[exim.git] / doc / doc-docbook / spec.xfpt
1 . $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.88 2010/06/14 18:51:09 pdp Exp $
2 .
3 . /////////////////////////////////////////////////////////////////////////////
4 . This is the primary source of the Exim Manual. It is an xfpt document that is
5 . converted into DocBook XML for subsequent conversion into printing and online
6 . formats. The markup used herein is "standard" xfpt markup, with some extras.
7 . The markup is summarized in a file called Markup.txt.
8 .
9 . WARNING: When you use the .new macro, make sure it appears *before* any
10 . adjacent index items; otherwise you get an empty "paragraph" which causes
11 . unwanted vertical space.
12 . /////////////////////////////////////////////////////////////////////////////
14 .include stdflags
15 .include stdmacs
17 . /////////////////////////////////////////////////////////////////////////////
18 . This outputs the standard DocBook boilerplate.
19 . /////////////////////////////////////////////////////////////////////////////
21 .docbook
23 . /////////////////////////////////////////////////////////////////////////////
24 . These lines are processing instructions for the Simple DocBook Processor that
25 . Philip Hazel has developed as a less cumbersome way of making PostScript and
26 . PDFs than using xmlto and fop. They will be ignored by all other XML
27 . processors.
28 . /////////////////////////////////////////////////////////////////////////////
30 .literal xml
31 <?sdop
32 foot_right_recto="&chaptertitle; (&chapternumber;)"
33 foot_right_verso="&chaptertitle; (&chapternumber;)"
34 toc_chapter_blanks="yes,yes"
35 table_warn_overflow="overprint"
36 ?>
37 .literal off
39 . /////////////////////////////////////////////////////////////////////////////
40 . This generate the outermost <book> element that wraps then entire document.
41 . /////////////////////////////////////////////////////////////////////////////
43 .book
45 . /////////////////////////////////////////////////////////////////////////////
46 . These definitions set some parameters and save some typing. Remember that
47 . the <bookinfo> element must also be updated for each new edition.
48 . /////////////////////////////////////////////////////////////////////////////
50 .set previousversion "4.72"
51 .set version "4.73"
53 .set ACL "access control lists (ACLs)"
54 .set I "&nbsp;&nbsp;&nbsp;&nbsp;"
57 . /////////////////////////////////////////////////////////////////////////////
58 . Additional xfpt markup used by this document, over and above the default
59 . provided in the xfpt library.
60 . /////////////////////////////////////////////////////////////////////////////
62 . --- Override the &$ flag to automatically insert a $ with the variable name
64 .flag &$ $& "<varname>$" "</varname>"
66 . --- Short flags for daggers in option headings. They will always be inside
67 . --- an italic string, but we want the daggers to be roman.
69 .flag &!! "</emphasis>&dagger;<emphasis>"
70 .flag &!? "</emphasis>&Dagger;<emphasis>"
72 . --- A macro for an Exim option definition heading, generating a one-line
73 . --- table with four columns. For cases when the option name is given with
74 . --- a space, so that it can be split, a fifth argument is used for the
75 . --- index entry.
77 .macro option
78 .arg 5
79 .oindex "&%$5%&"
80 .endarg
81 .arg -5
82 .oindex "&%$1%&"
83 .endarg
84 .itable all 0 0 4 8* left 6* center 6* center 6* right
85 .row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&"
86 .endtable
87 .endmacro
89 . --- A macro for the common 2-column tables. The width of the first column
90 . --- is suitable for the many tables at the start of the main options chapter;
91 . --- the small number of other 2-column tables override it.
93 .macro table2 196pt 254pt
94 .itable none 0 0 2 $1 left $2 left
95 .endmacro
97 . --- A macro that generates .row, but puts &I; at the start of the first
98 . --- argument, thus indenting it. Assume a minimum of two arguments, and
99 . --- allow up to four arguments, which is as many as we'll ever need.
101 .macro irow
102 .arg 4
103 .row "&I;$1" "$2" "$3" "$4"
104 .endarg
105 .arg -4
106 .arg 3
107 .row "&I;$1" "$2" "$3"
108 .endarg
109 .arg -3
110 .row "&I;$1" "$2"
111 .endarg
112 .endarg
113 .endmacro
115 . --- Macros for option, variable, and concept index entries. For a "range"
116 . --- style of entry, use .scindex for the start and .ecindex for the end. The
117 . --- first argument of .scindex and the only argument of .ecindex must be the
118 . --- ID that ties them together.
120 .macro cindex
121 &<indexterm role="concept">&
122 &<primary>&$1&</primary>&
123 .arg 2
124 &<secondary>&$2&</secondary>&
125 .endarg
126 &</indexterm>&
127 .endmacro
129 .macro scindex
130 &<indexterm role="concept" id="$1" class="startofrange">&
131 &<primary>&$2&</primary>&
132 .arg 3
133 &<secondary>&$3&</secondary>&
134 .endarg
135 &</indexterm>&
136 .endmacro
138 .macro ecindex
139 &<indexterm role="concept" startref="$1" class="endofrange"/>&
140 .endmacro
142 .macro oindex
143 &<indexterm role="option">&
144 &<primary>&$1&</primary>&
145 .arg 2
146 &<secondary>&$2&</secondary>&
147 .endarg
148 &</indexterm>&
149 .endmacro
151 .macro vindex
152 &<indexterm role="variable">&
153 &<primary>&$1&</primary>&
154 .arg 2
155 &<secondary>&$2&</secondary>&
156 .endarg
157 &</indexterm>&
158 .endmacro
160 .macro index
161 .echo "** Don't use .index; use .cindex or .oindex or .vindex"
162 .endmacro
163 . ////////////////////////////////////////////////////////////////////////////
166 . ////////////////////////////////////////////////////////////////////////////
167 . The <bookinfo> element is removed from the XML before processing for Ascii
168 . output formats.
169 . ////////////////////////////////////////////////////////////////////////////
171 .literal xml
172 <bookinfo>
173 <title>Specification of the Exim Mail Transfer Agent</title>
174 <titleabbrev>The Exim MTA</titleabbrev>
175 <date>29 May 2010</date>
176 <author><firstname>Exim</firstname><surname>Maintainers</surname></author>
177 <authorinitials>EM</authorinitials>
178 <revhistory><revision>
179 <revnumber>4.73</revnumber>
180 <date>19 Nov 2010</date>
181 <authorinitials>EM</authorinitials>
182 </revision></revhistory>
183 <copyright><year>2009</year><holder>University of Cambridge</holder></copyright>
184 </bookinfo>
185 .literal off
188 . /////////////////////////////////////////////////////////////////////////////
189 . This chunk of literal XML implements index entries of the form "x, see y" and
190 . "x, see also y". However, the DocBook DTD doesn't allow <indexterm> entries
191 . at the top level, so we have to put the .chapter directive first.
192 . /////////////////////////////////////////////////////////////////////////////
194 .chapter "Introduction" "CHID1"
195 .literal xml
197 <indexterm role="variable">
198 <primary>$1, $2, etc.</primary>
199 <see><emphasis>numerical variables</emphasis></see>
200 </indexterm>
201 <indexterm role="concept">
202 <primary>address</primary>
203 <secondary>rewriting</secondary>
204 <see><emphasis>rewriting</emphasis></see>
205 </indexterm>
206 <indexterm role="concept">
207 <primary>Bounce Address Tag Validation</primary>
208 <see><emphasis>BATV</emphasis></see>
209 </indexterm>
210 <indexterm role="concept">
211 <primary>Client SMTP Authorization</primary>
212 <see><emphasis>CSA</emphasis></see>
213 </indexterm>
214 <indexterm role="concept">
215 <primary>CR character</primary>
216 <see><emphasis>carriage return</emphasis></see>
217 </indexterm>
218 <indexterm role="concept">
219 <primary>CRL</primary>
220 <see><emphasis>certificate revocation list</emphasis></see>
221 </indexterm>
222 <indexterm role="concept">
223 <primary>delivery</primary>
224 <secondary>failure report</secondary>
225 <see><emphasis>bounce message</emphasis></see>
226 </indexterm>
227 <indexterm role="concept">
228 <primary>dialup</primary>
229 <see><emphasis>intermittently connected hosts</emphasis></see>
230 </indexterm>
231 <indexterm role="concept">
232 <primary>exiscan</primary>
233 <see><emphasis>content scanning</emphasis></see>
234 </indexterm>
235 <indexterm role="concept">
236 <primary>failover</primary>
237 <see><emphasis>fallback</emphasis></see>
238 </indexterm>
239 <indexterm role="concept">
240 <primary>fallover</primary>
241 <see><emphasis>fallback</emphasis></see>
242 </indexterm>
243 <indexterm role="concept">
244 <primary>filter</primary>
245 <secondary>Sieve</secondary>
246 <see><emphasis>Sieve filter</emphasis></see>
247 </indexterm>
248 <indexterm role="concept">
249 <primary>ident</primary>
250 <see><emphasis>RFC 1413</emphasis></see>
251 </indexterm>
252 <indexterm role="concept">
253 <primary>LF character</primary>
254 <see><emphasis>linefeed</emphasis></see>
255 </indexterm>
256 <indexterm role="concept">
257 <primary>maximum</primary>
258 <seealso><emphasis>limit</emphasis></seealso>
259 </indexterm>
260 <indexterm role="concept">
261 <primary>monitor</primary>
262 <see><emphasis>Exim monitor</emphasis></see>
263 </indexterm>
264 <indexterm role="concept">
265 <primary>no_<emphasis>xxx</emphasis></primary>
266 <see>entry for xxx</see>
267 </indexterm>
268 <indexterm role="concept">
269 <primary>NUL</primary>
270 <see><emphasis>binary zero</emphasis></see>
271 </indexterm>
272 <indexterm role="concept">
273 <primary>passwd file</primary>
274 <see><emphasis>/etc/passwd</emphasis></see>
275 </indexterm>
276 <indexterm role="concept">
277 <primary>process id</primary>
278 <see><emphasis>pid</emphasis></see>
279 </indexterm>
280 <indexterm role="concept">
281 <primary>RBL</primary>
282 <see><emphasis>DNS list</emphasis></see>
283 </indexterm>
284 <indexterm role="concept">
285 <primary>redirection</primary>
286 <see><emphasis>address redirection</emphasis></see>
287 </indexterm>
288 <indexterm role="concept">
289 <primary>return path</primary>
290 <seealso><emphasis>envelope sender</emphasis></seealso>
291 </indexterm>
292 <indexterm role="concept">
293 <primary>scanning</primary>
294 <see><emphasis>content scanning</emphasis></see>
295 </indexterm>
296 <indexterm role="concept">
297 <primary>SSL</primary>
298 <see><emphasis>TLS</emphasis></see>
299 </indexterm>
300 <indexterm role="concept">
301 <primary>string</primary>
302 <secondary>expansion</secondary>
303 <see><emphasis>expansion</emphasis></see>
304 </indexterm>
305 <indexterm role="concept">
306 <primary>top bit</primary>
307 <see><emphasis>8-bit characters</emphasis></see>
308 </indexterm>
309 <indexterm role="concept">
310 <primary>variables</primary>
311 <see><emphasis>expansion, variables</emphasis></see>
312 </indexterm>
313 <indexterm role="concept">
314 <primary>zero, binary</primary>
315 <see><emphasis>binary zero</emphasis></see>
316 </indexterm>
318 .literal off
321 . /////////////////////////////////////////////////////////////////////////////
322 . This is the real start of the first chapter. See the comment above as to why
323 . we can't have the .chapter line here.
324 . chapter "Introduction"
325 . /////////////////////////////////////////////////////////////////////////////
327 Exim is a mail transfer agent (MTA) for hosts that are running Unix or
328 Unix-like operating systems. It was designed on the assumption that it would be
329 run on hosts that are permanently connected to the Internet. However, it can be
330 used on intermittently connected hosts with suitable configuration adjustments.
332 Configuration files currently exist for the following operating systems: AIX,
333 BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, Dragonfly, FreeBSD, GNU/Hurd,
334 GNU/Linux, HI-OSF (Hitachi), HI-UX, HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD,
335 OpenUNIX, QNX, SCO, SCO SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4,
336 Tru64-Unix (formerly Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware.
337 Some of these operating systems are no longer current and cannot easily be
338 tested, so the configuration files may no longer work in practice.
340 There are also configuration files for compiling Exim in the Cygwin environment
341 that can be installed on systems running Windows. However, this document does
342 not contain any information about running Exim in the Cygwin environment.
344 The terms and conditions for the use and distribution of Exim are contained in
345 the file &_NOTICE_&. Exim is distributed under the terms of the GNU General
346 Public Licence, a copy of which may be found in the file &_LICENCE_&.
348 The use, supply or promotion of Exim for the purpose of sending bulk,
349 unsolicited electronic mail is incompatible with the basic aims of the program,
350 which revolve around the free provision of a service that enhances the quality
351 of personal communications. The author of Exim regards indiscriminate
352 mass-mailing as an antisocial, irresponsible abuse of the Internet.
354 Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
355 experience of running and working on the Smail 3 code, I could never have
356 contemplated starting to write a new MTA. Many of the ideas and user interfaces
357 were originally taken from Smail 3, though the actual code of Exim is entirely
358 new, and has developed far beyond the initial concept.
360 Many people, both in Cambridge and around the world, have contributed to the
361 development and the testing of Exim, and to porting it to various operating
362 systems. I am grateful to them all. The distribution now contains a file called
363 &_ACKNOWLEDGMENTS_&, in which I have started recording the names of
364 contributors.
367 .section "Exim documentation" "SECID1"
368 . Keep this example change bar when updating the documentation!
369 .new
370 .cindex "documentation"
371 This edition of the Exim specification applies to version &version; of Exim.
372 Substantive changes from the &previousversion; edition are marked in some
373 renditions of the document; this paragraph is so marked if the rendition is
374 capable of showing a change indicator.
375 .wen
377 This document is very much a reference manual; it is not a tutorial. The reader
378 is expected to have some familiarity with the SMTP mail transfer protocol and
379 with general Unix system administration. Although there are some discussions
380 and examples in places, the information is mostly organized in a way that makes
381 it easy to look up, rather than in a natural order for sequential reading.
382 Furthermore, the manual aims to cover every aspect of Exim in detail, including
383 a number of rarely-used, special-purpose features that are unlikely to be of
384 very wide interest.
386 .cindex "books about Exim"
387 An &"easier"& discussion of Exim which provides more in-depth explanatory,
388 introductory, and tutorial material can be found in a book entitled &'The Exim
389 SMTP Mail Server'& (second edition, 2007), published by UIT Cambridge
390 (&url(http://www.uit.co.uk/exim-book/)).
392 This book also contains a chapter that gives a general introduction to SMTP and
393 Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
394 with the latest release of Exim. (Note that the earlier book about Exim,
395 published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
397 .cindex "Debian" "information sources"
398 If you are using a Debian distribution of Exim, you will find information about
399 Debian-specific features in the file
400 &_/usr/share/doc/exim4-base/README.Debian_&.
401 The command &(man update-exim.conf)& is another source of Debian-specific
402 information.
404 .cindex "&_doc/NewStuff_&"
405 .cindex "&_doc/ChangeLog_&"
406 .cindex "change log"
407 As the program develops, there may be features in newer versions that have not
408 yet made it into this document, which is updated only when the most significant
409 digit of the fractional part of the version number changes. Specifications of
410 new features that are not yet in this manual are placed in the file
411 &_doc/NewStuff_& in the Exim distribution.
413 Some features may be classified as &"experimental"&. These may change
414 incompatibly while they are developing, or even be withdrawn. For this reason,
415 they are not documented in this manual. Information about experimental features
416 can be found in the file &_doc/experimental.txt_&.
418 All changes to the program (whether new features, bug fixes, or other kinds of
419 change) are noted briefly in the file called &_doc/ChangeLog_&.
421 .cindex "&_doc/spec.txt_&"
422 This specification itself is available as an ASCII file in &_doc/spec.txt_& so
423 that it can easily be searched with a text editor. Other files in the &_doc_&
424 directory are:
426 .table2 100pt
427 .row &_OptionLists.txt_& "list of all options in alphabetical order"
428 .row &_dbm.discuss.txt_& "discussion about DBM libraries"
429 .row &_exim.8_& "a man page of Exim's command line options"
430 .row &_experimental.txt_& "documentation of experimental features"
431 .row &_filter.txt_& "specification of the filter language"
432 .row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
433 .row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
434 .endtable
436 The main specification and the specification of the filtering language are also
437 available in other formats (HTML, PostScript, PDF, and Texinfo). Section
438 &<<SECTavail>>& below tells you how to get hold of these.
442 .section "FTP and web sites" "SECID2"
443 .cindex "web site"
444 .cindex "FTP site"
445 The primary site for Exim source distributions is currently the University of
446 Cambridge's FTP site, whose contents are described in &'Where to find the Exim
447 distribution'& below. In addition, there is a web site and an FTP site at
448 &%exim.org%&. These are now also hosted at the University of Cambridge. The
449 &%exim.org%& site was previously hosted for a number of years by Energis
450 Squared, formerly Planet Online Ltd, whose support I gratefully acknowledge.
452 .cindex "wiki"
453 .cindex "FAQ"
454 As well as Exim distribution tar files, the Exim web site contains a number of
455 differently formatted versions of the documentation. A recent addition to the
456 online information is the Exim wiki (&url(http://wiki.exim.org)),
457 which contains what used to be a separate FAQ, as well as various other
458 examples, tips, and know-how that have been contributed by Exim users.
460 .cindex Bugzilla
461 An Exim Bugzilla exists at &url(http://bugs.exim.org). You can use
462 this to report bugs, and also to add items to the wish list. Please search
463 first to check that you are not duplicating a previous entry.
467 .section "Mailing lists" "SECID3"
468 .cindex "mailing lists" "for Exim users"
469 The following Exim mailing lists exist:
471 .table2 140pt
472 .row &'exim-users@exim.org'& "General discussion list"
473 .row &'exim-dev@exim.org'& "Discussion of bugs, enhancements, etc."
474 .row &'exim-announce@exim.org'& "Moderated, low volume announcements list"
475 .row &'exim-future@exim.org'& "Discussion of long-term development"
476 .endtable
478 You can subscribe to these lists, change your existing subscriptions, and view
479 or search the archives via the mailing lists link on the Exim home page.
480 .cindex "Debian" "mailing list for"
481 If you are using a Debian distribution of Exim, you may wish to subscribe to
482 the Debian-specific mailing list &'pkg-exim4-users@lists.alioth.debian.org'&
483 via this web page:
484 .display
485 &url(http://lists.alioth.debian.org/mailman/listinfo/pkg-exim4-users)
486 .endd
487 Please ask Debian-specific questions on this list and not on the general Exim
488 lists.
490 .section "Exim training" "SECID4"
491 .cindex "training courses"
492 Training courses in Cambridge (UK) used to be run annually by the author of
493 Exim, before he retired. At the time of writing, there are no plans to run
494 further Exim courses in Cambridge. However, if that changes, relevant
495 information will be posted at &url(http://www-tus.csx.cam.ac.uk/courses/exim/).
497 .section "Bug reports" "SECID5"
498 .cindex "bug reports"
499 .cindex "reporting bugs"
500 Reports of obvious bugs can be emailed to &'bugs@exim.org'& or reported
501 via the Bugzilla (&url(http://bugs.exim.org)). However, if you are unsure
502 whether some behaviour is a bug or not, the best thing to do is to post a
503 message to the &'exim-dev'& mailing list and have it discussed.
507 .section "Where to find the Exim distribution" "SECTavail"
508 .cindex "FTP site"
509 .cindex "distribution" "ftp site"
510 The master ftp site for the Exim distribution is
511 .display
512 &*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim*&
513 .endd
514 This is mirrored by
515 .display
516 &*ftp://ftp.exim.org/pub/exim*&
517 .endd
518 The file references that follow are relative to the &_exim_& directories at
519 these sites. There are now quite a number of independent mirror sites around
520 the world. Those that I know about are listed in the file called &_Mirrors_&.
522 Within the &_exim_& directory there are subdirectories called &_exim3_& (for
523 previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
524 distributions), and &_Testing_& for testing versions. In the &_exim4_&
525 subdirectory, the current release can always be found in files called
526 .display
527 &_exim-n.nn.tar.gz_&
528 &_exim-n.nn.tar.bz2_&
529 .endd
530 where &'n.nn'& is the highest such version number in the directory. The two
531 files contain identical data; the only difference is the type of compression.
532 The &_.bz2_& file is usually a lot smaller than the &_.gz_& file.
534 .cindex "distribution" "signing details"
535 .cindex "distribution" "public key"
536 .cindex "public key for signed distribution"
537 The distributions are currently signed with Nigel Metheringham's GPG key. The
538 corresponding public key is available from a number of keyservers, and there is
539 also a copy in the file &_nigel-pubkey.asc_&. The signatures for the tar bundles are
540 in:
541 .display
542 &_exim-n.nn.tar.gz.asc_&
543 &_exim-n.nn.tar.bz2.asc_&
544 .endd
545 For each released version, the log of changes is made separately available in a
546 separate file in the directory &_ChangeLogs_& so that it is possible to
547 find out what has changed without having to download the entire distribution.
549 .cindex "documentation" "available formats"
550 The main distribution contains ASCII versions of this specification and other
551 documentation; other formats of the documents are available in separate files
552 inside the &_exim4_& directory of the FTP site:
553 .display
554 &_exim-html-n.nn.tar.gz_&
555 &_exim-pdf-n.nn.tar.gz_&
556 &_exim-postscript-n.nn.tar.gz_&
557 &_exim-texinfo-n.nn.tar.gz_&
558 .endd
559 These tar files contain only the &_doc_& directory, not the complete
560 distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
563 .section "Limitations" "SECID6"
564 .ilist
565 .cindex "limitations of Exim"
566 .cindex "bang paths" "not handled by Exim"
567 Exim is designed for use as an Internet MTA, and therefore handles addresses in
568 RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
569 simple two-component bang paths can be converted by a straightforward rewriting
570 configuration. This restriction does not prevent Exim from being interfaced to
571 UUCP as a transport mechanism, provided that domain addresses are used.
572 .next
573 .cindex "domainless addresses"
574 .cindex "address" "without domain"
575 Exim insists that every address it handles has a domain attached. For incoming
576 local messages, domainless addresses are automatically qualified with a
577 configured domain value. Configuration options specify from which remote
578 systems unqualified addresses are acceptable. These are then qualified on
579 arrival.
580 .next
581 .cindex "transport" "external"
582 .cindex "external transports"
583 The only external transport mechanisms that are currently implemented are SMTP
584 and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
585 transport is available, and there are facilities for writing messages to files
586 and pipes, optionally in &'batched SMTP'& format; these facilities can be used
587 to send messages to other transport mechanisms such as UUCP, provided they can
588 handle domain-style addresses. Batched SMTP input is also catered for.
589 .next
590 Exim is not designed for storing mail for dial-in hosts. When the volumes of
591 such mail are large, it is better to get the messages &"delivered"& into files
592 (that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
593 other means.
594 .next
595 Although Exim does have basic facilities for scanning incoming messages, these
596 are not comprehensive enough to do full virus or spam scanning. Such operations
597 are best carried out using additional specialized software packages. If you
598 compile Exim with the content-scanning extension, straightforward interfaces to
599 a number of common scanners are provided.
600 .endlist
603 .section "Run time configuration" "SECID7"
604 Exim's run time configuration is held in a single text file that is divided
605 into a number of sections. The entries in this file consist of keywords and
606 values, in the style of Smail 3 configuration files. A default configuration
607 file which is suitable for simple online installations is provided in the
608 distribution, and is described in chapter &<<CHAPdefconfil>>& below.
611 .section "Calling interface" "SECID8"
612 .cindex "Sendmail compatibility" "command line interface"
613 Like many MTAs, Exim has adopted the Sendmail command line interface so that it
614 can be a straight replacement for &_/usr/lib/sendmail_& or
615 &_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
616 about Sendmail in order to run Exim. For actions other than sending messages,
617 Sendmail-compatible options also exist, but those that produce output (for
618 example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
619 format. There are also some additional options that are compatible with Smail
620 3, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
621 documents all Exim's command line options. This information is automatically
622 made into the man page that forms part of the Exim distribution.
624 Control of messages on the queue can be done via certain privileged command
625 line options. There is also an optional monitor program called &'eximon'&,
626 which displays current information in an X window, and which contains a menu
627 interface to Exim's command line administration options.
631 .section "Terminology" "SECID9"
632 .cindex "terminology definitions"
633 .cindex "body of message" "definition of"
634 The &'body'& of a message is the actual data that the sender wants to transmit.
635 It is the last part of a message, and is separated from the &'header'& (see
636 below) by a blank line.
638 .cindex "bounce message" "definition of"
639 When a message cannot be delivered, it is normally returned to the sender in a
640 delivery failure message or a &"non-delivery report"& (NDR). The term
641 &'bounce'& is commonly used for this action, and the error reports are often
642 called &'bounce messages'&. This is a convenient shorthand for &"delivery
643 failure error report"&. Such messages have an empty sender address in the
644 message's &'envelope'& (see below) to ensure that they cannot themselves give
645 rise to further bounce messages.
647 The term &'default'& appears frequently in this manual. It is used to qualify a
648 value which is used in the absence of any setting in the configuration. It may
649 also qualify an action which is taken unless a configuration setting specifies
650 otherwise.
652 The term &'defer'& is used when the delivery of a message to a specific
653 destination cannot immediately take place for some reason (a remote host may be
654 down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
655 until a later time.
657 The word &'domain'& is sometimes used to mean all but the first component of a
658 host's name. It is &'not'& used in that sense here, where it normally refers to
659 the part of an email address following the @ sign.
661 .cindex "envelope, definition of"
662 .cindex "sender" "definition of"
663 A message in transit has an associated &'envelope'&, as well as a header and a
664 body. The envelope contains a sender address (to which bounce messages should
665 be delivered), and any number of recipient addresses. References to the
666 sender or the recipients of a message usually mean the addresses in the
667 envelope. An MTA uses these addresses for delivery, and for returning bounce
668 messages, not the addresses that appear in the header lines.
670 .cindex "message" "header, definition of"
671 .cindex "header section" "definition of"
672 The &'header'& of a message is the first part of a message's text, consisting
673 of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
674 &'Subject:'&, etc. Long header lines can be split over several text lines by
675 indenting the continuations. The header is separated from the body by a blank
676 line.
678 .cindex "local part" "definition of"
679 .cindex "domain" "definition of"
680 The term &'local part'&, which is taken from RFC 2822, is used to refer to that
681 part of an email address that precedes the @ sign. The part that follows the
682 @ sign is called the &'domain'& or &'mail domain'&.
684 .cindex "local delivery" "definition of"
685 .cindex "remote delivery, definition of"
686 The terms &'local delivery'& and &'remote delivery'& are used to distinguish
687 delivery to a file or a pipe on the local host from delivery by SMTP over
688 TCP/IP to another host. As far as Exim is concerned, all hosts other than the
689 host it is running on are &'remote'&.
691 .cindex "return path" "definition of"
692 &'Return path'& is another name that is used for the sender address in a
693 message's envelope.
695 .cindex "queue" "definition of"
696 The term &'queue'& is used to refer to the set of messages awaiting delivery,
697 because this term is in widespread use in the context of MTAs. However, in
698 Exim's case the reality is more like a pool than a queue, because there is
699 normally no ordering of waiting messages.
701 .cindex "queue runner" "definition of"
702 The term &'queue runner'& is used to describe a process that scans the queue
703 and attempts to deliver those messages whose retry times have come. This term
704 is used by other MTAs, and also relates to the command &%runq%&, but in Exim
705 the waiting messages are normally processed in an unpredictable order.
707 .cindex "spool directory" "definition of"
708 The term &'spool directory'& is used for a directory in which Exim keeps the
709 messages on its queue &-- that is, those that it is in the process of
710 delivering. This should not be confused with the directory in which local
711 mailboxes are stored, which is called a &"spool directory"& by some people. In
712 the Exim documentation, &"spool"& is always used in the first sense.
719 . ////////////////////////////////////////////////////////////////////////////
720 . ////////////////////////////////////////////////////////////////////////////
722 .chapter "Incorporated code" "CHID2"
723 .cindex "incorporated code"
724 .cindex "regular expressions" "library"
725 .cindex "PCRE"
726 A number of pieces of external code are included in the Exim distribution.
728 .ilist
729 Regular expressions are supported in the main Exim program and in the
730 Exim monitor using the freely-distributable PCRE library, copyright
731 &copy; University of Cambridge. The source to PCRE is no longer shipped with
732 Exim, so you will need to use the version of PCRE shipped with your system,
733 or obtain and install the full version of the library from
734 &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
735 .next
736 .cindex "cdb" "acknowledgment"
737 Support for the cdb (Constant DataBase) lookup method is provided by code
738 contributed by Nigel Metheringham of (at the time he contributed it) Planet
739 Online Ltd. The implementation is completely contained within the code of Exim.
740 It does not link against an external cdb library. The code contains the
741 following statements:
743 .blockquote
744 Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
746 This program is free software; you can redistribute it and/or modify it under
747 the terms of the GNU General Public License as published by the Free Software
748 Foundation; either version 2 of the License, or (at your option) any later
749 version.
750 This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
751 the spec and sample code for cdb can be obtained from
752 &url(http://www.pobox.com/~djb/cdb.html). This implementation borrows
753 some code from Dan Bernstein's implementation (which has no license
754 restrictions applied to it).
755 .endblockquote
756 .next
757 .cindex "SPA authentication"
758 .cindex "Samba project"
759 .cindex "Microsoft Secure Password Authentication"
760 Client support for Microsoft's &'Secure Password Authentication'& is provided
761 by code contributed by Marc Prud'hommeaux. Server support was contributed by
762 Tom Kistner. This includes code taken from the Samba project, which is released
763 under the Gnu GPL.
764 .next
765 .cindex "Cyrus"
766 .cindex "&'pwcheck'& daemon"
767 .cindex "&'pwauthd'& daemon"
768 Support for calling the Cyrus &'pwcheck'& and &'saslauthd'& daemons is provided
769 by code taken from the Cyrus-SASL library and adapted by Alexander S.
770 Sabourenkov. The permission notice appears below, in accordance with the
771 conditions expressed therein.
773 .blockquote
774 Copyright &copy; 2001 Carnegie Mellon University. All rights reserved.
776 Redistribution and use in source and binary forms, with or without
777 modification, are permitted provided that the following conditions
778 are met:
780 .olist
781 Redistributions of source code must retain the above copyright
782 notice, this list of conditions and the following disclaimer.
783 .next
784 Redistributions in binary form must reproduce the above copyright
785 notice, this list of conditions and the following disclaimer in
786 the documentation and/or other materials provided with the
787 distribution.
788 .next
789 The name &"Carnegie Mellon University"& must not be used to
790 endorse or promote products derived from this software without
791 prior written permission. For permission or any other legal
792 details, please contact
793 .display
794 Office of Technology Transfer
795 Carnegie Mellon University
796 5000 Forbes Avenue
797 Pittsburgh, PA 15213-3890
798 (412) 268-4387, fax: (412) 268-7395
799 tech-transfer@andrew.cmu.edu
800 .endd
801 .next
802 Redistributions of any form whatsoever must retain the following
803 acknowledgment:
805 &"This product includes software developed by Computing Services
806 at Carnegie Mellon University (&url(http://www.cmu.edu/computing/)."&
815 .endlist
816 .endblockquote
818 .next
819 .cindex "Exim monitor" "acknowledgment"
820 .cindex "X-windows"
821 .cindex "Athena"
822 The Exim Monitor program, which is an X-Window application, includes
823 modified versions of the Athena StripChart and TextPop widgets.
824 This code is copyright by DEC and MIT, and their permission notice appears
825 below, in accordance with the conditions expressed therein.
827 .blockquote
828 Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
829 and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
831 All Rights Reserved
833 Permission to use, copy, modify, and distribute this software and its
834 documentation for any purpose and without fee is hereby granted,
835 provided that the above copyright notice appear in all copies and that
836 both that copyright notice and this permission notice appear in
837 supporting documentation, and that the names of Digital or MIT not be
838 used in advertising or publicity pertaining to distribution of the
839 software without specific, written prior permission.
848 .endblockquote
850 .next
851 Many people have contributed code fragments, some large, some small, that were
852 not covered by any specific licence requirements. It is assumed that the
853 contributors are happy to see their code incorporated into Exim under the GPL.
854 .endlist
860 . ////////////////////////////////////////////////////////////////////////////
861 . ////////////////////////////////////////////////////////////////////////////
863 .chapter "How Exim receives and delivers mail" "CHID11" &&&
864 "Receiving and delivering mail"
867 .section "Overall philosophy" "SECID10"
868 .cindex "design philosophy"
869 Exim is designed to work efficiently on systems that are permanently connected
870 to the Internet and are handling a general mix of mail. In such circumstances,
871 most messages can be delivered immediately. Consequently, Exim does not
872 maintain independent queues of messages for specific domains or hosts, though
873 it does try to send several messages in a single SMTP connection after a host
874 has been down, and it also maintains per-host retry information.
877 .section "Policy control" "SECID11"
878 .cindex "policy control" "overview"
879 Policy controls are now an important feature of MTAs that are connected to the
880 Internet. Perhaps their most important job is to stop MTAs being abused as
881 &"open relays"& by misguided individuals who send out vast amounts of
882 unsolicited junk, and want to disguise its source. Exim provides flexible
883 facilities for specifying policy controls on incoming mail:
885 .ilist
886 .cindex "&ACL;" "introduction"
887 Exim 4 (unlike previous versions of Exim) implements policy controls on
888 incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
889 series of statements that may either grant or deny access. ACLs can be used at
890 several places in the SMTP dialogue while receiving a message from a remote
891 host. However, the most common places are after each RCPT command, and at the
892 very end of the message. The sysadmin can specify conditions for accepting or
893 rejecting individual recipients or the entire message, respectively, at these
894 two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
895 error code.
896 .next
897 An ACL is also available for locally generated, non-SMTP messages. In this
898 case, the only available actions are to accept or deny the entire message.
899 .next
900 When Exim is compiled with the content-scanning extension, facilities are
901 provided in the ACL mechanism for passing the message to external virus and/or
902 spam scanning software. The result of such a scan is passed back to the ACL,
903 which can then use it to decide what to do with the message.
904 .next
905 When a message has been received, either from a remote host or from the local
906 host, but before the final acknowledgment has been sent, a locally supplied C
907 function called &[local_scan()]& can be run to inspect the message and decide
908 whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
909 is accepted, the list of recipients can be modified by the function.
910 .next
911 Using the &[local_scan()]& mechanism is another way of calling external scanner
912 software. The &%SA-Exim%& add-on package works this way. It does not require
913 Exim to be compiled with the content-scanning extension.
914 .next
915 After a message has been accepted, a further checking mechanism is available in
916 the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
917 runs at the start of every delivery process.
918 .endlist
922 .section "User filters" "SECID12"
923 .cindex "filter" "introduction"
924 .cindex "Sieve filter"
925 In a conventional Exim configuration, users are able to run private filters by
926 setting up appropriate &_.forward_& files in their home directories. See
927 chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
928 configuration needed to support this, and the separate document entitled
929 &'Exim's interfaces to mail filtering'& for user details. Two different kinds
930 of filtering are available:
932 .ilist
933 Sieve filters are written in the standard filtering language that is defined
934 by RFC 3028.
935 .next
936 Exim filters are written in a syntax that is unique to Exim, but which is more
937 powerful than Sieve, which it pre-dates.
938 .endlist
940 User filters are run as part of the routing process, described below.
944 .section "Message identification" "SECTmessiden"
945 .cindex "message ids" "details of format"
946 .cindex "format" "of message id"
947 .cindex "id of message"
948 .cindex "base62"
949 .cindex "base36"
950 .cindex "Darwin"
951 .cindex "Cygwin"
952 Every message handled by Exim is given a &'message id'& which is sixteen
953 characters long. It is divided into three parts, separated by hyphens, for
954 example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
955 normally encoding numbers in base 62. However, in the Darwin operating
956 system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
957 (avoiding the use of lower case letters) is used instead, because the message
958 id is used to construct file names, and the names of files in those systems are
959 not always case-sensitive.
961 .cindex "pid (process id)" "re-use of"
962 The detail of the contents of the message id have changed as Exim has evolved.
963 Earlier versions relied on the operating system not re-using a process id (pid)
964 within one second. On modern operating systems, this assumption can no longer
965 be made, so the algorithm had to be changed. To retain backward compatibility,
966 the format of the message id was retained, which is why the following rules are
967 somewhat eccentric:
969 .ilist
970 The first six characters of the message id are the time at which the message
971 started to be received, to a granularity of one second. That is, this field
972 contains the number of seconds since the start of the epoch (the normal Unix
973 way of representing the date and time of day).
974 .next
975 After the first hyphen, the next six characters are the id of the process that
976 received the message.
977 .next
978 There are two different possibilities for the final two characters:
979 .olist
980 .oindex "&%localhost_number%&"
981 If &%localhost_number%& is not set, this value is the fractional part of the
982 time of reception, normally in units of 1/2000 of a second, but for systems
983 that must use base 36 instead of base 62 (because of case-insensitive file
984 systems), the units are 1/1000 of a second.
985 .next
986 If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
987 the fractional part of the time, which in this case is in units of 1/200
988 (1/100) of a second.
989 .endlist
990 .endlist
992 After a message has been received, Exim waits for the clock to tick at the
993 appropriate resolution before proceeding, so that if another message is
994 received by the same process, or by another process with the same (re-used)
995 pid, it is guaranteed that the time will be different. In most cases, the clock
996 will already have ticked while the message was being received.
999 .section "Receiving mail" "SECID13"
1000 .cindex "receiving mail"
1001 .cindex "message" "reception"
1002 The only way Exim can receive mail from another host is using SMTP over
1003 TCP/IP, in which case the sender and recipient addresses are transferred using
1004 SMTP commands. However, from a locally running process (such as a user's MUA),
1005 there are several possibilities:
1007 .ilist
1008 If the process runs Exim with the &%-bm%& option, the message is read
1009 non-interactively (usually via a pipe), with the recipients taken from the
1010 command line, or from the body of the message if &%-t%& is also used.
1011 .next
1012 If the process runs Exim with the &%-bS%& option, the message is also read
1013 non-interactively, but in this case the recipients are listed at the start of
1014 the message in a series of SMTP RCPT commands, terminated by a DATA
1015 command. This is so-called &"batch SMTP"& format,
1016 but it isn't really SMTP. The SMTP commands are just another way of passing
1017 envelope addresses in a non-interactive submission.
1018 .next
1019 If the process runs Exim with the &%-bs%& option, the message is read
1020 interactively, using the SMTP protocol. A two-way pipe is normally used for
1021 passing data between the local process and the Exim process.
1022 This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
1023 example, the ACLs for SMTP commands are used for this form of submission.
1024 .next
1025 A local process may also make a TCP/IP call to the host's loopback address
1026 ( or any other of its IP addresses. When receiving messages, Exim
1027 does not treat the loopback address specially. It treats all such connections
1028 in the same way as connections from other hosts.
1029 .endlist
1032 .cindex "message sender, constructed by Exim"
1033 .cindex "sender" "constructed by Exim"
1034 In the three cases that do not involve TCP/IP, the sender address is
1035 constructed from the login name of the user that called Exim and a default
1036 qualification domain (which can be set by the &%qualify_domain%& configuration
1037 option). For local or batch SMTP, a sender address that is passed using the
1038 SMTP MAIL command is ignored. However, the system administrator may allow
1039 certain users (&"trusted users"&) to specify a different sender address
1040 unconditionally, or all users to specify certain forms of different sender
1041 address. The &%-f%& option or the SMTP MAIL command is used to specify these
1042 different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1043 users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
1044 users to change sender addresses.
1046 Messages received by either of the non-interactive mechanisms are subject to
1047 checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1048 (either over TCP/IP, or interacting with a local process) can be checked by a
1049 number of ACLs that operate at different times during the SMTP session. Either
1050 individual recipients, or the entire message, can be rejected if local policy
1051 requirements are not met. The &[local_scan()]& function (see chapter
1052 &<<CHAPlocalscan>>&) is run for all incoming messages.
1054 Exim can be configured not to start a delivery process when a message is
1055 received; this can be unconditional, or depend on the number of incoming SMTP
1056 connections or the system load. In these situations, new messages wait on the
1057 queue until a queue runner process picks them up. However, in standard
1058 configurations under normal conditions, delivery is started as soon as a
1059 message is received.
1065 .section "Handling an incoming message" "SECID14"
1066 .cindex "spool directory" "files that hold a message"
1067 .cindex "file" "how a message is held"
1068 When Exim accepts a message, it writes two files in its spool directory. The
1069 first contains the envelope information, the current status of the message, and
1070 the header lines, and the second contains the body of the message. The names of
1071 the two spool files consist of the message id, followed by &`-H`& for the
1072 file containing the envelope and header, and &`-D`& for the data file.
1074 .cindex "spool directory" "&_input_& sub-directory"
1075 By default all these message files are held in a single directory called
1076 &_input_& inside the general Exim spool directory. Some operating systems do
1077 not perform very well if the number of files in a directory gets large; to
1078 improve performance in such cases, the &%split_spool_directory%& option can be
1079 used. This causes Exim to split up the input files into 62 sub-directories
1080 whose names are single letters or digits. When this is done, the queue is
1081 processed one sub-directory at a time instead of all at once, which can improve
1082 overall performance even when there are not enough files in each directory to
1083 affect file system performance.
1085 The envelope information consists of the address of the message's sender and
1086 the addresses of the recipients. This information is entirely separate from
1087 any addresses contained in the header lines. The status of the message includes
1088 a list of recipients who have already received the message. The format of the
1089 first spool file is described in chapter &<<CHAPspool>>&.
1091 .cindex "rewriting" "addresses"
1092 Address rewriting that is specified in the rewrite section of the configuration
1093 (see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
1094 both in the header lines and the envelope, at the time the message is accepted.
1095 If during the course of delivery additional addresses are generated (for
1096 example, via aliasing), these new addresses are rewritten as soon as they are
1097 generated. At the time a message is actually delivered (transported) further
1098 rewriting can take place; because this is a transport option, it can be
1099 different for different forms of delivery. It is also possible to specify the
1100 addition or removal of certain header lines at the time the message is
1101 delivered (see chapters &<<CHAProutergeneric>>& and
1102 &<<CHAPtransportgeneric>>&).
1106 .section "Life of a message" "SECID15"
1107 .cindex "message" "life of"
1108 .cindex "message" "frozen"
1109 A message remains in the spool directory until it is completely delivered to
1110 its recipients or to an error address, or until it is deleted by an
1111 administrator or by the user who originally created it. In cases when delivery
1112 cannot proceed &-- for example, when a message can neither be delivered to its
1113 recipients nor returned to its sender, the message is marked &"frozen"& on the
1114 spool, and no more deliveries are attempted.
1116 .cindex "frozen messages" "thawing"
1117 .cindex "message" "thawing frozen"
1118 An administrator can &"thaw"& such messages when the problem has been
1119 corrected, and can also freeze individual messages by hand if necessary. In
1120 addition, an administrator can force a delivery error, causing a bounce message
1121 to be sent.
1123 .oindex "&%timeout_frozen_after%&"
1124 .oindex "&%ignore_bounce_errors_after%&"
1125 There are options called &%ignore_bounce_errors_after%& and
1126 &%timeout_frozen_after%&, which discard frozen messages after a certain time.
1127 The first applies only to frozen bounces, the second to any frozen messages.
1129 .cindex "message" "log file for"
1130 .cindex "log" "file for each message"
1131 While Exim is working on a message, it writes information about each delivery
1132 attempt to its main log file. This includes successful, unsuccessful, and
1133 delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1134 lines are also written to a separate &'message log'& file for each message.
1135 These logs are solely for the benefit of the administrator, and are normally
1136 deleted along with the spool files when processing of a message is complete.
1137 The use of individual message logs can be disabled by setting
1138 &%no_message_logs%&; this might give an improvement in performance on very busy
1139 systems.
1141 .cindex "journal file"
1142 .cindex "file" "journal"
1143 All the information Exim itself needs to set up a delivery is kept in the first
1144 spool file, along with the header lines. When a successful delivery occurs, the
1145 address is immediately written at the end of a journal file, whose name is the
1146 message id followed by &`-J`&. At the end of a delivery run, if there are some
1147 addresses left to be tried again later, the first spool file (the &`-H`& file)
1148 is updated to indicate which these are, and the journal file is then deleted.
1149 Updating the spool file is done by writing a new file and renaming it, to
1150 minimize the possibility of data loss.
1152 Should the system or the program crash after a successful delivery but before
1153 the spool file has been updated, the journal is left lying around. The next
1154 time Exim attempts to deliver the message, it reads the journal file and
1155 updates the spool file before proceeding. This minimizes the chances of double
1156 deliveries caused by crashes.
1160 .section "Processing an address for delivery" "SECTprocaddress"
1161 .cindex "drivers" "definition of"
1162 .cindex "router" "definition of"
1163 .cindex "transport" "definition of"
1164 The main delivery processing elements of Exim are called &'routers'& and
1165 &'transports'&, and collectively these are known as &'drivers'&. Code for a
1166 number of them is provided in the source distribution, and compile-time options
1167 specify which ones are included in the binary. Run time options specify which
1168 ones are actually used for delivering messages.
1170 .cindex "drivers" "instance definition"
1171 Each driver that is specified in the run time configuration is an &'instance'&
1172 of that particular driver type. Multiple instances are allowed; for example,
1173 you can set up several different &(smtp)& transports, each with different
1174 option values that might specify different ports or different timeouts. Each
1175 instance has its own identifying name. In what follows we will normally use the
1176 instance name when discussing one particular instance (that is, one specific
1177 configuration of the driver), and the generic driver name when discussing
1178 the driver's features in general.
1180 A &'router'& is a driver that operates on an address, either determining how
1181 its delivery should happen, by assigning it to a specific transport, or
1182 converting the address into one or more new addresses (for example, via an
1183 alias file). A router may also explicitly choose to fail an address, causing it
1184 to be bounced.
1186 A &'transport'& is a driver that transmits a copy of the message from Exim's
1187 spool to some destination. There are two kinds of transport: for a &'local'&
1188 transport, the destination is a file or a pipe on the local host, whereas for a
1189 &'remote'& transport the destination is some other host. A message is passed
1190 to a specific transport as a result of successful routing. If a message has
1191 several recipients, it may be passed to a number of different transports.
1193 .cindex "preconditions" "definition of"
1194 An address is processed by passing it to each configured router instance in
1195 turn, subject to certain preconditions, until a router accepts the address or
1196 specifies that it should be bounced. We will describe this process in more
1197 detail shortly. First, as a simple example, we consider how each recipient
1198 address in a message is processed in a small configuration of three routers.
1200 To make this a more concrete example, it is described in terms of some actual
1201 routers, but remember, this is only an example. You can configure Exim's
1202 routers in many different ways, and there may be any number of routers in a
1203 configuration.
1205 The first router that is specified in a configuration is often one that handles
1206 addresses in domains that are not recognized specially by the local host. These
1207 are typically addresses for arbitrary domains on the Internet. A precondition
1208 is set up which looks for the special domains known to the host (for example,
1209 its own domain name), and the router is run for addresses that do &'not'&
1210 match. Typically, this is a router that looks up domains in the DNS in order to
1211 find the hosts to which this address routes. If it succeeds, the address is
1212 assigned to a suitable SMTP transport; if it does not succeed, the router is
1213 configured to fail the address.
1215 The second router is reached only when the domain is recognized as one that
1216 &"belongs"& to the local host. This router does redirection &-- also known as
1217 aliasing and forwarding. When it generates one or more new addresses from the
1218 original, each of them is routed independently from the start. Otherwise, the
1219 router may cause an address to fail, or it may simply decline to handle the
1220 address, in which case the address is passed to the next router.
1222 The final router in many configurations is one that checks to see if the
1223 address belongs to a local mailbox. The precondition may involve a check to
1224 see if the local part is the name of a login account, or it may look up the
1225 local part in a file or a database. If its preconditions are not met, or if
1226 the router declines, we have reached the end of the routers. When this happens,
1227 the address is bounced.
1231 .section "Processing an address for verification" "SECID16"
1232 .cindex "router" "for verification"
1233 .cindex "verifying address" "overview"
1234 As well as being used to decide how to deliver to an address, Exim's routers
1235 are also used for &'address verification'&. Verification can be requested as
1236 one of the checks to be performed in an ACL for incoming messages, on both
1237 sender and recipient addresses, and it can be tested using the &%-bv%& and
1238 &%-bvs%& command line options.
1240 When an address is being verified, the routers are run in &"verify mode"&. This
1241 does not affect the way the routers work, but it is a state that can be
1242 detected. By this means, a router can be skipped or made to behave differently
1243 when verifying. A common example is a configuration in which the first router
1244 sends all messages to a message-scanning program, unless they have been
1245 previously scanned. Thus, the first router accepts all addresses without any
1246 checking, making it useless for verifying. Normally, the &%no_verify%& option
1247 would be set for such a router, causing it to be skipped in verify mode.
1252 .section "Running an individual router" "SECTrunindrou"
1253 .cindex "router" "running details"
1254 .cindex "preconditions" "checking"
1255 .cindex "router" "result of running"
1256 As explained in the example above, a number of preconditions are checked before
1257 running a router. If any are not met, the router is skipped, and the address is
1258 passed to the next router. When all the preconditions on a router &'are'& met,
1259 the router is run. What happens next depends on the outcome, which is one of
1260 the following:
1262 .ilist
1263 &'accept'&: The router accepts the address, and either assigns it to a
1264 transport, or generates one or more &"child"& addresses. Processing the
1265 original address ceases,
1266 .oindex "&%unseen%&"
1267 unless the &%unseen%& option is set on the router. This option
1268 can be used to set up multiple deliveries with different routing (for example,
1269 for keeping archive copies of messages). When &%unseen%& is set, the address is
1270 passed to the next router. Normally, however, an &'accept'& return marks the
1271 end of routing.
1273 Any child addresses generated by the router are processed independently,
1274 starting with the first router by default. It is possible to change this by
1275 setting the &%redirect_router%& option to specify which router to start at for
1276 child addresses. Unlike &%pass_router%& (see below) the router specified by
1277 &%redirect_router%& may be anywhere in the router configuration.
1278 .next
1279 &'pass'&: The router recognizes the address, but cannot handle it itself. It
1280 requests that the address be passed to another router. By default the address
1281 is passed to the next router, but this can be changed by setting the
1282 &%pass_router%& option. However, (unlike &%redirect_router%&) the named router
1283 must be below the current router (to avoid loops).
1284 .next
1285 &'decline'&: The router declines to accept the address because it does not
1286 recognize it at all. By default, the address is passed to the next router, but
1287 this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1288 set, all the remaining routers are skipped. In effect, &%no_more%& converts
1289 &'decline'& into &'fail'&.
1290 .next
1291 &'fail'&: The router determines that the address should fail, and queues it for
1292 the generation of a bounce message. There is no further processing of the
1293 original address unless &%unseen%& is set on the router.
1294 .next
1295 &'defer'&: The router cannot handle the address at the present time. (A
1296 database may be offline, or a DNS lookup may have timed out.) No further
1297 processing of the address happens in this delivery attempt. It is tried again
1298 next time the message is considered for delivery.
1299 .next
1300 &'error'&: There is some error in the router (for example, a syntax error in
1301 its configuration). The action is as for defer.
1302 .endlist
1304 If an address reaches the end of the routers without having been accepted by
1305 any of them, it is bounced as unrouteable. The default error message in this
1306 situation is &"unrouteable address"&, but you can set your own message by
1307 making use of the &%cannot_route_message%& option. This can be set for any
1308 router; the value from the last router that &"saw"& the address is used.
1310 Sometimes while routing you want to fail a delivery when some conditions are
1311 met but others are not, instead of passing the address on for further routing.
1312 You can do this by having a second router that explicitly fails the delivery
1313 when the relevant conditions are met. The &(redirect)& router has a &"fail"&
1314 facility for this purpose.
1317 .section "Duplicate addresses" "SECID17"
1318 .cindex "case of local parts"
1319 .cindex "address duplicate, discarding"
1320 .cindex "duplicate addresses"
1321 Once routing is complete, Exim scans the addresses that are assigned to local
1322 and remote transports, and discards any duplicates that it finds. During this
1323 check, local parts are treated as case-sensitive. This happens only when
1324 actually delivering a message; when testing routers with &%-bt%&, all the
1325 routed addresses are shown.
1329 .section "Router preconditions" "SECTrouprecon"
1330 .cindex "router" "preconditions, order of processing"
1331 .cindex "preconditions" "order of processing"
1332 The preconditions that are tested for each router are listed below, in the
1333 order in which they are tested. The individual configuration options are
1334 described in more detail in chapter &<<CHAProutergeneric>>&.
1336 .ilist
1337 The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
1338 the local parts handled by the router may or must have certain prefixes and/or
1339 suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1340 skipped. These conditions are tested first. When an affix is present, it is
1341 removed from the local part before further processing, including the evaluation
1342 of any other conditions.
1343 .next
1344 Routers can be designated for use only when not verifying an address, that is,
1345 only when routing it for delivery (or testing its delivery routing). If the
1346 &%verify%& option is set false, the router is skipped when Exim is verifying an
1347 address.
1348 Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1349 &%verify_recipient%&, which independently control the use of the router for
1350 sender and recipient verification. You can set these options directly if
1351 you want a router to be used for only one type of verification.
1352 .next
1353 If the &%address_test%& option is set false, the router is skipped when Exim is
1354 run with the &%-bt%& option to test an address routing. This can be helpful
1355 when the first router sends all new messages to a scanner of some sort; it
1356 makes it possible to use &%-bt%& to test subsequent delivery routing without
1357 having to simulate the effect of the scanner.
1358 .next
1359 Routers can be designated for use only when verifying an address, as
1360 opposed to routing it for delivery. The &%verify_only%& option controls this.
1361 .next
1362 Individual routers can be explicitly skipped when running the routers to
1363 check an address given in the SMTP EXPN command (see the &%expn%& option).
1364 .next
1365 If the &%domains%& option is set, the domain of the address must be in the set
1366 of domains that it defines.
1367 .next
1368 .vindex "&$local_part_prefix$&"
1369 .vindex "&$local_part$&"
1370 .vindex "&$local_part_suffix$&"
1371 If the &%local_parts%& option is set, the local part of the address must be in
1372 the set of local parts that it defines. If &%local_part_prefix%& or
1373 &%local_part_suffix%& is in use, the prefix or suffix is removed from the local
1374 part before this check. If you want to do precondition tests on local parts
1375 that include affixes, you can do so by using a &%condition%& option (see below)
1376 that uses the variables &$local_part$&, &$local_part_prefix$&, and
1377 &$local_part_suffix$& as necessary.
1378 .next
1379 .vindex "&$local_user_uid$&"
1380 .vindex "&$local_user_gid$&"
1381 .vindex "&$home$&"
1382 If the &%check_local_user%& option is set, the local part must be the name of
1383 an account on the local host. If this check succeeds, the uid and gid of the
1384 local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1385 user's home directory is placed in &$home$&; these values can be used in the
1386 remaining preconditions.
1387 .next
1388 If the &%router_home_directory%& option is set, it is expanded at this point,
1389 because it overrides the value of &$home$&. If this expansion were left till
1390 later, the value of &$home$& as set by &%check_local_user%& would be used in
1391 subsequent tests. Having two different values of &$home$& in the same router
1392 could lead to confusion.
1393 .next
1394 If the &%senders%& option is set, the envelope sender address must be in the
1395 set of addresses that it defines.
1396 .next
1397 If the &%require_files%& option is set, the existence or non-existence of
1398 specified files is tested.
1399 .next
1400 .cindex "customizing" "precondition"
1401 If the &%condition%& option is set, it is evaluated and tested. This option
1402 uses an expanded string to allow you to set up your own custom preconditions.
1403 Expanded strings are described in chapter &<<CHAPexpand>>&.
1404 .endlist
1407 Note that &%require_files%& comes near the end of the list, so you cannot use
1408 it to check for the existence of a file in which to lookup up a domain, local
1409 part, or sender. However, as these options are all expanded, you can use the
1410 &%exists%& expansion condition to make such tests within each condition. The
1411 &%require_files%& option is intended for checking files that the router may be
1412 going to use internally, or which are needed by a specific transport (for
1413 example, &_.procmailrc_&).
1417 .section "Delivery in detail" "SECID18"
1418 .cindex "delivery" "in detail"
1419 When a message is to be delivered, the sequence of events is as follows:
1421 .ilist
1422 If a system-wide filter file is specified, the message is passed to it. The
1423 filter may add recipients to the message, replace the recipients, discard the
1424 message, cause a new message to be generated, or cause the message delivery to
1425 fail. The format of the system filter file is the same as for Exim user filter
1426 files, described in the separate document entitled &'Exim's interfaces to mail
1427 filtering'&.
1428 .cindex "Sieve filter" "not available for system filter"
1429 (&*Note*&: Sieve cannot be used for system filter files.)
1431 Some additional features are available in system filters &-- see chapter
1432 &<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
1433 filter only once per delivery attempt, however many recipients it has. However,
1434 if there are several delivery attempts because one or more addresses could not
1435 be immediately delivered, the system filter is run each time. The filter
1436 condition &%first_delivery%& can be used to detect the first run of the system
1437 filter.
1438 .next
1439 Each recipient address is offered to each configured router in turn, subject to
1440 its preconditions, until one is able to handle it. If no router can handle the
1441 address, that is, if they all decline, the address is failed. Because routers
1442 can be targeted at particular domains, several locally handled domains can be
1443 processed entirely independently of each other.
1444 .next
1445 .cindex "routing" "loops in"
1446 .cindex "loop" "while routing"
1447 A router that accepts an address may assign it to a local or a remote
1448 transport. However, the transport is not run at this time. Instead, the address
1449 is placed on a list for the particular transport, which will be run later.
1450 Alternatively, the router may generate one or more new addresses (typically
1451 from alias, forward, or filter files). New addresses are fed back into this
1452 process from the top, but in order to avoid loops, a router ignores any address
1453 which has an identically-named ancestor that was processed by itself.
1454 .next
1455 When all the routing has been done, addresses that have been successfully
1456 handled are passed to their assigned transports. When local transports are
1457 doing real local deliveries, they handle only one address at a time, but if a
1458 local transport is being used as a pseudo-remote transport (for example, to
1459 collect batched SMTP messages for transmission by some other means) multiple
1460 addresses can be handled. Remote transports can always handle more than one
1461 address at a time, but can be configured not to do so, or to restrict multiple
1462 addresses to the same domain.
1463 .next
1464 Each local delivery to a file or a pipe runs in a separate process under a
1465 non-privileged uid, and these deliveries are run one at a time. Remote
1466 deliveries also run in separate processes, normally under a uid that is private
1467 to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
1468 run in parallel. The maximum number of simultaneous remote deliveries for any
1469 one message is set by the &%remote_max_parallel%& option.
1470 The order in which deliveries are done is not defined, except that all local
1471 deliveries happen before any remote deliveries.
1472 .next
1473 .cindex "queue runner"
1474 When it encounters a local delivery during a queue run, Exim checks its retry
1475 database to see if there has been a previous temporary delivery failure for the
1476 address before running the local transport. If there was a previous failure,
1477 Exim does not attempt a new delivery until the retry time for the address is
1478 reached. However, this happens only for delivery attempts that are part of a
1479 queue run. Local deliveries are always attempted when delivery immediately
1480 follows message reception, even if retry times are set for them. This makes for
1481 better behaviour if one particular message is causing problems (for example,
1482 causing quota overflow, or provoking an error in a filter file).
1483 .next
1484 .cindex "delivery" "retry in remote transports"
1485 Remote transports do their own retry handling, since an address may be
1486 deliverable to one of a number of hosts, each of which may have a different
1487 retry time. If there have been previous temporary failures and no host has
1488 reached its retry time, no delivery is attempted, whether in a queue run or
1489 not. See chapter &<<CHAPretry>>& for details of retry strategies.
1490 .next
1491 If there were any permanent errors, a bounce message is returned to an
1492 appropriate address (the sender in the common case), with details of the error
1493 for each failing address. Exim can be configured to send copies of bounce
1494 messages to other addresses.
1495 .next
1496 .cindex "delivery" "deferral"
1497 If one or more addresses suffered a temporary failure, the message is left on
1498 the queue, to be tried again later. Delivery of these addresses is said to be
1499 &'deferred'&.
1500 .next
1501 When all the recipient addresses have either been delivered or bounced,
1502 handling of the message is complete. The spool files and message log are
1503 deleted, though the message log can optionally be preserved if required.
1504 .endlist
1509 .section "Retry mechanism" "SECID19"
1510 .cindex "delivery" "retry mechanism"
1511 .cindex "retry" "description of mechanism"
1512 .cindex "queue runner"
1513 Exim's mechanism for retrying messages that fail to get delivered at the first
1514 attempt is the queue runner process. You must either run an Exim daemon that
1515 uses the &%-q%& option with a time interval to start queue runners at regular
1516 intervals, or use some other means (such as &'cron'&) to start them. If you do
1517 not arrange for queue runners to be run, messages that fail temporarily at the
1518 first attempt will remain on your queue for ever. A queue runner process works
1519 its way through the queue, one message at a time, trying each delivery that has
1520 passed its retry time.
1521 You can run several queue runners at once.
1523 Exim uses a set of configured rules to determine when next to retry the failing
1524 address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1525 should give up trying to deliver to the address, at which point it generates a
1526 bounce message. If no retry rules are set for a particular host, address, and
1527 error combination, no retries are attempted, and temporary errors are treated
1528 as permanent.
1532 .section "Temporary delivery failure" "SECID20"
1533 .cindex "delivery" "temporary failure"
1534 There are many reasons why a message may not be immediately deliverable to a
1535 particular address. Failure to connect to a remote machine (because it, or the
1536 connection to it, is down) is one of the most common. Temporary failures may be
1537 detected during routing as well as during the transport stage of delivery.
1538 Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1539 is on a file system where the user is over quota. Exim can be configured to
1540 impose its own quotas on local mailboxes; where system quotas are set they will
1541 also apply.
1543 If a host is unreachable for a period of time, a number of messages may be
1544 waiting for it by the time it recovers, and sending them in a single SMTP
1545 connection is clearly beneficial. Whenever a delivery to a remote host is
1546 deferred,
1547 .cindex "hints database"
1548 Exim makes a note in its hints database, and whenever a successful
1549 SMTP delivery has happened, it looks to see if any other messages are waiting
1550 for the same host. If any are found, they are sent over the same SMTP
1551 connection, subject to a configuration limit as to the maximum number in any
1552 one connection.
1557 .section "Permanent delivery failure" "SECID21"
1558 .cindex "delivery" "permanent failure"
1559 .cindex "bounce message" "when generated"
1560 When a message cannot be delivered to some or all of its intended recipients, a
1561 bounce message is generated. Temporary delivery failures turn into permanent
1562 errors when their timeout expires. All the addresses that fail in a given
1563 delivery attempt are listed in a single message. If the original message has
1564 many recipients, it is possible for some addresses to fail in one delivery
1565 attempt and others to fail subsequently, giving rise to more than one bounce
1566 message. The wording of bounce messages can be customized by the administrator.
1567 See chapter &<<CHAPemsgcust>>& for details.
1569 .cindex "&'X-Failed-Recipients:'& header line"
1570 Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
1571 failed addresses, for the benefit of programs that try to analyse such messages
1572 automatically.
1574 .cindex "bounce message" "recipient of"
1575 A bounce message is normally sent to the sender of the original message, as
1576 obtained from the message's envelope. For incoming SMTP messages, this is the
1577 address given in the MAIL command. However, when an address is expanded via a
1578 forward or alias file, an alternative address can be specified for delivery
1579 failures of the generated addresses. For a mailing list expansion (see section
1580 &<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1581 of the list.
1585 .section "Failures to deliver bounce messages" "SECID22"
1586 .cindex "bounce message" "failure to deliver"
1587 If a bounce message (either locally generated or received from a remote host)
1588 itself suffers a permanent delivery failure, the message is left on the queue,
1589 but it is frozen, awaiting the attention of an administrator. There are options
1590 that can be used to make Exim discard such failed messages, or to keep them
1591 for only a short time (see &%timeout_frozen_after%& and
1592 &%ignore_bounce_errors_after%&).
1598 . ////////////////////////////////////////////////////////////////////////////
1599 . ////////////////////////////////////////////////////////////////////////////
1601 .chapter "Building and installing Exim" "CHID3"
1602 .scindex IIDbuex "building Exim"
1604 .section "Unpacking" "SECID23"
1605 Exim is distributed as a gzipped or bzipped tar file which, when unpacked,
1606 creates a directory with the name of the current release (for example,
1607 &_exim-&version;_&) into which the following files are placed:
1609 .table2 140pt
1610 .irow &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1611 .irow &_CHANGES_& "contains a reference to where changes are &&&
1612 documented"
1613 .irow &_LICENCE_& "the GNU General Public Licence"
1614 .irow &_Makefile_& "top-level make file"
1615 .irow &_NOTICE_& "conditions for the use of Exim"
1616 .irow &_README_& "list of files, directories and simple build &&&
1617 instructions"
1618 .endtable
1620 Other files whose names begin with &_README_& may also be present. The
1621 following subdirectories are created:
1623 .table2 140pt
1624 .irow &_Local_& "an empty directory for local configuration files"
1625 .irow &_OS_& "OS-specific files"
1626 .irow &_doc_& "documentation files"
1627 .irow &_exim_monitor_& "source files for the Exim monitor"
1628 .irow &_scripts_& "scripts used in the build process"
1629 .irow &_src_& "remaining source files"
1630 .irow &_util_& "independent utilities"
1631 .endtable
1633 The main utility programs are contained in the &_src_& directory, and are built
1634 with the Exim binary. The &_util_& directory contains a few optional scripts
1635 that may be useful to some sites.
1638 .section "Multiple machine architectures and operating systems" "SECID24"
1639 .cindex "building Exim" "multiple OS/architectures"
1640 The building process for Exim is arranged to make it easy to build binaries for
1641 a number of different architectures and operating systems from the same set of
1642 source files. Compilation does not take place in the &_src_& directory.
1643 Instead, a &'build directory'& is created for each architecture and operating
1644 system.
1645 .cindex "symbolic link" "to build directory"
1646 Symbolic links to the sources are installed in this directory, which is where
1647 the actual building takes place. In most cases, Exim can discover the machine
1648 architecture and operating system for itself, but the defaults can be
1649 overridden if necessary.
1652 .section "PCRE library" "SECTpcre"
1653 .cindex "PCRE library"
1654 Exim no longer has an embedded PCRE library as the vast majority of
1655 modern systems include PCRE as a system library, although you may need
1656 to install the PCRE or PCRE development package for your operating
1657 system. If your system has a normal PCRE installation the Exim build
1658 process will need no further configuration. If the library or the
1659 headers are in an unusual location you will need to set the PCRE_LIBS
1660 and INCLUDE directives appropriately. If your operating system has no
1661 PCRE support then you will need to obtain and build the current PCRE
1662 from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/).
1664 .section "DBM libraries" "SECTdb"
1665 .cindex "DBM libraries" "discussion of"
1666 .cindex "hints database" "DBM files used for"
1667 Even if you do not use any DBM files in your configuration, Exim still needs a
1668 DBM library in order to operate, because it uses indexed files for its hints
1669 databases. Unfortunately, there are a number of DBM libraries in existence, and
1670 different operating systems often have different ones installed.
1672 .cindex "Solaris" "DBM library for"
1673 .cindex "IRIX, DBM library for"
1674 .cindex "BSD, DBM library for"
1675 .cindex "Linux, DBM library for"
1676 If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1677 Linux distribution, the DBM configuration should happen automatically, and you
1678 may be able to ignore this section. Otherwise, you may have to learn more than
1679 you would like about DBM libraries from what follows.
1681 .cindex "&'ndbm'& DBM library"
1682 Licensed versions of Unix normally contain a library of DBM functions operating
1683 via the &'ndbm'& interface, and this is what Exim expects by default. Free
1684 versions of Unix seem to vary in what they contain as standard. In particular,
1685 some early versions of Linux have no default DBM library, and different
1686 distributors have chosen to bundle different libraries with their packaged
1687 versions. However, the more recent releases seem to have standardized on the
1688 Berkeley DB library.
1690 Different DBM libraries have different conventions for naming the files they
1691 use. When a program opens a file called &_dbmfile_&, there are several
1692 possibilities:
1694 .olist
1695 A traditional &'ndbm'& implementation, such as that supplied as part of
1696 Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1697 .next
1698 .cindex "&'gdbm'& DBM library"
1699 The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
1700 compatibility interface it makes two different hard links to it with names
1701 &_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
1702 file name is used unmodified.
1703 .next
1704 .cindex "Berkeley DB library"
1705 The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1706 operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1707 programmer exactly the same as the traditional &'ndbm'& implementation.
1708 .next
1709 If the Berkeley package is used in its native mode, it operates on a single
1710 file called &_dbmfile_&; the programmer's interface is somewhat different to
1711 the traditional &'ndbm'& interface.
1712 .next
1713 To complicate things further, there are several very different versions of the
1714 Berkeley DB package. Version 1.85 was stable for a very long time, releases
1715 2.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1716 numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
1717 versions of Berkeley DB can be obtained from
1718 &url(http://www.sleepycat.com/).
1719 .next
1720 .cindex "&'tdb'& DBM library"
1721 Yet another DBM library, called &'tdb'&, is available from
1722 &url(http://download.sourceforge.net/tdb). It has its own interface, and also
1723 operates on a single file.
1724 .endlist
1726 .cindex "USE_DB"
1727 .cindex "DBM libraries" "configuration for building"
1728 Exim and its utilities can be compiled to use any of these interfaces. In order
1729 to use any version of the Berkeley DB package in native mode, you must set
1730 USE_DB in an appropriate configuration file (typically
1731 &_Local/Makefile_&). For example:
1732 .code
1733 USE_DB=yes
1734 .endd
1735 Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1736 error is diagnosed if you set more than one of these.
1738 At the lowest level, the build-time configuration sets none of these options,
1739 thereby assuming an interface of type (1). However, some operating system
1740 configuration files (for example, those for the BSD operating systems and
1741 Linux) assume type (4) by setting USE_DB as their default, and the
1742 configuration files for Cygwin set USE_GDBM. Anything you set in
1743 &_Local/Makefile_&, however, overrides these system defaults.
1745 As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1746 necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1747 in one of these lines:
1748 .code
1749 DBMLIB = -ldb
1750 DBMLIB = -ltdb
1751 .endd
1752 Settings like that will work if the DBM library is installed in the standard
1753 place. Sometimes it is not, and the library's header file may also not be in
1754 the default path. You may need to set INCLUDE to specify where the header
1755 file is, and to specify the path to the library more fully in DBMLIB, as in
1756 this example:
1757 .code
1758 INCLUDE=-I/usr/local/include/db-4.1
1759 DBMLIB=/usr/local/lib/db-4.1/libdb.a
1760 .endd
1761 There is further detailed discussion about the various DBM libraries in the
1762 file &_doc/dbm.discuss.txt_& in the Exim distribution.
1766 .section "Pre-building configuration" "SECID25"
1767 .cindex "building Exim" "pre-building configuration"
1768 .cindex "configuration for building Exim"
1769 .cindex "&_Local/Makefile_&"
1770 .cindex "&_src/EDITME_&"
1771 Before building Exim, a local configuration file that specifies options
1772 independent of any operating system has to be created with the name
1773 &_Local/Makefile_&. A template for this file is supplied as the file
1774 &_src/EDITME_&, and it contains full descriptions of all the option settings
1775 therein. These descriptions are therefore not repeated here. If you are
1776 building Exim for the first time, the simplest thing to do is to copy
1777 &_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
1779 There are three settings that you must supply, because Exim will not build
1780 without them. They are the location of the run time configuration file
1781 (CONFIGURE_FILE), the directory in which Exim binaries will be installed
1782 (BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1783 maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1784 a colon-separated list of file names; Exim uses the first of them that exists.
1786 There are a few other parameters that can be specified either at build time or
1787 at run time, to enable the same binary to be used on a number of different
1788 machines. However, if the locations of Exim's spool directory and log file
1789 directory (if not within the spool directory) are fixed, it is recommended that
1790 you specify them in &_Local/Makefile_& instead of at run time, so that errors
1791 detected early in Exim's execution (such as a malformed configuration file) can
1792 be logged.
1794 .cindex "content scanning" "specifying at build time"
1795 Exim's interfaces for calling virus and spam scanning software directly from
1796 access control lists are not compiled by default. If you want to include these
1797 facilities, you need to set
1798 .code
1800 .endd
1801 in your &_Local/Makefile_&. For details of the facilities themselves, see
1802 chapter &<<CHAPexiscan>>&.
1805 .cindex "&_Local/eximon.conf_&"
1806 .cindex "&_exim_monitor/EDITME_&"
1807 If you are going to build the Exim monitor, a similar configuration process is
1808 required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1809 your installation and saved under the name &_Local/eximon.conf_&. If you are
1810 happy with the default settings described in &_exim_monitor/EDITME_&,
1811 &_Local/eximon.conf_& can be empty, but it must exist.
1813 This is all the configuration that is needed in straightforward cases for known
1814 operating systems. However, the building process is set up so that it is easy
1815 to override options that are set by default or by operating-system-specific
1816 configuration files, for example to change the name of the C compiler, which
1817 defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1818 do this.
1822 .section "Support for iconv()" "SECID26"
1823 .cindex "&[iconv()]& support"
1824 .cindex "RFC 2047"
1825 The contents of header lines in messages may be encoded according to the rules
1826 described RFC 2047. This makes it possible to transmit characters that are not
1827 in the ASCII character set, and to label them as being in a particular
1828 character set. When Exim is inspecting header lines by means of the &%$h_%&
1829 mechanism, it decodes them, and translates them into a specified character set
1830 (default ISO-8859-1). The translation is possible only if the operating system
1831 supports the &[iconv()]& function.
1833 However, some of the operating systems that supply &[iconv()]& do not support
1834 very many conversions. The GNU &%libiconv%& library (available from
1835 &url(http://www.gnu.org/software/libiconv/)) can be installed on such
1836 systems to remedy this deficiency, as well as on systems that do not supply
1837 &[iconv()]& at all. After installing &%libiconv%&, you should add
1838 .code
1839 HAVE_ICONV=yes
1840 .endd
1841 to your &_Local/Makefile_& and rebuild Exim.
1845 .section "Including TLS/SSL encryption support" "SECTinctlsssl"
1846 .cindex "TLS" "including support for TLS"
1847 .cindex "encryption" "including support for"
1848 .cindex "SUPPORT_TLS"
1849 .cindex "OpenSSL" "building Exim with"
1850 .cindex "GnuTLS" "building Exim with"
1851 Exim can be built to support encrypted SMTP connections, using the STARTTLS
1852 command as per RFC 2487. It can also support legacy clients that expect to
1853 start a TLS session immediately on connection to a non-standard port (see the
1854 &%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
1855 line option).
1857 If you want to build Exim with TLS support, you must first install either the
1858 OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1859 implementing SSL.
1861 If OpenSSL is installed, you should set
1862 .code
1863 SUPPORT_TLS=yes
1864 TLS_LIBS=-lssl -lcrypto
1865 .endd
1866 in &_Local/Makefile_&. You may also need to specify the locations of the
1867 OpenSSL library and include files. For example:
1868 .code
1869 SUPPORT_TLS=yes
1870 TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1871 TLS_INCLUDE=-I/usr/local/openssl/include/
1872 .endd
1873 .cindex "USE_GNUTLS"
1874 If GnuTLS is installed, you should set
1875 .code
1876 SUPPORT_TLS=yes
1877 USE_GNUTLS=yes
1878 TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1879 .endd
1880 in &_Local/Makefile_&, and again you may need to specify the locations of the
1881 library and include files. For example:
1882 .code
1883 SUPPORT_TLS=yes
1884 USE_GNUTLS=yes
1885 TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1886 TLS_INCLUDE=-I/usr/gnu/include
1887 .endd
1888 You do not need to set TLS_INCLUDE if the relevant directory is already
1889 specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1890 given in chapter &<<CHAPTLS>>&.
1895 .section "Use of tcpwrappers" "SECID27"
1896 .new
1897 .cindex "tcpwrappers, building Exim to support"
1898 .cindex "USE_TCP_WRAPPERS"
1900 .cindex "tcp_wrappers_daemon_name"
1901 Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1902 SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
1903 alternative to Exim's own checking facilities for installations that are
1904 already making use of &'tcpwrappers'& for other purposes. To do this, you
1905 should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1906 &_tcpd.h_& to be available at compile time, and also ensure that the library
1907 &_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1908 EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1909 you might have
1910 .code
1912 CFLAGS=-O -I/usr/local/include
1913 EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1914 .endd
1915 in &_Local/Makefile_&. The daemon name to use in the &'tcpwrappers'& control
1916 files is &"exim"&. For example, the line
1917 .code
1918 exim : LOCAL 192.168.1. .friendly.domain.example
1919 .endd
1920 in your &_/etc/hosts.allow_& file allows connections from the local host, from
1921 the subnet, and from all hosts in &'friendly.domain.example'&.
1922 All other connections are denied. The daemon name used by &'tcpwrappers'&
1923 can be changed at build time by setting TCP_WRAPPERS_DAEMON_NAME in
1924 in &_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the
1925 configure file. Consult the &'tcpwrappers'& documentation for
1926 further details.
1927 .wen
1930 .section "Including support for IPv6" "SECID28"
1931 .cindex "IPv6" "including support for"
1932 Exim contains code for use on systems that have IPv6 support. Setting
1933 &`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
1934 it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1935 where the IPv6 support is not fully integrated into the normal include and
1936 library files.
1938 Two different types of DNS record for handling IPv6 addresses have been
1939 defined. AAAA records (analogous to A records for IPv4) are in use, and are
1940 currently seen as the mainstream. Another record type called A6 was proposed
1941 as better than AAAA because it had more flexibility. However, it was felt to be
1942 over-complex, and its status was reduced to &"experimental"&. It is not known
1943 if anyone is actually using A6 records. Exim has support for A6 records, but
1944 this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
1945 support has not been tested for some time.
1949 .section "The building process" "SECID29"
1950 .cindex "build directory"
1951 Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
1952 created, run &'make'& at the top level. It determines the architecture and
1953 operating system types, and creates a build directory if one does not exist.
1954 For example, on a Sun system running Solaris 8, the directory
1955 &_build-SunOS5-5.8-sparc_& is created.
1956 .cindex "symbolic link" "to source files"
1957 Symbolic links to relevant source files are installed in the build directory.
1959 &*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
1960 building process fails if it is set.
1962 If this is the first time &'make'& has been run, it calls a script that builds
1963 a make file inside the build directory, using the configuration files from the
1964 &_Local_& directory. The new make file is then passed to another instance of
1965 &'make'&. This does the real work, building a number of utility scripts, and
1966 then compiling and linking the binaries for the Exim monitor (if configured), a
1967 number of utility programs, and finally Exim itself. The command &`make
1968 makefile`& can be used to force a rebuild of the make file in the build
1969 directory, should this ever be necessary.
1971 If you have problems building Exim, check for any comments there may be in the
1972 &_README_& file concerning your operating system, and also take a look at the
1973 FAQ, where some common problems are covered.
1977 .section 'Output from &"make"&' "SECID283"
1978 The output produced by the &'make'& process for compile lines is often very
1979 unreadable, because these lines can be very long. For this reason, the normal
1980 output is suppressed by default, and instead output similar to that which
1981 appears when compiling the 2.6 Linux kernel is generated: just a short line for
1982 each module that is being compiled or linked. However, it is still possible to
1983 get the full output, by calling &'make'& like this:
1984 .code
1985 FULLECHO='' make -e
1986 .endd
1987 The value of FULLECHO defaults to &"@"&, the flag character that suppresses
1988 command reflection in &'make'&. When you ask for the full output, it is
1989 given in addition to the short output.
1993 .section "Overriding build-time options for Exim" "SECToverride"
1994 .cindex "build-time options, overriding"
1995 The main make file that is created at the beginning of the building process
1996 consists of the concatenation of a number of files which set configuration
1997 values, followed by a fixed set of &'make'& instructions. If a value is set
1998 more than once, the last setting overrides any previous ones. This provides a
1999 convenient way of overriding defaults. The files that are concatenated are, in
2000 order:
2001 .display
2002 &_OS/Makefile-Default_&
2003 &_OS/Makefile-_&<&'ostype'&>
2004 &_Local/Makefile_&
2005 &_Local/Makefile-_&<&'ostype'&>
2006 &_Local/Makefile-_&<&'archtype'&>
2007 &_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
2008 &_OS/Makefile-Base_&
2009 .endd
2010 .cindex "&_Local/Makefile_&"
2011 .cindex "building Exim" "operating system type"
2012 .cindex "building Exim" "architecture type"
2013 where <&'ostype'&> is the operating system type and <&'archtype'&> is the
2014 architecture type. &_Local/Makefile_& is required to exist, and the building
2015 process fails if it is absent. The other three &_Local_& files are optional,
2016 and are often not needed.
2018 The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
2019 called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
2020 the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
2021 values are used, thereby providing a means of forcing particular settings.
2022 Otherwise, the scripts try to get values from the &%uname%& command. If this
2023 fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
2024 of &'ad hoc'& transformations are then applied, to produce the standard names
2025 that Exim expects. You can run these scripts directly from the shell in order
2026 to find out what values are being used on your system.
2029 &_OS/Makefile-Default_& contains comments about the variables that are set
2030 therein. Some (but not all) are mentioned below. If there is something that
2031 needs changing, review the contents of this file and the contents of the make
2032 file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
2033 default values are.
2036 .cindex "building Exim" "overriding default settings"
2037 If you need to change any of the values that are set in &_OS/Makefile-Default_&
2038 or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
2039 need to change the original files. Instead, you should make the changes by
2040 putting the new values in an appropriate &_Local_& file. For example,
2041 .cindex "Tru64-Unix build-time settings"
2042 when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2043 formerly DEC-OSF1) operating system, it is necessary to specify that the C
2044 compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2045 called with the option &%-std1%&, to make it recognize some of the features of
2046 Standard C that Exim uses. (Most other compilers recognize Standard C by
2047 default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
2048 containing the lines
2049 .code
2050 CC=cc
2051 CFLAGS=-std1
2052 .endd
2053 If you are compiling for just one operating system, it may be easier to put
2054 these lines directly into &_Local/Makefile_&.
2056 Keeping all your local configuration settings separate from the distributed
2057 files makes it easy to transfer them to new versions of Exim simply by copying
2058 the contents of the &_Local_& directory.
2061 .cindex "NIS lookup type" "including support for"
2062 .cindex "NIS+ lookup type" "including support for"
2063 .cindex "LDAP" "including support for"
2064 .cindex "lookup" "inclusion in binary"
2065 Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2066 lookup, but not all systems have these components installed, so the default is
2067 not to include the relevant code in the binary. All the different kinds of file
2068 and database lookup that Exim supports are implemented as separate code modules
2069 which are included only if the relevant compile-time options are set. In the
2070 case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2071 .code
2072 LOOKUP_LDAP=yes
2073 LOOKUP_NIS=yes
2075 .endd
2076 and similar settings apply to the other lookup types. They are all listed in
2077 &_src/EDITME_&. In many cases the relevant include files and interface
2078 libraries need to be installed before compiling Exim.
2079 .cindex "cdb" "including support for"
2080 However, there are some optional lookup types (such as cdb) for which
2081 the code is entirely contained within Exim, and no external include
2082 files or libraries are required. When a lookup type is not included in the
2083 binary, attempts to configure Exim to use it cause run time configuration
2084 errors.
2086 .cindex "Perl" "including support for"
2087 Exim can be linked with an embedded Perl interpreter, allowing Perl
2088 subroutines to be called during string expansion. To enable this facility,
2089 .code
2090 EXIM_PERL=perl.o
2091 .endd
2092 must be defined in &_Local/Makefile_&. Details of this facility are given in
2093 chapter &<<CHAPperl>>&.
2095 .cindex "X11 libraries, location of"
2096 The location of the X11 libraries is something that varies a lot between
2097 operating systems, and there may be different versions of X11 to cope
2098 with. Exim itself makes no use of X11, but if you are compiling the Exim
2099 monitor, the X11 libraries must be available.
2100 The following three variables are set in &_OS/Makefile-Default_&:
2101 .code
2102 X11=/usr/X11R6
2103 XINCLUDE=-I$(X11)/include
2104 XLFLAGS=-L$(X11)/lib
2105 .endd
2106 These are overridden in some of the operating-system configuration files. For
2107 example, in &_OS/Makefile-SunOS5_& there is
2108 .code
2109 X11=/usr/openwin
2110 XINCLUDE=-I$(X11)/include
2111 XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2112 .endd
2113 If you need to override the default setting for your operating system, place a
2114 definition of all three of these variables into your
2115 &_Local/Makefile-<ostype>_& file.
2117 .cindex "EXTRALIBS"
2118 If you need to add any extra libraries to the link steps, these can be put in a
2119 variable called EXTRALIBS, which appears in all the link commands, but by
2120 default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2121 command for linking the main Exim binary, and not for any associated utilities.
2123 .cindex "DBM libraries" "configuration for building"
2124 There is also DBMLIB, which appears in the link commands for binaries that
2125 use DBM functions (see also section &<<SECTdb>>&). Finally, there is
2126 EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2127 binary, and which can be used, for example, to include additional X11
2128 libraries.
2130 .cindex "configuration file" "editing"
2131 The make file copes with rebuilding Exim correctly if any of the configuration
2132 files are edited. However, if an optional configuration file is deleted, it is
2133 necessary to touch the associated non-optional file (that is,
2134 &_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
2137 .section "OS-specific header files" "SECID30"
2138 .cindex "&_os.h_&"
2139 .cindex "building Exim" "OS-specific C header files"
2140 The &_OS_& directory contains a number of files with names of the form
2141 &_os.h-<ostype>_&. These are system-specific C header files that should not
2142 normally need to be changed. There is a list of macro settings that are
2143 recognized in the file &_OS/os.configuring_&, which should be consulted if you
2144 are porting Exim to a new operating system.
2148 .section "Overriding build-time options for the monitor" "SECID31"
2149 .cindex "building Eximon"
2150 A similar process is used for overriding things when building the Exim monitor,
2151 where the files that are involved are
2152 .display
2153 &_OS/eximon.conf-Default_&
2154 &_OS/eximon.conf-_&<&'ostype'&>
2155 &_Local/eximon.conf_&
2156 &_Local/eximon.conf-_&<&'ostype'&>
2157 &_Local/eximon.conf-_&<&'archtype'&>
2158 &_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2159 .endd
2160 .cindex "&_Local/eximon.conf_&"
2161 As with Exim itself, the final three files need not exist, and in this case the
2162 &_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2163 &_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
2164 variables of the same name, preceded by EXIMON_. For example, setting
2165 EXIMON_LOG_DEPTH in the environment overrides the value of
2166 LOG_DEPTH at run time.
2167 .ecindex IIDbuex
2170 .section "Installing Exim binaries and scripts" "SECID32"
2171 .cindex "installing Exim"
2172 .cindex "BIN_DIRECTORY"
2173 The command &`make install`& runs the &(exim_install)& script with no
2174 arguments. The script copies binaries and utility scripts into the directory
2175 whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2176 .cindex "setuid" "installing Exim with"
2177 The install script copies files only if they are newer than the files they are
2178 going to replace. The Exim binary is required to be owned by root and have the
2179 &'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2180 install`& as root so that it can set up the Exim binary in this way. However, in
2181 some special situations (for example, if a host is doing no local deliveries)
2182 it may be possible to run Exim without making the binary setuid root (see
2183 chapter &<<CHAPsecurity>>& for details).
2185 .cindex "CONFIGURE_FILE"
2186 Exim's run time configuration file is named by the CONFIGURE_FILE setting
2187 in &_Local/Makefile_&. If this names a single file, and the file does not
2188 exist, the default configuration file &_src/configure.default_& is copied there
2189 by the installation script. If a run time configuration file already exists, it
2190 is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2191 alternative files, no default is installed.
2193 .cindex "system aliases file"
2194 .cindex "&_/etc/aliases_&"
2195 One change is made to the default configuration file when it is installed: the
2196 default configuration contains a router that references a system aliases file.
2197 The path to this file is set to the value specified by
2198 SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
2199 If the system aliases file does not exist, the installation script creates it,
2200 and outputs a comment to the user.
2202 The created file contains no aliases, but it does contain comments about the
2203 aliases a site should normally have. Mail aliases have traditionally been
2204 kept in &_/etc/aliases_&. However, some operating systems are now using
2205 &_/etc/mail/aliases_&. You should check if yours is one of these, and change
2206 Exim's configuration if necessary.
2208 The default configuration uses the local host's name as the only local domain,
2209 and is set up to do local deliveries into the shared directory &_/var/mail_&,
2210 running as the local user. System aliases and &_.forward_& files in users' home
2211 directories are supported, but no NIS or NIS+ support is configured. Domains
2212 other than the name of the local host are routed using the DNS, with delivery
2213 over SMTP.
2215 It is possible to install Exim for special purposes (such as building a binary
2216 distribution) in a private part of the file system. You can do this by a
2217 command such as
2218 .code
2219 make DESTDIR=/some/directory/ install
2220 .endd
2221 This has the effect of pre-pending the specified directory to all the file
2222 paths, except the name of the system aliases file that appears in the default
2223 configuration. (If a default alias file is created, its name &'is'& modified.)
2224 For backwards compatibility, ROOT is used if DESTDIR is not set,
2225 but this usage is deprecated.
2227 .cindex "installing Exim" "what is not installed"
2228 Running &'make install'& does not copy the Exim 4 conversion script
2229 &'convert4r4'&. You will probably run this only once if you are
2230 upgrading from Exim 3. None of the documentation files in the &_doc_&
2231 directory are copied, except for the info files when you have set
2232 INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
2234 For the utility programs, old versions are renamed by adding the suffix &_.O_&
2235 to their names. The Exim binary itself, however, is handled differently. It is
2236 installed under a name that includes the version number and the compile number,
2237 for example &_exim-&version;-1_&. The script then arranges for a symbolic link
2238 called &_exim_& to point to the binary. If you are updating a previous version
2239 of Exim, the script takes care to ensure that the name &_exim_& is never absent
2240 from the directory (as seen by other processes).
2242 .cindex "installing Exim" "testing the script"
2243 If you want to see what the &'make install'& will do before running it for
2244 real, you can pass the &%-n%& option to the installation script by this
2245 command:
2246 .code
2247 make INSTALL_ARG=-n install
2248 .endd
2249 The contents of the variable INSTALL_ARG are passed to the installation
2250 script. You do not need to be root to run this test. Alternatively, you can run
2251 the installation script directly, but this must be from within the build
2252 directory. For example, from the top-level Exim directory you could use this
2253 command:
2254 .code
2255 (cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2256 .endd
2257 .cindex "installing Exim" "install script options"
2258 There are two other options that can be supplied to the installation script.
2260 .ilist
2261 &%-no_chown%& bypasses the call to change the owner of the installed binary
2262 to root, and the call to make it a setuid binary.
2263 .next
2264 &%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
2265 installed binary.
2266 .endlist
2268 INSTALL_ARG can be used to pass these options to the script. For example:
2269 .code
2270 make INSTALL_ARG=-no_symlink install
2271 .endd
2272 The installation script can also be given arguments specifying which files are
2273 to be copied. For example, to install just the Exim binary, and nothing else,
2274 without creating the symbolic link, you could use:
2275 .code
2276 make INSTALL_ARG='-no_symlink exim' install
2277 .endd
2281 .section "Installing info documentation" "SECTinsinfdoc"
2282 .cindex "installing Exim" "&'info'& documentation"
2283 Not all systems use the GNU &'info'& system for documentation, and for this
2284 reason, the Texinfo source of Exim's documentation is not included in the main
2285 distribution. Instead it is available separately from the ftp site (see section
2286 &<<SECTavail>>&).
2288 If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2289 source of the documentation is found in the source tree, running &`make
2290 install`& automatically builds the info files and installs them.
2294 .section "Setting up the spool directory" "SECID33"
2295 .cindex "spool directory" "creating"
2296 When it starts up, Exim tries to create its spool directory if it does not
2297 exist. The Exim uid and gid are used for the owner and group of the spool
2298 directory. Sub-directories are automatically created in the spool directory as
2299 necessary.
2304 .section "Testing" "SECID34"
2305 .cindex "testing" "installation"
2306 Having installed Exim, you can check that the run time configuration file is
2307 syntactically valid by running the following command, which assumes that the
2308 Exim binary directory is within your PATH environment variable:
2309 .code
2310 exim -bV
2311 .endd
2312 If there are any errors in the configuration file, Exim outputs error messages.
2313 Otherwise it outputs the version number and build date,
2314 the DBM library that is being used, and information about which drivers and
2315 other optional code modules are included in the binary.
2316 Some simple routing tests can be done by using the address testing option. For
2317 example,
2318 .display
2319 &`exim -bt`& <&'local username'&>
2320 .endd
2321 should verify that it recognizes a local mailbox, and
2322 .display
2323 &`exim -bt`& <&'remote address'&>
2324 .endd
2325 a remote one. Then try getting it to deliver mail, both locally and remotely.
2326 This can be done by passing messages directly to Exim, without going through a
2327 user agent. For example:
2328 .code
2329 exim -v postmaster@your.domain.example
2330 From: user@your.domain.example
2331 To: postmaster@your.domain.example
2332 Subject: Testing Exim
2334 This is a test message.
2335 ^D
2336 .endd
2337 The &%-v%& option causes Exim to output some verification of what it is doing.
2338 In this case you should see copies of three log lines, one for the message's
2339 arrival, one for its delivery, and one containing &"Completed"&.
2341 .cindex "delivery" "problems with"
2342 If you encounter problems, look at Exim's log files (&'mainlog'& and
2343 &'paniclog'&) to see if there is any relevant information there. Another source
2344 of information is running Exim with debugging turned on, by specifying the
2345 &%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
2346 with debugging turned on by a command of the form
2347 .display
2348 &`exim -d -M`& <&'exim-message-id'&>
2349 .endd
2350 You must be root or an &"admin user"& in order to do this. The &%-d%& option
2351 produces rather a lot of output, but you can cut this down to specific areas.
2352 For example, if you use &%-d-all+route%& only the debugging information
2353 relevant to routing is included. (See the &%-d%& option in chapter
2354 &<<CHAPcommandline>>& for more details.)
2356 .cindex '&"sticky"& bit'
2357 .cindex "lock files"
2358 One specific problem that has shown up on some sites is the inability to do
2359 local deliveries into a shared mailbox directory, because it does not have the
2360 &"sticky bit"& set on it. By default, Exim tries to create a lock file before
2361 writing to a mailbox file, and if it cannot create the lock file, the delivery
2362 is deferred. You can get round this either by setting the &"sticky bit"& on the
2363 directory, or by setting a specific group for local deliveries and allowing
2364 that group to create files in the directory (see the comments above the
2365 &(local_delivery)& transport in the default configuration file). Another
2366 approach is to configure Exim not to use lock files, but just to rely on
2367 &[fcntl()]& locking instead. However, you should do this only if all user
2368 agents also use &[fcntl()]& locking. For further discussion of locking issues,
2369 see chapter &<<CHAPappendfile>>&.
2371 One thing that cannot be tested on a system that is already running an MTA is
2372 the receipt of incoming SMTP mail on the standard SMTP port. However, the
2373 &%-oX%& option can be used to run an Exim daemon that listens on some other
2374 port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2375 &'exim_checkaccess'& utility can be used to check out policy controls on
2376 incoming SMTP mail.
2378 Testing a new version on a system that is already running Exim can most easily
2379 be done by building a binary with a different CONFIGURE_FILE setting. From
2380 within the run time configuration, all other file and directory names
2381 that Exim uses can be altered, in order to keep it entirely clear of the
2382 production version.
2385 .section "Replacing another MTA with Exim" "SECID35"
2386 .cindex "replacing another MTA"
2387 Building and installing Exim for the first time does not of itself put it in
2388 general use. The name by which the system's MTA is called by mail user agents
2389 is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2390 operating system), and it is necessary to make this name point to the &'exim'&
2391 binary in order to get the user agents to pass messages to Exim. This is
2392 normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2393 or &_/usr/lib/sendmail_&
2394 .cindex "symbolic link" "to &'exim'& binary"
2395 a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
2396 privilege and executable status from the old MTA. It is then necessary to stop
2397 and restart the mailer daemon, if one is running.
2399 .cindex "FreeBSD, MTA indirection"
2400 .cindex "&_/etc/mail/mailer.conf_&"
2401 Some operating systems have introduced alternative ways of switching MTAs. For
2402 example, if you are running FreeBSD, you need to edit the file
2403 &_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
2404 described. A typical example of the contents of this file for running Exim is
2405 as follows:
2406 .code
2407 sendmail /usr/exim/bin/exim
2408 send-mail /usr/exim/bin/exim
2409 mailq /usr/exim/bin/exim -bp
2410 newaliases /usr/bin/true
2411 .endd
2412 Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2413 your Exim installation is &"live"&. Check it by sending a message from your
2414 favourite user agent.
2416 You should consider what to tell your users about the change of MTA. Exim may
2417 have different capabilities to what was previously running, and there are
2418 various operational differences such as the text of messages produced by
2419 command line options and in bounce messages. If you allow your users to make
2420 use of Exim's filtering capabilities, you should make the document entitled
2421 &'Exim's interface to mail filtering'& available to them.
2425 .section "Upgrading Exim" "SECID36"
2426 .cindex "upgrading Exim"
2427 If you are already running Exim on your host, building and installing a new
2428 version automatically makes it available to MUAs, or any other programs that
2429 call the MTA directly. However, if you are running an Exim daemon, you do need
2430 to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2431 new binary. You do not need to stop processing mail in order to install a new
2432 version of Exim. The install script does not modify an existing runtime
2433 configuration file.
2438 .section "Stopping the Exim daemon on Solaris" "SECID37"
2439 .cindex "Solaris" "stopping Exim on"
2440 The standard command for stopping the mailer daemon on Solaris is
2441 .code
2442 /etc/init.d/sendmail stop
2443 .endd
2444 If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2445 fails to stop Exim because it uses the command &'ps -e'& and greps the output
2446 for the text &"sendmail"&; this is not present because the actual program name
2447 (that is, &"exim"&) is given by the &'ps'& command with these options. A
2448 solution is to replace the line that finds the process id with something like
2449 .code
2450 pid=`cat /var/spool/exim/exim-daemon.pid`
2451 .endd
2452 to obtain the daemon's pid directly from the file that Exim saves it in.
2454 Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
2455 still be received from local processes, and if automatic delivery is configured
2456 (the normal case), deliveries will still occur.
2461 . ////////////////////////////////////////////////////////////////////////////
2462 . ////////////////////////////////////////////////////////////////////////////
2464 .chapter "The Exim command line" "CHAPcommandline"
2465 .scindex IIDclo1 "command line" "options"
2466 .scindex IIDclo2 "options" "command line"
2467 Exim's command line takes the standard Unix form of a sequence of options,
2468 each starting with a hyphen character, followed by a number of arguments. The
2469 options are compatible with the main options of Sendmail, and there are also
2470 some additional options, some of which are compatible with Smail 3. Certain
2471 combinations of options do not make sense, and provoke an error if used.
2472 The form of the arguments depends on which options are set.
2475 .section "Setting options by program name" "SECID38"
2476 .cindex "&'mailq'&"
2477 If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
2478 were present before any other options.
2479 The &%-bp%& option requests a listing of the contents of the mail queue on the
2480 standard output.
2481 This feature is for compatibility with some systems that contain a command of
2482 that name in one of the standard libraries, symbolically linked to
2483 &_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2485 .cindex "&'rsmtp'&"
2486 If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2487 were present before any other options, for compatibility with Smail. The
2488 &%-bS%& option is used for reading in a number of messages in batched SMTP
2489 format.
2491 .cindex "&'rmail'&"
2492 If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2493 &%-oee%& options were present before any other options, for compatibility with
2494 Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2496 .cindex "&'runq'&"
2497 .cindex "queue runner"
2498 If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2499 were present before any other options, for compatibility with Smail. The &%-q%&
2500 option causes a single queue runner process to be started.
2502 .cindex "&'newaliases'&"
2503 .cindex "alias file" "building"
2504 .cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2505 If Exim is called under the name &'newaliases'& it behaves as if the option
2506 &%-bi%& were present before any other options, for compatibility with Sendmail.
2507 This option is used for rebuilding Sendmail's alias file. Exim does not have
2508 the concept of a single alias file, but can be configured to run a given
2509 command if called with the &%-bi%& option.
2512 .section "Trusted and admin users" "SECTtrustedadmin"
2513 Some Exim options are available only to &'trusted users'& and others are
2514 available only to &'admin users'&. In the description below, the phrases &"Exim
2515 user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2516 EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2517 &%exim_group%& options. These do not necessarily have to use the name &"exim"&.
2519 .ilist
2520 .cindex "trusted users" "definition of"
2521 .cindex "user" "trusted definition of"
2522 The trusted users are root, the Exim user, any user listed in the
2523 &%trusted_users%& configuration option, and any user whose current group or any
2524 supplementary group is one of those listed in the &%trusted_groups%&
2525 configuration option. Note that the Exim group is not automatically trusted.
2527 .cindex '&"From"& line'
2528 .cindex "envelope sender"
2529 Trusted users are always permitted to use the &%-f%& option or a leading
2530 &"From&~"& line to specify the envelope sender of a message that is passed to
2531 Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2532 See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2533 users to set envelope senders.
2535 .cindex "&'From:'& header line"
2536 .cindex "&'Sender:'& header line"
2537 For a trusted user, there is never any check on the contents of the &'From:'&
2538 header line, and a &'Sender:'& line is never added. Furthermore, any existing
2539 &'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2541 Trusted users may also specify a host name, host address, interface address,
2542 protocol name, ident value, and authentication data when submitting a message
2543 locally. Thus, they are able to insert messages into Exim's queue locally that
2544 have the characteristics of messages received from a remote host. Untrusted
2545 users may in some circumstances use &%-f%&, but can never set the other values
2546 that are available to trusted users.
2547 .next
2548 .cindex "user" "admin definition of"
2549 .cindex "admin user" "definition of"
2550 The admin users are root, the Exim user, and any user that is a member of the
2551 Exim group or of any group listed in the &%admin_groups%& configuration option.
2552 The current group does not have to be one of these groups.
2554 Admin users are permitted to list the queue, and to carry out certain
2555 operations on messages, for example, to force delivery failures. It is also
2556 necessary to be an admin user in order to see the full information provided by
2557 the Exim monitor, and full debugging output.
2559 By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2560 Exim to attempt delivery of messages on its queue is restricted to admin users.
2561 However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2562 option false (that is, specifying &%no_prod_requires_admin%&).
2564 Similarly, the use of the &%-bp%& option to list all the messages in the queue
2565 is restricted to admin users unless &%queue_list_requires_admin%& is set
2566 false.
2567 .endlist
2570 &*Warning*&: If you configure your system so that admin users are able to
2571 edit Exim's configuration file, you are giving those users an easy way of
2572 getting root. There is further discussion of this issue at the start of chapter
2573 &<<CHAPconf>>&.
2578 .section "Command line options" "SECID39"
2579 Exim's command line options are described in alphabetical order below. If none
2580 of the options that specifies a specific action (such as starting the daemon or
2581 a queue runner, or testing an address, or receiving a message in a specific
2582 format, or listing the queue) are present, and there is at least one argument
2583 on the command line, &%-bm%& (accept a local message on the standard input,
2584 with the arguments specifying the recipients) is assumed. Otherwise, Exim
2585 outputs a brief message about itself and exits.
2587 . ////////////////////////////////////////////////////////////////////////////
2588 . Insert a stylized XML comment here, to identify the start of the command line
2589 . options. This is for the benefit of the Perl script that automatically
2590 . creates a man page for the options.
2591 . ////////////////////////////////////////////////////////////////////////////
2593 .literal xml
2594 <!-- === Start of command line options === -->
2595 .literal off
2598 .vlist
2599 .vitem &%--%&
2600 .oindex "--"
2601 .cindex "options" "command line; terminating"
2602 This is a pseudo-option whose only purpose is to terminate the options and
2603 therefore to cause subsequent command line items to be treated as arguments
2604 rather than options, even if they begin with hyphens.
2606 .vitem &%--help%&
2607 .oindex "&%--help%&"
2608 This option causes Exim to output a few sentences stating what it is.
2609 The same output is generated if the Exim binary is called with no options and
2610 no arguments.
2612 .new
2613 .vitem &%--version%&
2614 .oindex "&%--version%&"
2615 This option is an alias for &%-bV%& and causes version information to be
2616 displayed.
2617 .wen
2619 .vitem &%-B%&<&'type'&>
2620 .oindex "&%-B%&"
2621 .cindex "8-bit characters"
2622 .cindex "Sendmail compatibility" "8-bit characters"
2623 This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2624 clean; it ignores this option.
2626 .vitem &%-bd%&
2627 .oindex "&%-bd%&"
2628 .cindex "daemon"
2629 .cindex "SMTP" "listener"
2630 .cindex "queue runner"
2631 This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
2632 the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2633 that the daemon should also initiate periodic queue runs.
2635 The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2636 (debugging) or &%-v%& (verifying) options are set, the daemon does not
2637 disconnect from the controlling terminal. When running this way, it can be
2638 stopped by pressing ctrl-C.
2640 By default, Exim listens for incoming connections to the standard SMTP port on
2641 all the host's running interfaces. However, it is possible to listen on other
2642 ports, on multiple ports, and only on specific interfaces. Chapter
2643 &<<CHAPinterfaces>>& contains a description of the options that control this.
2645 When a listening daemon
2646 .cindex "daemon" "process id (pid)"
2647 .cindex "pid (process id)" "of daemon"
2648 is started without the use of &%-oX%& (that is, without overriding the normal
2649 configuration), it writes its process id to a file called &_exim-daemon.pid_&
2650 in Exim's spool directory. This location can be overridden by setting
2651 PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
2652 running as root.
2654 When &%-oX%& is used on the command line to start a listening daemon, the
2655 process id is not written to the normal pid file path. However, &%-oP%& can be
2656 used to specify a path on the command line if a pid file is required.
2658 The SIGHUP signal
2659 .cindex "SIGHUP"
2660 .cindex "daemon" "restarting"
2661 can be used to cause the daemon to re-execute itself. This should be done
2662 whenever Exim's configuration file, or any file that is incorporated into it by
2663 means of the &%.include%& facility, is changed, and also whenever a new version
2664 of Exim is installed. It is not necessary to do this when other files that are
2665 referenced from the configuration (for example, alias files) are changed,
2666 because these are reread each time they are used.
2668 .vitem &%-bdf%&
2669 .oindex "&%-bdf%&"
2670 This option has the same effect as &%-bd%& except that it never disconnects
2671 from the controlling terminal, even when no debugging is specified.
2673 .vitem &%-be%&
2674 .oindex "&%-be%&"
2675 .cindex "testing" "string expansion"
2676 .cindex "expansion" "testing"
2677 Run Exim in expansion testing mode. Exim discards its root privilege, to
2678 prevent ordinary users from using this mode to read otherwise inaccessible
2679 files. If no arguments are given, Exim runs interactively, prompting for lines
2680 of data. Otherwise, it processes each argument in turn.
2682 If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2683 to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2684 used without command line arguments. If successful, it uses the &[readline()]&
2685 function, which provides extensive line-editing facilities, for reading the
2686 test data. A line history is supported.
2688 Long expansion expressions can be split over several lines by using backslash
2689 continuations. As in Exim's run time configuration, white space at the start of
2690 continuation lines is ignored. Each argument or data line is passed through the
2691 string expansion mechanism, and the result is output. Variable values from the
2692 configuration file (for example, &$qualify_domain$&) are available, but no
2693 message-specific values (such as &$sender_domain$&) are set, because no message
2694 is being processed (but see &%-bem%& and &%-Mset%&).
2696 &*Note*&: If you use this mechanism to test lookups, and you change the data
2697 files or databases you are using, you must exit and restart Exim before trying
2698 the same lookup again. Otherwise, because each Exim process caches the results
2699 of lookups, you will just get the same result as before.
2701 .vitem &%-bem%&&~<&'filename'&>
2702 .oindex "&%-bem%&"
2703 .cindex "testing" "string expansion"
2704 .cindex "expansion" "testing"
2705 This option operates like &%-be%& except that it must be followed by the name
2706 of a file. For example:
2707 .code
2708 exim -bem /tmp/testmessage
2709 .endd
2710 The file is read as a message (as if receiving a locally-submitted non-SMTP
2711 message) before any of the test expansions are done. Thus, message-specific
2712 variables such as &$message_size$& and &$header_from:$& are available. However,
2713 no &'Received:'& header is added to the message. If the &%-t%& option is set,
2714 recipients are read from the headers in the normal way, and are shown in the
2715 &$recipients$& variable. Note that recipients cannot be given on the command
2716 line, because further arguments are taken as strings to expand (just like
2717 &%-be%&).
2719 .vitem &%-bF%&&~<&'filename'&>
2720 .oindex "&%-bF%&"
2721 .cindex "system filter" "testing"
2722 .cindex "testing" "system filter"
2723 This option is the same as &%-bf%& except that it assumes that the filter being
2724 tested is a system filter. The additional commands that are available only in
2725 system filters are recognized.
2727 .vitem &%-bf%&&~<&'filename'&>
2728 .oindex "&%-bf%&"
2729 .cindex "filter" "testing"
2730 .cindex "testing" "filter file"
2731 .cindex "forward file" "testing"
2732 .cindex "testing" "forward file"
2733 .cindex "Sieve filter" "testing"
2734 This option runs Exim in user filter testing mode; the file is the filter file
2735 to be tested, and a test message must be supplied on the standard input. If
2736 there are no message-dependent tests in the filter, an empty file can be
2737 supplied.
2739 If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2740 can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2741 filter and a user filter in the same run. For example:
2742 .code
2743 exim -bF /system/filter -bf /user/filter </test/message
2744 .endd
2745 This is helpful when the system filter adds header lines or sets filter
2746 variables that are used by the user filter.
2748 If the test filter file does not begin with one of the special lines
2749 .code
2750 # Exim filter
2751 # Sieve filter
2752 .endd
2753 it is taken to be a normal &_.forward_& file, and is tested for validity under
2754 that interpretation. See sections &<<SECTitenonfilred>>& to
2755 &<<SECTspecitredli>>& for a description of the possible contents of non-filter
2756 redirection lists.
2758 The result of an Exim command that uses &%-bf%&, provided no errors are
2759 detected, is a list of the actions that Exim would try to take if presented
2760 with the message for real. More details of filter testing are given in the
2761 separate document entitled &'Exim's interfaces to mail filtering'&.
2763 When testing a filter file,
2764 .cindex "&""From""& line"
2765 .cindex "envelope sender"
2766 .oindex "&%-f%&" "for filter testing"
2767 the envelope sender can be set by the &%-f%& option,
2768 or by a &"From&~"& line at the start of the test message. Various parameters
2769 that would normally be taken from the envelope recipient address of the message
2770 can be set by means of additional command line options (see the next four
2771 options).
2773 .vitem &%-bfd%&&~<&'domain'&>
2774 .oindex "&%-bfd%&"
2775 .vindex "&$qualify_domain$&"
2776 This sets the domain of the recipient address when a filter file is being
2777 tested by means of the &%-bf%& option. The default is the value of
2778 &$qualify_domain$&.
2780 .vitem &%-bfl%&&~<&'local&~part'&>
2781 .oindex "&%-bfl%&"
2782 This sets the local part of the recipient address when a filter file is being
2783 tested by means of the &%-bf%& option. The default is the username of the
2784 process that calls Exim. A local part should be specified with any prefix or
2785 suffix stripped, because that is how it appears to the filter when a message is
2786 actually being delivered.
2788 .vitem &%-bfp%&&~<&'prefix'&>
2789 .oindex "&%-bfp%&"
2790 This sets the prefix of the local part of the recipient address when a filter
2791 file is being tested by means of the &%-bf%& option. The default is an empty
2792 prefix.
2794 .vitem &%-bfs%&&~<&'suffix'&>
2795 .oindex "&%-bfs%&"
2796 This sets the suffix of the local part of the recipient address when a filter
2797 file is being tested by means of the &%-bf%& option. The default is an empty
2798 suffix.
2800 .vitem &%-bh%&&~<&'IP&~address'&>
2801 .oindex "&%-bh%&"
2802 .cindex "testing" "incoming SMTP"
2803 .cindex "SMTP" "testing incoming"
2804 .cindex "testing" "relay control"
2805 .cindex "relaying" "testing configuration"
2806 .cindex "policy control" "testing"
2807 .cindex "debugging" "&%-bh%& option"
2808 This option runs a fake SMTP session as if from the given IP address, using the
2809 standard input and output. The IP address may include a port number at the end,
2810 after a full stop. For example:
2811 .code
2812 exim -bh
2813 exim -bh fe80::a00:20ff:fe86:a061.5678
2814 .endd
2815 When an IPv6 address is given, it is converted into canonical form. In the case
2816 of the second example above, the value of &$sender_host_address$& after
2817 conversion to the canonical form is
2818 &`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2820 Comments as to what is going on are written to the standard error file. These
2821 include lines beginning with &"LOG"& for anything that would have been logged.
2822 This facility is provided for testing configuration options for incoming
2823 messages, to make sure they implement the required policy. For example, you can
2824 test your relay controls using &%-bh%&.
2826 &*Warning 1*&:
2827 .cindex "RFC 1413"
2828 You can test features of the configuration that rely on ident (RFC 1413)
2829 information by using the &%-oMt%& option. However, Exim cannot actually perform
2830 an ident callout when testing using &%-bh%& because there is no incoming SMTP
2831 connection.
2833 &*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2834 are also skipped when testing using &%-bh%&. If you want these callouts to
2835 occur, use &%-bhc%& instead.
2837 Messages supplied during the testing session are discarded, and nothing is
2838 written to any of the real log files. There may be pauses when DNS (and other)
2839 lookups are taking place, and of course these may time out. The &%-oMi%& option
2840 can be used to specify a specific IP interface and port if this is important,
2841 and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2842 session were authenticated.
2844 The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
2845 output just states whether a given recipient address from a given host is
2846 acceptable or not. See section &<<SECTcheckaccess>>&.
2848 Features such as authentication and encryption, where the client input is not
2849 plain text, cannot easily be tested with &%-bh%&. Instead, you should use a
2850 specialized SMTP test program such as
2851 &url(http://jetmore.org/john/code/#swaks,swaks).
2853 .vitem &%-bhc%&&~<&'IP&~address'&>
2854 .oindex "&%-bhc%&"
2855 This option operates in the same way as &%-bh%&, except that address
2856 verification callouts are performed if required. This includes consulting and
2857 updating the callout cache database.
2859 .vitem &%-bi%&
2860 .oindex "&%-bi%&"
2861 .cindex "alias file" "building"
2862 .cindex "building alias file"
2863 .cindex "Sendmail compatibility" "&%-bi%& option"
2864 Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
2865 Exim does not have the concept of a single alias file, and so it cannot mimic
2866 this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
2867 tend to appear in various scripts such as NIS make files, so the option must be
2868 recognized.
2870 If &%-bi%& is encountered, the command specified by the &%bi_command%&
2871 configuration option is run, under the uid and gid of the caller of Exim. If
2872 the &%-oA%& option is used, its value is passed to the command as an argument.
2873 The command set by &%bi_command%& may not contain arguments. The command can
2874 use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2875 if this is required. If the &%bi_command%& option is not set, calling Exim with
2876 &%-bi%& is a no-op.
2878 .vitem &%-bm%&
2879 .oindex "&%-bm%&"
2880 .cindex "local message reception"
2881 This option runs an Exim receiving process that accepts an incoming,
2882 locally-generated message on the current input. The recipients are given as the
2883 command arguments (except when &%-t%& is also present &-- see below). Each
2884 argument can be a comma-separated list of RFC 2822 addresses. This is the
2885 default option for selecting the overall action of an Exim call; it is assumed
2886 if no other conflicting option is present.
2888 If any addresses in the message are unqualified (have no domain), they are
2889 qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
2890 options, as appropriate. The &%-bnq%& option (see below) provides a way of
2891 suppressing this for special cases.
2893 Policy checks on the contents of local messages can be enforced by means of
2894 the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
2896 .cindex "return code" "for &%-bm%&"
2897 The return code is zero if the message is successfully accepted. Otherwise, the
2898 action is controlled by the &%-oe%&&'x'& option setting &-- see below.
2900 The format
2901 .cindex "message" "format"
2902 .cindex "format" "message"
2903 .cindex "&""From""& line"
2904 .cindex "UUCP" "&""From""& line"
2905 .cindex "Sendmail compatibility" "&""From""& line"
2906 of the message must be as defined in RFC 2822, except that, for
2907 compatibility with Sendmail and Smail, a line in one of the forms
2908 .code
2909 From sender Fri Jan 5 12:55 GMT 1997
2910 From sender Fri, 5 Jan 97 12:55:01
2911 .endd
2912 (with the weekday optional, and possibly with additional text after the date)
2913 is permitted to appear at the start of the message. There appears to be no
2914 authoritative specification of the format of this line. Exim recognizes it by
2915 matching against the regular expression defined by the &%uucp_from_pattern%&
2916 option, which can be changed if necessary.
2918 .oindex "&%-f%&" "overriding &""From""& line"
2919 The specified sender is treated as if it were given as the argument to the
2920 &%-f%& option, but if a &%-f%& option is also present, its argument is used in
2921 preference to the address taken from the message. The caller of Exim must be a
2922 trusted user for the sender of a message to be set in this way.
2924 .vitem &%-bnq%&
2925 .oindex "&%-bnq%&"
2926 .cindex "address qualification, suppressing"
2927 By default, Exim automatically qualifies unqualified addresses (those
2928 without domains) that appear in messages that are submitted locally (that
2929 is, not over TCP/IP). This qualification applies both to addresses in
2930 envelopes, and addresses in header lines. Sender addresses are qualified using
2931 &%qualify_domain%&, and recipient addresses using &%qualify_recipient%& (which
2932 defaults to the value of &%qualify_domain%&).
2934 Sometimes, qualification is not wanted. For example, if &%-bS%& (batch SMTP) is
2935 being used to re-submit messages that originally came from remote hosts after
2936 content scanning, you probably do not want to qualify unqualified addresses in
2937 header lines. (Such lines will be present only if you have not enabled a header
2938 syntax check in the appropriate ACL.)
2940 The &%-bnq%& option suppresses all qualification of unqualified addresses in
2941 messages that originate on the local host. When this is used, unqualified
2942 addresses in the envelope provoke errors (causing message rejection) and
2943 unqualified addresses in header lines are left alone.
2946 .vitem &%-bP%&
2947 .oindex "&%-bP%&"
2948 .cindex "configuration options" "extracting"
2949 .cindex "options" "configuration &-- extracting"
2950 If this option is given with no arguments, it causes the values of all Exim's
2951 main configuration options to be written to the standard output. The values
2952 of one or more specific options can be requested by giving their names as
2953 arguments, for example:
2954 .code
2955 exim -bP qualify_domain hold_domains
2956 .endd
2957 .cindex "hiding configuration option values"
2958 .cindex "configuration options" "hiding value of"
2959 .cindex "options" "hiding value of"
2960 However, any option setting that is preceded by the word &"hide"& in the
2961 configuration file is not shown in full, except to an admin user. For other
2962 users, the output is as in this example:
2963 .code
2964 mysql_servers = <value not displayable>
2965 .endd
2966 If &%configure_file%& is given as an argument, the name of the run time
2967 configuration file is output.
2968 If a list of configuration files was supplied, the value that is output here
2969 is the name of the file that was actually used.
2971 .cindex "daemon" "process id (pid)"
2972 .cindex "pid (process id)" "of daemon"
2973 If &%log_file_path%& or &%pid_file_path%& are given, the names of the
2974 directories where log files and daemon pid files are written are output,
2975 respectively. If these values are unset, log files are written in a
2976 sub-directory of the spool directory called &%log%&, and the pid file is
2977 written directly into the spool directory.
2979 If &%-bP%& is followed by a name preceded by &`+`&, for example,
2980 .code
2981 exim -bP +local_domains
2982 .endd
2983 it searches for a matching named list of any type (domain, host, address, or
2984 local part) and outputs what it finds.
2986 .cindex "options" "router &-- extracting"
2987 .cindex "options" "transport &-- extracting"
2988 .cindex "options" "authenticator &-- extracting"
2989 If one of the words &%router%&, &%transport%&, or &%authenticator%& is given,
2990 followed by the name of an appropriate driver instance, the option settings for
2991 that driver are output. For example:
2992 .code
2993 exim -bP transport local_delivery
2994 .endd
2995 The generic driver options are output first, followed by the driver's private
2996 options. A list of the names of drivers of a particular type can be obtained by
2997 using one of the words &%router_list%&, &%transport_list%&, or
2998 &%authenticator_list%&, and a complete list of all drivers with their option
2999 settings can be obtained by using &%routers%&, &%transports%&, or
3000 &%authenticators%&.
3002 .cindex "options" "macro &-- extracting"
3003 If invoked by an admin user, then &%macro%&, &%macro_list%& and &%macros%&
3004 are available, similarly to the drivers. Because macros are sometimes used
3005 for storing passwords, this option is restricted.
3006 The output format is one item per line.
3008 .vitem &%-bp%&
3009 .oindex "&%-bp%&"
3010 .cindex "queue" "listing messages on"
3011 .cindex "listing" "messages on the queue"
3012 This option requests a listing of the contents of the mail queue on the
3013 standard output. If the &%-bp%& option is followed by a list of message ids,
3014 just those messages are listed. By default, this option can be used only by an
3015 admin user. However, the &%queue_list_requires_admin%& option can be set false
3016 to allow any user to see the queue.
3018 Each message on the queue is displayed as in the following example:
3019 .code
3020 25m 2.9K 0t5C6f-0000c8-00 <alice@wonderland.fict.example>
3021 red.king@looking-glass.fict.example
3022 <other addresses>
3023 .endd
3024 .cindex "message" "size in queue listing"
3025 .cindex "size" "of message"
3026 The first line contains the length of time the message has been on the queue
3027 (in this case 25 minutes), the size of the message (2.9K), the unique local
3028 identifier for the message, and the message sender, as contained in the
3029 envelope. For bounce messages, the sender address is empty, and appears as
3030 &"<>"&. If the message was submitted locally by an untrusted user who overrode
3031 the default sender address, the user's login name is shown in parentheses
3032 before the sender address.
3034 .cindex "frozen messages" "in queue listing"
3035 If the message is frozen (attempts to deliver it are suspended) then the text
3036 &"*** frozen ***"& is displayed at the end of this line.
3038 The recipients of the message (taken from the envelope, not the headers) are
3039 displayed on subsequent lines. Those addresses to which the message has already
3040 been delivered are marked with the letter D. If an original address gets
3041 expanded into several addresses via an alias or forward file, the original is
3042 displayed with a D only when deliveries for all of its child addresses are
3043 complete.
3046 .vitem &%-bpa%&
3047 .oindex "&%-bpa%&"
3048 This option operates like &%-bp%&, but in addition it shows delivered addresses
3049 that were generated from the original top level address(es) in each message by
3050 alias or forwarding operations. These addresses are flagged with &"+D"& instead
3051 of just &"D"&.
3054 .vitem &%-bpc%&
3055 .oindex "&%-bpc%&"
3056 .cindex "queue" "count of messages on"
3057 This option counts the number of messages on the queue, and writes the total
3058 to the standard output. It is restricted to admin users, unless
3059 &%queue_list_requires_admin%& is set false.
3062 .vitem &%-bpr%&
3063 .oindex "&%-bpr%&"
3064 This option operates like &%-bp%&, but the output is not sorted into
3065 chronological order of message arrival. This can speed it up when there are
3066 lots of messages on the queue, and is particularly useful if the output is
3067 going to be post-processed in a way that doesn't need the sorting.
3069 .vitem &%-bpra%&
3070 .oindex "&%-bpra%&"
3071 This option is a combination of &%-bpr%& and &%-bpa%&.
3073 .vitem &%-bpru%&
3074 .oindex "&%-bpru%&"
3075 This option is a combination of &%-bpr%& and &%-bpu%&.
3078 .vitem &%-bpu%&
3079 .oindex "&%-bpu%&"
3080 This option operates like &%-bp%& but shows only undelivered top-level
3081 addresses for each message displayed. Addresses generated by aliasing or
3082 forwarding are not shown, unless the message was deferred after processing by a
3083 router with the &%one_time%& option set.
3086 .vitem &%-brt%&
3087 .oindex "&%-brt%&"
3088 .cindex "testing" "retry configuration"
3089 .cindex "retry" "configuration testing"
3090 This option is for testing retry rules, and it must be followed by up to three
3091 arguments. It causes Exim to look for a retry rule that matches the values
3092 and to write it to the standard output. For example:
3093 .code
3094 exim -brt bach.comp.mus.example
3095 Retry rule: *.comp.mus.example F,2h,15m; F,4d,30m;
3096 .endd
3097 See chapter &<<CHAPretry>>& for a description of Exim's retry rules. The first
3098 argument, which is required, can be a complete address in the form
3099 &'local_part@domain'&, or it can be just a domain name. If the second argument
3100 contains a dot, it is interpreted as an optional second domain name; if no
3101 retry rule is found for the first argument, the second is tried. This ties in
3102 with Exim's behaviour when looking for retry rules for remote hosts &-- if no
3103 rule is found that matches the host, one that matches the mail domain is
3104 sought. Finally, an argument that is the name of a specific delivery error, as
3105 used in setting up retry rules, can be given. For example:
3106 .code
3107 exim -brt haydn.comp.mus.example quota_3d
3108 Retry rule: *@haydn.comp.mus.example quota_3d F,1h,15m
3109 .endd
3111 .vitem &%-brw%&
3112 .oindex "&%-brw%&"
3113 .cindex "testing" "rewriting"
3114 .cindex "rewriting" "testing"
3115 This option is for testing address rewriting rules, and it must be followed by
3116 a single argument, consisting of either a local part without a domain, or a
3117 complete address with a fully qualified domain. Exim outputs how this address
3118 would be rewritten for each possible place it might appear. See chapter
3119 &<<CHAPrewrite>>& for further details.
3121 .vitem &%-bS%&
3122 .oindex "&%-bS%&"
3123 .cindex "SMTP" "batched incoming"
3124 .cindex "batched SMTP input"
3125 This option is used for batched SMTP input, which is an alternative interface
3126 for non-interactive local message submission. A number of messages can be
3127 submitted in a single run. However, despite its name, this is not really SMTP
3128 input. Exim reads each message's envelope from SMTP commands on the standard
3129 input, but generates no responses. If the caller is trusted, or
3130 &%untrusted_set_sender%& is set, the senders in the SMTP MAIL commands are
3131 believed; otherwise the sender is always the caller of Exim.
3133 The message itself is read from the standard input, in SMTP format (leading
3134 dots doubled), terminated by a line containing just a single dot. An error is
3135 provoked if the terminating dot is missing. A further message may then follow.
3137 As for other local message submissions, the contents of incoming batch SMTP
3138 messages can be checked using the non-SMTP ACL (see chapter &<<CHAPACL>>&).
3139 Unqualified addresses are automatically qualified using &%qualify_domain%& and
3140 &%qualify_recipient%&, as appropriate, unless the &%-bnq%& option is used.
3142 Some other SMTP commands are recognized in the input. HELO and EHLO act
3143 as RSET; VRFY, EXPN, ETRN, and HELP act as NOOP;
3144 QUIT quits, ignoring the rest of the standard input.
3146 .cindex "return code" "for &%-bS%&"
3147 If any error is encountered, reports are written to the standard output and
3148 error streams, and Exim gives up immediately. The return code is 0 if no error
3149 was detected; it is 1 if one or more messages were accepted before the error
3150 was detected; otherwise it is 2.
3152 More details of input using batched SMTP are given in section
3153 &<<SECTincomingbatchedSMTP>>&.
3155 .vitem &%-bs%&
3156 .oindex "&%-bs%&"
3157 .cindex "SMTP" "local input"
3158 .cindex "local SMTP input"
3159 This option causes Exim to accept one or more messages by reading SMTP commands
3160 on the standard input, and producing SMTP replies on the standard output. SMTP
3161 policy controls, as defined in ACLs (see chapter &<<CHAPACL>>&) are applied.
3162 Some user agents use this interface as a way of passing locally-generated
3163 messages to the MTA.
3165 In
3166 .cindex "sender" "source of"
3167 this usage, if the caller of Exim is trusted, or &%untrusted_set_sender%& is
3168 set, the senders of messages are taken from the SMTP MAIL commands.
3169 Otherwise the content of these commands is ignored and the sender is set up as
3170 the calling user. Unqualified addresses are automatically qualified using
3171 &%qualify_domain%& and &%qualify_recipient%&, as appropriate, unless the
3172 &%-bnq%& option is used.
3174 .cindex "inetd"
3175 The
3176 &%-bs%& option is also used to run Exim from &'inetd'&, as an alternative to
3177 using a listening daemon. Exim can distinguish the two cases by checking
3178 whether the standard input is a TCP/IP socket. When Exim is called from
3179 &'inetd'&, the source of the mail is assumed to be remote, and the comments
3180 above concerning senders and qualification do not apply. In this situation,
3181 Exim behaves in exactly the same way as it does when receiving a message via
3182 the listening daemon.
3184 .new
3185 .vitem &%-bmalware%&&~<&'filename'&>
3186 .oindex "&%-bmalware%&"
3187 .cindex "testing", "malware"
3188 .cindex "malware scan test"
3189 This debugging option causes Exim to scan the given file,
3190 using the malware scanning framework. The option of &%av_scanner%& influences
3191 this option, so if &%av_scanner%&'s value is dependent upon an expansion then
3192 the expansion should have defaults which apply to this invocation. ACLs are
3193 not invoked, so if &%av_scanner%& references an ACL variable then that variable
3194 will never be populated and &%-bmalware%& will fail.
3196 Exim will have changed working directory before resolving the filename, so
3197 using fully qualified pathnames is advisable. Exim will be running as the Exim
3198 user when it tries to open the file, rather than as the invoking user.
3199 This option requires admin privileges.
3201 The &%-bmalware%& option will not be extended to be more generally useful,
3202 there are better tools for file-scanning. This option exists to help
3203 administrators verify their Exim and AV scanner configuration.
3204 .wen
3206 .vitem &%-bt%&
3207 .oindex "&%-bt%&"
3208 .cindex "testing" "addresses"
3209 .cindex "address" "testing"
3210 This option runs Exim in address testing mode, in which each argument is taken
3211 as a recipient address to be tested for deliverability. The results are
3212 written to the standard output. If a test fails, and the caller is not an admin
3213 user, no details of the failure are output, because these might contain
3214 sensitive information such as usernames and passwords for database lookups.
3216 If no arguments are given, Exim runs in an interactive manner, prompting with a
3217 right angle bracket for addresses to be tested.
3219 Unlike the &%-be%& test option, you cannot arrange for Exim to use the
3220 &[readline()]& function, because it is running as &'root'& and there are
3221 security issues.
3223 Each address is handled as if it were the recipient address of a message
3224 (compare the &%-bv%& option). It is passed to the routers and the result is
3225 written to the standard output. However, any router that has
3226 &%no_address_test%& set is bypassed. This can make &%-bt%& easier to use for
3227 genuine routing tests if your first router passes everything to a scanner
3228 program.
3230 .cindex "return code" "for &%-bt%&"
3231 The return code is 2 if any address failed outright; it is 1 if no address
3232 failed outright but at least one could not be resolved for some reason. Return
3233 code 0 is given only when all addresses succeed.
3235 .cindex "duplicate addresses"
3236 &*Note*&: When actually delivering a message, Exim removes duplicate recipient
3237 addresses after routing is complete, so that only one delivery takes place.
3238 This does not happen when testing with &%-bt%&; the full results of routing are
3239 always shown.
3241 &*Warning*&: &%-bt%& can only do relatively simple testing. If any of the
3242 routers in the configuration makes any tests on the sender address of a
3243 message,
3244 .oindex "&%-f%&" "for address testing"
3245 you can use the &%-f%& option to set an appropriate sender when running
3246 &%-bt%& tests. Without it, the sender is assumed to be the calling user at the
3247 default qualifying domain. However, if you have set up (for example) routers
3248 whose behaviour depends on the contents of an incoming message, you cannot test
3249 those conditions using &%-bt%&. The &%-N%& option provides a possible way of
3250 doing such tests.
3252 .vitem &%-bV%&
3253 .oindex "&%-bV%&"
3254 .cindex "version number of Exim"
3255 This option causes Exim to write the current version number, compilation
3256 number, and compilation date of the &'exim'& binary to the standard output.
3257 It also lists the DBM library that is being used, the optional modules (such as
3258 specific lookup types), the drivers that are included in the binary, and the
3259 name of the run time configuration file that is in use.
3261 As part of its operation, &%-bV%& causes Exim to read and syntax check its
3262 configuration file. However, this is a static check only. It cannot check
3263 values that are to be expanded. For example, although a misspelt ACL verb is
3264 detected, an error in the verb's arguments is not. You cannot rely on &%-bV%&
3265 alone to discover (for example) all the typos in the configuration; some
3266 realistic testing is needed. The &%-bh%& and &%-N%& options provide more
3267 dynamic testing facilities.
3269 .vitem &%-bv%&
3270 .oindex "&%-bv%&"
3271 .cindex "verifying address" "using &%-bv%&"
3272 .cindex "address" "verification"
3273 This option runs Exim in address verification mode, in which each argument is
3274 taken as a recipient address to be verified by the routers. (This does
3275 not involve any verification callouts). During normal operation, verification
3276 happens mostly as a consequence processing a &%verify%& condition in an ACL
3277 (see chapter &<<CHAPACL>>&). If you want to test an entire ACL, possibly
3278 including callouts, see the &%-bh%& and &%-bhc%& options.
3280 If verification fails, and the caller is not an admin user, no details of the
3281 failure are output, because these might contain sensitive information such as
3282 usernames and passwords for database lookups.
3284 If no arguments are given, Exim runs in an interactive manner, prompting with a
3285 right angle bracket for addresses to be verified.
3287 Unlike the &%-be%& test option, you cannot arrange for Exim to use the
3288 &[readline()]& function, because it is running as &'exim'& and there are
3289 security issues.
3291 Verification differs from address testing (the &%-bt%& option) in that routers
3292 that have &%no_verify%& set are skipped, and if the address is accepted by a
3293 router that has &%fail_verify%& set, verification fails. The address is
3294 verified as a recipient if &%-bv%& is used; to test verification for a sender
3295 address, &%-bvs%& should be used.
3297 If the &%-v%& option is not set, the output consists of a single line for each
3298 address, stating whether it was verified or not, and giving a reason in the
3299 latter case. Without &%-v%&, generating more than one address by redirection
3300 causes verification to end successfully, without considering the generated
3301 addresses. However, if just one address is generated, processing continues,
3302 and the generated address must verify successfully for the overall verification
3303 to succeed.
3305 When &%-v%& is set, more details are given of how the address has been handled,
3306 and in the case of address redirection, all the generated addresses are also
3307 considered. Verification may succeed for some and fail for others.
3309 The
3310 .cindex "return code" "for &%-bv%&"
3311 return code is 2 if any address failed outright; it is 1 if no address
3312 failed outright but at least one could not be resolved for some reason. Return
3313 code 0 is given only when all addresses succeed.
3315 If any of the routers in the configuration makes any tests on the sender
3316 address of a message, you should use the &%-f%& option to set an appropriate
3317 sender when running &%-bv%& tests. Without it, the sender is assumed to be the
3318 calling user at the default qualifying domain.
3320 .vitem &%-bvs%&
3321 .oindex "&%-bvs%&"
3322 This option acts like &%-bv%&, but verifies the address as a sender rather
3323 than a recipient address. This affects any rewriting and qualification that
3324 might happen.
3326 .new
3327 .vitem &%-C%&&~<&'filelist'&>
3328 .oindex "&%-C%&"
3329 .cindex "configuration file" "alternate"
3330 .cindex "CONFIGURE_FILE"
3331 .cindex "alternate configuration file"
3332 This option causes Exim to find the run time configuration file from the given
3333 list instead of from the list specified by the CONFIGURE_FILE
3334 compile-time setting. Usually, the list will consist of just a single file
3335 name, but it can be a colon-separated list of names. In this case, the first
3336 file that exists is used. Failure to open an existing file stops Exim from
3337 proceeding any further along the list, and an error is generated.
3339 When this option is used by a caller other than root, and the list is different
3340 from the compiled-in list, Exim gives up its root privilege immediately, and
3341 runs with the real and effective uid and gid set to those of the caller.
3342 However, if a TRUSTED_CONFIG_LIST file is defined in &_Local/Makefile_&, that
3343 file contains a list of full pathnames, one per line, for configuration files
3344 which are trusted. Root privilege is retained for any configuration file so
3345 listed, as long as the caller is the Exim user (or the user specified in the
3346 CONFIGURE_OWNER option, if any), and as long as the configuration file is
3347 not writeable by inappropriate users or groups.
3349 Leaving TRUSTED_CONFIG_LIST unset precludes the possibility of testing a
3350 configuration using &%-C%& right through message reception and delivery,
3351 even if the caller is root. The reception works, but by that time, Exim is
3352 running as the Exim user, so when it re-executes to regain privilege for the
3353 delivery, the use of &%-C%& causes privilege to be lost. However, root can
3354 test reception and delivery using two separate commands (one to put a message
3355 on the queue, using &%-odq%&, and another to do the delivery, using &%-M%&).
3357 If ALT_CONFIG_PREFIX is defined &_in Local/Makefile_&, it specifies a
3358 prefix string with which any file named in a &%-C%& command line option
3359 must start. In addition, the file name must not contain the sequence &`/../`&.
3360 However, if the value of the &%-C%& option is identical to the value of
3361 CONFIGURE_FILE in &_Local/Makefile_&, Exim ignores &%-C%& and proceeds as
3362 usual. There is no default setting for ALT_CONFIG_PREFIX; when it is
3363 unset, any file name can be used with &%-C%&.
3365 ALT_CONFIG_PREFIX can be used to confine alternative configuration files
3366 to a directory to which only root has access. This prevents someone who has
3367 broken into the Exim account from running a privileged Exim with an arbitrary
3368 configuration file.
3370 The &%-C%& facility is useful for ensuring that configuration files are
3371 syntactically correct, but cannot be used for test deliveries, unless the
3372 caller is privileged, or unless it is an exotic configuration that does not
3373 require privilege. No check is made on the owner or group of the files
3374 specified by this option.
3375 .wen
3377 .new
3378 .vitem &%-D%&<&'macro'&>=<&'value'&>
3379 .oindex "&%-D%&"
3380 .cindex "macro" "setting on command line"
3381 This option can be used to override macro definitions in the configuration file
3382 (see section &<<SECTmacrodefs>>&). However, like &%-C%&, if it is used by an
3383 unprivileged caller, it causes Exim to give up its root privilege.
3384 If DISABLE_D_OPTION is defined in &_Local/Makefile_&, the use of &%-D%& is
3385 completely disabled, and its use causes an immediate error exit.
3387 If WHITELIST_D_MACROS is defined in &_Local/Makefile_& then it should be a
3388 colon-separated list of macros which are considered safe and, if &%-D%& only
3389 supplies macros from this list, and the values are acceptable, then Exim will
3390 not give up root privilege if the caller is root, the Exim run-time user, or
3391 the CONFIGURE_OWNER, if set. This is a transition mechanism and is expected
3392 to be removed in the future. Acceptable values for the macros satisfy the
3393 regexp: &`^[A-Za-z0-9_/.-]*$`&
3395 The entire option (including equals sign if present) must all be within one
3396 command line item. &%-D%& can be used to set the value of a macro to the empty
3397 string, in which case the equals sign is optional. These two commands are
3398 synonymous:
3399 .code
3400 exim -DABC ...
3401 exim -DABC= ...
3402 .endd
3403 To include spaces in a macro definition item, quotes must be used. If you use
3404 quotes, spaces are permitted around the macro name and the equals sign. For
3405 example:
3406 .code
3407 exim '-D ABC = something' ...
3408 .endd
3409 &%-D%& may be repeated up to 10 times on a command line.
3410 .wen
3412 .vitem &%-d%&<&'debug&~options'&>
3413 .oindex "&%-d%&"
3414 .cindex "debugging" "list of selectors"
3415 .cindex "debugging" "&%-d%& option"
3416 This option causes debugging information to be written to the standard
3417 error stream. It is restricted to admin users because debugging output may show
3418 database queries that contain password information. Also, the details of users'
3419 filter files should be protected. If a non-admin user uses &%-d%&, Exim
3420 writes an error message to the standard error stream and exits with a non-zero
3421 return code.
3423 When &%-d%& is used, &%-v%& is assumed. If &%-d%& is given on its own, a lot of
3424 standard debugging data is output. This can be reduced, or increased to include
3425 some more rarely needed information, by directly following &%-d%& with a string
3426 made up of names preceded by plus or minus characters. These add or remove sets
3427 of debugging data, respectively. For example, &%-d+filter%& adds filter
3428 debugging, whereas &%-d-all+filter%& selects only filter debugging. Note that
3429 no spaces are allowed in the debug setting. The available debugging categories
3430 are:
3431 .display
3432 &`acl `& ACL interpretation
3433 &`auth `& authenticators
3434 &`deliver `& general delivery logic
3435 &`dns `& DNS lookups (see also resolver)
3436 &`dnsbl `& DNS black list (aka RBL) code
3437 &`exec `& arguments for &[execv()]& calls
3438 &`expand `& detailed debugging for string expansions
3439 &`filter `& filter handling
3440 &`hints_lookup `& hints data lookups
3441 &`host_lookup `& all types of name-to-IP address handling
3442 &`ident `& ident lookup
3443 &`interface `& lists of local interfaces
3444 &`lists `& matching things in lists
3445 &`load `& system load checks
3446 &`local_scan `& can be used by &[local_scan()]& (see chapter &&&
3447 &<<CHAPlocalscan>>&)
3448 &`lookup `& general lookup code and all lookups
3449 &`memory `& memory handling
3450 &`pid `& add pid to debug output lines
3451 &`process_info `& setting info for the process log
3452 &`queue_run `& queue runs
3453 &`receive `& general message reception logic
3454 &`resolver `& turn on the DNS resolver's debugging output
3455 &`retry `& retry handling
3456 &`rewrite `& address rewriting
3457 &`route `& address routing
3458 &`timestamp `& add timestamp to debug output lines
3459 &`tls `& TLS logic
3460 &`transport `& transports
3461 &`uid `& changes of uid/gid and looking up uid/gid
3462 &`verify `& address verification logic
3463 &`all `& almost all of the above (see below), and also &%-v%&
3464 .endd
3465 The &`all`& option excludes &`memory`& when used as &`+all`&, but includes it
3466 for &`-all`&. The reason for this is that &`+all`& is something that people
3467 tend to use when generating debug output for Exim maintainers. If &`+memory`&
3468 is included, an awful lot of output that is very rarely of interest is
3469 generated, so it now has to be explicitly requested. However, &`-all`& does
3470 turn everything off.
3472 .cindex "resolver, debugging output"
3473 .cindex "DNS resolver, debugging output"
3474 The &`resolver`& option produces output only if the DNS resolver was compiled
3475 with DEBUG enabled. This is not the case in some operating systems. Also,
3476 unfortunately, debugging output from the DNS resolver is written to stdout
3477 rather than stderr.
3479 The default (&%-d%& with no argument) omits &`expand`&, &`filter`&,
3480 &`interface`&, &`load`&, &`memory`&, &`pid`&, &`resolver`&, and &`timestamp`&.
3481 However, the &`pid`& selector is forced when debugging is turned on for a
3482 daemon, which then passes it on to any re-executed Exims. Exim also
3483 automatically adds the pid to debug lines when several remote deliveries are
3484 run in parallel.
3486 The &`timestamp`& selector causes the current time to be inserted at the start
3487 of all debug output lines. This can be useful when trying to track down delays
3488 in processing.
3490 If the &%debug_print%& option is set in any driver, it produces output whenever
3491 any debugging is selected, or if &%-v%& is used.
3493 .vitem &%-dd%&<&'debug&~options'&>
3494 .oindex "&%-dd%&"
3495 This option behaves exactly like &%-d%& except when used on a command that
3496 starts a daemon process. In that case, debugging is turned off for the
3497 subprocesses that the daemon creates. Thus, it is useful for monitoring the
3498 behaviour of the daemon without creating as much output as full debugging does.
3500 .vitem &%-dropcr%&
3501 .oindex "&%-dropcr%&"
3502 This is an obsolete option that is now a no-op. It used to affect the way Exim
3503 handled CR and LF characters in incoming messages. What happens now is
3504 described in section &<<SECTlineendings>>&.
3506 .vitem &%-E%&
3507 .oindex "&%-E%&"
3508 .cindex "bounce message" "generating"
3509 This option specifies that an incoming message is a locally-generated delivery
3510 failure report. It is used internally by Exim when handling delivery failures
3511 and is not intended for external use. Its only effect is to stop Exim
3512 generating certain messages to the postmaster, as otherwise message cascades
3513 could occur in some situations. As part of the same option, a message id may
3514 follow the characters &%-E%&. If it does, the log entry for the receipt of the
3515 new message contains the id, following &"R="&, as a cross-reference.
3517 .vitem &%-e%&&'x'&
3518 .oindex "&%-e%&&'x'&"
3519 There are a number of Sendmail options starting with &%-oe%& which seem to be
3520 called by various programs without the leading &%o%& in the option. For
3521 example, the &%vacation%& program uses &%-eq%&. Exim treats all options of the
3522 form &%-e%&&'x'& as synonymous with the corresponding &%-oe%&&'x'& options.
3524 .vitem &%-F%&&~<&'string'&>
3525 .oindex "&%-F%&"
3526 .cindex "sender" "name"
3527 .cindex "name" "of sender"
3528 This option sets the sender's full name for use when a locally-generated
3529 message is being accepted. In the absence of this option, the user's &'gecos'&
3530 entry from the password data is used. As users are generally permitted to alter
3531 their &'gecos'& entries, no security considerations are involved. White space
3532 between &%-F%& and the <&'string'&> is optional.
3534 .vitem &%-f%&&~<&'address'&>
3535 .oindex "&%-f%&"
3536 .cindex "sender" "address"
3537 .cindex "address" "sender"
3538 .cindex "trusted users"
3539 .cindex "envelope sender"
3540 .cindex "user" "trusted"
3541 This option sets the address of the envelope sender of a locally-generated
3542 message (also known as the return path). The option can normally be used only
3543 by a trusted user, but &%untrusted_set_sender%& can be set to allow untrusted
3544 users to use it.
3546 Processes running as root or the Exim user are always trusted. Other
3547 trusted users are defined by the &%trusted_users%& or &%trusted_groups%&
3548 options. In the absence of &%-f%&, or if the caller is not trusted, the sender
3549 of a local message is set to the caller's login name at the default qualify
3550 domain.
3552 There is one exception to the restriction on the use of &%-f%&: an empty sender
3553 can be specified by any user, trusted or not, to create a message that can
3554 never provoke a bounce. An empty sender can be specified either as an empty
3555 string, or as a pair of angle brackets with nothing between them, as in these
3556 examples of shell commands:
3557 .code
3558 exim -f '<>' user@domain
3559 exim -f "" user@domain
3560 .endd
3561 In addition, the use of &%-f%& is not restricted when testing a filter file
3562 with &%-bf%& or when testing or verifying addresses using the &%-bt%& or
3563 &%-bv%& options.
3565 Allowing untrusted users to change the sender address does not of itself make
3566 it possible to send anonymous mail. Exim still checks that the &'From:'& header
3567 refers to the local user, and if it does not, it adds a &'Sender:'& header,
3568 though this can be overridden by setting &%no_local_from_check%&.
3570 White
3571 .cindex "&""From""& line"
3572 space between &%-f%& and the <&'address'&> is optional (that is, they can be
3573 given as two arguments or one combined argument). The sender of a
3574 locally-generated message can also be set (when permitted) by an initial
3575 &"From&~"& line in the message &-- see the description of &%-bm%& above &-- but
3576 if &%-f%& is also present, it overrides &"From&~"&.
3578 .vitem &%-G%&
3579 .oindex "&%-G%&"
3580 .cindex "Sendmail compatibility" "&%-G%& option ignored"
3581 This is a Sendmail option which is ignored by Exim.
3583 .vitem &%-h%&&~<&'number'&>
3584 .oindex "&%-h%&"
3585 .cindex "Sendmail compatibility" "&%-h%& option ignored"
3586 This option is accepted for compatibility with Sendmail, but has no effect. (In
3587 Sendmail it overrides the &"hop count"& obtained by counting &'Received:'&
3588 headers.)
3590 .vitem &%-i%&
3591 .oindex "&%-i%&"
3592 .cindex "Solaris" "&'mail'& command"
3593 .cindex "dot" "in incoming non-SMTP message"
3594 This option, which has the same effect as &%-oi%&, specifies that a dot on a
3595 line by itself should not terminate an incoming, non-SMTP message. I can find
3596 no documentation for this option in Solaris 2.4 Sendmail, but the &'mailx'&
3597 command in Solaris 2.4 uses it. See also &%-ti%&.
3599 .vitem &%-M%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3600 .oindex "&%-M%&"
3601 .cindex "forcing delivery"
3602 .cindex "delivery" "forcing attempt"
3603 .cindex "frozen messages" "forcing delivery"
3604 This option requests Exim to run a delivery attempt on each message in turn. If
3605 any of the messages are frozen, they are automatically thawed before the
3606 delivery attempt. The settings of &%queue_domains%&, &%queue_smtp_domains%&,
3607 and &%hold_domains%& are ignored.
3609 Retry
3610 .cindex "hints database" "overriding retry hints"
3611 hints for any of the addresses are overridden &-- Exim tries to deliver even if
3612 the normal retry time has not yet been reached. This option requires the caller
3613 to be an admin user. However, there is an option called &%prod_requires_admin%&
3614 which can be set false to relax this restriction (and also the same requirement
3615 for the &%-q%&, &%-R%&, and &%-S%& options).
3617 The deliveries happen synchronously, that is, the original Exim process does
3618 not terminate until all the delivery attempts have finished. No output is
3619 produced unless there is a serious error. If you want to see what is happening,
3620 use the &%-v%& option as well, or inspect Exim's main log.
3622 .vitem &%-Mar%&&~<&'message&~id'&>&~<&'address'&>&~<&'address'&>&~...
3623 .oindex "&%-Mar%&"
3624 .cindex "message" "adding recipients"
3625 .cindex "recipient" "adding"
3626 This option requests Exim to add the addresses to the list of recipients of the
3627 message (&"ar"& for &"add recipients"&). The first argument must be a message
3628 id, and the remaining ones must be email addresses. However, if the message is
3629 active (in the middle of a delivery attempt), it is not altered. This option
3630 can be used only by an admin user.
3632 .vitem "&%-MC%&&~<&'transport'&>&~<&'hostname'&>&~<&'sequence&~number'&>&&&
3633 &~<&'message&~id'&>"
3634 .oindex "&%-MC%&"
3635 .cindex "SMTP" "passed connection"
3636 .cindex "SMTP" "multiple deliveries"
3637 .cindex "multiple SMTP deliveries"
3638 This option is not intended for use by external callers. It is used internally
3639 by Exim to invoke another instance of itself to deliver a waiting message using
3640 an existing SMTP connection, which is passed as the standard input. Details are
3641 given in chapter &<<CHAPSMTP>>&. This must be the final option, and the caller
3642 must be root or the Exim user in order to use it.
3644 .vitem &%-MCA%&
3645 .oindex "&%-MCA%&"
3646 This option is not intended for use by external callers. It is used internally
3647 by Exim in conjunction with the &%-MC%& option. It signifies that the
3648 connection to the remote host has been authenticated.
3650 .vitem &%-MCP%&
3651 .oindex "&%-MCP%&"
3652 This option is not intended for use by external callers. It is used internally
3653 by Exim in conjunction with the &%-MC%& option. It signifies that the server to
3654 which Exim is connected supports pipelining.
3656 .vitem &%-MCQ%&&~<&'process&~id'&>&~<&'pipe&~fd'&>
3657 .oindex "&%-MCQ%&"
3658 This option is not intended for use by external callers. It is used internally
3659 by Exim in conjunction with the &%-MC%& option when the original delivery was
3660 started by a queue runner. It passes on the process id of the queue runner,
3661 together with the file descriptor number of an open pipe. Closure of the pipe
3662 signals the final completion of the sequence of processes that are passing
3663 messages through the same SMTP connection.
3665 .vitem &%-MCS%&
3666 .oindex "&%-MCS%&"
3667 This option is not intended for use by external callers. It is used internally
3668 by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
3669 SMTP SIZE option should be used on messages delivered down the existing
3670 connection.
3672 .vitem &%-MCT%&
3673 .oindex "&%-MCT%&"
3674 This option is not intended for use by external callers. It is used internally
3675 by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
3676 host to which Exim is connected supports TLS encryption.
3678 .vitem &%-Mc%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3679 .oindex "&%-Mc%&"
3680 .cindex "hints database" "not overridden by &%-Mc%&"
3681 .cindex "delivery" "manually started &-- not forced"
3682 This option requests Exim to run a delivery attempt on each message in turn,
3683 but unlike the &%-M%& option, it does check for retry hints, and respects any
3684 that are found. This option is not very useful to external callers. It is
3685 provided mainly for internal use by Exim when it needs to re-invoke itself in
3686 order to regain root privilege for a delivery (see chapter &<<CHAPsecurity>>&).
3687 However, &%-Mc%& can be useful when testing, in order to run a delivery that
3688 respects retry times and other options such as &%hold_domains%& that are
3689 overridden when &%-M%& is used. Such a delivery does not count as a queue run.
3690 If you want to run a specific delivery as if in a queue run, you should use
3691 &%-q%& with a message id argument. A distinction between queue run deliveries
3692 and other deliveries is made in one or two places.
3694 .vitem &%-Mes%&&~<&'message&~id'&>&~<&'address'&>
3695 .oindex "&%-Mes%&"
3696 .cindex "message" "changing sender"
3697 .cindex "sender" "changing"
3698 This option requests Exim to change the sender address in the message to the
3699 given address, which must be a fully qualified address or &"<>"& (&"es"& for
3700 &"edit sender"&). There must be exactly two arguments. The first argument must
3701 be a message id, and the second one an email address. However, if the message
3702 is active (in the middle of a delivery attempt), its status is not altered.
3703 This option can be used only by an admin user.
3705 .vitem &%-Mf%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3706 .oindex "&%-Mf%&"
3707 .cindex "freezing messages"
3708 .cindex "message" "manually freezing"
3709 This option requests Exim to mark each listed message as &"frozen"&. This
3710 prevents any delivery attempts taking place until the message is &"thawed"&,
3711 either manually or as a result of the &%auto_thaw%& configuration option.
3712 However, if any of the messages are active (in the middle of a delivery
3713 attempt), their status is not altered. This option can be used only by an admin
3714 user.
3716 .vitem &%-Mg%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3717 .oindex "&%-Mg%&"
3718 .cindex "giving up on messages"
3719 .cindex "message" "abandoning delivery attempts"
3720 .cindex "delivery" "abandoning further attempts"
3721 This option requests Exim to give up trying to deliver the listed messages,
3722 including any that are frozen. However, if any of the messages are active,
3723 their status is not altered. For non-bounce messages, a delivery error message
3724 is sent to the sender, containing the text &"cancelled by administrator"&.
3725 Bounce messages are just discarded. This option can be used only by an admin
3726 user.
3728 .vitem &%-Mmad%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3729 .oindex "&%-Mmad%&"
3730 .cindex "delivery" "cancelling all"
3731 This option requests Exim to mark all the recipient addresses in the messages
3732 as already delivered (&"mad"& for &"mark all delivered"&). However, if any
3733 message is active (in the middle of a delivery attempt), its status is not
3734 altered. This option can be used only by an admin user.
3736 .vitem &%-Mmd%&&~<&'message&~id'&>&~<&'address'&>&~<&'address'&>&~...
3737 .oindex "&%-Mmd%&"
3738 .cindex "delivery" "cancelling by address"
3739 .cindex "recipient" "removing"
3740 .cindex "removing recipients"
3741 This option requests Exim to mark the given addresses as already delivered
3742 (&"md"& for &"mark delivered"&). The first argument must be a message id, and
3743 the remaining ones must be email addresses. These are matched to recipient
3744 addresses in the message in a case-sensitive manner. If the message is active
3745 (in the middle of a delivery attempt), its status is not altered. This option
3746 can be used only by an admin user.
3748 .vitem &%-Mrm%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3749 .oindex "&%-Mrm%&"
3750 .cindex "removing messages"
3751 .cindex "abandoning mail"
3752 .cindex "message" "manually discarding"
3753 This option requests Exim to remove the given messages from the queue. No
3754 bounce messages are sent; each message is simply forgotten. However, if any of
3755 the messages are active, their status is not altered. This option can be used
3756 only by an admin user or by the user who originally caused the message to be
3757 placed on the queue.
3759 .vitem &%-Mset%&&~<&'message&~id'&>
3760 .oindex "&%-Mset%&
3761 .cindex "testing" "string expansion"
3762 .cindex "expansion" "testing"
3763 This option is useful only in conjunction with &%-be%& (that is, when testing
3764 string expansions). Exim loads the given message from its spool before doing
3765 the test expansions, thus setting message-specific variables such as
3766 &$message_size$& and the header variables. The &$recipients$& variable is made
3767 available. This feature is provided to make it easier to test expansions that
3768 make use of these variables. However, this option can be used only by an admin
3769 user. See also &%-bem%&.
3771 .vitem &%-Mt%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3772 .oindex "&%-Mt%&"
3773 .cindex "thawing messages"
3774 .cindex "unfreezing messages"
3775 .cindex "frozen messages" "thawing"
3776 .cindex "message" "thawing frozen"
3777 This option requests Exim to &"thaw"& any of the listed messages that are
3778 &"frozen"&, so that delivery attempts can resume. However, if any of the
3779 messages are active, their status is not altered. This option can be used only
3780 by an admin user.
3782 .vitem &%-Mvb%&&~<&'message&~id'&>
3783 .oindex "&%-Mvb%&"
3784 .cindex "listing" "message body"
3785 .cindex "message" "listing body of"
3786 This option causes the contents of the message body (-D) spool file to be
3787 written to the standard output. This option can be used only by an admin user.
3789 .vitem &%-Mvc%&&~<&'message&~id'&>
3790 .oindex "&%-Mvc%&"
3791 .cindex "message" "listing in RFC 2822 format"
3792 .cindex "listing" "message in RFC 2822 format"
3793 This option causes a copy of the complete message (header lines plus body) to
3794 be written to the standard output in RFC 2822 format. This option can be used
3795 only by an admin user.
3797 .vitem &%-Mvh%&&~<&'message&~id'&>
3798 .oindex "&%-Mvh%&"
3799 .cindex "listing" "message headers"
3800 .cindex "header lines" "listing"
3801 .cindex "message" "listing header lines"
3802 This option causes the contents of the message headers (-H) spool file to be
3803 written to the standard output. This option can be used only by an admin user.
3805 .vitem &%-Mvl%&&~<&'message&~id'&>
3806 .oindex "&%-Mvl%&"
3807 .cindex "listing" "message log"
3808 .cindex "message" "listing message log"
3809 This option causes the contents of the message log spool file to be written to
3810 the standard output. This option can be used only by an admin user.
3812 .vitem &%-m%&
3813 .oindex "&%-m%&"
3814 This is apparently a synonym for &%-om%& that is accepted by Sendmail, so Exim
3815 treats it that way too.
3817 .vitem &%-N%&
3818 .oindex "&%-N%&"
3819 .cindex "debugging" "&%-N%& option"
3820 .cindex "debugging" "suppressing delivery"
3821 This is a debugging option that inhibits delivery of a message at the transport
3822 level. It implies &%-v%&. Exim goes through many of the motions of delivery &--
3823 it just doesn't actually transport the message, but instead behaves as if it
3824 had successfully done so. However, it does not make any updates to the retry
3825 database, and the log entries for deliveries are flagged with &"*>"& rather
3826 than &"=>"&.
3828 Because &%-N%& discards any message to which it applies, only root or the Exim
3829 user are allowed to use it with &%-bd%&, &%-q%&, &%-R%& or &%-M%&. In other
3830 words, an ordinary user can use it only when supplying an incoming message to
3831 which it will apply. Although transportation never fails when &%-N%& is set, an
3832 address may be deferred because of a configuration problem on a transport, or a
3833 routing problem. Once &%-N%& has been used for a delivery attempt, it sticks to
3834 the message, and applies to any subsequent delivery attempts that may happen
3835 for that message.
3837 .vitem &%-n%&
3838 .oindex "&%-n%&"
3839 .cindex "Sendmail compatibility" "&%-n%& option ignored"
3840 This option is interpreted by Sendmail to mean &"no aliasing"&. It is ignored
3841 by Exim.
3843 .vitem &%-O%&&~<&'data'&>
3844 .oindex "&%-O%&"
3845 This option is interpreted by Sendmail to mean &`set option`&. It is ignored by
3846 Exim.
3848 .vitem &%-oA%&&~<&'file&~name'&>
3849 .oindex "&%-oA%&"
3850 .cindex "Sendmail compatibility" "&%-oA%& option"
3851 This option is used by Sendmail in conjunction with &%-bi%& to specify an
3852 alternative alias file name. Exim handles &%-bi%& differently; see the
3853 description above.
3855 .vitem &%-oB%&&~<&'n'&>
3856 .oindex "&%-oB%&"
3857 .cindex "SMTP" "passed connection"
3858 .cindex "SMTP" "multiple deliveries"
3859 .cindex "multiple SMTP deliveries"
3860 This is a debugging option which limits the maximum number of messages that can
3861 be delivered down one SMTP connection, overriding the value set in any &(smtp)&
3862 transport. If <&'n'&> is omitted, the limit is set to 1.
3864 .vitem &%-odb%&
3865 .oindex "&%-odb%&"
3866 .cindex "background delivery"
3867 .cindex "delivery" "in the background"
3868 This option applies to all modes in which Exim accepts incoming messages,
3869 including the listening daemon. It requests &"background"& delivery of such
3870 messages, which means that the accepting process automatically starts a
3871 delivery process for each message received, but does not wait for the delivery
3872 processes to finish.
3874 When all the messages have been received, the reception process exits,
3875 leaving the delivery processes to finish in their own time. The standard output
3876 and error streams are closed at the start of each delivery process.
3877 This is the default action if none of the &%-od%& options are present.
3879 If one of the queueing options in the configuration file
3880 (&%queue_only%& or &%queue_only_file%&, for example) is in effect, &%-odb%&
3881 overrides it if &%queue_only_override%& is set true, which is the default
3882 setting. If &%queue_only_override%& is set false, &%-odb%& has no effect.
3884 .vitem &%-odf%&
3885 .oindex "&%-odf%&"
3886 .cindex "foreground delivery"
3887 .cindex "delivery" "in the foreground"
3888 This option requests &"foreground"& (synchronous) delivery when Exim has
3889 accepted a locally-generated message. (For the daemon it is exactly the same as
3890 &%-odb%&.) A delivery process is automatically started to deliver the message,
3891 and Exim waits for it to complete before proceeding.
3893 The original Exim reception process does not finish until the delivery
3894 process for the final message has ended. The standard error stream is left open
3895 during deliveries.
3897 However, like &%-odb%&, this option has no effect if &%queue_only_override%& is
3898 false and one of the queueing options in the configuration file is in effect.
3900 If there is a temporary delivery error during foreground delivery, the
3901 message is left on the queue for later delivery, and the original reception
3902 process exits. See chapter &<<CHAPnonqueueing>>& for a way of setting up a
3903 restricted configuration that never queues messages.
3906 .vitem &%-odi%&
3907 .oindex "&%-odi%&"
3908 This option is synonymous with &%-odf%&. It is provided for compatibility with
3909 Sendmail.
3911 .vitem &%-odq%&
3912 .oindex "&%-odq%&"
3913 .cindex "non-immediate delivery"
3914 .cindex "delivery" "suppressing immediate"
3915 .cindex "queueing incoming messages"
3916 This option applies to all modes in which Exim accepts incoming messages,
3917 including the listening daemon. It specifies that the accepting process should
3918 not automatically start a delivery process for each message received. Messages
3919 are placed on the queue, and remain there until a subsequent queue runner
3920 process encounters them. There are several configuration options (such as
3921 &%queue_only%&) that can be used to queue incoming messages under certain
3922 conditions. This option overrides all of them and also &%-odqs%&. It always
3923 forces queueing.
3925 .vitem &%-odqs%&
3926 .oindex "&%-odqs%&"
3927 .cindex "SMTP" "delaying delivery"
3928 This option is a hybrid between &%-odb%&/&%-odi%& and &%-odq%&.
3929 However, like &%-odb%& and &%-odi%&, this option has no effect if
3930 &%queue_only_override%& is false and one of the queueing options in the
3931 configuration file is in effect.
3933 When &%-odqs%& does operate, a delivery process is started for each incoming
3934 message, in the background by default, but in the foreground if &%-odi%& is
3935 also present. The recipient addresses are routed, and local deliveries are done
3936 in the normal way. However, if any SMTP deliveries are required, they are not
3937 done at this time, so the message remains on the queue until a subsequent queue
3938 runner process encounters it. Because routing was done, Exim knows which
3939 messages are waiting for which hosts, and so a number of messages for the same
3940 host can be sent in a single SMTP connection. The &%queue_smtp_domains%&
3941 configuration option has the same effect for specific domains. See also the
3942 &%-qq%& option.
3944 .vitem &%-oee%&
3945 .oindex "&%-oee%&"
3946 .cindex "error" "reporting"
3947 If an error is detected while a non-SMTP message is being received (for
3948 example, a malformed address), the error is reported to the sender in a mail
3949 message.
3951 .cindex "return code" "for &%-oee%&"
3952 Provided
3953 this error message is successfully sent, the Exim receiving process
3954 exits with a return code of zero. If not, the return code is 2 if the problem
3955 is that the original message has no recipients, or 1 any other error. This is
3956 the default &%-oe%&&'x'& option if Exim is called as &'rmail'&.
3958 .vitem &%-oem%&
3959 .oindex "&%-oem%&"
3960 .cindex "error" "reporting"
3961 .cindex "return code" "for &%-oem%&"
3962 This is the same as &%-oee%&, except that Exim always exits with a non-zero
3963 return code, whether or not the error message was successfully sent.
3964 This is the default &%-oe%&&'x'& option, unless Exim is called as &'rmail'&.
3966 .vitem &%-oep%&
3967 .oindex "&%-oep%&"
3968 .cindex "error" "reporting"
3969 If an error is detected while a non-SMTP message is being received, the
3970 error is reported by writing a message to the standard error file (stderr).
3971 .cindex "return code" "for &%-oep%&"
3972 The return code is 1 for all errors.
3974 .vitem &%-oeq%&
3975 .oindex "&%-oeq%&"
3976 .cindex "error" "reporting"
3977 This option is supported for compatibility with Sendmail, but has the same
3978 effect as &%-oep%&.
3980 .vitem &%-oew%&
3981 .oindex "&%-oew%&"
3982 .cindex "error" "reporting"
3983 This option is supported for compatibility with Sendmail, but has the same
3984 effect as &%-oem%&.
3986 .vitem &%-oi%&
3987 .oindex "&%-oi%&"
3988 .cindex "dot" "in incoming non-SMTP message"
3989 This option, which has the same effect as &%-i%&, specifies that a dot on a
3990 line by itself should not terminate an incoming, non-SMTP message. Otherwise, a
3991 single dot does terminate, though Exim does no special processing for other
3992 lines that start with a dot. This option is set by default if Exim is called as
3993 &'rmail'&. See also &%-ti%&.
3995 .vitem &%-oitrue%&
3996 .oindex "&%-oitrue%&"
3997 This option is treated as synonymous with &%-oi%&.
3999 .vitem &%-oMa%&&~<&'host&~address'&>
4000 .oindex "&%-oMa%&"
4001 .cindex "sender" "host address, specifying for local message"
4002 A number of options starting with &%-oM%& can be used to set values associated