Logging: mark continued-TLS connection deliveries with "X-*"
[exim.git] / doc / doc-docbook / spec.xfpt
CommitLineData
9b371988
PH
1. /////////////////////////////////////////////////////////////////////////////
2. This is the primary source of the Exim Manual. It is an xfpt document that is
3. converted into DocBook XML for subsequent conversion into printing and online
4. formats. The markup used herein is "standard" xfpt markup, with some extras.
5. The markup is summarized in a file called Markup.txt.
595028e4
PH
6.
7. WARNING: When you use the .new macro, make sure it appears *before* any
8. adjacent index items; otherwise you get an empty "paragraph" which causes
9. unwanted vertical space.
9b371988
PH
10. /////////////////////////////////////////////////////////////////////////////
11
12.include stdflags
13.include stdmacs
9b371988
PH
14
15. /////////////////////////////////////////////////////////////////////////////
33393583 16. This outputs the standard DocBook boilerplate.
9b371988
PH
17. /////////////////////////////////////////////////////////////////////////////
18
33393583 19.docbook
3cb1b51e
PH
20
21. /////////////////////////////////////////////////////////////////////////////
22. These lines are processing instructions for the Simple DocBook Processor that
f89d2485
PH
23. Philip Hazel has developed as a less cumbersome way of making PostScript and
24. PDFs than using xmlto and fop. They will be ignored by all other XML
25. processors.
3cb1b51e
PH
26. /////////////////////////////////////////////////////////////////////////////
27
28.literal xml
29<?sdop
f89d2485
PH
30 foot_right_recto="&chaptertitle; (&chapternumber;)"
31 foot_right_verso="&chaptertitle; (&chapternumber;)"
3cb1b51e 32 toc_chapter_blanks="yes,yes"
595028e4 33 table_warn_overflow="overprint"
3cb1b51e
PH
34?>
35.literal off
9b371988 36
33393583
PH
37. /////////////////////////////////////////////////////////////////////////////
38. This generate the outermost <book> element that wraps then entire document.
39. /////////////////////////////////////////////////////////////////////////////
40
41.book
42
43. /////////////////////////////////////////////////////////////////////////////
2aee48d6 44. These definitions set some parameters and save some typing.
7d837ca7 45. Update the Copyright year (only) when changing content.
33393583
PH
46. /////////////////////////////////////////////////////////////////////////////
47
54fda09b 48.set previousversion "4.89"
2aee48d6 49.include ./local_params
f89d2485 50
33393583 51.set ACL "access control lists (ACLs)"
f89d2485 52.set I "&nbsp;&nbsp;&nbsp;&nbsp;"
33393583 53
7d837ca7 54.macro copyyear
d4e5e70b 552017
7d837ca7 56.endmacro
9b371988
PH
57
58. /////////////////////////////////////////////////////////////////////////////
59. Additional xfpt markup used by this document, over and above the default
60. provided in the xfpt library.
61. /////////////////////////////////////////////////////////////////////////////
62
63. --- Override the &$ flag to automatically insert a $ with the variable name
64
65.flag &$ $& "<varname>$" "</varname>"
66
67. --- Short flags for daggers in option headings. They will always be inside
68. --- an italic string, but we want the daggers to be roman.
69
70.flag &!! "</emphasis>&dagger;<emphasis>"
71.flag &!? "</emphasis>&Dagger;<emphasis>"
72
73. --- A macro for an Exim option definition heading, generating a one-line
0a4e3112
PH
74. --- table with four columns. For cases when the option name is given with
75. --- a space, so that it can be split, a fifth argument is used for the
76. --- index entry.
9b371988
PH
77
78.macro option
0a4e3112
PH
79.arg 5
80.oindex "&%$5%&"
81.endarg
82.arg -5
3cb1b51e 83.oindex "&%$1%&"
0a4e3112 84.endarg
f89d2485 85.itable all 0 0 4 8* left 6* center 6* center 6* right
9b371988
PH
86.row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&"
87.endtable
88.endmacro
89
90. --- A macro for the common 2-column tables. The width of the first column
91. --- is suitable for the many tables at the start of the main options chapter;
92. --- the small number of other 2-column tables override it.
93
db9452a9 94.macro table2 196pt 254pt
9b371988
PH
95.itable none 0 0 2 $1 left $2 left
96.endmacro
97
f89d2485
PH
98. --- A macro that generates .row, but puts &I; at the start of the first
99. --- argument, thus indenting it. Assume a minimum of two arguments, and
100. --- allow up to four arguments, which is as many as we'll ever need.
101
102.macro irow
103.arg 4
104.row "&I;$1" "$2" "$3" "$4"
105.endarg
106.arg -4
107.arg 3
108.row "&I;$1" "$2" "$3"
109.endarg
110.arg -3
111.row "&I;$1" "$2"
112.endarg
113.endarg
114.endmacro
115
116. --- Macros for option, variable, and concept index entries. For a "range"
117. --- style of entry, use .scindex for the start and .ecindex for the end. The
118. --- first argument of .scindex and the only argument of .ecindex must be the
119. --- ID that ties them together.
9b371988
PH
120
121.macro cindex
122&<indexterm role="concept">&
123&<primary>&$1&</primary>&
124.arg 2
125&<secondary>&$2&</secondary>&
126.endarg
127&</indexterm>&
128.endmacro
129
4f578862
PH
130.macro scindex
131&<indexterm role="concept" id="$1" class="startofrange">&
132&<primary>&$2&</primary>&
133.arg 3
134&<secondary>&$3&</secondary>&
135.endarg
136&</indexterm>&
137.endmacro
138
139.macro ecindex
140&<indexterm role="concept" startref="$1" class="endofrange"/>&
141.endmacro
142
9b371988
PH
143.macro oindex
144&<indexterm role="option">&
145&<primary>&$1&</primary>&
146.arg 2
147&<secondary>&$2&</secondary>&
148.endarg
149&</indexterm>&
150.endmacro
151
f89d2485
PH
152.macro vindex
153&<indexterm role="variable">&
154&<primary>&$1&</primary>&
155.arg 2
156&<secondary>&$2&</secondary>&
157.endarg
158&</indexterm>&
159.endmacro
160
9b371988 161.macro index
f89d2485 162.echo "** Don't use .index; use .cindex or .oindex or .vindex"
9b371988
PH
163.endmacro
164. ////////////////////////////////////////////////////////////////////////////
165
166
167. ////////////////////////////////////////////////////////////////////////////
168. The <bookinfo> element is removed from the XML before processing for Ascii
169. output formats.
170. ////////////////////////////////////////////////////////////////////////////
171
172.literal xml
173<bookinfo>
174<title>Specification of the Exim Mail Transfer Agent</title>
175<titleabbrev>The Exim MTA</titleabbrev>
2aee48d6
JH
176<date>
177.fulldate
178</date>
7b4c60eb
NM
179<author><firstname>Exim</firstname><surname>Maintainers</surname></author>
180<authorinitials>EM</authorinitials>
9b371988 181<revhistory><revision>
99474a17 182.versiondatexml
7b4c60eb 183 <authorinitials>EM</authorinitials>
9b371988 184</revision></revhistory>
2aee48d6 185<copyright><year>
29343b08 186.copyyear
2aee48d6 187 </year><holder>University of Cambridge</holder></copyright>
9b371988
PH
188</bookinfo>
189.literal off
190
191
192. /////////////////////////////////////////////////////////////////////////////
193. This chunk of literal XML implements index entries of the form "x, see y" and
194. "x, see also y". However, the DocBook DTD doesn't allow <indexterm> entries
195. at the top level, so we have to put the .chapter directive first.
196. /////////////////////////////////////////////////////////////////////////////
197
f89d2485 198.chapter "Introduction" "CHID1"
9b371988
PH
199.literal xml
200
f89d2485 201<indexterm role="variable">
168e428f
PH
202 <primary>$1, $2, etc.</primary>
203 <see><emphasis>numerical variables</emphasis></see>
204</indexterm>
205<indexterm role="concept">
206 <primary>address</primary>
207 <secondary>rewriting</secondary>
208 <see><emphasis>rewriting</emphasis></see>
209</indexterm>
210<indexterm role="concept">
068aaea8
PH
211 <primary>Bounce Address Tag Validation</primary>
212 <see><emphasis>BATV</emphasis></see>
213</indexterm>
214<indexterm role="concept">
215 <primary>Client SMTP Authorization</primary>
216 <see><emphasis>CSA</emphasis></see>
217</indexterm>
218<indexterm role="concept">
168e428f
PH
219 <primary>CR character</primary>
220 <see><emphasis>carriage return</emphasis></see>
221</indexterm>
222<indexterm role="concept">
223 <primary>CRL</primary>
224 <see><emphasis>certificate revocation list</emphasis></see>
225</indexterm>
226<indexterm role="concept">
227 <primary>delivery</primary>
228 <secondary>failure report</secondary>
229 <see><emphasis>bounce message</emphasis></see>
230</indexterm>
231<indexterm role="concept">
232 <primary>dialup</primary>
233 <see><emphasis>intermittently connected hosts</emphasis></see>
234</indexterm>
235<indexterm role="concept">
236 <primary>exiscan</primary>
237 <see><emphasis>content scanning</emphasis></see>
238</indexterm>
239<indexterm role="concept">
240 <primary>failover</primary>
241 <see><emphasis>fallback</emphasis></see>
242</indexterm>
243<indexterm role="concept">
244 <primary>fallover</primary>
245 <see><emphasis>fallback</emphasis></see>
246</indexterm>
247<indexterm role="concept">
248 <primary>filter</primary>
249 <secondary>Sieve</secondary>
250 <see><emphasis>Sieve filter</emphasis></see>
251</indexterm>
252<indexterm role="concept">
253 <primary>ident</primary>
254 <see><emphasis>RFC 1413</emphasis></see>
255</indexterm>
256<indexterm role="concept">
257 <primary>LF character</primary>
258 <see><emphasis>linefeed</emphasis></see>
259</indexterm>
260<indexterm role="concept">
261 <primary>maximum</primary>
595028e4 262 <seealso><emphasis>limit</emphasis></seealso>
168e428f
PH
263</indexterm>
264<indexterm role="concept">
068aaea8
PH
265 <primary>monitor</primary>
266 <see><emphasis>Exim monitor</emphasis></see>
267</indexterm>
268<indexterm role="concept">
168e428f
PH
269 <primary>no_<emphasis>xxx</emphasis></primary>
270 <see>entry for xxx</see>
271</indexterm>
272<indexterm role="concept">
273 <primary>NUL</primary>
274 <see><emphasis>binary zero</emphasis></see>
275</indexterm>
276<indexterm role="concept">
277 <primary>passwd file</primary>
278 <see><emphasis>/etc/passwd</emphasis></see>
279</indexterm>
280<indexterm role="concept">
281 <primary>process id</primary>
282 <see><emphasis>pid</emphasis></see>
283</indexterm>
284<indexterm role="concept">
285 <primary>RBL</primary>
286 <see><emphasis>DNS list</emphasis></see>
287</indexterm>
288<indexterm role="concept">
289 <primary>redirection</primary>
290 <see><emphasis>address redirection</emphasis></see>
291</indexterm>
292<indexterm role="concept">
293 <primary>return path</primary>
294 <seealso><emphasis>envelope sender</emphasis></seealso>
295</indexterm>
296<indexterm role="concept">
297 <primary>scanning</primary>
298 <see><emphasis>content scanning</emphasis></see>
299</indexterm>
300<indexterm role="concept">
301 <primary>SSL</primary>
302 <see><emphasis>TLS</emphasis></see>
303</indexterm>
304<indexterm role="concept">
305 <primary>string</primary>
306 <secondary>expansion</secondary>
307 <see><emphasis>expansion</emphasis></see>
308</indexterm>
309<indexterm role="concept">
310 <primary>top bit</primary>
311 <see><emphasis>8-bit characters</emphasis></see>
312</indexterm>
313<indexterm role="concept">
314 <primary>variables</primary>
315 <see><emphasis>expansion, variables</emphasis></see>
316</indexterm>
317<indexterm role="concept">
318 <primary>zero, binary</primary>
319 <see><emphasis>binary zero</emphasis></see>
320</indexterm>
9b371988
PH
321
322.literal off
168e428f
PH
323
324
9b371988
PH
325. /////////////////////////////////////////////////////////////////////////////
326. This is the real start of the first chapter. See the comment above as to why
327. we can't have the .chapter line here.
328. chapter "Introduction"
329. /////////////////////////////////////////////////////////////////////////////
168e428f
PH
330
331Exim is a mail transfer agent (MTA) for hosts that are running Unix or
332Unix-like operating systems. It was designed on the assumption that it would be
333run on hosts that are permanently connected to the Internet. However, it can be
334used on intermittently connected hosts with suitable configuration adjustments.
335
336Configuration files currently exist for the following operating systems: AIX,
068aaea8
PH
337BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, Dragonfly, FreeBSD, GNU/Hurd,
338GNU/Linux, HI-OSF (Hitachi), HI-UX, HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD,
339OpenUNIX, QNX, SCO, SCO SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4,
340Tru64-Unix (formerly Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware.
341Some of these operating systems are no longer current and cannot easily be
342tested, so the configuration files may no longer work in practice.
168e428f
PH
343
344There are also configuration files for compiling Exim in the Cygwin environment
345that can be installed on systems running Windows. However, this document does
346not contain any information about running Exim in the Cygwin environment.
347
348The terms and conditions for the use and distribution of Exim are contained in
9b371988
PH
349the file &_NOTICE_&. Exim is distributed under the terms of the GNU General
350Public Licence, a copy of which may be found in the file &_LICENCE_&.
168e428f
PH
351
352The use, supply or promotion of Exim for the purpose of sending bulk,
353unsolicited electronic mail is incompatible with the basic aims of the program,
354which revolve around the free provision of a service that enhances the quality
355of personal communications. The author of Exim regards indiscriminate
356mass-mailing as an antisocial, irresponsible abuse of the Internet.
357
358Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
359experience of running and working on the Smail 3 code, I could never have
360contemplated starting to write a new MTA. Many of the ideas and user interfaces
361were originally taken from Smail 3, though the actual code of Exim is entirely
362new, and has developed far beyond the initial concept.
363
364Many people, both in Cambridge and around the world, have contributed to the
365development and the testing of Exim, and to porting it to various operating
366systems. I am grateful to them all. The distribution now contains a file called
9b371988 367&_ACKNOWLEDGMENTS_&, in which I have started recording the names of
168e428f
PH
368contributors.
369
370
f89d2485 371.section "Exim documentation" "SECID1"
800d5176 372. Keep this example change bar when updating the documentation!
b52ed2b3 373
54fda09b 374.new
9b371988 375.cindex "documentation"
2aee48d6 376This edition of the Exim specification applies to version &version() of Exim.
9b371988 377Substantive changes from the &previousversion; edition are marked in some
168e428f
PH
378renditions of the document; this paragraph is so marked if the rendition is
379capable of showing a change indicator.
54fda09b 380.wen
168e428f
PH
381
382This document is very much a reference manual; it is not a tutorial. The reader
383is expected to have some familiarity with the SMTP mail transfer protocol and
384with general Unix system administration. Although there are some discussions
385and examples in places, the information is mostly organized in a way that makes
386it easy to look up, rather than in a natural order for sequential reading.
387Furthermore, the manual aims to cover every aspect of Exim in detail, including
388a number of rarely-used, special-purpose features that are unlikely to be of
389very wide interest.
390
9b371988
PH
391.cindex "books about Exim"
392An &"easier"& discussion of Exim which provides more in-depth explanatory,
393introductory, and tutorial material can be found in a book entitled &'The Exim
595028e4 394SMTP Mail Server'& (second edition, 2007), published by UIT Cambridge
9b371988 395(&url(http://www.uit.co.uk/exim-book/)).
168e428f
PH
396
397This book also contains a chapter that gives a general introduction to SMTP and
398Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
399with the latest release of Exim. (Note that the earlier book about Exim,
400published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
401
9b371988 402.cindex "Debian" "information sources"
068aaea8
PH
403If you are using a Debian distribution of Exim, you will find information about
404Debian-specific features in the file
f89d2485 405&_/usr/share/doc/exim4-base/README.Debian_&.
9b371988 406The command &(man update-exim.conf)& is another source of Debian-specific
068aaea8
PH
407information.
408
9b371988
PH
409.cindex "&_doc/NewStuff_&"
410.cindex "&_doc/ChangeLog_&"
411.cindex "change log"
168e428f
PH
412As the program develops, there may be features in newer versions that have not
413yet made it into this document, which is updated only when the most significant
414digit of the fractional part of the version number changes. Specifications of
415new features that are not yet in this manual are placed in the file
9b371988 416&_doc/NewStuff_& in the Exim distribution.
168e428f 417
9b371988 418Some features may be classified as &"experimental"&. These may change
168e428f
PH
419incompatibly while they are developing, or even be withdrawn. For this reason,
420they are not documented in this manual. Information about experimental features
9b371988 421can be found in the file &_doc/experimental.txt_&.
168e428f
PH
422
423All changes to the program (whether new features, bug fixes, or other kinds of
9b371988 424change) are noted briefly in the file called &_doc/ChangeLog_&.
168e428f 425
9b371988
PH
426.cindex "&_doc/spec.txt_&"
427This specification itself is available as an ASCII file in &_doc/spec.txt_& so
428that it can easily be searched with a text editor. Other files in the &_doc_&
168e428f
PH
429directory are:
430
9b371988
PH
431.table2 100pt
432.row &_OptionLists.txt_& "list of all options in alphabetical order"
433.row &_dbm.discuss.txt_& "discussion about DBM libraries"
434.row &_exim.8_& "a man page of Exim's command line options"
435.row &_experimental.txt_& "documentation of experimental features"
436.row &_filter.txt_& "specification of the filter language"
9b371988
PH
437.row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
438.row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
2eec84ca 439.row &_openssl.txt_& "installing a current OpenSSL release"
9b371988 440.endtable
168e428f
PH
441
442The main specification and the specification of the filtering language are also
443available in other formats (HTML, PostScript, PDF, and Texinfo). Section
9b371988 444&<<SECTavail>>& below tells you how to get hold of these.
168e428f
PH
445
446
447
f89d2485 448.section "FTP and web sites" "SECID2"
9b371988
PH
449.cindex "web site"
450.cindex "FTP site"
068aaea8 451The primary site for Exim source distributions is currently the University of
9b371988
PH
452Cambridge's FTP site, whose contents are described in &'Where to find the Exim
453distribution'& below. In addition, there is a web site and an FTP site at
454&%exim.org%&. These are now also hosted at the University of Cambridge. The
455&%exim.org%& site was previously hosted for a number of years by Energis
456Squared, formerly Planet Online Ltd, whose support I gratefully acknowledge.
457
458.cindex "wiki"
459.cindex "FAQ"
168e428f 460As well as Exim distribution tar files, the Exim web site contains a number of
f89d2485 461differently formatted versions of the documentation. A recent addition to the
7d0ab55c 462online information is the Exim wiki (&url(http://wiki.exim.org)),
f89d2485
PH
463which contains what used to be a separate FAQ, as well as various other
464examples, tips, and know-how that have been contributed by Exim users.
465
466.cindex Bugzilla
7d0ab55c 467An Exim Bugzilla exists at &url(http://bugs.exim.org). You can use
f89d2485
PH
468this to report bugs, and also to add items to the wish list. Please search
469first to check that you are not duplicating a previous entry.
168e428f
PH
470
471
472
f89d2485 473.section "Mailing lists" "SECID3"
9b371988 474.cindex "mailing lists" "for Exim users"
f89d2485 475The following Exim mailing lists exist:
168e428f 476
9b371988 477.table2 140pt
d854d3a9 478.row &'exim-announce@exim.org'& "Moderated, low volume announcements list"
f89d2485
PH
479.row &'exim-users@exim.org'& "General discussion list"
480.row &'exim-dev@exim.org'& "Discussion of bugs, enhancements, etc."
d854d3a9 481.row &'exim-cvs@exim.org'& "Automated commit messages from the VCS"
9b371988 482.endtable
168e428f
PH
483
484You can subscribe to these lists, change your existing subscriptions, and view
9b371988
PH
485or search the archives via the mailing lists link on the Exim home page.
486.cindex "Debian" "mailing list for"
4f578862 487If you are using a Debian distribution of Exim, you may wish to subscribe to
db9452a9
PH
488the Debian-specific mailing list &'pkg-exim4-users@lists.alioth.debian.org'&
489via this web page:
490.display
491&url(http://lists.alioth.debian.org/mailman/listinfo/pkg-exim4-users)
492.endd
493Please ask Debian-specific questions on this list and not on the general Exim
494lists.
9b371988 495
f89d2485 496.section "Exim training" "SECID4"
9b371988 497.cindex "training courses"
595028e4
PH
498Training courses in Cambridge (UK) used to be run annually by the author of
499Exim, before he retired. At the time of writing, there are no plans to run
500further Exim courses in Cambridge. However, if that changes, relevant
501information will be posted at &url(http://www-tus.csx.cam.ac.uk/courses/exim/).
168e428f 502
f89d2485 503.section "Bug reports" "SECID5"
9b371988
PH
504.cindex "bug reports"
505.cindex "reporting bugs"
7d0ab55c
TF
506Reports of obvious bugs can be emailed to &'bugs@exim.org'& or reported
507via the Bugzilla (&url(http://bugs.exim.org)). However, if you are unsure
595028e4
PH
508whether some behaviour is a bug or not, the best thing to do is to post a
509message to the &'exim-dev'& mailing list and have it discussed.
168e428f
PH
510
511
512
9b371988
PH
513.section "Where to find the Exim distribution" "SECTavail"
514.cindex "FTP site"
515.cindex "distribution" "ftp site"
168e428f 516The master ftp site for the Exim distribution is
9b371988
PH
517.display
518&*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim*&
519.endd
168e428f 520This is mirrored by
9b371988
PH
521.display
522&*ftp://ftp.exim.org/pub/exim*&
523.endd
524The file references that follow are relative to the &_exim_& directories at
525these sites. There are now quite a number of independent mirror sites around
526the world. Those that I know about are listed in the file called &_Mirrors_&.
527
528Within the &_exim_& directory there are subdirectories called &_exim3_& (for
529previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
530distributions), and &_Testing_& for testing versions. In the &_exim4_&
168e428f 531subdirectory, the current release can always be found in files called
9b371988
PH
532.display
533&_exim-n.nn.tar.gz_&
534&_exim-n.nn.tar.bz2_&
535.endd
536where &'n.nn'& is the highest such version number in the directory. The two
168e428f 537files contain identical data; the only difference is the type of compression.
9b371988 538The &_.bz2_& file is usually a lot smaller than the &_.gz_& file.
168e428f 539
9b371988
PH
540.cindex "distribution" "signing details"
541.cindex "distribution" "public key"
542.cindex "public key for signed distribution"
40167b05
PP
543The distributions will be PGP signed by an individual key of the Release
544Coordinator. This key will have a uid containing an email address in the
545&'exim.org'& domain and will have signatures from other people, including
546other Exim maintainers. We expect that the key will be in the "strong set" of
547PGP keys. There should be a trust path to that key from Nigel Metheringham's
548PGP key, a version of which can be found in the release directory in the file
549&_nigel-pubkey.asc_&. All keys used will be available in public keyserver pools,
550such as &'pool.sks-keyservers.net'&.
551
552At time of last update, releases were being made by Phil Pennock and signed with
553key &'0x403043153903637F'&, although that key is expected to be replaced in 2013.
554A trust path from Nigel's key to Phil's can be observed at
555&url(https://www.security.spodhuis.org/exim-trustpath).
85b2d6f3 556
85b2d6f3
TL
557Releases have also been authorized to be performed by Todd Lyons who signs with
558key &'0xC4F4F94804D29EBA'&. A direct trust path exists between previous RE Phil
559Pennock and Todd Lyons through a common associate.
40167b05
PP
560
561The signatures for the tar bundles are in:
9b371988 562.display
210f147e
NM
563&_exim-n.nn.tar.gz.asc_&
564&_exim-n.nn.tar.bz2.asc_&
9b371988 565.endd
168e428f 566For each released version, the log of changes is made separately available in a
9b371988 567separate file in the directory &_ChangeLogs_& so that it is possible to
168e428f
PH
568find out what has changed without having to download the entire distribution.
569
9b371988 570.cindex "documentation" "available formats"
168e428f
PH
571The main distribution contains ASCII versions of this specification and other
572documentation; other formats of the documents are available in separate files
9b371988
PH
573inside the &_exim4_& directory of the FTP site:
574.display
575&_exim-html-n.nn.tar.gz_&
576&_exim-pdf-n.nn.tar.gz_&
577&_exim-postscript-n.nn.tar.gz_&
578&_exim-texinfo-n.nn.tar.gz_&
579.endd
580These tar files contain only the &_doc_& directory, not the complete
581distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
168e428f 582
168e428f 583
f89d2485 584.section "Limitations" "SECID6"
9b371988
PH
585.ilist
586.cindex "limitations of Exim"
587.cindex "bang paths" "not handled by Exim"
588Exim is designed for use as an Internet MTA, and therefore handles addresses in
589RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
590simple two-component bang paths can be converted by a straightforward rewriting
591configuration. This restriction does not prevent Exim from being interfaced to
592UUCP as a transport mechanism, provided that domain addresses are used.
593.next
594.cindex "domainless addresses"
595.cindex "address" "without domain"
168e428f
PH
596Exim insists that every address it handles has a domain attached. For incoming
597local messages, domainless addresses are automatically qualified with a
598configured domain value. Configuration options specify from which remote
599systems unqualified addresses are acceptable. These are then qualified on
600arrival.
9b371988
PH
601.next
602.cindex "transport" "external"
603.cindex "external transports"
604The only external transport mechanisms that are currently implemented are SMTP
605and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
168e428f 606transport is available, and there are facilities for writing messages to files
9b371988
PH
607and pipes, optionally in &'batched SMTP'& format; these facilities can be used
608to send messages to other transport mechanisms such as UUCP, provided they can
609handle domain-style addresses. Batched SMTP input is also catered for.
610.next
611Exim is not designed for storing mail for dial-in hosts. When the volumes of
612such mail are large, it is better to get the messages &"delivered"& into files
168e428f
PH
613(that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
614other means.
9b371988
PH
615.next
616Although Exim does have basic facilities for scanning incoming messages, these
168e428f
PH
617are not comprehensive enough to do full virus or spam scanning. Such operations
618are best carried out using additional specialized software packages. If you
619compile Exim with the content-scanning extension, straightforward interfaces to
620a number of common scanners are provided.
9b371988 621.endlist
168e428f
PH
622
623
f89d2485 624.section "Run time configuration" "SECID7"
168e428f
PH
625Exim's run time configuration is held in a single text file that is divided
626into a number of sections. The entries in this file consist of keywords and
627values, in the style of Smail 3 configuration files. A default configuration
628file which is suitable for simple online installations is provided in the
9b371988 629distribution, and is described in chapter &<<CHAPdefconfil>>& below.
168e428f
PH
630
631
f89d2485 632.section "Calling interface" "SECID8"
9b371988 633.cindex "Sendmail compatibility" "command line interface"
168e428f 634Like many MTAs, Exim has adopted the Sendmail command line interface so that it
9b371988
PH
635can be a straight replacement for &_/usr/lib/sendmail_& or
636&_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
168e428f
PH
637about Sendmail in order to run Exim. For actions other than sending messages,
638Sendmail-compatible options also exist, but those that produce output (for
9b371988 639example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
168e428f 640format. There are also some additional options that are compatible with Smail
9b371988 6413, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
168e428f
PH
642documents all Exim's command line options. This information is automatically
643made into the man page that forms part of the Exim distribution.
644
645Control of messages on the queue can be done via certain privileged command
9b371988
PH
646line options. There is also an optional monitor program called &'eximon'&,
647which displays current information in an X window, and which contains a menu
168e428f
PH
648interface to Exim's command line administration options.
649
650
651
f89d2485 652.section "Terminology" "SECID9"
9b371988
PH
653.cindex "terminology definitions"
654.cindex "body of message" "definition of"
655The &'body'& of a message is the actual data that the sender wants to transmit.
656It is the last part of a message, and is separated from the &'header'& (see
168e428f
PH
657below) by a blank line.
658
9b371988 659.cindex "bounce message" "definition of"
168e428f 660When a message cannot be delivered, it is normally returned to the sender in a
9b371988
PH
661delivery failure message or a &"non-delivery report"& (NDR). The term
662&'bounce'& is commonly used for this action, and the error reports are often
663called &'bounce messages'&. This is a convenient shorthand for &"delivery
664failure error report"&. Such messages have an empty sender address in the
665message's &'envelope'& (see below) to ensure that they cannot themselves give
666rise to further bounce messages.
667
668The term &'default'& appears frequently in this manual. It is used to qualify a
168e428f
PH
669value which is used in the absence of any setting in the configuration. It may
670also qualify an action which is taken unless a configuration setting specifies
671otherwise.
672
9b371988 673The term &'defer'& is used when the delivery of a message to a specific
168e428f 674destination cannot immediately take place for some reason (a remote host may be
9b371988 675down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
168e428f
PH
676until a later time.
677
9b371988
PH
678The word &'domain'& is sometimes used to mean all but the first component of a
679host's name. It is &'not'& used in that sense here, where it normally refers to
680the part of an email address following the @ sign.
168e428f 681
f89d2485 682.cindex "envelope, definition of"
9b371988
PH
683.cindex "sender" "definition of"
684A message in transit has an associated &'envelope'&, as well as a header and a
168e428f
PH
685body. The envelope contains a sender address (to which bounce messages should
686be delivered), and any number of recipient addresses. References to the
687sender or the recipients of a message usually mean the addresses in the
688envelope. An MTA uses these addresses for delivery, and for returning bounce
689messages, not the addresses that appear in the header lines.
690
f89d2485 691.cindex "message" "header, definition of"
9b371988
PH
692.cindex "header section" "definition of"
693The &'header'& of a message is the first part of a message's text, consisting
694of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
695&'Subject:'&, etc. Long header lines can be split over several text lines by
168e428f
PH
696indenting the continuations. The header is separated from the body by a blank
697line.
698
9b371988
PH
699.cindex "local part" "definition of"
700.cindex "domain" "definition of"
701The term &'local part'&, which is taken from RFC 2822, is used to refer to that
168e428f 702part of an email address that precedes the @ sign. The part that follows the
9b371988 703@ sign is called the &'domain'& or &'mail domain'&.
168e428f 704
9b371988 705.cindex "local delivery" "definition of"
f89d2485 706.cindex "remote delivery, definition of"
9b371988 707The terms &'local delivery'& and &'remote delivery'& are used to distinguish
168e428f 708delivery to a file or a pipe on the local host from delivery by SMTP over
068aaea8 709TCP/IP to another host. As far as Exim is concerned, all hosts other than the
9b371988 710host it is running on are &'remote'&.
168e428f 711
9b371988
PH
712.cindex "return path" "definition of"
713&'Return path'& is another name that is used for the sender address in a
168e428f
PH
714message's envelope.
715
9b371988
PH
716.cindex "queue" "definition of"
717The term &'queue'& is used to refer to the set of messages awaiting delivery,
168e428f
PH
718because this term is in widespread use in the context of MTAs. However, in
719Exim's case the reality is more like a pool than a queue, because there is
720normally no ordering of waiting messages.
721
9b371988
PH
722.cindex "queue runner" "definition of"
723The term &'queue runner'& is used to describe a process that scans the queue
168e428f 724and attempts to deliver those messages whose retry times have come. This term
9b371988 725is used by other MTAs, and also relates to the command &%runq%&, but in Exim
168e428f
PH
726the waiting messages are normally processed in an unpredictable order.
727
9b371988
PH
728.cindex "spool directory" "definition of"
729The term &'spool directory'& is used for a directory in which Exim keeps the
730messages on its queue &-- that is, those that it is in the process of
168e428f 731delivering. This should not be confused with the directory in which local
9b371988
PH
732mailboxes are stored, which is called a &"spool directory"& by some people. In
733the Exim documentation, &"spool"& is always used in the first sense.
168e428f
PH
734
735
736
737
738
739
9b371988
PH
740. ////////////////////////////////////////////////////////////////////////////
741. ////////////////////////////////////////////////////////////////////////////
168e428f 742
f89d2485 743.chapter "Incorporated code" "CHID2"
9b371988
PH
744.cindex "incorporated code"
745.cindex "regular expressions" "library"
746.cindex "PCRE"
1899bab2 747.cindex "OpenDMARC"
168e428f
PH
748A number of pieces of external code are included in the Exim distribution.
749
9b371988 750.ilist
210f147e
NM
751Regular expressions are supported in the main Exim program and in the
752Exim monitor using the freely-distributable PCRE library, copyright
40df1be3
TF
753&copy; University of Cambridge. The source to PCRE is no longer shipped with
754Exim, so you will need to use the version of PCRE shipped with your system,
755or obtain and install the full version of the library from
f89d2485 756&url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
9b371988 757.next
f89d2485 758.cindex "cdb" "acknowledgment"
168e428f
PH
759Support for the cdb (Constant DataBase) lookup method is provided by code
760contributed by Nigel Metheringham of (at the time he contributed it) Planet
9b371988
PH
761Online Ltd. The implementation is completely contained within the code of Exim.
762It does not link against an external cdb library. The code contains the
763following statements:
764
765.blockquote
766Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
767
168e428f
PH
768This program is free software; you can redistribute it and/or modify it under
769the terms of the GNU General Public License as published by the Free Software
770Foundation; either version 2 of the License, or (at your option) any later
771version.
168e428f
PH
772This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
773the spec and sample code for cdb can be obtained from
f89d2485
PH
774&url(http://www.pobox.com/~djb/cdb.html). This implementation borrows
775some code from Dan Bernstein's implementation (which has no license
776restrictions applied to it).
9b371988
PH
777.endblockquote
778.next
779.cindex "SPA authentication"
780.cindex "Samba project"
781.cindex "Microsoft Secure Password Authentication"
782Client support for Microsoft's &'Secure Password Authentication'& is provided
168e428f
PH
783by code contributed by Marc Prud'hommeaux. Server support was contributed by
784Tom Kistner. This includes code taken from the Samba project, which is released
785under the Gnu GPL.
9b371988
PH
786.next
787.cindex "Cyrus"
788.cindex "&'pwcheck'& daemon"
789.cindex "&'pwauthd'& daemon"
790Support for calling the Cyrus &'pwcheck'& and &'saslauthd'& daemons is provided
168e428f
PH
791by code taken from the Cyrus-SASL library and adapted by Alexander S.
792Sabourenkov. The permission notice appears below, in accordance with the
793conditions expressed therein.
9b371988
PH
794
795.blockquote
796Copyright &copy; 2001 Carnegie Mellon University. All rights reserved.
797
168e428f
PH
798Redistribution and use in source and binary forms, with or without
799modification, are permitted provided that the following conditions
800are met:
168e428f 801
9b371988
PH
802.olist
803Redistributions of source code must retain the above copyright
804notice, this list of conditions and the following disclaimer.
805.next
806Redistributions in binary form must reproduce the above copyright
168e428f
PH
807notice, this list of conditions and the following disclaimer in
808the documentation and/or other materials provided with the
809distribution.
9b371988
PH
810.next
811The name &"Carnegie Mellon University"& must not be used to
168e428f
PH
812endorse or promote products derived from this software without
813prior written permission. For permission or any other legal
814details, please contact
9b371988 815.display
068aaea8
PH
816 Office of Technology Transfer
817 Carnegie Mellon University
818 5000 Forbes Avenue
819 Pittsburgh, PA 15213-3890
820 (412) 268-4387, fax: (412) 268-7395
821 tech-transfer@andrew.cmu.edu
9b371988
PH
822.endd
823.next
824Redistributions of any form whatsoever must retain the following
168e428f 825acknowledgment:
9b371988
PH
826
827&"This product includes software developed by Computing Services
828at Carnegie Mellon University (&url(http://www.cmu.edu/computing/)."&
829
168e428f
PH
830CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
831THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
832AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
833FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
834WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
835AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
836OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
9b371988
PH
837.endlist
838.endblockquote
168e428f 839
9b371988 840.next
f89d2485 841.cindex "Exim monitor" "acknowledgment"
9b371988
PH
842.cindex "X-windows"
843.cindex "Athena"
168e428f
PH
844The Exim Monitor program, which is an X-Window application, includes
845modified versions of the Athena StripChart and TextPop widgets.
846This code is copyright by DEC and MIT, and their permission notice appears
847below, in accordance with the conditions expressed therein.
9b371988
PH
848
849.blockquote
168e428f
PH
850Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
851and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
9b371988 852
168e428f 853All Rights Reserved
9b371988 854
168e428f
PH
855Permission to use, copy, modify, and distribute this software and its
856documentation for any purpose and without fee is hereby granted,
857provided that the above copyright notice appear in all copies and that
858both that copyright notice and this permission notice appear in
859supporting documentation, and that the names of Digital or MIT not be
860used in advertising or publicity pertaining to distribution of the
861software without specific, written prior permission.
9b371988 862
168e428f
PH
863DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
864ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
865DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
866ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
867WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
868ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
869SOFTWARE.
9b371988 870.endblockquote
168e428f 871
9b371988 872.next
1899bab2
TL
873.cindex "opendmarc" "acknowledgment"
874The DMARC implementation uses the OpenDMARC library which is Copyrighted by
875The Trusted Domain Project. Portions of Exim source which use OpenDMARC
876derived code are indicated in the respective source files. The full OpenDMARC
877license is provided in the LICENSE.opendmarc file contained in the distributed
878source code.
879
880.next
9b371988 881Many people have contributed code fragments, some large, some small, that were
168e428f 882not covered by any specific licence requirements. It is assumed that the
f89d2485 883contributors are happy to see their code incorporated into Exim under the GPL.
9b371988 884.endlist
168e428f
PH
885
886
887
888
889
9b371988
PH
890. ////////////////////////////////////////////////////////////////////////////
891. ////////////////////////////////////////////////////////////////////////////
168e428f 892
f89d2485 893.chapter "How Exim receives and delivers mail" "CHID11" &&&
9b371988 894 "Receiving and delivering mail"
168e428f
PH
895
896
f89d2485 897.section "Overall philosophy" "SECID10"
9b371988 898.cindex "design philosophy"
168e428f
PH
899Exim is designed to work efficiently on systems that are permanently connected
900to the Internet and are handling a general mix of mail. In such circumstances,
901most messages can be delivered immediately. Consequently, Exim does not
902maintain independent queues of messages for specific domains or hosts, though
903it does try to send several messages in a single SMTP connection after a host
904has been down, and it also maintains per-host retry information.
905
906
f89d2485 907.section "Policy control" "SECID11"
9b371988 908.cindex "policy control" "overview"
168e428f
PH
909Policy controls are now an important feature of MTAs that are connected to the
910Internet. Perhaps their most important job is to stop MTAs being abused as
9b371988
PH
911&"open relays"& by misguided individuals who send out vast amounts of
912unsolicited junk, and want to disguise its source. Exim provides flexible
913facilities for specifying policy controls on incoming mail:
168e428f 914
9b371988
PH
915.ilist
916.cindex "&ACL;" "introduction"
168e428f 917Exim 4 (unlike previous versions of Exim) implements policy controls on
9b371988 918incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
168e428f
PH
919series of statements that may either grant or deny access. ACLs can be used at
920several places in the SMTP dialogue while receiving a message from a remote
9b371988
PH
921host. However, the most common places are after each RCPT command, and at the
922very end of the message. The sysadmin can specify conditions for accepting or
923rejecting individual recipients or the entire message, respectively, at these
924two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
168e428f 925error code.
9b371988
PH
926.next
927An ACL is also available for locally generated, non-SMTP messages. In this
168e428f 928case, the only available actions are to accept or deny the entire message.
9b371988
PH
929.next
930When Exim is compiled with the content-scanning extension, facilities are
168e428f
PH
931provided in the ACL mechanism for passing the message to external virus and/or
932spam scanning software. The result of such a scan is passed back to the ACL,
933which can then use it to decide what to do with the message.
9b371988
PH
934.next
935When a message has been received, either from a remote host or from the local
f89d2485 936host, but before the final acknowledgment has been sent, a locally supplied C
9b371988
PH
937function called &[local_scan()]& can be run to inspect the message and decide
938whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
939is accepted, the list of recipients can be modified by the function.
940.next
941Using the &[local_scan()]& mechanism is another way of calling external scanner
942software. The &%SA-Exim%& add-on package works this way. It does not require
943Exim to be compiled with the content-scanning extension.
944.next
945After a message has been accepted, a further checking mechanism is available in
946the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
947runs at the start of every delivery process.
948.endlist
949
950
951
f89d2485 952.section "User filters" "SECID12"
9b371988
PH
953.cindex "filter" "introduction"
954.cindex "Sieve filter"
168e428f 955In a conventional Exim configuration, users are able to run private filters by
9b371988
PH
956setting up appropriate &_.forward_& files in their home directories. See
957chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
958configuration needed to support this, and the separate document entitled
959&'Exim's interfaces to mail filtering'& for user details. Two different kinds
960of filtering are available:
961
962.ilist
963Sieve filters are written in the standard filtering language that is defined
168e428f 964by RFC 3028.
9b371988
PH
965.next
966Exim filters are written in a syntax that is unique to Exim, but which is more
168e428f 967powerful than Sieve, which it pre-dates.
9b371988 968.endlist
168e428f
PH
969
970User filters are run as part of the routing process, described below.
971
972
973
9b371988
PH
974.section "Message identification" "SECTmessiden"
975.cindex "message ids" "details of format"
976.cindex "format" "of message id"
977.cindex "id of message"
978.cindex "base62"
979.cindex "base36"
980.cindex "Darwin"
981.cindex "Cygwin"
982Every message handled by Exim is given a &'message id'& which is sixteen
168e428f 983characters long. It is divided into three parts, separated by hyphens, for
9b371988 984example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
168e428f
PH
985normally encoding numbers in base 62. However, in the Darwin operating
986system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
987(avoiding the use of lower case letters) is used instead, because the message
988id is used to construct file names, and the names of files in those systems are
068aaea8 989not always case-sensitive.
168e428f 990
9b371988 991.cindex "pid (process id)" "re-use of"
168e428f
PH
992The detail of the contents of the message id have changed as Exim has evolved.
993Earlier versions relied on the operating system not re-using a process id (pid)
994within one second. On modern operating systems, this assumption can no longer
995be made, so the algorithm had to be changed. To retain backward compatibility,
996the format of the message id was retained, which is why the following rules are
997somewhat eccentric:
998
9b371988
PH
999.ilist
1000The first six characters of the message id are the time at which the message
168e428f
PH
1001started to be received, to a granularity of one second. That is, this field
1002contains the number of seconds since the start of the epoch (the normal Unix
1003way of representing the date and time of day).
9b371988
PH
1004.next
1005After the first hyphen, the next six characters are the id of the process that
168e428f 1006received the message.
9b371988
PH
1007.next
1008There are two different possibilities for the final two characters:
1009.olist
0a4e3112 1010.oindex "&%localhost_number%&"
9b371988 1011If &%localhost_number%& is not set, this value is the fractional part of the
168e428f
PH
1012time of reception, normally in units of 1/2000 of a second, but for systems
1013that must use base 36 instead of base 62 (because of case-insensitive file
1014systems), the units are 1/1000 of a second.
9b371988
PH
1015.next
1016If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
168e428f
PH
1017the fractional part of the time, which in this case is in units of 1/200
1018(1/100) of a second.
9b371988
PH
1019.endlist
1020.endlist
168e428f
PH
1021
1022After a message has been received, Exim waits for the clock to tick at the
1023appropriate resolution before proceeding, so that if another message is
1024received by the same process, or by another process with the same (re-used)
1025pid, it is guaranteed that the time will be different. In most cases, the clock
1026will already have ticked while the message was being received.
1027
1028
f89d2485 1029.section "Receiving mail" "SECID13"
9b371988
PH
1030.cindex "receiving mail"
1031.cindex "message" "reception"
068aaea8
PH
1032The only way Exim can receive mail from another host is using SMTP over
1033TCP/IP, in which case the sender and recipient addresses are transferred using
168e428f
PH
1034SMTP commands. However, from a locally running process (such as a user's MUA),
1035there are several possibilities:
1036
9b371988
PH
1037.ilist
1038If the process runs Exim with the &%-bm%& option, the message is read
168e428f 1039non-interactively (usually via a pipe), with the recipients taken from the
9b371988
PH
1040command line, or from the body of the message if &%-t%& is also used.
1041.next
1042If the process runs Exim with the &%-bS%& option, the message is also read
168e428f
PH
1043non-interactively, but in this case the recipients are listed at the start of
1044the message in a series of SMTP RCPT commands, terminated by a DATA
9b371988 1045command. This is so-called &"batch SMTP"& format,
168e428f
PH
1046but it isn't really SMTP. The SMTP commands are just another way of passing
1047envelope addresses in a non-interactive submission.
9b371988
PH
1048.next
1049If the process runs Exim with the &%-bs%& option, the message is read
168e428f
PH
1050interactively, using the SMTP protocol. A two-way pipe is normally used for
1051passing data between the local process and the Exim process.
9b371988 1052This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
168e428f 1053example, the ACLs for SMTP commands are used for this form of submission.
9b371988
PH
1054.next
1055A local process may also make a TCP/IP call to the host's loopback address
168e428f
PH
1056(127.0.0.1) or any other of its IP addresses. When receiving messages, Exim
1057does not treat the loopback address specially. It treats all such connections
1058in the same way as connections from other hosts.
9b371988 1059.endlist
168e428f
PH
1060
1061
f89d2485 1062.cindex "message sender, constructed by Exim"
9b371988 1063.cindex "sender" "constructed by Exim"
168e428f
PH
1064In the three cases that do not involve TCP/IP, the sender address is
1065constructed from the login name of the user that called Exim and a default
9b371988 1066qualification domain (which can be set by the &%qualify_domain%& configuration
168e428f
PH
1067option). For local or batch SMTP, a sender address that is passed using the
1068SMTP MAIL command is ignored. However, the system administrator may allow
9b371988 1069certain users (&"trusted users"&) to specify a different sender address
168e428f 1070unconditionally, or all users to specify certain forms of different sender
9b371988
PH
1071address. The &%-f%& option or the SMTP MAIL command is used to specify these
1072different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1073users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
168e428f
PH
1074users to change sender addresses.
1075
1076Messages received by either of the non-interactive mechanisms are subject to
1077checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1078(either over TCP/IP, or interacting with a local process) can be checked by a
1079number of ACLs that operate at different times during the SMTP session. Either
1080individual recipients, or the entire message, can be rejected if local policy
9b371988
PH
1081requirements are not met. The &[local_scan()]& function (see chapter
1082&<<CHAPlocalscan>>&) is run for all incoming messages.
168e428f
PH
1083
1084Exim can be configured not to start a delivery process when a message is
1085received; this can be unconditional, or depend on the number of incoming SMTP
1086connections or the system load. In these situations, new messages wait on the
1087queue until a queue runner process picks them up. However, in standard
1088configurations under normal conditions, delivery is started as soon as a
1089message is received.
1090
1091
1092
1093
1094
f89d2485 1095.section "Handling an incoming message" "SECID14"
9b371988
PH
1096.cindex "spool directory" "files that hold a message"
1097.cindex "file" "how a message is held"
168e428f
PH
1098When Exim accepts a message, it writes two files in its spool directory. The
1099first contains the envelope information, the current status of the message, and
1100the header lines, and the second contains the body of the message. The names of
9b371988
PH
1101the two spool files consist of the message id, followed by &`-H`& for the
1102file containing the envelope and header, and &`-D`& for the data file.
168e428f 1103
9b371988 1104.cindex "spool directory" "&_input_& sub-directory"
168e428f 1105By default all these message files are held in a single directory called
9b371988 1106&_input_& inside the general Exim spool directory. Some operating systems do
c0712871 1107not perform very well if the number of files in a directory gets large; to
9b371988 1108improve performance in such cases, the &%split_spool_directory%& option can be
168e428f 1109used. This causes Exim to split up the input files into 62 sub-directories
db9452a9 1110whose names are single letters or digits. When this is done, the queue is
c0712871
PH
1111processed one sub-directory at a time instead of all at once, which can improve
1112overall performance even when there are not enough files in each directory to
db9452a9 1113affect file system performance.
168e428f
PH
1114
1115The envelope information consists of the address of the message's sender and
1116the addresses of the recipients. This information is entirely separate from
1117any addresses contained in the header lines. The status of the message includes
1118a list of recipients who have already received the message. The format of the
9b371988 1119first spool file is described in chapter &<<CHAPspool>>&.
168e428f 1120
9b371988 1121.cindex "rewriting" "addresses"
168e428f 1122Address rewriting that is specified in the rewrite section of the configuration
9b371988 1123(see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
168e428f
PH
1124both in the header lines and the envelope, at the time the message is accepted.
1125If during the course of delivery additional addresses are generated (for
1126example, via aliasing), these new addresses are rewritten as soon as they are
1127generated. At the time a message is actually delivered (transported) further
1128rewriting can take place; because this is a transport option, it can be
1129different for different forms of delivery. It is also possible to specify the
1130addition or removal of certain header lines at the time the message is
9b371988
PH
1131delivered (see chapters &<<CHAProutergeneric>>& and
1132&<<CHAPtransportgeneric>>&).
168e428f
PH
1133
1134
1135
f89d2485 1136.section "Life of a message" "SECID15"
9b371988
PH
1137.cindex "message" "life of"
1138.cindex "message" "frozen"
168e428f
PH
1139A message remains in the spool directory until it is completely delivered to
1140its recipients or to an error address, or until it is deleted by an
1141administrator or by the user who originally created it. In cases when delivery
9b371988
PH
1142cannot proceed &-- for example, when a message can neither be delivered to its
1143recipients nor returned to its sender, the message is marked &"frozen"& on the
168e428f
PH
1144spool, and no more deliveries are attempted.
1145
9b371988
PH
1146.cindex "frozen messages" "thawing"
1147.cindex "message" "thawing frozen"
1148An administrator can &"thaw"& such messages when the problem has been
1149corrected, and can also freeze individual messages by hand if necessary. In
1150addition, an administrator can force a delivery error, causing a bounce message
1151to be sent.
1152
0a4e3112
PH
1153.oindex "&%timeout_frozen_after%&"
1154.oindex "&%ignore_bounce_errors_after%&"
9b371988
PH
1155There are options called &%ignore_bounce_errors_after%& and
1156&%timeout_frozen_after%&, which discard frozen messages after a certain time.
068aaea8 1157The first applies only to frozen bounces, the second to any frozen messages.
168e428f 1158
9b371988
PH
1159.cindex "message" "log file for"
1160.cindex "log" "file for each message"
168e428f 1161While Exim is working on a message, it writes information about each delivery
068aaea8 1162attempt to its main log file. This includes successful, unsuccessful, and
9b371988
PH
1163delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1164lines are also written to a separate &'message log'& file for each message.
1165These logs are solely for the benefit of the administrator, and are normally
1166deleted along with the spool files when processing of a message is complete.
168e428f 1167The use of individual message logs can be disabled by setting
9b371988
PH
1168&%no_message_logs%&; this might give an improvement in performance on very busy
1169systems.
168e428f 1170
9b371988
PH
1171.cindex "journal file"
1172.cindex "file" "journal"
168e428f
PH
1173All the information Exim itself needs to set up a delivery is kept in the first
1174spool file, along with the header lines. When a successful delivery occurs, the
1175address is immediately written at the end of a journal file, whose name is the
9b371988
PH
1176message id followed by &`-J`&. At the end of a delivery run, if there are some
1177addresses left to be tried again later, the first spool file (the &`-H`& file)
168e428f
PH
1178is updated to indicate which these are, and the journal file is then deleted.
1179Updating the spool file is done by writing a new file and renaming it, to
1180minimize the possibility of data loss.
1181
1182Should the system or the program crash after a successful delivery but before
1183the spool file has been updated, the journal is left lying around. The next
1184time Exim attempts to deliver the message, it reads the journal file and
1185updates the spool file before proceeding. This minimizes the chances of double
1186deliveries caused by crashes.
1187
1188
1189
9b371988
PH
1190.section "Processing an address for delivery" "SECTprocaddress"
1191.cindex "drivers" "definition of"
1192.cindex "router" "definition of"
1193.cindex "transport" "definition of"
1194The main delivery processing elements of Exim are called &'routers'& and
1195&'transports'&, and collectively these are known as &'drivers'&. Code for a
168e428f
PH
1196number of them is provided in the source distribution, and compile-time options
1197specify which ones are included in the binary. Run time options specify which
1198ones are actually used for delivering messages.
1199
9b371988
PH
1200.cindex "drivers" "instance definition"
1201Each driver that is specified in the run time configuration is an &'instance'&
168e428f 1202of that particular driver type. Multiple instances are allowed; for example,
9b371988 1203you can set up several different &(smtp)& transports, each with different
168e428f
PH
1204option values that might specify different ports or different timeouts. Each
1205instance has its own identifying name. In what follows we will normally use the
1206instance name when discussing one particular instance (that is, one specific
1207configuration of the driver), and the generic driver name when discussing
1208the driver's features in general.
1209
9b371988 1210A &'router'& is a driver that operates on an address, either determining how
068aaea8 1211its delivery should happen, by assigning it to a specific transport, or
168e428f
PH
1212converting the address into one or more new addresses (for example, via an
1213alias file). A router may also explicitly choose to fail an address, causing it
1214to be bounced.
1215
9b371988
PH
1216A &'transport'& is a driver that transmits a copy of the message from Exim's
1217spool to some destination. There are two kinds of transport: for a &'local'&
168e428f 1218transport, the destination is a file or a pipe on the local host, whereas for a
9b371988 1219&'remote'& transport the destination is some other host. A message is passed
168e428f
PH
1220to a specific transport as a result of successful routing. If a message has
1221several recipients, it may be passed to a number of different transports.
1222
9b371988 1223.cindex "preconditions" "definition of"
168e428f
PH
1224An address is processed by passing it to each configured router instance in
1225turn, subject to certain preconditions, until a router accepts the address or
1226specifies that it should be bounced. We will describe this process in more
068aaea8
PH
1227detail shortly. First, as a simple example, we consider how each recipient
1228address in a message is processed in a small configuration of three routers.
168e428f 1229
068aaea8 1230To make this a more concrete example, it is described in terms of some actual
168e428f
PH
1231routers, but remember, this is only an example. You can configure Exim's
1232routers in many different ways, and there may be any number of routers in a
1233configuration.
1234
1235The first router that is specified in a configuration is often one that handles
1236addresses in domains that are not recognized specially by the local host. These
1237are typically addresses for arbitrary domains on the Internet. A precondition
1238is set up which looks for the special domains known to the host (for example,
9b371988 1239its own domain name), and the router is run for addresses that do &'not'&
168e428f
PH
1240match. Typically, this is a router that looks up domains in the DNS in order to
1241find the hosts to which this address routes. If it succeeds, the address is
068aaea8 1242assigned to a suitable SMTP transport; if it does not succeed, the router is
168e428f
PH
1243configured to fail the address.
1244
068aaea8 1245The second router is reached only when the domain is recognized as one that
9b371988 1246&"belongs"& to the local host. This router does redirection &-- also known as
068aaea8
PH
1247aliasing and forwarding. When it generates one or more new addresses from the
1248original, each of them is routed independently from the start. Otherwise, the
1249router may cause an address to fail, or it may simply decline to handle the
1250address, in which case the address is passed to the next router.
168e428f
PH
1251
1252The final router in many configurations is one that checks to see if the
1253address belongs to a local mailbox. The precondition may involve a check to
1254see if the local part is the name of a login account, or it may look up the
1255local part in a file or a database. If its preconditions are not met, or if
1256the router declines, we have reached the end of the routers. When this happens,
1257the address is bounced.
1258
1259
1260
f89d2485 1261.section "Processing an address for verification" "SECID16"
9b371988
PH
1262.cindex "router" "for verification"
1263.cindex "verifying address" "overview"
168e428f 1264As well as being used to decide how to deliver to an address, Exim's routers
9b371988 1265are also used for &'address verification'&. Verification can be requested as
168e428f 1266one of the checks to be performed in an ACL for incoming messages, on both
9b371988
PH
1267sender and recipient addresses, and it can be tested using the &%-bv%& and
1268&%-bvs%& command line options.
168e428f 1269
9b371988 1270When an address is being verified, the routers are run in &"verify mode"&. This
168e428f
PH
1271does not affect the way the routers work, but it is a state that can be
1272detected. By this means, a router can be skipped or made to behave differently
1273when verifying. A common example is a configuration in which the first router
1274sends all messages to a message-scanning program, unless they have been
1275previously scanned. Thus, the first router accepts all addresses without any
9b371988 1276checking, making it useless for verifying. Normally, the &%no_verify%& option
168e428f
PH
1277would be set for such a router, causing it to be skipped in verify mode.
1278
1279
1280
1281
9b371988
PH
1282.section "Running an individual router" "SECTrunindrou"
1283.cindex "router" "running details"
1284.cindex "preconditions" "checking"
1285.cindex "router" "result of running"
168e428f
PH
1286As explained in the example above, a number of preconditions are checked before
1287running a router. If any are not met, the router is skipped, and the address is
9b371988 1288passed to the next router. When all the preconditions on a router &'are'& met,
168e428f
PH
1289the router is run. What happens next depends on the outcome, which is one of
1290the following:
1291
9b371988
PH
1292.ilist
1293&'accept'&: The router accepts the address, and either assigns it to a
1294transport, or generates one or more &"child"& addresses. Processing the
1295original address ceases,
0a4e3112 1296.oindex "&%unseen%&"
9b371988 1297unless the &%unseen%& option is set on the router. This option
168e428f 1298can be used to set up multiple deliveries with different routing (for example,
9b371988
PH
1299for keeping archive copies of messages). When &%unseen%& is set, the address is
1300passed to the next router. Normally, however, an &'accept'& return marks the
168e428f 1301end of routing.
9b371988 1302
068aaea8
PH
1303Any child addresses generated by the router are processed independently,
1304starting with the first router by default. It is possible to change this by
9b371988
PH
1305setting the &%redirect_router%& option to specify which router to start at for
1306child addresses. Unlike &%pass_router%& (see below) the router specified by
1307&%redirect_router%& may be anywhere in the router configuration.
1308.next
1309&'pass'&: The router recognizes the address, but cannot handle it itself. It
168e428f
PH
1310requests that the address be passed to another router. By default the address
1311is passed to the next router, but this can be changed by setting the
9b371988 1312&%pass_router%& option. However, (unlike &%redirect_router%&) the named router
168e428f 1313must be below the current router (to avoid loops).
9b371988
PH
1314.next
1315&'decline'&: The router declines to accept the address because it does not
168e428f 1316recognize it at all. By default, the address is passed to the next router, but
9b371988
PH
1317this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1318set, all the remaining routers are skipped. In effect, &%no_more%& converts
1319&'decline'& into &'fail'&.
1320.next
1321&'fail'&: The router determines that the address should fail, and queues it for
168e428f 1322the generation of a bounce message. There is no further processing of the
9b371988
PH
1323original address unless &%unseen%& is set on the router.
1324.next
1325&'defer'&: The router cannot handle the address at the present time. (A
068aaea8
PH
1326database may be offline, or a DNS lookup may have timed out.) No further
1327processing of the address happens in this delivery attempt. It is tried again
1328next time the message is considered for delivery.
9b371988
PH
1329.next
1330&'error'&: There is some error in the router (for example, a syntax error in
168e428f 1331its configuration). The action is as for defer.
9b371988 1332.endlist
168e428f
PH
1333
1334If an address reaches the end of the routers without having been accepted by
068aaea8 1335any of them, it is bounced as unrouteable. The default error message in this
9b371988
PH
1336situation is &"unrouteable address"&, but you can set your own message by
1337making use of the &%cannot_route_message%& option. This can be set for any
1338router; the value from the last router that &"saw"& the address is used.
168e428f
PH
1339
1340Sometimes while routing you want to fail a delivery when some conditions are
1341met but others are not, instead of passing the address on for further routing.
1342You can do this by having a second router that explicitly fails the delivery
9b371988 1343when the relevant conditions are met. The &(redirect)& router has a &"fail"&
168e428f
PH
1344facility for this purpose.
1345
1346
f89d2485 1347.section "Duplicate addresses" "SECID17"
9b371988 1348.cindex "case of local parts"
f89d2485 1349.cindex "address duplicate, discarding"
db9452a9 1350.cindex "duplicate addresses"
068aaea8
PH
1351Once routing is complete, Exim scans the addresses that are assigned to local
1352and remote transports, and discards any duplicates that it finds. During this
3cb1b51e 1353check, local parts are treated as case-sensitive. This happens only when
db9452a9 1354actually delivering a message; when testing routers with &%-bt%&, all the
3cb1b51e 1355routed addresses are shown.
db9452a9 1356
068aaea8 1357
168e428f 1358
9b371988 1359.section "Router preconditions" "SECTrouprecon"
f89d2485 1360.cindex "router" "preconditions, order of processing"
9b371988 1361.cindex "preconditions" "order of processing"
168e428f
PH
1362The preconditions that are tested for each router are listed below, in the
1363order in which they are tested. The individual configuration options are
9b371988 1364described in more detail in chapter &<<CHAProutergeneric>>&.
168e428f 1365
9b371988
PH
1366.ilist
1367The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
168e428f
PH
1368the local parts handled by the router may or must have certain prefixes and/or
1369suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1370skipped. These conditions are tested first. When an affix is present, it is
1371removed from the local part before further processing, including the evaluation
1372of any other conditions.
9b371988
PH
1373.next
1374Routers can be designated for use only when not verifying an address, that is,
168e428f 1375only when routing it for delivery (or testing its delivery routing). If the
9b371988 1376&%verify%& option is set false, the router is skipped when Exim is verifying an
168e428f 1377address.
9b371988
PH
1378Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1379&%verify_recipient%&, which independently control the use of the router for
168e428f
PH
1380sender and recipient verification. You can set these options directly if
1381you want a router to be used for only one type of verification.
6ece2e77 1382Note that cutthrough delivery is classed as a recipient verification for this purpose.
9b371988
PH
1383.next
1384If the &%address_test%& option is set false, the router is skipped when Exim is
1385run with the &%-bt%& option to test an address routing. This can be helpful
1386when the first router sends all new messages to a scanner of some sort; it
1387makes it possible to use &%-bt%& to test subsequent delivery routing without
1388having to simulate the effect of the scanner.
1389.next
1390Routers can be designated for use only when verifying an address, as
1391opposed to routing it for delivery. The &%verify_only%& option controls this.
6ece2e77 1392Again, cutthrough delivery counts as a verification.
9b371988
PH
1393.next
1394Individual routers can be explicitly skipped when running the routers to
1395check an address given in the SMTP EXPN command (see the &%expn%& option).
1396.next
1397If the &%domains%& option is set, the domain of the address must be in the set
068aaea8 1398of domains that it defines.
9b371988 1399.next
f89d2485
PH
1400.vindex "&$local_part_prefix$&"
1401.vindex "&$local_part$&"
1402.vindex "&$local_part_suffix$&"
9b371988
PH
1403If the &%local_parts%& option is set, the local part of the address must be in
1404the set of local parts that it defines. If &%local_part_prefix%& or
1405&%local_part_suffix%& is in use, the prefix or suffix is removed from the local
168e428f 1406part before this check. If you want to do precondition tests on local parts
9b371988
PH
1407that include affixes, you can do so by using a &%condition%& option (see below)
1408that uses the variables &$local_part$&, &$local_part_prefix$&, and
1409&$local_part_suffix$& as necessary.
1410.next
f89d2485
PH
1411.vindex "&$local_user_uid$&"
1412.vindex "&$local_user_gid$&"
1413.vindex "&$home$&"
9b371988 1414If the &%check_local_user%& option is set, the local part must be the name of
068aaea8 1415an account on the local host. If this check succeeds, the uid and gid of the
9b371988
PH
1416local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1417user's home directory is placed in &$home$&; these values can be used in the
1418remaining preconditions.
1419.next
1420If the &%router_home_directory%& option is set, it is expanded at this point,
1421because it overrides the value of &$home$&. If this expansion were left till
1422later, the value of &$home$& as set by &%check_local_user%& would be used in
1423subsequent tests. Having two different values of &$home$& in the same router
168e428f 1424could lead to confusion.
9b371988
PH
1425.next
1426If the &%senders%& option is set, the envelope sender address must be in the
1427set of addresses that it defines.
1428.next
1429If the &%require_files%& option is set, the existence or non-existence of
168e428f 1430specified files is tested.
9b371988
PH
1431.next
1432.cindex "customizing" "precondition"
1433If the &%condition%& option is set, it is evaluated and tested. This option
1434uses an expanded string to allow you to set up your own custom preconditions.
1435Expanded strings are described in chapter &<<CHAPexpand>>&.
1436.endlist
168e428f 1437
168e428f 1438
9b371988
PH
1439Note that &%require_files%& comes near the end of the list, so you cannot use
1440it to check for the existence of a file in which to lookup up a domain, local
168e428f 1441part, or sender. However, as these options are all expanded, you can use the
9b371988
PH
1442&%exists%& expansion condition to make such tests within each condition. The
1443&%require_files%& option is intended for checking files that the router may be
168e428f 1444going to use internally, or which are needed by a specific transport (for
9b371988 1445example, &_.procmailrc_&).
168e428f
PH
1446
1447
1448
f89d2485 1449.section "Delivery in detail" "SECID18"
9b371988 1450.cindex "delivery" "in detail"
168e428f
PH
1451When a message is to be delivered, the sequence of events is as follows:
1452
9b371988
PH
1453.ilist
1454If a system-wide filter file is specified, the message is passed to it. The
168e428f
PH
1455filter may add recipients to the message, replace the recipients, discard the
1456message, cause a new message to be generated, or cause the message delivery to
1457fail. The format of the system filter file is the same as for Exim user filter
9b371988
PH
1458files, described in the separate document entitled &'Exim's interfaces to mail
1459filtering'&.
1460.cindex "Sieve filter" "not available for system filter"
1461(&*Note*&: Sieve cannot be used for system filter files.)
1462
1463Some additional features are available in system filters &-- see chapter
1464&<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
168e428f
PH
1465filter only once per delivery attempt, however many recipients it has. However,
1466if there are several delivery attempts because one or more addresses could not
1467be immediately delivered, the system filter is run each time. The filter
9b371988 1468condition &%first_delivery%& can be used to detect the first run of the system
168e428f 1469filter.
9b371988
PH
1470.next
1471Each recipient address is offered to each configured router in turn, subject to
1472its preconditions, until one is able to handle it. If no router can handle the
1473address, that is, if they all decline, the address is failed. Because routers
1474can be targeted at particular domains, several locally handled domains can be
1475processed entirely independently of each other.
1476.next
1477.cindex "routing" "loops in"
1478.cindex "loop" "while routing"
1479A router that accepts an address may assign it to a local or a remote
1480transport. However, the transport is not run at this time. Instead, the address
1481is placed on a list for the particular transport, which will be run later.
068aaea8
PH
1482Alternatively, the router may generate one or more new addresses (typically
1483from alias, forward, or filter files). New addresses are fed back into this
1484process from the top, but in order to avoid loops, a router ignores any address
1485which has an identically-named ancestor that was processed by itself.
9b371988
PH
1486.next
1487When all the routing has been done, addresses that have been successfully
168e428f
PH
1488handled are passed to their assigned transports. When local transports are
1489doing real local deliveries, they handle only one address at a time, but if a
1490local transport is being used as a pseudo-remote transport (for example, to
1491collect batched SMTP messages for transmission by some other means) multiple
1492addresses can be handled. Remote transports can always handle more than one
1493address at a time, but can be configured not to do so, or to restrict multiple
1494addresses to the same domain.
9b371988
PH
1495.next
1496Each local delivery to a file or a pipe runs in a separate process under a
168e428f
PH
1497non-privileged uid, and these deliveries are run one at a time. Remote
1498deliveries also run in separate processes, normally under a uid that is private
9b371988 1499to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
168e428f 1500run in parallel. The maximum number of simultaneous remote deliveries for any
9b371988 1501one message is set by the &%remote_max_parallel%& option.
168e428f
PH
1502The order in which deliveries are done is not defined, except that all local
1503deliveries happen before any remote deliveries.
9b371988
PH
1504.next
1505.cindex "queue runner"
168e428f
PH
1506When it encounters a local delivery during a queue run, Exim checks its retry
1507database to see if there has been a previous temporary delivery failure for the
1508address before running the local transport. If there was a previous failure,
1509Exim does not attempt a new delivery until the retry time for the address is
1510reached. However, this happens only for delivery attempts that are part of a
1511queue run. Local deliveries are always attempted when delivery immediately
1512follows message reception, even if retry times are set for them. This makes for
1513better behaviour if one particular message is causing problems (for example,
1514causing quota overflow, or provoking an error in a filter file).
9b371988
PH
1515.next
1516.cindex "delivery" "retry in remote transports"
168e428f
PH
1517Remote transports do their own retry handling, since an address may be
1518deliverable to one of a number of hosts, each of which may have a different
1519retry time. If there have been previous temporary failures and no host has
1520reached its retry time, no delivery is attempted, whether in a queue run or
9b371988
PH
1521not. See chapter &<<CHAPretry>>& for details of retry strategies.
1522.next
1523If there were any permanent errors, a bounce message is returned to an
168e428f
PH
1524appropriate address (the sender in the common case), with details of the error
1525for each failing address. Exim can be configured to send copies of bounce
1526messages to other addresses.
9b371988
PH
1527.next
1528.cindex "delivery" "deferral"
168e428f
PH
1529If one or more addresses suffered a temporary failure, the message is left on
1530the queue, to be tried again later. Delivery of these addresses is said to be
9b371988
PH
1531&'deferred'&.
1532.next
1533When all the recipient addresses have either been delivered or bounced,
168e428f
PH
1534handling of the message is complete. The spool files and message log are
1535deleted, though the message log can optionally be preserved if required.
9b371988 1536.endlist
168e428f
PH
1537
1538
1539
1540
f89d2485 1541.section "Retry mechanism" "SECID19"
9b371988
PH
1542.cindex "delivery" "retry mechanism"
1543.cindex "retry" "description of mechanism"
1544.cindex "queue runner"
168e428f
PH
1545Exim's mechanism for retrying messages that fail to get delivered at the first
1546attempt is the queue runner process. You must either run an Exim daemon that
9b371988
PH
1547uses the &%-q%& option with a time interval to start queue runners at regular
1548intervals, or use some other means (such as &'cron'&) to start them. If you do
168e428f
PH
1549not arrange for queue runners to be run, messages that fail temporarily at the
1550first attempt will remain on your queue for ever. A queue runner process works
068aaea8 1551its way through the queue, one message at a time, trying each delivery that has
168e428f
PH
1552passed its retry time.
1553You can run several queue runners at once.
1554
1555Exim uses a set of configured rules to determine when next to retry the failing
9b371988
PH
1556address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1557should give up trying to deliver to the address, at which point it generates a
1558bounce message. If no retry rules are set for a particular host, address, and
1559error combination, no retries are attempted, and temporary errors are treated
1560as permanent.
168e428f
PH
1561
1562
1563
f89d2485 1564.section "Temporary delivery failure" "SECID20"
9b371988 1565.cindex "delivery" "temporary failure"
168e428f
PH
1566There are many reasons why a message may not be immediately deliverable to a
1567particular address. Failure to connect to a remote machine (because it, or the
1568connection to it, is down) is one of the most common. Temporary failures may be
1569detected during routing as well as during the transport stage of delivery.
1570Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1571is on a file system where the user is over quota. Exim can be configured to
1572impose its own quotas on local mailboxes; where system quotas are set they will
1573also apply.
1574
1575If a host is unreachable for a period of time, a number of messages may be
1576waiting for it by the time it recovers, and sending them in a single SMTP
1577connection is clearly beneficial. Whenever a delivery to a remote host is
1578deferred,
fa41615d 1579.cindex "hints database" "deferred deliveries"
168e428f
PH
1580Exim makes a note in its hints database, and whenever a successful
1581SMTP delivery has happened, it looks to see if any other messages are waiting
1582for the same host. If any are found, they are sent over the same SMTP
1583connection, subject to a configuration limit as to the maximum number in any
1584one connection.
168e428f
PH
1585
1586
1587
f89d2485 1588.section "Permanent delivery failure" "SECID21"
9b371988
PH
1589.cindex "delivery" "permanent failure"
1590.cindex "bounce message" "when generated"
168e428f
PH
1591When a message cannot be delivered to some or all of its intended recipients, a
1592bounce message is generated. Temporary delivery failures turn into permanent
1593errors when their timeout expires. All the addresses that fail in a given
1594delivery attempt are listed in a single message. If the original message has
1595many recipients, it is possible for some addresses to fail in one delivery
1596attempt and others to fail subsequently, giving rise to more than one bounce
1597message. The wording of bounce messages can be customized by the administrator.
9b371988 1598See chapter &<<CHAPemsgcust>>& for details.
168e428f 1599
9b371988
PH
1600.cindex "&'X-Failed-Recipients:'& header line"
1601Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
168e428f
PH
1602failed addresses, for the benefit of programs that try to analyse such messages
1603automatically.
1604
9b371988 1605.cindex "bounce message" "recipient of"
168e428f
PH
1606A bounce message is normally sent to the sender of the original message, as
1607obtained from the message's envelope. For incoming SMTP messages, this is the
9b371988
PH
1608address given in the MAIL command. However, when an address is expanded via a
1609forward or alias file, an alternative address can be specified for delivery
1610failures of the generated addresses. For a mailing list expansion (see section
1611&<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1612of the list.
168e428f
PH
1613
1614
1615
f89d2485 1616.section "Failures to deliver bounce messages" "SECID22"
9b371988 1617.cindex "bounce message" "failure to deliver"
168e428f
PH
1618If a bounce message (either locally generated or received from a remote host)
1619itself suffers a permanent delivery failure, the message is left on the queue,
1620but it is frozen, awaiting the attention of an administrator. There are options
068aaea8 1621that can be used to make Exim discard such failed messages, or to keep them
9b371988
PH
1622for only a short time (see &%timeout_frozen_after%& and
1623&%ignore_bounce_errors_after%&).
168e428f
PH
1624
1625
1626
1627
1628
9b371988
PH
1629. ////////////////////////////////////////////////////////////////////////////
1630. ////////////////////////////////////////////////////////////////////////////
168e428f 1631
f89d2485 1632.chapter "Building and installing Exim" "CHID3"
4f578862 1633.scindex IIDbuex "building Exim"
168e428f 1634
f89d2485
PH
1635.section "Unpacking" "SECID23"
1636Exim is distributed as a gzipped or bzipped tar file which, when unpacked,
168e428f 1637creates a directory with the name of the current release (for example,
2aee48d6 1638&_exim-&version()_&) into which the following files are placed:
9b371988
PH
1639
1640.table2 140pt
f89d2485
PH
1641.irow &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1642.irow &_CHANGES_& "contains a reference to where changes are &&&
1643 documented"
1644.irow &_LICENCE_& "the GNU General Public Licence"
1645.irow &_Makefile_& "top-level make file"
1646.irow &_NOTICE_& "conditions for the use of Exim"
1647.irow &_README_& "list of files, directories and simple build &&&
1648 instructions"
9b371988
PH
1649.endtable
1650
1651Other files whose names begin with &_README_& may also be present. The
168e428f
PH
1652following subdirectories are created:
1653
9b371988 1654.table2 140pt
f89d2485
PH
1655.irow &_Local_& "an empty directory for local configuration files"
1656.irow &_OS_& "OS-specific files"
1657.irow &_doc_& "documentation files"
1658.irow &_exim_monitor_& "source files for the Exim monitor"
1659.irow &_scripts_& "scripts used in the build process"
1660.irow &_src_& "remaining source files"
1661.irow &_util_& "independent utilities"
9b371988
PH
1662.endtable
1663
1664The main utility programs are contained in the &_src_& directory, and are built
1665with the Exim binary. The &_util_& directory contains a few optional scripts
168e428f
PH
1666that may be useful to some sites.
1667
1668
f89d2485 1669.section "Multiple machine architectures and operating systems" "SECID24"
9b371988 1670.cindex "building Exim" "multiple OS/architectures"
168e428f
PH
1671The building process for Exim is arranged to make it easy to build binaries for
1672a number of different architectures and operating systems from the same set of
9b371988
PH
1673source files. Compilation does not take place in the &_src_& directory.
1674Instead, a &'build directory'& is created for each architecture and operating
1675system.
1676.cindex "symbolic link" "to build directory"
168e428f 1677Symbolic links to the sources are installed in this directory, which is where
9b371988
PH
1678the actual building takes place. In most cases, Exim can discover the machine
1679architecture and operating system for itself, but the defaults can be
1680overridden if necessary.
168e428f 1681
168e428f 1682
8473d4ee 1683.section "PCRE library" "SECTpcre"
210f147e
NM
1684.cindex "PCRE library"
1685Exim no longer has an embedded PCRE library as the vast majority of
1686modern systems include PCRE as a system library, although you may need
1687to install the PCRE or PCRE development package for your operating
1688system. If your system has a normal PCRE installation the Exim build
1689process will need no further configuration. If the library or the
6a6084f8
PP
1690headers are in an unusual location you will need to either set the PCRE_LIBS
1691and INCLUDE directives appropriately,
1692or set PCRE_CONFIG=yes to use the installed &(pcre-config)& command.
1693If your operating system has no
210f147e
NM
1694PCRE support then you will need to obtain and build the current PCRE
1695from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/).
6a6084f8 1696More information on PCRE is available at &url(http://www.pcre.org/).
210f147e 1697
9b371988
PH
1698.section "DBM libraries" "SECTdb"
1699.cindex "DBM libraries" "discussion of"
1700.cindex "hints database" "DBM files used for"
168e428f
PH
1701Even if you do not use any DBM files in your configuration, Exim still needs a
1702DBM library in order to operate, because it uses indexed files for its hints
1703databases. Unfortunately, there are a number of DBM libraries in existence, and
1704different operating systems often have different ones installed.
1705
9b371988 1706.cindex "Solaris" "DBM library for"
f89d2485
PH
1707.cindex "IRIX, DBM library for"
1708.cindex "BSD, DBM library for"
1709.cindex "Linux, DBM library for"
168e428f
PH
1710If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1711Linux distribution, the DBM configuration should happen automatically, and you
1712may be able to ignore this section. Otherwise, you may have to learn more than
1713you would like about DBM libraries from what follows.
1714
9b371988 1715.cindex "&'ndbm'& DBM library"
168e428f 1716Licensed versions of Unix normally contain a library of DBM functions operating
9b371988 1717via the &'ndbm'& interface, and this is what Exim expects by default. Free
168e428f
PH
1718versions of Unix seem to vary in what they contain as standard. In particular,
1719some early versions of Linux have no default DBM library, and different
1720distributors have chosen to bundle different libraries with their packaged
f89d2485 1721versions. However, the more recent releases seem to have standardized on the
168e428f
PH
1722Berkeley DB library.
1723
1724Different DBM libraries have different conventions for naming the files they
9b371988 1725use. When a program opens a file called &_dbmfile_&, there are several
168e428f
PH
1726possibilities:
1727
9b371988
PH
1728.olist
1729A traditional &'ndbm'& implementation, such as that supplied as part of
1730Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1731.next
1732.cindex "&'gdbm'& DBM library"
1733The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
168e428f 1734compatibility interface it makes two different hard links to it with names
9b371988 1735&_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
168e428f 1736file name is used unmodified.
9b371988
PH
1737.next
1738.cindex "Berkeley DB library"
1739The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1740operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1741programmer exactly the same as the traditional &'ndbm'& implementation.
1742.next
1743If the Berkeley package is used in its native mode, it operates on a single
1744file called &_dbmfile_&; the programmer's interface is somewhat different to
1745the traditional &'ndbm'& interface.
1746.next
1747To complicate things further, there are several very different versions of the
168e428f 1748Berkeley DB package. Version 1.85 was stable for a very long time, releases
9b371988
PH
17492.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1750numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
168e428f 1751versions of Berkeley DB can be obtained from
9b371988
PH
1752&url(http://www.sleepycat.com/).
1753.next
1754.cindex "&'tdb'& DBM library"
1755Yet another DBM library, called &'tdb'&, is available from
1756&url(http://download.sourceforge.net/tdb). It has its own interface, and also
1757operates on a single file.
1758.endlist
1759
1760.cindex "USE_DB"
1761.cindex "DBM libraries" "configuration for building"
168e428f
PH
1762Exim and its utilities can be compiled to use any of these interfaces. In order
1763to use any version of the Berkeley DB package in native mode, you must set
1764USE_DB in an appropriate configuration file (typically
9b371988
PH
1765&_Local/Makefile_&). For example:
1766.code
1767USE_DB=yes
1768.endd
168e428f
PH
1769Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1770error is diagnosed if you set more than one of these.
1771
1772At the lowest level, the build-time configuration sets none of these options,
1773thereby assuming an interface of type (1). However, some operating system
1774configuration files (for example, those for the BSD operating systems and
1775Linux) assume type (4) by setting USE_DB as their default, and the
1776configuration files for Cygwin set USE_GDBM. Anything you set in
9b371988 1777&_Local/Makefile_&, however, overrides these system defaults.
168e428f
PH
1778
1779As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1780necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1781in one of these lines:
9b371988
PH
1782.code
1783DBMLIB = -ldb
1784DBMLIB = -ltdb
1785.endd
168e428f
PH
1786Settings like that will work if the DBM library is installed in the standard
1787place. Sometimes it is not, and the library's header file may also not be in
1788the default path. You may need to set INCLUDE to specify where the header
1789file is, and to specify the path to the library more fully in DBMLIB, as in
1790this example:
9b371988
PH
1791.code
1792INCLUDE=-I/usr/local/include/db-4.1
1793DBMLIB=/usr/local/lib/db-4.1/libdb.a
1794.endd
168e428f 1795There is further detailed discussion about the various DBM libraries in the
9b371988 1796file &_doc/dbm.discuss.txt_& in the Exim distribution.
168e428f
PH
1797
1798
1799
f89d2485 1800.section "Pre-building configuration" "SECID25"
9b371988
PH
1801.cindex "building Exim" "pre-building configuration"
1802.cindex "configuration for building Exim"
1803.cindex "&_Local/Makefile_&"
1804.cindex "&_src/EDITME_&"
168e428f
PH
1805Before building Exim, a local configuration file that specifies options
1806independent of any operating system has to be created with the name
9b371988
PH
1807&_Local/Makefile_&. A template for this file is supplied as the file
1808&_src/EDITME_&, and it contains full descriptions of all the option settings
168e428f
PH
1809therein. These descriptions are therefore not repeated here. If you are
1810building Exim for the first time, the simplest thing to do is to copy
9b371988 1811&_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
168e428f
PH
1812
1813There are three settings that you must supply, because Exim will not build
1814without them. They are the location of the run time configuration file
1815(CONFIGURE_FILE), the directory in which Exim binaries will be installed
1816(BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1817maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1818a colon-separated list of file names; Exim uses the first of them that exists.
1819
1820There are a few other parameters that can be specified either at build time or
1821at run time, to enable the same binary to be used on a number of different
1822machines. However, if the locations of Exim's spool directory and log file
1823directory (if not within the spool directory) are fixed, it is recommended that
9b371988 1824you specify them in &_Local/Makefile_& instead of at run time, so that errors
168e428f
PH
1825detected early in Exim's execution (such as a malformed configuration file) can
1826be logged.
1827
9b371988 1828.cindex "content scanning" "specifying at build time"
068aaea8 1829Exim's interfaces for calling virus and spam scanning software directly from
168e428f
PH
1830access control lists are not compiled by default. If you want to include these
1831facilities, you need to set
9b371988
PH
1832.code
1833WITH_CONTENT_SCAN=yes
1834.endd
1835in your &_Local/Makefile_&. For details of the facilities themselves, see
1836chapter &<<CHAPexiscan>>&.
168e428f
PH
1837
1838
9b371988 1839.cindex "&_Local/eximon.conf_&"
3cb1b51e 1840.cindex "&_exim_monitor/EDITME_&"
168e428f 1841If you are going to build the Exim monitor, a similar configuration process is
9b371988
PH
1842required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1843your installation and saved under the name &_Local/eximon.conf_&. If you are
1844happy with the default settings described in &_exim_monitor/EDITME_&,
1845&_Local/eximon.conf_& can be empty, but it must exist.
168e428f
PH
1846
1847This is all the configuration that is needed in straightforward cases for known
1848operating systems. However, the building process is set up so that it is easy
1849to override options that are set by default or by operating-system-specific
1850configuration files, for example to change the name of the C compiler, which
9b371988
PH
1851defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1852do this.
168e428f
PH
1853
1854
1855
f89d2485 1856.section "Support for iconv()" "SECID26"
9b371988
PH
1857.cindex "&[iconv()]& support"
1858.cindex "RFC 2047"
168e428f
PH
1859The contents of header lines in messages may be encoded according to the rules
1860described RFC 2047. This makes it possible to transmit characters that are not
1861in the ASCII character set, and to label them as being in a particular
9b371988 1862character set. When Exim is inspecting header lines by means of the &%$h_%&
168e428f 1863mechanism, it decodes them, and translates them into a specified character set
1459a03d 1864(default is set at build time). The translation is possible only if the operating system
9b371988
PH
1865supports the &[iconv()]& function.
1866
1867However, some of the operating systems that supply &[iconv()]& do not support
1868very many conversions. The GNU &%libiconv%& library (available from
1869&url(http://www.gnu.org/software/libiconv/)) can be installed on such
1870systems to remedy this deficiency, as well as on systems that do not supply
1871&[iconv()]& at all. After installing &%libiconv%&, you should add
1872.code
1873HAVE_ICONV=yes
1874.endd
1875to your &_Local/Makefile_& and rebuild Exim.
1876
1877
1878
1879.section "Including TLS/SSL encryption support" "SECTinctlsssl"
1880.cindex "TLS" "including support for TLS"
1881.cindex "encryption" "including support for"
1882.cindex "SUPPORT_TLS"
1883.cindex "OpenSSL" "building Exim with"
1884.cindex "GnuTLS" "building Exim with"
168e428f
PH
1885Exim can be built to support encrypted SMTP connections, using the STARTTLS
1886command as per RFC 2487. It can also support legacy clients that expect to
1887start a TLS session immediately on connection to a non-standard port (see the
9b371988 1888&%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
168e428f
PH
1889line option).
1890
1891If you want to build Exim with TLS support, you must first install either the
1892OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1893implementing SSL.
1894
1895If OpenSSL is installed, you should set
9b371988
PH
1896.code
1897SUPPORT_TLS=yes
1898TLS_LIBS=-lssl -lcrypto
1899.endd
1900in &_Local/Makefile_&. You may also need to specify the locations of the
168e428f 1901OpenSSL library and include files. For example:
9b371988
PH
1902.code
1903SUPPORT_TLS=yes
1904TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1905TLS_INCLUDE=-I/usr/local/openssl/include/
1906.endd
7e6a8985
PP
1907.cindex "pkg-config" "OpenSSL"
1908If you have &'pkg-config'& available, then instead you can just use:
1909.code
1910SUPPORT_TLS=yes
1911USE_OPENSSL_PC=openssl
1912.endd
9b371988 1913.cindex "USE_GNUTLS"
168e428f 1914If GnuTLS is installed, you should set
9b371988
PH
1915.code
1916SUPPORT_TLS=yes
1917USE_GNUTLS=yes
1918TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1919.endd
1920in &_Local/Makefile_&, and again you may need to specify the locations of the
168e428f 1921library and include files. For example:
9b371988
PH
1922.code
1923SUPPORT_TLS=yes
1924USE_GNUTLS=yes
1925TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1926TLS_INCLUDE=-I/usr/gnu/include
1927.endd
7e6a8985
PP
1928.cindex "pkg-config" "GnuTLS"
1929If you have &'pkg-config'& available, then instead you can just use:
1930.code
1931SUPPORT_TLS=yes
1932USE_GNUTLS=yes
1933USE_GNUTLS_PC=gnutls
1934.endd
7e6a8985 1935
168e428f 1936You do not need to set TLS_INCLUDE if the relevant directory is already
9b371988
PH
1937specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1938given in chapter &<<CHAPTLS>>&.
168e428f
PH
1939
1940
1941
1942
b52ed2b3
NM
1943.section "Use of tcpwrappers" "SECID27"
1944
f89d2485 1945.cindex "tcpwrappers, building Exim to support"
9b371988 1946.cindex "USE_TCP_WRAPPERS"
5dc43717
JJ
1947.cindex "TCP_WRAPPERS_DAEMON_NAME"
1948.cindex "tcp_wrappers_daemon_name"
9b371988
PH
1949Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1950SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
168e428f 1951alternative to Exim's own checking facilities for installations that are
9b371988
PH
1952already making use of &'tcpwrappers'& for other purposes. To do this, you
1953should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1954&_tcpd.h_& to be available at compile time, and also ensure that the library
1955&_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1956EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1957you might have
1958.code
1959USE_TCP_WRAPPERS=yes
1960CFLAGS=-O -I/usr/local/include
1961EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1962.endd
5dc43717
JJ
1963in &_Local/Makefile_&. The daemon name to use in the &'tcpwrappers'& control
1964files is &"exim"&. For example, the line
9b371988
PH
1965.code
1966exim : LOCAL 192.168.1. .friendly.domain.example
1967.endd
1968in your &_/etc/hosts.allow_& file allows connections from the local host, from
1969the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&.
5dc43717
JJ
1970All other connections are denied. The daemon name used by &'tcpwrappers'&
1971can be changed at build time by setting TCP_WRAPPERS_DAEMON_NAME in
a543079f 1972&_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the
5dc43717 1973configure file. Consult the &'tcpwrappers'& documentation for
168e428f 1974further details.
168e428f
PH
1975
1976
f89d2485 1977.section "Including support for IPv6" "SECID28"
9b371988 1978.cindex "IPv6" "including support for"
168e428f 1979Exim contains code for use on systems that have IPv6 support. Setting
9b371988 1980&`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
168e428f
PH
1981it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1982where the IPv6 support is not fully integrated into the normal include and
1983library files.
1984
1985Two different types of DNS record for handling IPv6 addresses have been
f89d2485 1986defined. AAAA records (analogous to A records for IPv4) are in use, and are
168e428f
PH
1987currently seen as the mainstream. Another record type called A6 was proposed
1988as better than AAAA because it had more flexibility. However, it was felt to be
badb25a9 1989over-complex, and its status was reduced to &"experimental"&.
badb25a9 1990Exim used to
cc00f4af
JH
1991have a compile option for including A6 record support but this has now been
1992withdrawn.
168e428f
PH
1993
1994
1995
0a349494
PP
1996.section "Dynamically loaded lookup module support" "SECTdynamicmodules"
1997.cindex "lookup modules"
1998.cindex "dynamic modules"
1999.cindex ".so building"
2000On some platforms, Exim supports not compiling all lookup types directly into
2001the main binary, instead putting some into external modules which can be loaded
2002on demand.
2003This permits packagers to build Exim with support for lookups with extensive
2004library dependencies without requiring all users to install all of those
2005dependencies.
2006Most, but not all, lookup types can be built this way.
2007
2008Set &`LOOKUP_MODULE_DIR`& to the directory into which the modules will be
2009installed; Exim will only load modules from that directory, as a security
2010measure. You will need to set &`CFLAGS_DYNAMIC`& if not already defined
2011for your OS; see &_OS/Makefile-Linux_& for an example.
2012Some other requirements for adjusting &`EXTRALIBS`& may also be necessary,
2013see &_src/EDITME_& for details.
2014
2015Then, for each module to be loaded dynamically, define the relevant
2016&`LOOKUP_`&<&'lookup_type'&> flags to have the value "2" instead of "yes".
2017For example, this will build in lsearch but load sqlite and mysql support
2018on demand:
2019.code
2020LOOKUP_LSEARCH=yes
2021LOOKUP_SQLITE=2
2022LOOKUP_MYSQL=2
2023.endd
5d758a46 2024
0a349494 2025
f89d2485 2026.section "The building process" "SECID29"
9b371988
PH
2027.cindex "build directory"
2028Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
2029created, run &'make'& at the top level. It determines the architecture and
168e428f
PH
2030operating system types, and creates a build directory if one does not exist.
2031For example, on a Sun system running Solaris 8, the directory
9b371988
PH
2032&_build-SunOS5-5.8-sparc_& is created.
2033.cindex "symbolic link" "to source files"
168e428f
PH
2034Symbolic links to relevant source files are installed in the build directory.
2035
9b371988 2036If this is the first time &'make'& has been run, it calls a script that builds
168e428f 2037a make file inside the build directory, using the configuration files from the
9b371988
PH
2038&_Local_& directory. The new make file is then passed to another instance of
2039&'make'&. This does the real work, building a number of utility scripts, and
168e428f 2040then compiling and linking the binaries for the Exim monitor (if configured), a
9b371988
PH
2041number of utility programs, and finally Exim itself. The command &`make
2042makefile`& can be used to force a rebuild of the make file in the build
168e428f
PH
2043directory, should this ever be necessary.
2044
2045If you have problems building Exim, check for any comments there may be in the
9b371988 2046&_README_& file concerning your operating system, and also take a look at the
168e428f
PH
2047FAQ, where some common problems are covered.
2048
2049
2050
f89d2485 2051.section 'Output from &"make"&' "SECID283"
9b371988 2052The output produced by the &'make'& process for compile lines is often very
068aaea8
PH
2053unreadable, because these lines can be very long. For this reason, the normal
2054output is suppressed by default, and instead output similar to that which
2055appears when compiling the 2.6 Linux kernel is generated: just a short line for
2056each module that is being compiled or linked. However, it is still possible to
9b371988
PH
2057get the full output, by calling &'make'& like this:
2058.code
2059FULLECHO='' make -e
2060.endd
2061The value of FULLECHO defaults to &"@"&, the flag character that suppresses
2062command reflection in &'make'&. When you ask for the full output, it is
3cb1b51e 2063given in addition to the short output.
068aaea8
PH
2064
2065
2066
9b371988 2067.section "Overriding build-time options for Exim" "SECToverride"
f89d2485 2068.cindex "build-time options, overriding"
168e428f
PH
2069The main make file that is created at the beginning of the building process
2070consists of the concatenation of a number of files which set configuration
9b371988 2071values, followed by a fixed set of &'make'& instructions. If a value is set
168e428f
PH
2072more than once, the last setting overrides any previous ones. This provides a
2073convenient way of overriding defaults. The files that are concatenated are, in
2074order:
9b371988
PH
2075.display
2076&_OS/Makefile-Default_&
2077&_OS/Makefile-_&<&'ostype'&>
2078&_Local/Makefile_&
2079&_Local/Makefile-_&<&'ostype'&>
2080&_Local/Makefile-_&<&'archtype'&>
2081&_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
2082&_OS/Makefile-Base_&
2083.endd
2084.cindex "&_Local/Makefile_&"
2085.cindex "building Exim" "operating system type"
2086.cindex "building Exim" "architecture type"
2087where <&'ostype'&> is the operating system type and <&'archtype'&> is the
2088architecture type. &_Local/Makefile_& is required to exist, and the building
2089process fails if it is absent. The other three &_Local_& files are optional,
168e428f
PH
2090and are often not needed.
2091
9b371988
PH
2092The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
2093called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
168e428f
PH
2094the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
2095values are used, thereby providing a means of forcing particular settings.
9b371988 2096Otherwise, the scripts try to get values from the &%uname%& command. If this
168e428f 2097fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
9b371988 2098of &'ad hoc'& transformations are then applied, to produce the standard names
168e428f
PH
2099that Exim expects. You can run these scripts directly from the shell in order
2100to find out what values are being used on your system.
2101
2102
9b371988 2103&_OS/Makefile-Default_& contains comments about the variables that are set
168e428f
PH
2104therein. Some (but not all) are mentioned below. If there is something that
2105needs changing, review the contents of this file and the contents of the make
9b371988 2106file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
168e428f
PH
2107default values are.
2108
2109
9b371988
PH
2110.cindex "building Exim" "overriding default settings"
2111If you need to change any of the values that are set in &_OS/Makefile-Default_&
2112or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
168e428f 2113need to change the original files. Instead, you should make the changes by
9b371988
PH
2114putting the new values in an appropriate &_Local_& file. For example,
2115.cindex "Tru64-Unix build-time settings"
168e428f
PH
2116when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2117formerly DEC-OSF1) operating system, it is necessary to specify that the C
9b371988
PH
2118compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2119called with the option &%-std1%&, to make it recognize some of the features of
168e428f 2120Standard C that Exim uses. (Most other compilers recognize Standard C by
9b371988 2121default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
168e428f 2122containing the lines
9b371988
PH
2123.code
2124CC=cc
2125CFLAGS=-std1
2126.endd
168e428f 2127If you are compiling for just one operating system, it may be easier to put
9b371988 2128these lines directly into &_Local/Makefile_&.
168e428f
PH
2129
2130Keeping all your local configuration settings separate from the distributed
2131files makes it easy to transfer them to new versions of Exim simply by copying
9b371988 2132the contents of the &_Local_& directory.
168e428f
PH
2133
2134
9b371988
PH
2135.cindex "NIS lookup type" "including support for"
2136.cindex "NIS+ lookup type" "including support for"
2137.cindex "LDAP" "including support for"
2138.cindex "lookup" "inclusion in binary"
168e428f
PH
2139Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2140lookup, but not all systems have these components installed, so the default is
2141not to include the relevant code in the binary. All the different kinds of file
2142and database lookup that Exim supports are implemented as separate code modules
2143which are included only if the relevant compile-time options are set. In the
9b371988
PH
2144case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2145.code
2146LOOKUP_LDAP=yes
2147LOOKUP_NIS=yes
2148LOOKUP_NISPLUS=yes
2149.endd
168e428f 2150and similar settings apply to the other lookup types. They are all listed in
9b371988 2151&_src/EDITME_&. In many cases the relevant include files and interface
168e428f 2152libraries need to be installed before compiling Exim.
9b371988 2153.cindex "cdb" "including support for"
068aaea8
PH
2154However, there are some optional lookup types (such as cdb) for which
2155the code is entirely contained within Exim, and no external include
168e428f
PH
2156files or libraries are required. When a lookup type is not included in the
2157binary, attempts to configure Exim to use it cause run time configuration
2158errors.
2159
7e6a8985
PP
2160.cindex "pkg-config" "lookups"
2161.cindex "pkg-config" "authenticators"
252e0c7b
PP
2162Many systems now use a tool called &'pkg-config'& to encapsulate information
2163about how to compile against a library; Exim has some initial support for
2164being able to use pkg-config for lookups and authenticators. For any given
2165makefile variable which starts &`LOOKUP_`& or &`AUTH_`&, you can add a new
2166variable with the &`_PC`& suffix in the name and assign as the value the
2167name of the package to be queried. The results of querying via the
2168&'pkg-config'& command will be added to the appropriate Makefile variables
2169with &`+=`& directives, so your version of &'make'& will need to support that
2170syntax. For instance:
2171.code
2172LOOKUP_SQLITE=yes
2173LOOKUP_SQLITE_PC=sqlite3
2174AUTH_GSASL=yes
2175AUTH_GSASL_PC=libgsasl
2176AUTH_HEIMDAL_GSSAPI=yes
2177AUTH_HEIMDAL_GSSAPI_PC=heimdal-gssapi
2178.endd
252e0c7b 2179
9b371988 2180.cindex "Perl" "including support for"
168e428f
PH
2181Exim can be linked with an embedded Perl interpreter, allowing Perl
2182subroutines to be called during string expansion. To enable this facility,
9b371988
PH
2183.code
2184EXIM_PERL=perl.o
2185.endd
2186must be defined in &_Local/Makefile_&. Details of this facility are given in
2187chapter &<<CHAPperl>>&.
168e428f 2188
f89d2485 2189.cindex "X11 libraries, location of"
168e428f 2190The location of the X11 libraries is something that varies a lot between
068aaea8 2191operating systems, and there may be different versions of X11 to cope
168e428f
PH
2192with. Exim itself makes no use of X11, but if you are compiling the Exim
2193monitor, the X11 libraries must be available.
9b371988
PH
2194The following three variables are set in &_OS/Makefile-Default_&:
2195.code
2196X11=/usr/X11R6
2197XINCLUDE=-I$(X11)/include
2198XLFLAGS=-L$(X11)/lib
2199.endd
168e428f 2200These are overridden in some of the operating-system configuration files. For
9b371988
PH
2201example, in &_OS/Makefile-SunOS5_& there is
2202.code
2203X11=/usr/openwin
2204XINCLUDE=-I$(X11)/include
2205XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2206.endd
168e428f
PH
2207If you need to override the default setting for your operating system, place a
2208definition of all three of these variables into your
9b371988 2209&_Local/Makefile-<ostype>_& file.
168e428f 2210
9b371988 2211.cindex "EXTRALIBS"
168e428f
PH
2212If you need to add any extra libraries to the link steps, these can be put in a
2213variable called EXTRALIBS, which appears in all the link commands, but by
2214default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2215command for linking the main Exim binary, and not for any associated utilities.
2216
9b371988 2217.cindex "DBM libraries" "configuration for building"
168e428f 2218There is also DBMLIB, which appears in the link commands for binaries that
9b371988 2219use DBM functions (see also section &<<SECTdb>>&). Finally, there is
168e428f
PH
2220EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2221binary, and which can be used, for example, to include additional X11
2222libraries.
2223
9b371988 2224.cindex "configuration file" "editing"
168e428f
PH
2225The make file copes with rebuilding Exim correctly if any of the configuration
2226files are edited. However, if an optional configuration file is deleted, it is
9b371988
PH
2227necessary to touch the associated non-optional file (that is,
2228&_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
168e428f
PH
2229
2230
f89d2485 2231.section "OS-specific header files" "SECID30"
9b371988
PH
2232.cindex "&_os.h_&"
2233.cindex "building Exim" "OS-specific C header files"
2234The &_OS_& directory contains a number of files with names of the form
2235&_os.h-<ostype>_&. These are system-specific C header files that should not
168e428f 2236normally need to be changed. There is a list of macro settings that are
9b371988 2237recognized in the file &_OS/os.configuring_&, which should be consulted if you
168e428f
PH
2238are porting Exim to a new operating system.
2239
2240
2241
f89d2485
PH
2242.section "Overriding build-time options for the monitor" "SECID31"
2243.cindex "building Eximon"
168e428f
PH
2244A similar process is used for overriding things when building the Exim monitor,
2245where the files that are involved are
9b371988
PH
2246.display
2247&_OS/eximon.conf-Default_&
2248&_OS/eximon.conf-_&<&'ostype'&>
2249&_Local/eximon.conf_&
2250&_Local/eximon.conf-_&<&'ostype'&>
2251&_Local/eximon.conf-_&<&'archtype'&>
2252&_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2253.endd
2254.cindex "&_Local/eximon.conf_&"
168e428f 2255As with Exim itself, the final three files need not exist, and in this case the
9b371988
PH
2256&_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2257&_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
168e428f
PH
2258variables of the same name, preceded by EXIMON_. For example, setting
2259EXIMON_LOG_DEPTH in the environment overrides the value of
2260LOG_DEPTH at run time.
4f578862 2261.ecindex IIDbuex
168e428f
PH
2262
2263
f89d2485 2264.section "Installing Exim binaries and scripts" "SECID32"
9b371988
PH
2265.cindex "installing Exim"
2266.cindex "BIN_DIRECTORY"
2267The command &`make install`& runs the &(exim_install)& script with no
2268arguments. The script copies binaries and utility scripts into the directory
2269whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2270.cindex "setuid" "installing Exim with"
068aaea8
PH
2271The install script copies files only if they are newer than the files they are
2272going to replace. The Exim binary is required to be owned by root and have the
9b371988
PH
2273&'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2274install`& as root so that it can set up the Exim binary in this way. However, in
068aaea8
PH
2275some special situations (for example, if a host is doing no local deliveries)
2276it may be possible to run Exim without making the binary setuid root (see
9b371988 2277chapter &<<CHAPsecurity>>& for details).
168e428f 2278
9b371988 2279.cindex "CONFIGURE_FILE"
168e428f 2280Exim's run time configuration file is named by the CONFIGURE_FILE setting
9b371988
PH
2281in &_Local/Makefile_&. If this names a single file, and the file does not
2282exist, the default configuration file &_src/configure.default_& is copied there
168e428f
PH
2283by the installation script. If a run time configuration file already exists, it
2284is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2285alternative files, no default is installed.
2286
9b371988
PH
2287.cindex "system aliases file"
2288.cindex "&_/etc/aliases_&"
168e428f
PH
2289One change is made to the default configuration file when it is installed: the
2290default configuration contains a router that references a system aliases file.
2291The path to this file is set to the value specified by
9b371988 2292SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
168e428f
PH
2293If the system aliases file does not exist, the installation script creates it,
2294and outputs a comment to the user.
2295
2296The created file contains no aliases, but it does contain comments about the
2297aliases a site should normally have. Mail aliases have traditionally been
9b371988
PH
2298kept in &_/etc/aliases_&. However, some operating systems are now using
2299&_/etc/mail/aliases_&. You should check if yours is one of these, and change
168e428f
PH
2300Exim's configuration if necessary.
2301
2302The default configuration uses the local host's name as the only local domain,
9b371988
PH
2303and is set up to do local deliveries into the shared directory &_/var/mail_&,
2304running as the local user. System aliases and &_.forward_& files in users' home
168e428f
PH
2305directories are supported, but no NIS or NIS+ support is configured. Domains
2306other than the name of the local host are routed using the DNS, with delivery
2307over SMTP.
2308
168e428f
PH
2309It is possible to install Exim for special purposes (such as building a binary
2310distribution) in a private part of the file system. You can do this by a
2311command such as
9b371988
PH
2312.code
2313make DESTDIR=/some/directory/ install
2314.endd
168e428f
PH
2315This has the effect of pre-pending the specified directory to all the file
2316paths, except the name of the system aliases file that appears in the default
9b371988 2317configuration. (If a default alias file is created, its name &'is'& modified.)
168e428f
PH
2318For backwards compatibility, ROOT is used if DESTDIR is not set,
2319but this usage is deprecated.
2320
9b371988
PH
2321.cindex "installing Exim" "what is not installed"
2322Running &'make install'& does not copy the Exim 4 conversion script
40df1be3
TF
2323&'convert4r4'&. You will probably run this only once if you are
2324upgrading from Exim 3. None of the documentation files in the &_doc_&
168e428f 2325directory are copied, except for the info files when you have set
9b371988 2326INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
168e428f 2327
9b371988 2328For the utility programs, old versions are renamed by adding the suffix &_.O_&
168e428f
PH
2329to their names. The Exim binary itself, however, is handled differently. It is
2330installed under a name that includes the version number and the compile number,
2aee48d6 2331for example &_exim-&version()-1_&. The script then arranges for a symbolic link
9b371988
PH
2332called &_exim_& to point to the binary. If you are updating a previous version
2333of Exim, the script takes care to ensure that the name &_exim_& is never absent
168e428f
PH
2334from the directory (as seen by other processes).
2335
9b371988
PH
2336.cindex "installing Exim" "testing the script"
2337If you want to see what the &'make install'& will do before running it for
2338real, you can pass the &%-n%& option to the installation script by this
2339command:
2340.code
2341make INSTALL_ARG=-n install
2342.endd
168e428f
PH
2343The contents of the variable INSTALL_ARG are passed to the installation
2344script. You do not need to be root to run this test. Alternatively, you can run
2345the installation script directly, but this must be from within the build
2346directory. For example, from the top-level Exim directory you could use this
2347command:
9b371988
PH
2348.code
2349(cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2350.endd
2351.cindex "installing Exim" "install script options"
168e428f
PH
2352There are two other options that can be supplied to the installation script.
2353
9b371988
PH
2354.ilist
2355&%-no_chown%& bypasses the call to change the owner of the installed binary
168e428f 2356to root, and the call to make it a setuid binary.
9b371988
PH
2357.next
2358&%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
168e428f 2359installed binary.
9b371988 2360.endlist
168e428f
PH
2361
2362INSTALL_ARG can be used to pass these options to the script. For example:
9b371988
PH
2363.code
2364make INSTALL_ARG=-no_symlink install
2365.endd
168e428f
PH
2366The installation script can also be given arguments specifying which files are
2367to be copied. For example, to install just the Exim binary, and nothing else,
2368without creating the symbolic link, you could use:
9b371988
PH
2369.code
2370make INSTALL_ARG='-no_symlink exim' install
2371.endd
168e428f
PH
2372
2373
2374
9b371988
PH
2375.section "Installing info documentation" "SECTinsinfdoc"
2376.cindex "installing Exim" "&'info'& documentation"
2377Not all systems use the GNU &'info'& system for documentation, and for this
168e428f
PH
2378reason, the Texinfo source of Exim's documentation is not included in the main
2379distribution. Instead it is available separately from the ftp site (see section
9b371988 2380&<<SECTavail>>&).
168e428f 2381
9b371988
PH
2382If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2383source of the documentation is found in the source tree, running &`make
2384install`& automatically builds the info files and installs them.
168e428f
PH
2385
2386
2387
f89d2485 2388.section "Setting up the spool directory" "SECID33"
9b371988 2389.cindex "spool directory" "creating"
168e428f
PH
2390When it starts up, Exim tries to create its spool directory if it does not
2391exist. The Exim uid and gid are used for the owner and group of the spool
2392directory. Sub-directories are automatically created in the spool directory as
2393necessary.
2394
2395
2396
2397
f89d2485 2398.section "Testing" "SECID34"
9b371988 2399.cindex "testing" "installation"
168e428f
PH
2400Having installed Exim, you can check that the run time configuration file is
2401syntactically valid by running the following command, which assumes that the
2402Exim binary directory is within your PATH environment variable:
9b371988
PH
2403.code
2404exim -bV
2405.endd
168e428f
PH
2406If there are any errors in the configuration file, Exim outputs error messages.
2407Otherwise it outputs the version number and build date,
2408the DBM library that is being used, and information about which drivers and
2409other optional code modules are included in the binary.
2410Some simple routing tests can be done by using the address testing option. For
2411example,
9b371988
PH
2412.display
2413&`exim -bt`& <&'local username'&>
2414.endd
168e428f 2415should verify that it recognizes a local mailbox, and
9b371988
PH
2416.display
2417&`exim -bt`& <&'remote address'&>
2418.endd
168e428f
PH
2419a remote one. Then try getting it to deliver mail, both locally and remotely.
2420This can be done by passing messages directly to Exim, without going through a
2421user agent. For example:
9b371988 2422.code
068aaea8
PH
2423exim -v postmaster@your.domain.example
2424From: user@your.domain.example
2425To: postmaster@your.domain.example
2426Subject: Testing Exim
168e428f 2427
068aaea8
PH
2428This is a test message.
2429^D
9b371988
PH
2430.endd
2431The &%-v%& option causes Exim to output some verification of what it is doing.
168e428f 2432In this case you should see copies of three log lines, one for the message's
9b371988 2433arrival, one for its delivery, and one containing &"Completed"&.
168e428f 2434
9b371988
PH
2435.cindex "delivery" "problems with"
2436If you encounter problems, look at Exim's log files (&'mainlog'& and
2437&'paniclog'&) to see if there is any relevant information there. Another source
168e428f 2438of information is running Exim with debugging turned on, by specifying the
9b371988 2439&%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
168e428f 2440with debugging turned on by a command of the form
9b371988
PH
2441.display
2442&`exim -d -M`& <&'exim-message-id'&>
2443.endd
2444You must be root or an &"admin user"& in order to do this. The &%-d%& option
168e428f 2445produces rather a lot of output, but you can cut this down to specific areas.
9b371988
PH
2446For example, if you use &%-d-all+route%& only the debugging information
2447relevant to routing is included. (See the &%-d%& option in chapter
2448&<<CHAPcommandline>>& for more details.)
168e428f 2449
9b371988
PH
2450.cindex '&"sticky"& bit'
2451.cindex "lock files"
168e428f
PH
2452One specific problem that has shown up on some sites is the inability to do
2453local deliveries into a shared mailbox directory, because it does not have the
9b371988 2454&"sticky bit"& set on it. By default, Exim tries to create a lock file before
168e428f 2455writing to a mailbox file, and if it cannot create the lock file, the delivery
9b371988 2456is deferred. You can get round this either by setting the &"sticky bit"& on the
168e428f
PH
2457directory, or by setting a specific group for local deliveries and allowing
2458that group to create files in the directory (see the comments above the
9b371988 2459&(local_delivery)& transport in the default configuration file). Another
168e428f 2460approach is to configure Exim not to use lock files, but just to rely on
9b371988
PH
2461&[fcntl()]& locking instead. However, you should do this only if all user
2462agents also use &[fcntl()]& locking. For further discussion of locking issues,
2463see chapter &<<CHAPappendfile>>&.
168e428f
PH
2464
2465One thing that cannot be tested on a system that is already running an MTA is
2466the receipt of incoming SMTP mail on the standard SMTP port. However, the
9b371988
PH
2467&%-oX%& option can be used to run an Exim daemon that listens on some other
2468port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2469&'exim_checkaccess'& utility can be used to check out policy controls on
168e428f
PH
2470incoming SMTP mail.
2471
2472Testing a new version on a system that is already running Exim can most easily
2473be done by building a binary with a different CONFIGURE_FILE setting. From
2474within the run time configuration, all other file and directory names
2475that Exim uses can be altered, in order to keep it entirely clear of the
2476production version.
2477
2478
f89d2485 2479.section "Replacing another MTA with Exim" "SECID35"
9b371988 2480.cindex "replacing another MTA"
168e428f
PH
2481Building and installing Exim for the first time does not of itself put it in
2482general use. The name by which the system's MTA is called by mail user agents
9b371988
PH
2483is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2484operating system), and it is necessary to make this name point to the &'exim'&
168e428f 2485binary in order to get the user agents to pass messages to Exim. This is
9b371988
PH
2486normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2487or &_/usr/lib/sendmail_&
2488.cindex "symbolic link" "to &'exim'& binary"
2489a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
168e428f
PH
2490privilege and executable status from the old MTA. It is then necessary to stop
2491and restart the mailer daemon, if one is running.
2492
f89d2485 2493.cindex "FreeBSD, MTA indirection"
9b371988 2494.cindex "&_/etc/mail/mailer.conf_&"
168e428f
PH
2495Some operating systems have introduced alternative ways of switching MTAs. For
2496example, if you are running FreeBSD, you need to edit the file
9b371988 2497&_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
168e428f
PH
2498described. A typical example of the contents of this file for running Exim is
2499as follows:
9b371988
PH
2500.code
2501sendmail /usr/exim/bin/exim
2502send-mail /usr/exim/bin/exim
2503mailq /usr/exim/bin/exim -bp
2504newaliases /usr/bin/true
2505.endd
2506Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2507your Exim installation is &"live"&. Check it by sending a message from your
168e428f
PH
2508favourite user agent.
2509
2510You should consider what to tell your users about the change of MTA. Exim may
2511have different capabilities to what was previously running, and there are
2512various operational differences such as the text of messages produced by
2513command line options and in bounce messages. If you allow your users to make
2514use of Exim's filtering capabilities, you should make the document entitled
9b371988 2515&'Exim's interface to mail filtering'& available to them.
168e428f
PH
2516
2517
2518
f89d2485 2519.section "Upgrading Exim" "SECID36"
9b371988 2520.cindex "upgrading Exim"
168e428f
PH
2521If you are already running Exim on your host, building and installing a new
2522version automatically makes it available to MUAs, or any other programs that
2523call the MTA directly. However, if you are running an Exim daemon, you do need
9b371988
PH
2524to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2525new binary. You do not need to stop processing mail in order to install a new
068aaea8
PH
2526version of Exim. The install script does not modify an existing runtime
2527configuration file.
2528
168e428f
PH
2529
2530
2531
f89d2485 2532.section "Stopping the Exim daemon on Solaris" "SECID37"
9b371988 2533.cindex "Solaris" "stopping Exim on"
168e428f 2534The standard command for stopping the mailer daemon on Solaris is
9b371988
PH
2535.code
2536/etc/init.d/sendmail stop
2537.endd
2538If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2539fails to stop Exim because it uses the command &'ps -e'& and greps the output
2540for the text &"sendmail"&; this is not present because the actual program name
2541(that is, &"exim"&) is given by the &'ps'& command with these options. A
2542solution is to replace the line that finds the process id with something like
2543.code
2544pid=`cat /var/spool/exim/exim-daemon.pid`
2545.endd
168e428f
PH
2546to obtain the daemon's pid directly from the file that Exim saves it in.
2547
9b371988 2548Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
168e428f
PH
2549still be received from local processes, and if automatic delivery is configured
2550(the normal case), deliveries will still occur.
2551
2552
2553
2554
9b371988
PH
2555. ////////////////////////////////////////////////////////////////////////////
2556. ////////////////////////////////////////////////////////////////////////////
168e428f 2557
9b371988 2558.chapter "The Exim command line" "CHAPcommandline"
4f578862
PH
2559.scindex IIDclo1 "command line" "options"
2560.scindex IIDclo2 "options" "command line"
168e428f
PH
2561Exim's command line takes the standard Unix form of a sequence of options,
2562each starting with a hyphen character, followed by a number of arguments. The
2563options are compatible with the main options of Sendmail, and there are also
2564some additional options, some of which are compatible with Smail 3. Certain
2565combinations of options do not make sense, and provoke an error if used.
2566The form of the arguments depends on which options are set.
2567
2568
f89d2485 2569.section "Setting options by program name" "SECID38"
9b371988
PH
2570.cindex "&'mailq'&"
2571If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
168e428f 2572were present before any other options.
9b371988 2573The &%-bp%& option requests a listing of the contents of the mail queue on the
168e428f
PH
2574standard output.
2575This feature is for compatibility with some systems that contain a command of
2576that name in one of the standard libraries, symbolically linked to
9b371988
PH
2577&_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2578
2579.cindex "&'rsmtp'&"
2580If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2581were present before any other options, for compatibility with Smail. The
2582&%-bS%& option is used for reading in a number of messages in batched SMTP
2583format.
2584
2585.cindex "&'rmail'&"
2586If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2587&%-oee%& options were present before any other options, for compatibility with
2588Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2589
2590.cindex "&'runq'&"
2591.cindex "queue runner"
2592If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2593were present before any other options, for compatibility with Smail. The &%-q%&
168e428f
PH
2594option causes a single queue runner process to be started.
2595
9b371988
PH
2596.cindex "&'newaliases'&"
2597.cindex "alias file" "building"
2598.cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2599If Exim is called under the name &'newaliases'& it behaves as if the option
2600&%-bi%& were present before any other options, for compatibility with Sendmail.
168e428f
PH
2601This option is used for rebuilding Sendmail's alias file. Exim does not have
2602the concept of a single alias file, but can be configured to run a given
9b371988 2603command if called with the &%-bi%& option.
168e428f
PH
2604
2605
9b371988
PH
2606.section "Trusted and admin users" "SECTtrustedadmin"
2607Some Exim options are available only to &'trusted users'& and others are
2608available only to &'admin users'&. In the description below, the phrases &"Exim
2609user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2610EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2611&%exim_group%& options. These do not necessarily have to use the name &"exim"&.
168e428f 2612
9b371988 2613.ilist
f89d2485 2614.cindex "trusted users" "definition of"
9b371988 2615.cindex "user" "trusted definition of"
168e428f 2616The trusted users are root, the Exim user, any user listed in the
9b371988
PH
2617&%trusted_users%& configuration option, and any user whose current group or any
2618supplementary group is one of those listed in the &%trusted_groups%&
168e428f 2619configuration option. Note that the Exim group is not automatically trusted.
9b371988
PH
2620
2621.cindex '&"From"& line'
2622.cindex "envelope sender"
2623Trusted users are always permitted to use the &%-f%& option or a leading
2624&"From&~"& line to specify the envelope sender of a message that is passed to
2625Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2626See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2627users to set envelope senders.
2628
2629.cindex "&'From:'& header line"
2630.cindex "&'Sender:'& header line"
1e4519cc
JH
2631.cindex "header lines" "From:"
2632.cindex "header lines" "Sender:"
9b371988
PH
2633For a trusted user, there is never any check on the contents of the &'From:'&
2634header line, and a &'Sender:'& line is never added. Furthermore, any existing
2635&'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2636
168e428f
PH
2637Trusted users may also specify a host name, host address, interface address,
2638protocol name, ident value, and authentication data when submitting a message
2639locally. Thus, they are able to insert messages into Exim's queue locally that
2640have the characteristics of messages received from a remote host. Untrusted
9b371988 2641users may in some circumstances use &%-f%&, but can never set the other values
168e428f 2642that are available to trusted users.
9b371988
PH
2643.next
2644.cindex "user" "admin definition of"
2645.cindex "admin user" "definition of"
168e428f 2646The admin users are root, the Exim user, and any user that is a member of the
9b371988 2647Exim group or of any group listed in the &%admin_groups%& configuration option.
168e428f 2648The current group does not have to be one of these groups.
9b371988 2649
168e428f
PH
2650Admin users are permitted to list the queue, and to carry out certain
2651operations on messages, for example, to force delivery failures. It is also
2652necessary to be an admin user in order to see the full information provided by
2653the Exim monitor, and full debugging output.
9b371988
PH
2654
2655By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2656Exim to attempt delivery of messages on its queue is restricted to admin users.
2657However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2658option false (that is, specifying &%no_prod_requires_admin%&).
2659
2660Similarly, the use of the &%-bp%& option to list all the messages in the queue
2661is restricted to admin users unless &%queue_list_requires_admin%& is set
168e428f 2662false.
9b371988 2663.endlist
168e428f
PH
2664
2665
9b371988 2666&*Warning*&: If you configure your system so that admin users are able to
168e428f
PH
2667edit Exim's configuration file, you are giving those users an easy way of
2668getting root. There is further discussion of this issue at the start of chapter
9b371988 2669&<<CHAPconf>>&.
168e428f
PH
2670
2671
2672
2673
f89d2485 2674.section "Command line options" "SECID39"
db9452a9
PH
2675Exim's command line options are described in alphabetical order below. If none
2676of the options that specifies a specific action (such as starting the daemon or
2677a queue runner, or testing an address, or receiving a message in a specific
2678format, or listing the queue) are present, and there is at least one argument
2679on the command line, &%-bm%& (accept a local message on the standard input,
2680with the arguments specifying the recipients) is assumed. Otherwise, Exim
2681outputs a brief message about itself and exits.
168e428f 2682
9b371988
PH
2683. ////////////////////////////////////////////////////////////////////////////
2684. Insert a stylized XML comment here, to identify the start of the command line
2685. options. This is for the benefit of the Perl script that automatically
2686. creates a man page for the options.
2687. ////////////////////////////////////////////////////////////////////////////
168e428f 2688
9b371988 2689.literal xml
168e428f 2690<!-- === Start of command line options === -->
9b371988 2691.literal off
168e428f
PH
2692
2693
9b371988
PH
2694.vlist
2695.vitem &%--%&
2696.oindex "--"
2697.cindex "options" "command line; terminating"
168e428f
PH
2698This is a pseudo-option whose only purpose is to terminate the options and
2699therefore to cause subsequent command line items to be treated as arguments
2700rather than options, even if they begin with hyphens.
2701
9b371988
PH
2702.vitem &%--help%&
2703.oindex "&%--help%&"
168e428f
PH
2704This option causes Exim to output a few sentences stating what it is.
2705The same output is generated if the Exim binary is called with no options and
2706no arguments.
2707
4b2241d2
PP
2708.vitem &%--version%&
2709.oindex "&%--version%&"
2710This option is an alias for &%-bV%& and causes version information to be
2711displayed.
2712
a3fb9793
PP
2713.vitem &%-Ac%& &&&
2714 &%-Am%&
2715.oindex "&%-Ac%&"
2716.oindex "&%-Am%&"
2717These options are used by Sendmail for selecting configuration files and are
2718ignored by Exim.
a3fb9793 2719
9b371988
PH
2720.vitem &%-B%&<&'type'&>
2721.oindex "&%-B%&"
2722.cindex "8-bit characters"
2723.cindex "Sendmail compatibility" "8-bit characters"
168e428f
PH
2724This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2725clean; it ignores this option.
2726
9b371988
PH
2727.vitem &%-bd%&
2728.oindex "&%-bd%&"
2729.cindex "daemon"
f89d2485 2730.cindex "SMTP" "listener"
9b371988 2731.cindex "queue runner"
168e428f 2732This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
9b371988
PH
2733the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2734that the daemon should also initiate periodic queue runs.
2735
2736The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2737(debugging) or &%-v%& (verifying) options are set, the daemon does not
168e428f
PH
2738disconnect from the controlling terminal. When running this way, it can be
2739stopped by pressing ctrl-C.
9b371988 2740
168e428f
PH
2741By default, Exim listens for incoming connections to the standard SMTP port on
2742all the host's running interfaces. However, it is possible to listen on other
2743ports, on multiple ports, and only on specific interfaces. Chapter
9b371988
PH
2744&<<CHAPinterfaces>>& contains a description of the options that control this.
2745
168e428f 2746When a listening daemon
9b371988
PH
2747.cindex "daemon" "process id (pid)"
2748.cindex "pid (process id)" "of daemon"
2749is started without the use of &%-oX%& (that is, without overriding the normal
2750configuration), it writes its process id to a file called &_exim-daemon.pid_&
2751in Exim's spool directory. This location can be overridden by setting
2752PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
168e428f 2753running as root.
9b371988
PH
2754
2755When &%-oX%& is used on the command line to start a listening daemon, the
2756process id is not written to the normal pid file path. However, &%-oP%& can be
168e428f 2757used to specify a path on the command line if a pid file is required.
9b371988 2758
168e428f 2759The SIGHUP signal
9b371988 2760.cindex "SIGHUP"
3cb1b51e
PH
2761.cindex "daemon" "restarting"
2762can be used to cause the daemon to re-execute itself. This should be done
2763whenever Exim's configuration file, or any file that is incorporated into it by
2764means of the &%.include%& facility, is changed, and also whenever a new version
2765of Exim is installed. It is not necessary to do this when other files that are
9b371988
PH
2766referenced from the configuration (for example, alias files) are changed,
2767because these are reread each time they are used.
2768
2769.vitem &%-bdf%&
2770.oindex "&%-bdf%&"
2771This option has the same effect as &%-bd%& except that it never disconnects
2772from the controlling terminal, even when no debugging is specified.
2773
2774.vitem &%-be%&
2775.oindex "&%-be%&"
2776.cindex "testing" "string expansion"
2777.cindex "expansion" "testing"
168e428f
PH
2778Run Exim in expansion testing mode. Exim discards its root privilege, to
2779prevent ordinary users from using this mode to read otherwise inaccessible
2780files. If no arguments are given, Exim runs interactively, prompting for lines
4f578862 2781of data. Otherwise, it processes each argument in turn.
9b371988
PH
2782
2783If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2784to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2785used without command line arguments. If successful, it uses the &[readline()]&
168e428f
PH
2786function, which provides extensive line-editing facilities, for reading the
2787test data. A line history is supported.
9b371988 2788
168e428f 2789Long expansion expressions can be split over several lines by using backslash
068aaea8 2790continuations. As in Exim's run time configuration, white space at the start of
168e428f
PH
2791continuation lines is ignored. Each argument or data line is passed through the
2792string expansion mechanism, and the result is output. Variable values from the
9b371988 2793configuration file (for example, &$qualify_domain$&) are available, but no
374dc194 2794message-specific values (such as &$message_exim_id$&) are set, because no message
f89d2485 2795is being processed (but see &%-bem%& and &%-Mset%&).
168e428f 2796
9b371988
PH
2797&*Note*&: If you use this mechanism to test lookups, and you change the data
2798files or databases you are using, you must exit and restart Exim before trying
2799the same lookup again. Otherwise, because each Exim process caches the results
2800of lookups, you will just get the same result as before.
9b371988 2801
3cb1b51e
PH
2802.vitem &%-bem%&&~<&'filename'&>
2803.oindex "&%-bem%&"
2804.cindex "testing" "string expansion"
2805.cindex "expansion" "testing"
2806This option operates like &%-be%& except that it must be followed by the name
2807of a file. For example:
2808.code
2809exim -bem /tmp/testmessage
2810.endd
2811The file is read as a message (as if receiving a locally-submitted non-SMTP
2812message) before any of the test expansions are done. Thus, message-specific
2813variables such as &$message_size$& and &$header_from:$& are available. However,
2814no &'Received:'& header is added to the message. If the &%-t%& option is set,
2815recipients are read from the headers in the normal way, and are shown in the
2816&$recipients$& variable. Note that recipients cannot be given on the command
2817line, because further arguments are taken as strings to expand (just like
2818&%-be%&).
3cb1b51e 2819
9b371988
PH
2820.vitem &%-bF%&&~<&'filename'&>
2821.oindex "&%-bF%&"
2822.cindex "system filter" "testing"
2823.cindex "testing" "system filter"
2824This option is the same as &%-bf%& except that it assumes that the filter being
168e428f
PH
2825tested is a system filter. The additional commands that are available only in
2826system filters are recognized.
2827
9b371988
PH
2828.vitem &%-bf%&&~<&'filename'&>
2829.oindex "&%-bf%&"
2830.cindex "filter" "testing"
2831.cindex "testing" "filter file"
2832.cindex "forward file" "testing"
2833.cindex "testing" "forward file"
2834.cindex "Sieve filter" "testing"
168e428f
PH
2835This option runs Exim in user filter testing mode; the file is the filter file
2836to be tested, and a test message must be supplied on the standard input. If
2837there are no message-dependent tests in the filter, an empty file can be
2838supplied.
168e428f 2839
9b371988
PH
2840If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2841can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2842filter and a user filter in the same run. For example:
2843.code
2844exim -bF /system/filter -bf /user/filter </test/message
2845.endd
168e428f
PH
2846This is helpful when the system filter adds header lines or sets filter
2847variables that are used by the user filter.
168e428f 2848
9b371988
PH
2849If the test filter file does not begin with one of the special lines
2850.code
2851# Exim filter
2852# Sieve filter
2853.endd
2854it is taken to be a normal &_.forward_& file, and is tested for validity under
2855that interpretation. See sections &<<SECTitenonfilred>>& to
2856&<<SECTspecitredli>>& for a description of the possible contents of non-filter
2857redirection lists.
2858
2859The result of an Exim command that uses &%-bf%&, provided no errors are
168e428f
PH
2860detected, is a list of the actions that Exim would try to take if presented
2861with the message for real. More details of filter testing are given in the
9b371988
PH
2862separate document entitled &'Exim's interfaces to mail filtering'&.
2863
168e428f 2864When testing a filter file,
9b371988
PH
2865.cindex "&""From""& line"
2866.cindex "envelope sender"
f89d2485 2867.oindex "&%-f%&" "for filter testing"
9b371988
PH
2868the envelope sender can be set by the &%-f%& option,
2869or by a &"From&~"& line at the start of the test message. Various parameters
2870that would normally be taken from the envelope recipient address of the message
2871can be set by means of additional command line options (see the next four
2872options).
2873
2874.vitem &%-bfd%&&~<&'domain'&>
2875.oindex "&%-bfd%&"
f89d2485 2876.vindex "&$qualify_domain$&"
168e428f 2877This sets the domain of the recipient address when a filter file is being
9b371988
PH
2878tested by means of the &%-bf%& option. The default is the value of
2879&$qualify_domain$&.
168e428f 2880
9b371988
PH
2881.vitem &%-bfl%&&~<&'local&~part'&>
2882.oindex "&%-bfl%&"
168e428f 2883This sets the local part of the recipient address when a filter file is being
9b371988 2884tested by means of the &%-bf%& option. The default is the username of the
168e428f
PH
2885process that calls Exim. A local part should be specified with any prefix or
2886suffix stripped, because that is how it appears to the filter when a message is
2887actually being delivered.
2888
9b371988
PH
2889.vitem &%-bfp%&&~<&'prefix'&>
2890.oindex "&%-bfp%&"
168e428f 2891This sets the prefix of the local part of the recipient address when a filter
9b371988 2892file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
PH
2893prefix.
2894
9b371988
PH
2895.vitem &%-bfs%&&~<&'suffix'&>
2896.oindex "&%-bfs%&"
168e428f 2897This sets the suffix of the local part of the recipient address when a filter
9b371988 2898file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
PH
2899suffix.
2900
9b371988
PH
2901.vitem &%-bh%&&~<&'IP&~address'&>
2902.oindex "&%-bh%&"
2903.cindex "testing" "incoming SMTP"
2904.cindex "SMTP" "testing incoming"
2905.cindex "testing" "relay control"
2906.cindex "relaying" "testing configuration"
2907.cindex "policy control" "testing"
2908.cindex "debugging" "&%-bh%& option"
168e428f
PH
2909This option runs a fake SMTP session as if from the given IP address, using the
2910standard input and output. The IP address may include a port number at the end,
2911after a full stop. For example:
9b371988
PH
2912.code
2913exim -bh 10.9.8.7.1234
2914exim -bh fe80::a00:20ff:fe86:a061.5678
2915.endd
168e428f 2916When an IPv6 address is given, it is converted into canonical form. In the case
9b371988
PH
2917of the second example above, the value of &$sender_host_address$& after
2918conversion to the canonical form is
2919&`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2920
168e428f 2921Comments as to what is going on are written to the standard error file. These
9b371988 2922include lines beginning with &"LOG"& for anything that would have been logged.
168e428f
PH
2923This facility is provided for testing configuration options for incoming
2924messages, to make sure they implement the required policy. For example, you can
9b371988
PH
2925test your relay controls using &%-bh%&.
2926
2927&*Warning 1*&:
2928.cindex "RFC 1413"
db9452a9
PH
2929You can test features of the configuration that rely on ident (RFC 1413)
2930information by using the &%-oMt%& option. However, Exim cannot actually perform
2931an ident callout when testing using &%-bh%& because there is no incoming SMTP
2932connection.
9b371988
PH
2933
2934&*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2935are also skipped when testing using &%-bh%&. If you want these callouts to
2936occur, use &%-bhc%& instead.
2937
168e428f
PH
2938Messages supplied during the testing session are discarded, and nothing is
2939written to any of the real log files. There may be pauses when DNS (and other)
9b371988 2940lookups are taking place, and of course these may time out. The &%-oMi%& option
db9452a9
PH
2941can be used to specify a specific IP interface and port if this is important,
2942and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2943session were authenticated.
9b371988
PH
2944
2945The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
168e428f 2946output just states whether a given recipient address from a given host is
9b371988 2947acceptable or not. See section &<<SECTcheckaccess>>&.
168e428f 2948
3cb1b51e 2949Features such as authentication and encryption, where the client input is not
f89d2485
PH
2950plain text, cannot easily be tested with &%-bh%&. Instead, you should use a
2951specialized SMTP test program such as
3cb1b51e 2952&url(http://jetmore.org/john/code/#swaks,swaks).
3cb1b51e 2953
9b371988
PH
2954.vitem &%-bhc%&&~<&'IP&~address'&>
2955.oindex "&%-bhc%&"
2956This option operates in the same way as &%-bh%&, except that address
168e428f
PH
2957verification callouts are performed if required. This includes consulting and
2958updating the callout cache database.
2959
9b371988
PH
2960.vitem &%-bi%&
2961.oindex "&%-bi%&"
2962.cindex "alias file" "building"
2963.cindex "building alias file"
2964.cindex "Sendmail compatibility" "&%-bi%& option"
2965Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
168e428f 2966Exim does not have the concept of a single alias file, and so it cannot mimic
9b371988 2967this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
168e428f
PH
2968tend to appear in various scripts such as NIS make files, so the option must be
2969recognized.
9b371988
PH
2970
2971If &%-bi%& is encountered, the command specified by the &%bi_command%&
168e428f 2972configuration option is run, under the uid and gid of the caller of Exim. If
9b371988
PH
2973the &%-oA%& option is used, its value is passed to the command as an argument.
2974The command set by &%bi_command%& may not contain arguments. The command can
2975use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2976if this is required. If the &%bi_command%& option is not set, calling Exim with
2977&%-bi%& is a no-op.
2978
36a3ae5f 2979. // Keep :help first, then the rest in alphabetical order
98a90c36
PP
2980.vitem &%-bI:help%&
2981.oindex "&%-bI:help%&"
2982.cindex "querying exim information"
2983We shall provide various options starting &`-bI:`& for querying Exim for
2984information. The output of many of these will be intended for machine
2985consumption. This one is not. The &%-bI:help%& option asks Exim for a
2986synopsis of supported options beginning &`-bI:`&. Use of any of these
2987options shall cause Exim to exit after producing the requested output.
2988
36a3ae5f
PP
2989.vitem &%-bI:dscp%&
2990.oindex "&%-bI:dscp%&"
2991.cindex "DSCP" "values"
2992This option causes Exim to emit an alphabetically sorted list of all
2993recognised DSCP names.
2994
98a90c36
PP
2995.vitem &%-bI:sieve%&
2996.oindex "&%-bI:sieve%&"
2997.cindex "Sieve filter" "capabilities"
2998This option causes Exim to emit an alphabetically sorted list of all supported
2999Sieve protocol extensions on stdout, one per line. This is anticipated to be
3000useful for ManageSieve (RFC 5804) implementations, in providing that protocol's
3001&`SIEVE`& capability response line. As the precise list may depend upon
3002compile-time build options, which this option will adapt to, this is the only
3003way to guarantee a correct response.
3004
9b371988
PH
3005.vitem &%-bm%&
3006.oindex "&%-bm%&"
3007.cindex "local message reception"
168e428f 3008This option runs an Exim receiving process that accepts an incoming,
a543079f 3009locally-generated message on the standard input. The recipients are given as the
9b371988 3010command arguments (except when &%-t%& is also present &-- see below). Each
168e428f
PH
3011argument can be a comma-separated list of RFC 2822 addresses. This is the
3012default option for selecting the overall action of an Exim call; it is assumed
3013if no other conflicting option is present.
9b371988 3014
168e428f 3015If any addresses in the message are unqualified (have no domain), they are
9b371988
PH
3016qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
3017options, as appropriate. The &%-bnq%& option (see below) provides a way of
168e428f 3018suppressing this for special cases.
9b371988 3019
168e428f 3020Policy checks on the contents of local messages can be enforced by means of
9b371988
PH
3021the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
3022
3023.cindex "return code" "for &%-bm%&"
3024The return code is zero if the message is successfully accepted. Otherwise, the
3025action is controlled by the &%-oe%&&'x'& option setting &-- see below.
3026
168e428f 3027The format
9b371988
PH
3028.cindex "message" "format"
3029.cindex "format" "message"
3030.cindex "&""From""& line"
3031.cindex "UUCP" "&""From""& line"
3032.cindex "Sendmail compatibility" "&""From""& line"
168e428f
PH
3033of the message must be as defined in RFC 2822, except that, for
3034compatibility with Sendmail and Smail, a line in one of the forms
9b371988
PH
3035.code
3036From sender Fri Jan 5 12:55 GMT 1997
3037From sender Fri, 5 Jan 97 12:55:01
3038.endd
168e428f
PH
3039(with the weekday optional, and possibly with additional text after the date)
3040is permitted to appear at the start of the message. There appears to be no
3041authoritative specification of the format of this line. Exim recognizes it by
9b371988 3042matching against the regular expression defined by the &%uucp_from_pattern%&
168e428f 3043option, which can be changed if necessary.
9b371988 3044
f89d2485
PH
3045.oindex "&%-f%&" "overriding &""From""& line"
3046The specified sender is treated as if it were given as the argument to the
9b371988 3047&%-f%& option, but if a &%-f%& option is also present, its argument is used in
168e428f
PH
3048preference to the address taken from the message. The caller of Exim must be a
3049trusted user for the sender of a message to be set in this way.
3050
5b257915
PP
3051.vitem &%-bmalware%&&~<&'filename'&>
3052.oindex "&%-bmalware%&"
3053.cindex "testing", "malware"
3054.cindex "malware scan test"
60f914bc
HSHR
3055This debugging option causes Exim to scan the given file or directory
3056(depending on the used scanner interface),
5b257915
PP
3057using the malware scanning framework. The option of &%av_scanner%& influences
3058this option, so if &%av_scanner%&'s value is dependent upon an expansion then
3059the expansion should have defaults which apply to this invocation. ACLs are