[exim.git] / doc / doc-docbook / spec.xfpt
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 printable 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.
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.
10 . /////////////////////////////////////////////////////////////////////////////
12 .include stdflags
13 .include stdmacs
15 . /////////////////////////////////////////////////////////////////////////////
16 . This outputs the standard DocBook boilerplate.
17 . /////////////////////////////////////////////////////////////////////////////
19 .docbook
21 . /////////////////////////////////////////////////////////////////////////////
22 . These lines are processing instructions for the Simple DocBook Processor that
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.
26 . /////////////////////////////////////////////////////////////////////////////
28 .literal xml
29 <?sdop
30 foot_right_recto="&chaptertitle; (&chapternumber;)"
31 foot_right_verso="&chaptertitle; (&chapternumber;)"
32 toc_chapter_blanks="yes,yes"
33 table_warn_overflow="overprint"
34 ?>
35 .literal off
37 . /////////////////////////////////////////////////////////////////////////////
38 . This generates the outermost <book> element that wraps the entire document.
39 . /////////////////////////////////////////////////////////////////////////////
41 .book
43 . /////////////////////////////////////////////////////////////////////////////
44 . These definitions set some parameters and save some typing.
45 . Update the Copyright year (only) when changing content.
46 . /////////////////////////////////////////////////////////////////////////////
48 .set previousversion "4.91"
49 .include ./local_params
51 .set ACL "access control lists (ACLs)"
52 .set I "&nbsp;&nbsp;&nbsp;&nbsp;"
54 .macro copyyear
55 2018
56 .endmacro
58 . /////////////////////////////////////////////////////////////////////////////
59 . Additional xfpt markup used by this document, over and above the default
60 . provided in the xfpt library.
61 . /////////////////////////////////////////////////////////////////////////////
63 . --- Override the &$ flag to automatically insert a $ with the variable name.
65 .flag &$ $& "<varname>$" "</varname>"
67 . --- Short flags for daggers in option headings. They will always be inside
68 . --- an italic string, but we want the daggers to be in Roman.
70 .flag &!! "</emphasis>&dagger;<emphasis>"
71 .flag &!? "</emphasis>&Dagger;<emphasis>"
73 . --- A macro for an Exim option definition heading, generating a one-line
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.
78 .macro option
79 .arg 5
80 .oindex "&%$5%&"
81 .endarg
82 .arg -5
83 .oindex "&%$1%&"
84 .endarg
85 .itable all 0 0 4 8* left 6* center 6* center 6* right
86 .row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&"
87 .endtable
88 .endmacro
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 . --- a small number of other 2-column tables override it.
94 .macro table2 196pt 254pt
95 .itable none 0 0 2 $1 left $2 left
96 .endmacro
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.
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
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.
121 .macro cindex
122 &<indexterm role="concept">&
123 &<primary>&$1&</primary>&
124 .arg 2
125 &<secondary>&$2&</secondary>&
126 .endarg
127 &</indexterm>&
128 .endmacro
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
139 .macro ecindex
140 &<indexterm role="concept" startref="$1" class="endofrange"/>&
141 .endmacro
143 .macro oindex
144 &<indexterm role="option">&
145 &<primary>&$1&</primary>&
146 .arg 2
147 &<secondary>&$2&</secondary>&
148 .endarg
149 &</indexterm>&
150 .endmacro
152 .macro vindex
153 &<indexterm role="variable">&
154 &<primary>&$1&</primary>&
155 .arg 2
156 &<secondary>&$2&</secondary>&
157 .endarg
158 &</indexterm>&
159 .endmacro
161 .macro index
162 .echo "** Don't use .index; use .cindex or .oindex or .vindex"
163 .endmacro
164 . ////////////////////////////////////////////////////////////////////////////
167 . ////////////////////////////////////////////////////////////////////////////
168 . The <bookinfo> element is removed from the XML before processing for ASCII
169 . output formats.
170 . ////////////////////////////////////////////////////////////////////////////
172 .literal xml
173 <bookinfo>
174 <title>Specification of the Exim Mail Transfer Agent</title>
175 <titleabbrev>The Exim MTA</titleabbrev>
176 <date>
177 .fulldate
178 </date>
179 <author><firstname>Exim</firstname><surname>Maintainers</surname></author>
180 <authorinitials>EM</authorinitials>
181 <revhistory><revision>
182 .versiondatexml
183 <authorinitials>EM</authorinitials>
184 </revision></revhistory>
185 <copyright><year>
186 .copyyear
187 </year><holder>University of Cambridge</holder></copyright>
188 </bookinfo>
189 .literal off
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 . /////////////////////////////////////////////////////////////////////////////
198 .chapter "Introduction" "CHID1"
199 .literal xml
201 <indexterm role="variable">
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">
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">
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>
262 <seealso><emphasis>limit</emphasis></seealso>
263 </indexterm>
264 <indexterm role="concept">
265 <primary>monitor</primary>
266 <see><emphasis>Exim monitor</emphasis></see>
267 </indexterm>
268 <indexterm role="concept">
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>
322 .literal off
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 . /////////////////////////////////////////////////////////////////////////////
331 Exim is a mail transfer agent (MTA) for hosts that are running Unix or
332 Unix-like operating systems. It was designed on the assumption that it would be
333 run on hosts that are permanently connected to the Internet. However, it can be
334 used on intermittently connected hosts with suitable configuration adjustments.
336 Configuration files currently exist for the following operating systems: AIX,
337 BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, Dragonfly, FreeBSD, GNU/Hurd,
338 GNU/Linux, HI-OSF (Hitachi), HI-UX, HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD,
339 OpenUNIX, QNX, SCO, SCO SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4,
340 Tru64-Unix (formerly Digital UNIX, formerly DEC-OSF1), Ultrix, and UnixWare.
341 Some of these operating systems are no longer current and cannot easily be
342 tested, so the configuration files may no longer work in practice.
344 There are also configuration files for compiling Exim in the Cygwin environment
345 that can be installed on systems running Windows. However, this document does
346 not contain any information about running Exim in the Cygwin environment.
348 The terms and conditions for the use and distribution of Exim are contained in
349 the file &_NOTICE_&. Exim is distributed under the terms of the GNU General
350 Public Licence, a copy of which may be found in the file &_LICENCE_&.
352 The use, supply, or promotion of Exim for the purpose of sending bulk,
353 unsolicited electronic mail is incompatible with the basic aims of Exim,
354 which revolve around the free provision of a service that enhances the quality
355 of personal communications. The author of Exim regards indiscriminate
356 mass-mailing as an antisocial, irresponsible abuse of the Internet.
358 Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
359 experience of running and working on the Smail 3 code, I could never have
360 contemplated starting to write a new MTA. Many of the ideas and user interfaces
361 were originally taken from Smail 3, though the actual code of Exim is entirely
362 new, and has developed far beyond the initial concept.
364 Many people, both in Cambridge and around the world, have contributed to the
365 development and the testing of Exim, and to porting it to various operating
366 systems. I am grateful to them all. The distribution now contains a file called
367 &_ACKNOWLEDGMENTS_&, in which I have started recording the names of
368 contributors.
371 .section "Exim documentation" "SECID1"
372 . Keep this example change bar when updating the documentation!
374 .new
375 .cindex "documentation"
376 This edition of the Exim specification applies to version &version() of Exim.
377 Substantive changes from the &previousversion; edition are marked in some
378 renditions of this document; this paragraph is so marked if the rendition is
379 capable of showing a change indicator.
380 .wen
382 This document is very much a reference manual; it is not a tutorial. The reader
383 is expected to have some familiarity with the SMTP mail transfer protocol and
384 with general Unix system administration. Although there are some discussions
385 and examples in places, the information is mostly organized in a way that makes
386 it easy to look up, rather than in a natural order for sequential reading.
387 Furthermore, this manual aims to cover every aspect of Exim in detail, including
388 a number of rarely-used, special-purpose features that are unlikely to be of
389 very wide interest.
391 .cindex "books about Exim"
392 An &"easier"& discussion of Exim which provides more in-depth explanatory,
393 introductory, and tutorial material can be found in a book entitled &'The Exim
394 SMTP Mail Server'& (second edition, 2007), published by UIT Cambridge
395 (&url(https://www.uit.co.uk/exim-book/)).
397 The book also contains a chapter that gives a general introduction to SMTP and
398 Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
399 with the latest release of Exim. (Note that the earlier book about Exim,
400 published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
402 .cindex "Debian" "information sources"
403 If you are using a Debian distribution of Exim, you will find information about
404 Debian-specific features in the file
405 &_/usr/share/doc/exim4-base/README.Debian_&.
406 The command &(man update-exim.conf)& is another source of Debian-specific
407 information.
409 .cindex "&_doc/NewStuff_&"
410 .cindex "&_doc/ChangeLog_&"
411 .cindex "change log"
412 As Exim develops, there may be features in newer versions that have not
413 yet made it into this document, which is updated only when the most significant
414 digit of the fractional part of the version number changes. Specifications of
415 new features that are not yet in this manual are placed in the file
416 &_doc/NewStuff_& in the Exim distribution.
418 Some features may be classified as &"experimental"&. These may change
419 incompatibly while they are developing, or even be withdrawn. For this reason,
420 they are not documented in this manual. Information about experimental features
421 can be found in the file &_doc/experimental.txt_&.
423 All changes to Exim (whether new features, bug fixes, or other kinds of
424 change) are noted briefly in the file called &_doc/ChangeLog_&.
426 .cindex "&_doc/spec.txt_&"
427 This specification itself is available as an ASCII file in &_doc/spec.txt_& so
428 that it can easily be searched with a text editor. Other files in the &_doc_&
429 directory are:
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"
437 .row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
438 .row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
439 .row &_openssl.txt_& "installing a current OpenSSL release"
440 .endtable
442 The main specification and the specification of the filtering language are also
443 available in other formats (HTML, PostScript, PDF, and Texinfo). Section
444 &<<SECTavail>>& below tells you how to get hold of these.
448 .section "FTP site and websites" "SECID2"
449 .cindex "website"
450 .cindex "FTP site"
451 The primary site for Exim source distributions is the &%exim.org%& FTP site,
452 available over HTTPS, HTTP and FTP. These services, and the &%exim.org%&
453 website, are hosted at the University of Cambridge.
455 .cindex "wiki"
456 .cindex "FAQ"
457 As well as Exim distribution tar files, the Exim website contains a number of
458 differently formatted versions of the documentation. A recent addition to the
459 online information is the Exim wiki (&url(https://wiki.exim.org)),
460 which contains what used to be a separate FAQ, as well as various other
461 examples, tips, and know-how that have been contributed by Exim users.
462 The wiki site should always redirect to the correct place, which is currently
463 provided by GitHub, and is open to editing by anyone with a GitHub account.
465 .cindex Bugzilla
466 An Exim Bugzilla exists at &url(https://bugs.exim.org). You can use
467 this to report bugs, and also to add items to the wish list. Please search
468 first to check that you are not duplicating a previous entry.
469 Please do not ask for configuration help in the bug-tracker.
472 .section "Mailing lists" "SECID3"
473 .cindex "mailing lists" "for Exim users"
474 The following Exim mailing lists exist:
476 .table2 140pt
477 .row &'exim-announce@exim.org'& "Moderated, low volume announcements list"
478 .row &'exim-users@exim.org'& "General discussion list"
479 .row &'exim-dev@exim.org'& "Discussion of bugs, enhancements, etc."
480 .row &'exim-cvs@exim.org'& "Automated commit messages from the VCS"
481 .endtable
483 You can subscribe to these lists, change your existing subscriptions, and view
484 or search the archives via the mailing lists link on the Exim home page.
485 .cindex "Debian" "mailing list for"
486 If you are using a Debian distribution of Exim, you may wish to subscribe to
487 the Debian-specific mailing list &'pkg-exim4-users@lists.alioth.debian.org'&
488 via this web page:
489 .display
490 &url(https://alioth-lists.debian.net/cgi-bin/mailman/listinfo/pkg-exim4-users)
491 .endd
492 Please ask Debian-specific questions on that list and not on the general Exim
493 lists.
495 .section "Bug reports" "SECID5"
496 .cindex "bug reports"
497 .cindex "reporting bugs"
498 Reports of obvious bugs can be emailed to &'bugs@exim.org'& or reported
499 via the Bugzilla (&url(https://bugs.exim.org)). However, if you are unsure
500 whether some behaviour is a bug or not, the best thing to do is to post a
501 message to the &'exim-dev'& mailing list and have it discussed.
505 .section "Where to find the Exim distribution" "SECTavail"
506 .cindex "FTP site"
507 .cindex "HTTPS download site"
508 .cindex "distribution" "FTP site"
509 .cindex "distribution" "https site"
510 The master distribution site for the Exim distribution is
511 .display
512 &url(https://downloads.exim.org/)
513 .endd
514 The service is available over HTTPS, HTTP and FTP.
515 We encourage people to migrate to HTTPS.
517 The content served at &url(https://downloads.exim.org/) is identical to the
518 content served at &url(https://ftp.exim.org/pub/exim) and
519 &url(ftp://ftp.exim.org/pub/exim).
521 If accessing via a hostname containing &'ftp'&, then the file references that
522 follow are relative to the &_exim_& directories at these sites.
523 If accessing via the hostname &'downloads'& then the subdirectories described
524 here are top-level directories.
526 There are now quite a number of independent mirror sites around
527 the world. Those that I know about are listed in the file called &_Mirrors_&.
529 Within the top exim directory there are subdirectories called &_exim3_& (for
530 previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
531 distributions), and &_Testing_& for testing versions. In the &_exim4_&
532 subdirectory, the current release can always be found in files called
533 .display
534 &_exim-n.nn.tar.xz_&
535 &_exim-n.nn.tar.gz_&
536 &_exim-n.nn.tar.bz2_&
537 .endd
538 where &'n.nn'& is the highest such version number in the directory. The three
539 files contain identical data; the only difference is the type of compression.
540 The &_.xz_& file is usually the smallest, while the &_.gz_& file is the
541 most portable to old systems.
543 .cindex "distribution" "signing details"
544 .cindex "distribution" "public key"
545 .cindex "public key for signed distribution"
546 The distributions will be PGP signed by an individual key of the Release
547 Coordinator. This key will have a uid containing an email address in the
548 &'exim.org'& domain and will have signatures from other people, including
549 other Exim maintainers. We expect that the key will be in the "strong set" of
550 PGP keys. There should be a trust path to that key from the Exim Maintainer's
551 PGP keys, a version of which can be found in the release directory in the file
552 &_Exim-Maintainers-Keyring.asc_&. All keys used will be available in public keyserver pools,
553 such as &'pool.sks-keyservers.net'&.
555 At the time of the last update, releases were being made by Jeremy Harris and signed
556 with key &'0xBCE58C8CE41F32DF'&. Other recent keys used for signing are those
557 of Heiko Schlittermann, &'0x26101B62F69376CE'&,
558 and of Phil Pennock, &'0x4D1E900E14C1CC04'&.
560 The signatures for the tar bundles are in:
561 .display
562 &_exim-n.nn.tar.xz.asc_&
563 &_exim-n.nn.tar.gz.asc_&
564 &_exim-n.nn.tar.bz2.asc_&
565 .endd
566 For each released version, the log of changes is made available in a
567 separate file in the directory &_ChangeLogs_& so that it is possible to
568 find out what has changed without having to download the entire distribution.
570 .cindex "documentation" "available formats"
571 The main distribution contains ASCII versions of this specification and other
572 documentation; other formats of the documents are available in separate files
573 inside 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
580 These tar files contain only the &_doc_& directory, not the complete
581 distribution, and are also available in &_.bz2_& and &_.xz_& forms.
584 .section "Limitations" "SECID6"
585 .ilist
586 .cindex "limitations of Exim"
587 .cindex "bang paths" "not handled by Exim"
588 Exim is designed for use as an Internet MTA, and therefore handles addresses in
589 RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
590 simple two-component bang paths can be converted by a straightforward rewriting
591 configuration. This restriction does not prevent Exim from being interfaced to
592 UUCP as a transport mechanism, provided that domain addresses are used.
593 .next
594 .cindex "domainless addresses"
595 .cindex "address" "without domain"
596 Exim insists that every address it handles has a domain attached. For incoming
597 local messages, domainless addresses are automatically qualified with a
598 configured domain value. Configuration options specify from which remote
599 systems unqualified addresses are acceptable. These are then qualified on
600 arrival.
601 .next
602 .cindex "transport" "external"
603 .cindex "external transports"
604 The only external transport mechanisms that are currently implemented are SMTP
605 and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
606 transport is available, and there are facilities for writing messages to files
607 and pipes, optionally in &'batched SMTP'& format; these facilities can be used
608 to send messages to other transport mechanisms such as UUCP, provided they can
609 handle domain-style addresses. Batched SMTP input is also catered for.
610 .next
611 Exim is not designed for storing mail for dial-in hosts. When the volumes of
612 such mail are large, it is better to get the messages &"delivered"& into files
613 (that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
614 other means.
615 .next
616 Although Exim does have basic facilities for scanning incoming messages, these
617 are not comprehensive enough to do full virus or spam scanning. Such operations
618 are best carried out using additional specialized software packages. If you
619 compile Exim with the content-scanning extension, straightforward interfaces to
620 a number of common scanners are provided.
621 .endlist
624 .section "Runtime configuration" "SECID7"
625 Exim's runtime configuration is held in a single text file that is divided
626 into a number of sections. The entries in this file consist of keywords and
627 values, in the style of Smail 3 configuration files. A default configuration
628 file which is suitable for simple online installations is provided in the
629 distribution, and is described in chapter &<<CHAPdefconfil>>& below.
632 .section "Calling interface" "SECID8"
633 .cindex "Sendmail compatibility" "command line interface"
634 Like many MTAs, Exim has adopted the Sendmail command line interface so that it
635 can be a straight replacement for &_/usr/lib/sendmail_& or
636 &_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
637 about Sendmail in order to run Exim. For actions other than sending messages,
638 Sendmail-compatible options also exist, but those that produce output (for
639 example, &%-bp%&, which lists the messages in the queue) do so in Exim's own
640 format. There are also some additional options that are compatible with Smail
641 3, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
642 documents all Exim's command line options. This information is automatically
643 made into the man page that forms part of the Exim distribution.
645 Control of messages in the queue can be done via certain privileged command
646 line options. There is also an optional monitor program called &'eximon'&,
647 which displays current information in an X window, and which contains a menu
648 interface to Exim's command line administration options.
652 .section "Terminology" "SECID9"
653 .cindex "terminology definitions"
654 .cindex "body of message" "definition of"
655 The &'body'& of a message is the actual data that the sender wants to transmit.
656 It is the last part of a message and is separated from the &'header'& (see
657 below) by a blank line.
659 .cindex "bounce message" "definition of"
660 When a message cannot be delivered, it is normally returned to the sender in a
661 delivery failure message or a &"non-delivery report"& (NDR). The term
662 &'bounce'& is commonly used for this action, and the error reports are often
663 called &'bounce messages'&. This is a convenient shorthand for &"delivery
664 failure error report"&. Such messages have an empty sender address in the
665 message's &'envelope'& (see below) to ensure that they cannot themselves give
666 rise to further bounce messages.
668 The term &'default'& appears frequently in this manual. It is used to qualify a
669 value which is used in the absence of any setting in the configuration. It may
670 also qualify an action which is taken unless a configuration setting specifies
671 otherwise.
673 The term &'defer'& is used when the delivery of a message to a specific
674 destination cannot immediately take place for some reason (a remote host may be
675 down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
676 until a later time.
678 The word &'domain'& is sometimes used to mean all but the first component of a
679 host's name. It is &'not'& used in that sense here, where it normally refers to
680 the part of an email address following the @ sign.
682 .cindex "envelope, definition of"
683 .cindex "sender" "definition of"
684 A message in transit has an associated &'envelope'&, as well as a header and a
685 body. The envelope contains a sender address (to which bounce messages should
686 be delivered), and any number of recipient addresses. References to the
687 sender or the recipients of a message usually mean the addresses in the
688 envelope. An MTA uses these addresses for delivery, and for returning bounce
689 messages, not the addresses that appear in the header lines.
691 .cindex "message" "header, definition of"
692 .cindex "header section" "definition of"
693 The &'header'& of a message is the first part of a message's text, consisting
694 of 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
696 indenting the continuations. The header is separated from the body by a blank
697 line.
699 .cindex "local part" "definition of"
700 .cindex "domain" "definition of"
701 The term &'local part'&, which is taken from RFC 2822, is used to refer to the
702 part of an email address that precedes the @ sign. The part that follows the
703 @ sign is called the &'domain'& or &'mail domain'&.
705 .cindex "local delivery" "definition of"
706 .cindex "remote delivery, definition of"
707 The terms &'local delivery'& and &'remote delivery'& are used to distinguish
708 delivery to a file or a pipe on the local host from delivery by SMTP over
709 TCP/IP to another host. As far as Exim is concerned, all hosts other than the
710 host it is running on are &'remote'&.
712 .cindex "return path" "definition of"
713 &'Return path'& is another name that is used for the sender address in a
714 message's envelope.
716 .cindex "queue" "definition of"
717 The term &'queue'& is used to refer to the set of messages awaiting delivery
718 because this term is in widespread use in the context of MTAs. However, in
719 Exim's case, the reality is more like a pool than a queue, because there is
720 normally no ordering of waiting messages.
722 .cindex "queue runner" "definition of"
723 The term &'queue runner'& is used to describe a process that scans the queue
724 and attempts to deliver those messages whose retry times have come. This term
725 is used by other MTAs and also relates to the command &%runq%&, but in Exim
726 the waiting messages are normally processed in an unpredictable order.
728 .cindex "spool directory" "definition of"
729 The term &'spool directory'& is used for a directory in which Exim keeps the
730 messages in its queue &-- that is, those that it is in the process of
731 delivering. This should not be confused with the directory in which local
732 mailboxes are stored, which is called a &"spool directory"& by some people. In
733 the Exim documentation, &"spool"& is always used in the first sense.
740 . ////////////////////////////////////////////////////////////////////////////
741 . ////////////////////////////////////////////////////////////////////////////
743 .chapter "Incorporated code" "CHID2"
744 .cindex "incorporated code"
745 .cindex "regular expressions" "library"
746 .cindex "PCRE"
747 .cindex "OpenDMARC"
748 A number of pieces of external code are included in the Exim distribution.
750 .ilist
751 Regular expressions are supported in the main Exim program and in the
752 Exim monitor using the freely-distributable PCRE library, copyright
753 &copy; University of Cambridge. The source to PCRE is no longer shipped with
754 Exim, so you will need to use the version of PCRE shipped with your system,
755 or obtain and install the full version of the library from
756 &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
757 .next
758 .cindex "cdb" "acknowledgment"
759 Support for the cdb (Constant DataBase) lookup method is provided by code
760 contributed by Nigel Metheringham of (at the time he contributed it) Planet
761 Online Ltd. The implementation is completely contained within the code of Exim.
762 It does not link against an external cdb library. The code contains the
763 following statements:
765 .blockquote
766 Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
768 This program is free software; you can redistribute it and/or modify it under
769 the terms of the GNU General Public License as published by the Free Software
770 Foundation; either version 2 of the License, or (at your option) any later
771 version.
772 This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
773 the spec and sample code for cdb can be obtained from
774 &url(https://cr.yp.to/cdb.html). This implementation borrows
775 some code from Dan Bernstein's implementation (which has no license
776 restrictions applied to it).
777 .endblockquote
778 .next
779 .cindex "SPA authentication"
780 .cindex "Samba project"
781 .cindex "Microsoft Secure Password Authentication"
782 Client support for Microsoft's &'Secure Password Authentication'& is provided
783 by code contributed by Marc Prud'hommeaux. Server support was contributed by
784 Tom Kistner. This includes code taken from the Samba project, which is released
785 under the Gnu GPL.
786 .next
787 .cindex "Cyrus"
788 .cindex "&'pwcheck'& daemon"
789 .cindex "&'pwauthd'& daemon"
790 Support for calling the Cyrus &'pwcheck'& and &'saslauthd'& daemons is provided
791 by code taken from the Cyrus-SASL library and adapted by Alexander S.
792 Sabourenkov. The permission notice appears below, in accordance with the
793 conditions expressed therein.
795 .blockquote
796 Copyright &copy; 2001 Carnegie Mellon University. All rights reserved.
798 Redistribution and use in source and binary forms, with or without
799 modification, are permitted provided that the following conditions
800 are met:
802 .olist
803 Redistributions of source code must retain the above copyright
804 notice, this list of conditions and the following disclaimer.
805 .next
806 Redistributions in binary form must reproduce the above copyright
807 notice, this list of conditions and the following disclaimer in
808 the documentation and/or other materials provided with the
809 distribution.
810 .next
811 The name &"Carnegie Mellon University"& must not be used to
812 endorse or promote products derived from this software without
813 prior written permission. For permission or any other legal
814 details, please contact
815 .display
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
822 .endd
823 .next
824 Redistributions of any form whatsoever must retain the following
825 acknowledgment:
827 &"This product includes software developed by Computing Services
828 at Carnegie Mellon University (&url(https://www.cmu.edu/computing/)."&
837 .endlist
838 .endblockquote
840 .next
841 .cindex "Exim monitor" "acknowledgment"
842 .cindex "X-windows"
843 .cindex "Athena"
844 The Exim Monitor program, which is an X-Window application, includes
845 modified versions of the Athena StripChart and TextPop widgets.
846 This code is copyright by DEC and MIT, and their permission notice appears
847 below, in accordance with the conditions expressed therein.
849 .blockquote
850 Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
851 and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
853 All Rights Reserved
855 Permission to use, copy, modify, and distribute this software and its
856 documentation for any purpose and without fee is hereby granted,
857 provided that the above copyright notice appear in all copies and that
858 both that copyright notice and this permission notice appear in
859 supporting documentation, and that the names of Digital or MIT not be
860 used in advertising or publicity pertaining to distribution of the
861 software without specific, written prior permission.
870 .endblockquote
872 .next
873 .cindex "opendmarc" "acknowledgment"
874 The DMARC implementation uses the OpenDMARC library which is Copyrighted by
875 The Trusted Domain Project. Portions of Exim source which use OpenDMARC
876 derived code are indicated in the respective source files. The full OpenDMARC
877 license is provided in the LICENSE.opendmarc file contained in the distributed
878 source code.
880 .next
881 Many people have contributed code fragments, some large, some small, that were
882 not covered by any specific license requirements. It is assumed that the
883 contributors are happy to see their code incorporated into Exim under the GPL.
884 .endlist
890 . ////////////////////////////////////////////////////////////////////////////
891 . ////////////////////////////////////////////////////////////////////////////
893 .chapter "How Exim receives and delivers mail" "CHID11" &&&
894 "Receiving and delivering mail"
897 .section "Overall philosophy" "SECID10"
898 .cindex "design philosophy"
899 Exim is designed to work efficiently on systems that are permanently connected
900 to the Internet and are handling a general mix of mail. In such circumstances,
901 most messages can be delivered immediately. Consequently, Exim does not
902 maintain independent queues of messages for specific domains or hosts, though
903 it does try to send several messages in a single SMTP connection after a host
904 has been down, and it also maintains per-host retry information.
907 .section "Policy control" "SECID11"
908 .cindex "policy control" "overview"
909 Policy controls are now an important feature of MTAs that are connected to the
910 Internet. Perhaps their most important job is to stop MTAs from being abused as
911 &"open relays"& by misguided individuals who send out vast amounts of
912 unsolicited junk and want to disguise its source. Exim provides flexible
913 facilities for specifying policy controls on incoming mail:
915 .ilist
916 .cindex "&ACL;" "introduction"
917 Exim 4 (unlike previous versions of Exim) implements policy controls on
918 incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
919 series of statements that may either grant or deny access. ACLs can be used at
920 several places in the SMTP dialogue while receiving a message from a remote
921 host. However, the most common places are after each RCPT command, and at the
922 very end of the message. The sysadmin can specify conditions for accepting or
923 rejecting individual recipients or the entire message, respectively, at these
924 two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
925 error code.
926 .next
927 An ACL is also available for locally generated, non-SMTP messages. In this
928 case, the only available actions are to accept or deny the entire message.
929 .next
930 When Exim is compiled with the content-scanning extension, facilities are
931 provided in the ACL mechanism for passing the message to external virus and/or
932 spam scanning software. The result of such a scan is passed back to the ACL,
933 which can then use it to decide what to do with the message.
934 .next
935 When a message has been received, either from a remote host or from the local
936 host, but before the final acknowledgment has been sent, a locally supplied C
937 function called &[local_scan()]& can be run to inspect the message and decide
938 whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
939 is accepted, the list of recipients can be modified by the function.
940 .next
941 Using the &[local_scan()]& mechanism is another way of calling external scanner
942 software. The &%SA-Exim%& add-on package works this way. It does not require
943 Exim to be compiled with the content-scanning extension.
944 .next
945 After a message has been accepted, a further checking mechanism is available in
946 the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
947 runs at the start of every delivery process.
948 .endlist
952 .section "User filters" "SECID12"
953 .cindex "filter" "introduction"
954 .cindex "Sieve filter"
955 In a conventional Exim configuration, users are able to run private filters by
956 setting up appropriate &_.forward_& files in their home directories. See
957 chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
958 configuration needed to support this, and the separate document entitled
959 &'Exim's interfaces to mail filtering'& for user details. Two different kinds
960 of filtering are available:
962 .ilist
963 Sieve filters are written in the standard filtering language that is defined
964 by RFC 3028.
965 .next
966 Exim filters are written in a syntax that is unique to Exim, but which is more
967 powerful than Sieve, which it pre-dates.
968 .endlist
970 User filters are run as part of the routing process, described below.
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"
982 Every message handled by Exim is given a &'message id'& which is sixteen
983 characters long. It is divided into three parts, separated by hyphens, for
984 example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
985 normally encoding numbers in base 62. However, in the Darwin operating
986 system (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
988 id is used to construct filenames, and the names of files in those systems are
989 not always case-sensitive.
991 .cindex "pid (process id)" "re-use of"
992 The detail of the contents of the message id have changed as Exim has evolved.
993 Earlier versions relied on the operating system not re-using a process id (pid)
994 within one second. On modern operating systems, this assumption can no longer
995 be made, so the algorithm had to be changed. To retain backward compatibility,
996 the format of the message id was retained, which is why the following rules are
997 somewhat eccentric:
999 .ilist
1000 The first six characters of the message id are the time at which the message
1001 started to be received, to a granularity of one second. That is, this field
1002 contains the number of seconds since the start of the epoch (the normal Unix
1003 way of representing the date and time of day).
1004 .next
1005 After the first hyphen, the next six characters are the id of the process that
1006 received the message.
1007 .next
1008 There are two different possibilities for the final two characters:
1009 .olist
1010 .oindex "&%localhost_number%&"
1011 If &%localhost_number%& is not set, this value is the fractional part of the
1012 time of reception, normally in units of 1/2000 of a second, but for systems
1013 that must use base 36 instead of base 62 (because of case-insensitive file
1014 systems), the units are 1/1000 of a second.
1015 .next
1016 If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
1017 the fractional part of the time, which in this case is in units of 1/200
1018 (1/100) of a second.
1019 .endlist
1020 .endlist
1022 After a message has been received, Exim waits for the clock to tick at the
1023 appropriate resolution before proceeding, so that if another message is
1024 received by the same process, or by another process with the same (re-used)
1025 pid, it is guaranteed that the time will be different. In most cases, the clock
1026 will already have ticked while the message was being received.
1029 .section "Receiving mail" "SECID13"
1030 .cindex "receiving mail"
1031 .cindex "message" "reception"
1032 The only way Exim can receive mail from another host is using SMTP over
1033 TCP/IP, in which case the sender and recipient addresses are transferred using
1034 SMTP commands. However, from a locally running process (such as a user's MUA),
1035 there are several possibilities:
1037 .ilist
1038 If the process runs Exim with the &%-bm%& option, the message is read
1039 non-interactively (usually via a pipe), with the recipients taken from the
1040 command line, or from the body of the message if &%-t%& is also used.
1041 .next
1042 If the process runs Exim with the &%-bS%& option, the message is also read
1043 non-interactively, but in this case the recipients are listed at the start of
1044 the message in a series of SMTP RCPT commands, terminated by a DATA
1045 command. This is called &"batch SMTP"& format,
1046 but it isn't really SMTP. The SMTP commands are just another way of passing
1047 envelope addresses in a non-interactive submission.
1048 .next
1049 If the process runs Exim with the &%-bs%& option, the message is read
1050 interactively, using the SMTP protocol. A two-way pipe is normally used for
1051 passing data between the local process and the Exim process.
1052 This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
1053 example, the ACLs for SMTP commands are used for this form of submission.
1054 .next
1055 A local process may also make a TCP/IP call to the host's loopback address
1056 ( or any other of its IP addresses. When receiving messages, Exim
1057 does not treat the loopback address specially. It treats all such connections
1058 in the same way as connections from other hosts.
1059 .endlist
1062 .cindex "message sender, constructed by Exim"
1063 .cindex "sender" "constructed by Exim"
1064 In the three cases that do not involve TCP/IP, the sender address is
1065 constructed from the login name of the user that called Exim and a default
1066 qualification domain (which can be set by the &%qualify_domain%& configuration
1067 option). For local or batch SMTP, a sender address that is passed using the
1068 SMTP MAIL command is ignored. However, the system administrator may allow
1069 certain users (&"trusted users"&) to specify a different sender addresses
1070 unconditionally, or all users to specify certain forms of different sender
1071 address. The &%-f%& option or the SMTP MAIL command is used to specify these
1072 different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1073 users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
1074 users to change sender addresses.
1076 Messages received by either of the non-interactive mechanisms are subject to
1077 checking 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
1079 number of ACLs that operate at different times during the SMTP session. Either
1080 individual recipients or the entire message can be rejected if local policy
1081 requirements are not met. The &[local_scan()]& function (see chapter
1082 &<<CHAPlocalscan>>&) is run for all incoming messages.
1084 Exim can be configured not to start a delivery process when a message is
1085 received; this can be unconditional, or depend on the number of incoming SMTP
1086 connections or the system load. In these situations, new messages wait on the
1087 queue until a queue runner process picks them up. However, in standard
1088 configurations under normal conditions, delivery is started as soon as a
1089 message is received.
1095 .section "Handling an incoming message" "SECID14"
1096 .cindex "spool directory" "files that hold a message"
1097 .cindex "file" "how a message is held"
1098 When Exim accepts a message, it writes two files in its spool directory. The
1099 first contains the envelope information, the current status of the message, and
1100 the header lines, and the second contains the body of the message. The names of
1101 the two spool files consist of the message id, followed by &`-H`& for the
1102 file containing the envelope and header, and &`-D`& for the data file.
1104 .cindex "spool directory" "&_input_& sub-directory"
1105 By default, all these message files are held in a single directory called
1106 &_input_& inside the general Exim spool directory. Some operating systems do
1107 not perform very well if the number of files in a directory gets large; to
1108 improve performance in such cases, the &%split_spool_directory%& option can be
1109 used. This causes Exim to split up the input files into 62 sub-directories
1110 whose names are single letters or digits. When this is done, the queue is
1111 processed one sub-directory at a time instead of all at once, which can improve
1112 overall performance even when there are not enough files in each directory to
1113 affect file system performance.
1115 The envelope information consists of the address of the message's sender and
1116 the addresses of the recipients. This information is entirely separate from
1117 any addresses contained in the header lines. The status of the message includes
1118 a list of recipients who have already received the message. The format of the
1119 first spool file is described in chapter &<<CHAPspool>>&.
1121 .cindex "rewriting" "addresses"
1122 Address rewriting that is specified in the rewrite section of the configuration
1123 (see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
1124 both in the header lines and the envelope, at the time the message is accepted.
1125 If during the course of delivery additional addresses are generated (for
1126 example, via aliasing), these new addresses are rewritten as soon as they are
1127 generated. At the time a message is actually delivered (transported) further
1128 rewriting can take place; because this is a transport option, it can be
1129 different for different forms of delivery. It is also possible to specify the
1130 addition or removal of certain header lines at the time the message is
1131 delivered (see chapters &<<CHAProutergeneric>>& and
1132 &<<CHAPtransportgeneric>>&).
1136 .section "Life of a message" "SECID15"
1137 .cindex "message" "life of"
1138 .cindex "message" "frozen"
1139 A message remains in the spool directory until it is completely delivered to
1140 its recipients or to an error address, or until it is deleted by an
1141 administrator or by the user who originally created it. In cases when delivery
1142 cannot proceed &-- for example when a message can neither be delivered to its
1143 recipients nor returned to its sender, the message is marked &"frozen"& on the
1144 spool, and no more deliveries are attempted.
1146 .cindex "frozen messages" "thawing"
1147 .cindex "message" "thawing frozen"
1148 An administrator can &"thaw"& such messages when the problem has been
1149 corrected, and can also freeze individual messages by hand if necessary. In
1150 addition, an administrator can force a delivery error, causing a bounce message
1151 to be sent.
1153 .oindex "&%timeout_frozen_after%&"
1154 .oindex "&%ignore_bounce_errors_after%&"
1155 There are options called &%ignore_bounce_errors_after%& and
1156 &%timeout_frozen_after%&, which discard frozen messages after a certain time.
1157 The first applies only to frozen bounces, the second to all frozen messages.
1159 .cindex "message" "log file for"
1160 .cindex "log" "file for each message"
1161 While Exim is working on a message, it writes information about each delivery
1162 attempt to its main log file. This includes successful, unsuccessful, and
1163 delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1164 lines are also written to a separate &'message log'& file for each message.
1165 These logs are solely for the benefit of the administrator and are normally
1166 deleted along with the spool files when processing of a message is complete.
1167 The use of individual message logs can be disabled by setting
1168 &%no_message_logs%&; this might give an improvement in performance on very busy
1169 systems.
1171 .cindex "journal file"
1172 .cindex "file" "journal"
1173 All the information Exim itself needs to set up a delivery is kept in the first
1174 spool file, along with the header lines. When a successful delivery occurs, the
1175 address is immediately written at the end of a journal file, whose name is the
1176 message id followed by &`-J`&. At the end of a delivery run, if there are some
1177 addresses left to be tried again later, the first spool file (the &`-H`& file)
1178 is updated to indicate which these are, and the journal file is then deleted.
1179 Updating the spool file is done by writing a new file and renaming it, to
1180 minimize the possibility of data loss.
1182 Should the system or Exim crash after a successful delivery but before
1183 the spool file has been updated, the journal is left lying around. The next
1184 time Exim attempts to deliver the message, it reads the journal file and
1185 updates the spool file before proceeding. This minimizes the chances of double
1186 deliveries caused by crashes.
1190 .section "Processing an address for delivery" "SECTprocaddress"
1191 .cindex "drivers" "definition of"
1192 .cindex "router" "definition of"
1193 .cindex "transport" "definition of"
1194 The main delivery processing elements of Exim are called &'routers'& and
1195 &'transports'&, and collectively these are known as &'drivers'&. Code for a
1196 number of them is provided in the source distribution, and compile-time options
1197 specify which ones are included in the binary. Runtime options specify which
1198 ones are actually used for delivering messages.
1200 .cindex "drivers" "instance definition"
1201 Each driver that is specified in the runtime configuration is an &'instance'&
1202 of that particular driver type. Multiple instances are allowed; for example,
1203 you can set up several different &(smtp)& transports, each with different
1204 option values that might specify different ports or different timeouts. Each
1205 instance has its own identifying name. In what follows we will normally use the
1206 instance name when discussing one particular instance (that is, one specific
1207 configuration of the driver), and the generic driver name when discussing
1208 the driver's features in general.
1210 A &'router'& is a driver that operates on an address, either determining how
1211 its delivery should happen, by assigning it to a specific transport, or
1212 converting the address into one or more new addresses (for example, via an
1213 alias file). A router may also explicitly choose to fail an address, causing it
1214 to be bounced.
1216 A &'transport'& is a driver that transmits a copy of the message from Exim's
1217 spool to some destination. There are two kinds of transport: for a &'local'&
1218 transport, the destination is a file or a pipe on the local host, whereas for a
1219 &'remote'& transport the destination is some other host. A message is passed
1220 to a specific transport as a result of successful routing. If a message has
1221 several recipients, it may be passed to a number of different transports.
1223 .cindex "preconditions" "definition of"
1224 An address is processed by passing it to each configured router instance in
1225 turn, subject to certain preconditions, until a router accepts the address or
1226 specifies that it should be bounced. We will describe this process in more
1227 detail shortly. First, as a simple example, we consider how each recipient
1228 address in a message is processed in a small configuration of three routers.
1230 To make this a more concrete example, it is described in terms of some actual
1231 routers, but remember, this is only an example. You can configure Exim's
1232 routers in many different ways, and there may be any number of routers in a
1233 configuration.
1235 The first router that is specified in a configuration is often one that handles
1236 addresses in domains that are not recognized specifically by the local host.
1237 Typically these are addresses for arbitrary domains on the Internet. A precondition
1238 is set up which looks for the special domains known to the host (for example,
1239 its own domain name), and the router is run for addresses that do &'not'&
1240 match. Typically, this is a router that looks up domains in the DNS in order to
1241 find the hosts to which this address routes. If it succeeds, the address is
1242 assigned to a suitable SMTP transport; if it does not succeed, the router is
1243 configured to fail the address.
1245 The second router is reached only when the domain is recognized as one that
1246 &"belongs"& to the local host. This router does redirection &-- also known as
1247 aliasing and forwarding. When it generates one or more new addresses from the
1248 original, each of them is routed independently from the start. Otherwise, the
1249 router may cause an address to fail, or it may simply decline to handle the
1250 address, in which case the address is passed to the next router.
1252 The final router in many configurations is one that checks to see if the
1253 address belongs to a local mailbox. The precondition may involve a check to
1254 see if the local part is the name of a login account, or it may look up the
1255 local part in a file or a database. If its preconditions are not met, or if
1256 the router declines, we have reached the end of the routers. When this happens,
1257 the address is bounced.
1261 .section "Processing an address for verification" "SECID16"
1262 .cindex "router" "for verification"
1263 .cindex "verifying address" "overview"
1264 As well as being used to decide how to deliver to an address, Exim's routers
1265 are also used for &'address verification'&. Verification can be requested as
1266 one of the checks to be performed in an ACL for incoming messages, on both
1267 sender and recipient addresses, and it can be tested using the &%-bv%& and
1268 &%-bvs%& command line options.
1270 When an address is being verified, the routers are run in &"verify mode"&. This
1271 does not affect the way the routers work, but it is a state that can be
1272 detected. By this means, a router can be skipped or made to behave differently
1273 when verifying. A common example is a configuration in which the first router
1274 sends all messages to a message-scanning program unless they have been
1275 previously scanned. Thus, the first router accepts all addresses without any
1276 checking, making it useless for verifying. Normally, the &%no_verify%& option
1277 would be set for such a router, causing it to be skipped in verify mode.
1282 .section "Running an individual router" "SECTrunindrou"
1283 .cindex "router" "running details"
1284 .cindex "preconditions" "checking"
1285 .cindex "router" "result of running"
1286 As explained in the example above, a number of preconditions are checked before
1287 running a router. If any are not met, the router is skipped, and the address is
1288 passed to the next router. When all the preconditions on a router &'are'& met,
1289 the router is run. What happens next depends on the outcome, which is one of
1290 the following:
1292 .ilist
1293 &'accept'&: The router accepts the address, and either assigns it to a
1294 transport or generates one or more &"child"& addresses. Processing the
1295 original address ceases
1296 .oindex "&%unseen%&"
1297 unless the &%unseen%& option is set on the router. This option
1298 can be used to set up multiple deliveries with different routing (for example,
1299 for keeping archive copies of messages). When &%unseen%& is set, the address is
1300 passed to the next router. Normally, however, an &'accept'& return marks the
1301 end of routing.
1303 Any child addresses generated by the router are processed independently,
1304 starting with the first router by default. It is possible to change this by
1305 setting the &%redirect_router%& option to specify which router to start at for
1306 child 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
1310 requests that the address be passed to another router. By default, the address
1311 is passed to the next router, but this can be changed by setting the
1312 &%pass_router%& option. However, (unlike &%redirect_router%&) the named router
1313 must be below the current router (to avoid loops).
1314 .next
1315 &'decline'&: The router declines to accept the address because it does not
1316 recognize it at all. By default, the address is passed to the next router, but
1317 this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1318 set, 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
1322 the generation of a bounce message. There is no further processing of the
1323 original address unless &%unseen%& is set on the router.
1324 .next
1325 &'defer'&: The router cannot handle the address at the present time. (A
1326 database may be offline, or a DNS lookup may have timed out.) No further
1327 processing of the address happens in this delivery attempt. It is tried again
1328 next time the message is considered for delivery.
1329 .next
1330 &'error'&: There is some error in the router (for example, a syntax error in
1331 its configuration). The action is as for defer.
1332 .endlist
1334 If an address reaches the end of the routers without having been accepted by
1335 any of them, it is bounced as unrouteable. The default error message in this
1336 situation is &"unrouteable address"&, but you can set your own message by
1337 making use of the &%cannot_route_message%& option. This can be set for any
1338 router; the value from the last router that &"saw"& the address is used.
1340 Sometimes while routing you want to fail a delivery when some conditions are
1341 met but others are not, instead of passing the address on for further routing.
1342 You can do this by having a second router that explicitly fails the delivery
1343 when the relevant conditions are met. The &(redirect)& router has a &"fail"&
1344 facility for this purpose.
1347 .section "Duplicate addresses" "SECID17"
1348 .cindex "case of local parts"
1349 .cindex "address duplicate, discarding"
1350 .cindex "duplicate addresses"
1351 Once routing is complete, Exim scans the addresses that are assigned to local
1352 and remote transports and discards any duplicates that it finds. During this
1353 check, local parts are treated case-sensitively. This happens only when
1354 actually delivering a message; when testing routers with &%-bt%&, all the
1355 routed addresses are shown.
1359 .section "Router preconditions" "SECTrouprecon"
1360 .cindex "router" "preconditions, order of processing"
1361 .cindex "preconditions" "order of processing"
1362 The preconditions that are tested for each router are listed below, in the
1363 order in which they are tested. The individual configuration options are
1364 described in more detail in chapter &<<CHAProutergeneric>>&.
1366 .ilist
1367 .cindex affix "router precondition"
1368 The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
1369 the local parts handled by the router may or must have certain prefixes and/or
1370 suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1371 skipped. These conditions are tested first. When an affix is present, it is
1372 removed from the local part before further processing, including the evaluation
1373 of any other conditions.
1374 .next
1375 Routers can be designated for use only when not verifying an address, that is,
1376 only when routing it for delivery (or testing its delivery routing). If the
1377 &%verify%& option is set false, the router is skipped when Exim is verifying an
1378 address.
1379 Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1380 &%verify_recipient%&, which independently control the use of the router for
1381 sender and recipient verification. You can set these options directly if
1382 you want a router to be used for only one type of verification.
1383 Note that cutthrough delivery is classed as a recipient verification for this purpose.
1384 .next
1385 If the &%address_test%& option is set false, the router is skipped when Exim is
1386 run with the &%-bt%& option to test an address routing. This can be helpful
1387 when the first router sends all new messages to a scanner of some sort; it
1388 makes it possible to use &%-bt%& to test subsequent delivery routing without
1389 having to simulate the effect of the scanner.
1390 .next
1391 Routers can be designated for use only when verifying an address, as
1392 opposed to routing it for delivery. The &%verify_only%& option controls this.
1393 Again, cutthrough delivery counts as a verification.
1394 .next
1395 Individual routers can be explicitly skipped when running the routers to
1396 check an address given in the SMTP EXPN command (see the &%expn%& option).
1397 .next
1398 If the &%domains%& option is set, the domain of the address must be in the set
1399 of domains that it defines.
1400 .next
1401 .vindex "&$local_part_prefix$&"
1402 .vindex "&$local_part$&"
1403 .vindex "&$local_part_suffix$&"
1404 .cindex affix "router precondition"
1405 If the &%local_parts%& option is set, the local part of the address must be in
1406 the set of local parts that it defines. If &%local_part_prefix%& or
1407 &%local_part_suffix%& is in use, the prefix or suffix is removed from the local
1408 part before this check. If you want to do precondition tests on local parts
1409 that include affixes, you can do so by using a &%condition%& option (see below)
1410 that uses the variables &$local_part$&, &$local_part_prefix$&, and
1411 &$local_part_suffix$& as necessary.
1412 .next
1413 .vindex "&$local_user_uid$&"
1414 .vindex "&$local_user_gid$&"
1415 .vindex "&$home$&"
1416 If the &%check_local_user%& option is set, the local part must be the name of
1417 an account on the local host. If this check succeeds, the uid and gid of the
1418 local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1419 user's home directory is placed in &$home$&; these values can be used in the
1420 remaining preconditions.
1421 .next
1422 If the &%router_home_directory%& option is set, it is expanded at this point,
1423 because it overrides the value of &$home$&. If this expansion were left till
1424 later, the value of &$home$& as set by &%check_local_user%& would be used in
1425 subsequent tests. Having two different values of &$home$& in the same router
1426 could lead to confusion.
1427 .next
1428 If the &%senders%& option is set, the envelope sender address must be in the
1429 set of addresses that it defines.
1430 .next
1431 If the &%require_files%& option is set, the existence or non-existence of
1432 specified files is tested.
1433 .next
1434 .cindex "customizing" "precondition"
1435 If the &%condition%& option is set, it is evaluated and tested. This option
1436 uses an expanded string to allow you to set up your own custom preconditions.
1437 Expanded strings are described in chapter &<<CHAPexpand>>&.
1438 .endlist
1441 Note that &%require_files%& comes near the end of the list, so you cannot use
1442 it to check for the existence of a file in which to lookup up a domain, local
1443 part, or sender. However, as these options are all expanded, you can use the
1444 &%exists%& expansion condition to make such tests within each condition. The
1445 &%require_files%& option is intended for checking files that the router may be
1446 going to use internally, or which are needed by a specific transport (for
1447 example, &_.procmailrc_&).
1451 .section "Delivery in detail" "SECID18"
1452 .cindex "delivery" "in detail"
1453 When a message is to be delivered, the sequence of events is as follows:
1455 .ilist
1456 If a system-wide filter file is specified, the message is passed to it. The
1457 filter may add recipients to the message, replace the recipients, discard the
1458 message, cause a new message to be generated, or cause the message delivery to
1459 fail. The format of the system filter file is the same as for Exim user filter
1460 files, described in the separate document entitled &'Exim's interfaces to mail
1461 filtering'&.
1462 .cindex "Sieve filter" "not available for system filter"
1463 (&*Note*&: Sieve cannot be used for system filter files.)
1465 Some additional features are available in system filters &-- see chapter
1466 &<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
1467 filter only once per delivery attempt, however many recipients it has. However,
1468 if there are several delivery attempts because one or more addresses could not
1469 be immediately delivered, the system filter is run each time. The filter
1470 condition &%first_delivery%& can be used to detect the first run of the system
1471 filter.
1472 .next
1473 Each recipient address is offered to each configured router, in turn, subject to
1474 its preconditions, until one is able to handle it. If no router can handle the
1475 address, that is, if they all decline, the address is failed. Because routers
1476 can be targeted at particular domains, several locally handled domains can be
1477 processed entirely independently of each other.
1478 .next
1479 .cindex "routing" "loops in"
1480 .cindex "loop" "while routing"
1481 A router that accepts an address may assign it to a local or a remote
1482 transport. However, the transport is not run at this time. Instead, the address
1483 is placed on a list for the particular transport, which will be run later.
1484 Alternatively, the router may generate one or more new addresses (typically
1485 from alias, forward, or filter files). New addresses are fed back into this
1486 process from the top, but in order to avoid loops, a router ignores any address
1487 which has an identically-named ancestor that was processed by itself.
1488 .next
1489 When all the routing has been done, addresses that have been successfully
1490 handled are passed to their assigned transports. When local transports are
1491 doing real local deliveries, they handle only one address at a time, but if a
1492 local transport is being used as a pseudo-remote transport (for example, to
1493 collect batched SMTP messages for transmission by some other means) multiple
1494 addresses can be handled. Remote transports can always handle more than one
1495 address at a time, but can be configured not to do so, or to restrict multiple
1496 addresses to the same domain.
1497 .next
1498 Each local delivery to a file or a pipe runs in a separate process under a
1499 non-privileged uid, and these deliveries are run one at a time. Remote
1500 deliveries also run in separate processes, normally under a uid that is private
1501 to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
1502 run in parallel. The maximum number of simultaneous remote deliveries for any
1503 one message is set by the &%remote_max_parallel%& option.
1504 The order in which deliveries are done is not defined, except that all local
1505 deliveries happen before any remote deliveries.
1506 .next
1507 .cindex "queue runner"
1508 When it encounters a local delivery during a queue run, Exim checks its retry
1509 database to see if there has been a previous temporary delivery failure for the
1510 address before running the local transport. If there was a previous failure,
1511 Exim does not attempt a new delivery until the retry time for the address is
1512 reached. However, this happens only for delivery attempts that are part of a
1513 queue run. Local deliveries are always attempted when delivery immediately
1514 follows message reception, even if retry times are set for them. This makes for
1515 better behaviour if one particular message is causing problems (for example,
1516 causing quota overflow, or provoking an error in a filter file).
1517 .next
1518 .cindex "delivery" "retry in remote transports"
1519 Remote transports do their own retry handling, since an address may be
1520 deliverable to one of a number of hosts, each of which may have a different
1521 retry time. If there have been previous temporary failures and no host has
1522 reached its retry time, no delivery is attempted, whether in a queue run or
1523 not. See chapter &<<CHAPretry>>& for details of retry strategies.
1524 .next
1525 If there were any permanent errors, a bounce message is returned to an
1526 appropriate address (the sender in the common case), with details of the error
1527 for each failing address. Exim can be configured to send copies of bounce
1528 messages to other addresses.
1529 .next
1530 .cindex "delivery" "deferral"
1531 If one or more addresses suffered a temporary failure, the message is left on
1532 the queue, to be tried again later. Delivery of these addresses is said to be
1533 &'deferred'&.
1534 .next
1535 When all the recipient addresses have either been delivered or bounced,
1536 handling of the message is complete. The spool files and message log are
1537 deleted, though the message log can optionally be preserved if required.
1538 .endlist
1543 .section "Retry mechanism" "SECID19"
1544 .cindex "delivery" "retry mechanism"
1545 .cindex "retry" "description of mechanism"
1546 .cindex "queue runner"
1547 Exim's mechanism for retrying messages that fail to get delivered at the first
1548 attempt is the queue runner process. You must either run an Exim daemon that
1549 uses the &%-q%& option with a time interval to start queue runners at regular
1550 intervals or use some other means (such as &'cron'&) to start them. If you do
1551 not arrange for queue runners to be run, messages that fail temporarily at the
1552 first attempt will remain in your queue forever. A queue runner process works
1553 its way through the queue, one message at a time, trying each delivery that has
1554 passed its retry time.
1555 You can run several queue runners at once.
1557 Exim uses a set of configured rules to determine when next to retry the failing
1558 address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1559 should give up trying to deliver to the address, at which point it generates a
1560 bounce message. If no retry rules are set for a particular host, address, and
1561 error combination, no retries are attempted, and temporary errors are treated
1562 as permanent.
1566 .section "Temporary delivery failure" "SECID20"
1567 .cindex "delivery" "temporary failure"
1568 There are many reasons why a message may not be immediately deliverable to a
1569 particular address. Failure to connect to a remote machine (because it, or the
1570 connection to it, is down) is one of the most common. Temporary failures may be
1571 detected during routing as well as during the transport stage of delivery.
1572 Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1573 is on a file system where the user is over quota. Exim can be configured to
1574 impose its own quotas on local mailboxes; where system quotas are set they will
1575 also apply.
1577 If a host is unreachable for a period of time, a number of messages may be
1578 waiting for it by the time it recovers, and sending them in a single SMTP
1579 connection is clearly beneficial. Whenever a delivery to a remote host is
1580 deferred,
1581 .cindex "hints database" "deferred deliveries"
1582 Exim makes a note in its hints database, and whenever a successful
1583 SMTP delivery has happened, it looks to see if any other messages are waiting
1584 for the same host. If any are found, they are sent over the same SMTP
1585 connection, subject to a configuration limit as to the maximum number in any
1586 one connection.
1590 .section "Permanent delivery failure" "SECID21"
1591 .cindex "delivery" "permanent failure"
1592 .cindex "bounce message" "when generated"
1593 When a message cannot be delivered to some or all of its intended recipients, a
1594 bounce message is generated. Temporary delivery failures turn into permanent
1595 errors when their timeout expires. All the addresses that fail in a given
1596 delivery attempt are listed in a single message. If the original message has
1597 many recipients, it is possible for some addresses to fail in one delivery
1598 attempt and others to fail subsequently, giving rise to more than one bounce
1599 message. The wording of bounce messages can be customized by the administrator.
1600 See chapter &<<CHAPemsgcust>>& for details.
1602 .cindex "&'X-Failed-Recipients:'& header line"
1603 Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
1604 failed addresses, for the benefit of programs that try to analyse such messages
1605 automatically.
1607 .cindex "bounce message" "recipient of"
1608 A bounce message is normally sent to the sender of the original message, as
1609 obtained from the message's envelope. For incoming SMTP messages, this is the
1610 address given in the MAIL command. However, when an address is expanded via a
1611 forward or alias file, an alternative address can be specified for delivery
1612 failures of the generated addresses. For a mailing list expansion (see section
1613 &<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1614 of the list.
1618 .section "Failures to deliver bounce messages" "SECID22"
1619 .cindex "bounce message" "failure to deliver"
1620 If a bounce message (either locally generated or received from a remote host)
1621 itself suffers a permanent delivery failure, the message is left in the queue,
1622 but it is frozen, awaiting the attention of an administrator. There are options
1623 that can be used to make Exim discard such failed messages, or to keep them
1624 for only a short time (see &%timeout_frozen_after%& and
1625 &%ignore_bounce_errors_after%&).
1631 . ////////////////////////////////////////////////////////////////////////////
1632 . ////////////////////////////////////////////////////////////////////////////
1634 .chapter "Building and installing Exim" "CHID3"
1635 .scindex IIDbuex "building Exim"
1637 .section "Unpacking" "SECID23"
1638 Exim is distributed as a gzipped or bzipped tar file which, when unpacked,
1639 creates a directory with the name of the current release (for example,
1640 &_exim-&version()_&) into which the following files are placed:
1642 .table2 140pt
1643 .irow &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1644 .irow &_CHANGES_& "contains a reference to where changes are &&&
1645 documented"
1646 .irow &_LICENCE_& "the GNU General Public Licence"
1647 .irow &_Makefile_& "top-level make file"
1648 .irow &_NOTICE_& "conditions for the use of Exim"
1649 .irow &_README_& "list of files, directories and simple build &&&
1650 instructions"
1651 .endtable
1653 Other files whose names begin with &_README_& may also be present. The
1654 following subdirectories are created:
1656 .table2 140pt
1657 .irow &_Local_& "an empty directory for local configuration files"
1658 .irow &_OS_& "OS-specific files"
1659 .irow &_doc_& "documentation files"
1660 .irow &_exim_monitor_& "source files for the Exim monitor"
1661 .irow &_scripts_& "scripts used in the build process"
1662 .irow &_src_& "remaining source files"
1663 .irow &_util_& "independent utilities"
1664 .endtable
1666 The main utility programs are contained in the &_src_& directory and are built
1667 with the Exim binary. The &_util_& directory contains a few optional scripts
1668 that may be useful to some sites.
1671 .section "Multiple machine architectures and operating systems" "SECID24"
1672 .cindex "building Exim" "multiple OS/architectures"
1673 The building process for Exim is arranged to make it easy to build binaries for
1674 a number of different architectures and operating systems from the same set of
1675 source files. Compilation does not take place in the &_src_& directory.
1676 Instead, a &'build directory'& is created for each architecture and operating
1677 system.
1678 .cindex "symbolic link" "to build directory"
1679 Symbolic links to the sources are installed in this directory, which is where
1680 the actual building takes place. In most cases, Exim can discover the machine
1681 architecture and operating system for itself, but the defaults can be
1682 overridden if necessary.
1683 .cindex compiler requirements
1684 .cindex compiler version
1685 A C99-capable compiler will be required for the build.
1688 .section "PCRE library" "SECTpcre"
1689 .cindex "PCRE library"
1690 Exim no longer has an embedded PCRE library as the vast majority of
1691 modern systems include PCRE as a system library, although you may need to
1692 install the PCRE package or the PCRE development package for your operating
1693 system. If your system has a normal PCRE installation the Exim build
1694 process will need no further configuration. If the library or the
1695 headers are in an unusual location you will need to either set the PCRE_LIBS
1696 and INCLUDE directives appropriately,
1697 or set PCRE_CONFIG=yes to use the installed &(pcre-config)& command.
1698 If your operating system has no
1699 PCRE support then you will need to obtain and build the current PCRE
1700 from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/).
1701 More information on PCRE is available at &url(https://www.pcre.org/).
1703 .section "DBM libraries" "SECTdb"
1704 .cindex "DBM libraries" "discussion of"
1705 .cindex "hints database" "DBM files used for"
1706 Even if you do not use any DBM files in your configuration, Exim still needs a
1707 DBM library in order to operate, because it uses indexed files for its hints
1708 databases. Unfortunately, there are a number of DBM libraries in existence, and
1709 different operating systems often have different ones installed.
1711 .cindex "Solaris" "DBM library for"
1712 .cindex "IRIX, DBM library for"
1713 .cindex "BSD, DBM library for"
1714 .cindex "Linux, DBM library for"
1715 If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1716 Linux distribution, the DBM configuration should happen automatically, and you
1717 may be able to ignore this section. Otherwise, you may have to learn more than
1718 you would like about DBM libraries from what follows.
1720 .cindex "&'ndbm'& DBM library"
1721 Licensed versions of Unix normally contain a library of DBM functions operating
1722 via the &'ndbm'& interface, and this is what Exim expects by default. Free
1723 versions of Unix seem to vary in what they contain as standard. In particular,
1724 some early versions of Linux have no default DBM library, and different
1725 distributors have chosen to bundle different libraries with their packaged
1726 versions. However, the more recent releases seem to have standardized on the
1727 Berkeley DB library.
1729 Different DBM libraries have different conventions for naming the files they
1730 use. When a program opens a file called &_dbmfile_&, there are several
1731 possibilities:
1733 .olist
1734 A traditional &'ndbm'& implementation, such as that supplied as part of
1735 Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1736 .next
1737 .cindex "&'gdbm'& DBM library"
1738 The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
1739 compatibility interface it makes two different hard links to it with names
1740 &_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
1741 filename is used unmodified.
1742 .next
1743 .cindex "Berkeley DB library"
1744 The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1745 operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1746 programmer exactly the same as the traditional &'ndbm'& implementation.
1747 .next
1748 If the Berkeley package is used in its native mode, it operates on a single
1749 file called &_dbmfile_&; the programmer's interface is somewhat different to
1750 the traditional &'ndbm'& interface.
1751 .next
1752 To complicate things further, there are several very different versions of the
1753 Berkeley DB package. Version 1.85 was stable for a very long time, releases
1754 2.&'x'& and 3.&'x'& were current for a while, but the latest versions when Exim last revamped support were numbered 4.&'x'&.
1755 Maintenance of some of the earlier releases has ceased. All versions of
1756 Berkeley DB could be obtained from
1757 &url(http://www.sleepycat.com/), which is now a redirect to their new owner's
1758 page with far newer versions listed.
1759 It is probably wise to plan to move your storage configurations away from
1760 Berkeley DB format, as today there are smaller and simpler alternatives more
1761 suited to Exim's usage model.
1762 .next
1763 .cindex "&'tdb'& DBM library"
1764 Yet another DBM library, called &'tdb'&, is available from
1765 &url(https://sourceforge.net/projects/tdb/files/). It has its own interface, and also
1766 operates on a single file.
1767 .endlist
1769 .cindex "USE_DB"
1770 .cindex "DBM libraries" "configuration for building"
1771 Exim and its utilities can be compiled to use any of these interfaces. In order
1772 to use any version of the Berkeley DB package in native mode, you must set
1773 USE_DB in an appropriate configuration file (typically
1774 &_Local/Makefile_&). For example:
1775 .code
1776 USE_DB=yes
1777 .endd
1778 Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1779 error is diagnosed if you set more than one of these.
1781 At the lowest level, the build-time configuration sets none of these options,
1782 thereby assuming an interface of type (1). However, some operating system
1783 configuration files (for example, those for the BSD operating systems and
1784 Linux) assume type (4) by setting USE_DB as their default, and the
1785 configuration files for Cygwin set USE_GDBM. Anything you set in
1786 &_Local/Makefile_&, however, overrides these system defaults.
1788 As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1789 necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1790 in one of these lines:
1791 .code
1792 DBMLIB = -ldb
1793 DBMLIB = -ltdb
1794 .endd
1795 Settings like that will work if the DBM library is installed in the standard
1796 place. Sometimes it is not, and the library's header file may also not be in
1797 the default path. You may need to set INCLUDE to specify where the header
1798 file is, and to specify the path to the library more fully in DBMLIB, as in
1799 this example:
1800 .code
1801 INCLUDE=-I/usr/local/include/db-4.1
1802 DBMLIB=/usr/local/lib/db-4.1/libdb.a
1803 .endd
1804 There is further detailed discussion about the various DBM libraries in the
1805 file &_doc/dbm.discuss.txt_& in the Exim distribution.
1809 .section "Pre-building configuration" "SECID25"
1810 .cindex "building Exim" "pre-building configuration"
1811 .cindex "configuration for building Exim"
1812 .cindex "&_Local/Makefile_&"
1813 .cindex "&_src/EDITME_&"
1814 Before building Exim, a local configuration file that specifies options
1815 independent of any operating system has to be created with the name
1816 &_Local/Makefile_&. A template for this file is supplied as the file
1817 &_src/EDITME_&, and it contains full descriptions of all the option settings
1818 therein. These descriptions are therefore not repeated here. If you are
1819 building Exim for the first time, the simplest thing to do is to copy
1820 &_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
1822 There are three settings that you must supply, because Exim will not build
1823 without them. They are the location of the runtime configuration file
1824 (CONFIGURE_FILE), the directory in which Exim binaries will be installed
1825 (BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1826 maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1827 a colon-separated list of filenames; Exim uses the first of them that exists.
1829 There are a few other parameters that can be specified either at build time or
1830 at runtime, to enable the same binary to be used on a number of different
1831 machines. However, if the locations of Exim's spool directory and log file
1832 directory (if not within the spool directory) are fixed, it is recommended that
1833 you specify them in &_Local/Makefile_& instead of at runtime, so that errors
1834 detected early in Exim's execution (such as a malformed configuration file) can
1835 be logged.
1837 .cindex "content scanning" "specifying at build time"
1838 Exim's interfaces for calling virus and spam scanning software directly from
1839 access control lists are not compiled by default. If you want to include these
1840 facilities, you need to set
1841 .code
1843 .endd
1844 in your &_Local/Makefile_&. For details of the facilities themselves, see
1845 chapter &<<CHAPexiscan>>&.
1848 .cindex "&_Local/eximon.conf_&"
1849 .cindex "&_exim_monitor/EDITME_&"
1850 If you are going to build the Exim monitor, a similar configuration process is
1851 required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1852 your installation and saved under the name &_Local/eximon.conf_&. If you are
1853 happy with the default settings described in &_exim_monitor/EDITME_&,
1854 &_Local/eximon.conf_& can be empty, but it must exist.
1856 This is all the configuration that is needed in straightforward cases for known
1857 operating systems. However, the building process is set up so that it is easy
1858 to override options that are set by default or by operating-system-specific
1859 configuration files, for example, to change the C compiler, which
1860 defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1861 do this.
1865 .section "Support for iconv()" "SECID26"
1866 .cindex "&[iconv()]& support"
1867 .cindex "RFC 2047"
1868 The contents of header lines in messages may be encoded according to the rules
1869 described RFC 2047. This makes it possible to transmit characters that are not
1870 in the ASCII character set, and to label them as being in a particular
1871 character set. When Exim is inspecting header lines by means of the &%$h_%&
1872 mechanism, it decodes them, and translates them into a specified character set
1873 (default is set at build time). The translation is possible only if the operating system
1874 supports the &[iconv()]& function.
1876 However, some of the operating systems that supply &[iconv()]& do not support
1877 very many conversions. The GNU &%libiconv%& library (available from
1878 &url(https://www.gnu.org/software/libiconv/)) can be installed on such
1879 systems to remedy this deficiency, as well as on systems that do not supply
1880 &[iconv()]& at all. After installing &%libiconv%&, you should add
1881 .code
1882 HAVE_ICONV=yes
1883 .endd
1884 to your &_Local/Makefile_& and rebuild Exim.
1888 .section "Including TLS/SSL encryption support" "SECTinctlsssl"
1889 .cindex "TLS" "including support for TLS"
1890 .cindex "encryption" "including support for"
1891 .cindex "SUPPORT_TLS"
1892 .cindex "OpenSSL" "building Exim with"
1893 .cindex "GnuTLS" "building Exim with"
1894 Exim can be built to support encrypted SMTP connections, using the STARTTLS
1895 command as per RFC 2487. It can also support legacy clients that expect to
1896 start a TLS session immediately on connection to a non-standard port (see the
1897 &%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
1898 line option).
1900 If you want to build Exim with TLS support, you must first install either the
1901 OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1902 implementing SSL.
1904 If OpenSSL is installed, you should set
1905 .code
1906 SUPPORT_TLS=yes
1907 TLS_LIBS=-lssl -lcrypto
1908 .endd
1909 in &_Local/Makefile_&. You may also need to specify the locations of the
1910 OpenSSL library and include files. For example:
1911 .code
1912 SUPPORT_TLS=yes
1913 TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1914 TLS_INCLUDE=-I/usr/local/openssl/include/
1915 .endd
1916 .cindex "pkg-config" "OpenSSL"
1917 If you have &'pkg-config'& available, then instead you can just use:
1918 .code
1919 SUPPORT_TLS=yes
1920 USE_OPENSSL_PC=openssl
1921 .endd
1922 .cindex "USE_GNUTLS"
1923 If GnuTLS is installed, you should set
1924 .code
1925 SUPPORT_TLS=yes
1926 USE_GNUTLS=yes
1927 TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1928 .endd
1929 in &_Local/Makefile_&, and again you may need to specify the locations of the
1930 library and include files. For example:
1931 .code
1932 SUPPORT_TLS=yes
1933 USE_GNUTLS=yes
1934 TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1935 TLS_INCLUDE=-I/usr/gnu/include
1936 .endd
1937 .cindex "pkg-config" "GnuTLS"
1938 If you have &'pkg-config'& available, then instead you can just use:
1939 .code
1940 SUPPORT_TLS=yes
1941 USE_GNUTLS=yes
1942 USE_GNUTLS_PC=gnutls
1943 .endd
1945 You do not need to set TLS_INCLUDE if the relevant directory is already
1946 specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1947 given in chapter &<<CHAPTLS>>&.
1952 .section "Use of tcpwrappers" "SECID27"
1954 .cindex "tcpwrappers, building Exim to support"
1955 .cindex "USE_TCP_WRAPPERS"
1957 .cindex "tcp_wrappers_daemon_name"
1958 Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1959 SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
1960 alternative to Exim's own checking facilities for installations that are
1961 already making use of &'tcpwrappers'& for other purposes. To do this, you
1962 should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1963 &_tcpd.h_& to be available at compile time, and also ensure that the library
1964 &_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1965 EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1966 you might have
1967 .code
1969 CFLAGS=-O -I/usr/local/include
1970 EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1971 .endd
1972 in &_Local/Makefile_&. The daemon name to use in the &'tcpwrappers'& control
1973 files is &"exim"&. For example, the line
1974 .code
1975 exim : LOCAL 192.168.1. .friendly.domain.example
1976 .endd
1977 in your &_/etc/hosts.allow_& file allows connections from the local host, from
1978 the subnet, and from all hosts in &'friendly.domain.example'&.
1979 All other connections are denied. The daemon name used by &'tcpwrappers'&
1980 can be changed at build time by setting TCP_WRAPPERS_DAEMON_NAME in
1981 &_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the
1982 configure file. Consult the &'tcpwrappers'& documentation for
1983 further details.
1986 .section "Including support for IPv6" "SECID28"
1987 .cindex "IPv6" "including support for"
1988 Exim contains code for use on systems that have IPv6 support. Setting
1989 &`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
1990 it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1991 where the IPv6 support is not fully integrated into the normal include and
1992 library files.
1994 Two different types of DNS record for handling IPv6 addresses have been
1995 defined. AAAA records (analogous to A records for IPv4) are in use, and are
1996 currently seen as the mainstream. Another record type called A6 was proposed
1997 as better than AAAA because it had more flexibility. However, it was felt to be
1998 over-complex, and its status was reduced to &"experimental"&.
1999 Exim used to
2000 have a compile option for including A6 record support but this has now been
2001 withdrawn.
2005 .section "Dynamically loaded lookup module support" "SECTdynamicmodules"
2006 .cindex "lookup modules"
2007 .cindex "dynamic modules"
2008 .cindex ".so building"
2009 On some platforms, Exim supports not compiling all lookup types directly into
2010 the main binary, instead putting some into external modules which can be loaded
2011 on demand.
2012 This permits packagers to build Exim with support for lookups with extensive
2013 library dependencies without requiring all users to install all of those
2014 dependencies.
2015 Most, but not all, lookup types can be built this way.
2017 Set &`LOOKUP_MODULE_DIR`& to the directory into which the modules will be
2018 installed; Exim will only load modules from that directory, as a security
2019 measure. You will need to set &`CFLAGS_DYNAMIC`& if not already defined
2020 for your OS; see &_OS/Makefile-Linux_& for an example.
2021 Some other requirements for adjusting &`EXTRALIBS`& may also be necessary,
2022 see &_src/EDITME_& for details.
2024 Then, for each module to be loaded dynamically, define the relevant
2025 &`LOOKUP_`&<&'lookup_type'&> flags to have the value "2" instead of "yes".
2026 For example, this will build in lsearch but load sqlite and mysql support
2027 on demand:
2028 .code
2032 .endd
2035 .section "The building process" "SECID29"
2036 .cindex "build directory"
2037 Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
2038 created, run &'make'& at the top level. It determines the architecture and
2039 operating system types, and creates a build directory if one does not exist.
2040 For example, on a Sun system running Solaris 8, the directory
2041 &_build-SunOS5-5.8-sparc_& is created.
2042 .cindex "symbolic link" "to source files"
2043 Symbolic links to relevant source files are installed in the build directory.
2045 If this is the first time &'make'& has been run, it calls a script that builds
2046 a make file inside the build directory, using the configuration files from the
2047 &_Local_& directory. The new make file is then passed to another instance of
2048 &'make'&. This does the real work, building a number of utility scripts, and
2049 then compiling and linking the binaries for the Exim monitor (if configured), a
2050 number of utility programs, and finally Exim itself. The command &`make
2051 makefile`& can be used to force a rebuild of the make file in the build
2052 directory, should this ever be necessary.
2054 If you have problems building Exim, check for any comments there may be in the
2055 &_README_& file concerning your operating system, and also take a look at the
2056 FAQ, where some common problems are covered.
2060 .section 'Output from &"make"&' "SECID283"
2061 The output produced by the &'make'& process for compile lines is often very
2062 unreadable, because these lines can be very long. For this reason, the normal
2063 output is suppressed by default, and instead output similar to that which
2064 appears when compiling the 2.6 Linux kernel is generated: just a short line for
2065 each module that is being compiled or linked. However, it is still possible to
2066 get the full output, by calling &'make'& like this:
2067 .code
2068 FULLECHO='' make -e
2069 .endd
2070 The value of FULLECHO defaults to &"@"&, the flag character that suppresses
2071 command reflection in &'make'&. When you ask for the full output, it is
2072 given in addition to the short output.
2076 .section "Overriding build-time options for Exim" "SECToverride"
2077 .cindex "build-time options, overriding"
2078 The main make file that is created at the beginning of the building process
2079 consists of the concatenation of a number of files which set configuration
2080 values, followed by a fixed set of &'make'& instructions. If a value is set
2081 more than once, the last setting overrides any previous ones. This provides a
2082 convenient way of overriding defaults. The files that are concatenated are, in
2083 order:
2084 .display
2085 &_OS/Makefile-Default_&
2086 &_OS/Makefile-_&<&'ostype'&>
2087 &_Local/Makefile_&
2088 &_Local/Makefile-_&<&'ostype'&>
2089 &_Local/Makefile-_&<&'archtype'&>
2090 &_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
2091 &_OS/Makefile-Base_&
2092 .endd
2093 .cindex "&_Local/Makefile_&"
2094 .cindex "building Exim" "operating system type"
2095 .cindex "building Exim" "architecture type"
2096 where <&'ostype'&> is the operating system type and <&'archtype'&> is the
2097 architecture type. &_Local/Makefile_& is required to exist, and the building
2098 process fails if it is absent. The other three &_Local_& files are optional,
2099 and are often not needed.
2101 The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
2102 called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
2103 the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
2104 values are used, thereby providing a means of forcing particular settings.
2105 Otherwise, the scripts try to get values from the &%uname%& command. If this
2106 fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
2107 of &'ad hoc'& transformations are then applied, to produce the standard names
2108 that Exim expects. You can run these scripts directly from the shell in order
2109 to find out what values are being used on your system.
2112 &_OS/Makefile-Default_& contains comments about the variables that are set
2113 therein. Some (but not all) are mentioned below. If there is something that
2114 needs changing, review the contents of this file and the contents of the make
2115 file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
2116 default values are.
2119 .cindex "building Exim" "overriding default settings"
2120 If you need to change any of the values that are set in &_OS/Makefile-Default_&
2121 or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
2122 need to change the original files. Instead, you should make the changes by
2123 putting the new values in an appropriate &_Local_& file. For example,
2124 .cindex "Tru64-Unix build-time settings"
2125 when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2126 formerly DEC-OSF1) operating system, it is necessary to specify that the C
2127 compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2128 called with the option &%-std1%&, to make it recognize some of the features of
2129 Standard C that Exim uses. (Most other compilers recognize Standard C by
2130 default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
2131 containing the lines
2132 .code
2133 CC=cc
2134 CFLAGS=-std1
2135 .endd
2136 If you are compiling for just one operating system, it may be easier to put
2137 these lines directly into &_Local/Makefile_&.
2139 Keeping all your local configuration settings separate from the distributed
2140 files makes it easy to transfer them to new versions of Exim simply by copying
2141 the contents of the &_Local_& directory.
2144 .cindex "NIS lookup type" "including support for"
2145 .cindex "NIS+ lookup type" "including support for"
2146 .cindex "LDAP" "including support for"
2147 .cindex "lookup" "inclusion in binary"
2148 Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2149 lookup, but not all systems have these components installed, so the default is
2150 not to include the relevant code in the binary. All the different kinds of file
2151 and database lookup that Exim supports are implemented as separate code modules
2152 which are included only if the relevant compile-time options are set. In the
2153 case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2154 .code
2155 LOOKUP_LDAP=yes
2156 LOOKUP_NIS=yes
2158 .endd
2159 and similar settings apply to the other lookup types. They are all listed in
2160 &_src/EDITME_&. In many cases the relevant include files and interface
2161 libraries need to be installed before compiling Exim.
2162 .cindex "cdb" "including support for"
2163 However, there are some optional lookup types (such as cdb) for which
2164 the code is entirely contained within Exim, and no external include
2165 files or libraries are required. When a lookup type is not included in the
2166 binary, attempts to configure Exim to use it cause runtime configuration
2167 errors.
2169 .cindex "pkg-config" "lookups"
2170 .cindex "pkg-config" "authenticators"
2171 Many systems now use a tool called &'pkg-config'& to encapsulate information
2172 about how to compile against a library; Exim has some initial support for
2173 being able to use pkg-config for lookups and authenticators. For any given
2174 makefile variable which starts &`LOOKUP_`& or &`AUTH_`&, you can add a new
2175 variable with the &`_PC`& suffix in the name and assign as the value the
2176 name of the package to be queried. The results of querying via the
2177 &'pkg-config'& command will be added to the appropriate Makefile variables
2178 with &`+=`& directives, so your version of &'make'& will need to support that
2179 syntax. For instance:
2180 .code
2182 LOOKUP_SQLITE_PC=sqlite3
2183 AUTH_GSASL=yes
2184 AUTH_GSASL_PC=libgsasl
2186 AUTH_HEIMDAL_GSSAPI_PC=heimdal-gssapi
2187 .endd
2189 .cindex "Perl" "including support for"
2190 Exim can be linked with an embedded Perl interpreter, allowing Perl
2191 subroutines to be called during string expansion. To enable this facility,
2192 .code
2193 EXIM_PERL=perl.o
2194 .endd
2195 must be defined in &_Local/Makefile_&. Details of this facility are given in
2196 chapter &<<CHAPperl>>&.
2198 .cindex "X11 libraries, location of"
2199 The location of the X11 libraries is something that varies a lot between
2200 operating systems, and there may be different versions of X11 to cope
2201 with. Exim itself makes no use of X11, but if you are compiling the Exim
2202 monitor, the X11 libraries must be available.
2203 The following three variables are set in &_OS/Makefile-Default_&:
2204 .code
2205 X11=/usr/X11R6
2206 XINCLUDE=-I$(X11)/include
2207 XLFLAGS=-L$(X11)/lib
2208 .endd
2209 These are overridden in some of the operating-system configuration files. For
2210 example, in &_OS/Makefile-SunOS5_& there is
2211 .code
2212 X11=/usr/openwin
2213 XINCLUDE=-I$(X11)/include
2214 XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2215 .endd
2216 If you need to override the default setting for your operating system, place a
2217 definition of all three of these variables into your
2218 &_Local/Makefile-<ostype>_& file.
2220 .cindex "EXTRALIBS"
2221 If you need to add any extra libraries to the link steps, these can be put in a
2222 variable called EXTRALIBS, which appears in all the link commands, but by
2223 default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2224 command for linking the main Exim binary, and not for any associated utilities.
2226 .cindex "DBM libraries" "configuration for building"
2227 There is also DBMLIB, which appears in the link commands for binaries that
2228 use DBM functions (see also section &<<SECTdb>>&). Finally, there is
2229 EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2230 binary, and which can be used, for example, to include additional X11
2231 libraries.
2233 .cindex "configuration file" "editing"
2234 The make file copes with rebuilding Exim correctly if any of the configuration
2235 files are edited. However, if an optional configuration file is deleted, it is
2236 necessary to touch the associated non-optional file (that is,
2237 &_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
2240 .section "OS-specific header files" "SECID30"
2241 .cindex "&_os.h_&"
2242 .cindex "building Exim" "OS-specific C header files"
2243 The &_OS_& directory contains a number of files with names of the form
2244 &_os.h-<ostype>_&. These are system-specific C header files that should not
2245 normally need to be changed. There is a list of macro settings that are
2246 recognized in the file &_OS/os.configuring_&, which should be consulted if you
2247 are porting Exim to a new operating system.
2251 .section "Overriding build-time options for the monitor" "SECID31"
2252 .cindex "building Eximon"
2253 A similar process is used for overriding things when building the Exim monitor,
2254 where the files that are involved are
2255 .display
2256 &_OS/eximon.conf-Default_&
2257 &_OS/eximon.conf-_&<&'ostype'&>
2258 &_Local/eximon.conf_&
2259 &_Local/eximon.conf-_&<&'ostype'&>
2260 &_Local/eximon.conf-_&<&'archtype'&>
2261 &_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2262 .endd
2263 .cindex "&_Local/eximon.conf_&"
2264 As with Exim itself, the final three files need not exist, and in this case the
2265 &_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2266 &_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
2267 variables of the same name, preceded by EXIMON_. For example, setting
2268 EXIMON_LOG_DEPTH in the environment overrides the value of
2269 LOG_DEPTH at runtime.
2270 .ecindex IIDbuex
2273 .section "Installing Exim binaries and scripts" "SECID32"
2274 .cindex "installing Exim"
2275 .cindex "BIN_DIRECTORY"
2276 The command &`make install`& runs the &(exim_install)& script with no
2277 arguments. The script copies binaries and utility scripts into the directory
2278 whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2279 .cindex "setuid" "installing Exim with"
2280 The install script copies files only if they are newer than the files they are
2281 going to replace. The Exim binary is required to be owned by root and have the
2282 &'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2283 install`& as root so that it can set up the Exim binary in this way. However, in
2284 some special situations (for example, if a host is doing no local deliveries)
2285 it may be possible to run Exim without making the binary setuid root (see
2286 chapter &<<CHAPsecurity>>& for details).
2288 .cindex "CONFIGURE_FILE"
2289 Exim's runtime configuration file is named by the CONFIGURE_FILE setting
2290 in &_Local/Makefile_&. If this names a single file, and the file does not
2291 exist, the default configuration file &_src/configure.default_& is copied there
2292 by the installation script. If a runtime configuration file already exists, it
2293 is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2294 alternative files, no default is installed.
2296 .cindex "system aliases file"
2297 .cindex "&_/etc/aliases_&"
2298 One change is made to the default configuration file when it is installed: the
2299 default configuration contains a router that references a system aliases file.
2300 The path to this file is set to the value specified by
2301 SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
2302 If the system aliases file does not exist, the installation script creates it,
2303 and outputs a comment to the user.
2305 The created file contains no aliases, but it does contain comments about the
2306 aliases a site should normally have. Mail aliases have traditionally been
2307 kept in &_/etc/aliases_&. However, some operating systems are now using
2308 &_/etc/mail/aliases_&. You should check if yours is one of these, and change
2309 Exim's configuration if necessary.
2311 The default configuration uses the local host's name as the only local domain,
2312 and is set up to do local deliveries into the shared directory &_/var/mail_&,
2313 running as the local user. System aliases and &_.forward_& files in users' home
2314 directories are supported, but no NIS or NIS+ support is configured. Domains
2315 other than the name of the local host are routed using the DNS, with delivery
2316 over SMTP.
2318 It is possible to install Exim for special purposes (such as building a binary
2319 distribution) in a private part of the file system. You can do this by a
2320 command such as
2321 .code
2322 make DESTDIR=/some/directory/ install
2323 .endd
2324 This has the effect of pre-pending the specified directory to all the file
2325 paths, except the name of the system aliases file that appears in the default
2326 configuration. (If a default alias file is created, its name &'is'& modified.)
2327 For backwards compatibility, ROOT is used if DESTDIR is not set,
2328 but this usage is deprecated.
2330 .cindex "installing Exim" "what is not installed"
2331 Running &'make install'& does not copy the Exim 4 conversion script
2332 &'convert4r4'&. You will probably run this only once if you are
2333 upgrading from Exim 3. None of the documentation files in the &_doc_&
2334 directory are copied, except for the info files when you have set
2335 INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
2337 For the utility programs, old versions are renamed by adding the suffix &_.O_&
2338 to their names. The Exim binary itself, however, is handled differently. It is
2339 installed under a name that includes the version number and the compile number,
2340 for example, &_exim-&version()-1_&. The script then arranges for a symbolic link
2341 called &_exim_& to point to the binary. If you are updating a previous version
2342 of Exim, the script takes care to ensure that the name &_exim_& is never absent
2343 from the directory (as seen by other processes).
2345 .cindex "installing Exim" "testing the script"
2346 If you want to see what the &'make install'& will do before running it for
2347 real, you can pass the &%-n%& option to the installation script by this
2348 command:
2349 .code
2350 make INSTALL_ARG=-n install
2351 .endd
2352 The contents of the variable INSTALL_ARG are passed to the installation
2353 script. You do not need to be root to run this test. Alternatively, you can run
2354 the installation script directly, but this must be from within the build
2355 directory. For example, from the top-level Exim directory you could use this
2356 command:
2357 .code
2358 (cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2359 .endd
2360 .cindex "installing Exim" "install script options"
2361 There are two other options that can be supplied to the installation script.
2363 .ilist
2364 &%-no_chown%& bypasses the call to change the owner of the installed binary
2365 to root, and the call to make it a setuid binary.
2366 .next
2367 &%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
2368 installed binary.
2369 .endlist
2371 INSTALL_ARG can be used to pass these options to the script. For example:
2372 .code
2373 make INSTALL_ARG=-no_symlink install
2374 .endd
2375 The installation script can also be given arguments specifying which files are
2376 to be copied. For example, to install just the Exim binary, and nothing else,
2377 without creating the symbolic link, you could use:
2378 .code
2379 make INSTALL_ARG='-no_symlink exim' install
2380 .endd
2384 .section "Installing info documentation" "SECTinsinfdoc"
2385 .cindex "installing Exim" "&'info'& documentation"
2386 Not all systems use the GNU &'info'& system for documentation, and for this
2387 reason, the Texinfo source of Exim's documentation is not included in the main
2388 distribution. Instead it is available separately from the FTP site (see section
2389 &<<SECTavail>>&).
2391 If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2392 source of the documentation is found in the source tree, running &`make
2393 install`& automatically builds the info files and installs them.
2397 .section "Setting up the spool directory" "SECID33"
2398 .cindex "spool directory" "creating"
2399 When it starts up, Exim tries to create its spool directory if it does not
2400 exist. The Exim uid and gid are used for the owner and group of the spool
2401 directory. Sub-directories are automatically created in the spool directory as
2402 necessary.
2407 .section "Testing" "SECID34"
2408 .cindex "testing" "installation"
2409 Having installed Exim, you can check that the runtime configuration file is
2410 syntactically valid by running the following command, which assumes that the
2411 Exim binary directory is within your PATH environment variable:
2412 .code
2413 exim -bV
2414 .endd
2415 If there are any errors in the configuration file, Exim outputs error messages.
2416 Otherwise it outputs the version number and build date,
2417 the DBM library that is being used, and information about which drivers and
2418 other optional code modules are included in the binary.
2419 Some simple routing tests can be done by using the address testing option. For
2420 example,
2421 .display
2422 &`exim -bt`& <&'local username'&>
2423 .endd
2424 should verify that it recognizes a local mailbox, and
2425 .display
2426 &`exim -bt`& <&'remote address'&>
2427 .endd
2428 a remote one. Then try getting it to deliver mail, both locally and remotely.
2429 This can be done by passing messages directly to Exim, without going through a
2430 user agent. For example:
2431 .code
2432 exim -v postmaster@your.domain.example
2433 From: user@your.domain.example
2434 To: postmaster@your.domain.example
2435 Subject: Testing Exim
2437 This is a test message.
2438 ^D
2439 .endd
2440 The &%-v%& option causes Exim to output some verification of what it is doing.
2441 In this case you should see copies of three log lines, one for the message's
2442 arrival, one for its delivery, and one containing &"Completed"&.
2444 .cindex "delivery" "problems with"
2445 If you encounter problems, look at Exim's log files (&'mainlog'& and
2446 &'paniclog'&) to see if there is any relevant information there. Another source
2447 of information is running Exim with debugging turned on, by specifying the
2448 &%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
2449 with debugging turned on by a command of the form
2450 .display
2451 &`exim -d -M`& <&'exim-message-id'&>
2452 .endd
2453 You must be root or an &"admin user"& in order to do this. The &%-d%& option
2454 produces rather a lot of output, but you can cut this down to specific areas.
2455 For example, if you use &%-d-all+route%& only the debugging information
2456 relevant to routing is included. (See the &%-d%& option in chapter
2457 &<<CHAPcommandline>>& for more details.)
2459 .cindex '&"sticky"& bit'
2460 .cindex "lock files"
2461 One specific problem that has shown up on some sites is the inability to do
2462 local deliveries into a shared mailbox directory, because it does not have the
2463 &"sticky bit"& set on it. By default, Exim tries to create a lock file before
2464 writing to a mailbox file, and if it cannot create the lock file, the delivery
2465 is deferred. You can get round this either by setting the &"sticky bit"& on the
2466 directory, or by setting a specific group for local deliveries and allowing
2467 that group to create files in the directory (see the comments above the
2468 &(local_delivery)& transport in the default configuration file). Another
2469 approach is to configure Exim not to use lock files, but just to rely on
2470 &[fcntl()]& locking instead. However, you should do this only if all user
2471 agents also use &[fcntl()]& locking. For further discussion of locking issues,
2472 see chapter &<<CHAPappendfile>>&.
2474 One thing that cannot be tested on a system that is already running an MTA is
2475 the receipt of incoming SMTP mail on the standard SMTP port. However, the
2476 &%-oX%& option can be used to run an Exim daemon that listens on some other
2477 port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2478 &'exim_checkaccess'& utility can be used to check out policy controls on
2479 incoming SMTP mail.
2481 Testing a new version on a system that is already running Exim can most easily
2482 be done by building a binary with a different CONFIGURE_FILE setting. From
2483 within the runtime configuration, all other file and directory names
2484 that Exim uses can be altered, in order to keep it entirely clear of the
2485 production version.
2488 .section "Replacing another MTA with Exim" "SECID35"
2489 .cindex "replacing another MTA"
2490 Building and installing Exim for the first time does not of itself put it in
2491 general use. The name by which the system's MTA is called by mail user agents
2492 is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2493 operating system), and it is necessary to make this name point to the &'exim'&
2494 binary in order to get the user agents to pass messages to Exim. This is
2495 normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2496 or &_/usr/lib/sendmail_&
2497 .cindex "symbolic link" "to &'exim'& binary"
2498 a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
2499 privilege and executable status from the old MTA. It is then necessary to stop
2500 and restart the mailer daemon, if one is running.
2502 .cindex "FreeBSD, MTA indirection"
2503 .cindex "&_/etc/mail/mailer.conf_&"
2504 Some operating systems have introduced alternative ways of switching MTAs. For
2505 example, if you are running FreeBSD, you need to edit the file
2506 &_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
2507 described. A typical example of the contents of this file for running Exim is
2508 as follows:
2509 .code
2510 sendmail /usr/exim/bin/exim
2511 send-mail /usr/exim/bin/exim
2512 mailq /usr/exim/bin/exim -bp
2513 newaliases /usr/bin/true
2514 .endd
2515 Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2516 your Exim installation is &"live"&. Check it by sending a message from your
2517 favourite user agent.
2519 You should consider what to tell your users about the change of MTA. Exim may
2520 have different capabilities to what was previously running, and there are
2521 various operational differences such as the text of messages produced by
2522 command line options and in bounce messages. If you allow your users to make
2523 use of Exim's filtering capabilities, you should make the document entitled
2524 &'Exim's interface to mail filtering'& available to them.
2528 .section "Upgrading Exim" "SECID36"
2529 .cindex "upgrading Exim"
2530 If you are already running Exim on your host, building and installing a new
2531 version automatically makes it available to MUAs, or any other programs that
2532 call the MTA directly. However, if you are running an Exim daemon, you do need
2533 to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2534 new binary. You do not need to stop processing mail in order to install a new
2535 version of Exim. The install script does not modify an existing runtime
2536 configuration file.
2541 .section "Stopping the Exim daemon on Solaris" "SECID37"
2542 .cindex "Solaris" "stopping Exim on"
2543 The standard command for stopping the mailer daemon on Solaris is
2544 .code
2545 /etc/init.d/sendmail stop
2546 .endd
2547 If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2548 fails to stop Exim because it uses the command &'ps -e'& and greps the output
2549 for the text &"sendmail"&; this is not present because the actual program name
2550 (that is, &"exim"&) is given by the &'ps'& command with these options. A
2551 solution is to replace the line that finds the process id with something like
2552 .code
2553 pid=`cat /var/spool/exim/exim-daemon.pid`
2554 .endd
2555 to obtain the daemon's pid directly from the file that Exim saves it in.
2557 Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
2558 still be received from local processes, and if automatic delivery is configured
2559 (the normal case), deliveries will still occur.
2564 . ////////////////////////////////////////////////////////////////////////////
2565 . ////////////////////////////////////////////////////////////////////////////
2567 .chapter "The Exim command line" "CHAPcommandline"
2568 .scindex IIDclo1 "command line" "options"
2569 .scindex IIDclo2 "options" "command line"
2570 Exim's command line takes the standard Unix form of a sequence of options,
2571 each starting with a hyphen character, followed by a number of arguments. The
2572 options are compatible with the main options of Sendmail, and there are also
2573 some additional options, some of which are compatible with Smail 3. Certain
2574 combinations of options do not make sense, and provoke an error if used.
2575 The form of the arguments depends on which options are set.
2578 .section "Setting options by program name" "SECID38"
2579 .cindex "&'mailq'&"
2580 If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
2581 were present before any other options.
2582 The &%-bp%& option requests a listing of the contents of the mail queue on the
2583 standard output.
2584 This feature is for compatibility with some systems that contain a command of
2585 that name in one of the standard libraries, symbolically linked to
2586 &_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2588 .cindex "&'rsmtp'&"
2589 If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2590 were present before any other options, for compatibility with Smail. The
2591 &%-bS%& option is used for reading in a number of messages in batched SMTP
2592 format.
2594 .cindex "&'rmail'&"
2595 If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2596 &%-oee%& options were present before any other options, for compatibility with
2597 Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2599 .cindex "&'runq'&"
2600 .cindex "queue runner"
2601 If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2602 were present before any other options, for compatibility with Smail. The &%-q%&
2603 option causes a single queue runner process to be started.
2605 .cindex "&'newaliases'&"
2606 .cindex "alias file" "building"
2607 .cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2608 If Exim is called under the name &'newaliases'& it behaves as if the option
2609 &%-bi%& were present before any other options, for compatibility with Sendmail.
2610 This option is used for rebuilding Sendmail's alias file. Exim does not have
2611 the concept of a single alias file, but can be configured to run a given
2612 command if called with the &%-bi%& option.
2615 .section "Trusted and admin users" "SECTtrustedadmin"
2616 Some Exim options are available only to &'trusted users'& and others are
2617 available only to &'admin users'&. In the description below, the phrases &"Exim
2618 user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2619 EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2620 &%exim_group%& options. These do not necessarily have to use the name &"exim"&.
2622 .ilist
2623 .cindex "trusted users" "definition of"
2624 .cindex "user" "trusted definition of"
2625 The trusted users are root, the Exim user, any user listed in the
2626 &%trusted_users%& configuration option, and any user whose current group or any
2627 supplementary group is one of those listed in the &%trusted_groups%&
2628 configuration option. Note that the Exim group is not automatically trusted.
2630 .cindex '&"From"& line'
2631 .cindex "envelope sender"
2632 Trusted users are always permitted to use the &%-f%& option or a leading
2633 &"From&~"& line to specify the envelope sender of a message that is passed to
2634 Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2635 See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2636 users to set envelope senders.
2638 .cindex "&'From:'& header line"
2639 .cindex "&'Sender:'& header line"
2640 .cindex "header lines" "From:"
2641 .cindex "header lines" "Sender:"
2642 For a trusted user, there is never any check on the contents of the &'From:'&
2643 header line, and a &'Sender:'& line is never added. Furthermore, any existing
2644 &'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2646 Trusted users may also specify a host name, host address, interface address,
2647 protocol name, ident value, and authentication data when submitting a message
2648 locally. Thus, they are able to insert messages into Exim's queue locally that
2649 have the characteristics of messages received from a remote host. Untrusted
2650 users may in some circumstances use &%-f%&, but can never set the other values
2651 that are available to trusted users.
2652 .next
2653 .cindex "user" "admin definition of"
2654 .cindex "admin user" "definition of"
2655 The admin users are root, the Exim user, and any user that is a member of the
2656 Exim group or of any group listed in the &%admin_groups%& configuration option.
2657 The current group does not have to be one of these groups.
2659 Admin users are permitted to list the queue, and to carry out certain
2660 operations on messages, for example, to force delivery failures. It is also
2661 necessary to be an admin user in order to see the full information provided by
2662 the Exim monitor, and full debugging output.
2664 By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2665 Exim to attempt delivery of messages on its queue is restricted to admin users.
2666 However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2667 option false (that is, specifying &%no_prod_requires_admin%&).
2669 Similarly, the use of the &%-bp%& option to list all the messages in the queue
2670 is restricted to admin users unless &%queue_list_requires_admin%& is set
2671 false.
2672 .endlist
2675 &*Warning*&: If you configure your system so that admin users are able to
2676 edit Exim's configuration file, you are giving those users an easy way of
2677 getting root. There is further discussion of this issue at the start of chapter
2678 &<<CHAPconf>>&.
2683 .section "Command line options" "SECID39"
2684 Exim's command line options are described in alphabetical order below. If none
2685 of the options that specifies a specific action (such as starting the daemon or
2686 a queue runner, or testing an address, or receiving a message in a specific
2687 format, or listing the queue) are present, and there is at least one argument
2688 on the command line, &%-bm%& (accept a local message on the standard input,
2689 with the arguments specifying the recipients) is assumed. Otherwise, Exim
2690 outputs a brief message about itself and exits.
2692 . ////////////////////////////////////////////////////////////////////////////
2693 . Insert a stylized XML comment here, to identify the start of the command line
2694 . options. This is for the benefit of the Perl script that automatically
2695 . creates a man page for the options.
2696 . ////////////////////////////////////////////////////////////////////////////
2698 .literal xml
2699 <!-- === Start of command line options === -->
2700 .literal off
2703 .vlist
2704 .vitem &%--%&
2705 .oindex "--"
2706 .cindex "options" "command line; terminating"
2707 This is a pseudo-option whose only purpose is to terminate the options and
2708 therefore to cause subsequent command line items to be treated as arguments
2709 rather than options, even if they begin with hyphens.
2711 .vitem &%--help%&
2712 .oindex "&%--help%&"
2713 This option causes Exim to output a few sentences stating what it is.
2714 The same output is generated if the Exim binary is called with no options and
2715 no arguments.
2717 .vitem &%--version%&
2718 .oindex "&%--version%&"
2719 This option is an alias for &%-bV%& and causes version information to be
2720 displayed.
2722 .vitem &%-Ac%& &&&
2723 &%-Am%&
2724 .oindex "&%-Ac%&"
2725 .oindex "&%-Am%&"
2726 These options are used by Sendmail for selecting configuration files and are
2727 ignored by Exim.
2729 .vitem &%-B%&<&'type'&>
2730 .oindex "&%-B%&"
2731 .cindex "8-bit characters"
2732 .cindex "Sendmail compatibility" "8-bit characters"
2733 This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2734 clean; it ignores this option.
2736 .vitem &%-bd%&
2737 .oindex "&%-bd%&"
2738 .cindex "daemon"
2739 .cindex "SMTP" "listener"
2740 .cindex "queue runner"
2741 This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
2742 the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2743 that the daemon should also initiate periodic queue runs.
2745 The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2746 (debugging) or &%-v%& (verifying) options are set, the daemon does not
2747 disconnect from the controlling terminal. When running this way, it can be
2748 stopped by pressing ctrl-C.
2750 By default, Exim listens for incoming connections to the standard SMTP port on
2751 all the host's running interfaces. However, it is possible to listen on other
2752 ports, on multiple ports, and only on specific interfaces. Chapter
2753 &<<CHAPinterfaces>>& contains a description of the options that control this.
2755 When a listening daemon
2756 .cindex "daemon" "process id (pid)"
2757 .cindex "pid (process id)" "of daemon"
2758 is started without the use of &%-oX%& (that is, without overriding the normal
2759 configuration), it writes its process id to a file called &_exim-daemon.pid_&
2760 in Exim's spool directory. This location can be overridden by setting
2761 PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
2762 running as root.
2764 When &%-oX%& is used on the command line to start a listening daemon, the
2765 process id is not written to the normal pid file path. However, &%-oP%& can be
2766 used to specify a path on the command line if a pid file is required.
2768 The SIGHUP signal
2769 .cindex "SIGHUP"
2770 .cindex "daemon" "restarting"
2771 can be used to cause the daemon to re-execute itself. This should be done
2772 whenever Exim's configuration file, or any file that is incorporated into it by
2773 means of the &%.include%& facility, is changed, and also whenever a new version
2774 of Exim is installed. It is not necessary to do this when other files that are
2775 referenced from the configuration (for example, alias files) are changed,
2776 because these are reread each time they are used.
2778 .vitem &%-bdf%&
2779 .oindex "&%-bdf%&"
2780 This option has the same effect as &%-bd%& except that it never disconnects
2781 from the controlling terminal, even when no debugging is specified.
2783 .vitem &%-be%&
2784 .oindex "&%-be%&"
2785 .cindex "testing" "string expansion"
2786 .cindex "expansion" "testing"
2787 Run Exim in expansion testing mode. Exim discards its root privilege, to
2788 prevent ordinary users from using this mode to read otherwise inaccessible
2789 files. If no arguments are given, Exim runs interactively, prompting for lines
2790 of data. Otherwise, it processes each argument in turn.
2792 If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2793 to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2794 used without command line arguments. If successful, it uses the &[readline()]&
2795 function, which provides extensive line-editing facilities, for reading the
2796 test data. A line history is supported.
2798 Long expansion expressions can be split over several lines by using backslash
2799 continuations. As in Exim's runtime configuration, white space at the start of
2800 continuation lines is ignored. Each argument or data line is passed through the
2801 string expansion mechanism, and the result is output. Variable values from the
2802 configuration file (for example, &$qualify_domain$&) are available, but no
2803 message-specific values (such as &$message_exim_id$&) are set, because no message
2804 is being processed (but see &%-bem%& and &%-Mset%&).
2806 &*Note*&: If you use this mechanism to test lookups, and you change the data
2807 files or databases you are using, you must exit and restart Exim before trying
2808 the same lookup again. Otherwise, because each Exim process caches the results
2809 of lookups, you will just get the same result as before.
2811 Macro processing is done on lines before string-expansion: new macros can be
2812 defined and macros will be expanded.
2813 Because macros in the config file are often used for secrets, those are only
2814 available to admin users.
2816 .vitem &%-bem%&&~<&'filename'&>
2817 .oindex "&%-bem%&"
2818 .cindex "testing" "string expansion"
2819 .cindex "expansion" "testing"
2820 This option operates like &%-be%& except that it must be followed by the name
2821 of a file. For example:
2822 .code
2823 exim -bem /tmp/testmessage
2824 .endd
2825 The file is read as a message (as if receiving a locally-submitted non-SMTP
2826 message) before any of the test expansions are done. Thus, message-specific
2827 variables such as &$message_size$& and &$header_from:$& are available. However,
2828 no &'Received:'& header is added to the message. If the &%-t%& option is set,
2829 recipients are read from the headers in the normal way, and are shown in the
2830 &$recipients$& variable. Note that recipients cannot be given on the command
2831 line, because further arguments are taken as strings to expand (just like
2832 &%-be%&).
2834 .vitem &%-bF%&&~<&'filename'&>
2835 .oindex "&%-bF%&"
2836 .cindex "system filter" "testing"
2837 .cindex "testing" "system filter"
2838 This option is the same as &%-bf%& except that it assumes that the filter being
2839 tested is a system filter. The additional commands that are available only in
2840 system filters are recognized.
2842 .vitem &%-bf%&&~<&'filename'&>
2843 .oindex "&%-bf%&"
2844 .cindex "filter" "testing"
2845 .cindex "testing" "filter file"
2846 .cindex "forward file" "testing"
2847 .cindex "testing" "forward file"
2848 .cindex "Sieve filter" "testing"
2849 This option runs Exim in user filter testing mode; the file is the filter file
2850 to be tested, and a test message must be supplied on the standard input. If
2851 there are no message-dependent tests in the filter, an empty file can be
2852 supplied.
2854 If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2855 can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2856 filter and a user filter in the same run. For example:
2857 .code
2858 exim -bF /system/filter -bf /user/filter </test/message
2859 .endd
2860 This is helpful when the system filter adds header lines or sets filter
2861 variables that are used by the user filter.
2863 If the test filter file does not begin with one of the special lines
2864 .code
2865 # Exim filter
2866 # Sieve filter
2867 .endd
2868 it is taken to be a normal &_.forward_& file, and is tested for validity under
2869 that interpretation. See sections &<<SECTitenonfilred>>& to
2870 &<<SECTspecitredli>>& for a description of the possible contents of non-filter
2871 redirection lists.
2873 The result of an Exim command that uses &%-bf%&, provided no errors are
2874 detected, is a list of the actions that Exim would try to take if presented
2875 with the message for real. More details of filter testing are given in the
2876 separate document entitled &'Exim's interfaces to mail filtering'&.
2878 When testing a filter file,
2879 .cindex "&""From""& line"
2880 .cindex "envelope sender"
2881 .oindex "&%-f%&" "for filter testing"
2882 the envelope sender can be set by the &%-f%& option,
2883 or by a &"From&~"& line at the start of the test message. Various parameters
2884 that would normally be taken from the envelope recipient address of the message
2885 can be set by means of additional command line options (see the next four
2886 options).
2888 .vitem &%-bfd%&&~<&'domain'&>
2889 .oindex "&%-bfd%&"
2890 .vindex "&$qualify_domain$&"
2891 This sets the domain of the recipient address when a filter file is being
2892 tested by means of the &%-bf%& option. The default is the value of
2893 &$qualify_domain$&.
2895 .vitem &%-bfl%&&~<&'local&~part'&>
2896 .oindex "&%-bfl%&"
2897 This sets the local part of the recipient address when a filter file is being
2898 tested by means of the &%-bf%& option. The default is the username of the
2899 process that calls Exim. A local part should be specified with any prefix or
2900 suffix stripped, because that is how it appears to the filter when a message is
2901 actually being delivered.
2903 .vitem &%-bfp%&&~<&'prefix'&>
2904 .oindex "&%-bfp%&"
2905 .cindex affix "filter testing"
2906 This sets the prefix of the local part of the recipient address when a filter
2907 file is being tested by means of the &%-bf%& option. The default is an empty
2908 prefix.
2910 .vitem &%-bfs%&&~<&'suffix'&>
2911 .oindex "&%-bfs%&"
2912 .cindex affix "filter testing"
2913 This sets the suffix of the local part of the recipient address when a filter
2914 file is being tested by means of the &%-bf%& option. The default is an empty
2915 suffix.
2917 .vitem &%-bh%&&~<&'IP&~address'&>
2918 .oindex "&%-bh%&"
2919 .cindex "testing" "incoming SMTP"
2920 .cindex "SMTP" "testing incoming"
2921 .cindex "testing" "relay control"
2922 .cindex "relaying" "testing configuration"
2923 .cindex "policy control" "testing"
2924 .cindex "debugging" "&%-bh%& option"
2925 This option runs a fake SMTP session as if from the given IP address, using the
2926 standard input and output. The IP address may include a port number at the end,
2927 after a full stop. For example:
2928 .code
2929 exim -bh
2930 exim -bh fe80::a00:20ff:fe86:a061.5678
2931 .endd
2932 When an IPv6 address is given, it is converted into canonical form. In the case
2933 of the second example above, the value of &$sender_host_address$& after
2934 conversion to the canonical form is
2935 &`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2937 Comments as to what is going on are written to the standard error file. These
2938 include lines beginning with &"LOG"& for anything that would have been logged.
2939 This facility is provided for testing configuration options for incoming
2940 messages, to make sure they implement the required policy. For example, you can
2941 test your relay controls using &%-bh%&.
2943 &*Warning 1*&:
2944 .cindex "RFC 1413"
2945 You can test features of the configuration that rely on ident (RFC 1413)
2946 information by using the &%-oMt%& option. However, Exim cannot actually perform
2947 an ident callout when testing using &%-bh%& because there is no incoming SMTP
2948 connection.
2950 &*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2951 are also skipped when testing using &%-bh%&. If you want these callouts to
2952 occur, use &%-bhc%& instead.
2954 Messages supplied during the testing session are discarded, and nothing is
2955 written to any of the real log files. There may be pauses when DNS (and other)
2956 lookups are taking place, and of course these may time out. The &%-oMi%& option
2957 can be used to specify a specific IP interface and port if this is important,
2958 and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2959 session were authenticated.
2961 The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
2962 output just states whether a given recipient address from a given host is
2963 acceptable or not. See section &<<SECTcheckaccess>>&.
2965 Features such as authentication and encryption, where the client input is not
2966 plain text, cannot easily be tested with &%-bh%&. Instead, you should use a
2967 specialized SMTP test program such as
2968 &url(https://www.jetmore.org/john/code/swaks/,swaks).
2970 .vitem &%-bhc%&&~<&'IP&~address'&>
2971 .oindex "&%-bhc%&"
2972 This option operates in the same way as &%-bh%&, except that address
2973 verification callouts are performed if required. This includes consulting and
2974 updating the callout cache database.
2976 .vitem &%-bi%&
2977 .oindex "&%-bi%&"
2978 .cindex "alias file" "building"
2979 .cindex "building alias file"
2980 .cindex "Sendmail compatibility" "&%-bi%& option"
2981 Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
2982 Exim does not have the concept of a single alias file, and so it cannot mimic
2983 this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
2984 tend to appear in various scripts such as NIS make files, so the option must be
2985 recognized.
2987 If &%-bi%& is encountered, the command specified by the &%bi_command%&
2988 configuration option is run, under the uid and gid of the caller of Exim. If
2989 the &%-oA%& option is used, its value is passed to the command as an argument.
2990 The command set by &%bi_command%& may not contain arguments. The command can
2991 use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2992 if this is required. If the &%bi_command%& option is not set, calling Exim with
2993 &%-bi%& is a no-op.
2995 . // Keep :help first, then the rest in alphabetical order
2996 .vitem &%-bI:help%&
2997 .oindex "&%-bI:help%&"
2998 .cindex "querying exim information"
2999 We shall provide various options starting &`-bI:`& for querying Exim for
3000 information. The output of many of these will be intended for machine
3001 consumption. This one is not. The &%-bI:help%& option asks Exim for a
3002 synopsis of supported options beginning &`-bI:`&. Use of any of these
3003 options shall cause Exim to exit after producing the requested output.
3005 .vitem &%-bI:dscp%&
3006 .oindex "&%-bI:dscp%&"
3007 .cindex "DSCP" "values"
3008 This option causes Exim to emit an alphabetically sorted list of all
3009 recognised DSCP names.
3011 .vitem &%-bI:sieve%&
3012 .oindex "&%-bI:sieve%&"
3013 .cindex "Sieve filter" "capabilities"
3014 This option causes Exim to emit an alphabetically sorted list of all supported
3015 Sieve protocol extensions on stdout, one per line. This is anticipated to be
3016 useful for ManageSieve (RFC 5804) implementations, in providing that protocol's
3017 &`SIEVE`& capability response line. As the precise list may depend upon
3018 compile-time build options, which this option will adapt to, this is the only
3019 way to guarantee a correct response.
3021 .vitem &%-bm%&
3022 .oindex "&%-bm%&"
3023 .cindex "local message reception"
3024 This option runs an Exim receiving process that accepts an incoming,
3025 locally-generated message on the standard input. The recipients are given as the
3026 command arguments (except when &%-t%& is also present &-- see below). Each
3027 argument can be a comma-separated list of RFC 2822 addresses. This is the
3028 default option for selecting the overall action of an Exim call; it is assumed
3029 if no other conflicting option is present.
3031 If any addresses in the message are unqualified (have no domain), they are
3032 qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
3033 options, as appropriate. The &%-bnq%& option (see below) provides a way of
3034 suppressing this for special cases.
3036 Policy checks on the contents of local messages can be enforced by means of
3037 the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
3039 .cindex "return code" "for &%-bm%&"
3040 The return code is zero if the message is successfully accepted. Otherwise, the
3041 action is controlled by the &%-oe%&&'x'& option setting &-- see below.
3043 The format
3044 .cindex "message" "format"
3045 .cindex "format" "message"
3046 .cindex "&""From""& line"
3047 .cindex "UUCP" "&""From""& line"
3048 .cindex "Sendmail compatibility" "&""From""& line"
3049 of the message must be as defined in RFC 2822, except that, for
3050 compatibility with Sendmail and Smail, a line in one of the forms
3051 .code
3052 From sender Fri Jan 5 12:55 GMT 1997
3053 From sender Fri, 5 Jan 97 12:55:01
3054 .endd
3055 (with the weekday optional, and possibly with additional text after the date)
3056 is permitted to appear at the start of the message. There appears to be no
3057 authoritative specification of the format of this line. Exim recognizes it by
3058 matching against the regular expression defined by the &%uucp_from_pattern%&
3059 option, which can be changed if necessary.
3061 .oindex "&%-f%&" "overriding &""From""& line"
3062 The specified sender is treated as if it were given as the argument to the
3063 &%-f%& option, but if a &%-f%& option is also present, its argument is used in
3064 preference to the address taken from the message. The caller of Exim must be a
3065 trusted user for the sender of a message to be set in this way.
3067 .vitem &%-bmalware%&&~<&'filename'&>
3068 .oindex "&%-bmalware%&"
3069 .cindex "testing", "malware"
3070 .cindex "malware scan test"
3071 This debugging option causes Exim to scan the given file or directory
3072 (depending on the used scanner interface),
3073 using the malware scanning framework. The option of &%av_scanner%& influences
3074 this option, so if &%av_scanner%&'s value is dependent upon an expansion then
3075 the expansion should have defaults which apply to this invocation. ACLs are
3076 not invoked, so if &%av_scanner%& references an ACL variable then that variable
3077 will never be populated and &%-bmalware%& will fail.
3079 Exim will have changed working directory before resolving the filename, so
3080 using fully qualified pathnames is advisable. Exim will be running as the Exim
3081 user when it tries to open the file, rather than as the invoking user.
3082 This option requires admin privileges.
3084 The &%-bmalware%& option will not be extended to be more generally useful,
3085 there are better tools for file-scanning. This option exists to help
3086 administrators verify their Exim and AV scanner configuration.
3088 .vitem &%-bnq%&
3089 .oindex "&%-bnq%&"
3090 .cindex "address qualification, suppressing"
3091 By default, Exim automatically qualifies unqualified addresses (those
3092 without domains) that appear in messages that are submitted locally (that
3093 is, not over TCP/IP). This qualification applies both to addresses in
3094 envelopes, and addresses in header lines. Sender addresses are qualified using
3095 &%qualify_domain%&, and recipient addresses using &%qualify_recipient%& (which
3096 defaults to the value of &%qualify_domain%&).
3098 Sometimes, qualification is not wanted. For example, if &%-bS%& (batch SMTP) is
3099 being used to re-submit messages that originally came from remote hosts after
3100 content scanning, you probably do not want to qualify unqualified addresses in
3101 header lines. (Such lines will be present only if you have not enabled a header
3102 syntax check in the appropriate ACL.)
3104 The &%-bnq%& option suppresses all qualification of unqualified addresses in
3105 messages that originate on the local host. When this is used, unqualified
3106 addresses in the envelope provoke errors (causing message rejection) and
3107 unqualified addresses in header lines are left alone.
3110 .vitem &%-bP%&
3111 .oindex "&%-bP%&"
3112 .cindex "configuration options" "extracting"
3113 .cindex "options" "configuration &-- extracting"
3114 If this option is given with no arguments, it causes the values of all Exim's
3115 main configuration options to be written to the standard output. The values
3116 of one or more specific options can be requested by giving their names as
3117 arguments, for example:
3118 .code
3119 exim -bP qualify_domain hold_domains
3120 .endd
3121 .cindex "hiding configuration option values"
3122 .cindex "configuration options" "hiding value of"
3123 .cindex "options" "hiding value of"
3124 However, any option setting that is preceded by the word &"hide"& in the
3125 configuration file is not shown in full, except to an admin user. For other
3126 users, the output is as in this example:
3127 .code
3128 mysql_servers = <value not displayable>
3129 .endd
3130 If &%config%& is given as an argument, the config is
3131 output, as it was parsed, any include file resolved, any comment removed.
3133 If &%config_file%& is given as an argument, the name of the runtime
3134 configuration file is output. (&%configure_file%& works too, for
3135 backward compatibility.)
3136 If a list of configuration files was supplied, the value that is output here
3137 is the name of the file that was actually used.
3139 .cindex "options" "hiding name of"
3140 If the &%-n%& flag is given, then for most modes of &%-bP%& operation the
3141 name will not be output.
3143 .cindex "daemon" "process id (pid)"
3144 .cindex "pid (process id)" "of daemon"
3145 If &%log_file_path%& or &%pid_file_path%& are given, the names of the
3146 directories where log files and daemon pid files are written are output,
3147 respectively. If these values are unset, log files are written in a
3148 sub-directory of the spool directory called &%log%&, and the pid file is
3149 written directly into the spool directory.
3151 If &%-bP%& is followed by a name preceded by &`+`&, for example,
3152 .code
3153 exim -bP +local_domains
3154 .endd
3155 it searches for a matching named list of any type (domain, host, address, or
3156 local part) and outputs what it finds.
3158 .cindex "options" "router &-- extracting"
3159 .cindex "options" "transport &-- extracting"
3160 .cindex "options" "authenticator &-- extracting"
3161 If one of the words &%router%&, &%transport%&, or &%authenticator%& is given,
3162 followed by the name of an appropriate driver instance, the option settings for
3163 that driver are output. For example:
3164 .code
3165 exim -bP transport local_delivery
3166 .endd
3167 The generic driver options are output first, followed by the driver's private
3168 options. A list of the names of drivers of a particular type can be obtained by
3169 using one of the words &%router_list%&, &%transport_list%&, or
3170 &%authenticator_list%&, and a complete list of all drivers with their option
3171 settings can be obtained by using &%routers%&, &%transports%&, or
3172 &%authenticators%&.
3174 .cindex "environment"
3175 If &%environment%& is given as an argument, the set of environment
3176 variables is output, line by line. Using the &%-n%& flag suppresses the value of the
3177 variables.
3179 .cindex "options" "macro &-- extracting"
3180 If invoked by an admin user, then &%macro%&, &%macro_list%& and &%macros%&
3181 are available, similarly to the drivers. Because macros are sometimes used
3182 for storing passwords, this option is restricted.
3183 The output format is one item per line.
3184 For the "-bP macro <name>" form, if no such macro is found
3185 the exit status will be nonzero.
3187 .vitem &%-bp%&
3188 .oindex "&%-bp%&"
3189 .cindex "queue" "listing messages in"
3190 .cindex "listing" "messages in the queue"
3191 This option requests a listing of the contents of the mail queue on the
3192 standard output. If the &%-bp%& option is followed by a list of message ids,
3193 just those messages are listed. By default, this option can be used only by an
3194 admin user. However, the &%queue_list_requires_admin%& option can be set false
3195 to allow any user to see the queue.
3197 Each message in the queue is displayed as in the following example:
3198 .code
3199 25m 2.9K 0t5C6f-0000c8-00 <alice@wonderland.fict.example>
3200 red.king@looking-glass.fict.example
3201 <other addresses>
3202 .endd
3203 .cindex "message" "size in queue listing"
3204 .cindex "size" "of message"
3205 The first line contains the length of time the message has been in the queue
3206 (in this case 25 minutes), the size of the message (2.9K), the unique local
3207 identifier for the message, and the message sender, as contained in the
3208 envelope. For bounce messages, the sender address is empty, and appears as
3209 &"<>"&. If the message was submitted locally by an untrusted user who overrode
3210 the default sender address, the user's login name is shown in parentheses
3211 before the sender address.
3213 .cindex "frozen messages" "in queue listing"
3214 If the message is frozen (attempts to deliver it are suspended) then the text
3215 &"*** frozen ***"& is displayed at the end of this line.
3217 The recipients of the message (taken from the envelope, not the headers) are
3218 displayed on subsequent lines. Those addresses to which the message has already
3219 been delivered are marked with the letter D. If an original address gets
3220 expanded into several addresses via an alias or forward file, the original is
3221 displayed with a D only when deliveries for all of its child addresses are
3222 complete.
3225 .vitem &%-bpa%&
3226 .oindex "&%-bpa%&"
3227 This option operates like &%-bp%&, but in addition it shows delivered addresses
3228 that were generated from the original top level address(es) in each message by
3229 alias or forwarding operations. These addresses are flagged with &"+D"& instead
3230 of just &"D"&.
3233 .vitem &%-bpc%&
3234 .oindex "&%-bpc%&"
3235 .cindex "queue" "count of messages on"
3236 This option counts the number of messages in the queue, and writes the total
3237 to the standard output. It is restricted to admin users, unless
3238 &%queue_list_requires_admin%& is set false.
3241 .vitem &%-bpr%&
3242 .oindex "&%-bpr%&"
3243 This option operates like &%-bp%&, but the output is not sorted into
3244 chronological order of message arrival. This can speed it up when there are
3245 lots of messages in the queue, and is particularly useful if the output is
3246 going to be post-processed in a way that doesn't need the sorting.
3248 .vitem &%-bpra%&
3249 .oindex "&%-bpra%&"
3250 This option is a combination of &%-bpr%& and &%-bpa%&.
3252 .vitem &%-bpru%&
3253 .oindex "&%-bpru%&"
3254 This option is a combination of &%-bpr%& and &%-bpu%&.
3257 .vitem &%-bpu%&
3258 .oindex "&%-bpu%&"
3259 This option operates like &%-bp%& but shows only undelivered top-level
3260 addresses for each message displayed. Addresses generated by aliasing or
3261 forwarding are not shown, unless the message was deferred after processing by a
3262 router with the &%one_time%& option set.
3265 .vitem &%-brt%&
3266 .oindex "&%-brt%&"
3267 .cindex "testing" "retry configuration"
3268 .cindex "retry" "configuration testing"
3269 This option is for testing retry rules, and it must be followed by up to three
3270 arguments. It causes Exim to look for a retry rule that matches the values
3271 and to write it to the standard output. For example:
3272 .code
3273 exim -brt bach.comp.mus.example
3274 Retry rule: *.comp.mus.example F,2h,15m; F,4d,30m;
3275 .endd
3276 See chapter &<<CHAPretry>>& for a description of Exim's retry rules. The first
3277 argument, which is required, can be a complete address in the form
3278 &'local_part@domain'&, or it can be just a domain name. If the second argument
3279 contains a dot, it is interpreted as an optional second domain name; if no
3280 retry rule is found for the first argument, the second is tried. This ties in
3281 with Exim's behaviour when looking for retry rules for remote hosts &-- if no
3282 rule is found that matches the host, one that matches the mail domain is
3283 sought. Finally, an argument that is the name of a specific delivery error, as
3284 used in setting up retry rules, can be given. For example:
3285 .code
3286 exim -brt haydn.comp.mus.example quota_3d
3287 Retry rule: *@haydn.comp.mus.example quota_3d F,1h,15m
3288 .endd
3290 .vitem &%-brw%&
3291 .oindex "&%-brw%&"
3292 .cindex "testing" "rewriting"
3293 .cindex "rewriting" "testing"
3294 This option is for testing address rewriting rules, and it must be followed by
3295 a single argument, consisting of either a local part without a domain, or a
3296 complete address with a fully qualified domain. Exim outputs how this address
3297 would be rewritten for each possible place it might appear. See chapter
3298 &<<CHAPrewrite>>& for further details.
3300 .vitem &%-bS%&
3301 .oindex "&%-bS%&"
3302 .cindex "SMTP" "batched incoming"
3303 .cindex "batched SMTP input"
3304 This option is used for batched SMTP input, which is an alternative interface
3305 for non-interactive local message submission. A number of messages can be
3306 submitted in a single run. However, despite its name, this is not really SMTP
3307 input. Exim reads each message's envelope from SMTP commands on the standard
3308 input, but generates no responses. If the caller is trusted, or
3309 &%untrusted_set_sender%& is set, the senders in the SMTP MAIL commands are
3310 believed; otherwise the sender is always the caller of Exim.
3312 The message itself is read from the standard input, in SMTP format (leading
3313 dots doubled), terminated by a line containing just a single dot. An error is
3314 provoked if the terminating dot is missing. A further message may then follow.
3316 As for other local message submissions, the contents of incoming batch SMTP
3317 messages can be checked using the non-SMTP ACL (see chapter &<<CHAPACL>>&).
3318 Unqualified addresses are automatically qualified using &%qualify_domain%& and
3319 &%qualify_recipient%&, as appropriate, unless the &%-bnq%& option is used.
3321 Some other SMTP commands are recognized in the input. HELO and EHLO act
3322 as RSET; VRFY, EXPN, ETRN, and HELP act as NOOP;
3323 QUIT quits, ignoring the rest of the standard input.
3325 .cindex "return code" "for &%-bS%&"
3326 If any error is encountered, reports are written to the standard output and
3327 error streams, and Exim gives up immediately. The return code is 0 if no error
3328 was detected; it is 1 if one or more messages were accepted before the error
3329 was detected; otherwise it is 2.
3331 More details of input using batched SMTP are given in section
3332 &<<SECTincomingbatchedSMTP>>&.
3334 .vitem &%-bs%&
3335 .oindex "&%-bs%&"
3336 .cindex "SMTP" "local input"
3337 .cindex "local SMTP input"
3338 This option causes Exim to accept one or more messages by reading SMTP commands
3339 on the standard input, and producing SMTP replies on the standard output. SMTP
3340 policy controls, as defined in ACLs (see chapter &<<CHAPACL>>&) are applied.
3341 Some user agents use this interface as a way of passing locally-generated
3342 messages to the MTA.
3344 In
3345 .cindex "sender" "source of"
3346 this usage, if the caller of Exim is trusted, or &%untrusted_set_sender%& is
3347 set, the senders of messages are taken from the SMTP MAIL commands.
3348 Otherwise the content of these commands is ignored and the sender is set up as
3349 the calling user. Unqualified addresses are automatically qualified using
3350 &%qualify_domain%& and &%qualify_recipient%&, as appropriate, unless the
3351 &%-bnq%& option is used.
3353 .cindex "inetd"
3354 The
3355 &%-bs%& option is also used to run Exim from &'inetd'&, as an alternative to
3356 using a listening daemon. Exim can distinguish the two cases by checking
3357 whether the standard input is a TCP/IP socket. When Exim is called from
3358 &'inetd'&, the source of the mail is assumed to be remote, and the comments
3359 above concerning senders and qualification do not apply. In this situation,
3360 Exim behaves in exactly the same way as it does when receiving a message via
3361 the listening daemon.
3363 .vitem &%-bt%&
3364 .oindex "&%-bt%&"
3365 .cindex "testing" "addresses"
3366 .cindex "address" "testing"
3367 This option runs Exim in address testing mode, in which each argument is taken
3368 as a recipient address to be tested for deliverability. The results are
3369 written to the standard output. If a test fails, and the caller is not an admin
3370 user, no details of the failure are output, because these might contain
3371 sensitive information such as usernames and passwords for database lookups.
3373 If no arguments are given, Exim runs in an interactive manner, prompting with a
3374 right angle bracket for addresses to be tested.
3376 Unlike the &%-be%& test option, you cannot arrange for Exim to use the
3377 &[readline()]& function, because it is running as &'root'& and there are
3378 security issues.
3380 Each address is handled as if it were the recipient address of a message
3381 (compare the &%-bv%& option). It is passed to the routers and the result is
3382 written to the standard output. However, any router that has
3383 &%no_address_test%& set is bypassed. This can make &%-bt%& easier to use for
3384 genuine routing tests if your first router passes everything to a scanner
3385 program.
3387 .cindex "return code" "for &%-bt%&"
3388 The return code is 2 if any address failed outright; it is 1 if no address
3389 failed outright but at least one could not be resolved for some reason. Return
3390 code 0 is given only when all addresses succeed.
3392 .cindex "duplicate addresses"
3393 &*Note*&: When actually delivering a message, Exim removes duplicate recipient
3394 addresses after routing is complete, so that only one delivery takes place.
3395 This does not happen when testing with &%-bt%&; the full results of routing are
3396 always shown.
3398 &*Warning*&: &%-bt%& can only do relatively simple testing. If any of the
3399 routers in the configuration makes any tests on the sender address of a
3400 message,
3401 .oindex "&%-f%&" "for address testing"
3402 you can use the &%-f%& option to set an appropriate sender when running
3403 &%-bt%& tests. Without it, the sender is assumed to be the calling user at the
3404 default qualifying domain. However, if you have set up (for example) routers
3405 whose behaviour depends on the contents of an incoming message, you cannot test
3406 those conditions using &%-bt%&. The &%-N%& option provides a possible way of
3407 doing such tests.
3409 .vitem &%-bV%&
3410 .oindex "&%-bV%&"
3411 .cindex "version number of Exim"
3412 This option causes Exim to write the current version number, compilation
3413 number, and compilation date of the &'exim'& binary to the standard output.
3414 It also lists the DBM library that is being used, the optional modules (such as
3415 specific lookup types), the drivers that are included in the binary, and the
3416 name of the runtime configuration file that is in use.
3418 As part of its operation, &%-bV%& causes Exim to read and syntax check its
3419 configuration file. However, this is a static check only. It cannot check
3420 values that are to be expanded. For example, although a misspelt ACL verb is
3421 detected, an error in the verb's arguments is not. You cannot rely on &%-bV%&
3422 alone to discover (for example) all the typos in the configuration; some
3423 realistic testing is needed. The &%-bh%& and &%-N%& options provide more
3424 dynamic testing facilities.
3426 .vitem &%-bv%&
3427 .oindex "&%-bv%&"
3428 .cindex "verifying address" "using &%-bv%&"
3429 .cindex "address" "verification"
3430 This option runs Exim in address verification mode, in which each argument is
3431 taken as a recipient address to be verified by the routers. (This does
3432 not involve any verification callouts). During normal operation, verification
3433 happens mostly as a consequence processing a &%verify%& condition in an ACL
3434 (see chapter &<<CHAPACL>>&). If you want to test an entire ACL, possibly
3435 including callouts, see the &%-bh%& and &%-bhc%& options.
3437 If verification fails, and the caller is not an admin user, no details of the
3438 failure are output, because these might contain sensitive information such as
3439 usernames and passwords for database lookups.
3441 If no arguments are given, Exim runs in an interactive manner, prompting with a
3442 right angle bracket for addresses to be verified.
3444 Unlike the &%-be%& test option, you cannot arrange for Exim to use the
3445 &[readline()]& function, because it is running as &'exim'& and there are
3446 security issues.
3448 Verification differs from address testing (the &%-bt%& option) in that routers
3449 that have &%no_verify%& set are skipped, and if the address is accepted by a
3450 router that has &%fail_verify%& set, verification fails. The address is
3451 verified as a recipient if &%-bv%& is used; to test verification for a sender
3452 address, &%-bvs%& should be used.
3454 If the &%-v%& option is not set, the output consists of a single line for each
3455 address, stating whether it was verified or not, and giving a reason in the
3456 latter case. Without &%-v%&, generating more than one address by redirection
3457 causes verification to end successfully, without considering the generated
3458 addresses. However, if just one address is generated, processing continues,
3459 and the generated address must verify successfully for the overall verification
3460 to succeed.
3462 When &%-v%& is set, more details are given of how the address has been handled,
3463 and in the case of address redirection, all the generated addresses are also
3464 considered. Verification may succeed for some and fail for others.
3466 The
3467 .cindex "return code" "for &%-bv%&"
3468 return code is 2 if any address failed outright; it is 1 if no address
3469 failed outright but at least one could not be resolved for some reason. Return
3470 code 0 is given only when all addresses succeed.
3472 If any of the routers in the configuration makes any tests on the sender
3473 address of a message, you should use the &%-f%& option to set an appropriate
3474 sender when running &%-bv%& tests. Without it, the sender is assumed to be the
3475 calling user at the default qualifying domain.
3477 .vitem &%-bvs%&
3478 .oindex "&%-bvs%&"
3479 This option acts like &%-bv%&, but verifies the address as a sender rather
3480 than a recipient address. This affects any rewriting and qualification that
3481 might happen.
3483 .vitem &%-bw%&
3484 .oindex "&%-bw%&"
3485 .cindex "daemon"
3486 .cindex "inetd"
3487 .cindex "inetd" "wait mode"
3488 This option runs Exim as a daemon, awaiting incoming SMTP connections,
3489 similarly to the &%-bd%& option. All port specifications on the command-line
3490 and in the configuration file are ignored. Queue-running may not be specified.
3492 In this mode, Exim expects to be passed a socket as fd 0 (stdin) which is
3493 listening for connections. This permits the system to start up and have
3494 inetd (or equivalent) listen on the SMTP ports, starting an Exim daemon for
3495 each port only when the first connection is received.
3497 If the option is given as &%-bw%&<&'time'&> then the time is a timeout, after
3498 which the daemon will exit, which should cause inetd to listen once more.
3500 .vitem &%-C%&&~<&'filelist'&>
3501 .oindex "&%-C%&"
3502 .cindex "configuration file" "alternate"
3503 .cindex "CONFIGURE_FILE"
3504 .cindex "alternate configuration file"
3505 This option causes Exim to find the runtime configuration file from the given
3506 list instead of from the list specified by the CONFIGURE_FILE
3507 compile-time setting. Usually, the list will consist of just a single filename,
3508 but it can be a colon-separated list of names. In this case, the first
3509 file that exists is used. Failure to open an existing file stops Exim from
3510 proceeding any further along the list, and an error is generated.
3512 When this option is used by a caller other than root, and the list is different
3513 from the compiled-in list, Exim gives up its root privilege immediately, and
3514 runs with the real and effective uid and gid set to those of the caller.
3515 However, if a TRUSTED_CONFIG_LIST file is defined in &_Local/Makefile_&, that
3516 file contains a list of full pathnames, one per line, for configuration files
3517 which are trusted. Root privilege is retained for any configuration file so
3518 listed, as long as the caller is the Exim user (or the user specified in the
3519 CONFIGURE_OWNER option, if any), and as long as the configuration file is
3520 not writeable by inappropriate users or groups.
3522 Leaving TRUSTED_CONFIG_LIST unset precludes the possibility of testing a
3523 configuration using &%-C%& right through message reception and delivery,
3524 even if the caller is root. The reception works, but by that time, Exim is
3525 running as the Exim user, so when it re-executes to regain privilege for the
3526 delivery, the use of &%-C%& causes privilege to be lost. However, root can
3527 test reception and delivery using two separate commands (one to put a message
3528 in the queue, using &%-odq%&, and another to do the delivery, using &%-M%&).
3530 If ALT_CONFIG_PREFIX is defined &_in Local/Makefile_&, it specifies a
3531 prefix string with which any file named in a &%-C%& command line option
3532 must start. In addition, the filename must not contain the sequence &`/../`&.
3533 However, if the value of the &%-C%& option is identical to the value of
3534 CONFIGURE_FILE in &_Local/Makefile_&, Exim ignores &%-C%& and proceeds as
3535 usual. There is no default setting for ALT_CONFIG_PREFIX; when it is
3536 unset, any filename can be used with &%-C%&.
3538 ALT_CONFIG_PREFIX can be used to confine alternative configuration files
3539 to a directory to which only root has access. This prevents someone who has
3540 broken into the Exim account from running a privileged Exim with an arbitrary
3541 configuration file.
3543 The &%-C%& facility is useful for ensuring that configuration files are
3544 syntactically correct, but cannot be used for test deliveries, unless the
3545 caller is privileged, or unless it is an exotic configuration that does not
3546 require privilege. No check is made on the owner or group of the files
3547 specified by this option.
3550 .vitem &%-D%&<&'macro'&>=<&'value'&>
3551 .oindex "&%-D%&"
3552 .cindex "macro" "setting on command line"
3553 This option can be used to override macro definitions in the configuration file
3554 (see section &<<SECTmacrodefs>>&). However, like &%-C%&, if it is used by an
3555 unprivileged caller, it causes Exim to give up its root privilege.
3556 If DISABLE_D_OPTION is defined in &_Local/Makefile_&, the use of &%-D%& is
3557 completely disabled, and its use causes an immediate error exit.
3559 If WHITELIST_D_MACROS is defined in &_Local/Makefile_& then it should be a
3560 colon-separated list of macros which are considered safe and, if &%-D%& only
3561 supplies macros from this list, and the values are acceptable, then Exim will
3562 not give up root privilege if the caller is root, the Exim run-time user, or
3563 the CONFIGURE_OWNER, if set. This is a transition mechanism and is expected
3564 to be removed in the future. Acceptable values for the macros satisfy the
3565 regexp: &`^[A-Za-z0-9_/.-]*$`&
3567 The entire option (including equals sign if present) must all be within one
3568 command line item. &%-D%& can be used to set the value of a macro to the empty
3569 string, in which case the equals sign is optional. These two commands are
3570 synonymous:
3571 .code
3572 exim -DABC ...
3573 exim -DABC= ...
3574 .endd
3575 To include spaces in a macro definition item, quotes must be used. If you use
3576 quotes, spaces are permitted around the macro name and the equals sign. For
3577 example:
3578 .code
3579 exim '-D ABC = something' ...
3580 .endd
3581 &%-D%& may be repeated up to 10 times on a command line.
3582 Only macro names up to 22 letters long can be set.
3585 .vitem &%-d%&<&'debug&~options'&>
3586 .oindex "&%-d%&"
3587 .cindex "debugging" "list of selectors"
3588 .cindex "debugging" "&%-d%& option"
3589 This option causes debugging information to be written to the standard
3590 error stream. It is restricted to admin users because debugging output may show
3591 database queries that contain password information. Also, the details of users'
3592 filter files should be protected. If a non-admin user uses &%-d%&, Exim
3593 writes an error message to the standard error stream and exits with a non-zero
3594 return code.
3596 When &%-d%& is used, &%-v%& is assumed. If &%-d%& is given on its own, a lot of
3597 standard debugging data is output. This can be reduced, or increased to include
3598 some more rarely needed information, by directly following &%-d%& with a string
3599 made up of names preceded by plus or minus characters. These add or remove sets
3600 of debugging data, respectively. For example, &%-d+filter%& adds filter
3601 debugging, whereas &%-d-all+filter%& selects only filter debugging. Note that
3602 no spaces are allowed in the debug setting. The available debugging categories
3603 are:
3604 .display
3605 &`acl `& ACL interpretation
3606 &`auth `& authenticators
3607 &`deliver `& general delivery logic
3608 &`dns `& DNS lookups (see also resolver)
3609 &`dnsbl `& DNS black list (aka RBL) code
3610 &`exec `& arguments for &[execv()]& calls
3611 &`expand `& detailed debugging for string expansions
3612 &`filter `& filter handling
3613 &`hints_lookup `& hints data lookups
3614 &`host_lookup `& all types of name-to-IP address handling
3615 &`ident `& ident lookup
3616 &`interface `& lists of local interfaces
3617 &`lists `& matching things in lists
3618 &`load `& system load checks
3619 &`local_scan `& can be used by &[local_scan()]& (see chapter &&&
3620 &<<CHAPlocalscan>>&)
3621 &`lookup `& general lookup code and all lookups
3622 &`memory `& memory handling
3623 &`noutf8 `& modifier: avoid UTF-8 line-drawing
3624 &`pid `& modifier: add pid to debug output lines
3625 &`process_info `& setting info for the process log
3626 &`queue_run `& queue runs
3627 &`receive `& general message reception logic
3628 &`resolver `& turn on the DNS resolver's debugging output
3629 &`retry `& retry handling
3630 &`rewrite `& address rewriting
3631 &`route `& address routing
3632 &`timestamp `& modifier: add timestamp to debug output lines
3633 &`tls `& TLS logic
3634 &`transport `& transports
3635 &`uid `& changes of uid/gid and looking up uid/gid
3636 &`verify `& address verification logic
3637 &`all `& almost all of the above (see below), and also &%-v%&
3638 .endd
3639 The &`all`& option excludes &`memory`& when used as &`+all`&, but includes it
3640 for &`-all`&. The reason for this is that &`+all`& is something that people
3641 tend to use when generating debug output for Exim maintainers. If &`+memory`&
3642 is included, an awful lot of output that is very rarely of interest is
3643 generated, so it now has to be explicitly requested. However, &`-all`& does
3644 turn everything off.
3646 .cindex "resolver, debugging output"
3647 .cindex "DNS resolver, debugging output"
3648 The &`resolver`& option produces output only if the DNS resolver was compiled
3649 with DEBUG enabled. This is not the case in some operating systems. Also,
3650 unfortunately, debugging output from the DNS resolver is written to stdout
3651 rather than stderr.
3653 The default (&%-d%& with no argument) omits &`expand`&, &`filter`&,
3654 &`interface`&, &`load`&, &`memory`&, &`pid`&, &`resolver`&, and &`timestamp`&.
3655 However, the &`pid`& selector is forced when debugging is turned on for a
3656 daemon, which then passes it on to any re-executed Exims. Exim also
3657 automatically adds the pid to debug lines when several remote deliveries are
3658 run in parallel.
3660 The &`timestamp`& selector causes the current time to be inserted at the start
3661 of all debug output lines. This can be useful when trying to track down delays
3662 in processing.
3664 .new
3665 .cindex debugging "UTF-8 in"
3666 .cindex UTF-8 "in debug output"
3667 The &`noutf8`& selector disables the use of
3668 UTF-8 line-drawing characters to group related information.
3669 When disabled. ascii-art is used instead.
3670 Using the &`+all`& option does not set this modifier,
3671 .wen
3673 If the &%debug_print%& option is set in any driver, it produces output whenever
3674 any debugging is selected, or if &%-v%& is used.
3676 .vitem &%-dd%&<&'debug&~options'&>
3677 .oindex "&%-dd%&"
3678 This option behaves exactly like &%-d%& except when used on a command that
3679 starts a daemon process. In that case, debugging is turned off for the
3680 subprocesses that the daemon creates. Thus, it is useful for monitoring the
3681 behaviour of the daemon without creating as much output as full debugging does.
3683 .vitem &%-dropcr%&
3684 .oindex "&%-dropcr%&"
3685 This is an obsolete option that is now a no-op. It used to affect the way Exim
3686 handled CR and LF characters in incoming messages. What happens now is
3687 described in section &<<SECTlineendings>>&.
3689 .vitem &%-E%&
3690 .oindex "&%-E%&"
3691 .cindex "bounce message" "generating"
3692 This option specifies that an incoming message is a locally-generated delivery
3693 failure report. It is used internally by Exim when handling delivery failures
3694 and is not intended for external use. Its only effect is to stop Exim
3695 generating certain messages to the postmaster, as otherwise message cascades
3696 could occur in some situations. As part of the same option, a message id may
3697 follow the characters &%-E%&. If it does, the log entry for the receipt of the
3698 new message contains the id, following &"R="&, as a cross-reference.
3700 .vitem &%-e%&&'x'&
3701 .oindex "&%-e%&&'x'&"
3702 There are a number of Sendmail options starting with &%-oe%& which seem to be
3703 called by various programs without the leading &%o%& in the option. For
3704 example, the &%vacation%& program uses &%-eq%&. Exim treats all options of the
3705 form &%-e%&&'x'& as synonymous with the corresponding &%-oe%&&'x'& options.
3707 .vitem &%-F%&&~<&'string'&>
3708 .oindex "&%-F%&"
3709 .cindex "sender" "name"
3710 .cindex "name" "of sender"
3711 This option sets the sender's full name for use when a locally-generated
3712 message is being accepted. In the absence of this option, the user's &'gecos'&
3713 entry from the password data is used. As users are generally permitted to alter
3714 their &'gecos'& entries, no security considerations are involved. White space
3715 between &%-F%& and the <&'string'&> is optional.
3717 .vitem &%-f%&&~<&'address'&>
3718 .oindex "&%-f%&"
3719 .cindex "sender" "address"
3720 .cindex "address" "sender"
3721 .cindex "trusted users"
3722 .cindex "envelope sender"
3723 .cindex "user" "trusted"
3724 This option sets the address of the envelope sender of a locally-generated
3725 message (also known as the return path). The option can normally be used only
3726 by a trusted user, but &%untrusted_set_sender%& can be set to allow untrusted
3727 users to use it.
3729 Processes running as root or the Exim user are always trusted. Other
3730 trusted users are defined by the &%trusted_users%& or &%trusted_groups%&
3731 options. In the absence of &%-f%&, or if the caller is not trusted, the sender
3732 of a local message is set to the caller's login name at the default qualify
3733 domain.
3735 There is one exception to the restriction on the use of &%-f%&: an empty sender
3736 can be specified by any user, trusted or not, to create a message that can
3737 never provoke a bounce. An empty sender can be specified either as an empty
3738 string, or as a pair of angle brackets with nothing between them, as in these
3739 examples of shell commands:
3740 .code
3741 exim -f '<>' user@domain
3742 exim -f "" user@domain
3743 .endd
3744 In addition, the use of &%-f%& is not restricted when testing a filter file
3745 with &%-bf%& or when testing or verifying addresses using the &%-bt%& or
3746 &%-bv%& options.
3748 Allowing untrusted users to change the sender address does not of itself make
3749 it possible to send anonymous mail. Exim still checks that the &'From:'& header
3750 refers to the local user, and if it does not, it adds a &'Sender:'& header,
3751 though this can be overridden by setting &%no_local_from_check%&.
3753 White
3754 .cindex "&""From""& line"
3755 space between &%-f%& and the <&'address'&> is optional (that is, they can be
3756 given as two arguments or one combined argument). The sender of a
3757 locally-generated message can also be set (when permitted) by an initial
3758 &"From&~"& line in the message &-- see the description of &%-bm%& above &-- but
3759 if &%-f%& is also present, it overrides &"From&~"&.
3761 .vitem &%-G%&
3762 .oindex "&%-G%&"
3763 .cindex "submission fixups, suppressing (command-line)"
3764 This option is equivalent to an ACL applying:
3765 .code
3766 control = suppress_local_fixups
3767 .endd
3768 for every message received. Note that Sendmail will complain about such
3769 bad formatting, where Exim silently just does not fix it up. This may change
3770 in future.
3772 As this affects audit information, the caller must be a trusted user to use
3773 this option.
3775 .vitem &%-h%&&~<&'number'&>
3776 .oindex "&%-h%&"
3777 .cindex "Sendmail compatibility" "&%-h%& option ignored"
3778 This option is accepted for compatibility with Sendmail, but has no effect. (In
3779 Sendmail it overrides the &"hop count"& obtained by counting &'Received:'&
3780 headers.)
3782 .vitem &%-i%&
3783 .oindex "&%-i%&"
3784 .cindex "Solaris" "&'mail'& command"
3785 .cindex "dot" "in incoming non-SMTP message"
3786 This option, which has the same effect as &%-oi%&, specifies that a dot on a
3787 line by itself should not terminate an incoming, non-SMTP message. I can find
3788 no documentation for this option in Solaris 2.4 Sendmail, but the &'mailx'&
3789 command in Solaris 2.4 uses it. See also &%-ti%&.
3791 .vitem &%-L%&&~<&'tag'&>
3792 .oindex "&%-L%&"
3793 .cindex "syslog" "process name; set with flag"
3794 This option is equivalent to setting &%syslog_processname%& in the config
3795 file and setting &%log_file_path%& to &`syslog`&.
3796 Its use is restricted to administrators. The configuration file has to be
3797 read and parsed, to determine access rights, before this is set and takes
3798 effect, so early configuration file errors will not honour this flag.
3800 The tag should not be longer than 32 characters.
3802 .vitem &%-M%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3803 .oindex "&%-M%&"
3804 .cindex "forcing delivery"
3805 .cindex "delivery" "forcing attempt"
3806 .cindex "frozen messages" "forcing delivery"
3807 This option requests Exim to run a delivery attempt on each message in turn. If
3808 any of the messages are frozen, they are automatically thawed before the
3809 delivery attempt. The settings of &%queue_domains%&, &%queue_smtp_domains%&,
3810 and &%hold_domains%& are ignored.
3812 Retry
3813 .cindex "hints database" "overriding retry hints"
3814 hints for any of the addresses are overridden &-- Exim tries to deliver even if
3815 the normal retry time has not yet been reached. This option requires the caller
3816 to be an admin user. However, there is an option called &%prod_requires_admin%&
3817 which can be set false to relax this restriction (and also the same requirement
3818 for the &%-q%&, &%-R%&, and &%-S%& options).
3820 The deliveries happen synchronously, that is, the original Exim process does
3821 not terminate until all the delivery attempts have finished. No output is
3822 produced unless there is a serious error. If you want to see what is happening,
3823 use the &%-v%& option as well, or inspect Exim's main log.
3825 .vitem &%-Mar%&&~<&'message&~id'&>&~<&'address'&>&~<&'address'&>&~...
3826 .oindex "&%-Mar%&"
3827 .cindex "message" "adding recipients"
3828 .cindex "recipient" "adding"
3829 This option requests Exim to add the addresses to the list of recipients of the
3830 message (&"ar"& for &"add recipients"&). The first argument must be a message
3831 id, and the remaining ones must be email addresses. However, if the message is
3832 active (in the middle of a delivery attempt), it is not altered. This option
3833 can be used only by an admin user.
3835 .vitem "&%-MC%&&~<&'transport'&>&~<&'hostname'&>&~<&'sequence&~number'&>&&&
3836 &~<&'message&~id'&>"
3837 .oindex "&%-MC%&"
3838 .cindex "SMTP" "passed connection"
3839 .cindex "SMTP" "multiple deliveries"
3840 .cindex "multiple SMTP deliveries"
3841 This option is not intended for use by external callers. It is used internally
3842 by Exim to invoke another instance of itself to deliver a waiting message using
3843 an existing SMTP connection, which is passed as the standard input. Details are
3844 given in chapter &<<CHAPSMTP>>&. This must be the final option, and the caller
3845 must be root or the Exim user in order to use it.
3847 .vitem &%-MCA%&
3848 .oindex "&%-MCA%&"
3849 This option is not intended for use by external callers. It is used internally
3850 by Exim in conjunction with the &%-MC%& option. It signifies that the
3851 connection to the remote host has been authenticated.
3853 .vitem &%-MCD%&
3854 .oindex "&%-MCD%&"
3855 This option is not intended for use by external callers. It is used internally
3856 by Exim in conjunction with the &%-MC%& option. It signifies that the
3857 remote host supports the ESMTP &_DSN_& extension.
3859 .vitem &%-MCG%&&~<&'queue&~name'&>
3860 .oindex "&%-MCG%&"
3861 This option is not intended for use by external callers. It is used internally
3862 by Exim in conjunction with the &%-MC%& option. It signifies that an
3863 alternate queue is used, named by the following argument.
3865 .vitem &%-MCK%&
3866 .oindex "&%-MCK%&"
3867 This option is not intended for use by external callers. It is used internally
3868 by Exim in conjunction with the &%-MC%& option. It signifies that a
3869 remote host supports the ESMTP &_CHUNKING_& extension.
3871 .vitem &%-MCP%&
3872 .oindex "&%-MCP%&"
3873 This option is not intended for use by external callers. It is used internally
3874 by Exim in conjunction with the &%-MC%& option. It signifies that the server to
3875 which Exim is connected supports pipelining.
3877 .vitem &%-MCQ%&&~<&'process&~id'&>&~<&'pipe&~fd'&>
3878 .oindex "&%-MCQ%&"
3879 This option is not intended for use by external callers. It is used internally
3880 by Exim in conjunction with the &%-MC%& option when the original delivery was
3881 started by a queue runner. It passes on the process id of the queue runner,
3882 together with the file descriptor number of an open pipe. Closure of the pipe
3883 signals the final completion of the sequence of processes that are passing
3884 messages through the same SMTP connection.
3886 .vitem &%-MCS%&
3887 .oindex "&%-MCS%&"
3888 This option is not intended for use by external callers. It is used internally
3889 by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
3890 SMTP SIZE option should be used on messages delivered down the existing
3891 connection.
3893 .vitem &%-MCT%&
3894 .oindex "&%-MCT%&"
3895 This option is not intended for use by external callers. It is used internally
3896 by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
3897 host to which Exim is connected supports TLS encryption.
3899 .vitem &%-MCt%&&~<&'IP&~address'&>&~<&'port'&>&~<&'cipher'&>
3900 .oindex "&%-MCt%&"
3901 This option is not intended for use by external callers. It is used internally
3902 by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
3903 connection is being proxied by a parent process for handling TLS encryption.
3904 The arguments give the local address and port being proxied, and the TLS cipher.
3906 .vitem &%-Mc%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3907 .oindex "&%-Mc%&"
3908 .cindex "hints database" "not overridden by &%-Mc%&"
3909 .cindex "delivery" "manually started &-- not forced"
3910 This option requests Exim to run a delivery attempt on each message, in turn,
3911 but unlike the &%-M%& option, it does check for retry hints, and respects any
3912 that are found. This option is not very useful to external callers. It is
3913 provided mainly for internal use by Exim when it needs to re-invoke itself in
3914 order to regain root privilege for a delivery (see chapter &<<CHAPsecurity>>&).
3915 However, &%-Mc%& can be useful when testing, in order to run a delivery that
3916 respects retry times and other options such as &%hold_domains%& that are
3917 overridden when &%-M%& is used. Such a delivery does not count as a queue run.
3918 If you want to run a specific delivery as if in a queue run, you should use
3919 &%-q%& with a message id argument. A distinction between queue run deliveries
3920 and other deliveries is made in one or two places.
3922 .vitem &%-Mes%&&~<&'message&~id'&>&~<&'address'&>
3923 .oindex "&%-Mes%&"
3924 .cindex "message" "changing sender"
3925 .cindex "sender" "changing"
3926 This option requests Exim to change the sender address in the message to the
3927 given address, which must be a fully qualified address or &"<>"& (&"es"& for
3928 &"edit sender"&). There must be exactly two arguments. The first argument must
3929 be a message id, and the second one an email address. However, if the message
3930 is active (in the middle of a delivery attempt), its status is not altered.
3931 This option can be used only by an admin user.
3933 .vitem &%-Mf%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3934 .oindex "&%-Mf%&"
3935 .cindex "freezing messages"
3936 .cindex "message" "manually freezing"
3937 This option requests Exim to mark each listed message as &"frozen"&. This
3938 prevents any delivery attempts taking place until the message is &"thawed"&,
3939 either manually or as a result of the &%auto_thaw%& configuration option.
3940 However, if any of the messages are active (in the middle of a delivery
3941 attempt), their status is not altered. This option can be used only by an admin
3942 user.
3944 .vitem &%-Mg%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3945 .oindex "&%-Mg%&"
3946 .cindex "giving up on messages"
3947 .cindex "message" "abandoning delivery attempts"
3948 .cindex "delivery" "abandoning further attempts"
3949 This option requests Exim to give up trying to deliver the listed messages,
3950 including any that are frozen. However, if any of the messages are active,
3951 their status is not altered. For non-bounce messages, a delivery error message
3952 is sent to the sender, containing the text &"cancelled by administrator"&.
3953 Bounce messages are just discarded. This option can be used only by an admin
3954 user.
3956 .vitem &%-Mmad%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3957 .oindex "&%-Mmad%&"
3958 .cindex "delivery" "cancelling all"
3959 This option requests Exim to mark all the recipient addresses in the messages
3960 as already delivered (&"mad"& for &"mark all delivered"&). However, if any
3961 message is active (in the middle of a delivery attempt), its status is not
3962 altered. This option can be used only by an admin user.
3964 .vitem &%-Mmd%&&~<&'message&~id'&>&~<&'address'&>&~<&'address'&>&~...
3965 .oindex "&%-Mmd%&"
3966 .cindex "delivery" "cancelling by address"
3967 .cindex "recipient" "removing"
3968 .cindex "removing recipients"
3969 This option requests Exim to mark the given addresses as already delivered
3970 (&"md"& for &"mark delivered"&). The first argument must be a message id, and
3971 the remaining ones must be email addresses. These are matched to recipient
3972 addresses in the message in a case-sensitive manner. If the message is active
3973 (in the middle of a delivery attempt), its status is not altered. This option
3974 can be used only by an admin user.
3976 .vitem &%-Mrm%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3977 .oindex "&%-Mrm%&"
3978 .cindex "removing messages"
3979 .cindex "abandoning mail"
3980 .cindex "message" "manually discarding"
3981 This option requests Exim to remove the given messages from the queue. No
3982 bounce messages are sent; each message is simply forgotten. However, if any of
3983 the messages are active, their status is not altered. This option can be used
3984 only by an admin user or by the user who originally caused the message to be
3985 placed in the queue.
3987 . .new
3988 . .vitem &%-MS%&
3989 . .oindex "&%-MS%&"
3990 . .cindex REQUIRETLS
3991 . This option is used to request REQUIRETLS processing on the message.
3992 . It is used internally by Exim in conjunction with -E when generating
3993 . a bounce message.
3994 . .wen
3996 .vitem &%-Mset%&&~<&'message&~id'&>
3997 .oindex "&%-Mset%&"
3998 .cindex "testing" "string expansion"
3999 .cindex "expansion" "testing"
4000 This option is useful only in conjunction with &%-be%& (that is, when testing
4001 string expansions). Exim loads the given message from its spool before doing
4002 the test expansions, thus setting message-specific variables such as
4003 &$message_size$& and the header variables. The &$recipients$& variable is made
4004 available. This feature is provided to make it easier to test expansions that
4005 make use of these variables. However, this option can be used only by an admin
4006 user. See also &%-bem%&.
4008 .vitem &%-Mt%&&~<&'message&~id'&>&~<&'message&~id'&>&~...