Implement %M datestamping in log filenames.
[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 "4.74"
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>21 Jan 2011</date>
176 <author><firstname>Exim</firstname><surname>Maintainers</surname></author>
177 <authorinitials>EM</authorinitials>
178 <revhistory><revision>
179 <revnumber>4.74</revnumber>
180 <date>21 Jan 2011</date>
181 <authorinitials>EM</authorinitials>
182 </revision></revhistory>
183 <copyright><year>2011</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!
370 .new
371 .cindex "documentation"
372 This edition of the Exim specification applies to version &version; of Exim.
373 Substantive changes from the &previousversion; edition are marked in some
374 renditions of the document; this paragraph is so marked if the rendition is
375 capable of showing a change indicator.
376 .wen
378 This document is very much a reference manual; it is not a tutorial. The reader
379 is expected to have some familiarity with the SMTP mail transfer protocol and
380 with general Unix system administration. Although there are some discussions
381 and examples in places, the information is mostly organized in a way that makes
382 it easy to look up, rather than in a natural order for sequential reading.
383 Furthermore, the manual aims to cover every aspect of Exim in detail, including
384 a number of rarely-used, special-purpose features that are unlikely to be of
385 very wide interest.
387 .cindex "books about Exim"
388 An &"easier"& discussion of Exim which provides more in-depth explanatory,
389 introductory, and tutorial material can be found in a book entitled &'The Exim
390 SMTP Mail Server'& (second edition, 2007), published by UIT Cambridge
391 (&url(
393 This book also contains a chapter that gives a general introduction to SMTP and
394 Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
395 with the latest release of Exim. (Note that the earlier book about Exim,
396 published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
398 .cindex "Debian" "information sources"
399 If you are using a Debian distribution of Exim, you will find information about
400 Debian-specific features in the file
401 &_/usr/share/doc/exim4-base/README.Debian_&.
402 The command &(man update-exim.conf)& is another source of Debian-specific
403 information.
405 .cindex "&_doc/NewStuff_&"
406 .cindex "&_doc/ChangeLog_&"
407 .cindex "change log"
408 As the program develops, there may be features in newer versions that have not
409 yet made it into this document, which is updated only when the most significant
410 digit of the fractional part of the version number changes. Specifications of
411 new features that are not yet in this manual are placed in the file
412 &_doc/NewStuff_& in the Exim distribution.
414 Some features may be classified as &"experimental"&. These may change
415 incompatibly while they are developing, or even be withdrawn. For this reason,
416 they are not documented in this manual. Information about experimental features
417 can be found in the file &_doc/experimental.txt_&.
419 All changes to the program (whether new features, bug fixes, or other kinds of
420 change) are noted briefly in the file called &_doc/ChangeLog_&.
422 .cindex "&_doc/spec.txt_&"
423 This specification itself is available as an ASCII file in &_doc/spec.txt_& so
424 that it can easily be searched with a text editor. Other files in the &_doc_&
425 directory are:
427 .table2 100pt
428 .row &_OptionLists.txt_& "list of all options in alphabetical order"
429 .row &_dbm.discuss.txt_& "discussion about DBM libraries"
430 .row &_exim.8_& "a man page of Exim's command line options"
431 .row &_experimental.txt_& "documentation of experimental features"
432 .row &_filter.txt_& "specification of the filter language"
433 .row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
434 .row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
435 .endtable
437 The main specification and the specification of the filtering language are also
438 available in other formats (HTML, PostScript, PDF, and Texinfo). Section
439 &<<SECTavail>>& below tells you how to get hold of these.
443 .section "FTP and web sites" "SECID2"
444 .cindex "web site"
445 .cindex "FTP site"
446 The primary site for Exim source distributions is currently the University of
447 Cambridge's FTP site, whose contents are described in &'Where to find the Exim
448 distribution'& below. In addition, there is a web site and an FTP site at
449 & These are now also hosted at the University of Cambridge. The
450 & site was previously hosted for a number of years by Energis
451 Squared, formerly Planet Online Ltd, whose support I gratefully acknowledge.
453 .cindex "wiki"
454 .cindex "FAQ"
455 As well as Exim distribution tar files, the Exim web site contains a number of
456 differently formatted versions of the documentation. A recent addition to the
457 online information is the Exim wiki (&url(,
458 which contains what used to be a separate FAQ, as well as various other
459 examples, tips, and know-how that have been contributed by Exim users.
461 .cindex Bugzilla
462 An Exim Bugzilla exists at &url( You can use
463 this to report bugs, and also to add items to the wish list. Please search
464 first to check that you are not duplicating a previous entry.
468 .section "Mailing lists" "SECID3"
469 .cindex "mailing lists" "for Exim users"
470 The following Exim mailing lists exist:
472 .table2 140pt
473 .row &''& "General discussion list"
474 .row &''& "Discussion of bugs, enhancements, etc."
475 .row &''& "Moderated, low volume announcements list"
476 .row &''& "Discussion of long-term development"
477 .endtable
479 You can subscribe to these lists, change your existing subscriptions, and view
480 or search the archives via the mailing lists link on the Exim home page.
481 .cindex "Debian" "mailing list for"
482 If you are using a Debian distribution of Exim, you may wish to subscribe to
483 the Debian-specific mailing list &''&
484 via this web page:
485 .display
486 &url(
487 .endd
488 Please ask Debian-specific questions on this list and not on the general Exim
489 lists.
491 .section "Exim training" "SECID4"
492 .cindex "training courses"
493 Training courses in Cambridge (UK) used to be run annually by the author of
494 Exim, before he retired. At the time of writing, there are no plans to run
495 further Exim courses in Cambridge. However, if that changes, relevant
496 information will be posted at &url(
498 .section "Bug reports" "SECID5"
499 .cindex "bug reports"
500 .cindex "reporting bugs"
501 Reports of obvious bugs can be emailed to &''& or reported
502 via the Bugzilla (&url( However, if you are unsure
503 whether some behaviour is a bug or not, the best thing to do is to post a
504 message to the &'exim-dev'& mailing list and have it discussed.
508 .section "Where to find the Exim distribution" "SECTavail"
509 .cindex "FTP site"
510 .cindex "distribution" "ftp site"
511 The master ftp site for the Exim distribution is
512 .display
513 &**&
514 .endd
515 This is mirrored by
516 .display
517 &**&
518 .endd
519 The file references that follow are relative to the &_exim_& directories at
520 these sites. There are now quite a number of independent mirror sites around
521 the world. Those that I know about are listed in the file called &_Mirrors_&.
523 Within the &_exim_& directory there are subdirectories called &_exim3_& (for
524 previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
525 distributions), and &_Testing_& for testing versions. In the &_exim4_&
526 subdirectory, the current release can always be found in files called
527 .display
528 &_exim-n.nn.tar.gz_&
529 &_exim-n.nn.tar.bz2_&
530 .endd
531 where &'n.nn'& is the highest such version number in the directory. The two
532 files contain identical data; the only difference is the type of compression.
533 The &_.bz2_& file is usually a lot smaller than the &_.gz_& file.
535 .cindex "distribution" "signing details"
536 .cindex "distribution" "public key"
537 .cindex "public key for signed distribution"
538 The distributions are currently signed with Nigel Metheringham's GPG key. The
539 corresponding public key is available from a number of keyservers, and there is
540 also a copy in the file &_nigel-pubkey.asc_&. The signatures for the tar bundles are
541 in:
542 .display
543 &_exim-n.nn.tar.gz.asc_&
544 &_exim-n.nn.tar.bz2.asc_&
545 .endd
546 For each released version, the log of changes is made separately available in a
547 separate file in the directory &_ChangeLogs_& so that it is possible to
548 find out what has changed without having to download the entire distribution.
550 .cindex "documentation" "available formats"
551 The main distribution contains ASCII versions of this specification and other
552 documentation; other formats of the documents are available in separate files
553 inside the &_exim4_& directory of the FTP site:
554 .display
555 &_exim-html-n.nn.tar.gz_&
556 &_exim-pdf-n.nn.tar.gz_&
557 &_exim-postscript-n.nn.tar.gz_&
558 &_exim-texinfo-n.nn.tar.gz_&
559 .endd
560 These tar files contain only the &_doc_& directory, not the complete
561 distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
564 .section "Limitations" "SECID6"
565 .ilist
566 .cindex "limitations of Exim"
567 .cindex "bang paths" "not handled by Exim"
568 Exim is designed for use as an Internet MTA, and therefore handles addresses in
569 RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
570 simple two-component bang paths can be converted by a straightforward rewriting
571 configuration. This restriction does not prevent Exim from being interfaced to
572 UUCP as a transport mechanism, provided that domain addresses are used.
573 .next
574 .cindex "domainless addresses"
575 .cindex "address" "without domain"
576 Exim insists that every address it handles has a domain attached. For incoming
577 local messages, domainless addresses are automatically qualified with a
578 configured domain value. Configuration options specify from which remote
579 systems unqualified addresses are acceptable. These are then qualified on
580 arrival.
581 .next
582 .cindex "transport" "external"
583 .cindex "external transports"
584 The only external transport mechanisms that are currently implemented are SMTP
585 and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
586 transport is available, and there are facilities for writing messages to files
587 and pipes, optionally in &'batched SMTP'& format; these facilities can be used
588 to send messages to other transport mechanisms such as UUCP, provided they can
589 handle domain-style addresses. Batched SMTP input is also catered for.
590 .next
591 Exim is not designed for storing mail for dial-in hosts. When the volumes of
592 such mail are large, it is better to get the messages &"delivered"& into files
593 (that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
594 other means.
595 .next
596 Although Exim does have basic facilities for scanning incoming messages, these
597 are not comprehensive enough to do full virus or spam scanning. Such operations
598 are best carried out using additional specialized software packages. If you
599 compile Exim with the content-scanning extension, straightforward interfaces to
600 a number of common scanners are provided.
601 .endlist
604 .section "Run time configuration" "SECID7"
605 Exim's run time configuration is held in a single text file that is divided
606 into a number of sections. The entries in this file consist of keywords and
607 values, in the style of Smail 3 configuration files. A default configuration
608 file which is suitable for simple online installations is provided in the
609 distribution, and is described in chapter &<<CHAPdefconfil>>& below.
612 .section "Calling interface" "SECID8"
613 .cindex "Sendmail compatibility" "command line interface"
614 Like many MTAs, Exim has adopted the Sendmail command line interface so that it
615 can be a straight replacement for &_/usr/lib/sendmail_& or
616 &_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
617 about Sendmail in order to run Exim. For actions other than sending messages,
618 Sendmail-compatible options also exist, but those that produce output (for
619 example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
620 format. There are also some additional options that are compatible with Smail
621 3, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
622 documents all Exim's command line options. This information is automatically
623 made into the man page that forms part of the Exim distribution.
625 Control of messages on the queue can be done via certain privileged command
626 line options. There is also an optional monitor program called &'eximon'&,
627 which displays current information in an X window, and which contains a menu
628 interface to Exim's command line administration options.
632 .section "Terminology" "SECID9"
633 .cindex "terminology definitions"
634 .cindex "body of message" "definition of"
635 The &'body'& of a message is the actual data that the sender wants to transmit.
636 It is the last part of a message, and is separated from the &'header'& (see
637 below) by a blank line.
639 .cindex "bounce message" "definition of"
640 When a message cannot be delivered, it is normally returned to the sender in a
641 delivery failure message or a &"non-delivery report"& (NDR). The term
642 &'bounce'& is commonly used for this action, and the error reports are often
643 called &'bounce messages'&. This is a convenient shorthand for &"delivery
644 failure error report"&. Such messages have an empty sender address in the
645 message's &'envelope'& (see below) to ensure that they cannot themselves give
646 rise to further bounce messages.
648 The term &'default'& appears frequently in this manual. It is used to qualify a
649 value which is used in the absence of any setting in the configuration. It may
650 also qualify an action which is taken unless a configuration setting specifies
651 otherwise.
653 The term &'defer'& is used when the delivery of a message to a specific
654 destination cannot immediately take place for some reason (a remote host may be
655 down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
656 until a later time.
658 The word &'domain'& is sometimes used to mean all but the first component of a
659 host's name. It is &'not'& used in that sense here, where it normally refers to
660 the part of an email address following the @ sign.
662 .cindex "envelope, definition of"
663 .cindex "sender" "definition of"
664 A message in transit has an associated &'envelope'&, as well as a header and a
665 body. The envelope contains a sender address (to which bounce messages should
666 be delivered), and any number of recipient addresses. References to the
667 sender or the recipients of a message usually mean the addresses in the
668 envelope. An MTA uses these addresses for delivery, and for returning bounce
669 messages, not the addresses that appear in the header lines.
671 .cindex "message" "header, definition of"
672 .cindex "header section" "definition of"
673 The &'header'& of a message is the first part of a message's text, consisting
674 of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
675 &'Subject:'&, etc. Long header lines can be split over several text lines by
676 indenting the continuations. The header is separated from the body by a blank
677 line.
679 .cindex "local part" "definition of"
680 .cindex "domain" "definition of"
681 The term &'local part'&, which is taken from RFC 2822, is used to refer to that
682 part of an email address that precedes the @ sign. The part that follows the
683 @ sign is called the &'domain'& or &'mail domain'&.
685 .cindex "local delivery" "definition of"
686 .cindex "remote delivery, definition of"
687 The terms &'local delivery'& and &'remote delivery'& are used to distinguish
688 delivery to a file or a pipe on the local host from delivery by SMTP over
689 TCP/IP to another host. As far as Exim is concerned, all hosts other than the
690 host it is running on are &'remote'&.
692 .cindex "return path" "definition of"
693 &'Return path'& is another name that is used for the sender address in a
694 message's envelope.
696 .cindex "queue" "definition of"
697 The term &'queue'& is used to refer to the set of messages awaiting delivery,
698 because this term is in widespread use in the context of MTAs. However, in
699 Exim's case the reality is more like a pool than a queue, because there is
700 normally no ordering of waiting messages.
702 .cindex "queue runner" "definition of"
703 The term &'queue runner'& is used to describe a process that scans the queue
704 and attempts to deliver those messages whose retry times have come. This term
705 is used by other MTAs, and also relates to the command &%runq%&, but in Exim
706 the waiting messages are normally processed in an unpredictable order.
708 .cindex "spool directory" "definition of"
709 The term &'spool directory'& is used for a directory in which Exim keeps the
710 messages on its queue &-- that is, those that it is in the process of
711 delivering. This should not be confused with the directory in which local
712 mailboxes are stored, which is called a &"spool directory"& by some people. In
713 the Exim documentation, &"spool"& is always used in the first sense.
720 . ////////////////////////////////////////////////////////////////////////////
721 . ////////////////////////////////////////////////////////////////////////////
723 .chapter "Incorporated code" "CHID2"
724 .cindex "incorporated code"
725 .cindex "regular expressions" "library"
726 .cindex "PCRE"
727 A number of pieces of external code are included in the Exim distribution.
729 .ilist
730 Regular expressions are supported in the main Exim program and in the
731 Exim monitor using the freely-distributable PCRE library, copyright
732 &copy; University of Cambridge. The source to PCRE is no longer shipped with
733 Exim, so you will need to use the version of PCRE shipped with your system,
734 or obtain and install the full version of the library from
735 &url(
736 .next
737 .cindex "cdb" "acknowledgment"
738 Support for the cdb (Constant DataBase) lookup method is provided by code
739 contributed by Nigel Metheringham of (at the time he contributed it) Planet
740 Online Ltd. The implementation is completely contained within the code of Exim.
741 It does not link against an external cdb library. The code contains the
742 following statements:
744 .blockquote
745 Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
747 This program is free software; you can redistribute it and/or modify it under
748 the terms of the GNU General Public License as published by the Free Software
749 Foundation; either version 2 of the License, or (at your option) any later
750 version.
751 This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
752 the spec and sample code for cdb can be obtained from
753 &url( This implementation borrows
754 some code from Dan Bernstein's implementation (which has no license
755 restrictions applied to it).
756 .endblockquote
757 .next
758 .cindex "SPA authentication"
759 .cindex "Samba project"
760 .cindex "Microsoft Secure Password Authentication"
761 Client support for Microsoft's &'Secure Password Authentication'& is provided
762 by code contributed by Marc Prud'hommeaux. Server support was contributed by
763 Tom Kistner. This includes code taken from the Samba project, which is released
764 under the Gnu GPL.
765 .next
766 .cindex "Cyrus"
767 .cindex "&'pwcheck'& daemon"
768 .cindex "&'pwauthd'& daemon"
769 Support for calling the Cyrus &'pwcheck'& and &'saslauthd'& daemons is provided
770 by code taken from the Cyrus-SASL library and adapted by Alexander S.
771 Sabourenkov. The permission notice appears below, in accordance with the
772 conditions expressed therein.
774 .blockquote
775 Copyright &copy; 2001 Carnegie Mellon University. All rights reserved.
777 Redistribution and use in source and binary forms, with or without
778 modification, are permitted provided that the following conditions
779 are met:
781 .olist
782 Redistributions of source code must retain the above copyright
783 notice, this list of conditions and the following disclaimer.
784 .next
785 Redistributions in binary form must reproduce the above copyright
786 notice, this list of conditions and the following disclaimer in
787 the documentation and/or other materials provided with the
788 distribution.
789 .next
790 The name &"Carnegie Mellon University"& must not be used to
791 endorse or promote products derived from this software without
792 prior written permission. For permission or any other legal
793 details, please contact
794 .display
795 Office of Technology Transfer
796 Carnegie Mellon University
797 5000 Forbes Avenue
798 Pittsburgh, PA 15213-3890
799 (412) 268-4387, fax: (412) 268-7395
801 .endd
802 .next
803 Redistributions of any form whatsoever must retain the following
804 acknowledgment:
806 &"This product includes software developed by Computing Services
807 at Carnegie Mellon University (&url("&
816 .endlist
817 .endblockquote
819 .next
820 .cindex "Exim monitor" "acknowledgment"
821 .cindex "X-windows"
822 .cindex "Athena"
823 The Exim Monitor program, which is an X-Window application, includes
824 modified versions of the Athena StripChart and TextPop widgets.
825 This code is copyright by DEC and MIT, and their permission notice appears
826 below, in accordance with the conditions expressed therein.
828 .blockquote
829 Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
830 and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
832 All Rights Reserved
834 Permission to use, copy, modify, and distribute this software and its
835 documentation for any purpose and without fee is hereby granted,
836 provided that the above copyright notice appear in all copies and that
837 both that copyright notice and this permission notice appear in
838 supporting documentation, and that the names of Digital or MIT not be
839 used in advertising or publicity pertaining to distribution of the
840 software without specific, written prior permission.
849 .endblockquote
851 .next
852 Many people have contributed code fragments, some large, some small, that were
853 not covered by any specific licence requirements. It is assumed that the
854 contributors are happy to see their code incorporated into Exim under the GPL.
855 .endlist
861 . ////////////////////////////////////////////////////////////////////////////
862 . ////////////////////////////////////////////////////////////////////////////
864 .chapter "How Exim receives and delivers mail" "CHID11" &&&
865 "Receiving and delivering mail"
868 .section "Overall philosophy" "SECID10"
869 .cindex "design philosophy"
870 Exim is designed to work efficiently on systems that are permanently connected
871 to the Internet and are handling a general mix of mail. In such circumstances,
872 most messages can be delivered immediately. Consequently, Exim does not
873 maintain independent queues of messages for specific domains or hosts, though
874 it does try to send several messages in a single SMTP connection after a host
875 has been down, and it also maintains per-host retry information.
878 .section "Policy control" "SECID11"
879 .cindex "policy control" "overview"
880 Policy controls are now an important feature of MTAs that are connected to the
881 Internet. Perhaps their most important job is to stop MTAs being abused as
882 &"open relays"& by misguided individuals who send out vast amounts of
883 unsolicited junk, and want to disguise its source. Exim provides flexible
884 facilities for specifying policy controls on incoming mail:
886 .ilist
887 .cindex "&ACL;" "introduction"
888 Exim 4 (unlike previous versions of Exim) implements policy controls on
889 incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
890 series of statements that may either grant or deny access. ACLs can be used at
891 several places in the SMTP dialogue while receiving a message from a remote
892 host. However, the most common places are after each RCPT command, and at the
893 very end of the message. The sysadmin can specify conditions for accepting or
894 rejecting individual recipients or the entire message, respectively, at these
895 two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
896 error code.
897 .next
898 An ACL is also available for locally generated, non-SMTP messages. In this
899 case, the only available actions are to accept or deny the entire message.
900 .next
901 When Exim is compiled with the content-scanning extension, facilities are
902 provided in the ACL mechanism for passing the message to external virus and/or
903 spam scanning software. The result of such a scan is passed back to the ACL,
904 which can then use it to decide what to do with the message.
905 .next
906 When a message has been received, either from a remote host or from the local
907 host, but before the final acknowledgment has been sent, a locally supplied C
908 function called &[local_scan()]& can be run to inspect the message and decide
909 whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
910 is accepted, the list of recipients can be modified by the function.
911 .next
912 Using the &[local_scan()]& mechanism is another way of calling external scanner
913 software. The &%SA-Exim%& add-on package works this way. It does not require
914 Exim to be compiled with the content-scanning extension.
915 .next
916 After a message has been accepted, a further checking mechanism is available in
917 the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
918 runs at the start of every delivery process.
919 .endlist
923 .section "User filters" "SECID12"
924 .cindex "filter" "introduction"
925 .cindex "Sieve filter"
926 In a conventional Exim configuration, users are able to run private filters by
927 setting up appropriate &_.forward_& files in their home directories. See
928 chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
929 configuration needed to support this, and the separate document entitled
930 &'Exim's interfaces to mail filtering'& for user details. Two different kinds
931 of filtering are available:
933 .ilist
934 Sieve filters are written in the standard filtering language that is defined
935 by RFC 3028.
936 .next
937 Exim filters are written in a syntax that is unique to Exim, but which is more
938 powerful than Sieve, which it pre-dates.
939 .endlist
941 User filters are run as part of the routing process, described below.
945 .section "Message identification" "SECTmessiden"
946 .cindex "message ids" "details of format"
947 .cindex "format" "of message id"
948 .cindex "id of message"
949 .cindex "base62"
950 .cindex "base36"
951 .cindex "Darwin"
952 .cindex "Cygwin"
953 Every message handled by Exim is given a &'message id'& which is sixteen
954 characters long. It is divided into three parts, separated by hyphens, for
955 example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
956 normally encoding numbers in base 62. However, in the Darwin operating
957 system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
958 (avoiding the use of lower case letters) is used instead, because the message
959 id is used to construct file names, and the names of files in those systems are
960 not always case-sensitive.
962 .cindex "pid (process id)" "re-use of"
963 The detail of the contents of the message id have changed as Exim has evolved.
964 Earlier versions relied on the operating system not re-using a process id (pid)
965 within one second. On modern operating systems, this assumption can no longer
966 be made, so the algorithm had to be changed. To retain backward compatibility,
967 the format of the message id was retained, which is why the following rules are
968 somewhat eccentric:
970 .ilist
971 The first six characters of the message id are the time at which the message
972 started to be received, to a granularity of one second. That is, this field
973 contains the number of seconds since the start of the epoch (the normal Unix
974 way of representing the date and time of day).
975 .next
976 After the first hyphen, the next six characters are the id of the process that
977 received the message.
978 .next
979 There are two different possibilities for the final two characters:
980 .olist
981 .oindex "&%localhost_number%&"
982 If &%localhost_number%& is not set, this value is the fractional part of the
983 time of reception, normally in units of 1/2000 of a second, but for systems
984 that must use base 36 instead of base 62 (because of case-insensitive file
985 systems), the units are 1/1000 of a second.
986 .next
987 If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
988 the fractional part of the time, which in this case is in units of 1/200
989 (1/100) of a second.
990 .endlist
991 .endlist
993 After a message has been received, Exim waits for the clock to tick at the
994 appropriate resolution before proceeding, so that if another message is
995 received by the same process, or by another process with the same (re-used)
996 pid, it is guaranteed that the time will be different. In most cases, the clock
997 will already have ticked while the message was being received.
1000 .section "Receiving mail" "SECID13"
1001 .cindex "receiving mail"
1002 .cindex "message" "reception"
1003 The only way Exim can receive mail from another host is using SMTP over
1004 TCP/IP, in which case the sender and recipient addresses are transferred using
1005 SMTP commands. However, from a locally running process (such as a user's MUA),
1006 there are several possibilities:
1008 .ilist
1009 If the process runs Exim with the &%-bm%& option, the message is read
1010 non-interactively (usually via a pipe), with the recipients taken from the
1011 command line, or from the body of the message if &%-t%& is also used.
1012 .next
1013 If the process runs Exim with the &%-bS%& option, the message is also read
1014 non-interactively, but in this case the recipients are listed at the start of
1015 the message in a series of SMTP RCPT commands, terminated by a DATA
1016 command. This is so-called &"batch SMTP"& format,
1017 but it isn't really SMTP. The SMTP commands are just another way of passing
1018 envelope addresses in a non-interactive submission.
1019 .next
1020 If the process runs Exim with the &%-bs%& option, the message is read
1021 interactively, using the SMTP protocol. A two-way pipe is normally used for
1022 passing data between the local process and the Exim process.
1023 This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
1024 example, the ACLs for SMTP commands are used for this form of submission.
1025 .next
1026 A local process may also make a TCP/IP call to the host's loopback address
1027 ( or any other of its IP addresses. When receiving messages, Exim
1028 does not treat the loopback address specially. It treats all such connections
1029 in the same way as connections from other hosts.
1030 .endlist
1033 .cindex "message sender, constructed by Exim"
1034 .cindex "sender" "constructed by Exim"
1035 In the three cases that do not involve TCP/IP, the sender address is
1036 constructed from the login name of the user that called Exim and a default
1037 qualification domain (which can be set by the &%qualify_domain%& configuration
1038 option). For local or batch SMTP, a sender address that is passed using the
1039 SMTP MAIL command is ignored. However, the system administrator may allow
1040 certain users (&"trusted users"&) to specify a different sender address
1041 unconditionally, or all users to specify certain forms of different sender
1042 address. The &%-f%& option or the SMTP MAIL command is used to specify these
1043 different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1044 users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
1045 users to change sender addresses.
1047 Messages received by either of the non-interactive mechanisms are subject to
1048 checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1049 (either over TCP/IP, or interacting with a local process) can be checked by a
1050 number of ACLs that operate at different times during the SMTP session. Either
1051 individual recipients, or the entire message, can be rejected if local policy
1052 requirements are not met. The &[local_scan()]& function (see chapter
1053 &<<CHAPlocalscan>>&) is run for all incoming messages.
1055 Exim can be configured not to start a delivery process when a message is
1056 received; this can be unconditional, or depend on the number of incoming SMTP
1057 connections or the system load. In these situations, new messages wait on the
1058 queue until a queue runner process picks them up. However, in standard
1059 configurations under normal conditions, delivery is started as soon as a
1060 message is received.
1066 .section "Handling an incoming message" "SECID14"
1067 .cindex "spool directory" "files that hold a message"
1068 .cindex "file" "how a message is held"
1069 When Exim accepts a message, it writes two files in its spool directory. The
1070 first contains the envelope information, the current status of the message, and
1071 the header lines, and the second contains the body of the message. The names of
1072 the two spool files consist of the message id, followed by &`-H`& for the
1073 file containing the envelope and header, and &`-D`& for the data file.
1075 .cindex "spool directory" "&_input_& sub-directory"
1076 By default all these message files are held in a single directory called
1077 &_input_& inside the general Exim spool directory. Some operating systems do
1078 not perform very well if the number of files in a directory gets large; to
1079 improve performance in such cases, the &%split_spool_directory%& option can be
1080 used. This causes Exim to split up the input files into 62 sub-directories
1081 whose names are single letters or digits. When this is done, the queue is
1082 processed one sub-directory at a time instead of all at once, which can improve
1083 overall performance even when there are not enough files in each directory to
1084 affect file system performance.
1086 The envelope information consists of the address of the message's sender and
1087 the addresses of the recipients. This information is entirely separate from
1088 any addresses contained in the header lines. The status of the message includes
1089 a list of recipients who have already received the message. The format of the
1090 first spool file is described in chapter &<<CHAPspool>>&.
1092 .cindex "rewriting" "addresses"
1093 Address rewriting that is specified in the rewrite section of the configuration
1094 (see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
1095 both in the header lines and the envelope, at the time the message is accepted.
1096 If during the course of delivery additional addresses are generated (for
1097 example, via aliasing), these new addresses are rewritten as soon as they are
1098 generated. At the time a message is actually delivered (transported) further
1099 rewriting can take place; because this is a transport option, it can be
1100 different for different forms of delivery. It is also possible to specify the
1101 addition or removal of certain header lines at the time the message is
1102 delivered (see chapters &<<CHAProutergeneric>>& and
1103 &<<CHAPtransportgeneric>>&).
1107 .section "Life of a message" "SECID15"
1108 .cindex "message" "life of"
1109 .cindex "message" "frozen"
1110 A message remains in the spool directory until it is completely delivered to
1111 its recipients or to an error address, or until it is deleted by an
1112 administrator or by the user who originally created it. In cases when delivery
1113 cannot proceed &-- for example, when a message can neither be delivered to its
1114 recipients nor returned to its sender, the message is marked &"frozen"& on the
1115 spool, and no more deliveries are attempted.
1117 .cindex "frozen messages" "thawing"
1118 .cindex "message" "thawing frozen"
1119 An administrator can &"thaw"& such messages when the problem has been
1120 corrected, and can also freeze individual messages by hand if necessary. In
1121 addition, an administrator can force a delivery error, causing a bounce message
1122 to be sent.
1124 .oindex "&%timeout_frozen_after%&"
1125 .oindex "&%ignore_bounce_errors_after%&"
1126 There are options called &%ignore_bounce_errors_after%& and
1127 &%timeout_frozen_after%&, which discard frozen messages after a certain time.
1128 The first applies only to frozen bounces, the second to any frozen messages.
1130 .cindex "message" "log file for"
1131 .cindex "log" "file for each message"
1132 While Exim is working on a message, it writes information about each delivery
1133 attempt to its main log file. This includes successful, unsuccessful, and
1134 delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1135 lines are also written to a separate &'message log'& file for each message.
1136 These logs are solely for the benefit of the administrator, and are normally
1137 deleted along with the spool files when processing of a message is complete.
1138 The use of individual message logs can be disabled by setting
1139 &%no_message_logs%&; this might give an improvement in performance on very busy
1140 systems.
1142 .cindex "journal file"
1143 .cindex "file" "journal"
1144 All the information Exim itself needs to set up a delivery is kept in the first
1145 spool file, along with the header lines. When a successful delivery occurs, the
1146 address is immediately written at the end of a journal file, whose name is the
1147 message id followed by &`-J`&. At the end of a delivery run, if there are some
1148 addresses left to be tried again later, the first spool file (the &`-H`& file)
1149 is updated to indicate which these are, and the journal file is then deleted.
1150 Updating the spool file is done by writing a new file and renaming it, to
1151 minimize the possibility of data loss.
1153 Should the system or the program crash after a successful delivery but before
1154 the spool file has been updated, the journal is left lying around. The next
1155 time Exim attempts to deliver the message, it reads the journal file and
1156 updates the spool file before proceeding. This minimizes the chances of double
1157 deliveries caused by crashes.
1161 .section "Processing an address for delivery" "SECTprocaddress"
1162 .cindex "drivers" "definition of"
1163 .cindex "router" "definition of"
1164 .cindex "transport" "definition of"
1165 The main delivery processing elements of Exim are called &'routers'& and
1166 &'transports'&, and collectively these are known as &'drivers'&. Code for a
1167 number of them is provided in the source distribution, and compile-time options
1168 specify which ones are included in the binary. Run time options specify which
1169 ones are actually used for delivering messages.
1171 .cindex "drivers" "instance definition"
1172 Each driver that is specified in the run time configuration is an &'instance'&
1173 of that particular driver type. Multiple instances are allowed; for example,
1174 you can set up several different &(smtp)& transports, each with different
1175 option values that might specify different ports or different timeouts. Each
1176 instance has its own identifying name. In what follows we will normally use the
1177 instance name when discussing one particular instance (that is, one specific
1178 configuration of the driver), and the generic driver name when discussing
1179 the driver's features in general.
1181 A &'router'& is a driver that operates on an address, either determining how
1182 its delivery should happen, by assigning it to a specific transport, or
1183 converting the address into one or more new addresses (for example, via an
1184 alias file). A router may also explicitly choose to fail an address, causing it
1185 to be bounced.
1187 A &'transport'& is a driver that transmits a copy of the message from Exim's
1188 spool to some destination. There are two kinds of transport: for a &'local'&
1189 transport, the destination is a file or a pipe on the local host, whereas for a
1190 &'remote'& transport the destination is some other host. A message is passed
1191 to a specific transport as a result of successful routing. If a message has
1192 several recipients, it may be passed to a number of different transports.
1194 .cindex "preconditions" "definition of"
1195 An address is processed by passing it to each configured router instance in
1196 turn, subject to certain preconditions, until a router accepts the address or
1197 specifies that it should be bounced. We will describe this process in more
1198 detail shortly. First, as a simple example, we consider how each recipient
1199 address in a message is processed in a small configuration of three routers.
1201 To make this a more concrete example, it is described in terms of some actual
1202 routers, but remember, this is only an example. You can configure Exim's
1203 routers in many different ways, and there may be any number of routers in a
1204 configuration.
1206 The first router that is specified in a configuration is often one that handles
1207 addresses in domains that are not recognized specially by the local host. These
1208 are typically addresses for arbitrary domains on the Internet. A precondition
1209 is set up which looks for the special domains known to the host (for example,
1210 its own domain name), and the router is run for addresses that do &'not'&
1211 match. Typically, this is a router that looks up domains in the DNS in order to
1212 find the hosts to which this address routes. If it succeeds, the address is
1213 assigned to a suitable SMTP transport; if it does not succeed, the router is
1214 configured to fail the address.
1216 The second router is reached only when the domain is recognized as one that
1217 &"belongs"& to the local host. This router does redirection &-- also known as
1218 aliasing and forwarding. When it generates one or more new addresses from the
1219 original, each of them is routed independently from the start. Otherwise, the
1220 router may cause an address to fail, or it may simply decline to handle the
1221 address, in which case the address is passed to the next router.
1223 The final router in many configurations is one that checks to see if the
1224 address belongs to a local mailbox. The precondition may involve a check to
1225 see if the local part is the name of a login account, or it may look up the
1226 local part in a file or a database. If its preconditions are not met, or if
1227 the router declines, we have reached the end of the routers. When this happens,
1228 the address is bounced.
1232 .section "Processing an address for verification" "SECID16"
1233 .cindex "router" "for verification"
1234 .cindex "verifying address" "overview"
1235 As well as being used to decide how to deliver to an address, Exim's routers
1236 are also used for &'address verification'&. Verification can be requested as
1237 one of the checks to be performed in an ACL for incoming messages, on both
1238 sender and recipient addresses, and it can be tested using the &%-bv%& and
1239 &%-bvs%& command line options.
1241 When an address is being verified, the routers are run in &"verify mode"&. This
1242 does not affect the way the routers work, but it is a state that can be
1243 detected. By this means, a router can be skipped or made to behave differently
1244 when verifying. A common example is a configuration in which the first router
1245 sends all messages to a message-scanning program, unless they have been
1246 previously scanned. Thus, the first router accepts all addresses without any
1247 checking, making it useless for verifying. Normally, the &%no_verify%& option
1248 would be set for such a router, causing it to be skipped in verify mode.
1253 .section "Running an individual router" "SECTrunindrou"
1254 .cindex "router" "running details"
1255 .cindex "preconditions" "checking"
1256 .cindex "router" "result of running"
1257 As explained in the example above, a number of preconditions are checked before
1258 running a router. If any are not met, the router is skipped, and the address is
1259 passed to the next router. When all the preconditions on a router &'are'& met,
1260 the router is run. What happens next depends on the outcome, which is one of
1261 the following:
1263 .ilist
1264 &'accept'&: The router accepts the address, and either assigns it to a
1265 transport, or generates one or more &"child"& addresses. Processing the
1266 original address ceases,
1267 .oindex "&%unseen%&"
1268 unless the &%unseen%& option is set on the router. This option
1269 can be used to set up multiple deliveries with different routing (for example,
1270 for keeping archive copies of messages). When &%unseen%& is set, the address is
1271 passed to the next router. Normally, however, an &'accept'& return marks the
1272 end of routing.
1274 Any child addresses generated by the router are processed independently,
1275 starting with the first router by default. It is possible to change this by
1276 setting the &%redirect_router%& option to specify which router to start at for
1277 child addresses. Unlike &%pass_router%& (see below) the router specified by
1278 &%redirect_router%& may be anywhere in the router configuration.
1279 .next
1280 &'pass'&: The router recognizes the address, but cannot handle it itself. It
1281 requests that the address be passed to another router. By default the address
1282 is passed to the next router, but this can be changed by setting the
1283 &%pass_router%& option. However, (unlike &%redirect_router%&) the named router
1284 must be below the current router (to avoid loops).
1285 .next
1286 &'decline'&: The router declines to accept the address because it does not
1287 recognize it at all. By default, the address is passed to the next router, but
1288 this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1289 set, all the remaining routers are skipped. In effect, &%no_more%& converts
1290 &'decline'& into &'fail'&.
1291 .next
1292 &'fail'&: The router determines that the address should fail, and queues it for
1293 the generation of a bounce message. There is no further processing of the
1294 original address unless &%unseen%& is set on the router.
1295 .next
1296 &'defer'&: The router cannot handle the address at the present time. (A
1297 database may be offline, or a DNS lookup may have timed out.) No further
1298 processing of the address happens in this delivery attempt. It is tried again
1299 next time the message is considered for delivery.
1300 .next
1301 &'error'&: There is some error in the router (for example, a syntax error in
1302 its configuration). The action is as for defer.
1303 .endlist
1305 If an address reaches the end of the routers without having been accepted by
1306 any of them, it is bounced as unrouteable. The default error message in this
1307 situation is &"unrouteable address"&, but you can set your own message by
1308 making use of the &%cannot_route_message%& option. This can be set for any
1309 router; the value from the last router that &"saw"& the address is used.
1311 Sometimes while routing you want to fail a delivery when some conditions are
1312 met but others are not, instead of passing the address on for further routing.
1313 You can do this by having a second router that explicitly fails the delivery
1314 when the relevant conditions are met. The &(redirect)& router has a &"fail"&
1315 facility for this purpose.
1318 .section "Duplicate addresses" "SECID17"
1319 .cindex "case of local parts"
1320 .cindex "address duplicate, discarding"
1321 .cindex "duplicate addresses"
1322 Once routing is complete, Exim scans the addresses that are assigned to local
1323 and remote transports, and discards any duplicates that it finds. During this
1324 check, local parts are treated as case-sensitive. This happens only when
1325 actually delivering a message; when testing routers with &%-bt%&, all the
1326 routed addresses are shown.
1330 .section "Router preconditions" "SECTrouprecon"
1331 .cindex "router" "preconditions, order of processing"
1332 .cindex "preconditions" "order of processing"
1333 The preconditions that are tested for each router are listed below, in the
1334 order in which they are tested. The individual configuration options are
1335 described in more detail in chapter &<<CHAProutergeneric>>&.
1337 .ilist
1338 The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
1339 the local parts handled by the router may or must have certain prefixes and/or
1340 suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1341 skipped. These conditions are tested first. When an affix is present, it is
1342 removed from the local part before further processing, including the evaluation
1343 of any other conditions.
1344 .next
1345 Routers can be designated for use only when not verifying an address, that is,
1346 only when routing it for delivery (or testing its delivery routing). If the
1347 &%verify%& option is set false, the router is skipped when Exim is verifying an
1348 address.
1349 Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1350 &%verify_recipient%&, which independently control the use of the router for
1351 sender and recipient verification. You can set these options directly if
1352 you want a router to be used for only one type of verification.
1353 .next
1354 If the &%address_test%& option is set false, the router is skipped when Exim is
1355 run with the &%-bt%& option to test an address routing. This can be helpful
1356 when the first router sends all new messages to a scanner of some sort; it
1357 makes it possible to use &%-bt%& to test subsequent delivery routing without
1358 having to simulate the effect of the scanner.
1359 .next
1360 Routers can be designated for use only when verifying an address, as
1361 opposed to routing it for delivery. The &%verify_only%& option controls this.
1362 .next
1363 Individual routers can be explicitly skipped when running the routers to
1364 check an address given in the SMTP EXPN command (see the &%expn%& option).
1365 .next
1366 If the &%domains%& option is set, the domain of the address must be in the set
1367 of domains that it defines.
1368 .next
1369 .vindex "&$local_part_prefix$&"
1370 .vindex "&$local_part$&"
1371 .vindex "&$local_part_suffix$&"
1372 If the &%local_parts%& option is set, the local part of the address must be in
1373 the set of local parts that it defines. If &%local_part_prefix%& or
1374 &%local_part_suffix%& is in use, the prefix or suffix is removed from the local
1375 part before this check. If you want to do precondition tests on local parts
1376 that include affixes, you can do so by using a &%condition%& option (see below)
1377 that uses the variables &$local_part$&, &$local_part_prefix$&, and
1378 &$local_part_suffix$& as necessary.
1379 .next
1380 .vindex "&$local_user_uid$&"
1381 .vindex "&$local_user_gid$&"
1382 .vindex "&$home$&"
1383 If the &%check_local_user%& option is set, the local part must be the name of
1384 an account on the local host. If this check succeeds, the uid and gid of the
1385 local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1386 user's home directory is placed in &$home$&; these values can be used in the
1387 remaining preconditions.
1388 .next
1389 If the &%router_home_directory%& option is set, it is expanded at this point,
1390 because it overrides the value of &$home$&. If this expansion were left till
1391 later, the value of &$home$& as set by &%check_local_user%& would be used in
1392 subsequent tests. Having two different values of &$home$& in the same router
1393 could lead to confusion.
1394 .next
1395 If the &%senders%& option is set, the envelope sender address must be in the
1396 set of addresses that it defines.
1397 .next
1398 If the &%require_files%& option is set, the existence or non-existence of
1399 specified files is tested.
1400 .next
1401 .cindex "customizing" "precondition"
1402 If the &%condition%& option is set, it is evaluated and tested. This option
1403 uses an expanded string to allow you to set up your own custom preconditions.
1404 Expanded strings are described in chapter &<<CHAPexpand>>&.
1405 .endlist
1408 Note that &%require_files%& comes near the end of the list, so you cannot use
1409 it to check for the existence of a file in which to lookup up a domain, local
1410 part, or sender. However, as these options are all expanded, you can use the
1411 &%exists%& expansion condition to make such tests within each condition. The
1412 &%require_files%& option is intended for checking files that the router may be
1413 going to use internally, or which are needed by a specific transport (for
1414 example, &_.procmailrc_&).
1418 .section "Delivery in detail" "SECID18"
1419 .cindex "delivery" "in detail"
1420 When a message is to be delivered, the sequence of events is as follows:
1422 .ilist
1423 If a system-wide filter file is specified, the message is passed to it. The
1424 filter may add recipients to the message, replace the recipients, discard the
1425 message, cause a new message to be generated, or cause the message delivery to
1426 fail. The format of the system filter file is the same as for Exim user filter
1427 files, described in the separate document entitled &'Exim's interfaces to mail
1428 filtering'&.
1429 .cindex "Sieve filter" "not available for system filter"
1430 (&*Note*&: Sieve cannot be used for system filter files.)
1432 Some additional features are available in system filters &-- see chapter
1433 &<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
1434 filter only once per delivery attempt, however many recipients it has. However,
1435 if there are several delivery attempts because one or more addresses could not
1436 be immediately delivered, the system filter is run each time. The filter
1437 condition &%first_delivery%& can be used to detect the first run of the system
1438 filter.
1439 .next
1440 Each recipient address is offered to each configured router in turn, subject to
1441 its preconditions, until one is able to handle it. If no router can handle the
1442 address, that is, if they all decline, the address is failed. Because routers
1443 can be targeted at particular domains, several locally handled domains can be
1444 processed entirely independently of each other.
1445 .next
1446 .cindex "routing" "loops in"
1447 .cindex "loop" "while routing"
1448 A router that accepts an address may assign it to a local or a remote
1449 transport. However, the transport is not run at this time. Instead, the address
1450 is placed on a list for the particular transport, which will be run later.
1451 Alternatively, the router may generate one or more new addresses (typically
1452 from alias, forward, or filter files). New addresses are fed back into this
1453 process from the top, but in order to avoid loops, a router ignores any address
1454 which has an identically-named ancestor that was processed by itself.
1455 .next
1456 When all the routing has been done, addresses that have been successfully
1457 handled are passed to their assigned transports. When local transports are
1458 doing real local deliveries, they handle only one address at a time, but if a
1459 local transport is being used as a pseudo-remote transport (for example, to
1460 collect batched SMTP messages for transmission by some other means) multiple
1461 addresses can be handled. Remote transports can always handle more than one
1462 address at a time, but can be configured not to do so, or to restrict multiple
1463 addresses to the same domain.
1464 .next
1465 Each local delivery to a file or a pipe runs in a separate process under a
1466 non-privileged uid, and these deliveries are run one at a time. Remote
1467 deliveries also run in separate processes, normally under a uid that is private
1468 to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
1469 run in parallel. The maximum number of simultaneous remote deliveries for any
1470 one message is set by the &%remote_max_parallel%& option.
1471 The order in which deliveries are done is not defined, except that all local
1472 deliveries happen before any remote deliveries.
1473 .next
1474 .cindex "queue runner"
1475 When it encounters a local delivery during a queue run, Exim checks its retry
1476 database to see if there has been a previous temporary delivery failure for the
1477 address before running the local transport. If there was a previous failure,
1478 Exim does not attempt a new delivery until the retry time for the address is
1479 reached. However, this happens only for delivery attempts that are part of a
1480 queue run. Local deliveries are always attempted when delivery immediately
1481 follows message reception, even if retry times are set for them. This makes for
1482 better behaviour if one particular message is causing problems (for example,
1483 causing quota overflow, or provoking an error in a filter file).
1484 .next
1485 .cindex "delivery" "retry in remote transports"
1486 Remote transports do their own retry handling, since an address may be
1487 deliverable to one of a number of hosts, each of which may have a different
1488 retry time. If there have been previous temporary failures and no host has
1489 reached its retry time, no delivery is attempted, whether in a queue run or
1490 not. See chapter &<<CHAPretry>>& for details of retry strategies.
1491 .next
1492 If there were any permanent errors, a bounce message is returned to an
1493 appropriate address (the sender in the common case), with details of the error
1494 for each failing address. Exim can be configured to send copies of bounce
1495 messages to other addresses.
1496 .next
1497 .cindex "delivery" "deferral"
1498 If one or more addresses suffered a temporary failure, the message is left on
1499 the queue, to be tried again later. Delivery of these addresses is said to be
1500 &'deferred'&.
1501 .next
1502 When all the recipient addresses have either been delivered or bounced,
1503 handling of the message is complete. The spool files and message log are
1504 deleted, though the message log can optionally be preserved if required.
1505 .endlist
1510 .section "Retry mechanism" "SECID19"
1511 .cindex "delivery" "retry mechanism"
1512 .cindex "retry" "description of mechanism"
1513 .cindex "queue runner"
1514 Exim's mechanism for retrying messages that fail to get delivered at the first
1515 attempt is the queue runner process. You must either run an Exim daemon that
1516 uses the &%-q%& option with a time interval to start queue runners at regular
1517 intervals, or use some other means (such as &'cron'&) to start them. If you do
1518 not arrange for queue runners to be run, messages that fail temporarily at the
1519 first attempt will remain on your queue for ever. A queue runner process works
1520 its way through the queue, one message at a time, trying each delivery that has
1521 passed its retry time.
1522 You can run several queue runners at once.
1524 Exim uses a set of configured rules to determine when next to retry the failing
1525 address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1526 should give up trying to deliver to the address, at which point it generates a
1527 bounce message. If no retry rules are set for a particular host, address, and
1528 error combination, no retries are attempted, and temporary errors are treated
1529 as permanent.
1533 .section "Temporary delivery failure" "SECID20"
1534 .cindex "delivery" "temporary failure"
1535 There are many reasons why a message may not be immediately deliverable to a
1536 particular address. Failure to connect to a remote machine (because it, or the
1537 connection to it, is down) is one of the most common. Temporary failures may be
1538 detected during routing as well as during the transport stage of delivery.
1539 Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1540 is on a file system where the user is over quota. Exim can be configured to
1541 impose its own quotas on local mailboxes; where system quotas are set they will
1542 also apply.
1544 .new
1545 If a host is unreachable for a period of time, a number of messages may be
1546 waiting for it by the time it recovers, and sending them in a single SMTP
1547 connection is clearly beneficial. Whenever a delivery to a remote host is
1548 deferred,
1549 .cindex "hints database"
1550 Exim makes a note in its hints database, and whenever a successful
1551 SMTP delivery has happened, it looks to see if any other messages are waiting
1552 for the same host. If any are found, they are sent over the same SMTP
1553 connection, subject to a configuration limit as to the maximum number in any
1554 one connection.
1555 .wen
1559 .section "Permanent delivery failure" "SECID21"
1560 .cindex "delivery" "permanent failure"
1561 .cindex "bounce message" "when generated"
1562 When a message cannot be delivered to some or all of its intended recipients, a
1563 bounce message is generated. Temporary delivery failures turn into permanent
1564 errors when their timeout expires. All the addresses that fail in a given
1565 delivery attempt are listed in a single message. If the original message has
1566 many recipients, it is possible for some addresses to fail in one delivery
1567 attempt and others to fail subsequently, giving rise to more than one bounce
1568 message. The wording of bounce messages can be customized by the administrator.
1569 See chapter &<<CHAPemsgcust>>& for details.
1571 .cindex "&'X-Failed-Recipients:'& header line"
1572 Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
1573 failed addresses, for the benefit of programs that try to analyse such messages
1574 automatically.
1576 .cindex "bounce message" "recipient of"
1577 A bounce message is normally sent to the sender of the original message, as
1578 obtained from the message's envelope. For incoming SMTP messages, this is the
1579 address given in the MAIL command. However, when an address is expanded via a
1580 forward or alias file, an alternative address can be specified for delivery
1581 failures of the generated addresses. For a mailing list expansion (see section
1582 &<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1583 of the list.
1587 .section "Failures to deliver bounce messages" "SECID22"
1588 .cindex "bounce message" "failure to deliver"
1589 If a bounce message (either locally generated or received from a remote host)
1590 itself suffers a permanent delivery failure, the message is left on the queue,
1591 but it is frozen, awaiting the attention of an administrator. There are options
1592 that can be used to make Exim discard such failed messages, or to keep them
1593 for only a short time (see &%timeout_frozen_after%& and
1594 &%ignore_bounce_errors_after%&).
1600 . ////////////////////////////////////////////////////////////////////////////
1601 . ////////////////////////////////////////////////////////////////////////////
1603 .chapter "Building and installing Exim" "CHID3"
1604 .scindex IIDbuex "building Exim"
1606 .section "Unpacking" "SECID23"
1607 Exim is distributed as a gzipped or bzipped tar file which, when unpacked,
1608 creates a directory with the name of the current release (for example,
1609 &_exim-&version;_&) into which the following files are placed:
1611 .table2 140pt
1612 .irow &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1613 .irow &_CHANGES_& "contains a reference to where changes are &&&
1614 documented"
1615 .irow &_LICENCE_& "the GNU General Public Licence"
1616 .irow &_Makefile_& "top-level make file"
1617 .irow &_NOTICE_& "conditions for the use of Exim"
1618 .irow &_README_& "list of files, directories and simple build &&&
1619 instructions"
1620 .endtable
1622 Other files whose names begin with &_README_& may also be present. The
1623 following subdirectories are created:
1625 .table2 140pt
1626 .irow &_Local_& "an empty directory for local configuration files"
1627 .irow &_OS_& "OS-specific files"
1628 .irow &_doc_& "documentation files"
1629 .irow &_exim_monitor_& "source files for the Exim monitor"
1630 .irow &_scripts_& "scripts used in the build process"
1631 .irow &_src_& "remaining source files"
1632 .irow &_util_& "independent utilities"
1633 .endtable
1635 The main utility programs are contained in the &_src_& directory, and are built
1636 with the Exim binary. The &_util_& directory contains a few optional scripts
1637 that may be useful to some sites.
1640 .section "Multiple machine architectures and operating systems" "SECID24"
1641 .cindex "building Exim" "multiple OS/architectures"
1642 The building process for Exim is arranged to make it easy to build binaries for
1643 a number of different architectures and operating systems from the same set of
1644 source files. Compilation does not take place in the &_src_& directory.
1645 Instead, a &'build directory'& is created for each architecture and operating
1646 system.
1647 .cindex "symbolic link" "to build directory"
1648 Symbolic links to the sources are installed in this directory, which is where
1649 the actual building takes place. In most cases, Exim can discover the machine
1650 architecture and operating system for itself, but the defaults can be
1651 overridden if necessary.
1654 .section "PCRE library" "SECTpcre"
1655 .cindex "PCRE library"
1656 Exim no longer has an embedded PCRE library as the vast majority of
1657 modern systems include PCRE as a system library, although you may need
1658 to install the PCRE or PCRE development package for your operating
1659 system. If your system has a normal PCRE installation the Exim build
1660 process will need no further configuration. If the library or the
1661 headers are in an unusual location you will need to set the PCRE_LIBS
1662 and INCLUDE directives appropriately. If your operating system has no
1663 PCRE support then you will need to obtain and build the current PCRE
1664 from &url(
1666 .section "DBM libraries" "SECTdb"
1667 .cindex "DBM libraries" "discussion of"
1668 .cindex "hints database" "DBM files used for"
1669 Even if you do not use any DBM files in your configuration, Exim still needs a
1670 DBM library in order to operate, because it uses indexed files for its hints
1671 databases. Unfortunately, there are a number of DBM libraries in existence, and
1672 different operating systems often have different ones installed.
1674 .cindex "Solaris" "DBM library for"
1675 .cindex "IRIX, DBM library for"
1676 .cindex "BSD, DBM library for"
1677 .cindex "Linux, DBM library for"
1678 If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1679 Linux distribution, the DBM configuration should happen automatically, and you
1680 may be able to ignore this section. Otherwise, you may have to learn more than
1681 you would like about DBM libraries from what follows.
1683 .cindex "&'ndbm'& DBM library"
1684 Licensed versions of Unix normally contain a library of DBM functions operating
1685 via the &'ndbm'& interface, and this is what Exim expects by default. Free
1686 versions of Unix seem to vary in what they contain as standard. In particular,
1687 some early versions of Linux have no default DBM library, and different
1688 distributors have chosen to bundle different libraries with their packaged
1689 versions. However, the more recent releases seem to have standardized on the
1690 Berkeley DB library.
1692 Different DBM libraries have different conventions for naming the files they
1693 use. When a program opens a file called &_dbmfile_&, there are several
1694 possibilities:
1696 .olist
1697 A traditional &'ndbm'& implementation, such as that supplied as part of
1698 Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1699 .next
1700 .cindex "&'gdbm'& DBM library"
1701 The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
1702 compatibility interface it makes two different hard links to it with names
1703 &_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
1704 file name is used unmodified.
1705 .next
1706 .cindex "Berkeley DB library"
1707 The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1708 operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1709 programmer exactly the same as the traditional &'ndbm'& implementation.
1710 .next
1711 If the Berkeley package is used in its native mode, it operates on a single
1712 file called &_dbmfile_&; the programmer's interface is somewhat different to
1713 the traditional &'ndbm'& interface.
1714 .next
1715 To complicate things further, there are several very different versions of the
1716 Berkeley DB package. Version 1.85 was stable for a very long time, releases
1717 2.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1718 numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
1719 versions of Berkeley DB can be obtained from
1720 &url(
1721 .next
1722 .cindex "&'tdb'& DBM library"
1723 Yet another DBM library, called &'tdb'&, is available from
1724 &url( It has its own interface, and also
1725 operates on a single file.
1726 .endlist
1728 .cindex "USE_DB"
1729 .cindex "DBM libraries" "configuration for building"
1730 Exim and its utilities can be compiled to use any of these interfaces. In order
1731 to use any version of the Berkeley DB package in native mode, you must set
1732 USE_DB in an appropriate configuration file (typically
1733 &_Local/Makefile_&). For example:
1734 .code
1735 USE_DB=yes
1736 .endd
1737 Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1738 error is diagnosed if you set more than one of these.
1740 At the lowest level, the build-time configuration sets none of these options,
1741 thereby assuming an interface of type (1). However, some operating system
1742 configuration files (for example, those for the BSD operating systems and
1743 Linux) assume type (4) by setting USE_DB as their default, and the
1744 configuration files for Cygwin set USE_GDBM. Anything you set in
1745 &_Local/Makefile_&, however, overrides these system defaults.
1747 As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1748 necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1749 in one of these lines:
1750 .code
1751 DBMLIB = -ldb
1752 DBMLIB = -ltdb
1753 .endd
1754 Settings like that will work if the DBM library is installed in the standard
1755 place. Sometimes it is not, and the library's header file may also not be in
1756 the default path. You may need to set INCLUDE to specify where the header
1757 file is, and to specify the path to the library more fully in DBMLIB, as in
1758 this example:
1759 .code
1760 INCLUDE=-I/usr/local/include/db-4.1
1761 DBMLIB=/usr/local/lib/db-4.1/libdb.a
1762 .endd
1763 There is further detailed discussion about the various DBM libraries in the
1764 file &_doc/dbm.discuss.txt_& in the Exim distribution.
1768 .section "Pre-building configuration" "SECID25"
1769 .cindex "building Exim" "pre-building configuration"
1770 .cindex "configuration for building Exim"
1771 .cindex "&_Local/Makefile_&"
1772 .cindex "&_src/EDITME_&"
1773 Before building Exim, a local configuration file that specifies options
1774 independent of any operating system has to be created with the name
1775 &_Local/Makefile_&. A template for this file is supplied as the file
1776 &_src/EDITME_&, and it contains full descriptions of all the option settings
1777 therein. These descriptions are therefore not repeated here. If you are
1778 building Exim for the first time, the simplest thing to do is to copy
1779 &_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
1781 There are three settings that you must supply, because Exim will not build
1782 without them. They are the location of the run time configuration file
1783 (CONFIGURE_FILE), the directory in which Exim binaries will be installed
1784 (BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1785 maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1786 a colon-separated list of file names; Exim uses the first of them that exists.
1788 There are a few other parameters that can be specified either at build time or
1789 at run time, to enable the same binary to be used on a number of different
1790 machines. However, if the locations of Exim's spool directory and log file
1791 directory (if not within the spool directory) are fixed, it is recommended that
1792 you specify them in &_Local/Makefile_& instead of at run time, so that errors
1793 detected early in Exim's execution (such as a malformed configuration file) can
1794 be logged.
1796 .cindex "content scanning" "specifying at build time"
1797 Exim's interfaces for calling virus and spam scanning software directly from
1798 access control lists are not compiled by default. If you want to include these
1799 facilities, you need to set
1800 .code
1802 .endd
1803 in your &_Local/Makefile_&. For details of the facilities themselves, see
1804 chapter &<<CHAPexiscan>>&.
1807 .cindex "&_Local/eximon.conf_&"
1808 .cindex "&_exim_monitor/EDITME_&"
1809 If you are going to build the Exim monitor, a similar configuration process is
1810 required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1811 your installation and saved under the name &_Local/eximon.conf_&. If you are
1812 happy with the default settings described in &_exim_monitor/EDITME_&,
1813 &_Local/eximon.conf_& can be empty, but it must exist.
1815 This is all the configuration that is needed in straightforward cases for known
1816 operating systems. However, the building process is set up so that it is easy
1817 to override options that are set by default or by operating-system-specific
1818 configuration files, for example to change the name of the C compiler, which
1819 defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1820 do this.
1824 .section "Support for iconv()" "SECID26"
1825 .cindex "&[iconv()]& support"
1826 .cindex "RFC 2047"
1827 The contents of header lines in messages may be encoded according to the rules
1828 described RFC 2047. This makes it possible to transmit characters that are not
1829 in the ASCII character set, and to label them as being in a particular
1830 character set. When Exim is inspecting header lines by means of the &%$h_%&
1831 mechanism, it decodes them, and translates them into a specified character set
1832 (default ISO-8859-1). The translation is possible only if the operating system
1833 supports the &[iconv()]& function.
1835 However, some of the operating systems that supply &[iconv()]& do not support
1836 very many conversions. The GNU &%libiconv%& library (available from
1837 &url( can be installed on such
1838 systems to remedy this deficiency, as well as on systems that do not supply
1839 &[iconv()]& at all. After installing &%libiconv%&, you should add
1840 .code
1841 HAVE_ICONV=yes
1842 .endd
1843 to your &_Local/Makefile_& and rebuild Exim.
1847 .section "Including TLS/SSL encryption support" "SECTinctlsssl"
1848 .cindex "TLS" "including support for TLS"
1849 .cindex "encryption" "including support for"
1850 .cindex "SUPPORT_TLS"
1851 .cindex "OpenSSL" "building Exim with"
1852 .cindex "GnuTLS" "building Exim with"
1853 Exim can be built to support encrypted SMTP connections, using the STARTTLS
1854 command as per RFC 2487. It can also support legacy clients that expect to
1855 start a TLS session immediately on connection to a non-standard port (see the
1856 &%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
1857 line option).
1859 If you want to build Exim with TLS support, you must first install either the
1860 OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1861 implementing SSL.
1863 If OpenSSL is installed, you should set
1864 .code
1865 SUPPORT_TLS=yes
1866 TLS_LIBS=-lssl -lcrypto
1867 .endd
1868 in &_Local/Makefile_&. You may also need to specify the locations of the
1869 OpenSSL library and include files. For example:
1870 .code
1871 SUPPORT_TLS=yes
1872 TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1873 TLS_INCLUDE=-I/usr/local/openssl/include/
1874 .endd
1875 .cindex "USE_GNUTLS"
1876 If GnuTLS is installed, you should set
1877 .code
1878 SUPPORT_TLS=yes
1879 USE_GNUTLS=yes
1880 TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1881 .endd
1882 in &_Local/Makefile_&, and again you may need to specify the locations of the
1883 library and include files. For example:
1884 .code
1885 SUPPORT_TLS=yes
1886 USE_GNUTLS=yes
1887 TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1888 TLS_INCLUDE=-I/usr/gnu/include
1889 .endd
1890 You do not need to set TLS_INCLUDE if the relevant directory is already
1891 specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1892 given in chapter &<<CHAPTLS>>&.
1897 .new
1898 .section "Use of tcpwrappers" "SECID27"
1900 .cindex "tcpwrappers, building Exim to support"
1901 .cindex "USE_TCP_WRAPPERS"
1903 .cindex "tcp_wrappers_daemon_name"
1904 Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1905 SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
1906 alternative to Exim's own checking facilities for installations that are
1907 already making use of &'tcpwrappers'& for other purposes. To do this, you
1908 should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1909 &_tcpd.h_& to be available at compile time, and also ensure that the library
1910 &_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1911 EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1912 you might have
1913 .code
1915 CFLAGS=-O -I/usr/local/include
1916 EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1917 .endd
1918 in &_Local/Makefile_&. The daemon name to use in the &'tcpwrappers'& control
1919 files is &"exim"&. For example, the line
1920 .code
1921 exim : LOCAL 192.168.1. .friendly.domain.example
1922 .endd
1923 in your &_/etc/hosts.allow_& file allows connections from the local host, from
1924 the subnet, and from all hosts in &'friendly.domain.example'&.
1925 All other connections are denied. The daemon name used by &'tcpwrappers'&
1926 can be changed at build time by setting TCP_WRAPPERS_DAEMON_NAME in
1927 in &_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the
1928 configure file. Consult the &'tcpwrappers'& documentation for
1929 further details.
1930 .wen
1933 .section "Including support for IPv6" "SECID28"
1934 .cindex "IPv6" "including support for"
1935 Exim contains code for use on systems that have IPv6 support. Setting
1936 &`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
1937 it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1938 where the IPv6 support is not fully integrated into the normal include and
1939 library files.
1941 Two different types of DNS record for handling IPv6 addresses have been
1942 defined. AAAA records (analogous to A records for IPv4) are in use, and are
1943 currently seen as the mainstream. Another record type called A6 was proposed
1944 as better than AAAA because it had more flexibility. However, it was felt to be
1945 over-complex, and its status was reduced to &"experimental"&. It is not known
1946 if anyone is actually using A6 records. Exim has support for A6 records, but
1947 this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
1948 support has not been tested for some time.
1952 .new
1953 .section "Dynamically loaded lookup module support" "SECTdynamicmodules"
1954 .cindex "lookup modules"
1955 .cindex "dynamic modules"
1956 .cindex ".so building"
1957 On some platforms, Exim supports not compiling all lookup types directly into
1958 the main binary, instead putting some into external modules which can be loaded
1959 on demand.
1960 This permits packagers to build Exim with support for lookups with extensive
1961 library dependencies without requiring all users to install all of those
1962 dependencies.
1963 Most, but not all, lookup types can be built this way.
1965 Set &`LOOKUP_MODULE_DIR`& to the directory into which the modules will be
1966 installed; Exim will only load modules from that directory, as a security
1967 measure. You will need to set &`CFLAGS_DYNAMIC`& if not already defined
1968 for your OS; see &_OS/Makefile-Linux_& for an example.
1969 Some other requirements for adjusting &`EXTRALIBS`& may also be necessary,
1970 see &_src/EDITME_& for details.
1972 Then, for each module to be loaded dynamically, define the relevant
1973 &`LOOKUP_`&<&'lookup_type'&> flags to have the value "2" instead of "yes".
1974 For example, this will build in lsearch but load sqlite and mysql support
1975 on demand:
1976 .code
1980 .endd
1981 .wen
1983 .section "The building process" "SECID29"
1984 .cindex "build directory"
1985 Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
1986 created, run &'make'& at the top level. It determines the architecture and
1987 operating system types, and creates a build directory if one does not exist.
1988 For example, on a Sun system running Solaris 8, the directory
1989 &_build-SunOS5-5.8-sparc_& is created.
1990 .cindex "symbolic link" "to source files"
1991 Symbolic links to relevant source files are installed in the build directory.
1993 &*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
1994 building process fails if it is set.
1996 If this is the first time &'make'& has been run, it calls a script that builds
1997 a make file inside the build directory, using the configuration files from the
1998 &_Local_& directory. The new make file is then passed to another instance of
1999 &'make'&. This does the real work, building a number of utility scripts, and
2000 then compiling and linking the binaries for the Exim monitor (if configured), a
2001 number of utility programs, and finally Exim itself. The command &`make
2002 makefile`& can be used to force a rebuild of the make file in the build
2003 directory, should this ever be necessary.
2005 If you have problems building Exim, check for any comments there may be in the
2006 &_README_& file concerning your operating system, and also take a look at the
2007 FAQ, where some common problems are covered.
2011 .section 'Output from &"make"&' "SECID283"
2012 The output produced by the &'make'& process for compile lines is often very
2013 unreadable, because these lines can be very long. For this reason, the normal
2014 output is suppressed by default, and instead output similar to that which
2015 appears when compiling the 2.6 Linux kernel is generated: just a short line for
2016 each module that is being compiled or linked. However, it is still possible to
2017 get the full output, by calling &'make'& like this:
2018 .code
2019 FULLECHO='' make -e
2020 .endd
2021 The value of FULLECHO defaults to &"@"&, the flag character that suppresses
2022 command reflection in &'make'&. When you ask for the full output, it is
2023 given in addition to the short output.
2027 .section "Overriding build-time options for Exim" "SECToverride"
2028 .cindex "build-time options, overriding"
2029 The main make file that is created at the beginning of the building process
2030 consists of the concatenation of a number of files which set configuration
2031 values, followed by a fixed set of &'make'& instructions. If a value is set
2032 more than once, the last setting overrides any previous ones. This provides a
2033 convenient way of overriding defaults. The files that are concatenated are, in
2034 order:
2035 .display
2036 &_OS/Makefile-Default_&
2037 &_OS/Makefile-_&<&'ostype'&>
2038 &_Local/Makefile_&
2039 &_Local/Makefile-_&<&'ostype'&>
2040 &_Local/Makefile-_&<&'archtype'&>
2041 &_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
2042 &_OS/Makefile-Base_&
2043 .endd
2044 .cindex "&_Local/Makefile_&"
2045 .cindex "building Exim" "operating system type"
2046 .cindex "building Exim" "architecture type"
2047 where <&'ostype'&> is the operating system type and <&'archtype'&> is the
2048 architecture type. &_Local/Makefile_& is required to exist, and the building
2049 process fails if it is absent. The other three &_Local_& files are optional,
2050 and are often not needed.
2052 The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
2053 called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
2054 the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
2055 values are used, thereby providing a means of forcing particular settings.
2056 Otherwise, the scripts try to get values from the &%uname%& command. If this
2057 fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
2058 of &'ad hoc'& transformations are then applied, to produce the standard names
2059 that Exim expects. You can run these scripts directly from the shell in order
2060 to find out what values are being used on your system.
2063 &_OS/Makefile-Default_& contains comments about the variables that are set
2064 therein. Some (but not all) are mentioned below. If there is something that
2065 needs changing, review the contents of this file and the contents of the make
2066 file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
2067 default values are.
2070 .cindex "building Exim" "overriding default settings"
2071 If you need to change any of the values that are set in &_OS/Makefile-Default_&
2072 or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
2073 need to change the original files. Instead, you should make the changes by
2074 putting the new values in an appropriate &_Local_& file. For example,
2075 .cindex "Tru64-Unix build-time settings"
2076 when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2077 formerly DEC-OSF1) operating system, it is necessary to specify that the C
2078 compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2079 called with the option &%-std1%&, to make it recognize some of the features of
2080 Standard C that Exim uses. (Most other compilers recognize Standard C by
2081 default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
2082 containing the lines
2083 .code
2084 CC=cc
2085 CFLAGS=-std1
2086 .endd
2087 If you are compiling for just one operating system, it may be easier to put
2088 these lines directly into &_Local/Makefile_&.
2090 Keeping all your local configuration settings separate from the distributed
2091 files makes it easy to transfer them to new versions of Exim simply by copying
2092 the contents of the &_Local_& directory.
2095 .cindex "NIS lookup type" "including support for"
2096 .cindex "NIS+ lookup type" "including support for"
2097 .cindex "LDAP" "including support for"
2098 .cindex "lookup" "inclusion in binary"
2099 Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2100 lookup, but not all systems have these components installed, so the default is
2101 not to include the relevant code in the binary. All the different kinds of file
2102 and database lookup that Exim supports are implemented as separate code modules
2103 which are included only if the relevant compile-time options are set. In the
2104 case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2105 .code
2106 LOOKUP_LDAP=yes
2107 LOOKUP_NIS=yes
2109 .endd
2110 and similar settings apply to the other lookup types. They are all listed in
2111 &_src/EDITME_&. In many cases the relevant include files and interface
2112 libraries need to be installed before compiling Exim.
2113 .cindex "cdb" "including support for"
2114 However, there are some optional lookup types (such as cdb) for which
2115 the code is entirely contained within Exim, and no external include
2116 files or libraries are required. When a lookup type is not included in the
2117 binary, attempts to configure Exim to use it cause run time configuration
2118 errors.
2120 .cindex "Perl" "including support for"
2121 Exim can be linked with an embedded Perl interpreter, allowing Perl
2122 subroutines to be called during string expansion. To enable this facility,
2123 .code
2124 EXIM_PERL=perl.o
2125 .endd
2126 must be defined in &_Local/Makefile_&. Details of this facility are given in
2127 chapter &<<CHAPperl>>&.
2129 .cindex "X11 libraries, location of"
2130 The location of the X11 libraries is something that varies a lot between
2131 operating systems, and there may be different versions of X11 to cope
2132 with. Exim itself makes no use of X11, but if you are compiling the Exim
2133 monitor, the X11 libraries must be available.
2134 The following three variables are set in &_OS/Makefile-Default_&:
2135 .code
2136 X11=/usr/X11R6
2137 XINCLUDE=-I$(X11)/include
2138 XLFLAGS=-L$(X11)/lib
2139 .endd
2140 These are overridden in some of the operating-system configuration files. For
2141 example, in &_OS/Makefile-SunOS5_& there is
2142 .code
2143 X11=/usr/openwin
2144 XINCLUDE=-I$(X11)/include
2145 XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2146 .endd
2147 If you need to override the default setting for your operating system, place a
2148 definition of all three of these variables into your
2149 &_Local/Makefile-<ostype>_& file.
2151 .cindex "EXTRALIBS"
2152 If you need to add any extra libraries to the link steps, these can be put in a
2153 variable called EXTRALIBS, which appears in all the link commands, but by
2154 default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2155 command for linking the main Exim binary, and not for any associated utilities.
2157 .cindex "DBM libraries" "configuration for building"
2158 There is also DBMLIB, which appears in the link commands for binaries that
2159 use DBM functions (see also section &<<SECTdb>>&). Finally, there is
2160 EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2161 binary, and which can be used, for example, to include additional X11
2162 libraries.
2164 .cindex "configuration file" "editing"
2165 The make file copes with rebuilding Exim correctly if any of the configuration
2166 files are edited. However, if an optional configuration file is deleted, it is
2167 necessary to touch the associated non-optional file (that is,
2168 &_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
2171 .section "OS-specific header files" "SECID30"
2172 .cindex "&_os.h_&"
2173 .cindex "building Exim" "OS-specific C header files"
2174 The &_OS_& directory contains a number of files with names of the form
2175 &_os.h-<ostype>_&. These are system-specific C header files that should not
2176 normally need to be changed. There is a list of macro settings that are
2177 recognized in the file &_OS/os.configuring_&, which should be consulted if you
2178 are porting Exim to a new operating system.
2182 .section "Overriding build-time options for the monitor" "SECID31"
2183 .cindex "building Eximon"
2184 A similar process is used for overriding things when building the Exim monitor,
2185 where the files that are involved are
2186 .display
2187 &_OS/eximon.conf-Default_&
2188 &_OS/eximon.conf-_&<&'ostype'&>
2189 &_Local/eximon.conf_&
2190 &_Local/eximon.conf-_&<&'ostype'&>
2191 &_Local/eximon.conf-_&<&'archtype'&>
2192 &_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2193 .endd
2194 .cindex "&_Local/eximon.conf_&"
2195 As with Exim itself, the final three files need not exist, and in this case the
2196 &_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2197 &_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
2198 variables of the same name, preceded by EXIMON_. For example, setting
2199 EXIMON_LOG_DEPTH in the environment overrides the value of
2200 LOG_DEPTH at run time.
2201 .ecindex IIDbuex
2204 .section "Installing Exim binaries and scripts" "SECID32"
2205 .cindex "installing Exim"
2206 .cindex "BIN_DIRECTORY"
2207 The command &`make install`& runs the &(exim_install)& script with no
2208 arguments. The script copies binaries and utility scripts into the directory
2209 whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2210 .cindex "setuid" "installing Exim with"
2211 The install script copies files only if they are newer than the files they are
2212 going to replace. The Exim binary is required to be owned by root and have the
2213 &'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2214 install`& as root so that it can set up the Exim binary in this way. However, in
2215 some special situations (for example, if a host is doing no local deliveries)
2216 it may be possible to run Exim without making the binary setuid root (see
2217 chapter &<<CHAPsecurity>>& for details).
2219 .cindex "CONFIGURE_FILE"
2220 Exim's run time configuration file is named by the CONFIGURE_FILE setting
2221 in &_Local/Makefile_&. If this names a single file, and the file does not
2222 exist, the default configuration file &_src/configure.default_& is copied there
2223 by the installation script. If a run time configuration file already exists, it
2224 is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2225 alternative files, no default is installed.
2227 .cindex "system aliases file"
2228 .cindex "&_/etc/aliases_&"
2229 One change is made to the default configuration file when it is installed: the
2230 default configuration contains a router that references a system aliases file.
2231 The path to this file is set to the value specified by
2232 SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
2233 If the system aliases file does not exist, the installation script creates it,
2234 and outputs a comment to the user.
2236 The created file contains no aliases, but it does contain comments about the
2237 aliases a site should normally have. Mail aliases have traditionally been
2238 kept in &_/etc/aliases_&. However, some operating systems are now using
2239 &_/etc/mail/aliases_&. You should check if yours is one of these, and change
2240 Exim's configuration if necessary.
2242 The default configuration uses the local host's name as the only local domain,
2243 and is set up to do local deliveries into the shared directory &_/var/mail_&,
2244 running as the local user. System aliases and &_.forward_& files in users' home
2245 directories are supported, but no NIS or NIS+ support is configured. Domains
2246 other than the name of the local host are routed using the DNS, with delivery
2247 over SMTP.
2249 It is possible to install Exim for special purposes (such as building a binary
2250 distribution) in a private part of the file system. You can do this by a
2251 command such as
2252 .code
2253 make DESTDIR=/some/directory/ install
2254 .endd
2255 This has the effect of pre-pending the specified directory to all the file
2256 paths, except the name of the system aliases file that appears in the default
2257 configuration. (If a default alias file is created, its name &'is'& modified.)
2258 For backwards compatibility, ROOT is used if DESTDIR is not set,
2259 but this usage is deprecated.
2261 .cindex "installing Exim" "what is not installed"
2262 Running &'make install'& does not copy the Exim 4 conversion script
2263 &'convert4r4'&. You will probably run this only once if you are
2264 upgrading from Exim 3. None of the documentation files in the &_doc_&
2265 directory are copied, except for the info files when you have set
2266 INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
2268 For the utility programs, old versions are renamed by adding the suffix &_.O_&
2269 to their names. The Exim binary itself, however, is handled differently. It is
2270 installed under a name that includes the version number and the compile number,
2271 for example &_exim-&version;-1_&. The script then arranges for a symbolic link
2272 called &_exim_& to point to the binary. If you are updating a previous version
2273 of Exim, the script takes care to ensure that the name &_exim_& is never absent
2274 from the directory (as seen by other processes).
2276 .cindex "installing Exim" "testing the script"
2277 If you want to see what the &'make install'& will do before running it for
2278 real, you can pass the &%-n%& option to the installation script by this
2279 command:
2280 .code
2281 make INSTALL_ARG=-n install
2282 .endd
2283 The contents of the variable INSTALL_ARG are passed to the installation
2284 script. You do not need to be root to run this test. Alternatively, you can run
2285 the installation script directly, but this must be from within the build
2286 directory. For example, from the top-level Exim directory you could use this
2287 command:
2288 .code
2289 (cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2290 .endd
2291 .cindex "installing Exim" "install script options"
2292 There are two other options that can be supplied to the installation script.
2294 .ilist
2295 &%-no_chown%& bypasses the call to change the owner of the installed binary
2296 to root, and the call to make it a setuid binary.
2297 .next
2298 &%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
2299 installed binary.
2300 .endlist
2302 INSTALL_ARG can be used to pass these options to the script. For example:
2303 .code
2304 make INSTALL_ARG=-no_symlink install
2305 .endd
2306 The installation script can also be given arguments specifying which files are
2307 to be copied. For example, to install just the Exim binary, and nothing else,
2308 without creating the symbolic link, you could use:
2309 .code
2310 make INSTALL_ARG='-no_symlink exim' install
2311 .endd
2315 .section "Installing info documentation" "SECTinsinfdoc"
2316 .cindex "installing Exim" "&'info'& documentation"
2317 Not all systems use the GNU &'info'& system for documentation, and for this
2318 reason, the Texinfo source of Exim's documentation is not included in the main
2319 distribution. Instead it is available separately from the ftp site (see section
2320 &<<SECTavail>>&).
2322 If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2323 source of the documentation is found in the source tree, running &`make
2324 install`& automatically builds the info files and installs them.
2328 .section "Setting up the spool directory" "SECID33"
2329 .cindex "spool directory" "creating"
2330 When it starts up, Exim tries to create its spool directory if it does not
2331 exist. The Exim uid and gid are used for the owner and group of the spool
2332 directory. Sub-directories are automatically created in the spool directory as
2333 necessary.
2338 .section "Testing" "SECID34"
2339 .cindex "testing" "installation"
2340 Having installed Exim, you can check that the run time configuration file is
2341 syntactically valid by running the following command, which assumes that the
2342 Exim binary directory is within your PATH environment variable:
2343 .code
2344 exim -bV
2345 .endd
2346 If there are any errors in the configuration file, Exim outputs error messages.
2347 Otherwise it outputs the version number and build date,
2348 the DBM library that is being used, and information about which drivers and
2349 other optional code modules are included in the binary.
2350 Some simple routing tests can be done by using the address testing option. For
2351 example,
2352 .display
2353 &`exim -bt`& <&'local username'&>
2354 .endd
2355 should verify that it recognizes a local mailbox, and
2356 .display
2357 &`exim -bt`& <&'remote address'&>
2358 .endd
2359 a remote one. Then try getting it to deliver mail, both locally and remotely.
2360 This can be done by passing messages directly to Exim, without going through a
2361 user agent. For example:
2362 .code
2363 exim -v postmaster@your.domain.example
2364 From: user@your.domain.example
2365 To: postmaster@your.domain.example
2366 Subject: Testing Exim
2368 This is a test message.
2369 ^D
2370 .endd
2371 The &%-v%& option causes Exim to output some verification of what it is doing.
2372 In this case you should see copies of three log lines, one for the message's
2373 arrival, one for its delivery, and one containing &"Completed"&.
2375 .cindex "delivery" "problems with"
2376 If you encounter problems, look at Exim's log files (&'mainlog'& and
2377 &'paniclog'&) to see if there is any relevant information there. Another source
2378 of information is running Exim with debugging turned on, by specifying the
2379 &%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
2380 with debugging turned on by a command of the form
2381 .display
2382 &`exim -d -M`& <&'exim-message-id'&>
2383 .endd
2384 You must be root or an &"admin user"& in order to do this. The &%-d%& option
2385 produces rather a lot of output, but you can cut this down to specific areas.
2386 For example, if you use &%-d-all+route%& only the debugging information
2387 relevant to routing is included. (See the &%-d%& option in chapter
2388 &<<CHAPcommandline>>& for more details.)
2390 .cindex '&"sticky"& bit'
2391 .cindex "lock files"
2392 One specific problem that has shown up on some sites is the inability to do
2393 local deliveries into a shared mailbox directory, because it does not have the
2394 &"sticky bit"& set on it. By default, Exim tries to create a lock file before
2395 writing to a mailbox file, and if it cannot create the lock file, the delivery
2396 is deferred. You can get round this either by setting the &"sticky bit"& on the
2397 directory, or by setting a specific group for local deliveries and allowing
2398 that group to create files in the directory (see the comments above the
2399 &(local_delivery)& transport in the default configuration file). Another
2400 approach is to configure Exim not to use lock files, but just to rely on
2401 &[fcntl()]& locking instead. However, you should do this only if all user
2402 agents also use &[fcntl()]& locking. For further discussion of locking issues,
2403 see chapter &<<CHAPappendfile>>&.
2405 One thing that cannot be tested on a system that is already running an MTA is
2406 the receipt of incoming SMTP mail on the standard SMTP port. However, the
2407 &%-oX%& option can be used to run an Exim daemon that listens on some other
2408 port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2409 &'exim_checkaccess'& utility can be used to check out policy controls on
2410 incoming SMTP mail.
2412 Testing a new version on a system that is already running Exim can most easily
2413 be done by building a binary with a different CONFIGURE_FILE setting. From
2414 within the run time configuration, all other file and directory names
2415 that Exim uses can be altered, in order to keep it entirely clear of the
2416 production version.
2419 .section "Replacing another MTA with Exim" "SECID35"
2420 .cindex "replacing another MTA"
2421 Building and installing Exim for the first time does not of itself put it in
2422 general use. The name by which the system's MTA is called by mail user agents
2423 is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2424 operating system), and it is necessary to make this name point to the &'exim'&
2425 binary in order to get the user agents to pass messages to Exim. This is
2426 normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2427 or &_/usr/lib/sendmail_&
2428 .cindex "symbolic link" "to &'exim'& binary"
2429 a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
2430 privilege and executable status from the old MTA. It is then necessary to stop
2431 and restart the mailer daemon, if one is running.
2433 .cindex "FreeBSD, MTA indirection"
2434 .cindex "&_/etc/mail/mailer.conf_&"
2435 Some operating systems have introduced alternative ways of switching MTAs. For
2436 example, if you are running FreeBSD, you need to edit the file
2437 &_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
2438 described. A typical example of the contents of this file for running Exim is
2439 as follows:
2440 .code
2441 sendmail /usr/exim/bin/exim
2442 send-mail /usr/exim/bin/exim
2443 mailq /usr/exim/bin/exim -bp
2444 newaliases /usr/bin/true
2445 .endd
2446 Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2447 your Exim installation is &"live"&. Check it by sending a message from your
2448 favourite user agent.
2450 You should consider what to tell your users about the change of MTA. Exim may
2451 have different capabilities to what was previously running, and there are
2452 various operational differences such as the text of messages produced by
2453 command line options and in bounce messages. If you allow your users to make
2454 use of Exim's filtering capabilities, you should make the document entitled
2455 &'Exim's interface to mail filtering'& available to them.
2459 .section "Upgrading Exim" "SECID36"
2460 .cindex "upgrading Exim"
2461 If you are already running Exim on your host, building and installing a new
2462 version automatically makes it available to MUAs, or any other programs that
2463 call the MTA directly. However, if you are running an Exim daemon, you do need
2464 to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2465 new binary. You do not need to stop processing mail in order to install a new
2466 version of Exim. The install script does not modify an existing runtime
2467 configuration file.
2472 .section "Stopping the Exim daemon on Solaris" "SECID37"
2473 .cindex "Solaris" "stopping Exim on"
2474 The standard command for stopping the mailer daemon on Solaris is
2475 .code
2476 /etc/init.d/sendmail stop
2477 .endd
2478 If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2479 fails to stop Exim because it uses the command &'ps -e'& and greps the output
2480 for the text &"sendmail"&; this is not present because the actual program name
2481 (that is, &"exim"&) is given by the &'ps'& command with these options. A
2482 solution is to replace the line that finds the process id with something like
2483 .code
2484 pid=`cat /var/spool/exim/`
2485 .endd
2486 to obtain the daemon's pid directly from the file that Exim saves it in.
2488 Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
2489 still be received from local processes, and if automatic delivery is configured
2490 (the normal case), deliveries will still occur.
2495 . ////////////////////////////////////////////////////////////////////////////
2496 . ////////////////////////////////////////////////////////////////////////////
2498 .chapter "The Exim command line" "CHAPcommandline"
2499 .scindex IIDclo1 "command line" "options"
2500 .scindex IIDclo2 "options" "command line"
2501 Exim's command line takes the standard Unix form of a sequence of options,
2502 each starting with a hyphen character, followed by a number of arguments. The
2503 options are compatible with the main options of Sendmail, and there are also
2504 some additional options, some of which are compatible with Smail 3. Certain
2505 combinations of options do not make sense, and provoke an error if used.
2506 The form of the arguments depends on which options are set.
2509 .section "Setting options by program name" "SECID38"
2510 .cindex "&'mailq'&"
2511 If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
2512 were present before any other options.
2513 The &%-bp%& option requests a listing of the contents of the mail queue on the
2514 standard output.
2515 This feature is for compatibility with some systems that contain a command of
2516 that name in one of the standard libraries, symbolically linked to
2517 &_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2519 .cindex "&'rsmtp'&"
2520 If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2521 were present before any other options, for compatibility with Smail. The
2522 &%-bS%& option is used for reading in a number of messages in batched SMTP
2523 format.
2525 .cindex "&'rmail'&"
2526 If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2527 &%-oee%& options were present before any other options, for compatibility with
2528 Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2530 .cindex "&'runq'&"
2531 .cindex "queue runner"
2532 If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2533 were present before any other options, for compatibility with Smail. The &%-q%&
2534 option causes a single queue runner process to be started.
2536 .cindex "&'newaliases'&"
2537 .cindex "alias file" "building"
2538 .cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2539 If Exim is called under the name &'newaliases'& it behaves as if the option
2540 &%-bi%& were present before any other options, for compatibility with Sendmail.
2541 This option is used for rebuilding Sendmail's alias file. Exim does not have
2542 the concept of a single alias file, but can be configured to run a given
2543 command if called with the &%-bi%& option.
2546 .section "Trusted and admin users" "SECTtrustedadmin"
2547 Some Exim options are available only to &'trusted users'& and others are
2548 available only to &'admin users'&. In the description below, the phrases &"Exim
2549 user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2550 EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2551 &%exim_group%& options. These do not necessarily have to use the name &"exim"&.
2553 .ilist
2554 .cindex "trusted users" "definition of"
2555 .cindex "user" "trusted definition of"
2556 The trusted users are root, the Exim user, any user listed in the
2557 &%trusted_users%& configuration option, and any user whose current group or any
2558 supplementary group is one of those listed in the &%trusted_groups%&
2559 configuration option. Note that the Exim group is not automatically trusted.
2561 .cindex '&"From"& line'
2562 .cindex "envelope sender"
2563 Trusted users are always permitted to use the &%-f%& option or a leading
2564 &"From&~"& line to specify the envelope sender of a message that is passed to
2565 Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2566 See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2567 users to set envelope senders.
2569 .cindex "&'From:'& header line"
2570 .cindex "&'Sender:'& header line"
2571 For a trusted user, there is never any check on the contents of the &'From:'&
2572 header line, and a &'Sender:'& line is never added. Furthermore, any existing
2573 &'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2575 Trusted users may also specify a host name, host address, interface address,
2576 protocol name, ident value, and authentication data when submitting a message
2577 locally. Thus, they are able to insert messages into Exim's queue locally that
2578 have the characteristics of messages received from a remote host. Untrusted
2579 users may in some circumstances use &%-f%&, but can never set the other values
2580 that are available to trusted users.
2581 .next
2582 .cindex "user" "admin definition of"
2583 .cindex "admin user" "definition of"
2584 The admin users are root, the Exim user, and any user that is a member of the
2585 Exim group or of any group listed in the &%admin_groups%& configuration option.
2586 The current group does not have to be one of these groups.
2588 Admin users are permitted to list the queue, and to carry out certain
2589 operations on messages, for example, to force delivery failures. It is also
2590 necessary to be an admin user in order to see the full information provided by
2591 the Exim monitor, and full debugging output.
2593 By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2594 Exim to attempt delivery of messages on its queue is restricted to admin users.
2595 However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2596 option false (that is, specifying &%no_prod_requires_admin%&).
2598 Similarly, the use of the &%-bp%& option to list all the messages in the queue
2599 is restricted to admin users unless &%queue_list_requires_admin%& is set
2600 false.
2601 .endlist
2604 &*Warning*&: If you configure your system so that admin users are able to
2605 edit Exim's configuration file, you are giving those users an easy way of
2606 getting root. There is further discussion of this issue at the start of chapter
2607 &<<CHAPconf>>&.
2612 .section "Command line options" "SECID39"
2613 Exim's command line options are described in alphabetical order below. If none
2614 of the options that specifies a specific action (such as starting the daemon or
2615 a queue runner, or testing an address, or receiving a message in a specific
2616 format, or listing the queue) are present, and there is at least one argument
2617 on the command line, &%-bm%& (accept a local message on the standard input,
2618 with the arguments specifying the recipients) is assumed. Otherwise, Exim
2619 outputs a brief message about itself and exits.
2621 . ////////////////////////////////////////////////////////////////////////////
2622 . Insert a stylized XML comment here, to identify the start of the command line
2623 . options. This is for the benefit of the Perl script that automatically
2624 . creates a man page for the options.
2625 . ////////////////////////////////////////////////////////////////////////////
2627 .literal xml
2628 <!-- === Start of command line options === -->
2629 .literal off
2632 .vlist
2633 .vitem &%--%&
2634 .oindex "--"
2635 .cindex "options" "command line; terminating"
2636 This is a pseudo-option whose only purpose is to terminate the options and
2637 therefore to cause subsequent command line items to be treated as arguments
2638 rather than options, even if they begin with hyphens.
2640 .vitem &%--help%&
2641 .oindex "&%--help%&"
2642 This option causes Exim to output a few sentences stating what it is.
2643 The same output is generated if the Exim binary is called with no options and
2644 no arguments.
2646 .new
2647 .vitem &%--version%&
2648 .oindex "&%--version%&"
2649 This option is an alias for &%-bV%& and causes version information to be
2650 displayed.
2651 .wen
2653 .vitem &%-B%&<&'type'&>
2654 .oindex "&%-B%&"
2655 .cindex "8-bit characters"
2656 .cindex "Sendmail compatibility" "8-bit characters"
2657 This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2658 clean; it ignores this option.
2660 .vitem &%-bd%&
2661 .oindex "&%-bd%&"
2662 .cindex "daemon"
2663 .cindex "SMTP" "listener"
2664 .cindex "queue runner"
2665 This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
2666 the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2667 that the daemon should also initiate periodic queue runs.
2669 The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2670 (debugging) or &%-v%& (verifying) options are set, the daemon does not
2671 disconnect from the controlling terminal. When running this way, it can be
2672 stopped by pressing ctrl-C.
2674 By default, Exim listens for incoming connections to the standard SMTP port on
2675 all the host's running interfaces. However, it is possible to listen on other
2676 ports, on multiple ports, and only on specific interfaces. Chapter
2677 &<<CHAPinterfaces>>& contains a description of the options that control this.
2679 When a listening daemon
2680 .cindex "daemon" "process id (pid)"
2681 .cindex "pid (process id)" "of daemon"
2682 is started without the use of &%-oX%& (that is, without overriding the normal
2683 configuration), it writes its process id to a file called &_exim-daemon.pid_&
2684 in Exim's spool directory. This location can be overridden by setting
2685 PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
2686 running as root.
2688 When &%-oX%& is used on the command line to start a listening daemon, the
2689 process id is not written to the normal pid file path. However, &%-oP%& can be
2690 used to specify a path on the command line if a pid file is required.
2692 The SIGHUP signal
2693 .cindex "SIGHUP"
2694 .cindex "daemon" "restarting"
2695 can be used to cause the daemon to re-execute itself. This should be done
2696 whenever Exim's configuration file, or any file that is incorporated into it by
2697 means of the &%.include%& facility, is changed, and also whenever a new version
2698 of Exim is installed. It is not necessary to do this when other files that are
2699 referenced from the configuration (for example, alias files) are changed,
2700 because these are reread each time they are used.
2702 .vitem &%-bdf%&
2703 .oindex "&%-bdf%&"
2704 This option has the same effect as &%-bd%& except that it never disconnects
2705 from the controlling terminal, even when no debugging is specified.
2707 .vitem &%-be%&
2708 .oindex "&%-be%&"
2709 .cindex "testing" "string expansion"
2710 .cindex "expansion" "testing"
2711 Run Exim in expansion testing mode. Exim discards its root privilege, to
2712 prevent ordinary users from using this mode to read otherwise inaccessible
2713 files. If no arguments are given, Exim runs interactively, prompting for lines
2714 of data. Otherwise, it processes each argument in turn.
2716 If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2717 to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2718 used without command line arguments. If successful, it uses the &[readline()]&
2719 function, which provides extensive line-editing facilities, for reading the
2720 test data. A line history is supported.
2722 Long expansion expressions can be split over several lines by using backslash
2723 continuations. As in Exim's run time configuration, white space at the start of
2724 continuation lines is ignored. Each argument or data line is passed through the
2725 string expansion mechanism, and the result is output. Variable values from the
2726 configuration file (for example, &$qualify_domain$&) are available, but no
2727 message-specific values (such as &$sender_domain$&) are set, because no message
2728 is being processed (but see &%-bem%& and &%-Mset%&).
2730 &*Note*&: If you use this mechanism to test lookups, and you change the data
2731 files or databases you are using, you must exit and restart Exim before trying
2732 the same lookup again. Otherwise, because each Exim process caches the results
2733 of lookups, you will just get the same result as before.
2735 .vitem &%-bem%&&~<&'filename'&>
2736 .oindex "&%-bem%&"
2737 .cindex "testing" "string expansion"
2738 .cindex "expansion" "testing"
2739 This option operates like &%-be%& except that it must be followed by the name
2740 of a file. For example:
2741 .code
2742 exim -bem /tmp/testmessage
2743 .endd
2744 The file is read as a message (as if receiving a locally-submitted non-SMTP
2745 message) before any of the test expansions are done. Thus, message-specific
2746 variables such as &$message_size$& and &$header_from:$& are available. However,
2747 no &'Received:'& header is added to the message. If the &%-t%& option is set,
2748 recipients are read from the headers in the normal way, and are shown in the
2749 &$recipients$& variable. Note that recipients cannot be given on the command
2750 line, because further arguments are taken as strings to expand (just like
2751 &%-be%&).
2753 .vitem &%-bF%&&~<&'filename'&>
2754 .oindex "&%-bF%&"
2755 .cindex "system filter" "testing"
2756 .cindex "testing" "system filter"
2757 This option is the same as &%-bf%& except that it assumes that the filter being
2758 tested is a system filter. The additional commands that are available only in
2759 system filters are recognized.
2761 .vitem &%-bf%&&~<&'filename'&>
2762 .oindex "&%-bf%&"
2763 .cindex "filter" "testing"
2764 .cindex "testing" "filter file"
2765 .cindex "forward file" "testing"
2766 .cindex "testing" "forward file"
2767 .cindex "Sieve filter" "testing"
2768 This option runs Exim in user filter testing mode; the file is the filter file
2769 to be tested, and a test message must be supplied on the standard input. If
2770 there are no message-dependent tests in the filter, an empty file can be
2771 supplied.
2773 If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2774 can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2775 filter and a user filter in the same run. For example:
2776 .code
2777 exim -bF /system/filter -bf /user/filter </test/message
2778 .endd
2779 This is helpful when the system filter adds header lines or sets filter
2780 variables that are used by the user filter.
2782 If the test filter file does not begin with one of the special lines
2783 .code
2784 # Exim filter
2785 # Sieve filter
2786 .endd
2787 it is taken to be a normal &_.forward_& file, and is tested for validity under
2788 that interpretation. See sections &<<SECTitenonfilred>>& to
2789 &<<SECTspecitredli>>& for a description of the possible contents of non-filter
2790 redirection lists.
2792 The result of an Exim command that uses &%-bf%&, provided no errors are
2793 detected, is a list of the actions that Exim would try to take if presented
2794 with the message for real. More details of filter testing are given in the
2795 separate document entitled &'Exim's interfaces to mail filtering'&.
2797 When testing a filter file,
2798 .cindex "&""From""& line"
2799 .cindex "envelope sender"
2800 .oindex "&%-f%&" "for filter testing"
2801 the envelope sender can be set by the &%-f%& option,
2802 or by a &"From&~"& line at the start of the test message. Various parameters
2803 that would normally be taken from the envelope recipient address of the message
2804 can be set by means of additional command line options (see the next four
2805 options).
2807 .vitem &%-bfd%&&~<&'domain'&>
2808 .oindex "&%-bfd%&"
2809 .vindex "&$qualify_domain$&"
2810 This sets the domain of the recipient address when a filter file is being
2811 tested by means of the &%-bf%& option. The default is the value of
2812 &$qualify_domain$&.
2814 .vitem &%-bfl%&&~<&'local&~part'&>
2815 .oindex "&%-bfl%&"
2816 This sets the local part of the recipient address when a filter file is being
2817 tested by means of the &%-bf%& option. The default is the username of the
2818 process that calls Exim. A local part should be specified with any prefix or
2819 suffix stripped, because that is how it appears to the filter when a message is
2820 actually being delivered.
2822 .vitem &%-bfp%&&~<&'prefix'&>
2823 .oindex "&%-bfp%&"
2824 This sets the prefix of the local part of the recipient address when a filter
2825 file is being tested by means of the &%-bf%& option. The default is an empty
2826 prefix.
2828 .vitem &%-bfs%&&~<&'suffix'&>
2829 .oindex "&%-bfs%&"
2830 This sets the suffix of the local part of the recipient address when a filter
2831 file is being tested by means of the &%-bf%& option. The default is an empty
2832 suffix.
2834 .vitem &%-bh%&&~<&'IP&~address'&>
2835 .oindex "&%-bh%&"
2836 .cindex "testing" "incoming SMTP"
2837 .cindex "SMTP" "testing incoming"
2838 .cindex "testing" "relay control"
2839 .cindex "relaying" "testing configuration"
2840 .cindex "policy control" "testing"
2841 .cindex "debugging" "&%-bh%& option"
2842 This option runs a fake SMTP session as if from the given IP address, using the
2843 standard input and output. The IP address may include a port number at the end,
2844 after a full stop. For example:
2845 .code
2846 exim -bh
2847 exim -bh fe80::a00:20ff:fe86:a061.5678
2848 .endd
2849 When an IPv6 address is given, it is converted into canonical form. In the case
2850 of the second example above, the value of &$sender_host_address$& after
2851 conversion to the canonical form is
2852 &`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2854 Comments as to what is going on are written to the standard error file. These
2855 include lines beginning with &"LOG"& for anything that would have been logged.
2856 This facility is provided for testing configuration options for incoming
2857 messages, to make sure they implement the required policy. For example, you can
2858 test your relay controls using &%-bh%&.
2860 &*Warning 1*&:
2861 .cindex "RFC 1413"
2862 You can test features of the configuration that rely on ident (RFC 1413)
2863 information by using the &%-oMt%& option. However, Exim cannot actually perform
2864 an ident callout when testing using &%-bh%& because there is no incoming SMTP
2865 connection.
2867 &*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2868 are also skipped when testing using &%-bh%&. If you want these callouts to
2869 occur, use &%-bhc%& instead.
2871 Messages supplied during the testing session are discarded, and nothing is
2872 written to any of the real log files. There may be pauses when DNS (and other)
2873 lookups are taking place, and of course these may time out. The &%-oMi%& option
2874 can be used to specify a specific IP interface and port if this is important,
2875 and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2876 session were authenticated.
2878 The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
2879 output just states whether a given recipient address from a given host is
2880 acceptable or not. See section &<<SECTcheckaccess>>&.
2882 Features such as authentication and encryption, where the client input is not
2883 plain text, cannot easily be tested with &%-bh%&. Instead, you should use a
2884 specialized SMTP test program such as
2885 &url(,swaks).
2887 .vitem &%-bhc%&&~<&'IP&~address'&>
2888 .oindex "&%-bhc%&"
2889 This option operates in the same way as &%-bh%&, except that address
2890 verification callouts are performed if required. This includes consulting and
2891 updating the callout cache database.
2893 .vitem &%-bi%&
2894 .oindex "&%-bi%&"
2895 .cindex "alias file" "building"
2896 .cindex "building alias file"
2897 .cindex "Sendmail compatibility" "&%-bi%& option"
2898 Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
2899 Exim does not have the concept of a single alias file, and so it cannot mimic
2900 this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
2901 tend to appear in various scripts such as NIS make files, so the option must be
2902 recognized.
2904 If &%-bi%& is encountered, the command specified by the &%bi_command%&
2905 configuration option is run, under the uid and gid of the caller of Exim. If
2906 the &%-oA%& option is used, its value is passed to the command as an argument.
2907 The command set by &%bi_command%& may not contain arguments. The command can
2908 use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2909 if this is required. If the &%bi_command%& option is not set, calling Exim with
2910 &%-bi%& is a no-op.
2912 .vitem &%-bm%&
2913 .oindex "&%-bm%&"
2914 .cindex "local message reception"
2915 This option runs an Exim receiving process that accepts an incoming,
2916 locally-generated message on the current input. The recipients are given as the
2917 command arguments (except when &%-t%& is also present &-- see below). Each
2918 argument can be a comma-separated list of RFC 2822 addresses. This is the
2919 default option for selecting the overall action of an Exim call; it is assumed
2920 if no other conflicting option is present.
2922 If any addresses in the message are unqualified (have no domain), they are
2923 qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
2924 options, as appropriate. The &%-bnq%& option (see below) provides a way of
2925 suppressing this for special cases.
2927 Policy checks on the contents of local messages can be enforced by means of
2928 the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
2930 .cindex "return code" "for &%-bm%&"
2931 The return code is zero if the message is successfully accepted. Otherwise, the
2932 action is controlled by the &%-oe%&&'x'& option setting &-- see below.
2934 The format
2935 .cindex "message" "format"
2936 .cindex "format" "message"
2937 .cindex "&""From""& line"
2938 .cindex "UUCP" "&""From""& line"
2939 .cindex "Sendmail compatibility" "&""From""& line"
2940 of the message must be as defined in RFC 2822, except that, for
2941 compatibility with Sendmail and Smail, a line in one of the forms
2942 .code
2943 From sender Fri Jan 5 12:55 GMT 1997
2944 From sender Fri, 5 Jan 97 12:55:01
2945 .endd
2946 (with the weekday optional, and possibly with additional text after the date)
2947 is permitted to appear at the start of the message. There appears to be no
2948 authoritative specification of the format of this line. Exim recognizes it by
2949 matching against the regular expression defined by the &%uucp_from_pattern%&
2950 option, which can be changed if necessary.
2952 .oindex "&%-f%&" "overriding &""From""& line"
2953 The specified sender is treated as if it were given as the argument to the
2954 &%-f%& option, but if a &%-f%& option is also present, its argument is used in
2955 preference to the address taken from the message. The caller of Exim must be a
2956 trusted user for the sender of a message to be set in this way.
2958 .vitem &%-bnq%&
2959 .oindex "&%-bnq%&"
2960 .cindex "address qualification, suppressing"
2961 By default, Exim automatically qualifies unqualified addresses (those
2962 without domains) that appear in messages that are submitted locally (that
2963 is, not over TCP/IP). This qualification applies both to addresses in
2964 envelopes, and addresses in header lines. Sender addresses are qualified using
2965 &%qualify_domain%&, and recipient addresses using &%qualify_recipient%& (which
2966 defaults to the value of &%qualify_domain%&).
2968 Sometimes, qualification is not wanted. For example, if &%-bS%& (batch SMTP) is
2969 being used to re-submit messages that originally came from remote hosts after
2970 content scanning, you probably do not want to qualify unqualified addresses in
2971 header lines. (Such lines will be present only if you have not enabled a header
2972 syntax check in the appropriate ACL.)
2974 The &%-bnq%& option suppresses all qualification of unqualified addresses in
2975 messages that originate on the local host. When this is used, unqualified
2976 addresses in the envelope provoke errors (causing message rejection) and
2977 unqualified addresses in header lines are left alone.
2980 .vitem &%-bP%&
2981 .oindex "&%-bP%&"
2982 .cindex "configuration options" "extracting"
2983 .cindex "options" "configuration &-- extracting"
2984 If this option is given with no arguments, it causes the values of all Exim's
2985 main configuration options to be written to the standard output. The values
2986 of one or more specific options can be requested by giving their names as
2987 arguments, for example:
2988 .code
2989 exim -bP qualify_domain hold_domains
2990 .endd
2991 .cindex "hiding configuration option values"
2992 .cindex "configuration options" "hiding value of"
2993 .cindex "options" "hiding value of"
2994 However, any option setting that is preceded by the word &"hide"& in the
2995 configuration file is not shown in full, except to an admin user. For other
2996 users, the output is as in this example:
2997 .code
2998 mysql_servers = <value not displayable>
2999 .endd
3000 If &%configure_file%& is given as an argument, the name of the run time
3001 configuration file is output.
3002 If a list of configuration files was supplied, the value that is output here
3003 is the name of the file that was actually used.
3005 .cindex "daemon" "process id (pid)"
3006 .cindex "pid (process id)" "of daemon"
3007 If &%log_file_path%& or &%pid_file_path%& are given, the names of the
3008 directories where log files and daemon pid files are written are output,
3009 respectively. If these values are unset, log files are written in a
3010 sub-directory of the spool directory called &%log%&, and the pid file is
3011 written directly into the spool directory.
3013 If &%-bP%& is followed by a name preceded by &`+`&, for example,
3014 .code
3015 exim -bP +local_domains
3016 .endd
3017 it searches for a matching named list of any type (domain, host, address, or
3018 local part) and outputs what it finds.
3020 .cindex "options" "router &-- extracting"
3021 .cindex "options" "transport &-- extracting"
3022 .cindex "options" "authenticator &-- extracting"
3023 If one of the words &%router%&, &%transport%&, or &%authenticator%& is given,
3024 followed by the name of an appropriate driver instance, the option settings for
3025 that driver are output. For example:
3026 .code
3027 exim -bP transport local_delivery
3028 .endd
3029 The generic driver options are output first, followed by the driver's private
3030 options. A list of the names of drivers of a particular type can be obtained by
3031 using one of the words &%router_list%&, &%transport_list%&, or
3032 &%authenticator_list%&, and a complete list of all drivers with their option
3033 settings can be obtained by using &%routers%&, &%transports%&, or
3034 &%authenticators%&.
3036 .cindex "options" "macro &-- extracting"
3037 If invoked by an admin user, then &%macro%&, &%macro_list%& and &%macros%&
3038 are available, similarly to the drivers. Because macros are sometimes used
3039 for storing passwords, this option is restricted.
3040 The output format is one item per line.
3042 .vitem &%-bp%&
3043 .oindex "&%-bp%&"
3044 .cindex "queue" "listing messages on"
3045 .cindex "listing" "messages on the queue"
3046 This option requests a listing of the contents of the mail queue on the
3047 standard output. If the &%-bp%& option is followed by a list of message ids,
3048 just those messages are listed. By default, this option can be used only by an
3049 admin user. However, the &%queue_list_requires_admin%& option can be set false
3050 to allow any user to see the queue.
3052 Each message on the queue is displayed as in the following example:
3053 .code
3054 25m 2.9K 0t5C6f-0000c8-00 <alice@wonderland.fict.example>
3055 red.king@looking-glass.fict.example
3056 <other addresses>
3057 .endd
3058 .cindex "message" "size in queue listing"
3059 .cindex "size" "of message"
3060 The first line contains the length of time the message has been on the queue
3061 (in this case 25 minutes), the size of the message (2.9K), the unique local
3062 identifier for the message, and the message sender, as contained in the
3063 envelope. For bounce messages, the sender address is empty, and appears as
3064 &"<>"&. If the message was submitted locally by an untrusted user who overrode
3065 the default sender address, the user's login name is shown in parentheses
3066 before the sender address.
3068 .cindex "frozen messages" "in queue listing"
3069 If the message is frozen (attempts to deliver it are suspended) then the text
3070 &"*** frozen ***"& is displayed at the end of this line.
3072 The recipients of the message (taken from the envelope, not the headers) are
3073 displayed on subsequent lines. Those addresses to which the message has already
3074 been delivered are marked with the letter D. If an original address gets
3075 expanded into several addresses via an alias or forward file, the original is
3076 displayed with a D only when deliveries for all of its child addresses are
3077 complete.
3080 .vitem &%-bpa%&
3081 .oindex "&%-bpa%&"
3082 This option operates like &%-bp%&, but in addition it shows delivered addresses
3083 that were generated from the original top level address(es) in each message by
3084 alias or forwarding operations. These addresses are flagged with &"+D"& instead
3085 of just &"D"&.
3088 .vitem &%-bpc%&
3089 .oindex "&%-bpc%&"
3090 .cindex "queue" "count of messages on"
3091 This option counts the number of messages on the queue, and writes the total
3092 to the standard output. It is restricted to admin users, unless
3093 &%queue_list_requires_admin%& is set false.
3096 .vitem &%-bpr%&
3097 .oindex "&%-bpr%&"
3098 This option operates like &%-bp%&, but the output is not sorted into
3099 chronological order of message arrival. This can speed it up when there are
3100 lots of messages on the queue, and is particularly useful if the output is
3101 going to be post-processed in a way that doesn't need the sorting.
3103 .vitem &%-bpra%&
3104 .oindex "&%-bpra%&"
3105 This option is a combination of &%-bpr%& and &%-bpa%&.
3107 .vitem &%-bpru%&
3108 .oindex "&%-bpru%&"
3109 This option is a combination of &%-bpr%& and &%-bpu%&.
3112 .vitem &%-bpu%&
3113 .oindex "&%-bpu%&"
3114 This option operates like &%-bp%& but shows only undelivered top-level
3115 addresses for each message displayed. Addresses generated by aliasing or
3116 forwarding are not shown, unless the message was deferred after processing by a
3117 router with the &%one_time%& option set.
3120 .vitem &%-brt%&
3121 .oindex "&%-brt%&"
3122 .cindex "testing" "retry configuration"
3123 .cindex "retry" "configuration testing"
3124 This option is for testing retry rules, and it must be followed by up to three
3125 arguments. It causes Exim to look for a retry rule that matches the values
3126 and to write it to the standard output. For example:
3127 .code
3128 exim -brt bach.comp.mus.example
3129 Retry rule: *.comp.mus.example F,2h,15m; F,4d,30m;
3130 .endd
3131 See chapter &<<CHAPretry>>& for a description of Exim's retry rules. The first
3132 argument, which is required, can be a complete address in the form
3133 &'local_part@domain'&, or it can be just a domain name. If the second argument
3134 contains a dot, it is interpreted as an optional second domain name; if no
3135 retry rule is found for the first argument, the second is tried. This ties in
3136 with Exim's behaviour when looking for retry rules for remote hosts &-- if no
3137 rule is found that matches the host, one that matches the mail domain is
3138 sought. Finally, an argument that is the name of a specific delivery error, as
3139 used in setting up retry rules, can be given. For example:
3140 .code
3141 exim -brt haydn.comp.mus.example quota_3d
3142 Retry rule: *@haydn.comp.mus.example quota_3d F,1h,15m
3143 .endd
3145 .vitem &%-brw%&
3146 .oindex "&%-brw%&"
3147 .cindex "testing" "rewriting"
3148 .cindex "rewriting" "testing"
3149 This option is for testing address rewriting rules, and it must be followed by
3150 a single argument, consisting of either a local part without a domain, or a
3151 complete address with a fully qualified domain. Exim outputs how this address
3152 would be rewritten for each possible place it might appear. See chapter
3153 &<<CHAPrewrite>>& for further details.
3155 .vitem &%-bS%&
3156 .oindex "&%-bS%&"
3157 .cindex "SMTP" "batched incoming"
3158 .cindex "batched SMTP input"
3159 This option is used for batched SMTP input, which is an alternative interface
3160 for non-interactive local message submission. A number of messages can be
3161 submitted in a single run. However, despite its name, this is not really SMTP
3162 input. Exim reads each message's envelope from SMTP commands on the standard
3163 input, but generates no responses. If the caller is trusted, or
3164 &%untrusted_set_sender%& is set, the senders in the SMTP MAIL commands are
3165 believed; otherwise the sender is always the caller of Exim.
3167 The message itself is read from the standard input, in SMTP format (leading
3168 dots doubled), terminated by a line containing just a single dot. An error is
3169 provoked if the terminating dot is missing. A further message may then follow.
3171 As for other local message submissions, the contents of incoming batch SMTP
3172 messages can be checked using the non-SMTP ACL (see chapter &<<CHAPACL>>&).
3173 Unqualified addresses are automatically qualified using &%qualify_domain%& and
3174 &%qualify_recipient%&, as appropriate, unless the &%-bnq%& option is used.
3176 Some other SMTP commands are recognized in the input. HELO and EHLO act
3177 as RSET; VRFY, EXPN, ETRN, and HELP act as NOOP;
3178 QUIT quits, ignoring the rest of the standard input.
3180 .cindex "return code" "for &%-bS%&"
3181 If any error is encountered, reports are written to the standard output and
3182 error streams, and Exim gives up immediately. The return code is 0 if no error
3183 was detected; it is 1 if one or more messages were accepted before the error
3184 was detected; otherwise it is 2.
3186 More details of input using batched SMTP are given in section
3187 &<<SECTincomingbatchedSMTP>>&.
3189 .vitem &%-bs%&
3190 .oindex "&%-bs%&"
3191 .cindex "SMTP" "local input"
3192 .cindex "local SMTP input"
3193 This option causes Exim to accept one or more messages by reading SMTP commands
3194 on the standard input, and producing SMTP replies on the standard output. SMTP
3195 policy controls, as defined in ACLs (see chapter &<<CHAPACL>>&) are applied.
3196 Some user agents use this interface as a way of passing locally-generated
3197 messages to the MTA.
3199 In
3200 .cindex "sender" "source of"
3201 this usage, if the caller of Exim is trusted, or &%untrusted_set_sender%& is
3202 set, the senders of messages are taken from the SMTP MAIL commands.
3203 Otherwise the content of these commands is ignored and the sender is set up as
3204 the calling user. Unqualified addresses are automatically qualified using
3205 &%qualify_domain%& and &%qualify_recipient%&, as appropriate, unless the
3206 &%-bnq%& option is used.
3208 .cindex "inetd"
3209 The
3210 &%-bs%& option is also used to run Exim from &'inetd'&, as an alternative to
3211 using a listening daemon. Exim can distinguish the two cases by checking
3212 whether the standard input is a TCP/IP socket. When Exim is called from
3213 &'inetd'&, the source of the mail is assumed to be remote, and the comments
3214 above concerning senders and qualification do not apply. In this situation,
3215 Exim behaves in exactly the same way as it does when receiving a message via
3216 the listening daemon.
3218 .new
3219 .vitem &%-bmalware%&&~<&'filename'&>
3220 .oindex "&%-bmalware%&"
3221 .cindex "testing", "malware"
3222 .cindex "malware scan test"
3223 This debugging option causes Exim to scan the given file,
3224 using the malware scanning framework. The option of &%av_scanner%& influences
3225 this option, so if &%av_scanner%&'s value is dependent upon an expansion then
3226 the expansion should have defaults which apply to this invocation. ACLs are
3227 not invoked, so if &%av_scanner%& references an ACL variable then that variable
3228 will never be populated and &%-bmalware%& will fail.
3230 Exim will have changed working directory before resolving the filename, so
3231 using fully qualified pathnames is advisable. Exim will be running as the Exim
3232 user when it tries to open the file, rather than as the invoking user.
3233 This option requires admin privileges.
3235 The &%-bmalware%& option will not be extended to be more generally useful,
3236 there are better tools for file-scanning. This option exists to help
3237 administrators verify their Exim and AV scanner configuration.
3238 .wen
3240 .vitem &%-bt%&
3241 .oindex "&%-bt%&"
3242 .cindex "testing" "addresses"
3243 .cindex "address" "testing"
3244 This option runs Exim in address testing mode, in which each argument is taken
3245 as a recipient address to be tested for deliverability. The results are
3246 written to the standard output. If a test fails, and the caller is not an admin
3247 user, no details of the failure are output, because these might contain
3248 sensitive information such as usernames and passwords for database lookups.
3250 If no arguments are given, Exim runs in an interactive manner, prompting with a
3251 right angle bracket for addresses to be tested.
3253 Unlike the &%-be%& test option, you cannot arrange for Exim to use the
3254 &[readline()]& function, because it is running as &'root'& and there are
3255 security issues.
3257 Each address is handled as if it were the recipient address of a message
3258 (compare the &%-bv%& option). It is passed to the routers and the result is
3259 written to the standard output. However, any router that has
3260 &%no_address_test%& set is bypassed. This can make &%-bt%& easier to use for
3261 genuine routing tests if your first router passes everything to a scanner
3262 program.
3264 .cindex "return code" "for &%-bt%&"
3265 The return code is 2 if any address failed outright; it is 1 if no address
3266 failed outright but at least one could not be resolved for some reason. Return
3267 code 0 is given only when all addresses succeed.
3269 .cindex "duplicate addresses"
3270 &*Note*&: When actually delivering a message, Exim removes duplicate recipient
3271 addresses after routing is complete, so that only one delivery takes place.
3272 This does not happen when testing with &%-bt%&; the full results of routing are
3273 always shown.
3275 &*Warning*&: &%-bt%& can only do relatively simple testing. If any of the
3276 routers in the configuration makes any tests on the sender address of a
3277 message,
3278 .oindex "&%-f%&" "for address testing"
3279 you can use the &%-f%& option to set an appropriate sender when running
3280 &%-bt%& tests. Without it, the sender is assumed to be the calling user at the
3281 default qualifying domain. However, if you have set up (for example) routers
3282 whose behaviour depends on the contents of an incoming message, you cannot test
3283 those conditions using &%-bt%&. The &%-N%& option provides a possible way of
3284 doing such tests.
3286 .new
3287 .vitem &%-bV%&
3288 .oindex "&%-bV%&"
3289 .cindex "version number of Exim"
3290 This option causes Exim to write the current version number, compilation
3291 number, and compilation date of the &'exim'& binary to the standard output.
3292 It also lists the DBM library that is being used, the optional modules (such as
3293 specific lookup types), the drivers that are included in the binary, and the
3294 name of the run time configuration file that is in use.
3295 .wen
3296 As part of its operation, &%-bV%& causes Exim to read and syntax check its
3297 configuration file. However, this is a static check only. It cannot check
3298 values that are to be expanded. For example, although a misspelt ACL verb is
3299 detected, an error in the verb's arguments is not. You cannot rely on &%-bV%&
3300 alone to discover (for example) all the typos in the configuration; some
3301 realistic testing is needed. The &%-bh%& and &%-N%& options provide more
3302 dynamic testing facilities.
3304 .vitem &%-bv%&
3305 .oindex "&%-bv%&"
3306 .cindex "verifying address" "using &%-bv%&"
3307 .cindex "address" "verification"
3308 This option runs Exim in address verification mode, in which each argument is
3309 taken as a recipient address to be verified by the routers. (This does
3310 not involve any verification callouts). During normal operation, verification
3311 happens mostly as a consequence processing a &%verify%& condition in an ACL
3312 (see chapter &<<CHAPACL>>&). If you want to test an entire ACL, possibly
3313 including callouts, see the &%-bh%& and &%-bhc%& options.
3315 If verification fails, and the caller is not an admin user, no details of the
3316 failure are output, because these might contain sensitive information such as
3317 usernames and passwords for database lookups.
3319 If no arguments are given, Exim runs in an interactive manner, prompting with a
3320 right angle bracket for addresses to be verified.
3322 Unlike the &%-be%& test option, you cannot arrange for Exim to use the
3323 &[readline()]& function, because it is running as &'exim'& and there are
3324 security issues.
3326 Verification differs from address testing (the &%-bt%& option) in that routers
3327 that have &%no_verify%& set are skipped, and if the address is accepted by a
3328 router that has &%fail_verify%& set, verification fails. The address is
3329 verified as a recipient if &%-bv%& is used; to test verification for a sender
3330 address, &%-bvs%& should be used.
3332 If the &%-v%& option is not set, the output consists of a single line for each
3333 address, stating whether it was verified or not, and giving a reason in the
3334 latter case. Without &%-v%&, generating more than one address by redirection
3335 causes verification to end successfully, without considering the generated
3336 addresses. However, if just one address is generated, processing continues,
3337 and the generated address must verify successfully for the overall verification
3338 to succeed.
3340 When &%-v%& is set, more details are given of how the address has been handled,
3341 and in the case of address redirection, all the generated addresses are also
3342 considered. Verification may succeed for some and fail for others.
3344 The
3345 .cindex "return code" "for &%-bv%&"
3346 return code is 2 if any address failed outright; it is 1 if no address
3347 failed outright but at least one could not be resolved for some reason. Return
3348 code 0 is given only when all addresses succeed.
3350 If any of the routers in the configuration makes any tests on the sender
3351 address of a message, you should use the &%-f%& option to set an appropriate
3352 sender when running &%-bv%& tests. Without it, the sender is assumed to be the
3353 calling user at the default qualifying domain.
3355 .vitem &%-bvs%&
3356 .oindex "&%-bvs%&"
3357 This option acts like &%-bv%&, but verifies the address as a sender rather
3358 than a recipient address. This affects any rewriting and qualification that
3359 might happen.
3361 .vitem &%-C%&&~<&'filelist'&>
3362 .oindex "&%-C%&"
3363 .cindex "configuration file" "alternate"
3364 .cindex "CONFIGURE_FILE"
3365 .cindex "alternate configuration file"
3366 This option causes Exim to find the run time configuration file from the given
3367 list instead of from the list specified by the CONFIGURE_FILE
3368 compile-time setting. Usually, the list will consist of just a single file
3369 name, but it can be a colon-separated list of names. In this case, the first
3370 file that exists is used. Failure to open an existing file stops Exim from
3371 proceeding any further along the list, and an error is generated.
3373 .new
3374 When this option is used by a caller other than root, and the list is different
3375 from the compiled-in list, Exim gives up its root privilege immediately, and
3376 runs with the real and effective uid and gid set to those of the caller.
3377 However, if a TRUSTED_CONFIG_LIST file is defined in &_Local/Makefile_&, that
3378 file contains a list of full pathnames, one per line, for configuration files
3379 which are trusted. Root privilege is retained for any configuration file so
3380 listed, as long as the caller is the Exim user (or the user specified in the
3381 CONFIGURE_OWNER option, if any), and as long as the configuration file is
3382 not writeable by inappropriate users or groups.
3384 Leaving TRUSTED_CONFIG_LIST unset precludes the possibility of testing a
3385 configuration using &%-C%& right through message reception and delivery,
3386 even if the caller is root. The reception works, but by that time, Exim is
3387 running as the Exim user, so when it re-executes to regain privilege for the
3388 delivery, the use of &%-C%& causes privilege to be lost. However, root can
3389 test reception and delivery using two separate commands (one to put a message
3390 on the queue, using &%-odq%&, and another to do the delivery, using &%-M%&).
3391 .wen
3392 If ALT_CONFIG_PREFIX is defined &_in Local/Makefile_&, it specifies a
3393 prefix string with which any file named in a &%-C%& command line option
3394 must start. In addition, the file name must not contain the sequence &`/../`&.
3395 However, if the value of the &%-C%& option is identical to the value of
3396 CONFIGURE_FILE in &_Local/Makefile_&, Exim ignores &%-C%& and proceeds as
3397 usual. There is no default setting for ALT_CONFIG_PREFIX; when it is
3398 unset, any file name can be used with &%-C%&.
3400 ALT_CONFIG_PREFIX can be used to confine alternative configuration files
3401 to a directory to which only root has access. This prevents someone who has
3402 broken into the Exim account from running a privileged Exim with an arbitrary
3403 configuration file.
3405 The &%-C%& facility is useful for ensuring that configuration files are
3406 syntactically correct, but cannot be used for test deliveries, unless the
3407 caller is privileged, or unless it is an exotic configuration that does not
3408 require privilege. No check is made on the owner or group of the files
3409 specified by this option.
3412 .vitem &%-D%&<&'macro'&>=<&'value'&>
3413 .oindex "&%-D%&"
3414 .cindex "macro" "setting on command line"
3415 This option can be used to override macro definitions in the configuration file
3416 (see section &<<SECTmacrodefs>>&). However, like &%-C%&, if it is used by an
3417 unprivileged caller, it causes Exim to give up its root privilege.
3418 If DISABLE_D_OPTION is defined in &_Local/Makefile_&, the use of &%-D%& is
3419 completely disabled, and its use causes an immediate error exit.
3421 .new
3422 If WHITELIST_D_MACROS is defined in &_Local/Makefile_& then it should be a
3423 colon-separated list of macros which are considered safe and, if &%-D%& only
3424 supplies macros from this list, and the values are acceptable, then Exim will
3425 not give up root privilege if the caller is root, the Exim run-time user, or
3426 the CONFIGURE_OWNER, if set. This is a transition mechanism and is expected
3427 to be removed in the future. Acceptable values for the macros satisfy the
3428 regexp: &`^[A-Za-z0-9_/.-]*$`&
3429 .wen
3430 The entire option (including equals sign if present) must all be within one
3431 command line item. &%-D%& can be used to set the value of a macro to the empty
3432 string, in which case the equals sign is optional. These two commands are
3433 synonymous:
3434 .code
3435 exim -DABC ...
3436 exim -DABC= ...
3437 .endd
3438 To include spaces in a macro definition item, quotes must be used. If you use
3439 quotes, spaces are permitted around the macro name and the equals sign. For
3440 example:
3441 .code
3442 exim '-D ABC = something' ...
3443 .endd
3444 &%-D%& may be repeated up to 10 times on a command line.
3447 .vitem &%-d%&<&'debug&~options'&>
3448 .oindex "&%-d%&"
3449 .cindex "debugging" "list of selectors"
3450 .cindex "debugging" "&%-d%& option"
3451 This option causes debugging information to be written to the standard
3452 error stream. It is restricted to admin users because debugging output may show
3453 database queries that contain password information. Also, the details of users'
3454 filter files should be protected. If a non-admin user uses &%-d%&, Exim
3455 writes an error message to the standard error stream and exits with a non-zero
3456 return code.
3458 When &%-d%& is used, &%-v%& is assumed. If &%-d%& is given on its own, a lot of
3459 standard debugging data is output. This can be reduced, or increased to include
3460 some more rarely needed information, by directly following &%-d%& with a string
3461 made up of names preceded by plus or minus characters. These add or remove sets
3462 of debugging data, respectively. For example, &%-d+filter%& adds filter
3463 debugging, whereas &%-d-all+filter%& selects only filter debugging. Note that
3464 no spaces are allowed in the debug setting. The available debugging categories
3465 are:
3466 .display
3467 &`acl `& ACL interpretation
3468 &`auth `& authenticators
3469 &`deliver `& general delivery logic
3470 &`dns `& DNS lookups (see also resolver)
3471 &`dnsbl `& DNS black list (aka RBL) code
3472 &`exec `& arguments for &[execv()]& calls
3473 &`expand `& detailed debugging for string expansions
3474 &`filter `& filter handling
3475 &`hints_lookup `& hints data lookups
3476 &`host_lookup `& all types of name-to-IP address handling
3477 &`ident `& ident lookup
3478 &`interface `& lists of local interfaces
3479 &`lists `& matching things in lists
3480 &`load `& system load checks
3481 &`local_scan `& can be used by &[local_scan()]& (see chapter &&&
3482 &<<CHAPlocalscan>>&)
3483 &`lookup `& general lookup code and all lookups
3484 &`memory `& memory handling
3485 &`pid `& add pid to debug output lines
3486 &`process_info `& setting info for the process log
3487 &`queue_run `& queue runs
3488 &`receive `& general message reception logic
3489 &`resolver `& turn on the DNS resolver's debugging output
3490 &`retry `& retry handling
3491 &`rewrite `& address rewriting
3492 &`route `& address routing
3493 &`timestamp `& add timestamp to debug output lines
3494 &`tls `& TLS logic
3495 &`transport `& transports
3496 &`uid `& changes of uid/gid and looking up uid/gid
3497 &`verify `& address verification logic
3498 &`all `& almost all of the above (see below), and also &%-v%&
3499 .endd
3500 The &`all`& option excludes &`memory`& when used as &`+all`&, but includes it
3501 for &`-all`&. The reason for this is that &`+all`& is something that people
3502 tend to use when generating debug output for Exim maintainers. If &`+memory`&
3503 is included, an awful lot of output that is very rarely of interest is
3504 generated, so it now has to be explicitly requested. However, &`-all`& does
3505 turn everything off.
3507 .cindex "resolver, debugging output"
3508 .cindex "DNS resolver, debugging output"
3509 The &`resolver`& option produces output only if the DNS resolver was compiled
3510 with DEBUG enabled. This is not the case in some operating systems. Also,
3511 unfortunately, debugging output from the DNS resolver is written to stdout
3512 rather than stderr.
3514 The default (&%-d%& with no argument) omits &`expand`&, &`filter`&,
3515 &`interface`&, &`load`&, &`memory`&, &`pid`&, &`resolver`&, and &`timestamp`&.
3516 However, the &`pid`& selector is forced when debugging is turned on for a
3517 daemon, which then passes it on to any re-executed Exims. Exim also
3518 automatically adds the pid to debug lines when several remote deliveries are
3519 run in parallel.
3521 The &`timestamp`& selector causes the current time to be inserted at the start
3522 of all debug output lines. This can be useful when trying to track down delays
3523 in processing.
3525 If the &%debug_print%& option is set in any driver, it produces output whenever
3526 any debugging is selected, or if &%-v%& is used.
3528 .vitem &%-dd%&<&'debug&~options'&>
3529 .oindex "&%-dd%&"
3530 This option behaves exactly like &%-d%& except when used on a command that
3531 starts a daemon process. In that case, debugging is turned off for the
3532 subprocesses that the daemon creates. Thus, it is useful for monitoring the
3533 behaviour of the daemon without creating as much output as full debugging does.
3535 .vitem &%-dropcr%&
3536 .oindex "&%-dropcr%&"
3537 This is an obsolete option that is now a no-op. It used to affect the way Exim
3538 handled CR and LF characters in incoming messages. What happens now is
3539 described in section &<<SECTlineendings>>&.
3541 .vitem &%-E%&
3542 .oindex "&%-E%&"
3543 .cindex "bounce message" "generating"
3544 This option specifies that an incoming message is a locally-generated delivery
3545 failure report. It is used internally by Exim when handling delivery failures
3546 and is not intended for external use. Its only effect is to stop Exim
3547 generating certain messages to the postmaster, as otherwise message cascades
3548 could occur in some situations. As part of the same option, a message id may
3549 follow the characters &%-E%&. If it does, the log entry for the receipt of the
3550 new message contains the id, following &"R="&, as a cross-reference.
3552 .vitem &%-e%&&'x'&
3553 .oindex "&%-e%&&'x'&"
3554 There are a number of Sendmail options starting with &%-oe%& which seem to be
3555 called by various programs without the leading &%o%& in the option. For
3556 example, the &%vacation%& program uses &%-eq%&. Exim treats all options of the
3557 form &%-e%&&'x'& as synonymous with the corresponding &%-oe%&&'x'& options.
3559 .vitem &%-F%&&~<&'string'&>
3560 .oindex "&%-F%&"
3561 .cindex "sender" "name"
3562 .cindex "name" "of sender"
3563 This option sets the sender's full name for use when a locally-generated
3564 message is being accepted. In the absence of this option, the user's &'gecos'&
3565 entry from the password data is used. As users are generally permitted to alter
3566 their &'gecos'& entries, no security considerations are involved. White space
3567 between &%-F%& and the <&'string'&> is optional.
3569 .vitem &%-f%&&~<&'address'&>
3570 .oindex "&%-f%&"
3571 .cindex "sender" "address"
3572 .cindex "address" "sender"
3573 .cindex "trusted users"
3574 .cindex "envelope sender"
3575 .cindex "user" "trusted"
3576 This option sets the address of the envelope sender of a locally-generated
3577 message (also known as the return path). The option can normally be used only
3578 by a trusted user, but &%untrusted_set_sender%& can be set to allow untrusted
3579 users to use it.
3581 Processes running as root or the Exim user are always trusted. Other
3582 trusted users are defined by the &%trusted_users%& or &%trusted_groups%&
3583 options. In the absence of &%-f%&, or if the caller is not trusted, the sender
3584 of a local message is set to the caller's login name at the default qualify
3585 domain.
3587 There is one exception to the restriction on the use of &%-f%&: an empty sender
3588 can be specified by any user, trusted or not, to create a message that can
3589 never provoke a bounce. An empty sender can be specified either as an empty
3590 string, or as a pair of angle brackets with nothing between them, as in these
3591 examples of shell commands:
3592 .code
3593 exim -f '<>' user@domain
3594 exim -f "" user@domain
3595 .endd
3596 In addition, the use of &%-f%& is not restricted when testing a filter file
3597 with &%-bf%& or when testing or verifying addresses using the &%-bt%& or
3598 &%-bv%& options.
3600 Allowing untrusted users to change the sender address does not of itself make
3601 it possible to send anonymous mail. Exim still checks that the &'From:'& header
3602 refers to the local user, and if it does not, it adds a &'Sender:'& header,
3603 though this can be overridden by setting &%no_local_from_check%&.
3605 White
3606 .cindex "&""From""& line"
3607 space between &%-f%& and the <&'address'&> is optional (that is, they can be
3608 given as two arguments or one combined argument). The sender of a
3609 locally-generated message can also be set (when permitted) by an initial
3610 &"From&~"& line in the message &-- see the description of &%-bm%& above &-- but
3611 if &%-f%& is also present, it overrides &"From&~"&.
3613 .vitem &%-G%&
3614 .oindex "&%-G%&"
3615 .cindex "Sendmail compatibility" "&%-G%& option ignored"
3616 This is a Sendmail option which is ignored by Exim.
3618 .vitem &%-h%&&~<&'number'&>
3619 .oindex "&%-h%&"
3620 .cindex "Sendmail compatibility" "&%-h%& option ignored"
3621 This option is accepted for compatibility with Sendmail, but has no effect. (In
3622 Sendmail it overrides the &"hop count"& obtained by counting &'Received:'&
3623 headers.)
3625 .vitem &%-i%&
3626 .oindex "&%-i%&"
3627 .cindex "Solaris" "&'mail'& command"
3628 .cindex "dot" "in incoming non-SMTP message"
3629 This option, which has the same effect as &%-oi%&, specifies that a dot on a
3630 line by itself should not terminate an incoming, non-SMTP message. I can find
3631 no documentation for this option in Solaris 2.4 Sendmail, but the &'mailx'&
3632 command in Solaris 2.4 uses it. See also &%-ti%&.
3634 .vitem &%-M%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3635 .oindex "&%-M%&"
3636 .cindex "forcing delivery"
3637 .cindex "delivery" "forcing attempt"
3638 .cindex "frozen messages" "forcing delivery"
3639 This option requests Exim to run a delivery attempt on each message in turn. If
3640 any of the messages are frozen, they are automatically thawed before the
3641 delivery attempt. The settings of &%queue_domains%&, &%queue_smtp_domains%&,
3642 and &%hold_domains%& are ignored.
3644 Retry
3645 .cindex "hints database" "overriding retry hints"
3646 hints for any of the addresses are overridden &-- Exim tries to deliver even if
3647 the normal retry time has not yet been reached. This option requires the caller
3648 to be an admin user. However, there is an option called &%prod_requires_admin%&
3649 which can be set false to relax this restriction (and also the same requirement
3650 for the &%-q%&, &%-R%&, and &%-S%& options).
3652 The deliveries happen synchronously, that is, the original Exim process does
3653 not terminate until all the delivery attempts have finished. No output is
3654 produced unless there is a serious error. If you want to see what is happening,
3655 use the &%-v%& option as well, or inspect Exim's main log.
3657 .vitem &%-Mar%&&~<&'message&~id'&>&~<&'address'&>&~<&'address'&>&~...
3658 .oindex "&%-Mar%&"
3659 .cindex "message" "adding recipients"
3660 .cindex "recipient" "adding"
3661 This option requests Exim to add the addresses to the list of recipients of the
3662 message (&"ar"& for &"add recipients"&). The first argument must be a message
3663 id, and the remaining ones must be email addresses. However, if the message is
3664 active (in the middle of a delivery attempt), it is not altered. This option
3665 can be used only by an admin user.
3667 .vitem "&%-MC%&&~<&'transport'&>&~<&'hostname'&>&~<&'sequence&~number'&>&&&
3668 &~<&'message&~id'&>"
3669 .oindex "&%-MC%&"
3670 .cindex "SMTP" "passed connection"
3671 .cindex "SMTP" "multiple deliveries"
3672 .cindex "multiple SMTP deliveries"
3673 This option is not intended for use by external callers. It is used internally
3674 by Exim to invoke another instance of itself to deliver a waiting message using
3675 an existing SMTP connection, which is passed as the standard input. Details are
3676 given in chapter &<<CHAPSMTP>>&. This must be the final option, and the caller
3677 must be root or the Exim user in order to use it.
3679 .vitem &%-MCA%&
3680 .oindex "&%-MCA%&"
3681 This option is not intended for use by external callers. It is used internally
3682 by Exim in conjunction with the &%-MC%& option. It signifies that the
3683 connection to the remote host has been authenticated.
3685 .vitem &%-MCP%&
3686 .oindex "&%-MCP%&"
3687 This option is not intended for use by external callers. It is used internally
3688 by Exim in conjunction with the &%-MC%& option. It signifies that the server to
3689 which Exim is connected supports pipelining.
3691 .vitem &%-MCQ%&&~<&'process&~id'&>&~<&'pipe&~fd'&>
3692 .oindex "&%-MCQ%&"
3693 This option is not intended for use by external callers. It is used internally
3694 by Exim in conjunction with the &%-MC%& option when the original delivery was
3695 started by a queue runner. It passes on the process id of the queue runner,
3696 together with the file descriptor number of an open pipe. Closure of the pipe
3697 signals the final completion of the sequence of processes that are passing
3698 messages through the same SMTP connection.
3700 .vitem &%-MCS%&
3701 .oindex "&%-MCS%&"
3702 This option is not intended for use by external callers. It is used internally
3703 by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
3704 SMTP SIZE option should be used on messages delivered down the existing
3705 connection.
3707 .vitem &%-MCT%&
3708 .oindex "&%-MCT%&"
3709 This option is not intended for use by external callers. It is used internally
3710 by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
3711 host to which Exim is connected supports TLS encryption.
3713 .vitem &%-Mc%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3714 .oindex "&%-Mc%&"
3715 .cindex "hints database" "not overridden by &%-Mc%&"
3716 .cindex "delivery" "manually started &-- not forced"
3717 This option requests Exim to run a delivery attempt on each message in turn,
3718 but unlike the &%-M%& option, it does check for retry hints, and respects any
3719 that are found. This option is not very useful to external callers. It is
3720 provided mainly for internal use by Exim when it needs to re-invoke itself in
3721 order to regain root privilege for a delivery (see chapter &<<CHAPsecurity>>&).
3722 However, &%-Mc%& can be useful when testing, in order to run a delivery that
3723 respects retry times and other options such as &%hold_domains%& that are
3724 overridden when &%-M%& is used. Such a delivery does not count as a queue run.
3725 If you want to run a specific delivery as if in a queue run, you should use
3726 &%-q%& with a message id argument. A distinction between queue run deliveries
3727 and other deliveries is made in one or two places.
3729 .vitem &%-Mes%&&~<&'message&~id'&>&~<&'address'&>
3730 .oindex "&%-Mes%&"
3731 .cindex "message" "changing sender"
3732 .cindex "sender" "changing"
3733 This option requests Exim to change the sender address in the message to the
3734 given address, which must be a fully qualified address or &"<>"& (&"es"& for
3735 &"edit sender"&). There must be exactly two arguments. The first argument must
3736 be a message id, and the second one an email address. However, if the message
3737 is active (in the middle of a delivery attempt), its status is not altered.
3738 This option can be used only by an admin user.
3740 .vitem &%-Mf%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3741 .oindex "&%-Mf%&"
3742 .cindex "freezing messages"
3743 .cindex "message" "manually freezing"
3744 This option requests Exim to mark each listed message as &"frozen"&. This
3745 prevents any delivery attempts taking place until the message is &"thawed"&,
3746 either manually or as a result of the &%auto_thaw%& configuration option.
3747 However, if any of the messages are active (in the middle of a delivery
3748 attempt), their status is not altered. This option can be used only by an admin
3749 user.
3751 .vitem &%-Mg%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3752 .oindex "&%-Mg%&"
3753 .cindex "giving up on messages"
3754 .cindex "message" "abandoning delivery attempts"
3755 .cindex "delivery" "abandoning further attempts"
3756 This option requests Exim to give up trying to deliver the listed messages,
3757 including any that are frozen. However, if any of the messages are active,
3758 their status is not altered. For non-bounce messages, a delivery error message
3759 is sent to the sender, containing the text &"cancelled by administrator"&.
3760 Bounce messages are just discarded. This option can be used only by an admin
3761 user.
3763 .vitem &%-Mmad%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3764 .oindex "&%-Mmad%&"
3765 .cindex "delivery" "cancelling all"
3766 This option requests Exim to mark all the recipient addresses in the messages
3767 as already delivered (&"mad"& for &"mark all delivered"&). However, if any
3768 message is active (in the middle of a delivery attempt), its status is not
3769 altered. This option can be used only by an admin user.
3771 .vitem &%-Mmd%&&~<&'message&~id'&>&~<&'address'&>&~<&'address'&>&~...
3772 .oindex "&%-Mmd%&"
3773 .cindex "delivery" "cancelling by address"
3774 .cindex "recipient" "removing"
3775 .cindex "removing recipients"
3776 This option requests Exim to mark the given addresses as already delivered
3777 (&"md"& for &"mark delivered"&). The first argument must be a message id, and
3778 the remaining ones must be email addresses. These are matched to recipient
3779 addresses in the message in a case-sensitive manner. If the message is active
3780 (in the middle of a delivery attempt), its status is not altered. This option
3781 can be used only by an admin user.
3783 .vitem &%-Mrm%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3784 .oindex "&%-Mrm%&"
3785 .cindex "removing messages"
3786 .cindex "abandoning mail"
3787 .cindex "message" "manually discarding"
3788 This option requests Exim to remove the given messages from the queue. No
3789 bounce messages are sent; each message is simply forgotten. However, if any of
3790 the messages are active, their status is not altered. This option can be used
3791 only by an admin user or by the user who originally caused the message to be
3792 placed on the queue.
3794 .vitem &%-Mset%&&~<&'message&~id'&>
3795 .oindex "&%-Mset%&
3796 .cindex "testing" "string expansion"
3797 .cindex "expansion" "testing"
3798 This option is useful only in conjunction with &%-be%& (that is, when testing
3799 string expansions). Exim loads the given message from its spool before doing
3800 the test expansions, thus setting message-specific variables such as
3801 &$message_size$& and the header variables. The &$recipients$& variable is made
3802 available. This feature is provided to make it easier to test expansions that
3803 make use of these variables. However, this option can be used only by an admin
3804 user. See also &%-bem%&.
3806 .vitem &%-Mt%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
3807 .oindex "&%-Mt%&"
3808 .cindex "thawing messages"
3809 .cindex "unfreezing messages"
3810 .cindex "frozen messages" "thawing"
3811 .cindex "message" "thawing frozen"
3812 This option requests Exim to &"thaw"& any of the listed messages that are
3813 &"frozen"&, so that delivery attempts can resume. However, if any of the
3814 messages are active, their status is not altered. This option can be used only
3815 by an admin user.
3817 .vitem &%-Mvb%&&~<&'message&~id'&>
3818 .oindex "&%-Mvb%&"
3819 .cindex "listing" "message body"
3820 .cindex "message" "listing body of"
3821 This option causes the contents of the message body (-D) spool file to be
3822 written to the standard output. This option can be used only by an admin user.
3824 .new
3825 .vitem &%-Mvc%&&~<&'message&~id'&>
3826 .oindex "&%-Mvc%&"
3827 .cindex "message" "listing in RFC 2822 format"
3828 .cindex "listing" "message in RFC 2822 format"
3829 This option causes a copy of the complete message (header lines plus body) to
3830 be written to the standard output in RFC 2822 format. This option can be used
3831 only by an admin user.
3832 .wen
3833 .vitem &%-Mvh%&&~<&'message&~id'&>
3834 .oindex "&%-Mvh%&"
3835 .cindex "listing" "message headers"
3836 .cindex "header lines" "listing"
3837 .cindex "message" "listing header lines"
3838 This option causes the contents of the message headers (-H) spool file to be
3839 written to the standard output. This option can be used only by an admin user.
3841 .vitem &%-Mvl%&&~<&'message&~id'&>
3842 .oindex "&%-Mvl%&"
3843 .cindex "listing" "message log"
3844 .cindex "message" "listing message log"
3845 This option causes the contents of the message log spool file to be written to
3846 the standard output. This option can be used only by an admin user.
3848 .vitem &%-m%&
3849 .oindex "&%-m%&"
3850 This is apparently a synonym for &%-om%& that is accepted by Sendmail, so Exim
3851 treats it that way too.
3853 .vitem &%-N%&
3854 .oindex "&%-N%&"
3855 .cindex "debugging" "&%-N%& option"
3856 .cindex "debugging" "suppressing delivery"
3857 This is a debugging option that inhibits delivery of a message at the transport
3858 level. It implies &%-v%&. Exim goes through many of the motions of delivery &--
3859 it just doesn't actually transport the message, but instead behaves as if it
3860 had successfully done so. However, it does not make any updates to the retry
3861 database, and the log entries for deliveries are flagged with &"*>"& rather
3862 than &"=>"&.
3864 Because &%-N%& discards any message to which it applies, only root or the Exim
3865 user are allowed to use it with &%-bd%&, &%-q%&, &%-R%& or &%-M%&. In other
3866 words, an ordinary user can use it only when supplying an incoming message to
3867 which it will apply. Although transportation never fails when &%-N%& is set, an
3868 address may be deferred because of a configuration problem on a transport, or a
3869 routing problem. Once &%-N%& has been used for a delivery attempt, it sticks to
3870 the message, and applies to any subsequent delivery attempts that may happen
3871 for that message.
3873 .vitem &%-n%&
3874 .oindex "&%-n%&"
3875 .cindex "Sendmail compatibility" "&%-n%& option ignored"
3876 This option is interpreted by Sendmail to mean &"no aliasing"&. It is ignored
3877 by Exim.
3879 .vitem &%-O%&&~<&'data'&>
3880 .oindex "&%-O%&"
3881 This option is interpreted by Sendmail to mean &`set option`&. It is ignored by
3882 Exim.
3884 .vitem &%-oA%&&~<&'file&~name'&>
3885 .oindex "&%-oA%&"
3886 .cindex "Sendmail compatibility" "&%-oA%& option"
3887 This option is used by Sendmail in conjunction with &%-bi%& to specify an
3888 alternative alias file name. Exim handles &%-bi%& differently; see the
3889 description above.
3891 .vitem &%-oB%&&~<&'n'&>
3892 .oindex "&%-oB%&"
3893 .cindex "SMTP" "passed connection"
3894 .cindex "SMTP" "multiple deliveries"
3895 .cindex "multiple SMTP deliveries"
3896 This is a debugging option which limits the maximum number of messages that can
3897 be delivered down one SMTP connection, overriding the value set in any &(smtp)&
3898 transport. If <&'n'&> is omitted, the limit is set to 1.
3900 .vitem &%-odb%&
3901 .oindex "&%-odb%&"
3902 .cindex "background delivery"
3903 .cindex "delivery" "in the background"
3904 This option applies to all modes in which Exim accepts incoming messages,
3905 including the listening daemon. It requests &"background"& delivery of such
3906 messages, which means that the accepting process automatically starts a
3907 delivery process for each message received, but does not wait for the delivery
3908 processes to finish.
3910 When all the messages have been received, the reception process exits,
3911 leaving the delivery processes to finish in their own time. The standard output
3912 and error streams are closed at the start of each delivery process.
3913 This is the default action if none of the &%-od%& options are present.
3915 If one of the queueing options in the configuration file
3916 (&%queue_only%& or &%queue_only_file%&, for example) is in effect, &%-odb%&
3917 overrides it if &%queue_only_override%& is set true, which is the default
3918 setting. If &%queue_only_override%& is set false, &%-odb%& has no effect.
3920 .vitem &%-odf%&
3921 .oindex "&%-odf%&"
3922 .cindex "foreground delivery"
3923 .cindex "delivery" "in the foreground"
3924 This option requests &"foreground"& (synchronous) delivery when Exim has
3925 accepted a locally-generated message. (For the daemon it is exactly the same as
3926 &%-odb%&.) A delivery process is automatically started to deliver the message,
3927 and Exim waits for it to complete before proceeding.
3929 The original Exim reception process does not finish until the delivery
3930 process for the final message has ended. The standard error stream is left open
3931 during deliveries.
3933 However, like &%-odb%&, this option has no effect if &%queue_only_override%& is
3934 false and one of the queueing options in the configuration file is in effect.
3936 If there is a temporary delivery error during foreground delivery, the
3937 message is left on the queue for later delivery, and the original reception
3938 process exits. See chapter &<<CHAPnonqueueing>>& for a way of setting up a
3939 restricted configuration that never queues messages.
3942 .vitem &%-odi%&
3943 .oindex "&%-odi%&"
3944 This option is synonymous with &%-odf%&. It is provided for compatibility with
3945 Sendmail.
3947 .vitem &%-odq%&
3948 .oindex "&%-odq%&"
3949 .cindex "non-immediate delivery"
3950 .cindex "delivery" "suppressing immediate"
3951 .cindex "queueing incoming messages"
3952 This option applies to all modes in which Exim accepts incoming messages,
3953 including the listening daemon. It specifies that the accepting process should
3954 not automatically start a delivery process for each message received. Messages
3955 are placed on the queue, and remain there until a subsequent queue runner
3956 process encounters them. There are several configuration options (such as
3957 &%queue_only%&) that can be used to queue incoming messages under certain
3958 conditions. This option overrides all of them and also &%-odqs%&. It always
3959 forces queueing.
3961 .vitem &%-odqs%&
3962 .oindex "&%-odqs%&"
3963 .cindex "SMTP" "delaying delivery"
3964 This option is a hybrid between &%-odb%&/&%-odi%& and &%-odq%&.
3965 However, like &%-odb%& and &%-odi%&, this option has no effect if
3966 &%queue_only_override%& is false and one of the queueing options in the
3967 configuration file is in effect.
3969 When &%-odqs%& does operate, a delivery process is started for each incoming
3970 message, in the background by default, but in the foreground if &%-odi%& is
3971 also present. The recipient addresses are routed, and local deliveries are done
3972 in the normal way. However, if any SMTP deliveries are required, they are not
3973 done at this time, so the message remains on the queue until a subsequent queue
3974 runner process encounters it. Because routing was done, Exim knows which
3975 messages are waiting for which hosts, and so a number of messages for the same
3976 host can be sent in a single SMTP connection. The &%queue_smtp_domains%&
3977 configuration option has the same effect for specific domains. See also the
3978 &%-qq%& option.
3980 .vitem &%-oee%&
3981 .oindex "&%-oee%&"
3982 .cindex "error" "reporting"
3983 If an error is detected while a non-SMTP message is being received (for
3984 example, a malformed address), the error is reported to the sender in a mail
3985 message.
3987 .cindex "return code" "for &%-oee%&"
3988 Provided
3989 this error message is successfully sent, the Exim receiving process
3990 exits with a return code of zero. If not, the return code is 2 if the problem
3991 is that the original message has no recipients, or 1 any other error. This is
3992 the default &%-oe%&&'x'& option if Exim is called as &'rmail'&.
3994 .vitem &%-oem%&
3995 .oindex "&%-oem%&"
3996 .cindex "error" "reporting"
3997 .cindex "return code" "for &%-oem%&"
3998 This is the same as &%-oee%&, except that Exim always exits with a non-zero
3999 return code, whether or not the error message was successfully sent.