Documentation for multiple TCP clamd servers
[exim.git] / doc / doc-docbook / spec.xfpt
CommitLineData
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1. /////////////////////////////////////////////////////////////////////////////
2. This is the primary source of the Exim Manual. It is an xfpt document that is
3. converted into DocBook XML for subsequent conversion into printing and online
4. formats. The markup used herein is "standard" xfpt markup, with some extras.
5. The markup is summarized in a file called Markup.txt.
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6.
7. WARNING: When you use the .new macro, make sure it appears *before* any
8. adjacent index items; otherwise you get an empty "paragraph" which causes
9. unwanted vertical space.
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10. /////////////////////////////////////////////////////////////////////////////
11
12.include stdflags
13.include stdmacs
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14
15. /////////////////////////////////////////////////////////////////////////////
33393583 16. This outputs the standard DocBook boilerplate.
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17. /////////////////////////////////////////////////////////////////////////////
18
33393583 19.docbook
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20
21. /////////////////////////////////////////////////////////////////////////////
22. These lines are processing instructions for the Simple DocBook Processor that
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23. Philip Hazel has developed as a less cumbersome way of making PostScript and
24. PDFs than using xmlto and fop. They will be ignored by all other XML
25. processors.
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26. /////////////////////////////////////////////////////////////////////////////
27
28.literal xml
29<?sdop
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30 foot_right_recto="&chaptertitle; (&chapternumber;)"
31 foot_right_verso="&chaptertitle; (&chapternumber;)"
3cb1b51e 32 toc_chapter_blanks="yes,yes"
595028e4 33 table_warn_overflow="overprint"
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34?>
35.literal off
9b371988 36
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37. /////////////////////////////////////////////////////////////////////////////
38. This generate the outermost <book> element that wraps then entire document.
39. /////////////////////////////////////////////////////////////////////////////
40
41.book
42
43. /////////////////////////////////////////////////////////////////////////////
2aee48d6 44. These definitions set some parameters and save some typing.
7d837ca7 45. Update the Copyright year (only) when changing content.
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46. /////////////////////////////////////////////////////////////////////////////
47
2341d632 48.set previousversion "4.80"
2aee48d6 49.include ./local_params
f89d2485 50
33393583 51.set ACL "access control lists (ACLs)"
f89d2485 52.set I "&nbsp;&nbsp;&nbsp;&nbsp;"
33393583 53
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54.macro copyyear
552012
56.endmacro
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57
58. /////////////////////////////////////////////////////////////////////////////
59. Additional xfpt markup used by this document, over and above the default
60. provided in the xfpt library.
61. /////////////////////////////////////////////////////////////////////////////
62
63. --- Override the &$ flag to automatically insert a $ with the variable name
64
65.flag &$ $& "<varname>$" "</varname>"
66
67. --- Short flags for daggers in option headings. They will always be inside
68. --- an italic string, but we want the daggers to be roman.
69
70.flag &!! "</emphasis>&dagger;<emphasis>"
71.flag &!? "</emphasis>&Dagger;<emphasis>"
72
73. --- A macro for an Exim option definition heading, generating a one-line
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74. --- table with four columns. For cases when the option name is given with
75. --- a space, so that it can be split, a fifth argument is used for the
76. --- index entry.
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77
78.macro option
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79.arg 5
80.oindex "&%$5%&"
81.endarg
82.arg -5
3cb1b51e 83.oindex "&%$1%&"
0a4e3112 84.endarg
f89d2485 85.itable all 0 0 4 8* left 6* center 6* center 6* right
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86.row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&"
87.endtable
88.endmacro
89
90. --- A macro for the common 2-column tables. The width of the first column
91. --- is suitable for the many tables at the start of the main options chapter;
92. --- the small number of other 2-column tables override it.
93
db9452a9 94.macro table2 196pt 254pt
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95.itable none 0 0 2 $1 left $2 left
96.endmacro
97
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98. --- A macro that generates .row, but puts &I; at the start of the first
99. --- argument, thus indenting it. Assume a minimum of two arguments, and
100. --- allow up to four arguments, which is as many as we'll ever need.
101
102.macro irow
103.arg 4
104.row "&I;$1" "$2" "$3" "$4"
105.endarg
106.arg -4
107.arg 3
108.row "&I;$1" "$2" "$3"
109.endarg
110.arg -3
111.row "&I;$1" "$2"
112.endarg
113.endarg
114.endmacro
115
116. --- Macros for option, variable, and concept index entries. For a "range"
117. --- style of entry, use .scindex for the start and .ecindex for the end. The
118. --- first argument of .scindex and the only argument of .ecindex must be the
119. --- ID that ties them together.
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120
121.macro cindex
122&<indexterm role="concept">&
123&<primary>&$1&</primary>&
124.arg 2
125&<secondary>&$2&</secondary>&
126.endarg
127&</indexterm>&
128.endmacro
129
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130.macro scindex
131&<indexterm role="concept" id="$1" class="startofrange">&
132&<primary>&$2&</primary>&
133.arg 3
134&<secondary>&$3&</secondary>&
135.endarg
136&</indexterm>&
137.endmacro
138
139.macro ecindex
140&<indexterm role="concept" startref="$1" class="endofrange"/>&
141.endmacro
142
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143.macro oindex
144&<indexterm role="option">&
145&<primary>&$1&</primary>&
146.arg 2
147&<secondary>&$2&</secondary>&
148.endarg
149&</indexterm>&
150.endmacro
151
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152.macro vindex
153&<indexterm role="variable">&
154&<primary>&$1&</primary>&
155.arg 2
156&<secondary>&$2&</secondary>&
157.endarg
158&</indexterm>&
159.endmacro
160
9b371988 161.macro index
f89d2485 162.echo "** Don't use .index; use .cindex or .oindex or .vindex"
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163.endmacro
164. ////////////////////////////////////////////////////////////////////////////
165
166
167. ////////////////////////////////////////////////////////////////////////////
168. The <bookinfo> element is removed from the XML before processing for Ascii
169. output formats.
170. ////////////////////////////////////////////////////////////////////////////
171
172.literal xml
173<bookinfo>
174<title>Specification of the Exim Mail Transfer Agent</title>
175<titleabbrev>The Exim MTA</titleabbrev>
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176<date>
177.fulldate
178</date>
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179<author><firstname>Exim</firstname><surname>Maintainers</surname></author>
180<authorinitials>EM</authorinitials>
9b371988 181<revhistory><revision>
99474a17 182.versiondatexml
7b4c60eb 183 <authorinitials>EM</authorinitials>
9b371988 184</revision></revhistory>
2aee48d6 185<copyright><year>
29343b08 186.copyyear
2aee48d6 187 </year><holder>University of Cambridge</holder></copyright>
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188</bookinfo>
189.literal off
190
191
192. /////////////////////////////////////////////////////////////////////////////
193. This chunk of literal XML implements index entries of the form "x, see y" and
194. "x, see also y". However, the DocBook DTD doesn't allow <indexterm> entries
195. at the top level, so we have to put the .chapter directive first.
196. /////////////////////////////////////////////////////////////////////////////
197
f89d2485 198.chapter "Introduction" "CHID1"
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199.literal xml
200
f89d2485 201<indexterm role="variable">
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202 <primary>$1, $2, etc.</primary>
203 <see><emphasis>numerical variables</emphasis></see>
204</indexterm>
205<indexterm role="concept">
206 <primary>address</primary>
207 <secondary>rewriting</secondary>
208 <see><emphasis>rewriting</emphasis></see>
209</indexterm>
210<indexterm role="concept">
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211 <primary>Bounce Address Tag Validation</primary>
212 <see><emphasis>BATV</emphasis></see>
213</indexterm>
214<indexterm role="concept">
215 <primary>Client SMTP Authorization</primary>
216 <see><emphasis>CSA</emphasis></see>
217</indexterm>
218<indexterm role="concept">
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219 <primary>CR character</primary>
220 <see><emphasis>carriage return</emphasis></see>
221</indexterm>
222<indexterm role="concept">
223 <primary>CRL</primary>
224 <see><emphasis>certificate revocation list</emphasis></see>
225</indexterm>
226<indexterm role="concept">
227 <primary>delivery</primary>
228 <secondary>failure report</secondary>
229 <see><emphasis>bounce message</emphasis></see>
230</indexterm>
231<indexterm role="concept">
232 <primary>dialup</primary>
233 <see><emphasis>intermittently connected hosts</emphasis></see>
234</indexterm>
235<indexterm role="concept">
236 <primary>exiscan</primary>
237 <see><emphasis>content scanning</emphasis></see>
238</indexterm>
239<indexterm role="concept">
240 <primary>failover</primary>
241 <see><emphasis>fallback</emphasis></see>
242</indexterm>
243<indexterm role="concept">
244 <primary>fallover</primary>
245 <see><emphasis>fallback</emphasis></see>
246</indexterm>
247<indexterm role="concept">
248 <primary>filter</primary>
249 <secondary>Sieve</secondary>
250 <see><emphasis>Sieve filter</emphasis></see>
251</indexterm>
252<indexterm role="concept">
253 <primary>ident</primary>
254 <see><emphasis>RFC 1413</emphasis></see>
255</indexterm>
256<indexterm role="concept">
257 <primary>LF character</primary>
258 <see><emphasis>linefeed</emphasis></see>
259</indexterm>
260<indexterm role="concept">
261 <primary>maximum</primary>
595028e4 262 <seealso><emphasis>limit</emphasis></seealso>
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263</indexterm>
264<indexterm role="concept">
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265 <primary>monitor</primary>
266 <see><emphasis>Exim monitor</emphasis></see>
267</indexterm>
268<indexterm role="concept">
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269 <primary>no_<emphasis>xxx</emphasis></primary>
270 <see>entry for xxx</see>
271</indexterm>
272<indexterm role="concept">
273 <primary>NUL</primary>
274 <see><emphasis>binary zero</emphasis></see>
275</indexterm>
276<indexterm role="concept">
277 <primary>passwd file</primary>
278 <see><emphasis>/etc/passwd</emphasis></see>
279</indexterm>
280<indexterm role="concept">
281 <primary>process id</primary>
282 <see><emphasis>pid</emphasis></see>
283</indexterm>
284<indexterm role="concept">
285 <primary>RBL</primary>
286 <see><emphasis>DNS list</emphasis></see>
287</indexterm>
288<indexterm role="concept">
289 <primary>redirection</primary>
290 <see><emphasis>address redirection</emphasis></see>
291</indexterm>
292<indexterm role="concept">
293 <primary>return path</primary>
294 <seealso><emphasis>envelope sender</emphasis></seealso>
295</indexterm>
296<indexterm role="concept">
297 <primary>scanning</primary>
298 <see><emphasis>content scanning</emphasis></see>
299</indexterm>
300<indexterm role="concept">
301 <primary>SSL</primary>
302 <see><emphasis>TLS</emphasis></see>
303</indexterm>
304<indexterm role="concept">
305 <primary>string</primary>
306 <secondary>expansion</secondary>
307 <see><emphasis>expansion</emphasis></see>
308</indexterm>
309<indexterm role="concept">
310 <primary>top bit</primary>
311 <see><emphasis>8-bit characters</emphasis></see>
312</indexterm>
313<indexterm role="concept">
314 <primary>variables</primary>
315 <see><emphasis>expansion, variables</emphasis></see>
316</indexterm>
317<indexterm role="concept">
318 <primary>zero, binary</primary>
319 <see><emphasis>binary zero</emphasis></see>
320</indexterm>
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321
322.literal off
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323
324
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325. /////////////////////////////////////////////////////////////////////////////
326. This is the real start of the first chapter. See the comment above as to why
327. we can't have the .chapter line here.
328. chapter "Introduction"
329. /////////////////////////////////////////////////////////////////////////////
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330
331Exim is a mail transfer agent (MTA) for hosts that are running Unix or
332Unix-like operating systems. It was designed on the assumption that it would be
333run on hosts that are permanently connected to the Internet. However, it can be
334used on intermittently connected hosts with suitable configuration adjustments.
335
336Configuration files currently exist for the following operating systems: AIX,
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337BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, Dragonfly, FreeBSD, GNU/Hurd,
338GNU/Linux, HI-OSF (Hitachi), HI-UX, HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD,
339OpenUNIX, QNX, SCO, SCO SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4,
340Tru64-Unix (formerly Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware.
341Some of these operating systems are no longer current and cannot easily be
342tested, so the configuration files may no longer work in practice.
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343
344There are also configuration files for compiling Exim in the Cygwin environment
345that can be installed on systems running Windows. However, this document does
346not contain any information about running Exim in the Cygwin environment.
347
348The terms and conditions for the use and distribution of Exim are contained in
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349the file &_NOTICE_&. Exim is distributed under the terms of the GNU General
350Public Licence, a copy of which may be found in the file &_LICENCE_&.
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351
352The use, supply or promotion of Exim for the purpose of sending bulk,
353unsolicited electronic mail is incompatible with the basic aims of the program,
354which revolve around the free provision of a service that enhances the quality
355of personal communications. The author of Exim regards indiscriminate
356mass-mailing as an antisocial, irresponsible abuse of the Internet.
357
358Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
359experience of running and working on the Smail 3 code, I could never have
360contemplated starting to write a new MTA. Many of the ideas and user interfaces
361were originally taken from Smail 3, though the actual code of Exim is entirely
362new, and has developed far beyond the initial concept.
363
364Many people, both in Cambridge and around the world, have contributed to the
365development and the testing of Exim, and to porting it to various operating
366systems. I am grateful to them all. The distribution now contains a file called
9b371988 367&_ACKNOWLEDGMENTS_&, in which I have started recording the names of
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368contributors.
369
370
f89d2485 371.section "Exim documentation" "SECID1"
800d5176 372. Keep this example change bar when updating the documentation!
b52ed2b3 373
800d5176 374.new
9b371988 375.cindex "documentation"
2aee48d6 376This edition of the Exim specification applies to version &version() of Exim.
9b371988 377Substantive changes from the &previousversion; edition are marked in some
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378renditions of the document; this paragraph is so marked if the rendition is
379capable of showing a change indicator.
800d5176 380.wen
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381
382This document is very much a reference manual; it is not a tutorial. The reader
383is expected to have some familiarity with the SMTP mail transfer protocol and
384with general Unix system administration. Although there are some discussions
385and examples in places, the information is mostly organized in a way that makes
386it easy to look up, rather than in a natural order for sequential reading.
387Furthermore, the manual aims to cover every aspect of Exim in detail, including
388a number of rarely-used, special-purpose features that are unlikely to be of
389very wide interest.
390
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391.cindex "books about Exim"
392An &"easier"& discussion of Exim which provides more in-depth explanatory,
393introductory, and tutorial material can be found in a book entitled &'The Exim
595028e4 394SMTP Mail Server'& (second edition, 2007), published by UIT Cambridge
9b371988 395(&url(http://www.uit.co.uk/exim-book/)).
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396
397This book also contains a chapter that gives a general introduction to SMTP and
398Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
399with the latest release of Exim. (Note that the earlier book about Exim,
400published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
401
9b371988 402.cindex "Debian" "information sources"
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403If you are using a Debian distribution of Exim, you will find information about
404Debian-specific features in the file
f89d2485 405&_/usr/share/doc/exim4-base/README.Debian_&.
9b371988 406The command &(man update-exim.conf)& is another source of Debian-specific
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407information.
408
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409.cindex "&_doc/NewStuff_&"
410.cindex "&_doc/ChangeLog_&"
411.cindex "change log"
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412As the program develops, there may be features in newer versions that have not
413yet made it into this document, which is updated only when the most significant
414digit of the fractional part of the version number changes. Specifications of
415new features that are not yet in this manual are placed in the file
9b371988 416&_doc/NewStuff_& in the Exim distribution.
168e428f 417
9b371988 418Some features may be classified as &"experimental"&. These may change
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419incompatibly while they are developing, or even be withdrawn. For this reason,
420they are not documented in this manual. Information about experimental features
9b371988 421can be found in the file &_doc/experimental.txt_&.
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422
423All changes to the program (whether new features, bug fixes, or other kinds of
9b371988 424change) are noted briefly in the file called &_doc/ChangeLog_&.
168e428f 425
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426.cindex "&_doc/spec.txt_&"
427This specification itself is available as an ASCII file in &_doc/spec.txt_& so
428that it can easily be searched with a text editor. Other files in the &_doc_&
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429directory are:
430
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431.table2 100pt
432.row &_OptionLists.txt_& "list of all options in alphabetical order"
433.row &_dbm.discuss.txt_& "discussion about DBM libraries"
434.row &_exim.8_& "a man page of Exim's command line options"
435.row &_experimental.txt_& "documentation of experimental features"
436.row &_filter.txt_& "specification of the filter language"
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437.row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
438.row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
439.endtable
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440
441The main specification and the specification of the filtering language are also
442available in other formats (HTML, PostScript, PDF, and Texinfo). Section
9b371988 443&<<SECTavail>>& below tells you how to get hold of these.
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444
445
446
f89d2485 447.section "FTP and web sites" "SECID2"
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448.cindex "web site"
449.cindex "FTP site"
068aaea8 450The primary site for Exim source distributions is currently the University of
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451Cambridge's FTP site, whose contents are described in &'Where to find the Exim
452distribution'& below. In addition, there is a web site and an FTP site at
453&%exim.org%&. These are now also hosted at the University of Cambridge. The
454&%exim.org%& site was previously hosted for a number of years by Energis
455Squared, formerly Planet Online Ltd, whose support I gratefully acknowledge.
456
457.cindex "wiki"
458.cindex "FAQ"
168e428f 459As well as Exim distribution tar files, the Exim web site contains a number of
f89d2485 460differently formatted versions of the documentation. A recent addition to the
7d0ab55c 461online information is the Exim wiki (&url(http://wiki.exim.org)),
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462which contains what used to be a separate FAQ, as well as various other
463examples, tips, and know-how that have been contributed by Exim users.
464
465.cindex Bugzilla
7d0ab55c 466An Exim Bugzilla exists at &url(http://bugs.exim.org). You can use
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467this to report bugs, and also to add items to the wish list. Please search
468first to check that you are not duplicating a previous entry.
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469
470
471
f89d2485 472.section "Mailing lists" "SECID3"
9b371988 473.cindex "mailing lists" "for Exim users"
f89d2485 474The following Exim mailing lists exist:
168e428f 475
9b371988 476.table2 140pt
d854d3a9 477.row &'exim-announce@exim.org'& "Moderated, low volume announcements list"
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478.row &'exim-users@exim.org'& "General discussion list"
479.row &'exim-dev@exim.org'& "Discussion of bugs, enhancements, etc."
d854d3a9 480.row &'exim-cvs@exim.org'& "Automated commit messages from the VCS"
9b371988 481.endtable
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482
483You can subscribe to these lists, change your existing subscriptions, and view
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484or search the archives via the mailing lists link on the Exim home page.
485.cindex "Debian" "mailing list for"
4f578862 486If you are using a Debian distribution of Exim, you may wish to subscribe to
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487the Debian-specific mailing list &'pkg-exim4-users@lists.alioth.debian.org'&
488via this web page:
489.display
490&url(http://lists.alioth.debian.org/mailman/listinfo/pkg-exim4-users)
491.endd
492Please ask Debian-specific questions on this list and not on the general Exim
493lists.
9b371988 494
f89d2485 495.section "Exim training" "SECID4"
9b371988 496.cindex "training courses"
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497Training courses in Cambridge (UK) used to be run annually by the author of
498Exim, before he retired. At the time of writing, there are no plans to run
499further Exim courses in Cambridge. However, if that changes, relevant
500information will be posted at &url(http://www-tus.csx.cam.ac.uk/courses/exim/).
168e428f 501
f89d2485 502.section "Bug reports" "SECID5"
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503.cindex "bug reports"
504.cindex "reporting bugs"
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505Reports of obvious bugs can be emailed to &'bugs@exim.org'& or reported
506via the Bugzilla (&url(http://bugs.exim.org)). However, if you are unsure
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507whether some behaviour is a bug or not, the best thing to do is to post a
508message to the &'exim-dev'& mailing list and have it discussed.
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509
510
511
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512.section "Where to find the Exim distribution" "SECTavail"
513.cindex "FTP site"
514.cindex "distribution" "ftp site"
168e428f 515The master ftp site for the Exim distribution is
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516.display
517&*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim*&
518.endd
168e428f 519This is mirrored by
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520.display
521&*ftp://ftp.exim.org/pub/exim*&
522.endd
523The file references that follow are relative to the &_exim_& directories at
524these sites. There are now quite a number of independent mirror sites around
525the world. Those that I know about are listed in the file called &_Mirrors_&.
526
527Within the &_exim_& directory there are subdirectories called &_exim3_& (for
528previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
529distributions), and &_Testing_& for testing versions. In the &_exim4_&
168e428f 530subdirectory, the current release can always be found in files called
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531.display
532&_exim-n.nn.tar.gz_&
533&_exim-n.nn.tar.bz2_&
534.endd
535where &'n.nn'& is the highest such version number in the directory. The two
168e428f 536files contain identical data; the only difference is the type of compression.
9b371988 537The &_.bz2_& file is usually a lot smaller than the &_.gz_& file.
168e428f 538
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539.cindex "distribution" "signing details"
540.cindex "distribution" "public key"
541.cindex "public key for signed distribution"
40167b05
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542.new
543The distributions will be PGP signed by an individual key of the Release
544Coordinator. This key will have a uid containing an email address in the
545&'exim.org'& domain and will have signatures from other people, including
546other Exim maintainers. We expect that the key will be in the "strong set" of
547PGP keys. There should be a trust path to that key from Nigel Metheringham's
548PGP key, a version of which can be found in the release directory in the file
549&_nigel-pubkey.asc_&. All keys used will be available in public keyserver pools,
550such as &'pool.sks-keyservers.net'&.
551
552At time of last update, releases were being made by Phil Pennock and signed with
553key &'0x403043153903637F'&, although that key is expected to be replaced in 2013.
554A trust path from Nigel's key to Phil's can be observed at
555&url(https://www.security.spodhuis.org/exim-trustpath).
556.wen
557
558The signatures for the tar bundles are in:
9b371988 559.display
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560&_exim-n.nn.tar.gz.asc_&
561&_exim-n.nn.tar.bz2.asc_&
9b371988 562.endd
168e428f 563For each released version, the log of changes is made separately available in a
9b371988 564separate file in the directory &_ChangeLogs_& so that it is possible to
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565find out what has changed without having to download the entire distribution.
566
9b371988 567.cindex "documentation" "available formats"
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568The main distribution contains ASCII versions of this specification and other
569documentation; other formats of the documents are available in separate files
9b371988
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570inside the &_exim4_& directory of the FTP site:
571.display
572&_exim-html-n.nn.tar.gz_&
573&_exim-pdf-n.nn.tar.gz_&
574&_exim-postscript-n.nn.tar.gz_&
575&_exim-texinfo-n.nn.tar.gz_&
576.endd
577These tar files contain only the &_doc_& directory, not the complete
578distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
168e428f 579
168e428f 580
f89d2485 581.section "Limitations" "SECID6"
9b371988
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582.ilist
583.cindex "limitations of Exim"
584.cindex "bang paths" "not handled by Exim"
585Exim is designed for use as an Internet MTA, and therefore handles addresses in
586RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
587simple two-component bang paths can be converted by a straightforward rewriting
588configuration. This restriction does not prevent Exim from being interfaced to
589UUCP as a transport mechanism, provided that domain addresses are used.
590.next
591.cindex "domainless addresses"
592.cindex "address" "without domain"
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593Exim insists that every address it handles has a domain attached. For incoming
594local messages, domainless addresses are automatically qualified with a
595configured domain value. Configuration options specify from which remote
596systems unqualified addresses are acceptable. These are then qualified on
597arrival.
9b371988
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598.next
599.cindex "transport" "external"
600.cindex "external transports"
601The only external transport mechanisms that are currently implemented are SMTP
602and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
168e428f 603transport is available, and there are facilities for writing messages to files
9b371988
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604and pipes, optionally in &'batched SMTP'& format; these facilities can be used
605to send messages to other transport mechanisms such as UUCP, provided they can
606handle domain-style addresses. Batched SMTP input is also catered for.
607.next
608Exim is not designed for storing mail for dial-in hosts. When the volumes of
609such mail are large, it is better to get the messages &"delivered"& into files
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610(that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
611other means.
9b371988
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612.next
613Although Exim does have basic facilities for scanning incoming messages, these
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614are not comprehensive enough to do full virus or spam scanning. Such operations
615are best carried out using additional specialized software packages. If you
616compile Exim with the content-scanning extension, straightforward interfaces to
617a number of common scanners are provided.
9b371988 618.endlist
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619
620
f89d2485 621.section "Run time configuration" "SECID7"
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622Exim's run time configuration is held in a single text file that is divided
623into a number of sections. The entries in this file consist of keywords and
624values, in the style of Smail 3 configuration files. A default configuration
625file which is suitable for simple online installations is provided in the
9b371988 626distribution, and is described in chapter &<<CHAPdefconfil>>& below.
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627
628
f89d2485 629.section "Calling interface" "SECID8"
9b371988 630.cindex "Sendmail compatibility" "command line interface"
168e428f 631Like many MTAs, Exim has adopted the Sendmail command line interface so that it
9b371988
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632can be a straight replacement for &_/usr/lib/sendmail_& or
633&_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
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634about Sendmail in order to run Exim. For actions other than sending messages,
635Sendmail-compatible options also exist, but those that produce output (for
9b371988 636example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
168e428f 637format. There are also some additional options that are compatible with Smail
9b371988 6383, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
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639documents all Exim's command line options. This information is automatically
640made into the man page that forms part of the Exim distribution.
641
642Control of messages on the queue can be done via certain privileged command
9b371988
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643line options. There is also an optional monitor program called &'eximon'&,
644which displays current information in an X window, and which contains a menu
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645interface to Exim's command line administration options.
646
647
648
f89d2485 649.section "Terminology" "SECID9"
9b371988
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650.cindex "terminology definitions"
651.cindex "body of message" "definition of"
652The &'body'& of a message is the actual data that the sender wants to transmit.
653It is the last part of a message, and is separated from the &'header'& (see
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654below) by a blank line.
655
9b371988 656.cindex "bounce message" "definition of"
168e428f 657When a message cannot be delivered, it is normally returned to the sender in a
9b371988
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658delivery failure message or a &"non-delivery report"& (NDR). The term
659&'bounce'& is commonly used for this action, and the error reports are often
660called &'bounce messages'&. This is a convenient shorthand for &"delivery
661failure error report"&. Such messages have an empty sender address in the
662message's &'envelope'& (see below) to ensure that they cannot themselves give
663rise to further bounce messages.
664
665The term &'default'& appears frequently in this manual. It is used to qualify a
168e428f
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666value which is used in the absence of any setting in the configuration. It may
667also qualify an action which is taken unless a configuration setting specifies
668otherwise.
669
9b371988 670The term &'defer'& is used when the delivery of a message to a specific
168e428f 671destination cannot immediately take place for some reason (a remote host may be
9b371988 672down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
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673until a later time.
674
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675The word &'domain'& is sometimes used to mean all but the first component of a
676host's name. It is &'not'& used in that sense here, where it normally refers to
677the part of an email address following the @ sign.
168e428f 678
f89d2485 679.cindex "envelope, definition of"
9b371988
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680.cindex "sender" "definition of"
681A message in transit has an associated &'envelope'&, as well as a header and a
168e428f
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682body. The envelope contains a sender address (to which bounce messages should
683be delivered), and any number of recipient addresses. References to the
684sender or the recipients of a message usually mean the addresses in the
685envelope. An MTA uses these addresses for delivery, and for returning bounce
686messages, not the addresses that appear in the header lines.
687
f89d2485 688.cindex "message" "header, definition of"
9b371988
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689.cindex "header section" "definition of"
690The &'header'& of a message is the first part of a message's text, consisting
691of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
692&'Subject:'&, etc. Long header lines can be split over several text lines by
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693indenting the continuations. The header is separated from the body by a blank
694line.
695
9b371988
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696.cindex "local part" "definition of"
697.cindex "domain" "definition of"
698The term &'local part'&, which is taken from RFC 2822, is used to refer to that
168e428f 699part of an email address that precedes the @ sign. The part that follows the
9b371988 700@ sign is called the &'domain'& or &'mail domain'&.
168e428f 701
9b371988 702.cindex "local delivery" "definition of"
f89d2485 703.cindex "remote delivery, definition of"
9b371988 704The terms &'local delivery'& and &'remote delivery'& are used to distinguish
168e428f 705delivery to a file or a pipe on the local host from delivery by SMTP over
068aaea8 706TCP/IP to another host. As far as Exim is concerned, all hosts other than the
9b371988 707host it is running on are &'remote'&.
168e428f 708
9b371988
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709.cindex "return path" "definition of"
710&'Return path'& is another name that is used for the sender address in a
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711message's envelope.
712
9b371988
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713.cindex "queue" "definition of"
714The term &'queue'& is used to refer to the set of messages awaiting delivery,
168e428f
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715because this term is in widespread use in the context of MTAs. However, in
716Exim's case the reality is more like a pool than a queue, because there is
717normally no ordering of waiting messages.
718
9b371988
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719.cindex "queue runner" "definition of"
720The term &'queue runner'& is used to describe a process that scans the queue
168e428f 721and attempts to deliver those messages whose retry times have come. This term
9b371988 722is used by other MTAs, and also relates to the command &%runq%&, but in Exim
168e428f
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723the waiting messages are normally processed in an unpredictable order.
724
9b371988
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725.cindex "spool directory" "definition of"
726The term &'spool directory'& is used for a directory in which Exim keeps the
727messages on its queue &-- that is, those that it is in the process of
168e428f 728delivering. This should not be confused with the directory in which local
9b371988
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729mailboxes are stored, which is called a &"spool directory"& by some people. In
730the Exim documentation, &"spool"& is always used in the first sense.
168e428f
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731
732
733
734
735
736
9b371988
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737. ////////////////////////////////////////////////////////////////////////////
738. ////////////////////////////////////////////////////////////////////////////
168e428f 739
f89d2485 740.chapter "Incorporated code" "CHID2"
9b371988
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741.cindex "incorporated code"
742.cindex "regular expressions" "library"
743.cindex "PCRE"
1899bab2 744.cindex "OpenDMARC"
168e428f
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745A number of pieces of external code are included in the Exim distribution.
746
9b371988 747.ilist
210f147e
NM
748Regular expressions are supported in the main Exim program and in the
749Exim monitor using the freely-distributable PCRE library, copyright
40df1be3
TF
750&copy; University of Cambridge. The source to PCRE is no longer shipped with
751Exim, so you will need to use the version of PCRE shipped with your system,
752or obtain and install the full version of the library from
f89d2485 753&url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
9b371988 754.next
f89d2485 755.cindex "cdb" "acknowledgment"
168e428f
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756Support for the cdb (Constant DataBase) lookup method is provided by code
757contributed by Nigel Metheringham of (at the time he contributed it) Planet
9b371988
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758Online Ltd. The implementation is completely contained within the code of Exim.
759It does not link against an external cdb library. The code contains the
760following statements:
761
762.blockquote
763Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
764
168e428f
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765This program is free software; you can redistribute it and/or modify it under
766the terms of the GNU General Public License as published by the Free Software
767Foundation; either version 2 of the License, or (at your option) any later
768version.
168e428f
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769This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
770the spec and sample code for cdb can be obtained from
f89d2485
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771&url(http://www.pobox.com/~djb/cdb.html). This implementation borrows
772some code from Dan Bernstein's implementation (which has no license
773restrictions applied to it).
9b371988
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774.endblockquote
775.next
776.cindex "SPA authentication"
777.cindex "Samba project"
778.cindex "Microsoft Secure Password Authentication"
779Client support for Microsoft's &'Secure Password Authentication'& is provided
168e428f
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780by code contributed by Marc Prud'hommeaux. Server support was contributed by
781Tom Kistner. This includes code taken from the Samba project, which is released
782under the Gnu GPL.
9b371988
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783.next
784.cindex "Cyrus"
785.cindex "&'pwcheck'& daemon"
786.cindex "&'pwauthd'& daemon"
787Support for calling the Cyrus &'pwcheck'& and &'saslauthd'& daemons is provided
168e428f
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788by code taken from the Cyrus-SASL library and adapted by Alexander S.
789Sabourenkov. The permission notice appears below, in accordance with the
790conditions expressed therein.
9b371988
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791
792.blockquote
793Copyright &copy; 2001 Carnegie Mellon University. All rights reserved.
794
168e428f
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795Redistribution and use in source and binary forms, with or without
796modification, are permitted provided that the following conditions
797are met:
168e428f 798
9b371988
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799.olist
800Redistributions of source code must retain the above copyright
801notice, this list of conditions and the following disclaimer.
802.next
803Redistributions in binary form must reproduce the above copyright
168e428f
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804notice, this list of conditions and the following disclaimer in
805the documentation and/or other materials provided with the
806distribution.
9b371988
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807.next
808The name &"Carnegie Mellon University"& must not be used to
168e428f
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809endorse or promote products derived from this software without
810prior written permission. For permission or any other legal
811details, please contact
9b371988 812.display
068aaea8
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813 Office of Technology Transfer
814 Carnegie Mellon University
815 5000 Forbes Avenue
816 Pittsburgh, PA 15213-3890
817 (412) 268-4387, fax: (412) 268-7395
818 tech-transfer@andrew.cmu.edu
9b371988
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819.endd
820.next
821Redistributions of any form whatsoever must retain the following
168e428f 822acknowledgment:
9b371988
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823
824&"This product includes software developed by Computing Services
825at Carnegie Mellon University (&url(http://www.cmu.edu/computing/)."&
826
168e428f
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827CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
828THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
829AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
830FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
831WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
832AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
833OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
9b371988
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834.endlist
835.endblockquote
168e428f 836
9b371988 837.next
f89d2485 838.cindex "Exim monitor" "acknowledgment"
9b371988
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839.cindex "X-windows"
840.cindex "Athena"
168e428f
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841The Exim Monitor program, which is an X-Window application, includes
842modified versions of the Athena StripChart and TextPop widgets.
843This code is copyright by DEC and MIT, and their permission notice appears
844below, in accordance with the conditions expressed therein.
9b371988
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845
846.blockquote
168e428f
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847Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
848and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
9b371988 849
168e428f 850All Rights Reserved
9b371988 851
168e428f
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852Permission to use, copy, modify, and distribute this software and its
853documentation for any purpose and without fee is hereby granted,
854provided that the above copyright notice appear in all copies and that
855both that copyright notice and this permission notice appear in
856supporting documentation, and that the names of Digital or MIT not be
857used in advertising or publicity pertaining to distribution of the
858software without specific, written prior permission.
9b371988 859
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860DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
861ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
862DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
863ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
864WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
865ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
866SOFTWARE.
9b371988 867.endblockquote
168e428f 868
9b371988 869.next
1899bab2
TL
870.cindex "opendmarc" "acknowledgment"
871The DMARC implementation uses the OpenDMARC library which is Copyrighted by
872The Trusted Domain Project. Portions of Exim source which use OpenDMARC
873derived code are indicated in the respective source files. The full OpenDMARC
874license is provided in the LICENSE.opendmarc file contained in the distributed
875source code.
876
877.next
9b371988 878Many people have contributed code fragments, some large, some small, that were
168e428f 879not covered by any specific licence requirements. It is assumed that the
f89d2485 880contributors are happy to see their code incorporated into Exim under the GPL.
9b371988 881.endlist
168e428f
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882
883
884
885
886
9b371988
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887. ////////////////////////////////////////////////////////////////////////////
888. ////////////////////////////////////////////////////////////////////////////
168e428f 889
f89d2485 890.chapter "How Exim receives and delivers mail" "CHID11" &&&
9b371988 891 "Receiving and delivering mail"
168e428f
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892
893
f89d2485 894.section "Overall philosophy" "SECID10"
9b371988 895.cindex "design philosophy"
168e428f
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896Exim is designed to work efficiently on systems that are permanently connected
897to the Internet and are handling a general mix of mail. In such circumstances,
898most messages can be delivered immediately. Consequently, Exim does not
899maintain independent queues of messages for specific domains or hosts, though
900it does try to send several messages in a single SMTP connection after a host
901has been down, and it also maintains per-host retry information.
902
903
f89d2485 904.section "Policy control" "SECID11"
9b371988 905.cindex "policy control" "overview"
168e428f
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906Policy controls are now an important feature of MTAs that are connected to the
907Internet. Perhaps their most important job is to stop MTAs being abused as
9b371988
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908&"open relays"& by misguided individuals who send out vast amounts of
909unsolicited junk, and want to disguise its source. Exim provides flexible
910facilities for specifying policy controls on incoming mail:
168e428f 911
9b371988
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912.ilist
913.cindex "&ACL;" "introduction"
168e428f 914Exim 4 (unlike previous versions of Exim) implements policy controls on
9b371988 915incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
168e428f
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916series of statements that may either grant or deny access. ACLs can be used at
917several places in the SMTP dialogue while receiving a message from a remote
9b371988
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918host. However, the most common places are after each RCPT command, and at the
919very end of the message. The sysadmin can specify conditions for accepting or
920rejecting individual recipients or the entire message, respectively, at these
921two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
168e428f 922error code.
9b371988
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923.next
924An ACL is also available for locally generated, non-SMTP messages. In this
168e428f 925case, the only available actions are to accept or deny the entire message.
9b371988
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926.next
927When Exim is compiled with the content-scanning extension, facilities are
168e428f
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928provided in the ACL mechanism for passing the message to external virus and/or
929spam scanning software. The result of such a scan is passed back to the ACL,
930which can then use it to decide what to do with the message.
9b371988
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931.next
932When a message has been received, either from a remote host or from the local
f89d2485 933host, but before the final acknowledgment has been sent, a locally supplied C
9b371988
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934function called &[local_scan()]& can be run to inspect the message and decide
935whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
936is accepted, the list of recipients can be modified by the function.
937.next
938Using the &[local_scan()]& mechanism is another way of calling external scanner
939software. The &%SA-Exim%& add-on package works this way. It does not require
940Exim to be compiled with the content-scanning extension.
941.next
942After a message has been accepted, a further checking mechanism is available in
943the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
944runs at the start of every delivery process.
945.endlist
946
947
948
f89d2485 949.section "User filters" "SECID12"
9b371988
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950.cindex "filter" "introduction"
951.cindex "Sieve filter"
168e428f 952In a conventional Exim configuration, users are able to run private filters by
9b371988
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953setting up appropriate &_.forward_& files in their home directories. See
954chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
955configuration needed to support this, and the separate document entitled
956&'Exim's interfaces to mail filtering'& for user details. Two different kinds
957of filtering are available:
958
959.ilist
960Sieve filters are written in the standard filtering language that is defined
168e428f 961by RFC 3028.
9b371988
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962.next
963Exim filters are written in a syntax that is unique to Exim, but which is more
168e428f 964powerful than Sieve, which it pre-dates.
9b371988 965.endlist
168e428f
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966
967User filters are run as part of the routing process, described below.
968
969
970
9b371988
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971.section "Message identification" "SECTmessiden"
972.cindex "message ids" "details of format"
973.cindex "format" "of message id"
974.cindex "id of message"
975.cindex "base62"
976.cindex "base36"
977.cindex "Darwin"
978.cindex "Cygwin"
979Every message handled by Exim is given a &'message id'& which is sixteen
168e428f 980characters long. It is divided into three parts, separated by hyphens, for
9b371988 981example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
168e428f
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982normally encoding numbers in base 62. However, in the Darwin operating
983system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
984(avoiding the use of lower case letters) is used instead, because the message
985id is used to construct file names, and the names of files in those systems are
068aaea8 986not always case-sensitive.
168e428f 987
9b371988 988.cindex "pid (process id)" "re-use of"
168e428f
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989The detail of the contents of the message id have changed as Exim has evolved.
990Earlier versions relied on the operating system not re-using a process id (pid)
991within one second. On modern operating systems, this assumption can no longer
992be made, so the algorithm had to be changed. To retain backward compatibility,
993the format of the message id was retained, which is why the following rules are
994somewhat eccentric:
995
9b371988
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996.ilist
997The first six characters of the message id are the time at which the message
168e428f
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998started to be received, to a granularity of one second. That is, this field
999contains the number of seconds since the start of the epoch (the normal Unix
1000way of representing the date and time of day).
9b371988
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1001.next
1002After the first hyphen, the next six characters are the id of the process that
168e428f 1003received the message.
9b371988
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1004.next
1005There are two different possibilities for the final two characters:
1006.olist
0a4e3112 1007.oindex "&%localhost_number%&"
9b371988 1008If &%localhost_number%& is not set, this value is the fractional part of the
168e428f
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1009time of reception, normally in units of 1/2000 of a second, but for systems
1010that must use base 36 instead of base 62 (because of case-insensitive file
1011systems), the units are 1/1000 of a second.
9b371988
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1012.next
1013If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
168e428f
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1014the fractional part of the time, which in this case is in units of 1/200
1015(1/100) of a second.
9b371988
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1016.endlist
1017.endlist
168e428f
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1018
1019After a message has been received, Exim waits for the clock to tick at the
1020appropriate resolution before proceeding, so that if another message is
1021received by the same process, or by another process with the same (re-used)
1022pid, it is guaranteed that the time will be different. In most cases, the clock
1023will already have ticked while the message was being received.
1024
1025
f89d2485 1026.section "Receiving mail" "SECID13"
9b371988
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1027.cindex "receiving mail"
1028.cindex "message" "reception"
068aaea8
PH
1029The only way Exim can receive mail from another host is using SMTP over
1030TCP/IP, in which case the sender and recipient addresses are transferred using
168e428f
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1031SMTP commands. However, from a locally running process (such as a user's MUA),
1032there are several possibilities:
1033
9b371988
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1034.ilist
1035If the process runs Exim with the &%-bm%& option, the message is read
168e428f 1036non-interactively (usually via a pipe), with the recipients taken from the
9b371988
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1037command line, or from the body of the message if &%-t%& is also used.
1038.next
1039If the process runs Exim with the &%-bS%& option, the message is also read
168e428f
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1040non-interactively, but in this case the recipients are listed at the start of
1041the message in a series of SMTP RCPT commands, terminated by a DATA
9b371988 1042command. This is so-called &"batch SMTP"& format,
168e428f
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1043but it isn't really SMTP. The SMTP commands are just another way of passing
1044envelope addresses in a non-interactive submission.
9b371988
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1045.next
1046If the process runs Exim with the &%-bs%& option, the message is read
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1047interactively, using the SMTP protocol. A two-way pipe is normally used for
1048passing data between the local process and the Exim process.
9b371988 1049This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
168e428f 1050example, the ACLs for SMTP commands are used for this form of submission.
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1051.next
1052A local process may also make a TCP/IP call to the host's loopback address
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1053(127.0.0.1) or any other of its IP addresses. When receiving messages, Exim
1054does not treat the loopback address specially. It treats all such connections
1055in the same way as connections from other hosts.
9b371988 1056.endlist
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1057
1058
f89d2485 1059.cindex "message sender, constructed by Exim"
9b371988 1060.cindex "sender" "constructed by Exim"
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1061In the three cases that do not involve TCP/IP, the sender address is
1062constructed from the login name of the user that called Exim and a default
9b371988 1063qualification domain (which can be set by the &%qualify_domain%& configuration
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1064option). For local or batch SMTP, a sender address that is passed using the
1065SMTP MAIL command is ignored. However, the system administrator may allow
9b371988 1066certain users (&"trusted users"&) to specify a different sender address
168e428f 1067unconditionally, or all users to specify certain forms of different sender
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1068address. The &%-f%& option or the SMTP MAIL command is used to specify these
1069different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1070users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
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1071users to change sender addresses.
1072
1073Messages received by either of the non-interactive mechanisms are subject to
1074checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1075(either over TCP/IP, or interacting with a local process) can be checked by a
1076number of ACLs that operate at different times during the SMTP session. Either
1077individual recipients, or the entire message, can be rejected if local policy
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1078requirements are not met. The &[local_scan()]& function (see chapter
1079&<<CHAPlocalscan>>&) is run for all incoming messages.
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1080
1081Exim can be configured not to start a delivery process when a message is
1082received; this can be unconditional, or depend on the number of incoming SMTP
1083connections or the system load. In these situations, new messages wait on the
1084queue until a queue runner process picks them up. However, in standard
1085configurations under normal conditions, delivery is started as soon as a
1086message is received.
1087
1088
1089
1090
1091
f89d2485 1092.section "Handling an incoming message" "SECID14"
9b371988
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1093.cindex "spool directory" "files that hold a message"
1094.cindex "file" "how a message is held"
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1095When Exim accepts a message, it writes two files in its spool directory. The
1096first contains the envelope information, the current status of the message, and
1097the header lines, and the second contains the body of the message. The names of
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1098the two spool files consist of the message id, followed by &`-H`& for the
1099file containing the envelope and header, and &`-D`& for the data file.
168e428f 1100
9b371988 1101.cindex "spool directory" "&_input_& sub-directory"
168e428f 1102By default all these message files are held in a single directory called
9b371988 1103&_input_& inside the general Exim spool directory. Some operating systems do
c0712871 1104not perform very well if the number of files in a directory gets large; to
9b371988 1105improve performance in such cases, the &%split_spool_directory%& option can be
168e428f 1106used. This causes Exim to split up the input files into 62 sub-directories
db9452a9 1107whose names are single letters or digits. When this is done, the queue is
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1108processed one sub-directory at a time instead of all at once, which can improve
1109overall performance even when there are not enough files in each directory to
db9452a9 1110affect file system performance.
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1111
1112The envelope information consists of the address of the message's sender and
1113the addresses of the recipients. This information is entirely separate from
1114any addresses contained in the header lines. The status of the message includes
1115a list of recipients who have already received the message. The format of the
9b371988 1116first spool file is described in chapter &<<CHAPspool>>&.
168e428f 1117
9b371988 1118.cindex "rewriting" "addresses"
168e428f 1119Address rewriting that is specified in the rewrite section of the configuration
9b371988 1120(see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
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1121both in the header lines and the envelope, at the time the message is accepted.
1122If during the course of delivery additional addresses are generated (for
1123example, via aliasing), these new addresses are rewritten as soon as they are
1124generated. At the time a message is actually delivered (transported) further
1125rewriting can take place; because this is a transport option, it can be
1126different for different forms of delivery. It is also possible to specify the
1127addition or removal of certain header lines at the time the message is
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1128delivered (see chapters &<<CHAProutergeneric>>& and
1129&<<CHAPtransportgeneric>>&).
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1130
1131
1132
f89d2485 1133.section "Life of a message" "SECID15"
9b371988
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1134.cindex "message" "life of"
1135.cindex "message" "frozen"
168e428f
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1136A message remains in the spool directory until it is completely delivered to
1137its recipients or to an error address, or until it is deleted by an
1138administrator or by the user who originally created it. In cases when delivery
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1139cannot proceed &-- for example, when a message can neither be delivered to its
1140recipients nor returned to its sender, the message is marked &"frozen"& on the
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1141spool, and no more deliveries are attempted.
1142
9b371988
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1143.cindex "frozen messages" "thawing"
1144.cindex "message" "thawing frozen"
1145An administrator can &"thaw"& such messages when the problem has been
1146corrected, and can also freeze individual messages by hand if necessary. In
1147addition, an administrator can force a delivery error, causing a bounce message
1148to be sent.
1149
0a4e3112
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1150.oindex "&%timeout_frozen_after%&"
1151.oindex "&%ignore_bounce_errors_after%&"
9b371988
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1152There are options called &%ignore_bounce_errors_after%& and
1153&%timeout_frozen_after%&, which discard frozen messages after a certain time.
068aaea8 1154The first applies only to frozen bounces, the second to any frozen messages.
168e428f 1155
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1156.cindex "message" "log file for"
1157.cindex "log" "file for each message"
168e428f 1158While Exim is working on a message, it writes information about each delivery
068aaea8 1159attempt to its main log file. This includes successful, unsuccessful, and
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1160delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1161lines are also written to a separate &'message log'& file for each message.
1162These logs are solely for the benefit of the administrator, and are normally
1163deleted along with the spool files when processing of a message is complete.
168e428f 1164The use of individual message logs can be disabled by setting
9b371988
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1165&%no_message_logs%&; this might give an improvement in performance on very busy
1166systems.
168e428f 1167
9b371988
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1168.cindex "journal file"
1169.cindex "file" "journal"
168e428f
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1170All the information Exim itself needs to set up a delivery is kept in the first
1171spool file, along with the header lines. When a successful delivery occurs, the
1172address is immediately written at the end of a journal file, whose name is the
9b371988
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1173message id followed by &`-J`&. At the end of a delivery run, if there are some
1174addresses left to be tried again later, the first spool file (the &`-H`& file)
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1175is updated to indicate which these are, and the journal file is then deleted.
1176Updating the spool file is done by writing a new file and renaming it, to
1177minimize the possibility of data loss.
1178
1179Should the system or the program crash after a successful delivery but before
1180the spool file has been updated, the journal is left lying around. The next
1181time Exim attempts to deliver the message, it reads the journal file and
1182updates the spool file before proceeding. This minimizes the chances of double
1183deliveries caused by crashes.
1184
1185
1186
9b371988
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1187.section "Processing an address for delivery" "SECTprocaddress"
1188.cindex "drivers" "definition of"
1189.cindex "router" "definition of"
1190.cindex "transport" "definition of"
1191The main delivery processing elements of Exim are called &'routers'& and
1192&'transports'&, and collectively these are known as &'drivers'&. Code for a
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1193number of them is provided in the source distribution, and compile-time options
1194specify which ones are included in the binary. Run time options specify which
1195ones are actually used for delivering messages.
1196
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1197.cindex "drivers" "instance definition"
1198Each driver that is specified in the run time configuration is an &'instance'&
168e428f 1199of that particular driver type. Multiple instances are allowed; for example,
9b371988 1200you can set up several different &(smtp)& transports, each with different
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1201option values that might specify different ports or different timeouts. Each
1202instance has its own identifying name. In what follows we will normally use the
1203instance name when discussing one particular instance (that is, one specific
1204configuration of the driver), and the generic driver name when discussing
1205the driver's features in general.
1206
9b371988 1207A &'router'& is a driver that operates on an address, either determining how
068aaea8 1208its delivery should happen, by assigning it to a specific transport, or
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1209converting the address into one or more new addresses (for example, via an
1210alias file). A router may also explicitly choose to fail an address, causing it
1211to be bounced.
1212
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1213A &'transport'& is a driver that transmits a copy of the message from Exim's
1214spool to some destination. There are two kinds of transport: for a &'local'&
168e428f 1215transport, the destination is a file or a pipe on the local host, whereas for a
9b371988 1216&'remote'& transport the destination is some other host. A message is passed
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1217to a specific transport as a result of successful routing. If a message has
1218several recipients, it may be passed to a number of different transports.
1219
9b371988 1220.cindex "preconditions" "definition of"
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1221An address is processed by passing it to each configured router instance in
1222turn, subject to certain preconditions, until a router accepts the address or
1223specifies that it should be bounced. We will describe this process in more
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1224detail shortly. First, as a simple example, we consider how each recipient
1225address in a message is processed in a small configuration of three routers.
168e428f 1226
068aaea8 1227To make this a more concrete example, it is described in terms of some actual
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1228routers, but remember, this is only an example. You can configure Exim's
1229routers in many different ways, and there may be any number of routers in a
1230configuration.
1231
1232The first router that is specified in a configuration is often one that handles
1233addresses in domains that are not recognized specially by the local host. These
1234are typically addresses for arbitrary domains on the Internet. A precondition
1235is set up which looks for the special domains known to the host (for example,
9b371988 1236its own domain name), and the router is run for addresses that do &'not'&
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1237match. Typically, this is a router that looks up domains in the DNS in order to
1238find the hosts to which this address routes. If it succeeds, the address is
068aaea8 1239assigned to a suitable SMTP transport; if it does not succeed, the router is
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1240configured to fail the address.
1241
068aaea8 1242The second router is reached only when the domain is recognized as one that
9b371988 1243&"belongs"& to the local host. This router does redirection &-- also known as
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1244aliasing and forwarding. When it generates one or more new addresses from the
1245original, each of them is routed independently from the start. Otherwise, the
1246router may cause an address to fail, or it may simply decline to handle the
1247address, in which case the address is passed to the next router.
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1248
1249The final router in many configurations is one that checks to see if the
1250address belongs to a local mailbox. The precondition may involve a check to
1251see if the local part is the name of a login account, or it may look up the
1252local part in a file or a database. If its preconditions are not met, or if
1253the router declines, we have reached the end of the routers. When this happens,
1254the address is bounced.
1255
1256
1257
f89d2485 1258.section "Processing an address for verification" "SECID16"
9b371988
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1259.cindex "router" "for verification"
1260.cindex "verifying address" "overview"
168e428f 1261As well as being used to decide how to deliver to an address, Exim's routers
9b371988 1262are also used for &'address verification'&. Verification can be requested as
168e428f 1263one of the checks to be performed in an ACL for incoming messages, on both
9b371988
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1264sender and recipient addresses, and it can be tested using the &%-bv%& and
1265&%-bvs%& command line options.
168e428f 1266
9b371988 1267When an address is being verified, the routers are run in &"verify mode"&. This
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1268does not affect the way the routers work, but it is a state that can be
1269detected. By this means, a router can be skipped or made to behave differently
1270when verifying. A common example is a configuration in which the first router
1271sends all messages to a message-scanning program, unless they have been
1272previously scanned. Thus, the first router accepts all addresses without any
9b371988 1273checking, making it useless for verifying. Normally, the &%no_verify%& option
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1274would be set for such a router, causing it to be skipped in verify mode.
1275
1276
1277
1278
9b371988
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1279.section "Running an individual router" "SECTrunindrou"
1280.cindex "router" "running details"
1281.cindex "preconditions" "checking"
1282.cindex "router" "result of running"
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1283As explained in the example above, a number of preconditions are checked before
1284running a router. If any are not met, the router is skipped, and the address is
9b371988 1285passed to the next router. When all the preconditions on a router &'are'& met,
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1286the router is run. What happens next depends on the outcome, which is one of
1287the following:
1288
9b371988
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1289.ilist
1290&'accept'&: The router accepts the address, and either assigns it to a
1291transport, or generates one or more &"child"& addresses. Processing the
1292original address ceases,
0a4e3112 1293.oindex "&%unseen%&"
9b371988 1294unless the &%unseen%& option is set on the router. This option
168e428f 1295can be used to set up multiple deliveries with different routing (for example,
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1296for keeping archive copies of messages). When &%unseen%& is set, the address is
1297passed to the next router. Normally, however, an &'accept'& return marks the
168e428f 1298end of routing.
9b371988 1299
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1300Any child addresses generated by the router are processed independently,
1301starting with the first router by default. It is possible to change this by
9b371988
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1302setting the &%redirect_router%& option to specify which router to start at for
1303child addresses. Unlike &%pass_router%& (see below) the router specified by
1304&%redirect_router%& may be anywhere in the router configuration.
1305.next
1306&'pass'&: The router recognizes the address, but cannot handle it itself. It
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1307requests that the address be passed to another router. By default the address
1308is passed to the next router, but this can be changed by setting the
9b371988 1309&%pass_router%& option. However, (unlike &%redirect_router%&) the named router
168e428f 1310must be below the current router (to avoid loops).
9b371988
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1311.next
1312&'decline'&: The router declines to accept the address because it does not
168e428f 1313recognize it at all. By default, the address is passed to the next router, but
9b371988
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1314this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1315set, all the remaining routers are skipped. In effect, &%no_more%& converts
1316&'decline'& into &'fail'&.
1317.next
1318&'fail'&: The router determines that the address should fail, and queues it for
168e428f 1319the generation of a bounce message. There is no further processing of the
9b371988
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1320original address unless &%unseen%& is set on the router.
1321.next
1322&'defer'&: The router cannot handle the address at the present time. (A
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1323database may be offline, or a DNS lookup may have timed out.) No further
1324processing of the address happens in this delivery attempt. It is tried again
1325next time the message is considered for delivery.
9b371988
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1326.next
1327&'error'&: There is some error in the router (for example, a syntax error in
168e428f 1328its configuration). The action is as for defer.
9b371988 1329.endlist
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1330
1331If an address reaches the end of the routers without having been accepted by
068aaea8 1332any of them, it is bounced as unrouteable. The default error message in this
9b371988
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1333situation is &"unrouteable address"&, but you can set your own message by
1334making use of the &%cannot_route_message%& option. This can be set for any
1335router; the value from the last router that &"saw"& the address is used.
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1336
1337Sometimes while routing you want to fail a delivery when some conditions are
1338met but others are not, instead of passing the address on for further routing.
1339You can do this by having a second router that explicitly fails the delivery
9b371988 1340when the relevant conditions are met. The &(redirect)& router has a &"fail"&
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1341facility for this purpose.
1342
1343
f89d2485 1344.section "Duplicate addresses" "SECID17"
9b371988 1345.cindex "case of local parts"
f89d2485 1346.cindex "address duplicate, discarding"
db9452a9 1347.cindex "duplicate addresses"
068aaea8
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1348Once routing is complete, Exim scans the addresses that are assigned to local
1349and remote transports, and discards any duplicates that it finds. During this
3cb1b51e 1350check, local parts are treated as case-sensitive. This happens only when
db9452a9 1351actually delivering a message; when testing routers with &%-bt%&, all the
3cb1b51e 1352routed addresses are shown.
db9452a9 1353
068aaea8 1354
168e428f 1355
9b371988 1356.section "Router preconditions" "SECTrouprecon"
f89d2485 1357.cindex "router" "preconditions, order of processing"
9b371988 1358.cindex "preconditions" "order of processing"
168e428f
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1359The preconditions that are tested for each router are listed below, in the
1360order in which they are tested. The individual configuration options are
9b371988 1361described in more detail in chapter &<<CHAProutergeneric>>&.
168e428f 1362
9b371988
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1363.ilist
1364The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
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1365the local parts handled by the router may or must have certain prefixes and/or
1366suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1367skipped. These conditions are tested first. When an affix is present, it is
1368removed from the local part before further processing, including the evaluation
1369of any other conditions.
9b371988
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1370.next
1371Routers can be designated for use only when not verifying an address, that is,
168e428f 1372only when routing it for delivery (or testing its delivery routing). If the
9b371988 1373&%verify%& option is set false, the router is skipped when Exim is verifying an
168e428f 1374address.
9b371988
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1375Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1376&%verify_recipient%&, which independently control the use of the router for
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1377sender and recipient verification. You can set these options directly if
1378you want a router to be used for only one type of verification.
5b0cf788
JH
1379Note that cutthrough delivery is classed as a recipient verification
1380for this purpose.
9b371988
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1381.next
1382If the &%address_test%& option is set false, the router is skipped when Exim is
1383run with the &%-bt%& option to test an address routing. This can be helpful
1384when the first router sends all new messages to a scanner of some sort; it
1385makes it possible to use &%-bt%& to test subsequent delivery routing without
1386having to simulate the effect of the scanner.
1387.next
1388Routers can be designated for use only when verifying an address, as
1389opposed to routing it for delivery. The &%verify_only%& option controls this.
5b0cf788 1390Again, cutthrough delibery counts as a verification.
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1391.next
1392Individual routers can be explicitly skipped when running the routers to
1393check an address given in the SMTP EXPN command (see the &%expn%& option).
1394.next
1395If the &%domains%& option is set, the domain of the address must be in the set
068aaea8 1396of domains that it defines.
9b371988 1397.next
f89d2485
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1398.vindex "&$local_part_prefix$&"
1399.vindex "&$local_part$&"
1400.vindex "&$local_part_suffix$&"
9b371988
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1401If the &%local_parts%& option is set, the local part of the address must be in
1402the set of local parts that it defines. If &%local_part_prefix%& or
1403&%local_part_suffix%& is in use, the prefix or suffix is removed from the local
168e428f 1404part before this check. If you want to do precondition tests on local parts
9b371988
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1405that include affixes, you can do so by using a &%condition%& option (see below)
1406that uses the variables &$local_part$&, &$local_part_prefix$&, and
1407&$local_part_suffix$& as necessary.
1408.next
f89d2485
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1409.vindex "&$local_user_uid$&"
1410.vindex "&$local_user_gid$&"
1411.vindex "&$home$&"
9b371988 1412If the &%check_local_user%& option is set, the local part must be the name of
068aaea8 1413an account on the local host. If this check succeeds, the uid and gid of the
9b371988
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1414local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1415user's home directory is placed in &$home$&; these values can be used in the
1416remaining preconditions.
1417.next
1418If the &%router_home_directory%& option is set, it is expanded at this point,
1419because it overrides the value of &$home$&. If this expansion were left till
1420later, the value of &$home$& as set by &%check_local_user%& would be used in
1421subsequent tests. Having two different values of &$home$& in the same router
168e428f 1422could lead to confusion.
9b371988
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1423.next
1424If the &%senders%& option is set, the envelope sender address must be in the
1425set of addresses that it defines.
1426.next
1427If the &%require_files%& option is set, the existence or non-existence of
168e428f 1428specified files is tested.
9b371988
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1429.next
1430.cindex "customizing" "precondition"
1431If the &%condition%& option is set, it is evaluated and tested. This option
1432uses an expanded string to allow you to set up your own custom preconditions.
1433Expanded strings are described in chapter &<<CHAPexpand>>&.
1434.endlist
168e428f 1435
168e428f 1436
9b371988
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1437Note that &%require_files%& comes near the end of the list, so you cannot use
1438it to check for the existence of a file in which to lookup up a domain, local
168e428f 1439part, or sender. However, as these options are all expanded, you can use the
9b371988
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1440&%exists%& expansion condition to make such tests within each condition. The
1441&%require_files%& option is intended for checking files that the router may be
168e428f 1442going to use internally, or which are needed by a specific transport (for
9b371988 1443example, &_.procmailrc_&).
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1444
1445
1446
f89d2485 1447.section "Delivery in detail" "SECID18"
9b371988 1448.cindex "delivery" "in detail"
168e428f
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1449When a message is to be delivered, the sequence of events is as follows:
1450
9b371988
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1451.ilist
1452If a system-wide filter file is specified, the message is passed to it. The
168e428f
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1453filter may add recipients to the message, replace the recipients, discard the
1454message, cause a new message to be generated, or cause the message delivery to
1455fail. The format of the system filter file is the same as for Exim user filter
9b371988
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1456files, described in the separate document entitled &'Exim's interfaces to mail
1457filtering'&.
1458.cindex "Sieve filter" "not available for system filter"
1459(&*Note*&: Sieve cannot be used for system filter files.)
1460
1461Some additional features are available in system filters &-- see chapter
1462&<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
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1463filter only once per delivery attempt, however many recipients it has. However,
1464if there are several delivery attempts because one or more addresses could not
1465be immediately delivered, the system filter is run each time. The filter
9b371988 1466condition &%first_delivery%& can be used to detect the first run of the system
168e428f 1467filter.
9b371988
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1468.next
1469Each recipient address is offered to each configured router in turn, subject to
1470its preconditions, until one is able to handle it. If no router can handle the
1471address, that is, if they all decline, the address is failed. Because routers
1472can be targeted at particular domains, several locally handled domains can be
1473processed entirely independently of each other.
1474.next
1475.cindex "routing" "loops in"
1476.cindex "loop" "while routing"
1477A router that accepts an address may assign it to a local or a remote
1478transport. However, the transport is not run at this time. Instead, the address
1479is placed on a list for the particular transport, which will be run later.
068aaea8
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1480Alternatively, the router may generate one or more new addresses (typically
1481from alias, forward, or filter files). New addresses are fed back into this
1482process from the top, but in order to avoid loops, a router ignores any address
1483which has an identically-named ancestor that was processed by itself.
9b371988
PH
1484.next
1485When all the routing has been done, addresses that have been successfully
168e428f
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1486handled are passed to their assigned transports. When local transports are
1487doing real local deliveries, they handle only one address at a time, but if a
1488local transport is being used as a pseudo-remote transport (for example, to
1489collect batched SMTP messages for transmission by some other means) multiple
1490addresses can be handled. Remote transports can always handle more than one
1491address at a time, but can be configured not to do so, or to restrict multiple
1492addresses to the same domain.
9b371988
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1493.next
1494Each local delivery to a file or a pipe runs in a separate process under a
168e428f
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1495non-privileged uid, and these deliveries are run one at a time. Remote
1496deliveries also run in separate processes, normally under a uid that is private
9b371988 1497to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
168e428f 1498run in parallel. The maximum number of simultaneous remote deliveries for any
9b371988 1499one message is set by the &%remote_max_parallel%& option.
168e428f
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1500The order in which deliveries are done is not defined, except that all local
1501deliveries happen before any remote deliveries.
9b371988
PH
1502.next
1503.cindex "queue runner"
168e428f
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1504When it encounters a local delivery during a queue run, Exim checks its retry
1505database to see if there has been a previous temporary delivery failure for the
1506address before running the local transport. If there was a previous failure,
1507Exim does not attempt a new delivery until the retry time for the address is
1508reached. However, this happens only for delivery attempts that are part of a
1509queue run. Local deliveries are always attempted when delivery immediately
1510follows message reception, even if retry times are set for them. This makes for
1511better behaviour if one particular message is causing problems (for example,
1512causing quota overflow, or provoking an error in a filter file).
9b371988
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1513.next
1514.cindex "delivery" "retry in remote transports"
168e428f
PH
1515Remote transports do their own retry handling, since an address may be
1516deliverable to one of a number of hosts, each of which may have a different
1517retry time. If there have been previous temporary failures and no host has
1518reached its retry time, no delivery is attempted, whether in a queue run or
9b371988
PH
1519not. See chapter &<<CHAPretry>>& for details of retry strategies.
1520.next
1521If there were any permanent errors, a bounce message is returned to an
168e428f
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1522appropriate address (the sender in the common case), with details of the error
1523for each failing address. Exim can be configured to send copies of bounce
1524messages to other addresses.
9b371988
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1525.next
1526.cindex "delivery" "deferral"
168e428f
PH
1527If one or more addresses suffered a temporary failure, the message is left on
1528the queue, to be tried again later. Delivery of these addresses is said to be
9b371988
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1529&'deferred'&.
1530.next
1531When all the recipient addresses have either been delivered or bounced,
168e428f
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1532handling of the message is complete. The spool files and message log are
1533deleted, though the message log can optionally be preserved if required.
9b371988 1534.endlist
168e428f
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1535
1536
1537
1538
f89d2485 1539.section "Retry mechanism" "SECID19"
9b371988
PH
1540.cindex "delivery" "retry mechanism"
1541.cindex "retry" "description of mechanism"
1542.cindex "queue runner"
168e428f
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1543Exim's mechanism for retrying messages that fail to get delivered at the first
1544attempt is the queue runner process. You must either run an Exim daemon that
9b371988
PH
1545uses the &%-q%& option with a time interval to start queue runners at regular
1546intervals, or use some other means (such as &'cron'&) to start them. If you do
168e428f
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1547not arrange for queue runners to be run, messages that fail temporarily at the
1548first attempt will remain on your queue for ever. A queue runner process works
068aaea8 1549its way through the queue, one message at a time, trying each delivery that has
168e428f
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1550passed its retry time.
1551You can run several queue runners at once.
1552
1553Exim uses a set of configured rules to determine when next to retry the failing
9b371988
PH
1554address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1555should give up trying to deliver to the address, at which point it generates a
1556bounce message. If no retry rules are set for a particular host, address, and
1557error combination, no retries are attempted, and temporary errors are treated
1558as permanent.
168e428f
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1559
1560
1561
f89d2485 1562.section "Temporary delivery failure" "SECID20"
9b371988 1563.cindex "delivery" "temporary failure"
168e428f
PH
1564There are many reasons why a message may not be immediately deliverable to a
1565particular address. Failure to connect to a remote machine (because it, or the
1566connection to it, is down) is one of the most common. Temporary failures may be
1567detected during routing as well as during the transport stage of delivery.
1568Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1569is on a file system where the user is over quota. Exim can be configured to
1570impose its own quotas on local mailboxes; where system quotas are set they will
1571also apply.
1572
1573If a host is unreachable for a period of time, a number of messages may be
1574waiting for it by the time it recovers, and sending them in a single SMTP
1575connection is clearly beneficial. Whenever a delivery to a remote host is
1576deferred,
9b371988 1577.cindex "hints database"
168e428f
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1578Exim makes a note in its hints database, and whenever a successful
1579SMTP delivery has happened, it looks to see if any other messages are waiting
1580for the same host. If any are found, they are sent over the same SMTP
1581connection, subject to a configuration limit as to the maximum number in any
1582one connection.
168e428f
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1583
1584
1585
f89d2485 1586.section "Permanent delivery failure" "SECID21"
9b371988
PH
1587.cindex "delivery" "permanent failure"
1588.cindex "bounce message" "when generated"
168e428f
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1589When a message cannot be delivered to some or all of its intended recipients, a
1590bounce message is generated. Temporary delivery failures turn into permanent
1591errors when their timeout expires. All the addresses that fail in a given
1592delivery attempt are listed in a single message. If the original message has
1593many recipients, it is possible for some addresses to fail in one delivery
1594attempt and others to fail subsequently, giving rise to more than one bounce
1595message. The wording of bounce messages can be customized by the administrator.
9b371988 1596See chapter &<<CHAPemsgcust>>& for details.
168e428f 1597
9b371988
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1598.cindex "&'X-Failed-Recipients:'& header line"
1599Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
168e428f
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1600failed addresses, for the benefit of programs that try to analyse such messages
1601automatically.
1602
9b371988 1603.cindex "bounce message" "recipient of"
168e428f
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1604A bounce message is normally sent to the sender of the original message, as
1605obtained from the message's envelope. For incoming SMTP messages, this is the
9b371988
PH
1606address given in the MAIL command. However, when an address is expanded via a
1607forward or alias file, an alternative address can be specified for delivery
1608failures of the generated addresses. For a mailing list expansion (see section
1609&<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1610of the list.
168e428f
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1611
1612
1613
f89d2485 1614.section "Failures to deliver bounce messages" "SECID22"
9b371988 1615.cindex "bounce message" "failure to deliver"
168e428f
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1616If a bounce message (either locally generated or received from a remote host)
1617itself suffers a permanent delivery failure, the message is left on the queue,
1618but it is frozen, awaiting the attention of an administrator. There are options
068aaea8 1619that can be used to make Exim discard such failed messages, or to keep them
9b371988
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1620for only a short time (see &%timeout_frozen_after%& and
1621&%ignore_bounce_errors_after%&).
168e428f
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1622
1623
1624
1625
1626
9b371988
PH
1627. ////////////////////////////////////////////////////////////////////////////
1628. ////////////////////////////////////////////////////////////////////////////
168e428f 1629
f89d2485 1630.chapter "Building and installing Exim" "CHID3"
4f578862 1631.scindex IIDbuex "building Exim"
168e428f 1632
f89d2485
PH
1633.section "Unpacking" "SECID23"
1634Exim is distributed as a gzipped or bzipped tar file which, when unpacked,
168e428f 1635creates a directory with the name of the current release (for example,
2aee48d6 1636&_exim-&version()_&) into which the following files are placed:
9b371988
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1637
1638.table2 140pt
f89d2485
PH
1639.irow &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1640.irow &_CHANGES_& "contains a reference to where changes are &&&
1641 documented"
1642.irow &_LICENCE_& "the GNU General Public Licence"
1643.irow &_Makefile_& "top-level make file"
1644.irow &_NOTICE_& "conditions for the use of Exim"
1645.irow &_README_& "list of files, directories and simple build &&&
1646 instructions"
9b371988
PH
1647.endtable
1648
1649Other files whose names begin with &_README_& may also be present. The
168e428f
PH
1650following subdirectories are created:
1651
9b371988 1652.table2 140pt
f89d2485
PH
1653.irow &_Local_& "an empty directory for local configuration files"
1654.irow &_OS_& "OS-specific files"
1655.irow &_doc_& "documentation files"
1656.irow &_exim_monitor_& "source files for the Exim monitor"
1657.irow &_scripts_& "scripts used in the build process"
1658.irow &_src_& "remaining source files"
1659.irow &_util_& "independent utilities"
9b371988
PH
1660.endtable
1661
1662The main utility programs are contained in the &_src_& directory, and are built
1663with the Exim binary. The &_util_& directory contains a few optional scripts
168e428f
PH
1664that may be useful to some sites.
1665
1666
f89d2485 1667.section "Multiple machine architectures and operating systems" "SECID24"
9b371988 1668.cindex "building Exim" "multiple OS/architectures"
168e428f
PH
1669The building process for Exim is arranged to make it easy to build binaries for
1670a number of different architectures and operating systems from the same set of
9b371988
PH
1671source files. Compilation does not take place in the &_src_& directory.
1672Instead, a &'build directory'& is created for each architecture and operating
1673system.
1674.cindex "symbolic link" "to build directory"
168e428f 1675Symbolic links to the sources are installed in this directory, which is where
9b371988
PH
1676the actual building takes place. In most cases, Exim can discover the machine
1677architecture and operating system for itself, but the defaults can be
1678overridden if necessary.
168e428f 1679
168e428f 1680
8473d4ee 1681.section "PCRE library" "SECTpcre"
210f147e
NM
1682.cindex "PCRE library"
1683Exim no longer has an embedded PCRE library as the vast majority of
1684modern systems include PCRE as a system library, although you may need
1685to install the PCRE or PCRE development package for your operating
1686system. If your system has a normal PCRE installation the Exim build
1687process will need no further configuration. If the library or the
6a6084f8
PP
1688headers are in an unusual location you will need to either set the PCRE_LIBS
1689and INCLUDE directives appropriately,
1690or set PCRE_CONFIG=yes to use the installed &(pcre-config)& command.
1691If your operating system has no
210f147e
NM
1692PCRE support then you will need to obtain and build the current PCRE
1693from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/).
6a6084f8 1694More information on PCRE is available at &url(http://www.pcre.org/).
210f147e 1695
9b371988
PH
1696.section "DBM libraries" "SECTdb"
1697.cindex "DBM libraries" "discussion of"
1698.cindex "hints database" "DBM files used for"
168e428f
PH
1699Even if you do not use any DBM files in your configuration, Exim still needs a
1700DBM library in order to operate, because it uses indexed files for its hints
1701databases. Unfortunately, there are a number of DBM libraries in existence, and
1702different operating systems often have different ones installed.
1703
9b371988 1704.cindex "Solaris" "DBM library for"
f89d2485
PH
1705.cindex "IRIX, DBM library for"
1706.cindex "BSD, DBM library for"
1707.cindex "Linux, DBM library for"
168e428f
PH
1708If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1709Linux distribution, the DBM configuration should happen automatically, and you
1710may be able to ignore this section. Otherwise, you may have to learn more than
1711you would like about DBM libraries from what follows.
1712
9b371988 1713.cindex "&'ndbm'& DBM library"
168e428f 1714Licensed versions of Unix normally contain a library of DBM functions operating
9b371988 1715via the &'ndbm'& interface, and this is what Exim expects by default. Free
168e428f
PH
1716versions of Unix seem to vary in what they contain as standard. In particular,
1717some early versions of Linux have no default DBM library, and different
1718distributors have chosen to bundle different libraries with their packaged
f89d2485 1719versions. However, the more recent releases seem to have standardized on the
168e428f
PH
1720Berkeley DB library.
1721
1722Different DBM libraries have different conventions for naming the files they
9b371988 1723use. When a program opens a file called &_dbmfile_&, there are several
168e428f
PH
1724possibilities:
1725
9b371988
PH
1726.olist
1727A traditional &'ndbm'& implementation, such as that supplied as part of
1728Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1729.next
1730.cindex "&'gdbm'& DBM library"
1731The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
168e428f 1732compatibility interface it makes two different hard links to it with names
9b371988 1733&_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
168e428f 1734file name is used unmodified.
9b371988
PH
1735.next
1736.cindex "Berkeley DB library"
1737The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1738operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1739programmer exactly the same as the traditional &'ndbm'& implementation.
1740.next
1741If the Berkeley package is used in its native mode, it operates on a single
1742file called &_dbmfile_&; the programmer's interface is somewhat different to
1743the traditional &'ndbm'& interface.
1744.next
1745To complicate things further, there are several very different versions of the
168e428f 1746Berkeley DB package. Version 1.85 was stable for a very long time, releases
9b371988
PH
17472.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1748numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
168e428f 1749versions of Berkeley DB can be obtained from
9b371988
PH
1750&url(http://www.sleepycat.com/).
1751.next
1752.cindex "&'tdb'& DBM library"
1753Yet another DBM library, called &'tdb'&, is available from
1754&url(http://download.sourceforge.net/tdb). It has its own interface, and also
1755operates on a single file.
1756.endlist
1757
1758.cindex "USE_DB"
1759.cindex "DBM libraries" "configuration for building"
168e428f
PH
1760Exim and its utilities can be compiled to use any of these interfaces. In order
1761to use any version of the Berkeley DB package in native mode, you must set
1762USE_DB in an appropriate configuration file (typically
9b371988
PH
1763&_Local/Makefile_&). For example:
1764.code
1765USE_DB=yes
1766.endd
168e428f
PH
1767Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1768error is diagnosed if you set more than one of these.
1769
1770At the lowest level, the build-time configuration sets none of these options,
1771thereby assuming an interface of type (1). However, some operating system
1772configuration files (for example, those for the BSD operating systems and
1773Linux) assume type (4) by setting USE_DB as their default, and the
1774configuration files for Cygwin set USE_GDBM. Anything you set in
9b371988 1775&_Local/Makefile_&, however, overrides these system defaults.
168e428f
PH
1776
1777As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1778necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1779in one of these lines:
9b371988
PH
1780.code
1781DBMLIB = -ldb
1782DBMLIB = -ltdb
1783.endd
168e428f
PH
1784Settings like that will work if the DBM library is installed in the standard
1785place. Sometimes it is not, and the library's header file may also not be in
1786the default path. You may need to set INCLUDE to specify where the header
1787file is, and to specify the path to the library more fully in DBMLIB, as in
1788this example:
9b371988
PH
1789.code
1790INCLUDE=-I/usr/local/include/db-4.1
1791DBMLIB=/usr/local/lib/db-4.1/libdb.a
1792.endd
168e428f 1793There is further detailed discussion about the various DBM libraries in the
9b371988 1794file &_doc/dbm.discuss.txt_& in the Exim distribution.
168e428f
PH
1795
1796
1797
f89d2485 1798.section "Pre-building configuration" "SECID25"
9b371988
PH
1799.cindex "building Exim" "pre-building configuration"
1800.cindex "configuration for building Exim"
1801.cindex "&_Local/Makefile_&"
1802.cindex "&_src/EDITME_&"
168e428f
PH
1803Before building Exim, a local configuration file that specifies options
1804independent of any operating system has to be created with the name
9b371988
PH
1805&_Local/Makefile_&. A template for this file is supplied as the file
1806&_src/EDITME_&, and it contains full descriptions of all the option settings
168e428f
PH
1807therein. These descriptions are therefore not repeated here. If you are
1808building Exim for the first time, the simplest thing to do is to copy
9b371988 1809&_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
168e428f
PH
1810
1811There are three settings that you must supply, because Exim will not build
1812without them. They are the location of the run time configuration file
1813(CONFIGURE_FILE), the directory in which Exim binaries will be installed
1814(BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1815maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1816a colon-separated list of file names; Exim uses the first of them that exists.
1817
1818There are a few other parameters that can be specified either at build time or
1819at run time, to enable the same binary to be used on a number of different
1820machines. However, if the locations of Exim's spool directory and log file
1821directory (if not within the spool directory) are fixed, it is recommended that
9b371988 1822you specify them in &_Local/Makefile_& instead of at run time, so that errors
168e428f
PH
1823detected early in Exim's execution (such as a malformed configuration file) can
1824be logged.
1825
9b371988 1826.cindex "content scanning" "specifying at build time"
068aaea8 1827Exim's interfaces for calling virus and spam scanning software directly from
168e428f
PH
1828access control lists are not compiled by default. If you want to include these
1829facilities, you need to set
9b371988
PH
1830.code
1831WITH_CONTENT_SCAN=yes
1832.endd
1833in your &_Local/Makefile_&. For details of the facilities themselves, see
1834chapter &<<CHAPexiscan>>&.
168e428f
PH
1835
1836
9b371988 1837.cindex "&_Local/eximon.conf_&"
3cb1b51e 1838.cindex "&_exim_monitor/EDITME_&"
168e428f 1839If you are going to build the Exim monitor, a similar configuration process is
9b371988
PH
1840required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1841your installation and saved under the name &_Local/eximon.conf_&. If you are
1842happy with the default settings described in &_exim_monitor/EDITME_&,
1843&_Local/eximon.conf_& can be empty, but it must exist.
168e428f
PH
1844
1845This is all the configuration that is needed in straightforward cases for known
1846operating systems. However, the building process is set up so that it is easy
1847to override options that are set by default or by operating-system-specific
1848configuration files, for example to change the name of the C compiler, which
9b371988
PH
1849defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1850do this.
168e428f
PH
1851
1852
1853
f89d2485 1854.section "Support for iconv()" "SECID26"
9b371988
PH
1855.cindex "&[iconv()]& support"
1856.cindex "RFC 2047"
168e428f
PH
1857The contents of header lines in messages may be encoded according to the rules
1858described RFC 2047. This makes it possible to transmit characters that are not
1859in the ASCII character set, and to label them as being in a particular
9b371988 1860character set. When Exim is inspecting header lines by means of the &%$h_%&
168e428f
PH
1861mechanism, it decodes them, and translates them into a specified character set
1862(default ISO-8859-1). The translation is possible only if the operating system
9b371988
PH
1863supports the &[iconv()]& function.
1864
1865However, some of the operating systems that supply &[iconv()]& do not support
1866very many conversions. The GNU &%libiconv%& library (available from
1867&url(http://www.gnu.org/software/libiconv/)) can be installed on such
1868systems to remedy this deficiency, as well as on systems that do not supply
1869&[iconv()]& at all. After installing &%libiconv%&, you should add
1870.code
1871HAVE_ICONV=yes
1872.endd
1873to your &_Local/Makefile_& and rebuild Exim.
1874
1875
1876
1877.section "Including TLS/SSL encryption support" "SECTinctlsssl"
1878.cindex "TLS" "including support for TLS"
1879.cindex "encryption" "including support for"
1880.cindex "SUPPORT_TLS"
1881.cindex "OpenSSL" "building Exim with"
1882.cindex "GnuTLS" "building Exim with"
168e428f
PH
1883Exim can be built to support encrypted SMTP connections, using the STARTTLS
1884command as per RFC 2487. It can also support legacy clients that expect to
1885start a TLS session immediately on connection to a non-standard port (see the
9b371988 1886&%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
168e428f
PH
1887line option).
1888
1889If you want to build Exim with TLS support, you must first install either the
1890OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1891implementing SSL.
1892
1893If OpenSSL is installed, you should set
9b371988
PH
1894.code
1895SUPPORT_TLS=yes
1896TLS_LIBS=-lssl -lcrypto
1897.endd
1898in &_Local/Makefile_&. You may also need to specify the locations of the
168e428f 1899OpenSSL library and include files. For example:
9b371988
PH
1900.code
1901SUPPORT_TLS=yes
1902TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1903TLS_INCLUDE=-I/usr/local/openssl/include/
1904.endd
7e6a8985
PP
1905.cindex "pkg-config" "OpenSSL"
1906If you have &'pkg-config'& available, then instead you can just use:
1907.code
1908SUPPORT_TLS=yes
1909USE_OPENSSL_PC=openssl
1910.endd
9b371988 1911.cindex "USE_GNUTLS"
168e428f 1912If GnuTLS is installed, you should set
9b371988
PH
1913.code
1914SUPPORT_TLS=yes
1915USE_GNUTLS=yes
1916TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1917.endd
1918in &_Local/Makefile_&, and again you may need to specify the locations of the
168e428f 1919library and include files. For example:
9b371988
PH
1920.code
1921SUPPORT_TLS=yes
1922USE_GNUTLS=yes
1923TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1924TLS_INCLUDE=-I/usr/gnu/include
1925.endd
7e6a8985
PP
1926.cindex "pkg-config" "GnuTLS"
1927If you have &'pkg-config'& available, then instead you can just use:
1928.code
1929SUPPORT_TLS=yes
1930USE_GNUTLS=yes
1931USE_GNUTLS_PC=gnutls
1932.endd
7e6a8985 1933
168e428f 1934You do not need to set TLS_INCLUDE if the relevant directory is already
9b371988
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1935specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1936given in chapter &<<CHAPTLS>>&.
168e428f
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1937
1938
1939
1940
b52ed2b3
NM
1941.section "Use of tcpwrappers" "SECID27"
1942
f89d2485 1943.cindex "tcpwrappers, building Exim to support"
9b371988 1944.cindex "USE_TCP_WRAPPERS"
5dc43717
JJ
1945.cindex "TCP_WRAPPERS_DAEMON_NAME"
1946.cindex "tcp_wrappers_daemon_name"
9b371988
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1947Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1948SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
168e428f 1949alternative to Exim's own checking facilities for installations that are
9b371988
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1950already making use of &'tcpwrappers'& for other purposes. To do this, you
1951should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1952&_tcpd.h_& to be available at compile time, and also ensure that the library
1953&_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1954EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1955you might have
1956.code
1957USE_TCP_WRAPPERS=yes
1958CFLAGS=-O -I/usr/local/include
1959EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1960.endd
5dc43717
JJ
1961in &_Local/Makefile_&. The daemon name to use in the &'tcpwrappers'& control
1962files is &"exim"&. For example, the line
9b371988
PH
1963.code
1964exim : LOCAL 192.168.1. .friendly.domain.example
1965.endd
1966in your &_/etc/hosts.allow_& file allows connections from the local host, from
1967the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&.
5dc43717
JJ
1968All other connections are denied. The daemon name used by &'tcpwrappers'&
1969can be changed at build time by setting TCP_WRAPPERS_DAEMON_NAME in
a543079f 1970&_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the
5dc43717 1971configure file. Consult the &'tcpwrappers'& documentation for
168e428f 1972further details.
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1973
1974
f89d2485 1975.section "Including support for IPv6" "SECID28"
9b371988 1976.cindex "IPv6" "including support for"
168e428f 1977Exim contains code for use on systems that have IPv6 support. Setting
9b371988 1978&`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
168e428f
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1979it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1980where the IPv6 support is not fully integrated into the normal include and
1981library files.
1982
1983Two different types of DNS record for handling IPv6 addresses have been
f89d2485 1984defined. AAAA records (analogous to A records for IPv4) are in use, and are
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1985currently seen as the mainstream. Another record type called A6 was proposed
1986as better than AAAA because it had more flexibility. However, it was felt to be
9b371988 1987over-complex, and its status was reduced to &"experimental"&. It is not known
168e428f 1988if anyone is actually using A6 records. Exim has support for A6 records, but
9b371988 1989this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
168e428f
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1990support has not been tested for some time.
1991
1992
1993
0a349494
PP
1994.section "Dynamically loaded lookup module support" "SECTdynamicmodules"
1995.cindex "lookup modules"
1996.cindex "dynamic modules"
1997.cindex ".so building"
1998On some platforms, Exim supports not compiling all lookup types directly into
1999the main binary, instead putting some into external modules which can be loaded
2000on demand.
2001This permits packagers to build Exim with support for lookups with extensive
2002library dependencies without requiring all users to install all of those
2003dependencies.
2004Most, but not all, lookup types can be built this way.
2005
2006Set &`LOOKUP_MODULE_DIR`& to the directory into which the modules will be
2007installed; Exim will only load modules from that directory, as a security
2008measure. You will need to set &`CFLAGS_DYNAMIC`& if not already defined
2009for your OS; see &_OS/Makefile-Linux_& for an example.
2010Some other requirements for adjusting &`EXTRALIBS`& may also be necessary,
2011see &_src/EDITME_& for details.
2012
2013Then, for each module to be loaded dynamically, define the relevant
2014&`LOOKUP_`&<&'lookup_type'&> flags to have the value "2" instead of "yes".
2015For example, this will build in lsearch but load sqlite and mysql support
2016on demand:
2017.code
2018LOOKUP_LSEARCH=yes
2019LOOKUP_SQLITE=2
2020LOOKUP_MYSQL=2
2021.endd
5d758a46 2022
0a349494 2023
f89d2485 2024.section "The building process" "SECID29"
9b371988
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2025.cindex "build directory"
2026Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
2027created, run &'make'& at the top level. It determines the architecture and
168e428f
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2028operating system types, and creates a build directory if one does not exist.
2029For example, on a Sun system running Solaris 8, the directory
9b371988
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2030&_build-SunOS5-5.8-sparc_& is created.
2031.cindex "symbolic link" "to source files"
168e428f
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2032Symbolic links to relevant source files are installed in the build directory.
2033
9b371988 2034&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
168e428f
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2035building process fails if it is set.
2036
9b371988 2037If this is the first time &'make'& has been run, it calls a script that builds
168e428f 2038a make file inside the build directory, using the configuration files from the
9b371988
PH
2039&_Local_& directory. The new make file is then passed to another instance of
2040&'make'&. This does the real work, building a number of utility scripts, and
168e428f 2041then compiling and linking the binaries for the Exim monitor (if configured), a
9b371988
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2042number of utility programs, and finally Exim itself. The command &`make
2043makefile`& can be used to force a rebuild of the make file in the build
168e428f
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2044directory, should this ever be necessary.
2045
2046If you have problems building Exim, check for any comments there may be in the
9b371988 2047&_README_& file concerning your operating system, and also take a look at the
168e428f
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2048FAQ, where some common problems are covered.
2049
2050
2051
f89d2485 2052.section 'Output from &"make"&' "SECID283"
9b371988 2053The output produced by the &'make'& process for compile lines is often very
068aaea8
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2054unreadable, because these lines can be very long. For this reason, the normal
2055output is suppressed by default, and instead output similar to that which
2056appears when compiling the 2.6 Linux kernel is generated: just a short line for
2057each module that is being compiled or linked. However, it is still possible to
9b371988
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2058get the full output, by calling &'make'& like this:
2059.code
2060FULLECHO='' make -e
2061.endd
2062The value of FULLECHO defaults to &"@"&, the flag character that suppresses
2063command reflection in &'make'&. When you ask for the full output, it is
3cb1b51e 2064given in addition to the short output.
068aaea8
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2065
2066
2067
9b371988 2068.section "Overriding build-time options for Exim" "SECToverride"
f89d2485 2069.cindex "build-time options, overriding"
168e428f
PH
2070The main make file that is created at the beginning of the building process
2071consists of the concatenation of a number of files which set configuration
9b371988 2072values, followed by a fixed set of &'make'& instructions. If a value is set
168e428f
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2073more than once, the last setting overrides any previous ones. This provides a
2074convenient way of overriding defaults. The files that are concatenated are, in
2075order:
9b371988
PH
2076.display
2077&_OS/Makefile-Default_&
2078&_OS/Makefile-_&<&'ostype'&>
2079&_Local/Makefile_&
2080&_Local/Makefile-_&<&'ostype'&>
2081&_Local/Makefile-_&<&'archtype'&>
2082&_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
2083&_OS/Makefile-Base_&
2084.endd
2085.cindex "&_Local/Makefile_&"
2086.cindex "building Exim" "operating system type"
2087.cindex "building Exim" "architecture type"
2088where <&'ostype'&> is the operating system type and <&'archtype'&> is the
2089architecture type. &_Local/Makefile_& is required to exist, and the building
2090process fails if it is absent. The other three &_Local_& files are optional,
168e428f
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2091and are often not needed.
2092
9b371988
PH
2093The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
2094called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
168e428f
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2095the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
2096values are used, thereby providing a means of forcing particular settings.
9b371988 2097Otherwise, the scripts try to get values from the &%uname%& command. If this
168e428f 2098fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
9b371988 2099of &'ad hoc'& transformations are then applied, to produce the standard names
168e428f
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2100that Exim expects. You can run these scripts directly from the shell in order
2101to find out what values are being used on your system.
2102
2103
9b371988 2104&_OS/Makefile-Default_& contains comments about the variables that are set
168e428f
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2105therein. Some (but not all) are mentioned below. If there is something that
2106needs changing, review the contents of this file and the contents of the make
9b371988 2107file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
168e428f
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2108default values are.
2109
2110
9b371988
PH
2111.cindex "building Exim" "overriding default settings"
2112If you need to change any of the values that are set in &_OS/Makefile-Default_&
2113or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
168e428f 2114need to change the original files. Instead, you should make the changes by
9b371988
PH
2115putting the new values in an appropriate &_Local_& file. For example,
2116.cindex "Tru64-Unix build-time settings"
168e428f
PH
2117when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2118formerly DEC-OSF1) operating system, it is necessary to specify that the C
9b371988
PH
2119compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2120called with the option &%-std1%&, to make it recognize some of the features of
168e428f 2121Standard C that Exim uses. (Most other compilers recognize Standard C by
9b371988 2122default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
168e428f 2123containing the lines
9b371988
PH
2124.code
2125CC=cc
2126CFLAGS=-std1
2127.endd
168e428f 2128If you are compiling for just one operating system, it may be easier to put
9b371988 2129these lines directly into &_Local/Makefile_&.
168e428f
PH
2130
2131Keeping all your local configuration settings separate from the distributed
2132files makes it easy to transfer them to new versions of Exim simply by copying
9b371988 2133the contents of the &_Local_& directory.
168e428f
PH
2134
2135
9b371988
PH
2136.cindex "NIS lookup type" "including support for"
2137.cindex "NIS+ lookup type" "including support for"
2138.cindex "LDAP" "including support for"
2139.cindex "lookup" "inclusion in binary"
168e428f
PH
2140Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2141lookup, but not all systems have these components installed, so the default is
2142not to include the relevant code in the binary. All the different kinds of file
2143and database lookup that Exim supports are implemented as separate code modules
2144which are included only if the relevant compile-time options are set. In the
9b371988
PH
2145case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2146.code
2147LOOKUP_LDAP=yes
2148LOOKUP_NIS=yes
2149LOOKUP_NISPLUS=yes
2150.endd
168e428f 2151and similar settings apply to the other lookup types. They are all listed in
9b371988 2152&_src/EDITME_&. In many cases the relevant include files and interface
168e428f 2153libraries need to be installed before compiling Exim.
9b371988 2154.cindex "cdb" "including support for"
068aaea8
PH
2155However, there are some optional lookup types (such as cdb) for which
2156the code is entirely contained within Exim, and no external include
168e428f
PH
2157files or libraries are required. When a lookup type is not included in the
2158binary, attempts to configure Exim to use it cause run time configuration
2159errors.
2160
7e6a8985
PP
2161.cindex "pkg-config" "lookups"
2162.cindex "pkg-config" "authenticators"
252e0c7b
PP
2163Many systems now use a tool called &'pkg-config'& to encapsulate information
2164about how to compile against a library; Exim has some initial support for
2165being able to use pkg-config for lookups and authenticators. For any given
2166makefile variable which starts &`LOOKUP_`& or &`AUTH_`&, you can add a new
2167variable with the &`_PC`& suffix in the name and assign as the value the
2168name of the package to be queried. The results of querying via the
2169&'pkg-config'& command will be added to the appropriate Makefile variables
2170with &`+=`& directives, so your version of &'make'& will need to support that
2171syntax. For instance:
2172.code
2173LOOKUP_SQLITE=yes
2174LOOKUP_SQLITE_PC=sqlite3
2175AUTH_GSASL=yes
2176AUTH_GSASL_PC=libgsasl
2177AUTH_HEIMDAL_GSSAPI=yes
2178AUTH_HEIMDAL_GSSAPI_PC=heimdal-gssapi
2179.endd
252e0c7b 2180
9b371988 2181.cindex "Perl" "including support for"
168e428f
PH
2182Exim can be linked with an embedded Perl interpreter, allowing Perl
2183subroutines to be called during string expansion. To enable this facility,
9b371988
PH
2184.code
2185EXIM_PERL=perl.o
2186.endd
2187must be defined in &_Local/Makefile_&. Details of this facility are given in
2188chapter &<<CHAPperl>>&.
168e428f 2189
f89d2485 2190.cindex "X11 libraries, location of"
168e428f 2191The location of the X11 libraries is something that varies a lot between
068aaea8 2192operating systems, and there may be different versions of X11 to cope
168e428f
PH
2193with. Exim itself makes no use of X11, but if you are compiling the Exim
2194monitor, the X11 libraries must be available.
9b371988
PH
2195The following three variables are set in &_OS/Makefile-Default_&:
2196.code
2197X11=/usr/X11R6
2198XINCLUDE=-I$(X11)/include
2199XLFLAGS=-L$(X11)/lib
2200.endd
168e428f 2201These are overridden in some of the operating-system configuration files. For
9b371988
PH
2202example, in &_OS/Makefile-SunOS5_& there is
2203.code
2204X11=/usr/openwin
2205XINCLUDE=-I$(X11)/include
2206XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2207.endd
168e428f
PH
2208If you need to override the default setting for your operating system, place a
2209definition of all three of these variables into your
9b371988 2210&_Local/Makefile-<ostype>_& file.
168e428f 2211
9b371988 2212.cindex "EXTRALIBS"
168e428f
PH
2213If you need to add any extra libraries to the link steps, these can be put in a
2214variable called EXTRALIBS, which appears in all the link commands, but by
2215default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2216command for linking the main Exim binary, and not for any associated utilities.
2217
9b371988 2218.cindex "DBM libraries" "configuration for building"
168e428f 2219There is also DBMLIB, which appears in the link commands for binaries that
9b371988 2220use DBM functions (see also section &<<SECTdb>>&). Finally, there is
168e428f
PH
2221EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2222binary, and which can be used, for example, to include additional X11
2223libraries.
2224
9b371988 2225.cindex "configuration file" "editing"
168e428f
PH
2226The make file copes with rebuilding Exim correctly if any of the configuration
2227files are edited. However, if an optional configuration file is deleted, it is
9b371988
PH
2228necessary to touch the associated non-optional file (that is,
2229&_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
168e428f
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2230
2231
f89d2485 2232.section "OS-specific header files" "SECID30"
9b371988
PH
2233.cindex "&_os.h_&"
2234.cindex "building Exim" "OS-specific C header files"
2235The &_OS_& directory contains a number of files with names of the form
2236&_os.h-<ostype>_&. These are system-specific C header files that should not
168e428f 2237normally need to be changed. There is a list of macro settings that are
9b371988 2238recognized in the file &_OS/os.configuring_&, which should be consulted if you
168e428f
PH
2239are porting Exim to a new operating system.
2240
2241
2242
f89d2485
PH
2243.section "Overriding build-time options for the monitor" "SECID31"
2244.cindex "building Eximon"
168e428f
PH
2245A similar process is used for overriding things when building the Exim monitor,
2246where the files that are involved are
9b371988
PH
2247.display
2248&_OS/eximon.conf-Default_&
2249&_OS/eximon.conf-_&<&'ostype'&>
2250&_Local/eximon.conf_&
2251&_Local/eximon.conf-_&<&'ostype'&>
2252&_Local/eximon.conf-_&<&'archtype'&>
2253&_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2254.endd
2255.cindex "&_Local/eximon.conf_&"
168e428f 2256As with Exim itself, the final three files need not exist, and in this case the
9b371988
PH
2257&_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2258&_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
168e428f
PH
2259variables of the same name, preceded by EXIMON_. For example, setting
2260EXIMON_LOG_DEPTH in the environment overrides the value of
2261LOG_DEPTH at run time.
4f578862 2262.ecindex IIDbuex
168e428f
PH
2263
2264
f89d2485 2265.section "Installing Exim binaries and scripts" "SECID32"
9b371988
PH
2266.cindex "installing Exim"
2267.cindex "BIN_DIRECTORY"
2268The command &`make install`& runs the &(exim_install)& script with no
2269arguments. The script copies binaries and utility scripts into the directory
2270whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2271.cindex "setuid" "installing Exim with"
068aaea8
PH
2272The install script copies files only if they are newer than the files they are
2273going to replace. The Exim binary is required to be owned by root and have the
9b371988
PH
2274&'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2275install`& as root so that it can set up the Exim binary in this way. However, in
068aaea8
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2276some special situations (for example, if a host is doing no local deliveries)
2277it may be possible to run Exim without making the binary setuid root (see
9b371988 2278chapter &<<CHAPsecurity>>& for details).
168e428f 2279
9b371988 2280.cindex "CONFIGURE_FILE"
168e428f 2281Exim's run time configuration file is named by the CONFIGURE_FILE setting
9b371988
PH
2282in &_Local/Makefile_&. If this names a single file, and the file does not
2283exist, the default configuration file &_src/configure.default_& is copied there
168e428f
PH
2284by the installation script. If a run time configuration file already exists, it
2285is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2286alternative files, no default is installed.
2287
9b371988
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2288.cindex "system aliases file"
2289.cindex "&_/etc/aliases_&"
168e428f
PH
2290One change is made to the default configuration file when it is installed: the
2291default configuration contains a router that references a system aliases file.
2292The path to this file is set to the value specified by
9b371988 2293SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
168e428f
PH
2294If the system aliases file does not exist, the installation script creates it,
2295and outputs a comment to the user.
2296
2297The created file contains no aliases, but it does contain comments about the
2298aliases a site should normally have. Mail aliases have traditionally been
9b371988
PH
2299kept in &_/etc/aliases_&. However, some operating systems are now using
2300&_/etc/mail/aliases_&. You should check if yours is one of these, and change
168e428f
PH
2301Exim's configuration if necessary.
2302
2303The default configuration uses the local host's name as the only local domain,
9b371988
PH
2304and is set up to do local deliveries into the shared directory &_/var/mail_&,
2305running as the local user. System aliases and &_.forward_& files in users' home
168e428f
PH
2306directories are supported, but no NIS or NIS+ support is configured. Domains
2307other than the name of the local host are routed using the DNS, with delivery
2308over SMTP.
2309
168e428f
PH
2310It is possible to install Exim for special purposes (such as building a binary
2311distribution) in a private part of the file system. You can do this by a
2312command such as
9b371988
PH
2313.code
2314make DESTDIR=/some/directory/ install
2315.endd
168e428f
PH
2316This has the effect of pre-pending the specified directory to all the file
2317paths, except the name of the system aliases file that appears in the default
9b371988 2318configuration. (If a default alias file is created, its name &'is'& modified.)
168e428f
PH
2319For backwards compatibility, ROOT is used if DESTDIR is not set,
2320but this usage is deprecated.
2321
9b371988
PH
2322.cindex "installing Exim" "what is not installed"
2323Running &'make install'& does not copy the Exim 4 conversion script
40df1be3
TF
2324&'convert4r4'&. You will probably run this only once if you are
2325upgrading from Exim 3. None of the documentation files in the &_doc_&
168e428f 2326directory are copied, except for the info files when you have set
9b371988 2327INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
168e428f 2328
9b371988 2329For the utility programs, old versions are renamed by adding the suffix &_.O_&
168e428f
PH
2330to their names. The Exim binary itself, however, is handled differently. It is
2331installed under a name that includes the version number and the compile number,
2aee48d6 2332for example &_exim-&version()-1_&. The script then arranges for a symbolic link
9b371988
PH
2333called &_exim_& to point to the binary. If you are updating a previous version
2334of Exim, the script takes care to ensure that the name &_exim_& is never absent
168e428f
PH
2335from the directory (as seen by other processes).
2336
9b371988
PH
2337.cindex "installing Exim" "testing the script"
2338If you want to see what the &'make install'& will do before running it for
2339real, you can pass the &%-n%& option to the installation script by this
2340command:
2341.code
2342make INSTALL_ARG=-n install
2343.endd
168e428f
PH
2344The contents of the variable INSTALL_ARG are passed to the installation
2345script. You do not need to be root to run this test. Alternatively, you can run
2346the installation script directly, but this must be from within the build
2347directory. For example, from the top-level Exim directory you could use this
2348command:
9b371988
PH
2349.code
2350(cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2351.endd
2352.cindex "installing Exim" "install script options"
168e428f
PH
2353There are two other options that can be supplied to the installation script.
2354
9b371988
PH
2355.ilist
2356&%-no_chown%& bypasses the call to change the owner of the installed binary
168e428f 2357to root, and the call to make it a setuid binary.
9b371988
PH
2358.next
2359&%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
168e428f 2360installed binary.
9b371988 2361.endlist
168e428f
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2362
2363INSTALL_ARG can be used to pass these options to the script. For example:
9b371988
PH
2364.code
2365make INSTALL_ARG=-no_symlink install
2366.endd
168e428f
PH
2367The installation script can also be given arguments specifying which files are
2368to be copied. For example, to install just the Exim binary, and nothing else,
2369without creating the symbolic link, you could use:
9b371988
PH
2370.code
2371make INSTALL_ARG='-no_symlink exim' install
2372.endd
168e428f
PH
2373
2374
2375
9b371988
PH
2376.section "Installing info documentation" "SECTinsinfdoc"
2377.cindex "installing Exim" "&'info'& documentation"
2378Not all systems use the GNU &'info'& system for documentation, and for this
168e428f
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2379reason, the Texinfo source of Exim's documentation is not included in the main
2380distribution. Instead it is available separately from the ftp site (see section
9b371988 2381&<<SECTavail>>&).
168e428f 2382
9b371988
PH
2383If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2384source of the documentation is found in the source tree, running &`make
2385install`& automatically builds the info files and installs them.
168e428f
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2386
2387
2388
f89d2485 2389.section "Setting up the spool directory" "SECID33"
9b371988 2390.cindex "spool directory" "creating"
168e428f
PH
2391When it starts up, Exim tries to create its spool directory if it does not
2392exist. The Exim uid and gid are used for the owner and group of the spool
2393directory. Sub-directories are automatically created in the spool directory as
2394necessary.
2395
2396
2397
2398
f89d2485 2399.section "Testing" "SECID34"
9b371988 2400.cindex "testing" "installation"
168e428f
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2401Having installed Exim, you can check that the run time configuration file is
2402syntactically valid by running the following command, which assumes that the
2403Exim binary directory is within your PATH environment variable:
9b371988
PH
2404.code
2405exim -bV
2406.endd
168e428f
PH
2407If there are any errors in the configuration file, Exim outputs error messages.
2408Otherwise it outputs the version number and build date,
2409the DBM library that is being used, and information about which drivers and
2410other optional code modules are included in the binary.
2411Some simple routing tests can be done by using the address testing option. For
2412example,
9b371988
PH
2413.display
2414&`exim -bt`& <&'local username'&>
2415.endd
168e428f 2416should verify that it recognizes a local mailbox, and
9b371988
PH
2417.display
2418&`exim -bt`& <&'remote address'&>
2419.endd
168e428f
PH
2420a remote one. Then try getting it to deliver mail, both locally and remotely.
2421This can be done by passing messages directly to Exim, without going through a
2422user agent. For example:
9b371988 2423.code
068aaea8
PH
2424exim -v postmaster@your.domain.example
2425From: user@your.domain.example
2426To: postmaster@your.domain.example
2427Subject: Testing Exim
168e428f 2428
068aaea8
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2429This is a test message.
2430^D
9b371988
PH
2431.endd
2432The &%-v%& option causes Exim to output some verification of what it is doing.
168e428f 2433In this case you should see copies of three log lines, one for the message's
9b371988 2434arrival, one for its delivery, and one containing &"Completed"&.
168e428f 2435
9b371988
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2436.cindex "delivery" "problems with"
2437If you encounter problems, look at Exim's log files (&'mainlog'& and
2438&'paniclog'&) to see if there is any relevant information there. Another source
168e428f 2439of information is running Exim with debugging turned on, by specifying the
9b371988 2440&%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
168e428f 2441with debugging turned on by a command of the form
9b371988
PH
2442.display
2443&`exim -d -M`& <&'exim-message-id'&>
2444.endd
2445You must be root or an &"admin user"& in order to do this. The &%-d%& option
168e428f 2446produces rather a lot of output, but you can cut this down to specific areas.
9b371988
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2447For example, if you use &%-d-all+route%& only the debugging information
2448relevant to routing is included. (See the &%-d%& option in chapter
2449&<<CHAPcommandline>>& for more details.)
168e428f 2450
9b371988
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2451.cindex '&"sticky"& bit'
2452.cindex "lock files"
168e428f
PH
2453One specific problem that has shown up on some sites is the inability to do
2454local deliveries into a shared mailbox directory, because it does not have the
9b371988 2455&"sticky bit"& set on it. By default, Exim tries to create a lock file before
168e428f 2456writing to a mailbox file, and if it cannot create the lock file, the delivery
9b371988 2457is deferred. You can get round this either by setting the &"sticky bit"& on the
168e428f
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2458directory, or by setting a specific group for local deliveries and allowing
2459that group to create files in the directory (see the comments above the
9b371988 2460&(local_delivery)& transport in the default configuration file). Another
168e428f 2461approach is to configure Exim not to use lock files, but just to rely on
9b371988
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2462&[fcntl()]& locking instead. However, you should do this only if all user
2463agents also use &[fcntl()]& locking. For further discussion of locking issues,
2464see chapter &<<CHAPappendfile>>&.
168e428f
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2465
2466One thing that cannot be tested on a system that is already running an MTA is
2467the receipt of incoming SMTP mail on the standard SMTP port. However, the
9b371988
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2468&%-oX%& option can be used to run an Exim daemon that listens on some other
2469port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2470&'exim_checkaccess'& utility can be used to check out policy controls on
168e428f
PH
2471incoming SMTP mail.
2472
2473Testing a new version on a system that is already running Exim can most easily
2474be done by building a binary with a different CONFIGURE_FILE setting. From
2475within the run time configuration, all other file and directory names
2476that Exim uses can be altered, in order to keep it entirely clear of the
2477production version.
2478
2479
f89d2485 2480.section "Replacing another MTA with Exim" "SECID35"
9b371988 2481.cindex "replacing another MTA"
168e428f
PH
2482Building and installing Exim for the first time does not of itself put it in
2483general use. The name by which the system's MTA is called by mail user agents
9b371988
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2484is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2485operating system), and it is necessary to make this name point to the &'exim'&
168e428f 2486binary in order to get the user agents to pass messages to Exim. This is
9b371988
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2487normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2488or &_/usr/lib/sendmail_&
2489.cindex "symbolic link" "to &'exim'& binary"
2490a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
168e428f
PH
2491privilege and executable status from the old MTA. It is then necessary to stop
2492and restart the mailer daemon, if one is running.
2493
f89d2485 2494.cindex "FreeBSD, MTA indirection"
9b371988 2495.cindex "&_/etc/mail/mailer.conf_&"
168e428f
PH
2496Some operating systems have introduced alternative ways of switching MTAs. For
2497example, if you are running FreeBSD, you need to edit the file
9b371988 2498&_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
168e428f
PH
2499described. A typical example of the contents of this file for running Exim is
2500as follows:
9b371988
PH
2501.code
2502sendmail /usr/exim/bin/exim
2503send-mail /usr/exim/bin/exim
2504mailq /usr/exim/bin/exim -bp
2505newaliases /usr/bin/true
2506.endd
2507Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2508your Exim installation is &"live"&. Check it by sending a message from your
168e428f
PH
2509favourite user agent.
2510
2511You should consider what to tell your users about the change of MTA. Exim may
2512have different capabilities to what was previously running, and there are
2513various operational differences such as the text of messages produced by
2514command line options and in bounce messages. If you allow your users to make
2515use of Exim's filtering capabilities, you should make the document entitled
9b371988 2516&'Exim's interface to mail filtering'& available to them.
168e428f
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2517
2518
2519
f89d2485 2520.section "Upgrading Exim" "SECID36"
9b371988 2521.cindex "upgrading Exim"
168e428f
PH
2522If you are already running Exim on your host, building and installing a new
2523version automatically makes it available to MUAs, or any other programs that
2524call the MTA directly. However, if you are running an Exim daemon, you do need
9b371988
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2525to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2526new binary. You do not need to stop processing mail in order to install a new
068aaea8
PH
2527version of Exim. The install script does not modify an existing runtime
2528configuration file.
2529
168e428f
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2530
2531
2532
f89d2485 2533.section "Stopping the Exim daemon on Solaris" "SECID37"
9b371988 2534.cindex "Solaris" "stopping Exim on"
168e428f 2535The standard command for stopping the mailer daemon on Solaris is
9b371988
PH
2536.code
2537/etc/init.d/sendmail stop
2538.endd
2539If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2540fails to stop Exim because it uses the command &'ps -e'& and greps the output
2541for the text &"sendmail"&; this is not present because the actual program name
2542(that is, &"exim"&) is given by the &'ps'& command with these options. A
2543solution is to replace the line that finds the process id with something like
2544.code
2545pid=`cat /var/spool/exim/exim-daemon.pid`
2546.endd
168e428f
PH
2547to obtain the daemon's pid directly from the file that Exim saves it in.
2548
9b371988 2549Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
168e428f
PH
2550still be received from local processes, and if automatic delivery is configured
2551(the normal case), deliveries will still occur.
2552
2553
2554
2555
9b371988
PH
2556. ////////////////////////////////////////////////////////////////////////////
2557. ////////////////////////////////////////////////////////////////////////////
168e428f 2558
9b371988 2559.chapter "The Exim command line" "CHAPcommandline"
4f578862
PH
2560.scindex IIDclo1 "command line" "options"
2561.scindex IIDclo2 "options" "command line"
168e428f
PH
2562Exim's command line takes the standard Unix form of a sequence of options,
2563each starting with a hyphen character, followed by a number of arguments. The
2564options are compatible with the main options of Sendmail, and there are also
2565some additional options, some of which are compatible with Smail 3. Certain
2566combinations of options do not make sense, and provoke an error if used.
2567The form of the arguments depends on which options are set.
2568
2569
f89d2485 2570.section "Setting options by program name" "SECID38"
9b371988
PH
2571.cindex "&'mailq'&"
2572If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
168e428f 2573were present before any other options.
9b371988 2574The &%-bp%& option requests a listing of the contents of the mail queue on the
168e428f
PH
2575standard output.
2576This feature is for compatibility with some systems that contain a command of
2577that name in one of the standard libraries, symbolically linked to
9b371988
PH
2578&_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2579
2580.cindex "&'rsmtp'&"
2581If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2582were present before any other options, for compatibility with Smail. The
2583&%-bS%& option is used for reading in a number of messages in batched SMTP
2584format.
2585
2586.cindex "&'rmail'&"
2587If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2588&%-oee%& options were present before any other options, for compatibility with
2589Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2590
2591.cindex "&'runq'&"
2592.cindex "queue runner"
2593If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2594were present before any other options, for compatibility with Smail. The &%-q%&
168e428f
PH
2595option causes a single queue runner process to be started.
2596
9b371988
PH
2597.cindex "&'newaliases'&"
2598.cindex "alias file" "building"
2599.cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2600If Exim is called under the name &'newaliases'& it behaves as if the option
2601&%-bi%& were present before any other options, for compatibility with Sendmail.
168e428f
PH
2602This option is used for rebuilding Sendmail's alias file. Exim does not have
2603the concept of a single alias file, but can be configured to run a given
9b371988 2604command if called with the &%-bi%& option.
168e428f
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2605
2606
9b371988
PH
2607.section "Trusted and admin users" "SECTtrustedadmin"
2608Some Exim options are available only to &'trusted users'& and others are
2609available only to &'admin users'&. In the description below, the phrases &"Exim
2610user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2611EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2612&%exim_group%& options. These do not necessarily have to use the name &"exim"&.
168e428f 2613
9b371988 2614.ilist
f89d2485 2615.cindex "trusted users" "definition of"
9b371988 2616.cindex "user" "trusted definition of"
168e428f 2617The trusted users are root, the Exim user, any user listed in the
9b371988
PH
2618&%trusted_users%& configuration option, and any user whose current group or any
2619supplementary group is one of those listed in the &%trusted_groups%&
168e428f 2620configuration option. Note that the Exim group is not automatically trusted.
9b371988
PH
2621
2622.cindex '&"From"& line'
2623.cindex "envelope sender"
2624Trusted users are always permitted to use the &%-f%& option or a leading
2625&"From&~"& line to specify the envelope sender of a message that is passed to
2626Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2627See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2628users to set envelope senders.
2629
2630.cindex "&'From:'& header line"
2631.cindex "&'Sender:'& header line"
2632For a trusted user, there is never any check on the contents of the &'From:'&
2633header line, and a &'Sender:'& line is never added. Furthermore, any existing
2634&'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2635
168e428f
PH
2636Trusted users may also specify a host name, host address, interface address,
2637protocol name, ident value, and authentication data when submitting a message
2638locally. Thus, they are able to insert messages into Exim's queue locally that
2639have the characteristics of messages received from a remote host. Untrusted
9b371988 2640users may in some circumstances use &%-f%&, but can never set the other values
168e428f 2641that are available to trusted users.
9b371988
PH
2642.next
2643.cindex "user" "admin definition of"
2644.cindex "admin user" "definition of"
168e428f 2645The admin users are root, the Exim user, and any user that is a member of the
9b371988 2646Exim group or of any group listed in the &%admin_groups%& configuration option.
168e428f 2647The current group does not have to be one of these groups.
9b371988 2648
168e428f
PH
2649Admin users are permitted to list the queue, and to carry out certain
2650operations on messages, for example, to force delivery failures. It is also
2651necessary to be an admin user in order to see the full information provided by
2652the Exim monitor, and full debugging output.
9b371988
PH
2653
2654By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2655Exim to attempt delivery of messages on its queue is restricted to admin users.
2656However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2657option false (that is, specifying &%no_prod_requires_admin%&).
2658
2659Similarly, the use of the &%-bp%& option to list all the messages in the queue
2660is restricted to admin users unless &%queue_list_requires_admin%& is set
168e428f 2661false.
9b371988 2662.endlist
168e428f
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2663
2664
9b371988 2665&*Warning*&: If you configure your system so that admin users are able to
168e428f
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2666edit Exim's configuration file, you are giving those users an easy way of
2667getting root. There is further discussion of this issue at the start of chapter
9b371988 2668&<<CHAPconf>>&.
168e428f
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2669
2670
2671
2672
f89d2485 2673.section "Command line options" "SECID39"
db9452a9
PH
2674Exim's command line options are described in alphabetical order below. If none
2675of the options that specifies a specific action (such as starting the daemon or
2676a queue runner, or testing an address, or receiving a message in a specific
2677format, or listing the queue) are present, and there is at least one argument
2678on the command line, &%-bm%& (accept a local message on the standard input,
2679with the arguments specifying the recipients) is assumed. Otherwise, Exim
2680outputs a brief message about itself and exits.
168e428f 2681
9b371988
PH
2682. ////////////////////////////////////////////////////////////////////////////
2683. Insert a stylized XML comment here, to identify the start of the command line
2684. options. This is for the benefit of the Perl script that automatically
2685. creates a man page for the options.
2686. ////////////////////////////////////////////////////////////////////////////
168e428f 2687
9b371988 2688.literal xml
168e428f 2689<!-- === Start of command line options === -->
9b371988 2690.literal off
168e428f
PH
2691
2692
9b371988
PH
2693.vlist
2694.vitem &%--%&
2695.oindex "--"
2696.cindex "options" "command line; terminating"
168e428f
PH
2697This is a pseudo-option whose only purpose is to terminate the options and
2698therefore to cause subsequent command line items to be treated as arguments
2699rather than options, even if they begin with hyphens.
2700
9b371988
PH
2701.vitem &%--help%&
2702.oindex "&%--help%&"
168e428f
PH
2703This option causes Exim to output a few sentences stating what it is.
2704The same output is generated if the Exim binary is called with no options and
2705no arguments.
2706
4b2241d2
PP
2707.vitem &%--version%&
2708.oindex "&%--version%&"
2709This option is an alias for &%-bV%& and causes version information to be
2710displayed.
2711
a3fb9793
PP
2712.new
2713.vitem &%-Ac%& &&&
2714 &%-Am%&
2715.oindex "&%-Ac%&"
2716.oindex "&%-Am%&"
2717These options are used by Sendmail for selecting configuration files and are
2718ignored by Exim.
2719.wen
2720
9b371988
PH
2721.vitem &%-B%&<&'type'&>
2722.oindex "&%-B%&"
2723.cindex "8-bit characters"
2724.cindex "Sendmail compatibility" "8-bit characters"
168e428f
PH
2725This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2726clean; it ignores this option.
2727
9b371988
PH
2728.vitem &%-bd%&
2729.oindex "&%-bd%&"
2730.cindex "daemon"
f89d2485 2731.cindex "SMTP" "listener"
9b371988 2732.cindex "queue runner"
168e428f 2733This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
9b371988
PH
2734the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2735that the daemon should also initiate periodic queue runs.
2736
2737The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2738(debugging) or &%-v%& (verifying) options are set, the daemon does not
168e428f
PH
2739disconnect from the controlling terminal. When running this way, it can be
2740stopped by pressing ctrl-C.
9b371988 2741
168e428f
PH
2742By default, Exim listens for incoming connections to the standard SMTP port on
2743all the host's running interfaces. However, it is possible to listen on other
2744ports, on multiple ports, and only on specific interfaces. Chapter
9b371988
PH
2745&<<CHAPinterfaces>>& contains a description of the options that control this.
2746
168e428f 2747When a listening daemon
9b371988
PH
2748.cindex "daemon" "process id (pid)"
2749.cindex "pid (process id)" "of daemon"
2750is started without the use of &%-oX%& (that is, without overriding the normal
2751configuration), it writes its process id to a file called &_exim-daemon.pid_&
2752in Exim's spool directory. This location can be overridden by setting
2753PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
168e428f 2754running as root.
9b371988
PH
2755
2756When &%-oX%& is used on the command line to start a listening daemon, the
2757process id is not written to the normal pid file path. However, &%-oP%& can be
168e428f 2758used to specify a path on the command line if a pid file is required.
9b371988 2759
168e428f 2760The SIGHUP signal
9b371988 2761.cindex "SIGHUP"
3cb1b51e
PH
2762.cindex "daemon" "restarting"
2763can be used to cause the daemon to re-execute itself. This should be done
2764whenever Exim's configuration file, or any file that is incorporated into it by
2765means of the &%.include%& facility, is changed, and also whenever a new version
2766of Exim is installed. It is not necessary to do this when other files that are
9b371988
PH
2767referenced from the configuration (for example, alias files) are changed,
2768because these are reread each time they are used.
2769
2770.vitem &%-bdf%&
2771.oindex "&%-bdf%&"
2772This option has the same effect as &%-bd%& except that it never disconnects
2773from the controlling terminal, even when no debugging is specified.
2774
2775.vitem &%-be%&
2776.oindex "&%-be%&"
2777.cindex "testing" "string expansion"
2778.cindex "expansion" "testing"
168e428f
PH
2779Run Exim in expansion testing mode. Exim discards its root privilege, to
2780prevent ordinary users from using this mode to read otherwise inaccessible
2781files. If no arguments are given, Exim runs interactively, prompting for lines
4f578862 2782of data. Otherwise, it processes each argument in turn.
9b371988
PH
2783
2784If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2785to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2786used without command line arguments. If successful, it uses the &[readline()]&
168e428f
PH
2787function, which provides extensive line-editing facilities, for reading the
2788test data. A line history is supported.
9b371988 2789
168e428f 2790Long expansion expressions can be split over several lines by using backslash
068aaea8 2791continuations. As in Exim's run time configuration, white space at the start of
168e428f
PH
2792continuation lines is ignored. Each argument or data line is passed through the
2793string expansion mechanism, and the result is output. Variable values from the
9b371988 2794configuration file (for example, &$qualify_domain$&) are available, but no
3cb1b51e 2795message-specific values (such as &$sender_domain$&) are set, because no message
f89d2485 2796is being processed (but see &%-bem%& and &%-Mset%&).
168e428f 2797
9b371988
PH
2798&*Note*&: If you use this mechanism to test lookups, and you change the data
2799files or databases you are using, you must exit and restart Exim before trying
2800the same lookup again. Otherwise, because each Exim process caches the results
2801of lookups, you will just get the same result as before.
9b371988 2802
3cb1b51e
PH
2803.vitem &%-bem%&&~<&'filename'&>
2804.oindex "&%-bem%&"
2805.cindex "testing" "string expansion"
2806.cindex "expansion" "testing"
2807This option operates like &%-be%& except that it must be followed by the name
2808of a file. For example:
2809.code
2810exim -bem /tmp/testmessage
2811.endd
2812The file is read as a message (as if receiving a locally-submitted non-SMTP
2813message) before any of the test expansions are done. Thus, message-specific
2814variables such as &$message_size$& and &$header_from:$& are available. However,
2815no &'Received:'& header is added to the message. If the &%-t%& option is set,
2816recipients are read from the headers in the normal way, and are shown in the
2817&$recipients$& variable. Note that recipients cannot be given on the command
2818line, because further arguments are taken as strings to expand (just like
2819&%-be%&).
3cb1b51e 2820
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2821.vitem &%-bF%&&~<&'filename'&>
2822.oindex "&%-bF%&"
2823.cindex "system filter" "testing"
2824.cindex "testing" "system filter"
2825This option is the same as &%-bf%& except that it assumes that the filter being
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2826tested is a system filter. The additional commands that are available only in
2827system filters are recognized.
2828
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2829.vitem &%-bf%&&~<&'filename'&>
2830.oindex "&%-bf%&"
2831.cindex "filter" "testing"
2832.cindex "testing" "filter file"
2833.cindex "forward file" "testing"
2834.cindex "testing" "forward file"
2835.cindex "Sieve filter" "testing"
168e428f
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2836This option runs Exim in user filter testing mode; the file is the filter file
2837to be tested, and a test message must be supplied on the standard input. If
2838there are no message-dependent tests in the filter, an empty file can be
2839supplied.
168e428f 2840
9b371988
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2841If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2842can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2843filter and a user filter in the same run. For example:
2844.code
2845exim -bF /system/filter -bf /user/filter </test/message
2846.endd
168e428f
PH
2847This is helpful when the system filter adds header lines or sets filter
2848variables that are used by the user filter.
168e428f 2849
9b371988
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2850If the test filter file does not begin with one of the special lines
2851.code
2852# Exim filter
2853# Sieve filter
2854.endd
2855it is taken to be a normal &_.forward_& file, and is tested for validity under
2856that interpretation. See sections &<<SECTitenonfilred>>& to
2857&<<SECTspecitredli>>& for a description of the possible contents of non-filter
2858redirection lists.
2859
2860The result of an Exim command that uses &%-bf%&, provided no errors are
168e428f
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2861detected, is a list of the actions that Exim would try to take if presented
2862with the message for real. More details of filter testing are given in the
9b371988
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2863separate document entitled &'Exim's interfaces to mail filtering'&.
2864
168e428f 2865When testing a filter file,
9b371988
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2866.cindex "&""From""& line"
2867.cindex "envelope sender"
f89d2485 2868.oindex "&%-f%&" "for filter testing"
9b371988
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2869the envelope sender can be set by the &%-f%& option,
2870or by a &"From&~"& line at the start of the test message. Various parameters
2871that would normally be taken from the envelope recipient address of the message
2872can be set by means of additional command line options (see the next four
2873options).
2874
2875.vitem &%-bfd%&&~<&'domain'&>
2876.oindex "&%-bfd%&"
f89d2485 2877.vindex "&$qualify_domain$&"
168e428f 2878This sets the domain of the recipient address when a filter file is being
9b371988
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2879tested by means of the &%-bf%& option. The default is the value of
2880&$qualify_domain$&.
168e428f 2881
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2882.vitem &%-bfl%&&~<&'local&~part'&>
2883.oindex "&%-bfl%&"
168e428f 2884This sets the local part of the recipient address when a filter file is being
9b371988 2885tested by means of the &%-bf%& option. The default is the username of the
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2886process that calls Exim. A local part should be specified with any prefix or
2887suffix stripped, because that is how it appears to the filter when a message is
2888actually being delivered.
2889
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2890.vitem &%-bfp%&&~<&'prefix'&>
2891.oindex "&%-bfp%&"
168e428f 2892This sets the prefix of the local part of the recipient address when a filter
9b371988 2893file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
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2894prefix.
2895
9b371988
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2896.vitem &%-bfs%&&~<&'suffix'&>
2897.oindex "&%-bfs%&"
168e428f 2898This sets the suffix of the local part of the recipient address when a filter
9b371988 2899file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
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2900suffix.
2901
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2902.vitem &%-bh%&&~<&'IP&~address'&>
2903.oindex "&%-bh%&"
2904.cindex "testing" "incoming SMTP"
2905.cindex "SMTP" "testing incoming"
2906.cindex "testing" "relay control"
2907.cindex "relaying" "testing configuration"
2908.cindex "policy control" "testing"
2909.cindex "debugging" "&%-bh%& option"
168e428f
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2910This option runs a fake SMTP session as if from the given IP address, using the
2911standard input and output. The IP address may include a port number at the end,
2912after a full stop. For example:
9b371988
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2913.code
2914exim -bh 10.9.8.7.1234
2915exim -bh fe80::a00:20ff:fe86:a061.5678
2916.endd
168e428f 2917When an IPv6 address is given, it is converted into canonical form. In the case
9b371988
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2918of the second example above, the value of &$sender_host_address$& after
2919conversion to the canonical form is
2920&`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2921
168e428f 2922Comments as to what is going on are written to the standard error file. These
9b371988 2923include lines beginning with &"LOG"& for anything that would have been logged.
168e428f
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2924This facility is provided for testing configuration options for incoming
2925messages, to make sure they implement the required policy. For example, you can
9b371988
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2926test your relay controls using &%-bh%&.
2927
2928&*Warning 1*&:
2929.cindex "RFC 1413"
db9452a9
PH
2930You can test features of the configuration that rely on ident (RFC 1413)
2931information by using the &%-oMt%& option. However, Exim cannot actually perform
2932an ident callout when testing using &%-bh%& because there is no incoming SMTP
2933connection.
9b371988
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2934
2935&*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2936are also skipped when testing using &%-bh%&. If you want these callouts to
2937occur, use &%-bhc%& instead.
2938
168e428f
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2939Messages supplied during the testing session are discarded, and nothing is
2940written to any of the real log files. There may be pauses when DNS (and other)
9b371988 2941lookups are taking place, and of course these may time out. The &%-oMi%& option
db9452a9
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2942can be used to specify a specific IP interface and port if this is important,
2943and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2944session were authenticated.
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2945
2946The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
168e428f 2947output just states whether a given recipient address from a given host is
9b371988 2948acceptable or not. See section &<<SECTcheckaccess>>&.
168e428f 2949
3cb1b51e 2950Features such as authentication and encryption, where the client input is not
f89d2485
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2951plain text, cannot easily be tested with &%-bh%&. Instead, you should use a
2952specialized SMTP test program such as
3cb1b51e 2953&url(http://jetmore.org/john/code/#swaks,swaks).
3cb1b51e 2954
9b371988
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2955.vitem &%-bhc%&&~<&'IP&~address'&>
2956.oindex "&%-bhc%&"
2957This option operates in the same way as &%-bh%&, except that address
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2958verification callouts are performed if required. This includes consulting and
2959updating the callout cache database.
2960
9b371988
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2961.vitem &%-bi%&
2962.oindex "&%-bi%&"
2963.cindex "alias file" "building"
2964.cindex "building alias file"
2965.cindex "Sendmail compatibility" "&%-bi%& option"
2966Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
168e428f 2967Exim does not have the concept of a single alias file, and so it cannot mimic
9b371988 2968this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
168e428f
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2969tend to appear in various scripts such as NIS make files, so the option must be
2970recognized.
9b371988
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2971
2972If &%-bi%& is encountered, the command specified by the &%bi_command%&
168e428f 2973configuration option is run, under the uid and gid of the caller of Exim. If
9b371988
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2974the &%-oA%& option is used, its value is passed to the command as an argument.
2975The command set by &%bi_command%& may not contain arguments. The command can
2976use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2977if this is required. If the &%bi_command%& option is not set, calling Exim with
2978&%-bi%& is a no-op.
2979
12f69989 2980.new
36a3ae5f 2981. // Keep :help first, then the rest in alphabetical order
98a90c36
PP
2982.vitem &%-bI:help%&
2983.oindex "&%-bI:help%&"
2984.cindex "querying exim information"
2985We shall provide various options starting &`-bI:`& for querying Exim for
2986information. The output of many of these will be intended for machine
2987consumption. This one is not. The &%-bI:help%& option asks Exim for a
2988synopsis of supported options beginning &`-bI:`&. Use of any of these
2989options shall cause Exim to exit after producing the requested output.
2990
36a3ae5f
PP
2991.vitem &%-bI:dscp%&
2992.oindex "&%-bI:dscp%&"
2993.cindex "DSCP" "values"
2994This option causes Exim to emit an alphabetically sorted list of all
2995recognised DSCP names.
2996
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PP
2997.vitem &%-bI:sieve%&
2998.oindex "&%-bI:sieve%&"
2999.cindex "Sieve filter" "capabilities"
3000This option causes Exim to emit an alphabetically sorted list of all supported
3001Sieve protocol extensions on stdout, one per line. This is anticipated to be
3002useful for ManageSieve (RFC 5804) implementations, in providing that protocol's
3003&`SIEVE`& capability response line. As the precise list may depend upon
3004compile-time build options, which this option will adapt to, this is the only
3005way to guarantee a correct response.
12f69989 3006.wen
98a90c36 3007
9b371988
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3008.vitem &%-bm%&
3009.oindex "&%-bm%&"
3010.cindex "local message reception"
168e428f 3011This option runs an Exim receiving process that accepts an incoming,
a543079f 3012locally-generated message on the standard input. The recipients are given as the
9b371988 3013command arguments (except when &%-t%& is also present &-- see below). Each
168e428f
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3014argument can be a comma-separated list of RFC 2822 addresses. This is the
3015default option for selecting the overall action of an Exim call; it is assumed
3016if no other conflicting option is present.
9b371988 3017
168e428f 3018If any addresses in the message are unqualified (have no domain), they are
9b371988
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3019qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
3020options, as appropriate. The &%-bnq%& option (see below) provides a way of
168e428f 3021suppressing this for special cases.
9b371988 3022
168e428f 3023Policy checks on the contents of local messages can be enforced by means of
9b371988
PH
3024the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
3025
3026.cindex "return code" "for &%-bm%&"
3027The return code is zero if the message is successfully accepted. Otherwise, the
3028action is controlled by the &%-oe%&&'x'& option setting &-- see below.
3029
168e428f 3030The format
9b371988
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3031.cindex "message" "format"
3032.cindex "format" "message"
3033.cindex "&""From""& line"
3034.cindex "UUCP" "&""From""& line"
3035.cindex "Sendmail compatibility" "&""From""& line"
168e428f
PH
3036of the message must be as defined in RFC 2822, except that, for
3037compatibility with Sendmail and Smail, a line in one of the forms
9b371988
PH
3038.code
3039From sender Fri Jan 5 12:55 GMT 1997
3040From sender Fri, 5 Jan 97 12:55:01
3041.endd
168e428f
PH
3042(with the weekday optional, and possibly with additional text after the date)
3043is permitted to appear at the start of the message. There appears to be no
3044authoritative specification of the format of this line. Exim recognizes it by
9b371988 3045matching against the regular expression defined by the &%uucp_from_pattern%&
168e428f 3046option, which can be changed if necessary.
9b371988 3047
f89d2485
PH
3048.oindex "&%-f%&" "overriding &""From""& line"
3049The specified sender is treated as if it were given as the argument to the
9b371988 3050&%-f%& option, but if a &%-f%& option is also present, its argument is used in
168e428f
PH
3051preference to the address taken from the message. The caller of Exim must be a
3052trusted user for the sender of a message to be set in this way.
3053
5b257915
PP
3054.vitem &%-bmalware%&&~<&'filename'&>
3055.oindex "&%-bmalware%&"
3056.cindex "testing", "malware"
3057.cindex "malware scan test"
3058This debugging option causes Exim to scan the given file,
3059using the malware scanning framework. The option of &%av_scanner%& influences
3060this option, so if &%av_scanner%&'s value is dependent upon an expansion then
3061the expansion should have defaults which apply to this invocation. ACLs are
3062not invoked, so if &%av_scanner%& references an ACL variable then that variable
3063will never be populated and &%-bmalware%& will fail.
3064
3065Exim will have changed working directory before resolving the filename, so
3066using fully qualified pathnames is advisable. Exim will be running as the Exim
3067user when it tries to open th