Add maildirfolder_create_regex to appendfile.
[exim.git] / doc / doc-docbook / spec.xfpt
CommitLineData
4f578862 1. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.2 2006/04/04 14:03:49 ph10 Exp $
9b371988
PH
2.
3. /////////////////////////////////////////////////////////////////////////////
4. This is the primary source of the Exim Manual. It is an xfpt document that is
5. converted into DocBook XML for subsequent conversion into printing and online
6. formats. The markup used herein is "standard" xfpt markup, with some extras.
7. The markup is summarized in a file called Markup.txt.
8. /////////////////////////////////////////////////////////////////////////////
9
10.include stdflags
11.include stdmacs
12.docbook
13.book
14
15. /////////////////////////////////////////////////////////////////////////////
16. These definitions set some parameters and save some typing. Remember that
17. the <bookinfo> element must also be updated for each new edition.
18. /////////////////////////////////////////////////////////////////////////////
19
20.set ACL "access control lists (ACLs)"
4f578862
PH
21.set previousversion "4.60"
22.set version "4.61"
9b371988
PH
23
24
25. /////////////////////////////////////////////////////////////////////////////
26. Additional xfpt markup used by this document, over and above the default
27. provided in the xfpt library.
28. /////////////////////////////////////////////////////////////////////////////
29
30. --- Override the &$ flag to automatically insert a $ with the variable name
31
32.flag &$ $& "<varname>$" "</varname>"
33
34. --- Short flags for daggers in option headings. They will always be inside
35. --- an italic string, but we want the daggers to be roman.
36
37.flag &!! "</emphasis>&dagger;<emphasis>"
38.flag &!? "</emphasis>&Dagger;<emphasis>"
39
40. --- A macro for an Exim option definition heading, generating a one-line
41. --- table with four columns.
42
43.macro option
44.oindex "$1"
45.itable all 0 0 4 8* left 5* center 5* center 6* right
46.row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&"
47.endtable
48.endmacro
49
50. --- A macro for the common 2-column tables. The width of the first column
51. --- is suitable for the many tables at the start of the main options chapter;
52. --- the small number of other 2-column tables override it.
53
4f578862 54.macro table2 190pt 260pt
9b371988
PH
55.itable none 0 0 2 $1 left $2 left
56.endmacro
57
4f578862
PH
58. --- Macros for the concept and option index entries. For a "range" style of
59. --- entry, use .scindex for the start and .ecindex for the end. The first
60. --- argument of .scindex and the only argument of .ecindex must be the ID
61. --- that ties them together.
9b371988
PH
62
63.macro cindex
64&<indexterm role="concept">&
65&<primary>&$1&</primary>&
66.arg 2
67&<secondary>&$2&</secondary>&
68.endarg
69&</indexterm>&
70.endmacro
71
4f578862
PH
72.macro scindex
73&<indexterm role="concept" id="$1" class="startofrange">&
74&<primary>&$2&</primary>&
75.arg 3
76&<secondary>&$3&</secondary>&
77.endarg
78&</indexterm>&
79.endmacro
80
81.macro ecindex
82&<indexterm role="concept" startref="$1" class="endofrange"/>&
83.endmacro
84
9b371988
PH
85.macro oindex
86&<indexterm role="option">&
87&<primary>&$1&</primary>&
88.arg 2
89&<secondary>&$2&</secondary>&
90.endarg
91&</indexterm>&
92.endmacro
93
94.macro index
95.echo "** Don't use .index; use .cindex or .oindex"
96.endmacro
97. ////////////////////////////////////////////////////////////////////////////
98
99
100. ////////////////////////////////////////////////////////////////////////////
101. The <bookinfo> element is removed from the XML before processing for Ascii
102. output formats.
103. ////////////////////////////////////////////////////////////////////////////
104
105.literal xml
106<bookinfo>
107<title>Specification of the Exim Mail Transfer Agent</title>
108<titleabbrev>The Exim MTA</titleabbrev>
4f578862 109<date>22 March 2006</date>
9b371988
PH
110<author><firstname>Philip</firstname><surname>Hazel</surname></author>
111<authorinitials>PH</authorinitials>
112<affiliation><orgname>University of Cambridge Computing Service</orgname></affiliation>
113<address>New Museums Site, Pembroke Street, Cambridge CB2 3QH, England</address>
114<revhistory><revision>
4f578862
PH
115 <revnumber>4.61</revnumber>
116 <date>22 March 2006</date>
9b371988
PH
117 <authorinitials>PH</authorinitials>
118</revision></revhistory>
119<copyright><year>2006</year><holder>University of Cambridge</holder></copyright>
120</bookinfo>
121.literal off
122
123
124. /////////////////////////////////////////////////////////////////////////////
125. This chunk of literal XML implements index entries of the form "x, see y" and
126. "x, see also y". However, the DocBook DTD doesn't allow <indexterm> entries
127. at the top level, so we have to put the .chapter directive first.
128. /////////////////////////////////////////////////////////////////////////////
129
130.chapter "Introduction"
131.literal xml
132
168e428f
PH
133<indexterm role="concept">
134 <primary>$1, $2, etc.</primary>
135 <see><emphasis>numerical variables</emphasis></see>
136</indexterm>
137<indexterm role="concept">
138 <primary>address</primary>
139 <secondary>rewriting</secondary>
140 <see><emphasis>rewriting</emphasis></see>
141</indexterm>
142<indexterm role="concept">
068aaea8
PH
143 <primary>Bounce Address Tag Validation</primary>
144 <see><emphasis>BATV</emphasis></see>
145</indexterm>
146<indexterm role="concept">
147 <primary>Client SMTP Authorization</primary>
148 <see><emphasis>CSA</emphasis></see>
149</indexterm>
150<indexterm role="concept">
168e428f
PH
151 <primary>CR character</primary>
152 <see><emphasis>carriage return</emphasis></see>
153</indexterm>
154<indexterm role="concept">
155 <primary>CRL</primary>
156 <see><emphasis>certificate revocation list</emphasis></see>
157</indexterm>
158<indexterm role="concept">
159 <primary>delivery</primary>
160 <secondary>failure report</secondary>
161 <see><emphasis>bounce message</emphasis></see>
162</indexterm>
163<indexterm role="concept">
164 <primary>dialup</primary>
165 <see><emphasis>intermittently connected hosts</emphasis></see>
166</indexterm>
167<indexterm role="concept">
168 <primary>exiscan</primary>
169 <see><emphasis>content scanning</emphasis></see>
170</indexterm>
171<indexterm role="concept">
172 <primary>failover</primary>
173 <see><emphasis>fallback</emphasis></see>
174</indexterm>
175<indexterm role="concept">
176 <primary>fallover</primary>
177 <see><emphasis>fallback</emphasis></see>
178</indexterm>
179<indexterm role="concept">
180 <primary>filter</primary>
181 <secondary>Sieve</secondary>
182 <see><emphasis>Sieve filter</emphasis></see>
183</indexterm>
184<indexterm role="concept">
185 <primary>ident</primary>
186 <see><emphasis>RFC 1413</emphasis></see>
187</indexterm>
188<indexterm role="concept">
189 <primary>LF character</primary>
190 <see><emphasis>linefeed</emphasis></see>
191</indexterm>
192<indexterm role="concept">
193 <primary>maximum</primary>
194 <see><emphasis>limit</emphasis></see>
195</indexterm>
196<indexterm role="concept">
068aaea8
PH
197 <primary>monitor</primary>
198 <see><emphasis>Exim monitor</emphasis></see>
199</indexterm>
200<indexterm role="concept">
168e428f
PH
201 <primary>no_<emphasis>xxx</emphasis></primary>
202 <see>entry for xxx</see>
203</indexterm>
204<indexterm role="concept">
205 <primary>NUL</primary>
206 <see><emphasis>binary zero</emphasis></see>
207</indexterm>
208<indexterm role="concept">
209 <primary>passwd file</primary>
210 <see><emphasis>/etc/passwd</emphasis></see>
211</indexterm>
212<indexterm role="concept">
213 <primary>process id</primary>
214 <see><emphasis>pid</emphasis></see>
215</indexterm>
216<indexterm role="concept">
217 <primary>RBL</primary>
218 <see><emphasis>DNS list</emphasis></see>
219</indexterm>
220<indexterm role="concept">
221 <primary>redirection</primary>
222 <see><emphasis>address redirection</emphasis></see>
223</indexterm>
224<indexterm role="concept">
225 <primary>return path</primary>
226 <seealso><emphasis>envelope sender</emphasis></seealso>
227</indexterm>
228<indexterm role="concept">
229 <primary>scanning</primary>
230 <see><emphasis>content scanning</emphasis></see>
231</indexterm>
232<indexterm role="concept">
233 <primary>SSL</primary>
234 <see><emphasis>TLS</emphasis></see>
235</indexterm>
236<indexterm role="concept">
237 <primary>string</primary>
238 <secondary>expansion</secondary>
239 <see><emphasis>expansion</emphasis></see>
240</indexterm>
241<indexterm role="concept">
242 <primary>top bit</primary>
243 <see><emphasis>8-bit characters</emphasis></see>
244</indexterm>
245<indexterm role="concept">
246 <primary>variables</primary>
247 <see><emphasis>expansion, variables</emphasis></see>
248</indexterm>
249<indexterm role="concept">
250 <primary>zero, binary</primary>
251 <see><emphasis>binary zero</emphasis></see>
252</indexterm>
9b371988
PH
253
254.literal off
168e428f
PH
255
256
9b371988
PH
257. /////////////////////////////////////////////////////////////////////////////
258. This is the real start of the first chapter. See the comment above as to why
259. we can't have the .chapter line here.
260. chapter "Introduction"
261. /////////////////////////////////////////////////////////////////////////////
168e428f
PH
262
263Exim is a mail transfer agent (MTA) for hosts that are running Unix or
264Unix-like operating systems. It was designed on the assumption that it would be
265run on hosts that are permanently connected to the Internet. However, it can be
266used on intermittently connected hosts with suitable configuration adjustments.
267
268Configuration files currently exist for the following operating systems: AIX,
068aaea8
PH
269BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, Dragonfly, FreeBSD, GNU/Hurd,
270GNU/Linux, HI-OSF (Hitachi), HI-UX, HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD,
271OpenUNIX, QNX, SCO, SCO SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4,
272Tru64-Unix (formerly Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware.
273Some of these operating systems are no longer current and cannot easily be
274tested, so the configuration files may no longer work in practice.
168e428f
PH
275
276There are also configuration files for compiling Exim in the Cygwin environment
277that can be installed on systems running Windows. However, this document does
278not contain any information about running Exim in the Cygwin environment.
279
280The terms and conditions for the use and distribution of Exim are contained in
9b371988
PH
281the file &_NOTICE_&. Exim is distributed under the terms of the GNU General
282Public Licence, a copy of which may be found in the file &_LICENCE_&.
168e428f
PH
283
284The use, supply or promotion of Exim for the purpose of sending bulk,
285unsolicited electronic mail is incompatible with the basic aims of the program,
286which revolve around the free provision of a service that enhances the quality
287of personal communications. The author of Exim regards indiscriminate
288mass-mailing as an antisocial, irresponsible abuse of the Internet.
289
290Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
291experience of running and working on the Smail 3 code, I could never have
292contemplated starting to write a new MTA. Many of the ideas and user interfaces
293were originally taken from Smail 3, though the actual code of Exim is entirely
294new, and has developed far beyond the initial concept.
295
296Many people, both in Cambridge and around the world, have contributed to the
297development and the testing of Exim, and to porting it to various operating
298systems. I am grateful to them all. The distribution now contains a file called
9b371988 299&_ACKNOWLEDGMENTS_&, in which I have started recording the names of
168e428f
PH
300contributors.
301
302
9b371988
PH
303.section "Exim documentation"
304.new
305.cindex "documentation"
306This edition of the Exim specification applies to version &version; of Exim.
307Substantive changes from the &previousversion; edition are marked in some
168e428f
PH
308renditions of the document; this paragraph is so marked if the rendition is
309capable of showing a change indicator.
9b371988 310.wen
168e428f
PH
311
312This document is very much a reference manual; it is not a tutorial. The reader
313is expected to have some familiarity with the SMTP mail transfer protocol and
314with general Unix system administration. Although there are some discussions
315and examples in places, the information is mostly organized in a way that makes
316it easy to look up, rather than in a natural order for sequential reading.
317Furthermore, the manual aims to cover every aspect of Exim in detail, including
318a number of rarely-used, special-purpose features that are unlikely to be of
319very wide interest.
320
9b371988
PH
321.cindex "books about Exim"
322An &"easier"& discussion of Exim which provides more in-depth explanatory,
323introductory, and tutorial material can be found in a book entitled &'The Exim
324SMTP Mail Server'&, published by UIT Cambridge
325(&url(http://www.uit.co.uk/exim-book/)).
168e428f
PH
326
327This book also contains a chapter that gives a general introduction to SMTP and
328Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
329with the latest release of Exim. (Note that the earlier book about Exim,
330published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
331
9b371988 332.cindex "Debian" "information sources"
068aaea8
PH
333If you are using a Debian distribution of Exim, you will find information about
334Debian-specific features in the file
9b371988
PH
335.display
336&_/usr/share/doc/exim4-base/README.Debian_&
337.endd
338The command &(man update-exim.conf)& is another source of Debian-specific
068aaea8
PH
339information.
340
9b371988
PH
341.cindex "&_doc/NewStuff_&"
342.cindex "&_doc/ChangeLog_&"
343.cindex "change log"
168e428f
PH
344As the program develops, there may be features in newer versions that have not
345yet made it into this document, which is updated only when the most significant
346digit of the fractional part of the version number changes. Specifications of
347new features that are not yet in this manual are placed in the file
9b371988 348&_doc/NewStuff_& in the Exim distribution.
168e428f 349
9b371988 350Some features may be classified as &"experimental"&. These may change
168e428f
PH
351incompatibly while they are developing, or even be withdrawn. For this reason,
352they are not documented in this manual. Information about experimental features
9b371988 353can be found in the file &_doc/experimental.txt_&.
168e428f
PH
354
355All changes to the program (whether new features, bug fixes, or other kinds of
9b371988 356change) are noted briefly in the file called &_doc/ChangeLog_&.
168e428f 357
9b371988
PH
358.cindex "&_doc/spec.txt_&"
359This specification itself is available as an ASCII file in &_doc/spec.txt_& so
360that it can easily be searched with a text editor. Other files in the &_doc_&
168e428f
PH
361directory are:
362
9b371988
PH
363.table2 100pt
364.row &_OptionLists.txt_& "list of all options in alphabetical order"
365.row &_dbm.discuss.txt_& "discussion about DBM libraries"
366.row &_exim.8_& "a man page of Exim's command line options"
367.row &_experimental.txt_& "documentation of experimental features"
368.row &_filter.txt_& "specification of the filter language"
369.row &_pcrepattern.txt_& "specification of PCRE regular expressions"
370.row &_pcretest.txt_& "specification of the PCRE testing program"
371.row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
372.row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
373.endtable
168e428f
PH
374
375The main specification and the specification of the filtering language are also
376available in other formats (HTML, PostScript, PDF, and Texinfo). Section
9b371988 377&<<SECTavail>>& below tells you how to get hold of these.
168e428f
PH
378
379
380
9b371988
PH
381.section "FTP and web sites"
382.cindex "web site"
383.cindex "FTP site"
068aaea8 384The primary site for Exim source distributions is currently the University of
9b371988
PH
385Cambridge's FTP site, whose contents are described in &'Where to find the Exim
386distribution'& below. In addition, there is a web site and an FTP site at
387&%exim.org%&. These are now also hosted at the University of Cambridge. The
388&%exim.org%& site was previously hosted for a number of years by Energis
389Squared, formerly Planet Online Ltd, whose support I gratefully acknowledge.
390
391.cindex "wiki"
392.cindex "FAQ"
168e428f 393As well as Exim distribution tar files, the Exim web site contains a number of
9b371988
PH
394differently formatted versions of the documentation, including the FAQ in both
395text and HTML formats. The HTML version comes with a keyword-in-context index.
396A recent addition to the online information is the Exim wiki
397(&url(http://www.exim.org/eximwiki/)). We hope that this will make it easier
398for Exim users to contribute examples, tips, and know-how for the benefit of
399others.
168e428f
PH
400
401
402
9b371988
PH
403.section "Mailing lists"
404.cindex "mailing lists" "for Exim users"
168e428f
PH
405The following are the three main Exim mailing lists:
406
9b371988
PH
407.table2 140pt
408.row &'exim-users@exim.org'& "general discussion list"
409.row &'exim-dev@exim.org'& "discussion of bugs, enhancements, etc."
410.row &'exim-announce@exim.org'& "moderated, low volume announcements list"
411.endtable
168e428f
PH
412
413You can subscribe to these lists, change your existing subscriptions, and view
9b371988
PH
414or search the archives via the mailing lists link on the Exim home page.
415.cindex "Debian" "mailing list for"
4f578862
PH
416If you are using a Debian distribution of Exim, you may wish to subscribe to
417the Debian-specific mailing list &'pkg-exim4-users@lists.alioth.debian.org'&.
9b371988
PH
418
419.section "Exim training"
420.cindex "training courses"
068aaea8 421From time to time (approximately annually at the time of writing), training
9b371988
PH
422courses are run by the author of Exim in Cambridge, UK. Details of any
423forthcoming courses can be found on the web site
424&url(http://www-tus.csx.cam.ac.uk/courses/exim/).
168e428f
PH
425
426
9b371988
PH
427.section "Bug reports"
428.cindex "bug reports"
429.cindex "reporting bugs"
430Reports of obvious bugs should be emailed to &'bugs@exim.org'&. However, if you
431are unsure whether some behaviour is a bug or not, the best thing to do is to
432post a message to the &'exim-dev'& mailing list and have it discussed.
168e428f
PH
433
434
435
9b371988
PH
436.section "Where to find the Exim distribution" "SECTavail"
437.cindex "FTP site"
438.cindex "distribution" "ftp site"
168e428f 439The master ftp site for the Exim distribution is
9b371988
PH
440.display
441&*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim*&
442.endd
168e428f 443This is mirrored by
9b371988
PH
444.display
445&*ftp://ftp.exim.org/pub/exim*&
446.endd
447The file references that follow are relative to the &_exim_& directories at
448these sites. There are now quite a number of independent mirror sites around
449the world. Those that I know about are listed in the file called &_Mirrors_&.
450
451Within the &_exim_& directory there are subdirectories called &_exim3_& (for
452previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
453distributions), and &_Testing_& for testing versions. In the &_exim4_&
168e428f 454subdirectory, the current release can always be found in files called
9b371988
PH
455.display
456&_exim-n.nn.tar.gz_&
457&_exim-n.nn.tar.bz2_&
458.endd
459where &'n.nn'& is the highest such version number in the directory. The two
168e428f 460files contain identical data; the only difference is the type of compression.
9b371988 461The &_.bz2_& file is usually a lot smaller than the &_.gz_& file.
168e428f 462
9b371988
PH
463.cindex "distribution" "signing details"
464.cindex "distribution" "public key"
465.cindex "public key for signed distribution"
168e428f
PH
466The distributions are currently signed with Philip Hazel's GPG key. The
467corresponding public key is available from a number of keyservers, and there is
9b371988 468also a copy in the file &_Public-Key_&. The signatures for the tar bundles are
168e428f 469in:
9b371988
PH
470.display
471&_exim-n.nn.tar.gz.sig_&
472&_exim-n.nn.tar.bz2.sig_&
473.endd
168e428f 474For each released version, the log of changes is made separately available in a
9b371988 475separate file in the directory &_ChangeLogs_& so that it is possible to
168e428f
PH
476find out what has changed without having to download the entire distribution.
477
9b371988 478.cindex "documentation" "available formats"
168e428f
PH
479The main distribution contains ASCII versions of this specification and other
480documentation; other formats of the documents are available in separate files
9b371988
PH
481inside the &_exim4_& directory of the FTP site:
482.display
483&_exim-html-n.nn.tar.gz_&
484&_exim-pdf-n.nn.tar.gz_&
485&_exim-postscript-n.nn.tar.gz_&
486&_exim-texinfo-n.nn.tar.gz_&
487.endd
488These tar files contain only the &_doc_& directory, not the complete
489distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
490.cindex "FAQ"
168e428f 491The FAQ is available for downloading in two different formats in these files:
9b371988
PH
492.display
493&_exim4/FAQ.txt.gz_&
494&_exim4/FAQ.html.tar.gz_&
495.endd
168e428f
PH
496The first of these is a single ASCII file that can be searched with a text
497editor. The second is a directory of HTML files, normally accessed by starting
9b371988 498at &_index.html_&. The HTML version of the FAQ (which is also included in the
168e428f
PH
499HTML documentation tarbundle) includes a keyword-in-context index, which is
500often the most convenient way of finding your way around.
501
502
9b371988
PH
503.section "Wish list"
504.cindex "wish list"
168e428f
PH
505A wish list is maintained, containing ideas for new features that have been
506submitted. From time to time the file is exported to the ftp site into the file
9b371988 507&_exim4/WishList_&. Items are removed from the list if they get implemented.
168e428f
PH
508
509
510
9b371988
PH
511.section "Contributed material"
512.cindex "contributed material"
513At the ftp site, there is a directory called &_Contrib_& that contains
168e428f
PH
514miscellaneous files contributed to the Exim community by Exim users. There is
515also a collection of contributed configuration examples in
9b371988
PH
516&_exim4/config.samples.tar.gz_&. These samples are referenced from the FAQ.
517
518
519
520.section "Limitations"
521.ilist
522.cindex "limitations of Exim"
523.cindex "bang paths" "not handled by Exim"
524Exim is designed for use as an Internet MTA, and therefore handles addresses in
525RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
526simple two-component bang paths can be converted by a straightforward rewriting
527configuration. This restriction does not prevent Exim from being interfaced to
528UUCP as a transport mechanism, provided that domain addresses are used.
529.next
530.cindex "domainless addresses"
531.cindex "address" "without domain"
168e428f
PH
532Exim insists that every address it handles has a domain attached. For incoming
533local messages, domainless addresses are automatically qualified with a
534configured domain value. Configuration options specify from which remote
535systems unqualified addresses are acceptable. These are then qualified on
536arrival.
9b371988
PH
537.next
538.cindex "transport" "external"
539.cindex "external transports"
540The only external transport mechanisms that are currently implemented are SMTP
541and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
168e428f 542transport is available, and there are facilities for writing messages to files
9b371988
PH
543and pipes, optionally in &'batched SMTP'& format; these facilities can be used
544to send messages to other transport mechanisms such as UUCP, provided they can
545handle domain-style addresses. Batched SMTP input is also catered for.
546.next
547Exim is not designed for storing mail for dial-in hosts. When the volumes of
548such mail are large, it is better to get the messages &"delivered"& into files
168e428f
PH
549(that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
550other means.
9b371988
PH
551.next
552Although Exim does have basic facilities for scanning incoming messages, these
168e428f
PH
553are not comprehensive enough to do full virus or spam scanning. Such operations
554are best carried out using additional specialized software packages. If you
555compile Exim with the content-scanning extension, straightforward interfaces to
556a number of common scanners are provided.
9b371988 557.endlist
168e428f
PH
558
559
9b371988 560.section "Run time configuration"
168e428f
PH
561Exim's run time configuration is held in a single text file that is divided
562into a number of sections. The entries in this file consist of keywords and
563values, in the style of Smail 3 configuration files. A default configuration
564file which is suitable for simple online installations is provided in the
9b371988 565distribution, and is described in chapter &<<CHAPdefconfil>>& below.
168e428f
PH
566
567
9b371988
PH
568.section "Calling interface"
569.cindex "Sendmail compatibility" "command line interface"
168e428f 570Like many MTAs, Exim has adopted the Sendmail command line interface so that it
9b371988
PH
571can be a straight replacement for &_/usr/lib/sendmail_& or
572&_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
168e428f
PH
573about Sendmail in order to run Exim. For actions other than sending messages,
574Sendmail-compatible options also exist, but those that produce output (for
9b371988 575example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
168e428f 576format. There are also some additional options that are compatible with Smail
9b371988 5773, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
168e428f
PH
578documents all Exim's command line options. This information is automatically
579made into the man page that forms part of the Exim distribution.
580
581Control of messages on the queue can be done via certain privileged command
9b371988
PH
582line options. There is also an optional monitor program called &'eximon'&,
583which displays current information in an X window, and which contains a menu
168e428f
PH
584interface to Exim's command line administration options.
585
586
587
9b371988
PH
588.section "Terminology"
589.cindex "terminology definitions"
590.cindex "body of message" "definition of"
591The &'body'& of a message is the actual data that the sender wants to transmit.
592It is the last part of a message, and is separated from the &'header'& (see
168e428f
PH
593below) by a blank line.
594
9b371988 595.cindex "bounce message" "definition of"
168e428f 596When a message cannot be delivered, it is normally returned to the sender in a
9b371988
PH
597delivery failure message or a &"non-delivery report"& (NDR). The term
598&'bounce'& is commonly used for this action, and the error reports are often
599called &'bounce messages'&. This is a convenient shorthand for &"delivery
600failure error report"&. Such messages have an empty sender address in the
601message's &'envelope'& (see below) to ensure that they cannot themselves give
602rise to further bounce messages.
603
604The term &'default'& appears frequently in this manual. It is used to qualify a
168e428f
PH
605value which is used in the absence of any setting in the configuration. It may
606also qualify an action which is taken unless a configuration setting specifies
607otherwise.
608
9b371988 609The term &'defer'& is used when the delivery of a message to a specific
168e428f 610destination cannot immediately take place for some reason (a remote host may be
9b371988 611down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
168e428f
PH
612until a later time.
613
9b371988
PH
614The word &'domain'& is sometimes used to mean all but the first component of a
615host's name. It is &'not'& used in that sense here, where it normally refers to
616the part of an email address following the @ sign.
168e428f 617
9b371988
PH
618.cindex "envelope" "definition of"
619.cindex "sender" "definition of"
620A message in transit has an associated &'envelope'&, as well as a header and a
168e428f
PH
621body. The envelope contains a sender address (to which bounce messages should
622be delivered), and any number of recipient addresses. References to the
623sender or the recipients of a message usually mean the addresses in the
624envelope. An MTA uses these addresses for delivery, and for returning bounce
625messages, not the addresses that appear in the header lines.
626
9b371988
PH
627.cindex "message header" "definition of"
628.cindex "header section" "definition of"
629The &'header'& of a message is the first part of a message's text, consisting
630of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
631&'Subject:'&, etc. Long header lines can be split over several text lines by
168e428f
PH
632indenting the continuations. The header is separated from the body by a blank
633line.
634
9b371988
PH
635.cindex "local part" "definition of"
636.cindex "domain" "definition of"
637The term &'local part'&, which is taken from RFC 2822, is used to refer to that
168e428f 638part of an email address that precedes the @ sign. The part that follows the
9b371988 639@ sign is called the &'domain'& or &'mail domain'&.
168e428f 640
9b371988
PH
641.cindex "local delivery" "definition of"
642.cindex "remote delivery" "definition of"
643The terms &'local delivery'& and &'remote delivery'& are used to distinguish
168e428f 644delivery to a file or a pipe on the local host from delivery by SMTP over
068aaea8 645TCP/IP to another host. As far as Exim is concerned, all hosts other than the
9b371988 646host it is running on are &'remote'&.
168e428f 647
9b371988
PH
648.cindex "return path" "definition of"
649&'Return path'& is another name that is used for the sender address in a
168e428f
PH
650message's envelope.
651
9b371988
PH
652.cindex "queue" "definition of"
653The term &'queue'& is used to refer to the set of messages awaiting delivery,
168e428f
PH
654because this term is in widespread use in the context of MTAs. However, in
655Exim's case the reality is more like a pool than a queue, because there is
656normally no ordering of waiting messages.
657
9b371988
PH
658.cindex "queue runner" "definition of"
659The term &'queue runner'& is used to describe a process that scans the queue
168e428f 660and attempts to deliver those messages whose retry times have come. This term
9b371988 661is used by other MTAs, and also relates to the command &%runq%&, but in Exim
168e428f
PH
662the waiting messages are normally processed in an unpredictable order.
663
9b371988
PH
664.cindex "spool directory" "definition of"
665The term &'spool directory'& is used for a directory in which Exim keeps the
666messages on its queue &-- that is, those that it is in the process of
168e428f 667delivering. This should not be confused with the directory in which local
9b371988
PH
668mailboxes are stored, which is called a &"spool directory"& by some people. In
669the Exim documentation, &"spool"& is always used in the first sense.
168e428f
PH
670
671
672
673
674
675
9b371988
PH
676. ////////////////////////////////////////////////////////////////////////////
677. ////////////////////////////////////////////////////////////////////////////
168e428f 678
9b371988
PH
679.chapter "Incorporated code"
680.cindex "incorporated code"
681.cindex "regular expressions" "library"
682.cindex "PCRE"
168e428f
PH
683A number of pieces of external code are included in the Exim distribution.
684
9b371988
PH
685.ilist
686Regular expressions are supported in the main Exim program and in the Exim
687monitor using the freely-distributable PCRE library, copyright &copy;
688University of Cambridge. The source is distributed in the directory
689&_src/pcre_&. However, this is a cut-down version of PCRE. If you want to use
690the PCRE library in other programs, you should obtain and install the full
4f578862 691version from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
9b371988
PH
692.next
693.cindex "cdb" "acknowledgement"
168e428f
PH
694Support for the cdb (Constant DataBase) lookup method is provided by code
695contributed by Nigel Metheringham of (at the time he contributed it) Planet
9b371988
PH
696Online Ltd. The implementation is completely contained within the code of Exim.
697It does not link against an external cdb library. The code contains the
698following statements:
699
700.blockquote
701Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
702
168e428f
PH
703This program is free software; you can redistribute it and/or modify it under
704the terms of the GNU General Public License as published by the Free Software
705Foundation; either version 2 of the License, or (at your option) any later
706version.
9b371988 707
168e428f
PH
708This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
709the spec and sample code for cdb can be obtained from
9b371988
PH
710&url(http://www.pobox.com/~djb/cdb.html). This implementation borrows some
711code from Dan Bernstein's implementation (which has no license restrictions
712applied to it).
713.endblockquote
714.next
715.cindex "SPA authentication"
716.cindex "Samba project"
717.cindex "Microsoft Secure Password Authentication"
718Client support for Microsoft's &'Secure Password Authentication'& is provided
168e428f
PH
719by code contributed by Marc Prud'hommeaux. Server support was contributed by
720Tom Kistner. This includes code taken from the Samba project, which is released
721under the Gnu GPL.
9b371988
PH
722.next
723.cindex "Cyrus"
724.cindex "&'pwcheck'& daemon"
725.cindex "&'pwauthd'& daemon"
726Support for calling the Cyrus &'pwcheck'& and &'saslauthd'& daemons is provided
168e428f
PH
727by code taken from the Cyrus-SASL library and adapted by Alexander S.
728Sabourenkov. The permission notice appears below, in accordance with the
729conditions expressed therein.
9b371988
PH
730
731.blockquote
732Copyright &copy; 2001 Carnegie Mellon University. All rights reserved.
733
168e428f
PH
734Redistribution and use in source and binary forms, with or without
735modification, are permitted provided that the following conditions
736are met:
168e428f 737
9b371988
PH
738.olist
739Redistributions of source code must retain the above copyright
740notice, this list of conditions and the following disclaimer.
741.next
742Redistributions in binary form must reproduce the above copyright
168e428f
PH
743notice, this list of conditions and the following disclaimer in
744the documentation and/or other materials provided with the
745distribution.
9b371988
PH
746.next
747The name &"Carnegie Mellon University"& must not be used to
168e428f
PH
748endorse or promote products derived from this software without
749prior written permission. For permission or any other legal
750details, please contact
9b371988 751.display
068aaea8
PH
752 Office of Technology Transfer
753 Carnegie Mellon University
754 5000 Forbes Avenue
755 Pittsburgh, PA 15213-3890
756 (412) 268-4387, fax: (412) 268-7395
757 tech-transfer@andrew.cmu.edu
9b371988
PH
758.endd
759.next
760Redistributions of any form whatsoever must retain the following
168e428f 761acknowledgment:
9b371988
PH
762
763&"This product includes software developed by Computing Services
764at Carnegie Mellon University (&url(http://www.cmu.edu/computing/)."&
765
168e428f
PH
766CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
767THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
768AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
769FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
770WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
771AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
772OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
9b371988
PH
773.endlist
774.endblockquote
168e428f 775
9b371988
PH
776.next
777.cindex "Exim monitor" "acknowledgement"
778.cindex "X-windows"
779.cindex "Athena"
168e428f
PH
780The Exim Monitor program, which is an X-Window application, includes
781modified versions of the Athena StripChart and TextPop widgets.
782This code is copyright by DEC and MIT, and their permission notice appears
783below, in accordance with the conditions expressed therein.
9b371988
PH
784
785.blockquote
168e428f
PH
786Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
787and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
9b371988 788
168e428f 789All Rights Reserved
9b371988 790
168e428f
PH
791Permission to use, copy, modify, and distribute this software and its
792documentation for any purpose and without fee is hereby granted,
793provided that the above copyright notice appear in all copies and that
794both that copyright notice and this permission notice appear in
795supporting documentation, and that the names of Digital or MIT not be
796used in advertising or publicity pertaining to distribution of the
797software without specific, written prior permission.
9b371988 798
168e428f
PH
799DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
800ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
801DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
802ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
803WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
804ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
805SOFTWARE.
9b371988 806.endblockquote
168e428f 807
9b371988
PH
808.next
809Many people have contributed code fragments, some large, some small, that were
168e428f
PH
810not covered by any specific licence requirements. It is assumed that the
811contributors are happy to see their code incoporated into Exim under the GPL.
9b371988 812.endlist
168e428f
PH
813
814
815
816
817
9b371988
PH
818. ////////////////////////////////////////////////////////////////////////////
819. ////////////////////////////////////////////////////////////////////////////
168e428f 820
9b371988
PH
821.chapter "How Exim receives and delivers mail" "" &&&
822 "Receiving and delivering mail"
168e428f
PH
823
824
9b371988
PH
825.section "Overall philosophy"
826.cindex "design philosophy"
168e428f
PH
827Exim is designed to work efficiently on systems that are permanently connected
828to the Internet and are handling a general mix of mail. In such circumstances,
829most messages can be delivered immediately. Consequently, Exim does not
830maintain independent queues of messages for specific domains or hosts, though
831it does try to send several messages in a single SMTP connection after a host
832has been down, and it also maintains per-host retry information.
833
834
9b371988
PH
835.section "Policy control"
836.cindex "policy control" "overview"
168e428f
PH
837Policy controls are now an important feature of MTAs that are connected to the
838Internet. Perhaps their most important job is to stop MTAs being abused as
9b371988
PH
839&"open relays"& by misguided individuals who send out vast amounts of
840unsolicited junk, and want to disguise its source. Exim provides flexible
841facilities for specifying policy controls on incoming mail:
168e428f 842
9b371988
PH
843.ilist
844.cindex "&ACL;" "introduction"
168e428f 845Exim 4 (unlike previous versions of Exim) implements policy controls on
9b371988 846incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
168e428f
PH
847series of statements that may either grant or deny access. ACLs can be used at
848several places in the SMTP dialogue while receiving a message from a remote
9b371988
PH
849host. However, the most common places are after each RCPT command, and at the
850very end of the message. The sysadmin can specify conditions for accepting or
851rejecting individual recipients or the entire message, respectively, at these
852two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
168e428f 853error code.
9b371988
PH
854.next
855An ACL is also available for locally generated, non-SMTP messages. In this
168e428f 856case, the only available actions are to accept or deny the entire message.
9b371988
PH
857.next
858When Exim is compiled with the content-scanning extension, facilities are
168e428f
PH
859provided in the ACL mechanism for passing the message to external virus and/or
860spam scanning software. The result of such a scan is passed back to the ACL,
861which can then use it to decide what to do with the message.
9b371988
PH
862.next
863When a message has been received, either from a remote host or from the local
168e428f 864host, but before the final acknowledgement has been sent, a locally supplied C
9b371988
PH
865function called &[local_scan()]& can be run to inspect the message and decide
866whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
867is accepted, the list of recipients can be modified by the function.
868.next
869Using the &[local_scan()]& mechanism is another way of calling external scanner
870software. The &%SA-Exim%& add-on package works this way. It does not require
871Exim to be compiled with the content-scanning extension.
872.next
873After a message has been accepted, a further checking mechanism is available in
874the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
875runs at the start of every delivery process.
876.endlist
877
878
879
880.section "User filters"
881.cindex "filter" "introduction"
882.cindex "Sieve filter"
168e428f 883In a conventional Exim configuration, users are able to run private filters by
9b371988
PH
884setting up appropriate &_.forward_& files in their home directories. See
885chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
886configuration needed to support this, and the separate document entitled
887&'Exim's interfaces to mail filtering'& for user details. Two different kinds
888of filtering are available:
889
890.ilist
891Sieve filters are written in the standard filtering language that is defined
168e428f 892by RFC 3028.
9b371988
PH
893.next
894Exim filters are written in a syntax that is unique to Exim, but which is more
168e428f 895powerful than Sieve, which it pre-dates.
9b371988 896.endlist
168e428f
PH
897
898User filters are run as part of the routing process, described below.
899
900
901
9b371988
PH
902.section "Message identification" "SECTmessiden"
903.cindex "message ids" "details of format"
904.cindex "format" "of message id"
905.cindex "id of message"
906.cindex "base62"
907.cindex "base36"
908.cindex "Darwin"
909.cindex "Cygwin"
910Every message handled by Exim is given a &'message id'& which is sixteen
168e428f 911characters long. It is divided into three parts, separated by hyphens, for
9b371988 912example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
168e428f
PH
913normally encoding numbers in base 62. However, in the Darwin operating
914system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
915(avoiding the use of lower case letters) is used instead, because the message
916id is used to construct file names, and the names of files in those systems are
068aaea8 917not always case-sensitive.
168e428f 918
9b371988 919.cindex "pid (process id)" "re-use of"
168e428f
PH
920The detail of the contents of the message id have changed as Exim has evolved.
921Earlier versions relied on the operating system not re-using a process id (pid)
922within one second. On modern operating systems, this assumption can no longer
923be made, so the algorithm had to be changed. To retain backward compatibility,
924the format of the message id was retained, which is why the following rules are
925somewhat eccentric:
926
9b371988
PH
927.ilist
928The first six characters of the message id are the time at which the message
168e428f
PH
929started to be received, to a granularity of one second. That is, this field
930contains the number of seconds since the start of the epoch (the normal Unix
931way of representing the date and time of day).
9b371988
PH
932.next
933After the first hyphen, the next six characters are the id of the process that
168e428f 934received the message.
9b371988
PH
935.next
936There are two different possibilities for the final two characters:
937.olist
938.cindex "&%localhost_number%&"
939If &%localhost_number%& is not set, this value is the fractional part of the
168e428f
PH
940time of reception, normally in units of 1/2000 of a second, but for systems
941that must use base 36 instead of base 62 (because of case-insensitive file
942systems), the units are 1/1000 of a second.
9b371988
PH
943.next
944If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
168e428f
PH
945the fractional part of the time, which in this case is in units of 1/200
946(1/100) of a second.
9b371988
PH
947.endlist
948.endlist
168e428f
PH
949
950After a message has been received, Exim waits for the clock to tick at the
951appropriate resolution before proceeding, so that if another message is
952received by the same process, or by another process with the same (re-used)
953pid, it is guaranteed that the time will be different. In most cases, the clock
954will already have ticked while the message was being received.
955
956
9b371988
PH
957.section "Receiving mail"
958.cindex "receiving mail"
959.cindex "message" "reception"
068aaea8
PH
960The only way Exim can receive mail from another host is using SMTP over
961TCP/IP, in which case the sender and recipient addresses are transferred using
168e428f
PH
962SMTP commands. However, from a locally running process (such as a user's MUA),
963there are several possibilities:
964
9b371988
PH
965.ilist
966If the process runs Exim with the &%-bm%& option, the message is read
168e428f 967non-interactively (usually via a pipe), with the recipients taken from the
9b371988
PH
968command line, or from the body of the message if &%-t%& is also used.
969.next
970If the process runs Exim with the &%-bS%& option, the message is also read
168e428f
PH
971non-interactively, but in this case the recipients are listed at the start of
972the message in a series of SMTP RCPT commands, terminated by a DATA
9b371988 973command. This is so-called &"batch SMTP"& format,
168e428f
PH
974but it isn't really SMTP. The SMTP commands are just another way of passing
975envelope addresses in a non-interactive submission.
9b371988
PH
976.next
977If the process runs Exim with the &%-bs%& option, the message is read
168e428f
PH
978interactively, using the SMTP protocol. A two-way pipe is normally used for
979passing data between the local process and the Exim process.
9b371988 980This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
168e428f 981example, the ACLs for SMTP commands are used for this form of submission.
9b371988
PH
982.next
983A local process may also make a TCP/IP call to the host's loopback address
168e428f
PH
984(127.0.0.1) or any other of its IP addresses. When receiving messages, Exim
985does not treat the loopback address specially. It treats all such connections
986in the same way as connections from other hosts.
9b371988 987.endlist
168e428f
PH
988
989
9b371988
PH
990.cindex "message sender" "constructed by Exim"
991.cindex "sender" "constructed by Exim"
168e428f
PH
992In the three cases that do not involve TCP/IP, the sender address is
993constructed from the login name of the user that called Exim and a default
9b371988 994qualification domain (which can be set by the &%qualify_domain%& configuration
168e428f
PH
995option). For local or batch SMTP, a sender address that is passed using the
996SMTP MAIL command is ignored. However, the system administrator may allow
9b371988 997certain users (&"trusted users"&) to specify a different sender address
168e428f 998unconditionally, or all users to specify certain forms of different sender
9b371988
PH
999address. The &%-f%& option or the SMTP MAIL command is used to specify these
1000different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1001users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
168e428f
PH
1002users to change sender addresses.
1003
1004Messages received by either of the non-interactive mechanisms are subject to
1005checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1006(either over TCP/IP, or interacting with a local process) can be checked by a
1007number of ACLs that operate at different times during the SMTP session. Either
1008individual recipients, or the entire message, can be rejected if local policy
9b371988
PH
1009requirements are not met. The &[local_scan()]& function (see chapter
1010&<<CHAPlocalscan>>&) is run for all incoming messages.
168e428f
PH
1011
1012Exim can be configured not to start a delivery process when a message is
1013received; this can be unconditional, or depend on the number of incoming SMTP
1014connections or the system load. In these situations, new messages wait on the
1015queue until a queue runner process picks them up. However, in standard
1016configurations under normal conditions, delivery is started as soon as a
1017message is received.
1018
1019
1020
1021
1022
9b371988
PH
1023.section "Handling an incoming message"
1024.cindex "spool directory" "files that hold a message"
1025.cindex "file" "how a message is held"
168e428f
PH
1026When Exim accepts a message, it writes two files in its spool directory. The
1027first contains the envelope information, the current status of the message, and
1028the header lines, and the second contains the body of the message. The names of
9b371988
PH
1029the two spool files consist of the message id, followed by &`-H`& for the
1030file containing the envelope and header, and &`-D`& for the data file.
168e428f 1031
9b371988 1032.cindex "spool directory" "&_input_& sub-directory"
168e428f 1033By default all these message files are held in a single directory called
9b371988 1034&_input_& inside the general Exim spool directory. Some operating systems do
168e428f 1035not perform very well if the number of files in a directory gets very large; to
9b371988 1036improve performance in such cases, the &%split_spool_directory%& option can be
168e428f
PH
1037used. This causes Exim to split up the input files into 62 sub-directories
1038whose names are single letters or digits.
1039
1040The envelope information consists of the address of the message's sender and
1041the addresses of the recipients. This information is entirely separate from
1042any addresses contained in the header lines. The status of the message includes
1043a list of recipients who have already received the message. The format of the
9b371988 1044first spool file is described in chapter &<<CHAPspool>>&.
168e428f 1045
9b371988 1046.cindex "rewriting" "addresses"
168e428f 1047Address rewriting that is specified in the rewrite section of the configuration
9b371988 1048(see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
168e428f
PH
1049both in the header lines and the envelope, at the time the message is accepted.
1050If during the course of delivery additional addresses are generated (for
1051example, via aliasing), these new addresses are rewritten as soon as they are
1052generated. At the time a message is actually delivered (transported) further
1053rewriting can take place; because this is a transport option, it can be
1054different for different forms of delivery. It is also possible to specify the
1055addition or removal of certain header lines at the time the message is
9b371988
PH
1056delivered (see chapters &<<CHAProutergeneric>>& and
1057&<<CHAPtransportgeneric>>&).
168e428f
PH
1058
1059
1060
9b371988
PH
1061.section "Life of a message"
1062.cindex "message" "life of"
1063.cindex "message" "frozen"
168e428f
PH
1064A message remains in the spool directory until it is completely delivered to
1065its recipients or to an error address, or until it is deleted by an
1066administrator or by the user who originally created it. In cases when delivery
9b371988
PH
1067cannot proceed &-- for example, when a message can neither be delivered to its
1068recipients nor returned to its sender, the message is marked &"frozen"& on the
168e428f
PH
1069spool, and no more deliveries are attempted.
1070
9b371988
PH
1071.cindex "frozen messages" "thawing"
1072.cindex "message" "thawing frozen"
1073An administrator can &"thaw"& such messages when the problem has been
1074corrected, and can also freeze individual messages by hand if necessary. In
1075addition, an administrator can force a delivery error, causing a bounce message
1076to be sent.
1077
9b371988
PH
1078.cindex "&%timeout_frozen_after%&"
1079.cindex "&%ignore_bounce_errors_after%&"
1080There are options called &%ignore_bounce_errors_after%& and
1081&%timeout_frozen_after%&, which discard frozen messages after a certain time.
068aaea8 1082The first applies only to frozen bounces, the second to any frozen messages.
168e428f 1083
9b371988
PH
1084.cindex "message" "log file for"
1085.cindex "log" "file for each message"
168e428f 1086While Exim is working on a message, it writes information about each delivery
068aaea8 1087attempt to its main log file. This includes successful, unsuccessful, and
9b371988
PH
1088delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1089lines are also written to a separate &'message log'& file for each message.
1090These logs are solely for the benefit of the administrator, and are normally
1091deleted along with the spool files when processing of a message is complete.
168e428f 1092The use of individual message logs can be disabled by setting
9b371988
PH
1093&%no_message_logs%&; this might give an improvement in performance on very busy
1094systems.
168e428f 1095
9b371988
PH
1096.cindex "journal file"
1097.cindex "file" "journal"
168e428f
PH
1098All the information Exim itself needs to set up a delivery is kept in the first
1099spool file, along with the header lines. When a successful delivery occurs, the
1100address is immediately written at the end of a journal file, whose name is the
9b371988
PH
1101message id followed by &`-J`&. At the end of a delivery run, if there are some
1102addresses left to be tried again later, the first spool file (the &`-H`& file)
168e428f
PH
1103is updated to indicate which these are, and the journal file is then deleted.
1104Updating the spool file is done by writing a new file and renaming it, to
1105minimize the possibility of data loss.
1106
1107Should the system or the program crash after a successful delivery but before
1108the spool file has been updated, the journal is left lying around. The next
1109time Exim attempts to deliver the message, it reads the journal file and
1110updates the spool file before proceeding. This minimizes the chances of double
1111deliveries caused by crashes.
1112
1113
1114
9b371988
PH
1115.section "Processing an address for delivery" "SECTprocaddress"
1116.cindex "drivers" "definition of"
1117.cindex "router" "definition of"
1118.cindex "transport" "definition of"
1119The main delivery processing elements of Exim are called &'routers'& and
1120&'transports'&, and collectively these are known as &'drivers'&. Code for a
168e428f
PH
1121number of them is provided in the source distribution, and compile-time options
1122specify which ones are included in the binary. Run time options specify which
1123ones are actually used for delivering messages.
1124
9b371988
PH
1125.cindex "drivers" "instance definition"
1126Each driver that is specified in the run time configuration is an &'instance'&
168e428f 1127of that particular driver type. Multiple instances are allowed; for example,
9b371988 1128you can set up several different &(smtp)& transports, each with different
168e428f
PH
1129option values that might specify different ports or different timeouts. Each
1130instance has its own identifying name. In what follows we will normally use the
1131instance name when discussing one particular instance (that is, one specific
1132configuration of the driver), and the generic driver name when discussing
1133the driver's features in general.
1134
9b371988 1135A &'router'& is a driver that operates on an address, either determining how
068aaea8 1136its delivery should happen, by assigning it to a specific transport, or
168e428f
PH
1137converting the address into one or more new addresses (for example, via an
1138alias file). A router may also explicitly choose to fail an address, causing it
1139to be bounced.
1140
9b371988
PH
1141A &'transport'& is a driver that transmits a copy of the message from Exim's
1142spool to some destination. There are two kinds of transport: for a &'local'&
168e428f 1143transport, the destination is a file or a pipe on the local host, whereas for a
9b371988 1144&'remote'& transport the destination is some other host. A message is passed
168e428f
PH
1145to a specific transport as a result of successful routing. If a message has
1146several recipients, it may be passed to a number of different transports.
1147
9b371988 1148.cindex "preconditions" "definition of"
168e428f
PH
1149An address is processed by passing it to each configured router instance in
1150turn, subject to certain preconditions, until a router accepts the address or
1151specifies that it should be bounced. We will describe this process in more
068aaea8
PH
1152detail shortly. First, as a simple example, we consider how each recipient
1153address in a message is processed in a small configuration of three routers.
168e428f 1154
068aaea8 1155To make this a more concrete example, it is described in terms of some actual
168e428f
PH
1156routers, but remember, this is only an example. You can configure Exim's
1157routers in many different ways, and there may be any number of routers in a
1158configuration.
1159
1160The first router that is specified in a configuration is often one that handles
1161addresses in domains that are not recognized specially by the local host. These
1162are typically addresses for arbitrary domains on the Internet. A precondition
1163is set up which looks for the special domains known to the host (for example,
9b371988 1164its own domain name), and the router is run for addresses that do &'not'&
168e428f
PH
1165match. Typically, this is a router that looks up domains in the DNS in order to
1166find the hosts to which this address routes. If it succeeds, the address is
068aaea8 1167assigned to a suitable SMTP transport; if it does not succeed, the router is
168e428f
PH
1168configured to fail the address.
1169
068aaea8 1170The second router is reached only when the domain is recognized as one that
9b371988 1171&"belongs"& to the local host. This router does redirection &-- also known as
068aaea8
PH
1172aliasing and forwarding. When it generates one or more new addresses from the
1173original, each of them is routed independently from the start. Otherwise, the
1174router may cause an address to fail, or it may simply decline to handle the
1175address, in which case the address is passed to the next router.
168e428f
PH
1176
1177The final router in many configurations is one that checks to see if the
1178address belongs to a local mailbox. The precondition may involve a check to
1179see if the local part is the name of a login account, or it may look up the
1180local part in a file or a database. If its preconditions are not met, or if
1181the router declines, we have reached the end of the routers. When this happens,
1182the address is bounced.
1183
1184
1185
9b371988
PH
1186.section "Processing an address for verification"
1187.cindex "router" "for verification"
1188.cindex "verifying address" "overview"
168e428f 1189As well as being used to decide how to deliver to an address, Exim's routers
9b371988 1190are also used for &'address verification'&. Verification can be requested as
168e428f 1191one of the checks to be performed in an ACL for incoming messages, on both
9b371988
PH
1192sender and recipient addresses, and it can be tested using the &%-bv%& and
1193&%-bvs%& command line options.
168e428f 1194
9b371988 1195When an address is being verified, the routers are run in &"verify mode"&. This
168e428f
PH
1196does not affect the way the routers work, but it is a state that can be
1197detected. By this means, a router can be skipped or made to behave differently
1198when verifying. A common example is a configuration in which the first router
1199sends all messages to a message-scanning program, unless they have been
1200previously scanned. Thus, the first router accepts all addresses without any
9b371988 1201checking, making it useless for verifying. Normally, the &%no_verify%& option
168e428f
PH
1202would be set for such a router, causing it to be skipped in verify mode.
1203
1204
1205
1206
9b371988
PH
1207.section "Running an individual router" "SECTrunindrou"
1208.cindex "router" "running details"
1209.cindex "preconditions" "checking"
1210.cindex "router" "result of running"
168e428f
PH
1211As explained in the example above, a number of preconditions are checked before
1212running a router. If any are not met, the router is skipped, and the address is
9b371988 1213passed to the next router. When all the preconditions on a router &'are'& met,
168e428f
PH
1214the router is run. What happens next depends on the outcome, which is one of
1215the following:
1216
9b371988
PH
1217.ilist
1218&'accept'&: The router accepts the address, and either assigns it to a
1219transport, or generates one or more &"child"& addresses. Processing the
1220original address ceases,
1221.cindex "&%unseen%& option"
1222unless the &%unseen%& option is set on the router. This option
168e428f 1223can be used to set up multiple deliveries with different routing (for example,
9b371988
PH
1224for keeping archive copies of messages). When &%unseen%& is set, the address is
1225passed to the next router. Normally, however, an &'accept'& return marks the
168e428f 1226end of routing.
9b371988 1227
068aaea8
PH
1228Any child addresses generated by the router are processed independently,
1229starting with the first router by default. It is possible to change this by
9b371988
PH
1230setting the &%redirect_router%& option to specify which router to start at for
1231child addresses. Unlike &%pass_router%& (see below) the router specified by
1232&%redirect_router%& may be anywhere in the router configuration.
1233.next
1234&'pass'&: The router recognizes the address, but cannot handle it itself. It
168e428f
PH
1235requests that the address be passed to another router. By default the address
1236is passed to the next router, but this can be changed by setting the
9b371988 1237&%pass_router%& option. However, (unlike &%redirect_router%&) the named router
168e428f 1238must be below the current router (to avoid loops).
9b371988
PH
1239.next
1240&'decline'&: The router declines to accept the address because it does not
168e428f 1241recognize it at all. By default, the address is passed to the next router, but
9b371988
PH
1242this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1243set, all the remaining routers are skipped. In effect, &%no_more%& converts
1244&'decline'& into &'fail'&.
1245.next
1246&'fail'&: The router determines that the address should fail, and queues it for
168e428f 1247the generation of a bounce message. There is no further processing of the
9b371988
PH
1248original address unless &%unseen%& is set on the router.
1249.next
1250&'defer'&: The router cannot handle the address at the present time. (A
068aaea8
PH
1251database may be offline, or a DNS lookup may have timed out.) No further
1252processing of the address happens in this delivery attempt. It is tried again
1253next time the message is considered for delivery.
9b371988
PH
1254.next
1255&'error'&: There is some error in the router (for example, a syntax error in
168e428f 1256its configuration). The action is as for defer.
9b371988 1257.endlist
168e428f
PH
1258
1259If an address reaches the end of the routers without having been accepted by
068aaea8 1260any of them, it is bounced as unrouteable. The default error message in this
9b371988
PH
1261situation is &"unrouteable address"&, but you can set your own message by
1262making use of the &%cannot_route_message%& option. This can be set for any
1263router; the value from the last router that &"saw"& the address is used.
168e428f
PH
1264
1265Sometimes while routing you want to fail a delivery when some conditions are
1266met but others are not, instead of passing the address on for further routing.
1267You can do this by having a second router that explicitly fails the delivery
9b371988 1268when the relevant conditions are met. The &(redirect)& router has a &"fail"&
168e428f
PH
1269facility for this purpose.
1270
1271
9b371988 1272.section "Duplicate addresses"
9b371988
PH
1273.cindex "case of local parts"
1274.cindex "address duplicate" "discarding"
068aaea8
PH
1275Once routing is complete, Exim scans the addresses that are assigned to local
1276and remote transports, and discards any duplicates that it finds. During this
1277check, local parts are treated as case-sensitive.
1278
168e428f 1279
9b371988
PH
1280.section "Router preconditions" "SECTrouprecon"
1281.cindex "router preconditions" "order of processing"
1282.cindex "preconditions" "order of processing"
168e428f
PH
1283The preconditions that are tested for each router are listed below, in the
1284order in which they are tested. The individual configuration options are
9b371988 1285described in more detail in chapter &<<CHAProutergeneric>>&.
168e428f 1286
9b371988
PH
1287.ilist
1288The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
168e428f
PH
1289the local parts handled by the router may or must have certain prefixes and/or
1290suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1291skipped. These conditions are tested first. When an affix is present, it is
1292removed from the local part before further processing, including the evaluation
1293of any other conditions.
9b371988
PH
1294.next
1295Routers can be designated for use only when not verifying an address, that is,
168e428f 1296only when routing it for delivery (or testing its delivery routing). If the
9b371988 1297&%verify%& option is set false, the router is skipped when Exim is verifying an
168e428f 1298address.
9b371988
PH
1299Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1300&%verify_recipient%&, which independently control the use of the router for
168e428f
PH
1301sender and recipient verification. You can set these options directly if
1302you want a router to be used for only one type of verification.
9b371988
PH
1303.next
1304If the &%address_test%& option is set false, the router is skipped when Exim is
1305run with the &%-bt%& option to test an address routing. This can be helpful
1306when the first router sends all new messages to a scanner of some sort; it
1307makes it possible to use &%-bt%& to test subsequent delivery routing without
1308having to simulate the effect of the scanner.
1309.next
1310Routers can be designated for use only when verifying an address, as
1311opposed to routing it for delivery. The &%verify_only%& option controls this.
1312.next
1313Individual routers can be explicitly skipped when running the routers to
1314check an address given in the SMTP EXPN command (see the &%expn%& option).
1315.next
1316If the &%domains%& option is set, the domain of the address must be in the set
068aaea8 1317of domains that it defines.
9b371988
PH
1318.next
1319.cindex "&$local_part_prefix$&"
1320.cindex "&$local_part$&"
1321.cindex "&$local_part_suffix$&"
1322If the &%local_parts%& option is set, the local part of the address must be in
1323the set of local parts that it defines. If &%local_part_prefix%& or
1324&%local_part_suffix%& is in use, the prefix or suffix is removed from the local
168e428f 1325part before this check. If you want to do precondition tests on local parts
9b371988
PH
1326that include affixes, you can do so by using a &%condition%& option (see below)
1327that uses the variables &$local_part$&, &$local_part_prefix$&, and
1328&$local_part_suffix$& as necessary.
1329.next
1330.cindex "&$local_user_uid$&"
1331.cindex "&$local_user_gid$&"
1332.cindex "&$home$&"
1333If the &%check_local_user%& option is set, the local part must be the name of
068aaea8 1334an account on the local host. If this check succeeds, the uid and gid of the
9b371988
PH
1335local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1336user's home directory is placed in &$home$&; these values can be used in the
1337remaining preconditions.
1338.next
1339If the &%router_home_directory%& option is set, it is expanded at this point,
1340because it overrides the value of &$home$&. If this expansion were left till
1341later, the value of &$home$& as set by &%check_local_user%& would be used in
1342subsequent tests. Having two different values of &$home$& in the same router
168e428f 1343could lead to confusion.
9b371988
PH
1344.next
1345If the &%senders%& option is set, the envelope sender address must be in the
1346set of addresses that it defines.
1347.next
1348If the &%require_files%& option is set, the existence or non-existence of
168e428f 1349specified files is tested.
9b371988
PH
1350.next
1351.cindex "customizing" "precondition"
1352If the &%condition%& option is set, it is evaluated and tested. This option
1353uses an expanded string to allow you to set up your own custom preconditions.
1354Expanded strings are described in chapter &<<CHAPexpand>>&.
1355.endlist
168e428f 1356
168e428f 1357
9b371988
PH
1358Note that &%require_files%& comes near the end of the list, so you cannot use
1359it to check for the existence of a file in which to lookup up a domain, local
168e428f 1360part, or sender. However, as these options are all expanded, you can use the
9b371988
PH
1361&%exists%& expansion condition to make such tests within each condition. The
1362&%require_files%& option is intended for checking files that the router may be
168e428f 1363going to use internally, or which are needed by a specific transport (for
9b371988 1364example, &_.procmailrc_&).
168e428f
PH
1365
1366
1367
9b371988
PH
1368.section "Delivery in detail"
1369.cindex "delivery" "in detail"
168e428f
PH
1370When a message is to be delivered, the sequence of events is as follows:
1371
9b371988
PH
1372.ilist
1373If a system-wide filter file is specified, the message is passed to it. The
168e428f
PH
1374filter may add recipients to the message, replace the recipients, discard the
1375message, cause a new message to be generated, or cause the message delivery to
1376fail. The format of the system filter file is the same as for Exim user filter
9b371988
PH
1377files, described in the separate document entitled &'Exim's interfaces to mail
1378filtering'&.
1379.cindex "Sieve filter" "not available for system filter"
1380(&*Note*&: Sieve cannot be used for system filter files.)
1381
1382Some additional features are available in system filters &-- see chapter
1383&<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
168e428f
PH
1384filter only once per delivery attempt, however many recipients it has. However,
1385if there are several delivery attempts because one or more addresses could not
1386be immediately delivered, the system filter is run each time. The filter
9b371988 1387condition &%first_delivery%& can be used to detect the first run of the system
168e428f 1388filter.
9b371988
PH
1389.next
1390Each recipient address is offered to each configured router in turn, subject to
1391its preconditions, until one is able to handle it. If no router can handle the
1392address, that is, if they all decline, the address is failed. Because routers
1393can be targeted at particular domains, several locally handled domains can be
1394processed entirely independently of each other.
1395.next
1396.cindex "routing" "loops in"
1397.cindex "loop" "while routing"
1398A router that accepts an address may assign it to a local or a remote
1399transport. However, the transport is not run at this time. Instead, the address
1400is placed on a list for the particular transport, which will be run later.
068aaea8
PH
1401Alternatively, the router may generate one or more new addresses (typically
1402from alias, forward, or filter files). New addresses are fed back into this
1403process from the top, but in order to avoid loops, a router ignores any address
1404which has an identically-named ancestor that was processed by itself.
9b371988
PH
1405.next
1406When all the routing has been done, addresses that have been successfully
168e428f
PH
1407handled are passed to their assigned transports. When local transports are
1408doing real local deliveries, they handle only one address at a time, but if a
1409local transport is being used as a pseudo-remote transport (for example, to
1410collect batched SMTP messages for transmission by some other means) multiple
1411addresses can be handled. Remote transports can always handle more than one
1412address at a time, but can be configured not to do so, or to restrict multiple
1413addresses to the same domain.
9b371988
PH
1414.next
1415Each local delivery to a file or a pipe runs in a separate process under a
168e428f
PH
1416non-privileged uid, and these deliveries are run one at a time. Remote
1417deliveries also run in separate processes, normally under a uid that is private
9b371988 1418to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
168e428f 1419run in parallel. The maximum number of simultaneous remote deliveries for any
9b371988 1420one message is set by the &%remote_max_parallel%& option.
168e428f
PH
1421The order in which deliveries are done is not defined, except that all local
1422deliveries happen before any remote deliveries.
9b371988
PH
1423.next
1424.cindex "queue runner"
168e428f
PH
1425When it encounters a local delivery during a queue run, Exim checks its retry
1426database to see if there has been a previous temporary delivery failure for the
1427address before running the local transport. If there was a previous failure,
1428Exim does not attempt a new delivery until the retry time for the address is
1429reached. However, this happens only for delivery attempts that are part of a
1430queue run. Local deliveries are always attempted when delivery immediately
1431follows message reception, even if retry times are set for them. This makes for
1432better behaviour if one particular message is causing problems (for example,
1433causing quota overflow, or provoking an error in a filter file).
9b371988
PH
1434.next
1435.cindex "delivery" "retry in remote transports"
168e428f
PH
1436Remote transports do their own retry handling, since an address may be
1437deliverable to one of a number of hosts, each of which may have a different
1438retry time. If there have been previous temporary failures and no host has
1439reached its retry time, no delivery is attempted, whether in a queue run or
9b371988
PH
1440not. See chapter &<<CHAPretry>>& for details of retry strategies.
1441.next
1442If there were any permanent errors, a bounce message is returned to an
168e428f
PH
1443appropriate address (the sender in the common case), with details of the error
1444for each failing address. Exim can be configured to send copies of bounce
1445messages to other addresses.
9b371988
PH
1446.next
1447.cindex "delivery" "deferral"
168e428f
PH
1448If one or more addresses suffered a temporary failure, the message is left on
1449the queue, to be tried again later. Delivery of these addresses is said to be
9b371988
PH
1450&'deferred'&.
1451.next
1452When all the recipient addresses have either been delivered or bounced,
168e428f
PH
1453handling of the message is complete. The spool files and message log are
1454deleted, though the message log can optionally be preserved if required.
9b371988 1455.endlist
168e428f
PH
1456
1457
1458
1459
9b371988
PH
1460.section "Retry mechanism"
1461.cindex "delivery" "retry mechanism"
1462.cindex "retry" "description of mechanism"
1463.cindex "queue runner"
168e428f
PH
1464Exim's mechanism for retrying messages that fail to get delivered at the first
1465attempt is the queue runner process. You must either run an Exim daemon that
9b371988
PH
1466uses the &%-q%& option with a time interval to start queue runners at regular
1467intervals, or use some other means (such as &'cron'&) to start them. If you do
168e428f
PH
1468not arrange for queue runners to be run, messages that fail temporarily at the
1469first attempt will remain on your queue for ever. A queue runner process works
068aaea8 1470its way through the queue, one message at a time, trying each delivery that has
168e428f
PH
1471passed its retry time.
1472You can run several queue runners at once.
1473
1474Exim uses a set of configured rules to determine when next to retry the failing
9b371988
PH
1475address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1476should give up trying to deliver to the address, at which point it generates a
1477bounce message. If no retry rules are set for a particular host, address, and
1478error combination, no retries are attempted, and temporary errors are treated
1479as permanent.
168e428f
PH
1480
1481
1482
9b371988
PH
1483.section "Temporary delivery failure"
1484.cindex "delivery" "temporary failure"
168e428f
PH
1485There are many reasons why a message may not be immediately deliverable to a
1486particular address. Failure to connect to a remote machine (because it, or the
1487connection to it, is down) is one of the most common. Temporary failures may be
1488detected during routing as well as during the transport stage of delivery.
1489Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1490is on a file system where the user is over quota. Exim can be configured to
1491impose its own quotas on local mailboxes; where system quotas are set they will
1492also apply.
1493
1494If a host is unreachable for a period of time, a number of messages may be
1495waiting for it by the time it recovers, and sending them in a single SMTP
1496connection is clearly beneficial. Whenever a delivery to a remote host is
1497deferred,
1498
9b371988 1499.cindex "hints database"
168e428f
PH
1500Exim makes a note in its hints database, and whenever a successful
1501SMTP delivery has happened, it looks to see if any other messages are waiting
1502for the same host. If any are found, they are sent over the same SMTP
1503connection, subject to a configuration limit as to the maximum number in any
1504one connection.
1505
1506
1507
1508
9b371988
PH
1509.section "Permanent delivery failure"
1510.cindex "delivery" "permanent failure"
1511.cindex "bounce message" "when generated"
168e428f
PH
1512When a message cannot be delivered to some or all of its intended recipients, a
1513bounce message is generated. Temporary delivery failures turn into permanent
1514errors when their timeout expires. All the addresses that fail in a given
1515delivery attempt are listed in a single message. If the original message has
1516many recipients, it is possible for some addresses to fail in one delivery
1517attempt and others to fail subsequently, giving rise to more than one bounce
1518message. The wording of bounce messages can be customized by the administrator.
9b371988 1519See chapter &<<CHAPemsgcust>>& for details.
168e428f 1520
9b371988
PH
1521.cindex "&'X-Failed-Recipients:'& header line"
1522Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
168e428f
PH
1523failed addresses, for the benefit of programs that try to analyse such messages
1524automatically.
1525
9b371988 1526.cindex "bounce message" "recipient of"
168e428f
PH
1527A bounce message is normally sent to the sender of the original message, as
1528obtained from the message's envelope. For incoming SMTP messages, this is the
9b371988
PH
1529address given in the MAIL command. However, when an address is expanded via a
1530forward or alias file, an alternative address can be specified for delivery
1531failures of the generated addresses. For a mailing list expansion (see section
1532&<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1533of the list.
168e428f
PH
1534
1535
1536
9b371988
PH
1537.section "Failures to deliver bounce messages"
1538.cindex "bounce message" "failure to deliver"
168e428f
PH
1539If a bounce message (either locally generated or received from a remote host)
1540itself suffers a permanent delivery failure, the message is left on the queue,
1541but it is frozen, awaiting the attention of an administrator. There are options
068aaea8 1542that can be used to make Exim discard such failed messages, or to keep them
9b371988
PH
1543for only a short time (see &%timeout_frozen_after%& and
1544&%ignore_bounce_errors_after%&).
168e428f
PH
1545
1546
1547
1548
1549
9b371988
PH
1550. ////////////////////////////////////////////////////////////////////////////
1551. ////////////////////////////////////////////////////////////////////////////
168e428f 1552
9b371988 1553.chapter "Building and installing Exim"
4f578862 1554.scindex IIDbuex "building Exim"
168e428f 1555
9b371988 1556.section "Unpacking"
168e428f
PH
1557Exim is distributed as a gzipped or bzipped tar file which, when upacked,
1558creates a directory with the name of the current release (for example,
9b371988
PH
1559&_exim-&version;_&) into which the following files are placed:
1560
1561.table2 140pt
1562.row &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1563.row &_CHANGES_& "contains a reference to where changes are documented"
1564.row &_LICENCE_& "the GNU General Public Licence"
1565.row &_Makefile_& "top-level make file"
1566.row &_NOTICE_& "conditions for the use of Exim"
1567.row &_README_& "list of files, directories and simple build &&&
1568 instructions"
1569.endtable
1570
1571Other files whose names begin with &_README_& may also be present. The
168e428f
PH
1572following subdirectories are created:
1573
9b371988
PH
1574.table2 140pt
1575.row &_Local_& "an empty directory for local configuration files"
1576.row &_OS_& "OS-specific files"
1577.row &_doc_& "documentation files"
1578.row &_exim_monitor_& "source files for the Exim monitor"
1579.row &_scripts_& "scripts used in the build process"
1580.row &_src_& "remaining source files"
1581.row &_util_& "independent utilities"
1582.endtable
1583
1584The main utility programs are contained in the &_src_& directory, and are built
1585with the Exim binary. The &_util_& directory contains a few optional scripts
168e428f
PH
1586that may be useful to some sites.
1587
1588
9b371988
PH
1589.section "Multiple machine architectures and operating systems"
1590.cindex "building Exim" "multiple OS/architectures"
168e428f
PH
1591The building process for Exim is arranged to make it easy to build binaries for
1592a number of different architectures and operating systems from the same set of
9b371988
PH
1593source files. Compilation does not take place in the &_src_& directory.
1594Instead, a &'build directory'& is created for each architecture and operating
1595system.
1596.cindex "symbolic link" "to build directory"
168e428f 1597Symbolic links to the sources are installed in this directory, which is where
9b371988
PH
1598the actual building takes place. In most cases, Exim can discover the machine
1599architecture and operating system for itself, but the defaults can be
1600overridden if necessary.
168e428f 1601
168e428f 1602
9b371988
PH
1603.section "DBM libraries" "SECTdb"
1604.cindex "DBM libraries" "discussion of"
1605.cindex "hints database" "DBM files used for"
168e428f
PH
1606Even if you do not use any DBM files in your configuration, Exim still needs a
1607DBM library in order to operate, because it uses indexed files for its hints
1608databases. Unfortunately, there are a number of DBM libraries in existence, and
1609different operating systems often have different ones installed.
1610
9b371988
PH
1611.cindex "Solaris" "DBM library for"
1612.cindex "IRIX" "DBM library for"
1613.cindex "BSD" "DBM library for"
1614.cindex "Linux" "DBM library for"
168e428f
PH
1615If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1616Linux distribution, the DBM configuration should happen automatically, and you
1617may be able to ignore this section. Otherwise, you may have to learn more than
1618you would like about DBM libraries from what follows.
1619
9b371988 1620.cindex "&'ndbm'& DBM library"
168e428f 1621Licensed versions of Unix normally contain a library of DBM functions operating
9b371988 1622via the &'ndbm'& interface, and this is what Exim expects by default. Free
168e428f
PH
1623versions of Unix seem to vary in what they contain as standard. In particular,
1624some early versions of Linux have no default DBM library, and different
1625distributors have chosen to bundle different libraries with their packaged
1626versions. However, the more recent releases seem to have standardised on the
1627Berkeley DB library.
1628
1629Different DBM libraries have different conventions for naming the files they
9b371988 1630use. When a program opens a file called &_dbmfile_&, there are several
168e428f
PH
1631possibilities:
1632
9b371988
PH
1633.olist
1634A traditional &'ndbm'& implementation, such as that supplied as part of
1635Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1636.next
1637.cindex "&'gdbm'& DBM library"
1638The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
168e428f 1639compatibility interface it makes two different hard links to it with names
9b371988 1640&_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
168e428f 1641file name is used unmodified.
9b371988
PH
1642.next
1643.cindex "Berkeley DB library"
1644The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1645operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1646programmer exactly the same as the traditional &'ndbm'& implementation.
1647.next
1648If the Berkeley package is used in its native mode, it operates on a single
1649file called &_dbmfile_&; the programmer's interface is somewhat different to
1650the traditional &'ndbm'& interface.
1651.next
1652To complicate things further, there are several very different versions of the
168e428f 1653Berkeley DB package. Version 1.85 was stable for a very long time, releases
9b371988
PH
16542.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1655numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
168e428f 1656versions of Berkeley DB can be obtained from
9b371988
PH
1657&url(http://www.sleepycat.com/).
1658.next
1659.cindex "&'tdb'& DBM library"
1660Yet another DBM library, called &'tdb'&, is available from
1661&url(http://download.sourceforge.net/tdb). It has its own interface, and also
1662operates on a single file.
1663.endlist
1664
1665.cindex "USE_DB"
1666.cindex "DBM libraries" "configuration for building"
168e428f
PH
1667Exim and its utilities can be compiled to use any of these interfaces. In order
1668to use any version of the Berkeley DB package in native mode, you must set
1669USE_DB in an appropriate configuration file (typically
9b371988
PH
1670&_Local/Makefile_&). For example:
1671.code
1672USE_DB=yes
1673.endd
168e428f
PH
1674Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1675error is diagnosed if you set more than one of these.
1676
1677At the lowest level, the build-time configuration sets none of these options,
1678thereby assuming an interface of type (1). However, some operating system
1679configuration files (for example, those for the BSD operating systems and
1680Linux) assume type (4) by setting USE_DB as their default, and the
1681configuration files for Cygwin set USE_GDBM. Anything you set in
9b371988 1682&_Local/Makefile_&, however, overrides these system defaults.
168e428f
PH
1683
1684As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1685necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1686in one of these lines:
9b371988
PH
1687.code
1688DBMLIB = -ldb
1689DBMLIB = -ltdb
1690.endd
168e428f
PH
1691Settings like that will work if the DBM library is installed in the standard
1692place. Sometimes it is not, and the library's header file may also not be in
1693the default path. You may need to set INCLUDE to specify where the header
1694file is, and to specify the path to the library more fully in DBMLIB, as in
1695this example:
9b371988
PH
1696.code
1697INCLUDE=-I/usr/local/include/db-4.1
1698DBMLIB=/usr/local/lib/db-4.1/libdb.a
1699.endd
168e428f 1700There is further detailed discussion about the various DBM libraries in the
9b371988 1701file &_doc/dbm.discuss.txt_& in the Exim distribution.
168e428f
PH
1702
1703
1704
9b371988
PH
1705.section "Pre-building configuration"
1706.cindex "building Exim" "pre-building configuration"
1707.cindex "configuration for building Exim"
1708.cindex "&_Local/Makefile_&"
1709.cindex "&_src/EDITME_&"
168e428f
PH
1710Before building Exim, a local configuration file that specifies options
1711independent of any operating system has to be created with the name
9b371988
PH
1712&_Local/Makefile_&. A template for this file is supplied as the file
1713&_src/EDITME_&, and it contains full descriptions of all the option settings
168e428f
PH
1714therein. These descriptions are therefore not repeated here. If you are
1715building Exim for the first time, the simplest thing to do is to copy
9b371988 1716&_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
168e428f
PH
1717
1718There are three settings that you must supply, because Exim will not build
1719without them. They are the location of the run time configuration file
1720(CONFIGURE_FILE), the directory in which Exim binaries will be installed
1721(BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1722maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1723a colon-separated list of file names; Exim uses the first of them that exists.
1724
1725There are a few other parameters that can be specified either at build time or
1726at run time, to enable the same binary to be used on a number of different
1727machines. However, if the locations of Exim's spool directory and log file
1728directory (if not within the spool directory) are fixed, it is recommended that
9b371988 1729you specify them in &_Local/Makefile_& instead of at run time, so that errors
168e428f
PH
1730detected early in Exim's execution (such as a malformed configuration file) can
1731be logged.
1732
9b371988 1733.cindex "content scanning" "specifying at build time"
068aaea8 1734Exim's interfaces for calling virus and spam scanning software directly from
168e428f
PH
1735access control lists are not compiled by default. If you want to include these
1736facilities, you need to set
9b371988
PH
1737.code
1738WITH_CONTENT_SCAN=yes
1739.endd
1740in your &_Local/Makefile_&. For details of the facilities themselves, see
1741chapter &<<CHAPexiscan>>&.
168e428f
PH
1742
1743
9b371988
PH
1744.cindex "&_Local/eximon.conf_&"
1745.cindex "_exim_monitor/EDITME_"
168e428f 1746If you are going to build the Exim monitor, a similar configuration process is
9b371988
PH
1747required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1748your installation and saved under the name &_Local/eximon.conf_&. If you are
1749happy with the default settings described in &_exim_monitor/EDITME_&,
1750&_Local/eximon.conf_& can be empty, but it must exist.
168e428f
PH
1751
1752This is all the configuration that is needed in straightforward cases for known
1753operating systems. However, the building process is set up so that it is easy
1754to override options that are set by default or by operating-system-specific
1755configuration files, for example to change the name of the C compiler, which
9b371988
PH
1756defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1757do this.
168e428f
PH
1758
1759
1760
9b371988
PH
1761.section "Support for iconv()"
1762.cindex "&[iconv()]& support"
1763.cindex "RFC 2047"
168e428f
PH
1764The contents of header lines in messages may be encoded according to the rules
1765described RFC 2047. This makes it possible to transmit characters that are not
1766in the ASCII character set, and to label them as being in a particular
9b371988 1767character set. When Exim is inspecting header lines by means of the &%$h_%&
168e428f
PH
1768mechanism, it decodes them, and translates them into a specified character set
1769(default ISO-8859-1). The translation is possible only if the operating system
9b371988
PH
1770supports the &[iconv()]& function.
1771
1772However, some of the operating systems that supply &[iconv()]& do not support
1773very many conversions. The GNU &%libiconv%& library (available from
1774&url(http://www.gnu.org/software/libiconv/)) can be installed on such
1775systems to remedy this deficiency, as well as on systems that do not supply
1776&[iconv()]& at all. After installing &%libiconv%&, you should add
1777.code
1778HAVE_ICONV=yes
1779.endd
1780to your &_Local/Makefile_& and rebuild Exim.
1781
1782
1783
1784.section "Including TLS/SSL encryption support" "SECTinctlsssl"
1785.cindex "TLS" "including support for TLS"
1786.cindex "encryption" "including support for"
1787.cindex "SUPPORT_TLS"
1788.cindex "OpenSSL" "building Exim with"
1789.cindex "GnuTLS" "building Exim with"
168e428f
PH
1790Exim can be built to support encrypted SMTP connections, using the STARTTLS
1791command as per RFC 2487. It can also support legacy clients that expect to
1792start a TLS session immediately on connection to a non-standard port (see the
9b371988 1793&%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
168e428f
PH
1794line option).
1795
1796If you want to build Exim with TLS support, you must first install either the
1797OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1798implementing SSL.
1799
1800If OpenSSL is installed, you should set
9b371988
PH
1801.code
1802SUPPORT_TLS=yes
1803TLS_LIBS=-lssl -lcrypto
1804.endd
1805in &_Local/Makefile_&. You may also need to specify the locations of the
168e428f 1806OpenSSL library and include files. For example:
9b371988
PH
1807.code
1808SUPPORT_TLS=yes
1809TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1810TLS_INCLUDE=-I/usr/local/openssl/include/
1811.endd
1812.cindex "USE_GNUTLS"
168e428f 1813If GnuTLS is installed, you should set
9b371988
PH
1814.code
1815SUPPORT_TLS=yes
1816USE_GNUTLS=yes
1817TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1818.endd
1819in &_Local/Makefile_&, and again you may need to specify the locations of the
168e428f 1820library and include files. For example:
9b371988
PH
1821.code
1822SUPPORT_TLS=yes
1823USE_GNUTLS=yes
1824TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1825TLS_INCLUDE=-I/usr/gnu/include
1826.endd
168e428f 1827You do not need to set TLS_INCLUDE if the relevant directory is already
9b371988
PH
1828specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1829given in chapter &<<CHAPTLS>>&.
168e428f
PH
1830
1831
1832
1833
9b371988
PH
1834.section "Use of tcpwrappers"
1835.cindex "tcpwrappers" "building Exim to support"
1836.cindex "USE_TCP_WRAPPERS"
1837Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1838SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
168e428f 1839alternative to Exim's own checking facilities for installations that are
9b371988
PH
1840already making use of &'tcpwrappers'& for other purposes. To do this, you
1841should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1842&_tcpd.h_& to be available at compile time, and also ensure that the library
1843&_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1844EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1845you might have
1846.code
1847USE_TCP_WRAPPERS=yes
1848CFLAGS=-O -I/usr/local/include
1849EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1850.endd
1851in &_Local/Makefile_&. The name to use in the &'tcpwrappers'& control files is
1852&"exim"&. For example, the line
1853.code
1854exim : LOCAL 192.168.1. .friendly.domain.example
1855.endd
1856in your &_/etc/hosts.allow_& file allows connections from the local host, from
1857the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&.
1858All other connections are denied. Consult the &'tcpwrappers'& documentation for
168e428f
PH
1859further details.
1860
1861
1862
9b371988
PH
1863.section "Including support for IPv6"
1864.cindex "IPv6" "including support for"
168e428f 1865Exim contains code for use on systems that have IPv6 support. Setting
9b371988 1866&`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
168e428f
PH
1867it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1868where the IPv6 support is not fully integrated into the normal include and
1869library files.
1870
1871Two different types of DNS record for handling IPv6 addresses have been
1872defined. AAAA records (analagous to A records for IPv4) are in use, and are
1873currently seen as the mainstream. Another record type called A6 was proposed
1874as better than AAAA because it had more flexibility. However, it was felt to be
9b371988 1875over-complex, and its status was reduced to &"experimental"&. It is not known
168e428f 1876if anyone is actually using A6 records. Exim has support for A6 records, but
9b371988 1877this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
168e428f
PH
1878support has not been tested for some time.
1879
1880
1881
9b371988
PH
1882.section "The building process"
1883.cindex "build directory"
1884Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
1885created, run &'make'& at the top level. It determines the architecture and
168e428f
PH
1886operating system types, and creates a build directory if one does not exist.
1887For example, on a Sun system running Solaris 8, the directory
9b371988
PH
1888&_build-SunOS5-5.8-sparc_& is created.
1889.cindex "symbolic link" "to source files"
168e428f
PH
1890Symbolic links to relevant source files are installed in the build directory.
1891
9b371988 1892&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
168e428f
PH
1893building process fails if it is set.
1894
9b371988 1895If this is the first time &'make'& has been run, it calls a script that builds
168e428f 1896a make file inside the build directory, using the configuration files from the
9b371988
PH
1897&_Local_& directory. The new make file is then passed to another instance of
1898&'make'&. This does the real work, building a number of utility scripts, and
168e428f 1899then compiling and linking the binaries for the Exim monitor (if configured), a
9b371988
PH
1900number of utility programs, and finally Exim itself. The command &`make
1901makefile`& can be used to force a rebuild of the make file in the build
168e428f
PH
1902directory, should this ever be necessary.
1903
1904If you have problems building Exim, check for any comments there may be in the
9b371988 1905&_README_& file concerning your operating system, and also take a look at the
168e428f
PH
1906FAQ, where some common problems are covered.
1907
1908
1909
9b371988 1910.section 'Output from &"make"&'
9b371988 1911The output produced by the &'make'& process for compile lines is often very
068aaea8
PH
1912unreadable, because these lines can be very long. For this reason, the normal
1913output is suppressed by default, and instead output similar to that which
1914appears when compiling the 2.6 Linux kernel is generated: just a short line for
1915each module that is being compiled or linked. However, it is still possible to
9b371988
PH
1916get the full output, by calling &'make'& like this:
1917.code
1918FULLECHO='' make -e
1919.endd
1920The value of FULLECHO defaults to &"@"&, the flag character that suppresses
1921command reflection in &'make'&. When you ask for the full output, it is
068aaea8
PH
1922given in addition to the the short output.
1923
1924
1925
9b371988
PH
1926.section "Overriding build-time options for Exim" "SECToverride"
1927.cindex "build-time options" "overriding"
168e428f
PH
1928The main make file that is created at the beginning of the building process
1929consists of the concatenation of a number of files which set configuration
9b371988 1930values, followed by a fixed set of &'make'& instructions. If a value is set
168e428f
PH
1931more than once, the last setting overrides any previous ones. This provides a
1932convenient way of overriding defaults. The files that are concatenated are, in
1933order:
9b371988
PH
1934.display
1935&_OS/Makefile-Default_&
1936&_OS/Makefile-_&<&'ostype'&>
1937&_Local/Makefile_&
1938&_Local/Makefile-_&<&'ostype'&>
1939&_Local/Makefile-_&<&'archtype'&>
1940&_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
1941&_OS/Makefile-Base_&
1942.endd
1943.cindex "&_Local/Makefile_&"
1944.cindex "building Exim" "operating system type"
1945.cindex "building Exim" "architecture type"
1946where <&'ostype'&> is the operating system type and <&'archtype'&> is the
1947architecture type. &_Local/Makefile_& is required to exist, and the building
1948process fails if it is absent. The other three &_Local_& files are optional,
168e428f
PH
1949and are often not needed.
1950
9b371988
PH
1951The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
1952called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
168e428f
PH
1953the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
1954values are used, thereby providing a means of forcing particular settings.
9b371988 1955Otherwise, the scripts try to get values from the &%uname%& command. If this
168e428f 1956fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
9b371988 1957of &'ad hoc'& transformations are then applied, to produce the standard names
168e428f
PH
1958that Exim expects. You can run these scripts directly from the shell in order
1959to find out what values are being used on your system.
1960
1961
9b371988 1962&_OS/Makefile-Default_& contains comments about the variables that are set
168e428f
PH
1963therein. Some (but not all) are mentioned below. If there is something that
1964needs changing, review the contents of this file and the contents of the make
9b371988 1965file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
168e428f
PH
1966default values are.
1967
1968
9b371988
PH
1969.cindex "building Exim" "overriding default settings"
1970If you need to change any of the values that are set in &_OS/Makefile-Default_&
1971or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
168e428f 1972need to change the original files. Instead, you should make the changes by
9b371988
PH
1973putting the new values in an appropriate &_Local_& file. For example,
1974.cindex "Tru64-Unix build-time settings"
168e428f
PH
1975when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
1976formerly DEC-OSF1) operating system, it is necessary to specify that the C
9b371988
PH
1977compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
1978called with the option &%-std1%&, to make it recognize some of the features of
168e428f 1979Standard C that Exim uses. (Most other compilers recognize Standard C by
9b371988 1980default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
168e428f 1981containing the lines
9b371988
PH
1982.code
1983CC=cc
1984CFLAGS=-std1
1985.endd
168e428f 1986If you are compiling for just one operating system, it may be easier to put
9b371988 1987these lines directly into &_Local/Makefile_&.
168e428f
PH
1988
1989Keeping all your local configuration settings separate from the distributed
1990files makes it easy to transfer them to new versions of Exim simply by copying
9b371988 1991the contents of the &_Local_& directory.
168e428f
PH
1992
1993
9b371988
PH
1994.cindex "NIS lookup type" "including support for"
1995.cindex "NIS+ lookup type" "including support for"
1996.cindex "LDAP" "including support for"
1997.cindex "lookup" "inclusion in binary"
168e428f
PH
1998Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
1999lookup, but not all systems have these components installed, so the default is
2000not to include the relevant code in the binary. All the different kinds of file
2001and database lookup that Exim supports are implemented as separate code modules
2002which are included only if the relevant compile-time options are set. In the
9b371988
PH
2003case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2004.code
2005LOOKUP_LDAP=yes
2006LOOKUP_NIS=yes
2007LOOKUP_NISPLUS=yes
2008.endd
168e428f 2009and similar settings apply to the other lookup types. They are all listed in
9b371988 2010&_src/EDITME_&. In many cases the relevant include files and interface
168e428f 2011libraries need to be installed before compiling Exim.
9b371988 2012.cindex "cdb" "including support for"
068aaea8
PH
2013However, there are some optional lookup types (such as cdb) for which
2014the code is entirely contained within Exim, and no external include
168e428f
PH
2015files or libraries are required. When a lookup type is not included in the
2016binary, attempts to configure Exim to use it cause run time configuration
2017errors.
2018
9b371988 2019.cindex "Perl" "including support for"
168e428f
PH
2020Exim can be linked with an embedded Perl interpreter, allowing Perl
2021subroutines to be called during string expansion. To enable this facility,
9b371988
PH
2022.code
2023EXIM_PERL=perl.o
2024.endd
2025must be defined in &_Local/Makefile_&. Details of this facility are given in
2026chapter &<<CHAPperl>>&.
168e428f 2027
9b371988 2028.cindex "X11 libraries" "location of"
168e428f 2029The location of the X11 libraries is something that varies a lot between
068aaea8 2030operating systems, and there may be different versions of X11 to cope
168e428f
PH
2031with. Exim itself makes no use of X11, but if you are compiling the Exim
2032monitor, the X11 libraries must be available.
9b371988
PH
2033The following three variables are set in &_OS/Makefile-Default_&:
2034.code
2035X11=/usr/X11R6
2036XINCLUDE=-I$(X11)/include
2037XLFLAGS=-L$(X11)/lib
2038.endd
168e428f 2039These are overridden in some of the operating-system configuration files. For
9b371988
PH
2040example, in &_OS/Makefile-SunOS5_& there is
2041.code
2042X11=/usr/openwin
2043XINCLUDE=-I$(X11)/include
2044XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2045.endd
168e428f
PH
2046If you need to override the default setting for your operating system, place a
2047definition of all three of these variables into your
9b371988 2048&_Local/Makefile-<ostype>_& file.
168e428f 2049
9b371988 2050.cindex "EXTRALIBS"
168e428f
PH
2051If you need to add any extra libraries to the link steps, these can be put in a
2052variable called EXTRALIBS, which appears in all the link commands, but by
2053default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2054command for linking the main Exim binary, and not for any associated utilities.
2055
9b371988 2056.cindex "DBM libraries" "configuration for building"
168e428f 2057There is also DBMLIB, which appears in the link commands for binaries that
9b371988 2058use DBM functions (see also section &<<SECTdb>>&). Finally, there is
168e428f
PH
2059EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2060binary, and which can be used, for example, to include additional X11
2061libraries.
2062
9b371988 2063.cindex "configuration file" "editing"
168e428f
PH
2064The make file copes with rebuilding Exim correctly if any of the configuration
2065files are edited. However, if an optional configuration file is deleted, it is
9b371988
PH
2066necessary to touch the associated non-optional file (that is,
2067&_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
168e428f
PH
2068
2069
9b371988
PH
2070.section "OS-specific header files"
2071.cindex "&_os.h_&"
2072.cindex "building Exim" "OS-specific C header files"
2073The &_OS_& directory contains a number of files with names of the form
2074&_os.h-<ostype>_&. These are system-specific C header files that should not
168e428f 2075normally need to be changed. There is a list of macro settings that are
9b371988 2076recognized in the file &_OS/os.configuring_&, which should be consulted if you
168e428f
PH
2077are porting Exim to a new operating system.
2078
2079
2080
9b371988
PH
2081.section "Overriding build-time options for the monitor"
2082.cindex "building Eximon" "overriding default options"
168e428f
PH
2083A similar process is used for overriding things when building the Exim monitor,
2084where the files that are involved are
9b371988
PH
2085.display
2086&_OS/eximon.conf-Default_&
2087&_OS/eximon.conf-_&<&'ostype'&>
2088&_Local/eximon.conf_&
2089&_Local/eximon.conf-_&<&'ostype'&>
2090&_Local/eximon.conf-_&<&'archtype'&>
2091&_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2092.endd
2093.cindex "&_Local/eximon.conf_&"
168e428f 2094As with Exim itself, the final three files need not exist, and in this case the
9b371988
PH
2095&_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2096&_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
168e428f
PH
2097variables of the same name, preceded by EXIMON_. For example, setting
2098EXIMON_LOG_DEPTH in the environment overrides the value of
2099LOG_DEPTH at run time.
4f578862 2100.ecindex IIDbuex
168e428f
PH
2101
2102
9b371988
PH
2103.section "Installing Exim binaries and scripts"
2104.cindex "installing Exim"
2105.cindex "BIN_DIRECTORY"
2106The command &`make install`& runs the &(exim_install)& script with no
2107arguments. The script copies binaries and utility scripts into the directory
2108whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2109.cindex "setuid" "installing Exim with"
068aaea8
PH
2110The install script copies files only if they are newer than the files they are
2111going to replace. The Exim binary is required to be owned by root and have the
9b371988
PH
2112&'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2113install`& as root so that it can set up the Exim binary in this way. However, in
068aaea8
PH
2114some special situations (for example, if a host is doing no local deliveries)
2115it may be possible to run Exim without making the binary setuid root (see
9b371988 2116chapter &<<CHAPsecurity>>& for details).
168e428f 2117
9b371988 2118.cindex "CONFIGURE_FILE"
168e428f 2119Exim's run time configuration file is named by the CONFIGURE_FILE setting
9b371988
PH
2120in &_Local/Makefile_&. If this names a single file, and the file does not
2121exist, the default configuration file &_src/configure.default_& is copied there
168e428f
PH
2122by the installation script. If a run time configuration file already exists, it
2123is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2124alternative files, no default is installed.
2125
9b371988
PH
2126.cindex "system aliases file"
2127.cindex "&_/etc/aliases_&"
168e428f
PH
2128One change is made to the default configuration file when it is installed: the
2129default configuration contains a router that references a system aliases file.
2130The path to this file is set to the value specified by
9b371988 2131SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
168e428f
PH
2132If the system aliases file does not exist, the installation script creates it,
2133and outputs a comment to the user.
2134
2135The created file contains no aliases, but it does contain comments about the
2136aliases a site should normally have. Mail aliases have traditionally been
9b371988
PH
2137kept in &_/etc/aliases_&. However, some operating systems are now using
2138&_/etc/mail/aliases_&. You should check if yours is one of these, and change
168e428f
PH
2139Exim's configuration if necessary.
2140
2141The default configuration uses the local host's name as the only local domain,
9b371988
PH
2142and is set up to do local deliveries into the shared directory &_/var/mail_&,
2143running as the local user. System aliases and &_.forward_& files in users' home
168e428f
PH
2144directories are supported, but no NIS or NIS+ support is configured. Domains
2145other than the name of the local host are routed using the DNS, with delivery
2146over SMTP.
2147
168e428f
PH
2148It is possible to install Exim for special purposes (such as building a binary
2149distribution) in a private part of the file system. You can do this by a
2150command such as
9b371988
PH
2151.code
2152make DESTDIR=/some/directory/ install
2153.endd
168e428f
PH
2154This has the effect of pre-pending the specified directory to all the file
2155paths, except the name of the system aliases file that appears in the default
9b371988 2156configuration. (If a default alias file is created, its name &'is'& modified.)
168e428f
PH
2157For backwards compatibility, ROOT is used if DESTDIR is not set,
2158but this usage is deprecated.
2159
9b371988
PH
2160.cindex "installing Exim" "what is not installed"
2161Running &'make install'& does not copy the Exim 4 conversion script
2162&'convert4r4'&, or the &'pcretest'& test program. You will probably run the
168e428f 2163first of these only once (if you are upgrading from Exim 3), and the second
9b371988 2164isn't really part of Exim. None of the documentation files in the &_doc_&
168e428f 2165directory are copied, except for the info files when you have set
9b371988 2166INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
168e428f 2167
9b371988 2168For the utility programs, old versions are renamed by adding the suffix &_.O_&
168e428f
PH
2169to their names. The Exim binary itself, however, is handled differently. It is
2170installed under a name that includes the version number and the compile number,
9b371988
PH
2171for example &_exim-&version;-1_&. The script then arranges for a symbolic link
2172called &_exim_& to point to the binary. If you are updating a previous version
2173of Exim, the script takes care to ensure that the name &_exim_& is never absent
168e428f
PH
2174from the directory (as seen by other processes).
2175
9b371988
PH
2176.cindex "installing Exim" "testing the script"
2177If you want to see what the &'make install'& will do before running it for
2178real, you can pass the &%-n%& option to the installation script by this
2179command:
2180.code
2181make INSTALL_ARG=-n install
2182.endd
168e428f
PH
2183The contents of the variable INSTALL_ARG are passed to the installation
2184script. You do not need to be root to run this test. Alternatively, you can run
2185the installation script directly, but this must be from within the build
2186directory. For example, from the top-level Exim directory you could use this
2187command:
9b371988
PH
2188.code
2189(cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2190.endd
2191.cindex "installing Exim" "install script options"
168e428f
PH
2192There are two other options that can be supplied to the installation script.
2193
9b371988
PH
2194.ilist
2195&%-no_chown%& bypasses the call to change the owner of the installed binary
168e428f 2196to root, and the call to make it a setuid binary.
9b371988
PH
2197.next
2198&%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
168e428f 2199installed binary.
9b371988 2200.endlist
168e428f
PH
2201
2202INSTALL_ARG can be used to pass these options to the script. For example:
9b371988
PH
2203.code
2204make INSTALL_ARG=-no_symlink install
2205.endd
168e428f
PH
2206The installation script can also be given arguments specifying which files are
2207to be copied. For example, to install just the Exim binary, and nothing else,
2208without creating the symbolic link, you could use:
9b371988
PH
2209.code
2210make INSTALL_ARG='-no_symlink exim' install
2211.endd
168e428f
PH
2212
2213
2214
9b371988
PH
2215.section "Installing info documentation" "SECTinsinfdoc"
2216.cindex "installing Exim" "&'info'& documentation"
2217Not all systems use the GNU &'info'& system for documentation, and for this
168e428f
PH
2218reason, the Texinfo source of Exim's documentation is not included in the main
2219distribution. Instead it is available separately from the ftp site (see section
9b371988 2220&<<SECTavail>>&).
168e428f 2221
9b371988
PH
2222If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2223source of the documentation is found in the source tree, running &`make
2224install`& automatically builds the info files and installs them.
168e428f
PH
2225
2226
2227
9b371988
PH
2228.section "Setting up the spool directory"
2229.cindex "spool directory" "creating"
168e428f
PH
2230When it starts up, Exim tries to create its spool directory if it does not
2231exist. The Exim uid and gid are used for the owner and group of the spool
2232directory. Sub-directories are automatically created in the spool directory as
2233necessary.
2234
2235
2236
2237
9b371988
PH
2238.section "Testing"
2239.cindex "testing" "installation"
168e428f
PH
2240Having installed Exim, you can check that the run time configuration file is
2241syntactically valid by running the following command, which assumes that the
2242Exim binary directory is within your PATH environment variable:
9b371988
PH
2243.code
2244exim -bV
2245.endd
168e428f
PH
2246If there are any errors in the configuration file, Exim outputs error messages.
2247Otherwise it outputs the version number and build date,
2248the DBM library that is being used, and information about which drivers and
2249other optional code modules are included in the binary.
2250Some simple routing tests can be done by using the address testing option. For
2251example,
9b371988
PH
2252.display
2253&`exim -bt`& <&'local username'&>
2254.endd
168e428f 2255should verify that it recognizes a local mailbox, and
9b371988
PH
2256.display
2257&`exim -bt`& <&'remote address'&>
2258.endd
168e428f
PH
2259a remote one. Then try getting it to deliver mail, both locally and remotely.
2260This can be done by passing messages directly to Exim, without going through a
2261user agent. For example:
9b371988 2262.code
068aaea8
PH
2263exim -v postmaster@your.domain.example
2264From: user@your.domain.example
2265To: postmaster@your.domain.example
2266Subject: Testing Exim
168e428f 2267
068aaea8
PH
2268This is a test message.
2269^D
9b371988
PH
2270.endd
2271The &%-v%& option causes Exim to output some verification of what it is doing.
168e428f 2272In this case you should see copies of three log lines, one for the message's
9b371988 2273arrival, one for its delivery, and one containing &"Completed"&.
168e428f 2274
9b371988
PH
2275.cindex "delivery" "problems with"
2276If you encounter problems, look at Exim's log files (&'mainlog'& and
2277&'paniclog'&) to see if there is any relevant information there. Another source
168e428f 2278of information is running Exim with debugging turned on, by specifying the
9b371988 2279&%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
168e428f 2280with debugging turned on by a command of the form
9b371988
PH
2281.display
2282&`exim -d -M`& <&'exim-message-id'&>
2283.endd
2284You must be root or an &"admin user"& in order to do this. The &%-d%& option
168e428f 2285produces rather a lot of output, but you can cut this down to specific areas.
9b371988
PH
2286For example, if you use &%-d-all+route%& only the debugging information
2287relevant to routing is included. (See the &%-d%& option in chapter
2288&<<CHAPcommandline>>& for more details.)
168e428f 2289
9b371988
PH
2290.cindex '&"sticky"& bit'
2291.cindex "lock files"
168e428f
PH
2292One specific problem that has shown up on some sites is the inability to do
2293local deliveries into a shared mailbox directory, because it does not have the
9b371988 2294&"sticky bit"& set on it. By default, Exim tries to create a lock file before
168e428f 2295writing to a mailbox file, and if it cannot create the lock file, the delivery
9b371988 2296is deferred. You can get round this either by setting the &"sticky bit"& on the
168e428f
PH
2297directory, or by setting a specific group for local deliveries and allowing
2298that group to create files in the directory (see the comments above the
9b371988 2299&(local_delivery)& transport in the default configuration file). Another
168e428f 2300approach is to configure Exim not to use lock files, but just to rely on
9b371988
PH
2301&[fcntl()]& locking instead. However, you should do this only if all user
2302agents also use &[fcntl()]& locking. For further discussion of locking issues,
2303see chapter &<<CHAPappendfile>>&.
168e428f
PH
2304
2305One thing that cannot be tested on a system that is already running an MTA is
2306the receipt of incoming SMTP mail on the standard SMTP port. However, the
9b371988
PH
2307&%-oX%& option can be used to run an Exim daemon that listens on some other
2308port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2309&'exim_checkaccess'& utility can be used to check out policy controls on
168e428f
PH
2310incoming SMTP mail.
2311
2312Testing a new version on a system that is already running Exim can most easily
2313be done by building a binary with a different CONFIGURE_FILE setting. From
2314within the run time configuration, all other file and directory names
2315that Exim uses can be altered, in order to keep it entirely clear of the
2316production version.
2317
2318
9b371988
PH
2319.section "Replacing another MTA with Exim"
2320.cindex "replacing another MTA"
168e428f
PH
2321Building and installing Exim for the first time does not of itself put it in
2322general use. The name by which the system's MTA is called by mail user agents
9b371988
PH
2323is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2324operating system), and it is necessary to make this name point to the &'exim'&
168e428f 2325binary in order to get the user agents to pass messages to Exim. This is
9b371988
PH
2326normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2327or &_/usr/lib/sendmail_&
2328.cindex "symbolic link" "to &'exim'& binary"
2329a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
168e428f
PH
2330privilege and executable status from the old MTA. It is then necessary to stop
2331and restart the mailer daemon, if one is running.
2332
9b371988
PH
2333.cindex "FreeBSD" "MTA indirection"
2334.cindex "&_/etc/mail/mailer.conf_&"
168e428f
PH
2335Some operating systems have introduced alternative ways of switching MTAs. For
2336example, if you are running FreeBSD, you need to edit the file
9b371988 2337&_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
168e428f
PH
2338described. A typical example of the contents of this file for running Exim is
2339as follows:
9b371988
PH
2340.code
2341sendmail /usr/exim/bin/exim
2342send-mail /usr/exim/bin/exim
2343mailq /usr/exim/bin/exim -bp
2344newaliases /usr/bin/true
2345.endd
2346Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2347your Exim installation is &"live"&. Check it by sending a message from your
168e428f
PH
2348favourite user agent.
2349
2350You should consider what to tell your users about the change of MTA. Exim may
2351have different capabilities to what was previously running, and there are
2352various operational differences such as the text of messages produced by
2353command line options and in bounce messages. If you allow your users to make
2354use of Exim's filtering capabilities, you should make the document entitled
9b371988 2355&'Exim's interface to mail filtering'& available to them.
168e428f
PH
2356
2357
2358
9b371988
PH
2359.section "Upgrading Exim"
2360.cindex "upgrading Exim"
168e428f
PH
2361If you are already running Exim on your host, building and installing a new
2362version automatically makes it available to MUAs, or any other programs that
2363call the MTA directly. However, if you are running an Exim daemon, you do need
9b371988
PH
2364to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2365new binary. You do not need to stop processing mail in order to install a new
068aaea8
PH
2366version of Exim. The install script does not modify an existing runtime
2367configuration file.
2368
168e428f
PH
2369
2370
2371
9b371988
PH
2372.section "Stopping the Exim daemon on Solaris"
2373.cindex "Solaris" "stopping Exim on"
168e428f 2374The standard command for stopping the mailer daemon on Solaris is
9b371988
PH
2375.code
2376/etc/init.d/sendmail stop
2377.endd
2378If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2379fails to stop Exim because it uses the command &'ps -e'& and greps the output
2380for the text &"sendmail"&; this is not present because the actual program name
2381(that is, &"exim"&) is given by the &'ps'& command with these options. A
2382solution is to replace the line that finds the process id with something like
2383.code
2384pid=`cat /var/spool/exim/exim-daemon.pid`
2385.endd
168e428f
PH
2386to obtain the daemon's pid directly from the file that Exim saves it in.
2387
9b371988 2388Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
168e428f
PH
2389still be received from local processes, and if automatic delivery is configured
2390(the normal case), deliveries will still occur.
2391
2392
2393
2394
9b371988
PH
2395. ////////////////////////////////////////////////////////////////////////////
2396. ////////////////////////////////////////////////////////////////////////////
168e428f 2397
9b371988 2398.chapter "The Exim command line" "CHAPcommandline"
4f578862
PH
2399.scindex IIDclo1 "command line" "options"
2400.scindex IIDclo2 "options" "command line"
168e428f
PH
2401Exim's command line takes the standard Unix form of a sequence of options,
2402each starting with a hyphen character, followed by a number of arguments. The
2403options are compatible with the main options of Sendmail, and there are also
2404some additional options, some of which are compatible with Smail 3. Certain
2405combinations of options do not make sense, and provoke an error if used.
2406The form of the arguments depends on which options are set.
2407
2408
9b371988
PH
2409.section "Setting options by program name"
2410.cindex "&'mailq'&"
2411If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
168e428f 2412were present before any other options.
9b371988 2413The &%-bp%& option requests a listing of the contents of the mail queue on the
168e428f
PH
2414standard output.
2415This feature is for compatibility with some systems that contain a command of
2416that name in one of the standard libraries, symbolically linked to
9b371988
PH
2417&_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2418
2419.cindex "&'rsmtp'&"
2420If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2421were present before any other options, for compatibility with Smail. The
2422&%-bS%& option is used for reading in a number of messages in batched SMTP
2423format.
2424
2425.cindex "&'rmail'&"
2426If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2427&%-oee%& options were present before any other options, for compatibility with
2428Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2429
2430.cindex "&'runq'&"
2431.cindex "queue runner"
2432If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2433were present before any other options, for compatibility with Smail. The &%-q%&
168e428f
PH
2434option causes a single queue runner process to be started.
2435
9b371988
PH
2436.cindex "&'newaliases'&"
2437.cindex "alias file" "building"
2438.cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2439If Exim is called under the name &'newaliases'& it behaves as if the option
2440&%-bi%& were present before any other options, for compatibility with Sendmail.
168e428f
PH
2441This option is used for rebuilding Sendmail's alias file. Exim does not have
2442the concept of a single alias file, but can be configured to run a given
9b371988 2443command if called with the &%-bi%& option.
168e428f
PH
2444
2445
9b371988
PH
2446.section "Trusted and admin users" "SECTtrustedadmin"
2447Some Exim options are available only to &'trusted users'& and others are
2448available only to &'admin users'&. In the description below, the phrases &"Exim
2449user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2450EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2451&%exim_group%& options. These do not necessarily have to use the name &"exim"&.
168e428f 2452
9b371988
PH
2453.ilist
2454.cindex "trusted user" "definition of"
2455.cindex "user" "trusted definition of"
168e428f 2456The trusted users are root, the Exim user, any user listed in the
9b371988
PH
2457&%trusted_users%& configuration option, and any user whose current group or any
2458supplementary group is one of those listed in the &%trusted_groups%&
168e428f 2459configuration option. Note that the Exim group is not automatically trusted.
9b371988
PH
2460
2461.cindex '&"From"& line'
2462.cindex "envelope sender"
2463Trusted users are always permitted to use the &%-f%& option or a leading
2464&"From&~"& line to specify the envelope sender of a message that is passed to
2465Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2466See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2467users to set envelope senders.
2468
2469.cindex "&'From:'& header line"
2470.cindex "&'Sender:'& header line"
2471For a trusted user, there is never any check on the contents of the &'From:'&
2472header line, and a &'Sender:'& line is never added. Furthermore, any existing
2473&'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2474
168e428f
PH
2475Trusted users may also specify a host name, host address, interface address,
2476protocol name, ident value, and authentication data when submitting a message
2477locally. Thus, they are able to insert messages into Exim's queue locally that
2478have the characteristics of messages received from a remote host. Untrusted
9b371988 2479users may in some circumstances use &%-f%&, but can never set the other values
168e428f 2480that are available to trusted users.
9b371988
PH
2481.next
2482.cindex "user" "admin definition of"
2483.cindex "admin user" "definition of"
168e428f 2484The admin users are root, the Exim user, and any user that is a member of the
9b371988 2485Exim group or of any group listed in the &%admin_groups%& configuration option.
168e428f 2486The current group does not have to be one of these groups.
9b371988 2487
168e428f
PH
2488Admin users are permitted to list the queue, and to carry out certain
2489operations on messages, for example, to force delivery failures. It is also
2490necessary to be an admin user in order to see the full information provided by
2491the Exim monitor, and full debugging output.
9b371988
PH
2492
2493By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2494Exim to attempt delivery of messages on its queue is restricted to admin users.
2495However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2496option false (that is, specifying &%no_prod_requires_admin%&).
2497
2498Similarly, the use of the &%-bp%& option to list all the messages in the queue
2499is restricted to admin users unless &%queue_list_requires_admin%& is set
168e428f 2500false.
9b371988 2501.endlist
168e428f
PH
2502
2503
9b371988 2504&*Warning*&: If you configure your system so that admin users are able to
168e428f
PH
2505edit Exim's configuration file, you are giving those users an easy way of
2506getting root. There is further discussion of this issue at the start of chapter
9b371988 2507&<<CHAPconf>>&.
168e428f
PH
2508
2509
2510
2511
9b371988 2512.section "Command line options"
168e428f
PH
2513The command options are described in alphabetical order below.
2514
9b371988
PH
2515. ////////////////////////////////////////////////////////////////////////////
2516. Insert a stylized XML comment here, to identify the start of the command line
2517. options. This is for the benefit of the Perl script that automatically
2518. creates a man page for the options.
2519. ////////////////////////////////////////////////////////////////////////////
168e428f 2520
9b371988 2521.literal xml
168e428f 2522<!-- === Start of command line options === -->
9b371988 2523.literal off
168e428f
PH
2524
2525
9b371988
PH
2526.vlist
2527.vitem &%--%&
2528.oindex "--"
2529.cindex "options" "command line; terminating"
168e428f
PH
2530This is a pseudo-option whose only purpose is to terminate the options and
2531therefore to cause subsequent command line items to be treated as arguments
2532rather than options, even if they begin with hyphens.
2533
9b371988
PH
2534.vitem &%--help%&
2535.oindex "&%--help%&"
168e428f
PH
2536This option causes Exim to output a few sentences stating what it is.
2537The same output is generated if the Exim binary is called with no options and
2538no arguments.
2539
9b371988
PH
2540.vitem &%-B%&<&'type'&>
2541.oindex "&%-B%&"
2542.cindex "8-bit characters"
2543.cindex "Sendmail compatibility" "8-bit characters"
168e428f
PH
2544This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2545clean; it ignores this option.
2546
9b371988
PH
2547.vitem &%-bd%&
2548.oindex "&%-bd%&"
2549.cindex "daemon"
2550.cindex "SMTP listener"
2551.cindex "queue runner"
168e428f 2552This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
9b371988
PH
2553the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2554that the daemon should also initiate periodic queue runs.
2555
2556The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2557(debugging) or &%-v%& (verifying) options are set, the daemon does not
168e428f
PH
2558disconnect from the controlling terminal. When running this way, it can be
2559stopped by pressing ctrl-C.
9b371988 2560
168e428f
PH
2561By default, Exim listens for incoming connections to the standard SMTP port on
2562all the host's running interfaces. However, it is possible to listen on other
2563ports, on multiple ports, and only on specific interfaces. Chapter
9b371988
PH
2564&<<CHAPinterfaces>>& contains a description of the options that control this.
2565
168e428f 2566When a listening daemon
9b371988
PH
2567.cindex "daemon" "process id (pid)"
2568.cindex "pid (process id)" "of daemon"
2569is started without the use of &%-oX%& (that is, without overriding the normal
2570configuration), it writes its process id to a file called &_exim-daemon.pid_&
2571in Exim's spool directory. This location can be overridden by setting
2572PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
168e428f 2573running as root.
9b371988
PH
2574
2575When &%-oX%& is used on the command line to start a listening daemon, the
2576process id is not written to the normal pid file path. However, &%-oP%& can be
168e428f 2577used to specify a path on the command line if a pid file is required.
9b371988 2578
168e428f 2579The SIGHUP signal
9b371988 2580.cindex "SIGHUP"
168e428f
PH
2581can be used to cause the daemon to re-exec itself. This should be done whenever
2582Exim's configuration file, or any file that is incorporated into it by means of
9b371988
PH
2583the &%.include%& facility, is changed, and also whenever a new version of Exim
2584is installed. It is not necessary to do this when other files that are
2585referenced from the configuration (for example, alias files) are changed,
2586because these are reread each time they are used.
2587
2588.vitem &%-bdf%&
2589.oindex "&%-bdf%&"
2590This option has the same effect as &%-bd%& except that it never disconnects
2591from the controlling terminal, even when no debugging is specified.
2592
2593.vitem &%-be%&
2594.oindex "&%-be%&"
2595.cindex "testing" "string expansion"
2596.cindex "expansion" "testing"
168e428f
PH
2597Run Exim in expansion testing mode. Exim discards its root privilege, to
2598prevent ordinary users from using this mode to read otherwise inaccessible
2599files. If no arguments are given, Exim runs interactively, prompting for lines
4f578862 2600of data. Otherwise, it processes each argument in turn.
9b371988
PH
2601
2602If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2603to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2604used without command line arguments. If successful, it uses the &[readline()]&
168e428f
PH
2605function, which provides extensive line-editing facilities, for reading the
2606test data. A line history is supported.
9b371988 2607
168e428f 2608Long expansion expressions can be split over several lines by using backslash
068aaea8 2609continuations. As in Exim's run time configuration, white space at the start of
168e428f
PH
2610continuation lines is ignored. Each argument or data line is passed through the
2611string expansion mechanism, and the result is output. Variable values from the
9b371988
PH
2612configuration file (for example, &$qualify_domain$&) are available, but no
2613message-specific values (such as &$domain$&) are set, because no message is
168e428f
PH
2614being processed.
2615
9b371988
PH
2616&*Note*&: If you use this mechanism to test lookups, and you change the data
2617files or databases you are using, you must exit and restart Exim before trying
2618the same lookup again. Otherwise, because each Exim process caches the results
2619of lookups, you will just get the same result as before.
9b371988
PH
2620
2621.vitem &%-bF%&&~<&'filename'&>
2622.oindex "&%-bF%&"
2623.cindex "system filter" "testing"
2624.cindex "testing" "system filter"
2625This option is the same as &%-bf%& except that it assumes that the filter being
168e428f
PH
2626tested is a system filter. The additional commands that are available only in
2627system filters are recognized.
2628
9b371988
PH
2629.vitem &%-bf%&&~<&'filename'&>
2630.oindex "&%-bf%&"
2631.cindex "filter" "testing"
2632.cindex "testing" "filter file"
2633.cindex "forward file" "testing"
2634.cindex "testing" "forward file"
2635.cindex "Sieve filter" "testing"
168e428f
PH
2636This option runs Exim in user filter testing mode; the file is the filter file
2637to be tested, and a test message must be supplied on the standard input. If
2638there are no message-dependent tests in the filter, an empty file can be
2639supplied.
168e428f 2640
9b371988
PH
2641If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2642can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2643filter and a user filter in the same run. For example:
2644.code
2645exim -bF /system/filter -bf /user/filter </test/message
2646.endd
168e428f
PH
2647This is helpful when the system filter adds header lines or sets filter
2648variables that are used by the user filter.
168e428f 2649
9b371988
PH
2650If the test filter file does not begin with one of the special lines
2651.code
2652# Exim filter
2653# Sieve filter
2654.endd
2655it is taken to be a normal &_.forward_& file, and is tested for validity under
2656that interpretation. See sections &<<SECTitenonfilred>>& to
2657&<<SECTspecitredli>>& for a description of the possible contents of non-filter
2658redirection lists.
2659
2660The result of an Exim command that uses &%-bf%&, provided no errors are
168e428f
PH
2661detected, is a list of the actions that Exim would try to take if presented
2662with the message for real. More details of filter testing are given in the
9b371988
PH
2663separate document entitled &'Exim's interfaces to mail filtering'&.
2664
168e428f 2665When testing a filter file,
9b371988
PH
2666.cindex "&""From""& line"
2667.cindex "envelope sender"
2668.cindex "&%-f%& option" "for filter testing"
2669the envelope sender can be set by the &%-f%& option,
2670or by a &"From&~"& line at the start of the test message. Various parameters
2671that would normally be taken from the envelope recipient address of the message
2672can be set by means of additional command line options (see the next four
2673options).
2674
2675.vitem &%-bfd%&&~<&'domain'&>
2676.oindex "&%-bfd%&"
2677.cindex "&$qualify_domain$&"
168e428f 2678This sets the domain of the recipient address when a filter file is being
9b371988
PH
2679tested by means of the &%-bf%& option. The default is the value of
2680&$qualify_domain$&.
168e428f 2681
9b371988
PH
2682.vitem &%-bfl%&&~<&'local&~part'&>
2683.oindex "&%-bfl%&"
168e428f 2684This sets the local part of the recipient address when a filter file is being
9b371988 2685tested by means of the &%-bf%& option. The default is the username of the
168e428f
PH
2686process that calls Exim. A local part should be specified with any prefix or
2687suffix stripped, because that is how it appears to the filter when a message is
2688actually being delivered.
2689
9b371988
PH
2690.vitem &%-bfp%&&~<&'prefix'&>
2691.oindex "&%-bfp%&"
168e428f 2692This sets the prefix of the local part of the recipient address when a filter
9b371988 2693file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
PH
2694prefix.
2695
9b371988
PH
2696.vitem &%-bfs%&&~<&'suffix'&>
2697.oindex "&%-bfs%&"
168e428f 2698This sets the suffix of the local part of the recipient address when a filter
9b371988 2699file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
PH
2700suffix.
2701
9b371988
PH
2702.vitem &%-bh%&&~<&'IP&~address'&>
2703.oindex "&%-bh%&"
2704.cindex "testing" "incoming SMTP"
2705.cindex "SMTP" "testing incoming"
2706.cindex "testing" "relay control"
2707.cindex "relaying" "testing configuration"
2708.cindex "policy control" "testing"
2709.cindex "debugging" "&%-bh%& option"
168e428f
PH
2710This option runs a fake SMTP session as if from the given IP address, using the
2711standard input and output. The IP address may include a port number at the end,
2712after a full stop. For example:
9b371988
PH
2713.code
2714exim -bh 10.9.8.7.1234
2715exim -bh fe80::a00:20ff:fe86:a061.5678
2716.endd
168e428f 2717When an IPv6 address is given, it is converted into canonical form. In the case
9b371988
PH
2718of the second example above, the value of &$sender_host_address$& after
2719conversion to the canonical form is
2720&`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2721
168e428f 2722Comments as to what is going on are written to the standard error file. These
9b371988 2723include lines beginning with &"LOG"& for anything that would have been logged.
168e428f
PH
2724This facility is provided for testing configuration options for incoming
2725messages, to make sure they implement the required policy. For example, you can
9b371988
PH
2726test your relay controls using &%-bh%&.
2727
2728&*Warning 1*&:
2729.cindex "RFC 1413"
168e428f
PH
2730You cannot test features of the configuration that rely on
2731ident (RFC 1413) callouts. These cannot be done when testing using
9b371988
PH
2732&%-bh%& because there is no incoming SMTP connection.
2733
2734&*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2735are also skipped when testing using &%-bh%&. If you want these callouts to
2736occur, use &%-bhc%& instead.
2737
168e428f
PH
2738Messages supplied during the testing session are discarded, and nothing is
2739written to any of the real log files. There may be pauses when DNS (and other)
9b371988 2740lookups are taking place, and of course these may time out. The &%-oMi%& option
168e428f 2741can be used to specify a specific IP interface and port if this is important.
9b371988
PH
2742
2743The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
168e428f 2744output just states whether a given recipient address from a given host is
9b371988 2745acceptable or not. See section &<<SECTcheckaccess>>&.
168e428f 2746
9b371988
PH
2747.vitem &%-bhc%&&~<&'IP&~address'&>
2748.oindex "&%-bhc%&"
2749This option operates in the same way as &%-bh%&, except that address
168e428f
PH
2750verification callouts are performed if required. This includes consulting and
2751updating the callout cache database.
2752
9b371988
PH
2753.vitem &%-bi%&
2754.oindex "&%-bi%&"
2755.cindex "alias file" "building"
2756.cindex "building alias file"
2757.cindex "Sendmail compatibility" "&%-bi%& option"
2758Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
168e428f 2759Exim does not have the concept of a single alias file, and so it cannot mimic
9b371988 2760this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
168e428f
PH
2761tend to appear in various scripts such as NIS make files, so the option must be
2762recognized.
9b371988
PH
2763
2764If &%-bi%& is encountered, the command specified by the &%bi_command%&
168e428f 2765configuration option is run, under the uid and gid of the caller of Exim. If
9b371988
PH
2766the &%-oA%& option is used, its value is passed to the command as an argument.
2767The command set by &%bi_command%& may not contain arguments. The command can
2768use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2769if this is required. If the &%bi_command%& option is not set, calling Exim with
2770&%-bi%& is a no-op.
2771
2772.vitem &%-bm%&
2773.oindex "&%-bm%&"
2774.cindex "local message reception"
168e428f
PH
2775This option runs an Exim receiving process that accepts an incoming,
2776locally-generated message on the current input. The recipients are given as the
9b371988 2777command arguments (except when &%-t%& is also present &-- see below). Each
168e428f
PH
2778argument can be a comma-separated list of RFC 2822 addresses. This is the
2779default option for selecting the overall action of an Exim call; it is assumed
2780if no other conflicting option is present.
9b371988 2781
168e428f 2782If any addresses in the message are unqualified (have no domain), they are
9b371988
PH
2783qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
2784options, as appropriate. The &%-bnq%& option (see below) provides a way of
168e428f 2785suppressing this for special cases.
9b371988 2786
168e428f 2787Policy checks on the contents of local messages can be enforced by means of
9b371988
PH
2788the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
2789
2790.cindex "return code" "for &%-bm%&"
2791The return code is zero if the message is successfully accepted. Otherwise, the
2792action is controlled by the &%-oe%&&'x'& option setting &-- see below.
2793
168e428f 2794The format
9b371988
PH
2795.cindex "message" "format"
2796.cindex "format" "message"
2797.cindex "&""From""& line"
2798.cindex "UUCP" "&""From""& line"
2799.cindex "Sendmail compatibility" "&""From""& line"
168e428f
PH
2800of the message must be as defined in RFC 2822, except that, for
2801compatibility with Sendmail and Smail, a line in one of the forms
9b371988
PH
2802.code
2803From sender Fri Jan 5 12:55 GMT 1997
2804From sender Fri, 5 Jan 97 12:55:01
2805.endd
168e428f
PH
2806(with the weekday optional, and possibly with additional text after the date)
2807is permitted to appear at the start of the message. There appears to be no
2808authoritative specification of the format of this line. Exim recognizes it by
9b371988 2809matching against the regular expression defined by the &%uucp_from_pattern%&
168e428f 2810option, which can be changed if necessary.
9b371988 2811
168e428f 2812The
9b371988 2813.cindex "&%-f%& option" "overriding &""From""& line"
168e428f 2814specified sender is treated as if it were given as the argument to the
9b371988 2815&%-f%& option, but if a &%-f%& option is also present, its argument is used in
168e428f
PH
2816preference to the address taken from the message. The caller of Exim must be a
2817trusted user for the sender of a message to be set in this way.
2818
9b371988
PH
2819.vitem &%-bnq%&
2820.oindex "&%-bnq%&"
2821.cindex "address qualification" "suppressing"
168e428f
PH
2822By default, Exim automatically qualifies unqualified addresses (those
2823without domains) that appear in messages that are submitted locally (that
2824is, not over TCP/IP). This qualification applies both to addresses in
2825envelopes, and addresses in header lines. Sender addresses are qualified using
9b371988
PH
2826&%qualify_domain%&, and recipient addresses using &%qualify_recipient%& (which
2827defaults to the value of &%qualify_domain%&).
2828
2829Sometimes, qualification is not wanted. For example, if &%-bS%& (batch SMTP) is
168e428f
PH
2830being used to re-submit messages that originally came from remote hosts after
2831content scanning, you probably do not want to qualify unqualified addresses in
2832header lines. (Such lines will be present only if you have not enabled a header
2833syntax check in the appropriate ACL.)
9b371988
PH
2834
2835The &%-bnq%& option suppresses all qualification of unqualified addresses in
168e428f
PH
2836messages that originate on the local host. When this is used, unqualified
2837addresses in the envelope provoke errors (causing message rejection) and
2838unqualified addresses in header lines are left alone.
2839
2840
9b371988
PH
2841.vitem &%-bP%&
2842.oindex "&%-bP%&"
2843.cindex "configuration options" "extracting"
2844.cindex "options" "configuration &-- extracting"
168e428f
PH
2845If this option is given with no arguments, it causes the values of all Exim's
2846main configuration options to be written to the standard output. The values
2847of one or more specific options can be requested by giving their names as
2848arguments, for example:
9b371988
PH
2849.code
2850exim -bP qualify_domain hold_domains
2851.endd
2852However, any option setting that is preceded by the word &"hide"& in the
168e428f
PH
2853configuration file is not shown in full, except to an admin user. For other
2854users, the output is as in this example:
9b371988
PH
2855.code
2856mysql_servers = <value not displayable>
2857.endd
2858If &%configure_file%& is given as an argument, the name of the run time
168e428f
PH
2859configuration file is output.
2860If a list of configuration files was supplied, the value that is output here
2861is the name of the file that was actually used.
168e428f 2862
9b371988
PH
2863.cindex "daemon" "process id (pid)"
2864.cindex "pid (process id)" "of daemon"
2865If &%log_file_path%& or &%pid_file_path%& are given, the names of the
2866directories where log files and daemon pid files are written are output,
2867respectively. If these values are unset, log files are written in a
2868sub-directory of the spool directory called &%log%&, and the pid file is
2869written directly into the spool directory.
2870
2871If &%-bP%& is followed by a name preceded by &`+`&, for example,
2872.code
2873exim -bP +local_domains
2874.endd
168e428f
PH
2875it searches for a matching named list of any type (domain, host, address, or
2876local part) and outputs what it finds.
9b371988
PH
2877
2878.cindex "options" "router &-- extracting"
2879.cindex "options" "transport &-- extracting"
2880If one of the words &%router%&, &%transport%&, or &%authenticator%& is given,
168e428f
PH
2881followed by the name of an appropriate driver instance, the option settings for
2882that driver are output. For example:
9b371988
PH
2883.code
2884exim -bP transport local_delivery
2885.endd
168e428f
PH
2886The generic driver options are output first, followed by the driver's private
2887options. A list of the names of drivers of a particular type can be obtained by
9b371988
PH
2888using one of the words &%router_list%&, &%transport_list%&, or
2889&%authenticator_list%&, and a complete list of all drivers with their option
2890settings can be obtained by using &%routers%&, &%transports%&, or
2891&%authenticators%&.
168e428f
PH
2892
2893
9b371988
PH
2894.vitem &%-bp%&
2895.oindex "&%-bp%&"
2896.cindex "queue" "listing messages on"
2897.cindex "listing" "messages on the queue"
168e428f 2898This option requests a listing of the contents of the mail queue on the
9b371988 2899standard output. If the &%-bp%& option is followed by a list of message ids,
168e428f 2900just those messages are listed. By default, this option can be used only by an
9b371988 2901admin user. However, the &%queue_list_requires_admin%& option can be set false
168e428f 2902to allow any user to see the queue.
168e428f 2903
9b371988
PH
2904Each message on the queue is displayed as in the following example:
2905.code
290625m 2.9K 0t5C6f-0000c8-00 <alice@wonderland.fict.example>
2907 red.king@looking-glass.fict.example
2908 <other addresses>
2909.endd
2910.cindex "message" "size in queue listing"
2911.cindex "size" "of message"
2912The first line contains the length of time the message has been on the queue
168e428f
PH
2913(in this case 25 minutes), the size of the message (2.9K), the unique local
2914identifier for the message, and the message sender, as contained in the
2915envelope. For bounce messages, the sender address is empty, and appears as
9b371988 2916&"<>"&. If the message was submitted locally by an untrusted user who overrode
168e428f
PH
2917the default sender address, the user's login name is shown in parentheses
2918before the sender address.
9b371988
PH
2919
2920.cindex "frozen messages" "in queue listing"
2921If the message is frozen (attempts to deliver it are suspended) then the text
2922&"*** frozen ***"& is displayed at the end of this line.
2923
168e428f
PH
2924The recipients of the message (taken from the envelope, not the headers) are
2925displayed on subsequent lines. Those addresses to which the message has already
2926been delivered are marked with the letter D. If an original address gets
2927expanded into several addresses via an alias or forward file, the original is
2928displayed with a D only when deliveries for all of its child addresses are
2929complete.
2930
2931
9b371988
PH
2932.vitem &%-bpa%&
2933.oindex "&%-bpa%&"
2934This option operates like &%-bp%&, but in addition it shows delivered addresses
168e428f 2935that were generated from the original top level address(es) in each message by
9b371988
PH
2936alias or forwarding operations. These addresses are flagged with &"+D"& instead
2937of just &"D"&.
168e428f
PH
2938
2939
9b371988
PH
2940.vitem &%-bpc%&
2941.oindex "&%-bpc%&"
2942.cindex "queue" "count of messages on"
168e428f
PH
2943This option counts the number of messages on the queue, and writes the total
2944to the standard output. It is restricted to admin users, unless
9b371988 2945&%queue_list_requires_admin%& is set false.
168e428f
PH
2946
2947
9b371988
PH
2948.vitem &%-bpr%&
2949.oindex "&%-bpr%&"
2950This option operates like &%-bp%&, but the output is not sorted into
168e428f
PH
2951chronological order of message arrival. This can speed it up when there are
2952lots of messages on the queue, and is particularly useful if the output is
2953going to be post-processed in a way that doesn't need the sorting.
2954
9b371988
PH
2955.vitem &%-bpra%&
2956.oindex "&%-bpra%&"
2957This option is a combination of &%-bpr%& and &%-bpa%&.
168e428f 2958
9b371988
PH
2959.vitem &%-bpru%&
2960.oindex "&%-bpru%&"
2961This option is a combination of &%-bpr%& and &%-bpu%&.
168e428f
PH
2962
2963
9b371988
PH
2964.vitem &%-bpu%&
2965.oindex "&%-bpu%&"
2966This option operates like &%-bp%& but shows only undelivered top-level
2967addresses for each message displayed. Addresses generated by aliasing or
2968forwarding are not shown, unless the message was deferred after processing by a
2969router with the &%one_time%& option set.
168e428f
PH
2970
2971
9b371988
PH
2972.vitem &%-brt%&
2973.oindex "&%-brt%&"
2974.cindex "testing" "retry configuration"
2975.cindex "retry" "configuration testing"
168e428f
PH
2976This option is for testing retry rules, and it must be followed by up to three
2977arguments. It causes Exim to look for a retry rule that matches the values
2978and to write it to the standard output. For example:
9b371988
PH
2979.code
2980exim -brt bach.comp.mus.example
2981Retry rule: *.comp.mus.example F,2h,15m; F,4d,30m;
2982.endd
4f578862 2983.new
9b371988 2984See chapter &<<CHAPretry>>& for a description of Exim's retry rules. The first
168e428f 2985argument, which is required, can be a complete address in the form
4f578862
PH
2986&'local_part@domain'&, or it can be just a domain name. If the second argument
2987contains a dot, it is interpreted as an optional second domain name; if no
2988retry rule is found for the first argument, the second is tried. This ties in
2989with Exim's behaviour when looking for retry rules for remote hosts &-- if no
2990rule is found that matches the host, one that matches the mail domain is
2991sought. Finally, an argument that is the name of a specific delivery error, as
2992used in setting up retry rules, can be given. For example:
2993.code
2994exim -brt haydn.comp.mus.example quota_3d
2995Retry rule: *@haydn.comp.mus.example quota_3d F,1h,15m
2996.endd
2997.wen
168e428f 2998
9b371988
PH
2999.vitem &%-brw%&
3000.oindex "&%-brw%&"
3001.cindex "testing" "rewriting"
3002.cindex "rewriting" "testing"
168e428f
PH
3003This option is for testing address rewriting rules, and it must be followed by
3004a single argument, consisting of either a local part without a domain, or a
3005complete address with a fully qualified domain. Exim outputs how this address
3006would be rewritten for each possible place it might appear. See chapter
9b371988 3007&<<CHAPrewrite>>& for further details.
168e428f 3008
9b371988
PH
3009.vitem &%-bS%&
3010.oindex "&%-bS%&"
3011.cindex "SMTP" "batched incoming"
3012.cindex "batched SMTP input"
168e428f
PH
3013This option is used for batched SMTP input, which is an alternative interface
3014for non-interactive local message submission. A number of messages can be
3015submitted in a single run. However, despite its name, this is not really SMTP
3016input. Exim reads each message's envelope from SMTP commands on the standard
3017input, but generates no responses. If the caller is trusted, or
9b371988 3018&%untrusted_set_sender%& is set, the senders in the SMTP MAIL commands are
168e428f 3019believed; otherwise the sender is always the caller of Exim.
9b371988 3020
168e428f
PH
3021The message itself is read from the standard input, in SMTP format (leading
3022dots doubled), terminated by a line containing just a single dot. An error is
3023provoked if the terminating dot is missing. A further message may then follow.
9b371988 3024
168e428f 3025As for other local message submissions, the contents of incoming batch SMTP
9b371988
PH
3026messages can be checked using the non-SMTP ACL (see chapter &<<CHAPACL>>&).
3027Unqualified addresses are automatically qualified using &%qualify_domain%& and
3028&%qualify_recipient%&, as appropriate, unless the &%-bnq%& option is used.
3029
168e428f
PH
3030Some other SMTP commands are recognized in the input. HELO and EHLO act
3031as RSET; VRFY, EXPN, ETRN, and HELP act as NOOP;
3032QUIT quits, ignoring the rest of the standard input.
9b371988
PH
3033
3034.cindex "return code" "for &%-bS%&"
168e428f
PH
3035If any error is encountered, reports are written to the standard output and
3036error streams, and Exim gives up immediately. The return code is 0 if no error
3037was detected; it is 1 if one or more messages were accepted before the error
3038was detected; otherwise it is 2.
9b371988 3039
168e428f 3040More details of input using batched SMTP are given in section
9b371988 3041&<<SECTincomingbatchedSMTP>>&.
168e428f 3042
9b371988
PH
3043.vitem &%-bs%&
3044.oindex "&%-bs%&"
3045.cindex "SMTP" "local input"
3046.cindex "local SMTP input"
168e428f
PH
3047This option causes Exim to accept one or more messages by reading SMTP commands
3048on the standard input, and producing SMTP replies on the standard output. SMTP
9b371988 3049policy controls, as defined in ACLs (see chapter &<<CHAPACL>>&) are applied.
168e428f
PH
3050Some user agents use this interface as a way of passing locally-generated
3051messages to the MTA.
9b371988 3052
168e428f 3053In
9b371988
PH
3054.cindex "sender" "source of"
3055this usage, if the caller of Exim is trusted, or &%untrusted_set_sender%& is
168e428f
PH
3056set, the senders of messages are taken from the SMTP MAIL commands.
3057Otherwise the content of these commands is ignored and the sender is set up as
3058the calling user. Unqualified addresses are automatically qualified using
9b371988
PH
3059&%qualify_domain%& and &%qualify_recipient%&, as appropriate, unless the
3060&%-bnq%& option is used.
3061
3062.cindex "inetd"
168e428f 3063The
9b371988
PH
3064&%-bs%& option is also used to run Exim from &'inetd'&, as an alternative to
3065using a listening daemon. Exim can distinguish the two cases by checking
3066whether the standard input is a TCP/IP socket. When Exim is called from
3067&'inetd'&, the source of the mail is assumed to be remote, and the comments
3068above concerning senders and qualification do not apply. In this situation,
3069Exim behaves in exactly the same way as it does when receiving a message via
3070the listening daemon.
3071
3072.vitem &%-bt%&
3073.oindex "&%-bt%&"
3074.cindex "testing" "addresses"
3075.cindex "address" "testing"
168e428f
PH
3076This option runs Exim in address testing mode, in which each argument is taken
3077as an address to be tested for deliverability. The results are written to the
3078standard output. If a test fails, and the caller is not an admin user, no
3079details of the failure are output, because these might contain sensitive
3080information such as usernames and passwords for database lookups.
9b371988 3081
168e428f
PH
3082If no arguments are given, Exim runs in an interactive manner, prompting with a
3083right angle bracket for addresses to be tested.
9b371988
PH
3084
3085Unlike the &%-be%& test option, you cannot arrange for Exim to use the
3086&[readline()]& function, because it is running as &'root'& and there are
168e428f 3087security issues.
9b371988 3088
168e428f 3089Each address is handled as if it were the recipient address of a message
9b371988 3090(compare the &%-bv%& option). It is passed to the routers and the result is
168e428f 3091written to the standard output. However, any router that has
9b371988 3092&%no_address_test%& set is bypassed. This can make &%-bt%& easier to use for
168e428f
PH
3093genuine routing tests if your first router passes everything to a scanner
3094program.
9b371988 3095
168e428f 3096The
9b371988 3097.cindex "return code" "for &%-bt%&"
168e428f
PH
3098return code is 2 if any address failed outright; it is 1 if no address
3099failed outright but at least one could not be resolved for some reason. Return
3100code 0 is given only when all addresses succeed.
9b371988
PH
3101
3102&*Warning*&: &%-bt%& can only do relatively simple testing. If any of the
168e428f
PH
3103routers in the configuration makes any tests on the sender address of a
3104message,
9b371988
PH
3105.cindex "&%-f%& option" "for address testing"
3106you can use the &%-f%& option to set an appropriate sender when running
3107&%-bt%& tests. Without it, the sender is assumed to be the calling user at the
168e428f
PH
3108default qualifying domain. However, if you have set up (for example) routers
3109whose behaviour depends on the contents of an incoming message, you cannot test
9b371988 3110those conditions using &%-bt%&. The &%-N%& option provides a possible way of
168e428f
PH
3111doing such tests.
3112
9b371988
PH
3113.vitem &%-bV%&
3114.oindex "&%-bV%&"
3115.cindex "version number of Exim" "verifying"