Install all the files that comprise the new DocBook way of making the
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1////////////////////////////////////////////////////////////////////////////
2$Cambridge: exim/doc/doc-docbook/spec.ascd,v 1.1 2005/06/16 10:32:31 ph10 Exp $
3
4This is the primary source of the Exim Manual. It is an AsciiDoc document
5that is converted into DocBook XML for subsequent conversion into printing
6and online formats. The markup used herein is traditional AsciiDoc markup,
7with some extras. The markup is summarized in a file called AdMarkup.txt. A
8private AsciiDoc configuration file specifies how the extra markup is to be
9translated into DocBook XML. You MUST use this private AsciiDoc markup if you
10want to get sensible results from processing this document.
11////////////////////////////////////////////////////////////////////////////
12
13
14
15////////////////////////////////////////////////////////////////////////////
16I am abusing the <abstract> DocBook element as the only trivial way of getting
17this information onto the title verso page in the printed renditions. A better
18title page would be a useful improvement. The <abstract> element is removed by
19preprocessing for the HTML renditions, and the whole <docbookinfo> element is
20removed for ascii output formats.
21////////////////////////////////////////////////////////////////////////////
22
23Specification of the Exim Mail Transfer Agent
24=============================================
25:abstract: University of Cambridge Computing Service, New Museums Site, Pembroke Street, Cambridge CB2 3QH, England
26:author: Philip Hazel
27:copyright: University of Cambridge
28:cpyear: 2005
29:date: 13 May 2005
30:doctitleabbrev: The Exim MTA
31:revision: 4.50
32
33
34//////////////////////////////////////////////////////////////////////////////
35***WARNING*** Do not put anything, not even a titleabbrev, setting before
36the first chapter (luckily it does not need one) because if you do, AsciiDoc
37creates an empty <preface> element, which we do not want.
38//////////////////////////////////////////////////////////////////////////////
39
40Introduction
41------------
42
43////////////////////////////////////////////////////////////////////////////
44These are definitions of AsciiDoc "attributes" that are in effect "variables"
45whose values can be substituted. The first makes index entries shorter. The
46second avoids problems with literal asterisks getting tangled up with bold
47emphasis quotes. The others are here for convenience of editing.
48
49***WARNING*** The positioning of these definitions, after the first Chapter
50title, seems to be important. If they are placed earlier, they give rise to
51incorrect XML.
52////////////////////////////////////////////////////////////////////////////
53
54:ACL: access control lists (ACLs)
55:star: *
56:previousversion: 4.40
57:version: 4.50
58
59
60////////////////////////////////////////////////////////////////////////////
61This chunk of literal XML implements index entries of the form "x, see y" and
62"x, see also y". It didn't seem worth inventing AsciiDoc markup for this,
63because is it not something that is likely to change often.
64////////////////////////////////////////////////////////////////////////////
65
66++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
67<indexterm role="concept">
68 <primary>$1, $2, etc.</primary>
69 <see><emphasis>numerical variables</emphasis></see>
70</indexterm>
71<indexterm role="concept">
72 <primary>address</primary>
73 <secondary>rewriting</secondary>
74 <see><emphasis>rewriting</emphasis></see>
75</indexterm>
76<indexterm role="concept">
77 <primary>CR character</primary>
78 <see><emphasis>carriage return</emphasis></see>
79</indexterm>
80<indexterm role="concept">
81 <primary>CRL</primary>
82 <see><emphasis>certificate revocation list</emphasis></see>
83</indexterm>
84<indexterm role="concept">
85 <primary>delivery</primary>
86 <secondary>failure report</secondary>
87 <see><emphasis>bounce message</emphasis></see>
88</indexterm>
89<indexterm role="concept">
90 <primary>dialup</primary>
91 <see><emphasis>intermittently connected hosts</emphasis></see>
92</indexterm>
93<indexterm role="concept">
94 <primary>exiscan</primary>
95 <see><emphasis>content scanning</emphasis></see>
96</indexterm>
97<indexterm role="concept">
98 <primary>failover</primary>
99 <see><emphasis>fallback</emphasis></see>
100</indexterm>
101<indexterm role="concept">
102 <primary>fallover</primary>
103 <see><emphasis>fallback</emphasis></see>
104</indexterm>
105<indexterm role="concept">
106 <primary>filter</primary>
107 <secondary>Sieve</secondary>
108 <see><emphasis>Sieve filter</emphasis></see>
109</indexterm>
110<indexterm role="concept">
111 <primary>ident</primary>
112 <see><emphasis>RFC 1413</emphasis></see>
113</indexterm>
114<indexterm role="concept">
115 <primary>LF character</primary>
116 <see><emphasis>linefeed</emphasis></see>
117</indexterm>
118<indexterm role="concept">
119 <primary>maximum</primary>
120 <see><emphasis>limit</emphasis></see>
121</indexterm>
122<indexterm role="concept">
123 <primary>no_<emphasis>xxx</emphasis></primary>
124 <see>entry for xxx</see>
125</indexterm>
126<indexterm role="concept">
127 <primary>NUL</primary>
128 <see><emphasis>binary zero</emphasis></see>
129</indexterm>
130<indexterm role="concept">
131 <primary>passwd file</primary>
132 <see><emphasis>/etc/passwd</emphasis></see>
133</indexterm>
134<indexterm role="concept">
135 <primary>process id</primary>
136 <see><emphasis>pid</emphasis></see>
137</indexterm>
138<indexterm role="concept">
139 <primary>RBL</primary>
140 <see><emphasis>DNS list</emphasis></see>
141</indexterm>
142<indexterm role="concept">
143 <primary>redirection</primary>
144 <see><emphasis>address redirection</emphasis></see>
145</indexterm>
146<indexterm role="concept">
147 <primary>return path</primary>
148 <seealso><emphasis>envelope sender</emphasis></seealso>
149</indexterm>
150<indexterm role="concept">
151 <primary>scanning</primary>
152 <see><emphasis>content scanning</emphasis></see>
153</indexterm>
154<indexterm role="concept">
155 <primary>SSL</primary>
156 <see><emphasis>TLS</emphasis></see>
157</indexterm>
158<indexterm role="concept">
159 <primary>string</primary>
160 <secondary>expansion</secondary>
161 <see><emphasis>expansion</emphasis></see>
162</indexterm>
163<indexterm role="concept">
164 <primary>top bit</primary>
165 <see><emphasis>8-bit characters</emphasis></see>
166</indexterm>
167<indexterm role="concept">
168 <primary>variables</primary>
169 <see><emphasis>expansion, variables</emphasis></see>
170</indexterm>
171<indexterm role="concept">
172 <primary>zero, binary</primary>
173 <see><emphasis>binary zero</emphasis></see>
174</indexterm>
175++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
176
177
178////////////////////////////////////////////////////////////////////////////
179OK, now we start with the real data for this first chapter.
180////////////////////////////////////////////////////////////////////////////
181
182Exim is a mail transfer agent (MTA) for hosts that are running Unix or
183Unix-like operating systems. It was designed on the assumption that it would be
184run on hosts that are permanently connected to the Internet. However, it can be
185used on intermittently connected hosts with suitable configuration adjustments.
186
187Configuration files currently exist for the following operating systems: AIX,
188BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, FreeBSD, GNU/Hurd, GNU/Linux,
189HI-OSF (Hitachi), HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD, QNX, SCO, SCO
190SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4, Tru64-Unix (formerly
191Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware. Some of these operating
192systems are no longer current and cannot easily be tested, so the configuration
193files may no longer work in practice.
194
195There are also configuration files for compiling Exim in the Cygwin environment
196that can be installed on systems running Windows. However, this document does
197not contain any information about running Exim in the Cygwin environment.
198
199The terms and conditions for the use and distribution of Exim are contained in
200the file _NOTICE_. Exim is distributed under the terms of the GNU General
201Public Licence, a copy of which may be found in the file _LICENCE_.
202
203The use, supply or promotion of Exim for the purpose of sending bulk,
204unsolicited electronic mail is incompatible with the basic aims of the program,
205which revolve around the free provision of a service that enhances the quality
206of personal communications. The author of Exim regards indiscriminate
207mass-mailing as an antisocial, irresponsible abuse of the Internet.
208
209Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
210experience of running and working on the Smail 3 code, I could never have
211contemplated starting to write a new MTA. Many of the ideas and user interfaces
212were originally taken from Smail 3, though the actual code of Exim is entirely
213new, and has developed far beyond the initial concept.
214
215Many people, both in Cambridge and around the world, have contributed to the
216development and the testing of Exim, and to porting it to various operating
217systems. I am grateful to them all. The distribution now contains a file called
218_ACKNOWLEDGMENTS_, in which I have started recording the names of
219contributors.
220
221
222
223Exim documentation
224~~~~~~~~~~~~~~~~~~
225[revisionflag="changed"]
226cindex:[documentation]
227This edition of the Exim specification applies to version {version} of Exim.
228Substantive changes from the {previousversion} edition are marked in some
229renditions of the document; this paragraph is so marked if the rendition is
230capable of showing a change indicator.
231
232This document is very much a reference manual; it is not a tutorial. The reader
233is expected to have some familiarity with the SMTP mail transfer protocol and
234with general Unix system administration. Although there are some discussions
235and examples in places, the information is mostly organized in a way that makes
236it easy to look up, rather than in a natural order for sequential reading.
237Furthermore, the manual aims to cover every aspect of Exim in detail, including
238a number of rarely-used, special-purpose features that are unlikely to be of
239very wide interest.
240
241cindex:[books about Exim]
242An ``easier'' discussion of Exim which provides more in-depth explanatory,
243introductory, and tutorial material can be found in a book entitled
244'The Exim SMTP Mail Server', published by UIT Cambridge
245(*http://www.uit.co.uk/exim-book/[]*).
246
247This book also contains a chapter that gives a general introduction to SMTP and
248Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
249with the latest release of Exim. (Note that the earlier book about Exim,
250published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
251
252cindex:[_doc/NewStuff_]
253cindex:[_doc/ChangeLog_]
254cindex:[change log]
255As the program develops, there may be features in newer versions that have not
256yet made it into this document, which is updated only when the most significant
257digit of the fractional part of the version number changes. Specifications of
258new features that are not yet in this manual are placed in the file
259_doc/NewStuff_ in the Exim distribution.
260
261Some features may be classified as ``experimental''. These may change
262incompatibly while they are developing, or even be withdrawn. For this reason,
263they are not documented in this manual. Information about experimental features
264can be found in the file _doc/experimental.txt_.
265
266All changes to the program (whether new features, bug fixes, or other kinds of
267change) are noted briefly in the file called _doc/ChangeLog_.
268
269cindex:[_doc/spec.txt_]
270This specification itself is available as an ASCII file in _doc/spec.txt_ so
271that it can easily be searched with a text editor. Other files in the _doc_
272directory are:
273
274[frame="none"]
275`--------------------`------------------------------------------
276_OptionLists.txt_ list of all options in alphabetical order
277_dbm.discuss.txt_ discussion about DBM libraries
278_exim.8_ a man page of Exim's command line options
279_experimental.txt_ documentation of experimental features
280_filter.txt_ specification of the filter language
281_pcrepattern.txt_ specification of PCRE regular expressions
282_pcretest.txt_ specification of the PCRE testing program
283_Exim3.upgrade_ upgrade notes from release 2 to release 3
284_Exim4.upgrade_ upgrade notes from release 3 to release 4
285----------------------------------------------------------------
286
287The main specification and the specification of the filtering language are also
288available in other formats (HTML, PostScript, PDF, and Texinfo). Section
289<<SECTavail>> below tells you how to get hold of these.
290
291
292
293FTP and web sites
294~~~~~~~~~~~~~~~~~
295cindex:[web site]
296cindex:[FTP site]
297The primary distribution site for Exim is currently the University of
298Cambridge's FTP site, whose contents are described in 'Where to find the Exim
299distribution' below. In addition, there is a web site and an FTP site at
300%exim.org%. These are now also hosted at the University of Cambridge. The
301%exim.org% site was previously hosted for a number of years by Energis Squared,
302formerly Planet Online Ltd, whose support I gratefully acknowledge.
303
304As well as Exim distribution tar files, the Exim web site contains a number of
305differently formatted versions of the documentation, including the
306cindex:[FAQ] FAQ in both text and HTML formats. The HTML version comes with
307a keyword-in-context index. A recent addition to the online information is the
308cindex:[wiki]
309Exim wiki (*http://www.exim.org/eximwiki/[]*).
310We hope that this will make it easier for Exim users to contribute examples,
311tips, and know-how for the benefit of others.
312
313
314
315Mailing lists
316~~~~~~~~~~~~~
317cindex:[mailing lists,for Exim users]
318The following are the three main Exim mailing lists:
319
320[frame="none"]
321`-------------------------------`----------------------------------------
322'exim-users@exim.org' general discussion list
323'exim-dev@exim.org' discussion of bugs, enhancements, etc.
324'exim-announce@exim.org' moderated, low volume announcements list
325-------------------------------------------------------------------------
326
327You can subscribe to these lists, change your existing subscriptions, and view
328or search the archives via the mailing lists link on the Exim home page. The
329'exim-users' mailing list is also forwarded to
330*http://www.egroups.com/list/exim-users[]*, an archiving system with searching
331capabilities.
332
333
334Exim training
335~~~~~~~~~~~~~
336cindex:[training courses]
337From time to time (approximately annually at the time of writing),
338lecture-based training courses are run by the author of Exim in Cambridge, UK.
339Details can be found on the web site
340*http://www-tus.csx.cam.ac.uk/courses/exim/[]*.
341
342
343Bug reports
344~~~~~~~~~~~
345cindex:[bug reports]
346cindex:[reporting bugs]
347Reports of obvious bugs should be emailed to 'bugs@exim.org'. However, if
348you are unsure whether some behaviour is a bug or not, the best thing to do is
349to post a message to the 'exim-users' mailing list and have it discussed.
350
351
352
353[[SECTavail]]
354Where to find the Exim distribution
355~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
356cindex:[FTP site]
357cindex:[distribution,ftp site]
358The master ftp site for the Exim distribution is
359
360&&&
361*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim[]*
362&&&
363
364This is mirrored by
365
366&&&
367*ftp://ftp.exim.org/pub/exim[]*
368&&&
369
370The file references that follow are relative to the _exim_ directories at these
371sites. There are now quite a number of independent mirror sites around the
372world. Those that I know about are listed in the file called _Mirrors_.
373
374Within the _exim_ directory there are subdirectories called _exim3_ (for
375previous Exim 3 distributions), _exim4_ (for the latest Exim 4
376distributions), and _Testing_ for testing versions. In the _exim4_
377subdirectory, the current release can always be found in files called
378
379&&&
380_exim-n.nn.tar.gz_
381_exim-n.nn.tar.bz2_
382&&&
383
384where 'n.nn' is the highest such version number in the directory. The two
385files contain identical data; the only difference is the type of compression.
386The _.bz2_ file is usually a lot smaller than the _.gz_ file.
387
388cindex:[distribution,signing details]
389cindex:[distribution,public key]
390cindex:[public key for signed distribution]
391The distributions are currently signed with Philip Hazel's GPG key. The
392corresponding public key is available from a number of keyservers, and there is
393also a copy in the file _Public-Key_. The signatures for the tar bundles are
394in:
395
396&&&
397_exim-n.nn.tar.gz.sig_
398_exim-n.nn.tar.bz2.sig_
399&&&
400
401For each released version, the log of changes is made separately available in a
402separate file in the directory _ChangeLogs_ so that it is possible to
403find out what has changed without having to download the entire distribution.
404
405cindex:[documentation,available formats]
406The main distribution contains ASCII versions of this specification and other
407documentation; other formats of the documents are available in separate files
408inside the _exim4_ directory of the FTP site:
409
410&&&
411_exim-html-n.nn.tar.gz_
412_exim-pdf-n.nn.tar.gz_
413_exim-postscript-n.nn.tar.gz_
414_exim-texinfo-n.nn.tar.gz_
415&&&
416
417These tar files contain only the _doc_ directory, not the complete
418distribution, and are also available in _.bz2_ as well as _.gz_ forms.
419cindex:[FAQ]
420The FAQ is available for downloading in two different formats in these files:
421
422&&&
423_exim4/FAQ.txt.gz_
424_exim4/FAQ.html.tar.gz_
425&&&
426
427The first of these is a single ASCII file that can be searched with a text
428editor. The second is a directory of HTML files, normally accessed by starting
429at _index.html_. The HTML version of the FAQ (which is also included in the
430HTML documentation tarbundle) includes a keyword-in-context index, which is
431often the most convenient way of finding your way around.
432
433
434Wish list
435~~~~~~~~~
436cindex:[wish list]
437A wish list is maintained, containing ideas for new features that have been
438submitted. From time to time the file is exported to the ftp site into the file
439_exim4/WishList_. Items are removed from the list if they get implemented.
440
441
442
443Contributed material
444~~~~~~~~~~~~~~~~~~~~
445cindex:[contributed material]
446At the ftp site, there is a directory called _Contrib_ that contains
447miscellaneous files contributed to the Exim community by Exim users. There is
448also a collection of contributed configuration examples in
449_exim4/config.samples.tar.gz_. These samples are referenced from the FAQ.
450
451
452
453Limitations
454~~~~~~~~~~~
455- cindex:[limitations of Exim]
456Exim is designed for use as an Internet MTA, and therefore handles addresses
457in RFC 2822 domain format only.
458cindex:[bang paths,not handled by Exim]
459It cannot handle UUCP ``bang paths'', though simple two-component bang paths can
460be converted by a straightforward rewriting configuration. This restriction
461does not prevent Exim from being interfaced to UUCP as a transport mechanism,
462provided that domain addresses are used.
463
464- cindex:[domainless addresses]
465cindex:[address,without domain]
466Exim insists that every address it handles has a domain attached. For incoming
467local messages, domainless addresses are automatically qualified with a
468configured domain value. Configuration options specify from which remote
469systems unqualified addresses are acceptable. These are then qualified on
470arrival.
471
472- cindex:[transport,external]
473cindex:[external transports]
474The only external transport currently implemented is an SMTP transport over a
475TCP/IP network (using sockets, including support for IPv6). However, a pipe
476transport is available, and there are facilities for writing messages to files
477and pipes, optionally in 'batched SMTP' format; these facilities can be used
478to send messages to some other transport mechanism such as UUCP, provided it
479can handle domain-style addresses. Batched SMTP input is also catered for.
480
481- Exim is not designed for storing mail for dial-in hosts. When the volumes of
482such mail are large, it is better to get the messages ``delivered'' into files
483(that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
484other means.
485
486- Although Exim does have basic facilities for scanning incoming messages, these
487are not comprehensive enough to do full virus or spam scanning. Such operations
488are best carried out using additional specialized software packages. If you
489compile Exim with the content-scanning extension, straightforward interfaces to
490a number of common scanners are provided.
491
492
493
494
495
496Run time configuration
497~~~~~~~~~~~~~~~~~~~~~~
498Exim's run time configuration is held in a single text file that is divided
499into a number of sections. The entries in this file consist of keywords and
500values, in the style of Smail 3 configuration files. A default configuration
501file which is suitable for simple online installations is provided in the
502distribution, and is described in chapter <<CHAPdefconfil>> below.
503
504
505
506Calling interface
507~~~~~~~~~~~~~~~~~
508cindex:[Sendmail compatibility,command line interface]
509Like many MTAs, Exim has adopted the Sendmail command line interface so that it
510can be a straight replacement for _/usr/lib/sendmail_ or
511_/usr/sbin/sendmail_ when sending mail, but you do not need to know anything
512about Sendmail in order to run Exim. For actions other than sending messages,
513Sendmail-compatible options also exist, but those that produce output (for
514example, %-bp%, which lists the messages on the queue) do so in Exim's own
515format. There are also some additional options that are compatible with Smail
5163, and some further options that are new to Exim. Chapter <<CHAPcommandline>>
517documents all Exim's command line options. This information is automatically
518made into the man page that forms part of the Exim distribution.
519
520Control of messages on the queue can be done via certain privileged command
521line options. There is also an optional monitor program called 'eximon', which
522displays current information in an X window, and which contains a menu
523interface to Exim's command line administration options.
524
525
526
527Terminology
528~~~~~~~~~~~
529cindex:[terminology definitions]
530cindex:[body of message,definition of]
531The 'body' of a message is the actual data that the sender wants to transmit.
532It is the last part of a message, and is separated from the 'header' (see
533below) by a blank line.
534
535cindex:[bounce message,definition of]
536When a message cannot be delivered, it is normally returned to the sender in a
537delivery failure message or a ``non-delivery report'' (NDR). The term 'bounce'
538is commonly used for this action, and the error reports are often called
539'bounce messages'. This is a convenient shorthand for ``delivery failure error
540report''. Such messages have an empty sender address in the message's
541'envelope' (see below) to ensure that they cannot themselves give rise to
542further bounce messages.
543
544The term 'default' appears frequently in this manual. It is used to qualify a
545value which is used in the absence of any setting in the configuration. It may
546also qualify an action which is taken unless a configuration setting specifies
547otherwise.
548
549The term 'defer' is used when the delivery of a message to a specific
550destination cannot immediately take place for some reason (a remote host may be
551down, or a user's local mailbox may be full). Such deliveries are 'deferred'
552until a later time.
553
554The word 'domain' is sometimes used to mean all but the first component of a
555host's name. It is 'not' used in that sense here, where it normally
556refers to the part of an email address following the @ sign.
557
558cindex:[envelope, definition of]
559cindex:[sender,definition of]
560A message in transit has an associated 'envelope', as well as a header and a
561body. The envelope contains a sender address (to which bounce messages should
562be delivered), and any number of recipient addresses. References to the
563sender or the recipients of a message usually mean the addresses in the
564envelope. An MTA uses these addresses for delivery, and for returning bounce
565messages, not the addresses that appear in the header lines.
566
567cindex:[message header, definition of]
568cindex:[header section,definition of]
569The 'header' of a message is the first part of a message's text, consisting
570of a number of lines, each of which has a name such as 'From:', 'To:',
571'Subject:', etc. Long header lines can be split over several text lines by
572indenting the continuations. The header is separated from the body by a blank
573line.
574
575cindex:[local part,definition of]
576cindex:[domain,definition of]
577The term 'local part', which is taken from RFC 2822, is used to refer to that
578part of an email address that precedes the @ sign. The part that follows the
579@ sign is called the 'domain' or 'mail domain'.
580
581cindex:[local delivery,definition of]
582cindex:[remote delivery, definition of]
583The terms 'local delivery' and 'remote delivery' are used to distinguish
584delivery to a file or a pipe on the local host from delivery by SMTP over
585TCP/IP to a remote host.
586
587cindex:[return path,definition of]
588'Return path' is another name that is used for the sender address in a
589message's envelope.
590
591cindex:[queue,definition of]
592The term 'queue' is used to refer to the set of messages awaiting delivery,
593because this term is in widespread use in the context of MTAs. However, in
594Exim's case the reality is more like a pool than a queue, because there is
595normally no ordering of waiting messages.
596
597cindex:[queue runner,definition of]
598The term 'queue runner' is used to describe a process that scans the queue
599and attempts to deliver those messages whose retry times have come. This term
600is used by other MTAs, and also relates to the command %runq%, but in Exim
601the waiting messages are normally processed in an unpredictable order.
602
603cindex:[spool directory,definition of]
604The term 'spool directory' is used for a directory in which Exim keeps the
605messages on its queue -- that is, those that it is in the process of
606delivering. This should not be confused with the directory in which local
607mailboxes are stored, which is called a ``spool directory'' by some people. In
608the Exim documentation, ``spool'' is always used in the first sense.
609
610
611
612
613
614
615////////////////////////////////////////////////////////////////////////////
616////////////////////////////////////////////////////////////////////////////
617
618Incorporated code
619-----------------
620cindex:[incorporated code]
621cindex:[regular expressions,library]
622cindex:[PCRE]
623A number of pieces of external code are included in the Exim distribution.
624
625- Regular expressions are supported in the main Exim program and in the Exim
626monitor using the freely-distributable PCRE library, copyright (c) University
627of Cambridge. The source is distributed in the directory _src/pcre_. However,
628this is a cut-down version of PCRE. If you want to use the PCRE library in
629other programs, you should obtain and install the full version from
630*ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre[]*.
631
632- cindex:[cdb,acknowledgement]
633Support for the cdb (Constant DataBase) lookup method is provided by code
634contributed by Nigel Metheringham of (at the time he contributed it) Planet
635Online Ltd. which contains the following statements:
636+
637Copyright (c) 1998 Nigel Metheringham, Planet Online Ltd
638+
639This program is free software; you can redistribute it and/or modify it under
640the terms of the GNU General Public License as published by the Free Software
641Foundation; either version 2 of the License, or (at your option) any later
642version.
643+
644This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
645the spec and sample code for cdb can be obtained from
646*http://www.pobox.com/{tl}djb/cdb.html[]*. This implementation borrows some code
647from Dan Bernstein's implementation (which has no license restrictions applied
648to it).
649+
650The implementation is completely contained within the code of Exim.
651It does not link against an external cdb library.
652
653- cindex:[SPA authentication]
654cindex:[Samba project]
655cindex:[Microsoft Secure Password Authentication]
656Client support for Microsoft's 'Secure Password Authentication' is provided
657by code contributed by Marc Prud'hommeaux. Server support was contributed by
658Tom Kistner. This includes code taken from the Samba project, which is released
659under the Gnu GPL.
660
661- cindex:[Cyrus]
662cindex:['pwcheck' daemon]
663cindex:['pwauthd' daemon]
664Support for calling the Cyrus 'pwcheck' and 'saslauthd' daemons is provided
665by code taken from the Cyrus-SASL library and adapted by Alexander S.
666Sabourenkov. The permission notice appears below, in accordance with the
667conditions expressed therein.
668+
669Copyright (c) 2001 Carnegie Mellon University. All rights reserved.
670+
671Redistribution and use in source and binary forms, with or without
672modification, are permitted provided that the following conditions
673are met:
674+
675. Redistributions of source code must retain the above copyright
676notice, this list of conditions and the following disclaimer.
677
678. Redistributions in binary form must reproduce the above copyright
679notice, this list of conditions and the following disclaimer in
680the documentation and/or other materials provided with the
681distribution.
682
683. The name ``Carnegie Mellon University'' must not be used to
684endorse or promote products derived from this software without
685prior written permission. For permission or any other legal
686details, please contact
687+
688&&&
689Office of Technology Transfer
690Carnegie Mellon University
6915000 Forbes Avenue
692Pittsburgh, PA 15213-3890
693(412) 268-4387, fax: (412) 268-7395
694tech-transfer@andrew.cmu.edu
695&&&
696
697. Redistributions of any form whatsoever must retain the following
698acknowledgment:
699+
700'This product includes software developed by Computing Services
701at Carnegie Mellon University (*http://www.cmu.edu/computing/[]*).'
702+
703CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
704THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
705AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
706FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
707WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
708AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
709OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
710
711. cindex:[monitor]
712cindex:[X-windows]
713cindex:[Athena]
714The Exim Monitor program, which is an X-Window application, includes
715modified versions of the Athena StripChart and TextPop widgets.
716This code is copyright by DEC and MIT, and their permission notice appears
717below, in accordance with the conditions expressed therein.
718+
719Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
720and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
721+
722All Rights Reserved
723+
724Permission to use, copy, modify, and distribute this software and its
725documentation for any purpose and without fee is hereby granted,
726provided that the above copyright notice appear in all copies and that
727both that copyright notice and this permission notice appear in
728supporting documentation, and that the names of Digital or MIT not be
729used in advertising or publicity pertaining to distribution of the
730software without specific, written prior permission.
731+
732DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
733ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
734DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
735ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
736WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
737ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
738SOFTWARE.
739
740. Many people have contributed code fragments, some large, some small, that were
741not covered by any specific licence requirements. It is assumed that the
742contributors are happy to see their code incoporated into Exim under the GPL.
743
744
745
746
747
748////////////////////////////////////////////////////////////////////////////
749////////////////////////////////////////////////////////////////////////////
750
751[titleabbrev="Receiving and delivering mail"]
752How Exim receives and delivers mail
753-----------------------------------
754
755
756Overall philosophy
757~~~~~~~~~~~~~~~~~~
758cindex:[design philosophy]
759Exim is designed to work efficiently on systems that are permanently connected
760to the Internet and are handling a general mix of mail. In such circumstances,
761most messages can be delivered immediately. Consequently, Exim does not
762maintain independent queues of messages for specific domains or hosts, though
763it does try to send several messages in a single SMTP connection after a host
764has been down, and it also maintains per-host retry information.
765
766
767
768Policy control
769~~~~~~~~~~~~~~
770cindex:[policy control,overview]
771Policy controls are now an important feature of MTAs that are connected to the
772Internet. Perhaps their most important job is to stop MTAs being abused as
773``open relays'' by misguided individuals who send out vast amounts of unsolicited
774junk, and want to disguise its source. Exim provides flexible facilities for
775specifying policy controls on incoming mail:
776
777- cindex:[{ACL},introduction]
778Exim 4 (unlike previous versions of Exim) implements policy controls on
779incoming mail by means of 'Access Control Lists' (ACLs). Each list is a
780series of statements that may either grant or deny access. ACLs can be used at
781several places in the SMTP dialogue while receiving a message from a remote
782host. However, the most common places are after each RCPT command, and at
783the very end of the message. The sysadmin can specify conditions for accepting
784or rejecting individual recipients or the entire message, respectively, at
785these two points (see chapter <<CHAPACL>>). Denial of access results in an SMTP
786error code.
787
788- An ACL is also available for locally generated, non-SMTP messages. In this
789case, the only available actions are to accept or deny the entire message.
790
791- When Exim is compiled with the content-scanning extension, facilities are
792provided in the ACL mechanism for passing the message to external virus and/or
793spam scanning software. The result of such a scan is passed back to the ACL,
794which can then use it to decide what to do with the message.
795
796- When a message has been received, either from a remote host or from the local
797host, but before the final acknowledgement has been sent, a locally supplied C
798function called 'local_scan()' can be run to inspect the message and decide
799whether to accept it or not (see chapter <<CHAPlocalscan>>). If the message is
800accepted, the list of recipients can be modified by the function.
801
802- Using the 'local_scan()' mechanism is another way of calling external
803scanner software. The %SA-Exim% add-on package works this way. It does not
804require Exim to be compiled with the content-scanning extension.
805
806- After a message has been accepted, a further checking mechanism is available in
807the form of the 'system filter' (see chapter <<CHAPsystemfilter>>). This runs
808at the start of every delivery process.
809
810
811
812User filters
813~~~~~~~~~~~~
814cindex:[filter,introduction]
815cindex:[Sieve filter]
816In a conventional Exim configuration, users are able to run private filters by
817setting up appropriate _.forward_ files in their home directories. See
818chapter <<CHAPredirect>> (about the ^redirect^ router) for the configuration
819needed to support this, and the separate document entitled 'Exim's interfaces
820to mail filtering' for user details. Two different kinds of filtering are
821available:
822
823- Sieve filters are written in the standard filtering language that is defined
824by RFC 3028.
825
826- Exim filters are written in a syntax that is unique to Exim, but which is more
827powerful than Sieve, which it pre-dates.
828
829User filters are run as part of the routing process, described below.
830
831
832
833[[SECTmessiden]]
834Message identification
835~~~~~~~~~~~~~~~~~~~~~~
836cindex:[message ids, details of format]
837cindex:[format,of message id]
838cindex:[id of message]
839cindex:[base62]
840cindex:[base36]
841cindex:[Darwin]
842cindex:[Cygwin]
843Every message handled by Exim is given a 'message id' which is sixteen
844characters long. It is divided into three parts, separated by hyphens, for
845example `16VDhn-0001bo-D3`. Each part is a sequence of letters and digits,
846normally encoding numbers in base 62. However, in the Darwin operating
847system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
848(avoiding the use of lower case letters) is used instead, because the message
849id is used to construct file names, and the names of files in those systems are
850not case-sensitive.
851
852cindex:[pid (process id),re-use of]
853The detail of the contents of the message id have changed as Exim has evolved.
854Earlier versions relied on the operating system not re-using a process id (pid)
855within one second. On modern operating systems, this assumption can no longer
856be made, so the algorithm had to be changed. To retain backward compatibility,
857the format of the message id was retained, which is why the following rules are
858somewhat eccentric:
859
860- The first six characters of the message id are the time at which the message
861started to be received, to a granularity of one second. That is, this field
862contains the number of seconds since the start of the epoch (the normal Unix
863way of representing the date and time of day).
864
865- After the first hyphen, the next six characters are the id of the process that
866received the message.
867
868- There are two different possibilities for the final two characters:
869
870. cindex:[%localhost_number%]
871If %localhost_number% is not set, this value is the fractional part of the
872time of reception, normally in units of 1/2000 of a second, but for systems
873that must use base 36 instead of base 62 (because of case-insensitive file
874systems), the units are 1/1000 of a second.
875
876. If %localhost_number% is set, it is multiplied by 200 (100) and added to
877the fractional part of the time, which in this case is in units of 1/200
878(1/100) of a second.
879
880After a message has been received, Exim waits for the clock to tick at the
881appropriate resolution before proceeding, so that if another message is
882received by the same process, or by another process with the same (re-used)
883pid, it is guaranteed that the time will be different. In most cases, the clock
884will already have ticked while the message was being received.
885
886
887Receiving mail
888~~~~~~~~~~~~~~
889cindex:[receiving mail]
890cindex:[message,reception]
891The only way Exim can receive mail from a remote host is using SMTP over
892TCP/IP, in which case the sender and recipient addresses are tranferred using
893SMTP commands. However, from a locally running process (such as a user's MUA),
894there are several possibilities:
895
896- If the process runs Exim with the %-bm% option, the message is read
897non-interactively (usually via a pipe), with the recipients taken from the
898command line, or from the body of the message if %-t% is also used.
899
900- If the process runs Exim with the %-bS% option, the message is also read
901non-interactively, but in this case the recipients are listed at the start of
902the message in a series of SMTP RCPT commands, terminated by a DATA
903command. This is so-called ``batch SMTP'' format,
904but it isn't really SMTP. The SMTP commands are just another way of passing
905envelope addresses in a non-interactive submission.
906
907- If the process runs Exim with the %-bs% option, the message is read
908interactively, using the SMTP protocol. A two-way pipe is normally used for
909passing data between the local process and the Exim process.
910This is ``real'' SMTP and is handled in the same way as SMTP over TCP/IP. For
911example, the ACLs for SMTP commands are used for this form of submission.
912
913- A local process may also make a TCP/IP call to the host's loopback address
914(127.0.0.1) or any other of its IP addresses. When receiving messages, Exim
915does not treat the loopback address specially. It treats all such connections
916in the same way as connections from other hosts.
917
918
919cindex:[message sender, constructed by Exim]
920cindex:[sender,constructed by Exim]
921In the three cases that do not involve TCP/IP, the sender address is
922constructed from the login name of the user that called Exim and a default
923qualification domain (which can be set by the %qualify_domain% configuration
924option). For local or batch SMTP, a sender address that is passed using the
925SMTP MAIL command is ignored. However, the system administrator may allow
926certain users (``trusted users'') to specify a different sender address
927unconditionally, or all users to specify certain forms of different sender
928address. The %-f% option or the SMTP MAIL command is used to specify these
929different addresses. See section <<SECTtrustedadmin>> for details of trusted
930users, and the %untrusted_set_sender% option for a way of allowing untrusted
931users to change sender addresses.
932
933Messages received by either of the non-interactive mechanisms are subject to
934checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
935(either over TCP/IP, or interacting with a local process) can be checked by a
936number of ACLs that operate at different times during the SMTP session. Either
937individual recipients, or the entire message, can be rejected if local policy
938requirements are not met. The 'local_scan()' function (see chapter
939<<CHAPlocalscan>>) is run for all incoming messages.
940
941Exim can be configured not to start a delivery process when a message is
942received; this can be unconditional, or depend on the number of incoming SMTP
943connections or the system load. In these situations, new messages wait on the
944queue until a queue runner process picks them up. However, in standard
945configurations under normal conditions, delivery is started as soon as a
946message is received.
947
948
949
950
951
952Handling an incoming message
953~~~~~~~~~~~~~~~~~~~~~~~~~~~~
954cindex:[spool directory,files that hold a message]
955cindex:[file,how a message is held]
956When Exim accepts a message, it writes two files in its spool directory. The
957first contains the envelope information, the current status of the message, and
958the header lines, and the second contains the body of the message. The names of
959the two spool files consist of the message id, followed by `-H` for the
960file containing the envelope and header, and `-D` for the data file.
961
962cindex:[spool directory,_input_ sub-directory]
963By default all these message files are held in a single directory called
964_input_ inside the general Exim spool directory. Some operating systems do
965not perform very well if the number of files in a directory gets very large; to
966improve performance in such cases, the %split_spool_directory% option can be
967used. This causes Exim to split up the input files into 62 sub-directories
968whose names are single letters or digits.
969
970The envelope information consists of the address of the message's sender and
971the addresses of the recipients. This information is entirely separate from
972any addresses contained in the header lines. The status of the message includes
973a list of recipients who have already received the message. The format of the
974first spool file is described in chapter <<CHAPspool>>.
975
976cindex:[rewriting,addresses]
977Address rewriting that is specified in the rewrite section of the configuration
978(see chapter <<CHAPrewrite>>) is done once and for all on incoming addresses,
979both in the header lines and the envelope, at the time the message is accepted.
980If during the course of delivery additional addresses are generated (for
981example, via aliasing), these new addresses are rewritten as soon as they are
982generated. At the time a message is actually delivered (transported) further
983rewriting can take place; because this is a transport option, it can be
984different for different forms of delivery. It is also possible to specify the
985addition or removal of certain header lines at the time the message is
986delivered (see chapters <<CHAProutergeneric>> and <<CHAPtransportgeneric>>).
987
988
989
990Life of a message
991~~~~~~~~~~~~~~~~~
992cindex:[message,life of]
993cindex:[message,frozen]
994A message remains in the spool directory until it is completely delivered to
995its recipients or to an error address, or until it is deleted by an
996administrator or by the user who originally created it. In cases when delivery
997cannot proceed -- for example, when a message can neither be delivered to its
998recipients nor returned to its sender, the message is marked ``frozen'' on the
999spool, and no more deliveries are attempted.
1000
1001cindex:[frozen messages,thawing]
1002cindex:[message,thawing frozen]
1003An administrator can ``thaw'' such messages when the problem has been corrected,
1004and can also freeze individual messages by hand if necessary. In addition, an
1005administrator can force a delivery error, causing a bounce message to be sent.
1006
1007cindex:[%auto_thaw%]
1008There is an option called %auto_thaw%, which can be used to cause Exim to
1009retry frozen messages after a certain time. When this is set, no message will
1010remain on the queue for ever, because the delivery timeout will eventually be
1011reached. Delivery failure reports (bounce messages) that reach this timeout are
1012discarded.
1013
1014cindex:[%timeout_frozen_after%]
1015There is also an option called %timeout_frozen_after%, which discards frozen
1016messages after a certain time.
1017
1018cindex:[message,log file for]
1019cindex:[log,file for each message]
1020While Exim is working on a message, it writes information about each delivery
1021attempt to the main log file. This includes successful, unsuccessful, and
1022delayed deliveries for each recipient (see chapter <<CHAPlog>>). The log lines
1023are also written to a separate 'message log' file for each message. These
1024logs are solely for the benefit of the administrator, and are normally deleted
1025along with the spool files when processing of a message is complete.
1026The use of individual message logs can be disabled by setting
1027%no_message_logs%; this might give an improvement in performance on very
1028busy systems.
1029
1030cindex:[journal file]
1031cindex:[file,journal]
1032All the information Exim itself needs to set up a delivery is kept in the first
1033spool file, along with the header lines. When a successful delivery occurs, the
1034address is immediately written at the end of a journal file, whose name is the
1035message id followed by `-J`. At the end of a delivery run, if there are some
1036addresses left to be tried again later, the first spool file (the `-H` file)
1037is updated to indicate which these are, and the journal file is then deleted.
1038Updating the spool file is done by writing a new file and renaming it, to
1039minimize the possibility of data loss.
1040
1041Should the system or the program crash after a successful delivery but before
1042the spool file has been updated, the journal is left lying around. The next
1043time Exim attempts to deliver the message, it reads the journal file and
1044updates the spool file before proceeding. This minimizes the chances of double
1045deliveries caused by crashes.
1046
1047
1048
1049[[SECTprocaddress]]
1050Processing an address for delivery
1051~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1052cindex:[drivers,definition of]
1053cindex:[router,definition of]
1054cindex:[transport,definition of]
1055The main delivery processing elements of Exim are called 'routers' and
1056'transports', and collectively these are known as 'drivers'. Code for a
1057number of them is provided in the source distribution, and compile-time options
1058specify which ones are included in the binary. Run time options specify which
1059ones are actually used for delivering messages.
1060
1061cindex:[drivers,instance definition]
1062Each driver that is specified in the run time configuration is an 'instance'
1063of that particular driver type. Multiple instances are allowed; for example,
1064you can set up several different ^smtp^ transports, each with different
1065option values that might specify different ports or different timeouts. Each
1066instance has its own identifying name. In what follows we will normally use the
1067instance name when discussing one particular instance (that is, one specific
1068configuration of the driver), and the generic driver name when discussing
1069the driver's features in general.
1070
1071A 'router' is a driver that operates on an address, either determining how
1072its delivery should happen, by routing it to a specific transport, or
1073converting the address into one or more new addresses (for example, via an
1074alias file). A router may also explicitly choose to fail an address, causing it
1075to be bounced.
1076
1077A 'transport' is a driver that transmits a copy of the message from Exim's
1078spool to some destination. There are two kinds of transport: for a 'local'
1079transport, the destination is a file or a pipe on the local host, whereas for a
1080'remote' transport the destination is some other host. A message is passed
1081to a specific transport as a result of successful routing. If a message has
1082several recipients, it may be passed to a number of different transports.
1083
1084cindex:[preconditions,definition of]
1085An address is processed by passing it to each configured router instance in
1086turn, subject to certain preconditions, until a router accepts the address or
1087specifies that it should be bounced. We will describe this process in more
1088detail shortly. As a simple example, the diagram below illustrates how each
1089recipient address in a message is processed in a small configuration of three
1090routers that are configured in various ways.
1091
1092To make this a more concrete example, we'll describe it in terms of some actual
1093routers, but remember, this is only an example. You can configure Exim's
1094routers in many different ways, and there may be any number of routers in a
1095configuration.
1096
1097The first router that is specified in a configuration is often one that handles
1098addresses in domains that are not recognized specially by the local host. These
1099are typically addresses for arbitrary domains on the Internet. A precondition
1100is set up which looks for the special domains known to the host (for example,
1101its own domain name), and the router is run for addresses that do 'not'
1102match. Typically, this is a router that looks up domains in the DNS in order to
1103find the hosts to which this address routes. If it succeeds, the address is
1104queued for a suitable SMTP transport; if it does not succeed, the router is
1105configured to fail the address.
1106
1107///
1108The example pictured could be a configuration of this type. The second and
1109third routers can only be run for addresses for which the preconditions for
1110the first router are not met. If one of these preconditions checks the
1111domain, the second and third routers are run only for domains that are somehow
1112special to the local host.
1113///
1114
1115The second router does redirection -- also known as aliasing and forwarding.
1116When it generates one or more new addresses from the original, each of them is
1117routed independently from the start. Otherwise, the router may cause an address
1118to fail, or it may simply decline to handle the address, in which case the
1119address is passed to the next router.
1120
1121The final router in many configurations is one that checks to see if the
1122address belongs to a local mailbox. The precondition may involve a check to
1123see if the local part is the name of a login account, or it may look up the
1124local part in a file or a database. If its preconditions are not met, or if
1125the router declines, we have reached the end of the routers. When this happens,
1126the address is bounced.
1127
1128
1129
1130Processing an address for verification
1131~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1132cindex:[router,for verification]
1133cindex:[verifying address, overview]
1134As well as being used to decide how to deliver to an address, Exim's routers
1135are also used for 'address verification'. Verification can be requested as
1136one of the checks to be performed in an ACL for incoming messages, on both
1137sender and recipient addresses, and it can be tested using the %-bv% and
1138%-bvs% command line options.
1139
1140When an address is being verified, the routers are run in ``verify mode''. This
1141does not affect the way the routers work, but it is a state that can be
1142detected. By this means, a router can be skipped or made to behave differently
1143when verifying. A common example is a configuration in which the first router
1144sends all messages to a message-scanning program, unless they have been
1145previously scanned. Thus, the first router accepts all addresses without any
1146checking, making it useless for verifying. Normally, the %no_verify% option
1147would be set for such a router, causing it to be skipped in verify mode.
1148
1149
1150
1151
1152[[SECTrunindrou]]
1153Running an individual router
1154~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1155cindex:[router,running details]
1156cindex:[preconditions,checking]
1157cindex:[router,result of running]
1158As explained in the example above, a number of preconditions are checked before
1159running a router. If any are not met, the router is skipped, and the address is
1160passed to the next router. When all the preconditions on a router 'are' met,
1161the router is run. What happens next depends on the outcome, which is one of
1162the following:
1163
1164- 'accept': The router accepts the address, and either queues it for a
1165transport, or generates one or more ``child'' addresses. Processing the original
1166address ceases,
1167cindex:[%unseen% option]
1168unless the %unseen% option is set on the router. This option
1169can be used to set up multiple deliveries with different routing (for example,
1170for keeping archive copies of messages). When %unseen% is set, the address is
1171passed to the next router. Normally, however, an 'accept' return marks the
1172end of routing.
1173+
1174cindex:[case of local parts]
1175cindex:[address duplicate, discarding]
1176If child addresses are generated, Exim checks to see whether they are
1177duplicates of any existing recipient addresses. During this check, local parts
1178are treated as case-sensitive. Duplicate addresses are discarded. Each of the
1179remaining child addresses is then processed independently, starting with the
1180first router by default. It is possible to change this by setting the
1181%redirect_router% option to specify which router to start at for child
1182addresses. Unlike %pass_router% (see below) the router specified by
1183%redirect_router% may be anywhere in the router configuration.
1184
1185- 'pass': The router recognizes the address, but cannot handle it itself. It
1186requests that the address be passed to another router. By default the address
1187is passed to the next router, but this can be changed by setting the
1188%pass_router% option. However, (unlike %redirect_router%) the named router
1189must be below the current router (to avoid loops).
1190
1191- 'decline': The router declines to accept the address because it does not
1192recognize it at all. By default, the address is passed to the next router, but
1193this can be prevented by setting the %no_more% option. When %no_more% is set,
1194all the remaining routers are skipped.
1195
1196- 'fail': The router determines that the address should fail, and queues it for
1197the generation of a bounce message. There is no further processing of the
1198original address unless %unseen% is set on the router.
1199
1200- 'defer': The router cannot handle the address at the present time. (A database
1201may be offline, or a DNS lookup may have timed out.) No further processing of
1202the address happens in this delivery attempt. It is tried again next time the
1203message is considered for delivery.
1204
1205- 'error': There is some error in the router (for example, a syntax error in
1206its configuration). The action is as for defer.
1207
1208If an address reaches the end of the routers without having been accepted by
1209any of them, it is bounced as unrouteable.
1210The default error message in this situation is ``unrouteable address'', but you
1211can set your own message by making use of the %cannot_route_message% option.
1212This can be set for any router; the value from the last router that ``saw''
1213the address is used.
1214
1215Sometimes while routing you want to fail a delivery when some conditions are
1216met but others are not, instead of passing the address on for further routing.
1217You can do this by having a second router that explicitly fails the delivery
1218when the relevant conditions are met. The ^redirect^ router has a ``fail''
1219facility for this purpose.
1220
1221
1222
1223
1224[[SECTrouprecon]]
1225Router preconditions
1226~~~~~~~~~~~~~~~~~~~~
1227cindex:[router preconditions, order of processing]
1228cindex:[preconditions,order of processing]
1229The preconditions that are tested for each router are listed below, in the
1230order in which they are tested. The individual configuration options are
1231described in more detail in chapter <<CHAProutergeneric>>.
1232
1233- The %local_part_prefix% and %local_part_suffix% options can specify that
1234the local parts handled by the router may or must have certain prefixes and/or
1235suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1236skipped. These conditions are tested first. When an affix is present, it is
1237removed from the local part before further processing, including the evaluation
1238of any other conditions.
1239
1240- Routers can be designated for use only when not verifying an address, that is,
1241only when routing it for delivery (or testing its delivery routing). If the
1242%verify% option is set false, the router is skipped when Exim is verifying an
1243address.
1244Setting the %verify% option actually sets two options, %verify_sender% and
1245%verify_recipient%, which independently control the use of the router for
1246sender and recipient verification. You can set these options directly if
1247you want a router to be used for only one type of verification.
1248
1249- If the %address_test% option is set false, the router is skipped when Exim is
1250run with the %-bt% option to test an address routing. This can be helpful when
1251the first router sends all new messages to a scanner of some sort; it makes it
1252possible to use %-bt% to test subsequent delivery routing without having to
1253simulate the effect of the scanner.
1254
1255- Routers can be designated for use only when verifying an address, as
1256opposed to routing it for delivery. The %verify_only% option controls this.
1257
1258- Certain routers can be explicitly skipped when running the routers to check an
1259address given in the SMTP EXPN command (see the %expn% option).
1260
1261- If the %domains% option is set, the domain of the address must be in the set of
1262domains that it defines.
1263
1264- If the %local_parts% option is set, the local part of the address must be in
1265the set of local parts that it defines. If %local_part_prefix% or
1266%local_part_suffix% is in use, the prefix or suffix is removed from the local
1267part before this check. If you want to do precondition tests on local parts
1268that include affixes, you can do so by using a %condition% option (see below)
1269that uses the variables $local_part$, $local_part_prefix$, and
1270$local_part_suffix$ as necessary.
1271
1272- If the %check_local_user% option is set, the local part must be the name of
1273an account on the local host.
1274If this check succeeds, the uid and gid of the local user are placed in
1275$local_user_uid$ and $local_user_gid$; these values can be used in the
1276remaining preconditions.
1277
1278- If the %router_home_directory% option is set, it is expanded at this point,
1279because it overrides the value of $home$. If this expansion were left till
1280later, the value of $home$ as set by %check_local_user% would be used in
1281subsequent tests. Having two different values of $home$ in the same router
1282could lead to confusion.
1283
1284- If the %senders% option is set, the envelope sender address must be in the set
1285of addresses that it defines.
1286
1287- If the %require_files% option is set, the existence or non-existence of
1288specified files is tested.
1289
1290- cindex:[customizing,precondition]
1291If the %condition% option is set, it is evaluated and tested. This option uses
1292an expanded string to allow you to set up your own custom preconditions.
1293Expanded strings are described in chapter <<CHAPexpand>>.
1294
1295
1296Note that %require_files% comes near the end of the list, so you cannot use it
1297to check for the existence of a file in which to lookup up a domain, local
1298part, or sender. However, as these options are all expanded, you can use the
1299%exists% expansion condition to make such tests within each condition. The
1300%require_files% option is intended for checking files that the router may be
1301going to use internally, or which are needed by a specific transport (for
1302example, _.procmailrc_).
1303
1304
1305
1306Delivery in detail
1307~~~~~~~~~~~~~~~~~~
1308cindex:[delivery,in detail]
1309When a message is to be delivered, the sequence of events is as follows:
1310
1311- If a system-wide filter file is specified, the message is passed to it. The
1312filter may add recipients to the message, replace the recipients, discard the
1313message, cause a new message to be generated, or cause the message delivery to
1314fail. The format of the system filter file is the same as for Exim user filter
1315files, described in the separate document entitled
1316'Exim's interfaces to mail filtering'.
1317cindex:[Sieve filter,not available for system filter]
1318(*Note*: Sieve cannot be used for system filter files.)
1319+
1320Some additional features are available in system filters -- see chapter
1321<<CHAPsystemfilter>> for details. Note that a message is passed to the system
1322filter only once per delivery attempt, however many recipients it has. However,
1323if there are several delivery attempts because one or more addresses could not
1324be immediately delivered, the system filter is run each time. The filter
1325condition %first_delivery% can be used to detect the first run of the system
1326filter.
1327
1328- Each recipient address is offered to each configured router in turn, subject
1329to its preconditions, until one is able to handle it. If no router can handle
1330the address, that is, if they all decline, the address is failed. Because
1331routers can be targeted at particular domains, several locally handled domains
1332can be processed entirely independently of each other.
1333
1334- cindex:[routing,loops in]
1335cindex:[loop,while routing]
1336A router that accepts an address may set up a local or a remote transport for
1337it. However, the transport is not run at this time. Instead, the address is
1338placed on a list for the particular transport, to be run later. Alternatively,
1339the router may generate one or more new addresses (typically from alias,
1340forward, or filter files). New addresses are fed back into this process from
1341the top, but in order to avoid loops, a router ignores any address which has an
1342identically-named ancestor that was processed by itself.
1343
1344- When all the routing has been done, addresses that have been successfully
1345handled are passed to their assigned transports. When local transports are
1346doing real local deliveries, they handle only one address at a time, but if a
1347local transport is being used as a pseudo-remote transport (for example, to
1348collect batched SMTP messages for transmission by some other means) multiple
1349addresses can be handled. Remote transports can always handle more than one
1350address at a time, but can be configured not to do so, or to restrict multiple
1351addresses to the same domain.
1352
1353- Each local delivery to a file or a pipe runs in a separate process under a
1354non-privileged uid, and these deliveries are run one at a time. Remote
1355deliveries also run in separate processes, normally under a uid that is private
1356to Exim (``the Exim user''), but in this case, several remote deliveries can be
1357run in parallel. The maximum number of simultaneous remote deliveries for any
1358one message is set by the %remote_max_parallel% option.
1359The order in which deliveries are done is not defined, except that all local
1360deliveries happen before any remote deliveries.
1361
1362- cindex:[queue runner]
1363When it encounters a local delivery during a queue run, Exim checks its retry
1364database to see if there has been a previous temporary delivery failure for the
1365address before running the local transport. If there was a previous failure,
1366Exim does not attempt a new delivery until the retry time for the address is
1367reached. However, this happens only for delivery attempts that are part of a
1368queue run. Local deliveries are always attempted when delivery immediately
1369follows message reception, even if retry times are set for them. This makes for
1370better behaviour if one particular message is causing problems (for example,
1371causing quota overflow, or provoking an error in a filter file).
1372
1373- cindex:[delivery,retry in remote transports]
1374Remote transports do their own retry handling, since an address may be
1375deliverable to one of a number of hosts, each of which may have a different
1376retry time. If there have been previous temporary failures and no host has
1377reached its retry time, no delivery is attempted, whether in a queue run or
1378not. See chapter <<CHAPretry>> for details of retry strategies.
1379
1380- If there were any permanent errors, a bounce message is returned to an
1381appropriate address (the sender in the common case), with details of the error
1382for each failing address. Exim can be configured to send copies of bounce
1383messages to other addresses.
1384
1385- cindex:[delivery,deferral]
1386If one or more addresses suffered a temporary failure, the message is left on
1387the queue, to be tried again later. Delivery of these addresses is said to be
1388'deferred'.
1389
1390- When all the recipient addresses have either been delivered or bounced,
1391handling of the message is complete. The spool files and message log are
1392deleted, though the message log can optionally be preserved if required.
1393
1394
1395
1396
1397Retry mechanism
1398~~~~~~~~~~~~~~~
1399cindex:[delivery,retry mechanism]
1400cindex:[retry,description of mechanism]
1401cindex:[queue runner]
1402Exim's mechanism for retrying messages that fail to get delivered at the first
1403attempt is the queue runner process. You must either run an Exim daemon that
1404uses the %-q% option with a time interval to start queue runners at regular
1405intervals, or use some other means (such as 'cron') to start them. If you do
1406not arrange for queue runners to be run, messages that fail temporarily at the
1407first attempt will remain on your queue for ever. A queue runner process works
1408it way through the queue, one message at a time, trying each delivery that has
1409passed its retry time.
1410You can run several queue runners at once.
1411
1412Exim uses a set of configured rules to determine when next to retry the failing
1413address (see chapter <<CHAPretry>>). These rules also specify when Exim should
1414give up trying to deliver to the address, at which point it generates a bounce
1415message. If no retry rules are set for a particular host, address, and error
1416combination, no retries are attempted, and temporary errors are treated as
1417permanent.
1418
1419
1420
1421Temporary delivery failure
1422~~~~~~~~~~~~~~~~~~~~~~~~~~
1423cindex:[delivery,temporary failure]
1424There are many reasons why a message may not be immediately deliverable to a
1425particular address. Failure to connect to a remote machine (because it, or the
1426connection to it, is down) is one of the most common. Temporary failures may be
1427detected during routing as well as during the transport stage of delivery.
1428Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1429is on a file system where the user is over quota. Exim can be configured to
1430impose its own quotas on local mailboxes; where system quotas are set they will
1431also apply.
1432
1433If a host is unreachable for a period of time, a number of messages may be
1434waiting for it by the time it recovers, and sending them in a single SMTP
1435connection is clearly beneficial. Whenever a delivery to a remote host is
1436deferred,
1437
1438cindex:[hints database]
1439Exim makes a note in its hints database, and whenever a successful
1440SMTP delivery has happened, it looks to see if any other messages are waiting
1441for the same host. If any are found, they are sent over the same SMTP
1442connection, subject to a configuration limit as to the maximum number in any
1443one connection.
1444
1445
1446
1447
1448Permanent delivery failure
1449~~~~~~~~~~~~~~~~~~~~~~~~~~
1450cindex:[delivery,permanent failure]
1451cindex:[bounce message,when generated]
1452When a message cannot be delivered to some or all of its intended recipients, a
1453bounce message is generated. Temporary delivery failures turn into permanent
1454errors when their timeout expires. All the addresses that fail in a given
1455delivery attempt are listed in a single message. If the original message has
1456many recipients, it is possible for some addresses to fail in one delivery
1457attempt and others to fail subsequently, giving rise to more than one bounce
1458message. The wording of bounce messages can be customized by the administrator.
1459See chapter <<CHAPemsgcust>> for details.
1460
1461cindex:['X-Failed-Recipients:' header line]
1462Bounce messages contain an 'X-Failed-Recipients:' header line that lists the
1463failed addresses, for the benefit of programs that try to analyse such messages
1464automatically.
1465
1466cindex:[bounce message,recipient of]
1467A bounce message is normally sent to the sender of the original message, as
1468obtained from the message's envelope. For incoming SMTP messages, this is the
1469address given in the MAIL command. However, when an address is
1470expanded via a forward or alias file, an alternative address can be specified
1471for delivery failures of the generated addresses. For a mailing list expansion
1472(see section <<SECTmailinglists>>) it is common to direct bounce messages to the
1473manager of the list.
1474
1475
1476
1477
1478Failures to deliver bounce messages
1479~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1480cindex:[bounce message,failure to deliver]
1481If a bounce message (either locally generated or received from a remote host)
1482itself suffers a permanent delivery failure, the message is left on the queue,
1483but it is frozen, awaiting the attention of an administrator. There are options
1484which can be used to make Exim discard such failed messages, or to keep them
1485for only a short time (see %timeout_frozen_after% and
1486%ignore_bounce_errors_after%).
1487
1488
1489
1490
1491
1492////////////////////////////////////////////////////////////////////////////
1493////////////////////////////////////////////////////////////////////////////
1494
1495Building and installing Exim
1496----------------------------
1497
1498cindex:[building Exim]
1499
1500Unpacking
1501~~~~~~~~~
1502Exim is distributed as a gzipped or bzipped tar file which, when upacked,
1503creates a directory with the name of the current release (for example,
1504_exim-{version}_) into which the following files are placed:
1505
1506[frame="none"]
1507`--------------------`--------------------------------------------------------
1508_ACKNOWLEDGMENTS_ contains some acknowledgments
1509_CHANGES_ contains a reference to where changes are documented
1510_LICENCE_ the GNU General Public Licence
1511_Makefile_ top-level make file
1512_NOTICE_ conditions for the use of Exim
1513_README_ list of files, directories and simple build instructions
1514------------------------------------------------------------------------------
1515
1516Other files whose names begin with _README_ may also be present. The
1517following subdirectories are created:
1518
1519[frame="none"]
1520`--------------------`------------------------------------------------
1521_Local_ an empty directory for local configuration files
1522_OS_ OS-specific files
1523_doc_ documentation files
1524_exim_monitor_ source files for the Exim monitor
1525_scripts_ scripts used in the build process
1526_src_ remaining source files
1527_util_ independent utilities
1528----------------------------------------------------------------------
1529
1530The main utility programs are contained in the _src_ directory, and are built
1531with the Exim binary. The _util_ directory contains a few optional scripts
1532that may be useful to some sites.
1533
1534
1535Multiple machine architectures and operating systems
1536~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1537cindex:[building Exim,multiple OS/architectures]
1538The building process for Exim is arranged to make it easy to build binaries for
1539a number of different architectures and operating systems from the same set of
1540source files. Compilation does not take place in the _src_ directory. Instead,
1541a 'build directory' is created for each architecture and operating system.
1542
1543cindex:[symbolic link,to build directory]
1544Symbolic links to the sources are installed in this directory, which is where
1545the actual building takes place.
1546
1547In most cases, Exim can discover the machine architecture and operating system
1548for itself, but the defaults can be overridden if necessary.
1549
1550
1551[[SECTdb]]
1552DBM libraries
1553~~~~~~~~~~~~~
1554cindex:[DBM libraries, discussion of]
1555cindex:[hints database,DBM files used for]
1556Even if you do not use any DBM files in your configuration, Exim still needs a
1557DBM library in order to operate, because it uses indexed files for its hints
1558databases. Unfortunately, there are a number of DBM libraries in existence, and
1559different operating systems often have different ones installed.
1560
1561cindex:[Solaris,DBM library for]
1562cindex:[IRIX, DBM library for]
1563cindex:[BSD, DBM library for]
1564cindex:[Linux, DBM library for]
1565If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1566Linux distribution, the DBM configuration should happen automatically, and you
1567may be able to ignore this section. Otherwise, you may have to learn more than
1568you would like about DBM libraries from what follows.
1569
1570cindex:['ndbm' DBM library]
1571Licensed versions of Unix normally contain a library of DBM functions operating
1572via the 'ndbm' interface, and this is what Exim expects by default. Free
1573versions of Unix seem to vary in what they contain as standard. In particular,
1574some early versions of Linux have no default DBM library, and different
1575distributors have chosen to bundle different libraries with their packaged
1576versions. However, the more recent releases seem to have standardised on the
1577Berkeley DB library.
1578
1579Different DBM libraries have different conventions for naming the files they
1580use. When a program opens a file called _dbmfile_, there are four
1581possibilities:
1582
1583. A traditional 'ndbm' implementation, such as that supplied as part of
1584Solaris, operates on two files called _dbmfile.dir_ and _dbmfile.pag_.
1585
1586. cindex:['gdbm' DBM library]
1587The GNU library, 'gdbm', operates on a single file. If used via its 'ndbm'
1588compatibility interface it makes two different hard links to it with names
1589_dbmfile.dir_ and _dbmfile.pag_, but if used via its native interface, the
1590file name is used unmodified.
1591
1592. cindex:[Berkeley DB library]
1593The Berkeley DB package, if called via its 'ndbm' compatibility interface,
1594operates on a single file called _dbmfile.db_, but otherwise looks to the
1595programmer exactly the same as the traditional 'ndbm' implementation.
1596
1597. If the Berkeley package is used in its native mode, it operates on a single
1598file called _dbmfile_; the programmer's interface is somewhat different to
1599the traditional 'ndbm' interface.
1600
1601. To complicate things further, there are several very different versions of the
1602Berkeley DB package. Version 1.85 was stable for a very long time, releases
16032.'x' and 3.'x' were current for a while, but the latest versions are now
1604numbered 4.'x'. Maintenance of some of the earlier releases has ceased. All
1605versions of Berkeley DB can be obtained from
1606+
1607&&&
1608*http://www.sleepycat.com/[]*
1609&&&
1610
1611. cindex:['tdb' DBM library]
1612Yet another DBM library, called 'tdb', has become available from
1613+
1614&&&
1615*http://download.sourceforge.net/tdb[]*
1616&&&
1617+
1618It has its own interface, and also operates on a single file.
1619
1620cindex:[USE_DB]
1621cindex:[DBM libraries, configuration for building]
1622Exim and its utilities can be compiled to use any of these interfaces. In order
1623to use any version of the Berkeley DB package in native mode, you must set
1624USE_DB in an appropriate configuration file (typically
1625_Local/Makefile_). For example:
1626
1627 USE_DB=yes
1628
1629Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1630error is diagnosed if you set more than one of these.
1631
1632At the lowest level, the build-time configuration sets none of these options,
1633thereby assuming an interface of type (1). However, some operating system
1634configuration files (for example, those for the BSD operating systems and
1635Linux) assume type (4) by setting USE_DB as their default, and the
1636configuration files for Cygwin set USE_GDBM. Anything you set in
1637_Local/Makefile_, however, overrides these system defaults.
1638
1639As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1640necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1641in one of these lines:
1642
1643 DBMLIB = -ldb
1644 DBMLIB = -ltdb
1645
1646Settings like that will work if the DBM library is installed in the standard
1647place. Sometimes it is not, and the library's header file may also not be in
1648the default path. You may need to set INCLUDE to specify where the header
1649file is, and to specify the path to the library more fully in DBMLIB, as in
1650this example:
1651
1652 INCLUDE=-I/usr/local/include/db-4.1
1653 DBMLIB=/usr/local/lib/db-4.1/libdb.a
1654
1655
1656There is further detailed discussion about the various DBM libraries in the
1657file _doc/dbm.discuss.txt_ in the Exim distribution.
1658
1659
1660
1661Pre-building configuration
1662~~~~~~~~~~~~~~~~~~~~~~~~~~
1663cindex:[building Exim,pre-building configuration]
1664cindex:[configuration for building Exim]
1665cindex:[_Local/Makefile_]
1666cindex:[_src/EDITME_]
1667Before building Exim, a local configuration file that specifies options
1668independent of any operating system has to be created with the name
1669_Local/Makefile_. A template for this file is supplied as the file
1670_src/EDITME_, and it contains full descriptions of all the option settings
1671therein. These descriptions are therefore not repeated here. If you are
1672building Exim for the first time, the simplest thing to do is to copy
1673_src/EDITME_ to _Local/Makefile_, then read it and edit it appropriately.
1674
1675There are three settings that you must supply, because Exim will not build
1676without them. They are the location of the run time configuration file
1677(CONFIGURE_FILE), the directory in which Exim binaries will be installed
1678(BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1679maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1680a colon-separated list of file names; Exim uses the first of them that exists.
1681
1682There are a few other parameters that can be specified either at build time or
1683at run time, to enable the same binary to be used on a number of different
1684machines. However, if the locations of Exim's spool directory and log file
1685directory (if not within the spool directory) are fixed, it is recommended that
1686you specify them in _Local/Makefile_ instead of at run time, so that errors
1687detected early in Exim's execution (such as a malformed configuration file) can
1688be logged.
1689
1690cindex:[content scanning,specifying at build time]
1691Exim's interfaces for calling virus and spam scanning sofware directly from
1692access control lists are not compiled by default. If you want to include these
1693facilities, you need to set
1694
1695 WITH_CONTENT_SCAN=yes
1696
1697in your _Local/Makefile_. For details of the facilities themselves, see
1698chapter <<CHAPexiscan>>.
1699
1700
1701cindex:[_Local/eximon.conf_]
1702cindex:[_exim_monitor/EDITME_]
1703If you are going to build the Exim monitor, a similar configuration process is
1704required. The file _exim_monitor/EDITME_ must be edited appropriately for
1705your installation and saved under the name _Local/eximon.conf_. If you are
1706happy with the default settings described in _exim_monitor/EDITME_,
1707_Local/eximon.conf_ can be empty, but it must exist.
1708
1709This is all the configuration that is needed in straightforward cases for known
1710operating systems. However, the building process is set up so that it is easy
1711to override options that are set by default or by operating-system-specific
1712configuration files, for example to change the name of the C compiler, which
1713defaults to %gcc%. See section <<SECToverride>> below for details of how to do
1714this.
1715
1716
1717
1718Support for iconv()
1719~~~~~~~~~~~~~~~~~~~
1720cindex:['iconv()' support]
1721The contents of header lines in messages may be encoded according to the rules
1722described RFC 2047. This makes it possible to transmit characters that are not
1723in the ASCII character set, and to label them as being in a particular
1724character set. When Exim is inspecting header lines by means of the %\$h_%
1725mechanism, it decodes them, and translates them into a specified character set
1726(default ISO-8859-1). The translation is possible only if the operating system
1727supports the 'iconv()' function.
1728
1729However, some of the operating systems that supply 'iconv()' do not support
1730very many conversions. The GNU %libiconv% library (available from
1731*http://www.gnu.org/software/libiconv/[]*) can be installed on such systems to
1732remedy this deficiency, as well as on systems that do not supply 'iconv()' at
1733all. After installing %libiconv%, you should add
1734
1735 HAVE_ICONV=yes
1736
1737to your _Local/Makefile_ and rebuild Exim.
1738
1739
1740
1741[[SECTinctlsssl]]
1742Including TLS/SSL encryption support
1743~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1744cindex:[TLS,including support for TLS]
1745cindex:[encryption,including support for]
1746cindex:[SUPPORT_TLS]
1747cindex:[OpenSSL,building Exim with]
1748cindex:[GnuTLS,building Exim with]
1749Exim can be built to support encrypted SMTP connections, using the STARTTLS
1750command as per RFC 2487. It can also support legacy clients that expect to
1751start a TLS session immediately on connection to a non-standard port (see the
1752%tls_on_connect_ports% runtime option and the %-tls-on-connect% command
1753line option).
1754
1755If you want to build Exim with TLS support, you must first install either the
1756OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1757implementing SSL.
1758
1759If OpenSSL is installed, you should set
1760
1761 SUPPORT_TLS=yes
1762 TLS_LIBS=-lssl -lcrypto
1763
1764in _Local/Makefile_. You may also need to specify the locations of the
1765OpenSSL library and include files. For example:
1766
1767 SUPPORT_TLS=yes
1768 TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1769 TLS_INCLUDE=-I/usr/local/openssl/include/
1770
1771cindex:[USE_GNUTLS]
1772If GnuTLS is installed, you should set
1773
1774 SUPPORT_TLS=yes
1775 USE_GNUTLS=yes
1776 TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1777
1778in _Local/Makefile_, and again you may need to specify the locations of the
1779library and include files. For example:
1780
1781 SUPPORT_TLS=yes
1782 USE_GNUTLS=yes
1783 TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1784 TLS_INCLUDE=-I/usr/gnu/include
1785
1786You do not need to set TLS_INCLUDE if the relevant directory is already
1787specified in INCLUDE. Details of how to configure Exim to make use of TLS
1788are given in chapter <<CHAPTLS>>.
1789
1790
1791
1792
1793Use of tcpwrappers
1794~~~~~~~~~~~~~~~~~~
1795cindex:[tcpwrappers, building Exim to support]
1796cindex:[USE_TCP_WRAPPERS]
1797Exim can be linked with the 'tcpwrappers' library in order to check incoming
1798SMTP calls using the 'tcpwrappers' control files. This may be a convenient
1799alternative to Exim's own checking facilities for installations that are
1800already making use of 'tcpwrappers' for other purposes. To do this, you should
1801set USE_TCP_WRAPPERS in _Local/Makefile_, arrange for the file
1802_tcpd.h_ to be available at compile time, and also ensure that the library
1803_libwrap.a_ is available at link time, typically by including %-lwrap% in
1804EXTRALIBS_EXIM. For example, if 'tcpwrappers' is installed in
1805_/usr/local_, you might have
1806
1807 USE_TCP_WRAPPERS=yes
1808 CFLAGS=-O -I/usr/local/include
1809 EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1810
1811in _Local/Makefile_. The name to use in the 'tcpwrappers' control files is
1812``exim''. For example, the line
1813
1814 exim : LOCAL 192.168.1. .friendly.domain.example
1815
1816in your _/etc/hosts.allow_ file allows connections from the local host, from
1817the subnet 192.168.1.0/24, and from all hosts in 'friendly.domain.example'.
1818All other connections are denied. Consult the 'tcpwrappers' documentation for
1819further details.
1820
1821
1822
1823Including support for IPv6
1824~~~~~~~~~~~~~~~~~~~~~~~~~~
1825cindex:[IPv6,including support for]
1826Exim contains code for use on systems that have IPv6 support. Setting
1827`HAVE_IPV6=YES` in _Local/Makefile_ causes the IPv6 code to be included;
1828it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1829where the IPv6 support is not fully integrated into the normal include and
1830library files.
1831
1832Two different types of DNS record for handling IPv6 addresses have been
1833defined. AAAA records (analagous to A records for IPv4) are in use, and are
1834currently seen as the mainstream. Another record type called A6 was proposed
1835as better than AAAA because it had more flexibility. However, it was felt to be
1836over-complex, and its status was reduced to ``experimental''. It is not known
1837if anyone is actually using A6 records. Exim has support for A6 records, but
1838this is included only if you set `SUPPORT_A6=YES` in _Local/Makefile_. The
1839support has not been tested for some time.
1840
1841
1842
1843The building process
1844~~~~~~~~~~~~~~~~~~~~
1845cindex:[build directory]
1846Once _Local/Makefile_ (and _Local/eximon.conf_, if required) have been
1847created, run 'make' at the top level. It determines the architecture and
1848operating system types, and creates a build directory if one does not exist.
1849For example, on a Sun system running Solaris 8, the directory
1850_build-SunOS5-5.8-sparc_ is created.
1851cindex:[symbolic link,to source files]
1852Symbolic links to relevant source files are installed in the build directory.
1853
1854*Warning*: The %-j% (parallel) flag must not be used with 'make'; the
1855building process fails if it is set.
1856
1857If this is the first time 'make' has been run, it calls a script that builds
1858a make file inside the build directory, using the configuration files from the
1859_Local_ directory. The new make file is then passed to another instance of
1860'make'. This does the real work, building a number of utility scripts, and
1861then compiling and linking the binaries for the Exim monitor (if configured), a
1862number of utility programs, and finally Exim itself. The command 'make
1863makefile' can be used to force a rebuild of the make file in the build
1864directory, should this ever be necessary.
1865
1866If you have problems building Exim, check for any comments there may be in the
1867_README_ file concerning your operating system, and also take a look at the
1868FAQ, where some common problems are covered.
1869
1870
1871
1872
1873[[SECToverride]]
1874Overriding build-time options for Exim
1875~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1876cindex:[build-time options, overriding]
1877The main make file that is created at the beginning of the building process
1878consists of the concatenation of a number of files which set configuration
1879values, followed by a fixed set of 'make' instructions. If a value is set
1880more than once, the last setting overrides any previous ones. This provides a
1881convenient way of overriding defaults. The files that are concatenated are, in
1882order:
1883
1884&&&
1885_OS/Makefile-Default_
1886_OS/Makefile-_<'ostype'>
1887_Local/Makefile_
1888_Local/Makefile-_<'ostype'>
1889_Local/Makefile-_<'archtype'>
1890_Local/Makefile-_<'ostype'>-<'archtype'>
1891_OS/Makefile-Base_
1892&&&
1893
1894cindex:[_Local/Makefile_]
1895cindex:[building Exim,operating system type]
1896cindex:[building Exim,architecture type]
1897where <'ostype'> is the operating system type and <'archtype'> is the
1898architecture type. _Local/Makefile_ is required to exist, and the building
1899process fails if it is absent. The other three _Local_ files are optional,
1900and are often not needed.
1901
1902The values used for <'ostype'> and <'archtype'> are obtained from scripts
1903called _scripts/os-type_ and _scripts/arch-type_ respectively. If either of
1904the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
1905values are used, thereby providing a means of forcing particular settings.
1906Otherwise, the scripts try to get values from the %uname% command. If this
1907fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
1908of 'ad hoc' transformations are then applied, to produce the standard names
1909that Exim expects. You can run these scripts directly from the shell in order
1910to find out what values are being used on your system.
1911
1912
1913_OS/Makefile-Default_ contains comments about the variables that are set
1914therein. Some (but not all) are mentioned below. If there is something that
1915needs changing, review the contents of this file and the contents of the make
1916file for your operating system (_OS/Makefile-<ostype>_) to see what the
1917default values are.
1918
1919
1920cindex:[building Exim,overriding default settings]
1921If you need to change any of the values that are set in _OS/Makefile-Default_
1922or in _OS/Makefile-<ostype>_, or to add any new definitions, you do not
1923need to change the original files. Instead, you should make the changes by
1924putting the new values in an appropriate _Local_ file. For example,
1925cindex:[Tru64-Unix build-time settings]
1926when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
1927formerly DEC-OSF1) operating system, it is necessary to specify that the C
1928compiler is called 'cc' rather than 'gcc'. Also, the compiler must be
1929called with the option %-std1%, to make it recognize some of the features of
1930Standard C that Exim uses. (Most other compilers recognize Standard C by
1931default.) To do this, you should create a file called _Local/Makefile-OSF1_
1932containing the lines
1933
1934 CC=cc
1935 CFLAGS=-std1
1936
1937If you are compiling for just one operating system, it may be easier to put
1938these lines directly into _Local/Makefile_.
1939
1940Keeping all your local configuration settings separate from the distributed
1941files makes it easy to transfer them to new versions of Exim simply by copying
1942the contents of the _Local_ directory.
1943
1944
1945cindex:[NIS lookup type,including support for]
1946cindex:[NIS+ lookup type,including support for]
1947cindex:[LDAP,including support for]
1948cindex:[lookup,inclusion in binary]
1949Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
1950lookup, but not all systems have these components installed, so the default is
1951not to include the relevant code in the binary. All the different kinds of file
1952and database lookup that Exim supports are implemented as separate code modules
1953which are included only if the relevant compile-time options are set. In the
1954case of LDAP, NIS, and NIS+, the settings for _Local/Makefile_ are:
1955
1956 LOOKUP_LDAP=yes
1957 LOOKUP_NIS=yes
1958 LOOKUP_NISPLUS=yes
1959
1960and similar settings apply to the other lookup types. They are all listed in
1961_src/EDITME_. In most cases the relevant include files and interface
1962libraries need to be installed before compiling Exim.
1963cindex:[cdb,including support for]
1964However, in the case of cdb, which is included in the binary only if
1965
1966 LOOKUP_CDB=yes
1967
1968is set, the code is entirely contained within Exim, and no external include
1969files or libraries are required. When a lookup type is not included in the
1970binary, attempts to configure Exim to use it cause run time configuration
1971errors.
1972
1973cindex:[Perl,including support for]
1974Exim can be linked with an embedded Perl interpreter, allowing Perl
1975subroutines to be called during string expansion. To enable this facility,
1976
1977 EXIM_PERL=perl.o
1978
1979must be defined in _Local/Makefile_. Details of this facility are given in
1980chapter <<CHAPperl>>.
1981
1982cindex:[X11 libraries, location of]
1983The location of the X11 libraries is something that varies a lot between
1984operating systems, and of course there are different versions of X11 to cope
1985with. Exim itself makes no use of X11, but if you are compiling the Exim
1986monitor, the X11 libraries must be available.
1987The following three variables are set in _OS/Makefile-Default_:
1988
1989 X11=/usr/X11R6
1990 XINCLUDE=-I$(X11)/include
1991 XLFLAGS=-L$(X11)/lib
1992
1993These are overridden in some of the operating-system configuration files. For
1994example, in _OS/Makefile-SunOS5_ there is
1995
1996 X11=/usr/openwin
1997 XINCLUDE=-I$(X11)/include
1998 XLFLAGS=-L$(X11)/lib -R$(X11)/lib
1999
2000If you need to override the default setting for your operating system, place a
2001definition of all three of these variables into your
2002_Local/Makefile-<ostype>_ file.
2003
2004cindex:[EXTRALIBS]
2005If you need to add any extra libraries to the link steps, these can be put in a
2006variable called EXTRALIBS, which appears in all the link commands, but by
2007default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2008command for linking the main Exim binary, and not for any associated utilities.
2009
2010cindex:[DBM libraries, configuration for building]
2011There is also DBMLIB, which appears in the link commands for binaries that
2012use DBM functions (see also section <<SECTdb>>). Finally, there is
2013EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2014binary, and which can be used, for example, to include additional X11
2015libraries.
2016
2017cindex:[configuration file,editing]
2018The make file copes with rebuilding Exim correctly if any of the configuration
2019files are edited. However, if an optional configuration file is deleted, it is
2020necessary to touch the associated non-optional file (that is, _Local/Makefile_
2021or _Local/eximon.conf_) before rebuilding.
2022
2023
2024OS-specific header files
2025~~~~~~~~~~~~~~~~~~~~~~~~
2026cindex:[_os.h_]
2027cindex:[building Exim,OS-specific C header files]
2028The _OS_ directory contains a number of files with names of the form
2029_os.h-<ostype>_. These are system-specific C header files that should not
2030normally need to be changed. There is a list of macro settings that are
2031recognized in the file _OS/os.configuring_, which should be consulted if you
2032are porting Exim to a new operating system.
2033
2034
2035
2036Overriding build-time options for the monitor
2037~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2038cindex:[building Eximon,overriding default options]
2039A similar process is used for overriding things when building the Exim monitor,
2040where the files that are involved are
2041
2042&&&
2043_OS/eximon.conf-Default_
2044_OS/eximon.conf-_<'ostype'>
2045_Local/eximon.conf_
2046_Local/eximon.conf-_<'ostype'>
2047_Local/eximon.conf-_<'archtype'>
2048_Local/eximon.conf-_<'ostype'>-<'archtype'>
2049&&&
2050
2051cindex:[_Local/eximon.conf_]
2052As with Exim itself, the final three files need not exist, and in this case the
2053_OS/eximon.conf-<ostype>_ file is also optional. The default values in
2054_OS/eximon.conf-Default_ can be overridden dynamically by setting environment
2055variables of the same name, preceded by EXIMON_. For example, setting
2056EXIMON_LOG_DEPTH in the environment overrides the value of
2057LOG_DEPTH at run time.
2058
2059
2060
2061
2062Installing Exim binaries and scripts
2063~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2064cindex:[installing Exim]
2065cindex:[BIN_DIRECTORY]
2066The command 'make install' runs the 'exim_install' script with no
2067arguments. The script copies binaries and utility scripts into the directory
2068whose name is specified by the BIN_DIRECTORY setting in
2069_Local/Makefile_.
2070
2071cindex:[CONFIGURE_FILE]
2072Exim's run time configuration file is named by the CONFIGURE_FILE setting
2073in _Local/Makefile_. If this names a single file, and the file does not
2074exist, the default configuration file _src/configure.default_ is copied there
2075by the installation script. If a run time configuration file already exists, it
2076is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2077alternative files, no default is installed.
2078
2079cindex:[system aliases file]
2080cindex:[_/etc/aliases_]
2081One change is made to the default configuration file when it is installed: the
2082default configuration contains a router that references a system aliases file.
2083The path to this file is set to the value specified by
2084SYSTEM_ALIASES_FILE in _Local/Makefile_ (_/etc/aliases_ by default).
2085If the system aliases file does not exist, the installation script creates it,
2086and outputs a comment to the user.
2087
2088The created file contains no aliases, but it does contain comments about the
2089aliases a site should normally have. Mail aliases have traditionally been
2090kept in _/etc/aliases_. However, some operating systems are now using
2091_/etc/mail/aliases_. You should check if yours is one of these, and change
2092Exim's configuration if necessary.
2093
2094The default configuration uses the local host's name as the only local domain,
2095and is set up to do local deliveries into the shared directory _/var/mail_,
2096running as the local user. System aliases and _.forward_ files in users' home
2097directories are supported, but no NIS or NIS+ support is configured. Domains
2098other than the name of the local host are routed using the DNS, with delivery
2099over SMTP.
2100
2101cindex:[setuid,installing Exim with]
2102The install script copies files only if they are newer than the files they are
2103going to replace. The Exim binary is required to be owned by root and have the
2104'setuid' bit set, for normal configurations. Therefore, you must run 'make
2105install' as root so that it can set up the Exim binary in this way. However, in
2106some special situations (for example, if a host is doing no local deliveries)
2107it may be possible to run Exim without making the binary setuid root (see
2108chapter <<CHAPsecurity>> for details).
2109
2110It is possible to install Exim for special purposes (such as building a binary
2111distribution) in a private part of the file system. You can do this by a
2112command such as
2113
2114 make DESTDIR=/some/directory/ install
2115
2116This has the effect of pre-pending the specified directory to all the file
2117paths, except the name of the system aliases file that appears in the default
2118configuration. (If a default alias file is created, its name 'is' modified.)
2119For backwards compatibility, ROOT is used if DESTDIR is not set,
2120but this usage is deprecated.
2121
2122cindex:[installing Exim,what is not installed]
2123Running 'make install' does not copy the Exim 4 conversion script
2124'convert4r4', or the 'pcretest' test program. You will probably run the
2125first of these only once (if you are upgrading from Exim 3), and the second
2126isn't really part of Exim. None of the documentation files in the _doc_
2127directory are copied, except for the info files when you have set
2128INFO_DIRECTORY, as described in section <<SECTinsinfdoc>> below.
2129
2130For the utility programs, old versions are renamed by adding the suffix _.O_
2131to their names. The Exim binary itself, however, is handled differently. It is
2132installed under a name that includes the version number and the compile number,
2133for example _exim-{version}-1_. The script then arranges for a symbolic link
2134called _exim_ to point to the binary. If you are updating a previous version
2135of Exim, the script takes care to ensure that the name _exim_ is never absent
2136from the directory (as seen by other processes).
2137
2138cindex:[installing Exim,testing the script]
2139If you want to see what the 'make install' will do before running it for
2140real, you can pass the %-n% option to the installation script by this command:
2141
2142 make INSTALL_ARG=-n install
2143
2144The contents of the variable INSTALL_ARG are passed to the installation
2145script. You do not need to be root to run this test. Alternatively, you can run
2146the installation script directly, but this must be from within the build
2147directory. For example, from the top-level Exim directory you could use this
2148command:
2149
2150 (cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2151
2152cindex:[installing Exim,install script options]
2153There are two other options that can be supplied to the installation script.
2154
2155- %-no_chown% bypasses the call to change the owner of the installed binary
2156to root, and the call to make it a setuid binary.
2157
2158- %-no_symlink% bypasses the setting up of the symbolic link _exim_ to the
2159installed binary.
2160
2161INSTALL_ARG can be used to pass these options to the script. For example:
2162
2163 make INSTALL_ARG=-no_symlink install
2164
2165
2166The installation script can also be given arguments specifying which files are
2167to be copied. For example, to install just the Exim binary, and nothing else,
2168without creating the symbolic link, you could use:
2169
2170 make INSTALL_ARG='-no_symlink exim' install
2171
2172
2173
2174
2175[[SECTinsinfdoc]]
2176Installing info documentation
2177~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2178cindex:[installing Exim,'info' documentation]
2179Not all systems use the GNU 'info' system for documentation, and for this
2180reason, the Texinfo source of Exim's documentation is not included in the main
2181distribution. Instead it is available separately from the ftp site (see section
2182<<SECTavail>>).
2183
2184If you have defined INFO_DIRECTORY in _Local/Makefile_ and the Texinfo
2185source of the documentation is found in the source tree, running 'make
2186install' automatically builds the info files and installs them.
2187
2188
2189
2190Setting up the spool directory
2191~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2192cindex:[spool directory,creating]
2193When it starts up, Exim tries to create its spool directory if it does not
2194exist. The Exim uid and gid are used for the owner and group of the spool
2195directory. Sub-directories are automatically created in the spool directory as
2196necessary.
2197
2198
2199
2200
2201Testing
2202~~~~~~~
2203cindex:[testing,installation]
2204Having installed Exim, you can check that the run time configuration file is
2205syntactically valid by running the following command, which assumes that the
2206Exim binary directory is within your PATH environment variable:
2207
2208 exim -bV
2209
2210If there are any errors in the configuration file, Exim outputs error messages.
2211Otherwise it outputs the version number and build date,
2212the DBM library that is being used, and information about which drivers and
2213other optional code modules are included in the binary.
2214Some simple routing tests can be done by using the address testing option. For
2215example,
2216
2217 exim -bt <local username>
2218
2219should verify that it recognizes a local mailbox, and
2220
2221 exim -bt <remote address>
2222
2223a remote one. Then try getting it to deliver mail, both locally and remotely.
2224This can be done by passing messages directly to Exim, without going through a
2225user agent. For example:
2226
2227 exim -v postmaster@your.domain.example
2228 From: user@your.domain.example
2229 To: postmaster@your.domain.example
2230 Subject: Testing Exim
2231
2232 This is a test message.
2233 ^D
2234
2235The %-v% option causes Exim to output some verification of what it is doing.
2236In this case you should see copies of three log lines, one for the message's
2237arrival, one for its delivery, and one containing ``Completed''.
2238
2239cindex:[delivery,problems with]
2240If you encounter problems, look at Exim's log files ('mainlog' and
2241'paniclog') to see if there is any relevant information there. Another source
2242of information is running Exim with debugging turned on, by specifying the
2243%-d% option. If a message is stuck on Exim's spool, you can force a delivery
2244with debugging turned on by a command of the form
2245
2246 exim -d -M <message-id>
2247
2248You must be root or an ``admin user'' in order to do this. The %-d% option
2249produces rather a lot of output, but you can cut this down to specific areas.
2250For example, if you use %-d-all+route% only the debugging information relevant
2251to routing is included. (See the %-d% option in chapter <<CHAPcommandline>> for
2252more details.)
2253
2254cindex:[``sticky'' bit]
2255cindex:[lock files]
2256One specific problem that has shown up on some sites is the inability to do
2257local deliveries into a shared mailbox directory, because it does not have the
2258``sticky bit'' set on it. By default, Exim tries to create a lock file before
2259writing to a mailbox file, and if it cannot create the lock file, the delivery
2260is deferred. You can get round this either by setting the ``sticky bit'' on the
2261directory, or by setting a specific group for local deliveries and allowing
2262that group to create files in the directory (see the comments above the
2263^local_delivery^ transport in the default configuration file). Another
2264approach is to configure Exim not to use lock files, but just to rely on
2265'fcntl()' locking instead. However, you should do this only if all user
2266agents also use 'fcntl()' locking. For further discussion of locking issues,
2267see chapter <<CHAPappendfile>>.
2268
2269One thing that cannot be tested on a system that is already running an MTA is
2270the receipt of incoming SMTP mail on the standard SMTP port. However, the
2271%-oX% option can be used to run an Exim daemon that listens on some other
2272port, or 'inetd' can be used to do this. The %-bh% option and the
2273'exim_checkaccess' utility can be used to check out policy controls on
2274incoming SMTP mail.
2275
2276Testing a new version on a system that is already running Exim can most easily
2277be done by building a binary with a different CONFIGURE_FILE setting. From
2278within the run time configuration, all other file and directory names
2279that Exim uses can be altered, in order to keep it entirely clear of the
2280production version.
2281
2282
2283Replacing another MTA with Exim
2284~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2285cindex:[replacing another MTA]
2286Building and installing Exim for the first time does not of itself put it in
2287general use. The name by which the system's MTA is called by mail user agents
2288is either _/usr/sbin/sendmail_, or _/usr/lib/sendmail_ (depending on the
2289operating system), and it is necessary to make this name point to the 'exim'
2290binary in order to get the user agents to pass messages to Exim. This is
2291normally done by renaming any existing file and making _/usr/sbin/sendmail_
2292or _/usr/lib/sendmail_
2293
2294cindex:[symbolic link,to 'exim' binary]
2295a symbolic link to the 'exim' binary. It is a good idea to remove any setuid
2296privilege and executable status from the old MTA. It is then necessary to stop
2297and restart the mailer daemon, if one is running.
2298
2299cindex:[FreeBSD, MTA indirection]
2300cindex:[_/etc/mail/mailer.conf_]
2301Some operating systems have introduced alternative ways of switching MTAs. For
2302example, if you are running FreeBSD, you need to edit the file
2303_/etc/mail/mailer.conf_ instead of setting up a symbolic link as just
2304described. A typical example of the contents of this file for running Exim is
2305as follows:
2306
2307 sendmail /usr/exim/bin/exim
2308 send-mail /usr/exim/bin/exim
2309 mailq /usr/exim/bin/exim -bp
2310 newaliases /usr/bin/true
2311
2312
2313Once you have set up the symbolic link, or edited _/etc/mail/mailer.conf_,
2314your Exim installation is ``live''. Check it by sending a message from your
2315favourite user agent.
2316
2317You should consider what to tell your users about the change of MTA. Exim may
2318have different capabilities to what was previously running, and there are
2319various operational differences such as the text of messages produced by
2320command line options and in bounce messages. If you allow your users to make
2321use of Exim's filtering capabilities, you should make the document entitled
2322'Exim's interface to mail filtering'
2323available to them.
2324
2325
2326
2327Upgrading Exim
2328~~~~~~~~~~~~~~
2329cindex:[upgrading Exim]
2330If you are already running Exim on your host, building and installing a new
2331version automatically makes it available to MUAs, or any other programs that
2332call the MTA directly. However, if you are running an Exim daemon, you do need
2333to send it a HUP signal, to make it re-exec itself, and thereby pick up the new
2334binary. You do not need to stop processing mail in order to install a new
2335version of Exim.
2336
2337
2338
2339Stopping the Exim daemon on Solaris
2340~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2341cindex:[Solaris,stopping Exim on]
2342The standard command for stopping the mailer daemon on Solaris is
2343
2344 /etc/init.d/sendmail stop
2345
2346If _/usr/lib/sendmail_ has been turned into a symbolic link, this script
2347fails to stop Exim because it uses the command 'ps -e' and greps the output
2348for the text ``sendmail''; this is not present because the actual program name
2349(that is, ``exim'') is given by the 'ps' command with these options. A solution
2350is to replace the line that finds the process id with something like
2351
2352 pid=`cat /var/spool/exim/exim-daemon.pid`
2353
2354to obtain the daemon's pid directly from the file that Exim saves it in.
2355
2356Note, however, that stopping the daemon does not ``stop Exim''. Messages can
2357still be received from local processes, and if automatic delivery is configured
2358(the normal case), deliveries will still occur.
2359
2360
2361
2362
2363////////////////////////////////////////////////////////////////////////////
2364////////////////////////////////////////////////////////////////////////////
2365
2366[[CHAPcommandline]]
2367The Exim command line
2368---------------------
2369cindex:[command line,options]
2370cindex:[options,command line]
2371Exim's command line takes the standard Unix form of a sequence of options,
2372each starting with a hyphen character, followed by a number of arguments. The
2373options are compatible with the main options of Sendmail, and there are also
2374some additional options, some of which are compatible with Smail 3. Certain
2375combinations of options do not make sense, and provoke an error if used.
2376The form of the arguments depends on which options are set.
2377
2378
2379Setting options by program name
2380~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2381cindex:['mailq']
2382If Exim is called under the name 'mailq', it behaves as if the option %-bp%
2383were present before any other options.
2384The %-bp% option requests a listing of the contents of the mail queue on the
2385standard output.
2386This feature is for compatibility with some systems that contain a command of
2387that name in one of the standard libraries, symbolically linked to
2388_/usr/sbin/sendmail_ or _/usr/lib/sendmail_.
2389
2390cindex:['rsmtp']
2391If Exim is called under the name 'rsmtp' it behaves as if the option %-bS%
2392were present before any other options, for compatibility with Smail. The %-bS%
2393option is used for reading in a number of messages in batched SMTP format.
2394
2395cindex:['rmail']
2396If Exim is called under the name 'rmail' it behaves as if the %-i% and
2397%-oee% options were present before any other options, for compatibility with
2398Smail. The name 'rmail' is used as an interface by some UUCP systems.
2399
2400cindex:['runq']
2401cindex:[queue runner]
2402If Exim is called under the name 'runq' it behaves as if the option %-q% were
2403present before any other options, for compatibility with Smail. The %-q%
2404option causes a single queue runner process to be started.
2405
2406cindex:['newaliases']
2407cindex:[alias file,building]
2408cindex:[Sendmail compatibility,calling Exim as 'newaliases']
2409If Exim is called under the name 'newaliases' it behaves as if the option
2410%-bi% were present before any other options, for compatibility with Sendmail.
2411This option is used for rebuilding Sendmail's alias file. Exim does not have
2412the concept of a single alias file, but can be configured to run a given
2413command if called with the %-bi% option.
2414
2415
2416[[SECTtrustedadmin]]
2417Trusted and admin users
2418~~~~~~~~~~~~~~~~~~~~~~~
2419Some Exim options are available only to 'trusted users' and others are
2420available only to 'admin users'. In the description below, the phrases ``Exim
2421user'' and ``Exim group'' mean the user and group defined by EXIM_USER and
2422EXIM_GROUP in _Local/Makefile_ or set by the %exim_user% and
2423%exim_group% options. These do not necessarily have to use the name ``exim''.
2424
2425- cindex:[trusted user,definition of]
2426cindex:[user, trusted definition of]
2427The trusted users are root, the Exim user, any user listed in the
2428%trusted_users% configuration option, and any user whose current group or any
2429supplementary group is one of those listed in the %trusted_groups%
2430configuration option. Note that the Exim group is not automatically trusted.
2431+
2432cindex:[``From'' line]
2433cindex:[envelope sender]
2434Trusted users are always permitted to use the %-f% option or a leading ``From ''
2435line to specify the envelope sender of a message that is passed to Exim through
2436the local interface (see the %-bm% and %-f% options below). See the
2437%untrusted_set_sender% option for a way of permitting non-trusted users to
2438set envelope senders.
2439+
2440cindex:['From:' header line]
2441cindex:['Sender:' header line]
2442For a trusted user, there is never any check on the contents of the 'From:'
2443header line, and a 'Sender:' line is never added. Furthermore, any existing
2444'Sender:' line in incoming local (non-TCP/IP) messages is not removed.
2445+
2446Trusted users may also specify a host name, host address, interface address,
2447protocol name, ident value, and authentication data when submitting a message
2448locally. Thus, they are able to insert messages into Exim's queue locally that
2449have the characteristics of messages received from a remote host. Untrusted
2450users may in some circumstances use %-f%, but can never set the other values
2451that are available to trusted users.
2452
2453- cindex:[user, admin definition of]
2454cindex:[admin user,definition of]
2455The admin users are root, the Exim user, and any user that is a member of the
2456Exim group or of any group listed in the %admin_groups% configuration option.
2457The current group does not have to be one of these groups.
2458+
2459Admin users are permitted to list the queue, and to carry out certain
2460operations on messages, for example, to force delivery failures. It is also
2461necessary to be an admin user in order to see the full information provided by
2462the Exim monitor, and full debugging output.
2463+
2464By default, the use of the %-M%, %-q%, %-R%, and %-S% options to cause Exim
2465to attempt delivery of messages on its queue is restricted to admin users.
2466However, this restriction can be relaxed by setting the %prod_requires_admin%
2467option false (that is, specifying %no_prod_requires_admin%).
2468+
2469Similarly, the use of the %-bp% option to list all the messages in the queue
2470is restricted to admin users unless %queue_list_requires_admin% is set
2471false.
2472
2473
2474*Warning*: If you configure your system so that admin users are able to
2475edit Exim's configuration file, you are giving those users an easy way of
2476getting root. There is further discussion of this issue at the start of chapter
2477<<CHAPconf>>.
2478
2479
2480
2481
2482Command line options
2483~~~~~~~~~~~~~~~~~~~~
2484The command options are described in alphabetical order below.
2485
2486///
2487We insert a stylized DocBook comment here, to identify the start of the command
2488line options. This is for the benefit of the Perl script that automatically
2489creates a man page for the options.
2490///
2491
2492++++
2493<!-- === Start of command line options === -->
2494++++
2495
2496
2497*{hh}*::
2498oindex:[{hh}]
2499cindex:[options, command line; terminating]
2500This is a pseudo-option whose only purpose is to terminate the options and
2501therefore to cause subsequent command line items to be treated as arguments
2502rather than options, even if they begin with hyphens.
2503
2504*--help*::
2505oindex:[%{hh}help%]
2506This option causes Exim to output a few sentences stating what it is.
2507The same output is generated if the Exim binary is called with no options and
2508no arguments.
2509
2510*-B*<'type'>::
2511oindex:[%-B%]
2512cindex:[8-bit characters]
2513cindex:[Sendmail compatibility,8-bit characters]
2514This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2515clean; it ignores this option.
2516
2517*-bd*::
2518oindex:[%-bd%]
2519cindex:[daemon]
2520cindex:[SMTP listener]
2521cindex:[queue runner]
2522This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
2523the %-bd% option is combined with the %-q%<'time'> option, to specify that
2524the daemon should also initiate periodic queue runs.
2525+
2526The %-bd% option can be used only by an admin user. If either of the %-d%
2527(debugging) or %-v% (verifying) options are set, the daemon does not
2528disconnect from the controlling terminal. When running this way, it can be
2529stopped by pressing ctrl-C.
2530+
2531By default, Exim listens for incoming connections to the standard SMTP port on
2532all the host's running interfaces. However, it is possible to listen on other
2533ports, on multiple ports, and only on specific interfaces. Chapter
2534<<CHAPinterfaces>> contains a description of the options that control this.
2535+
2536When a listening daemon
2537cindex:[daemon,process id (pid)]
2538cindex:[pid (process id),of daemon]
2539is started without the use of %-oX% (that is, without overriding the normal
2540configuration), it writes its process id to a file called _exim-daemon.pid_ in
2541Exim's spool directory. This location can be overridden by setting
2542PID_FILE_PATH in _Local/Makefile_. The file is written while Exim is still
2543running as root.
2544+
2545When %-oX% is used on the command line to start a listening daemon, the
2546process id is not written to the normal pid file path. However, %-oP% can be
2547used to specify a path on the command line if a pid file is required.
2548+
2549The SIGHUP signal
2550cindex:[SIGHUP]
2551can be used to cause the daemon to re-exec itself. This should be done whenever
2552Exim's configuration file, or any file that is incorporated into it by means of
2553the %.include% facility, is changed, and also whenever a new version of Exim is
2554installed. It is not necessary to do this when other files that are referenced
2555from the configuration (for example, alias files) are changed, because these
2556are reread each time they are used.
2557
2558*-bdf*::
2559oindex:[%-bdf%]
2560This option has the same effect as %-bd% except that it never disconnects from
2561the controlling terminal, even when no debugging is specified.
2562
2563*-be*::
2564oindex:[%-be%]
2565cindex:[testing,string expansion]
2566cindex:[expansion,testing]
2567Run Exim in expansion testing mode. Exim discards its root privilege, to
2568prevent ordinary users from using this mode to read otherwise inaccessible
2569files. If no arguments are given, Exim runs interactively, prompting for lines
2570of data.
2571+
2572If Exim was built with USE_READLINE=yes in _Local/Makefile_, it tries
2573to load the %libreadline% library dynamically whenever the %-be% option is
2574used without command line arguments. If successful, it uses the 'readline()'
2575function, which provides extensive line-editing facilities, for reading the
2576test data. A line history is supported.
2577+
2578Long expansion expressions can be split over several lines by using backslash
2579continuations. As in Exim's run time configuration, whitespace at the start of
2580continuation lines is ignored. Each argument or data line is passed through the
2581string expansion mechanism, and the result is output. Variable values from the
2582configuration file (for example, $qualify_domain$) are available, but no
2583message-specific values (such as $domain$) are set, because no message is
2584being processed.
2585
2586*-bF*~<'filename'>::
2587oindex:[%-bF%]
2588cindex:[system filter,testing]
2589cindex:[testing,system filter]
2590This option is the same as %-bf% except that it assumes that the filter being
2591tested is a system filter. The additional commands that are available only in
2592system filters are recognized.
2593
2594*-bf*~<'filename'>::
2595oindex:[%-bf%]
2596cindex:[filter,testing]
2597cindex:[testing,filter file]
2598cindex:[forward file,testing]
2599cindex:[testing,forward file]
2600cindex:[Sieve filter,testing]
2601This option runs Exim in user filter testing mode; the file is the filter file
2602to be tested, and a test message must be supplied on the standard input. If
2603there are no message-dependent tests in the filter, an empty file can be
2604supplied.
2605+
2606If you want to test a system filter file, use %-bF% instead of %-bf%. You can
2607use both %-bF% and %-bf% on the same command, in order to
2608test a system filter and a user filter in the same run. For example:
2609
2610 exim -bF /system/filter -bf /user/filter </test/message
2611+
2612This is helpful when the system filter adds header lines or sets filter
2613variables that are used by the user filter.
2614+
2615If the test filter file does not begin with one of the special lines
2616
2617 # Exim filter
2618 # Sieve filter
2619+
2620it is taken to be a normal _.forward_ file, and is tested for validity under
2621that interpretation. See sections <<SECTitenonfilred>> to <<SECTspecitredli>> for a
2622description of the possible contents of non-filter redirection lists.
2623+
2624The result of an Exim command that uses %-bf%, provided no errors are
2625detected, is a list of the actions that Exim would try to take if presented
2626with the message for real. More details of filter testing are given in the
2627separate document entitled 'Exim's interfaces to mail filtering'.
2628+
2629When testing a filter file,
2630cindex:[``From'' line]
2631cindex:[envelope sender]
2632cindex:[%-f% option,for filter testing]
2633the envelope sender can be set by the %-f% option,
2634or by a ``From '' line at the start of the test message. Various parameters that
2635would normally be taken from the envelope recipient address of the message can
2636be set by means of additional command line options (see the next four options).
2637
2638*-bfd*~<'domain'>::
2639oindex:[%-bfd%]
2640This sets the domain of the recipient address when a filter file is being
2641tested by means of the %-bf% option. The default is the value of
2642$qualify_domain$.
2643
2644*-bfl*~<'local~part'>::
2645oindex:[%-bfl%]
2646This sets the local part of the recipient address when a filter file is being
2647tested by means of the %-bf% option. The default is the username of the
2648process that calls Exim. A local part should be specified with any prefix or
2649suffix stripped, because that is how it appears to the filter when a message is
2650actually being delivered.
2651
2652*-bfp*~<'prefix'>::
2653oindex:[%-bfp%]
2654This sets the prefix of the local part of the recipient address when a filter
2655file is being tested by means of the %-bf% option. The default is an empty
2656prefix.
2657
2658*-bfs*~<'suffix'>::
2659oindex:[%-bfs%]
2660This sets the suffix of the local part of the recipient address when a filter
2661file is being tested by means of the %-bf% option. The default is an empty
2662suffix.
2663
2664*-bh*~<'IP~address'>::
2665oindex:[%-bh%]
2666cindex:[testing,incoming SMTP]
2667cindex:[SMTP,testing incoming]
2668cindex:[testing,relay control]
2669cindex:[relaying,testing configuration]
2670cindex:[policy control,testing]
2671cindex:[debugging,%-bh% option]
2672This option runs a fake SMTP session as if from the given IP address, using the
2673standard input and output. The IP address may include a port number at the end,
2674after a full stop. For example:
2675
2676 exim -bh 10.9.8.7.1234
2677 exim -bh fe80::a00:20ff:fe86:a061.5678
2678+
2679When an IPv6 address is given, it is converted into canonical form. In the case
2680of the second example above, the value of $sender_host_address$ after
2681conversion to the canonical form is `fe80:0000:0000:0a00:20ff:fe86:a061.5678`.
2682+
2683Comments as to what is going on are written to the standard error file. These
2684include lines beginning with ``LOG'' for anything that would have been logged.
2685This facility is provided for testing configuration options for incoming
2686messages, to make sure they implement the required policy. For example, you can
2687test your relay controls using %-bh%.
2688+
2689*Warning 1*:
2690cindex:[RFC 1413]
2691You cannot test features of the configuration that rely on
2692ident (RFC 1413) callouts. These cannot be done when testing using
2693%-bh% because there is no incoming SMTP connection.
2694+
2695*Warning 2*: Address verification callouts (see section <<SECTcallver>>) are
2696also skipped when testing using %-bh%. If you want these callouts to occur,
2697use %-bhc% instead.
2698+
2699Messages supplied during the testing session are discarded, and nothing is
2700written to any of the real log files. There may be pauses when DNS (and other)
2701lookups are taking place, and of course these may time out. The %-oMi% option
2702can be used to specify a specific IP interface and port if this is important.
2703+
2704The 'exim_checkaccess' utility is a ``packaged'' version of %-bh% whose
2705output just states whether a given recipient address from a given host is
2706acceptable or not. See section <<SECTcheckaccess>>.
2707
2708*-bhc*~<'IP~address'>::
2709oindex:[%-bhc%]
2710This option operates in the same way as %-bh%, except that address
2711verification callouts are performed if required. This includes consulting and
2712updating the callout cache database.
2713
2714*-bi*::
2715oindex:[%-bi%]
2716cindex:[alias file,building]
2717cindex:[building alias file]
2718cindex:[Sendmail compatibility,%-bi% option]
2719Sendmail interprets the %-bi% option as a request to rebuild its alias file.
2720Exim does not have the concept of a single alias file, and so it cannot mimic
2721this behaviour. However, calls to _/usr/lib/sendmail_ with the %-bi% option
2722tend to appear in various scripts such as NIS make files, so the option must be
2723recognized.
2724+
2725If %-bi% is encountered, the command specified by the %bi_command%
2726configuration option is run, under the uid and gid of the caller of Exim. If
2727the %-oA% option is used, its value is passed to the command as an argument.
2728The command set by %bi_command% may not contain arguments. The command can use
2729the 'exim_dbmbuild' utility, or some other means, to rebuild alias files if
2730this is required. If the %bi_command% option is not set, calling Exim with
2731%-bi% is a no-op.
2732
2733*-bm*::
2734oindex:[%-bm%]
2735cindex:[local message reception]
2736This option runs an Exim receiving process that accepts an incoming,
2737locally-generated message on the current input. The recipients are given as the
2738command arguments (except when %-t% is also present -- see below). Each
2739argument can be a comma-separated list of RFC 2822 addresses. This is the
2740default option for selecting the overall action of an Exim call; it is assumed
2741if no other conflicting option is present.
2742+
2743If any addresses in the message are unqualified (have no domain), they are
2744qualified by the values of the %qualify_domain% or %qualify_recipient%
2745options, as appropriate. The %-bnq% option (see below) provides a way of
2746suppressing this for special cases.
2747+
2748Policy checks on the contents of local messages can be enforced by means of
2749the non-SMTP ACL. See chapter <<CHAPACL>> for details.
2750+
2751The return code
2752cindex:[return code,for %-bm%]
2753is zero if the message is successfully accepted. Otherwise, the
2754action is controlled by the %-oe'x'% option setting -- see below.
2755+
2756The format
2757cindex:[message,format]
2758cindex:[format,message]
2759cindex:[``From'' line]
2760cindex:[UUCP,``From'' line]
2761cindex:[Sendmail compatibility,``From'' line]
2762of the message must be as defined in RFC 2822, except that, for
2763compatibility with Sendmail and Smail, a line in one of the forms
2764
2765 From sender Fri Jan 5 12:55 GMT 1997
2766 From sender Fri, 5 Jan 97 12:55:01
2767+
2768(with the weekday optional, and possibly with additional text after the date)
2769is permitted to appear at the start of the message. There appears to be no
2770authoritative specification of the format of this line. Exim recognizes it by
2771matching against the regular expression defined by the %uucp_from_pattern%
2772option, which can be changed if necessary.
2773+
2774The
2775cindex:[%-f% option,overriding ``From'' line]
2776specified sender is treated as if it were given as the argument to the
2777%-f% option, but if a %-f% option is also present, its argument is used in
2778preference to the address taken from the message. The caller of Exim must be a
2779trusted user for the sender of a message to be set in this way.
2780
2781*-bnq*::
2782oindex:[%-bnq%]
2783cindex:[address qualification, suppressing]
2784By default, Exim automatically qualifies unqualified addresses (those
2785without domains) that appear in messages that are submitted locally (that
2786is, not over TCP/IP). This qualification applies both to addresses in
2787envelopes, and addresses in header lines. Sender addresses are qualified using
2788%qualify_domain%, and recipient addresses using %qualify_recipient% (which
2789defaults to the value of %qualify_domain%).
2790+
2791Sometimes, qualification is not wanted. For example, if %-bS% (batch SMTP) is
2792being used to re-submit messages that originally came from remote hosts after
2793content scanning, you probably do not want to qualify unqualified addresses in
2794header lines. (Such lines will be present only if you have not enabled a header
2795syntax check in the appropriate ACL.)
2796+
2797The %-bnq% option suppresses all qualification of unqualified addresses in
2798messages that originate on the local host. When this is used, unqualified
2799addresses in the envelope provoke errors (causing message rejection) and
2800unqualified addresses in header lines are left alone.
2801
2802
2803*-bP*::
2804oindex:[%-bP%]
2805cindex:[configuration options, extracting]
2806cindex:[options,configuration -- extracting]
2807If this option is given with no arguments, it causes the values of all Exim's
2808main configuration options to be written to the standard output. The values
2809of one or more specific options can be requested by giving their names as
2810arguments, for example:
2811
2812 exim -bP qualify_domain hold_domains
2813+
2814However, any option setting that is preceded by the word ``hide'' in the
2815configuration file is not shown in full, except to an admin user. For other
2816users, the output is as in this example:
2817
2818 mysql_servers = <value not displayable>
2819+
2820If %configure_file% is given as an argument, the name of the run time
2821configuration file is output.
2822If a list of configuration files was supplied, the value that is output here
2823is the name of the file that was actually used.
2824+
2825cindex:[daemon,process id (pid)]
2826cindex:[pid (process id),of daemon]
2827If %log_file_path% or %pid_file_path% are given, the names of the directories
2828where log files and daemon pid files are written are output, respectively. If
2829these values are unset, log files are written in a sub-directory of the spool
2830directory called %log%, and the pid file is written directly into the spool
2831directory.
2832+
2833If %-bP% is followed by a name preceded by `+`, for example,
2834
2835 exim -bP +local_domains
2836+
2837it searches for a matching named list of any type (domain, host, address, or
2838local part) and outputs what it finds.
2839+
2840If
2841cindex:[options,router -- extracting]
2842cindex:[options,transport -- extracting]
2843one of the words %router%, %transport%, or %authenticator% is given,
2844followed by the name of an appropriate driver instance, the option settings for
2845that driver are output. For example:
2846
2847 exim -bP transport local_delivery
2848+
2849The generic driver options are output first, followed by the driver's private
2850options. A list of the names of drivers of a particular type can be obtained by
2851using one of the words %router_list%, %transport_list%, or
2852%authenticator_list%, and a complete list of all drivers with their option
2853settings can be obtained by using %routers%, %transports%, or %authenticators%.
2854
2855
2856*-bp*::
2857oindex:[%-bp%]
2858cindex:[queue,listing messages on]
2859cindex:[listing,messages on the queue]
2860This option requests a listing of the contents of the mail queue on the
2861standard output. If the %-bp% option is followed by a list of message ids,
2862just those messages are listed. By default, this option can be used only by an
2863admin user. However, the %queue_list_requires_admin% option can be set false
2864to allow any user to see the queue.
2865+
2866Each message on the queue is displayed as in the following example:
2867
2868 25m 2.9K 0t5C6f-0000c8-00 <alice@wonderland.fict.example>
2869 red.king@looking-glass.fict.example
2870 <other addresses>
2871+
2872The
2873cindex:[message,size in queue listing]
2874cindex:[size,of message]
2875first line contains the length of time the message has been on the queue
2876(in this case 25 minutes), the size of the message (2.9K), the unique local
2877identifier for the message, and the message sender, as contained in the
2878envelope. For bounce messages, the sender address is empty, and appears as
2879``<>''. If the message was submitted locally by an untrusted user who overrode
2880the default sender address, the user's login name is shown in parentheses
2881before the sender address.
2882+
2883If
2884cindex:[frozen messages,in queue listing]
2885the message is frozen (attempts to deliver it are suspended) then the text
2886``\*\*\* frozen \*\*\*'' is displayed at the end of this line.
2887+
2888The recipients of the message (taken from the envelope, not the headers) are
2889displayed on subsequent lines. Those addresses to which the message has already
2890been delivered are marked with the letter D. If an original address gets
2891expanded into several addresses via an alias or forward file, the original is
2892displayed with a D only when deliveries for all of its child addresses are
2893complete.
2894
2895
2896*-bpa*::
2897oindex:[%-bpa%]
2898This option operates like %-bp%, but in addition it shows delivered addresses
2899that were generated from the original top level address(es) in each message by
2900alias or forwarding operations. These addresses are flagged with ``+D'' instead
2901of just ``D''.
2902
2903
2904*-bpc*::
2905oindex:[%-bpc%]
2906cindex:[queue,count of messages on]
2907This option counts the number of messages on the queue, and writes the total
2908to the standard output. It is restricted to admin users, unless
2909%queue_list_requires_admin% is set false.
2910
2911
2912*-bpr*::
2913oindex:[%-bpr%]
2914This option operates like %-bp%, but the output is not sorted into
2915chronological order of message arrival. This can speed it up when there are
2916lots of messages on the queue, and is particularly useful if the output is
2917going to be post-processed in a way that doesn't need the sorting.
2918
2919*-bpra*::
2920oindex:[%-bpra%]
2921This option is a combination of %-bpr% and %-bpa%.
2922
2923*-bpru*::
2924oindex:[%-bpru%]
2925This option is a combination of %-bpr% and %-bpu%.
2926
2927
2928*-bpu*::
2929oindex:[%-bpu%]
2930This option operates like %-bp% but shows only undelivered top-level addresses
2931for each message displayed. Addresses generated by aliasing or forwarding are
2932not shown, unless the message was deferred after processing by a router with
2933the %one_time% option set.
2934
2935
2936*-brt*::
2937oindex:[%-brt%]
2938cindex:[testing,retry configuration]
2939cindex:[retry,configuration testing]
2940This option is for testing retry rules, and it must be followed by up to three
2941arguments. It causes Exim to look for a retry rule that matches the values
2942and to write it to the standard output. For example:
2943
2944 exim -brt bach.comp.mus.example
2945 Retry rule: *.comp.mus.example F,2h,15m; F,4d,30m;
2946+
2947See chapter <<CHAPretry>> for a description of Exim's retry rules. The first
2948argument, which is required, can be a complete address in the form
2949'local_part@domain', or it can be just a domain name. The second argument is
2950an optional second domain name; if no retry rule is found for the first
2951argument, the second is tried. This ties in with Exim's behaviour when looking
2952for retry rules for remote hosts -- if no rule is found that matches the host,
2953one that matches the mail domain is sought. The final argument is the name of a
2954specific delivery error, as used in setting up retry rules, for example
2955``quota_3d''.
2956
2957*-brw*::
2958oindex:[%-brw%]
2959cindex:[testing,rewriting]
2960cindex:[rewriting,testing]
2961This option is for testing address rewriting rules, and it must be followed by
2962a single argument, consisting of either a local part without a domain, or a
2963complete address with a fully qualified domain. Exim outputs how this address
2964would be rewritten for each possible place it might appear. See chapter
2965<<CHAPrewrite>> for further details.
2966
2967*-bS*::
2968oindex:[%-bS%]
2969cindex:[SMTP,batched incoming]
2970cindex:[batched SMTP input]
2971This option is used for batched SMTP input, which is an alternative interface
2972for non-interactive local message submission. A number of messages can be
2973submitted in a single run. However, despite its name, this is not really SMTP
2974input. Exim reads each message's envelope from SMTP commands on the standard
2975input, but generates no responses. If the caller is trusted, or
2976%untrusted_set_sender% is set, the senders in the SMTP MAIL commands are
2977believed; otherwise the sender is always the caller of Exim.
2978+
2979The message itself is read from the standard input, in SMTP format (leading
2980dots doubled), terminated by a line containing just a single dot. An error is
2981provoked if the terminating dot is missing. A further message may then follow.
2982+
2983As for other local message submissions, the contents of incoming batch SMTP
2984messages can be checked using the non-SMTP ACL (see chapter <<CHAPACL>>).
2985Unqualified addresses are automatically qualified using %qualify_domain% and
2986%qualify_recipient%, as appropriate, unless the %-bnq% option is used.
2987+
2988Some other SMTP commands are recognized in the input. HELO and EHLO act
2989as RSET; VRFY, EXPN, ETRN, and HELP act as NOOP;
2990QUIT quits, ignoring the rest of the standard input.
2991+
2992cindex:[return code,for %-bS%]
2993If any error is encountered, reports are written to the standard output and
2994error streams, and Exim gives up immediately. The return code is 0 if no error
2995was detected; it is 1 if one or more messages were accepted before the error
2996was detected; otherwise it is 2.
2997+
2998More details of input using batched SMTP are given in section
2999<<SECTincomingbatchedSMTP>>.
3000
3001*-bs*::
3002oindex:[%-bs%]
3003cindex:[SMTP,local input]
3004cindex:[local SMTP input]
3005This option causes Exim to accept one or more messages by reading SMTP commands
3006on the standard input, and producing SMTP replies on the standard output. SMTP
3007policy controls, as defined in ACLs (see chapter <<CHAPACL>>) are applied.
3008Some user agents use this interface as a way of passing locally-generated
3009messages to the MTA.
3010+
3011In
3012cindex:[sender,source of]
3013this usage, if the caller of Exim is trusted, or %untrusted_set_sender% is
3014set, the senders of messages are taken from the SMTP MAIL commands.
3015Otherwise the content of these commands is ignored and the sender is set up as
3016the calling user. Unqualified addresses are automatically qualified using
3017%qualify_domain% and %qualify_recipient%, as appropriate, unless the %-bnq%
3018option is used.
3019+
3020cindex:[inetd]
3021The
3022%-bs% option is also used to run Exim from 'inetd', as an alternative to using
3023a listening daemon. Exim can distinguish the two cases by checking whether the
3024standard input is a TCP/IP socket. When Exim is called from 'inetd', the source
3025of the mail is assumed to be remote, and the comments above concerning senders
3026and qualification do not apply. In this situation, Exim behaves in exactly the
3027same way as it does when receiving a message via the listening daemon.
3028
3029*-bt*::
3030oindex:[%-bt%]
3031cindex:[testing,addresses]
3032cindex:[address,testing]
3033This option runs Exim in address testing mode, in which each argument is taken
3034as an address to be tested for deliverability. The results are written to the
3035standard output. If a test fails, and the caller is not an admin user, no
3036details of the failure are output, because these might contain sensitive
3037information such as usernames and passwords for database lookups.
3038+
3039If no arguments are given, Exim runs in an interactive manner, prompting with a
3040right angle bracket for addresses to be tested.
3041+
3042Unlike the %-be% test option, you cannot arrange for Exim to use the
3043'readline()' function, because it is running as 'root' and there are
3044security issues.
3045+
3046Each address is handled as if it were the recipient address of a message
3047(compare the %-bv% option). It is passed to the routers and the result is
3048written to the standard output. However, any router that has
3049%no_address_test% set is bypassed. This can make %-bt% easier to use for
3050genuine routing tests if your first router passes everything to a scanner
3051program.
3052+
3053The
3054cindex:[return code,for %-bt%]
3055return code is 2 if any address failed outright; it is 1 if no address
3056failed outright but at least one could not be resolved for some reason. Return
3057code 0 is given only when all addresses succeed.
3058+
3059*Warning*: %-bt% can only do relatively simple testing. If any of the
3060routers in the configuration makes any tests on the sender address of a
3061message,
3062cindex:[%-f% option,for address testing]
3063you can use the %-f% option to set an appropriate sender when running
3064%-bt% tests. Without it, the sender is assumed to be the calling user at the
3065default qualifying domain. However, if you have set up (for example) routers
3066whose behaviour depends on the contents of an incoming message, you cannot test
3067those conditions using %-bt%. The %-N% option provides a possible way of
3068doing such tests.
3069
3070*-bV*::
3071oindex:[%-bV%]
3072cindex:[version number of Exim, verifying]
3073This option causes Exim to write the current version number, compilation
3074number, and compilation date of the 'exim' binary to the standard output.
3075It also lists the DBM library this is being used, the optional modules (such as
3076specific lookup types), the drivers that are included in the binary, and the
3077name of the run time configuration file that is in use.
3078+
3079As part of its operation, %-bV% causes Exim to read and syntax check its
3080configuration file. However, this is a static check only. It cannot check
3081values that are to be expanded. For example, although a misspelt ACL verb is
3082detected, an error in the verb's arguments is not. You cannot rely on %-bV%
3083alone to discover (for example) all the typos in the configuration; some
3084realistic testing is needed. The %-bh% and %-N% options provide more dynamic
3085testing facilities.
3086
3087*-bv*::
3088oindex:[%-bv%]
3089cindex:[verifying address, using %-bv%]
3090cindex:[address,verification]
3091This option runs Exim in address verification mode, in which each argument is
3092taken as an address to be verified. During normal operation, verification
3093happens mostly as a consequence processing a %verify% condition in an ACL (see
3094chapter <<CHAPACL>>). If you want to test an entire ACL, see the %-bh% option.
3095+
3096If verification fails, and the caller is not an admin user, no details of the
3097failure are output, because these might contain sensitive information such as
3098usernames and passwords for database lookups.
3099+
3100If no arguments are given, Exim runs in an interactive manner, prompting with a
3101right angle bracket for addresses to be verified.
3102+
3103Unlike the %-be% test option, you cannot arrange for Exim to use the
3104'readline()' function, because it is running as 'exim' and there are
3105security issues.
3106+
3107Verification differs from address testing (the %-bt% option) in that routers
3108that have %no_verify% set are skipped, and if the address is accepted by a
3109router that has %fail_verify% set, verification fails. The address is verified
3110as a recipient if %-bv% is used; to test verification for a sender address,
3111%-bvs% should be used.
3112+
3113If the %-v% option is not set, the output consists of a single line for each
3114address, stating whether it was verified or not, and giving a reason in the
3115latter case. Otherwise, more details are given of how the address has been
3116handled, and in the case of address redirection, all the generated addresses
3117are also considered. Without %-v%, generating more than one address by
3118redirection causes verification to end sucessfully.
3119+
3120The
3121cindex:[return code,for %-bv%]
3122return code is 2 if any address failed outright; it is 1 if no address
3123failed outright but at least one could not be resolved for some reason. Return
3124code 0 is given only when all addresses succeed.
3125+
3126If any of the routers in the configuration makes any tests on the sender
3127address of a message, you should use the %-f% option to set an appropriate
3128sender when running %-bv% tests. Without it, the sender is assumed to be the
3129calling user at the default qualifying domain.
3130
3131*-bvs*::
3132oindex:[%-bvs%]
3133This option acts like %-bv%, but verifies the address as a sender rather
3134than a recipient address. This affects any rewriting and qualification that
3135might happen.
3136
3137*-C*~<'filelist'>::
3138oindex:[%-C%]
3139cindex:[configuration file,alternate]
3140cindex:[CONFIGURE_FILE]
3141cindex:[alternate configuration file]
3142This option causes Exim to find the run time configuration file from the given
3143list instead of from the list specified by the CONFIGURE_FILE
3144compile-time setting. Usually, the list will consist of just a single file
3145name, but it can be a colon-separated list of names. In this case, the first
3146file that exists is used. Failure to open an existing file stops Exim from
3147proceeding any further along the list, and an error is generated.
3148+
3149When this option is used by a caller other than root or the Exim user, and the
3150list is different from the compiled-in list, Exim gives up its root privilege
3151immediately, and runs with the real and effective uid and gid set to those of
3152the caller. However, if ALT_CONFIG_ROOT_ONLY is defined in
3153_Local/Makefile_, root privilege is retained for %-C% only if the caller of
3154Exim is root.
3155+
3156That is, the Exim user is no longer privileged in this regard. This build-time
3157option is not set by default in the Exim source distribution tarbundle.
3158However, if you are using a ``packaged'' version of Exim (source or binary), the
3159packagers might have enabled it.
3160+
3161Setting ALT_CONFIG_ROOT_ONLY locks out the possibility of testing a
3162configuration using %-C% right through message reception and delivery, even if
3163the caller is root. The reception works, but by that time, Exim is running as
3164the Exim user, so when it re-execs to regain privilege for the delivery, the
3165use of %-C% causes privilege to be lost. However, root can test reception and
3166delivery using two separate commands (one to put a message on the queue, using
3167%-odq%, and another to do the delivery, using %-M%).
3168+
3169If ALT_CONFIG_PREFIX is defined _in Local/Makefile_, it specifies a
3170prefix string with which any file named in a %-C% command line option
3171must start. In addition, the file name must not contain the sequence `/../`.
3172However, if the value of the %-C% option is identical to the value of
3173CONFIGURE_FILE in _Local/Makefile_, Exim ignores %-C% and proceeds as
3174usual. There is no default setting for ALT_CONFIG_PREFIX; when it is
3175unset, any file name can be used with %-C%.
3176+
3177ALT_CONFIG_PREFIX can be used to confine alternative configuration files
3178to a directory to which only root has access. This prevents someone who has
3179broken into the Exim account from running a privileged Exim with an arbitrary
3180configuration file.
3181+
3182The %-C% facility is useful for ensuring that configuration files are
3183syntactically correct, but cannot be used for test deliveries, unless the
3184caller is privileged, or unless it is an exotic configuration that does not
3185require privilege. No check is made on the owner or group of the files
3186specified by this option.
3187
3188*-D*<'macro'>=<'value'>::
3189oindex:[%-D%]
3190cindex:[macro,setting on command line]
3191This option can be used to override macro definitions in the configuration file
3192(see section <<SECTmacrodefs>>). However, like %-C%, if it is used by an
3193unprivileged caller, it causes Exim to give up its root privilege.
3194If DISABLE_D_OPTION is defined in _Local/Makefile_, the use of %-D% is
3195completely disabled, and its use causes an immediate error exit.
3196+
3197The entire option (including equals sign if present) must all be within one
3198command line item. %-D% can be used to set the value of a macro to the empty
3199string, in which case the equals sign is optional. These two commands are
3200synonymous:
3201
3202 exim -DABC ...
3203 exim -DABC= ...
3204+
3205To include spaces in a macro definition item, quotes must be used. If you use
3206quotes, spaces are permitted around the macro name and the equals sign. For
3207example:
3208
3209 exim '-D ABC = something' ...
3210+
3211%-D% may be repeated up to 10 times on a command line.
3212
3213*-d*<'debug~options'>::
3214oindex:[%-d%]
3215cindex:[debugging,list of selectors]
3216cindex:[debugging,%-d% option]
3217This option causes debugging information to be written to the standard
3218error stream. It is restricted to admin users because debugging output may show
3219database queries that contain password information. Also, the details of users'
3220filter files should be protected. When %-d% is used, %-v% is assumed. If
3221%-d% is given on its own, a lot of standard debugging data is output. This can
3222be reduced, or increased to include some more rarely needed information, by
3223following %-d% with a string made up of names preceded by plus or minus
3224characters. These add or remove sets of debugging data, respectively. For
3225example, %-d+filter% adds filter debugging, whereas %-d-all+filter% selects
3226only filter debugging. The available debugging categories are:
3227+
3228&&&
3229`acl ` ACL interpretation
3230`auth ` authenticators
3231`deliver ` general delivery logic
3232`dns ` DNS lookups (see also resolver)
3233`dnsbl ` DNS black list (aka RBL) code
3234`exec ` arguments for ^^execv()^^ calls
3235`expand ` detailed debugging for string expansions
3236`filter ` filter handling
3237`hints_lookup ` hints data lookups
3238`host_lookup ` all types of name-to-IP address handling
3239`ident ` ident lookup
3240`interface ` lists of local interfaces
3241`lists ` matching things in lists
3242`load ` system load checks
3243`local_scan ` can be used by ^^local_scan()^^ (see chapter <<CHAPlocalscan>>)
3244`lookup ` general lookup code and all lookups
3245`memory ` memory handling
3246`pid ` add pid to debug output lines
3247`process_info ` setting info for the process log
3248`queue_run ` queue runs
3249`receive ` general message reception logic
3250`resolver ` turn on the DNS resolver's debugging output
3251`retry ` retry handling
3252`rewrite ` address rewriting
3253`route ` address routing
3254`timestamp ` add timestamp to debug output lines
3255`tls ` TLS logic
3256`transport ` transports
3257`uid ` changes of uid/gid and looking up uid/gid
3258`verify ` address verification logic
3259`all ` all of the above, and also %-v%
3260&&&
3261+
3262The
3263cindex:[resolver, debugging output]
3264cindex:[DNS resolver, debugging output]
3265`resolver` option produces output only if the DNS resolver was compiled
3266with DEBUG enabled. This is not the case in some operating systems. Also,
3267unfortunately, debugging output from the DNS resolver is written to stdout
3268rather than stderr.
3269+
3270The default (%-d% with no argument) omits `expand`, `filter`,
3271`interface`, `load`, `memory`, `pid`, `resolver`, and `timestamp`.
3272However, the `pid` selector is forced when debugging is turned on for a
3273daemon, which then passes it on to any re-executed Exims. Exim also
3274automatically adds the pid to debug lines when several remote deliveries are
3275run in parallel.
3276+
3277The `timestamp` selector causes the current time to be inserted at the start
3278of all debug output lines. This can be useful when trying to track down delays
3279in processing.
3280+
3281If the %debug_print% option is set in any driver, it produces output whenever
3282any debugging is selected, or if %-v% is used.
3283
3284*-dd*<'debug~options'>::
3285oindex:[%-dd%]
3286This option behaves exactly like %-d% except when used on a command that
3287starts a daemon process. In that case, debugging is turned off for the
3288subprocesses that the daemon creates. Thus, it is useful for monitoring the
3289behaviour of the daemon without creating as much output as full debugging does.
3290
3291*-dropcr*::
3292oindex:[%-dropcr%]
3293This is an obsolete option that is now a no-op. It used to affect the way Exim
3294handled CR and LF characters in incoming messages. What happens now is
3295described in section <<SECTlineendings>>.
3296
3297*-E*::
3298oindex:[%-E%]
3299cindex:[bounce message,generating]
3300This option specifies that an incoming message is a locally-generated delivery
3301failure report. It is used internally by Exim when handling delivery failures
3302and is not intended for external use. Its only effect is to stop Exim
3303generating certain messages to the postmaster, as otherwise message cascades
3304could occur in some situations. As part of the same option, a message id may
3305follow the characters %-E%. If it does, the log entry for the receipt of the
3306new message contains the id, following ``R='', as a cross-reference.
3307
3308*-e*'x'::
3309oindex:[%-e'x'%]
3310There are a number of Sendmail options starting with %-oe% which seem to be
3311called by various programs without the leading %o% in the option. For example,
3312the %vacation% program uses %-eq%. Exim treats all options of the form
3313%-e'x'% as synonymous with the corresponding %-oe'x'% options.
3314
3315*-F*~<'string'>::
3316oindex:[%-F%]
3317cindex:[sender,name]
3318cindex:[name,of sender]
3319This option sets the sender's full name for use when a locally-generated
3320message is being accepted. In the absence of this option, the user's 'gecos'
3321entry from the password data is used. As users are generally permitted to alter
3322their 'gecos' entries, no security considerations are involved. White space
3323between %-F% and the <'string'> is optional.
3324
3325*-f*~<'address'>::
3326oindex:[%-f%]
3327cindex:[sender,address]
3328cindex:[address,sender]
3329cindex:[trusted user]
3330cindex:[envelope sender]
3331cindex:[user,trusted]
3332This option sets the address of the envelope sender of a locally-generated
3333message (also known as the return path). The option can normally be used only
3334by a trusted user, but %untrusted_set_sender% can be set to allow untrusted
3335users to use it.
3336+
3337Processes running as root or the Exim user are always trusted. Other
3338trusted users are defined by the %trusted_users% or %trusted_groups% options.
3339In the absence of %-f%, or if the caller is not trusted, the sender of a local
3340message is set to the caller's login name at the default qualify domain.
3341+
3342There is one exception to the restriction on the use of %-f%: an empty sender
3343can be specified by any user, trusted or not, to create a message that can
3344never provoke a bounce. An empty sender can be specified either as an empty
3345string, or as a pair of angle brackets with nothing between them, as in these
3346examples of shell commands:
3347
3348 exim -f '<>' user@domain
3349 exim -f "" user@domain
3350+
3351In addition, the use of %-f% is not restricted when testing a filter file with
3352%-bf% or when testing or verifying addresses using the %-bt% or %-bv%
3353options.
3354+
3355Allowing untrusted users to change the sender address does not of itself make
3356it possible to send anonymous mail. Exim still checks that the 'From:' header
3357refers to the local user, and if it does not, it adds a 'Sender:' header,
3358though this can be overridden by setting %no_local_from_check%.
3359+
3360White
3361cindex:[``From'' line]
3362space between %-f% and the <'address'> is optional (that is, they can be given
3363as two arguments or one combined argument). The sender of a locally-generated
3364message can also be set (when permitted) by an initial ``From '' line in the
3365message -- see the description of %-bm% above -- but if %-f% is also present,
3366it overrides ``From''.
3367
3368*-G*::
3369oindex:[%-G%]
3370cindex:[Sendmail compatibility,%-G% option ignored]
3371This is a Sendmail option which is ignored by Exim.
3372
3373*-h*~<'number'>::
3374oindex:[%-h%]
3375cindex:[Sendmail compatibility,%-h% option ignored]
3376This option is accepted for compatibility with Sendmail, but has no effect. (In
3377Sendmail it overrides the ``hop count'' obtained by counting 'Received:'
3378headers.)
3379
3380*-i*::
3381oindex:[%-i%]
3382cindex:[Solaris,'mail' command]
3383cindex:[dot in incoming, non-SMTP message]
3384This option, which has the same effect as %-oi%, specifies that a dot on a line
3385by itself should not terminate an incoming, non-SMTP message. I can find no
3386documentation for this option in Solaris 2.4 Sendmail, but the 'mailx' command
3387in Solaris 2.4 uses it. See also %-ti%.
3388
3389*-M*~<'message~id'>~<'message~id'>~...::
3390oindex:[%-M%]
3391cindex:[forcing delivery]
3392cindex:[delivery,forcing attempt]
3393cindex:[frozen messages,forcing delivery]
3394This option requests Exim to run a delivery attempt on each message in turn. If
3395any of the messages are frozen, they are automatically thawed before the
3396delivery attempt. The settings of %queue_domains%, %queue_smtp_domains%, and
3397%hold_domains% are ignored.
3398+
3399Retry
3400cindex:[hints database,overriding retry hints]
3401hints for any of the addresses are overridden -- Exim tries to deliver even if
3402the normal retry time has not yet been reached. This option requires the caller
3403to be an admin user. However, there is an option called %prod_requires_admin%
3404which can be set false to relax this restriction (and also the same requirement
3405for the %-q%, %-R%, and %-S% options).
3406
3407*-Mar*~<'message~id'>~<'address'>~<'address'>~...::
3408oindex:[%-Mar%]
3409cindex:[message,adding recipients]
3410cindex:[recipient,adding]
3411This option requests Exim to add the addresses to the list of recipients of the
3412message (``ar'' for ``add recipients''). The first argument must be a message id,
3413and the remaining ones must be email addresses. However, if the message is
3414active (in the middle of a delivery attempt), it is not altered. This option
3415can be used only by an admin user.
3416
3417*-MC*~<'transport'>~<'hostname'>~<'sequence~number'>~<'message~id'>::
3418oindex:[%-MC%]
3419cindex:[SMTP,passed connection]
3420cindex:[SMTP,multiple deliveries]
3421cindex:[multiple SMTP deliveries]
3422This option is not intended for use by external callers. It is used internally
3423by Exim to invoke another instance of itself to deliver a waiting message using
3424an existing SMTP connection, which is passed as the standard input. Details are
3425given in chapter <<CHAPSMTP>>. This must be the final option, and the caller must
3426be root or the Exim user in order to use it.
3427
3428*-MCA*::
3429oindex:[%-MCA%]
3430This option is not intended for use by external callers. It is used internally
3431by Exim in conjunction with the %-MC% option. It signifies that the connection
3432to the remote host has been authenticated.
3433
3434*-MCP*::
3435oindex:[%-MCP%]
3436This option is not intended for use by external callers. It is used internally
3437by Exim in conjunction with the %-MC% option. It signifies that the server to
3438which Exim is connected supports pipelining.
3439
3440*-MCQ*~<'process~id'>~<'pipe~fd'>::
3441oindex:[%-MCQ%]
3442This option is not intended for use by external callers. It is used internally
3443by Exim in conjunction with the %-MC% option when the original delivery was
3444started by a queue runner. It passes on the process id of the queue runner,
3445together with the file descriptor number of an open pipe. Closure of the pipe
3446signals the final completion of the sequence of processes that are passing
3447messages through the same SMTP connection.
3448
3449*-MCS*::
3450oindex:[%-MCS%]
3451This option is not intended for use by external callers. It is used internally
3452by Exim in conjunction with the %-MC% option, and passes on the fact that the
3453SMTP SIZE option should be used on messages delivered down the existing
3454connection.
3455
3456*-MCT*::
3457oindex:[%-MCT%]
3458This option is not intended for use by external callers. It is used internally
3459by Exim in conjunction with the %-MC% option, and passes on the fact that the
3460host to which Exim is connected supports TLS encryption.
3461
3462*-Mc*~<'message~id'>~<'message~id'>~...::
3463oindex:[%-Mc%]
3464cindex:[hints database,not overridden by %-Mc%]
3465cindex:[delivery,manually started -- not forced]
3466This option requests Exim to run a delivery attempt on each message in turn,
3467but unlike the %-M% option, it does check for retry hints, and respects any
3468that are found. This option is not very useful to external callers. It is
3469provided mainly for internal use by Exim when it needs to re-invoke itself in
3470order to regain root privilege for a delivery (see chapter <<CHAPsecurity>>).
3471However, %-Mc% can be useful when testing, in order to run a delivery that
3472respects retry times and other options such as %hold_domains% that are
3473overridden when %-M% is used. Such a delivery does not count as a queue run.
3474If you want to run a specific delivery as if in a queue run, you should use
3475%-q% with a message id argument. A distinction between queue run deliveries
3476and other deliveries is made in one or two places.
3477
3478*-Mes*~<'message~id'>~<'address'>::
3479oindex:[%-Mes%]
3480cindex:[message,changing sender]
3481cindex:[sender,changing]
3482This option requests Exim to change the sender address in the message to the
3483given address, which must be a fully qualified address or ``<>'' (``es'' for ``edit
3484sender''). There must be exactly two arguments. The first argument must be a
3485message id, and the second one an email address. However, if the message is
3486active (in the middle of a delivery attempt), its status is not altered. This
3487option can be used only by an admin user.
3488
3489*-Mf*~<'message~id'>~<'message~id'>~...::
3490oindex:[%-Mf%]
3491cindex:[freezing messages]
3492cindex:[message,manually freezing]
3493This option requests Exim to mark each listed message as ``frozen''. This
3494prevents any delivery attempts taking place until the message is ``thawed'',
3495either manually or as a result of the %auto_thaw% configuration option.
3496However, if any of the messages are active (in the middle of a delivery
3497attempt), their status is not altered. This option can be used only by an admin
3498user.
3499
3500*-Mg*~<'message~id'>~<'message~id'>~...::
3501oindex:[%-Mg%]
3502cindex:[giving up on messages]
3503cindex:[message,abandoning delivery attempts]
3504cindex:[delivery,abandoning further attempts]
3505This option requests Exim to give up trying to deliver the listed messages,
3506including any that are frozen. However, if any of the messages are active,
3507their status is not altered. For non-bounce messages, a delivery error message
3508is sent to the sender, containing the text ``cancelled by administrator''.
3509Bounce messages are just discarded. This option can be used only by an admin
3510user.
3511
3512*-Mmad*~<'message~id'>~<'message~id'>~...::
3513oindex:[%-Mmad%]
3514cindex:[delivery,cancelling all]
3515This option requests Exim to mark all the recipient addresses in the messages
3516as already delivered (``mad'' for ``mark all delivered''). However, if any
3517message is active (in the middle of a delivery attempt), its status is not
3518altered. This option can be used only by an admin user.
3519
3520*-Mmd*~<'message~id'>~<'address'>~<'address'>~...::
3521oindex:[%-Mmd%]
3522cindex:[delivery,cancelling by address]
3523cindex:[recipient,removing]
3524cindex:[removing recipients]
3525This option requests Exim to mark the given addresses as already delivered
3526(``md'' for ``mark delivered''). The first argument must be a message id, and
3527the remaining ones must be email addresses. These are matched to recipient
3528addresses in the message in a case-sensitive manner. If the message is active
3529(in the middle of a delivery attempt), its status is not altered. This option
3530can be used only by an admin user.
3531
3532*-Mrm*~<'message~id'>~<'message~id'>~...::
3533oindex:[%-Mrm%]
3534cindex:[removing messages]
3535cindex:[abandoning mail]
3536cindex:[message,manually discarding]
3537This option requests Exim to remove the given messages from the queue. No
3538bounce messages are sent; each message is simply forgotten. However, if any of
3539the messages are active, their status is not altered. This option can be used
3540only by an admin user or by the user who originally caused the message to be
3541placed on the queue.
3542
3543*-Mt*~<'message~id'>~<'message~id'>~...::
3544oindex:[%-Mt%]
3545cindex:[thawing messages]
3546cindex:[unfreezing messages]
3547cindex:[frozen messages,thawing]
3548cindex:[message,thawing frozen]
3549This option requests Exim to ``thaw'' any of the listed messages that are
3550``frozen'', so that delivery attempts can resume. However, if any of the messages
3551are active, their status is not altered. This option can be used only by an
3552admin user.
3553
3554*-Mvb*~<'message~id'>::
3555oindex:[%-Mvb%]
3556cindex:[listing,message body]
3557cindex:[message,listing body of]
3558This option causes the contents of the message body (-D) spool file to be
3559written to the standard output. This option can be used only by an admin user.
3560
3561*-Mvh*~<'message~id'>::
3562oindex:[%-Mvh%]
3563cindex:[listing,message headers]
3564cindex:[header lines,listing]
3565cindex:[message,listing header lines]
3566This option causes the contents of the message headers (-H) spool file to be
3567written to the standard output. This option can be used only by an admin user.
3568
3569*-Mvl*~<'message~id'>::
3570oindex:[%-Mvl%]
3571cindex:[listing,message log]
3572cindex:[message,listing message log]
3573This option causes the contents of the message log spool file to be written to
3574the standard output. This option can be used only by an admin user.
3575
3576*-m*::
3577oindex:[%-m%]
3578This is apparently a synonym for %-om% that is accepted by Sendmail, so Exim
3579treats it that way too.
3580
3581*-N*::
3582oindex:[%-N%]
3583cindex:[debugging,%-N% option]
3584cindex:[debugging,suppressing delivery]
3585This is a debugging option that inhibits delivery of a message at the transport
3586level. It implies %-v%. Exim goes through many of the motions of delivery --
3587it just doesn't actually transport the message, but instead behaves as if it
3588had successfully done so. However, it does not make any updates to the retry
3589database, and the log entries for deliveries are flagged with ``\*>'' rather
3590than ``=>''.
3591+
3592Because %-N% discards any message to which it applies, only root or the Exim
3593user are allowed to use it with %-bd%, %-q%, %-R% or %-M%. In other words,
3594an ordinary user can use it only when supplying an incoming message to which it
3595will apply. Although transportation never fails when %-N% is set, an address
3596may be deferred because of a configuration problem on a transport, or a routing
3597problem. Once %-N% has been used for a delivery attempt, it sticks to the
3598message, and applies to any subsequent delivery attempts that may happen for
3599that message.
3600
3601*-n*::
3602oindex:[%-n%]
3603cindex:[Sendmail compatibility,%-n% option ignored]
3604This option is interpreted by Sendmail to mean ``no aliasing''. It is ignored by
3605Exim.
3606
3607*-O*~<'data'>::
3608oindex:[%-O%]
3609This option is interpreted by Sendmail to mean `set option`. It is ignored by
3610Exim.
3611
3612*-oA*~<'file~name'>::
3613oindex:[%-oA%]
3614cindex:[Sendmail compatibility,%-oA% option]
3615This option is used by Sendmail in conjunction with %-bi% to specify an
3616alternative alias file name. Exim handles %-bi% differently; see the
3617description above.
3618
3619*-oB*~<'n'>::
3620oindex:[%-oB%]
3621cindex:[SMTP,passed connection]
3622cindex:[SMTP,multiple deliveries]
3623cindex:[multiple SMTP deliveries]
3624This is a debugging option which limits the maximum number of messages that can
3625be delivered down one SMTP connection, overriding the value set in any ^smtp^
3626transport. If <'n'> is omitted, the limit is set to 1.
3627
3628*-odb*::
3629oindex:[%-odb%]
3630cindex:[background delivery]
3631cindex:[delivery,in the background]
3632This option applies to all modes in which Exim accepts incoming messages,
3633including the listening daemon. It requests ``background'' delivery of such
3634messages, which means that the accepting process automatically starts a
3635delivery process for each message received, but does not wait for the delivery
3636processes to finish.
3637+
3638When all the messages have been received, the reception process exits,
3639leaving the delivery processes to finish in their own time. The standard output
3640and error streams are closed at the start of each delivery process.
3641This is the default action if none of the %-od% options are present.
3642+
3643If one of the queueing options in the configuration file
3644(%queue_only% or %queue_only_file%, for example) is in effect, %-odb%
3645overrides it if %queue_only_override% is set true, which is the default
3646setting. If %queue_only_override% is set false, %-odb% has no effect.
3647
3648*-odf*::
3649oindex:[%-odf%]
3650cindex:[foreground delivery]
3651cindex:[delivery,in the foreground]
3652This option requests ``foreground'' (synchronous) delivery when Exim has accepted
3653a locally-generated message. (For the daemon it is exactly the same as
3654%-odb%.) A delivery process is automatically started to deliver the
3655message, and Exim waits for it to complete before proceeding.
3656+
3657The original Exim reception process does not finish until the delivery
3658process for the final message has ended. The standard error stream is left open
3659during deliveries.
3660+
3661However, like %-odb%, this option has no effect if %queue_only_override% is
3662false and one of the queueing options in the configuration file is in effect.
3663+
3664If there is a temporary delivery error during foreground delivery, the
3665message is left on the queue for later delivery, and the original reception
3666process exists. See chapter <<CHAPnonqueueing>> for a way of setting up a
3667restricted configuration that never queues messages.
3668
3669
3670*-odi*::
3671oindex:[%-odi%]
3672This option is synonymous with %-odf%. It is provided for compatibility with
3673Sendmail.
3674
3675*-odq*::
3676oindex:[%-odq%]
3677cindex:[non-immediate delivery]
3678cindex:[delivery,suppressing immediate]
3679cindex:[queueing incoming messages]
3680This option applies to all modes in which Exim accepts incoming messages,
3681including the listening daemon. It specifies that the accepting process should
3682not automatically start a delivery process for each message received. Messages
3683are placed on the queue, and remain there until a subsequent queue runner
3684process encounters them. There are several configuration options (such as
3685%queue_only%) that can be used to queue incoming messages under certain
3686conditions. This option overrides all of them and also %-odqs%. It always
3687forces queueing.
3688
3689*-odqs*::
3690oindex:[%-odqs%]
3691cindex:[SMTP,delaying delivery]
3692This option is a hybrid between %-odb%/%-odi% and %-odq%.
3693However, like %-odb% and %-odi%, this option has no effect if
3694%queue_only_override% is false and one of the queueing options in the
3695configuration file is in effect.
3696+
3697When %-odqs% does operate, a delivery process is started for each incoming
3698message, in the background by default, but in the foreground if %-odi% is also
3699present. The recipient addresses are routed, and local deliveries are done in
3700the normal way. However, if any SMTP deliveries are required, they are not done
3701at this time, so the message remains on the queue until a subsequent queue
3702runner process encounters it. Because routing was done, Exim knows which
3703messages are waiting for which hosts, and so a number of messages for the same
3704host can be sent in a single SMTP connection. The %queue_smtp_domains%
3705configuration option has the same effect for specific domains. See also the
3706%-qq% option.
3707
3708*-oee*::
3709oindex:[%-oee%]
3710cindex:[error,reporting]
3711If an error is detected while a non-SMTP message is being received (for
3712example, a malformed address), the error is reported to the sender in a mail
3713message.
3714+
3715Provided
3716cindex:[return code,for %-oee%]
3717this error message is successfully sent, the Exim receiving process
3718exits with a return code of zero. If not, the return code is 2 if the problem
3719is that the original message has no recipients, or 1 any other error. This is
3720the default %-oe'x'% option if Exim is called as 'rmail'.
3721
3722*-oem*::
3723oindex:[%-oem%]
3724cindex:[error,reporting]
3725cindex:[return code,for %-oem%]
3726This is the same as %-oee%, except that Exim always exits with a non-zero
3727return code, whether or not the error message was successfully sent.
3728This is the default %-oe'x'% option, unless Exim is called as 'rmail'.
3729
3730*-oep*::
3731oindex:[%-oep%]
3732cindex:[error,reporting]
3733If an error is detected while a non-SMTP message is being received, the
3734error is reported by writing a message to the standard error file (stderr).
3735cindex:[return code,for %-oep%]
3736The return code is 1 for all errors.
3737
3738*-oeq*::
3739oindex:[%-oeq%]
3740cindex:[error,reporting]
3741This option is supported for compatibility with Sendmail, but has the same
3742effect as %-oep%.
3743
3744*-oew*::
3745oindex:[%-oew%]
3746cindex:[error,reporting]
3747This option is supported for compatibility with Sendmail, but has the same
3748effect as %-oem%.
3749
3750*-oi*::
3751oindex:[%-oi%]
3752cindex:[dot in incoming, non-SMTP message]
3753This option, which has the same effect as %-i%, specifies that a dot on a line
3754by itself should not terminate an incoming, non-SMTP message.
3755Otherwise, a single dot does terminate, though Exim does no special processing
3756for other lines that start with a dot.
3757This option is set by default if Exim is called as 'rmail'. See also %-ti%.
3758
3759*-oitrue*::
3760oindex:[%-oitrue%]
3761This option is treated as synonymous with %-oi%.
3762
3763*-oMa*~<'host~address'>::
3764oindex:[%-oMa%]
3765cindex:[sender host address, specifying for local message]
3766A number of options starting with %-oM% can be used to set values associated
3767with remote hosts on locally-submitted messages (that is, messages not received
3768over TCP/IP). These options can be used by any caller in conjunction with the
3769%-bh%, %-be%, %-bf%, %-bF%, %-bt%, or %-bv% testing options. In other
3770circumstances, they are ignored unless the caller is trusted.
3771+
3772The %-oMa% option sets the sender host address. This may include a port number
3773at the end, after a full stop (period). For example:
3774
3775 exim -bs -oMa 10.9.8.7.1234
3776+
3777An alternative syntax is to enclose the IP address in square brackets,
3778followed by a colon and the port number:
3779
3780 exim -bs -oMa [10.9.8.7]:1234
3781+
3782The IP address is placed in the $sender_host_address$ variable, and the
3783port, if present, in $sender_host_port$.
3784
3785*-oMaa*~<'name'>::
3786oindex:[%-oMaa%]
3787cindex:[authentication name, specifying for local message]
3788See %-oMa% above for general remarks about the %-oM% options. The %-oMaa%
3789option sets the value of $sender_host_authenticated$ (the authenticator
3790name). See chapter <<CHAPSMTPAUTH>> for a discussion of SMTP authentication.
3791
3792*-oMai*~<'string'>::
3793oindex:[%-oMai%]
3794cindex:[authentication id, specifying for local message]
3795See %-oMa% above for general remarks about the %-oM% options. The %-oMai%
3796option sets the value of $authenticated_id$ (the id that was authenticated).
3797This overrides the default value (the caller's login id) for messages from
3798local sources. See chapter <<CHAPSMTPAUTH>> for a discussion of authenticated
3799ids.
3800
3801*-oMas*~<'address'>::
3802oindex:[%-oMas%]
3803cindex:[authentication sender, specifying for local message]
3804See %-oMa% above for general remarks about the %-oM% options. The %-oMas%
3805option sets the authenticated sender value in $authenticated_sender$. It
3806overrides the sender address that is created from the caller's login id for
3807messages from local sources. See chapter <<CHAPSMTPAUTH>> for a discussion of
3808authenticated senders.
3809
3810*-oMi*~<'interface~address'>::
3811oindex:[%-oMi%]
3812cindex:[interface address, specifying for local message]
3813See %-oMa% above for general remarks about the %-oM% options. The %-oMi% option
3814sets the IP interface address value. A port number may be included, using the
3815same syntax as for %-oMa%. The interface address is placed in
3816$interface_address$ and the port number, if present, in $interface_port$.
3817
3818*-oMr*~<'protocol~name'>::
3819oindex:[%-oMr%]
3820cindex:[protocol,incoming -- specifying for local message]
3821See %-oMa% above for general remarks about the %-oM% options. The %-oMr% option
3822sets the received protocol value that is stored in $received_protocol$.
3823However, this applies only when %-bs% is not used. For interactive SMTP input
3824(%-bs%), the protocol is always ``local-'' followed by one of the standard SMTP
3825protocol names (see the description of $received_protocol$ in section
3826<<SECTexpvar>>). For %-bS% (batch SMTP) however, the protocol can be set by
3827<<%-oMr%.
3828
3829*-oMs*~<'host~name'>::
3830oindex:[%-oMs%]
3831cindex:[sender host name, specifying for local message]
3832See %-oMa% above for general remarks about the %-oM% options. The %-oMs% option
3833sets the sender host name in $sender_host_name$. When this option is present,
3834Exim does not attempt to look up a host name from an IP address; it uses the
3835name it is given.
3836
3837*-oMt*~<'ident~string'>::
3838oindex:[%-oMt%]
3839cindex:[sender ident string, specifying for local message]
3840See %-oMa% above for general remarks about the %-oM% options. The %-oMt% option
3841sets the sender ident value in $sender_ident$. The default setting for local
3842callers is the login id of the calling process.
3843
3844*-om*::
3845oindex:[%-om%]
3846cindex:[Sendmail compatibility,%-om% option ignored]
3847In Sendmail, this option means ``me too'', indicating that the sender of a
3848message should receive a copy of the message if the sender appears in an alias
3849expansion. Exim always does this, so the option does nothing.
3850
3851*-oo*::
3852oindex:[%-oo%]
3853cindex:[Sendmail compatibility,%-oo% option ignored]
3854This option is ignored. In Sendmail it specifies ``old style headers'', whatever
3855that means.
3856
3857*-oP*~<'path'>::
3858oindex:[%-oP%]
3859cindex:[pid (process id),of daemon]
3860cindex:[daemon,process id (pid)]
3861This option is useful only in conjunction with %-bd% or %-q% with a time
3862value. The option specifies the file to which the process id of the daemon is
3863written. When %-oX% is used with %-bd%, or when %-q% with a time is used
3864without %-bd%, this is the only way of causing Exim to write a pid file,
3865because in those cases, the normal pid file is not used.
3866
3867*-or*~<'time'>::
3868oindex:[%-or%]
3869cindex:[timeout,for non-SMTP input]
3870This option sets a timeout value for incoming non-SMTP messages. If it is not
3871set, Exim will wait forever for the standard input. The value can also be set
3872by the %receive_timeout% option. The format used for specifying times is
3873described in section <<SECTtimeformat>>.
3874
3875*-os*~<'time'>::
3876oindex:[%-os%]
3877cindex:[timeout,for SMTP input]
3878cindex:[SMTP timeout, input]
3879This option sets a timeout value for incoming SMTP messages. The timeout
3880applies to each SMTP command and block of data. The value can also be set by
3881the %smtp_receive_timeout% option; it defaults to 5 minutes. The format used
3882for specifying times is described in section <<SECTtimeformat>>.
3883
3884*-ov*::
3885oindex:[%-ov%]
3886This option has exactly the same effect as %-v%.
3887