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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 4.00 and later releases. It has been
48 extensively revised, and material that was relevant only to earlier releases
49 has been removed. As this caused some whole sections to disappear, I've taken
50 the opportunity to re-arrange the sections and renumber everything except the
51 configuration samples.
53 References of the form Cnnn, Fnnn, Lnnn, and Snnn are to the sample
54 configuration, filter, \^^local_scan()^^\, and ``useful script'' files. These
55 are hyperlinked from the HTML version of this FAQ. They can also be found in
56 the separately distributed directory called \(config.samples)\. The primary
59 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4/config.samples.tar.gz?\
60 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4/config.samples.tar.bz2?\
62 There are brief descriptions of these files at the end of this document.
65 Last update: 31-March-2004
68 The FAQ is divided into the following sections:
71 1. Building and Installing
73 3. Routing to remote hosts
74 4. Routing for local delivery
78 8. Rewriting addresses
86 16. Modifying message bodies
87 17. Encryption (TLS/SSL)
97 98. Configuration cookbook
98 99. List of sample configurations
104 Q0001: Exim is crashing. What is wrong?
106 A0001: Exim should never crash. The author is always keen to know about
107 crashes, so that they can be diagnosed and fixed. However, before you
108 start sending me email, please check that you are running the latest
109 release of Exim, in case the problem has already been fixed. The
110 techniques described below can also be useful in trying to pin down
111 exactly which circumstances caused the crash and what Exim was trying to
112 do at the time. If the crash is reproducable (by a particular message,
113 say) keep a copy of that message.
116 Q0002: Exim is not working. What is wrong? How can I check what it is doing?
118 A0002: Exactly how is it not working? Check the more specific questions in the
119 other sections of this FAQ. Some general techniques for debugging are:
121 (1) Look for information in Exim's log files. These are in the \(log)\
122 directory in Exim's spool directory, unless you have configured a
123 different path for them. Serious operational problems are reported
126 (2) If the problem involves the delivery of one or more messages, try
127 forcing a delivery with the \-M-\ option and also set the \-d-\
128 option, to cause Exim to output debugging information. For example:
130 ==> exim -d -M 0z6CXU-0005RR-00
132 The output is written to the standard error stream. You need to have
133 admin privileges to use \-M-\ and \-d-\.
135 (3) If the problem involves incoming SMTP mail, try using the \-bh-\
136 option to simulate an incoming connection from a specific host,
139 ==> exim -bh 10.9.8.7
141 This goes through the motions of an SMTP session, without actually
142 accepting a message. Information about various policy checks is
143 output. You will need to know how to pretend to be an SMTP client.
145 (4) If the problem involves lack of recognition or incorrect handling
146 of local addresses, try using the \-bt-\ option with debugging turned
147 on, to see how Exim is handling the address. For example,
149 ==> exim -d -bt z6abc
151 shows you how it would handle the local part \"z6abc"\.
154 Q0003: What does the error \*Child process of address_pipe transport returned
155 69 from command xxx*\ mean?
157 A0003: It means that when a transport called \%address_pipe%\ was run to pass an
158 email message by means of a pipe to another process running the command
159 xxx, the return code from that command was 69, which indicates some kind
160 of error (the success return code is 0).
162 The most common meaning of exit code 69 is ``unavailable'', and this often
163 means that when Exim tried to run the command \(xxx)\, it failed. One
164 cause of this might be incorrect permissions on the file containing the
165 command. See also Q0026.
168 Q0004: My virtual domain setup isn't working. How can I debug it?
170 A0004: You can use an exim command with \-d-\ to get it to show you how it is
171 processing addresses. You don't actually need to send a message; use the
172 \-bt-\ option like this:
174 ==> exim -d -bt localpart@virtualhost
176 This will show you which routers it is using. If the problem appears
177 to be with the expansion of an option setting, you can use the
178 \debug_print\ option on a router to get Exim to output the expanded
179 string values as it goes along.
182 Q0005: Why is Exim not rejecting incoming messages addressed to non-existent
185 A0005: This is controlled by the ACL that is run for each incoming RCPT
186 command. It is defined by the \acl_smtp_rcpt\ option. You can check this
187 part of your configuration by using the \-bh-\ option to run a simulated
188 SMTP session, during which Exim will tell you what things it is
192 Q0006: I've put an entry for \"*.my.domain"\ in a DBM lookup file, but it isn't
195 A0006: You need to request ``partial matching'' by setting the search type to
196 \partial-dbm\ in order for this to work.
199 Q0007: I've put the entry \"*@domain.com"\ in a lookup database, but it isn't
200 working. The expansion I'm using is:
202 ==> ${lookup{${lc:$sender_address}}dbm{/the/file} ...
204 A0007: As no sender address will ever be //*@domain.com// this will indeed have
205 no effect as it stands. You need to tell Exim that you want it to look
206 for defaults after the normal lookup has failed. In this case, change the
207 search type from \"dbm"\ to \"dbm*@"\. See the section on \*Default values in
208 single-key lookups*\ in the chapter entitled \*File and database
209 lookups*\ in the Exim manual.
212 Q0008: If I run \"./exim -d -bt user@domain"\ all seems well, but when I send
213 a message from my User Agent, it does not arrive at its destination.
215 A0008: Try sending a message directly to Exim by typing this:
217 ==> exim -v user@domain
218 <some message, could be empty>
221 If the message gets delivered to a remote host, but never arrives at its
222 final destination, then the problem is at the remote host. If, however,
223 the message gets through correctly, then the problem may be between your
224 User Agent and Exim. Try setting Exim's \log_selector\ option to include
225 \"+arguments"\, to see with which arguments the UA is calling Exim.
228 Q0009: What does \*no immediate delivery: too many messages received in one SMTP
231 A0009: An SMTP client may send any number of messages down a single SMTP
232 connection to a server. Initially, an Exim server starts up a delivery
233 process as soon as a message is received. However, in order not to start
234 up too many processes when lots of messages are arriving (typically
235 after a period of downtime), it stops doing immediate delivery after a
236 certain number of messages have arrived down the same connection. The
237 threshold is set by \smtp_accept_queue_per_connection\, and the default
238 value is 10. On large systems, the value should be increased. If you are
239 running a dial-in host and expecting to get all your mail down a single
240 SMTP connection, then you can disable the limit altogether by setting
244 Q0010: Exim puts \*for \[address]\*\ in the ::Received:: headers of some, but not all,
245 messages. Is this a bug?
247 A0010: No. It is deliberate. Exim inserts a ``for'' phrase only if the incoming
248 message has precisely one recipient. If there is more than one
249 recipient, nothing is inserted. The reason for this is that not all
250 recipients appear in the ::To:: or ::Cc:: headers, and it is considered a
251 breach of privacy to expose such recipients to the others. A common
252 case is when a message has come from a mailing list.
255 Q0011: Instead of \^exim_dbmbuild^\, I'm using a homegrown program to build DBM
256 (or cdb) files, but Exim doesn't seem to be able to use them.
258 A0011: Exim expects there to be a binary zero value on the end of each key used
259 in a DBM file if you use the \"dbm"\ lookup type, but not for the \"dbmnz"\
260 lookup type or for the keys of a cdb file. Check that you haven't
261 slipped up in this regard.
264 Q0012: Exim is unable to route to any remote domains. It doesn't seen to be
265 able to access the DNS.
267 A0012: Try running \"exim -d+resolver -bt \[remote address]\"\. The \-d-\
268 options turns on debugging output, and the addition of \"+resolver"\
269 will make it show the resolver queries it is building and the results of
270 its DNS queries. If it appears unable to contact any name servers, check
271 the contents and permissions of \(/etc/resolv.conf)\.
274 Q0013: What does the error message \*transport system_aliases: cannot find
275 transport driver "redirect" in line 92*\ mean?
277 A0013: \%redirect%\ is a router, not a transport. You have put a configuration
278 for a router into the transports section of the configuration file.
281 Q0014: Exim is timing out after receiving and responding to the DATA command
282 from one particular host, and yet the client host also claims to be
283 timing out. This seems to affect only certain messages.
285 A0014: This kind of problem can have many different causes.
287 (1) This problem has been seen with a network that was dropping all
288 packets over a certain size, which mean that the first part of the SMTP
289 transaction worked, but when the body of a large message started
290 flowing, the main data bits never got through the network. See also
293 (2) This can also happen if a host has a broken TCP stack and won't
294 reassemble fragmented datagrams.
296 (3) A very few ISDN lines have been seen which failed when certain data
297 patterns were sent through them, and replacing the routers at both end
298 of the link did not fix things. One of them was triggered by more than 4
299 X's in a row in the data.
302 Q0015: What does the message \*Socket bind() to port 25 for address (any)
303 failed: address already in use*\ mean?
305 A0015: You are trying to run an Exim daemon when there is one already running -
306 or maybe some other MTA is running, or perhaps you have an SMTP line in
307 \(/etc/inetd.conf)\ which is causing \(inetd)\ to listen on port 25.
310 Q0016: I've set \"verify = header_syntax"\ in my ACL, but this causes Exim to
311 complain about header lines like \"To: Work: Jim <jims@email>,
312 Home: Bob <bobs@email>"\ which look all right to me. Is this a bug?
314 A0016: No. Header lines such as ::From::, ::To::, etc., which contain addresses, are
315 structured, and have to be in a specific format which is defined in RFC
316 2822. Unquoted colons are not allowed in the ``phrase'' part of an email
317 address (they are OK in other headers such as ::Subject::). The correct
318 form for that header is
320 ==> To: "Work: Jim" <jims@email>, "Home: Bob" <bobs@email>
322 You will sometimes see unquoted colons in ::To:: and ::Cc:: headers, but only
323 in connection with name lists (called ``groups''), for example:
325 ==> To: My friends: X <x@y.x>, Y <y@w.z>;,
326 My enemies: A <a@b.c>, B <b@c.d>;
328 Each list must be terminated by a semicolon, as shown.
331 Q0017: Whenever Exim tries to deliver a specific message to a particular
332 server, it fails, giving the error \*Remote end closed connection after
333 data*\ or \*Broken pipe*\ or a timeout. What's going on?
335 A0017: \*Broken pipe*\ is the error you get on some OS when the remote host just
336 drops the connection. The alternative is \*connection reset by peer*\.
337 There are many potential causes. Here are some of them (see also Q0068):
339 (1) There are some firewalls that fall over on binary zero characters
340 in email. Have a look, e.g. with \"hexdump -c mymail | tail"\ to see if
341 your mail contains any binary zero characters.
343 (2) There are broken SMTP servers around that just drop the connection
344 after the data has been sent if they don't like the message for some
345 reason (e.g. it is too big) instead of sending a 5xx error code. Have
346 you tried sending a small message to the same address?
348 It has been reported that some releases of Novell servers running NIMS
349 are unable to handle lines longer than 1024 characters, and just close
350 the connection. This is an example of this behaviour.
352 (3) If the problem occurs right at the start of the mail, then it could
353 be a network problem with mishandling of large packets. Many emails are
354 small and thus appear to propagate correctly, but big emails will
355 generate big IP datagrams.
357 There have been problems when something in the middle of the network
358 mishandles large packets due to IP tunnelling. In a tunnelled link, your
359 IP datagrams gets wrapped in a larger datagram and sent over a network.
360 This is how virtual private networks (VPNs), and some ISP transit
361 circuits work. Since the datagrams going over the tunnel require a
362 larger packet size, the tunnel needs a bigger maximum transfer unit
363 (MTU) in the network handling the tunnelled packets. However, MTUs
364 are often fixed, so the tunnel will try to fragment the packets.
366 If the systems outside the tunnel are using path MTU discovery, (most
367 Sun Sparc Solaris machines do by default), and set the DF (don't
368 fragment) bit because they don't send packets larger than their \(local)\
369 MTU, then ICMP control messages will be sent by the routers at the
370 ends of the tunnel to tell them to reduce their MTU, since the tunnel
371 can't fragment the data, and has to throw it away. If this mechanism
372 stops working, e.g. a firewall blocks ICMP, then your host never
373 knows it has hit the maximum path MTU, but it has received no ACK on
374 the packet either, so it continues to resend the same packet and the
375 connection stalls, eventually timing out.
377 You can test the link using pings of large packets and see what works:
379 ==> ping -s host 2048
381 Try reducing the MTU on the sending host:
383 ==> ifconfig le0 mtu 1300
385 Alternatively, you can reduce the size of the buffer Exim uses for SMTP
386 output by putting something like
388 ==> DELIVER_OUT_BUFFER_SIZE=512
390 in your \(Local/Makefile)\ and rebuilding Exim (the default is 8192).
391 While this should not in principle have any effect on the size of
392 packets sent, in practice it does seem to have an effect on some OS.
394 You can also try disabling path MTU discovery on the sending host. On
397 ==> echo 1 >/proc/sys/net/ipv4/ip_no_pmtu_disc
399 For a general discussion and information about other operating systems, see
400 \?http://www.netheaven.com/pmtu.html?\. If disabling path MTU discovery
401 fixes the problem, try to find the broken or misconfigured
402 router/firewall that swallows the ICMP-unreachable packets. Increasing
403 timeouts on the receiving host will not work around the problem.
406 Q0018: Why do messages not get delivered down the same connection when I do
407 something like: \"exim -v -R @aol.com"\? For other domains, I do this and
408 I see the appropriate \*waiting for passed connections to get used*\
411 A0018: Recall that Exim does not keep separate queues for each domain, but
412 operates in a distributed fashion. Messages get into its `waiting for
413 host x' hints database only when a delivery has been tried, and has had
414 a temporary error. Here are some possibilities:
416 (1) The messages to \(aol.com)\ got put in your queue, but no previous
417 delivery attempt occured before you did the \-R-\. This might have been
418 because of your settings of \queue_only_load\, \smtp_accept_queue\, or any
419 other option that caused no immediate delivery attempt on arrival. If
420 this is the case, you can try using \-qqR-\ instead of \-R-\.
422 (2) You have set \connection_max_messages\ on the smtp transport, and
423 that limit was reached. This would show as a sequence of messages
424 down one connection, then another sequence down a new connection, etc.
426 (3) Exim tried to pass on the SMTP connection to another message, but
427 that message was in the process of being delivered to \(aol.com)\ by some
428 other process (typically, a normal queue runner). This will break the
429 sequence, though the other delivery should pass its connection on to
430 other messages if there are any.
432 (4) The folk at \(aol.com)\ changed the MX records so the host names have
433 changed - or a new host has been added. I don't know how likely this is.
435 (5) Exim is not performing as it should in this regard, for some reason.
436 Next time you have mail queued up for \(aol.com)\, try running
438 ==> exim_dumpdb /var/spool/exim wait-remote_smtp
440 to see if those messages are listed among those waiting for the relevant
444 Q0019: There seems to be a problem in the string expansion code: it doesn't
445 recognize references to headers such as \"${h_to}"\.
447 A0019: The only valid syntax for header references is (for example) \"$h_to:"\
448 because header names are permitted by RFC 2822 to contain a very wide
449 range of characters. A colon (or white space) is required as the
453 Q0020: Why do connections to my machine's SMTP port take a long time to respond
454 with the banner, when connections to other ports respond instantly? The
455 delay is sometimes as long as 30 seconds.
457 A0020: These kinds of delay are usually caused by some kind of network problem
458 that affects outgoing calls made by Exim at the start of an incoming
459 connection. Configuration options that cause outgoing calls are:
461 (1) \rfc1413_hosts\ and \rfc1413_query_timeout\ (for \*ident*\ calls).
462 Firewalls sometimes block ident connections so that they time out,
463 instead of refusing them immediately. This can cause this problem.
464 See Q5023 for a discussion of the usefulness of \*ident*\.
466 (2) The \host_lookup\ option, the \host_reject_connection\ option, or a
467 condition in the ACL that runs at connection time requires the
468 remote host's name to be looked up from its IP address. Sometimes
469 these DNS lookups time out. You can get this effect with ACL
470 statements like this:
472 ==> deny hosts = *.x.example
474 If at all possible, you should use IP addresses instead of host
475 names in blocking lists in order to to avoid this problem.
477 You can use the \-bh-\ option to get more information about what is
478 happening at the start of a connection. However, note that the \-bh-\
479 option does not provide a complete simulation. In particular, no
480 \*ident*\ checks are done, so it won't show up a delay problem that is
481 related to (1) above.
484 Q0021: What does \*failed to create child process to send failure message*\ mean?
485 This is a busy mail server with \smtp_accept_max\ set to 500, but this
486 problem started to occur at about 300 incoming connections.
488 A0021: Some message delivery failed, and when Exim wanted to send a bounce
489 message, it was unable to create a process in which to do so. Probably
490 the limit on the maximum number of simultaneously active processes has
491 been reached. Most OS have some means of increasing this limit, and in
492 some operating systems there is also a limit per uid which can be
496 Q0022: What does \*No transport set by system filter*\ in a log line mean?
498 A0022: Your system filter contains a \"pipe"\ or \"save"\ or \"mail"\ command,
499 but you have not set the corresponding option which specifies which
500 transport is to be used. You need to set whichever of
501 \system_filter_pipe_transport\, \system_filter_file_transport\ or
502 \system_filter_reply_transport\ is relevant.
505 Q0023: Why is Exim refusing to relay, saying \*failed to find host name from IP
506 address*\ when I have the sender's IP address in an ACL condition? My
507 configuration contains this ACL statement:
509 ==> accept hosts = lsearch;/etc/mail/relaydomains:192.168.96.0/24
511 A0023: When checking a host list, the items are tested in left-to-right
512 order. The first item in your list is a lookup on the incoming host's
513 name, so Exim has to determine the name from the incoming IP address in
514 order to perform the test. If it can't find the host name, it can't do
515 the check, so it gives up. You would have discovered what was going
516 on if you had run a test such as
518 ==> exim -bh 192.168.96.131
520 The solution is to put all explicit IP addresses first in the list.
521 Alternatively, you can split the ACL statement into two like this:
523 ==> accept hosts = lsearch;/etc/mail/relaydomains
524 accept hosts = 192.168.96.0/24
526 If the host lookup fails, the first \"accept"\ fails, but then the
527 second one is considered.
530 Q0024: When I run \"exim -bd -q10m"\ I get \*PANIC LOG: exec of exim -q failed*\.
532 A0024: This probably means that Exim doesn't know its own path so it can't
533 re-exec itself to do the first queue run. Check the output of
535 ==> exim -bP exim_path
538 Q0025: I can't seem to get a pipe command to run when I include a \"${if"\
539 expansion in it. This fails:
541 ==> command = perl -T /usr/local/rt/bin/rtmux.pl \
542 rt-mailgate helpdesk \
543 ${if eq {$local_part}{rt} {correspond}{action}}
545 A0025: You need some internal quoting in there. Exim expands each individual
546 argument separately. Because you have (necessarily) got spaces in your
547 \"${if"\ item, you have to quote that argument. Try
549 ==> command = perl -T /usr/local/rt/bin/rtmux.pl \
550 rt-mailgate helpdesk \
551 "${if eq {$local_part}{rt} {correspond}{action}}"
553 \**Warning:**\ If command starts with an item that requires quoting,
554 you cannot just put it in quotes, because a leading quote means that the
555 entire option setting is being quoted. What you have to do is to quote
556 the entire value, and use internally escaped quotes for the ones you
557 really want. For example:
559 ==> command = "\"${if ....}\" arg1 arg2"
561 Any backslashes in the expansion items will have to be doubled to stop
562 them being interpreted by the string reader.
565 Q0026: I'm trying to get Exim to connect an alias to a pipe, but it always
566 gives error code 69, with the comment \*(could mean service or program
569 A0026: If your alias entry looks like this:
571 ==> alias: |"/some/command some parameters"
573 change it to look like this:
575 ==> alias: "|/some/command some parameters"
578 Q0027: What does the error \*Spool file is locked*\ mean?
580 A0027: This is not an error. All it means is that when an Exim delivery
581 process (probably started by a queue runner process) looked at a message
582 in order to start delivering it, it found that another Exim process was
583 already busy delivering it. On a busy system this is quite a common
584 occurrence. If you set \"-skip_delivery"\ in the \log_selector\ option,
585 these messages are omitted from the log.
587 The only time when this message might indicate a problem is if it is
588 repeated for the same message for a very long time. That would suggest
589 that the process that is delivering the message has somehow got stuck.
592 Q0028: Exim is reporting IP addresses as 0.0.0.0 or 255.255.255.255 instead of
593 their correct values. What's going on?
595 A0028: You are using a version of Exim built with gcc on an IRIX box.
599 Q0029: I can't seem to figure out why PAM support doesn't work correctly.
601 A0029: There is a problem using PAM with shadow passwords when the calling
602 program is not running as \/root/\. Exim is normally running as the
603 Exim user when authenticating a remote host. See this posting for one
604 way round the problem:
606 \?http://www.exim.org/mailman/htdig/exim-users/Week-of-Mon-20010917/030371.html?\
608 Another solution can be found at \?http://www.e-admin.de/pam_exim/?\.
610 PAM 0.72 allows authorization as non-\/root/\, using setuid helper programs.
611 Furthermore, in \(/etc/pam.d/exim)\ you can explicitelly specify that
612 this authorization (using setuid helpers) is only permitted for certain
616 Q0030: I'm trying to use a query-style lookup for hosts that are allowed to
617 relay, but it is giving really weird errors.
619 A0030: Does your query contain a colon character? Remember that host lists are
620 colon-separated, so you need to double any colons in the query. This
621 applies even if the query is defined as a macro.
624 Q0031: Exim is rejecting connections from hosts that have more than one IP
625 address, for no apparent reason.
627 A0031: You are using Solaris 7 or earlier, and have \"nis dns files"\ in
628 \(/etc/nsswitch.conf)\. Change this to \"dns nis files"\ to avoid hitting Sun
629 bug 1154236 (a bad interaction between NIS and the DNS).
632 Q0032: Exim is failing to find the MySQL library, even though is it present
633 within \\LD_LIBRARY_PATH\\. I'm getting this error:
635 ==> /usr/local/bin/exim: fatal: libmysqlclient.so.6: open failed:
636 No such file or directory
638 A0032: Exim is suid, and \\LD_LIBRARY_PATH\\ is ignored for suid binaries on a
639 Solaris (and other?) systems. What you should be doing is adding
640 \"-R/local/lib/mysql"\ to the same place in the compilation that you added
641 \"-L/local/lib/mysql"\. This tells the binary where to look without
642 needing a path variable.
645 Q0033: What does the error \*lookup of host "xx.xx.xx" failed in yyy router*\
648 A0033: You configured a \%manualroute%\ router to send the message to xx.xx.xx. When
649 it tried to look up the IP address for that host, the lookup failed
650 with a permanent error. As this is a manual routing, this is a
651 considered to be a serious error which the postmaster needs to know
652 about (maybe you have a typo in your file), and there is little point
653 in keeping on trying. So it freezes the message.
655 (1) Don't set up routes to non-existent hosts.
657 (2) If you must set up routes to non-existent hosts, and don't want
658 freezing, set the \host_find_failed\ option on the router to do something
662 Q0034: Exim works fine on one host, but when I copied the binary to another
663 identical host, it stopped working (it could not resolve DNS names).
665 A0034: Is the new host running exactly the same operating system? Most
666 importantly, are the versions of the dynamically loaded libraries
667 (files with names like \(libsocket.so.1)\) the same on both systems? If not,
668 that is probably the cause of the problem. Either arrange for the
669 libraries to be the same, or rebuild Exim from source on the new host.
672 Q0035: I set a \"hosts"\ condition in an ACL to do a lookup in a file of IP
673 addresses, but it doesn't work.
675 A0035: Did you remember to put \"net-"\ at the start of the the search type? If
676 you set something like this:
678 ==> accept hosts = lsearch;/some/file
680 Exim searches the file for the host name, not the IP address. You need
683 ==> accept hosts = net-lsearch;/some/file
685 to make it use the IP address as the key to the lookup.
688 Q0036: Why do I get the error \*Permission denied: creating lock file hitching
689 post*\ when Exim tries to do a local delivery?
691 A0036: Your configuration specifies that local mailboxes are all held in
692 single directory, via configuration lines like these (taken from the
693 default configuration):
697 file = /var/mail/$local_part
699 and the permissions on the directory probably look like this:
701 ==> drwxrwxr-x 3 root mail 512 Jul 9 13:48 /var/mail/
703 Using the default configuration, Exim runs as the local user when doing
704 a local delivery, and it uses a lock file to prevent any other process
705 from updating the mailbox while it is writing to it. With those
706 permissions the delivery process, running as the user, is unable to
707 create a lock file in the \(/var/mail(\ directory. There are two solutions
710 (1) Set the \"write"\ and \"sticky bit"\ permissions on the directory, so
711 that it looks like this:
713 ==> drwxrwxrwt 3 root mail 512 Jul 9 13:48 /var/mail/
715 The \"w"\ allows any user to create new files in the directory, but
716 the \"t"\ bit means that only the creator of a file is able to remove
717 it. This is the same setting as is normally used with the \(/tmp)\
720 (2) Arrange to run the local_delivery transport under a specific group
721 by changing the configuration to read
725 file = /var/mail/${local_part}
728 The delivery process still runs under the user's uid, but with the
729 group set to \"mail"\. The group permission on the directory allows
730 the process to create and remove the lock file.
732 The choice between (1) and (2) is up to the administrator. If the
733 second solution is used, users can empty their mailboxes by updating
734 them, but cannot delete them.
736 If your problem involves mail to \/root/\, see also Q0507.
739 Q0037: I am experiencing mailbox locking problems with Sun's \"mailtool"\ used
742 A0037: See Q9705 in the Sun-specific section below.
745 Q0038: What does the error message \*error in forward file (filtering not
746 enabled): missing or malformed local part*\ mean?
748 A0038: If you are trying to use an Exim filter, you have forgotten to enable
749 the facility, which is disabled by default. In the \%redirect%\ router
750 (in the Exim run time configuration file) you need to set
752 ==> allow_filter = true
754 to allow a \(.forward)\ file to be used as an Exim filter. If you are not
755 trying to use an Exim filter, then you have put a malformed address in
756 the \(.forward)\ file.
759 Q0039: I have installed Exim, but now I can't mail to \/root/\ any more. Why is
762 A0039: Most people set up \/root/\ as an alias for the manager of the host. If
763 you haven't done this, Exim will attempt to deliver to \/root/\ as if it
764 were a normal user. This isn't really a good idea because the delivery
765 process would run as \/root/\. Exim has a trigger guard in the option
767 ==> never_users = root
769 in the default configuration file. This prevents it from running as \/root/\
770 when doing any deliveries. If you really want to run local deliveries as
771 \/root/\, remove this line, but it would be better to create an alias for
775 Q0040: How can I stop undeliverable bounce messages (e.g. to routeable, but
776 undeliverable, spammer senders) from clogging up the queue for days?
778 A0040: If at all possible, you should try to avoid getting into this situation
779 in the first place, for example, by verifying recipients so that you
780 do not accept undeliverable messages that lead to these bounces.
781 You can, however, configure Exim to discard failing bounce messages
782 early. Just set \ignore_bounce_errors_after\ to specify a (short) time
786 Q0041: What does the message \*unable to set gid=ddd or uid=ddd (euid=ddd):
787 local delivery to ... transport=ttt*\ mean?
789 A0041: Have you remembered to make Exim setuid \/root/\? It needs root privilege if
790 it is to do any local deliveries, because it does them ``as the user''.
791 Note also that the partition from which Exim is running (where the
792 binary is installed) must not have the \nosuid\ mount option set. You
793 can check this by looking at its \(/etc/fstab)\ entry (or \(/etc/vfstab)\,
794 depending on your OS).
797 Q0042: My ISP's mail server is rejecting bounce messages from Exim, complaining
798 that they have no sender. The SMTP trace does indeed show that the
799 sender address is \"<>"\. Why is the Sender on the bounce message empty?
801 A0042: Because the RFCs say it must be. Your ISP is at fault. Send them this
802 extract from RFC 2821 section 6.1 (\*Reliable Delivery and Replies by
805 If there is a delivery failure after acceptance of a message, the
806 receiver-SMTP MUST formulate and mail a notification message. This
807 notification MUST be sent using a null (\"<>"\) reverse path in the
808 envelope. The recipient of this notification MUST be the address
809 from the envelope return path (or the ::Return-Path:: header line).
810 However, if this address is null (\"<>"\), the receiver-SMTP MUST NOT
813 The reason that bounce messages have no sender is so that they
814 themselves cannot provoke further bounces, as this could lead to a
815 unending exchange of undeliverable messages.
818 Q0043: What does the error \*Unable to get interface configuration: 22 Invalid
821 A0043: This is an error that occurs when Exim is trying to find out the all the
822 IP addresses on all of the local host's interfaces. If you have lots of
823 virtual interfaces, this can occur if there are more than around 250 of
824 them. The solution is to set the option \local_interfaces\ to list just
825 those IP addresses that you want to use for making and receiving SMTP
829 Q0044: What does the error \*Failed to create spool file*\ mean?
831 A0044: Exim has been unable to create a file in its spool area in which to
832 store an incoming message. This is most likely to be either a
833 permissions problem in the file hierarchy, or a problem with the uid
834 under which Exim is running, though it could be something more drastic
835 such as your disk being full.
837 If you are running Exim with an alternate configuration file using a
838 command such as \"exim -C altconfig..."\, remember that the use of -C
839 takes away Exim's root privilege.
841 Check that you have defined the spool directory correctly by running
843 ==> exim -bP spool_directory
845 and examining the output. Check the mode of this directory. It should
846 look like this, assuming you are running Exim as user \/exim/\:
848 ==> drwxr-x--- 6 exim exim 512 Jul 16 12:29 /var/spool/exim
850 If there are any subdirectories already in existence, they should have
851 the same permissions, owner, and group. Check also that you haven't got
852 incorrect permissions on superior directories (for example, \(/var/spool)\).
853 Check that you have set up the Exim binary to be setuid \/root/\. It should
856 ==> -rwsr-xr-x 1 root xxx 502780 Jul 16 14:16 exim
858 Note that it is not just the owner that must be \/root/\, but also the third
859 permission must be \"s"\ rather than \"x"\.
862 Q0045: I see entries in the log that mention two different IP addresses for the
863 same connection. Why is this? For example:
865 ==> H=tip-mp8-ncs-13.stanford.edu ([36.173.0.189]) [36.173.0.156]
867 A0045: The actual IP address from which the call came is the final one.
868 Whenever there's something in parentheses in a host name, it is what the
869 host quoted as the domain part of an SMTP HELO or EHLO command. So in
870 this case, the client, despite being 36.173.0.156, issued the command
872 ==> EHLO [36.173.0.189]
874 when it sent your server the message. This is, of course, very
878 Q0046: A short time after I start Exim I see a defunct zombie process. What
881 A0046: Your system must be lightly loaded as far as mail is concerned. The
882 daemon sets off a queue runner process when it is started, but it only
883 tidies up completed child processes when it wakes up for some other
884 reason. When there's nothing much going on, you occasionally see
885 defunct processes like this waiting to be dealt with. This is
889 Q0047: On a reboot, or a restart of the mail system, I see the message \*Mailer
890 daemons: exim abandoned: unknown, malformed, or incomplete option
891 -bz sendmail*\. What does this mean?
893 A0047: \-bz-\ is a Sendmail option requesting it to create a `configuration freeze
894 file'. Exim has no such concept and so does not support the option. You
895 probably have a line like
897 ==> /usr/lib/sendmail -bz
899 in some start-up script (e.g. \(/etc/init.d/mail)\) immedately before
901 ==> /usr/lib/sendmail -bd -q15m
903 The first of these lines should be commented out.
906 Q0048: Whenever exim restarts it takes up to 3-5 minutes to start responding on
907 the SMTP port. Why is this?
909 A0048: Something else is hanging onto port 25 and not releasing it. One place
910 to look is \(/etc/inetd.conf)\ in case for any reason an SMTP stream is
914 Q0049: What does the log message \*no immediate delivery: more than 10 messages
915 received in one connection*\ mean?
917 A0049: A remote MTA sent a number of messages in a single SMTP session. Exim
918 limits the number of immediate delivery processes it creates as a
919 result of a single SMTP connection, in order to avoid creating a zillion
920 processes on systems that can have many incoming connections. If you are
921 dialing in to collect mail from your ISP, you should probably set
922 \smtp_accept_queue_per_connection\ to some number larger than 10, or
923 arrange to start a queue runner for local delivery (using \-ql-\)
924 immediately after collecting the mail.
927 Q0050: I am getting complaints from a customer who uses my Exim server for
928 relaying that they are being blocked with a \*Too many connections*\
931 A0050: See \smtp_accept_max\, \smep_accept_max_per_host\ and \smtp_accept_reserve\.
934 Q0051: When I try \"exim -bf"\ to test a system filter, I received the following
935 error message: \*Filter error: unavailable filtering command "fail" near
936 line 8 of filter file*\.
938 A0051: Use the \-bF-\ option to test system filters. This gives you access to the
939 freeze and fail actions.
942 Q0052: What does \*ridiculously long message header*\ in an error report mean?
944 A0052: There has to be some limit to the length of a message's header lines,
945 because otherwise a malefactor could open an SMTP channel to your host,
946 start a message, and then just send characters continuously until your
947 host ran out of memory. (Exim stores all the header lines in main
948 memory while processing a message). For this reason a limit is imposed
949 on the total amount of memory that can be used for header lines. The
950 default is 1MB, but this can be changed by setting \\HEADER_MAXSIZE\\ in
951 \(Local/Makefile)\ before building Exim. Exceeding the limit provokes
952 the ``ridiculous'' error message.
955 Q0053: Exim on my host responds to a connection with \"220 *****..."\ and
956 won't understand \\EHLO\\ commands.
958 A0053: This is the sign of a Cisco Pix ``Mailguard'' sitting in front of your
959 MTA. Pix breaks ESMTP and only does SMTP. It is a nuisance when you have
960 a secure MTA running on your box. Something like ``no fixup protocol
961 smtp 25'' in the Pix configuration is needed. It may be possible to do
962 this by logging into the Pix (using \^telnet^\ or \^ssh^\) and typing
963 \"no fixup smtp"\ to its console. (You may need to use other commands
964 before or after to set up configuration mode and to activate a changed
965 configuration. Consult your Pix documentation or expert.) See also
969 Q0054: I'm getting an Exim configuration error \*unknown rewrite flag
970 character (m) in line 386*\ but I haven't used any flags on my rewriting
973 A0054: You have probably forgotten to quote a replacement string that contains
977 Q0055: What does the error \*Failed to open wait-remote_smtp database: Invalid
980 A0055: This is something that happens if you have existing DBM hints files when
981 you install a new version of Exim that is compiled to use a different or
982 upgraded DBM library. The simplest thing to try is
984 ==> rm /var/spool/exim/db/*
986 This removes all the hints files. Exim will start afresh and build new
987 ones. If the symptom recurs, it suggests there is some problem with your
991 Q0056: We are using Exim to send mail from our web server. However, whenever a
992 user sends an email it gets sent with the return path (envelope sender)
993 //apache@server_name.com// because the PHP script is running as
996 A0056: You need to include \/apache/\ in the \trusted_users\ configuration option.
997 Only trusted users are permitted to specify senders when mail is passed
998 to Exim via the command line.
1001 Q0057: We've got people complaining about attachments that don't show up
1002 as attachments, but are included in the body of the message.
1004 A0057: These symptoms can be seen when some software passes a CRLF line
1005 terminated message via the command line to an MTA that expects lines to
1006 be terminated by LF only, and so preserves the CRs as data. If you can
1007 identify the software that is doing this, try setting the \-dropcr-\
1008 option on the command it uses to call Exim. Alternatively, you can set
1009 \drop_cr\ in the configuration file, but then that will apply to all
1013 Q0058: What does the error \*failed to open DB file \(/var/spool/exim/db/retry)\:
1016 A0058: This error is most often caused when a hints file that was written with
1017 one version of the Berkeley DB library is read by another version.
1018 Sometimes this can happen if you change from a binary version of Exim to
1019 a locally compiled version. Or it can happen if you compile and install
1020 a new version of Exim after changing Berkeley DB versions. You can find
1021 out which version your Exim is using by running:
1023 ==> ldd /usr/sbin/exim
1025 The solution to the problem is to delete all the files in the
1026 \(/var/spool/exim/db)\ directory, and let Exim recreate them.
1029 Q0059: When my Outlook Express 6.0 client sends a STARTTLS command to begin a
1030 TLS session, Exim doesn't seem to receive it. The Outlook log shows
1033 ==> SMTP: 14:19:27 [tx] STARTTLS
1034 SMTP: 14:19:27 [rx] 500 Unsupported command.
1036 but the Exim debugging output shows this:
1038 ==> SMTP<< EHLO xxxx
1039 SMTP>> 250-yyyy Hello xxxx [nnn.nnn.nnn.nnn]
1042 250-AUTH CRAM-MD5 PLAIN LOGIN
1047 A0059: Turn off scanning of outgoing email in Norton Antivirus. If you aren't
1048 running Norton Antivirus, see if you are running some other kind of SMTP
1049 proxying, either on the client or on a firewall between the client and
1050 server. ``Unsupported command'' is not an Exim message.
1053 Q0060: Why am I getting the error \*failed to expand \"/data/lists/lists/${lc"\
1054 for require_files: \"${lc"\ is not a known operator*\ for this setting:
1056 ==> require_files = MAILMAN_HOME/lists/${lc:$local_part}/config.db
1058 A0060: The value of \"require_files"\ is a \*list*\ in which each item is
1059 separately expanded. You need either to double the colon, or switch to
1060 a different list separator.
1063 Q0061: What does the error \*Too many ``Received'' headers - suspected mail
1066 A0061: Whenever a message passes through an MTA, a ::Received:: header gets
1067 added. Exim counts the number of these headers in incoming messages. If
1068 there are more than the value of \received_headers_max\ (default 30),
1069 Exim assumes there is some kind of mail routing loop occurring. For
1070 example, host A passes the message to host B, which immediately passes
1071 it back to host A. Check the ::Received:: headers and the mail logs to
1072 determine exactly what is going on.
1074 One common cause of this problem is users with accounts on both systems
1075 who set up each one to forward to the other, thinking that will cause
1076 copies of all messages to be delivered on both of them.
1079 Q0062: When I try to start an Exim daemon it crashes. I ran a debugger and
1080 discovered that the crash is happening in the function \^^getservbyname()^^\.
1083 A0062: What have you got in the file \(/etc/nsswitch.conf)\? If it contains this
1086 ==> services: db files
1088 try removing the \"db"\. (Your system is trying to look in some kind of
1089 database before searching the file \(/etc/services)\.)
1092 Q0063: When I try to start an Exim daemon, nothing happens. There is no
1093 process, and nothing is written to the Exim log.
1095 A0063: Check to see if anything is written to \(syslog)\. This problem can be
1096 caused by a permission problem that stops Exim from writing to its log
1097 files, especially if you've specified that they should be written
1098 somewhere other than under Exim's spool directory. You could also try
1099 running the daemon with debugging turned on.
1102 Q0064: When I run \"exim -d test@domain"\ it delivers fine, but when I send a
1103 message from the \^mail^\ command, I get \*User unknown*\ and the mail
1104 is saved in \(dead.letter)\.
1106 A0064: It looks as if Exim isn't being called by \^mail^\; instead it is
1107 calling some other program (probably Sendmail). Try running the command
1109 ==> /usr/sbin/sendmail -bV
1111 (If you get \*No such file or directory*\ or \*Command not found*\ you
1112 are running Solaris or IRIX. Try again with \(/usr/lib/sendmail)\.) The
1113 output should be something like this:
1115 ==> Exim version 4.05 #1 built 13-Jun-2002 10:27:15
1116 Copyright (c) University of Cambridge 2002
1118 If you don't see this, your Exim installation isn't fully operational.
1119 If you are running FreeBSD, see Q9201. For other systems, see Q0114.
1122 Q0065: When (as \/root/\) I use -C to run Exim with an alternate configuration
1123 file, it gives an error about being unable to create a spool file when
1124 trying to run an \%autoreply%\ transport. Why is this?
1126 A0065: When Exim is called with -C, it passes on -C to any instances of itself
1127 that it calls (so that the whole sequence uses the same config file). If
1128 it's running as \/exim/\ when it does this, all is well. However, if it
1129 happens as a consequence of a non-privileged user running \%autoreply%\,
1130 the called Exim gives up its root privilege. Then it can't write to the
1133 This means that you can't use -C (even as \/root/\) to run an instance of
1134 Exim that is going to try to run \%autoreply%\ from a process that is
1135 neither \/root/\ nor \/exim/\. Because of the architecture of Exim (using
1136 re-execs to regain privilege), there isn't any way round this
1137 restriction. Therefore, the only way you can make this scenario work is
1138 to run the \%autoreply%\ transport as \/exim/\ (that is, the user that
1139 owns the Exim spool files). This may be satisfactory for autoreplies
1140 that are essentially system-generated, but of course is no good for
1141 autoreplies from unprivileged users, where you want the \%autoreply%\
1142 transport to be run as the user. To get that to work with an alternate
1143 configuration, you'll have to use two Exim binaries, with different
1144 configuration file names in each. See S001 for a script that patches
1145 the configuration name in an Exim binary.
1148 Q0066: What does the message \*unable to set gid=xxx or uid=xxx*\ mean?
1150 A0066: This message is given when an Exim process is unable to change uid or
1151 gid when it needs to, because it does not have root privilege. This is a
1152 serious problem that prevents Exim from carrying on with what it is
1153 doing. The two most common situations where Exim needs to change uid/gid
1154 are doing local deliveries and processing users' filter files. There are
1155 two common causes of this error:
1157 (1) You have forgotten to make the exim binary setuid to \/root/\. This
1158 means that it can never change uid/gid in any situation. Also, the
1159 setuid binary must reside on a disk partition that does not have the
1160 \"nosuid"\ mount option set.
1162 (2) The exim binary is setuid, but you have configured Exim so that,
1163 while trying to verify an address at SMTP time, it runs a router
1164 that needs to change uid/gid. Because Exim runs as \/exim/\ and not
1165 \/root/\ while receiving messages, the router is unable to change
1166 uid and therefore it cannot operate. The usual example of this is a
1167 \%redirect%\ router for users' filter files.
1169 Setting the \user\ or \check_local_user\ options on a \redirect\
1170 router causes this to happen (except in the special case when the
1171 redirection list is provided by the \data\ option and does not
1172 contain \":include:"\).
1174 The solution is to set \no_verify\ on the router that is causing the
1175 problem. This means that it is skipped when an address is being
1176 verified. In ``normal'' configurations where the router is indeed
1177 handling users' filter files, this is quite acceptable, because you
1178 do not usually need to process a filter file in order to verify that
1179 the local part is valid. See, for example, the \%userforward%\
1180 router in the default configuration.
1183 Q0067: What does the error \*too many unrecognized commands*\ mean?
1185 A0067: There have been instances of network abuse involving mail sent out by
1186 web servers. In most cases, unrecognizable commands are sent as part of
1187 the SMTP session. A real MTA never sends out such invalid commands. Exim
1188 allows a few unrecognized commands in a session to permit humans who are
1189 testing to make a few typos (it responds with a 5xx error). However, if
1190 Exim receives too many such commands, it assumes that it is dealing with
1191 an abuse of some kind, and so it drops the connection.
1194 Q0068: Exim times out when trying to connect to some hosts, though those hosts
1195 are known to be up and running. What's the problem?
1197 A0068: There could be a number of reasons for this (see also Q0017). The
1198 obvious one is that there is a networking problem between the hosts.
1199 If you can ping between the hosts or connect in other ways, the problem
1200 might be caused by ECN (Explicit Congestion Notification) being enabled
1201 in your kernel. ECN uses TCP flags originally assigned to TOS - it's a
1202 "new" invention, and some hosts and routers are known to be confused if
1203 a client uses it. If you are running Linux, you can turn ECN off by
1204 running this command:
1206 ==> /bin/echo "0" > /proc/sys/net/ipv4/tcp_ecn
1208 This has also been reported to cure web connection problems from Mozilla
1209 and Netscape browsers in Linux when there were no problems with Windows
1213 Q0069: What does the error \*SMTP data timeout (message abandoned) on connection
1216 A0069: It means that there was a timeout while Exim was reading the contents of
1217 a message on an incoming SMTP connection. That is, it had successfully
1218 accepted a MAIL command, one or more RCPT commands, and a DATA command,
1219 and was in the process of reading the data itself. The length of timeout
1220 is controlled by the \smtp_receive_timeout\ option.
1222 If you get this error regularly, the cause may be incorrect handling of
1223 large packets by a router or firewall. The maximum size of a packet is
1224 restricted on some links; routers should split packets that are larger.
1225 There is a feature called ``path MTU discovery'' that enables a sender
1226 to discover the maximum packet size over an entire path (multiple
1227 Internet links). This can be broken by misconfigured firewalls and
1228 routers. There is a good explanation at \?http://www.netheaven.com/pmtu.html?\.
1229 Reducing the MTU on your local network can sometimes work round this
1230 problem. See Q0017 (3) for further discussion.
1233 Q0070: What does the error \*SMTP command timeout on connection from...*\ mean?
1235 A0070: Exim was expecting to read an SMTP command from the client, but no
1236 command was read within the \smtp_receive_timeout\ time limit.
1239 Q0071: What does the error \*failed to open DB file \(/var/spool/exim//db/retry)\:
1240 Illegal argument*\ mean?
1242 A0071: See Q0058. The cause of this error is usually the same.
1245 Q0072: Exim will deliver to normal aliases, and aliases that are pipes or
1246 files, but it objects to aliases that involve \":include:"\ items,
1247 complaining that it can't change gid or uid. Why is this?
1249 A0072: See Q0066 for a general answer. The problem happens during verification
1250 of an incoming SMTP message, not during delivery itself. In this
1251 particular case, you must have set up your aliasing router with a \user\
1252 setting. This causes Exim to change uid/gid when reading \":include:"\
1253 files. If you do not need the detailed verification provided by the
1254 router, the easy solution is to set \no_verify\ so that the router isn't
1255 used during verification.
1257 Otherwise, if you set \user\ on the router in order to provide a user
1258 for delivery to pipes or files, one solution is to put the \user\
1259 setting on the transports instead of on the router. You may need to
1260 create some special transports just for this router. The alternative is
1261 to supply two different routers, one with \user\ and \no_verify\, and
1262 the with \verify_only\ but no \user\ setting.
1265 Q0073: I'm seeing log file corruption, with parts of log lines getting mangled
1266 by other log entries.
1268 A0073: The only time this has been seen is when several servers were writing to
1269 the same log files over NFS. Exim assumes that its log file is on local
1270 disk, and using NFS, especially for more than one server, will not work.
1273 Q0074: What does the error message \*remote delivery process count got out of
1276 A0074: Exim uses subprocesses for remote deliveries; this error means that the
1277 master process expected to have a child process running, but found there
1278 were none. Prior to release 4.11, this error could be caused by running
1279 Exim under \^strace^\ on a Linux system, because stracing causes
1280 children to be ``stolen'' such that a parent that tries to wait for
1281 ``any of my children'' is told that it has none. Current releases of
1282 Exim have code to get round this problem.
1285 Q0075: I'm using LDAP, and some email addresses that contain special characters
1286 are causing parsing errors in my LDAP lookups.
1288 A0075: You should be using \"${quote_ldap:$local_part}"\ instead of just
1289 \"$local_part"\ in your lookups.
1292 Q0076: I've configured Exim to use \^syslog^\ for its logs, with the main and
1293 reject logs sent to different files, but whenever a message is rejected,
1294 I get one message on the reject log and two messages on the main log.
1296 A0076: You are probably putting your reject items into the main log as well;
1297 remember \^syslog^\ levels are inclusive (for example, \"mail.info"\
1298 includes all higher levels, so a \"mail.notice"\ message will be caught
1299 by a \"mail.info"\ descriptor).
1300 Test this by running the command:
1302 ==> logger -p mail.notice test
1304 and seeing which logs it goes into.
1307 Q0077: I've installed Exim and it is delivering mail just fine. However, when I
1308 try to read mail from my PC I get \*connection rejected*\ or \*unable to
1314 Q0078: Exim is logging the unknown SMTP command \"XXXX"\ from my client hosts,
1315 and they are unable to authenticate.
1317 A0078: This is a sign of a Cisco PIX firewall getting in the way. It does not
1318 support ESMTP, and turns EHLO commands into XXXX. You should configure
1319 the Pix to leave SMTP alone; see Q0053 for how to do this.
1322 Q0079: Our new PIX firewall is causing problems with incoming mail. How can
1325 A0079: See Q0053 and Q0078. If some messages get through and others do not,
1329 Q0080: Am I to understand that the database lookups must only return one value?
1330 They can not return a list of values? The documentation seems to
1331 indicate that it's possible to return a list.
1333 A0080: Lookups can be used in two different situations, and what they return is
1334 different in the two cases. (Be thankful Exim 3 is gone; there was yet
1337 (1) You can use a lookup in any expanded string. The syntax is
1339 ==> ${lookup ..... }
1341 In this case, whatever is looked up replaces the expansion item. It
1342 may be one value or a list of values. Whether a single value or a
1343 list is acceptable or not depends on where you are using the string
1344 expansion. If it is for an option that expects just one value, then
1345 only one value is allowed (for example).
1347 (2) You can make use of the lookup mechanism to test whether something
1348 (typically a host name or IP address) is in a list. For example,
1350 ==> hosts = a : b : c
1352 in an ACL tests whether the calling host's name matches ``a'', or
1353 ``b'', or ``c''. Now, suppose you want to keep the list of names in
1354 a database, or cdb file, or NIS map, or... By writing
1356 ==> hosts = pgsql;select ....
1358 you are saying to Exim: ``Run this lookup; if it succeeds, behave as
1359 if the host is in the list; if it fails, the host is not in the
1360 list.'' You are using the indexing mechanism of the database as a
1361 fast way of checking a list. A simpler example is
1363 ==> hosts = lsearch;/some/file
1365 where the file contains the list of hosts to be searched.
1367 The complication happens when a list is first expanded before being
1368 interpreted as a list. This happens in a lot of cases. You can therefore
1369 write either of these:
1371 ==> hosts = cdb;/some/file
1372 hosts = ${lookup{something}cdb{/some/file}}
1374 but they have different meanings. The first means ``see if the host name
1375 is in the list in this file''. The second means ``run this lookup and
1376 use the result of the lookup as a list of host items to check''. In the
1377 second case, the list could contain multiple values (colon separated),
1378 and one of those values could even be ``cdb;/some/file''.
1380 Flexibility does lead to complexity, I'm afraid.
1383 Q0081: What does \*error in redirect data: included file xxxx is too big*\
1386 A0081: You are trying to include a very large file in a redirection list, using
1387 the \":include:"\ feature. Exim has a built-in limit on the size, as a
1388 safety precaution. The default is 1 megabyte. If you want to increase
1389 this, you have to rebuild Exim. In your \(Local/Makefile)\, put
1391 ==> MAX_INCLUDE_SIZE = whatever
1393 and then rebuild Exim. The value is a number of bytes, but you can give
1394 it as a parenthesized arithmetic expression such as \"(3*1024*1024)"\.
1395 However, an included file of more than a megabyte is likely to be quite
1396 inefficient. How many addresses does yours contain? You get the best
1397 performance out of Exim if you arrange to send mailing list messages
1398 with no more than about 100 recipients (in order to get parallelism in
1402 Q0082: What does \*relocation error: /lib/libnss_dns.so.2: symbol
1403 __libc_res_nquery, version GLIBC_PRIVATE not defined in file
1404 libresolv.so.2 with link time reference*\ mean?
1406 A0082: You have updated \^glibc^\ while an Exim daemon is running. Stop and
1410 Q0083: Netscape on Unix is sending messages containing an unqualified user name
1411 in the ::Sender:: header line, which Exim is rejecting because I have
1412 set \"verify = header_syntax"\. How can I fix this?
1414 A0083: The only thing you can do in Exim is to set the
1415 \sender_unqualified_hosts\ option to allow unqualified sender addresses
1416 form the relevant hosts; of course, this applies to all sender
1417 addresses, not just the ::Sender:: header line.
1419 Alternatively, you can configure Netscape not to include the header line
1420 in the first place. Add the following line to the
1421 \($HOME/.netscape/preferences.js)\ and \($HOME/.netscape/liprefs.js)\
1424 ==> user_pref("mail.suppress_sender_header", true);
1426 Netscape \*must*\ be shutdown while doing this.
1429 Q0084: I want to set up an alias that pipes a message to \^gpg^\ and then pipes
1430 the result to \^mailx^\ to resubmit the message, but when I use my
1431 tested command in an alias file, I get an error from \^gpg^\.
1433 A0084: Probably you are using a shell command with two pipe symbols in it. An
1436 ==> gpg-xxx: "|gpg <options> | mailx <options"
1438 does not work, because Exim does not run pipes under a shell by default.
1439 You must call a shell explicitly if you want to make use of the shell's
1440 features for double-piping, either by piping to \"/bin/sh"\ with a
1441 suitable \"-c"\ option, or by piping to a shell script.
1444 Q0085: I see a lot of \*rejected EHLO ... syntactically invalid argument(s)*\.
1445 I know it's because of the underscore in the host name, but is there a
1446 switch to allow Exim to accept mail from such hosts?
1448 A0085: Yes. Add this to your configuration:
1450 ==> helo_allow_chars = _
1452 For more seriously malformed host names, see \helo_accept_junk_hosts\.
1456 Q0086: What does \*SMTP protocol violation: synchronization error (next input
1457 sent too soon)*\ mean?
1459 A0086: SMTP is a ``lock-step'' protocol, which means that, at certain points in
1460 the protocol, the client must wait for the server to respond before
1461 sending more data. Exim checks for correct behaviour, and issues this
1462 error if the client sends data too soon. This protects against
1463 malefactious clients who send a bunch of SMTP commands (usually to
1464 transmit spam) without waiting for any replies.
1466 This error is also provoked if the client is trying to start up a TLS
1467 session immediately on connection, without using the STARTTLS command.
1468 See Q1707 for a discussion of this case.
1471 Q0087: What does \*rejected after DATA: malformed address: xx@yy may not follow
1472 <xx@yy> : failing address in "from" header*\ mean? (I've obscured the
1473 real email addresses.)
1475 A0087: Your DATA ACL contains
1477 ==> verify = header_syntax
1479 and an incoming message contained the line
1481 ==> From: xx@yy <xx@yy>
1483 This is syntactically invalid. The contents of an address in a header
1484 line are either just the address, or a ``phrase'' followed by an address
1485 in angle brackets. In the latter case, the ``phrase'' must be quoted if
1486 it contains special characters such as @. The following are valid
1487 versions of the bad header:
1490 From: "xx@yy" <xx@yy>
1492 though why on earth anything generates this kind of redundant nonsense I
1496 Q0088: The Windows mailer SENDFILE.EXE sometimes hangs while trying to send a
1497 message to Exim 4, and eventually times out. It worked flawlessly with
1498 Exim 3. What has changed?
1500 A0088: Exim 4 sets an obscure TCP/IP parameter called TCP_NODELAY. This
1501 disables the "Nagle algorithm" for the TCP/IP transmission. The Nagle
1502 algorithm can improve network performance in interactive situations such
1503 as a human typing at a keyboard, by buffering up outgoing data until the
1504 previous packet has been acknowledged, and thereby reducing the number
1505 of packets used. This is not relevant for mail transmission, which
1506 mostly consists of quite large blocks of data; setting TCP_NODELAY
1507 should improve performance. However, it seems that some Windows clients
1508 do not function correctly if the server turns off the Nagle algorithm.
1509 If you are using Exim 4.23 or later, you can set
1511 ==> tcp_nodelay = false
1513 This stops Exim setting TCP_NODELAY on the sockets created by the
1517 Q0089: What does the error \*kernel: application bug: exim(12099) has SIGCHLD
1518 set to SIG_IGN but calls wait()*\ mean?
1520 A0089: This was a bad interaction between a relatively recent change to the
1521 Linux kernel and some ``belt and braces'' programming in Exim. The
1522 following explanation is taken from Exim's change log:
1524 When Exim is receiving multiple messages on a single connection, and
1525 spinning off delivery processess, it sets the SIGCHLD signal handling to
1526 SIG_IGN, because it doesn't want to wait for these processes. However,
1527 because on some OS this didn't work, it also has a paranoid call to
1528 \^waitpid()^\ in the loop to reap any children that have finished. Some
1529 versions of Linux now complain (to the system log) about this
1530 ``illogical'' call to \^waitpid()^\. I have therefore put it inside a
1531 conditional compilation, and arranged for it to be omitted for Linux.
1533 I am pretty sure I caught all the places in Exim where this happened.
1534 However, there are still occasional reports of this error. I have not
1535 heard of any resolutions, but my current belief is that they are caused
1536 by something that Exim calls falling foul of the same check. There was
1537 at one time a suspicion that the IPv6 stack was involved.
1540 Q0090: I can't seem to get a pipe command to run when I include a \"${lookup"\
1546 Q0091: Why is Exim giving the error \*Failed to send message from address_reply
1547 transport*\ when I run it using -C to specify an alternate
1554 1. BUILDING AND INSTALLING
1556 Q0101: I'm having a problem with an Exim RPM.
1558 A0101: Normally the thing to do if you have a problem with an RPM package is
1559 to contact the person who built the package first, not the person who
1560 made the software that's in the package. You can usually find out who
1561 made a package using the following command:
1563 ==> rpm --query --package --queryformat '%{PACKAGER}\n' <rpm-package-file>
1565 where \[rpm-package-file]\ is the actual file, e.g. \(exim-3.03-2.i386.rpm)\.
1566 Or, if the package is installed on your system:
1568 ==> rpm --query --queryformat '%{PACKAGER}\n' <package-name>
1570 where \[package-name]\ is the name component of the package, e.g. \"exim"\.
1571 If the packager is unable or unwilling to help, only then should you
1572 contact the actual author or associated mailing list of the software.
1574 If you discover through the querying process that you can't tell who
1575 the person (or company or group) is who built the package, or that they
1576 no longer exist at the given address, then you should reconsider
1577 whether you want a package from an unknown source on your system.
1579 If you discover through the querying process that you yourself are the
1580 person who built the package, then you should either (a) contact the
1581 author or associated mailing list, or (b) reconsider whether you ought
1582 to be building and distributing RPM packages of software you don't
1585 Similar rules of thumb govern other binary package formats, including
1586 debs, tarballs, and POSIX packages.
1589 Q0102: I can't get Exim to compile with Berkeley DB version 2.x or 3.x.
1591 A0102: Have you set \"USE_DB=yes\" in \(Local/Makefile)\? This causes Exim to use the
1592 native interface to the DBM library instead of the compatibility
1593 interface, which needs a header called \(ndbm.h)\ that may not exist on your
1597 Q0103: I'm getting an \*undefined symbol*\ error for \"hosts_ctl"\ when I try to
1598 build Exim. (On some systems this error is \*undefined reference to
1601 A0103: You should either remove the definition of \\USE_TCP_WRAPPERS\\ or add
1602 \"-lwrap"\ to your \\EXTRALIBS\\ setting in Local/Makefile.
1605 Q0104: I'm about to upgrade to a new Exim release. Do I need to ensure the
1606 spool is empty, or take any other special action?
1608 A0104: It depends on where you are coming from.
1610 (1) If you are changing to release 4.00 or later from a release prior to
1611 4.00, you will need to make changes to the run time configuration file.
1612 See the file \(doc/Exim4.upgrade)\ for details. If you are coming from
1613 before release 3.00, you should also see \(doc/Exim3.upgrade)\.
1615 (2) If you are upgrading from an Exim 4 release to a later release, you
1616 do not need to take special action. New releases are made backwards
1617 compatible with old spool files and hints databases, so that upgrading
1618 can be done on a running system. All that should be necessary is to
1619 install a new binary and then HUP the daemon.
1622 Q0105: What does the error \*install-info: command not found*\ mean?
1624 A0105: You have set \\INFO_DIRECTORY\\ in your \(Local/Makefile)\, and Exim is trying
1625 to install the Texinfo documentation, but cannot find the command called
1626 \(install-info)\. If you have a version of Texinfo prior to 3.9, you
1627 should upgrade. Otherwise, check your installation of Texinfo to see why
1628 the \(install-info)\ command is not available.
1631 Q0106: Exim doesn't seem to be recognizing my operating system type correctly,
1632 and so is failing to build.
1634 A0106: Run the command \"scripts/os-type -generic"\. The output should be one of
1635 the known OS types, and should correspond to your operating system. You
1636 can see which OS are supported by obeying \"ls OS/Makefile-*"\ and looking
1637 at the file name suffixes.
1639 If there is a discrepancy, it means that the script is failing to
1640 interpret the output from the \"uname"\ command correctly, or that the
1641 output is wrong. Meanwhile, you can build Exim by obeying
1643 ==> EXIM_OSTYPE=xxxx make
1645 instead of just \"make"\, provided you are running a Bourne-compatible
1646 shell, or otherwise by setting \\EXIM_OSTYPE\\ correctly in your
1647 environment. It is probably best to start again from a clean
1648 distribution, to avoid any wreckage left over from the failed attempt.
1651 Q0107: Exim fails to build, complaining about the absence of the \"killpg"\
1654 A0107: This function should be present in all modern flavours of Unix. If you
1655 are using an older version, you should be able to get round the problem
1658 ==> #define killpg(pgid,sig) kill(-(pgid),sig)
1660 into the file called \(OS/os.h-xxx)\, where xxx identifies your operating
1661 system, and is the output of the command \"scripts/os-type -generic"\.
1664 Q0108: I'm getting an unresolved symbol \"ldap_is_ldap_url"\ when trying to build
1667 A0108: You must have specified \"LOOKUP_LDAP=yes"\ in the configuration. Have you
1668 remembered to set \"-lldap"\ somewhere (e.g. in \\LOOKUP_LIBS\\)? You need that
1669 in order to get the LDAP library scanned when linking.
1672 Q0109: I'm getting an unresolved symbol \"mysql_close"\ when trying to build Exim.
1674 A0109: You must have specified \"LOOKUP_MYSQL=yes"\ in the configuration. Have you
1675 remembered to set \"-lmysqlclient"\ somewhere (e.g. in \\LOOKUP_LIBS\\)? You
1676 need that in order to get the MySQL library scanned when linking.
1679 Q0110: I'm trying to build Exim with PAM support. I have included \"-lpam"\ in
1680 \\EXTRALIBS\\, but I'm still getting a linking error:
1682 ==> /lib/libpam.so: undefined reference to `dlerror'
1683 /lib/libpam.so: undefined reference to `dlclose'
1684 /lib/libpam.so: undefined reference to `dlopen'
1685 /lib/libpam.so: undefined reference to `dlsym'
1687 A0110: Add \"-ldl"\ to \\EXTRALIBS\\. In some systems these dynamic loading functions
1688 are in their own library.
1691 Q0111: I'm getting the error \*db.h: No such file or directory*\ when I try to
1694 A0111: This problem has been seen with RedHat 7.0, but could also happen in
1695 other environments. If your system is using the DB library, you
1696 need to install the DB development package in order to build Exim.
1697 The package is called something like \"db3-devel-3.1.14-16.i386.rpm"\ for
1698 Linux systems, but you should check which version of DB you have
1699 installed (current releases are DB 4).
1702 Q0112: I'm getting the error \*/usr/bin/ld: cannot find -ldb*\ when I try to
1705 A0112: This is probably the same problem as Q0111.
1708 Q0113: I've compiled Exim and I've managed to start it but there was one
1709 problem - it always complained that \(libmsqlclient.so.10)\ was not found,
1710 even though this file is in \(/usr/local/lib/mysql/)\.
1712 A0113: Solaris: ensure you have this in your \(Local/Makefile)\:
1714 ==> LOOKUP_LIBS=-L/usr/local/lib/mysql -R/usr/local/lib/mysql
1716 Net/Open/FreeBSD: Run this command (or ensure it gets run automatically
1719 ==> ldconfig -m /usr/local/lib/mysql
1721 Linux: add \(/usr/local/lib/mysql)\ to \(/etc/ld.so.conf)\ and re-run \(ldconfig)\.
1724 ==> -Wl,-rpath -Wl,/usr/local/lib/mysql
1726 to EXTRA_LIBS and then re-link (this is similar to the Solaris solution
1727 above). This will probably also work on other systems that use GNU
1731 Q0114: How can I remove Sendmail from my system? I've built Exim and run \"make
1732 install"\, but it still doesn't seem to be fully operational.
1734 A0114: If you are running FreeBSD, see Q9201. Otherwise, you need to arrange
1735 that whichever of the paths \(/usr/sbin/sendmail)\ or \(/usr/lib/sendmail)\
1736 exists on your system is changed to refer to Exim. For example, you
1737 could use these commands (as \/root/\):
1739 ==> mv /usr/sbin/sendmail /usr/sbin/sendmail.original
1740 chmod u-s /usr/sbin/sendmail.original
1741 ln -s /path/to/exim /usr/sbin/sendmail
1743 The second command removes the setuid privilege from the old MTA, as a
1744 general safety precaution. In the third command, substitute the actual
1745 path to the Exim binary for \(/path/to/exim)\.
1748 Q0115: What does \*Can't open \(../scripts/newer)\: No such file or directory*\
1749 mean? I got it while trying to build Exim.
1751 A0115: You are using FreeBSD, or another OS that has a \^make^\ command which
1752 tries to optimize the running of commands. Exim's \(Makefile)\ contains
1753 targets with sequential commands like this:
1756 @cd pcre; $(MAKE) SHELL=$(SHELL) AR="$(AR)" $(MFLAGS) CC="$(CC)" \
1757 CFLAGS="$(CFLAGS) $(PCRE_CFLAGS)" \
1758 RANLIB="$(RANLIB)" HDRS="$(PHDRS)" \
1759 INCLUDE="$(INCLUDE) $(IPV6_INCLUDE) $(TLS_INCLUDE)"
1760 @if $(SHELL) $(SCRIPTS)/newer pcre/libpcre.a exim; then \
1761 /bin/rm -f exim eximon.bin; fi
1763 The second command assumes that the \"cd pcre"\ in the first command is
1764 no longer in effect. If you have \"-j3"\ in your default set of
1765 \"MAKEFLAGS"\, FreeBSD \^make^\ tries to optimize, and ends up up with both
1766 commands in the same shell process. The result is that \"$(SCRIPTS)"\
1767 (which has a value of \"../scripts"\) is not found.
1769 The simplest solution is to force \^make^\ to use backwards compatibility
1770 mode with each command in its own shell, by using the \-B\ flag. To
1771 ensure that this happens throughout the build, it's best to export it in
1779 Q0116: I have tried to build Exim with Berkeley DB 3 and 4, but I always get
1782 A0116: One common problem, especially when you have several different versions
1783 of BDB installed on the same host, is that the header files and library
1784 files for BDB are not in a standard place. You therefore need to tell
1785 Exim where they are, by setting INCLUDE and DBMLIB in your
1786 \(Local/Makefile)\. For example, I use this on my workstation when
1787 I want to build with DB 4.1:
1789 ==> INCLUDE=-I/opt/local/include/db-4.1
1790 DBMLIB=/opt/local/lib/db-4.1/libdb.a
1792 Specifying the complete library file like this will cause it to be
1793 statically linked with Exim. You'll have to check to see where these
1794 files are on your system. For example, on FreeBSD 5, the header is in
1795 \(/usr/local/include/db4)\ and the library is in \(/usr/local/lib)\ and
1796 called \(libdb4)\. In that environment, you could use:
1798 ==> INCLUDE=-I/usr/local/include/db4
1799 DBMLIB=-L/usr/local/lib -ldb4
1801 This time, DBMLIB is specifying the library directory (\(/usr/local/lib)\)
1802 and the name of the library (\(db4)\) separately. The name of the actual
1803 library file is \(/usr/local/lib/libdb4.something)\. If the library was
1804 compiled for dynamic linking, that will be used.
1807 Q0117: Is there a quick walk-through of an Exim install from source anywhere?
1809 A0117: Here! This is a contribution from a RedHat user, somewhat edited. On
1810 other operating systems things may be slightly different, but the
1811 general approach is the same.
1813 (1) Install the db needed for Exim. This needs to be done first if you
1814 don't have a DBM library installed. Go to \?http://www.sleepycat.com?\
1815 and download \(db-4.1.25.tar.gz)\, or whatever the current release is.
1818 ==> gunzip db-4.1.25.tar.gz
1819 tar -xvf db-4.1.25.tar
1826 (2) Add a user for use by Exim, unless you want to use an existing user
1831 (3) Now you can prepare to build Exim. Go to \?http://www.exim.org?\ or
1832 one of its mirrors, or the master ftp site
1833 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4?\, and download
1834 \(exim-4.20.tar.gz)\ or whatever the current release is. Then:
1836 ==> gunzip exim-4.20.tar.gz
1837 tar -xvf exim-4.20.tar
1839 cp src/EDITME Local/Makefile
1840 cp exim_monitor/EDITME Local/eximon.conf
1842 (4) Edit \(Local/Makefile)\:
1844 Comment out EXIM_MONITOR= unless you want to install the Exim
1845 monitor (it requires X-windows).
1847 Set the user you want Exim to use for itself:
1851 If your DBM library is Berkeley DB, set up to use its native interface:
1855 Make sure Exim's build can find the DBM library and its headers. If
1856 you've installed Berkeley DB 4 you'll need to have settings like this
1857 in \(Local/Makefile)\:
1859 ==> INCLUDE=-I/usr/local/BerkeleyDB.4.1/include
1860 DBMLIB=/usr/local/BerkeleyDB.4.1/lib/libdb.a
1862 (Check that the first directory contains the db.h file and that the
1863 second library exists.)
1865 You don't need to change anything else, but you might want to review
1866 the default settings in the ``must specify'' section.
1868 (4) Build Exim by running the \/make/\ command.
1870 (5) Install Exim by running, as \/root/\:
1874 You \*must*\ be \/root/\ to do this. You do not have to be root for any of
1875 the previous building activity.
1877 (6) Run some tests on Exim; see if it will do local and remote
1878 deliveries. Change the configuration if necessary (for example,
1879 uncommenting \group\ on the \%local_delivery%\ transport if you don't
1880 use a ``sticky bit'' directory).
1882 (7) Change Sendmail to Exim (of course you need to have had Sendmail
1883 installed to do this).
1885 ==> /etc/init.d/sendmail stop
1886 mv /usr/sbin/sendmail /usr/sbin/sendmail.org
1887 ln -s /usr/exim/bin/exim /usr/sbin/sendmail
1888 /etc/init.d/sendmail start
1890 (8) Check the Exim log. Either use the Exim monitor, or:
1892 ==> tail -f /var/spool/exim/log/mainlog
1895 Q0118: I've set \"LOOKUP_INCLUDE=-I/client/include"\ in Local/Makefile, but the
1896 compilation of \^exim_dumpdb^\ is ignoring this option and failing. Why?
1898 A0118: LOOKUP_INCLUDE is the special include file for lookup modules in Exim
1899 (e.g. mysql, LDAP). Confusingly, it doesn't apply to basic DBM code
1900 which is used also for other things. Try setting INCLUDE and DBMLIB
1901 instead. For example:
1904 INCLUDE=-I/client/include
1905 DBMLIB=/client/lib/libdb.a
1908 Q0119: I know there are some 3rd-party patches for Exim, for exiscan and
1909 other things. Where are they?
1911 A0119: Exiscan is at \?http://duncanthrax.net/exiscan-acl/?\.
1913 Scanexi is at \?http://w1.231.telia.com/~u23107873/scanexi.html?\
1915 A sample \^^local_scan()^^\ function for interfacing to \^uvscan^\ is
1916 at \?http://www.dcs.qmul.ac.uk/~mb/local_scan/?\.
1918 An interface to SpamAssassin at SMTP time is at
1919 \?http://marc.merlins.org/linux/exim/sa.html?\.
1921 A mini-HOWTO (PDF file) about scanning and virus scanning, and some RPMs
1922 can be found at \?http://www.timj.co.uk/linux/exim.php?\.
1926 2. ROUTING IN GENERAL
1928 Q0201: How can I arrange that messages larger than some limit are handled by
1931 A0201: You can use a \condition\ option on the router line this:
1933 ==> condition = ${if >{$message_size}{100K}{yes}{no}}
1936 Q0202: Can I specify a list of domains to explicitly reject?
1938 A0202: Set up a named domain list containing the domains in the first section
1939 of the configuration, for example:
1941 ==> domainlist reject_domains = list:of:domains:to:reject
1943 You can use this list in an ACL to reject any SMTP recipients in those
1944 domains. You can also give a customized error message, like this:
1946 ==> deny message = The domain $domain is no longer supported
1947 domains = +reject_domains
1949 If you also want to reject these domains in messages that are submitted
1950 from the command line (not using SMTP), you need to set up a router to
1955 domains = +reject_domains
1957 data = :fail: The domain $domain is no longer supported
1960 Q0203: How can I arrange to do my own qualification of non-fully-qualified
1961 domains, and then pass them on to the next router?
1963 A0203: If you have some list of domains that you want to qualify, you can do
1964 this using a redirect router. For example,
1969 data = ${quote:$local_part}@$domain.c.com
1971 This adds \".c.com"\ to any domain that matches \"*.a.b"\.
1972 If you want to do this in conjunction with a \%dnslookup%\ router, the
1973 \widen_domains\ option of that router may be another way of achieving
1977 Q0204: Every system has a \"nobody"\ account under which httpd etc run. I would
1978 like to know how to restrict mail which comes from that account to users
1981 A0204: Set up a first router like this:
1985 senders = nobody@your.domain
1986 domains = ! +local_domains
1988 data = :fail: Nobody may not mail off-site
1990 This assumes you have defined \+local_domains\ as in the default
1994 Q0205: How can I get Exim to deliver to me locally and everyone else at the same
1995 domain via SMTP to the MX record specified host?
1997 A0205: Create an \%accept%\ router to pick off the one address and pass it to
1998 an appropriate transport. Put this router before the one that does MX
2005 transport = local_delivery
2007 In the transport you will have to specify the \user\ option. An
2008 alternative way of doing this is to add a condition to the router that
2009 does MX lookups to make it skip your address. Subsequent routers can then
2010 deliver your address locally. You'll need a condition like this:
2013 ${if and {{eq{$domain}{dom.com}}{eq{$local_part}{me}}}{no}{yes}}
2016 Q0206: How can I get Exim to deliver certain domains to a different SMTP port
2019 A0206: You must set up a special \%smtp%\ transport, where you can specify the
2020 \port\ option, and then set up a router to route the domains to that
2021 transport. There are two possibilities for specifying the host:
2023 (1) If you use a \%manualroute%\ router, you can specify the local host
2024 in the router options. You must also set
2028 so that it does not object to sending to the local host.
2030 (2) If you use a router that cannot specify hosts (for example, an
2031 \%accept%\ router with appropriate conditions), you have to specify
2032 the host using the \hosts\ option of the transport. In this case,
2033 you must also set \allow_localhost\ on the transport.
2036 Q0207: Why does Exim lower-case the local-part of a non-local domain when
2039 A0207: Because \caseful_local_part\ is not set (in the default configuration)
2040 for the \%dnslookup%\ router. This does not matter because the local
2041 part takes no part in the routing, and the actual local part that is
2042 sent out in the RCPT command is always the original local part.
2046 3. ROUTING TO REMOTE HOSTS
2048 Q0301: What do \*lowest numbered MX record points to local host*\ and \*remote
2049 host address is the local host*\ mean?
2051 A0301: They mean exactly what they say. Exim expected to route an address to a
2052 remote host, but the IP address it obtained from a router was for the
2053 local host. If you really do want to send over TCP/IP to the local host
2054 (to a different version of Exim or another MTA, for example), see Q0206.
2056 More commonly, these errors arise when Exim thinks it is routing some
2057 foreign domain. For example, the router configuration causes Exim to
2058 look up the domain in the DNS, but when Exim examines the DNS output,
2059 either the lowest numbered MX record points at the local host, or there
2060 are no MX records, and the address record for the domain contains an
2061 IP address that belongs to the local host.
2063 There has been a rash of instances of domains being deliberately set up
2064 with MX records pointing to \"localhost"\ (or other names with A records
2065 that specify 127.0.0.1), which causes this behaviour. You can use the
2066 \ignore_target_hosts\ option to get Exim to ignore these records. The
2067 default contiguration does this. For more discussion, see Q0319. For
2070 (1) If the domain is meant to be handled as a local domain, there
2071 is a problem with the configuration, because it should not then have
2072 been looked up in the DNS. Check the \domains\ settings on your
2075 (2) If the domain is one for which the local host is providing a
2076 relaying service (called ``mail hubbing''), possibly as part of a
2077 firewall, you need to set up a router to tell Exim where to send
2078 messages addressed to this domain, because the DNS directs them to
2079 the local host. You should put a router like this one before the one
2080 that does DNS lookups:
2083 driver = manualroute
2084 transport = remote_smtp
2085 route_list = see discussion below
2087 The contents of the \route_list\ option depend on how many hosts you
2088 are hubbing for, and how their names are related to the domain name.
2089 Suppose the local host is a firewall, and all the domains in
2090 \(*.foo.bar)\ have MX records pointing to it, and each domain
2091 corresponds to a host of the same name. Then the setting could be
2093 ==> route_list = *.foo.bar $domain
2095 If there isn't a convenient relationship between the domain names
2096 and the host names, you either have to list each domain separately,
2097 or use a lookup expansion to look up the host from the domain, or
2098 put the routing information in a file and use the \route_data\
2099 option with a lookup expansion.
2101 (3) If neither (1) nor (2) is the case, the lowest numbered MX record or
2102 the address record for the domain should not be pointing to your
2103 host. You should arrange to get the DNS mended.
2106 Q0302: Why does Exim say \*all relevant MX records point to non-existent hosts*\
2107 when MX records point to IP addresses?
2109 A0302: MX records cannot point to IP addresses. They are defined to point to
2110 host names, so Exim always interprets them that way. (An IP address is a
2111 syntactically valid host name.) The DNS for the domain you are having
2112 problems with is misconfigured.
2114 However, it appears that more and more DNS zones are breaking the rules
2115 and putting IP addresses on the RHS of MX records. Exim follows the
2116 rules and rejects this, but other MTAs do support it, so the
2117 \allow_mx_to_ip\ was regretfully added at release 3.14 to permit this
2121 Q0303: How do I configure Exim to send all messages to a central server? I
2122 don't want to do any local deliveries at all on this host.
2124 A0303: Use this as your first and only router:
2126 ==> send_to_gateway:
2127 driver = manualroute
2128 transport = remote_smtp
2129 route_list = * central.server.host
2132 Q0304: How do I configure Exim to send all non-local mail to a gateway host?
2134 A0304: Replace the \%dnslookup%\ router in the default configuration with the
2137 ==> send_to_gateway:
2138 driver = manualroute
2139 domains = !+local_domains
2140 transport = remote_smtp
2141 route_list = * gate.way.host
2143 If there are several hosts you can send to, you can specify them as a
2144 colon-separated list.
2147 Q0305: How can I arrange for mail on my local network to be delivered directly
2148 to the relevant hosts, but all other mail to be sent to my ISP's mail
2149 server? The local hosts are all DNS-registered and behave like normal
2152 A0305: Set up a first router to pick off all the domains for your local
2153 network. There are several ways you might do this. For example
2157 transport = remote_smtp
2158 domains = *.mydomain.com
2160 This does a perfectly conventional DNS routing operation, but only for
2161 the domains that match \(*.mydomain.com)\. Follow this with a `smart
2165 driver = manualroute
2166 domains = !+local_domains
2167 transport = remote_smtp
2168 route_list = * mail.isp.net
2170 This routes any other non-local domains to the smart host.
2173 Q0306: How do I configure Exim to send all non-local mail to a central server
2174 if it cannot be immediately delivered by my host? I don't want to have
2175 queued mail waiting on my host.
2177 A0306: Add to the \%remote_smtp%\ transport the following:
2179 ==> fallback_hosts = central.server.name(s)
2181 If there are several names, they must be separated by colons.
2184 Q0307: The \route_list\ setting \"^foo$:^bar$ $domain"\ in a \%manualroute%\
2185 router does not work.
2187 A0307: The first thing in a \route_list\ item is a single pattern, not a list of
2188 patterns. You need to write that as \"^(foo|bar)$ $domain"\.
2189 Alternatively, you could use several items and write
2191 ==> route_list = foo $domain; bar $domain
2193 Note the semicolon separator. This is because the second thing in each
2194 item can itself be a list - of hosts.
2197 Q0308: I have a domain for which some local parts must be delivered locally,
2198 but the remainder are to be treated like any other remote addresses.
2200 A0308: One possible way of doing this is as follows: Assuming you are using a
2201 configuration that is similar to the default one, first exclude your
2202 domain from the first router by changing it to look like this:
2204 ==> non_special_remote:
2206 domains = ! +local_domains : ! special.domain
2207 transport = remote_smtp
2208 ignore_target_hosts = 127.0.0.0/8
2211 Then add a second router which handles the local parts that are not to
2212 be delivered locally:
2216 domains = special.domain
2217 local_parts = ! lsearch;/list/of/special/localparts
2218 transport = remote_smtp
2219 ignore_target_hosts = 127.0.0.0/8
2222 The remaining local parts will fall through to the remaining routers,
2223 which can delivery them locally.
2226 Q0309: How can I configure Exim on a firewall machine so that if mail arrives
2227 addressed to a domain whose MX points to the firewall, it is forwarded
2228 to the internal mail server, without having to have a list of all the
2231 A0309: As your first router, have the standard \%dnslookup%\ router from the
2232 default configuration, with the added option
2236 This will handle all domains whose lowest numbered MX records do not
2237 point to your host. Because of the \no_more\ setting, if it encounters
2238 an unknown domain, routing will fail. However, if it hits a domain whose
2239 lowest numbered MX points to your host, the \self\ option comes into
2240 play, and overrides \no_more\. The \"pass"\ setting causes it to pass
2241 the address on to the next router. (The default causes it to generate an
2244 The only non-local domains that reach the second router are those with
2245 MX records pointing to the local host. Set it up to send them to the
2246 internal mail server like this:
2249 driver = manualroute
2250 domains = ! +local_domains
2251 transport = remote_smtp
2252 route_list = * internal.server
2255 Q0310: If a DNS lookup returns no MX records why doesn't Exim just bin the
2258 A0310: If a DNS lookup returns no MXs, Exim looks for an address record, in
2259 accordance with the rules that are defined in the RFCs. If you want to
2260 break the rules, you can set \mx_domains\ in the \%dnslookup%\ router, but
2261 you will cut yourself off from those sites (and there still seem to be
2262 plenty) who do not set up MX records.
2265 Q0311: When a DNS lookup for MX records fails to complete, why doesn't Exim
2266 send the messsage to the host defined by the A record?
2268 A0311: The RFCs are quite clear on this. Only if it is known that there are no
2269 MX records is an MTA allowed to make use of the A record. When an MX
2270 lookup fails to complete, Exim does not know whether there are any MX
2271 records or not. There seem to be some name servers (or some
2272 configurations of some name servers) that give a ``server fail'' error when
2273 asked for a non-existent MX record. Exim uses standard resolver calls,
2274 which unfortunately do not distinguish between this case and a timeout,
2275 so all Exim can do is try again later.
2278 Q0312: Is it possible to use a conditional expression for the host item in a
2279 \route_list\ for \%manualroute%\ router? I tried the following, but it
2282 ==> route_list = * ${if match{$header_from:}{\N.*\.usa\.net$\N} \
2283 {<smarthost1>}{<smarthost2>}
2285 A0312: The problem is that the second item in \route_list\ contains white
2286 space, which means that it gets terminated prematurely. To avoid this,
2287 you must put the second item in quotes:
2289 ==> route_list = * "${if match{$header_from:}{\N.*\.usa\.net$\N} \
2290 {<smarthost1>}{<smarthost2>}}"
2293 Q0313: I send all external mail to a smart host, but this means that bad
2294 addresses also get passed to the smart host. Can I avoid this?
2296 A0313: Assuming you have DNS availability, set up a conventional \%dnslookup%\
2297 router to do the routing, but in the \%remote_smtp%\ transport set this:
2299 ==> hosts = your.smart.host
2302 This will override the hosts that the router finds so that everything
2303 goes to the smart host, but any non-existent domains will be failed by
2307 Q0314: I have a really annoying intermittent problem where attempts to mail to
2308 valid sites are rejected with \*unknown mail domain*\. This only happens a
2309 few times a day and there is no particular pattern to the sites it
2310 rejects. If I try to lookup the same domain a few minutes later then it
2313 A0314: This is almost certainly a problem with the DNS resolver or the the
2314 domain's name servers.
2316 (1) Have you linked Exim against the newest DNS resolver library that
2317 comes with Bind? If you are using SunOS4 that may be your problem, as
2318 the resolver that comes with that OS is known to be buggy and to give
2319 intermittent false negatives.
2321 (2) Effects like this are sometimes seen if a domain's name servers get
2322 out of step with each other.
2325 Q0315: I'd like route all mail with addresses that can't be resolved (the DNS
2326 lookup times out) to a relay machine.
2328 A0315: Set \pass_on_timeout\ on your \%dnslookup%\ router, and add below it a
2329 \%manualroute%\ router that routes all relevant domains to the relay.
2332 Q0316: I would like to forward all incoming email for a particular domain to
2333 another host via SMTP. Whereabouts would I configure that?
2335 A0316: Use this as your first router:
2338 driver = manualroute
2339 transport = remote_smtp
2340 route_list = the.particular.domain the.other.host
2342 You will also need to adjust the ACL for incoming SMTP so that this
2343 domain is accepted for relaying. If you are using the default
2344 configuration, there is a domain list called \relay_domains\ that is
2348 Q0317: What I'd like to do is have alternative smart hosts, where the one to be
2349 used is determined by which ISP I'm connected to.
2351 A0317: The simplest way to do this is to arrange for the name of the smart host
2352 du jour to be placed in a file when you connect, say \(/etc/smarthost)\.
2353 Then you can read this file from a \%manualroute%\ router like this:
2356 driver = manualroute
2357 transport = remote_smtp
2358 route_list = * ${readfile{/etc/smarthost}{}}
2360 The second argument of the \"readfile"\ item is a string that replaces
2361 any newline characters in the file (in this case, with nothing).
2362 By keeping the data out of the main configuration file, you avoid having
2363 to HUP the daemon when it changes.
2366 Q0318: Exim won't route to a host with no MX record.
2368 A0318: More than one thing may cause this.
2370 (1) Are you sure there really is no MX record? Sometimes a typo results
2371 in a malformed MX record in the zone file, in which case some name
2372 servers give a SERVFAIL error rather than NXDOMAIN. Exim has to treat
2373 this as a temporary error, so it can't go on to look for address records.
2374 You can check for this state using one of the DNS interrogation commands,
2375 such as \(nslookup)\, \(host)\, or \(dig)\.
2377 (2) Is there a wildcard MX record for \(your)\ domain? Is the
2378 \search_parents\ option on in your \%dnslookup%\ router? If the answer to
2379 both these questions is ``yes'', that is the cause of the problem. When
2380 the DNS resolver fails to find the MX record, it tries adding on your
2381 domain if \search_parents\ is true, and thereby finds your wildcard MX
2382 record. For example:
2384 . There is a wildcard MX record for \(*.a.b.c)\.
2386 . There is a host called \(x.y.z)\ that has an A record and no MX record.
2388 . Somebody on the host \(m.a.b.c)\ domain tries to mail to \(user@x.y.z)\.
2390 . Exim calls the DNS to look for an MX record for \(x.y.z)\.
2392 . The DNS doesn't find any MX record. Because \search_parents\ is true,
2393 it then tries searching the current host's parent domain, so it
2394 looks for \(x.y.z.a.b.c)\ and picks up the wildcard MX record.
2396 Setting \search_parents\ false makes this case work while retaining the
2397 wildcard MX record. However, anybody on the host \(m.a.b.c)\ who mails to
2398 \(user@n.a)\ (expecting it to go to \(user@n.a.b.c)\) now has a problem. The
2399 \widen_domains\ option of the \%dnslookup%\ router may be helpful in this
2403 Q0319: I have some mails on my queues that are sticking around longer than
2404 the retry time indicates they should. They are all getting frozen
2405 because some remote admin has set their MX record to 127.0.0.1.
2407 A0319: The admin in question is an idiot. Exim will always freeze such messages
2408 because they are apparently routed to the local host. To bounce these
2409 messages immediately, set
2411 ==> ignore_target_hosts = 127.0.0.1
2413 on the \%dnslookup%\ router. This causes Exim to completely ignore any hosts
2414 with that IP address. In fact, there are quite a number of IP addresses
2415 that should never be used. Here is a suggested configuration list for
2418 ==> # Don't allow domains whose single MX (or A) record is a
2419 # "special-use IPv4 address", as listed in RFC 3330.
2420 ignore_target_hosts = \
2421 # Hosts on "this network"; RFC 1700 (page 4) states that these
2422 # are only allowed as source addresses
2424 # Private networks, RFC 1918
2425 10.0.0.0/8 : 172.16.0.0/12 : 192.168.0.0/16 : \
2426 # Internet host loopback address, RFC 1700 (page 5)
2428 # "Link local" block
2430 # "TEST-NET" - should not appear on the public Internet
2432 # 6to4 relay anycast addresses, RFC 3068
2434 # Network interconnect device benchmark testing, RFC 2544
2436 # Multicast addresses, RFC 3171
2438 # Reserved for future use, RFC 1700 (page 4)
2442 Q0320: How can I arrange for all mail to \*user@some.domain*\ to be forwarded
2443 to \*user@other.domain*\?
2445 A0320: Put this as your first router:
2449 domains = some.domain
2450 data = ${quote:$local_part}@other.domain
2453 Q0321: How can I tell an Exim router to use only IPv4 or only IPv6 addresses
2454 when it finds both types in the DNS?
2456 A0321: You can do this by making it ignore the addresses you don't want. This
2457 example ignores all IPv6 addresses and all IPv4 addresses in the 127
2460 ==> ignore_target_hosts = <; 0000::0000/0 ; 127.0.0.0/8
2462 To ignore all IPv4 addresses, use
2464 ==> ignore_target_hosts = 0.0.0.0/0
2466 See Q0319 for a general discussion of \ignore_target_hosts\.
2469 Q0322: How can I reroute all messages bound for 192.168.10.0 and 10.0.0.0 to
2470 a specific mail server?
2472 A0322: That is an odd requirement. However, there is an obscure feature in
2473 Exim, originally implemented for packet radio people, that perhaps can
2474 help. Check out the \translate_ip_address\ generic router option.
2478 4. ROUTING FOR LOCAL DELIVERY
2480 Q0401: I need to have any mail for \(virt.dom.ain)\ that doesn't match one of the
2481 aliases in \(/usr/lib/aliases.virt)\ delivered to a particular address, for
2482 example, \(postmaster@virt.dom.ain)\.
2484 A0401: Adding an asterisk to a search type causes Exim to look up ``*'' when the
2485 normal lookup fails. So if your aliasing router is something like this:
2489 domains = virt.dom.ain
2490 data = ${lookup{$local_part}lsearch{/usr/lib/aliases.virt}}
2493 you should change \"lsearch"\ to \"lsearch*"\, and put this in the alias
2496 ==> *: postmaster@virt.dom.ain
2498 This solution has the feature that if there are several unknown
2499 addresses in the same message, only one copy gets sent to the
2500 postmaster, because of Exim's normal de-duplication rules.
2502 NOTE: This solution works only if there is also an entry for \(postmaster)\
2503 in the alias file, ultimately resolving to an address that is not in
2504 \(virt.dom.ain)\. See also Q0434.
2507 Q0402: How do I arrange for all incoming email for \(*@some.domain)\ to go into one
2508 pop3 mail account? The customer doesn't want to add a list of specific
2509 local parts to the system.
2511 A0402: Set up a special transport that writes to the mailbox like this:
2513 ==> special_transport:
2521 The file will be written as the user \"exim"\. Then arrange to route all
2522 mail for that domain to that transport, with a router like this:
2526 domains = some.domain
2527 transport = special_transport
2530 Q0403: How do I configure Exim to send messages for unknown local users to a
2533 A0403: Assuming you are using something like the default configuration, where
2534 local users are processed by the later routers, you should add the
2535 following router at the end:
2538 driver = manualroute
2539 transport = remote_smtp
2540 route_list = * server.host.name
2543 However, you should if possible try to verify that the user is known on
2544 the central server before accepting the message in the first place. This
2545 can be done by making use of Exim's ``call forward'' facility.
2548 Q0404: How can I arrange for messages submitted by (for example) Majordomo to
2549 be handled specially?
2551 A0404: You can use the \condition\ option on a router, with a setting such as
2553 ==> condition = ${if and {{eq {$sender_host_address}{}} \
2554 {eq {$sender_ident}{majordom}}} {yes}{no}}
2556 This first tests for a locally-submitted message, by ensuring there is
2557 no sending host address, and then it checks the identity of the user
2558 that ran the submitting process.
2561 Q0405: On a host that accepts mail for several domains, do I have to use fully
2562 qualified addresses in \(/etc/aliases)\ or do I have to set up an alias
2563 file for each domain?
2565 A0405: You can do it either way. The default aliasing router contains this line:
2567 ==> data = ${lookup{$local_part}lsearch{/etc/aliases}}
2569 which is what does the actual lookup. To make it look up the complete
2570 address instead of just the local part, use
2572 ==> data = ${lookup{$local_part@$domain}lsearch{/etc/aliases}}
2574 If you want to use a separate file for each domain, use
2576 ==> data = ${lookup{$local_part}lsearch{/etc/aliases/$domain}}
2579 Q0406: Some of my users are using the \(.forward)\ to pipe to a shell command which
2580 appends to the user's INBOX. How can I forbid this?
2582 A0406: If you allow your users to run shells in pipes, you cannot control which
2583 commands they run or which files they write to. However, you should point
2584 out to them that writing to an INBOX by arbitrary commands is not
2585 interlocked with the MTA and MUAs, and is liable to mess up the contents
2588 If a user simply wants to choose a specific file for the delivery of
2589 messages, this can be done by putting a file name in a \(.forward)\ file
2590 rather than using a pipe, or by using the \"save"\ command in an Exim
2593 You can set \forbid_pipe\ on the router, but that will prevent them from
2594 running any pipe commands at all. Alternatively, you can restrict which
2595 commands they may run in their pipes by setting the \allow_commands\
2596 and/or \restrict_to_path\ options in the \%address_pipe%\ transport.
2599 Q0407: How can I arrange for a default value when using a query-style lookup
2600 such as LDAP or NIS+ to handle aliases?
2602 A0407: Use a second query in the failure part of the original lookup, like
2605 ==> data = ${lookup ldap\
2606 {ldap://x.y.z/l=yvr?aliasaddress?sub?(&(mail=$local_part@$domain))}\
2610 {ldap://x.y.z/l=yvr?aliasaddress?sub?(&(mail=default@$domain))}}\
2613 Of course, if the default is a fixed value you can just include it
2617 Q0408: If I don't fully qualify the addresses in a virtual domain's alias file
2618 then mail to aliases which also match the local domain get delivered to
2621 A0408: Set the \qualify_preserve_domain\ option on the \%redirect%\ router.
2624 Q0409: I want mail for any local part at certain virtual domains to go
2625 to a single address for each domain.
2627 A0409: One way to to this is
2631 data = ${lookup{$domain}lsearch{/etc/virtual}}
2633 The \(/etc/virtual)\ file contains a list of domains and the addresses to
2634 which their mail should be sent. For example:
2636 ==> domain1: postmaster@some.where.else
2637 domain2: joe@xyz.plc
2639 If the number of domains is large, using a DBM or cdb file would be more
2640 efficient. If the lookup fails to find the domain in the file, the value
2641 of the \data\ option is empty, causing the router to decline.
2644 Q0410: How can I make Exim look in the alias NIS map instead of \(/etc/aliases)\?
2646 A0410: The default configuration does not use NIS (many hosts don't run it).
2647 You need to change this line in the \%system_aliases%\ router:
2649 ==> data = ${lookup{$local_part}lsearch{/etc/aliases}}
2653 ==> data = ${lookup{$local_part}nis{mail.aliases}}
2655 If you want to use \(/etc/aliases)\ as well as NIS, put this router (with
2656 a different name) before or after the default one, depending on which
2657 data source you want to take precedence.
2660 Q0411: Why will Exim deliver a message locally to any username that is longer
2661 than 8 characters as long as the first 8 characters match one of the
2664 A0411: The problem is in your operating system. Exim just calls the \^^getpwnam()^^\
2665 function to test a local part for being a local login name. It does not
2666 presume to guess the maximum length of user name for the underlying
2667 operating system. Many operating systems correctly reject names that are
2668 longer than the maximum length; yours is apparently deficient in this
2669 regard. To cope with such systems, Exim has an option called
2670 \max_user_name_length\ which you can set to the maximum allowed length.
2673 Q0412: Why am I seeing the error \*bad mode (100664) for /home/test/.forward*\?
2674 I've looked through the documentation but can't see anything to suggest
2675 that Exim has to do anything other than read the \(.forward)\ file.
2677 A0412: For security, Exim checks for mode bits that shouldn't be set, by
2678 default 022. You can change this by setting the \modemask\ option of the
2679 \%redirect%\ router that is handling \(.forward)\ files.
2682 Q0413: When a user's \(.forward)\ file is syntactially invalid, Exim defers
2683 delivery of all messages to that user, which sometimes include the
2684 user's own test messages. Can it be told to ignore the \(.forward)\ file
2685 and/or inform the user of the error?
2687 A0413: Setting \skip_syntax_errors\ on the redirect router causes syntax
2688 errors to be skipped. When dealing with users' \(.forward)\ files it is best
2689 to combine this with a setting of \syntax_errors_to\ in order to send
2690 a message about the error to the user. However, to avoid an infinite
2691 cascade of messages, you have to be able to send to an address that
2692 bypasses \(.forward)\ file processing. This can be done by including a
2693 router like this one
2698 transport = local_delivery
2701 before the \%redirect%\ router that handles \(.forward)\ files. This will
2702 do an ordinary local delivery without \(.forward)\ processing, if the
2703 local part is prefixed by \"real-"\. You can then set something like
2704 the following options on the \%redirect%\ router:
2706 ==> skip_syntax_errors
2707 syntax_errors_to = real-$local_part@$domain
2708 syntax_errors_text = "\
2709 This is an automatically generated message. An error has been \
2710 found\nin your .forward file. Details of the error are reported \
2711 below. While\nthis error persists, messages addressed to you will \
2712 get delivered into\nyour normal mailbox and you will receive a \
2713 copy of this message for\neach one."
2715 A final tidying setting to go with this is a rewriting rule that changes
2716 \"real-username"\ into just \"username"\ in the headers of the message:
2718 ==> \N^real-([^@]+)@your\.dom\.ain$\N $1@your.dom.ain h
2720 This means that users won't ever see the \"real-"\ prefix, unless they
2721 look at the ::Envelope-To:: header.
2724 Q0414: I have set \caseful_local_part\ on the routers that handle my local
2725 domain because my users have upper case letters in their login names,
2726 but incoming mail now has to use the correct case. Can I relax this
2729 A0414: If you really have to live with caseful user names but want incoming
2730 local parts to be caseless, then you have to maintain a file, indexed by
2731 the lower case forms, that gives the correct case for each login, like
2740 and at the start of the routers that handle your local domain, put one
2743 ==> set_case_router:
2745 data = ${lookup{${lc:$local_part}}lsearch{/the/file}}
2746 qualify_preserve_domain
2748 For efficiency, you should also set the \redirect_router\ option to cause
2749 processing of the changed address to begin at the next router. If you
2750 are otherwise using the default configuration, the setting would be
2752 ==> redirect_router = system_aliases
2754 If there are lots of users, then a DBM or cdb file would be more
2755 efficient than a linear search. If you are handling several domains,
2756 you will have to extend this configuration to cope appropriately.
2759 Q0415: Can I use my existing alias files and forward files as well as procmail
2760 and effectively drop in Exim in place of Sendmail ?
2762 A0415: Yes, as long as your alias and forward files don't assume that pipes are
2763 going to run under a shell. If they do, you either have to change them,
2764 or configure Exim to use a shell (which it doesn't by default).
2767 Q0416: What is quickest way to set up Exim so any message sent to a
2768 non-existing user would bounce back with a different message, based
2769 on the name of non-existing user?
2771 A0416: Place this router last, so that it catches any local addresses that
2772 are not otherwise handled:
2776 transport = non_exist_reply
2779 Then add the following transport to the transports section:
2781 ==> non_exist_reply:
2784 to = $sender_address
2785 subject = User does not exist
2786 text = You sent mail to $local_part. That's not a valid user here. \
2787 The subject was: $subject.
2789 If you want to pick up a message from a file, you can use the \file\
2790 option (use \file_expand\ if you want its contents expanded).
2793 Q0417: What do I need to do to make Exim handle \(/usr/ucb/vacation)\ processing
2794 automatically, so that people could just create a \(.vacation.msg)\ file in
2795 their home directory and not have to edit their \(.forward)\ file?
2797 A0417: Add a new router like this, immediately before the normal \%localuser%\
2803 require_files = $home/.vacation.msg
2804 transport = vacation_transport
2807 and a matching new transport like this:
2809 ==> vacation_transport:
2811 command = /usr/ucb/vacation $local_part
2813 However, some versions of \(/usr/ucb/vacation)\ do not work properly unless
2814 the DBM file(s) it uses are created in advance - it won't create them
2815 itself. You also need a way of removing them when the vacation is over.
2817 Another possibility is to use a fixed filter file which is run whenever
2818 \(.vacation.msg)\ exists, for example:
2823 require_files = $home/.vacation.msg
2824 file = /some/central/filter
2827 The filter file should use the \"if personal"\ check before sending mail,
2828 to avoid generating automatic responses to mailing lists. If sending a
2829 message is all that it does, this doesn't count as a ``significant''
2830 delivery, so the original message goes on to be delivered as normal.
2832 Yet another possibility is to make use of Exim's \%autoreply%\ transport,
2833 and not use \(/usr/ucb/vacation)\ at all.
2836 Q0418: I want to use a default entry in my alias file to handle unknown local
2837 parts, but it picks up the local parts that the aliases generate. For
2838 example, if the alias file is
2840 ==> luke.skywalker: luke
2844 then messages addressed to \/luke.skywalker/\ end up at \/postmaster/\.
2846 A0418: The default mechanism works best with virtual domains, where the
2847 generated address is not in the same domain. If you just want to pick up
2848 all unknown local parts and send them to postmaster, an easier way to do
2849 it is to put this as your last router:
2856 Another possibility is to put the redirect router for these aliases
2857 after all the other routers, so that local parts which are user names
2858 get picked off first. You will need to have two aliasing routers if
2859 there are some local parts (e.g. \/root/\) which are login names, but which
2860 you want to handle as aliases.
2863 Q0419: I have some obsolete domains which people have been warned not to use
2864 any more. How can I arrange to delete any mail that is sent to them?
2866 A0419: To reject them at SMTP time, with a customized error message, place
2867 statments like this in the ACL:
2869 ==> deny message = The domain $domain is obsolete
2870 domains = lsearch;/etc/exim/obsolete.domains
2872 For messages that don't arrive over SMTP, you can use a router like
2873 this to bounce them:
2877 domains = lsearch;/etc/exim/obsolete.domains
2879 data = :fail: the domain $domain is obsolete
2881 If you just want to throw away mail to those domains, accept them at
2882 SMTP time, and use a router like this:
2885 domains = lsearch;/etc/exim/obsolete.domains
2889 Q0420: How can I arrange that mail addressed to \(anything@something.mydomain.com)\
2890 gets delivered to \(something@mydomain.com)\?
2892 A0420: Set up a router like this:
2894 ==> user_from_domain:
2896 data = ${if match{$domain}{\N^(.+)\.mydomain\.com$\N}\
2900 Q0421: I can't get a regular expression to work in a \local_parts\ option on
2903 A0421: Have you remembered to protect any backslash and dollar characters in
2904 your regex from unwanted expansion? The easiest way is to use the
2905 \"@\N"\ facility, like this:
2907 ==> local_parts = \N^0740\d{6}\N
2910 Q0422: How can I arrange for all addresses in a group of domains \(*.example.com)\
2911 to share the same alias file? I have a number of such groups.
2913 A0422: For a single group you could just hard wire the file name into a router
2916 ==> domains = *.example.com
2918 set, to restrict it to the relevant domains. For a number of such groups
2919 you can create a file containing the domains, like this:
2921 ==> *.example1.com example1.com
2922 *.example2.com example2.com
2925 Then create a router like this
2929 domains = partial-lsearch;/that/file
2930 data = ${lookup{$local_part}lsearch*{/etc/aliases.d/$domain_data}}
2932 The variable \$domain_data$\ contains the data that was looked up when the
2933 \domains\ option was matched, i.e. \"example1.com"\, \"example2.com"\, etc.
2937 Q0423: Some of our users have no home directories; the field in the password
2938 file contains \(/no/home/dir)\. This causes the error \*failed to stat
2939 /no/home/dir (No such file or directory)*\ when Exim tries to look for a
2940 \(.forward file)\, and the delivery is deferred.
2942 A0423: There are two issues involved here:
2944 (1) With the default configuration, you are asking Exim to check for a
2945 \(.forward)\ file in the user's home directory. If no file is found,
2946 Exim tries to \^^stat()^^\ the home directory. This is so that it will
2947 notice a missing NFS home directory, and not treat it as if the
2948 \(.forward)\ file did not exist. This \^^stat()^^\ is failing when the
2949 home directory really doesn't exist. You should arrange for the
2950 \%userforward%\ router not to run for these special users, by adding
2953 ==> condition = ${if eq {$home}{/no/home/dir}{no}{yes}}
2955 (2) If you use \check_local_user\ on another router to route to a local
2956 transport (again, this is what is in the default configuration), you
2957 will also have to specify a current directory for the transport, because
2958 by default it makes the home directory current. This is easily done by
2961 ==> current_directory = /
2965 ==> transport_current_directory = /
2967 to the router. Or you can add \home_directory\ to the transport, because
2968 the current directory defaults to the home directory.
2971 Q0424: How can I disable Exim's de-duplication features? I want it to do two
2972 deliveries if two different aliases expand to the same address.
2974 A0424: This is not possible. Duplication has other ramifications other than
2975 just (in)convenience. Consider:
2977 . Message is addressed to A and to B.
2979 . Both A and B are aliased to C.
2981 . Without de-duplication, two deliveries to C are scheduled.
2983 . One delivery happens, Exim records that it has delivered the message
2986 . The next delivery fails (C's mailbox is over quota, say).
2988 Next time round, Exim wants to know if it has already delivered to C or
2989 not, before scheduling a new delivery. Has it? Obviously, if duplicate
2990 deliveries are supported, it has to remember not only that it has
2991 delivered to C but also the ``history'' of how that delivery happened - in
2992 effect an ancestry list back to the original envelope address. This it
2993 does not do, and changing it to work in that way would be a lot of work
2996 The best way to get duplicate deliveries if you want them is not to use
2997 aliases, but to route the addresses directly to a transport, e.g.
3001 local_parts = lsearch;/etc/list/of/special/local/parts
3002 transport = local_delivery
3006 Q0425: My users' mailboxes are distributed between several servers according to
3007 the first letter of the user name. All the servers receive incoming mail
3008 at random. I would like to have the same configuration file for all the
3009 servers, which does local delivery for the mailboxes it holds, and sends
3010 other addresses to the correct other server. Is this possible?
3012 A0425: It is easiest if you arrange for all the users to have password entries
3013 on all the servers. This means that non-existent users can be detected
3014 at the first server they reach. Set up a file containing a mapping from
3015 the first letter of the user names to the servers where their mailboxes
3016 are held. For example:
3023 Before the normal \%localuser%\ router, place the following router:
3026 driver = manualroute
3028 transport = remote_smtp
3029 route_list = * ${lookup{${substr_0_1:$local_part}}lsearch{/etc/mapfile}}
3032 This router checks for a local account, then looks up the host from the
3033 first character of the local part. If the host is not the local host,
3034 the address is routed to the \%remote_smtp%\ transport, and sent to the
3035 correct host. If the host is the local host, the \self\ option causes
3036 the router to pass the address to the next router, which does a local
3039 The router is skipped for local parts that are not the names of local
3040 users, and so these addresses fail.
3043 Q0426: One of the things I want to set up is for \(anything@onedomain)\ to forward
3044 to \(anything@anotherdomain)\. I tried adding \($local_part@anotherdomain)\ to
3045 my aliases but it did not expand - it sent it to that literal address.
3047 A0426: If you want to do it that way, you can use the \"expand"\ operator on
3048 the lookup used in the data option of the redirect router. For example:
3050 ==> data = ${expand:${lookup{$local_part}lsearch*{/etc/aliases}}}
3052 Another approach is to use a router like this:
3057 data = $local_part@anotherdomain
3059 The value of \data\ can, of course, be more complicated, involving
3060 lookups etc. if you have lots of different cases.
3063 Q0427: How can I have an address looked up in two different alias files, and
3064 delivered to all the addresses that are found?
3066 A0427: Use a router like this:
3070 data = ${lookup{$local_part}lsearch{/etc/aliases1}\
3071 {$value${lookup{$local_part}lsearch{/etc/aliases2}{,$value}}}\
3072 {${lookup{$local_part}lsearch{/etc/aliases2}{$value}fail}}}\
3074 If the first lookup succeeds, the result is its data, followed by the
3075 data from the second lookup, if any, separated by a comma. If the first
3076 lookup fails, the result is the data from the third lookup (which also
3077 looks in the second file), but if this also fails, the entire expansion
3078 is forced to fail, thereby causing the router to decline.
3080 Another approach is to use two routers, with the first re-generating the
3081 original local part when it succeeds. This won't get processed by the
3082 same router again. For example:
3086 data = ${lookup{$local_part}lsearch{/etc/aliases1}{$value,$local_part}}
3089 data = ${lookup{$local_part}lsearch{/etc/aliases2}}
3091 This scales more easily to three or more alias files.
3094 Q0428: I've converted from Sendmail, and I notice that Exim doesn't make use
3095 of the \"owner-"\ entries in my alias file to change the sender address in
3096 outgoing messages to a mailing list.
3098 A0428: If you have an alias file with entries like this:
3100 ==> somelist: a@b, c@d, ...
3101 owner-somelist: postmaster
3103 Sendmail assumes that the second entry specifies a new sender address
3104 for the first. Exim does not make this assumption. However, you can make
3105 it take the same action, by adding
3107 ==> errors_to = owner-$local_part@whatever.domain
3109 to the configuration for your aliasing router. This is fail-safe,
3110 because Exim verifies a new sender address before using it. Thus, the
3111 change of sender address occurs only when the owner entry exists.
3114 Q0429: I would like to deliver mail addressed to a given domain to local
3115 mailboxes, but also to generate messages to the envelope senders.
3117 A0429: You can do this with an ``unseen'' router and an \%autoreply%\ transport,
3118 along the following lines:
3124 domains = <domains you want to do this for>
3125 condition = ${if eq{$sender_address}{}{no}{yes}}
3126 transport = warning_t
3130 Place this router immediately before the normal \%localuser%\ router. The
3131 \unseen\ option means that the address is still passed on to the next
3132 router. The transport is configured like this:
3137 file = /usr/local/mail/warning.txt
3139 from = postmaster@your.domain
3140 to = $sender_address
3142 subject = Re: Your mail to $local_part@$domain
3144 Note the use of the \condition\ option to avoid attempting to send a
3145 message when there is no sender (that is, when the incoming message is a
3146 bounce message). You can of course extend this to include other
3147 conditions. If you want to log the sending of messages, you can add
3149 ==> log = /some/file
3151 to the transport and also make use of the \once\ option if you want to
3152 send only one message to each sender.
3155 Q0430: Whenever Exim tries to route a local address, it gives a permission
3156 denied error for the \(.forward)\ file, like this:
3158 ==> 1998-08-10 16:55:32 0z5y2W-0000B8-00 == xxxx@yyy.zzz <xxxx@yyy.zz>
3159 D=userforward defer (-1): failed to open /home/xxxx/.forward
3160 (userforward router): Permission denied (euid=1234 egid=101)
3162 A0430: Have you remembered to make Exim setuid \/root/\?
3165 Q0431: How do I configure Exim to allow arbitrary extensions in local parts, of
3166 the form \/+extension/\?
3168 A0431: Add this pre-condition to the relevant router:
3170 ==> local_part_suffix = +*
3172 If you want the extensions to be optional, also add the option
3174 ==> local_part_suffix_optional
3176 When the router runs, \$local_part$\ contains the local part with the
3177 extension removed, and the extension (if any) is in \$local_part_suffix$\.
3178 If you have set \check_local_user\, the test is carried out after the
3179 extension is removed.
3182 Q0432: I use NIS for my user data. How can I stop Exim rejecting mail when my
3183 NIS servers are being restarted?
3185 A0432: Exim doesn't know that you are using NIS; it just calls the \^^getpwnam()^^\
3186 function, which is routed by nsswitch. Unfortunately, \^^getpwnam()^^\
3187 was never designed to be routed through NIS, and it returns NULL if the
3188 entry is not found or if the connection to the NIS server fails. This
3189 means that Exim cannot tell the difference between ``no such user'' and
3192 Crutches to help with this problem are \finduser_retries\ in Exim, and
3193 \^nscd^\ on the Unix side, but they are not perfect, and mail can still
3194 be lost. However, Nico Erfurth pointed out that you can create a router
3195 for Exim that tests for the availability of NIS, and force a defer if
3200 data = ${lookup {$local_part} nis {passwd}{}}
3202 This should be placed before any router that makes any use of NIS,
3203 typically at the start of your local routers. How does it work? If
3204 your NIS server is reachable, the lookup will take place, and whether it
3205 succeeds or fails, the result is an empty strting. This causes the
3206 router to decline, and the address is passed to the following routers.
3207 If your NIS server is down, the lookup defers, and this causes the
3208 router to defer. A verification of an incoming address gets a temporary
3209 rejection, and a delivery is deferred till later.
3212 Q0433: How can I arrange for a single address to be processed by \*both*\
3213 \%redirect%\ \*and*\ \%accept%\?
3215 A0433: Check out the \unseen\ option.
3218 Q0434: How can I redirect all local parts that are not in my system aliases to
3219 a single address? I tried using an asterisk in the system alias file
3220 with an \"lsearch*"\ lookup, but that send \*all*\ messages to the
3223 A0434: If your alias file generates addresses in the local domain, they are
3224 also processed as a potential aliases. For example, suppose this is your
3231 The local part \/caesar/\ is aliased to \/jc/\, but that address is then
3232 reprocessed by the routers. As the address is in the local domain, the
3233 alias file is again consulted, and this time the default matches. In
3234 fact after the second aliasing, \/brutus/\ is also processed again from
3235 the start, and is aliased to itself. However, this happens only once,
3236 because the next time, Exim notices that the aliasing router has already
3237 processed \/brutus/\, so the router is skipped in order to avoid
3240 There are several ways of solving this problem; which one you use
3241 depends on your aliasing data.
3243 (1) If the result of aliasing is always a local user name, that is,
3244 aliasing never generates another alias, you can use the
3245 \redirect_router\ option on the router to specify that processing
3246 the generated addresses must start at the next router. For example:
3248 ==> redirect_router = userforward
3250 assuming that the next router is called \%userforward%\. This
3251 ensures that there is at most one pass through the aliasing router.
3253 (2) If you cannot rely on aliases generating non-aliases, it is often
3254 easier not to use a default alias, but instead to place a router
3255 such as the one below after all the other local routers (for the
3261 data = brutus@$domain
3263 Note that the default aliasing technique works more successfully for
3264 virtual domains (see Q0401) because the generated address for the
3265 default is not usually in the same virtual domain as the incoming
3269 Q0435: My alias file contains fully qualified addresses as keys, and some
3270 wildcard domains in the form @foo.bar. Can Exim handle these?
3272 A0435: You can handle fully qualified addresses with this router:
3274 ==> qualified_aliases:
3276 data = ${lookup{$local_part@$domain}lsearch{/etc/aliases}}
3278 (Add any other options you need for the \%redirect%\ router.) Place this
3279 router either before or after the default aliases router that looks up
3280 the local part only. (Or, if you have no unqualified aliases, replace
3281 the default router.)
3283 To handle wildcards in the form @foo.bar you will need yet another
3284 router. (Wildcards of the form *@foo.bar can be handled by an lsearch*@
3285 lookup.) Something like this:
3287 ==> wildcard_aliases:
3289 data = ${lookup{@$domain}lsearch{/etc/aliases}}
3291 Place this after the routers that handle the more specific aliases.
3297 Q0501: My filter isn't working. How can I test it?
3299 A0501: Use the \-bf-\ option (\-bF-\ for a system filter) to test the basic operation
3300 of your filter. You can request debugging information for filtering only
3301 by adding \"-d-all+filter"\ to the command.
3304 Q0502: What I really need is the ability to obtain the result of a pipe
3305 command so that I can filter externally and redirect internally. Is
3308 A0502: The result of a pipe command is not available to a filter, because Exim
3309 does not run any actual deliveries while filtering. It just sets up
3310 deliveries at this time. They all actually happen later. If you want to
3311 run pipes and examine their results, you need to set up a single
3312 delivery to a delivery agent such as \^procmail^\ which provides this kind
3315 An possible alternative is to use the \"${run"\ expansion item to run an
3316 external command while filtering. In this case, you can make use of some
3317 of the results of the command.
3320 Q0503: I received a message with a ::Subject:: line that contained a non-printing
3321 character (a carriage return). This messed up my filter file. Is there a
3322 way to get round it?
3324 A0503: Instead of \"$h_subject:"\ use \"${escape:$h_subject:}"\
3327 Q0504: I want to search for \"$"\ in the subject line, but I can't seem to get
3330 A0504: Try one of these:
3332 ==> if $h_subject: contains \$ then ...
3333 if $h_subject: contains "\\$" then ...
3336 Q0505: My problem is that Exim replaces \$local_part$\ with an empty string in the
3337 system filtering. What's wrong or what did I miss?
3339 A0505: A message may have many recipients. The system filter is run just once
3340 at the start of a delivery attempt. Consequently, it does not make sense
3341 to set \$local_part$\. Which recipient should it be set to? However, you
3342 can access all the recipients from a system filter via the variable
3343 called \$recipients$\.
3346 Q0506: Using \$recipients$\ in a system filter gives me another problem: how can
3347 I do a string lookup if \$recipients$\ is a list of addresses?
3349 A0506: Check out the section of the filter specification called \*Testing a list of
3350 addresses*\. If that doesn't help, you may have to resort to calling an
3351 embedded Perl interpreter - but that is expensive.
3354 Q0507: What are the main differences between using an Exim filter and using
3357 A0507: Exim filters and \^procmail^\ provide different facilities. Exim filters run
3358 at routing time, before any deliveries are done. A filter is like a
3359 ``\(.forward)\ file with conditions''. One of the benefits is de-duplication.
3360 Another is that if you forward, you are forwarding the original message.
3362 However, this does mean that pipes etc. are not run at filtering time,
3363 nor can you change the headers, because the message may have other
3364 recipients and Exim keeps only a single set of headers.
3366 \^procmail^\ runs at delivery time. This is for one recipient only, and so
3367 it can change headers, run pipes and check the results, etc. However, if
3368 it wants to forward, it has to create a new message containing a copy
3369 of the original message.
3371 It's your choice as to which of these you use. You can of course use
3375 Q0508: How can I allow the use of relative paths in users' filter files when
3376 the directories concerned are not available from the password data?
3378 A0508: You need to be running Exim 4.11 or later. You can then specify a value
3379 for \$home$\ by setting the router_home_directory option on the
3380 \%redirect%\ router.
3382 For earlier releases, there is no way to specify the value of \$home$\
3383 for a \%redirect%\ router; it either comes from the password data as a
3384 result of \check_local_user\, or is unset.
3387 Q0509: How can I set up a filter file to detect and block virus attachments?
3389 A0509: Exim's filter facilities aren't powerful enough to do much more than
3390 very crude testing. Most people that want virus checking are nowadays
3391 using one of the separate scanning programs such as \^exiscan^\ (see
3392 \?http://duncanthrax.net/exiscan/?\). There is some further information
3393 about scanning with Exim via \?http://www.timj.co.uk/linux/exim.php?\.
3396 Q0510: Is it possible to write code for scanning messages in Python?
3398 A0510: \^elspy^\ is a layer of glue code that enables you to write Python code
3399 to scan email messages at SMTP time. \^elspy^\ also includes a small
3400 Python library with common mail-scanning tools, including an interface
3401 to SpamAssassin and a simple but effective virus detector. You can
3402 optain \^elspy^\ from \?http://elspy.sourceforge.net/?\.
3405 Q0511: Whenever my system filter uses a \mail\ command to send a message, I get
3406 the error \*User 0 set for address_reply transport is on the never_users
3407 list*\. What does this mean?
3409 A0511: The system filter runs as \/root/\ in Exim 4, unless you set
3410 \system_filter_user\ to specify otherwise. When you set up a delivery
3411 direct from a system filter (an autoreply is a special kind of
3412 ``delivery'') the transport runs as the same user, unless it has a
3413 \user\ setting of its own. Normally, deliveries are not allowed to run
3414 as \/root/\ as a security precaution; this is implemented by the
3415 \never_users\ option.
3417 The easiest solution is to add this to your configuration:
3419 ==> system_filter_user = exim
3421 The system filter then runs as \/exim/\ instead of \/root/\.
3422 Alternatively, you can arrange for autoreplies from the system filter to
3423 use a special transport of their own, and set the \user\ option on that
3427 Q0512: I'm trying to reference the ::Envelope-To:: header in my filter, but
3428 \$h_envelope-to:$\ is always empty.
3430 A0512: ::Envelope-To:: is added at delivery time, by the transport. Therefore,
3431 the header doesn't exist at filter time. In a user filter, the values
3432 you probably want are in \$original_local_part$\ and
3433 \$original_domain$\. In a system filter, the complete list of all
3434 envelope recipients is in \$recipients$\.
3437 Q0513: I want my system filter to freeze all mails greater than 500K in size,
3438 but to exclude those to a specific domain. However, I don't seem to be
3439 able to use \$domain$\ in a system filter.
3441 A0513: You cannot do this in a system filter, because a single message may have
3442 multiple recipients, some in the special domain, and some not. That is
3443 also the reason why \$domain$\ is not set in a system filter.
3445 If you want to take actions on a per-recipient basis, you have to do it
3446 in a router. However, freezing is not appropriate, because freezing
3447 stops all deliveries. You could, however, delay delivery to all but the
3448 special domains by using something like this:
3450 ==> delay_if_too_big:
3452 domains = !the.special.domain
3453 condition = ${if >{$message_size}{500K}{yes}{no}}
3455 data = :defer: message too big.
3457 However, there isn't an easy way of ``releasing'' such messages at
3461 Q0514: When I try to send to two addresses I get an error in the filter
3462 file \*malformed address: , e@fgh.com may not follow a@bcd.com*\. What
3467 ==> deliver "a@bcd.com, e@fgh.com"
3469 in your filter? If so, that is your problem. You should have
3471 ==> deliver a@bcd.com
3474 Each \deliver\ command expects just one address.
3480 Q0601: What does the error \*Neither the xxx router nor the yyy transport set
3481 a uid for local delivery of...*\ mean?
3483 A0601: Whenever Exim does a local delivery, it runs a process under a specific
3484 user and group id (uid and gid). For deliveries into mailboxes, and to
3485 pipes and files set up by forwarding, it normally picks up the uid/gid
3486 of the receiving user. However, if an address is directed to a pipe or a
3487 file by some other means, such an entry in the system alias file of the
3490 ==> majordomo: |/local/mail/majordomo ...
3492 then Exim has to be told what uid/gid to use for the delivery. This can
3493 be done either on the routerr that handles the address, or on the
3494 transport that actually does the delivery. If a pipe is going to run a
3495 setuid program, then it doesn't matter what uid Exim starts it out with,
3496 and so the most straightforward thing is to put
3500 on either the router or the transport. A setting on the transport
3501 overrides a setting on the router, so if the same transport is being
3502 used with several routers, you should set the user on it only if you
3503 want the same uid to be used in all cases.
3505 In the default configuration, the transports used for file and pipe
3506 deliveries are the ones called \address_file\ and \address_pipe\. You
3507 can specify different transports by setting, for example,
3509 ==> pipe_transport = special_pipe_transport
3511 on the \%system_aliases%\ router. Then you can set up \%special_pipe_transport%\
3513 ==> special_pipe_transport:
3517 which will be used only for pipe deliveries from that one router.
3518 What you put for the ???? is up to you, and depends on the particular
3522 Q0602: Exim keeps crashing with segmentation errors (signal 11 or 139) during
3523 delivery. This seems to happen when it is about to contact a remote
3524 host or when a delivery is deferred.
3526 A0602: This could be a problem with Exim's databases. Try running a delivery
3527 with debugging turned on. If the last line of the debug output is
3528 something like this:
3530 ==> locked /var/spool/exim/db/retry.lockfile
3532 the crash is happening inside the DBM library. Check that your DBM
3533 library is correctly installed. In particular, if you have installed a
3534 second DBM library onto a system that already had one, check that its
3535 version of \(ndbm.h)\ is being seen first. For example, if the new
3536 version is in \(/usr/local/include)\, check that there isn't another
3537 version in \(/usr/include)\. If you are using Berkeley db, you can set
3541 in your \(Local/Makefile)\ to avoid using \(ndbm.h)\ altogether. This is
3542 particularly relevant for version 2 (or later) of Berkeley db, because
3543 no \(ndbm.h)\ file is distributed with it. Another thing you can try is
3546 ==> exim_dumpdb /var/spool/exim retry
3548 to see if it also crashes, or build the \^test_dbfn^\ tool and fiddle
3549 around with it. If both fail, it is most almost certainly a problem with
3550 your DBM library. You could try to update it, or force Exim to use
3551 another library. See the file \(doc/dbm.discuss.txt)\ for hints about
3555 Q0603: How can mails that are being routed through routers that do not set
3556 \check_local_user\ be delivered under the uid of the recipient?
3558 A0603: Q0601 contains background information on this. If you are using, say, an
3559 alias file to direct messages to specific mailboxes, you can use
3560 the \user\ option on either the router or the transport to set the uid.
3561 What you put in the setting depends on how the required uid is to be
3562 found. It could be looked up in a file or computed somehow from the
3563 local part, for example.
3566 Q0604: I want to use MMDF-style mailboxes. How can I get Exim to append the
3567 ctrl-A characters that separate indvidual emails?
3569 A0604: Set the \message_suffix\ option in the \%appendfile%\ transport. In fact,
3570 for MMDF mailboxes you need a prefix as well as a suffix to get it
3571 working right, so your transport should contain these settings:
3573 ==> message_prefix = "\1\1\1\1\n"
3574 message_suffix = "\1\1\1\1\n"
3576 Also, you need to change the \check_string\ and \escape_string\ settings so
3577 that the escaping happens for lines in the message that happen to begin
3578 with the MMDF prefix or suffix string, rather than ``From'' (the default):
3580 ==> check_string = "\1\1\1\1\n"
3581 escape_string = "\1\1\1\1 \n"
3583 Adding a space to the line is sufficient to prevent it being taken as a
3587 Q0605: If a user's mailbox is over quota, is there a way for me to set it up so
3588 that the mail bounces to the sender and is not stored in the mail queue?
3590 A0605: In the retry section of the configuration, put
3592 ==> *@your.dom.ain quota
3594 That is, provide no retry timings for over quota errors. They will then
3595 bounce immediately. Alternatively, you can set up retries for a short
3596 time only, or use something like this:
3598 ==> *@your.dom.ain quota_7d
3599 *@your.dom.ain quota F,2h,15m; F,3d,1h
3601 which bounces immediately if the user's mailbox hasn't been read for 7
3602 days, but otherwise tries for up to 3 days after the first quota
3606 Q0606: I'm using tmail to do local deliveries, but when I turned on the
3607 \use_crlf\ option on the \%pipe%\ transport (tmail prefers \"@\r@\n"\
3608 terminations) message bodies started to vanish.
3610 A0606: You need to unset the \mesage_prefix\ option, or change it so that its
3611 default \"@\n"\ terminator becomes \"@\r@\n"\. For example, the
3614 ==> local_delivery_mbx:
3616 command = /usr/local/bin/tmail $local_part
3618 current_directory = /
3622 The reason for this is as follows: tmail uses the line terminator on
3623 the first line it sees to determine whether lines are terminated by
3624 \"@\r@\n"\ or \"@\n"\. If the latter, it moans to stderr and changes subsequent
3625 \"@\n"\ terminators to \"@\r@\n"\. The default setting of the \message_prefix\
3626 option is \"From ...@\n"\, and this is unaffected by the \use_crlf\ option.
3627 If you don't change this, tmail sees the first line terminated by
3628 \"@\n"\ and prepends \"@\r"\ to the \"@\n"\ terminator on all subsequent
3629 lines. However, if \use_crlf\ is set, Exim makes all other lines
3630 \"@\r@\n"\ terminated, leading to doubled \"@\r@\r@\n"\ lines and
3631 corrupt mbx mailboxes.
3634 Q0607: When I activate ``return receipt'' for example in Netscape Mailbox
3635 sending options, then I get an error message from Exim... something
3636 like \*not supported*\. Can I activate delivery confirmations?
3638 A0607: Exim does not support any kind of delivery notification.
3640 (1) You can configure it to recognize headers such as
3641 \Return-receipt-to:\ if you wish.
3643 (2) Some people want MSN (message status notification). Such services
3644 are implemented in MUAs, and don't impact on the MTA at all.
3646 (3) I investigated the RFCs which describe the DSN (delivery status
3647 notification) system. However, I was unable to specify any sensible way
3648 of actually doing anything with the data. There were comments on the
3649 mailing list at the time; many people, including me, conclude that DSN
3650 is in practice unworkable. The killer problem is with forwarding and
3651 aliasing. Do you propagate the DSN data with the generated addresses?
3652 Do you send back a ``reached end of the DSN world'' or ``expanded'' message?
3653 Do you do this differently for different kinds of aliasing/forwarding?
3654 For a user who has a \(.forward)\ file with a single address in, this
3655 might seem easy - just propagate the data. But what if there are several
3656 forwardings? If you propagate the DSN data, the sender may get back
3657 several DSN messages - and should the sender really know about the
3658 detail of the receiver's forwarding arrangements? There isn't really
3659 any way to distinguish between a \(.forward)\ file that is forwarding
3660 and one that is a mini mailing list. And so on, and so on. There are so
3661 many questions that don't have obvious answers.
3664 Q0608: What does the message \*retry time not reached [for any host]*\ on the log
3665 mean? Why won't Exim try to deliver the message?
3667 A0608: That is not an error. It means exactly what it says. A previous attempt
3668 to deliver to that address failed with a temporary error, and Exim
3669 computed the earliest time at which to try again. This can apply to
3670 local as well as to remote deliveries. For remote deliveries, each host
3671 (if there are several) has its own retry time.
3673 If you are running on a dial-up host, the rest of this answer probably
3674 does not apply to you. Go and read Q1404 instead. If your host is
3675 permanently online, read on...
3677 Some MTAs have a retrying schedule for each message. Exim does not work
3678 like this. Retry timing is normally host-based for remote deliveries and
3679 address-based for local deliveries. (There are some exceptions for certain
3680 kinds of remote failure - see \*Errors in outgoing SMTP*\ in the manual.)
3682 If a new message arrives for a failing address and the retry time has
3683 not yet arrived, Exim will log \*retry time not reached*\ and leave the
3684 message on the queue, without attempting delivery. Similarly, if a queue
3685 runner notices the message before the time to retry has arrived, it
3686 writes the same log entry. When the retry time has past, Exim attempts
3687 delivery at the next queue run. If you want to know when that will be,
3688 run the exinext utility on the address, for example:
3690 ==> exinext user@some.domain
3692 You can suppress these messages on the log by including \"-retry_defer"\
3693 in the setting of \log_selector\. You can force a delivery attempt on a
3694 specific message (overriding the retry time) by means of the -M option:
3696 ==> exim -M 10hCET-0000Bf-00
3698 If you want to do this for the entire queue, use the \-qf-\ option.
3701 Q0609: Exim seems to be sending the same message twice, according to the log,
3702 although there is a difference in capitalization of the local part of
3705 A0609: That is correct. The RFCs are explicit in stating that capitalization
3706 matters for local parts. For remote domains, Exim is not entitled to
3707 assume case independence of local parts. I know, it is utterly silly,
3708 and it causes a lot of grief, but that's what the rules say. Here is a
3709 quote from RFC 2821:
3711 ... a command verb, an argument value other than a mailbox local-part,
3712 and free form text MAY be encoded in upper case, lower case, or any
3713 mixture of upper and lower case with no impact on its meaning. This
3714 is NOT true of a mailbox local-part. The local-part of a mailbox
3715 MUST BE treated as case sensitive. Therefore, SMTP implementations
3716 MUST take care to preserve the case of mailbox local-parts. Mailbox
3717 domains are not case sensitive. In particular, for some hosts the
3718 user "smith" is different from the user "Smith". However, exploiting
3719 the case sensitivity of mailbox local-parts impedes interoperability
3723 Q0610: How can I force the next retry time for a host to be now?
3725 A0610: You can change the retry time with the \^exim_fixdb^\ utility, but its
3726 interface is very clumsy. If you have a message for the host on the
3727 queue, the simplest thing to do is to force a delivery with the \-M-\
3728 command line option. If delivery succeeds, the retry data will get
3729 cleared. If the host is past the cutoff time, so that messages are
3730 bouncing immediately without trying a delivery, you can use \-odq-\ to
3731 put a message on the queue without a delivery attempt, and then use
3735 Q0611: I set up \"|/bin/grep Subject|/usr/bin/smbclient -M <netbiosname>"\ as an
3736 alias but it doesn't work.
3738 A0611: That is a shell command line. Exim does not run pipe commands under a
3739 shell by default (for added security - and it saves a process). You
3742 ==> "|/bin/sh -c '/bin/grep Subject|/usr/bin/smbclient -M <netbiosname>'"
3745 Q0612: Why does the \%pipe%\ transport add a line starting with \">From"\ to
3748 A0612: Actually, it adds a line starting with \"From"\ followed by a space.
3749 This is commonly referred to as the \"From_"\ line, to emphasize the
3750 fact that \"From"\ is followed by a space and not a colon. This is a
3751 pseudo-header line that contains the envelope sender address and the
3752 time of delivery. It originated as a separator line in Berkeley format
3753 mailboxes, but is also used in other contexts. (And yes, it is often
3754 confused with the ::From:: header line, and this causes a lot of grief.
3755 The use of \"From_"\ was one of the really bad email design decisions.)
3757 Exim's \%pipe%\ transport adds this pseudo-header line by default
3758 because \(/usr/ucb/vacation)\ needs it, and that is one of the the most
3759 common uses of piping. The \^procmail^\ local delivery agent also makes
3760 use of the \"From_"\ line. If you do not want it, change the setting of
3761 \message_prefix\ on the \%pipe%\ transport. For example, to remove the
3762 line altogether, use
3764 ==> message_prefix =
3766 If you are not piping to \(/usr/ucb/vacation)\ or \^procmail^\, it is
3767 likely that you do not need a \"From_"\ line, and indeed it may cause
3768 problems if it is present.
3770 One user reported that this line gave trouble when a pipe was used to
3771 send messages to Courier's \^deliverquota^\ program. The line was
3772 retained with the message, and caused problems for MS Exchange 2000 when
3773 retrieving messages with its built-in POP collector. Specifically, it
3774 caused Exchange to not be able to recognise message attachments.
3777 Q0613: I have set \fallback_hosts\ on my \%smtp%\ transport, but after the error
3778 \*sem@chat.ru cannot be resolved at this time*\ Exim isn't using them.
3780 A0613: \fallback_hosts\ works only if an attempt at delivery to the original
3781 host(s) fails. In this case, Exim couldn't even resolve the domain
3782 \(chat.ru)\ to discover what the original hosts were, so it never got as far
3783 as the transport. However, see Q0315 for a possible solution.
3786 Q0614: After the holidays my ISP has always hundreds of e-mails waiting for me.
3787 These are forced down Exim's throat in one go. Exim spawns a lot of
3788 kids, but is there some limit to the number of processes it creates?
3790 A0614: Unless you have changed \smtp_accept_queue_per_connection\ it should
3791 spawn only that many processes per connection (default 10). Your ISP
3792 may be making many connections, of course. That is limited by
3796 Q0615: When a message in the queue got to 12h old, Exim wrote \*retry timeout
3797 exceeded*\ and removed all messages in the queue to this host - even
3798 recent messages. How I can avoid this behaviour? I only want to remove
3799 messages that have exceeded the maximum retry time.
3801 A0615: Exim's retrying is host-based rather than message-based. The philosophy
3802 is that if a host has been down for a very long time, there is no point
3803 in keeping messages hanging around. However, you might like to check
3804 out \delay_after_cutoff\ in the \%smtp%\ transport. It doesn't do what you
3805 want, but it might help.
3808 Q0616: Can Exim add a ::Content-Length:: header to messages it delivers?
3810 A0616: You could include something like
3812 ==> headers_remove = "content-length"
3813 headers_add = "Content-Length: $message_body_size"
3815 to the \%appendfile%\ transport. However, the use of ::Content-Length:: can
3816 cause several problems, and is not recommended unless you really know
3817 what you are doing. There is a discussion of the problems in
3818 \?http://home.netscape.com/eng/mozilla/2.0/relnotes/demo/content-length.html?\.
3821 Q0617: Exim seems to be trying to deliver a message every 10 minutes, though
3822 the retry rules specify longer times after a while, because it is
3823 writing a log entry every time, like this:
3825 ==> 1999-08-26 14:51:19 11IVsE-000MuP-00 == example@example.com T=smtp defer
3826 (-34): some host address lookups failed and retry time not reached for
3827 other hosts or connection limit reached
3829 A0617: It is looking at the message every 10 minutes, but it isn't actually
3830 trying to deliver. It's looking up \(example.com)\ in the DNS and finding
3833 ==> example.com. MX 10 example-com.isp.example.com.
3834 example.com. MX 0 mail.example.com.
3835 mail.example.com. A 202.77.183.45
3836 A lookup for example-com.isp.example.com. yielded NXDOMAIN
3838 The last line means that there is no address (A) record in the DNS for
3839 \(example-com.isp.example.com)\. That accounts for \*some host address
3840 lookups failed*\, but the retry time for \(mail.example.com)\ hasn't been
3841 reached, which accounts for \*retry time not reached for other hosts*\.
3844 Q0618: I am trying to set exim up to have a automatic failover if it sees that
3845 the system that it is sending all mail to is down.
3847 A0618: Add to the \%remote_smtp%\ transport the following:
3849 ==> fallback_hosts = failover.server.name(s)
3851 If there are several names, they must be separated by colons.
3854 Q0619: I can't get Exim to deliver over NFS. I get the error \*fcntl() failed:
3855 No locks available*\, though the lock daemon is running on the NFS server
3856 and other hosts are able to access it.
3858 A0619: Check that you have \(lockd)\ running on the NFS client. This is not
3859 always running by default on some systems (Red Hat is believed to be one
3863 Q0620: Why does Exim bounce messages without even attempting delivery, giving
3864 the error \*retry time not reached for any host after a long failure
3867 A0620: This message means that all hosts to which the message could be sent
3868 have been failing for so long that the end of the retry period
3869 (typically 4 or 5 days) has been reached. In this situation, Exim still
3870 computes a next time to retry, but any messages that arrive in the
3871 meantime are bounced straight away. You can alter this behaviour by
3872 unsetting the \delay_after_cutoff\ option on the smtp transport. Then Exim
3873 will try most messages for those hosts once before giving up.
3876 Q0621: My \(.forward)\ file is \"|/usr/bin/procmail -f-"\ and mail gets delivered,
3877 but there was a bounce to the sender, sending him the output of procmail.
3878 How can I prevent this?
3880 A0621: Exim's default configuration is set up like this:
3886 The \return_output\ option requests that any output that the pipe
3887 produces be returned to the sender. That is the safest default. If you
3888 don't want this, you can either remove the option altogether, or change
3889 it to \return_fail_output\, to return output only if the command fails.
3890 Note that this will affect all pipes that users run, not just your
3891 procmail one. It might be better to arrange for procmail not to produce
3892 any output when it succeeds.
3895 Q0622: Can I write an ordinary file when I run a perl script as a transport
3896 filter for the \%remote_smtp%\ and \%address_pipe%\ transports?
3898 A0622: Yes, provided the file is writeable by the uid under which the transport
3899 runs (the Exim user in the case of the remote transport). However, if two
3900 messages are being delivered at once, their data will get mixed up in
3901 the file unless you implement your own locking scheme. If all you want
3902 to do is to take a copy of the message, another approach that avoids
3903 the locking problem is to use a system filter to set up an ``unseen''
3904 delivery to a file. If you only want the message's headers, you can
3905 set \message_filter_file_transport\ to point to a special \%appendfile%\
3906 transport that has \headers_only\ set.
3909 Q0623: My \(/var/spool/mail)\ has grown drastically. Is there any possibility of
3910 using two directories?
3912 A0623: You can use an expansion string to split mailboxes between two
3913 directories. For example,
3915 ==> file = /var/spool/mail${nhash_2:$local_part}/$local_part
3917 which does a hash on the local part, producing either 0 or 1, thereby
3918 using \(mail0) or \(mail1)\. But remember, the MUAs that read these mailboxes
3919 also have to know where they are.
3922 Q0624: Sendmail has a program called \^smrsh^\ that restricts what binaries
3923 can be run from sendmail aliases. Is there something like this in Exim ?
3925 A0624: Check out the \allow_commands\ option in the \%pipe%\ transport.
3928 Q0625: I wish to have large emails go out one at a time.
3930 A0625: One possibility is to set up a router that defers all large messages,
3931 except in queue runs. Since queue runners deliver just one
3932 message at a time, if you limited the number of simultaneous queue
3933 runners to 1, you would get the effect you wanted. A suitable router
3936 ==> defer_if_large_unless_queue_run:
3938 condition = ${if or{{queue_running}{<{$message_size}{200K}}}{no}{yes}}
3940 data = :defer: too large for immediate delivery
3943 Of course, this would always delay any large message until the next
3944 queue runner, but if you run them fairly regularly, this shouldn't be a
3945 huge problem, and may even be desirable. Note the use of \no_verify\ to
3946 ensure that this router is not used when Exim is verifying addresses.
3949 Q0626: Exim can route local parts independent of their case, but the Cyrus LMTP
3950 daemon requires the correct case. How can I fix this?
3952 A0626: You need to rewrite the local part to the correct case before running
3953 the router that routes to Cyrus. For example, if you require all lower
3954 case, and your router is called \local_user\, put this router in front
3957 ==> lowercase_local:
3959 redirect_router = local_user
3960 domains = +local_domains
3961 data = ${lc:$local_part}@$domain
3963 The setting of \redirect_router\ causes processing of the rewritten
3964 address to start at the next router, instead of the first router. See
3965 also Q0630, and C045 for a more complete Cyrus configuration.
3968 Q0627: Is there a command I can send to Exim to retry all queued messages
3969 regardless of their retry schedule?
3971 A0627: The \-qff-\ option starts a queue runner that forces a delivery attempt
3972 for all messages, including frozen ones. If you use \-qf-\, frozen
3973 messages are skipped.
3976 Q0628: I have the default retry rule, which I thought meant that Exim should
3977 keep trying for four days, but it seems to be bouncing some messages
3980 A0628: See Q0615 and Q0620.
3983 Q0629: I'm having trouble with quotas and Courier, because Exim is not handling
3986 A0629: You will do better to move the quota handling to Courier. Use \^maildrop^\
3987 as your MDA rather than direct Exim delivery. This also has the
3988 advantage that if you give web access to the mail spool (over \^sqwebmail^\)
3989 you can then use the web front end to edit \^maildrop^\ filter files.
3992 Q0630: How can I configure Exim to deliver to a Cyrus message store?
3994 A0630: (1) The reference manual contains an example that uses pipe delivery.
3996 (2) Here is a transport that uses LMTP delivery, assuming that
3997 \$local_part$\ contains the username:
4002 socket = /var/cyrus/socket/lmtp
4004 (3) This is a transport that delivers direct to a non-inbox mailbox:
4013 command = "/usr/cyrus/bin/deliver -a $local_part \
4014 -m <mailbox-name> $local_part"
4016 This delivers to the Cyrus mailbox \"user.$local_part.<mailbox-name>"\.
4017 Using \"user = $local_part"\ and \"-a $local_part"\ makes it work
4018 without needing an explicit `p' ACL set for `anyone' on the mailbox.
4021 Q0631: I would like to choose a retry rule based on on the sender rather than
4022 the recipient address. Is this possible?
4024 A0631: Yes. The address part of a retry rule is matched as a single-item
4025 address list. Such lists are always expanded, so you can use something
4028 ==> "${if eq{$sender_address}{xxx}{*@*}{no@no}}" quota F,1h,10m; ...
4030 If the sender address is ``xxx'', the pattern expands to ``*@*'', which
4031 matches all recipient addresses; if you want to, you can make this a
4032 more restrictive pattern. If the sender address is not ``xxx'', the
4033 pattern expands to ``no@no'', which is assumed to be a recipient address
4034 that can never match, so the retry rule is skipped.
4037 Q0632: What does the error \*User 1 set for local_mbx_delivery transport is on
4038 the never_users list*\ mean?
4040 A0632: You have configured the \%local_mbx_delivery%\ to run as the user whose
4041 id (uid) is 1. However, this user is on the list defined by the
4042 \never_users\ runtime option, or the \\FIXED_NEVER_USERS\\ compile-time
4043 option. These are ``safety catch'' lists; Exim refuses to deliver to any
4044 user that is on them. The most common use of \never_users\ is to avoid
4045 doing any deliveries as \/root/\, but it can contain other uids.
4048 Q0633: Why is \$domain$\ not set in the \%smtp%\ transport?
4050 A0633: The \%smtp%\ transport can handle several recipient addresses at once.
4051 This happens by default if the host lists for the addresses are
4052 identical. A single copy of the message is sent, using multiple \\RCPT\\
4053 commands to transmit multiple envelope recipients. The \$domain$\
4054 variable is set in the \%smtp%\ transport only if all the recipient
4055 addresses have the same domain. You must have a case where several
4056 addresses with different domains resolve to the same set of hosts.
4058 If you want to restrict the transport so that it handles only a single
4059 domain at once (but still possibly with more than one recipient), set
4061 ==> multi_domain = false
4063 If you want to restrict the transport so that it handles only a single
4064 address at once, set
4069 Q0634: How can I stop a local transport from trying to access the user's home
4070 directory, even when the delivery is to a file that is elsewhere?
4072 A0634: See answer (2) for Q0423.
4075 Q0635: The log message \*error ignored*\ appears after some delivery failures.
4078 A0635: This message is written when Exim fails to deliver a bounce message whose
4079 age is greater than \ignore_bounce_errors_after\. It indicates that the
4080 failing bounce message has been discarded.
4082 The same message is written after failed deliveries when a filter file
4083 uses the \noerror\ feature when setting up a delivery, or if a router
4088 Both of these specify that delivery failures are to be discarded.
4094 Q0701: How do I block unwanted messages from outside my host?
4096 A0701: Exim uses Access Control Lists (ACLs) for controlling incoming mail from
4097 other hosts. A whole chapter in the reference manual is devoted to
4098 describing how they work. A wide variety of conditions can be imposed on
4101 The default Exim run time configuration contains an example of an ACL
4102 which blocks all relaying, and messages whose senders cannot be
4103 verified. This example is heavily commented and worth studying.
4106 Q0702: I don't want to block spam entirely; how can I inspect each message
4107 before deciding whether or not to deliver it?
4109 A0702: Wherever possible, inspection and rejection is best done automatically
4110 in an ACL, that is, before the message is accepted. If you want to
4111 verify manually each message that is classified as spam by an automatic
4112 check, you can arrange for a system filter to freeze such messages after
4113 they have been accepted.
4115 If, after inspection, you decide not to deliver the message, it is
4116 safest to discard it, using the \-Mrm-\ option. Use of the \-Mg-\ option
4117 to force a bounce carries the risk of ``collateral spam'' if the sender
4121 Q0703: How can I test that my spam blocks are working?
4123 A0703: The \-bh-\ option allows you to run a testing SMTP session as if from a
4124 given IP address. For example,
4126 ==> exim -bh 192.168.178.39
4128 In addition to the normal SMTP replies, it outputs commentary about
4129 which tests have succeeded or failed. If you are not interested in the
4130 details, but just want to know if a particular sender at a particular IP
4131 address is able to mail to a particular recipient, you can use the
4132 \exim_checkaccess\ utility, which provides a ``packaged'' version of
4133 \-bh-\. You call it like this:
4135 ==> exim_checkaccess 192.168.53.23 recip@my.domain -f sender@some.domain
4137 If you don't give a sender, \"<>"\ is used (that it, it acts like a
4141 Q0704: How can I test that Exim is correctly configured to use the Realtime
4142 Blackhole List (RBL)?
4144 A0704: The \-bh-\ option allows you to run a testing SMTP session as if from a
4145 given address. The \^exim_checkaccess^\ utility provides a more packaged
4146 version of this facility. You need to know a blocked IP address with
4147 which to test. Such a testing address is kindly provided by Russell
4150 ==> linux.crynwr.com [192.203.178.39]
4152 You can also send mail to \(nelson@linux.crynwr.com)\ from the server
4153 whose RBL block you are testing. The robot that receives that email
4154 will attempt to send a piece of test email in reply. If your RBL block
4155 didn't work, you get a message to that effect. Regardless of whether the
4156 RBL block succeeds or not, it emails you the results of the SMTP
4157 conversation from a host that is not on the RBL, so you can see how your
4158 server looks from the view of someone on the RBL.
4161 Q0705: How can I use tcpwrappers in conjunction with Exim?
4163 A0705: Exim's own control facilities can do all that tcpwrappers can do.
4164 However, if you are already using tcpwrappers for other things it might
4165 be convenient to include Exim controls in the same place.
4167 First of all, ensure that Exim is built to call the tcpwrappers library,
4168 by including \\USE_TCPWRAPPERS=yes\\ in \(Local/Makefile)\. You also need to
4169 ensure that the header file \(tcpd.h)\ is available at compile time, and the
4170 \(libwrap.a)\ library is available at link time, typically by including it in
4171 \\EXTRALIBS\\. You may need to copy these two files from the tcpwrappers
4172 build directory to, for example, \(/usr/local/include)\ and \(/usr/local/lib)\,
4173 respectively. Then you could reference them by
4175 ==> CFLAGS=-I/usr/local/include
4176 EXTRALIBS=-L/usr/local/lib -lwrap
4178 in \(Local/Makefile)\. There are two ways to make use of the functionality,
4179 depending on how you have tcpwrappers set up. If you have it set up to
4180 use only one file, you ought to have something like:
4182 ==> /etc/hosts.allow:
4184 ==> exim : <client_list> : <allow_or_deny>
4188 ==> exim : LOCAL 192.168.0. .friendly.domain special.host : ALLOW
4191 This allows connections from local hosts (chiefly //localhost//), from
4192 the subnet 192.168.0.0/24, from all hosts in \(*.friendly.domain)\, and
4193 from a specific host called \(special.host)\. All other connections are
4194 denied. If you have tcpwrappers set up to use two files, use the
4197 ==> /etc/hosts.allow:
4199 ==> exim : <client_list>
4201 ==> /etc/hosts.deny:
4203 ==> exim : <client_list>
4205 Read the \^hosts_access^\ man page for more ways of specifying clients,
4206 including ports, etc., and on logging connections.
4209 Q0706: How can I get POP-auth-before-relay (aka POP-before-SMTP) support in
4212 A0706: Exim 4 supports the ``whoson'' (\?http://whoson.sourceforge.net?\)
4213 facility for doing this. If you set this up, you can do the check in an
4214 Exim ACL by a statement like this:
4216 ==> require condition = \
4217 ${lookup whoson {$sender_host_address}{yes}{no}}
4219 Otherwise you need to arrange for a list of permitted IP addresses to be
4220 maintained in a file or database, and use this in a \hosts\ condition in
4221 an ACL statement. An Exim user has published this recipe:
4223 \#\#\#\#\?http://www.zeiss.cx/memo/computer/linux/email/exim-s-a-p.html?\
4225 Another Exim user submitted the following idea:
4227 Use a script to grab authenticated IP addresses from the log files of
4228 the POP3 and IMAP4 daemons. These are used to create files in the
4229 directory tree \(/var/db/popb4smtp)\. The existence of a file represents a
4230 valid ``popped recently token'' for the IP address used as the filename.
4232 Another script periodically removes stale files from the tree (after two
4233 hours). There's a small race condition here; it's possible for a file
4234 to be deleted just after it has been updated by the script that watches
4235 the logs. For low-volume servers, the odds of hitting this window are
4238 A POPB4SMTP_CLIENT macro in the Exim configure file provides a reusable
4239 ``has this sender popped recently?'' query:
4241 ==> POPB4SMTP_SUBDIR = /var/db/popb4smtp/${substr_-1_1:$sender_host_address}
4242 POPB4SMTP_CLIENT = ${if exists {POPB4SMTP_SUBDIR/$sender_host_address} \
4243 {$sender_host_address} {0} }
4245 Now you can use it just about anywhere, including in your ACLs. Simple
4248 ==> hostlist relay_hosts = 127.0.0.1/32 : ... : POPB4SMTP_CLIENT
4249 host_lookup = !127.0.0.1/32 : ... : !POPB4SMTP_CLIENT
4250 rfc1413_hosts = !127.0.0.1/32 : ... : !POPB4SMTP_CLIENT
4252 The two scripts (and a FreeBSD startup script for them) are available
4255 \#\#\#\#\?http://people.FreeBSD.org/~sheldonh/popb4smtp-nodb.tar.gz?\
4258 Q0707: I have one or two cases where my host correctly rejects messages, but
4259 the remote host is quite persistent, and keeps trying over and over.
4261 A0707: It is an unfortunate fact that a number of SMTP clients, in violation of
4262 the SMTP RFC, do not treat a permanent error code that is given after
4263 the DATA portion of the transaction as a permanent error. Consequently
4264 they keep resending the message, and the worst offenders do so at very
4267 The only way to stop such behaviour is to blacklist the IP address, or
4268 the envelope sender, or both, in such a way that future messages get
4269 rejected at RCPT time instead of at DATA time. You could also complain
4270 to the remote host's administrators.
4273 Q0708: How can I run customized verification checks on incoming addresses?
4275 A0708: There are a number of possibilities:
4277 (1) If you can implement your checks in Perl, you can use Exim's
4278 facility for running an embedded Perl interpreter. For example, if you
4279 want to run special checks on local addresses, you could use ACL
4280 an statement like this:
4282 ==> require domains = my.local.domain
4283 condition = ${perl{verify}{$local_part}}
4285 The result of the Perl function should be ``yes'' or ``no''.
4287 (2) You could also run an external program in a similar way, by a
4290 ==> require domains = my.local.domain
4291 condition = ${run{/my/verifier $local_part}}
4293 This requires the use of another process, so could prove more expensive
4296 (3) If you are prepared to write C code, read the chapter in the manual
4297 entitled \*Adding a local scan function to Exim*\.
4300 Q0709: Does Exim apply RBL checks to error messages, those with an envelope
4303 A0709: This depends on the ACL configuration. You can test for bounce messages
4304 (by looking for an empty sender address) and thereby exclude them from
4305 RBL checking if you want. This ACL statement does that:
4307 ==> deny senders = ! :
4308 dnslist = blackholes.mail-abuse.org
4310 However, some spam does come with an empty sender address, so this may
4314 Q0710: I want to reject certain sender-recipient combinations, with a specific
4315 message for each such combination.
4317 A0710: Set up a file (or database) containing the messages, keyed by the
4318 combination, for example:
4320 ==> sender1@sdomain1=>recipient1@rdomain1: blocked because...
4321 sender2@sdomain2=>recipient2@rdomain2: blocked because...
4323 If you have lots of recipients for the same sender, it might be easier
4324 to generate this file from more convenient data. In your ACL that is run
4325 for each RCPT command, you can then put:
4327 ==> deny message = ${lookup{$sender_address=>$local_part@$domain}\
4328 lsearch{/that/file}}
4329 condition = ${lookup{$sender_address=>$local_part@$domain}\
4330 lsearch{/that/file}}{yes}{no}}
4332 The condition is tested first. If the lookup succeeds, the condition
4333 succeeds so access is denied. The message is then expanded, but the
4334 lookup won't be repeated, because Exim will have cached the previous
4337 This approach blocks only incoming SMTP messages. If you need to do
4338 similar blocks for messages that do not arrive over SMTP, you have to
4339 set up a suitable \%redirect%\ router with a \:fail:\ setting.
4342 Q0711: Will Exim allow me to create a file of regexs and match incoming
4343 external email to the list - and if a match is found file the offending
4344 message into a special location? Also is it possible to make Exim only
4345 filter parts of an incoming email - e.g. ignore large MIME attachments
4346 for example and only process text/plain?
4348 A0711: You can do some of this in a system filter. For example:
4350 ==> if $message_body matches <...some complicated regex...> or
4351 $message_body matches <...some other regex...> or
4352 $header_from: matches <...regex...> or
4355 save /some/special/file
4358 or instead of \"save"\ you could have \"deliver"\ (to some address) or
4359 \"pipe"\ (to some script).
4361 There isn't any mechanism for ignoring attachments, but \$message_body$\
4362 only looks at the first n bytes of the body, where n defaults to 500 but
4365 A more expensive alternative would be to run a Perl subroutine using the
4366 embedded Perl mechanism. If you passed over the message id, the Perl
4367 code could read the message files on the spool and implement any
4368 algorithm it liked for deciding what should be done.
4371 Q0712: I've hacked sendmail to make an ioctl call at the time of the SMTP RCPT
4372 command, to check if a user has exceeded their email quota. If they have
4373 I issue a temporary failure and a message - can I do this with Exim?
4375 A0712: If you can make this happen in Perl you can use the embedded Perl
4376 facility, and use it from a \condition\ condition in an ACL statement.
4377 You can also use the expansion facility to run an external program, but
4378 this uses more resources because it uses another process.
4381 Q0713: I'd like to pass all messages through a virus-scanning system before
4382 delivery. Can Exim do this?
4384 A0713: One way of achieving this is to deliver all messages via a pipe to a
4385 checking program that resubmits them for delivery in some private way
4386 that can be checked (e.g. on a specific SMTP port, or IP address). One
4387 possibility is to use the `received protocol` field that can be set
4388 for locally submitted mail via the \-oMr-\ command line option. This
4389 router sends all messages that are not from the local host and whose
4390 received protocol is not \"scanned-ok"\ to the \%virus_scan%\ transport:
4394 transport = virus_scan
4395 condition = ${if or {{eq {$received_protocol}{scanned-ok}} \
4396 {eq {$sender_host_address}{127.0.0.1}}}\
4399 One problem is that this approach scans the message for each recipient,
4400 not just once per message.
4402 The virus_scan transport should be set up to pipe the message to a
4403 suitable checking program or script which runs as a trusted user. This
4404 can then re-submit the message to Exim, using \-oMr-\ to set the received
4405 protocol to \"scanned-ok"\, and the \-f-\ option to set the correct envelope
4406 sender address. \**Warning:**\ If you forget to make the resubmitting process
4407 run as a trusted user, the received protocol does not get set, and you
4408 are likely to generate a loop.
4411 Q0714: Is there a way to configure Exim to reject mail to a certain local host?
4413 A0714: No, only to certain domains. To reject at SMTP time, you can put a line
4414 like this in your ACL:
4416 ==> deny message = this domain is deliberately rejected
4417 domains = a.certain.domain
4419 To fail addresses in messages that do not arrive over SMTP, you can set
4420 up a router like this:
4422 ==> reject_a_certain_domain:
4424 domains = a.certain.domain
4426 data = :fail: this domain is deliberately rejected
4429 Q0715: How can I get Exim to remove attachments from messages?
4431 A0715: Exim does not contain facilities for modifying messages. You must use
4432 an external program if you want to do this. You can route messages that
4433 have a ::Content-type:: header line via a pipe to a command that does
4434 the job and then re-submits the message to Exim. Alternatively, you
4435 could use a transport filter to do this job.
4438 Q0716: How can I arrange for each user to have a file listing the only sender
4439 addresses from which she will accept mail? I want to do this so my
4440 family members don't get any spam (or other inappropriate mail).
4442 A0716: Let's assume each user has a file called \(.acceptlist)\ in the home
4443 directory. You can put in your ACL a line like this:
4445 ==> require senders = /home/$local_part/.acceptlist
4447 This will reject RCPT commands when the sender is not in the accept
4448 list for the recipient. (Replace \(/home/$local_part)\ with whatever
4449 the correct path to your user's home directories is.)
4451 One problem with this is that it will block bounce messages, which have
4452 empty senders. You can get round this, by changing the line to this:
4454 ==> require senders = : /home/$local_part/.acceptlist
4456 However, this will, of course, let in spam that has a null sender.
4459 Q0717: When using Nessus on a system that runs Exim, a number of security
4460 issues are raised. Nessus complains that Exim answers to EXPN and/or
4461 VRFY; sometimes it even complains that Exim allows relaying.
4463 A0717: Exim supports EXPN and VRFY only if you permit it to do so in the ACLs
4464 defined by \acl_smtp_expn\ and \acl_smtp_vrfy\, respectively. Otherwise,
4467 ==> 550 Administrative prohibition
4468 252 Administrative prohibition
4470 Maybe the use of 252 is the ``problem''. It is recommended that this be
4471 done (by those that discuss these things) because there are stupid
4472 clients that attempt VRFY before sending a message.
4475 Q0718: Could anyone points me to right rules to prevent sending/receiving
4476 messages to/for domains which have one MX to localhost or only have
4482 Q0719: I would like to have a per-user limit for the maximum size of messages
4485 A0719: The simplest way to do this is to put something in a system filter along
4488 ==> if $message_size is above
4489 "${lookup{$sender_address}lsearch{/some/file}{$value}{10M}}"
4491 fail "Message is larger than $sender_address is allowed to send"
4494 In practice, an additional check that the message has arrived from your
4495 local host or local network is probably wise because sender addresses
4499 Q0720: I set \"accept hosts=192.168.122.96/32"\ in order to accept mail for
4500 relaying from my local LAN, but it doesn't work. What's wrong?
4502 A0720: 192.168.122.96/32 is not a network, it is a single host. Exim uses CIDR
4503 notation for specifying networks, where the number after the slash is
4504 the number of bits in the IP address that must match. Your setting says
4505 ``32 bits must match''. If you really mean to specify ``the next 32
4506 IP addresses'', you need 192.168.122.96/27.
4509 Q0721: I have POP-before-SMTP set up on my Exim server, but some clients use
4510 Outlook Express, which sends queued messages before checking the
4511 mailbox, so it doesn't work.
4513 A0721: Implement SMTP authentication.
4516 Q0722: I installed Amavis and it is working, but bounces are simply vanishing.
4518 A0722: Check that you haven't inadvertently set up the transport like this:
4522 command = "/usr/sbin/amavis -f ${sender_address} -d ${pipe_addresses}"
4524 The last line should be:
4526 ==> command = /usr/sbin/amavis -f <$sender_address> -d $pipe_addresses
4528 The important thing is the <> around the sender address; removal of
4529 the unnecessary "" and {} is just tidying. See the amavis FAQ at
4530 \?http://www.amavis.org/amavis-faq.php3?\.
4533 Q0723: I can't get Pine to work with PLAIN authentication; Exim keeps
4534 responding "535 Incorrect authentication data".
4536 A0723: You need to have this setting in your PLAIN authenticator:
4538 ==> server_prompts = :
4540 This is missing in the examples in all but the most recent Exim
4541 documentation, because it was not realized that PLAIN authentication
4542 could be requested by a client without sending the data with the
4543 request. If the data is not sent, an empty prompt is expected.
4546 Q0724: I have used \":fail:"\ in some aliases; when one of these addresses is
4547 refused, I see the message on the log, but the response to the remote
4548 user is ``unknown user'' instead of the message from the alias file.
4549 How can I change this?
4551 A0724: Have you got a \message\ qualifier in the relevant ACL? Exim uses the
4552 message line in the ACL in preference to the message returned by the
4553 router. This is so you can restrict the amount of information that
4554 ``escapes'' from your site via SMTP if you want to. Remove the \message\
4555 line in the ACL entry that has \"verify = recipient"\ and your message
4558 Alternatively, if you are running Exim 4.10 or later, you can use the
4559 \$acl_verify_message$\ variable in your message to include the message
4560 from the router. See also Q0725.
4563 Q0725: I've set up some specific rejection messages for certain recipients, but
4564 when I test them, the SMTP message is always \*550 5.1.1
4565 <user@mydomain.com>... User unknown*\.
4567 A0725: That is not an Exim message (the ``5.1.1'' is a clue; Exim doesn't use
4568 those extended codes). You are probably being defeated by software that
4569 sees the 550 error code, and insists on putting in its own text. There
4570 is stupid software that does this. You can test Exim by using \-bh-\ or
4571 making a telnet call to the SMTP port. That way, there's no other
4572 software intervening.
4575 Q0726: My SMTP authentication can be bypassed by sending an unknown user name
4576 and an empty password. What is wrong with this condition in a PLAIN
4579 ==> server_condition = ${if eq{$2} {${lookup mysql{SELECT password FROM \
4580 accounts WHERE username='${local_part:$1}'}}}{1}{0}}
4582 A0726: Your lookup item returns an empty string when the user does not exist.
4583 You should instead arrange for the lookup to fail:
4585 ==> server_condition = ${if eq{$2} {${lookup mysql{SELECT password FROM \
4586 accounts WHERE username='${local_part:$1}'}{$value}fail}}{1}{0}}
4589 Q0727: When a message has many recipients, how can I stop SpamAssassin from
4590 being called for each of them? I'm running it from a pipe transport.
4592 A0727: In the transport configuration, set \batch_max\ to a value greater than
4596 Q0728: How do I use Exiscan, SA-Exim, SpamAssassin, Clam Antivirus, Sophos
4597 SAVI, or sophie with Exim?
4599 A0728: There's a mini-HOWTO about these available via
4600 \?http://www.timj.co.uk/linux/exim.php?\.
4601 See also sample configuration C047.
4604 Q0729: How can I screen out addresses that are neither valid usernames or
4605 distribution lists on mail being forwarded to an internal Win2K server?
4607 A0729: A user suggested using a router like this to do the recipient
4610 ==> verify_user_router:
4612 domains = win2kdomain.com
4614 ldap;user="cn=ldap-guest,cn=Users,dc=win2kdomain,dc=com"\
4616 ldap:://win2kpdc/dc=win2kdomain,dc=com?mailNickname?\
4617 sub?(&(mailNickname=$local_part)\
4618 (showInAddressBook=*)(sAMAccountName=*))
4621 Set up ldap-guest as a normal domain user on the Win2K PDC.
4623 Also, you need to set \no_verify\ on all the other routers that handle
4627 Q0730: How can I use the same passwords for SMTP authentication as I use for
4628 Courier IMAP access to my server?
4630 A0730: You can access the Courier authdaemon from an Exim authenticator. You
4631 must arrange for the Exim user (often \/exim/\ but sometimes \/mail/\)
4632 to be able to access \(/var/run/courier/authdaemon/socket)\. The
4633 configuration is something of a hack, but it is reported to work. Here
4634 is a LOGIN authenticator:
4639 server_prompts = Username:: : Password::
4640 server_condition = \
4641 ${if eq {${readsocket{/var/run/courier/authdaemon/socket}\
4642 {AUTH 76\n${length_76:exim\nlogin\n$1\n$2\
4643 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
4644 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
4645 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n}}}}{FAIL\n} {no}{yes}}
4648 Here is a PLAIN authenticator:
4654 server_condition = \
4655 ${if eq {${readsocket{/var/run/courier/authdaemon/socket}\
4656 {AUTH 76\n${length_76:exim\nlogin\n$2\n$3\
4657 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
4658 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
4659 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n}}}}{FAIL\n} {no}{yes}}
4663 Q0731: Is there any defence I can use against spam sent through an open proxy?
4665 A0731: The \*ident*\ feature can be used in some cases. See the discussion in
4669 Q0732: I would like to either warn or deny when a host uses an underscore in
4674 ==> helo_allow_chars = _
4676 This tells Exim not to reject the EHLO or HELO command immediately. Once
4677 you have done that, you can test for the underscore in an ACL. For
4678 example, to log a warning for hosts in your LAN, and reject for other
4679 hosts, you could do something like this:
4681 ==> deny message = Underscores are not valid in host names
4682 hosts = ! +lan_hosts
4683 condition = ${if match{$sender_helo_name}{_}{yes}{no}}
4685 ==> warn log_message = Accepted underscore from [$sender_host_address]
4686 condition = ${if match{$sender_helo_name}{_}{yes}{no}}
4689 Q0733: Is there any way to tell Exim not to lookup the IP address against any
4690 DNS black list if the connection is over IPv6?
4692 A0733: Use this condition in your ACL:
4694 ==> condition = ${if match{${mask:$sender_host_address/0}}\
4695 {${mask:::0/0}}{no}{yes}}
4697 From Exim 4.23 onwards, this can be simplified to
4699 ==> condition = ${if isip6{$sender_host_address}{no}{yes}}
4702 Q0734: How do MailScanner and Exiscan compare? What are the pros and cons?
4704 A0734: The big advantage of Exiscan is that it can reject messages at SMTP time
4705 before you have accepted responsibility for them, which means you don't
4706 have to deal with bouncing messages and thereby becoming a collateral
4709 The big advantage of MailScanner is that it gives you much greater
4710 control over the load on your machines. You configure it according to
4711 the maximum processing capacity of your computer and it will not exceed
4712 that; in fact because it deals with messages in batches the cost of
4713 processing a message actually goes down slightly as the load increases,
4714 because the per-batch costs are shared by more messages.
4716 With Exiscan, you have to rely on Exim's load protection mechanisms,
4717 which basically means that you have to stop accepting messages when your
4718 machine gets too loaded. This is bad if the machine happens to be an
4719 SMTP smarthost. You therefore need more overcapacity with Exiscan than
4723 Q0735: How can I block non-FQDNs in HELO/EHLOs?
4725 A0735: Many workstation clients send single-component names; take care that you
4726 do not block legitimate mail. With that proviso, you can do it using
4727 something like this in an ACL:
4729 ==> drop message = HELO doesn't look like a hostname
4730 log_message = Not a hostname
4731 condition = ${if match{$sender_helo_name} \
4732 {\N^[^.].*\.[^.]+$\N}{no}{yes}}
4734 This means: Drop the HELO unless it contains a dot somewhere in the HELO
4735 string, but the string may not begin or end with a dot. Thus, the
4736 imposed minimum length is 3 characters.
4738 The data for HELO/EHLO doesn't have to be a host name; it may
4739 legitimately be an IP address literal instead. The above test succeeds
4740 with an IPv4 address literal, but if you want also to accept IPv6
4741 address literals, you will have to modify the regular expression.
4744 Q0736: Is it possible to tell exim to drop the connection after a server
4745 attempts to send a message to a number of unknown users?
4747 A0736: Yes. Use \$rcpt_fail_count$\ and the \^drop^\ ACL command, as in this
4750 ==> drop message = Too many unknown users
4751 condition = ${if >{$rcpt_fail_count}{15}{yes}{no}}
4754 Q0737: Is there some way to tell Exim not to consider 127.0.0.1 as a valid MX?
4759 Q0738: How can I configure Exim to delay the SMTP connection if more than 10
4760 invalid recipients are received in one message?
4762 A0738: Put something like this in your RCPT ACL:
4764 ==> deny message = Max $rcpt_fail_count failed recipients allowed
4765 condition = ${if >{$rcpt_fail_count}{10} {1}}
4766 ! verify = recipient
4767 delay = ${eval: $rcpt_fail_count * 10}s
4768 log_message = $rcpt_fail_count failed recipient attempts
4770 This example increases the delay for each failed recipient.
4773 Q0739: Does Exim support SPF?
4775 A0739: An Exim ACL can be used. See \?http://spf.pobox.com/downloads.html?\.
4779 8. REWRITING ADDRESSES
4781 Q0801: How can I get Exim to strip the hostname from the sender's address?
4783 A0801: If you set up a rewriting rule in the following form:
4785 ==> *@*.your.domain $1@your.domain
4787 then Exim will rewrite all addresses in the envelope and the headers,
4788 removing anything between \"@"\ and \"your.domain"\. This applies to all
4789 messages that Exim processes. If you want to rewrite sender addresses
4790 only, the the rule should be
4792 ==> *@*.your.domain $1@your.domain Ffrs
4794 This applies the rule only to the envelope sender address and to the
4795 ::From::, ::Reply-to::, and ::Sender:: headers.
4798 Q0802: I have Exim configured to remove the hostname portion of the domain on
4799 outgoing mail, and yet the hostname is present when the mail gets
4802 A0802: Check the DNS record for your domain. If the MX record points to a CNAME
4803 record instead of to an A record, some MTAs (not Exim) are liable to
4804 rewrite addresses, changing your domain name to its ``canonical'' form,
4805 as obtained from the CNAME record.
4808 Q0803: I want to rewrite local addresses in mail that goes to the outside
4809 world, but not for messages that remain within the local intranet.
4811 A0803: You can use the \headers_rewrite\ option on a transport to do this.
4812 The rewriting will then apply to just those copies of a message that
4813 pass through the transport. The \return_path\ option can similarly be
4814 used to rewrite the sender address. There is no way of rewriting
4815 recipient addresses at transport time. However, as these are by
4816 definition remote addresses, you probably don't want to rewrite them.
4818 You have to set up the configuration so that it uses different SMTP
4819 transports for internal and external mail. If you are using a single
4820 router in both cases, you could configure it like this:
4824 transport = ${if match{$domain}{\N\.my\.domain$\N}{int_smtp}{ext_smtp}}
4826 This example uses the \%int_smtp%\ transport for domains ending in
4827 \(.my.domain)\, and \%ext_smtp%\ for everything else. The \%ext_smtp%\ transport
4828 could be something like this:
4832 headers_rewrite = *@*.my.domain \
4833 ${lookup{$1}cdb{/etc/$2/mail.handles.cdb}{$value}fail}
4835 ${if match{$return_path}{\N^([^@]+)@(.*)\.my\.domain$\N}\
4837 ${lookup{$1}cdb{/etc/$2/mail.handles.cdb}{$value}fail}\
4841 This example uses a separate file of local-to-external address
4842 translations for each domain. This is not the only possibility, of
4843 course. The \headers_rewrite\ and \return_path\ options apply the same
4844 rewriting to the header lines and the envelope sender address,
4848 Q0804: I'm using this rewriting rule to change login names into ``friendly''
4849 names, but if mail comes in for an upper case login name, it doesn't
4852 ==> *@my.domain ${lookup{$1}dbm{/usr/lib/exim/longforms}\
4853 {$value}fail}@my.domain bcfrtFT
4855 The longforms database has entries of the form:
4857 ==> ano23: A.N.Other
4859 A0804: Replace \"$1"\ in your rule by \"${lc:$1}"\ to force the local part to lower
4860 case before it is used as a lookup key.
4863 Q0805: Is it possible to completely fail a message if the rewrite rules fail?
4865 A0805: It depends on what you mean by ``fail a message'' and what addresses you
4866 are rewriting. If you are rewriting recipient addresses for your local
4869 ==> *@dom.ain ${lookup{$1}dbm{/wher/ever}{$value}{failaddr}} Ehq
4871 and in your alias file put something like
4873 ==> failaddr: :fail: Rewriting failed
4875 This fails a single recipient - others are processed independently.
4878 Q0806: I'm using \$domain$\ as the key for a lookup in a rewriting rule, but its
4879 contents are not being lowercased. Aren't domains supposed to be handled
4882 A0806: The value of \$domain$\ is the actual domain that appears in the address.
4883 It could of course be lower cased, but I know that would cause some
4884 unhappiness, because some people have mixed-case domain names which look
4885 silly if the case is changed. Thus, one wants to preserve the case in
4888 ==> *@*.TheRap.com something@$domain
4890 because ``therap'' doesn't look like two words. I know it seems trivial,
4891 but it is important to some people - especially if by some unfortunate
4892 accident the lowercased word is something indecent.
4894 You can trivally force lower casing by means of the \"${lc:"\ operator.
4895 Instead of \"$domain"\ write \"${lc:$domain}"\.
4898 Q0807: I want to rewrite local sender addresses depending on the domain of the
4901 A0807: In general, this is not possible, because a message may have more than
4902 one recipient and Exim keeps just a single copy of each message. It may
4903 also deliver one copy of a message with several recipient addresses.
4904 You can do an incomplete job by using a regular expression match in a
4905 rewrite rule to test, for example, the contents of the ::To:: header. This
4906 would work except in cases of multiple recipients.
4912 Q0901: I would like add some custom headers to selected outgoing mail based on
4913 a specific domain and the subject line.
4915 A0901: To the remote_smtp transport, add something like
4917 ==> headers_add = ${if and{\
4918 {eq{$domain}{spec.dom}}\
4919 {matches{$h_subject:}{whatever}}}\
4920 {Content-Type: text/html; charset="us-ascii"} fail }
4922 This example shows a ::Content-Type:: header, but you can have anything you
4923 like, and multiple headers can be inserted by using \"@\n"\ to separate them.
4926 Q0902: Is it possible to have Exim add a header to only certain local parts of
4929 A0902: Only if you arrange for each such local part to receive its own private
4930 copy of the mail. See \max_rcpt\ in the SMTP transport. If you set this
4931 to 1, you could use conditions in an expansion string to add or not add
4935 Q0903: How can I remove some part of the ::Received:: header?
4937 A0903: Set \received_header_text\.
4940 Q0904: How I can insert the PGP header line using Exim filters?
4942 A0904: You can't insert headers in a user filter. A system filter can do so,
4943 but the inserted lines then are included for all recipients.
4946 Q0905: I know I can use a system filter to replace certain headers in messages,
4947 but how can I add text to existing headers? I want to add [SPAM] to
4948 the subject line of messages that appear to be spam.
4950 A0905: You can only do this in a round about way, using filter commands like
4953 ==> headers add "New-Subject: SPAM: $h_subject:"
4954 headers remove subject
4955 neaders add "Subject: $h_new-subject:"
4956 headers remove new-subject
4958 This trick works only in system filters, where the commands are obeyed
4959 in order, and affect the master list of headers that apply to the whole
4960 message. You cannot do this with the \headers_add\ and \headers_remove\
4967 Q1001: I'm running a large mail server. Should I set \split_spool_directory\ to
4968 improve performance?
4970 A1001: Splitting the spool directory has most benefit if there are times when
4971 there are a large number of messages on the queue. If all mail is
4972 delivered very quickly, and the queue is always less than, say, a few
4973 hundred messages, there isn't any need to do this. With larger queues,
4974 there is a definite performance benefit to splitting the spool. It shows
4975 up earlier on some types of filing system, compared with others.
4977 Exim was not designed for handling large queues. If you are in an
4978 enviroment where lots of messages remain on the queue for long periods
4979 of time, consider implementing a back up host to which you pass these
4980 messages, so that the main host's queue remains short. You can use
4981 \fallback_hosts\ to do this, or a router that is conditional on
4985 Q1002: How well does Exim scale?
4987 A1002: Although the author did not specifically set out to write a high-
4988 performance MTA, Exim does seem to be fairly efficient. The biggest
4989 server at the University of Cambridge (a large Sun box) goes over
4990 100,000 deliveries per day on busy days (it has over 20,000 users).
4991 There was a report of a mailing list exploder that sometimes handles
4992 over 100,000 deliveries a day on a big Linux box, the record being
4993 177,000 deliveries (791MB in total). Up to 13,000 deliveries an hour
4996 These are quotes from some Exim users:
4998 "... Canada's largest internet provider, uses Exim on all of our mail
4999 machines, and we're absolutely delighted with it. It brought life back
5000 into one of our machines plagued with backlogs and high load averages.
5001 Here's just an example of how much email our largest mail server
5002 (quad SS1000) is seeing ... " [230,911 deliveries in a day: 4,475MB]
5004 "... Exim has to ... do gethostbyname()s and RBL lookups on all of the
5005 incoming mail servers, and he runs from inetd (TCP Wrappers connected).
5006 All the same, it seems to me that he runs as fast as lightning on our
5007 SCO 5.0.4 box (1 Pentium 166) - far faster than MMDF which I (and many
5008 customers) had before."
5010 "On a PII 400 with 128M of RAM running Linux 2.2.5, I have achieved
5011 36656 messages per hour (outgoing unique messages and recipients). For
5012 about a 5 minute period, I was able to achieve an average of 30 messages
5013 per second (that would be 108000 m/hour)! We are using: (options that
5017 split_spool_directory
5019 remote_max_parallel = 1
5021 We have a cron job hat runs every five minutes that spawns 5 \"exim -q"\ if
5022 there are less that 120 exim processes currently running. We found
5023 that by manually controlling the concurrency of \"exim -q"\ processes
5024 contending for the spool for \%remote_smtp%\ delivery that we gained
5025 considerable performance - 10000 m/hour."
5028 Q1003: We have a large password file. Can Exim use alternative lookups during
5029 delivery to speed things up?
5031 A1003: If you are using FreeBSD, this problem should not arise, because it
5032 automatically uses an indexed password file. In some other operating
5033 systems you can arrange for this to happen too. On Linux, for example,
5034 all you need to do is
5039 and put \"db"\ before \"files"\ in any \(/etc/nsswitch.conf)\ lines you want to
5042 On systems that do not include support for indexed password files, you
5043 can build one yourself, and reference it from the Exim configuration.
5044 For example, for routing to local mailboxes you could use this:
5048 condition = ${lookup{$local_part}cdb{/etc/passwd.cdb}{yes}{no}}
5049 transport = local_delivery
5050 user = ${extract{1}{:}{${lookup{$local_part}cdb{/etc/passwd.cdb}}}
5052 This assumes a cdb version of the password file.
5055 Q1004: I just wondered if it might be helpful to put the hints database on a
5056 RAM disk during regular operation. Did anybody try that yet?
5058 A1004: A user reported thus: ``I have found that this works great under Solaris.
5059 Make a RAM disk partition and keep everything in the \(db)\ directory on
5060 it. However, when I try the same thing on Linux, I don't see the same
5061 boost. I think that Linux's file buffer cache works about the same.
5062 Plus, this leave more room for processes to run.''
5064 There have been other reports that Linux's delayed buffer write provides
5065 better overall performance in general.
5067 Apparently there is support in the Solaris kernel for a delayed writing,
5068 as in Linux, but Sun's server policy is to have it disabled so that you
5069 don't lose so much if the server crashes. There is a program called
5070 \^fastfs^\ to enable and disable this support. You have to download and
5071 compile it yourself; find it by looking for \"fastfs.c"\ in a search
5072 engine. Solaris performance is reported to be much improved, but you
5073 should take care to understand the potential hazards. In particular,
5074 \^fsck^\ may be unable to ``fix'' disks automatically after a crash.
5077 Q1005: A lot of incoming mail is pushing up my system load too much, and there
5078 are many Exim processes. How can I control this?
5080 A1005: Have you set any of the Exim configuration options that limit what it
5081 does under high load? For example, queue_only_load, deliver_queue_load_max?
5082 See the list in the section entitled \*Resource control*\ in the manual.
5084 It sounds like a lot of simultaneous incoming mail pushes your system
5085 into uncontrolled overload. The multiple Exim processes are probably
5086 just multiple incoming messages. You can use the \^exiwhat^\ utility to
5093 Q1101: How do I set up Majordomo to work with Exim?
5095 A1101: Users have found several ways of setting up Exim for use with Majordomo.
5096 One way has been documented at
5097 \?http://www.averillpark.net/exim/majordomo.html?\.
5099 Somewhere in the Majordomo docs or FAQ it mentions using batchmail or
5100 other additional programs to improve the performance of large lists.
5101 They are not needed with Exim, and their use can actually make things
5102 worse. However, it's a good idea to set \remote_max_parallel\ to a value
5103 greater than 1 in the Exim configuration.
5106 Q1102: I have set \$mailer$\ in \(majordomo.cf)\, but it still isn't setting the
5107 sender correctly in the messages it sends.
5109 A1102: Make sure you have got the quoting correct in the \$mailer$\ setting. For
5112 ==> $mailer = "$sendmail_command -oi -oee -f$sender\@lists.mydomain.de";
5114 is not correct. It needs three backslashes, not one, and the $ at the
5115 start of \$sender$\ has to be escaped with a backslash.
5118 Q1103: I'm trying to set up majordomo, but I'm getting a wrong mode error
5119 when I try to send it mail.
5121 A1103: Check the mode of \(/var/lib/majordomo/lists/lists.aliases)\ and compare it
5122 with the setting of the \modemask\ option in the Majordomo aliases
5123 router. This option specifies bits which must not be set for the alias
5124 file, and it defaults to 022.
5127 Q1104: I'm getting return code 9 from \(/home/majordomo/majordomo-1.94.4/wrapper)\
5128 when it is passed a message from Exim.
5130 A1104: A problem like this turned out to be the Perl version that came with
5131 RedHat 5.2. Rebuilding Perl 5.005x solved it.
5134 Q1105: Exim is complaining about an invalid command line when Majordomo tries
5135 to send it a message for delivery.
5137 A1105: Take a look at your \(majordomo.cf)\ file, It should have something that
5140 ==> $sendmail_command = "/usr/lib/sendmail";
5142 and another line like
5144 ==> $mailer = "$sendmail_command -oi -oee -f\$sender";
5146 If you have modified \^resend^\ (one of the majordomo programs) to use
5147 \$sendmail_command$\ instead of \$mailer$\ you will be calling Exim with no
5148 command line arguments.
5154 Q1201: When I run fetchmail, I get the error \*SMTP listener doesn't like
5155 recipient address xxx@localhost*\.
5157 A1201: Make sure that //localhost// is recognized as a domain that is to be
5158 delivered locally. If you are using the default Exim run time
5159 configuration, you'll see a line near the top like this:
5161 ==> domainlist local_domains = @
5165 ==> domainlist local_domains = @ : localhost
5168 Q1202: I'm currently using Exim with fetchmail and I'd like to use the RBL on
5169 Exim, but will it work? Do I need to configure fetchmail any particular
5170 way? As far as Exim knows, all mail is coming from 127.0.0.1. Will it
5171 check the source address against RBL? Or will it check the ::From:: header?
5173 A1202: It will check 127.0.0.1 (not very useful). The point of the RBL is to
5174 keep messages from black-listed hosts out of your machine. If you are
5175 using fetchmail, you have got the messages into your machine before you
5176 approach Exim. That kind of defeats the purpose of the RBL. The right
5177 way to do this would be for the host from which you fetch your mail to
5178 do the RBL checking and insert some kind of warning header for you to
5179 test, as Exim does if you run RBL checks in warning mode.
5185 Q1301: Exim built with Perl support exits with the error message \*./exim: can't
5186 load library 'libperl.so'*\.
5188 A1301: If you are using BSDI, see Q9401.
5191 Q1302: Exim built with Perl support exits with several error messages of the
5192 form \*undefined reference to `PL_stack_sp'*\.
5194 A1302: This has been seen on FreeBSD systems that had two different versions of
5195 Perl installed, the older with an \^a.out^\ library and the newer with an
5196 ELF library. Ensure that the older package is removed.
5200 14. DIAL-UP AND ISDN
5202 Q1401: When I'm not connected to the Internet, how can I arrange for mail to
5203 other hosts on my local network to be delivered, while at the
5204 same time mail to Internet hosts is queued without any delivery
5207 A1401: Use the \queue_domains\ option to control which domains are held
5208 on the queue for later delivery. For example,
5210 ==> queue_domains = ! *.localnet
5212 allows delivery to domains ending in \(.localnet)\, while queueing all the
5216 Q1402: I have a dial-up machine, and I use the \queue_smtp_domains\ option so
5217 that remote mail only goes out when I do a queue run. However, any email
5218 I send with an address \(anything@aol.com)\ is returned within about 15
5219 minutes saying \*retry time exceeded*\, and all addresses are affected.
5221 A1402: You should be using \queue_domains\ rather than \queue_smtp_domains\.
5222 With the latter, Exim is trying to route the addresses, which involves a
5223 DNS lookup. This is presumably timing out, causing a retry time to be
5224 set for the domain, and somehow a valid lookup never happened before the
5225 maximum retry time (default of 4 days) passed. Hence the bounce. The
5226 fact that it is \(aol.com)\ is probably not relevant. You should probably
5227 also be using \-qq-\ to do your queue run rather than \-q-\.
5230 Q1403: How should Exim be configured when it is acting as a temporary storage
5231 system for a domain on a dial-up host?
5233 A1403: Exim isn't really designed for this, but... The lowest-numbered MX
5234 record for the domain should be pointing to the dial-up host. A higher
5235 numbered MX record (lower priority) should point to the Exim server that
5236 is acting as a temporary storage system.
5238 You should set a large retry time for the domain, so that Exim doesn't
5239 keep trying to deliver when the host is offline. When the host comes
5240 online, the waiting messages have to be kicked somehow. This can be done
5241 by calling Exim with the \-R-\ option, or via the SMTP ETRN command.
5243 This works provided the number of messages is low. If you are handling
5244 lots of mail, keeping messages waiting for their host to connect and
5245 those that are having delivery problems to remote hosts all in the same
5246 queue doesn't work so well. It is better in this case to get Exim to
5247 deliver the mail for the dial-in hosts into some local files which then
5248 get transmitted by other software when the host connects. One tool for
5249 doing this can be found at \?http://cr.yp.to/serialmail.html?\.
5251 For further discussion, see section entitled \*Intermittently connected
5252 hosts*\ in the manual, and also the section in the Exim book with the
5256 Q1404: I have \queue_domains\ or \queue_smtp_domains\ set, and use \-qf-\ to
5257 force delivery of waiting mail when I dial in. How can I arrange for any
5258 new messages that arrive while I'm connected to be delivered immediately?
5260 A1404: Instead of \queue_domains\ or \queue_smtp_domains\, use the \queue_only_file\
5261 option. This causes messages to be queued if a particular file exists.
5262 If you put the word ``smtp'' before the file name, the queueing applies
5263 only to domains that are delivered by SMTP, thus not affecting local
5266 ==> queue_only_file = smtp/etc/present/when/not/connected
5268 Then, in the scripts which are run when you connect and disconnect,
5269 arrange to remove the file after connection, and create it just before
5273 Q1405: I have an ISDN connection and would like a way of running the queue
5274 automatically when it is up.
5276 A1405: The following shell commands test for the interface being up and then
5279 ==> ifconfig ppp0 | fgrep UP >/dev/null
5280 if [ $? -eq 0 ] ; then exim -q ; fi
5282 You could put these commands into a script which runs them at regular
5283 intervals. You might want to use \-qq-\ instead of \-q-\.
5285 With Linux, the script \(/etc/ppp/ip-up)\ is run after a ISDN connection
5286 or a more general PPP connection has been established. If you are using
5287 Linux, you could put the call to Exim in that script.
5290 Q1406: When I dial up to collect mail from my ISP, only the first 10 messages
5291 get delivered immediately; the remainder just sit on the queue until a
5292 queue runner process finds them.
5297 Q1407: RFC 1985 specifies that the SMTP command \"ETRN host.domain"\ causes all
5298 mail queued for that host, no matter what domain it's for, to be
5299 delivered. Why doesn't Exim support this?
5301 A1407: Exim does not keep queues of mail for specific destinations. It just
5302 keeps one pool of undelivered messages. What is more, once you start a
5303 delivery of a message, it tries to deliver to all the addresses in the
5304 message, not just the one you may be interested in. (Of course, this
5305 doesn't usually do any harm.)
5307 The only way it could be done within Exim would be, for every message
5308 on the queue, to go through the motions of routing each undelivered
5309 address and see if that resulted in a delivery to the host of interest.
5310 This could be extremely expensive (e.g. 1,000 messages on the queue,
5311 only 1 for the given host).
5313 The bottom line is that Exim just wasn't designed for this kind of
5314 operation, that is, holding messages for intermittently connected hosts.
5315 The queueing arrangements are designed for handling delivery problems
5316 that are not expected to be common.
5318 A better way to do this is to implement the required queues separately.
5319 After all, keeping such mail on an active queue (where Exim will keep
5320 trying to deliver) is silly. If there is a lot of mail for these hosts,
5321 it also masks genuine delivery problems when you inspect the queue.
5323 Large ISPs who provide this kind of functionality do not usually leave
5324 waiting mail on the MTA's queue. Instead, they get it delivered into
5325 per-host directories, one message per file, in one of the special
5326 formats (BSMTP, maildir, or mailstore) and when an ETRN arrives, it
5327 kicks off some completely different program that establishes an SMTP
5328 connection to the host and shovels the waiting mail down it. That seems
5329 to me to be a much neater way of doing this. It means you can easily add
5330 additional functionality such as archiving or throwing away uncollected
5333 One program that has this functionality is \^ssmtp^\, which can be
5334 found in \?ftp://metalab.unc.edu/pub/Linux/system/mail/mta/?\.
5335 Alternatively, sample configuration C037 demonstrates an elegant way of
5336 using Exim itself to deliver the saved messages when the client issues
5340 Q1408: If email has been deferred to a member on a local mailing list
5341 (implemented through forward files), and one of our ETRN clients is on
5342 this mailing list, the \-R-\ won't flush the mailing list message for
5345 A1408: That is because \-R-\ matches only original recipient addresses, not those
5346 produced as a result of expansion, because these are not (by default)
5347 preserved from delivery to delivery. You can get round this by setting
5348 \one_time\ on the forwarding router, but you are not allowed to have
5349 expansions to pipes or files on routers that have \one_time\ set.
5350 Therefore, you will have to have a separate router for mailing lists
5351 (with \one_time\ set) to the one used for normal forward files that might
5352 specify pipe or file deliveries. However, the problem will still be
5353 present for any user who sets up a \(.forward)\ file to redirect to any of
5354 the ETRN domains. See the last 3 paragraphs of Q1407 for a discussion of
5355 an alternative approach.
5358 Q1409: I would like to have a separate queue per domain for hosts which dial
5359 in to collect their mail.
5361 A1409: Exim isn't really designed for this kind of operation. The only way to
5362 do this would be to cause it to send those messages to a differently
5363 configured version of Exim with its own spool area. This could be done
5364 via a pipe or SMTP to a private port. The main Exim, listening on port
5365 25, would then be configured to run an appropriate command to prod one
5366 of the others when it received ETRN, by means of the \smtp_etrn_command\
5369 You could probably manage this with a single Exim binary and a number of
5370 different configuration files, passed to the special versions using the
5371 \-C-\ option. For this application they could all run as \^exim^\, since no
5372 root privilege would be needed.
5374 An alternative approach id to get Exim to deliver mail for such hosts
5375 in batch SMTP format into some directory, and have the ETRN run
5376 something to pass such messages to the dialled-in host. See also Q1403.
5382 Q1501: The MX records for some UUCP domains point to my local host. How do I
5383 get it to pass the messages on to UUCP?
5385 A1501: The simplest way is to create a file containing a list of domains, and
5386 the hosts to which their messages should be sent, like this:
5388 ==> uucp1.domain.example: uucp1.host.example
5389 uucp2.domain.example: uucp2.host.example
5392 Then you can use a router like this:
5396 domains = lsearch;/etc/uucp/domains
5397 transport = uucp_transport
5399 and a transport like this:
5404 command = /usr/local/bin/uux - -r $domain_data!rmail $local_part
5407 The \$domain_data$\ variable retains the value that is looked up when
5408 the \domains\ option in the router is matched.
5411 Q1502: How can I get Exim to handle ``bang path'' addresses?
5413 A1502: In general, you can't (Exim is an Internet mailer and recognizes only
5414 RFC 2822 domain-style addresses) but some restricted kinds of bang path
5415 can be dealt with by appropriate rewriting - but please note the warning
5418 Exim treats a bang path address as an unqualified local part, and so
5419 will qualify it with your domain. A rule such as
5421 ==> \N^([^!]+)!(.+)@your\.domain$\N $2@$1
5423 turns \(a!b@your.domain)\ into \(b@a)\. You can also use a repeating rule to
5424 turn multi-component paths into the ``percent hack'' notation with a rule
5427 ==> \N^([^!]+)!([^@%]+)(.+)$\N $2%$1$3 R
5429 which turns \(a!b@c)\ into \(b%a@c)\ and \(a!b!c@d)\ first into \(b!c%a@d)\ and then,
5430 because of the R flag, into \(c%b%a@d)\. The R flag causes repetition up to
5433 \**Warning:**\ If you install a general rewriting rule like the above, you are
5434 opening yourself up to the possibility of unwanted relaying. A host that
5435 is not permitted to relay through your system could send a message with
5436 an SMTP command line such as
5438 ==> RCPT TO:<victim-host!victim-user@your.domain>
5440 and this would be accepted because it is addressed to your domain.
5441 However, the rewriting then converts the address, and the message does
5442 in fact get relayed. One way round this, if all your bang path messages
5443 are passed to Exim via SMTP, is to use the \"S"\ rewriting flag. This
5444 applies a rewriting rule to incoming SMTP addresses as soon as they are
5445 received, before checking for qualification, relaying, etc. So a rule
5448 ==> \N^([^!]+)!(.+)$\N $2@$1 S
5450 rewrites simple two-component bang paths before the result is checked
5451 for relaying. However, this does not rewrite addresses in the headers of
5455 Q1503: We see something strange on our system in regards to mail coming in via
5456 rmail from a UUCP link. The sender is being set to mailmaster instead of
5457 the real sender, and a ::Sender:: header is being added to the message.
5459 A1503: If \(mailmaster)\ is the user that is running rmail, you need to include
5460 that user in the \trusted_users\ configuration option. Only trusted users
5461 are permitted to specify senders when mail is passed to Exim via the
5466 16. MODIFYING MESSAGE BODIES
5468 Q1601: How can I add a disclaimer or an advertisement to a message?
5470 A1601: There are a number of technical and potential legal problems that arise
5471 in connection with message modification. Some of them are listed below.
5472 Some comment on the legal position of email disclaimers in English law
5473 can be found at \?http://www.weblaw.co.uk/artemail.htm?\.
5475 See also \?http://www.goldmark.org/jeff/stupid-disclaimers/?\. There is
5476 some discussion about the problems of actually adding disclaimers in
5477 \?http://www.goldmark.org/jeff/stupid-disclaimers/apply.html?\.
5479 In many cases, email disclaimers will make your company look ridiculous,
5480 at the very least. At worst, they may interfere with the normal
5483 If, despite these considerations, you still want to modify messages, you
5484 can do so using Exim, but not directly in Exim itself. It is not the job
5485 of an MTA to modify messages, something that requires understanding of
5486 their content and format.
5488 Exim provides a hook called a ``transport filter'' that lets you pass
5489 any outgoing message through a program or script of your choice. It
5490 is the job of this script to make any changes to the message that you
5491 require. By this means, you have full control over what changes are
5492 made, and Exim does not need to know anything about message bodies.
5493 However, using a transport filter requires additional resources, and may
5494 slow down mail delivery.
5496 You can use Exim's routers to arrange for those messages that you want
5497 to modify to be delivered via a transport filter. For example, suppose
5498 you want to do this for messages from addresses in your domain that are
5499 being delivered to a remote host. First you need to set up a special
5500 \%smtp%\ transport that uses a filter, like this:
5502 ==> remote_smtp_filter:
5504 transport_filter = /your/filter/command
5506 Then you need to modify the \%dnslookup%\ router to use this transport
5507 when the conditions are right:
5511 domains = ! +local_domains
5512 transport = ${if eq {$sender_address_domain}{your.domain}\
5513 {remote_smtp_filter}{remote_smtp}}
5514 ignore_target_hosts = 127.0.0.0/8
5517 This is the standard \%dnslookup%\ router, but with a modified setting of
5518 the \transport\ option. When the sender address is in your domain, it
5519 routes to the special transport instead of the standard one.
5521 The entire message is passed to your filter command on its standard
5522 input. It must write the modified version to the standard output, taking
5523 care not to break the RFC 2822 syntax. The command is run as the Exim
5526 There are a number of potential problems in doing this kind of
5527 modification in an MTA. Many people believe that to attempt is it wrong,
5530 1. It breaks digital signatures, which are becoming legally binding
5531 in some countries. It may well also break encryption.
5533 2. It is likely to break MIME encoding, that is, it is likely to wreck
5534 attachments, unless great care is taken. And what about the case of a
5535 message containing only binary MIME parts?
5537 3. It is illegal under German and Dutch law to change the body of
5538 a mail message in transit. It might potentially be illegal in
5539 the UK under European law. This consideration applies to ISPs and
5540 other ``common carriers''. It would presumably not apply in a corporate
5541 environment where modification was done only to messages originating
5542 from the employees, before they left the company's network. It might
5543 also not apply if the senders have explicitly given their consent
5544 (e.g. agreed to have advertisements added to their incoming mail).
5546 4. Since the delivered message body was produced by the MTA (not the
5547 originator, because it was modified), the MTA operator could
5548 potentially be sued for any content. This again applies to `common
5549 carrier' MTAs. It's interesting that adding a disclaimer of liability
5550 could be making you liable for the message, but this case seems
5551 more likely to involve adding advertisements than disclaimers. After
5552 all, no postal service in the world opens all the mail it carries to
5555 5. Some mail clients (old versions of MS outlook) crash if the message
5556 body of an incoming MIME message has been tampered with.
5558 There are also potential problems that could arise if a scheme to add
5559 disclaimers goes wrong for some messages:
5561 1. False negatives: `Ah, this guy usually says he does not represent
5562 their views, but in this message he doesn't have the disclaimer'.
5564 2. False positives: `This official announcement does not represent our
5567 An alternative approach to the disclaimer problem would be to insist
5568 that all relevant messages have the disclaimer appended by the MUA. The
5569 MTA should refuse to accept any that do not. Again, however, the MTA
5570 must understand the format of messages in order to do this. Simply
5571 checking for appropriate wording at the end of the body is not good
5572 enough. It would probably be necessary to run a Perl script from within
5573 an Exim system filter, or write a \^^local_scan()^^\ function in order
5574 to adopt this approach.
5576 Finally, it's a trivial matter to add customized headers of the sort:
5578 ==> X-Disclaimer: This is a standard disclaimer that says that the views
5579 X-Disclaimer: contained within this message are somebody else's.
5581 which is a much easier alternative to modifying message bodies.
5584 Q1602: How can I remove attachments from messages?
5586 A1602: The answer to this is essentially the same as for Q1601.
5590 17. ENCRYPTION (TLS/SSL)
5592 Q1701: I am trying to set up an Exim server that uses a self-signed certificate
5593 to enable my clients to use TLS. However, clients other than Exim
5594 refuse to accept this certificate. What's wrong?
5596 A1701: It seems that some clients require that the certificate presented by
5597 the server be a user (also called ``leaf'' or ``site'') certificate, and not
5598 a self-signed certificate. In this situation, the self-signed
5599 certificate must be installed on the client as a trusted root
5600 \*certification authority*\ (CA), and the certificate used by the server
5601 must be a user certificate signed with that self-signed certificate.
5603 For information on creating self-signed CA certificates and using them
5604 to sign user certificates, see the \*General implementation overview*\
5605 chapter of the Open-source PKI book, available online at
5606 \?http://ospkibook.sourceforge.net/?\. Here is a quick overview. First,
5609 \?http://www.FreeBSD.org/cgi/mid.cgi?id=3C3F3A93.C1ECF9B0%40mindspring.com?\
5611 Then, follow the instructions found on these two (consecutive) pages:
5613 \?http://ospkibook.sourceforge.net/docs/OSPKI-2.4.6/OSPKI/initialisation.htm?\
5614 \?http://ospkibook.sourceforge.net/docs/OSPKI-2.4.6/OSPKI/keygensign.htm?\
5616 Two points on the PKI Book literature:
5618 (1) It's assumed that it's okay to use a passphrase-protected key to
5619 encrypt the user/site/leaf certificate. If this isn't acceptable,
5620 you seem to be able to strip out the passphrase as follows:
5622 ==> openssl rsa -in user.key -our user.key.new
5625 This should be done immediately after \(user.key)\ is created.
5627 (2) The \*sign.sh*\ script is available in the \*mod_ssl*\ distribution,
5628 available at \?http://www.modssl.org/source/?\.
5630 Having followed the instructions, you end up with the following files:
5634 This file should be installed into the client software as a trusted
5635 root certification authority. In Windows XP, this can be done as follows:
5637 \#\#Call the file \(ca_cert.cer)\
5639 \#\#Double-click on the file
5641 \#\#"Install Certificate";
5645 \#\#"Place all certificates in the following store"
5649 \#\#"Trusted Root Certification Authorities"
5661 (b) \(user.crt)\ and \(user.key)\
5663 These files should be installed into the server software. In Exim, this
5664 can be done by adding these lines to the configuration file:
5666 ==> tls_certificate = /usr/local/etc/exim/tls_cert
5667 tls_privatekey = /usr/local/etc/exim/tls_key
5669 Then install \(user.crt)\ and \(user.key)\ under the names \(tls_cert)\
5670 and \(tls_key)\ in the appropriate directory.
5673 Q1702: How can I arrange for Exim to advertise support for SMTP authentication
5674 only when the session is encrypted?
5676 A1702: Use this setting:
5678 ==> auth_advertise_hosts = ${if eq{$tls_cipher}{}{}{*}}
5681 Q1703: I have some legacy clients that don't use STARTTLS, but which expect to
5682 negotiate a TLS session automatically on connection to the ssmtp port
5683 (465). Can Exim handle this?
5685 A1703: The \-tls-on-connect-\ option is available to handle this. You need to
5686 run two instances of an Exim listener, listening on different ports, one
5687 of which is started with \-tls-on-connect-\. You can either use two
5688 daemons, or a single daemon, with the other listenever using \^inetd^\.
5689 For example, here are commands to start two daemons:
5692 exim -bd -oX '[0.0.0.0]::465' -tls-on-connect
5694 The first is a ``normal'' daemon; the second listens on port 465 and
5695 expects to negotiate a TLS session at the start of each connection.
5698 Q1704: When my Outlook Express 6.0 client sends a STARTTLS command to begin a
5699 TLS session, Exim doesn't seem to receive it.
5704 Q1705: I have listed some hosts in \tls_try_verify_hosts\, but when they
5705 connect, no data appears in \$tls_peerdn$\.
5707 A1705: This means that the clients have not sent certificates when asked by
5708 the server to do so. If the clients are running Exim, check that
5709 \tls_certificate\ is correctly set in their \%smtp%\ transports. Note
5710 that this value is not automatically inherited from the global
5711 \tls_certificate\ option.
5714 Q1706: I have listed some hosts in \tls_verify_hosts\ and provided them with
5715 certificates, but their connections are always rejected.
5717 A1706: Make sure that the server file containing the expected certificates
5718 (defined by \tls_verify_certificates\) is readable by the Exim user.
5719 See also the answer to Q1705.
5722 Q1707: I am trying to use TLS with Evolution as a client, and keep seeing this
5723 error: \*SMTP protocol violation: synchronization error (next input
5724 sent too soon): rejected "\200F^A^C".*\ What does it mean?
5726 A1707: See Q0086 for a general explanation of the error. In this case, it
5727 probably means that Evolution is trying to negotiate a TLS session
5728 immediately it connects, without first using the STARTTLS command. This
5729 was an older way of starting up TLS, before STARTTLS was defined. You
5730 will have to run a separate instance of Exim using the
5731 \-tls-on-connect-\ command line option to cater for this usage, and
5732 listening on a different port. For example:
5734 ==> exim -bd -oX 465 -tls-on-connect
5736 465 is the ``smtps'' port which is an unofficial standard for this kind
5740 Q1708: I trying to use TLS with Outlook as a client on a box that is running
5741 Norton Antivirus, but all my email is being rejected with \*Unsupported
5742 command*\ errors. Why?
5744 A1708: Norton Antivirus does not support TLS or AUTH. It puts a broken SMTP
5745 proxy between you and the Exim server. You need to turn off outbound
5752 Q2000: Are there any Y2K issues with Exim?
5754 A2000: The author of Exim believes that it is Y2K-compliant, as long as the
5755 underlying operating system and C library are. Exim does not parse dates
5756 or times at all. Internally, it makes some use of binary timestamps in
5757 Unix format (number of seconds since 1-Jan-1970) and uses C library
5758 services to convert these to printing forms (e.g. for logging). The
5759 printing forms all use 4-digit years. Some people have tried various
5760 tests. No problems have been reported, but details of what tests have
5761 been done are not available.
5763 Well, it's now November 2001, and no Y2K problems have been reported, so
5764 it looks like I was right. This entry is retained as historical
5771 Q5001: How can I arrange to allow a limited set of users to perform a limited
5772 set of Exim administration functions? I don't want to put them all in
5775 A5001: See \?http://www.chiark.greenend.org.uk/~ian/userv/?\. Using \^userv^\ you can
5776 arrange (for example) for certain users to be able to invoke \^mailq^\ or
5777 \^runq^\ or other preset commands as \^exim^\ (or any other user, as configured)
5778 with only \^userv^\ configuration. If you want to check the particular Exim
5779 options available you can easily do it with shell or Perl scripts and
5780 \^userv^\ configuration, and provided you know how to do argument
5781 ``unparsing'' properly in shell or Perl it will be secure.
5784 Q5002: I want to ``tail'' the Exim log, but I have a number of other logs I also
5785 want to ``tail'', and the number of tailing windows is getting to be a
5788 A5002: Look for a program called \^xtail^\ (despite its name, it's not an
5789 X-windows application). It allows you to do multiple tails, even of
5792 Alternately, get the GNU version of \^tail^\, from the GNU textutils
5793 package (\?ftp://ftp.gnu.org/gnu/textutils/?\). GNU tail lets you run
5794 \"tail -f\" on multiple files at the same time, although it doesn't work
5795 on entire directories like \^xtail^\ can. If you are running Linux, you
5796 probably already have a version of GNU \^tail^\ that can follow multiple
5800 Q5003: How can I persuade Exim to accept ETRN commands without the leading
5803 A5003: Set the option
5805 ==> smtp_etrn_command = /usr/lib/sendmail -R $domain
5807 This causes Exim to run that command, with \$domain$\ replaced by the
5808 argument of ETRN. The default action of Exim is to require the # sign
5809 in order to be RFC-compliant, and to run the equivalent of
5811 ==> smtp_etrn_command = /usr/lib/sendmail -R ${substr_1:$domain}
5813 which uses the argument without the leading # as the value for the \-R-\
5814 option. You aren't restricted to running Exim with the \-R-\ option, of
5815 course. You can specify any command you like, with any number of
5816 arguments. In particular, you can pass over the IP address of the caller
5817 via \$sender_host_address$\. However, if you make use of expansion strings
5818 in the arguments, each one must be entirely contained in a single
5819 argument. For example, if you want to remove the first character of the
5820 ETRN argument when it is @ or #, you could use
5822 ==> smtp_etrn_command = "/usr/lib/sendmail -R \
5823 \"${if match {$domain}{^[@#]}{${substr_1:$domain}}{$domain}}\""
5825 The internal quotes are necessary because of the white space inside the
5829 Q5004: I've recently noticed that emails I send with a ::Bcc:: line are being
5830 delivered to their final destination with the ::Bcc:: line still present.
5832 A5004: Exim removes ::Bcc:: lines only if you call it with the \-t-\ option (i.e.
5833 when it is acting partly as an MUA). It does not remove ::Bcc:: lines that
5834 are present in incoming SMTP mail or command-line mail that does not
5835 use \-t-\. Indeed, it should not remove them, because only the
5836 initiating software (i.e. the MUA) can tell what to do with ::Bcc::
5837 lines; any MTA software has to leave them alone. This is what RFC 2822
5838 has to say about ::Bcc::
5840 \*The ::Bcc:: field (where the ``Bcc'' means ``Blind Carbon Copy'') contains
5841 addresses of recipients of the message whose addresses are not to be
5842 revealed to other recipients of the message. There are three ways in
5843 which the ::Bcc:: field is used. In the first case, when a message
5844 containing a ::Bcc:: field is prepared to be sent, the ::Bcc:: line is
5845 removed even though all of the recipients (including those specified
5846 in the ::Bcc:: field) are sent a copy of the message. In the second
5847 case, recipients specified in the ::To:: and ::Cc:: lines each are sent
5848 a copy of the message with the ::Bcc:: line removed as above, but the
5849 recipients on the ::Bcc:: line get a separate copy of the message
5850 containing a ::Bcc:: line. (When there are multiple recipient
5851 addresses in the ::Bcc:: field, some implementations actually send a
5852 separate copy of the message to each recipient with a ::Bcc::
5853 containing only the address of that particular recipient.) Finally,
5854 since a ::Bcc:: field may contain no addresses, a ::Bcc:: field can be
5855 sent without any addresses indicating to the recipients that blind
5856 copies were sent to someone. Which method to use with ::Bcc:: fields
5857 is implementation dependent, but refer to the ``Security
5858 Considerations'' section of this document for a discussion of each.*\
5861 Q5005: I used \^gv^\ 3.5.8 (\^ghostview^\) to try printing \(spec.ps)\. After every
5862 printed page, the printer ejects a blank sheet. Is this something to do
5863 with using ``letter'' rather than A4 paper?
5865 A5005: This seems to be an effect of using \^ghostview^\. Although the PostScript
5866 is generated for A4 pages, the size of the page images is such that they
5867 should fit on a letter page (they are shorter than would normally be
5868 used on A4 paper). If the PostScript file is sent directly to a
5869 PostScript printer, there is no problem. An alternative is to get hold
5870 of the \^psutils^\ toolset, which is available from
5871 \?ftp://ftp.dcs.ed.ac.uk/pub/psutils/psutils.tar.gz?\.
5872 It contains utilities for extracting pages (which can be useful for
5873 double-sided printing) and for resizing pages. If you resize from A4 to
5874 letter the text shrinks a bit, but should then be printable via
5878 Q5006: Why aren't there any man pages for Exim? I don't always carry my printed
5881 A5006: A single man page which lists the command line options is provided in
5882 file \(doc/exim.8)\ in the Exim distribution. Several other forms of
5883 online documentation are available. As well as plain ASCII text, the
5884 there are two forms - Texinfo and HTML - which have a certain amount of
5885 built-in indexing for ease of finding your way around. There are no man
5886 pages apart from the command line one because the author of Exim hasn't
5887 the time (or desire :-) to maintain yet another documentation format.
5888 Besides, it is hard to know how to split the Exim manual up.
5891 Q5007: When I send a message using the \-t-\ command line option, Exim sends only
5892 to the addresses within the message, not to those on the command line.
5894 A5007: There seems to be some confusion in the Sendmail community about the
5895 interpretation of recipient addresses on the command line if the \-t-\
5896 option is used. Some versions do one thing, and some another. Here is an
5897 except from one version of the Sendmail documentation for \-t-\:
5899 \*Read message for recipients. ::To::, ::Cc::, and ::Bcc:: lines will
5900 be scanned for recipient addresses. The ::Bcc:: line will be
5901 deleted before transmission. Any addresses in the argument
5902 list will be suppressed, that is, they will not receive
5903 copies even if listed in the message header.*\
5905 By default Exim follows this specification, and interprets addresses on
5906 the command line as addresses not to send to. You can set
5908 ==> extract_addresses_remove_arguments = false
5910 to change this behaviour so that command line addresses are added to the
5911 addresses that are taken from the header lines.
5914 Q5008: If I set up a domain list to contain //*customer.com//, it matches
5915 //customer.com// and //abc.customer.com// as required, but it also matches
5916 //noncustomer.com//, which is wrong. How can I get round this?
5918 A5008: You have to specify two entries in the list:
5920 ==> customer.com : *.customer.com
5922 because * in a domain list matches any characters, including \"."\ and
5923 including a null sequence.
5926 Q5009: I want to match all domains of the form //*.oyoy.org// but want a few
5927 exceptions. For instance I don't want //foo.oyoy.org// or //bar.oyoy.org// to be
5928 included. What is the best way to do this?
5930 A5009: Use negative items in the domain list, like this:
5932 ==> domainlist local_domains = !foo.oyoy.org : !bar.oyoy.org : *.oyoy.org
5934 If there are many exceptions, you can use a lookup instead of listing
5935 them all inline. If there are a number of exceptions that match a
5936 particular pattern, you could use a regular expression.
5939 Q5010: I can't seem to find a pre-built version of Exim anywhere. The machine
5940 is a Sparc 5 running Solaris 2.6.
5942 A5010: The primary distribution is source-only. However, some people have built
5943 and distributed RPMs and debs for Linux systems, and ports for FreeBSD.
5944 I haven't heard of anyone doing this for Solaris. The main problem with
5945 binary distributions is that there are a number of build-time options,
5946 requiring the answers to questions like:
5948 . Which DBM library do you have? (On Solaris probably ndbm, but no easy
5949 default on some other systems.)
5951 . Which uid/gid do you want to use for Exim?
5953 . Where do you want the configuration file to be? (Many different
5954 answers, even on the same OS, depending on local policy.)
5956 . Ditto for the binaries.
5958 . Which optional bits of Exim do you want to include?
5961 Q5011: Is there a version of Exim available that runs under Windows?
5963 A5011: A long time ago somebody took a copy of the Exim source with the aim of
5964 trying to port it to Windows NT. However, I never heard anything more.
5965 However, current versions of Exim can be made to run under Cygwin.
5968 Q5012: Does Exim support Delivery Status Notification (DSN), Message Status
5969 Notification (MSN), or any other form of delivery acknowledgement?
5974 Q5013: What does ``Exim'' stand for?
5976 A5013: Originally, it was ``EXperimental Internet Mailer'', which was the best I
5977 could come up with when I was starting out. At that point it was
5978 experimental - I wanted to see if the ideas I had for extending Smail's
5979 approach actually worked. Then somebody discovered about it and wanted
5980 to start using it, and told other people about it...
5983 Q5014: Although I haven't set \check_spool_space\, Exim is still checking the
5984 amount of space on the spool for incoming SMTP messages that use the
5985 SIZE option. Can I suppress this?
5987 A5014: The RFC for the SIZE option says:
5989 \*If the server currently lacks sufficient resources to accept a
5990 message of the indicated size, but may be able to accept the
5991 message at a later time, it responds with code ``452
5992 insufficient system storage''.*\
5994 and that is what Exim is trying to implement. This is entirely
5995 independent from \check_spool_space\, which says \*don't accept any mail
5996 if there is less than so much space in the spool partition*\, though the
5997 code is optimised to do both checks at the same time if required.
5998 However, you can suppress the SIZE check if you want to, by unsetting
5999 \smtp_check_spool_space\.
6002 Q5015: I just noticed log entries that start off \"<= <>"\. Am I correct in
6003 assuming that the \"<>"\ indicates that the envelope did not contain any
6006 A5015: Yes. This indicates a delivery failure report (aka a ``bounce message''),
6007 as specified in RFC 2821. The reason for using empty sender addresses is
6008 to identify bounce messages so that they themselves do not cause further
6009 bounces. Empty senders are also used for other kinds of report which
6010 should not themselves cause the generation of bounce messages. For
6011 example, Exim uses them when sending out warnings about delivery delays.
6014 Q5016: I've received a message which does not have my address in the ::To::
6015 line. It is a spam message with the same address in both the ::From:: and
6016 the ::To:: headers. How can this happen, and why doesn't Exim reject it?
6018 A5016: There is an important distinction between the ``envelope'' from and to and
6019 the ``header'' from and to. The former are sometimes called the ``sender''
6020 and ``recipient''. An email message needs an ``envelope'' for the same
6021 reason that paper mail does - the envelope tells the delivery mechanism
6022 what to do with this copy of the message, whereas the ::To:: header lists
6023 all the recipients, including those who have been sent different copies
6024 of the message because their mailbox is on some other host.
6026 An MTA such as Exim works entirely with the ``envelope'' addresses, not
6027 with those in the header lines. Don't try to block mail where envelope
6028 from and the header from differ. There are common legitimate cases where
6029 this happens, for example, messages forwarded from mailing lists and
6030 delivery failure reports.
6033 Q5017: Can (or will) Exim ever handle a message delivery purely in memory,
6034 that is, it is handled without it ever hitting the disk?
6036 A5017: It doesn't, and never will. Accepting and delivering a message are two
6037 entirely separate, independent processes, which communicate only by
6038 writing/reading the message on the disk.
6041 Q5018: If I am using dbm files for data that Exim reads, can I rebuild them
6042 on the fly, or do I need to restart Exim every time I make a change?
6044 A5018: Exim re-reads the file every time it consults it, so if you are using a
6045 cdb or a DBM library that uses just a single file (i.e. not ndbm),
6046 you can just build the new file with a temporary file name, and use
6047 \^mv^\ to rename it into the correct place on the fly. If there are two
6048 files to rename, there is a window of time during which the DBM database
6049 is inconsistent. On lightly loaded systems this may not matter.
6052 Q5019: I need an option that is the opposite of \-bpa-\, that is, a listing of
6053 those addresses generated from a top-level address that have not yet
6056 A5019: Exim does not keep this information. It saves only the top-level
6057 addresses and the list of addresses that are finished with. At each
6058 delivery attempt, generated addresses are recomputed from scratch. This
6059 makes it possible to correct errors in redirection data that is
6060 causing delivery delays. However, there is an option you can set on a
6061 \redirect\ router that changes things. It is called \one_time\, and if
6062 it is set, the list of generated addresses gets added to the top-level
6063 list at the first delivery attempt, and is never regenerated. Because
6064 top-level address lists must be real email addresses, this option cannot
6065 be used if any of the generated addresses are pipes, files, or
6069 Q5020: How can I make Exim receive incoming mail, queue it, but not attempt to
6070 deliver it? I want to be in this state while moving some mailboxes.
6072 A5020: Set \queue_only\ in the Exim configuration. Then kill your daemon,
6073 and restart it without the \-q-\ option (i.e. with just the \-bd-\ option),
6074 so that it does not spawn any queue runners. This stops all deliveries,
6075 remote as well as local.
6078 Q5021: What does Exim use for POP and IMAP as a default? Do I have to install
6081 A5021: Yes. Exim provides MTA functionality. That is, it delivers mail. POP and
6082 IMAP are two of several ways of reading previously-delivered mail. Exim
6083 does not provide that functionality. You need to install POP and/or IMAP
6084 daemons; there are several to choose from. There is a mailing list at
6085 //pop-imap@exim.org// for the discussion of POP/IMAP issues.
6088 Q5022: Is there an easy way of removing all queued messages at once in a safe
6091 A5022: Try this command:
6093 ==> exim -bp | awk '/^ *[0-9]+[mhd]/{print "exim -Mrm " $3}' | sh
6096 Q5023: Why does Exim do \*ident*\ callbacks by default? Isn't this just a waste
6097 of resources? I've been told this is an ancient way of authentication.
6100 A5023: This is a common misunderstanding, at least partially resulting from the
6101 incorrect naming of the protocol when it was first published.
6102 The service on port 113 is an identification service, which allows a
6103 target host to record information identifying the user responsible for
6104 making a connection to it. The information may not be intelligible to
6105 the recording host - it could, for example, be encrypted so that only
6106 someone on the calling host can make sense of it. It is useful for
6107 providing additional information in an audit trail.
6109 At least one site has found \^ident^\ effective against two rather
6110 prevalent kinds of open proxy (whether already blacklisted at the RBLs
6111 or not). An ACL statement is used to reject mail from servers that
6112 return \^ident^\ strings of \"squid"\ and \"CacheFlow Server"\.
6113 Snippets such as this in the RCPT ACL do the trick:
6115 ==> deny condition = ${if eq{$sender_ident}{CacheFlow Server}{1}{0}}
6116 message = Rejected - appears to be an unsecured proxy: $sender_ident
6118 The likelihood that a genuine mail process would return those specific
6119 ident strings is vanishingly small.
6121 The \^ident^\ data should not be used for authentication in any form
6122 except on a closed secure network between cooperating hosts (probably
6123 not even then). The information from the source host is only as reliable
6124 as the host itself. If it's not under your control then you have to
6125 treat the information as opaque data that can be used only by the
6126 sysadmin of the source system to trace back connection data. Some
6127 \^ident^\ implementations send out opaque cookies or DES encrypted
6128 information. \^Ident^\ is hugely useful at times - especially for
6129 checking back on connections from multiuser machines (as opposed to
6130 one-person desktop boxes).
6132 You can stop Exim making ident calls by adding
6134 ==> rfc1413_query_timeout = 0s
6136 to its configuration, but it is better to leave it active (reducing the
6137 timeout to 10s or less if it is causing problems) - it costs very
6138 little, and in cases of mail forgery from a multiuser system can track
6139 the sinner concerned very quickly.
6142 Q5024: I often have the problem that a message gets stuck in the mail queue and
6143 I want it to be bounced to a certain address.
6145 A5024: You can do this using a combination of four command line options, like
6148 ==> exim -Mf 14Fdlq-0003kM-00
6149 exim -Mmad 14Fdlq-0003kM-00
6150 exim -Mar 14Fdlq-0003kM-00 new@ddress
6151 exim -M 14Fdlq-0003kM-00
6153 The first command freezes the message so that a queue runner won't start
6154 to deliver it while you are changing things. The second command marks
6155 all existing recipients as delivered. The third command adds a new
6156 recipient, and the fourth command forces a delivery of the message,
6157 which will cause it to be delivered to the new address, and then
6161 Q5025: What precautions should I take when editing Exim's run time
6164 A5025: Edit the file and save the result in a new file. Test the syntax of
6165 the new file by running a command like this:
6167 ==> exim -bV -C exim.conf.new
6169 That will check for syntax errors without disturbing your running
6170 configuration. If you are paranoid enough, run, as \/root/\,
6172 ==> exim -C exim.conf.new <some address>
6176 and see if it delivers it. Carry on testing until happy. When happy,
6178 ==> mv exim.conf.new exim.conf
6179 kill -HUP `cat /var/spool/exim/exim-daemon.pid`
6181 Then check the Exim log to be sure the daemon restarted OK. Watch the
6182 log for a bit to see that mail is flowing.
6185 Q5026: Is exim able to use RFC 2645, \*On-demand Mail Relay*\ (ODMR)?
6190 Q5027: Is there any way I can send bounces to the postmaster, and nobody else?
6191 Basically, I want to receive them, and I don't want the reply/from
6192 person to get them. If I think they need it I will forward it myself.
6194 A5027: Put \"errors_to=postmaster"\ on every router.
6197 Q5028: When I HUP the Exim daemon, the name shown in the process table changes
6198 from \(/usr/lib/sendmail)\ (which is a symlink) to the real binary name.
6201 A5028: Add this to your Exim configuration:
6203 ==> exim_path = /usr/lib/sendmail
6206 Q5029: A message with a recipient address that contains a non-printing character
6207 is stuck on my mail queue. How can I remove this address?
6209 A5029: You can use the \-Mmd-\ command line option to mark a recipient address
6210 ``delivered'', which effectively removes it. If you are using the Bash
6211 shell, you can enter non-printing characters using an escape sequence.
6214 ==> exim -Mmd 15HKvU-00013Q-00 $'\240'abc@x.y.z
6216 In this example, the first character of the local part has a code value
6217 of 240. If you are using a shell that does not support this, create the
6218 command in a file and run it as a shell script.
6221 Q5030: I am using exim in a two queues scenario, with two different
6222 configuration files. How can I run a second copy of \^eximon^\ to
6223 inspect and modify the alternate queue?
6225 A5030: Use these commands (or put them in a script):
6227 ==> EXIMON_EXIM_CONFIG=/your/path/exim/configure.alternate
6228 export EXIMON_EXIM_CONFIG
6229 /your/path/exim/bin/eximon
6232 Q5031: Why is there no sender address on bounce messages? It shows up as "<>".
6234 A5031: See the answer to Q0042.
6237 Q5032: Are there any Exim web-based administration scripts?
6239 A5032: No (as far as is known). It seems likely that producing one that is
6240 generic enough would be a difficult task.
6243 Q5033: How can I send a copy of all outgoing messages to another mailbox?
6245 A5033: The most straightforward way is to set up a system filter, and include
6248 ==> unseen deliver mailbox@whatever.domain
6250 This sends a copy of every message to //mailbox@whatever.domain//
6251 (unless the message already has that recipient - Exim never does
6252 duplicate deliveries).
6254 To save only ``outgoing'' messages, you need to come up with a
6255 definition of what ``outgoing'' means. Typically, this might be a check
6256 on the sender address and/or on the originating host. Here is an
6259 ==> if $sender_address_domain is mydomain.com and
6260 ${mask:$sender_host_address/24} is 192.168.324.0/24
6262 unseen deliver mailbox@whatever.domain
6266 Q5034: Is there any way to make the \queue_only\ option conditional? I would
6267 like the ability to queue messages from external sources while deliver
6268 locally generated email as normal.
6270 A5034: There is no direct way of doing this. However, you can achieve the
6271 effect. In one of your ACLs that checks incoming mail from external
6274 ==> warn control = queue_only
6276 You can add other conditions as well, of course.
6282 Q9101: How can I install Exim on Mac OS X?
6284 A9101: (1) There is useful advice on this web page:
6285 \?http://www.afp548.com/Articles/Jaguar/exim410.html?\.
6287 (2) There is a package installer available at this URL:
6288 \?ftp://members.aol.com/AFP548dotcom/EximInstaller.sit?\.
6290 (3) There is another package installer for the combination of MySQL,
6291 Exim, Exiscan, CourierIMAP, and SpamAssassin at this URL:
6292 \?http://maxo.captainnet.net/installs/mail-install.html?\.
6298 Q9201: On FreeBSD, \(/usr/sbin/sendmail)\ is a symbolic link to
6299 \(/usr/sbin/mailwrapper)\; it doesn't contain the Sendmail binary. How
6300 should I replace Sendmail with Exim on FreeBSD?
6302 A9201: There is a file called \(/etc/mail/mailer.conf)\ which selects what to
6303 run for various MTA calls. Instead of changing \(/usr/sbin/sendmail)\,
6304 you should edit this file instead, to read something like this:
6306 ==> sendmail /usr/exim/bin/exim
6307 send-mail /usr/exim/bin/exim
6308 mailq /usr/exim/bin/exim -bp
6309 newaliases /usr/bin/true
6311 You probably also need to edit \(/etc/periodic.conf)\; see Q9202.
6314 Q9202: A script that FreeBSD runs nightly uses \^mailq^\ with the \-Ac-\
6315 parameter. Why doesn't Exim recognize this?
6317 A9202: \-Ac-\ is a Sendmail option that requests that mailq ``Show the mail
6318 submission queue specified in \(/etc/mail/submit.cf)\ instead of the
6319 MTA queue specified in \(/etc/mail/sendmail.cf)\''. Exim doesn't have
6320 the concept of a ``submission queue''. You can disable this feature
6321 of the nightly script by adding the line
6323 ==> daily_status_include_submit_mailq="NO" # No separate 'submit' queue
6325 to the file \(/etc/periodic.conf)\.
6328 Q9203: How can I use Exim for authenticated SMTP using Cyrus on FreeBSD?
6330 A9203: This web page may help: \?http://www.munk.nu/exim/exim-freebsd-asmtp.php?\.
6336 Q9301: I'm trying to compile on an HP machine and I don't have \^gcc^\ there. So I
6337 put \"CC=cc"\ in the \(Local/Makefile)\, but I got this error:
6339 ==> (Bundled) cc: "buildconfig.c", line 54: error 1705: Function prototypes
6340 are an ANSI feature.
6342 A9301: The bundled compiler is not an ANSI C compiler. You either have to get a
6343 copy of \^gcc^\ from the HPUX Software Porting Archives or buy the ANSI cc
6344 from HP. The advice given by one user of HP systems on the Exim
6345 mailing list was as follows:
6347 \*Personally, I wouldn't use anything but the ANSI C compiler. gcc
6348 works for compilation, but it doesn't know squat about PA-RISC chips
6349 past the 1.0 rev. Since then, HP has come out with PA-RISC 1.1, 2.0,
6350 and 2.1, each with better features. gcc will compile for them, but it
6351 doesn't produce anywhere near the optimization that HP's compiler
6354 \*I took the gcc road when we moved from FreeBSD to HP-UX because I was
6355 familiar with it. After 6 months, I had to go and re-port everything
6356 over when we realized that gcc wasn't going to do it for us long-term.
6357 If I could give advice to any new HP-UX admin: don't use gcc if you
6358 can afford the ANSI C compiler. Based on the cost of even the lowest
6359 HP workstation, that usually isn't a problem.*\
6365 Q9401: On BSDI 4.0, Exim built with Perl support exits with the error message
6367 ==> ./exim: can't load library 'libperl.so'
6369 A9401: You probably compiled perl5 yourself, without looking into
6371 ==> /usr/src/contrib/perl5/perl5.004_02/hints/bsdos.sh
6373 first. The problem is that the command
6375 ==> perl5 -MExtUtils::Embed -e ldopts
6377 doesn't give you sufficient flags to link something with libperl.
6378 Since 5.004_02 the \(hints/bsdos.sh)\ file has changed to adapt to the
6379 changes between BSDI 3.1 and 4.0, but it is still not entirely right.
6381 The solution is, when you compile perl, change the \ccdlflags\
6382 variable in config.sh to:
6384 ==> -rdynamic -Wl,-rpath,/usr/local/lib/perl5/5.00502/i386-bsdos/CORE
6386 (or something similar). Alternatively, you can run \(./Configure)\ and
6387 answering the question \*Any special flags to pass to cc to use dynamic
6388 loading?*\ with the above line. It is not known what \-rdynamic-\ means
6389 (it's not apparently documented in any man page), but that's what BSDI
6390 guys did to compile perl5 which comes with BSDI 4.0 distribution.
6396 Q9501: The IP addresses for incoming calls are all being given as
6397 255.255.255.255 or 0.0.0.0.
6399 A9501: This problem should no longer occur because a workaround has been
6406 Q9601: Exim is mysteriously crashing, usually when forking to send a delivery
6409 A9601: This has been seen in cases where Exim has been incorrectly built with
6410 a muddled combination of an \(ndbm.h)\ include file and a non-matching
6413 Faults like this have also been seen on systems with faulty motherboards.
6414 You could try to compile the Linux kernel 10 times - if the compile
6415 process stops with signal 11, your hardware is to blame.
6418 Q9602: I want to use \^logrotate^\ which is standard with RH5.2 Linux to rotate
6419 my mail logs. Anyone worked out the \^logrotate^\ config file that will
6422 A9602: Here's one suggestion:
6424 ==> /var/log/exim/main.log {
6425 create 644 exim exim
6431 The sleep is added to allow things to close the log file prior to
6432 compression. You also need similar entries for the panic log and the
6433 reject log, of course.
6436 Q9603: I'm seeing the message \*inetd[334]: imap/tcp server failing (looping),
6437 service terminated*\ on a RedHat 5.2 system, causing \^imap^\ connections to
6438 be refused. The \^imapd^\ in use is Washington Univers 12.250. Could this
6439 be anything to do with Exim?
6441 A9603: No, it's nothing to do with Exim, but here's the answer anyway: there
6442 is a maximum connection rate for \^inetd^\. If connections come in faster
6443 than that, it thinks a caller is looping. The default setting on RedHat
6444 5.2 is 40 calls in any one minute before \^inetd^\ thinks there's a problem
6445 and suspends further calls for 10 mins. This default setting is very
6446 conservative. You should probably increase it by a factor of 10 or 20.
6449 ==> imap stream tcp nowait.400 root /usr/sbin/tcpd /usr/local/etc/imapd
6451 The rate setting is the number following ``nowait''. This syntax seems to
6452 be specific to the Linux version of \^inetd^\. Other operating systems
6453 provide similar functionality, but in different ways.
6456 Q9604: I get the \*too many open files*\ error especially when a lot of messages
6457 land for Majordomo at the same time.
6459 A9604: The problem appears to be the number of open files the system can
6460 handle. This is changable by using the proc filesystem. To your
6461 \(/etc/rc.d/rc.local)\ file append something like the following:
6463 ==> # Now System is up, Modify kernel parameters for max open etc.
6465 ==> if [ -f /proc/sys/kernel/file-max ]; then
6466 echo 16384 >> /proc/sys/kernel/file-max
6468 if [ -f /proc/sys/kernel/inode-max ]; then
6469 echo 24576 >> /proc/sys/kernel/inode-max
6471 if [ -f /proc/sys/kernel/file-nr ]; then
6472 echo 2160 >> /proc/sys/kernel/file-nr
6475 By echoing the value you want for file-max to the file \(file-max)\ etc.,
6476 you actually change the kernel parameters.
6479 Q9605: I installed debian 2.2 linux on a small 325mb 486 laptop. When I try
6480 to test the Mail program, I get the following error: \*Failed to open
6481 configuration file /etc/exim.conf*\.
6483 A9605: The Debian installation should have given you \(/usr/sbin/eximconfig)\,
6484 which asks you some questions and then sets up the configuration file
6485 in \(/etc/exim.conf)\. Try running that (you'll probably need \/root/\) and see
6486 how it goes. In any case you get a thoroughly commented conf file at
6487 the end, which will give you a sample from which to work if you need
6488 further modification.
6490 The Exim docs in the Debian package are in \(/usr/doc/exim)\ where the full
6491 reference manual is \(spec.txt.gz)\.
6494 Q9606: I'm having trouble configuring Exim 4 on a Debian system. How does
6495 \(/etc/exim4/conf.d)\ work?
6497 A9606: The Debian Exim 4 package uses a quite uncommon, but elegant,
6498 method of configuration where the ``real'' Exim configuration file is
6499 assembled from a tree of snippets by a script invoked just before the
6500 daemon is started (see Q9608).
6502 This fits very well into the Debian system of configuration file
6503 management and is a great ease for the automatic configuration with
6504 Debconf. However, it is \*very*\ different from the normal way Exim 4 is
6505 configured. Non-Debian users on the Exim mailing list will probably have
6506 difficulty in trying to answer specific questions about it. You may have
6507 to find a Debian expert.
6510 Q9607: I'm having difficulties trying to make Exim 4 with Redhat 9 and Berkeley
6513 A9607: Have you remembered to install the db4-devel package?
6516 Q9608: I'm running Exim 3 under Debian, and want to upgrade to Exim 4. How
6519 A9608: A user who did this, using the Debian Exim 4 package, reported as
6522 (1) The exim4 package installs easily, and the exim (3.38) package
6523 uninstalls at the same time.
6525 (2) Exim runs from \^inetd^\. Exim4 runs from \^/etc/init.d^\. \*Much*\ nicer!
6527 (3) The exim conffile lives in \(/etc/exim/exim.conf)\. The exim4 conffile
6528 lives in \(/var/lib/exim4/config.autogenerated)\. It is, as the name
6529 suggests, autogenerated.
6531 (4) A new directory is created called \(/etc/exim4)\. This contains the
6532 conffiles to generate the above config. You make changes here.
6534 (5) Once you have made changes to the files in \(/etc/exim4)\ you run the
6535 script \^update-exim4.conf^\ which generates a replacement
6536 \(config.autogenerated)\.
6538 [Added comment by the Debian maintainer, slightly edited:
6539 You also need to tell the Exim daemon to reread the changed
6540 configuration. You can do this using SIGHUP by hand. Alternatively,
6541 instead of running \^update-exim4.conf^\ you can use
6543 ==> invoke-rc.d exim4 reload
6545 which does the rebuild and also tells Exim to reread the changed
6548 (6) In my experience, you need to \*carefully*\ check the generated
6549 configs. eg, it did not generate a system filter file reference in the
6550 \(config.autogenerated)\. I didn't bother too much, since this is a home
6553 (7) All of this may be in the docs. I've read some of them, obviously,
6554 but didn't come across an actual upgrade guide.
6556 [The Debian maintainer says:
6557 \(/usr/share/doc/exim4-base/README.Debian.gz)\ and \^update-exim4.conf(8)^\
6558 should answer most of the questions.]
6560 (8) I've still got some minor things to tweak to get back to where I
6561 was before with Exim 3. But overall, it's no drama.
6564 Q9609: Why do some servers refuse SMTP connections from my Linux box, but accept
6565 connections from hosts running other operating systems?
6567 A9609: If you are sure this isn't a policy issue (that is, your box isn't
6568 administratively blocked for some reason), this may be because your
6569 Linux box has ECN (Explicit Congestion Notification) enabled in its
6570 TCP/IP stack. There are many broken firewalls that refuse connections
6571 from ECN-enabled hosts. You can check the state of your box by running
6573 ==> cat /proc/sys/net/ipv4/tcp_ecn
6575 If the value is "1", you have ECN enabled. You can turn it off by
6576 running this command:
6578 ==> echo "0" > /proc/sys/net/ipv4/tcp_ecn
6584 Q9701: Exim builds fine with \^gcc^\ on SunOS 4 but crashes inside \^^sscanf()^^\.
6586 A9701: Make sure you are liking with the GNU \^ld^\ linker and not the system
6590 Q9702: How can I get rid of spurious \"^M"\ characters in messages sent from
6593 A9702: CDE \^dtmail^\ passes messages to Exim via the command line interface with
6594 lines terminated by CRLF, instead of the Unix convention of just LF. As
6595 Exim is an 8-bit clean program it treats the CR as just another data
6596 character. Exim has a command line option called \-dropcr-\ which causes
6597 it to ignore all CR characters in an incoming non-SMTP message. You
6598 should configure \^dtmail^\ to add this option to the command it uses to
6599 call Exim (using the path \(/usr/lib/sendmail)\). However, it has been
6600 reported that it isn't possible to change this call from \^dtmail^\ by any
6601 official means. An alternative approach is to replace \(/usr/lib/sendmail)\
6602 by a filtering script which removes the spurious CRs from the input
6603 before passing it to Exim.
6606 Q9703: On SunOS 4 Exim crashes when looking up domains in the DNS that have
6607 more than 10 A records.
6609 A9703: There are Sun library patches to fix this. It is not Exim's problem.
6610 For 4.13_U1 the patch is 101558-xx; for 4.1.3 the patch is 100891-xx.
6611 From the README: \*1054748 ftp, ping dump core when connecting to a host
6612 with multiple DNS A records.*\ An alternative is to build another
6613 resolver library - such as the ones that are part of the \^bind^\
6614 distribution - and explicitly link against those.
6617 Q9704: I am experiencing mailbox locking problems with Sun's \^mailtool^\ used
6620 A9704: Under the \"Expert"\ settings of \^mailtool^\ is a option to turn on \*Use
6621 network aware mail file locking*\. By default \^dtmail^\ has this set, but
6622 \^mailtool^\ doesn't. You should set it. The help info on \^dtmail^\ has this
6625 \*Mailer tries to prevent two different instances of itself from opening
6626 the same mail file at the same time through a technique that detects
6627 this access when both instances of Mailer and the file are all on the
6628 same machine. A network-aware mail file locking protocol is available
6629 that uses ToolTalk to coordinate instances of Mailer running from more
6630 than one machine, or mail files accessed over the network. Mailer can
6631 only change this option when first opening a mail file.*\
6633 If you are using the SunOS4 version of \^mailtool^\, this apparently
6634 doesn't work. The only thing which does seem to work it getting the user
6635 to hit the \"done"\ button to make it release the lock.
6638 Q9705: Exim has been crashing on my Solaris x86 system, apparently while
6639 running DBM functions.
6641 A9705: The use of \^ndbm^\ with \^gcc^\ has caused problems on x86 Solaris systems.
6642 Try changing one or the other; using either DB with gcc, or Sun's
6643 WS compiler with \^ndbm^\, has fixed this in the past.
6646 Q9706: The \^exiwhat^\ utility isn't working for me on a Solaris 2 system.
6648 A9706: Have you got \(/usr/ucb)\ on your path? If so, it is probably picking up the
6649 wrong version of the \^ps^\ command. The \^exiwhat^\ script is built on
6650 Solaris to expect the normal Solaris version of \^ps^\.
6653 Q9707: How do I stop Sun's \^dtcm^\ from hanging?
6655 A9707: From qmail's FAQ: \*There is a novice programming error in dtcm, known as
6656 ``failure to close the output side of the pipe in the child.'' Sun has,
6657 at the time of this writing, not yet provided a patch.*\
6660 Q9708: I want Exim to use only the resolver (i.e. ignore \(/etc/hosts)\), but don't
6661 want to alter the \(nsswitch.conf)\ file in Solaris 2.
6663 A9708: You need to rebuild Exim after fiddling with \(OS/os.h-SunOS5)\:
6665 ==> #define gethostbyaddr res_gethostbyaddr
6666 #define gethostbyname res_gethostbyname
6667 #define endhostent res_endhostent
6668 #define endnetent res_endnetent
6669 #define gethostent res_gethostent
6670 #define getnetbyaddr res_getnetbyaddr
6671 #define getnetbyname res_getnetbyname
6672 #define getnetent res_getnetent
6673 #define sethostent res_sethostent
6674 #define setnetent res_setnetent
6676 Note that \-lnsl-\ is still needed in the Makefile as it
6677 contains code used by the NIS lookup and also the \^^inet_addr()^^\ function
6681 Q9709: When I try to compile Exim 4.x on Solaris 2.5.1 I get an error along the
6682 lines of \*no such field in struct as 'value.ui32'*\.
6684 A9709: Look in the Exim file \(OS/os.h-SunOS5.h)\ for the line
6686 ==> #define LOAD_AVG_FIELD value.ui32
6688 and change \"ui32"\ to \"ul"\ (that's u followed by the letter ell, not
6689 the digit one). Solaris 2.5.1 is getting \*very*\ old now...
6693 98. CONFIGURATION COOKBOOK
6695 Q9801: How do I configure Exim as part of TPC (\?http://www.tpc.int?\)?
6697 A9801: Suppose you want to accept faxes destined for 1(801)539-*. These are
6698 addressed to the domain //9.3.5.1.0.8.1.tpc.int//. Set up a transport to
6699 handle the delivery:
6703 command = /usr/local/tpc/tpcmailer.pl $local_part@$domain \
6707 \(/usr/local/tpc/tpcmailer.pl)\ is the mail processing script that can
6708 be obtained from the TPC distribution. Create a router to route mail
6709 for the TPC domain to that transport. This must be placed before your
6715 domains = *.9.3.5.1.0.8.1.tpc.int
6717 Of course, there are other things to do as well before your system is
6718 a functioning TPC server.
6721 Q9802: How do I configure Exim so that it sends mail to the outside world only
6722 from a restricted list of our local users?
6724 A9802: You will need to have a convenient way of checking the list. If it is
6725 only a handful of users, you could just list them inline. Otherwise, you
6726 need to put them in a file or database. Let's suppose you've just got a
6727 list in a file. Put this as your first router:
6731 domains = ! +local_domains
6732 senders = ! : ! lsearch;/etc/permitted/senders
6734 data = :fail: you are not allowed to send outside
6736 The senders should be listed as complete addresses, with both a local
6737 part and a domain. For a large list, use a DBM or cdb file instead, or
6738 a database. The first item in the \senders\ list is empty, to match the
6739 empty sender. This is necessary because bounce messages have null
6743 Q9803: A site for which I provide secondary MX is down for some time. Is there
6744 a way to run the queue for that destination separately from the main
6747 A9803: No, because Exim does not have the concept of ``the queue for that
6748 destination''. It simply has a single pool of messages awaiting delivery
6749 (and some of them may have several destinations). The best approach to
6750 this is to arrange for all messages for the site to be saved somewhere
6751 other than the main spool, either on a separate dedicated MTA, or in
6755 Q9804: We want to be able to temporarily lock out a user by disabling the
6756 password and moving the home directory to another place. How can we
6757 arrange to reject mail for users in this state?
6759 A9804: Change the home directory pointer in the passwd file to something
6760 distinctive. For example, we use \(/home/CANCELLED)\ for cancelled users.
6761 Then you can pick up such users with this router, which is placed
6762 immediately after \%system_aliases%\:
6764 ==> cancelled_users:
6767 condition = ${if eq {$home}{/home/CANCELLED}{yes}{no}}
6769 data = :fail: this account is cancelled
6772 Q9805: How can I configure Exim so that all mails addressed to
6773 //something@username.domain.net// get delivered to
6774 \(/var/spool/mail/username)\?
6776 A9805: Assuming that you have set up //username// as a normal user, with
6777 conventional routing for //username@domain.net// to that mailbox, all
6778 you need to do is set up a redirection, using a router like this:
6782 data = ${if match{$domain}{\N^(.*)\.domain\.net$\N}\
6783 {$1}fail}@domain.net
6785 If you set \envelope_to\ in the \%appendfile%\ transport, the original
6786 envelope address is preserved in the message in an ::Envelope-to::
6790 Q9806: How do I get exim not to add a ::Sender:: header to locally originated
6793 A9806: It adds it only if the ::From:: header doesn't correspond to the user
6794 sending the message. You can suppress this by setting
6795 \no_local_from_check\. If your real question is \*How do I submit mail
6796 from UUCP without it adding ::Sender::?*\, see Q1503.
6799 Q9807: Is there any way to have messages sent to a specific local address
6800 delayed by - say - 24 hours?
6802 A9807: Set up a router like this:
6806 domains = the.domain
6807 local_parts = thelocalpart
6808 condition = ${if < {$message_age}{86400}{yes}{no}}
6810 data = :defer: message not old enough
6813 Of course, this will also have the effect of setting a retry time for
6814 the address. You may want to set a special retry rule for it. Note the
6815 use of \no_verify\ to ensure that this router is not used when Exim is
6816 verifying addresses.
6819 Q9808: I have a mailing list exploder on one host, and three other hosts where
6820 I want to do the actual deliveries from. How can I get Exim to split
6821 a message into groups of recipients between the three hosts?
6823 A9808: Set up a router that routes all remote addresses to a specific
6824 transport, with a list of your three hosts. For example:
6827 driver = manualroute
6828 transport = to_three_smtp
6829 route_list = !+local_domains hostA:hostB:hostC
6831 The transport looks like this:
6837 By setting \hosts_randomize\, you request that the host list be sorted
6838 randomly each time the transport is called, in order to spread the load.
6839 The number of times the transport is called for each message depends on
6840 the setting of the global option \remote_max_parallel\. If it is set to
6841 1, the transport is called only once for each message, so only one host
6842 is used, but different messages use different hosts because of the
6845 The \max_rcpt\ option (default 100) controls the number of addresses
6846 sent in each copy of the message - several copies are sent over the
6847 same connection if necessary.
6849 If you want individual messages to be split between the three hosts, you
6850 must set the global option \remote_max_parallel\ to 3. This allows Exim
6851 to run 3 separate instances of the transport at once. It will pass
6852 one-third of all the addresses to each instance. Because the host list
6853 is randomized, not round-robinned, there is no guarantee that a single
6854 message will use all three hosts, but on average it should.
6857 Q9809: Can I configure Exim so that my gateway host sends a copy of each
6858 incoming message to each of two internal hosts?
6860 A9809: The easiest way to do this is to make use of the \unseen\ router option,
6861 and set up two separate routers. You need to be able to identify
6862 incoming messages somehow. Typically this can be done by testing the
6863 domain of the recipient address, in which case the configuration should
6864 contain something like this:
6867 driver = manualroute
6868 domains = ! *.your.domain.example
6869 route_data = * host1.your.domain.example
6870 transport = remote_smtp
6874 driver = manualroute
6875 domains = ! *.your.domain.example
6876 route_data = * host2.your.domain.example
6877 transport = remote_smtp
6879 The \unseen\ setting on \%r1%\ means that after it has accepted an
6880 address, the address is also passed on to \%r2%\, and so two deliveries
6884 Q9810: How can I implement ``SMTP-after-POP'' with Exim?
6889 Q9811: I would like to ``tap off'' a proportion of real mail traffic from my
6890 live mail server to use in tests of a new server. I want to preserve the
6891 envelope contents, but to suppress any error notifications to the
6897 Q9812: How can I lookup data from a single file using both single IP addresses
6898 and IP address blocks as keys? I want to set \smtp_accept_max_per_host\
6899 by this means, and also include a default.
6901 A9812: You cannot do this in a single lookup, because you need separate lookups
6902 for individual addresses and address blocks. However, these lookups can
6903 be nested in a single expansion string. For example, suppose you are
6904 using an lsearch file with entries like this:
6906 ==> 192.168.34.35: 4
6910 You can use this setting:
6912 ==> smtp_accept_max_per_host = \
6913 ${lookup{$sender_host_address}lsearch{/path/to/file}\
6916 ${lookup{${mask:$sender_host_address/24}}lsearch*{/path/to/file}}\
6919 Note that the first lookup does \*not*\ have an asterisk on the search
6920 type. If you have blocks of different sizes (/24, /26, etc) you have to
6921 configure it to do a separate lookup for each size, with just the final
6922 one using a default.
6926 99. LIST OF SAMPLE CONFIGURATIONS
6928 As well as being hyperlinked from the HTML version of this document, each
6929 sample configuration is also available as a file in the \(config.samples)\
6930 directory, which can be independently downloaded.
6932 Samples whose names are of the form Cnnn are Exim configurations; those with
6933 names of the form Fnnn are filter file fragments; those with names of the form
6934 Lnnn are sample \^^local_scan()^^\ functions, and those with names of thf form
6935 Snnn are scripts of various kinds. There are other examples of
6936 \^^local_scan()^^\ functions at a number of web sites (for example,
6937 \?http://marc.merlins.org/linux/exim/sa.html?\).
6939 There are gaps in the C and F numbers because I have omitted the Exim 3 samples
6940 that have not been converted for Exim 4.
6942 C002: ``Although exim not intended for use in UUCP environment (it doesn't
6943 know anything about bang!path addresses), I'm successfully using it for
6944 delivering mail to UUCP clients.''
6946 C006: ``This is how I have configured a PP-inspired vacationnote, there is
6947 (was?) such a feature in PP. The user makes a file \(tripnote)\ in his/her
6948 home directory, the message is passed to the sender once with a short
6951 C022: ``This is the Exim configuration file of a machine which delivers mail to
6952 several local domains where the mail is delivered locally, several hairy
6953 domains, handled as described below, and a half-virtual domain, which is
6954 first processed by its special alias file, then processed as other local
6955 domains (including the processing by the global alias file).''
6957 C037: An elegant way of using ETRN, which does immediate delivery if the host
6958 is online, but saves mail in a BSMTP file after some time on the queue.
6959 ETRN then re-injects the mail.
6961 C042: ``Since the Exim 4 configuration needed to get Mailman to work differs a
6962 little bit from Exim 3 and since I still haven't seen a recipe for
6963 Mailman with Exim 4, I'm providing my configuration (based heavily on
6964 \?http://www.exim.org/howto/mailman.html?\).''
6966 C043: ``Attached is an Exim 4 config file which is designed for an Exim server
6967 that is put in front of an Exchange 5.5 system but which verifies the
6968 valid addresses that are stored in Exchange via LDAP lookups against the
6971 C044: ``I thought I'd submit this as an example of an authenticated mail hub
6972 configuration. Several people have asked for it so I thought it
6973 might be of interest.''
6975 C045: ``Here it is, for Exim 4.10 and Cyrus IMAPD 2.1.5 using db3/db4-format
6976 mailbox database. This configuration delivers the messages to Cyrus
6977 IMAPD using LMTP over a TCP/IP socket.''
6979 C046: ``Deliver a duplicate of some proportion of all messages to a special
6980 machine specified in the file \(/MAIL_TAP_HOST)\, if it exists.''
6982 C047: A sample configuration for calling Spamassassin directly from Exim.
6984 C049: ``I've been seeing a whole bunch of IPs that send me spam or virus mail
6985 and HELOing as one of my own IPs, or as HELO one.of.my.own.domains (or
6986 maybe HELO \primary_hostname\).''
6988 C050: A configuration that uses the DNS to implement virtual domains.
6990 C051: ``I've been working quite hard to come up with a config that reasonably
6991 matches the qmail-ldap setup, without the warts.''
6993 F001: ``I thought that the rest of the list may be interested in reviewing our
6994 filter as a starting point for their own system message filter.''
6996 F002: ``... program which refused mail from unknown addresses until they mailed
6997 me promising not to spam me ... since I'd already thought through how
6998 to do it in Exim, and knew it'd be slightly easier than falling out of
6999 bed, I went ahead and did it.''
7001 F003: ``Here's four checks installed in our system wide filter that knock out
7002 a lot of otherwise hard to detect rubbish.''
7004 F004: ``This is an Exim filter snippet to change locally-generated ::Message-Id::
7005 and ::Resent-Message-Id:: headers to world-unique values.''
7007 L001: A \^^local_scan()^^\ function for Exim that calls \^uvscan^\.
7009 S001: A Perl script for patching the name of the configuration file in an
7012 S002: ``When I moved from smail to exim I built a program that took individual
7013 config pieces, stripped all the comments, and built a config file.''
7015 *** End of Exim FAQ ***
git://git.exim.org / users / heiko / exim.git / blob