 ==> exim_checkaccess 192.168.53.23 recip@my.domain -f sender@some.domain
4209 If you don't give a sender, \"<>"\ is used (that it, it acts like a
4213 Q0704: How can I test that Exim is correctly configured to use a DNS black list
4214 such as the Realtime Blackhole List (RBL)?
4216 A0704: The \-bh-\ option allows you to run a testing SMTP session as if from a
4217 given address. The \^exim_checkaccess^\ utility provides a more packaged
4218 version of this facility. You need to know a blocked IP address with
4219 which to test. Such a testing address is kindly provided by Russell
4222 ==> linux.crynwr.com [192.203.178.39]
4224 You can also send mail to \(nelson@linux.crynwr.com)\ from the server
4225 whose RBL block you are testing. The robot that receives that email
4226 will attempt to send a piece of test email in reply. If your RBL block
4227 didn't work, you get a message to that effect. Regardless of whether the
4228 RBL block succeeds or not, it emails you the results of the SMTP
4229 conversation from a host that is not on the RBL, so you can see how your
4230 server looks from the view of someone on the RBL.
4233 Q0705: How can I use tcpwrappers in conjunction with Exim?
4235 A0705: Exim's own control facilities can do all that tcpwrappers can do.
4236 However, if you are already using tcpwrappers for other things it might
4237 be convenient to include Exim controls in the same place.
4239 First of all, ensure that Exim is built to call the tcpwrappers library,
4240 by including \\USE_TCPWRAPPERS=yes\\ in \(Local/Makefile)\. You also need to
4241 ensure that the header file \(tcpd.h)\ is available at compile time, and the
4242 \(libwrap.a)\ library is available at link time, typically by including it in
4243 \\EXTRALIBS\\. You may need to copy these two files from the tcpwrappers
4244 build directory to, for example, \(/usr/local/include)\ and \(/usr/local/lib)\,
4245 respectively. Then you could reference them by
4247 ==> CFLAGS=-I/usr/local/include
4248 EXTRALIBS=-L/usr/local/lib -lwrap
4250 in \(Local/Makefile)\. There are two ways to make use of the functionality,
4251 depending on how you have tcpwrappers set up. If you have it set up to
4252 use only one file, you ought to have something like:
4254 ==> /etc/hosts.allow:
4256 ==> exim : <client_list> : <allow_or_deny>
4260 ==> exim : LOCAL 192.168.0. .friendly.domain special.host : ALLOW
4263 This allows connections from local hosts (chiefly //localhost//), from
4264 the subnet 192.168.0.0/24, from all hosts in \(*.friendly.domain)\, and
4265 from a specific host called \(special.host)\. All other connections are
4266 denied. If you have tcpwrappers set up to use two files, use the
4269 ==> /etc/hosts.allow:
4271 ==> exim : <client_list>
4273 ==> /etc/hosts.deny:
4275 ==> exim : <client_list>
4277 Read the \^hosts_access^\ man page for more ways of specifying clients,
4278 including ports, etc., and on logging connections.
4281 Q0706: How can I get POP-auth-before-relay (aka POP-before-SMTP) support in
4284 A0706: A cleaner way of authentication is to use the SMTP AUTH facility, which
4285 does not require a prior use of POP. However, it is possible to do what
4288 Exim 4 supports the ``whoson'' (\?http://whoson.sourceforge.net?\)
4289 facility for doing this. If you set this up, you can do the check in an
4290 Exim ACL by a statement like this:
4292 ==> require condition = \
4293 ${lookup whoson {$sender_host_address}{yes}{no}}
4295 Otherwise you need to arrange for a list of permitted IP addresses to be
4296 maintained in a file or database, and use this in a \hosts\ condition in
4297 an ACL statement. An Exim user has published this recipe:
4299 \#\#\#\#\?http://www.zeiss.cx/memo/computer/linux/email/exim-s-a-p.html?\
4301 Another Exim user submitted the following idea:
4303 Use a script to grab authenticated IP addresses from the log files of
4304 the POP3 and IMAP4 daemons. These are used to create files in the
4305 directory tree \(/var/db/popb4smtp)\. The existence of a file represents a
4306 valid ``popped recently token'' for the IP address used as the filename.
4308 Another script periodically removes stale files from the tree (after two
4309 hours). There's a small race condition here; it's possible for a file
4310 to be deleted just after it has been updated by the script that watches
4311 the logs. For low-volume servers, the odds of hitting this window are
4314 A POPB4SMTP_CLIENT macro in the Exim configure file provides a reusable
4315 ``has this sender popped recently?'' query:
4317 ==> POPB4SMTP_SUBDIR = /var/db/popb4smtp/${substr_-1_1:$sender_host_address}
4318 POPB4SMTP_CLIENT = ${if exists {POPB4SMTP_SUBDIR/$sender_host_address} \
4319 {$sender_host_address} {0} }
4321 Now you can use it just about anywhere, including in your ACLs. Simple
4324 ==> hostlist relay_hosts = 127.0.0.1/32 : ... : POPB4SMTP_CLIENT
4325 host_lookup = !127.0.0.1/32 : ... : !POPB4SMTP_CLIENT
4326 rfc1413_hosts = !127.0.0.1/32 : ... : !POPB4SMTP_CLIENT
4328 The two scripts (and a FreeBSD startup script for them) are available
4331 \#\#\#\#\?http://people.FreeBSD.org/~sheldonh/popb4smtp-nodb.tar.gz?\
4334 Q0707: I have one or two cases where my host correctly rejects messages, but
4335 the remote host is quite persistent, and keeps trying over and over.
4337 A0707: It is an unfortunate fact that a number of SMTP clients, in violation of
4338 the SMTP RFC, do not treat a permanent error code that is given after
4339 the DATA portion of the transaction as a permanent error. Consequently
4340 they keep resending the message, and the worst offenders do so at very
4343 The only way to stop such behaviour is to blacklist the IP address, or
4344 the envelope sender, or both, in such a way that future messages get
4345 rejected at RCPT time instead of at DATA time. You could also complain
4346 to the remote host's administrators.
4349 Q0708: How can I run customized verification checks on incoming addresses?
4351 A0708: There are a number of possibilities:
4353 (1) If you can implement your checks in Perl, you can use Exim's
4354 facility for running an embedded Perl interpreter. For example, if you
4355 want to run special checks on local addresses, you could use ACL
4356 an statement like this:
4358 ==> require domains = my.local.domain
4359 condition = ${perl{verify}{$local_part}}
4361 The result of the Perl function should be ``yes'' or ``no''.
4363 (2) You could also run an external program in a similar way, by a
4366 ==> require domains = my.local.domain
4367 condition = ${run{/my/verifier $local_part}}
4369 This requires the use of another process, so could prove more expensive
4372 (3) If you are prepared to write C code, read the chapter in the manual
4373 entitled \*Adding a local scan function to Exim*\.
4376 Q0709: Does Exim apply RBL checks to error messages, those with an envelope
4379 A0709: This depends on the ACL configuration. You can test for bounce messages
4380 (by looking for an empty sender address) and thereby exclude them from
4381 RBL checking if you want. This ACL statement does that:
4383 ==> deny senders = ! :
4384 dnslist = blackholes.mail-abuse.org
4386 However, some spam does come with an empty sender address, so this may
4390 Q0710: I want to reject certain sender-recipient combinations, with a specific
4391 message for each such combination.
4393 A0710: Set up a file (or database) containing the messages, keyed by the
4394 combination, for example:
4396 ==> sender1@sdomain1=>recipient1@rdomain1: blocked because...
4397 sender2@sdomain2=>recipient2@rdomain2: blocked because...
4399 If you have lots of recipients for the same sender, it might be easier
4400 to generate this file from more convenient data. In your ACL that is run
4401 for each RCPT command, you can then put:
4403 ==> deny message = ${lookup{$sender_address=>$local_part@$domain}\
4404 lsearch{/that/file}}
4405 condition = ${lookup{$sender_address=>$local_part@$domain}\
4406 lsearch{/that/file}}{yes}{no}}
4408 The condition is tested first. If the lookup succeeds, the condition
4409 succeeds so access is denied. The message is then expanded, but the
4410 lookup won't be repeated, because Exim will have cached the previous
4413 This approach blocks only incoming SMTP messages. If you need to do
4414 similar blocks for messages that do not arrive over SMTP, you have to
4415 set up a suitable \%redirect%\ router with a \:fail:\ setting.
4418 Q0711: Will Exim allow me to create a file of regexs and match incoming
4419 external email to the list - and if a match is found file the offending
4420 message into a special location? Also is it possible to make Exim only
4421 filter parts of an incoming email - e.g. ignore large MIME attachments
4422 for example and only process text/plain?
4424 A0711: You can do some of this in a system filter. For example:
4426 ==> if $message_body matches <...some complicated regex...> or
4427 $message_body matches <...some other regex...> or
4428 $header_from: matches <...regex...> or
4431 save /some/special/file
4434 or instead of \"save"\ you could have \"deliver"\ (to some address) or
4435 \"pipe"\ (to some script).
4437 There isn't any mechanism for ignoring attachments, but \$message_body$\
4438 only looks at the first n bytes of the body, where n defaults to 500 but
4441 A more expensive alternative would be to run a Perl subroutine using the
4442 embedded Perl mechanism. If you passed over the message id, the Perl
4443 code could read the message files on the spool and implement any
4444 algorithm it liked for deciding what should be done.
4447 Q0712: I've hacked sendmail to make an ioctl call at the time of the SMTP RCPT
4448 command, to check if a user has exceeded their email quota. If they have
4449 I issue a temporary failure and a message - can I do this with Exim?
4451 A0712: If you can make this happen in Perl you can use the embedded Perl
4452 facility, and use it from a \condition\ condition in an ACL statement.
4453 You can also use the expansion facility to run an external program, but
4454 this uses more resources because it uses another process.
4457 Q0713: I'd like to pass all messages through a virus-scanning system before
4458 delivery. Can Exim do this?
4460 A0713: One way of achieving this is to deliver all messages via a pipe to a
4461 checking program that resubmits them for delivery in some private way
4462 that can be checked (e.g. on a specific SMTP port, or IP address). One
4463 possibility is to use the `received protocol` field that can be set
4464 for locally submitted mail via the \-oMr-\ command line option. This
4465 router sends all messages that are not from the local host and whose
4466 received protocol is not \"scanned-ok"\ to the \%virus_scan%\ transport:
4470 transport = virus_scan
4471 condition = ${if or {{eq {$received_protocol}{scanned-ok}} \
4472 {eq {$sender_host_address}{127.0.0.1}}}\
4475 One problem is that this approach, by default, scans the message for
4476 each recipient, not just once per message. However, you can set the
4477 \batch_max\ option on the transport to allow it to send a single copy
4478 for multiple recipients.
4480 The virus_scan transport should be set up to pipe the message to a
4481 suitable checking program or script which runs as a trusted user. This
4482 can then re-submit the message to Exim, using \-oMr-\ to set the received
4483 protocol to \"scanned-ok"\. It is probably easiest to use the Batch SMTP
4484 (BSMTP) facilities for passing the sender address and the recipient
4485 addresses to the checker and then back to Exim (using the \-bS-\
4486 command line option). \**Warning:**\ If you forget to make the
4487 resubmitting process run as a trusted user, the sender address will be
4488 incorrect and what is worse, the received protocol does not get set, and
4489 you are likely to generate a loop.
4492 Q0714: Is there a way to configure Exim to reject mail to a certain local host?
4494 A0714: No, only to certain domains. To reject at SMTP time, you can put a line
4495 like this in your ACL:
4497 ==> deny message = this domain is deliberately rejected
4498 domains = a.certain.domain
4500 To fail addresses in messages that do not arrive over SMTP, you can set
4501 up a router like this:
4503 ==> reject_a_certain_domain:
4505 domains = a.certain.domain
4507 data = :fail: this domain is deliberately rejected
4510 Q0715: How can I get Exim to remove attachments from messages?
4512 A0715: Exim does not contain facilities for modifying messages. You must use
4513 an external program if you want to do this. You can route messages that
4514 have a ::Content-type:: header line via a pipe to a command that does
4515 the job and then re-submits the message to Exim. Alternatively, you
4516 could use a transport filter to do this job.
4519 Q0716: How can I arrange for each user to have a file listing the only sender
4520 addresses from which she will accept mail? I want to do this so my
4521 family members don't get any spam (or other inappropriate mail).
4523 A0716: Let's assume each user has a file called \(.acceptlist)\ in the home
4524 directory. You can put in your ACL a line like this:
4526 ==> require senders = /home/$local_part/.acceptlist
4528 This will reject RCPT commands when the sender is not in the accept
4529 list for the recipient. (Replace \(/home/$local_part)\ with whatever
4530 the correct path to your user's home directories is.)
4532 One problem with this is that it will block bounce messages, which have
4533 empty senders. You can get round this, by changing the line to this:
4535 ==> require senders = : /home/$local_part/.acceptlist
4537 However, this will, of course, let in spam that has a null sender.
4540 Q0717: When using Nessus on a system that runs Exim, a number of security
4541 issues are raised. Nessus complains that Exim answers to EXPN and/or
4542 VRFY; sometimes it even complains that Exim allows relaying.
4544 A0717: Exim supports EXPN and VRFY only if you permit it to do so in the ACLs
4545 defined by \acl_smtp_expn\ and \acl_smtp_vrfy\, respectively. Otherwise,
4548 ==> 550 Administrative prohibition
4549 252 Administrative prohibition
4551 Maybe the use of 252 is the ``problem''. It is recommended that this be
4552 done (by those that discuss these things) because there are stupid
4553 clients that attempt VRFY before sending a message.
4556 Q0718: Could anyone points me to right rules to prevent sending/receiving
4557 messages to/for domains which have one MX to localhost or only have
4563 Q0719: I would like to have a per-user limit for the maximum size of messages
4566 A0719: The simplest way to do this is to put something in a system filter along
4569 ==> if $message_size is above
4570 "${lookup{$sender_address}lsearch{/some/file}{$value}{10M}}"
4572 fail "Message is larger than $sender_address is allowed to send"
4575 In practice, an additional check that the message has arrived from your
4576 local host or local network is probably wise because sender addresses
4580 Q0720: I set \"accept hosts=192.168.122.96/32"\ in order to accept mail for
4581 relaying from my local LAN, but it doesn't work. What's wrong?
4583 A0720: 192.168.122.96/32 is not a network, it is a single host. Exim uses CIDR
4584 notation for specifying networks, where the number after the slash is
4585 the number of bits in the IP address that must match. Your setting says
4586 ``32 bits must match''. If you really mean to specify ``the next 32
4587 IP addresses'', you need 192.168.122.96/27.
4590 Q0721: I have POP-before-SMTP set up on my Exim server, but some clients use
4591 Outlook Express, which sends queued messages before checking the
4592 mailbox, so it doesn't work.
4594 A0721: Implement SMTP authentication.
4597 Q0722: I installed Amavis and it is working, but bounces are simply vanishing.
4599 A0722: Check that you haven't inadvertently set up the transport like this:
4603 command = "/usr/sbin/amavis -f ${sender_address} -d ${pipe_addresses}"
4605 The last line should be:
4607 ==> command = /usr/sbin/amavis -f <$sender_address> -d $pipe_addresses
4609 The important thing is the <> around the sender address; removal of
4610 the unnecessary "" and {} is just tidying. See the amavis FAQ at
4611 \?http://www.amavis.org/amavis-faq.php3?\.
4614 Q0723: I can't get Pine to work with PLAIN authentication; Exim keeps
4615 responding "535 Incorrect authentication data".
4617 A0723: You need to have this setting in your PLAIN authenticator:
4619 ==> server_prompts = :
4621 This is missing in the examples in early Exim documentation, because it
4622 was not realized that PLAIN authentication could be requested by a
4623 client without sending the data with the request. If the data is not
4624 sent, an empty prompt is expected.
4627 Q0724: I have used \":fail:"\ in some aliases; when one of these addresses is
4628 refused, I see the message on the log, but the response to the remote
4629 user is ``unknown user'' instead of the message from the alias file.
4630 How can I change this?
4632 A0724: Have you got a \message\ qualifier in the relevant ACL? Exim uses the
4633 message line in the ACL in preference to the message returned by the
4634 router. This is so you can restrict the amount of information that
4635 ``escapes'' from your site via SMTP if you want to. Remove the \message\
4636 line in the ACL entry that has \"verify = recipient"\ and your message
4639 Alternatively, if you are running Exim 4.10 or later, you can use the
4640 \$acl_verify_message$\ variable in your message to include the message
4641 from the router. See also Q0725.
4644 Q0725: I've set up some specific rejection messages for certain recipients, but
4645 when I test them, the SMTP message is always \*550 5.1.1
4646 <user@mydomain.com>... User unknown*\.
4648 A0725: That is not an Exim message (the ``5.1.1'' is a clue; Exim doesn't use
4649 those extended codes). You are probably being defeated by software that
4650 sees the 550 error code, and insists on putting in its own text. There
4651 is stupid software that does this. You can test Exim by using \-bh-\ or
4652 making a telnet call to the SMTP port. That way, there's no other
4653 software intervening.
4656 Q0726: My SMTP authentication can be bypassed by sending an unknown user name
4657 and an empty password. What is wrong with this condition in a PLAIN
4660 ==> server_condition = ${if eq{$2} {${lookup mysql{SELECT password FROM \
4661 accounts WHERE username='${local_part:$1}'}}}{1}{0}}
4663 A0726: Your lookup item returns an empty string when the user does not exist.
4664 You should instead arrange for the lookup to fail:
4666 ==> server_condition = ${if eq{$2} {${lookup mysql{SELECT password FROM \
4667 accounts WHERE username='${local_part:$1}'}{$value}fail}}{1}{0}}
4670 Q0727: When a message has many recipients, how can I stop SpamAssassin from
4671 being called for each of them? I'm running it from a pipe transport.
4673 A0727: In the transport configuration, set \batch_max\ to a value greater than
4677 Q0728: How do I use Exiscan, SA-Exim, SpamAssassin, Clam Antivirus, Sophos
4678 SAVI, or sophie with Exim?
4680 A0728: There's a mini-HOWTO about these available via
4681 \?http://www.timj.co.uk/linux/exim.php?\.
4682 See also sample configuration C047.
4685 Q0729: How can I screen out addresses that are neither valid usernames or
4686 distribution lists on mail being forwarded to an internal Win2K server?
4688 A0729: A user suggested using a router like this to do the recipient
4691 ==> verify_user_router:
4693 domains = win2kdomain.com
4695 ldap;user="cn=ldap-guest,cn=Users,dc=win2kdomain,dc=com"\
4697 ldap:://win2kpdc/dc=win2kdomain,dc=com?mailNickname?\
4698 sub?(&(mailNickname=$local_part)\
4699 (showInAddressBook=*)(sAMAccountName=*))
4702 Set up ldap-guest as a normal domain user on the Win2K PDC.
4704 Also, you need to set \no_verify\ on all the other routers that handle
4708 Q0730: How can I use the same passwords for SMTP authentication as I use for
4709 Courier IMAP access to my server?
4711 A0730: You can access the Courier authdaemon from an Exim authenticator. You
4712 must arrange for the Exim user (often \/exim/\ but sometimes \/mail/\)
4713 to be able to access \(/var/run/courier/authdaemon/socket)\. The
4714 configuration is something of a hack, but it is reported to work. Here
4715 is a LOGIN authenticator:
4720 server_prompts = Username:: : Password::
4721 server_condition = \
4722 ${if eq {${readsocket{/var/run/courier/authdaemon/socket}\
4723 {AUTH 76\n${length_76:exim\nlogin\n$1\n$2\
4724 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
4725 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
4726 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n}}}}{FAIL\n} {no}{yes}}
4729 Here is a PLAIN authenticator:
4735 server_condition = \
4736 ${if eq {${readsocket{/var/run/courier/authdaemon/socket}\
4737 {AUTH 76\n${length_76:exim\nlogin\n$2\n$3\
4738 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
4739 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
4740 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n}}}}{FAIL\n} {no}{yes}}
4744 Q0731: Is there any defence I can use against spam sent through an open proxy?
4746 A0731: The \*ident*\ feature can be used in some cases. See the discussion in
4750 Q0732: I would like to either warn or deny when a host uses an underscore in
4755 ==> helo_allow_chars = _
4757 This tells Exim not to reject the EHLO or HELO command immediately. Once
4758 you have done that, you can test for the underscore in an ACL. For
4759 example, to log a warning for hosts in your LAN, and reject for other
4760 hosts, you could do something like this:
4762 ==> deny message = Underscores are not valid in host names
4763 hosts = ! +lan_hosts
4764 condition = ${if match{$sender_helo_name}{_}{yes}{no}}
4766 ==> warn log_message = Accepted underscore from [$sender_host_address]
4767 condition = ${if match{$sender_helo_name}{_}{yes}{no}}
4770 Q0733: Is there any way to tell Exim not to lookup the IP address against any
4771 DNS black list if the connection is over IPv6?
4773 A0733: Use this condition in your ACL:
4775 ==> condition = ${if match{${mask:$sender_host_address/0}}\
4776 {${mask:::0/0}}{no}{yes}}
4778 From Exim 4.23 onwards, this can be simplified to
4780 ==> condition = ${if isip6{$sender_host_address}{no}{yes}}
4783 Q0734: How do MailScanner and Exiscan compare? What are the pros and cons?
4785 A0734: The big advantage of Exiscan is that it can reject messages at SMTP time
4786 before you have accepted responsibility for them, which means you don't
4787 have to deal with bouncing messages and thereby becoming a collateral
4790 The big advantage of MailScanner is that it gives you much greater
4791 control over the load on your machines. You configure it according to
4792 the maximum processing capacity of your computer and it will not exceed
4793 that; in fact because it deals with messages in batches the cost of
4794 processing a message actually goes down slightly as the load increases,
4795 because the per-batch costs are shared by more messages.
4797 With Exiscan, you have to rely on Exim's load protection mechanisms,
4798 which basically means that you have to stop accepting messages when your
4799 machine gets too loaded. This is bad if the machine happens to be an
4800 SMTP smarthost. You therefore need more overcapacity with Exiscan than
4804 Q0735: How can I block non-FQDNs in HELO/EHLOs?
4806 A0735: Many workstation clients send single-component names; take care that you
4807 do not block legitimate mail. With that proviso, you can do it using
4808 something like this in an ACL:
4810 ==> drop message = HELO doesn't look like a hostname
4811 log_message = Not a hostname
4812 condition = ${if match{$sender_helo_name} \
4813 {\N^[^.].*\.[^.]+$\N}{no}{yes}}
4815 This means: Drop the HELO unless it contains a dot somewhere in the HELO
4816 string, but the string may not begin or end with a dot. Thus, the
4817 imposed minimum length is 3 characters.
4819 The data for HELO/EHLO doesn't have to be a host name; it may
4820 legitimately be an IP address literal instead. The above test succeeds
4821 with an IPv4 address literal, but if you want also to accept IPv6
4822 address literals, you will have to modify the regular expression.
4825 Q0736: Is it possible to tell exim to drop the connection after a server
4826 attempts to send a message to a number of unknown users?
4828 A0736: Yes. Use \$rcpt_fail_count$\ and the \^drop^\ ACL command, as in this
4831 ==> drop message = Too many unknown users
4832 condition = ${if >{$rcpt_fail_count}{15}{yes}{no}}
4835 Q0737: Is there some way to tell Exim not to consider 127.0.0.1 as a valid MX?
4840 Q0738: How can I configure Exim to delay the SMTP connection if more than 10
4841 invalid recipients are received in one message?
4843 A0738: Put something like this in your RCPT ACL:
4845 ==> deny message = Max $rcpt_fail_count failed recipients allowed
4846 condition = ${if >{$rcpt_fail_count}{10} {1}}
4847 ! verify = recipient
4848 delay = ${eval: $rcpt_fail_count * 10}s
4849 log_message = $rcpt_fail_count failed recipient attempts
4851 This example increases the delay for each failed recipient.
4854 Q0739: Does Exim support SPF?
4856 A0739: An Exim ACL can be used. See \?http://spf.pobox.com/downloads.html?\.
4859 Q0740: How can I change the MAIL FROM address that is used for callouts?
4861 A0740: It depends on which type of callout you are using.
4863 (1) For envelope sender verification callouts, you cannot make any
4864 change. My view is that an envelope sender verification is testing
4865 whether Exim could send a bounce to that address. Therefore, it must
4866 use \"MAIL FROM:<>"\ because that is what it would do if it were
4867 sending a bounce message. If \"MAIL FROM:<>"\ is rejected, it means
4868 Exim could not send a bounce. Therefore the callout fails.
4870 (2) For verifying addresses in the ::From::, ::Sender::, or ::Reply-to::
4871 header lines (the \"verify = header_sender"\ condition), it is
4872 possible to make a change, on the grounds that these addresses are
4873 not necessarily ones that must accept bounce messages. You can do
4874 this by adding a \"mailfrom"\ option, like this:
4876 ==> require verify = header_sender/callout=mailfrom=abcd@x.y.z
4878 (3) It is also possible to make a change for the postmaster verification
4879 option, also on the grounds that a postmaster address need not
4880 accept bounces if it is never used as an envelope sender. Instead of
4881 just \"postmaster"\, \"postmaster_mailfrom"\ is used, like this:
4883 ==> require verify = sender/callout=postmaster_mailfrom=abcd@x.y.z
4885 (4) For recipient verification, there are three possibilities. The
4886 default is to use \"MAIL FROM:<>"\. If the \use_postmaster\ option
4887 is given, for example:
4889 ==> require verify = recipient/callout=use_postmaster
4891 then the address for MAIL FROM is made up from the local part
4892 \"postmaster"\ and the contents of \$qualify_domain$\.
4894 Alternatively, if the \use_sender\ option is given, the sender
4895 address of the incoming message is used. You should use this option
4896 only when you know that the receiving host makes use of the sender
4897 address when verifying. The reason is that the callout cache is much
4898 less effective in this case, causing many more callouts to be
4901 In all cases when you configure Exim to use a non-empty address in MAIL
4902 FROM during callout processing, you should think carefully about what
4903 might happen if this causes the called host to make its own callout back
4904 to your host. Make sure that callout loops cannot happen.
4907 Q0741: How can I get Outlook Express to use TLS when authenticating?
4909 A0741: If you check \"auth required"\ in OE, it will authenticate as soon as
4910 it sees AUTH LOGIN, in preference to STARTTLS. The trick is to
4911 advertise things to OE in a certain order. The first EHLO should
4912 advertise STARTTLS but not AUTH, and only the second EHLO (after TLS
4913 starts) should advert AUTH. One way of achieving this is to put, in
4914 the main section of your Exim configuration:
4916 ==> auth_advertise_hosts = ${if eq{$tls_cipher}{}{127.0.0.1}{*}}
4918 This means that the only host to which AUTH is advertised is 127.0.0.1
4919 when the session is not encrypted (that is, before TLS has started). The
4920 idea here is that there's no need for encryption for anything coming via
4921 the loopback interface. For an encrypted session, however, AUTH is
4922 advertised to all hosts.
4924 You can also block the AUTH command itself for unencrypted connections,
4925 by creating an ACL for \acl_smtp_auth\ that is something like this:
4927 ==> accept encrypted = *
4928 accept hosts = 127.0.0.1
4929 deny message = TLS encryption required before AUTH
4933 8. REWRITING ADDRESSES
4935 Q0801: How can I get Exim to strip the hostname from the sender's address?
4937 A0801: If you set up a rewriting rule in the following form:
4939 ==> *@*.your.domain $1@your.domain
4941 then Exim will rewrite all addresses in the envelope and the headers,
4942 removing anything between \"@"\ and \"your.domain"\. This applies to all
4943 messages that Exim processes. If you want to rewrite sender addresses
4944 only, the the rule should be
4946 ==> *@*.your.domain $1@your.domain Ffrs
4948 This applies the rule only to the envelope sender address and to the
4949 ::From::, ::Reply-to::, and ::Sender:: headers.
4952 Q0802: I have Exim configured to remove the hostname portion of the domain on
4953 outgoing mail, and yet the hostname is present when the mail gets
4956 A0802: Check the DNS record for your domain. If the MX record points to a CNAME
4957 record instead of to an A record, some MTAs (not Exim) are liable to
4958 rewrite addresses, changing your domain name to its ``canonical'' form,
4959 as obtained from the CNAME record.
4962 Q0803: I want to rewrite local addresses in mail that goes to the outside
4963 world, but not for messages that remain within the local intranet.
4965 A0803: You can use the \headers_rewrite\ option on a transport to do this.
4966 The rewriting will then apply to just those copies of a message that
4967 pass through the transport. The \return_path\ option can similarly be
4968 used to rewrite the sender address. There is no way of rewriting
4969 recipient addresses at transport time. However, as these are by
4970 definition remote addresses, you probably don't want to rewrite them.
4972 You have to set up the configuration so that it uses different SMTP
4973 transports for internal and external mail. If you are using a single
4974 router in both cases, you could configure it like this:
4978 transport = ${if match{$domain}{\N\.my\.domain$\N}{int_smtp}{ext_smtp}}
4980 This example uses the \%int_smtp%\ transport for domains ending in
4981 \(.my.domain)\, and \%ext_smtp%\ for everything else. The \%ext_smtp%\ transport
4982 could be something like this:
4986 headers_rewrite = *@*.my.domain \
4987 ${lookup{$1}cdb{/etc/$2/mail.handles.cdb}{$value}fail}
4989 ${if match{$return_path}{\N^([^@]+)@(.*)\.my\.domain$\N}\
4991 ${lookup{$1}cdb{/etc/$2/mail.handles.cdb}{$value}fail}\
4995 This example uses a separate file of local-to-external address
4996 translations for each domain. This is not the only possibility, of
4997 course. The \headers_rewrite\ and \return_path\ options apply the same
4998 rewriting to the header lines and the envelope sender address,
5002 Q0804: I'm using this rewriting rule to change login names into ``friendly''
5003 names, but if mail comes in for an upper case login name, it doesn't
5006 ==> *@my.domain ${lookup{$1}dbm{/usr/lib/exim/longforms}\
5007 {$value}fail}@my.domain bcfrtFT
5009 The longforms database has entries of the form:
5011 ==> ano23: A.N.Other
5013 A0804: Replace \"$1"\ in your rule by \"${lc:$1}"\ to force the local part to lower
5014 case before it is used as a lookup key.
5017 Q0805: Is it possible to completely fail a message if the rewrite rules fail?
5019 A0805: It depends on what you mean by ``fail a message'' and what addresses you
5020 are rewriting. If you are rewriting recipient addresses for your local
5023 ==> *@dom.ain ${lookup{$1}dbm{/wher/ever}{$value}{failaddr}} Ehq
5025 and in your alias file put something like
5027 ==> failaddr: :fail: Rewriting failed
5029 This fails a single recipient - others are processed independently.
5032 Q0806: I'm using \$domain$\ as the key for a lookup in a rewriting rule, but its
5033 contents are not being lowercased. Aren't domains supposed to be handled
5036 A0806: The value of \$domain$\ is the actual domain that appears in the address.
5037 It could of course be lower cased, but I know that would cause some
5038 unhappiness, because some people have mixed-case domain names which look
5039 silly if the case is changed. Thus, one wants to preserve the case in
5042 ==> *@*.TheRap.com something@$domain
5044 because ``therap'' doesn't look like two words. I know it seems trivial,
5045 but it is important to some people - especially if by some unfortunate
5046 accident the lowercased word is something indecent.
5048 You can trivally force lower casing by means of the \"${lc:"\ operator.
5049 Instead of \"$domain"\ write \"${lc:$domain}"\.
5052 Q0807: I want to rewrite local sender addresses depending on the domain of the
5055 A0807: In general, this is not possible, because a message may have more than
5056 one recipient and Exim keeps just a single copy of each message. It may
5057 also deliver one copy of a message with several recipient addresses.
5058 You can do an incomplete job by using a regular expression match in a
5059 rewrite rule to test, for example, the contents of the ::To:: header. This
5060 would work except in cases of multiple recipients.
5066 Q0901: I would like add some custom headers to selected outgoing mail based on
5067 a specific domain and the subject line.
5069 A0901: To the remote_smtp transport, add something like
5071 ==> headers_add = ${if and{\
5072 {eq{$domain}{spec.dom}}\
5073 {matches{$h_subject:}{whatever}}}\
5074 {Content-Type: text/html; charset="us-ascii"} fail }
5076 This example shows a ::Content-Type:: header, but you can have anything you
5077 like, and multiple headers can be inserted by using \"@\n"\ to separate them.
5080 Q0902: Is it possible to have Exim add a header to only certain local parts of
5083 A0902: Only if you arrange for each such local part to receive its own private
5084 copy of the mail. See \max_rcpt\ in the SMTP transport. If you set this
5085 to 1, you could use conditions in an expansion string to add or not add
5089 Q0903: How can I remove some part of the ::Received:: header?
5091 A0903: Set \received_header_text\.
5094 Q0904: How I can insert the PGP header line using Exim filters?
5096 A0904: You can't insert headers in a user filter. A system filter can do so,
5097 but the inserted lines then are included for all recipients.
5100 Q0905: I know I can use a system filter to replace certain headers in messages,
5101 but how can I add text to existing headers? I want to add [SPAM] to
5102 the subject line of messages that appear to be spam.
5104 A0905: You can only do this in a round about way, using filter commands like
5107 ==> headers add "New-Subject: SPAM: $h_subject:"
5108 headers remove subject
5109 neaders add "Subject: $h_new-subject:"
5110 headers remove new-subject
5112 This trick works only in system filters, where the commands are obeyed
5113 in order, and affect the master list of headers that apply to the whole
5114 message. You cannot do this with the \headers_add\ and \headers_remove\
5121 Q1001: I'm running a large mail server. Should I set \split_spool_directory\ to
5122 improve performance?
5124 A1001: Splitting the spool directory has most benefit if there are times when
5125 there are a large number of messages on the queue. If all mail is
5126 delivered very quickly, and the queue is always less than, say, a few
5127 hundred messages, there isn't any need to do this. With larger queues,
5128 there is a definite performance benefit to splitting the spool. It shows
5129 up earlier on some types of file system, compared with others.
5131 Exim was not designed for handling large queues. If you are in an
5132 enviroment where lots of messages remain on the queue for long periods
5133 of time, consider implementing a back up host to which you pass these
5134 messages, so that the main host's queue remains short. You can use
5135 \fallback_hosts\ to do this, or a router that is conditional on
5139 Q1002: How well does Exim scale?
5141 A1002: Although the author did not specifically set out to write a high-
5142 performance MTA, Exim does seem to be fairly efficient. The biggest
5143 server at the University of Cambridge (a large Sun box) goes over
5144 100,000 deliveries per day on busy days (it has over 20,000 users).
5145 There was a report of a mailing list exploder that sometimes handles
5146 over 100,000 deliveries a day on a big Linux box, the record being
5147 177,000 deliveries (791MB in total). Up to 13,000 deliveries an hour
5150 These are quotes from some Exim users:
5152 "... Canada's largest internet provider, uses Exim on all of our mail
5153 machines, and we're absolutely delighted with it. It brought life back
5154 into one of our machines plagued with backlogs and high load averages.
5155 Here's just an example of how much email our largest mail server
5156 (quad SS1000) is seeing ... " [230,911 deliveries in a day: 4,475MB]
5158 "... Exim has to ... do gethostbyname()s and RBL lookups on all of the
5159 incoming mail servers, and he runs from inetd (TCP Wrappers connected).
5160 All the same, it seems to me that he runs as fast as lightning on our
5161 SCO 5.0.4 box (1 Pentium 166) - far faster than MMDF which I (and many
5162 customers) had before."
5164 "On a PII 400 with 128M of RAM running Linux 2.2.5, I have achieved
5165 36656 messages per hour (outgoing unique messages and recipients). For
5166 about a 5 minute period, I was able to achieve an average of 30 messages
5167 per second (that would be 108000 m/hour)! We are using: (options that
5171 split_spool_directory
5173 remote_max_parallel = 1
5175 We have a cron job hat runs every five minutes that spawns 5 \"exim -q"\ if
5176 there are less that 120 exim processes currently running. We found
5177 that by manually controlling the concurrency of \"exim -q"\ processes
5178 contending for the spool for \%remote_smtp%\ delivery that we gained
5179 considerable performance - 10000 m/hour."
5182 Q1003: We have a large password file. Can Exim use alternative lookups during
5183 delivery to speed things up?
5185 A1003: If you are using FreeBSD, this problem should not arise, because it
5186 automatically uses an indexed password file. In some other operating
5187 systems you can arrange for this to happen too. On Linux, for example,
5188 all you need to do is
5193 and put \"db"\ before \"files"\ in any \(/etc/nsswitch.conf)\ lines you want to
5196 On systems that do not include support for indexed password files, you
5197 can build one yourself, and reference it from the Exim configuration.
5198 For example, for routing to local mailboxes you could use this:
5202 condition = ${lookup{$local_part}cdb{/etc/passwd.cdb}{yes}{no}}
5203 transport = local_delivery
5204 user = ${extract{1}{:}{${lookup{$local_part}cdb{/etc/passwd.cdb}}}
5206 This assumes a cdb version of the password file.
5209 Q1004: I just wondered if it might be helpful to put the hints database on a
5210 RAM disk during regular operation. Did anybody try that yet?
5212 A1004: A user reported thus: ``I have found that this works great under Solaris.
5213 Make a RAM disk partition and keep everything in the \(db)\ directory on
5214 it. However, when I try the same thing on Linux, I don't see the same
5215 boost. I think that Linux's file buffer cache works about the same.
5216 Plus, this leave more room for processes to run.''
5218 There have been other reports that Linux's delayed buffer write provides
5219 better overall performance in general.
5221 Apparently there is support in the Solaris kernel for a delayed writing,
5222 as in Linux, but Sun's server policy is to have it disabled so that you
5223 don't lose so much if the server crashes. There is a program called
5224 \^fastfs^\ to enable and disable this support. You have to download and
5225 compile it yourself; find it by looking for \"fastfs.c"\ in a search
5226 engine. Solaris performance is reported to be much improved, but you
5227 should take care to understand the potential hazards. In particular,
5228 \^fsck^\ may be unable to ``fix'' disks automatically after a crash.
5231 Q1005: A lot of incoming mail is pushing up my system load too much, and there
5232 are many Exim processes. How can I control this?
5234 A1005: Have you set any of the Exim configuration options that limit what it
5235 does under high load? For example, queue_only_load, deliver_queue_load_max?
5236 See the list in the section entitled \*Resource control*\ in the manual.
5238 It sounds like a lot of simultaneous incoming mail pushes your system
5239 into uncontrolled overload. The multiple Exim processes are probably
5240 just multiple incoming messages. You can use the \^exiwhat^\ utility to
5247 Q1101: How do I set up Majordomo to work with Exim?
5249 A1101: Users have found several ways of setting up Exim for use with Majordomo.
5250 One way has been documented at
5251 \?http://www.averillpark.net/exim/majordomo.html?\.
5253 Somewhere in the Majordomo docs or FAQ it mentions using batchmail or
5254 other additional programs to improve the performance of large lists.
5255 They are not needed with Exim, and their use can actually make things
5256 worse. However, it's a good idea to set \remote_max_parallel\ to a value
5257 greater than 1 in the Exim configuration.
5260 Q1102: I have set \$mailer$\ in \(majordomo.cf)\, but it still isn't setting the
5261 sender correctly in the messages it sends.
5263 A1102: Make sure you have got the quoting correct in the \$mailer$\ setting. For
5266 ==> $mailer = "$sendmail_command -oi -oee -f$sender\@lists.mydomain.de";
5268 is not correct. It needs three backslashes, not one, and the $ at the
5269 start of \$sender$\ has to be escaped with a backslash.
5272 Q1103: I'm trying to set up majordomo, but I'm getting a wrong mode error
5273 when I try to send it mail.
5275 A1103: Check the mode of \(/var/lib/majordomo/lists/lists.aliases)\ and compare it
5276 with the setting of the \modemask\ option in the Majordomo aliases
5277 router. This option specifies bits which must not be set for the alias
5278 file, and it defaults to 022.
5281 Q1104: I'm getting return code 9 from \(/home/majordomo/majordomo-1.94.4/wrapper)\
5282 when it is passed a message from Exim.
5284 A1104: A problem like this turned out to be the Perl version that came with
5285 RedHat 5.2. Rebuilding Perl 5.005x solved it.
5288 Q1105: Exim is complaining about an invalid command line when Majordomo tries
5289 to send it a message for delivery.
5291 A1105: Take a look at your \(majordomo.cf)\ file, It should have something that
5294 ==> $sendmail_command = "/usr/lib/sendmail";
5296 and another line like
5298 ==> $mailer = "$sendmail_command -oi -oee -f\$sender";
5300 If you have modified \^resend^\ (one of the majordomo programs) to use
5301 \$sendmail_command$\ instead of \$mailer$\ you will be calling Exim with no
5302 command line arguments.
5308 Q1201: When I run fetchmail, I get the error \*SMTP listener doesn't like
5309 recipient address xxx@localhost*\.
5311 A1201: Make sure that //localhost// is recognized as a domain that is to be
5312 delivered locally. If you are using the default Exim run time
5313 configuration, you'll see a line near the top like this:
5315 ==> domainlist local_domains = @
5319 ==> domainlist local_domains = @ : localhost
5322 Q1202: I'm currently using Exim with fetchmail and I'd like to use the RBL on
5323 Exim, but will it work? Do I need to configure fetchmail any particular
5324 way? As far as Exim knows, all mail is coming from 127.0.0.1. Will it
5325 check the source address against RBL? Or will it check the ::From:: header?
5327 A1202: It will check 127.0.0.1 (not very useful). The point of the RBL is to
5328 keep messages from black-listed hosts out of your machine. If you are
5329 using fetchmail, you have got the messages into your machine before you
5330 approach Exim. That kind of defeats the purpose of the RBL. The right
5331 way to do this would be for the host from which you fetch your mail to
5332 do the RBL checking and insert some kind of warning header for you to
5333 test, as Exim does if you run RBL checks in warning mode.
5339 Q1301: Exim built with Perl support exits with the error message \*./exim: can't
5340 load library 'libperl.so'*\.
5342 A1301: If you are using BSDI, see Q9401.
5345 Q1302: Exim built with Perl support exits with several error messages of the
5346 form \*undefined reference to `PL_stack_sp'*\.
5348 A1302: This has been seen on FreeBSD systems that had two different versions of
5349 Perl installed, the older with an \^a.out^\ library and the newer with an
5350 ELF library. Ensure that the older package is removed.
5354 14. DIAL-UP AND ISDN
5356 Q1401: When I'm not connected to the Internet, how can I arrange for mail to
5357 other hosts on my local network to be delivered, while at the
5358 same time mail to Internet hosts is queued without any delivery
5361 A1401: Use the \queue_domains\ option to control which domains are held
5362 on the queue for later delivery. For example,
5364 ==> queue_domains = ! *.localnet
5366 allows delivery to domains ending in \(.localnet)\, while queueing all the
5370 Q1402: I have a dial-up machine, and I use the \queue_smtp_domains\ option so
5371 that remote mail only goes out when I do a queue run. However, any email
5372 I send with an address \(anything@aol.com)\ is returned within about 15
5373 minutes saying \*retry time exceeded*\, and all addresses are affected.
5375 A1402: You should be using \queue_domains\ rather than \queue_smtp_domains\.
5376 With the latter, Exim is trying to route the addresses, which involves a
5377 DNS lookup. This is presumably timing out, causing a retry time to be
5378 set for the domain, and somehow a valid lookup never happened before the
5379 maximum retry time (default of 4 days) passed. Hence the bounce. The
5380 fact that it is \(aol.com)\ is probably not relevant. You should probably
5381 also be using \-qq-\ to do your queue run rather than \-q-\.
5384 Q1403: How should Exim be configured when it is acting as a temporary storage
5385 system for a domain on a dial-up host?
5387 A1403: Exim isn't really designed for this, but... The lowest-numbered MX
5388 record for the domain should be pointing to the dial-up host. A higher
5389 numbered MX record (lower priority) should point to the Exim server that
5390 is acting as a temporary storage system.
5392 You should set a large retry time for the domain, so that Exim doesn't
5393 keep trying to deliver when the host is offline. When the host comes
5394 online, the waiting messages have to be kicked somehow. This can be done
5395 by calling Exim with the \-R-\ option, or via the SMTP ETRN command.
5397 This works provided the number of messages is low. If you are handling
5398 lots of mail, keeping messages waiting for their host to connect and
5399 those that are having delivery problems to remote hosts all in the same
5400 queue doesn't work so well. It is better in this case to get Exim to
5401 deliver the mail for the dial-in hosts into some local files which then
5402 get transmitted by other software when the host connects. One tool for
5403 doing this can be found at \?http://cr.yp.to/serialmail.html?\.
5405 For further discussion, see section entitled \*Intermittently connected
5406 hosts*\ in the manual, and also the section in the Exim book with the
5410 Q1404: I have \queue_domains\ or \queue_smtp_domains\ set, and use \-qf-\ to
5411 force delivery of waiting mail when I dial in. How can I arrange for any
5412 new messages that arrive while I'm connected to be delivered immediately?
5414 A1404: Instead of \queue_domains\ or \queue_smtp_domains\, use the \queue_only_file\
5415 option. This causes messages to be queued if a particular file exists.
5416 If you put the word ``smtp'' before the file name, the queueing applies
5417 only to domains that are delivered by SMTP, thus not affecting local
5420 ==> queue_only_file = smtp/etc/present/when/not/connected
5422 Then, in the scripts which are run when you connect and disconnect,
5423 arrange to remove the file after connection, and create it just before
5427 Q1405: I have an ISDN connection and would like a way of running the queue
5428 automatically when it is up.
5430 A1405: The following shell commands test for the interface being up and then
5433 ==> ifconfig ppp0 | fgrep UP >/dev/null
5434 if [ $? -eq 0 ] ; then exim -q ; fi
5436 You could put these commands into a script which runs them at regular
5437 intervals. You might want to use \-qq-\ instead of \-q-\.
5439 With Linux, the script \(/etc/ppp/ip-up)\ is run after a ISDN connection
5440 or a more general PPP connection has been established. If you are using
5441 Linux, you could put the call to Exim in that script.
5444 Q1406: When I dial up to collect mail from my ISP, only the first 10 messages
5445 get delivered immediately; the remainder just sit on the queue until a
5446 queue runner process finds them.
5451 Q1407: RFC 1985 specifies that the SMTP command \"ETRN host.domain"\ causes all
5452 mail queued for that host, no matter what domain it's for, to be
5453 delivered. Why doesn't Exim support this?
5455 A1407: Exim does not keep queues of mail for specific destinations. It just
5456 keeps one pool of undelivered messages. What is more, once you start a
5457 delivery of a message, it tries to deliver to all the addresses in the
5458 message, not just the one you may be interested in. (Of course, this
5459 doesn't usually do any harm.)
5461 The only way it could be done within Exim would be, for every message
5462 on the queue, to go through the motions of routing each undelivered
5463 address and see if that resulted in a delivery to the host of interest.
5464 This could be extremely expensive (e.g. 1,000 messages on the queue,
5465 only 1 for the given host).
5467 The bottom line is that Exim just wasn't designed for this kind of
5468 operation, that is, holding messages for intermittently connected hosts.
5469 The queueing arrangements are designed for handling delivery problems
5470 that are not expected to be common.
5472 A better way to do this is to implement the required queues separately.
5473 After all, keeping such mail on an active queue (where Exim will keep
5474 trying to deliver) is silly. If there is a lot of mail for these hosts,
5475 it also masks genuine delivery problems when you inspect the queue.
5477 Large ISPs who provide this kind of functionality do not usually leave
5478 waiting mail on the MTA's queue. Instead, they get it delivered into
5479 per-host directories, one message per file, in one of the special
5480 formats (BSMTP, maildir, or mailstore) and when an ETRN arrives, it
5481 kicks off some completely different program that establishes an SMTP
5482 connection to the host and shovels the waiting mail down it. That seems
5483 to me to be a much neater way of doing this. It means you can easily add
5484 additional functionality such as archiving or throwing away uncollected
5487 One program that has this functionality is \^ssmtp^\, which can be
5488 found in \?ftp://metalab.unc.edu/pub/Linux/system/mail/mta/?\.
5489 Alternatively, sample configuration C037 demonstrates an elegant way of
5490 using Exim itself to deliver the saved messages when the client issues
5494 Q1408: If email has been deferred to a member on a local mailing list
5495 (implemented through forward files), and one of our ETRN clients is on
5496 this mailing list, the \-R-\ won't flush the mailing list message for
5499 A1408: That is because \-R-\ matches only original recipient addresses, not those
5500 produced as a result of expansion, because these are not (by default)
5501 preserved from delivery to delivery. You can get round this by setting
5502 \one_time\ on the forwarding router, but you are not allowed to have
5503 expansions to pipes or files on routers that have \one_time\ set.
5504 Therefore, you will have to have a separate router for mailing lists
5505 (with \one_time\ set) to the one used for normal forward files that might
5506 specify pipe or file deliveries. However, the problem will still be
5507 present for any user who sets up a \(.forward)\ file to redirect to any of
5508 the ETRN domains. See the last 3 paragraphs of Q1407 for a discussion of
5509 an alternative approach.
5512 Q1409: I would like to have a separate queue per domain for hosts which dial
5513 in to collect their mail.
5515 A1409: Exim isn't really designed for this kind of operation. The only way to
5516 do this would be to cause it to send those messages to a differently
5517 configured version of Exim with its own spool area. This could be done
5518 via a pipe or SMTP to a private port. The main Exim, listening on port
5519 25, would then be configured to run an appropriate command to prod one
5520 of the others when it received ETRN, by means of the \smtp_etrn_command\
5523 You could probably manage this with a single Exim binary and a number of
5524 different configuration files, passed to the special versions using the
5525 \-C-\ option. For this application they could all run as \^exim^\, since no
5526 root privilege would be needed.
5528 An alternative approach id to get Exim to deliver mail for such hosts
5529 in batch SMTP format into some directory, and have the ETRN run
5530 something to pass such messages to the dialled-in host. See also Q1403.
5536 Q1501: The MX records for some UUCP domains point to my local host. How do I
5537 get it to pass the messages on to UUCP?
5539 A1501: The simplest way is to create a file containing a list of domains, and
5540 the hosts to which their messages should be sent, like this:
5542 ==> uucp1.domain.example: uucp1.host.example
5543 uucp2.domain.example: uucp2.host.example
5546 Then you can use a router like this:
5550 domains = lsearch;/etc/uucp/domains
5551 transport = uucp_transport
5553 and a transport like this:
5558 command = /usr/local/bin/uux - -r $domain_data!rmail $local_part
5561 The \$domain_data$\ variable retains the value that is looked up when
5562 the \domains\ option in the router is matched.
5565 Q1502: How can I get Exim to handle ``bang path'' addresses?
5567 A1502: In general, you can't (Exim is an Internet mailer and recognizes only
5568 RFC 2822 domain-style addresses) but some restricted kinds of bang path
5569 can be dealt with by appropriate rewriting - but please note the warning
5572 Exim treats a bang path address as an unqualified local part, and so
5573 will qualify it with your domain. A rule such as
5575 ==> \N^([^!]+)!(.+)@your\.domain$\N $2@$1
5577 turns \(a!b@your.domain)\ into \(b@a)\. You can also use a repeating rule to
5578 turn multi-component paths into the ``percent hack'' notation with a rule
5581 ==> \N^([^!]+)!([^@%]+)(.+)$\N $2%$1$3 R
5583 which turns \(a!b@c)\ into \(b%a@c)\ and \(a!b!c@d)\ first into \(b!c%a@d)\ and then,
5584 because of the R flag, into \(c%b%a@d)\. The R flag causes repetition up to
5587 \**Warning:**\ If you install a general rewriting rule like the above, you are
5588 opening yourself up to the possibility of unwanted relaying. A host that
5589 is not permitted to relay through your system could send a message with
5590 an SMTP command line such as
5592 ==> RCPT TO:<victim-host!victim-user@your.domain>
5594 and this would be accepted because it is addressed to your domain.
5595 However, the rewriting then converts the address, and the message does
5596 in fact get relayed. One way round this, if all your bang path messages
5597 are passed to Exim via SMTP, is to use the \"S"\ rewriting flag. This
5598 applies a rewriting rule to incoming SMTP addresses as soon as they are
5599 received, before checking for qualification, relaying, etc. So a rule
5602 ==> \N^([^!]+)!(.+)$\N $2@$1 S
5604 rewrites simple two-component bang paths before the result is checked
5605 for relaying. However, this does not rewrite addresses in the headers of
5609 Q1503: We see something strange on our system in regards to mail coming in via
5610 rmail from a UUCP link. The sender is being set to mailmaster instead of
5611 the real sender, and a ::Sender:: header is being added to the message.
5613 A1503: If \(mailmaster)\ is the user that is running rmail, you need to include
5614 that user in the \trusted_users\ configuration option. Only trusted users
5615 are permitted to specify senders when mail is passed to Exim via the
5620 16. MODIFYING MESSAGE BODIES
5622 Q1601: How can I add a disclaimer or an advertisement to a message?
5624 A1601: There are a number of technical and potential legal problems that arise
5625 in connection with message modification. Some of them are listed below.
5626 Some comment on the legal position of email disclaimers in English law
5627 can be found at \?http://www.weblaw.co.uk/artemail.htm?\.
5629 See also \?http://www.goldmark.org/jeff/stupid-disclaimers/?\. There is
5630 some discussion about the problems of actually adding disclaimers in
5631 \?http://www.goldmark.org/jeff/stupid-disclaimers/apply.html?\.
5633 In many cases, email disclaimers will make your company look ridiculous,
5634 at the very least. At worst, they may interfere with the normal
5637 If, despite these considerations, you still want to modify messages, you
5638 can do so using Exim, but not directly in Exim itself. It is not the job
5639 of an MTA to modify messages, something that requires understanding of
5640 their content and format.
5642 Exim provides a hook called a ``transport filter'' that lets you pass
5643 any outgoing message through a program or script of your choice. It
5644 is the job of this script to make any changes to the message that you
5645 require. By this means, you have full control over what changes are
5646 made, and Exim does not need to know anything about message bodies.
5647 However, using a transport filter requires additional resources, and may
5648 slow down mail delivery.
5650 You can use Exim's routers to arrange for those messages that you want
5651 to modify to be delivered via a transport filter. For example, suppose
5652 you want to do this for messages from addresses in your domain that are
5653 being delivered to a remote host. First you need to set up a special
5654 \%smtp%\ transport that uses a filter, like this:
5656 ==> remote_smtp_filter:
5658 transport_filter = /your/filter/command
5660 Then you need to modify the \%dnslookup%\ router to use this transport
5661 when the conditions are right:
5665 domains = ! +local_domains
5666 transport = ${if eq {$sender_address_domain}{your.domain}\
5667 {remote_smtp_filter}{remote_smtp}}
5668 ignore_target_hosts = 127.0.0.0/8
5671 This is the standard \%dnslookup%\ router, but with a modified setting of
5672 the \transport\ option. When the sender address is in your domain, it
5673 routes to the special transport instead of the standard one.
5675 The entire message is passed to your filter command on its standard
5676 input. It must write the modified version to the standard output, taking
5677 care not to break the RFC 2822 syntax. The command is run as the Exim
5680 There are a number of potential problems in doing this kind of
5681 modification in an MTA. Many people believe that to attempt is it wrong,
5684 1. It breaks digital signatures, which are becoming legally binding
5685 in some countries. It may well also break encryption.
5687 2. It is likely to break MIME encoding, that is, it is likely to wreck
5688 attachments, unless great care is taken. And what about the case of a
5689 message containing only binary MIME parts?
5691 3. It is illegal under German and Dutch law to change the body of
5692 a mail message in transit. It might potentially be illegal in
5693 the UK under European law. This consideration applies to ISPs and
5694 other ``common carriers''. It would presumably not apply in a corporate
5695 environment where modification was done only to messages originating
5696 from the employees, before they left the company's network. It might
5697 also not apply if the senders have explicitly given their consent
5698 (e.g. agreed to have advertisements added to their incoming mail).
5700 4. Since the delivered message body was produced by the MTA (not the
5701 originator, because it was modified), the MTA operator could
5702 potentially be sued for any content. This again applies to `common
5703 carrier' MTAs. It's interesting that adding a disclaimer of liability
5704 could be making you liable for the message, but this case seems
5705 more likely to involve adding advertisements than disclaimers. After
5706 all, no postal service in the world opens all the mail it carries to
5709 5. Some mail clients (old versions of MS outlook) crash if the message
5710 body of an incoming MIME message has been tampered with.
5712 There are also potential problems that could arise if a scheme to add
5713 disclaimers goes wrong for some messages:
5715 1. False negatives: `Ah, this guy usually says he does not represent
5716 their views, but in this message he doesn't have the disclaimer'.
5718 2. False positives: `This official announcement does not represent our
5721 An alternative approach to the disclaimer problem would be to insist
5722 that all relevant messages have the disclaimer appended by the MUA. The
5723 MTA should refuse to accept any that do not. Again, however, the MTA
5724 must understand the format of messages in order to do this. Simply
5725 checking for appropriate wording at the end of the body is not good
5726 enough. It would probably be necessary to run a Perl script from within
5727 an Exim system filter, or write a \^^local_scan()^^\ function in order
5728 to adopt this approach.
5730 Finally, it's a trivial matter to add customized headers of the sort:
5732 ==> X-Disclaimer: This is a standard disclaimer that says that the views
5733 X-Disclaimer: contained within this message are somebody else's.
5735 which is a much easier alternative to modifying message bodies.
5738 Q1602: How can I remove attachments from messages?
5740 A1602: The answer to this is essentially the same as for Q1601.
5744 17. ENCRYPTION (TLS/SSL)
5746 Q1701: I am trying to set up an Exim server that uses a self-signed certificate
5747 to enable my clients to use TLS. However, clients other than Exim
5748 refuse to accept this certificate. What's wrong?
5750 A1701: It seems that some clients require that the certificate presented by
5751 the server be a user (also called ``leaf'' or ``site'') certificate, and not
5752 a self-signed certificate. In this situation, the self-signed
5753 certificate must be installed on the client as a trusted root
5754 \*certification authority*\ (CA), and the certificate used by the server
5755 must be a user certificate signed with that self-signed certificate.
5757 For information on creating self-signed CA certificates and using them
5758 to sign user certificates, see the \*General implementation overview*\
5759 chapter of the Open-source PKI book, available online at
5760 \?http://ospkibook.sourceforge.net/?\. Here is a quick overview. First,
5763 \?http://www.FreeBSD.org/cgi/mid.cgi?id=3C3F3A93.C1ECF9B0%40mindspring.com?\
5765 Then, follow the instructions found on these two (consecutive) pages:
5767 \?http://ospkibook.sourceforge.net/docs/OSPKI-2.4.6/OSPKI/initialisation.htm?\
5768 \?http://ospkibook.sourceforge.net/docs/OSPKI-2.4.6/OSPKI/keygensign.htm?\
5770 Two points on the PKI Book literature:
5772 (1) It's assumed that it's okay to use a passphrase-protected key to
5773 encrypt the user/site/leaf certificate. If this isn't acceptable,
5774 you seem to be able to strip out the passphrase as follows:
5776 ==> openssl rsa -in user.key -our user.key.new
5779 This should be done immediately after \(user.key)\ is created.
5781 (2) The \*sign.sh*\ script is available in the \*mod_ssl*\ distribution,
5782 available at \?http://www.modssl.org/source/?\.
5784 Having followed the instructions, you end up with the following files:
5788 This file should be installed into the client software as a trusted
5789 root certification authority. In Windows XP, this can be done as follows:
5791 \#\#Call the file \(ca_cert.cer)\
5793 \#\#Double-click on the file
5795 \#\#"Install Certificate";
5799 \#\#"Place all certificates in the following store"
5803 \#\#"Trusted Root Certification Authorities"
5815 (b) \(user.crt)\ and \(user.key)\
5817 These files should be installed into the server software. In Exim, this
5818 can be done by adding these lines to the configuration file:
5820 ==> tls_certificate = /usr/local/etc/exim/tls_cert
5821 tls_privatekey = /usr/local/etc/exim/tls_key
5823 Then install \(user.crt)\ and \(user.key)\ under the names \(tls_cert)\
5824 and \(tls_key)\ in the appropriate directory.
5827 Q1702: How can I arrange for Exim to advertise support for SMTP authentication
5828 only when the session is encrypted?
5830 A1702: Use this setting:
5832 ==> auth_advertise_hosts = ${if eq{$tls_cipher}{}{}{*}}
5835 Q1703: I have some legacy clients that don't use STARTTLS, but which expect to
5836 negotiate a TLS session automatically on connection to the ssmtp port
5837 (465). Can Exim handle this?
5839 A1703: If you are using release 4.43 or later, you can set
5841 ==> tls_on_connect_ports = 465
5843 and then arrange for your daemon to listen on both port 25 and port 465
5844 by setting \daemon_smtp_ports\ or \local_interfaces\ or the \-X-\
5845 command line option. Or use \(inetd)\ to listen on port 465.
5847 If you are using an earlier release of Exim, you need to run two
5848 Exim listeners, on different ports, one of which is started with the
5849 \-tls-on-connect-\ option (which makes all ports act this way). You can
5850 either use two daemons, or a single daemon, with the other listener
5851 using \^inetd^\. For example, here are commands to start two daemons:
5854 exim -bd -oX '[0.0.0.0]::465' -tls-on-connect
5856 The first is a ``normal'' daemon; the second listens on port 465 and
5857 expects to negotiate a TLS session at the start of each connection.
5860 Q1704: When my Outlook Express 6.0 client sends a STARTTLS command to begin a
5861 TLS session, Exim doesn't seem to receive it.
5866 Q1705: I have listed some hosts in \tls_try_verify_hosts\, but when they
5867 connect, no data appears in \$tls_peerdn$\.
5869 A1705: This means that the clients have not sent certificates when asked by
5870 the server to do so. If the clients are running Exim, check that
5871 \tls_certificate\ is correctly set in their \%smtp%\ transports. Note
5872 that this value is not automatically inherited from the global
5873 \tls_certificate\ option.
5876 Q1706: I have listed some hosts in \tls_verify_hosts\ and provided them with
5877 certificates, but their connections are always rejected.
5879 A1706: Make sure that the server file containing the expected certificates
5880 (defined by \tls_verify_certificates\) is readable by the Exim user.
5881 See also the answer to Q1705.
5884 Q1707: I am trying to use TLS with Evolution as a client, and keep seeing this
5885 error: \*SMTP protocol violation: synchronization error (next input
5886 sent too soon): rejected "\200F^A^C".*\ What does it mean?
5888 A1707: See Q0086 for a general explanation of the error. In this case, it
5889 probably means that Evolution is trying to negotiate a TLS session
5890 immediately it connects, without first using the STARTTLS command. This
5891 was an older way of starting up TLS, before STARTTLS was defined. See
5892 Q1703 for how to deal with this.
5895 Q1708: I trying to use TLS with Outlook as a client on a box that is running
5896 Norton Antivirus, but all my email is being rejected with \*Unsupported
5897 command*\ errors. Why?
5899 A1708: Norton Antivirus does not support TLS or AUTH. It puts a broken SMTP
5900 proxy between you and the Exim server. You need to turn off outbound
5907 Q2000: Are there any Y2K issues with Exim?
5909 A2000: The author of Exim believes that it is Y2K-compliant, as long as the
5910 underlying operating system and C library are. Exim does not parse dates
5911 or times at all. Internally, it makes some use of binary timestamps in
5912 Unix format (number of seconds since 1-Jan-1970) and uses C library
5913 services to convert these to printing forms (e.g. for logging). The
5914 printing forms all use 4-digit years. Some people have tried various
5915 tests. No problems have been reported, but details of what tests have
5916 been done are not available.
5918 Well, it's now November 2001, and no Y2K problems have been reported, so
5919 it looks like I was right. This entry is retained as historical
5926 Q5001: How can I arrange to allow a limited set of users to perform a limited
5927 set of Exim administration functions? I don't want to put them all in
5930 A5001: See \?http://www.chiark.greenend.org.uk/~ian/userv/?\. Using \^userv^\ you can
5931 arrange (for example) for certain users to be able to invoke \^mailq^\ or
5932 \^runq^\ or other preset commands as \^exim^\ (or any other user, as configured)
5933 with only \^userv^\ configuration. If you want to check the particular Exim
5934 options available you can easily do it with shell or Perl scripts and
5935 \^userv^\ configuration, and provided you know how to do argument
5936 ``unparsing'' properly in shell or Perl it will be secure.
5939 Q5002: I want to ``tail'' the Exim log, but I have a number of other logs I also
5940 want to ``tail'', and the number of tailing windows is getting to be a
5943 A5002: Look for a program called \^xtail^\ (despite its name, it's not an
5944 X-windows application). It allows you to do multiple tails, even of
5947 Alternately, get the GNU version of \^tail^\, from the GNU textutils
5948 package (\?ftp://ftp.gnu.org/gnu/textutils/?\). GNU tail lets you run
5949 \"tail -f\" on multiple files at the same time, although it doesn't work
5950 on entire directories like \^xtail^\ can. If you are running Linux, you
5951 probably already have a version of GNU \^tail^\ that can follow multiple
5955 Q5003: How can I persuade Exim to accept ETRN commands without the leading
5958 A5003: Set the option
5960 ==> smtp_etrn_command = /usr/lib/sendmail -R $domain
5962 This causes Exim to run that command, with \$domain$\ replaced by the
5963 argument of ETRN. The default action of Exim is to require the # sign
5964 in order to be RFC-compliant, and to run the equivalent of
5966 ==> smtp_etrn_command = /usr/lib/sendmail -R ${substr_1:$domain}
5968 which uses the argument without the leading # as the value for the \-R-\
5969 option. You aren't restricted to running Exim with the \-R-\ option, of
5970 course. You can specify any command you like, with any number of
5971 arguments. In particular, you can pass over the IP address of the caller
5972 via \$sender_host_address$\. However, if you make use of expansion strings
5973 in the arguments, each one must be entirely contained in a single
5974 argument. For example, if you want to remove the first character of the
5975 ETRN argument when it is @ or #, you could use
5977 ==> smtp_etrn_command = "/usr/lib/sendmail -R \
5978 \"${if match {$domain}{^[@#]}{${substr_1:$domain}}{$domain}}\""
5980 The internal quotes are necessary because of the white space inside the
5984 Q5004: I've recently noticed that emails I send with a ::Bcc:: line are being
5985 delivered to their final destination with the ::Bcc:: line still present.
5987 A5004: Exim removes ::Bcc:: lines only if you call it with the \-t-\ option (i.e.
5988 when it is acting partly as an MUA). It does not remove ::Bcc:: lines that
5989 are present in incoming SMTP mail or command-line mail that does not
5990 use \-t-\. Indeed, it should not remove them, because only the
5991 initiating software (i.e. the MUA) can tell what to do with ::Bcc::
5992 lines; any MTA software has to leave them alone. This is what RFC 2822
5993 has to say about ::Bcc::
5995 \*The ::Bcc:: field (where the ``Bcc'' means ``Blind Carbon Copy'') contains
5996 addresses of recipients of the message whose addresses are not to be
5997 revealed to other recipients of the message. There are three ways in
5998 which the ::Bcc:: field is used. In the first case, when a message
5999 containing a ::Bcc:: field is prepared to be sent, the ::Bcc:: line is
6000 removed even though all of the recipients (including those specified
6001 in the ::Bcc:: field) are sent a copy of the message. In the second
6002 case, recipients specified in the ::To:: and ::Cc:: lines each are sent
6003 a copy of the message with the ::Bcc:: line removed as above, but the
6004 recipients on the ::Bcc:: line get a separate copy of the message
6005 containing a ::Bcc:: line. (When there are multiple recipient
6006 addresses in the ::Bcc:: field, some implementations actually send a
6007 separate copy of the message to each recipient with a ::Bcc::
6008 containing only the address of that particular recipient.) Finally,
6009 since a ::Bcc:: field may contain no addresses, a ::Bcc:: field can be
6010 sent without any addresses indicating to the recipients that blind
6011 copies were sent to someone. Which method to use with ::Bcc:: fields
6012 is implementation dependent, but refer to the ``Security
6013 Considerations'' section of this document for a discussion of each.*\
6016 Q5005: I used \^gv^\ 3.5.8 (\^ghostview^\) to try printing \(spec.ps)\. After every
6017 printed page, the printer ejects a blank sheet. Is this something to do
6018 with using ``letter'' rather than A4 paper?
6020 A5005: This seems to be an effect of using \^ghostview^\. Although the PostScript
6021 is generated for A4 pages, the size of the page images is such that they
6022 should fit on a letter page (they are shorter than would normally be
6023 used on A4 paper). If the PostScript file is sent directly to a
6024 PostScript printer, there is no problem. An alternative is to get hold
6025 of the \^psutils^\ toolset, which is available from
6026 \?ftp://ftp.dcs.ed.ac.uk/pub/psutils/psutils.tar.gz?\.
6027 It contains utilities for extracting pages (which can be useful for
6028 double-sided printing) and for resizing pages. If you resize from A4 to
6029 letter the text shrinks a bit, but should then be printable via
6033 Q5006: Why aren't there any man pages for Exim? I don't always carry my printed
6036 A5006: A single man page that lists the command line options is provided in
6037 file \(doc/exim.8)\ in the Exim distribution. Several other forms of
6038 online documentation are available. As well as plain ASCII text, the
6039 there are two forms - Texinfo and HTML - which have a certain amount of
6040 built-in indexing for ease of finding your way around. There are no man
6041 pages apart from the command line one because the author of Exim hasn't
6042 the time (or desire :-) to maintain yet another documentation format.
6043 Besides, it is hard to know how to split the Exim manual up.
6046 Q5007: When I send a message using the \-t-\ command line option, Exim sends only
6047 to the addresses within the message, not to those on the command line.
6049 A5007: There seems to be some confusion in the Sendmail community about the
6050 interpretation of recipient addresses on the command line if the \-t-\
6051 option is used. Some versions do one thing, and some another. Here is an
6052 except from one version of the Sendmail documentation for \-t-\:
6054 \*Read message for recipients. ::To::, ::Cc::, and ::Bcc:: lines will
6055 be scanned for recipient addresses. The ::Bcc:: line will be
6056 deleted before transmission. Any addresses in the argument
6057 list will be suppressed, that is, they will not receive
6058 copies even if listed in the message header.*\
6060 By default Exim follows this specification, and interprets addresses on
6061 the command line as addresses not to send to. You can set
6063 ==> extract_addresses_remove_arguments = false
6065 to change this behaviour so that command line addresses are added to the
6066 addresses that are taken from the header lines.
6069 Q5008: If I set up a domain list to contain //*customer.com//, it matches
6070 //customer.com// and //abc.customer.com// as required, but it also matches
6071 //noncustomer.com//, which is wrong. How can I get round this?
6073 A5008: You have to specify two entries in the list:
6075 ==> customer.com : *.customer.com
6077 because * in a domain list matches any characters, including \"."\ and
6078 including a null sequence.
6081 Q5009: I want to match all domains of the form //*.oyoy.org// but want a few
6082 exceptions. For instance I don't want //foo.oyoy.org// or //bar.oyoy.org// to be
6083 included. What is the best way to do this?
6085 A5009: Use negative items in the domain list, like this:
6087 ==> domainlist local_domains = !foo.oyoy.org : !bar.oyoy.org : *.oyoy.org
6089 If there are many exceptions, you can use a lookup instead of listing
6090 them all inline. If there are a number of exceptions that match a
6091 particular pattern, you could use a regular expression.
6094 Q5010: I can't seem to find a pre-built version of Exim anywhere. The machine
6095 is a Sparc 5 running Solaris 2.6.
6097 A5010: The primary distribution is source-only. However, some people have built
6098 and distributed RPMs and debs for Linux systems, and ports for FreeBSD.
6099 I haven't heard of anyone doing this for Solaris. The main problem with
6100 binary distributions is that there are a number of build-time options,
6101 requiring the answers to questions like:
6103 . Which DBM library do you have? (On Solaris probably ndbm, but no easy
6104 default on some other systems.)
6106 . Which uid/gid do you want to use for Exim?
6108 . Where do you want the configuration file to be? (Many different
6109 answers, even on the same OS, depending on local policy.)
6111 . Ditto for the binaries.
6113 . Which optional bits of Exim do you want to include?
6116 Q5011: Is there a version of Exim available that runs under Windows?
6118 A5011: A long time ago somebody took a copy of the Exim source with the aim of
6119 trying to port it to Windows NT. However, I never heard anything more.
6120 However, current versions of Exim can be made to run under Cygwin.
6123 Q5012: Does Exim support Delivery Status Notification (DSN), Message Status
6124 Notification (MSN), or any other form of delivery acknowledgement?
6129 Q5013: What does ``Exim'' stand for?
6131 A5013: Originally, it was ``EXperimental Internet Mailer'', which was the best I
6132 could come up with when I was starting out. At that point it was
6133 experimental - I wanted to see if the ideas I had for extending Smail's
6134 approach actually worked. Then somebody discovered about it and wanted
6135 to start using it, and told other people about it...
6138 Q5014: Although I haven't set \check_spool_space\, Exim is still checking the
6139 amount of space on the spool for incoming SMTP messages that use the
6140 SIZE option. Can I suppress this?
6142 A5014: The RFC for the SIZE option says:
6144 \*If the server currently lacks sufficient resources to accept a
6145 message of the indicated size, but may be able to accept the
6146 message at a later time, it responds with code ``452
6147 insufficient system storage''.*\
6149 and that is what Exim is trying to implement. This is entirely
6150 independent from \check_spool_space\, which says \*don't accept any mail
6151 if there is less than so much space in the spool partition*\, though the
6152 code is optimised to do both checks at the same time if required.
6153 However, you can suppress the SIZE check if you want to, by unsetting
6154 \smtp_check_spool_space\.
6157 Q5015: I just noticed log entries that start off \"<= <>"\. Am I correct in
6158 assuming that the \"<>"\ indicates that the envelope did not contain any
6161 A5015: Yes. This indicates a delivery failure report (aka a ``bounce message''),
6162 as specified in RFC 2821. The reason for using empty sender addresses is
6163 to identify bounce messages so that they themselves do not cause further
6164 bounces. Empty senders are also used for other kinds of report which
6165 should not themselves cause the generation of bounce messages. For
6166 example, Exim uses them when sending out warnings about delivery delays.
6169 Q5016: I've received a message which does not have my address in the ::To::
6170 line. It is a spam message with the same address in both the ::From:: and
6171 the ::To:: headers. How can this happen, and why doesn't Exim reject it?
6173 A5016: There is an important distinction between the ``envelope'' from and to and
6174 the ``header'' from and to. The former are sometimes called the ``sender''
6175 and ``recipient''. An email message needs an ``envelope'' for the same
6176 reason that paper mail does - the envelope tells the delivery mechanism
6177 what to do with this copy of the message, whereas the ::To:: header lists
6178 all the recipients, including those who have been sent different copies
6179 of the message because their mailbox is on some other host.
6181 An MTA such as Exim works entirely with the ``envelope'' addresses, not
6182 with those in the header lines. Don't try to block mail where envelope
6183 from and the header from differ. There are common legitimate cases where
6184 this happens, for example, messages forwarded from mailing lists and
6185 delivery failure reports.
6188 Q5017: Can (or will) Exim ever handle a message delivery purely in memory,
6189 that is, it is handled without it ever hitting the disk?
6191 A5017: It doesn't, and never will. Accepting and delivering a message are two
6192 entirely separate, independent processes, which communicate only by
6193 writing/reading the message on the disk.
6196 Q5018: If I am using dbm files for data that Exim reads, can I rebuild them
6197 on the fly, or do I need to restart Exim every time I make a change?
6199 A5018: Exim re-reads the file every time it consults it, so if you are using a
6200 cdb or a DBM library that uses just a single file (i.e. not ndbm),
6201 you can just build the new file with a temporary file name, and use
6202 \^mv^\ to rename it into the correct place on the fly. If there are two
6203 files to rename, there is a window of time during which the DBM database
6204 is inconsistent. On lightly loaded systems this may not matter.
6207 Q5019: I need an option that is the opposite of \-bpa-\, that is, a listing of
6208 those addresses generated from a top-level address that have not yet
6211 A5019: Exim does not keep this information. It saves only the top-level
6212 addresses and the list of addresses that are finished with. At each
6213 delivery attempt, generated addresses are recomputed from scratch. This
6214 makes it possible to correct errors in redirection data that is
6215 causing delivery delays. However, there is an option you can set on a
6216 \redirect\ router that changes things. It is called \one_time\, and if
6217 it is set, the list of generated addresses gets added to the top-level
6218 list at the first delivery attempt, and is never regenerated. Because
6219 top-level address lists must be real email addresses, this option cannot
6220 be used if any of the generated addresses are pipes, files, or
6224 Q5020: How can I make Exim receive incoming mail, queue it, but not attempt to
6225 deliver it? I want to be in this state while moving some mailboxes.
6227 A5020: Set \queue_only\ in the Exim configuration. Then kill your daemon,
6228 and restart it without the \-q-\ option (i.e. with just the \-bd-\ option),
6229 so that it does not spawn any queue runners. This stops all deliveries,
6230 remote as well as local.
6233 Q5021: What does Exim use for POP and IMAP as a default? Do I have to install
6236 A5021: Yes. Exim provides MTA functionality. That is, it delivers mail. POP and
6237 IMAP are two of several ways of reading previously-delivered mail. Exim
6238 does not provide that functionality. You need to install POP and/or IMAP
6239 daemons; there are several to choose from.
6242 Q5022: Is there an easy way of removing all queued messages at once in a safe
6245 A5022: Try this command:
6247 ==> exim -bp | awk '/^ *[0-9]+[mhd]/{print "exim -Mrm " $3}' | sh
6250 Q5023: Why does Exim do \*ident*\ callbacks by default? Isn't this just a waste
6251 of resources? I've been told this is an ancient way of authentication.
6254 A5023: This is a common misunderstanding, at least partially resulting from the
6255 incorrect naming of the protocol when it was first published.
6256 The service on port 113 is an identification service, which allows a
6257 target host to record information identifying the user responsible for
6258 making a connection to it. The information may not be intelligible to
6259 the recording host - it could, for example, be encrypted so that only
6260 someone on the calling host can make sense of it. It is useful for
6261 providing additional information in an audit trail.
6263 At least one site has found \^ident^\ effective against two rather
6264 prevalent kinds of open proxy (whether already blacklisted at the RBLs
6265 or not). An ACL statement is used to reject mail from servers that
6266 return \^ident^\ strings of \"squid"\ and \"CacheFlow Server"\.
6267 Snippets such as this in the RCPT ACL do the trick:
6269 ==> deny condition = ${if eq{$sender_ident}{CacheFlow Server}{1}{0}}
6270 message = Rejected - appears to be an unsecured proxy: $sender_ident
6272 The likelihood that a genuine mail process would return those specific
6273 ident strings is vanishingly small.
6275 The \^ident^\ data should not be used for authentication in any form
6276 except on a closed secure network between cooperating hosts (probably
6277 not even then). The information from the source host is only as reliable
6278 as the host itself. If it's not under your control then you have to
6279 treat the information as opaque data that can be used only by the
6280 sysadmin of the source system to trace back connection data. Some
6281 \^ident^\ implementations send out opaque cookies or DES encrypted
6282 information. \^Ident^\ is hugely useful at times - especially for
6283 checking back on connections from multiuser machines (as opposed to
6284 one-person desktop boxes).
6286 You can stop Exim making ident calls by adding
6288 ==> rfc1413_query_timeout = 0s
6290 to its configuration, but it is better to leave it active (reducing the
6291 timeout to 10s or less if it is causing problems) - it costs very
6292 little, and in cases of mail forgery from a multiuser system can track
6293 the sinner concerned very quickly.
6296 Q5024: I often have the problem that a message gets stuck in the mail queue and
6297 I want it to be bounced to a certain address.
6299 A5024: You can do this using a combination of four command line options, like
6302 ==> exim -Mf 14Fdlq-0003kM-00
6303 exim -Mmad 14Fdlq-0003kM-00
6304 exim -Mar 14Fdlq-0003kM-00 new@ddress
6305 exim -M 14Fdlq-0003kM-00
6307 The first command freezes the message so that a queue runner won't start
6308 to deliver it while you are changing things. The second command marks
6309 all existing recipients as delivered. The third command adds a new
6310 recipient, and the fourth command forces a delivery of the message,
6311 which will cause it to be delivered to the new address, and then
6315 Q5025: What precautions should I take when editing Exim's run time
6318 A5025: Edit the file and save the result in a new file. Test the syntax of
6319 the new file by running a command like this:
6321 ==> exim -bV -C exim.conf.new
6323 That will check for syntax errors without disturbing your running
6324 configuration. If you are paranoid enough, run, as \/root/\,
6326 ==> exim -C exim.conf.new <some address>
6330 and see if it delivers it. Carry on testing until happy. When happy,
6332 ==> mv exim.conf.new exim.conf
6333 kill -HUP `cat /var/spool/exim/exim-daemon.pid`
6335 Then check the Exim log to be sure the daemon restarted OK. Watch the
6336 log for a bit to see that mail is flowing.
6339 Q5026: Is exim able to use RFC 2645, \*On-demand Mail Relay*\ (ODMR)?
6344 Q5027: Is there any way I can send bounces to the postmaster, and nobody else?
6345 Basically, I want to receive them, and I don't want the reply/from
6346 person to get them. If I think they need it I will forward it myself.
6348 A5027: Put \"errors_to=postmaster"\ on every router.
6351 Q5028: When I HUP the Exim daemon, the name shown in the process table changes
6352 from \(/usr/lib/sendmail)\ (which is a symlink) to the real binary name.
6355 A5028: Add this to your Exim configuration:
6357 ==> exim_path = /usr/lib/sendmail
6360 Q5029: A message with a recipient address that contains a non-printing character
6361 is stuck on my mail queue. How can I remove this address?
6363 A5029: You can use the \-Mmd-\ command line option to mark a recipient address
6364 ``delivered'', which effectively removes it. If you are using the Bash
6365 shell, you can enter non-printing characters using an escape sequence.
6368 ==> exim -Mmd 15HKvU-00013Q-00 $'\240'abc@x.y.z
6370 In this example, the first character of the local part has a code value
6371 of 240. If you are using a shell that does not support this, create the
6372 command in a file and run it as a shell script.
6375 Q5030: I am using exim in a two queues scenario, with two different
6376 configuration files. How can I run a second copy of \^eximon^\ to
6377 inspect and modify the alternate queue?
6379 A5030: Use these commands (or put them in a script):
6381 ==> EXIMON_EXIM_CONFIG=/your/path/exim/configure.alternate
6382 export EXIMON_EXIM_CONFIG
6383 /your/path/exim/bin/eximon
6386 Q5031: Why is there no sender address on bounce messages? It shows up as "<>".
6388 A5031: See the answer to Q0042.
6391 Q5032: Are there any Exim web-based administration scripts?
6393 A5032: No (as far as is known). It seems likely that producing one that is
6394 generic enough would be a difficult task.
6397 Q5033: How can I send a copy of all outgoing messages to another mailbox?
6399 A5033: The most straightforward way is to set up a system filter, and include
6402 ==> unseen deliver mailbox@whatever.domain
6404 This sends a copy of every message to //mailbox@whatever.domain//
6405 (unless the message already has that recipient - Exim never does
6406 duplicate deliveries).
6408 To save only ``outgoing'' messages, you need to come up with a
6409 definition of what ``outgoing'' means. Typically, this might be a check
6410 on the sender address and/or on the originating host. Here is an
6413 ==> if $sender_address_domain is mydomain.com and
6414 ${mask:$sender_host_address/24} is 192.168.324.0/24
6416 unseen deliver mailbox@whatever.domain
6420 Q5034: Is there any way to make the \queue_only\ option conditional? I would
6421 like the ability to queue messages from external sources while deliver
6422 locally generated email as normal.
6424 A5034: There is no direct way of doing this. However, you can achieve the
6425 effect. In one of your ACLs that checks incoming mail from external
6428 ==> warn control = queue_only
6430 You can add other conditions as well, of course.
6433 Q5035: Does Exim run with different permissions between \-bt-\ and \-bh-\, or
6434 between verifying and actual sending?
6436 A5035: Yes. For \-bt-\ it runs as root, as it would when delivering a message.
6437 For \-bh-\, \-bv-\, and when actually receiving a message, it runs as
6444 Q9101: How can I install Exim on Mac OS X?
6446 A9101: (1) There is useful advice on this web page:
6447 \?http://www.afp548.com/Articles/Jaguar/exim410.html?\.
6449 (2) There is a package installer available at this URL:
6450 \?ftp://members.aol.com/AFP548dotcom/EximInstaller.sit?\.
6452 (3) There is another package installer for the combination of MySQL,
6453 Exim, Exiscan, CourierIMAP, and SpamAssassin at this URL:
6454 \?http://maxo.captainnet.net/installs/mail-install.html?\.
6460 Q9201: On FreeBSD, \(/usr/sbin/sendmail)\ is a symbolic link to
6461 \(/usr/sbin/mailwrapper)\; it doesn't contain the Sendmail binary. How
6462 should I replace Sendmail with Exim on FreeBSD?
6464 A9201: There is a file called \(/etc/mail/mailer.conf)\ which selects what to
6465 run for various MTA calls. Instead of changing \(/usr/sbin/sendmail)\,
6466 you should edit this file instead, to read something like this:
6468 ==> sendmail /usr/exim/bin/exim
6469 send-mail /usr/exim/bin/exim
6470 mailq /usr/exim/bin/exim -bp
6471 newaliases /usr/bin/true
6473 You probably also need to edit \(/etc/periodic.conf)\; see Q9202.
6476 Q9202: A script that FreeBSD runs nightly uses \^mailq^\ with the \-Ac-\
6477 parameter. Why doesn't Exim recognize this?
6479 A9202: \-Ac-\ is a Sendmail option that requests that mailq ``Show the mail
6480 submission queue specified in \(/etc/mail/submit.cf)\ instead of the
6481 MTA queue specified in \(/etc/mail/sendmail.cf)\''. Exim doesn't have
6482 the concept of a ``submission queue''. You can disable this feature
6483 of the nightly script by adding the line
6485 ==> daily_status_include_submit_mailq="NO" # No separate 'submit' queue
6487 to the file \(/etc/periodic.conf)\.
6490 Q9203: How can I use Exim for authenticated SMTP using Cyrus on FreeBSD?
6492 A9203: This web page may help: \?http://www.munk.nu/exim/exim-freebsd-asmtp.php?\.
6498 Q9301: I'm trying to compile on an HP machine and I don't have \^gcc^\ there. So I
6499 put \"CC=cc"\ in the \(Local/Makefile)\, but I got this error:
6501 ==> (Bundled) cc: "buildconfig.c", line 54: error 1705: Function prototypes
6502 are an ANSI feature.
6504 A9301: The bundled compiler is not an ANSI C compiler. You either have to get a
6505 copy of \^gcc^\ from the HPUX Software Porting Archives or buy the ANSI cc
6506 from HP. The advice given by one user of HP systems on the Exim
6507 mailing list was as follows:
6509 \*Personally, I wouldn't use anything but the ANSI C compiler. gcc
6510 works for compilation, but it doesn't know squat about PA-RISC chips
6511 past the 1.0 rev. Since then, HP has come out with PA-RISC 1.1, 2.0,
6512 and 2.1, each with better features. gcc will compile for them, but it
6513 doesn't produce anywhere near the optimization that HP's compiler
6516 \*I took the gcc road when we moved from FreeBSD to HP-UX because I was
6517 familiar with it. After 6 months, I had to go and re-port everything
6518 over when we realized that gcc wasn't going to do it for us long-term.
6519 If I could give advice to any new HP-UX admin: don't use gcc if you
6520 can afford the ANSI C compiler. Based on the cost of even the lowest
6521 HP workstation, that usually isn't a problem.*\
6527 Q9401: On BSDI 4.0, Exim built with Perl support exits with the error message
6529 ==> ./exim: can't load library 'libperl.so'
6531 A9401: You probably compiled perl5 yourself, without looking into
6533 ==> /usr/src/contrib/perl5/perl5.004_02/hints/bsdos.sh
6535 first. The problem is that the command
6537 ==> perl5 -MExtUtils::Embed -e ldopts
6539 doesn't give you sufficient flags to link something with libperl.
6540 Since 5.004_02 the \(hints/bsdos.sh)\ file has changed to adapt to the
6541 changes between BSDI 3.1 and 4.0, but it is still not entirely right.
6543 The solution is, when you compile perl, change the \ccdlflags\
6544 variable in config.sh to:
6546 ==> -rdynamic -Wl,-rpath,/usr/local/lib/perl5/5.00502/i386-bsdos/CORE
6548 (or something similar). Alternatively, you can run \(./Configure)\ and
6549 answering the question \*Any special flags to pass to cc to use dynamic
6550 loading?*\ with the above line. It is not known what \-rdynamic-\ means
6551 (it's not apparently documented in any man page), but that's what BSDI
6552 guys did to compile perl5 which comes with BSDI 4.0 distribution.
6558 Q9501: The IP addresses for incoming calls are all being given as
6559 255.255.255.255 or 0.0.0.0.
6561 A9501: This problem should no longer occur because a workaround has been
6568 Q9601: Exim is mysteriously crashing, usually when forking to send a delivery
6571 A9601: This has been seen in cases where Exim has been incorrectly built with
6572 a muddled combination of an \(ndbm.h)\ include file and a non-matching
6575 Faults like this have also been seen on systems with faulty motherboards.
6576 You could try to compile the Linux kernel 10 times - if the compile
6577 process stops with signal 11, your hardware is to blame.
6580 Q9602: I want to use \^logrotate^\ which is standard with RH5.2 Linux to rotate
6581 my mail logs. Anyone worked out the \^logrotate^\ config file that will
6584 A9602: Here's one suggestion:
6586 ==> /var/log/exim/main.log {
6587 create 644 exim exim
6593 The sleep is added to allow things to close the log file prior to
6594 compression. You also need similar entries for the panic log and the
6595 reject log, of course.
6598 Q9603: I'm seeing the message \*inetd[334]: imap/tcp server failing (looping),
6599 service terminated*\ on a RedHat 5.2 system, causing \^imap^\ connections to
6600 be refused. The \^imapd^\ in use is Washington Univers 12.250. Could this
6601 be anything to do with Exim?
6603 A9603: No, it's nothing to do with Exim, but here's the answer anyway: there
6604 is a maximum connection rate for \^inetd^\. If connections come in faster
6605 than that, it thinks a caller is looping. The default setting on RedHat
6606 5.2 is 40 calls in any one minute before \^inetd^\ thinks there's a problem
6607 and suspends further calls for 10 mins. This default setting is very
6608 conservative. You should probably increase it by a factor of 10 or 20.
6611 ==> imap stream tcp nowait.400 root /usr/sbin/tcpd /usr/local/etc/imapd
6613 The rate setting is the number following ``nowait''. This syntax seems to
6614 be specific to the Linux version of \^inetd^\. Other operating systems
6615 provide similar functionality, but in different ways.
6618 Q9604: I get the \*too many open files*\ error especially when a lot of messages
6619 land for Majordomo at the same time.
6621 A9604: The problem appears to be the number of open files the system can
6622 handle. This is changable by using the proc filesystem. To your
6623 \(/etc/rc.d/rc.local)\ file append something like the following:
6625 ==> # Now System is up, Modify kernel parameters for max open etc.
6627 ==> if [ -f /proc/sys/kernel/file-max ]; then
6628 echo 16384 >> /proc/sys/kernel/file-max
6630 if [ -f /proc/sys/kernel/inode-max ]; then
6631 echo 24576 >> /proc/sys/kernel/inode-max
6633 if [ -f /proc/sys/kernel/file-nr ]; then
6634 echo 2160 >> /proc/sys/kernel/file-nr
6637 By echoing the value you want for file-max to the file \(file-max)\ etc.,
6638 you actually change the kernel parameters.
6641 Q9605: I installed debian 2.2 linux on a small 325mb 486 laptop. When I try
6642 to test the Mail program, I get the following error: \*Failed to open
6643 configuration file /etc/exim.conf*\.
6645 A9605: The Debian installation should have given you \(/usr/sbin/eximconfig)\,
6646 which asks you some questions and then sets up the configuration file
6647 in \(/etc/exim.conf)\. Try running that (you'll probably need \/root/\) and see
6648 how it goes. In any case you get a thoroughly commented conf file at
6649 the end, which will give you a sample from which to work if you need
6650 further modification.
6652 The Exim docs in the Debian package are in \(/usr/doc/exim)\ where the full
6653 reference manual is \(spec.txt.gz)\.
6656 Q9606: I'm having trouble configuring Exim 4 on a Debian system. How does
6657 \(/etc/exim4/conf.d)\ work?
6659 A9606: The Debian Exim 4 package uses a quite uncommon, but elegant,
6660 method of configuration where the ``real'' Exim configuration file is
6661 assembled from a tree of snippets by a script invoked just before the
6662 daemon is started (see Q9608).
6664 This fits very well into the Debian system of configuration file
6665 management and is a great ease for the automatic configuration with
6666 Debconf. However, it is very different from the normal way Exim 4 is
6667 configured. Non-Debian users on the Exim mailing list will probably have
6668 difficulty in trying to answer specific questions about it. You may have
6669 to find a Debian expert.
6672 Q9607: I'm having difficulties trying to make Exim 4 with Redhat 9 and Berkeley
6675 A9607: Have you remembered to install the db4-devel package?
6678 Q9608: I'm running Exim 3 under Debian, and want to upgrade to Exim 4. How
6681 A9608: A user who did this, using the Debian Exim 4 package, reported as
6684 (1) The exim4 package installs easily, and the exim (3.38) package
6685 uninstalls at the same time.
6687 (2) Exim runs from \^inetd^\. Exim4 runs from \^/etc/init.d^\. Much nicer!
6689 (3) The exim conffile lives in \(/etc/exim/exim.conf)\. The exim4 conffile
6690 lives in \(/var/lib/exim4/config.autogenerated)\. It is, as the name
6691 suggests, autogenerated.
6693 (4) A new directory is created called \(/etc/exim4)\. This contains the
6694 conffiles to generate the above config. You make changes here.
6696 (5) Once you have made changes to the files in \(/etc/exim4)\ you run the
6697 script \^update-exim4.conf^\ which generates a replacement
6698 \(config.autogenerated)\.
6700 [Added comment by the Debian maintainer, slightly edited:
6701 You also need to tell the Exim daemon to reread the changed
6702 configuration. You can do this using SIGHUP by hand. Alternatively,
6703 instead of running \^update-exim4.conf^\ you can use
6705 ==> invoke-rc.d exim4 reload
6707 which does the rebuild and also tells Exim to reread the changed
6710 (6) In my experience, you need to carefully check the generated
6711 configs. eg, it did not generate a system filter file reference in the
6712 \(config.autogenerated)\. I didn't bother too much, since this is a home
6715 (7) All of this may be in the docs. I've read some of them, obviously,
6716 but didn't come across an actual upgrade guide.
6718 [The Debian maintainer says:
6719 \(/usr/share/doc/exim4-base/README.Debian.gz)\ and \^update-exim4.conf(8)^\
6720 should answer most of the questions.]
6722 (8) I've still got some minor things to tweak to get back to where I
6723 was before with Exim 3. But overall, it's no drama.
6726 Q9609: Why do some servers refuse SMTP connections from my Linux box, but accept
6727 connections from hosts running other operating systems?
6729 A9609: If you are sure this isn't a policy issue (that is, your box isn't
6730 administratively blocked for some reason), this may be because your
6731 Linux box has ECN (Explicit Congestion Notification) enabled in its
6732 TCP/IP stack. There are many broken firewalls that refuse connections
6733 from ECN-enabled hosts. You can check the state of your box by running
6735 ==> cat /proc/sys/net/ipv4/tcp_ecn
6737 If the value is "1", you have ECN enabled. You can turn it off by
6738 running this command:
6740 ==> echo "0" > /proc/sys/net/ipv4/tcp_ecn
6746 Q9701: Exim builds fine with \^gcc^\ on SunOS 4 but crashes inside \^^sscanf()^^\.
6748 A9701: Make sure you are linking with the GNU \^ld^\ linker and not the system
6752 Q9702: How can I get rid of spurious \"^M"\ (carriage return) characters in
6753 messages sent from CDE \^dtmail^\?
6755 A9702: CDE \^dtmail^\ passes messages to Exim via the command line interface with
6756 lines terminated by CRLF, instead of the Unix convention of just LF.
6757 This should not be a problem if you are using Exim release 4.21 or
6758 later, as changes were made to detect CRLF line endings.
6760 In earlier versions of Exim, CR would be treated as just another data
6761 character. There was, however, a command line option called
6762 \-dropcr-\ which caused Exim to ignore all CR characters in an incoming
6763 non-SMTP message. (This option is a no-op in current releases.)
6765 If you are using a pre-4.21 version of Exim, you should configure
6766 \^dtmail^\ to add this option to the command it uses to call Exim (using
6767 the path \(/usr/lib/sendmail)\). However, it has been reported that it
6768 isn't possible to change this call from \^dtmail^\ by any official
6769 means. An alternative approach is to replace \(/usr/lib/sendmail)\ by a
6770 filtering script that removes the spurious CRs from the input before
6774 Q9703: On SunOS 4 Exim crashes when looking up domains in the DNS that have
6775 more than 10 A records.
6777 A9703: There are Sun library patches to fix this. It is not Exim's problem.
6778 For 4.13_U1 the patch is 101558-xx; for 4.1.3 the patch is 100891-xx.
6779 From the README: \*1054748 ftp, ping dump core when connecting to a host
6780 with multiple DNS A records.*\ An alternative is to build another
6781 resolver library - such as the ones that are part of the \^bind^\
6782 distribution - and explicitly link against those.
6785 Q9704: I am experiencing mailbox locking problems with Sun's \^mailtool^\ used
6788 A9704: Under the \"Expert"\ settings of \^mailtool^\ is a option to turn on \*Use
6789 network aware mail file locking*\. By default \^dtmail^\ has this set, but
6790 \^mailtool^\ doesn't. You should set it. The help info on \^dtmail^\ has this
6793 \*Mailer tries to prevent two different instances of itself from opening
6794 the same mail file at the same time through a technique that detects
6795 this access when both instances of Mailer and the file are all on the
6796 same machine. A network-aware mail file locking protocol is available
6797 that uses ToolTalk to coordinate instances of Mailer running from more
6798 than one machine, or mail files accessed over the network. Mailer can
6799 only change this option when first opening a mail file.*\
6801 If you are using the SunOS4 version of \^mailtool^\, this apparently
6802 doesn't work. The only thing which does seem to work it getting the user
6803 to hit the \"done"\ button to make it release the lock.
6806 Q9705: Exim has been crashing on my Solaris x86 system, apparently while
6807 running DBM functions.
6809 A9705: The use of \^ndbm^\ with \^gcc^\ has caused problems on x86 Solaris systems.
6810 Try changing one or the other; using either DB with gcc, or Sun's
6811 WS compiler with \^ndbm^\, has fixed this in the past.
6814 Q9706: The \^exiwhat^\ utility isn't working for me on a Solaris 2 system.
6816 A9706: Have you got \(/usr/ucb)\ on your path? If so, it is probably picking up the
6817 wrong version of the \^ps^\ command. The \^exiwhat^\ script is built on
6818 Solaris to expect the normal Solaris version of \^ps^\.
6821 Q9707: How do I stop Sun's \^dtcm^\ from hanging?
6823 A9707: From qmail's FAQ: \*There is a novice programming error in dtcm, known as
6824 ``failure to close the output side of the pipe in the child.'' Sun has,
6825 at the time of this writing, not yet provided a patch.*\
6828 Q9708: I want Exim to use only the resolver (i.e. ignore \(/etc/hosts)\), but don't
6829 want to alter the \(nsswitch.conf)\ file in Solaris 2.
6831 A9708: You need to rebuild Exim after fiddling with \(OS/os.h-SunOS5)\:
6833 ==> #define gethostbyaddr res_gethostbyaddr
6834 #define gethostbyname res_gethostbyname
6835 #define endhostent res_endhostent
6836 #define endnetent res_endnetent
6837 #define gethostent res_gethostent
6838 #define getnetbyaddr res_getnetbyaddr
6839 #define getnetbyname res_getnetbyname
6840 #define getnetent res_getnetent
6841 #define sethostent res_sethostent
6842 #define setnetent res_setnetent
6844 Note that \-lnsl-\ is still needed in the Makefile as it
6845 contains code used by the NIS lookup and also the \^^inet_addr()^^\ function
6849 Q9709: When I try to compile Exim 4.x on Solaris 2.5.1 I get an error along the
6850 lines of \*no such field in struct as 'value.ui32'*\.
6852 A9709: Look in the Exim file \(OS/os.h-SunOS5.h)\ for the line
6854 ==> #define LOAD_AVG_FIELD value.ui32
6856 and change \"ui32"\ to \"ul"\ (that's u followed by the letter ell, not
6857 the digit one). Solaris 2.5.1 is getting very old now...
6861 98. CONFIGURATION COOKBOOK
6863 Q9801: How do I configure Exim as part of TPC (\?http://www.tpc.int?\)?
6865 A9801: Suppose you want to accept faxes destined for 1(801)539-*. These are
6866 addressed to the domain //9.3.5.1.0.8.1.tpc.int//. Set up a transport to
6867 handle the delivery:
6871 command = /usr/local/tpc/tpcmailer.pl $local_part@$domain \
6875 \(/usr/local/tpc/tpcmailer.pl)\ is the mail processing script that can
6876 be obtained from the TPC distribution. Create a router to route mail
6877 for the TPC domain to that transport. This must be placed before your
6883 domains = *.9.3.5.1.0.8.1.tpc.int
6885 Of course, there are other things to do as well before your system is
6886 a functioning TPC server.
6889 Q9802: How do I configure Exim so that it sends mail to the outside world only
6890 from a restricted list of our local users?
6892 A9802: You will need to have a convenient way of checking the list. If it is
6893 only a handful of users, you could just list them inline. Otherwise, you
6894 need to put them in a file or database. Let's suppose you've just got a
6895 list in a file. Put this as your first router:
6899 domains = ! +local_domains
6900 senders = ! : ! lsearch;/etc/permitted/senders
6902 data = :fail: you are not allowed to send outside
6904 The senders should be listed as complete addresses, with both a local
6905 part and a domain. For a large list, use a DBM or cdb file instead, or
6906 a database. The first item in the \senders\ list is empty, to match the
6907 empty sender. This is necessary because bounce messages have null
6911 Q9803: A site for which I provide secondary MX is down for some time. Is there
6912 a way to run the queue for that destination separately from the main
6915 A9803: No, because Exim does not have the concept of ``the queue for that
6916 destination''. It simply has a single pool of messages awaiting delivery
6917 (and some of them may have several destinations). The best approach to
6918 this is to arrange for all messages for the site to be saved somewhere
6919 other than the main spool, either on a separate dedicated MTA, or in
6923 Q9804: We want to be able to temporarily lock out a user by disabling the
6924 password and moving the home directory to another place. How can we
6925 arrange to reject mail for users in this state?
6927 A9804: Change the home directory pointer in the passwd file to something
6928 distinctive. For example, we use \(/home/CANCELLED)\ for cancelled users.
6929 Then you can pick up such users with this router, which is placed
6930 immediately after \%system_aliases%\:
6932 ==> cancelled_users:
6935 condition = ${if eq {$home}{/home/CANCELLED}{yes}{no}}
6937 data = :fail: this account is cancelled
6940 Q9805: How can I configure Exim so that all mails addressed to
6941 //something@username.domain.net// get delivered to
6942 \(/var/spool/mail/username)\?
6944 A9805: Assuming that you have set up //username// as a normal user, with
6945 conventional routing for //username@domain.net// to that mailbox, all
6946 you need to do is set up a redirection, using a router like this:
6950 data = ${if match{$domain}{\N^(.*)\.domain\.net$\N}\
6951 {$1}fail}@domain.net
6953 If you set \envelope_to\ in the \%appendfile%\ transport, the original
6954 envelope address is preserved in the message in an ::Envelope-to::
6958 Q9806: How do I get exim not to add a ::Sender:: header to locally originated
6961 A9806: It adds it only if the ::From:: header doesn't correspond to the user
6962 sending the message. You can suppress this by setting
6963 \no_local_from_check\. If your real question is \*How do I submit mail
6964 from UUCP without it adding ::Sender::?*\, see Q1503.
6967 Q9807: Is there any way to have messages sent to a specific local address
6968 delayed by - say - 24 hours?
6970 A9807: Set up a router like this:
6974 domains = the.domain
6975 local_parts = thelocalpart
6976 condition = ${if < {$message_age}{86400}{yes}{no}}
6978 data = :defer: message not old enough
6981 Of course, this will also have the effect of setting a retry time for
6982 the address. You may want to set a special retry rule for it. Note the
6983 use of \no_verify\ to ensure that this router is not used when Exim is
6984 verifying addresses.
6987 Q9808: I have a mailing list exploder on one host, and three other hosts where
6988 I want to do the actual deliveries from. How can I get Exim to split
6989 a message into groups of recipients between the three hosts?
6991 A9808: Set up a router that routes all remote addresses to a specific
6992 transport, with a list of your three hosts. For example:
6995 driver = manualroute
6996 transport = to_three_smtp
6997 route_list = !+local_domains hostA:hostB:hostC
6999 The transport looks like this:
7005 By setting \hosts_randomize\, you request that the host list be sorted
7006 randomly each time the transport is called, in order to spread the load.
7007 The number of times the transport is called for each message depends on
7008 the setting of the global option \remote_max_parallel\. If it is set to
7009 1, the transport is called only once for each message, so only one host
7010 is used, but different messages use different hosts because of the
7013 The \max_rcpt\ option (default 100) controls the number of addresses
7014 sent in each copy of the message - several copies are sent over the
7015 same connection if necessary.
7017 If you want individual messages to be split between the three hosts, you
7018 must set the global option \remote_max_parallel\ to 3. This allows Exim
7019 to run 3 separate instances of the transport at once. It will pass
7020 one-third of all the addresses to each instance. Because the host list
7021 is randomized, not round-robinned, there is no guarantee that a single
7022 message will use all three hosts, but on average it should.
7025 Q9809: Can I configure Exim so that my gateway host sends a copy of each
7026 incoming message to each of two internal hosts?
7028 A9809: The easiest way to do this is to make use of the \unseen\ router option,
7029 and set up two separate routers. You need to be able to identify
7030 incoming messages somehow. Typically this can be done by testing the
7031 domain of the recipient address, in which case the configuration should
7032 contain something like this:
7035 driver = manualroute
7036 domains = ! *.your.domain.example
7037 route_data = * host1.your.domain.example
7038 transport = remote_smtp
7042 driver = manualroute
7043 domains = ! *.your.domain.example
7044 route_data = * host2.your.domain.example
7045 transport = remote_smtp
7047 The \unseen\ setting on \%r1%\ means that after it has accepted an
7048 address, the address is also passed on to \%r2%\, and so two deliveries
7052 Q9810: How can I implement ``SMTP-after-POP'' with Exim?
7057 Q9811: I would like to ``tap off'' a proportion of real mail traffic from my
7058 live mail server to use in tests of a new server. I want to preserve the
7059 envelope contents, but to suppress any error notifications to the
7065 Q9812: How can I lookup data from a single file using both single IP addresses
7066 and IP address blocks as keys? I want to set \smtp_accept_max_per_host\
7067 by this means, and also include a default.
7069 A9812: You cannot do this in a single lookup, because you need separate lookups
7070 for individual addresses and address blocks. However, these lookups can
7071 be nested in a single expansion string. For example, suppose you are
7072 using an lsearch file with entries like this:
7074 ==> 192.168.34.35: 4
7078 You can use this setting:
7080 ==> smtp_accept_max_per_host = \
7081 ${lookup{$sender_host_address}lsearch{/path/to/file}\
7084 ${lookup{${mask:$sender_host_address/24}}lsearch*{/path/to/file}}\
7087 Note that the first lookup does not have an asterisk on the search
7088 type. If you have blocks of different sizes (/24, /26, etc) you have to
7089 configure it to do a separate lookup for each size, with just the final
7090 one using a default.
7094 99. LIST OF SAMPLE CONFIGURATIONS
7096 As well as being hyperlinked from the HTML version of this document, each
7097 sample configuration is also available as a file in the \(config.samples)\
7098 directory, which can be independently downloaded.
7100 Samples whose names are of the form Cnnn are Exim configurations; those with
7101 names of the form Fnnn are filter file fragments; those with names of the form
7102 Lnnn are sample \^^local_scan()^^\ functions, and those with names of thf form
7103 Snnn are scripts of various kinds. There are other examples of
7104 \^^local_scan()^^\ functions at a number of web sites (for example,
7105 \?http://marc.merlins.org/linux/exim/sa.html?\).
7107 There are gaps in the C and F numbers because I have omitted the Exim 3 samples
7108 that have not been converted for Exim 4.
7110 C002: ``Although exim not intended for use in UUCP environment (it doesn't
7111 know anything about bang!path addresses), I'm successfully using it for
7112 delivering mail to UUCP clients.''
7114 C006: ``This is how I have configured a PP-inspired vacationnote, there is
7115 (was?) such a feature in PP. The user makes a file \(tripnote)\ in his/her
7116 home directory, the message is passed to the sender once with a short
7119 C022: ``This is the Exim configuration file of a machine which delivers mail to
7120 several local domains where the mail is delivered locally, several hairy
7121 domains, handled as described below, and a half-virtual domain, which is
7122 first processed by its special alias file, then processed as other local
7123 domains (including the processing by the global alias file).''
7125 C037: An elegant way of using ETRN, which does immediate delivery if the host
7126 is online, but saves mail in a BSMTP file after some time on the queue.
7127 ETRN then re-injects the mail.
7129 C042: ``Since the Exim 4 configuration needed to get Mailman to work differs a
7130 little bit from Exim 3 and since I still haven't seen a recipe for
7131 Mailman with Exim 4, I'm providing my configuration (based heavily on
7132 \?http://www.exim.org/howto/mailman.html?\).''
7134 C043: ``Attached is an Exim 4 config file which is designed for an Exim server
7135 that is put in front of an Exchange 5.5 system but which verifies the
7136 valid addresses that are stored in Exchange via LDAP lookups against the
7139 C044: ``I thought I'd submit this as an example of an authenticated mail hub
7140 configuration. Several people have asked for it so I thought it
7141 might be of interest.''
7143 C045: ``Here it is, for Exim 4.10 and Cyrus IMAPD 2.1.5 using db3/db4-format
7144 mailbox database. This configuration delivers the messages to Cyrus
7145 IMAPD using LMTP over a TCP/IP socket.''
7147 C046: ``Deliver a duplicate of some proportion of all messages to a special
7148 machine specified in the file \(/MAIL_TAP_HOST)\, if it exists.''
7150 C047: A sample configuration for calling Spamassassin directly from Exim.
7152 C049: ``I've been seeing a whole bunch of IPs that send me spam or virus mail
7153 and HELOing as one of my own IPs, or as HELO one.of.my.own.domains (or
7154 maybe HELO \primary_hostname\).''
7156 C050: A configuration that uses the DNS to implement virtual domains.
7158 C051: ``I've been working quite hard to come up with a config that reasonably
7159 matches the qmail-ldap setup, without the warts.''
7161 F001: ``I thought that the rest of the list may be interested in reviewing our
7162 filter as a starting point for their own system message filter.''
7164 F002: ``... program which refused mail from unknown addresses until they mailed
7165 me promising not to spam me ... since I'd already thought through how
7166 to do it in Exim, and knew it'd be slightly easier than falling out of
7167 bed, I went ahead and did it.''
7169 F003: ``Here's four checks installed in our system wide filter that knock out
7170 a lot of otherwise hard to detect rubbish.''
7172 F004: ``This is an Exim filter snippet to change locally-generated ::Message-Id::
7173 and ::Resent-Message-Id:: headers to world-unique values.''
7175 L001: A \^^local_scan()^^\ function for Exim that calls \^uvscan^\.
7177 S001: A Perl script for patching the name of the configuration file in an
7180 S002: ``When I moved from smail to exim I built a program that took individual
7181 config pieces, stripped all the comments, and built a config file.''
7183 *** End of Exim FAQ ***
git://git.exim.org / users / heiko / exim.git / blob