1 . $Cambridge: exim/doc/doc-src/spec.src,v 1.2 2005/01/11 15:17:51 ph10 Exp $
4 .set previousversion "4.40"
5 .set versionmonth "January"
6 .set versionyear "2005"
9 . The last of those is to make ACL index entries easier to type. It is put
10 . up here so that it gets picked up by the HTML converter, which otherwise
11 . skips to the first chapter. A longer version is set below for use in the
20 .linelength ~~sys.linelength + 0.2in
21 .set newlinelength ~~sys.linelength
22 .emphasis ~~sys.linelength + 0.1in
23 .pagedepth ~~sys.pagedepth - 0.2in
24 .bindfont 51 "atl/Times-Bold" 9
25 .bindfont 52 "atl/Times-Roman" 9
26 .bindfont 53 "atl/Times-Roman" 7
27 .bindfont 54 "atl/Courier" 9
28 .bindfont 55 "atl/Courier-Bold" ~~maintypesize
29 .bindfont 56 "atl/Times-Italic" 7
30 .bindfont 57 "atl/Times-Bold" 7
31 .bindfont 58 "atl/Symbol" 7
35 . Used for the "small print" incorporated code stuff. Only rm, it, bf, sp are
36 . actually used at present.
37 . rm it sl bf bi ss tt sp sc
38 .fontgroup 9 = 53 56 0 57 0 0 0 58 0
43 .fontgroup 9 = 0 0 0 0 0 0 0 0 0
49 .flag $smc{ "$push$g0$f54"
50 .flag $sm{ "$push$g0$f53"
51 .flag $smi{ "$push$g0$f56"
52 .flag $as{ "$push$g0$f52"
53 .flag $ab{ "$push$g0$f51"
54 .flag $cb{ "$push$g0$f55"
63 .macro isunderscore "string"
65 .set length length "~~1"
69 .macro undrec "offset"
73 .set sub "~~string"(1,~~1)
83 .macro testunderscore "string"
112 .macro option "option" ""
114 .index \-~~1-\ option
131 .macro item "item" "6"
133 .if ~~sys.leftonpage < ~~2ld
158 .macro conf "option" "type" "default" "6"
160 .if ~~sys.leftonpage < ~~4ld
163 .testunderscore "~~1"
170 \**~~1**\ $c $rm{Type:} $it{~~2} $e $rm{Default:} $it{~~3}
176 .set displayindent 2em
178 .index @$1, @$2, etc. $it{see numerical variables}
179 .index address||rewriting $it{see rewriting}
180 .index CR character $it{see carriage return}
181 .index CRL $it{see certificate revocation list}
182 .index delivery||failure report $it{see bounce message}
183 .index dialup $it{see intermittently connected hosts}
184 .index exiscan $it{see content scanning}
185 .index failover $it{see fallback}
186 .index fallover $it{see fallback}
187 .index filter||Sieve $it{see Sieve filter}
188 .index ident $it{see RFC 1413}
189 .index LF character $it{see linefeed}
190 .index maximum $it{see limit}
191 .index NUL $it{see binary zero}
192 .index process id $it{see pid}
193 .index RBL $it{see DNS list}
194 .index redirection $it{see address redirection}
195 .index return path||$it{see also envelope sender}
196 .index scanning $it{see content scanning}
197 .index SSL $it{see TLS}
198 .index string||expansion $it{see expansion}
199 .index top bit $it{see 8-bit characters}
200 .index variables $it{see expansion, variables}
201 .index zero, binary $it{see binary zero}
203 . This is used for the printed index. See setting above for
204 . the HTML index value.
206 .set ACL "access control lists (ACLs)"
208 . ======================================================
215 $chead{University of Cambridge Computing Service}
217 $chead{Specification of the Exim Mail Transfer Agent}
222 .space ~~sys.leftonpage - 15*~~sys.linedepth
224 University Computing Service
231 $it{phone:} $t +44 1223 334600
232 $it{fax:} $t +44 1223 334679
233 $it{email:} $t ph10 $it{at} cus.cam.ac.uk
235 Edition for Exim ~~version, ~~versionmonth ~~versionyear
240 $c$rm{Copyright (c) University of Cambridge ~~versionyear}
251 . Blank verso for title page
256 . Set up for actual text pages
258 . The first one to prevent a warning from sgfr
259 . set runningfoot "~~chapter"
265 .if "~~runningfoot" == ""
268 .set rhs "~~runningfoot (~~chapter)"
270 .set lhs "Exim ~~version"
271 .linelength ~~newlinelength
272 $it{~~lhs}$c[~~sys.pagenumber]$e$it{~~rhs}
283 . ============================================================================
284 .chapter Introduction
285 .set runningfoot "introduction"
288 $c$bi{If I have seen further it is by standing on the shoulders of giants.}##(Isaac Newton)
290 $c"If I have seen further it is by standing on the shoulders of giants."
294 \*If I have seen further it is by standing on the shoulders of giants.*\
299 Exim is a mail transfer agent (MTA) for hosts that are running Unix or
300 Unix-like operating systems. It was designed on the assumption that it would be
301 run on hosts that are permanently connected to the Internet. However, it can be
302 used on intermittently connected hosts with suitable configuration adjustments.
304 Configuration files currently exist for the following operating systems: AIX,
305 BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, FreeBSD, GNU/Hurd, GNU/Linux,
306 HI-OSF (Hitachi), HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD, QNX, SCO, SCO
307 SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4, Tru64-Unix (formerly
308 Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware. Some of these operating
309 systems are no longer current and cannot easily be tested, so the configuration
310 files may no longer work in practice.
312 There are also configuration files for compiling Exim in the Cygwin environment
313 that can be installed on systems running Windows. However, this document does
314 not contain any information about running Exim in the Cygwin environment.
316 The terms and conditions for the use and distribution of Exim are contained in
317 the file \(NOTICE)\. Exim is distributed under the terms of the GNU General
318 Public Licence, a copy of which may be found in the file \(LICENCE)\.
320 The use, supply or promotion of Exim for the purpose of sending bulk,
321 unsolicited electronic mail is incompatible with the basic aims of the program,
322 which revolve around the free provision of a service that enhances the quality
323 of personal communications. The author of Exim regards indiscriminate
324 mass-mailing as an antisocial, irresponsible abuse of the Internet.
326 Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
327 experience of running and working on the Smail 3 code, I could never have
328 contemplated starting to write a new MTA. Many of the ideas and user interfaces
329 were originally taken from Smail 3, though the actual code of Exim is entirely
330 new, and has developed far beyond the initial concept.
332 Many people, both in Cambridge and around the world, have contributed to the
333 development and the testing of Exim, and to porting it to various operating
334 systems. I am grateful to them all. The distribution now contains a file called
335 \(ACKNOWLEDGMENTS)\, in which I have started recording the names of
338 .section Exim documentation
340 This edition of the Exim specification applies to version ~~version of Exim.
341 Substantive changes from the ~~previousversion edition are marked by bars in
342 the right-hand margin in the PostScript, PDF, and plain text versions of the
343 document, and by green text in the HTML version, as shown by this paragraph.
344 Changes are not marked in the Texinfo version, because Texinfo doesn't support
345 change bars. Minor corrections and rewordings are not marked.
347 This document is very much a reference manual; it is not a tutorial. The reader
348 is expected to have some familiarity with the SMTP mail transfer protocol and
349 with general Unix system administration. Although there are some discussions
350 and examples in places, the information is mostly organized in a way that makes
351 it easy to look up, rather than in a natural order for sequential reading.
352 Furthermore, the manual aims to cover every aspect of Exim in detail, including
353 a number of rarely-used, special-purpose features that are unlikely to be of
356 .index books about Exim
357 An `easier' discussion of Exim which provides more in-depth explanatory,
358 introductory, and tutorial material can be found in a book entitled
360 [(A HREF="http://www.uit.co.uk/exim-book/")]
361 $it{The Exim SMTP Mail Server},
363 published by UIT Cambridge.
365 $it{The Exim SMTP Mail Server}, published by UIT Cambridge
366 (\?http://www.uit.co.uk/exim-book/?\).
369 This book also contains a chapter that gives a general introduction to SMTP and
370 Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
371 with the latest release of Exim. (Note that the earlier book about Exim,
372 published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
374 .index \(doc/NewStuff)\
375 .index \(doc/ChangeLog)\
377 As the program develops, there may be features in newer versions that have not
378 yet made it into this document, which is updated only when the most significant
379 digit of the fractional part of the version number changes. However,
380 specifications of new features that are not yet in this manual are placed in
381 the file \(doc/NewStuff)\ in the Exim distribution. All changes to the program
382 (whether new features, bug fixes, or other kinds of change) are noted briefly
383 in the file called \(doc/ChangeLog)\.
385 .index \(doc/spec.txt)\
386 This specification itself is available as an ASCII file in \(doc/spec.txt)\ so
387 that it can easily be searched with a text editor. Other files in the \(doc)\
391 \(OptionLists.txt)\ $t $rm{list of all options in alphabetical order}
392 \(dbm.discuss.txt)\ $t $rm{discussion about DBM libraries}
393 \(exim.8)\ $t $rm{a man page of Exim's command line options}
394 \(filter.txt)\ $t $rm{specification of the filter language}
395 \(pcrepattern.txt)\ $t $rm{specification of PCRE regular expressions}
396 \(pcretest.txt)\ $t $rm{specification of the PCRE testing program}
397 \(Exim3.upgrade)\ $t $rm{upgrade notes from release 2 to release 3}
398 \(Exim4.upgrade)\ $t $rm{upgrade notes from release 3 to release 4}
400 The main specification and the specification of the filtering language are also
401 available in other formats (HTML, PostScript, PDF, and Texinfo). Section
402 ~~SECTavail below tells you how to get hold of these.
405 .section FTP and web sites, and mailing list
408 The primary distribution site for Exim is an FTP site, whose contents are
409 described in \*Where to find the Exim distribution*\ below. In addition,
410 there is a web site at \?http://www.exim.org?\ by courtesy of Energis Squared,
411 formerly Planet Online Ltd, who are situated in the UK. The site is mirrored in
412 a number of other countries; links to the mirrors are listed on the home page.
413 The web site contains the Exim distribution, and you can also find the
414 documentation and the
417 [(A HREF="FAQ.html")]
423 online there, as well as other relevant material.
425 .index mailing lists||for Exim users
426 Energis Squared also provide resources for the following mailing lists:
429 $it{exim-users@@exim.org} $t general discussion list
430 $it{exim-announce@@exim.org} $t moderated, low volume announcements list
432 You can subscribe to these lists, change your existing subscriptions, and view
433 or search the archives via the
435 [(A HREF="http://www.exim.org/maillist.html")]
441 link on the Exim home page. The $it{exim-users} mailing list is also forwarded
442 to \?http://www.egroups.com/list/exim-users?\, an archiving system with
443 searching capabilities.
445 .section Exim training
446 .index training courses
447 From time to time (approximately annually at the time of writing),
448 lecture-based training courses are run by the author of Exim in Cambridge, UK.
449 Details can be found on the web site
451 [(A HREF="http://www-tus.csx.cam.ac.uk/courses/exim/")]
453 \?http://www-tus@.csx@.cam@.ac.uk/courses/exim/?\.
460 .index reporting bugs
461 Reports of obvious bugs should be emailed to \*bugs@@exim.org*\. However, if
462 you are unsure whether some behaviour is a bug or not, the best thing to do is
463 to post a message to the $it{exim-users} mailing list and have it discussed.
466 .section Where to find the Exim distribution
467 .rset SECTavail "~~chapter.~~section"
469 .index distribution||ftp site
470 The master ftp site for the Exim distribution is
475 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim?\
477 Within that directory there are subdirectories called \(exim3)\ (for previous
478 Exim 3 distributions), \(exim4)\ (for the latest Exim 4 distributions), and
479 \(Testing)\ for occasional testing versions. Those mirror sites that I know
480 about are listed in the file
485 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/Mirrors?\
487 In the \(exim4)\ subdirectory, the current release can always be found in
490 \(exim-$it{n.nn}.tar.gz)\
491 \(exim-$it{n.nn}.tar.bz2)\
493 where $it{n.nn} is the highest such version number in the directory. The two
494 files contain identical data; the only difference is the type of compression.
495 The \(.bz2)\ file is usually a lot smaller than the \(.gz)\ file.
496 .index distribution||signing details
497 .index distribution||public key
498 .index public key for signed distribution
499 The distributions are signed with Philip Hazel's GPG key.
500 The corresponding public key is available from a number of keyservers, and
501 there is also a copy in the file:
506 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/Public-Key?\
508 The signatures for the tar bundles are in:
510 \(exim-$it{n.nn}.tar.gz.sig)\
511 \(exim-$it{n.nn}.tar.bz2.sig)\
514 When there is only a small amount of change from one release to the next, a
515 patch file may be provided, with a final component name of the form
517 \(exim-patch-$it{n.nn}-$it{m.mm}.gz)\
519 For each released version, the log of changes is made separately available in
522 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/ChangeLogs?\
524 so that it is possible to find out what has changed without having to download
525 the entire distribution.
527 .index documentation||available formats
528 The main distribution contains ASCII versions of this specification and other
529 documentation; other formats of the documents are available in separate files
530 inside the \(exim4)\ directory of the FTP site:
532 \(exim-html-$it{n.nn}.tar.gz)\
533 \(exim-pdf-$it{n.nn}.tar.gz)\
534 \(exim-postscript-$it{n.nn}.tar.gz)\
535 \(exim-texinfo-$it{n.nn}.tar.gz)\
537 These tar files contain only the \(doc)\ directory, not the complete
538 distribution, and are also available in \(.bz2)\ as well as \(.gz)\ forms.
541 The FAQ is available for downloading in two different formats from
546 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4/FAQ.txt.gz?\
547 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4/FAQ.html.tar.gz?\
549 The first of these is a single ASCII file that can be searched with a text
550 editor. The second is a directory of HTML files, normally accessed by starting
551 at \(index.html)\. The HTML version of the FAQ (which is also included in the
552 HTML documentation tarbundle) includes a keyword-in-context index, which is
553 often the most convenient way of finding your way around.
557 A wish list is maintained, containing ideas for new features that have been
558 submitted. From time to time the file is exported to the ftp site:
560 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4/WishList?\
562 Items are removed from the list if they get implemented.
565 .section Contributed material
566 .index contributed material
567 At the ftp site, there is a directory called
572 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4/Contrib/?\
574 which contains miscellaneous files contributed to the Exim community by Exim
575 users. There is also a collection of contributed configuration examples in
580 \?ftp://ftp.csx.cam.ac.uk/pub/software/email/exim/exim4/config.samples.tar.gz?\
582 These samples are referenced from the FAQ.
586 .index limitations of Exim
588 Exim is designed for use as an Internet MTA, and therefore handles addresses
589 in RFC 2822 domain format only.
590 .index bang paths||not handled by Exim
591 It cannot handle UUCP `bang paths', though simple two-component bang paths can
592 be converted by a straightforward rewriting configuration. This restriction
593 does not prevent Exim from being interfaced to UUCP as a transport mechanism,
594 provided that domain addresses are used.
596 .index domainless addresses
597 .index address||without domain
598 Exim insists that every address it handles has a domain attached. For incoming
599 local messages, domainless addresses are automatically qualified with a
600 configured domain value. Configuration options specify from which remote
601 systems unqualified addresses are acceptable. These are then qualified on
604 .index transport||external
605 .index external transports
606 The only external transport currently implemented is an SMTP transport over a
607 TCP/IP network (using sockets, including support for IPv6). However, a pipe
608 transport is available, and there are facilities for writing messages to files
609 and pipes, optionally in \*batched SMTP*\ format; these facilities can be used
610 to send messages to some other transport mechanism such as UUCP, provided it
611 can handle domain-style addresses. Batched SMTP input is also catered for.
613 Exim is not designed for storing mail for dial-in hosts. When the volumes of
614 such mail are large, it is better to get the messages `delivered' into files
615 (that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
618 Although Exim does have some facilities for scanning incoming messages, these
619 are not comprehensive enough to do full virus or spam scanning. Such operations
620 are best carried out using additional specialized software packages.
625 .section Run time configuration
626 Exim's run time configuration is held in a single text file that is divided
627 into a number of sections. The entries in this file consist of keywords and
628 values, in the style of Smail 3 configuration files. A default configuration
629 file which is suitable for simple online installations is provided in the
630 distribution, and is described in chapter ~~CHAPdefconfil below.
633 .section Calling interface
634 .index Sendmail compatibility||command line interface
635 Like many MTAs, Exim has adopted the Sendmail command line interface so that it
636 can be a straight replacement for \(/usr/lib/sendmail)\ or
637 \(/usr/sbin/sendmail)\ when sending mail, but you do not need to know anything
638 about Sendmail in order to run Exim. For actions other than sending messages,
639 Sendmail-compatible options also exist, but those that produce output (for
640 example, \-bp-\, which lists the messages on the queue) do so in Exim's own
641 format. There are also some additional options that are compatible with Smail
642 3, and some further options that are new to Exim. Chapter ~~CHAPcommandline
643 documents all Exim's command line options. This information is automatically
644 made into the man page that forms part of the Exim distribution.
646 Control of messages on the queue can be done via certain privileged command
647 line options. There is also an optional monitor program called \*eximon*\, which
648 displays current information in an X window, and which contains a menu
649 interface to Exim's command line administration options.
653 .index terminology definitions
654 .index body of message||definition of
655 The \*body*\ of a message is the actual data that the sender wants to transmit.
656 It is the last part of a message, and is separated from the \*header*\ (see
657 below) by a blank line.
659 .index bounce message||definition of
660 When a message cannot be delivered, it is normally returned to the sender in a
661 delivery failure message. The term \*bounce*\ is commonly used for this action,
662 and the error reports are often called \*bounce messages*\. This is a
663 convenient shorthand for `delivery failure error report'. Such messages have an
664 empty sender address in the message's \*envelope*\ (see below) to ensure that
665 they cannot themselves give rise to further bounce messages.
667 The term \*default*\ appears frequently in this manual. It is used to qualify a
668 value which is used in the absence of any setting in the configuration. It may
669 also qualify an action which is taken unless a configuration setting specifies
672 The term \*defer*\ is used when the delivery of a message to a specific
673 destination cannot immediately take place for some reason (a remote host may be
674 down, or a user's local mailbox may be full). Such deliveries are \*deferred*\
677 The word \*domain*\ is sometimes used to mean all but the first component of a
678 host's name. It is $it{not} used in that sense here, where it normally
679 refers to the part of an email address following the @@ sign.
681 .index envelope, definition of
682 .index sender||definition of
683 A message in transit has an associated \*envelope*\, as well as a header and a
684 body. The envelope contains a sender address (to which bounce messages should
685 be delivered), and any number of recipient addresses. References to the
686 sender or the recipients of a message usually mean the addresses in the
687 envelope. An MTA uses these addresses for delivery, and for returning bounce
688 messages, not the addresses that appear in the header lines.
690 .index message||header, definition of
691 .index header section||definition of
692 The \*header*\ of a message is the first part of a message's text, consisting
693 of a number of lines, each of which has a name such as ::From::, ::To::,
694 ::Subject::, etc. Long header lines can be split over several text lines by
695 indenting the continuations. The header is separated from the body by a blank
698 .index local part||definition of
699 .index domain||definition of
700 The term \*local part*\, which is taken from RFC 2822, is used to refer to that
701 part of an email address that precedes the @@ sign. The part that follows the
702 @@ sign is called the \*domain*\ or \*mail domain*\.
704 .index local delivery||definition of
705 .index remote delivery, definition of
706 The terms \*local delivery*\ and \*remote delivery*\ are used to distinguish
707 delivery to a file or a pipe on the local host from delivery by SMTP over
708 TCP/IP to a remote host.
710 .index return path||definition of
711 \*Return path*\ is another name that is used for the sender address in a
714 .index queue||definition of
715 The term \*queue*\ is used to refer to the set of messages awaiting delivery,
716 because this term is in widespread use in the context of MTAs. However, in
717 Exim's case the reality is more like a pool than a queue, because there is
718 normally no ordering of waiting messages.
720 .index queue runner||definition of
721 The term \*queue runner*\ is used to describe a process that scans the queue
722 and attempts to deliver those messages whose retry times have come. This term
723 is used by other MTAs, and also relates to the command \runq\, but in Exim
724 the waiting messages are normally processed in an unpredictable order.
726 .index spool directory||definition of
727 The term \*spool directory*\ is used for a directory in which Exim keeps the
728 messages on its queue -- that is, those that it is in the process of
729 delivering. This should not be confused with the directory in which local
730 mailboxes are stored, which is called a `spool directory' by some people. In
731 the Exim documentation, `spool' is always used in the first sense.
739 . ============================================================================
740 .chapter Incorporated code
741 .set runningfoot "incorporated code"
742 .index incorporated code
743 .index regular expressions||library
745 A number of pieces of external code are included in the Exim distribution.
747 Regular expressions are supported in the main Exim program and in the Exim
748 monitor using the freely-distributable PCRE library, copyright (c) 2003
749 University of Cambridge. The source is distributed in the directory
750 \(src/pcre)\. However, this is a cut-down version of PCRE. If you want to use
751 the PCRE library in other programs, you should obtain and install the full
752 version from \?ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre?\.
756 .index cdb||acknowledgement
757 Support for the cdb (Constant DataBase) lookup method is provided by code
758 contributed by Nigel Metheringham of Planet Online Ltd. which contains the
759 following statements:
766 Copyright (c) 1998 Nigel Metheringham, Planet Online Ltd
768 This program is free software; you can redistribute it and/or modify it under
769 the terms of the GNU General Public License as published by the Free Software
770 Foundation; either version 2 of the License, or (at your option) any later
773 This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
774 the spec and sample code for cdb can be obtained from
775 \?http://www.pobox.com/@~djb/cdb.html?\. This implementation borrows some code
776 from Dan Bernstein's implementation (which has no license restrictions applied
781 The implementation is completely contained within the code of Exim.
782 It does not link against an external cdb library.
785 .index SPA authentication
787 .index Microsoft Secure Password Authentication
788 Client support for Microsoft's \*Secure Password Authentication*\ is provided
789 by code contributed by Marc Prud'hommeaux. Server support was contributed by
790 Tom Kistner. This includes code taken from the Samba project, which is released
796 .index \*pwcheck*\ daemon
797 .index \*pwauthd*\ daemon
798 Support for calling the Cyrus \*pwcheck*\ and \*saslauthd*\ daemons is provided
799 by code taken from the Cyrus-SASL library and adapted by Alexander S.
800 Sabourenkov. The permission notice appears below, in accordance with the
801 conditions expressed therein.
809 Copyright (c) 2001 Carnegie Mellon University. All rights reserved.
811 Redistribution and use in source and binary forms, with or without
812 modification, are permitted provided that the following conditions
816 .cancelflag $npbracket
817 .flag $npbracket "" "."
820 Redistributions of source code must retain the above copyright
821 notice, this list of conditions and the following disclaimer.
823 Redistributions in binary form must reproduce the above copyright
824 notice, this list of conditions and the following disclaimer in
825 the documentation and/or other materials provided with the
828 The name `Carnegie Mellon University' must not be used to
829 endorse or promote products derived from this software without
830 prior written permission. For permission or any other legal
831 details, please contact
833 Office of Technology Transfer
834 Carnegie Mellon University
836 Pittsburgh, PA 15213-3890
837 (412) 268-4387, fax: (412) 268-7395
838 tech-transfer@@andrew.cmu.edu
841 Redistributions of any form whatsoever must retain the following
845 .indent ~~sys.indent + 3em
847 $it{This product includes software developed by Computing Services
848 at Carnegie Mellon University (\?http://www.cmu.edu/computing/?\).}
853 .cancelflag $npbracket
854 .flag $npbracket "(" ")"
857 CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
858 THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
859 AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
860 FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
861 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
862 AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
863 OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
873 The Exim Monitor program, which is an X-Window application, includes
874 modified versions of the Athena StripChart and TextPop widgets.
875 This code is copyright by DEC and MIT, and their permission notice appears
876 below, in accordance with the conditions expressed therein.
884 Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
885 and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
887 $c All Rights Reserved
889 Permission to use, copy, modify, and distribute this software and its
890 documentation for any purpose and without fee is hereby granted,
891 provided that the above copyright notice appear in all copies and that
892 both that copyright notice and this permission notice appear in
893 supporting documentation, and that the names of Digital or MIT not be
894 used in advertising or publicity pertaining to distribution of the
895 software without specific, written prior permission.
897 DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
898 ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
899 DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
900 ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
901 WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
902 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
915 . ============================================================================
916 .chapter How Exim receives and delivers mail
917 .set runningfoot "receiving & delivering mail"
919 .section Overall philosophy
920 .index design philosophy
921 Exim is designed to work efficiently on systems that are permanently connected
922 to the Internet and are handling a general mix of mail. In such circumstances,
923 most messages can be delivered immediately. Consequently, Exim does not
924 maintain independent queues of messages for specific domains or hosts, though
925 it does try to send several messages in a single SMTP connection after a host
926 has been down, and it also maintains per-host retry information.
929 .section Policy control
930 .index policy control||overview
931 Policy controls are now an important feature of MTAs that are connected to the
932 Internet. Perhaps their most important job is to stop MTAs being abused as
933 `open relays' by misguided individuals who send out vast amounts of unsolicited
934 junk, and want to disguise its source. Exim provides flexible facilities for
935 specifying policy controls on incoming mail:
937 .index ~~ACL||introduction
938 Exim 4 (unlike previous versions of Exim) implements policy controls on
939 incoming SMTP mail by means of \*Access Control Lists*\ (ACLs). Each list is a
940 series of statements that may either grant or deny access. ACLs can be used at
941 several places in the SMTP dialogue while receiving a message. However, the
942 most common places are after each \\RCPT\\ command, and at the very end of the
943 message. The sysadmin can specify conditions for accepting or rejecting
944 individual recipients or the entire message, respectively, at these two points
945 (see chapter ~~CHAPACL). Denial of access results in an SMTP error code.
947 An ACL is also available for locally generated, non-SMTP messages. In this
948 case, the only available actions are to accept or deny the entire message.
950 When a message has been received, either from a remote host or from the local
951 host, but before the final acknowledgement has been sent, a locally supplied C
952 function called \*local@_scan()*\ can be run to inspect the message and decide
953 whether to accept it or not (see chapter ~~CHAPlocalscan). If the message is
954 accepted, the list of recipients can be modified by the function.
956 After a message has been accepted, a further checking mechanism is available in
957 the form of the $it{system filter} (see chapter ~~CHAPsystemfilter). This runs
958 at the start of every delivery process.
961 .section User filters
962 .index filter||introduction
964 In a conventional Exim configuration, users are able to run private filters by
965 setting up appropriate \(.forward)\ files in their home directories. See
966 chapter ~~CHAPredirect (about the \%redirect%\ router) for the configuration
967 needed to support this, and the separate document entitled
969 [(A HREF="filter_toc.html")]
971 \*Exim's interfaces to mail filtering*\
975 for user details. Two different kinds of filtering are available:
977 Sieve filters are written in the standard filtering language that is defined by
980 Exim filters are written in a syntax that is unique to Exim, but which is more
981 powerful than Sieve, which it pre-dates.
983 User filters are run as part of the routing process, described below.
986 .section Message identification
987 .rset SECTmessiden "~~chapter.~~section"
988 .index message||ids, details of format
989 .index format||of message id
995 Every message handled by Exim is given a \*message id*\ which is sixteen
996 characters long. It is divided into three parts, separated by hyphens, for
997 example \"16VDhn-0001bo-D3"\. Each part is a sequence of letters and digits,
998 normally encoding numbers in base 62. However, in the Darwin operating
999 system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
1000 (avoiding the use of lower case letters) is used instead, because the message
1001 id is used to construct file names, and the names of files in those systems are
1004 .index pid (process id)||re-use of
1005 The detail of the contents of the message id have changed as Exim has evolved.
1006 Earlier versions relied on the operating system not re-using a process id (pid)
1007 within one second. On modern operating systems, this assumption can no longer
1008 be made, so the algorithm had to be changed. To retain backward compatibility,
1009 the format of the message id was retained, which is why the following rules are
1012 The first six characters of the message id are the time at which the message
1013 started to be received, to a granularity of one second. That is, this field
1014 contains the number of seconds since the start of the epoch (the normal Unix
1015 way of representing the date and time of day).
1017 After the first hyphen, the next six characters are the id of the process that
1018 received the message.
1020 There are two different possibilities for the final two characters:
1022 .index \localhost@_number\
1023 If \localhost@_number\ is not set, this value is the fractional part of the
1024 time of reception, normally in units of 1/2000 of a second, but for systems
1025 that must use base 36 instead of base 62 (because of case-insensitive file
1026 systems), the units are 1/1000 of a second.
1028 If \localhost@_number\ is set, it is multiplied by 200 (100) and added to
1029 the fractional part of the time, which in this case is in units of 1/200
1030 (1/100) of a second.
1033 After a message has been received, Exim waits for the clock to tick at the
1034 appropriate resolution before proceeding, so that if another message is
1035 received by the same process, or by another process with the same (re-used)
1036 pid, it is guaranteed that the time will be different. In most cases, the clock
1037 will already have ticked while the message was being received.
1039 .section Receiving mail
1040 .index receiving mail
1041 .index message||reception
1042 The only way Exim can receive mail from a remote host is using SMTP over
1043 TCP/IP, in which case the sender and recipient addresses are tranferred using
1044 SMTP commands. However, from a locally running process (such as a user's MUA),
1045 there are several possibilities:
1047 If the process runs Exim with the \-bm-\ option, the message is read
1048 non-interactively (usually via a pipe), with the recipients taken from the
1049 command line, or from the body of the message if \-t-\ is also used.
1051 If the process runs Exim with the \-bS-\ option, the message is also read
1052 non-interactively, but in this case the recipients are listed at the start of
1053 the message in a series of SMTP \\RCPT\\ commands, terminated by a \\DATA\\
1054 command. This is so-called `batch SMTP' format,
1055 but it isn't really SMTP. The SMTP commands are just another way of passing
1056 envelope addresses in a non-interactive submission.
1058 If the process runs Exim with the \-bs-\ option, the message is read
1059 interactively, using the SMTP protocol. A two-way pipe is normally used for
1060 passing data between the local process and the Exim process.
1061 This is `real' SMTP and is handled in the same way as SMTP over TCP/IP. For
1062 example, the ACLs for SMTP commands are used for this form of submission.
1064 A local process may also make a TCP/IP call to the host's loopback address
1065 (127.0.0.1) or any other of its IP addresses. When receiving messages, Exim
1066 does not treat the loopback address specially. It treats all such connections
1067 in the same way as connections from other hosts.
1070 .index message||sender, constructed by Exim
1071 .index sender||constructed by Exim
1072 In the three cases that do not involve TCP/IP, the sender address is
1073 constructed from the login name of the user that called Exim and a default
1074 qualification domain (which can be set by the \qualify@_domain\ configuration
1075 option). For local or batch SMTP, a sender address that is passed using the
1076 SMTP \\MAIL\\ command is ignored. However, the system administrator may allow
1077 certain users (`trusted users') to specify a different sender address
1078 unconditionally, or all users to specify certain forms of different sender
1079 address. The \-f-\ option or the SMTP \\MAIL\\ command is used to specify these
1080 different addresses. See section ~~SECTtrustedadmin for details of trusted
1081 users, and the \untrusted@_set@_sender\ option for a way of allowing untrusted
1082 users to change sender addresses.
1084 Messages received by either of the non-interactive mechanisms are subject to
1085 checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1086 (either over TCP/IP, or interacting with a local process) can be checked by a
1087 number of ACLs that operate at different times during the SMTP session. Either
1088 individual recipients, or the entire message, can be rejected if local policy
1089 requirements are not met. The \*local@_scan()*\ function (see chapter
1090 ~~CHAPlocalscan) is run for all incoming messages.
1092 Exim can be configured not to start a delivery process when a message is
1093 received; this can be unconditional, or depend on the number of incoming SMTP
1094 connections or the system load. In these situations, new messages wait on the
1095 queue until a queue runner process picks them up. However, in standard
1096 configurations under normal conditions, delivery is started as soon as a
1097 message is received.
1102 .section Handling an incoming message
1103 .index spool directory||files that hold a message
1104 .index file||how a message is held
1105 When Exim accepts a message, it writes two files in its spool directory. The
1106 first contains the envelope information, the current status of the message,
1107 and the header lines, and the second contains the body of the message. The
1108 names of the two spool files consist of the message id, followed by $tt{-H} for
1109 the file containing the envelope and header, and $tt{-D} for the data file.
1111 .index spool directory||\(input)\ sub-directory
1112 By default all these message files are held in a single directory called
1113 \(input)\ inside the general Exim spool directory. Some operating systems do
1114 not perform very well if the number of files in a directory gets very large; to
1115 improve performance in such cases, the \split@_spool@_directory\ option can be
1116 used. This causes Exim to split up the input files into 62 sub-directories
1117 whose names are single letters or digits.
1119 The envelope information consists of the address of the message's sender and
1120 the addresses of the recipients. This information is entirely separate from
1121 any addresses contained in the header lines. The status of the message includes
1122 a list of recipients who have already received the message. The format of the
1123 first spool file is described in chapter ~~CHAPspool.
1125 .index rewriting||addresses
1126 Address rewriting that is specified in the rewrite section of the configuration
1127 (see chapter ~~CHAPrewrite) is done once and for all on incoming addresses,
1128 both in the header lines and the envelope, at the time the message is accepted.
1129 If during the course of delivery additional addresses are generated (for
1130 example, via aliasing), these new addresses are rewritten as soon as they are
1131 generated. At the time a message is actually delivered (transported) further
1132 rewriting can take place; because this is a transport option, it can be
1133 different for different forms of delivery. It is also possible to specify the
1134 addition or removal of certain header lines at the time the message is
1135 delivered (see chapters ~~CHAProutergeneric and ~~CHAPtransportgeneric).
1138 .section Life of a message
1139 .index message||life of
1140 .index message||frozen
1141 A message remains in the spool directory until it is completely delivered to
1142 its recipients or to an error address, or until it is deleted by an
1143 administrator or by the user who originally created it. In cases when delivery
1144 cannot proceed -- for example, when a message can neither be delivered to its
1145 recipients nor returned to its sender, the message is marked `frozen' on the
1146 spool, and no more deliveries are attempted.
1148 .index frozen messages||thawing
1149 .index message||thawing frozen
1150 An administrator can `thaw' such messages when the problem has been corrected,
1151 and can also freeze individual messages by hand if necessary. In addition, an
1152 administrator can force a delivery error, causing a bounce message to be sent.
1155 There is an option called \auto@_thaw\, which can be used to cause Exim to
1156 retry frozen messages after a certain time. When this is set, no message will
1157 remain on the queue for ever, because the delivery timeout will eventually be
1158 reached. Delivery failure reports (bounce messages) that reach this timeout are
1160 .index \timeout@_frozen@_after\
1161 There is also an option called \timeout@_frozen@_after\, which discards frozen
1162 messages after a certain time.
1164 .index message||log file for
1165 .index log||file for each message
1166 While Exim is working on a message, it writes information about each delivery
1167 attempt to the main log file. This includes successful, unsuccessful, and
1168 delayed deliveries for each recipient (see chapter ~~CHAPlog). The log lines
1169 are also written to a separate $it{message log} file for each message. These
1170 logs are solely for the benefit of the administrator, and are normally deleted
1171 along with the spool files when processing of a message is complete.
1172 The use of individual message logs can be disabled by setting
1173 \no@_message@_logs\; this might give an improvement in performance on very
1177 .index file||journal
1178 All the information Exim itself needs to set up a delivery is kept in the first
1179 spool file, along with the header lines. When a successful delivery occurs, the
1180 address is immediately written at the end of a journal file, whose name is the
1181 message id followed by $tt{-J}. At the end of a delivery run, if there are some
1182 addresses left to be tried again later, the first spool file (the $tt{-H} file)
1183 is updated to indicate which these are, and the journal file is then deleted.
1184 Updating the spool file is done by writing a new file and renaming it, to
1185 minimize the possibility of data loss.
1187 Should the system or the program crash after a successful delivery but before
1188 the spool file has been updated, the journal is left lying around. The next
1189 time Exim attempts to deliver the message, it reads the journal file and
1190 updates the spool file before proceeding. This minimizes the chances of double
1191 deliveries caused by crashes.
1194 .section Processing an address for delivery
1195 .rset SECTprocaddress "~~chapter.~~section"
1196 .index drivers||definition of
1197 .index router||definition of
1198 .index transport||definition of
1199 The main delivery processing elements of Exim are called $it{routers} and
1200 $it{transports}, and collectively these are known as $it{drivers}. Code for a
1201 number of them is provided in the source distribution, and compile-time options
1202 specify which ones are included in the binary. Run time options specify which
1203 ones are actually used for delivering messages.
1205 .index drivers||instance definition
1206 Each driver that is specified in the run time configuration is an \*instance*\
1207 of that particular driver type. Multiple instances are allowed; for example,
1208 you can set up several different \%smtp%\ transports, each with different
1209 option values that might specify different ports or different timeouts. Each
1210 instance has its own identifying name. In what follows we will normally use the
1211 instance name when discussing one particular instance (that is, one specific
1212 configuration of the driver), and the generic driver name when discussing
1213 the driver's features in general.
1215 A $it{router} is a driver that operates on an address, either determining how
1216 its delivery should happen, by routing it to a specific transport, or
1217 converting the address into one or more new addresses (for example, via an
1218 alias file). A router may also explicitly choose to fail an address, causing it
1221 A $it{transport} is a driver that transmits a copy of the message from Exim's
1222 spool to some destination. There are two kinds of transport: for a $it{local}
1223 transport, the destination is a file or a pipe on the local host, whereas for a
1224 $it{remote} transport the destination is some other host. A message is passed
1225 to a specific transport as a result of successful routing. If a message has
1226 several recipients, it may be passed to a number of different transports.
1228 .index preconditions||definition of
1229 An address is processed by passing it to each configured router instance in
1230 turn, subject to certain preconditions, until a router accepts the address or
1231 specifies that it should be bounced. We will describe this process in more
1232 detail shortly. As a simple example, the diagram below illustrates how each
1233 recipient address in a message is processed in a small configuration of three
1234 routers that are configured in various ways.
1237 .figure "Routing an address" rm
1239 .call aspic -sgcal -nv
1240 centre ~~sys.linelength;
1243 ibox depth 14 "address";
1246 A: box width 100 "first router" "conditions ok?";
1248 C: box width 100 "run" "first router";
1250 D: ibox depth 20 "address bounces";
1252 arc clockwise from right of C "accept";
1254 ibox "queue for" "transport";
1256 arrow down from A align bottom of D plus (0,-20) "no"(-6,20)/r;
1257 E: box width 100 "second router" "conditions ok?";
1259 F: box width 100 "run" "second router";
1260 line right 100 "redirect";
1261 line up align middle of B;
1262 arrow left to middle of B "new addresses";
1264 line down 20 from bottom left of F plus (30,0);
1265 arrow left align centre of E "decline";
1267 line down 20 from bottom right of F plus (-30,0);
1269 ibox width 64 "address" "bounces";
1271 arrow down 64 from E "no"(-6,20)/r;
1272 G: box width 100 "third router" "conditions ok?";
1274 H: box width 100 "run" "third router";
1275 arc clockwise from right of H "accept";
1277 ibox "queue for" "transport";
1279 line down 20 from bottom of H;
1280 arrow left align centre of G "decline";
1281 arrow down 64 from G "no"(-6,20)/r;
1283 ibox "no more routers" "address bounces";
1291 |<------------- new addresses -----------------------------
1293 ----------------- ----------------- |
1294 | first router |----- yes ----->| run |--- accept |
1295 | conditions ok?| | first router | | |
1296 ----------------- ----------------- | |
1298 no | fail | queue for |
1303 ----------------- ----------------- |
1304 | second router |----- yes ----->| run |----redirect ----
1305 | conditions ok?| | second router |
1306 ----------------- -----------------
1309 |<-------- decline ----------- --- fail ---> address
1312 ----------------- -----------------
1313 | third router |----- yes ----->| run |--- accept
1314 | conditions ok?| | third router | |
1315 ----------------- ----------------- |
1318 |<-------- decline --------------- transport
1325 [(img src="routing.gif" alt="Routing an address")][(br)]
1327 To make this a more concrete example, we'll describe it in terms of some actual
1328 routers, but remember, this is only an example. You can configure Exim's
1329 routers in many different ways, and there may be any number of routers in a
1332 The first router that is specified in a configuration is often one that handles
1333 addresses in domains that are not recognized specially by the local host. These
1334 are typically addresses for arbitrary domains on the Internet. A precondition
1335 is set up which looks for the special domains known to the host (for example,
1336 its own domain name), and the router is run for addresses that do $it{not}
1337 match. Typically, this is a router that looks up domains in the DNS in order to
1338 find the hosts to which this address routes. If it succeeds, the address is
1339 queued for a suitable SMTP transport; if it does not succeed, the router is
1340 configured to fail the address.
1342 The example pictured could be a configuration of this type. The second and
1343 third routers can only be run for addresses for which the preconditions for
1344 the first router are not met. If one of these preconditions checks the
1345 domain, the second and third routers are run only for domains that are somehow
1346 special to the local host.
1348 The second router does redirection -- also known as aliasing and forwarding.
1349 When it generates one or more new addresses from the original, each of them is
1350 routed independently from the start. Otherwise, the router may cause an address
1351 to fail, or it may simply decline to handle the address, in which case the
1352 address is passed to the next router.
1354 The final router in many configurations is one that checks to see if the
1355 address belongs to a local mailbox. The precondition may involve a check to
1356 see if the local part is the name of a login account, or it may look up the
1357 local part in a file or a database. If its preconditions are not met, or if
1358 the router declines, we have reached the end of the routers. When this happens,
1359 the address is bounced.
1362 .section Processing an address for verification
1363 .index router||for verification
1364 .index verifying||address, overview
1365 As well as being used to decide how to deliver to an address, Exim's routers
1366 are also used for \*address verification*\. Verification can be requested as
1367 one of the checks to be performed in an ACL for incoming messages, on both
1368 sender and recipient addresses, and it can be tested using the \-bv-\ and
1369 \-bvs-\ command line options.
1371 When an address is being verified, the routers are run in `verify mode'. This
1372 does not affect the way the routers work, but it is a state that can be
1373 detected. By this means, a router can be skipped or made to behave differently
1374 when verifying. A common example is a configuration in which the first router
1375 sends all messages to a message-scanning program, unless they have been
1376 previously scanned. Thus, the first router accepts all addresses without any
1377 checking, making it useless for verifying. Normally, the \no@_verify\ option
1378 would be set for such a router, causing it to be skipped in verify mode.
1382 .section Running an individual router
1383 .rset SECTrunindrou "~~chapter.~~section"
1384 .index router||running details
1385 .index preconditions||checking
1386 .index router||result of running
1387 As explained in the example above, a number of preconditions are checked before
1388 running a router. If any are not met, the router is skipped, and the address is
1389 passed to the next router. When all the preconditions on a router $it{are} met,
1390 the router is run. What happens next depends on the outcome, which is one of
1393 \*accept*\: The router accepts the address, and either queues it for a
1394 transport, or generates one or more `child' addresses. Processing the original
1396 .index \unseen\ option
1397 unless the \unseen\ option is set on the router. This option
1398 can be used to set up multiple deliveries with different routing (for example,
1399 for keeping archive copies of messages). When \unseen\ is set, the address is
1400 passed to the next router. Normally, however, an \*accept*\ return marks the
1403 .index case of local parts
1404 .index address||duplicate, discarding
1405 If child addresses are generated, Exim checks to see whether they are
1406 duplicates of any existing recipient addresses. During this check, local parts
1407 are treated as case-sensitive. Duplicate addresses are discarded. Each of the
1408 remaining child addresses is then processed independently, starting with the
1409 first router by default. It is possible to change this by setting the
1410 \redirect@_router\ option to specify which router to start at for child
1411 addresses. Unlike \pass@_router\ (see below) the router specified by
1412 \redirect@_router\ may be anywhere in the router configuration.
1414 \*pass*\: The router recognizes the address, but cannot handle it itself. It
1415 requests that the address be passed to another router. By default the address
1416 is passed to the next router, but this can be changed by setting the
1417 \pass@_router\ option. However, (unlike \redirect@_router\) the named router
1418 must be below the current router (to avoid loops).
1420 \*decline*\: The router declines to accept the address because it does not
1421 recognize it at all. By default, the address is passed to the next router, but
1422 this can be prevented by setting the \no@_more\ option. When \no@_more\ is set,
1423 all the remaining routers are skipped.
1425 \*fail*\: The router determines that the address should fail, and queues it for
1426 the generation of a bounce message. There is no further processing of the
1427 original address unless \unseen\ is set on the router.
1429 \*defer*\: The router cannot handle the address at the present time. (A database
1430 may be offline, or a DNS lookup may have timed out.) No further processing of
1431 the address happens in this delivery attempt. It is tried again next time the
1432 message is considered for delivery.
1434 \*error*\: There is some error in the router (for example, a syntax error in
1435 its configuration). The action is as for defer.
1437 If an address reaches the end of the routers without having been accepted by
1438 any of them, it is bounced as unrouteable.
1439 The default error message in this situation is `unrouteable address', but you
1440 can set your own message by making use of the \cannot@_route@_message\ option.
1441 This can be set for any router; the value from the last router that `saw'
1442 the address is used.
1444 Sometimes while routing you want to fail a delivery when some conditions are
1445 met but others are not, instead of passing the address on for further routing.
1446 You can do this by having a second router that explicitly fails the delivery
1447 when the relevant conditions are met. The \%redirect%\ router has a `fail'
1448 facility for this purpose.
1452 .section Router preconditions
1453 .rset SECTrouprecon "~~chapter.~~section"
1454 .index router||preconditions, order of processing
1455 .index preconditions||order of processing
1456 The preconditions that are tested for each router are listed below, in the
1457 order in which they are tested. The individual configuration options are
1458 described in more detail in chapter ~~CHAProutergeneric.
1460 The \local@_part@_prefix\ and \local@_part@_suffix\ options can specify that
1461 the local parts handled by the router may or must have certain prefixes and/or
1462 suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1463 skipped. These conditions are tested first. When an affix is present, it is
1464 removed from the local part before further processing, including the evaluation
1465 of any other conditions.
1467 Routers can be designated for use only when not verifying an address, that is,
1468 only when routing it for delivery (or testing its delivery routing). If the
1469 \verify\ option is set false, the router is skipped when Exim is verifying an
1471 Setting the \verify\ option actually sets two options, \verify@_sender\ and
1472 \verify@_recipient\, which independently control the use of the router for
1473 sender and recipient verification. You can set these options directly if
1474 you want a router to be used for only one type of verification.
1476 If the \address@_test\ option is set false, the router is skipped when Exim is
1477 run with the \-bt-\ option to test an address routing. This can be helpful when
1478 the first router sends all new messages to a scanner of some sort; it makes it
1479 possible to use \-bt-\ to test subsequent delivery routing without having to
1480 simulate the effect of the scanner.
1482 Routers can be designated for use only when verifying an address, as
1483 opposed to routing it for delivery. The \verify@_only\ option controls this.
1485 Certain routers can be explicitly skipped when running the routers to check an
1486 address given in the SMTP \\EXPN\\ command (see the \expn\ option).
1488 If the \domains\ option is set, the domain of the address must be in the set of
1489 domains that it defines.
1491 If the \local@_parts\ option is set, the local part of the address must be in
1492 the set of local parts that it defines. If \local@_part@_prefix\ or
1493 \local@_part@_suffix\ is in use, the prefix or suffix is removed from the local
1494 part before this check. If you want to do precondition tests on local parts
1495 that include affixes, you can do so by using a \condition\ option (see below)
1496 that uses the variables \$local@_part$\, \$local@_part@_prefix$\, and
1497 \$local@_part@_suffix$\ as necessary.
1499 If the \check@_local@_user\ option is set, the local part must be the name of
1500 an account on the local host.
1501 If this check succeeds, the uid and gid of the local user are placed in
1502 \$local@_user@_uid$\ and \$local@_user@_gid$\; these values can be used in the
1503 remaining preconditions.
1505 If the \router@_home@_directory\ option is set, it is expanded at this point,
1506 because it overrides the value of \$home$\. If this expansion were left till
1507 later, the value of \$home$\ as set by \check@_local@_user\ would be used in
1508 subsequent tests. Having two different values of \$home$\ in the same router
1509 could lead to confusion.
1511 If the \senders\ option is set, the envelope sender address must be in the set
1512 of addresses that it defines.
1514 If the \require@_files\ option is set, the existence or non-existence of
1515 specified files is tested.
1517 .index customizing||precondition
1518 If the \condition\ option is set, it is evaluated and tested. This option uses
1519 an expanded string to allow you to set up your own custom preconditions.
1520 Expanded strings are described in chapter ~~CHAPexpand.
1523 Note that \require@_files\ comes near the end of the list, so you cannot use it
1524 to check for the existence of a file in which to lookup up a domain, local
1525 part, or sender. However, as these options are all expanded, you can use the
1526 \exists\ expansion condition to make such tests within each condition. The
1527 \require@_files\ option is intended for checking files that the router may be
1528 going to use internally, or which are needed by a specific transport (for
1529 example, \(.procmailrc)\).
1532 .section Delivery in detail
1533 .index delivery||in detail
1534 When a message is to be delivered, the sequence of events is as follows:
1536 If a system-wide filter file is specified, the message is passed to it. The
1537 filter may add recipients to the message, replace the recipients, discard the
1538 message, cause a new message to be generated, or cause the message delivery to
1539 fail. The format of the system filter file is the same as for Exim user filter
1540 files, described in the separate document entitled
1542 [(A HREF="filter.html")]
1544 \*Exim's interfaces to mail filtering*\.
1548 .index Sieve filter||not available for system filter
1549 (\**Note**\: Sieve cannot be used for system filter files.)
1550 Some additional features are available in system filters -- see chapter
1551 ~~CHAPsystemfilter for details. Note that a message is passed to the system
1552 filter only once per delivery attempt, however many recipients it has. However,
1553 if there are several delivery attempts because one or more addresses could not
1554 be immediately delivered, the system filter is run each time. The filter
1555 condition \first@_delivery\ can be used to detect the first run of the system
1558 Each recipient address is offered to each configured router in turn, subject to
1559 its preconditions, until one is able to handle it. If no router can handle
1560 the address, that is, if they all decline, the address is failed. Because
1561 routers can be targeted at particular domains, several locally handled domains
1562 can be processed entirely independently of each other.
1564 .index routing||loops in
1565 .index loop||while routing
1566 A router that accepts an address may set up a local or a remote transport for
1567 it. However, the transport is not run at this time. Instead, the address is
1568 placed on a list for the particular transport, to be run later. Alternatively,
1569 the router may generate one or more new addresses (typically from alias,
1570 forward, or filter files). New addresses are fed back into this process from
1571 the top, but in order to avoid loops, a router ignores any address which has an
1572 identically-named ancestor that was processed by itself.
1574 When all the routing has been done, addresses that have been successfully
1575 handled are passed to their assigned transports. When local transports are
1576 doing real local deliveries, they handle only one address at a time, but if a
1577 local transport is being used as a pseudo-remote transport (for example, to
1578 collect batched SMTP messages for transmission by some other means) multiple
1579 addresses can be handled. Remote transports can always handle more than one
1580 address at a time, but can be configured not to do so, or to restrict multiple
1581 addresses to the same domain.
1583 Each local delivery to a file or a pipe runs in a separate process under a
1584 non-privileged uid, and these deliveries are run one at a time. Remote
1585 deliveries also run in separate processes, normally under a uid that is private
1586 to Exim (`the Exim user'), but in this case, several remote deliveries can be
1587 run in parallel. The maximum number of simultaneous remote deliveries for any
1588 one message is set by the \remote@_max@_parallel\ option.
1589 The order in which deliveries are done is not defined, except that all local
1590 deliveries happen before any remote deliveries.
1593 When it encounters a local delivery during a queue run, Exim checks its retry
1594 database to see if there has been a previous temporary delivery failure for the
1595 address before running the local transport. If there was a previous failure,
1596 Exim does not attempt a new delivery until the retry time for the address is
1597 reached. However, this happens only for delivery attempts that are part of a
1598 queue run. Local deliveries are always attempted when delivery immediately
1599 follows message reception, even if retry times are set for them. This makes for
1600 better behaviour if one particular message is causing problems (for example,
1601 causing quota overflow, or provoking an error in a filter file).
1603 .index delivery||retry in remote transports
1604 Remote transports do their own retry handling, since an address may be
1605 deliverable to one of a number of hosts, each of which may have a different
1606 retry time. If there have been previous temporary failures and no host has
1607 reached its retry time, no delivery is attempted, whether in a queue run or
1608 not. See chapter ~~CHAPretry for details of retry strategies.
1610 If there were any permanent errors, a bounce message is returned to an
1611 appropriate address (the sender in the common case), with details of the error
1612 for each failing address. Exim can be configured to send copies of bounce
1613 messages to other addresses.
1615 .index delivery||deferral
1616 If one or more addresses suffered a temporary failure, the message is left on
1617 the queue, to be tried again later. Delivery of these addresses is said to be
1620 When all the recipient addresses have either been delivered or bounced,
1621 handling of the message is complete. The spool files and message log are
1622 deleted, though the message log can optionally be preserved if required.
1626 .section Retry mechanism
1627 .index delivery||retry mechanism
1628 .index retry||description of mechanism
1630 Exim's mechanism for retrying messages that fail to get delivered at the first
1631 attempt is the queue runner process. You must either run an Exim daemon that
1632 uses the \-q-\ option with a time interval to start queue runners at regular
1633 intervals, or use some other means (such as \*cron*\) to start them. If you do
1634 not arrange for queue runners to be run, messages that fail temporarily at the
1635 first attempt will remain on your queue for ever. A queue runner process works
1636 it way through the queue, one message at a time, trying each delivery that has
1637 passed its retry time.
1638 You can run several queue runners at once.
1640 Exim uses a set of configured rules to determine when next to retry the failing
1641 address (see chapter ~~CHAPretry). These rules also specify when Exim should
1642 give up trying to deliver to the address, at which point it generates a bounce
1643 message. If no retry rules are set for a particular host, address, and error
1644 combination, no retries are attempted, and temporary errors are treated as
1648 .section Temporary delivery failure
1649 .index delivery||temporary failure
1650 There are many reasons why a message may not be immediately deliverable to a
1651 particular address. Failure to connect to a remote machine (because it, or the
1652 connection to it, is down) is one of the most common. Temporary failures may be
1653 detected during routing as well as during the transport stage of delivery.
1654 Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1655 is on a file system where the user is over quota. Exim can be configured to
1656 impose its own quotas on local mailboxes; where system quotas are set they will
1659 If a host is unreachable for a period of time, a number of messages may be
1660 waiting for it by the time it recovers, and sending them in a single SMTP
1661 connection is clearly beneficial. Whenever a delivery to a remote host is
1663 .index hints database
1664 Exim makes a note in its hints database, and whenever a successful
1665 SMTP delivery has happened, it looks to see if any other messages are waiting
1666 for the same host. If any are found, they are sent over the same SMTP
1667 connection, subject to a configuration limit as to the maximum number in any
1672 .section Permanent delivery failure
1673 .index delivery||permanent failure
1674 .index bounce message||when generated
1675 When a message cannot be delivered to some or all of its intended recipients, a
1676 bounce message is generated. Temporary delivery failures turn into permanent
1677 errors when their timeout expires. All the addresses that fail in a given
1678 delivery attempt are listed in a single message. If the original message has
1679 many recipients, it is possible for some addresses to fail in one delivery
1680 attempt and others to fail subsequently, giving rise to more than one bounce
1681 message. The wording of bounce messages can be customized by the administrator.
1682 See chapter ~~CHAPemsgcust for details.
1684 .index ::X-Failed-Recipients:: header line
1685 Bounce messages contain an ::X-Failed-Recipients:: header line that lists the
1686 failed addresses, for the benefit of programs that try to analyse such messages
1689 .index bounce message||recipient of
1690 A bounce message is normally sent to the sender of the original message, as
1691 obtained from the message's envelope. For incoming SMTP messages, this is the
1692 address given in the \\MAIL\\ command. However, when an address is
1693 expanded via a forward or alias file, an alternative address can be specified
1694 for delivery failures of the generated addresses. For a mailing list expansion
1695 (see section ~~SECTmailinglists) it is common to direct bounce messages to the
1696 manager of the list.
1700 .section Failures to deliver bounce messages
1701 .index bounce message||failure to deliver
1702 If a bounce message (either locally generated or received from a remote host)
1703 itself suffers a permanent delivery failure, the message is left on the queue,
1704 but it is frozen, awaiting the attention of an administrator. There are options
1705 which can be used to make Exim discard such failed messages, or to keep them
1706 for only a short time (see \timeout@_frozen@_after\ and
1707 \ignore@_bounce@_errors@_after\).
1715 . ============================================================================
1716 .chapter Building and installing Exim
1717 .set runningfoot "building/installing"
1719 .index building Exim
1721 Exim is distributed as a gzipped or bzipped tar file which, when upacked,
1722 creates a directory with the name of the current release (for example,
1723 \(exim-~~version)\) into which the following files are placed:
1725 .if !~~sys.fancy && ~~sgcal
1730 \(ACKNOWLEDGMENTS)\ $t contains some acknowledgments
1732 \(CHANGES)\ $t contains a reference to where changes are documented
1733 \(LICENCE)\ $t the GNU General Public Licence
1734 \(Makefile)\ $t top-level make file
1735 \(NOTICE)\ $t conditions for the use of Exim
1736 \(README)\ $t list of files, directories and simple build instructions
1738 Other files whose names begin with \(README)\ may also be present. The
1739 following subdirectories are created:
1741 .if !~~sys.fancy && ~~sgcal
1746 \(Local)\ $t an empty directory for local configuration files
1747 \(OS)\ $t OS-specific files
1748 \(doc)\ $t documentation files
1749 \(exim@_monitor)\$t source files for the Exim monitor
1750 \(scripts)\ $t scripts used in the build process
1751 \(src)\ $t remaining source files
1752 \(util)\ $t independent utilities
1754 The main utility programs are contained in the \(src)\ directory, and are built
1755 with the Exim binary. The \(util)\ directory contains a few optional scripts
1756 that may be useful to some sites.
1758 .section Multiple machine architectures and operating systems
1759 .index building Exim||multiple OS/architectures
1760 The building process for Exim is arranged to make it easy to build binaries for
1761 a number of different architectures and operating systems from the same set of
1762 source files. Compilation does not take place in the \(src)\ directory. Instead,
1763 a \*build directory*\ is created for each architecture and operating system.
1764 .index symbolic link||to build directory
1765 Symbolic links to the sources are installed in this directory, which is where
1766 the actual building takes place.
1768 In most cases, Exim can discover the machine architecture and operating system
1769 for itself, but the defaults can be overridden if necessary.
1771 .section DBM libraries
1772 .rset SECTdb "~~chapter.~~section"
1773 .index DBM||libraries, discussion of
1774 .index hints database||DBM files used for
1775 Even if you do not use any DBM files in your configuration, Exim still needs a
1776 DBM library in order to operate, because it uses indexed files for its hints
1777 databases. Unfortunately, there are a number of DBM libraries in existence, and
1778 different operating systems often have different ones installed.
1780 .index Solaris||DBM library for
1781 .index IRIX, DBM library for
1782 .index BSD, DBM library for
1783 .index Linux, DBM library for
1784 If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1785 Linux distribution, the DBM configuration should happen automatically, and you
1786 may be able to ignore this section. Otherwise, you may have to learn more than
1787 you would like about DBM libraries from what follows.
1789 .index \*ndbm*\ DBM library
1790 Licensed versions of Unix normally contain a library of DBM functions operating
1791 via the \*ndbm*\ interface, and this is what Exim expects by default. Free
1792 versions of Unix seem to vary in what they contain as standard. In particular,
1793 some early versions of Linux have no default DBM library, and different
1794 distributors have chosen to bundle different libraries with their packaged
1795 versions. However, the more recent releases seem to have standardised on the
1796 Berkeley DB library.
1798 Different DBM libraries have different conventions for naming the files they
1799 use. When a program opens a file called \(dbmfile)\, there are four
1802 A traditional \*ndbm*\ implementation, such as that supplied as part of
1803 Solaris, operates on two files called \(dbmfile.dir)\ and \(dbmfile.pag)\.
1805 .index \*gdbm*\ DBM library
1806 The GNU library, \*gdbm*\, operates on a single file. If used via its \*ndbm*\
1807 compatibility interface it makes two different hard links to it with names
1808 \(dbmfile.dir)\ and \(dbmfile.pag)\, but if used via its native interface, the
1809 file name is used unmodified.
1811 .index Berkeley DB library
1812 The Berkeley DB package, if called via its \*ndbm*\ compatibility interface,
1813 operates on a single file called \(dbmfile.db)\, but otherwise looks to the
1814 programmer exactly the same as the traditional \*ndbm*\ implementation.
1816 If the Berkeley package is used in its native mode, it operates on a single
1817 file called \(dbmfile)\; the programmer's interface is somewhat different to
1818 the traditional \*ndbm*\ interface.
1820 To complicate things further, there are several very different versions of the
1821 Berkeley DB package. Version 1.85 was stable for a very long time, releases
1822 2.$it{x} and 3.$it{x} were current for a while, but the latest versions are now
1823 numbered 4.$it{x}. Maintenance of some of the earlier releases has ceased. All
1824 versions of Berkeley DB can be obtained from
1826 \?http://www.sleepycat.com/?\
1829 .index \*tdb*\ DBM library
1830 Yet another DBM library, called \*tdb*\, has become available from
1832 \?http://download.sourceforge.net/tdb?\
1834 It has its own interface, and also operates on a single file.
1837 .index DBM||libraries, configuration for building
1838 Exim and its utilities can be compiled to use any of these interfaces. In order
1839 to use any version of the Berkeley DB package in native mode, you must set
1840 \\USE@_DB\\ in an appropriate configuration file (typically
1841 \(Local/Makefile)\). For example:
1845 Similarly, for gdbm you set \\USE@_GDBM\\, and for tdb you set \\USE@_TDB\\. An
1846 error is diagnosed if you set more than one of these.
1848 At the lowest level, the build-time configuration sets none of these options,
1849 thereby assuming an interface of type (1). However, some operating system
1850 configuration files (for example, those for the BSD operating systems and
1851 Linux) assume type (4) by setting \\USE@_DB\\ as their default, and the
1852 configuration files for Cygwin set \\USE@_GDBM\\. Anything you set in
1853 \(Local/Makefile)\, however, overrides these system defaults.
1855 As well as setting \\USE@_DB\\, \\USE@_GDBM\\, or \\USE@_TDB\\, it may also be
1856 necessary to set \\DBMLIB\\, to cause inclusion of the appropriate library, as
1857 in one of these lines:
1862 Settings like that will work if the DBM library is installed in the standard
1863 place. Sometimes it is not, and the library's header file may also not be in
1864 the default path. You may need to set \\INCLUDE\\ to specify where the header
1865 file is, and to specify the path to the library more fully in \\DBMLIB\\, as in
1868 INCLUDE=-I/usr/local/include/db-4.1
1869 DBMLIB=/usr/local/lib/db-4.1/libdb.a
1872 There is further detailed discussion about the various DBM libraries in the
1873 file \(doc/dbm.discuss.txt)\ in the Exim distribution.
1876 .section Pre-building configuration
1877 .index building Exim||pre-building configuration
1878 .index configuration for building Exim
1879 .index \(Local/Makefile)\
1880 .index \(src/EDITME)\
1881 Before building Exim, a local configuration file that specifies options
1882 independent of any operating system has to be created with the name
1883 \(Local/Makefile)\. A template for this file is supplied as the file
1884 \(src/EDITME)\, and it contains full descriptions of all the option settings
1885 therein. These descriptions are therefore not repeated here. If you are
1886 building Exim for the first time, the simplest thing to do is to copy
1887 \(src/EDITME)\ to \(Local/Makefile)\, then read it and edit it appropriately.
1889 There are three settings that you must supply, because Exim will not build
1890 without them. They are the location of the run time configuration file
1891 (\\CONFIGURE@_FILE\\), the directory in which Exim binaries will be installed
1892 (\\BIN@_DIRECTORY\\), and the identity of the Exim user (\\EXIM@_USER\\ and
1893 maybe \\EXIM@_GROUP\\ as well). The value of \\CONFIGURE@_FILE\\ can in fact be
1894 a colon-separated list of file names; Exim uses the first of them that exists.
1896 There are a few other parameters that can be specified either at build time or
1897 at run time, to enable the same binary to be used on a number of different
1898 machines. However, if the locations of Exim's spool directory and log file
1899 directory (if not within the spool directory) are fixed, it is recommended that
1900 you specify them in \(Local/Makefile)\ instead of at run time, so that errors
1901 detected early in Exim's execution (such as a malformed configuration file) can
1904 .index \(Local/eximon.conf)\
1905 .index \(exim@_monitor/EDITME)\
1906 If you are going to build the Exim monitor, a similar configuration process is
1907 required. The file \(exim@_monitor/EDITME)\ must be edited appropriately for
1908 your installation and saved under the name \(Local/eximon.conf)\. If you are
1909 happy with the default settings described in \(exim@_monitor/EDITME)\,
1910 \(Local/eximon.conf)\ can be empty, but it must exist.
1912 This is all the configuration that is needed in straightforward cases for known
1913 operating systems. However, the building process is set up so that it is easy
1914 to override options that are set by default or by operating-system-specific
1915 configuration files, for example to change the name of the C compiler, which
1916 defaults to \gcc\. See section ~~SECToverride below for details of how to do
1920 .section Support for iconv()
1921 .index \*iconv()*\ support
1922 The contents of header lines in messages may be encoded according to the rules
1923 described RFC 2047. This makes it possible to transmit characters that are not
1924 in the ASCII character set, and to label them as being in a particular
1925 character set. When Exim is inspecting header lines by means of the \@$h@_\
1926 mechanism, it decodes them, and translates them into a specified character set
1927 (default ISO-8859-1). The translation is possible only if the operating system
1928 supports the \*iconv()*\ function.
1930 However, some of the operating systems that supply \*iconv()*\ do not support
1931 very many conversions. The GNU \libiconv\ library (available from
1932 \?http:/@/www.gnu.org/software/libiconv/?\) can be installed on such systems to
1933 remedy this deficiency, as well as on systems that do not supply \*iconv()*\ at
1934 all. After installing \libiconv\, you should add
1938 to your \(Local/Makefile)\ and rebuild Exim.
1941 .section Including TLS/SSL encryption support
1942 .rset SECTinctlsssl "~~chapter.~~section"
1943 .index TLS||including support for TLS
1944 .index encryption||including support for
1945 .index \\SUPPORT@_TLS\\
1946 .index OpenSSL||building Exim with
1947 .index GnuTLS||building Exim with
1948 Exim can be built to support encrypted SMTP connections, using the \\STARTTLS\\
1949 command as per RFC 2487. It can also support legacy clients that expect to
1950 start a TLS session immediately on connection to a non-standard port (see the
1951 \-tls-on-connect-\ command line option).
1953 If you want to build Exim with TLS support, you must first install either the
1954 OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1957 If OpenSSL is installed, you should set
1960 TLS_LIBS=-lssl -lcrypto
1962 in \(Local/Makefile)\. You may also need to specify the locations of the
1963 OpenSSL library and include files. For example:
1966 TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1967 TLS_INCLUDE=-I/usr/local/openssl/include/
1970 If GnuTLS is installed, you should set
1971 .index \\USE@_GNUTLS\\
1975 TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1977 in \(Local/Makefile)\, and again you may need to specify the locations of the
1978 library and include files. For example:
1982 TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1983 TLS_INCLUDE=-I/usr/gnu/include
1985 You do not need to set \\TLS@_INCLUDE\\ if the relevant directory is already
1986 specified in \\INCLUDE\\. Details of how to configure Exim to make use of TLS
1987 are given in chapter ~~CHAPTLS.
1991 .section Use of tcpwrappers
1992 .index tcpwrappers, building Exim to support
1993 .index \\USE@_TCP@_WRAPPERS\\
1994 Exim can be linked with the \*tcpwrappers*\ library in order to check incoming
1995 SMTP calls using the \*tcpwrappers*\ control files. This may be a convenient
1996 alternative to Exim's own checking facilities for installations that are
1997 already making use of \*tcpwrappers*\ for other purposes. To do this, you should
1998 set \\USE@_TCP@_WRAPPERS\\ in \(Local/Makefile)\, arrange for the file
1999 \(tcpd.h)\ to be available at compile time, and also ensure that the library
2000 \(libwrap.a)\ is available at link time, typically by including \-lwrap-\ in
2001 \\EXTRALIBS@_EXIM\\. For example, if \*tcpwrappers*\ is installed in
2002 \(/usr/local)\, you might have
2004 USE@_TCP@_WRAPPERS=yes
2005 CFLAGS=-O -I/usr/local/include
2007 EXTRALIBS@_EXIM=-L/usr/local/lib -lwrap
2009 in \(Local/Makefile)\. The name to use in the \*tcpwrappers*\ control files is
2010 `exim'. For example, the line
2012 exim : LOCAL 192.168.1. .friendly.domain.example
2014 in your \(/etc/hosts.allow)\ file allows connections from the local host, from
2015 the subnet 192.168.1.0/24, and from all hosts in \*friendly.domain.example*\.
2016 All other connections are denied. Consult the \*tcpwrappers*\ documentation for
2020 .section Including support for IPv6
2021 .index IPv6||including support for
2022 Exim contains code for use on systems that have IPv6 support. Setting
2023 \\HAVE@_IPV6=YES\\ in \(Local/Makefile)\ causes the IPv6 code to be included;
2024 it may also be necessary to set \\IPV6@_INCLUDE\\ and \\IPV6@_LIBS\\ on systems
2025 where the IPv6 support is not fully integrated into the normal include and
2028 IPv6 is still changing rapidly. Two different types of DNS record for handling
2029 IPv6 addresses have been defined. AAAA records are already in use, and are
2030 currently seen as the `mainstream', but another record type called A6 is being
2031 argued about. Its status is currently `experimental'. Exim has support for A6
2032 records, but this is included only if you set \\SUPPORT@_A6=YES\\ in
2036 .section The building process
2037 .index build directory
2038 Once \(Local/Makefile)\ (and \(Local/eximon.conf)\, if required) have been
2039 created, run \*make*\ at the top level. It determines the architecture and
2040 operating system types, and creates a build directory if one does not exist.
2041 For example, on a Sun system running Solaris 8, the directory
2042 \(build-SunOS5-5.8-sparc)\ is created.
2043 .index symbolic link||to source files
2044 Symbolic links to relevant source files are installed in the build directory.
2046 \**Warning**\: The \-j-\ (parallel) flag must not be used with \*make*\; the
2047 building process fails if it is set.
2049 If this is the first time \*make*\ has been run, it calls a script that builds
2050 a make file inside the build directory, using the configuration files from the
2051 \(Local)\ directory. The new make file is then passed to another instance of
2052 \*make*\. This does the real work, building a number of utility scripts, and
2053 then compiling and linking the binaries for the Exim monitor (if configured), a
2054 number of utility programs, and finally Exim itself. The command \*make
2055 makefile*\ can be used to force a rebuild of the make file in the build
2056 directory, should this ever be necessary.
2058 If you have problems building Exim, check for any comments there may be in the
2059 \(README)\ file concerning your operating system, and also take a look at the
2061 [(A HREF="FAQ.html")]
2067 where some common problems are covered.
2071 .section Overriding build-time options for Exim
2072 .index build-time options, overriding
2073 .rset SECToverride "~~chapter.~~section"
2074 The main make file that is created at the beginning of the building process
2075 consists of the concatenation of a number of files which set configuration
2076 values, followed by a fixed set of \*make*\ instructions. If a value is set
2077 more than once, the last setting overrides any previous ones. This provides a
2078 convenient way of overriding defaults. The files that are concatenated are, in
2081 \(OS/Makefile-Default)\
2082 \(OS/Makefile-)\<<ostype>>
2084 \(Local/Makefile-)\<<ostype>>
2085 \(Local/Makefile-)\<<archtype>>
2086 \(Local/Makefile-)\<<ostype>>-<<archtype>>
2087 \(OS/Makefile-Base)\
2089 .index \(Local/Makefile)\
2090 where <<ostype>> is the operating system type and <<archtype>> is the
2091 .index building Exim||operating system type
2092 .index building Exim||architecture type
2093 architecture type. \(Local/Makefile)\ is required to exist, and the building
2094 process fails if it is absent. The other three \(Local)\ files are optional,
2095 and are often not needed.
2097 The values used for <<ostype>> and <<archtype>> are obtained from scripts
2098 called \(scripts/os-type)\ and \(scripts/arch-type)\ respectively. If either of
2099 the environment variables \\EXIM@_OSTYPE\\ or \\EXIM@_ARCHTYPE\\ is set, their
2100 values are used, thereby providing a means of forcing particular settings.
2101 Otherwise, the scripts try to get values from the \uname\ command. If this
2102 fails, the shell variables \\OSTYPE\\ and \\ARCHTYPE\\ are inspected. A number
2103 of $it{ad hoc} transformations are then applied, to produce the standard names
2104 that Exim expects. You can run these scripts directly from the shell in order
2105 to find out what values are being used on your system.
2108 \(OS/Makefile-Default)\ contains comments about the variables that are set
2109 therein. Some (but not all) are mentioned below. If there is something that
2110 needs changing, review the contents of this file and the contents of the make
2111 file for your operating system (\(OS/Makefile-<<ostype>>)\) to see what the
2115 .index building Exim||overriding default settings
2116 If you need to change any of the values that are set in \(OS/Makefile-Default)\
2117 or in \(OS/Makefile-<<ostype>>)\, or to add any new definitions, you do not
2118 need to change the original files. Instead, you should make the changes by
2119 putting the new values in an appropriate \(Local)\ file. For example,
2120 .index Tru64-Unix build-time settings
2121 when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2122 formerly DEC-OSF1) operating system, it is necessary to specify that the C
2123 compiler is called \*cc*\ rather than \*gcc*\. Also, the compiler must be
2124 called with the option \-std1-\, to make it recognize some of the features of
2125 Standard C that Exim uses. (Most other compilers recognize Standard C by
2126 default.) To do this, you should create a file called \(Local/Makefile-OSF1)\
2127 containing the lines
2132 If you are compiling for just one operating system, it may be easier to put
2133 these lines directly into \(Local/Makefile)\.
2135 Keeping all your local configuration settings separate from the distributed
2136 files makes it easy to transfer them to new versions of Exim simply by copying
2137 the contents of the \(Local)\ directory.
2140 .index NIS lookup type||including support for
2141 .index NIS@+ lookup type||including support for
2142 .index LDAP||including support for
2143 .index lookup||inclusion in binary
2144 Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2145 lookup, but not all systems have these components installed, so the default is
2146 not to include the relevant code in the binary. All the different kinds of file
2147 and database lookup that Exim supports are implemented as separate code modules
2148 which are included only if the relevant compile-time options are set. In the
2149 case of LDAP, NIS, and NIS+, the settings for \(Local/Makefile)\ are:
2155 and similar settings apply to the other lookup types. They are all listed in
2156 \(src/EDITME)\. In most cases the relevant include files and interface
2157 libraries need to be installed before compiling Exim.
2158 .index cdb||including support for
2159 However, in the case of cdb, which is included in the binary only if
2163 is set, the code is entirely contained within Exim, and no external include
2164 files or libraries are required. When a lookup type is not included in the
2165 binary, attempts to configure Exim to use it cause run time configuration
2168 .index Perl||including support for
2169 Exim can be linked with an embedded Perl interpreter, allowing Perl
2170 subroutines to be called during string expansion. To enable this facility,
2174 must be defined in \(Local/Makefile)\. Details of this facility are given in
2177 .index X11 libraries, location of
2178 The location of the X11 libraries is something that varies a lot between
2179 operating systems, and of course there are different versions of X11 to cope
2180 with. Exim itself makes no use of X11, but if you are compiling the Exim
2181 monitor, the X11 libraries must be available.
2182 The following three variables are set in \(OS/Makefile-Default)\:
2185 XINCLUDE=-I$(X11)/include
2186 XLFLAGS=-L$(X11)/lib
2188 These are overridden in some of the operating-system configuration files. For
2189 example, in \(OS/Makefile-SunOS5)\ there is
2192 XINCLUDE=-I$(X11)/include
2193 XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2195 If you need to override the default setting for your operating system, place a
2196 definition of all three of these variables into your
2197 \(Local/Makefile-<<ostype>>)\ file.
2199 .index \\EXTRALIBS\\
2200 If you need to add any extra libraries to the link steps, these can be put in a
2201 variable called \\EXTRALIBS\\, which appears in all the link commands, but by
2202 default is not defined. In contrast, \\EXTRALIBS@_EXIM\\ is used only on the
2203 command for linking the main Exim binary, and not for any associated utilities.
2204 .index DBM||libraries, configuration for building
2205 There is also \\DBMLIB\\, which appears in the link commands for binaries that
2206 use DBM functions (see also section ~~SECTdb). Finally, there is
2207 \\EXTRALIBS@_EXIMON\\, which appears only in the link step for the Exim monitor
2208 binary, and which can be used, for example, to include additional X11
2211 .index configuration file||editing
2212 The make file copes with rebuilding Exim correctly if any of the configuration
2213 files are edited. However, if an optional configuration file is deleted, it is
2214 necessary to touch the associated non-optional file (that is, \(Local/Makefile)\
2215 or \(Local/eximon.conf)\) before rebuilding.
2217 .section OS-specific header files
2219 .index building Exim||OS-specific C header files
2220 The \(OS)\ directory contains a number of files with names of the form
2221 \(os.h-<<ostype>>)\. These are system-specific C header files that should not
2222 normally need to be changed. There is a list of macro settings that are
2223 recognized in the file \(OS/os.configuring)\, which should be consulted if you
2224 are porting Exim to a new operating system.
2227 .section Overriding build-time options for the monitor
2228 .index building Eximon||overriding default options
2229 A similar process is used for overriding things when building the Exim monitor,
2230 where the files that are involved are
2232 \(OS/eximon.conf-Default)\
2233 \(OS/eximon.conf-)\<<ostype>>
2234 \(Local/eximon.conf)\
2235 \(Local/eximon.conf-)\<<ostype>>
2236 \(Local/eximon.conf-)\<<archtype>>
2237 \(Local/eximon.conf-)\<<ostype>>-<<archtype>>
2239 .index \(Local/eximon.conf)\
2240 As with Exim itself, the final three files need not exist, and in this case the
2241 \(OS/eximon.conf-<<ostype>>)\ file is also optional. The default values in
2242 \(OS/eximon.conf-Default)\ can be overridden dynamically by setting environment
2243 variables of the same name, preceded by \\EXIMON@_\\. For example, setting
2244 \\EXIMON@_LOG@_DEPTH\\ in the environment overrides the value of
2245 \\LOG@_DEPTH\\ at run time.
2249 .section Installing Exim binaries and scripts
2250 .index installing Exim
2251 .index \\BIN@_DIRECTORY\\
2252 The command \*make install*\ runs the \*exim@_install*\ script with no
2253 arguments. The script copies binaries and utility scripts into the directory
2254 whose name is specified by the \\BIN@_DIRECTORY\\ setting in
2257 Exim's run time configuration file is named by the \\CONFIGURE@_FILE\\ setting
2258 .index \\CONFIGURE@_FILE\\
2259 in \(Local/Makefile)\. If this names a single file, and the file does not
2260 exist, the default configuration file \(src/configure.default)\ is copied there
2261 by the installation script. If a run time configuration file already exists, it
2262 is left alone. If \\CONFIGURE@_FILE\\ is a colon-separated list, naming several
2263 alternative files, no default is installed.
2265 .index system aliases file
2266 .index \(/etc/aliases)\
2267 One change is made to the default configuration file when it is installed: the
2268 default configuration contains a router that references a system aliases file.
2269 The path to this file is set to the value specified by
2270 \\SYSTEM@_ALIASES@_FILE\\ in \(Local/Makefile)\ (\(/etc/aliases)\ by default).
2271 If the system aliases file does not exist, the installation script creates it,
2272 and outputs a comment to the user.
2274 The created file contains no aliases, but it does contain comments about the
2275 aliases a site should normally have. Mail aliases have traditionally been
2276 kept in \(/etc/aliases)\. However, some operating systems are now using
2277 \(/etc/mail/aliases)\. You should check if yours is one of these, and change
2278 Exim's configuration if necessary.
2280 The default configuration uses the local host's name as the only local domain,
2281 and is set up to do local deliveries into the shared directory \(/var/mail)\,
2282 running as the local user. System aliases and \(.forward)\ files in users' home
2283 directories are supported, but no NIS or NIS+ support is configured. Domains
2284 other than the name of the local host are routed using the DNS, with delivery
2287 The install script copies files only if they are newer than the files they are
2288 going to replace. The Exim binary is required to be owned by root and have the
2290 .index setuid||installing Exim with
2291 for normal configurations. Therefore, you must run \*make install*\ as root so
2292 that it can set up the Exim binary in this way. However, in some special
2293 situations (for example, if a host is doing no local deliveries) it may be
2294 possible to run Exim without making the binary setuid root (see chapter
2295 ~~CHAPsecurity for details).
2297 It is possible to install Exim for special purposes (such as building a binary
2298 distribution) in a private part of the file system. You can do this by a
2301 make DESTDIR=/some/directory/ install
2303 This has the effect of pre-pending the specified directory to all the file
2304 paths, except the name of the system aliases file that appears in the default
2305 configuration. (If a default alias file is created, its name \*is*\ modified.)
2306 For backwards compatibility, \\ROOT\\ is used if \\DESTDIR\\ is not set,
2307 but this usage is deprecated.
2309 .index installing Exim||what is not installed
2310 Running \*make install*\ does not copy the Exim 4 conversion script
2311 \*convert4r4*\, or the \*pcretest*\ test program. You will probably run the
2312 first of these only once (if you are upgrading from Exim 3), and the second
2313 isn't really part of Exim. None of the documentation files in the \(doc)\
2314 directory are copied, except for the info files when you have set
2315 \\INFO@_DIRECTORY\\, as described in section ~~SECTinsinfdoc below.
2317 For the utility programs, old versions are renamed by adding the suffix \(.O)\
2318 to their names. The Exim binary itself, however, is handled differently. It is
2319 installed under a name that includes the version number and the compile number,
2320 for example \(exim-~~version-1)\. The script then arranges for a symbolic link
2321 called \(exim)\ to point to the binary. If you are updating a previous version
2322 of Exim, the script takes care to ensure that the name \(exim)\ is never absent
2323 from the directory (as seen by other processes).
2325 .index installing Exim||testing the script
2326 If you want to see what the \*make install*\ will do before running it for
2327 real, you can pass the \-n-\ option to the installation script by this command:
2329 make INSTALL_ARG=-n install
2331 The contents of the variable \\INSTALL@_ARG\\ are passed to the installation
2332 script. You do not need to be root to run this test. Alternatively, you can run
2333 the installation script directly, but this must be from within the build
2334 directory. For example, from the top-level Exim directory you could use this
2337 (cd build-SunOS5-5.5.1-sparc; ../scripts/exim@_install -n)
2340 .index installing Exim||install script options
2341 There are two other options that can be supplied to the installation script.
2343 \-no@_chown-\ bypasses the call to change the owner of the installed binary
2344 to root, and the call to make it a setuid binary.
2346 \-no@_symlink-\ bypasses the setting up of the symbolic link \(exim)\ to the
2349 \\INSTALL@_ARG\\ can be used to pass these options to the script. For example:
2351 make INSTALL_ARG=-no_symlink install
2354 The installation script can also be given arguments specifying which files are
2355 to be copied. For example, to install just the Exim binary, and nothing else,
2356 without creating the symbolic link, you could use:
2358 make INSTALL_ARG='-no_symlink exim' install
2362 .section Installing info documentation
2363 .rset SECTinsinfdoc "~~chapter.~~section"
2364 .index installing Exim||\*info*\ documentation
2365 Not all systems use the GNU \*info*\ system for documentation, and for this
2366 reason, the Texinfo source of Exim's documentation is not included in the main
2367 distribution. Instead it is available separately from the ftp site (see section
2370 If you have defined \\INFO@_DIRECTORY\\ in \(Local/Makefile)\ and the Texinfo
2371 source of the documentation is found in the source tree, running \*make
2372 install*\ automatically builds the info files and installs them.
2375 .section Setting up the spool directory
2376 .index spool directory||creating
2377 When it starts up, Exim tries to create its spool directory if it does not
2378 exist. The Exim uid and gid are used for the owner and group of the spool
2379 directory. Sub-directories are automatically created in the spool directory as
2385 .index testing||installation
2386 Having installed Exim, you can check that the run time configuration file is
2387 syntactically valid by running the following command, which assumes that the
2388 Exim binary directory is within your \\PATH\\ environment variable:
2392 If there are any errors in the configuration file, Exim outputs error messages.
2393 Otherwise it outputs the version number and build date,
2394 the DBM library that is being used, and information about which drivers and
2395 other optional code modules are included in the binary.
2396 Some simple routing tests can be done by using the address testing option. For
2399 exim -bt <<local username>>
2401 should verify that it recognizes a local mailbox, and
2403 exim -bt <<remote address>>
2405 a remote one. Then try getting it to deliver mail, both locally and remotely.
2406 This can be done by passing messages directly to Exim, without going through a
2407 user agent. For example:
2409 exim -v postmaster@@your.domain.example
2410 From: user@@your.domain.example
2411 To: postmaster@@your.domain.example
2412 Subject: Testing Exim
2414 This is a test message.
2417 The \-v-\ option causes Exim to output some verification of what it is doing.
2418 In this case you should see copies of three log lines, one for the message's
2419 arrival, one for its delivery, and one containing `Completed'.
2421 .index delivery||problems with
2422 If you encounter problems, look at Exim's log files (\*mainlog*\ and
2423 \*paniclog*\) to see if there is any relevant information there. Another source
2424 of information is running Exim with debugging turned on, by specifying the
2425 \-d-\ option. If a message is stuck on Exim's spool, you can force a delivery
2426 with debugging turned on by a command of the form
2428 exim -d -M <<message-id>>
2430 You must be root or an `admin user' in order to do this. The \-d-\ option
2431 produces rather a lot of output, but you can cut this down to specific areas.
2432 For example, if you use \-d-all+route-\ only the debugging information relevant
2433 to routing is included. (See the \-d-\ option in chapter ~~CHAPcommandline for
2438 One specific problem that has shown up on some sites is the inability to do
2439 local deliveries into a shared mailbox directory, because it does not have the
2440 `sticky bit' set on it. By default, Exim tries to create a lock file before
2441 writing to a mailbox file, and if it cannot create the lock file, the delivery
2442 is deferred. You can get round this either by setting the `sticky bit' on the
2443 directory, or by setting a specific group for local deliveries and allowing
2444 that group to create files in the directory (see the comments above the
2445 \%local@_delivery%\ transport in the default configuration file). Another
2446 approach is to configure Exim not to use lock files, but just to rely on
2447 \*fcntl()*\ locking instead. However, you should do this only if all user
2448 agents also use \*fcntl()*\ locking. For further discussion of locking issues,
2449 see chapter ~~CHAPappendfile.
2451 One thing that cannot be tested on a system that is already running an MTA is
2452 the receipt of incoming SMTP mail on the standard SMTP port. However, the
2453 \-oX-\ option can be used to run an Exim daemon that listens on some other
2454 port, or \*inetd*\ can be used to do this. The \-bh-\ option and the
2455 \*exim@_checkaccess*\ utility can be used to check out policy controls on
2458 Testing a new version on a system that is already running Exim can most easily
2459 be done by building a binary with a different \\CONFIGURE@_FILE\\ setting. From
2460 within the run time configuration, all other file and directory names
2461 that Exim uses can be altered, in order to keep it entirely clear of the
2464 .section Replacing another MTA with Exim
2465 .index replacing another MTA
2466 Building and installing Exim for the first time does not of itself put it in
2467 general use. The name by which the system's MTA is called by mail user agents
2468 is either \(/usr/sbin/sendmail)\, or \(/usr/lib/sendmail)\ (depending on the
2469 operating system), and it is necessary to make this name point to the \*exim*\
2470 binary in order to get the user agents to pass messages to Exim. This is
2471 normally done by renaming any existing file and making \(/usr/sbin/sendmail)\
2472 or \(/usr/lib/sendmail)\
2473 .index symbolic link||to \*exim*\ binary
2474 a symbolic link to the \*exim*\ binary. It is a good idea to remove any setuid
2475 privilege and executable status from the old MTA. It is then necessary to stop
2476 and restart the mailer daemon, if one is running.
2478 .index FreeBSD, MTA indirection
2479 .index \(/etc/mail/mailer.conf)\
2480 Some operating systems have introduced alternative ways of switching MTAs. For
2481 example, if you are running FreeBSD, you need to edit the file
2482 \(/etc/mail/mailer.conf)\ instead of setting up a symbolic link as just
2483 described. A typical example of the contents of this file for running Exim is
2486 sendmail /usr/exim/bin/exim
2487 send-mail /usr/exim/bin/exim
2488 mailq /usr/exim/bin/exim -bp
2489 newaliases /usr/bin/true
2492 Once you have set up the symbolic link, or edited \(/etc/mail/mailer.conf)\,
2493 your Exim installation is `live'. Check it by sending a message from your
2494 favourite user agent.
2496 You should consider what to tell your users about the change of MTA. Exim may
2497 have different capabilities to what was previously running, and there are
2498 various operational differences such as the text of messages produced by
2499 command line options and in bounce messages. If you allow your users to make
2500 use of Exim's filtering capabilities, you should make the document entitled
2502 [(A HREF="filter.html")]
2504 \*Exim's interface to mail filtering*\
2511 .section Upgrading Exim
2512 .index upgrading Exim
2513 If you are already running Exim on your host, building and installing a new
2514 version automatically makes it available to MUAs, or any other programs that
2515 call the MTA directly. However, if you are running an Exim daemon, you do need
2516 to send it a HUP signal, to make it re-exec itself, and thereby pick up the new
2517 binary. You do not need to stop processing mail in order to install a new
2521 .section Stopping the Exim daemon on Solaris
2522 .index Solaris||stopping Exim on
2523 The standard command for stopping the mailer daemon on Solaris is
2525 /etc/init.d/sendmail stop
2527 If \(/usr/lib/sendmail)\ has been turned into a symbolic link, this script
2528 fails to stop Exim because it uses the command \*ps -e*\ and greps the output
2529 for the text `sendmail'; this is not present because the actual program name
2530 (that is, `exim') is given by the \*ps*\ command with these options. A solution
2531 is to replace the line that finds the process id with something like
2533 pid=`cat /var/spool/exim/exim-daemon.pid`
2535 to obtain the daemon's pid directly from the file that Exim saves it in.
2537 Note, however, that stopping the daemon does not `stop Exim'. Messages can
2538 still be received from local processes, and if automatic delivery is configured
2539 (the normal case), deliveries will still occur.
2546 . ============================================================================
2547 .chapter The Exim command line
2548 .set runningfoot "command line"
2549 .rset CHAPcommandline ~~chapter
2550 .index command line||options
2551 .index options||command line
2553 Exim's command line takes the standard Unix form of a sequence of options,
2554 each starting with a hyphen character, followed by a number of arguments. The
2555 options are compatible with the main options of Sendmail, and there are also
2556 some additional options, some of which are compatible with Smail 3. Certain
2557 combinations of options do not make sense, and provoke an error if used.
2558 The form of the arguments depends on which options are set.
2560 .section Setting options by program name
2562 If Exim is called under the name \*mailq*\, it behaves as if the option \-bp-\
2563 were present before any other options.
2564 The \-bp-\ option requests a listing of the contents of the mail queue on the
2566 This feature is for compatibility with some systems that contain a command of
2567 that name in one of the standard libraries, symbolically linked to
2568 \(/usr/sbin/sendmail)\ or \(/usr/lib/sendmail)\.
2571 If Exim is called under the name \*rsmtp*\ it behaves as if the option \-bS-\
2572 were present before any other options, for compatibility with Smail. The \-bS-\
2573 option is used for reading in a number of messages in batched SMTP format.
2576 If Exim is called under the name \*rmail*\ it behaves as if the \-i-\ and
2577 \-oee-\ options were present before any other options, for compatibility with
2578 Smail. The name \*rmail*\ is used as an interface by some UUCP systems.
2582 If Exim is called under the name \*runq*\ it behaves as if the option \-q-\ were
2583 present before any other options, for compatibility with Smail. The \-q-\
2584 option causes a single queue runner process to be started.
2586 .index \*newaliases*\
2587 .index alias file||building
2588 .index Sendmail compatibility||calling Exim as \*newaliases*\
2589 If Exim is called under the name \*newaliases*\ it behaves as if the option
2590 \-bi-\ were present before any other options, for compatibility with Sendmail.
2591 This option is used for rebuilding Sendmail's alias file. Exim does not have
2592 the concept of a single alias file, but can be configured to run a given
2593 command if called with the \-bi-\ option.
2595 .section Trusted and admin users
2596 .rset SECTtrustedadmin "~~chapter.~~section"
2597 Some Exim options are available only to \*trusted users*\ and others are
2598 available only to \*admin users*\. In the description below, the phrases `Exim
2599 user' and `Exim group' mean the user and group defined by \\EXIM@_USER\\ and
2600 \\EXIM@_GROUP\\ in \(Local/Makefile)\ or set by the \exim@_user\ and
2601 \exim@_group\ options. These do not necessarily have to use the name `exim'.
2604 .index trusted user||definition of
2605 .index user||trusted, definition of
2606 The trusted users are root, the Exim user, any user listed in the
2607 \trusted@_users\ configuration option, and any user whose current group or any
2608 supplementary group is one of those listed in the \trusted@_groups\
2609 configuration option. Note that the Exim group is not automatically trusted.
2612 .index envelope sender
2613 Trusted users are always permitted to use the \-f-\ option or a leading `From '
2614 line to specify the envelope sender of a message that is passed to Exim through
2615 the local interface (see the \-bm-\ and \-f-\ options below). See the
2616 \untrusted@_set@_sender\ option for a way of permitting non-trusted users to
2617 set envelope senders.
2618 .index ::From:: header line
2619 .index ::Sender:: header line
2620 For a trusted user, there is never any check on the contents of the ::From::
2621 header line, and a ::Sender:: line is never added. Furthermore, any existing
2622 ::Sender:: line in incoming local (non-TCP/IP) messages is not removed.
2624 Trusted users may also specify a host name, host address, interface address,
2625 protocol name, ident value, and authentication data when submitting a message
2626 locally. Thus, they are able to insert messages into Exim's queue locally that
2627 have the characteristics of messages received from a remote host. Untrusted
2628 users may in some circumstances use \-f-\, but can never set the other values
2629 that are available to trusted users.
2631 .index user||admin, definition of
2632 .index admin user||definition of
2633 The admin users are root, the Exim user, and any user that is a member of the
2634 Exim group or of any group listed in the \admin@_groups\ configuration option.
2635 The current group does not have to be one of these groups.
2637 Admin users are permitted to list the queue, and to carry out certain
2638 operations on messages, for example, to force delivery failures. It is also
2639 necessary to be an admin user in order to see the full information provided by
2640 the Exim monitor, and full debugging output.
2642 By default, the use of the \-M-\, \-q-\, \-R-\, and \-S-\ options to cause Exim
2643 to attempt delivery of messages on its queue is restricted to admin users.
2644 However, this restriction can be relaxed by setting the \prod@_requires@_admin\
2645 option false (that is, specifying \no@_prod@_requires@_admin\).
2647 Similarly, the use of the \-bp-\ option to list all the messages in the queue
2648 is restricted to admin users unless \queue@_list@_requires@_admin\ is set
2652 \**Warning**\: If you configure your system so that admin users are able to
2653 edit Exim's configuration file, you are giving those users an easy way of
2654 getting root. There is further discussion of this issue at the start of chapter
2659 .section Command line options
2660 The command options are described in alphabetical order below.
2665 .index options||command line, terminating
2666 This is a pseudo-option whose only purpose is to terminate the options and
2667 therefore to cause subsequent command line items to be treated as arguments
2668 rather than options, even if they begin with hyphens.
2671 This option causes Exim to output a few sentences stating what it is.
2672 The same output is generated if the Exim binary is called with no options and
2676 .index 8-bit characters
2677 .index Sendmail compatibility||8-bit characters
2678 This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2679 clean; it ignores this option.
2683 .index SMTP listener
2685 This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
2686 the \-bd-\ option is combined with the \-q-\<<time>> option, to specify that
2687 the daemon should also initiate periodic queue runs.
2689 The \-bd-\ option can be used only by an admin user. If either of the \-d-\
2690 (debugging) or \-v-\ (verifying) options are set, the daemon does not
2691 disconnect from the controlling terminal. When running this way, it can be
2692 stopped by pressing ctrl-C.
2694 By default, Exim listens for incoming connections to the standard SMTP port on
2695 all the host's running interfaces. However, it is possible to listen on other
2696 ports, on multiple ports, and only on specific interfaces. Chapter
2697 ~~CHAPinterfaces contains a description of the options that control this.
2699 .index daemon||process id (pid)
2700 .index pid (process id)||of daemon
2701 When a listening daemon is started without the use of \-oX-\ (that is, without
2702 overriding the normal configuration), it writes its process id to a file called
2703 \(exim-daemon.pid)\ in Exim's spool directory. This location can be overridden
2704 by setting \\PID@_FILE@_PATH\\ in \(Local/Makefile)\. The file is written while
2705 Exim is still running as root.
2707 When \-oX-\ is used on the command line to start a listening daemon, the
2708 process id is not written to the normal pid file path. However, \-oP-\ can be
2709 used to specify a path on the command line if a pid file is required.
2712 The \\SIGHUP\\ signal can be used to cause the daemon to re-exec itself. This
2713 should be done whenever Exim's configuration file, or any file that is
2714 incorporated into it by means of the \.include\ facility, is changed, and also
2715 whenever a new version of Exim is installed. It is not necessary to do this
2716 when other files that are referenced from the configuration (for example, alias
2717 files) are changed, because these are reread each time they are used.
2720 This option has the same effect as \-bd-\ except that it never disconnects from
2721 the controlling terminal, even when no debugging is specified.
2724 .index testing||string expansion
2725 .index expansion||testing
2726 Run Exim in expansion testing mode. Exim discards its root privilege, to
2727 prevent ordinary users from using this mode to read otherwise inaccessible
2728 files. If no arguments are given, Exim runs interactively, prompting for lines
2729 of data. Long expressions can be split over several lines by using backslash
2731 As in Exim's run time configuration, whitespace at the start of continuation
2734 Each argument or data line is passed through the string expansion mechanism,
2735 and the result is output. Variable values from the configuration file (for
2736 example, \$qualify@_domain$\) are available, but no message-specific values
2737 (such as \$domain$\) are set, because no message is being processed.
2739 .option bF #<<filename>>
2740 .index system filter||testing
2741 .index testing||system filter
2742 This option is the same as \-bf-\ except that it assumes that the filter being
2743 tested is a system filter. The additional commands that are available only in
2744 system filters are recognized.
2746 .option bf #<<filename>>
2747 .index filter||testing
2748 .index testing||filter file
2749 .index forward file||testing
2750 .index testing||forward file
2751 .index Sieve filter||testing
2752 This option runs Exim in filter testing mode; the file is the filter file to be
2753 tested, and a test message must be supplied on the standard input. If there are
2754 no message-dependent tests in the filter, an empty file can be supplied. If a
2755 system filter file is being tested, \-bF-\ should be used instead of \-bf-\. If
2756 the test file does not begin with
2757 one of the special lines
2762 it is taken to be a normal \(.forward)\ file, and is tested for validity under
2763 that interpretation. See sections ~~SECTitenonfilred to ~~SECTspecitredli for a
2764 description of the possible contents of non-filter redirection lists.
2766 The result of an Exim command that uses \-bf-\, provided no errors are
2767 detected, is a list of the actions that Exim would try to take if presented
2768 with the message for real. More details of filter testing are given in the
2769 separate document entitled \*Exim's interfaces to mail filtering*\.
2772 .index envelope sender
2773 .index \-f-\ option||for filter testing
2774 When testing a filter file, the envelope sender can be set by the \-f-\ option,
2775 or by a `From ' line at the start of the test message. Various parameters that
2776 would normally be taken from the envelope recipient address of the message can
2777 be set by means of additional command line options. These are:
2784 . The odd alignment here gets it lined up in the man page.
2785 \-bfd-\ $t <<domain>> $t $rm{default is the qualify domain}
2786 \-bfl-\ $t <<local@_part>> $t $rm{default is the logged in user}
2787 \-bfp-\ $t <<local@_part@_prefix>> $t $rm{default is null}
2788 \-bfs-\ $t <<local@_part@_suffix>> $t $rm{default is null}
2790 The local part should always be set to the incoming address with any prefix or
2791 suffix stripped, because that is how it appears to the filter when a message is
2792 actually being delivered.
2794 .option bh #<<IP address>>
2795 .index testing||incoming SMTP
2796 .index SMTP||testing incoming
2797 .index testing||relay control
2798 .index relaying||testing configuration
2799 .index policy control||testing
2800 .index debugging||\-bh-\ option
2801 This option runs a fake SMTP session as if from the given IP address, using the
2802 standard input and output. The IP address may include a port number at the end,
2803 after a full stop. For example:
2805 exim -bh 10.9.8.7.1234
2806 exim -bh fe80::a00:20ff:fe86:a061.5678
2808 Comments as to what is going on are written to the standard error file. These
2809 include lines beginning with `LOG' for anything that would have been logged.
2810 This facility is provided for testing configuration options for incoming
2811 messages, to make sure they implement the required policy. For example, you can
2812 test your relay controls using \-bh-\.
2815 \**Warning 1**\: You cannot test features of the configuration that rely on
2816 ident (RFC 1413) callouts. These cannot be done when testing using
2817 \-bh-\ because there is no incoming SMTP connection.
2819 \**Warning 2**\: Address verification callouts (see section ~~SECTcallver) are
2820 also skipped when testing using \-bh-\. If you want these callouts to occur,
2821 use \-bhc-\ instead.
2823 Messages supplied during the testing session are discarded, and nothing is
2824 written to any of the real log files. There may be pauses when DNS (and other)
2825 lookups are taking place, and of course these may time out. The \-oMi-\ option
2826 can be used to specify a specific IP interface and port if this is important.
2828 The \*exim@_checkaccess*\ utility is a `packaged' version of \-bh-\ whose
2829 output just states whether a given recipient address from a given host is
2830 acceptable or not. See section ~~SECTcheckaccess.
2832 .option bhc #<<IP address>>
2833 This option operates in the same way as \-bh-\, except that address
2834 verification callouts are performed if required. This includes consulting and
2835 updating the callout cache database.
2838 .index alias file||building
2839 .index building alias file
2840 .index Sendmail compatibility||\-bi-\ option
2841 Sendmail interprets the \-bi-\ option as a request to rebuild its alias file.
2842 Exim does not have the concept of a single alias file, and so it cannot mimic
2843 this behaviour. However, calls to \(/usr/lib/sendmail)\ with the \-bi-\ option
2844 tend to appear in various scripts such as NIS make files, so the option must be
2847 If \-bi-\ is encountered, the command specified by the \bi@_command\
2848 configuration option is run, under the uid and gid of the caller of Exim. If
2849 the \-oA-\ option is used, its value is passed to the command as an argument.
2850 The command set by \bi@_command\ may not contain arguments. The command can use
2851 the \*exim@_dbmbuild*\ utility, or some other means, to rebuild alias files if
2852 this is required. If the \bi@_command\ option is not set, calling Exim with
2856 .index local message reception
2857 This option runs an Exim receiving process that accepts an incoming,
2858 locally-generated message on the current input. The recipients are given as the
2859 command arguments (except when \-t-\ is also present -- see below). Each
2860 argument can be a comma-separated list of RFC 2822 addresses. This is the
2861 default option for selecting the overall action of an Exim call; it is assumed
2862 if no other conflicting option is present.
2864 If any addresses in the message are unqualified (have no domain), they are
2865 qualified by the values of the \qualify@_domain\ or \qualify@_recipient\
2866 options, as appropriate. The \-bnq-\ option (see below) provides a way of
2867 suppressing this for special cases.
2869 Policy checks on the contents of local messages can be enforced by means of the
2870 non-SMTP ACL. See chapter ~~CHAPACL for details.
2871 .index return code||for \-bm-\
2872 The return code is zero if the message is successfully accepted. Otherwise, the
2873 action is controlled by the \-oe$it{x}-\ option setting -- see below.
2875 .index message||format
2876 .index format||message
2878 .index UUCP||`From' line
2879 .index Sendmail compatibility||`From' line
2880 The format of the message must be as defined in RFC 2822, except that, for
2881 compatibility with Sendmail and Smail, a line in one of the forms
2883 From sender Fri Jan 5 12:55 GMT 1997
2884 From sender Fri, 5 Jan 97 12:55:01
2886 (with the weekday optional, and possibly with additional text after the date)
2887 is permitted to appear at the start of the message. There appears to be no
2888 authoritative specification of the format of this line. Exim recognizes it by
2889 matching against the regular expression defined by the \uucp@_from@_pattern\
2890 option, which can be changed if necessary.
2891 .index \-f-\ option||overriding `From' line
2892 The specified sender is treated as if it were given as the argument to the
2893 \-f-\ option, but if a \-f-\ option is also present, its argument is used in
2894 preference to the address taken from the message. The caller of Exim must be a
2895 trusted user for the sender of a message to be set in this way.
2898 .index address||qualification, suppressing
2899 By default, Exim automatically qualifies unqualified addresses (those
2900 without domains) that appear in messages that are submitted locally (that
2901 is, not over TCP/IP). This qualification applies both to addresses in
2902 envelopes, and addresses in header lines. Sender addresses are qualified using
2903 \qualify@_domain\, and recipient addresses using \qualify@_recipient\ (which
2904 defaults to the value of \qualify@_domain\).
2906 Sometimes, qualification is not wanted. For example, if \-bS-\ (batch SMTP) is
2907 being used to re-submit messages that originally came from remote hosts after
2908 content scanning, you probably do not want to qualify unqualified addresses in
2909 header lines. (Such lines will be present only if you have not enabled a header
2910 syntax check in the appropriate ACL.)
2912 The \-bnq-\ option suppresses all qualification of unqualified addresses in
2913 messages that originate on the local host. When this is used, unqualified
2914 addresses in the envelope provoke errors (causing message rejection) and
2915 unqualified addresses in header lines are left alone.
2919 .index configuration options, extracting
2920 .index options||configuration, extracting
2921 If this option is given with no arguments, it causes the values of all Exim's
2922 main configuration options to be written to the standard output. The values
2923 of one or more specific options can be requested by giving their names as
2924 arguments, for example:
2926 exim -bP qualify@_domain hold@_domains
2928 However, any option setting that is preceded by the word `hide' in the
2929 configuration file is not shown in full, except to an admin user. For other
2930 users, the output is as in this example:
2932 mysql_servers = <value not displayable>
2934 If \configure@_file\ is given as an argument, the name of the run time
2935 configuration file is output.
2936 If a list of configuration files was supplied, the value that is output here
2937 is the name of the file that was actually used.
2939 .index daemon||process id (pid)
2940 .index pid (process id)||of daemon
2941 If \log__file__path\ or \pid@_file@_path\ are given, the names of the
2942 directories where log files and daemon pid files are written are output,
2943 respectively. If these values are unset, log files are written in a
2944 sub-directory of the spool directory called \log\, and the pid file is written
2945 directly into the spool directory.
2947 If \-bP-\ is followed by a name preceded by \"+"\, for example,
2949 exim -bP +local_domains
2951 it searches for a matching named list of any type (domain, host, address, or
2952 local part) and outputs what it finds.
2954 .index options||router, extracting
2955 .index options||transport, extracting
2956 If one of the words \router\, \transport\, or \authenticator\ is given,
2957 followed by the name of an appropriate driver instance, the option settings for
2958 that driver are output. For example:
2960 exim -bP transport local@_delivery
2962 The generic driver options are output first, followed by the driver's private
2963 options. A list of the names of drivers of a particular type can be obtained by
2964 using one of the words \router@_list\, \transport@_list\, or
2965 \authenticator@_list\, and a complete list of all drivers with their option
2966 settings can be obtained by using \routers\, \transports\, or \authenticators\.
2970 .index queue||listing messages on
2971 .index listing||messages on the queue
2972 This option requests a listing of the contents of the mail queue on the
2973 standard output. If the \-bp-\ option is followed by a list of message ids,
2974 just those messages are listed. By default, this option can be used only by an
2975 admin user. However, the \queue__list__requires__admin\ option can be set false
2976 to allow any user to see the queue.
2978 Each message on the queue is displayed as in the following example:
2980 25m 2.9K 0t5C6f-0000c8-00 <alice@@wonderland.fict.example>
2981 red.king@@looking-glass.fict.example
2984 .index message||size in queue listing
2985 .index size||of message
2986 The first line contains the length of time the message has been on the queue
2987 (in this case 25 minutes), the size of the message (2.9K), the unique local
2988 identifier for the message, and the message sender, as contained in the
2989 envelope. For bounce messages, the sender address is empty, and appears as
2990 `<>'. If the message was submitted locally by an untrusted user who overrode
2991 the default sender address, the user's login name is shown in parentheses
2992 before the sender address.
2993 .index frozen messages||in queue listing
2994 If the message is frozen (attempts to deliver it are suspended) then the text
2995 `$*$$*$$*$ frozen $*$$*$$*$' is displayed at the end of this line.
2997 The recipients of the message (taken from the envelope, not the headers) are
2998 displayed on subsequent lines. Those addresses to which the message has already
2999 been delivered are marked with the letter D. If an original address gets
3000 expanded into several addresses via an alias or forward file, the original is
3001 displayed with a D only when deliveries for all of its child addresses are
3006 This option operates like \-bp-\, but in addition it shows delivered addresses
3007 that were generated from the original top level address(es) in each message by
3008 alias or forwarding operations. These addresses are flagged with `+D' instead
3013 .index queue||count of messages on
3014 This option counts the number of messages on the queue, and writes the total
3015 to the standard output. It is restricted to admin users, unless
3016 \queue__list__requires__admin\ is set false.
3020 This option operates like \-bp-\, but the output is not sorted into
3021 chronological order of message arrival. This can speed it up when there are
3022 lots of messages on the queue, and is particularly useful if the output is
3023 going to be post-processed in a way that doesn't need the sorting.
3026 This option is a combination of \-bpr-\ and \-bpa-\.
3029 This option is a combination of \-bpr-\ and \-bpu-\.
3033 This option operates like \-bp-\ but shows only undelivered top-level addresses
3034 for each message displayed. Addresses generated by aliasing or forwarding are
3035 not shown, unless the message was deferred after processing by a router with
3036 the \one@_time\ option set.
3040 .index testing||retry configuration
3041 .index retry||configuration testing
3042 This option is for testing retry rules, and it must be followed by up to three
3043 arguments. It causes Exim to look for a retry rule that matches the values
3044 and to write it to the standard output. For example:
3046 exim -brt bach.comp.mus.example
3047 Retry rule: *.comp.mus.example F,2h,15m; F,4d,30m;
3049 See chapter ~~CHAPretry for a description of Exim's retry rules. The first
3050 argument, which is required, can be a complete address in the form
3051 \*local@_part@@domain*\, or it can be just a domain name. The second argument is
3052 an optional second domain name; if no retry rule is found for the first
3053 argument, the second is tried. This ties in with Exim's behaviour when looking
3054 for retry rules for remote hosts -- if no rule is found that matches the host,
3055 one that matches the mail domain is sought. The final argument is the name of a
3056 specific delivery error, as used in setting up retry rules, for example
3060 .index testing||rewriting
3061 .index rewriting||testing
3062 This option is for testing address rewriting rules, and it must be followed by
3063 a single argument, consisting of either a local part without a domain, or a
3064 complete address with a fully qualified domain. Exim outputs how this address
3065 would be rewritten for each possible place it might appear. See chapter
3066 ~~CHAPrewrite for further details.
3069 .index SMTP||batched incoming
3070 .index batched SMTP input
3071 This option is used for batched SMTP input, which is an alternative interface
3072 for non-interactive local message submission. A number of messages can be
3073 submitted in a single run. However, despite its name, this is not really SMTP
3074 input. Exim reads each message's envelope from SMTP commands on the standard
3075 input, but generates no responses. If the caller is trusted, or
3076 \untrusted@_set@_sender\ is set, the senders in the SMTP \\MAIL\\ commands are
3077 believed; otherwise the sender is always the caller of Exim.
3079 The message itself is read from the standard input, in SMTP format (leading
3080 dots doubled), terminated by a line containing just a single dot. An error is
3081 provoked if the terminating dot is missing. A further message may then follow.
3083 As for other local message submissions, the contents of incoming batch SMTP
3084 messages can be checked using the non-SMTP ACL (see chapter ~~CHAPACL).
3085 Unqualified addresses are automatically qualified using \qualify@_domain\ and
3086 \qualify@_recipient\, as appropriate, unless the \-bnq-\ option is used.
3088 Some other SMTP commands are recognized in the input. \\HELO\\ and \\EHLO\\ act
3089 as \\RSET\\; \\VRFY\\, \\EXPN\\, \\ETRN\\, and \\HELP\\ act as \\NOOP\\;
3090 \\QUIT\\ quits, ignoring the rest of the standard input.
3092 If any error is encountered, reports are written to the standard output and
3093 error streams, and Exim gives up immediately.
3094 .index return code||for \-bS-\
3095 The return code is 0 if no error was detected; it is 1 if one or more messages
3096 were accepted before the error was detected; otherwise it is 2.
3098 More details of input using batched SMTP are given in section
3099 ~~SECTincomingbatchedSMTP.
3102 .index SMTP||local input
3103 .index local SMTP input
3104 This option causes Exim to accept one or more messages by reading SMTP commands
3105 on the standard input, and producing SMTP replies on the standard output. SMTP
3106 policy controls, as defined in ACLs (see chapter ~~CHAPACL) are applied.
3108 Some user agents use this interface as a way of passing locally-generated
3109 messages to the MTA.
3110 .index sender||source of
3111 In this usage, if the caller of Exim is trusted, or \untrusted@_set@_sender\ is
3112 set, the senders of messages are taken from the SMTP \\MAIL\\ commands.
3113 Otherwise the content of these commands is ignored and the sender is set up as
3114 the calling user. Unqualified addresses are automatically qualified using
3115 \qualify@_domain\ and \qualify@_recipient\, as appropriate, unless the \-bnq-\
3119 The \-bs-\ option is also used to run Exim from \*inetd*\, as an alternative to
3120 using a listening daemon. Exim can distinguish the two cases by checking
3121 whether the standard input is a TCP/IP socket. When Exim is called from
3122 \*inetd*\, the source of the mail is assumed to be remote, and the comments
3123 above concerning senders and qualification do not apply. In this situation,
3124 Exim behaves in exactly the same way as it does when receiving a message via
3125 the listening daemon.
3128 .index testing||addresses
3129 .index address||testing
3130 This option runs Exim in address testing mode, in which each argument is taken
3131 as an address to be tested for deliverability. The results are written to the
3133 If a test fails, and the caller is not an admin user, no details of the
3134 failure are output, because these might contain sensitive information such as
3135 usernames and passwords for database lookups.
3137 If no arguments are given, Exim runs in an interactive manner, prompting with a
3138 right angle bracket for addresses to be tested. Each address is handled as if
3139 it were the recipient address of a message (compare the \-bv-\ option). It is
3140 passed to the routers and the result is written to the standard output.
3141 However, any router that has \no@_address@_test\ set is bypassed. This can
3142 make \-bt-\ easier to use for genuine routing tests if your first router passes
3143 everything to a scanner program.
3145 .index return code||for \-bt-\
3146 The return code is 2 if any address failed outright; it is 1 if no address
3147 failed outright but at least one could not be resolved for some reason. Return
3148 code 0 is given only when all addresses succeed.
3150 \**Warning**\: \-bt-\ can only do relatively simple testing. If any of the
3151 routers in the configuration makes any tests on the sender address of a
3153 .index \-f-\ option||for address testing
3154 you can use the \-f-\ option to set an appropriate sender when running
3155 \-bt-\ tests. Without it, the sender is assumed to be the calling user at the
3156 default qualifying domain. However, if you have set up (for example) routers
3157 whose behaviour depends on the contents of an incoming message, you cannot test
3158 those conditions using \-bt-\. The \-N-\ option provides a possible way of
3162 .index version number of Exim, verifying
3163 This option causes Exim to write the current version number, compilation
3164 number, and compilation date of the \*exim*\ binary to the standard output.
3165 It also lists the DBM library this is being used, the optional modules (such as
3166 specific lookup types), the drivers that are included in the binary, and the
3167 name of the run time configuration file that is in use.
3170 .index verifying||address, using \-bv-\
3171 .index address||verification
3172 This option runs Exim in address verification mode, in which each argument is
3173 taken as an address to be verified. During normal operation, verification
3174 happens mostly as a consequence processing a \verify\ condition in an ACL (see
3175 chapter ~~CHAPACL). If you want to test an entire ACL, see the \-bh-\ option.
3177 If verification fails, and the caller is not an admin user, no details of the
3178 failure are output, because these might contain sensitive information such as
3179 usernames and passwords for database lookups.
3181 If no arguments are given, Exim runs in an interactive manner, prompting with a
3182 right angle bracket for addresses to be verified. Verification differs from
3183 address testing (the \-bt-\ option) in that routers that have \no@_verify\ set
3184 are skipped, and if the address is accepted by a router that has \fail@_verify\
3185 set, verification fails. The address is verified as a recipient if \-bv-\ is
3186 used; to test verification for a sender address, \-bvs-\ should be used.
3188 If the \-v-\ option is not set, the output consists of a single line for each
3189 address, stating whether it was verified or not, and giving a reason in the
3190 latter case. Otherwise, more details are given of how the address has been
3191 handled, and in the case of address redirection, all the generated addresses
3192 are also considered. Without \-v-\, generating more than one address by
3193 redirection causes verification to end sucessfully.
3195 .index return code||for \-bv-\
3196 The return code is 2 if any address failed outright; it is 1 if no address
3197 failed outright but at least one could not be resolved for some reason. Return
3198 code 0 is given only when all addresses succeed.
3200 If any of the routers in the configuration makes any tests on the sender
3201 address of a message, you should use the \-f-\ option to set an appropriate
3202 sender when running \-bv-\ tests. Without it, the sender is assumed to be the
3203 calling user at the default qualifying domain.
3206 This option acts like \-bv-\, but verifies the address as a sender rather
3207 than a recipient address. This affects any rewriting and qualification that
3210 .option C #<<filelist>>
3211 .index configuration file||alternate
3212 .index \\CONFIGURE@_FILE\\
3213 .index alternate configuration file
3214 This option causes Exim to find the run time configuration file from the given
3215 list instead of from the list specified by the \\CONFIGURE@_FILE\\
3216 compile-time setting. Usually, the list will consist of just a single file
3217 name, but it can be a colon-separated list of names. In this case, the first
3218 file that exists is used. Failure to open an existing file stops Exim from
3219 proceeding any further along the list, and an error is generated.
3221 When this option is used by a caller other than root or the Exim user,
3222 and the list is different from the compiled-in list, Exim gives up
3223 its root privilege immediately, and runs with the real and effective uid and
3224 gid set to those of the caller.
3225 However, if \\ALT@_CONFIG@_ROOT@_ONLY\\ is defined in \(Local/Makefile)\, root
3226 privilege is retained for \-C-\ only if the caller of Exim is root.
3227 This option is not set by default.
3229 Setting \\ALT@_CONFIG@_ROOT@_ONLY\\ locks out the possibility of testing a
3230 configuration using \-C-\ right through message reception and delivery, even if
3231 the caller is root. The reception works, but by that time, Exim is running as
3232 the Exim user, so when it re-execs to regain privilege for the delivery, the
3233 use of \-C-\ causes privilege to be lost. However, root can test reception and
3234 delivery using two separate commands (one to put a message on the queue, using
3235 \-odq-\, and another to do the delivery, using \-M-\).
3237 If \\ALT@_CONFIG@_PREFIX\\ is defined \(in Local/Makefile)\, it specifies a
3238 prefix string with which any file named in a \-C-\ command line option
3239 must start. In addition, the file name must not contain the sequence \"/../"\.
3240 However, if the value of the \-C-\ option is identical to the value of
3241 \\CONFIGURE@_FILE\\ in \(Local/Makefile)\, Exim ignores \-C-\ and proceeds as
3242 usual. There is no default setting for \\ALT@_CONFIG@_PREFIX\\; when it is
3243 unset, any file name can be used with \-C-\.
3245 \\ALT@_CONFIG@_PREFIX\\ can be used to confine alternative configuration files
3246 to a directory to which only root has access. This prevents someone who has
3247 broken into the Exim account from running a privileged Exim with an arbitrary
3250 The \-C-\ facility is useful for ensuring that configuration files are
3251 syntactically correct, but cannot be used for test deliveries, unless the
3252 caller is privileged, or unless it is an exotic configuration that does not
3253 require privilege. No check is made on the owner or group of the files
3254 specified by this option.
3256 .option D <<macro>>=<<value>>
3257 .index macro||setting on command line
3258 This option can be used to override macro definitions in the configuration file
3259 (see section ~~SECTmacrodefs). However, like \-C-\, if it is used by an
3260 unprivileged caller, it causes Exim to give up its root privilege.
3261 If \\DISABLE@_D@_OPTION\\ is defined in \(Local/Makefile)\, the use of \-D-\ is
3262 completely disabled, and its use causes an immediate error exit.
3264 The entire option (including equals sign if present) must all be within one
3265 command line item. \-D-\ can be used to set the value of a macro to the empty
3266 string, in which case the equals sign is optional. These two commands are
3272 To include spaces in a macro definition item, quotes must be used. If you use
3273 quotes, spaces are permitted around the macro name and the equals sign. For
3276 exim '-D ABC = something' ...
3278 \-D-\ may be repeated up to 10 times on a command line.
3280 .option d <<debug options>>
3281 .index debugging||list of selectors
3282 .index debugging||\-d-\ option
3283 This option causes debugging information to be written to the standard
3284 error stream. It is restricted to admin users because debugging output may show
3285 database queries that contain password information. Also, the details of users'
3286 filter files should be protected. When \-d-\ is used, \-v-\ is assumed. If
3287 \-d-\ is given on its own, a lot of standard debugging data is output. This can
3288 be reduced, or increased to include some more rarely needed information, by
3289 following \-d-\ with a string made up of names preceded by plus or minus
3290 characters. These add or remove sets of debugging data, respectively. For
3291 example, \-d+filter-\ adds filter debugging, whereas \-d-all+filter-\ selects
3292 only filter debugging. The available debugging categories are:
3296 . The odd formatting of the lines below is deliberate. It does not affect the
3297 . SGCAL output, but by putting in the space it keeps things aligned in the man
3298 . page that is automatically generated from this text.
3300 acl $t $rm{ACL interpretation}
3301 auth $t $rm{authenticators}
3302 deliver $t $rm{general delivery logic}
3303 dns $t $rm{DNS lookups (see also resolver)}
3304 dnsbl $t $rm{DNS black list (aka RBL) code}
3305 exec $t $rm{arguments for \execv@(@)\ calls}
3306 expand $t $rm{detailed debugging for string expansions}
3307 filter $t $rm{filter handling}
3308 hints@_lookup $t $rm{hints data lookups}
3309 host@_lookup $t $rm{all types of name-to-IP address handling}
3310 ident $t $rm{ident lookup}
3311 interface $t $rm{lists of local interfaces}
3312 lists $t $rm{matching things in lists}
3313 load $t $rm{system load checks}
3314 local@_scan $t $rm{can be used by \*local@_scan()*\ (see chapter ~~CHAPlocalscan)}
3315 lookup $t $rm{general lookup code and all lookups}
3316 memory $t $rm{memory handling}
3317 pid $t $rm{add pid to debug output lines}
3318 process@_info $t $rm{setting info for the process log}
3319 queue@_run $t $rm{queue runs}
3320 receive $t $rm{general message reception logic}
3321 resolver $t $rm{turn on the DNS resolver's debugging output}
3322 retry $t $rm{retry handling}
3323 rewrite $t $rm{address rewriting}
3324 route $t $rm{address routing}
3325 timestamp $t $rm{add timestamp to debug output lines}
3326 tls $t $rm{TLS logic}
3327 transport $t $rm{transports}
3328 uid $t $rm{changes of uid/gid and looking up uid/gid}
3329 verify $t $rm{address verification logic}
3331 all $t $rm{all of the above, and also \-v-\}
3333 .index resolver, debugging output
3334 .index DNS||resolver, debugging output
3335 The \"resolver"\ option produces output only if the DNS resolver was compiled
3336 with \\DEBUG\\ enabled. This is not the case in some operating systems. Also,
3337 unfortunately, debugging output from the DNS resolver is written to stdout
3340 The default (\-d-\ with no argument) omits \"expand"\, \"filter"\,
3341 \"interface"\, \"load"\, \"memory"\, \"pid"\, \"resolver"\, and \"timestamp"\.
3342 However, the \"pid"\ selector is forced when debugging is turned on for a
3343 daemon, which then passes it on to any re-executed Exims. Exim also
3344 automatically adds the pid to debug lines when several remote deliveries are
3347 The \"timestamp"\ selector causes the current time to be inserted at the start
3348 of all debug output lines. This can be useful when trying to track down delays
3351 If the \debug@_print\ option is set in any driver, it produces output whenever
3352 any debugging is selected, or if \-v-\ is used.
3355 This is an obsolete option that is now a no-op. It used to affect the way Exim
3356 handled CR and LF characters in incoming messages. What happens now is
3357 described in section ~~SECTlineendings.
3361 .index bounce message||generating
3362 This option specifies that an incoming message is a locally-generated delivery
3363 failure report. It is used internally by Exim when handling delivery failures
3364 and is not intended for external use. Its only effect is to stop Exim
3365 generating certain messages to the postmaster, as otherwise message cascades
3366 could occur in some situations. As part of the same option, a message id may
3367 follow the characters \-E-\. If it does, the log entry for the receipt of the
3368 new message contains the id, following `R=', as a cross-reference.
3371 There are a number of Sendmail options starting with \-oe-\ which seem to be
3372 called by various programs without the leading \o\ in the option. For example,
3373 the \vacation\ program uses \-eq-\. Exim treats all options of the form
3374 \-e$it{x}-\ as synonymous with the corresponding \-oe$it{x}-\ options.
3376 .option F #<<string>>
3378 .index name||of sender
3379 This option sets the sender's full name for use when a locally-generated
3380 message is being accepted. In the absence of this option, the user's \*gecos*\
3381 entry from the password data is used. As users are generally permitted to alter
3382 their \*gecos*\ entries, no security considerations are involved. White space
3383 between \-F-\ and the <<string>> is optional.
3385 .option f #<<address>>
3386 .index sender||address
3387 .index address||sender
3389 .index envelope sender
3390 .index user||trusted
3391 This option sets the address of the envelope sender of a locally-generated
3392 message (also known as the return path). The option can normally be used only
3393 by a trusted user, but \untrusted@_set@_sender\ can be set to allow untrusted
3394 users to use it. In the absence of \-f-\, or if the caller is not allowed to
3395 use it, the sender of a local message is set to the caller's login name at the
3396 default qualify domain.
3398 There is one exception to the restriction on the use of \-f-\: an empty sender
3399 can be specified by any user, to create a message that can never provoke a
3400 bounce. An empty sender can be specified either as an empty string, or as a
3401 pair of angle brackets with nothing between them, as in these examples of shell
3404 exim -f '<>' user@domain
3405 exim -f "" user@domain
3407 In addition, the use of \-f-\ is not restricted when testing a filter file with
3408 \-bf-\ or when testing or verifying addresses using the \-bt-\ or \-bv-\
3411 Allowing untrusted users to change the sender address does not of itself make
3412 it possible to send anonymous mail. Exim still checks that the ::From:: header
3413 refers to the local user, and if it does not, it adds a ::Sender:: header,
3414 though this can be overridden by setting \no@_local@_from@_check\.
3417 White space between \-f-\ and the <<address>> is optional
3418 (that is, they can be given as two arguments or one combined argument).
3419 The sender of a locally-generated message can also be set (when permitted) by
3420 an initial `From ' line in the message -- see the description of \-bm-\ above
3421 -- but if \-f-\ is also present, it overrides `From'.
3424 .index Sendmail compatibility||\-G-\ option ignored
3425 This is a Sendmail option which is ignored by Exim.
3427 .option h #<<number>>
3428 .index Sendmail compatibility||\-h-\ option ignored
3429 This option is accepted for compatibility with Sendmail, but has no effect. (In
3430 Sendmail it overrides the `hop count' obtained by counting ::Received::
3434 .index Solaris||\*mail*\ command
3435 .index dot||in incoming, non-SMTP message
3436 This option, which has the same effect as \-oi-\, specifies that a dot on a
3437 line by itself should not terminate an incoming, non-SMTP message. I can find
3438 no documentation for this option in Solaris 2.4 Sendmail, but the \*mailx*\
3439 command in Solaris 2.4 uses it. See also \-ti-\.
3441 .option M #<<message id>>#<<message id>> ...
3442 .index forcing delivery
3443 .index delivery||forcing attempt
3444 .index frozen messages||forcing delivery
3445 This option requests Exim to run a delivery attempt on each message in turn. If
3446 any of the messages are frozen, they are automatically thawed before the
3447 delivery attempt. The settings of \queue@_domains\, \queue@_smtp@_domains\, and
3448 \hold@_domains\ are ignored.
3449 .index hints database||overriding retry hints
3450 Retry hints for any of the addresses are
3451 overridden -- Exim tries to deliver even if the normal retry time has not yet
3452 been reached. This option requires the caller to be an admin user. However,
3453 there is an option called \prod@_requires@_admin\ which can be set false to
3454 relax this restriction (and also the same requirement for the \-q-\, \-R-\, and
3458 .option Mar #<<message id>>#<<address>>#<<address>> ...
3459 .index message||adding recipients
3460 .index recipient||adding
3461 This option requests Exim to add the addresses to the list of recipients of the
3462 message (`ar' for `add recipients'). The first argument must be a message id,
3463 and the remaining ones must be email addresses. However, if the message is
3464 active (in the middle of a delivery attempt), it is not altered. This option
3465 can be used only by an admin user.
3467 .index SMTP||passed connection
3468 .index SMTP||multiple deliveries
3469 .index multiple SMTP deliveries
3470 .option MC #<<transport>>#<<hostname>>#<<sequence number>>#<<message id>>
3471 This option is not intended for use by external callers. It is used internally
3472 by Exim to invoke another instance of itself to deliver a waiting message using
3473 an existing SMTP connection, which is passed as the standard input. Details are
3474 given in chapter ~~CHAPSMTP. This must be the final option, and the caller must
3475 be root or the Exim user in order to use it.
3478 This option is not intended for use by external callers. It is used internally
3479 by Exim in conjunction with the \-MC-\ option. It signifies that the connection
3480 to the remote host has been authenticated.
3483 This option is not intended for use by external callers. It is used internally
3484 by Exim in conjunction with the \-MC-\ option. It signifies that the server to
3485 which Exim is connected supports pipelining.
3487 .option MCQ #<<process id>> <<pipe fd>>
3488 This option is not intended for use by external callers. It is used internally
3489 by Exim in conjunction with the \-MC-\ option when the original delivery was
3490 started by a queue runner. It passes on the process id of the queue runner,
3491 together with the file descriptor number of an open pipe. Closure of the pipe
3492 signals the final completion of the sequence of processes that are passing
3493 messages through the same SMTP connection.
3496 This option is not intended for use by external callers. It is used internally
3497 by Exim in conjunction with the \-MC-\ option, and passes on the fact that the
3498 SMTP \\SIZE\\ option should be used on messages delivered down the existing
3502 This option is not intended for use by external callers. It is used internally
3503 by Exim in conjunction with the \-MC-\ option, and passes on the fact that the
3504 host to which Exim is connected supports TLS encryption.
3506 .option Mc #<<message id>>#<<message id>> ...
3507 .index hints database||not overridden by \-Mc-\
3508 .index delivery||manually started, not forced
3509 This option requests Exim to run a delivery attempt on each message in turn,
3510 but unlike the \-M-\ option, it does check for retry hints, and respects any
3511 that are found. This option is not very useful to external callers. It is
3512 provided mainly for internal use by Exim when it needs to re-invoke itself in
3513 order to regain root privilege for a delivery (see chapter ~~CHAPsecurity).
3514 However, \-Mc-\ can be useful when testing, in order to run a delivery that
3515 respects retry times and other options such as \hold@_domains\ that are
3516 overridden when \-M-\ is used. Such a delivery does not count as a queue run.
3517 If you want to run a specific delivery as if in a queue run, you should use
3518 \-q-\ with a message id argument. A distinction between queue run deliveries
3519 and other deliveries is made in one or two places.
3521 .option Mes #<<message id>>#<<address>>
3522 .index message||changing sender
3523 .index sender||changing
3524 This option requests Exim to change the sender address in the message to the
3525 given address, which must be a fully qualified address or `<>' (`es' for `edit
3526 sender'). There must be exactly two arguments. The first argument must be a
3527 message id, and the second one an email address. However, if the message is
3528 active (in the middle of a delivery attempt), its status is not altered. This
3529 option can be used only by an admin user.
3531 .option Mf #<<message id>>#<<message id>> ...
3532 .index freezing messages
3533 .index message||manually freezing
3534 This option requests Exim to mark each listed message as `frozen'. This
3535 prevents any delivery attempts taking place until the message is `thawed',
3536 either manually or as a result of the \auto@_thaw\ configuration option.
3537 However, if any of the messages are active (in the middle of a delivery
3538 attempt), their status is not altered. This option can be used only by an admin
3541 .option Mg #<<message id>>#<<message id>> ...
3542 .index giving up on messages
3543 .index message||abandoning delivery attempts
3544 .index delivery||abandoning further attempts
3545 This option requests Exim to give up trying to deliver the listed messages,
3546 including any that are frozen. However, if any of the messages are active,
3547 their status is not altered.
3548 For non-bounce messages, a delivery error message is sent to the sender,
3549 containing the text `cancelled by administrator'. Bounce messages are just
3551 This option can be used only by an admin user.
3553 .option Mmad #<<message id>>#<<message id>> ...
3554 .index delivery||cancelling all
3555 This option requests Exim to mark all the recipient addresses in the messages
3556 as already delivered (`mad' for `mark all delivered'). However, if any message
3557 is active (in the middle of a delivery attempt), its status is not altered.
3558 This option can be used only by an admin user.
3560 .option Mmd #<<message id>>#<<address>>#<<address>> ...
3561 .index delivery||cancelling by address
3562 .index recipient||removing
3563 .index removing recipients
3564 This option requests Exim to mark the given addresses as already delivered
3565 (`md' for `mark delivered'). The first argument must be a message id, and the
3566 remaining ones must be email addresses. These are matched to recipient
3567 addresses in the message in a case-sensitive manner. If the message is active
3568 (in the middle of a delivery attempt), its status is not altered. This option
3569 can be used only by an admin user.
3571 .option Mrm #<<message id>>#<<message id>> ...
3572 .index removing messages
3573 .index abandoning mail
3574 .index message||manually discarding
3575 This option requests Exim to remove the given messages from the queue. No
3576 bounce messages are sent; each message is simply forgotten. However, if any of
3577 the messages are active, their status is not altered. This option can be used
3578 only by an admin user or by the user who originally caused the message to be
3579 placed on the queue.
3581 .option Mt #<<message id>>#<<message id>> ...
3582 .index thawing messages
3583 .index unfreezing messages
3584 .index frozen messages||thawing
3585 .index message||thawing frozen
3586 This option requests Exim to `thaw' any of the listed messages that are
3587 `frozen', so that delivery attempts can resume. However, if any of the messages
3588 are active, their status is not altered. This option can be used only by an
3591 .option Mvb #<<message id>>
3592 .index listing||message body
3593 .index message||listing body of
3594 This option causes the contents of the message body (-D) spool file to be
3595 written to the standard output. This option can be used only by an admin user.
3597 .option Mvh #<<message id>>
3598 .index listing||message headers
3599 .index header lines||listing
3600 .index message||listing header lines
3601 This option causes the contents of the message headers (-H) spool file to be
3602 written to the standard output. This option can be used only by an admin user.
3604 .option Mvl #<<message id>>
3605 .index listing||message log
3606 .index message||listing message log
3607 This option causes the contents of the message log spool file to be written to
3608 the standard output. This option can be used only by an admin user.
3611 This is apparently a synonym for \-om-\ that is accepted by Sendmail, so Exim
3612 treats it that way too.
3615 .index debugging||\-N-\ option
3616 .index debugging||suppressing delivery
3617 This is a debugging option that inhibits delivery of a message at the transport
3618 level. It implies \-v-\. Exim goes through many of the motions of delivery --
3619 it just doesn't actually transport the message, but instead behaves as if it
3620 had successfully done so. However, it does not make any updates to the retry
3621 database, and the log entries for deliveries are flagged with `$*$>' rather
3624 Because \-N-\ discards any message to which it applies, only root or the Exim
3625 user are allowed to use it with \-bd-\, \-q-\, \-R-\ or \-M-\. In other words,
3626 an ordinary user can use it only when supplying an incoming message to which it
3627 will apply. Although transportation never fails when \-N-\ is set, an address
3628 may be deferred because of a configuration problem on a transport, or a routing
3629 problem. Once \-N-\ has been used for a delivery attempt, it sticks to the
3630 message, and applies to any subsequent delivery attempts that may happen for
3634 .index Sendmail compatibility||\-n-\ option ignored
3635 This option is interpreted by Sendmail to mean `no aliasing'. It is ignored by
3639 This option is interpreted by Sendmail to mean `set option`. It is ignored by
3642 .option oA #<<file name>>
3643 .index Sendmail compatibility||\-oA-\ option
3644 This option is used by Sendmail in conjunction with \-bi-\ to specify an
3645 alternative alias file name. Exim handles \-bi-\ differently; see the
3648 .index SMTP||passed connection
3650 .index SMTP||multiple deliveries
3651 .index multiple SMTP deliveries
3652 This is a debugging option which limits the maximum number of messages that can
3653 be delivered down one SMTP connection, overriding the value set in any \%smtp%\
3654 transport. If <<n>> is omitted, the limit is set to 1.
3657 .index background delivery
3658 .index delivery||in the background
3659 This option applies to all modes in which Exim accepts incoming messages,
3660 including the listening daemon. It requests `background' delivery of such
3661 messages, which means that the accepting process automatically starts delivery
3662 process for each message received, but does not wait for the delivery process
3663 to complete. This is the default action if none of the \-od-\ options are
3666 If one of the queueing options in the configuration file
3667 (\queue@_only\ or \queue@_only@_file\, for example) is in effect, \-odb-\
3668 overrides it if \queue@_only@_override\ is set true, which is the default
3669 setting. If \queue@_only@_override\ is set false, \-odb-\ has no effect.
3672 .index foreground delivery
3673 .index delivery||in the foreground
3674 This option requests `foreground' (synchronous) delivery when Exim has accepted
3675 a locally-generated message. (For the daemon it is exactly the same as
3676 \-odb-\.) A delivery process is automatically started to deliver the
3677 message, and Exim waits for it to complete before proceeding.
3678 However, like \-odb-\, this option has no effect if \queue@_only@_override\ is
3679 false and one of the queueing options in the configuration file is in effect.
3682 This option is synonymous with \-odf-\. It is provided for compatibility with
3686 .index non-immediate delivery
3687 .index delivery||suppressing immediate
3688 .index queueing incoming messages
3689 This option applies to all modes in which Exim accepts incoming messages,
3690 including the listening daemon. It specifies that the accepting process should
3691 not automatically start a delivery process for each message received. Messages
3692 are placed on the queue, and remain there until a subsequent queue runner
3693 process encounters them.
3694 There are several configuration options (such as \queue@_only\) that can be
3695 used to queue incoming messages under certain conditions. This option overrides
3696 all of them and also \-odqs-\. It always forces queueing.
3699 .index SMTP||delaying delivery
3700 This option is a hybrid between \-odb-\/\-odi-\ and \-odq-\.
3701 However, like \-odb-\ and \-odi-\, this option has no effect if
3702 \queue@_only@_override\ is false and one of the queueing options in the
3703 configuration file is in effect.
3705 When \-odqs-\ does operate, a delivery process is started for each incoming
3706 message, in the background by default, but in the foreground if \-odi-\ is also
3708 The recipient addresses are routed, and local deliveries are done in the normal
3709 way. However, if any SMTP deliveries are required, they are not done at this
3710 time, so the message remains on the queue until a subsequent queue runner
3711 process encounters it. Because routing was done, Exim knows which messages are
3712 waiting for which hosts, and so a number of messages for the same host can be
3713 sent in a single SMTP connection. The \queue@_smtp@_domains\ configuration
3714 option has the same effect for specific domains. See also the \-qq-\ option.
3717 .index error||reporting
3718 If an error is detected while a non-SMTP message is being received (for
3719 example, a malformed address), the error is reported to the sender in a mail
3721 .index return code||for \-oee-\
3722 Provided this error message is successfully sent, the Exim receiving process
3723 exits with a return code of zero. If not, the return code is 2 if the problem
3724 is that the original message has no recipients, or 1 any other error. This is
3725 the default \-oe$it{x}-\ option if Exim is called as \*rmail*\.
3728 .index error||reporting
3729 .index return code||for \-oem-\
3730 This is the same as \-oee-\, except that Exim always exits with a non-zero
3731 return code, whether or not the error message was successfully sent.
3732 This is the default \-oe$it{x}-\ option, unless Exim is called as \*rmail*\.
3735 .index error||reporting
3736 If an error is detected while a non-SMTP message is being received, the
3737 error is reported by writing a message to the standard error file (stderr).
3738 .index return code||for \-oep-\
3739 The return code is 1 for all errors.
3742 .index error||reporting
3743 This option is supported for compatibility with Sendmail, but has the same
3747 .index error||reporting
3748 This option is supported for compatibility with Sendmail, but has the same
3752 .index dot||in incoming, non-SMTP message
3753 This option, which has the same effect as \-i-\, specifies that a dot on a line
3754 by itself should not terminate an incoming, non-SMTP message.
3755 Otherwise, a single dot does terminate, though Exim does no special processing
3756 for other lines that start with a dot.
3757 This option is set by default if Exim is called as \*rmail*\. See also \-ti-\.
3760 This option is treated as synonymous with \-oi-\.
3762 .option oMa #<<host address>>
3763 .index sender||host address, specifying for local message
3764 A number of options starting with \-oM-\ can be used to set values associated
3765 with remote hosts on locally-submitted messages (that is, messages not received
3766 over TCP/IP). These options can be used by any caller in conjunction with the
3769 \-bf-\, \-bF-\, \-bt-\, or \-bv-\ testing options. In other circumstances, they
3770 are ignored unless the caller is trusted.
3772 The \-oMa-\ option sets the sender host address. This may include a port number
3773 at the end, after a full stop (period). For example:
3775 exim -bs -oMa 10.9.8.7.1234
3777 An alternative syntax is to enclose the IP address in square brackets, followed
3778 by a colon and the port number:
3780 exim -bs -oMa [10.9.8.7]:1234
3782 The IP address is placed in the \$sender@_host@_address$\ variable, and the
3783 port, if present, in \$sender@_host@_port$\.
3785 .option oMaa #<<name>>
3786 .index authentication||name, specifying for local message
3787 See \-oMa-\ above for general remarks about the \-oM-\ options. The \-oMaa-\
3788 option sets the value of \$sender@_host@_authenticated$\ (the authenticator
3789 name). See chapter ~~CHAPSMTPAUTH for a discussion of SMTP authentication.
3791 .option oMai #<<string>>
3792 .index authentication||id, specifying for local message
3793 See \-oMa-\ above for general remarks about the \-oM-\ options. The \-oMai-\
3795 value of \$authenticated@_id$\ (the id that was authenticated).
3796 This overrides the default value (the caller's login id) for messages from
3797 local sources. See chapter ~~CHAPSMTPAUTH for a discussion of authenticated
3800 .option oMas #<<address>>
3801 .index authentication||sender, specifying for local message
3802 See \-oMa-\ above for general remarks about the \-oM-\ options. The \-oMas-\
3803 option sets the authenticated sender value
3804 in \$authenticated@_sender$\.
3805 It overrides the sender address that is created from the caller's login id for
3806 messages from local sources. See chapter ~~CHAPSMTPAUTH for a discussion of
3807 authenticated senders.
3809 .option oMi #<<interface address>>
3810 .index interface||address, specifying for local message
3811 See \-oMa-\ above for general remarks about the \-oM-\ options. The \-oMi-\
3812 option sets the IP interface address value. A port number may be included,
3813 using the same syntax as for \-oMa-\.
3814 The interface address is placed in \$interface@_address$\ and the port number,
3815 if present, in \$interface@_port$\.
3817 .option oMr #<<protocol name>>
3818 .index protocol||incoming, specifying for local message
3819 See \-oMa-\ above for general remarks about the \-oM-\ options. The \-oMr-\
3820 option sets the received protocol value
3821 in \$received@_protocol$\.
3822 However, this applies only when \-bs-\ is not used. For interactive SMTP input,
3823 the protocol is determined by whether \\EHLO\\ or \\HELO\\ is used, and is
3824 always either `local-esmtp' or `local-smtp'. For \-bS-\ (batch SMTP) however,
3825 the protocol can be set by \-oMr-\.
3827 .option oMs #<<host name>>
3828 .index sender||host name, specifying for local message
3829 See \-oMa-\ above for general remarks about the \-oM-\ options. The \-oMs-\
3830 option sets the sender host name
3831 in \$sender@_host@_name$\. When this option is present, Exim does not attempt
3832 to look up a host name from an IP address; it uses the name it is given.
3834 .option oMt #<<ident string>>
3835 .index sender||ident string, specifying for local message
3836 See \-oMa-\ above for general remarks about the \-oM-\ options. The \-oMt-\
3837 option sets the sender ident value
3838 in \$sender@_ident$\.
3839 The default setting for local callers is the login id of the calling process.
3842 .index Sendmail compatibility||\-om-\ option ignored
3843 In Sendmail, this option means `me too', indicating that the sender of a
3844 message should receive a copy of the message if the sender appears in an alias
3845 expansion. Exim always does this, so the option does nothing.
3848 .index Sendmail compatibility||\-oo-\ option ignored
3849 This option is ignored. In Sendmail it specifies `old style headers', whatever
3852 .option oP #<<path>>
3853 .index pid (process id)||of daemon
3854 .index daemon||process id (pid)
3855 This option is useful only in conjunction with \-bd-\ or \-q-\ with a time
3856 value. The option specifies the file to which the process id of the daemon is
3857 written. When \-oX-\ is used with \-bd-\, or when \-q-\ with a time is used
3858 without \-bd-\, this is the only way of causing Exim to write a pid file,
3859 because in those cases, the normal pid file is not used.
3861 .option or #<<time>>
3862 .index timeout||for non-SMTP input
3863 This option sets a timeout value for incoming non-SMTP messages. If it is not
3864 set, Exim will wait forever for the standard input. The value can also be set
3865 by the \receive@_timeout\ option. The format used for specifying times is
3866 described in section ~~SECTtimeformat.
3868 .option os #<<time>>
3869 .index timeout||for SMTP input
3870 .index SMTP||timeout, input
3871 This option sets a timeout value for incoming SMTP messages. The timeout
3872 applies to each SMTP command and block of data. The value can also be set by
3873 the \smtp@_receive@_timeout\ option; it defaults to 5 minutes. The format used
3874 for specifying times is described in section ~~SECTtimeformat.
3877 This option has exactly the same effect as \-v-\.
3879 .option oX #<<number or string>>
3880 .index TCP/IP||setting listening ports
3881 .index TCP/IP||setting listening interfaces
3882 .index port||receiving TCP/IP
3883 This option is relevant only when the \-bd-\ (start listening daemon) option is
3884 also given. It controls which ports and interfaces the daemon uses. Details of
3885 the syntax, and how it interacts with configuration file options, are given in
3886 chapter ~~CHAPinterfaces. When \-oX-\ is used to start a daemon, no pid file is
3887 written unless \-oP-\ is also present to specify a pid file name.
3890 .index Perl||starting the interpreter
3891 This option applies when an embedded Perl interpreter is linked with Exim (see
3892 chapter ~~CHAPperl). It overrides the setting of the \perl@_at@_start\ option,
3893 forcing the starting of the interpreter to be delayed until it is needed.
3896 .index Perl||starting the interpreter
3897 This option applies when an embedded Perl interpreter is linked with Exim (see
3898 chapter ~~CHAPperl). It overrides the setting of the \perl@_at@_start\ option,
3899 forcing the starting of the interpreter to occur as soon as Exim is started.
3901 .option p<<rval>>:<<sval>>
3902 For compatibility with Sendmail, this option
3905 -oMr <<rval>> -oMs <<sval>>
3907 It sets the incoming protocol and host name (for trusted callers). The
3908 host name and its colon can be omitted when only the protocol is to be set.
3909 Note the Exim already has two private options, \-pd-\ and \-ps-\, that refer to
3910 embedded Perl. It is therefore impossible to set a protocol value of \"p"\ or
3911 \"s"\ using this option (but that does not seem a real limitation).
3914 .index queue runner||starting manually
3915 This option is normally restricted to admin users. However, there is a
3916 configuration option called \prod@_requires@_admin\ which can be set false to
3917 relax this restriction (and also the same requirement for the \-M-\, \-R-\, and
3920 .index queue runner||description of operation
3921 The \-q-\ option starts one queue runner process. This scans the queue of
3922 waiting messages, and runs a delivery process for each one in turn. It waits
3923 for each delivery process to finish before starting the next one. A delivery
3924 process may not actually do any deliveries if the retry times for the addresses
3925 have not been reached. Use \-qf-\ (see below) if you want to override this.
3926 .index SMTP||passed connection
3927 .index SMTP||multiple deliveries
3928 .index multiple SMTP deliveries
3929 If the delivery process spawns other processes to deliver other messages down
3930 passed SMTP connections, the queue runner waits for these to finish before
3933 When all the queued messages have been considered, the original queue runner
3934 process terminates. In other words, a single pass is made over the waiting
3935 mail, one message at a time. Use \-q-\ with a time (see below) if you want this
3936 to be repeated periodically.
3938 Exim processes the waiting messages in an unpredictable order. It isn't very
3939 random, but it is likely to be different each time, which is all that matters.
3940 If one particular message screws up a remote MTA, other messages to the same
3941 MTA have a chance of getting through if they get tried first.
3943 It is possible to cause the messages to be processed in lexical message id
3944 order, which is essentially the order in which they arrived, by setting the
3945 \queue@_run@_in@_order\ option, but this is not recommended for normal use.
3947 .option q <<qflags>>
3948 The \-q-\ option may be followed by one or more flag letters that change its
3949 behaviour. They are all optional, but if more than one is present, they must
3950 appear in the correct order. Each flag is described in a separate item below.
3953 .index queue||double scanning
3954 .index queue||routing
3955 .index routing||whole queue before delivery
3956 An option starting with \-qq-\ requests a two-stage queue run. In the first
3957 stage, the queue is scanned as if the \queue@_smtp@_domains\ option matched
3958 every domain. Addresses are routed, local deliveries happen, but no remote
3960 .index hints database||remembering routing
3961 The hints database that remembers which messages are
3962 waiting for specific hosts is updated, as if delivery to those hosts had been
3963 deferred. After this is complete, a second, normal queue scan happens, with
3964 routing and delivery taking place as normal. Messages that are routed to the
3965 same host should mostly be delivered down a single SMTP
3966 .index SMTP||passed connection
3967 .index SMTP||multiple deliveries
3968 .index multiple SMTP deliveries
3969 connection because of the hints that were set up during the first queue scan.
3970 This option may be useful for hosts that are connected to the Internet
3974 .index queue||initial delivery
3975 If the \*i*\ flag is present, the queue runner runs delivery processes only for
3976 those messages that haven't previously been tried. (\*i*\ stands for `initial
3977 delivery'.) This can be helpful if you are putting messages on the queue using
3978 \-odq-\ and want a queue runner just to process the new messages.
3981 .index queue||forcing delivery
3982 .index delivery||forcing in queue run
3983 If one \*f*\ flag is present, a delivery attempt is forced for each non-frozen
3984 message, whereas without \f\ only those non-frozen addresses that have passed
3985 their retry times are tried.
3987 .option q[q][i]ff...
3988 .index frozen messages||forcing delivery
3989 If \*ff*\ is present, a delivery attempt is forced for every message, whether
3992 .option q[q][i][f[f]]l
3993 .index queue||local deliveries only
3994 The \*l*\ (the letter `ell') flag specifies that only local deliveries are to be
3995 done. If a message requires any remote deliveries, it remains on the queue for
3998 .option q <<qflags>>#<<start id>>#<<end id>>
3999 .index queue||delivering specific messages
4000 When scanning the queue, Exim can be made to skip over messages whose ids are
4001 lexically less than a given value by following the \-q-\ option with a starting
4002 message id. For example:
4004 exim -q 0t5C6f-0000c8-00
4006 Messages that arrived earlier than \"0t5C6f-0000c8-00"\ are not inspected. If a
4007 second message id is given, messages whose ids are lexically greater than it
4008 are also skipped. If the same id is given twice, for example,
4010 exim -q 0t5C6f-0000c8-00 0t5C6f-0000c8-00
4012 just one delivery process is started, for that message. This differs from \-M-\
4013 in that retry data is respected, and it also differs from \-Mc-\ in that it
4014 counts as a delivery from a queue run. Note that the selection mechanism does
4015 not affect the order in which the messages are scanned. There are also other
4016 ways of selecting specific sets of messages for delivery in a queue run -- see
4019 .option q <<qflags>><<time>>
4020 .index queue runner||starting periodically
4021 .index periodic queue running
4022 When a time value is present, the \-q-\ option causes Exim to run as a daemon,
4023 starting a queue runner process at intervals specified by the given time value
4024 (whose format is described in section ~~SECTtimeformat). This form of the \-q-\
4025 option is commonly combined with the \-bd-\ option, in which case a single
4026 daemon process handles both functions. A common way of starting up a combined
4027 daemon at system boot time is to use a command such as
4029 /usr/exim/bin/exim -bd -q30m
4031 Such a daemon listens for incoming SMTP calls, and also starts a queue runner
4032 process every 30 minutes.
4034 When a daemon is started by \-q-\ with a time value, but without \-bd-\, no pid
4035 file is written unless one is explicitly requested by the \-oP-\ option.
4037 .option qR <<rsflags>>#<<string>>
4038 This option is synonymous with \-R-\. It is provided for Sendmail
4041 .option qS <<rsflags>>#<<string>>
4042 This option is synonymous with \-S-\.
4044 .option R <<rsflags>>#<<string>>
4045 .index queue runner||for specific recipients
4046 .index delivery||to given domain
4047 .index domain||delivery to
4048 The <<rsflags>> may be empty, in which case the white space before the string
4049 is optional, unless the string is \*f*\, \*ff*\, \*r*\, \*rf*\, or \*rff*\,
4050 which are the possible values for <<rsflags>>. White space is required if
4051 <<rsflags>> is not empty.
4053 This option is similar to \-q-\ with no time value, that is, it causes Exim to
4054 perform a single queue run, except that, when scanning the messages on the
4055 queue, Exim processes only those that have at least one undelivered recipient
4056 address containing the given string, which is checked in a case-independent
4057 way. If the <<rsflags>> start with \*r*\, <<string>> is interpreted as a regular
4058 expression; otherwise it is a literal string.
4060 Once a message is selected, all its addresses are processed. For the first
4061 selected message, Exim overrides any retry information and forces a delivery
4062 attempt for each undelivered address. This means that if delivery of any
4063 address in the first message is successful, any existing retry information is
4064 deleted, and so delivery attempts for that address in subsequently selected
4065 messages (which are processed without forcing) will run. However, if delivery
4066 of any address does not succeed, the retry information is updated, and in
4067 subsequently selected messages, the failing address will be skipped.
4069 If the <<rsflags>> contain \*f*\ or \*ff*\, the delivery forcing applies to all
4070 selected messages, not just the first;
4071 .index frozen messages||forcing delivery
4072 frozen messages are included when \*ff*\ is present.
4074 The \-R-\ option makes it straightforward to initiate delivery of all messages
4075 to a given domain after a host has been down for some time. When the SMTP
4076 command \\ETRN\\ is accepted by its ACL (see chapter ~~CHAPACL), its default
4077 effect is to run Exim with the \-R-\ option, but it can be configured to run an
4078 arbitrary command instead.
4081 This is a documented (for Sendmail) obsolete alternative name for \-f-\.
4083 .index delivery||from given sender
4084 .option S <<rsflags>>#<<string>>
4085 .index queue runner||for specific senders
4086 This option acts like \-R-\ except that it checks the string against each
4087 message's sender instead of against the recipients. If \-R-\ is also set, both
4088 conditions must be met for a message to be selected. If either of the options
4089 has \*f*\ or \*ff*\ in its flags, the associated action is taken.
4091 .option Tqt#<<times>>
4092 This an option that is exclusively for use by the Exim testing suite.
4093 It is not recognized when Exim is run normally. It allows for the setting up
4094 of explicit `queue times' so that various warning/retry features can be
4098 .index recipient||extracting from header lines
4099 .index ::Bcc:: header line
4100 .index ::Cc:: header line
4101 .index ::To:: header line
4102 When Exim is receiving a locally-generated, non-SMTP message on its standard
4103 input, the \-t-\ option causes the recipients of the message to be obtained
4104 from the ::To::, ::Cc::, and ::Bcc:: header lines in the message instead of from
4105 the command arguments. The addresses are extracted before any rewriting takes
4108 .index Sendmail compatibility||\-t-\ option
4109 If the command has any arguments, they specify addresses to which the message
4110 is $it{not} to be delivered. That is, the argument addresses are removed from
4111 the recipients list obtained from the headers. This is compatible with Smail 3
4112 and in accordance with the documented behaviour of several versions of
4113 Sendmail, as described in man pages on a number of operating systems (e.g.
4114 Solaris 8, IRIX 6.5, HP-UX 11). However, some versions of Sendmail $it{add}
4115 argument addresses to those obtained from the headers, and the O'Reilly
4116 Sendmail book documents it that way. Exim can be made to add argument addresses
4117 instead of subtracting them by setting the option
4118 \extract__addresses__remove__arguments\ false.
4120 If a ::Bcc:: header line is present, it is removed from the message unless
4121 there is no ::To:: or ::Cc::, in which case a ::Bcc:: line with no data is
4122 created. This is necessary for conformity with the original RFC 822 standard;
4123 the requirement has been removed in RFC 2822, but that is still very new.
4125 .index \Resent@-\ header lines||with \-t-\
4126 If there are any \Resent@-\ header lines in the message, Exim extracts
4127 recipients from all ::Resent-To::, ::Resent-Cc::, and ::Resent-Bcc:: header
4128 lines instead of from ::To::, ::Cc::, and ::Bcc::. This is for compatibility
4129 with Sendmail and other MTAs. (Prior to release 4.20, Exim gave an error if
4130 \-t-\ was used in conjunction with \Resent@-\ header lines.)
4132 RFC 2822 talks about different sets of \Resent@-\ header lines (for when a
4133 message is resent several times). The RFC also specifies that they should be
4134 added at the front of the message, and separated by ::Received:: lines. It is
4135 not at all clear how \-t-\ should operate in the present of multiple sets,
4136 nor indeed exactly what constitutes a `set'.
4137 In practice, it seems that MUAs do not follow the RFC. The \Resent@-\ lines are
4138 often added at the end of the header, and if a message is resent more than
4139 once, it is common for the original set of \Resent@-\ headers to be renamed as
4140 \X-Resent@-\ when a new set is added. This removes any possible ambiguity.
4143 This option is exactly equivalent to \-t-\ \-i-\. It is provided for
4144 compatibility with Sendmail.
4146 .option tls-on-connect
4147 .index TLS||use without STARTTLS
4148 .index TLS||automatic start
4149 This option is available when Exim is compiled with TLS support. It makes it
4150 possible to support legacy clients that do not support the \\STARTTLS\\
4151 command, but instead expect to start up a TLS session as soon as a connection
4152 to the server is established. These clients use a special port (usually called
4153 the `ssmtp' port) instead of the normal SMTP port 25. The \-tls-on-connect-\
4154 option can be used to run Exim in this way from \*inetd*\, and it can also be
4155 used to run a special daemon that operates in this manner (use \-oX-\ to
4156 specify the port). However, although it is possible to run one daemon that
4157 listens on several ports, it is not possible to have some of them operate one
4158 way and some the other. With only a few clients that need the legacy support, a
4159 convenient approach is to use a daemon for normal SMTP (with or without
4160 \\STARTTLS\\) and \*inetd*\ with \-tls-on-connect-\ for the legacy clients.
4163 .index Sendmail compatibility||\-U-\ option ignored
4164 Sendmail uses this option for `initial message submission', and its
4165 documentation states that in future releases, it may complain about
4166 syntactically invalid messages rather than fixing them when this flag is not
4167 set. Exim ignores this option.
4170 This option causes Exim to write information to the standard error stream,
4171 describing what it is doing. In particular, it shows the log lines for
4172 receiving and delivering a message, and if an SMTP connection is made, the SMTP
4173 dialogue is shown. Some of the log lines shown may not actually be written to
4174 the log if the setting of \log@_selector\ discards them. Any relevant selectors
4175 are shown with each log line. If none are shown, the logging is unconditional.
4178 AIX uses \-x-\ for a private purpose (`mail from a local mail program has
4179 National Language Support extended characters in the body of the mail item').
4180 It sets \-x-\ when calling the MTA from its \mail\ command. Exim ignores this
4191 . ============================================================================
4192 .chapter The Exim run time c
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