Insert version number and date into documentation at build time. Bug 1318.
[exim.git] / doc / doc-docbook / spec.xfpt
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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.
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45. /////////////////////////////////////////////////////////////////////////////
46
2341d632 47.set previousversion "4.80"
2aee48d6 48.include ./local_params
f89d2485 49
33393583 50.set ACL "access control lists (ACLs)"
f89d2485 51.set I "&nbsp;&nbsp;&nbsp;&nbsp;"
33393583 52
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53
54. /////////////////////////////////////////////////////////////////////////////
55. Additional xfpt markup used by this document, over and above the default
56. provided in the xfpt library.
57. /////////////////////////////////////////////////////////////////////////////
58
59. --- Override the &$ flag to automatically insert a $ with the variable name
60
61.flag &$ $& "<varname>$" "</varname>"
62
63. --- Short flags for daggers in option headings. They will always be inside
64. --- an italic string, but we want the daggers to be roman.
65
66.flag &!! "</emphasis>&dagger;<emphasis>"
67.flag &!? "</emphasis>&Dagger;<emphasis>"
68
69. --- A macro for an Exim option definition heading, generating a one-line
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70. --- table with four columns. For cases when the option name is given with
71. --- a space, so that it can be split, a fifth argument is used for the
72. --- index entry.
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73
74.macro option
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75.arg 5
76.oindex "&%$5%&"
77.endarg
78.arg -5
3cb1b51e 79.oindex "&%$1%&"
0a4e3112 80.endarg
f89d2485 81.itable all 0 0 4 8* left 6* center 6* center 6* right
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82.row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&"
83.endtable
84.endmacro
85
86. --- A macro for the common 2-column tables. The width of the first column
87. --- is suitable for the many tables at the start of the main options chapter;
88. --- the small number of other 2-column tables override it.
89
db9452a9 90.macro table2 196pt 254pt
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91.itable none 0 0 2 $1 left $2 left
92.endmacro
93
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94. --- A macro that generates .row, but puts &I; at the start of the first
95. --- argument, thus indenting it. Assume a minimum of two arguments, and
96. --- allow up to four arguments, which is as many as we'll ever need.
97
98.macro irow
99.arg 4
100.row "&I;$1" "$2" "$3" "$4"
101.endarg
102.arg -4
103.arg 3
104.row "&I;$1" "$2" "$3"
105.endarg
106.arg -3
107.row "&I;$1" "$2"
108.endarg
109.endarg
110.endmacro
111
112. --- Macros for option, variable, and concept index entries. For a "range"
113. --- style of entry, use .scindex for the start and .ecindex for the end. The
114. --- first argument of .scindex and the only argument of .ecindex must be the
115. --- ID that ties them together.
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116
117.macro cindex
118&<indexterm role="concept">&
119&<primary>&$1&</primary>&
120.arg 2
121&<secondary>&$2&</secondary>&
122.endarg
123&</indexterm>&
124.endmacro
125
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126.macro scindex
127&<indexterm role="concept" id="$1" class="startofrange">&
128&<primary>&$2&</primary>&
129.arg 3
130&<secondary>&$3&</secondary>&
131.endarg
132&</indexterm>&
133.endmacro
134
135.macro ecindex
136&<indexterm role="concept" startref="$1" class="endofrange"/>&
137.endmacro
138
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139.macro oindex
140&<indexterm role="option">&
141&<primary>&$1&</primary>&
142.arg 2
143&<secondary>&$2&</secondary>&
144.endarg
145&</indexterm>&
146.endmacro
147
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148.macro vindex
149&<indexterm role="variable">&
150&<primary>&$1&</primary>&
151.arg 2
152&<secondary>&$2&</secondary>&
153.endarg
154&</indexterm>&
155.endmacro
156
9b371988 157.macro index
f89d2485 158.echo "** Don't use .index; use .cindex or .oindex or .vindex"
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159.endmacro
160. ////////////////////////////////////////////////////////////////////////////
161
162
163. ////////////////////////////////////////////////////////////////////////////
164. The <bookinfo> element is removed from the XML before processing for Ascii
165. output formats.
166. ////////////////////////////////////////////////////////////////////////////
167
168.literal xml
169<bookinfo>
170<title>Specification of the Exim Mail Transfer Agent</title>
171<titleabbrev>The Exim MTA</titleabbrev>
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172<date>
173.fulldate
174</date>
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175<author><firstname>Exim</firstname><surname>Maintainers</surname></author>
176<authorinitials>EM</authorinitials>
9b371988 177<revhistory><revision>
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178 <revnumber>
179.version
180 </revnumber>
181 <date>
182.fulldate
183 </date>
7b4c60eb 184 <authorinitials>EM</authorinitials>
9b371988 185</revision></revhistory>
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186<copyright><year>
187.year
188 </year><holder>University of Cambridge</holder></copyright>
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189</bookinfo>
190.literal off
191
192
193. /////////////////////////////////////////////////////////////////////////////
194. This chunk of literal XML implements index entries of the form "x, see y" and
195. "x, see also y". However, the DocBook DTD doesn't allow <indexterm> entries
196. at the top level, so we have to put the .chapter directive first.
197. /////////////////////////////////////////////////////////////////////////////
198
f89d2485 199.chapter "Introduction" "CHID1"
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200.literal xml
201
f89d2485 202<indexterm role="variable">
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203 <primary>$1, $2, etc.</primary>
204 <see><emphasis>numerical variables</emphasis></see>
205</indexterm>
206<indexterm role="concept">
207 <primary>address</primary>
208 <secondary>rewriting</secondary>
209 <see><emphasis>rewriting</emphasis></see>
210</indexterm>
211<indexterm role="concept">
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212 <primary>Bounce Address Tag Validation</primary>
213 <see><emphasis>BATV</emphasis></see>
214</indexterm>
215<indexterm role="concept">
216 <primary>Client SMTP Authorization</primary>
217 <see><emphasis>CSA</emphasis></see>
218</indexterm>
219<indexterm role="concept">
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220 <primary>CR character</primary>
221 <see><emphasis>carriage return</emphasis></see>
222</indexterm>
223<indexterm role="concept">
224 <primary>CRL</primary>
225 <see><emphasis>certificate revocation list</emphasis></see>
226</indexterm>
227<indexterm role="concept">
228 <primary>delivery</primary>
229 <secondary>failure report</secondary>
230 <see><emphasis>bounce message</emphasis></see>
231</indexterm>
232<indexterm role="concept">
233 <primary>dialup</primary>
234 <see><emphasis>intermittently connected hosts</emphasis></see>
235</indexterm>
236<indexterm role="concept">
237 <primary>exiscan</primary>
238 <see><emphasis>content scanning</emphasis></see>
239</indexterm>
240<indexterm role="concept">
241 <primary>failover</primary>
242 <see><emphasis>fallback</emphasis></see>
243</indexterm>
244<indexterm role="concept">
245 <primary>fallover</primary>
246 <see><emphasis>fallback</emphasis></see>
247</indexterm>
248<indexterm role="concept">
249 <primary>filter</primary>
250 <secondary>Sieve</secondary>
251 <see><emphasis>Sieve filter</emphasis></see>
252</indexterm>
253<indexterm role="concept">
254 <primary>ident</primary>
255 <see><emphasis>RFC 1413</emphasis></see>
256</indexterm>
257<indexterm role="concept">
258 <primary>LF character</primary>
259 <see><emphasis>linefeed</emphasis></see>
260</indexterm>
261<indexterm role="concept">
262 <primary>maximum</primary>
595028e4 263 <seealso><emphasis>limit</emphasis></seealso>
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264</indexterm>
265<indexterm role="concept">
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266 <primary>monitor</primary>
267 <see><emphasis>Exim monitor</emphasis></see>
268</indexterm>
269<indexterm role="concept">
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270 <primary>no_<emphasis>xxx</emphasis></primary>
271 <see>entry for xxx</see>
272</indexterm>
273<indexterm role="concept">
274 <primary>NUL</primary>
275 <see><emphasis>binary zero</emphasis></see>
276</indexterm>
277<indexterm role="concept">
278 <primary>passwd file</primary>
279 <see><emphasis>/etc/passwd</emphasis></see>
280</indexterm>
281<indexterm role="concept">
282 <primary>process id</primary>
283 <see><emphasis>pid</emphasis></see>
284</indexterm>
285<indexterm role="concept">
286 <primary>RBL</primary>
287 <see><emphasis>DNS list</emphasis></see>
288</indexterm>
289<indexterm role="concept">
290 <primary>redirection</primary>
291 <see><emphasis>address redirection</emphasis></see>
292</indexterm>
293<indexterm role="concept">
294 <primary>return path</primary>
295 <seealso><emphasis>envelope sender</emphasis></seealso>
296</indexterm>
297<indexterm role="concept">
298 <primary>scanning</primary>
299 <see><emphasis>content scanning</emphasis></see>
300</indexterm>
301<indexterm role="concept">
302 <primary>SSL</primary>
303 <see><emphasis>TLS</emphasis></see>
304</indexterm>
305<indexterm role="concept">
306 <primary>string</primary>
307 <secondary>expansion</secondary>
308 <see><emphasis>expansion</emphasis></see>
309</indexterm>
310<indexterm role="concept">
311 <primary>top bit</primary>
312 <see><emphasis>8-bit characters</emphasis></see>
313</indexterm>
314<indexterm role="concept">
315 <primary>variables</primary>
316 <see><emphasis>expansion, variables</emphasis></see>
317</indexterm>
318<indexterm role="concept">
319 <primary>zero, binary</primary>
320 <see><emphasis>binary zero</emphasis></see>
321</indexterm>
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322
323.literal off
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324
325
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326. /////////////////////////////////////////////////////////////////////////////
327. This is the real start of the first chapter. See the comment above as to why
328. we can't have the .chapter line here.
329. chapter "Introduction"
330. /////////////////////////////////////////////////////////////////////////////
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331
332Exim is a mail transfer agent (MTA) for hosts that are running Unix or
333Unix-like operating systems. It was designed on the assumption that it would be
334run on hosts that are permanently connected to the Internet. However, it can be
335used on intermittently connected hosts with suitable configuration adjustments.
336
337Configuration files currently exist for the following operating systems: AIX,
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338BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, Dragonfly, FreeBSD, GNU/Hurd,
339GNU/Linux, HI-OSF (Hitachi), HI-UX, HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD,
340OpenUNIX, QNX, SCO, SCO SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4,
341Tru64-Unix (formerly Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware.
342Some of these operating systems are no longer current and cannot easily be
343tested, so the configuration files may no longer work in practice.
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344
345There are also configuration files for compiling Exim in the Cygwin environment
346that can be installed on systems running Windows. However, this document does
347not contain any information about running Exim in the Cygwin environment.
348
349The terms and conditions for the use and distribution of Exim are contained in
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350the file &_NOTICE_&. Exim is distributed under the terms of the GNU General
351Public Licence, a copy of which may be found in the file &_LICENCE_&.
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352
353The use, supply or promotion of Exim for the purpose of sending bulk,
354unsolicited electronic mail is incompatible with the basic aims of the program,
355which revolve around the free provision of a service that enhances the quality
356of personal communications. The author of Exim regards indiscriminate
357mass-mailing as an antisocial, irresponsible abuse of the Internet.
358
359Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
360experience of running and working on the Smail 3 code, I could never have
361contemplated starting to write a new MTA. Many of the ideas and user interfaces
362were originally taken from Smail 3, though the actual code of Exim is entirely
363new, and has developed far beyond the initial concept.
364
365Many people, both in Cambridge and around the world, have contributed to the
366development and the testing of Exim, and to porting it to various operating
367systems. I am grateful to them all. The distribution now contains a file called
9b371988 368&_ACKNOWLEDGMENTS_&, in which I have started recording the names of
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369contributors.
370
371
f89d2485 372.section "Exim documentation" "SECID1"
800d5176 373. Keep this example change bar when updating the documentation!
b52ed2b3 374
800d5176 375.new
9b371988 376.cindex "documentation"
2aee48d6 377This edition of the Exim specification applies to version &version() of Exim.
9b371988 378Substantive changes from the &previousversion; edition are marked in some
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379renditions of the document; this paragraph is so marked if the rendition is
380capable of showing a change indicator.
800d5176 381.wen
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382
383This document is very much a reference manual; it is not a tutorial. The reader
384is expected to have some familiarity with the SMTP mail transfer protocol and
385with general Unix system administration. Although there are some discussions
386and examples in places, the information is mostly organized in a way that makes
387it easy to look up, rather than in a natural order for sequential reading.
388Furthermore, the manual aims to cover every aspect of Exim in detail, including
389a number of rarely-used, special-purpose features that are unlikely to be of
390very wide interest.
391
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392.cindex "books about Exim"
393An &"easier"& discussion of Exim which provides more in-depth explanatory,
394introductory, and tutorial material can be found in a book entitled &'The Exim
595028e4 395SMTP Mail Server'& (second edition, 2007), published by UIT Cambridge
9b371988 396(&url(http://www.uit.co.uk/exim-book/)).
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397
398This book also contains a chapter that gives a general introduction to SMTP and
399Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
400with the latest release of Exim. (Note that the earlier book about Exim,
401published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
402
9b371988 403.cindex "Debian" "information sources"
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404If you are using a Debian distribution of Exim, you will find information about
405Debian-specific features in the file
f89d2485 406&_/usr/share/doc/exim4-base/README.Debian_&.
9b371988 407The command &(man update-exim.conf)& is another source of Debian-specific
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408information.
409
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410.cindex "&_doc/NewStuff_&"
411.cindex "&_doc/ChangeLog_&"
412.cindex "change log"
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413As the program develops, there may be features in newer versions that have not
414yet made it into this document, which is updated only when the most significant
415digit of the fractional part of the version number changes. Specifications of
416new features that are not yet in this manual are placed in the file
9b371988 417&_doc/NewStuff_& in the Exim distribution.
168e428f 418
9b371988 419Some features may be classified as &"experimental"&. These may change
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420incompatibly while they are developing, or even be withdrawn. For this reason,
421they are not documented in this manual. Information about experimental features
9b371988 422can be found in the file &_doc/experimental.txt_&.
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423
424All changes to the program (whether new features, bug fixes, or other kinds of
9b371988 425change) are noted briefly in the file called &_doc/ChangeLog_&.
168e428f 426
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427.cindex "&_doc/spec.txt_&"
428This specification itself is available as an ASCII file in &_doc/spec.txt_& so
429that it can easily be searched with a text editor. Other files in the &_doc_&
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430directory are:
431
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432.table2 100pt
433.row &_OptionLists.txt_& "list of all options in alphabetical order"
434.row &_dbm.discuss.txt_& "discussion about DBM libraries"
435.row &_exim.8_& "a man page of Exim's command line options"
436.row &_experimental.txt_& "documentation of experimental features"
437.row &_filter.txt_& "specification of the filter language"
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438.row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
439.row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
440.endtable
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441
442The main specification and the specification of the filtering language are also
443available in other formats (HTML, PostScript, PDF, and Texinfo). Section
9b371988 444&<<SECTavail>>& below tells you how to get hold of these.
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445
446
447
f89d2485 448.section "FTP and web sites" "SECID2"
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449.cindex "web site"
450.cindex "FTP site"
068aaea8 451The primary site for Exim source distributions is currently the University of
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452Cambridge's FTP site, whose contents are described in &'Where to find the Exim
453distribution'& below. In addition, there is a web site and an FTP site at
454&%exim.org%&. These are now also hosted at the University of Cambridge. The
455&%exim.org%& site was previously hosted for a number of years by Energis
456Squared, formerly Planet Online Ltd, whose support I gratefully acknowledge.
457
458.cindex "wiki"
459.cindex "FAQ"
168e428f 460As well as Exim distribution tar files, the Exim web site contains a number of
f89d2485 461differently formatted versions of the documentation. A recent addition to the
7d0ab55c 462online information is the Exim wiki (&url(http://wiki.exim.org)),
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463which contains what used to be a separate FAQ, as well as various other
464examples, tips, and know-how that have been contributed by Exim users.
465
466.cindex Bugzilla
7d0ab55c 467An Exim Bugzilla exists at &url(http://bugs.exim.org). You can use
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468this to report bugs, and also to add items to the wish list. Please search
469first to check that you are not duplicating a previous entry.
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470
471
472
f89d2485 473.section "Mailing lists" "SECID3"
9b371988 474.cindex "mailing lists" "for Exim users"
f89d2485 475The following Exim mailing lists exist:
168e428f 476
9b371988 477.table2 140pt
d854d3a9 478.row &'exim-announce@exim.org'& "Moderated, low volume announcements list"
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479.row &'exim-users@exim.org'& "General discussion list"
480.row &'exim-dev@exim.org'& "Discussion of bugs, enhancements, etc."
d854d3a9 481.row &'exim-cvs@exim.org'& "Automated commit messages from the VCS"
9b371988 482.endtable
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483
484You can subscribe to these lists, change your existing subscriptions, and view
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485or search the archives via the mailing lists link on the Exim home page.
486.cindex "Debian" "mailing list for"
4f578862 487If you are using a Debian distribution of Exim, you may wish to subscribe to
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488the Debian-specific mailing list &'pkg-exim4-users@lists.alioth.debian.org'&
489via this web page:
490.display
491&url(http://lists.alioth.debian.org/mailman/listinfo/pkg-exim4-users)
492.endd
493Please ask Debian-specific questions on this list and not on the general Exim
494lists.
9b371988 495
f89d2485 496.section "Exim training" "SECID4"
9b371988 497.cindex "training courses"
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498Training courses in Cambridge (UK) used to be run annually by the author of
499Exim, before he retired. At the time of writing, there are no plans to run
500further Exim courses in Cambridge. However, if that changes, relevant
501information will be posted at &url(http://www-tus.csx.cam.ac.uk/courses/exim/).
168e428f 502
f89d2485 503.section "Bug reports" "SECID5"
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504.cindex "bug reports"
505.cindex "reporting bugs"
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506Reports of obvious bugs can be emailed to &'bugs@exim.org'& or reported
507via the Bugzilla (&url(http://bugs.exim.org)). However, if you are unsure
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508whether some behaviour is a bug or not, the best thing to do is to post a
509message to the &'exim-dev'& mailing list and have it discussed.
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510
511
512
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513.section "Where to find the Exim distribution" "SECTavail"
514.cindex "FTP site"
515.cindex "distribution" "ftp site"
168e428f 516The master ftp site for the Exim distribution is
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517.display
518&*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim*&
519.endd
168e428f 520This is mirrored by
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521.display
522&*ftp://ftp.exim.org/pub/exim*&
523.endd
524The file references that follow are relative to the &_exim_& directories at
525these sites. There are now quite a number of independent mirror sites around
526the world. Those that I know about are listed in the file called &_Mirrors_&.
527
528Within the &_exim_& directory there are subdirectories called &_exim3_& (for
529previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
530distributions), and &_Testing_& for testing versions. In the &_exim4_&
168e428f 531subdirectory, the current release can always be found in files called
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532.display
533&_exim-n.nn.tar.gz_&
534&_exim-n.nn.tar.bz2_&
535.endd
536where &'n.nn'& is the highest such version number in the directory. The two
168e428f 537files contain identical data; the only difference is the type of compression.
9b371988 538The &_.bz2_& file is usually a lot smaller than the &_.gz_& file.
168e428f 539
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540.cindex "distribution" "signing details"
541.cindex "distribution" "public key"
542.cindex "public key for signed distribution"
40167b05
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543.new
544The distributions will be PGP signed by an individual key of the Release
545Coordinator. This key will have a uid containing an email address in the
546&'exim.org'& domain and will have signatures from other people, including
547other Exim maintainers. We expect that the key will be in the "strong set" of
548PGP keys. There should be a trust path to that key from Nigel Metheringham's
549PGP key, a version of which can be found in the release directory in the file
550&_nigel-pubkey.asc_&. All keys used will be available in public keyserver pools,
551such as &'pool.sks-keyservers.net'&.
552
553At time of last update, releases were being made by Phil Pennock and signed with
554key &'0x403043153903637F'&, although that key is expected to be replaced in 2013.
555A trust path from Nigel's key to Phil's can be observed at
556&url(https://www.security.spodhuis.org/exim-trustpath).
557.wen
558
559The signatures for the tar bundles are in:
9b371988 560.display
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561&_exim-n.nn.tar.gz.asc_&
562&_exim-n.nn.tar.bz2.asc_&
9b371988 563.endd
168e428f 564For each released version, the log of changes is made separately available in a
9b371988 565separate file in the directory &_ChangeLogs_& so that it is possible to
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566find out what has changed without having to download the entire distribution.
567
9b371988 568.cindex "documentation" "available formats"
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569The main distribution contains ASCII versions of this specification and other
570documentation; other formats of the documents are available in separate files
9b371988
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571inside the &_exim4_& directory of the FTP site:
572.display
573&_exim-html-n.nn.tar.gz_&
574&_exim-pdf-n.nn.tar.gz_&
575&_exim-postscript-n.nn.tar.gz_&
576&_exim-texinfo-n.nn.tar.gz_&
577.endd
578These tar files contain only the &_doc_& directory, not the complete
579distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
168e428f 580
168e428f 581
f89d2485 582.section "Limitations" "SECID6"
9b371988
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583.ilist
584.cindex "limitations of Exim"
585.cindex "bang paths" "not handled by Exim"
586Exim is designed for use as an Internet MTA, and therefore handles addresses in
587RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
588simple two-component bang paths can be converted by a straightforward rewriting
589configuration. This restriction does not prevent Exim from being interfaced to
590UUCP as a transport mechanism, provided that domain addresses are used.
591.next
592.cindex "domainless addresses"
593.cindex "address" "without domain"
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594Exim insists that every address it handles has a domain attached. For incoming
595local messages, domainless addresses are automatically qualified with a
596configured domain value. Configuration options specify from which remote
597systems unqualified addresses are acceptable. These are then qualified on
598arrival.
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599.next
600.cindex "transport" "external"
601.cindex "external transports"
602The only external transport mechanisms that are currently implemented are SMTP
603and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
168e428f 604transport is available, and there are facilities for writing messages to files
9b371988
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605and pipes, optionally in &'batched SMTP'& format; these facilities can be used
606to send messages to other transport mechanisms such as UUCP, provided they can
607handle domain-style addresses. Batched SMTP input is also catered for.
608.next
609Exim is not designed for storing mail for dial-in hosts. When the volumes of
610such mail are large, it is better to get the messages &"delivered"& into files
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611(that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
612other means.
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613.next
614Although Exim does have basic facilities for scanning incoming messages, these
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615are not comprehensive enough to do full virus or spam scanning. Such operations
616are best carried out using additional specialized software packages. If you
617compile Exim with the content-scanning extension, straightforward interfaces to
618a number of common scanners are provided.
9b371988 619.endlist
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620
621
f89d2485 622.section "Run time configuration" "SECID7"
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623Exim's run time configuration is held in a single text file that is divided
624into a number of sections. The entries in this file consist of keywords and
625values, in the style of Smail 3 configuration files. A default configuration
626file which is suitable for simple online installations is provided in the
9b371988 627distribution, and is described in chapter &<<CHAPdefconfil>>& below.
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628
629
f89d2485 630.section "Calling interface" "SECID8"
9b371988 631.cindex "Sendmail compatibility" "command line interface"
168e428f 632Like many MTAs, Exim has adopted the Sendmail command line interface so that it
9b371988
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633can be a straight replacement for &_/usr/lib/sendmail_& or
634&_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
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635about Sendmail in order to run Exim. For actions other than sending messages,
636Sendmail-compatible options also exist, but those that produce output (for
9b371988 637example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
168e428f 638format. There are also some additional options that are compatible with Smail
9b371988 6393, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
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640documents all Exim's command line options. This information is automatically
641made into the man page that forms part of the Exim distribution.
642
643Control of messages on the queue can be done via certain privileged command
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644line options. There is also an optional monitor program called &'eximon'&,
645which displays current information in an X window, and which contains a menu
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646interface to Exim's command line administration options.
647
648
649
f89d2485 650.section "Terminology" "SECID9"
9b371988
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651.cindex "terminology definitions"
652.cindex "body of message" "definition of"
653The &'body'& of a message is the actual data that the sender wants to transmit.
654It is the last part of a message, and is separated from the &'header'& (see
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655below) by a blank line.
656
9b371988 657.cindex "bounce message" "definition of"
168e428f 658When a message cannot be delivered, it is normally returned to the sender in a
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659delivery failure message or a &"non-delivery report"& (NDR). The term
660&'bounce'& is commonly used for this action, and the error reports are often
661called &'bounce messages'&. This is a convenient shorthand for &"delivery
662failure error report"&. Such messages have an empty sender address in the
663message's &'envelope'& (see below) to ensure that they cannot themselves give
664rise to further bounce messages.
665
666The term &'default'& appears frequently in this manual. It is used to qualify a
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667value which is used in the absence of any setting in the configuration. It may
668also qualify an action which is taken unless a configuration setting specifies
669otherwise.
670
9b371988 671The term &'defer'& is used when the delivery of a message to a specific
168e428f 672destination cannot immediately take place for some reason (a remote host may be
9b371988 673down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
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674until a later time.
675
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676The word &'domain'& is sometimes used to mean all but the first component of a
677host's name. It is &'not'& used in that sense here, where it normally refers to
678the part of an email address following the @ sign.
168e428f 679
f89d2485 680.cindex "envelope, definition of"
9b371988
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681.cindex "sender" "definition of"
682A message in transit has an associated &'envelope'&, as well as a header and a
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683body. The envelope contains a sender address (to which bounce messages should
684be delivered), and any number of recipient addresses. References to the
685sender or the recipients of a message usually mean the addresses in the
686envelope. An MTA uses these addresses for delivery, and for returning bounce
687messages, not the addresses that appear in the header lines.
688
f89d2485 689.cindex "message" "header, definition of"
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690.cindex "header section" "definition of"
691The &'header'& of a message is the first part of a message's text, consisting
692of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
693&'Subject:'&, etc. Long header lines can be split over several text lines by
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694indenting the continuations. The header is separated from the body by a blank
695line.
696
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697.cindex "local part" "definition of"
698.cindex "domain" "definition of"
699The term &'local part'&, which is taken from RFC 2822, is used to refer to that
168e428f 700part of an email address that precedes the @ sign. The part that follows the
9b371988 701@ sign is called the &'domain'& or &'mail domain'&.
168e428f 702
9b371988 703.cindex "local delivery" "definition of"
f89d2485 704.cindex "remote delivery, definition of"
9b371988 705The terms &'local delivery'& and &'remote delivery'& are used to distinguish
168e428f 706delivery to a file or a pipe on the local host from delivery by SMTP over
068aaea8 707TCP/IP to another host. As far as Exim is concerned, all hosts other than the
9b371988 708host it is running on are &'remote'&.
168e428f 709
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710.cindex "return path" "definition of"
711&'Return path'& is another name that is used for the sender address in a
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712message's envelope.
713
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714.cindex "queue" "definition of"
715The term &'queue'& is used to refer to the set of messages awaiting delivery,
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716because this term is in widespread use in the context of MTAs. However, in
717Exim's case the reality is more like a pool than a queue, because there is
718normally no ordering of waiting messages.
719
9b371988
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720.cindex "queue runner" "definition of"
721The term &'queue runner'& is used to describe a process that scans the queue
168e428f 722and attempts to deliver those messages whose retry times have come. This term
9b371988 723is used by other MTAs, and also relates to the command &%runq%&, but in Exim
168e428f
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724the waiting messages are normally processed in an unpredictable order.
725
9b371988
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726.cindex "spool directory" "definition of"
727The term &'spool directory'& is used for a directory in which Exim keeps the
728messages on its queue &-- that is, those that it is in the process of
168e428f 729delivering. This should not be confused with the directory in which local
9b371988
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730mailboxes are stored, which is called a &"spool directory"& by some people. In
731the Exim documentation, &"spool"& is always used in the first sense.
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732
733
734
735
736
737
9b371988
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738. ////////////////////////////////////////////////////////////////////////////
739. ////////////////////////////////////////////////////////////////////////////
168e428f 740
f89d2485 741.chapter "Incorporated code" "CHID2"
9b371988
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742.cindex "incorporated code"
743.cindex "regular expressions" "library"
744.cindex "PCRE"
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"
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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.
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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
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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
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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
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869.next
870Many people have contributed code fragments, some large, some small, that were
168e428f 871not covered by any specific licence requirements. It is assumed that the
f89d2485 872contributors are happy to see their code incorporated into Exim under the GPL.
9b371988 873.endlist
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874
875
876
877
878
9b371988
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879. ////////////////////////////////////////////////////////////////////////////
880. ////////////////////////////////////////////////////////////////////////////
168e428f 881
f89d2485 882.chapter "How Exim receives and delivers mail" "CHID11" &&&
9b371988 883 "Receiving and delivering mail"
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884
885
f89d2485 886.section "Overall philosophy" "SECID10"
9b371988 887.cindex "design philosophy"
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888Exim is designed to work efficiently on systems that are permanently connected
889to the Internet and are handling a general mix of mail. In such circumstances,
890most messages can be delivered immediately. Consequently, Exim does not
891maintain independent queues of messages for specific domains or hosts, though
892it does try to send several messages in a single SMTP connection after a host
893has been down, and it also maintains per-host retry information.
894
895
f89d2485 896.section "Policy control" "SECID11"
9b371988 897.cindex "policy control" "overview"
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898Policy controls are now an important feature of MTAs that are connected to the
899Internet. Perhaps their most important job is to stop MTAs being abused as
9b371988
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900&"open relays"& by misguided individuals who send out vast amounts of
901unsolicited junk, and want to disguise its source. Exim provides flexible
902facilities for specifying policy controls on incoming mail:
168e428f 903
9b371988
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904.ilist
905.cindex "&ACL;" "introduction"
168e428f 906Exim 4 (unlike previous versions of Exim) implements policy controls on
9b371988 907incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
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908series of statements that may either grant or deny access. ACLs can be used at
909several places in the SMTP dialogue while receiving a message from a remote
9b371988
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910host. However, the most common places are after each RCPT command, and at the
911very end of the message. The sysadmin can specify conditions for accepting or
912rejecting individual recipients or the entire message, respectively, at these
913two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
168e428f 914error code.
9b371988
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915.next
916An ACL is also available for locally generated, non-SMTP messages. In this
168e428f 917case, the only available actions are to accept or deny the entire message.
9b371988
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918.next
919When Exim is compiled with the content-scanning extension, facilities are
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920provided in the ACL mechanism for passing the message to external virus and/or
921spam scanning software. The result of such a scan is passed back to the ACL,
922which can then use it to decide what to do with the message.
9b371988
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923.next
924When a message has been received, either from a remote host or from the local
f89d2485 925host, but before the final acknowledgment has been sent, a locally supplied C
9b371988
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926function called &[local_scan()]& can be run to inspect the message and decide
927whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
928is accepted, the list of recipients can be modified by the function.
929.next
930Using the &[local_scan()]& mechanism is another way of calling external scanner
931software. The &%SA-Exim%& add-on package works this way. It does not require
932Exim to be compiled with the content-scanning extension.
933.next
934After a message has been accepted, a further checking mechanism is available in
935the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
936runs at the start of every delivery process.
937.endlist
938
939
940
f89d2485 941.section "User filters" "SECID12"
9b371988
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942.cindex "filter" "introduction"
943.cindex "Sieve filter"
168e428f 944In a conventional Exim configuration, users are able to run private filters by
9b371988
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945setting up appropriate &_.forward_& files in their home directories. See
946chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
947configuration needed to support this, and the separate document entitled
948&'Exim's interfaces to mail filtering'& for user details. Two different kinds
949of filtering are available:
950
951.ilist
952Sieve filters are written in the standard filtering language that is defined
168e428f 953by RFC 3028.
9b371988
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954.next
955Exim filters are written in a syntax that is unique to Exim, but which is more
168e428f 956powerful than Sieve, which it pre-dates.
9b371988 957.endlist
168e428f
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958
959User filters are run as part of the routing process, described below.
960
961
962
9b371988
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963.section "Message identification" "SECTmessiden"
964.cindex "message ids" "details of format"
965.cindex "format" "of message id"
966.cindex "id of message"
967.cindex "base62"
968.cindex "base36"
969.cindex "Darwin"
970.cindex "Cygwin"
971Every message handled by Exim is given a &'message id'& which is sixteen
168e428f 972characters long. It is divided into three parts, separated by hyphens, for
9b371988 973example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
168e428f
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974normally encoding numbers in base 62. However, in the Darwin operating
975system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
976(avoiding the use of lower case letters) is used instead, because the message
977id is used to construct file names, and the names of files in those systems are
068aaea8 978not always case-sensitive.
168e428f 979
9b371988 980.cindex "pid (process id)" "re-use of"
168e428f
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981The detail of the contents of the message id have changed as Exim has evolved.
982Earlier versions relied on the operating system not re-using a process id (pid)
983within one second. On modern operating systems, this assumption can no longer
984be made, so the algorithm had to be changed. To retain backward compatibility,
985the format of the message id was retained, which is why the following rules are
986somewhat eccentric:
987
9b371988
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988.ilist
989The first six characters of the message id are the time at which the message
168e428f
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990started to be received, to a granularity of one second. That is, this field
991contains the number of seconds since the start of the epoch (the normal Unix
992way of representing the date and time of day).
9b371988
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993.next
994After the first hyphen, the next six characters are the id of the process that
168e428f 995received the message.
9b371988
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996.next
997There are two different possibilities for the final two characters:
998.olist
0a4e3112 999.oindex "&%localhost_number%&"
9b371988 1000If &%localhost_number%& is not set, this value is the fractional part of the
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1001time of reception, normally in units of 1/2000 of a second, but for systems
1002that must use base 36 instead of base 62 (because of case-insensitive file
1003systems), the units are 1/1000 of a second.
9b371988
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1004.next
1005If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
168e428f
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1006the fractional part of the time, which in this case is in units of 1/200
1007(1/100) of a second.
9b371988
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1008.endlist
1009.endlist
168e428f
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1010
1011After a message has been received, Exim waits for the clock to tick at the
1012appropriate resolution before proceeding, so that if another message is
1013received by the same process, or by another process with the same (re-used)
1014pid, it is guaranteed that the time will be different. In most cases, the clock
1015will already have ticked while the message was being received.
1016
1017
f89d2485 1018.section "Receiving mail" "SECID13"
9b371988
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1019.cindex "receiving mail"
1020.cindex "message" "reception"
068aaea8
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1021The only way Exim can receive mail from another host is using SMTP over
1022TCP/IP, in which case the sender and recipient addresses are transferred using
168e428f
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1023SMTP commands. However, from a locally running process (such as a user's MUA),
1024there are several possibilities:
1025
9b371988
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1026.ilist
1027If the process runs Exim with the &%-bm%& option, the message is read
168e428f 1028non-interactively (usually via a pipe), with the recipients taken from the
9b371988
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1029command line, or from the body of the message if &%-t%& is also used.
1030.next
1031If the process runs Exim with the &%-bS%& option, the message is also read
168e428f
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1032non-interactively, but in this case the recipients are listed at the start of
1033the message in a series of SMTP RCPT commands, terminated by a DATA
9b371988 1034command. This is so-called &"batch SMTP"& format,
168e428f
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1035but it isn't really SMTP. The SMTP commands are just another way of passing
1036envelope addresses in a non-interactive submission.
9b371988
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1037.next
1038If the process runs Exim with the &%-bs%& option, the message is read
168e428f
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1039interactively, using the SMTP protocol. A two-way pipe is normally used for
1040passing data between the local process and the Exim process.
9b371988 1041This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
168e428f 1042example, the ACLs for SMTP commands are used for this form of submission.
9b371988
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1043.next
1044A local process may also make a TCP/IP call to the host's loopback address
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1045(127.0.0.1) or any other of its IP addresses. When receiving messages, Exim
1046does not treat the loopback address specially. It treats all such connections
1047in the same way as connections from other hosts.
9b371988 1048.endlist
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1049
1050
f89d2485 1051.cindex "message sender, constructed by Exim"
9b371988 1052.cindex "sender" "constructed by Exim"
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1053In the three cases that do not involve TCP/IP, the sender address is
1054constructed from the login name of the user that called Exim and a default
9b371988 1055qualification domain (which can be set by the &%qualify_domain%& configuration
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1056option). For local or batch SMTP, a sender address that is passed using the
1057SMTP MAIL command is ignored. However, the system administrator may allow
9b371988 1058certain users (&"trusted users"&) to specify a different sender address
168e428f 1059unconditionally, or all users to specify certain forms of different sender
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1060address. The &%-f%& option or the SMTP MAIL command is used to specify these
1061different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1062users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
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1063users to change sender addresses.
1064
1065Messages received by either of the non-interactive mechanisms are subject to
1066checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1067(either over TCP/IP, or interacting with a local process) can be checked by a
1068number of ACLs that operate at different times during the SMTP session. Either
1069individual recipients, or the entire message, can be rejected if local policy
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1070requirements are not met. The &[local_scan()]& function (see chapter
1071&<<CHAPlocalscan>>&) is run for all incoming messages.
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1072
1073Exim can be configured not to start a delivery process when a message is
1074received; this can be unconditional, or depend on the number of incoming SMTP
1075connections or the system load. In these situations, new messages wait on the
1076queue until a queue runner process picks them up. However, in standard
1077configurations under normal conditions, delivery is started as soon as a
1078message is received.
1079
1080
1081
1082
1083
f89d2485 1084.section "Handling an incoming message" "SECID14"
9b371988
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1085.cindex "spool directory" "files that hold a message"
1086.cindex "file" "how a message is held"
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1087When Exim accepts a message, it writes two files in its spool directory. The
1088first contains the envelope information, the current status of the message, and
1089the header lines, and the second contains the body of the message. The names of
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1090the two spool files consist of the message id, followed by &`-H`& for the
1091file containing the envelope and header, and &`-D`& for the data file.
168e428f 1092
9b371988 1093.cindex "spool directory" "&_input_& sub-directory"
168e428f 1094By default all these message files are held in a single directory called
9b371988 1095&_input_& inside the general Exim spool directory. Some operating systems do
c0712871 1096not perform very well if the number of files in a directory gets large; to
9b371988 1097improve performance in such cases, the &%split_spool_directory%& option can be
168e428f 1098used. This causes Exim to split up the input files into 62 sub-directories
db9452a9 1099whose names are single letters or digits. When this is done, the queue is
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1100processed one sub-directory at a time instead of all at once, which can improve
1101overall performance even when there are not enough files in each directory to
db9452a9 1102affect file system performance.
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1103
1104The envelope information consists of the address of the message's sender and
1105the addresses of the recipients. This information is entirely separate from
1106any addresses contained in the header lines. The status of the message includes
1107a list of recipients who have already received the message. The format of the
9b371988 1108first spool file is described in chapter &<<CHAPspool>>&.
168e428f 1109
9b371988 1110.cindex "rewriting" "addresses"
168e428f 1111Address rewriting that is specified in the rewrite section of the configuration
9b371988 1112(see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
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1113both in the header lines and the envelope, at the time the message is accepted.
1114If during the course of delivery additional addresses are generated (for
1115example, via aliasing), these new addresses are rewritten as soon as they are
1116generated. At the time a message is actually delivered (transported) further
1117rewriting can take place; because this is a transport option, it can be
1118different for different forms of delivery. It is also possible to specify the
1119addition or removal of certain header lines at the time the message is
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1120delivered (see chapters &<<CHAProutergeneric>>& and
1121&<<CHAPtransportgeneric>>&).
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1122
1123
1124
f89d2485 1125.section "Life of a message" "SECID15"
9b371988
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1126.cindex "message" "life of"
1127.cindex "message" "frozen"
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1128A message remains in the spool directory until it is completely delivered to
1129its recipients or to an error address, or until it is deleted by an
1130administrator or by the user who originally created it. In cases when delivery
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1131cannot proceed &-- for example, when a message can neither be delivered to its
1132recipients nor returned to its sender, the message is marked &"frozen"& on the
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1133spool, and no more deliveries are attempted.
1134
9b371988
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1135.cindex "frozen messages" "thawing"
1136.cindex "message" "thawing frozen"
1137An administrator can &"thaw"& such messages when the problem has been
1138corrected, and can also freeze individual messages by hand if necessary. In
1139addition, an administrator can force a delivery error, causing a bounce message
1140to be sent.
1141
0a4e3112
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1142.oindex "&%timeout_frozen_after%&"
1143.oindex "&%ignore_bounce_errors_after%&"
9b371988
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1144There are options called &%ignore_bounce_errors_after%& and
1145&%timeout_frozen_after%&, which discard frozen messages after a certain time.
068aaea8 1146The first applies only to frozen bounces, the second to any frozen messages.
168e428f 1147
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1148.cindex "message" "log file for"
1149.cindex "log" "file for each message"
168e428f 1150While Exim is working on a message, it writes information about each delivery
068aaea8 1151attempt to its main log file. This includes successful, unsuccessful, and
9b371988
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1152delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1153lines are also written to a separate &'message log'& file for each message.
1154These logs are solely for the benefit of the administrator, and are normally
1155deleted along with the spool files when processing of a message is complete.
168e428f 1156The use of individual message logs can be disabled by setting
9b371988
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1157&%no_message_logs%&; this might give an improvement in performance on very busy
1158systems.
168e428f 1159
9b371988
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1160.cindex "journal file"
1161.cindex "file" "journal"
168e428f
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1162All the information Exim itself needs to set up a delivery is kept in the first
1163spool file, along with the header lines. When a successful delivery occurs, the
1164address is immediately written at the end of a journal file, whose name is the
9b371988
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1165message id followed by &`-J`&. At the end of a delivery run, if there are some
1166addresses left to be tried again later, the first spool file (the &`-H`& file)
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1167is updated to indicate which these are, and the journal file is then deleted.
1168Updating the spool file is done by writing a new file and renaming it, to
1169minimize the possibility of data loss.
1170
1171Should the system or the program crash after a successful delivery but before
1172the spool file has been updated, the journal is left lying around. The next
1173time Exim attempts to deliver the message, it reads the journal file and
1174updates the spool file before proceeding. This minimizes the chances of double
1175deliveries caused by crashes.
1176
1177
1178
9b371988
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1179.section "Processing an address for delivery" "SECTprocaddress"
1180.cindex "drivers" "definition of"
1181.cindex "router" "definition of"
1182.cindex "transport" "definition of"
1183The main delivery processing elements of Exim are called &'routers'& and
1184&'transports'&, and collectively these are known as &'drivers'&. Code for a
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1185number of them is provided in the source distribution, and compile-time options
1186specify which ones are included in the binary. Run time options specify which
1187ones are actually used for delivering messages.
1188
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1189.cindex "drivers" "instance definition"
1190Each driver that is specified in the run time configuration is an &'instance'&
168e428f 1191of that particular driver type. Multiple instances are allowed; for example,
9b371988 1192you can set up several different &(smtp)& transports, each with different
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1193option values that might specify different ports or different timeouts. Each
1194instance has its own identifying name. In what follows we will normally use the
1195instance name when discussing one particular instance (that is, one specific
1196configuration of the driver), and the generic driver name when discussing
1197the driver's features in general.
1198
9b371988 1199A &'router'& is a driver that operates on an address, either determining how
068aaea8 1200its delivery should happen, by assigning it to a specific transport, or
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1201converting the address into one or more new addresses (for example, via an
1202alias file). A router may also explicitly choose to fail an address, causing it
1203to be bounced.
1204
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1205A &'transport'& is a driver that transmits a copy of the message from Exim's
1206spool to some destination. There are two kinds of transport: for a &'local'&
168e428f 1207transport, the destination is a file or a pipe on the local host, whereas for a
9b371988 1208&'remote'& transport the destination is some other host. A message is passed
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1209to a specific transport as a result of successful routing. If a message has
1210several recipients, it may be passed to a number of different transports.
1211
9b371988 1212.cindex "preconditions" "definition of"
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1213An address is processed by passing it to each configured router instance in
1214turn, subject to certain preconditions, until a router accepts the address or
1215specifies that it should be bounced. We will describe this process in more
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1216detail shortly. First, as a simple example, we consider how each recipient
1217address in a message is processed in a small configuration of three routers.
168e428f 1218
068aaea8 1219To make this a more concrete example, it is described in terms of some actual
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1220routers, but remember, this is only an example. You can configure Exim's
1221routers in many different ways, and there may be any number of routers in a
1222configuration.
1223
1224The first router that is specified in a configuration is often one that handles
1225addresses in domains that are not recognized specially by the local host. These
1226are typically addresses for arbitrary domains on the Internet. A precondition
1227is set up which looks for the special domains known to the host (for example,
9b371988 1228its own domain name), and the router is run for addresses that do &'not'&
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1229match. Typically, this is a router that looks up domains in the DNS in order to
1230find the hosts to which this address routes. If it succeeds, the address is
068aaea8 1231assigned to a suitable SMTP transport; if it does not succeed, the router is
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1232configured to fail the address.
1233
068aaea8 1234The second router is reached only when the domain is recognized as one that
9b371988 1235&"belongs"& to the local host. This router does redirection &-- also known as
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1236aliasing and forwarding. When it generates one or more new addresses from the
1237original, each of them is routed independently from the start. Otherwise, the
1238router may cause an address to fail, or it may simply decline to handle the
1239address, in which case the address is passed to the next router.
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1240
1241The final router in many configurations is one that checks to see if the
1242address belongs to a local mailbox. The precondition may involve a check to
1243see if the local part is the name of a login account, or it may look up the
1244local part in a file or a database. If its preconditions are not met, or if
1245the router declines, we have reached the end of the routers. When this happens,
1246the address is bounced.
1247
1248
1249
f89d2485 1250.section "Processing an address for verification" "SECID16"
9b371988
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1251.cindex "router" "for verification"
1252.cindex "verifying address" "overview"
168e428f 1253As well as being used to decide how to deliver to an address, Exim's routers
9b371988 1254are also used for &'address verification'&. Verification can be requested as
168e428f 1255one of the checks to be performed in an ACL for incoming messages, on both
9b371988
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1256sender and recipient addresses, and it can be tested using the &%-bv%& and
1257&%-bvs%& command line options.
168e428f 1258
9b371988 1259When an address is being verified, the routers are run in &"verify mode"&. This
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1260does not affect the way the routers work, but it is a state that can be
1261detected. By this means, a router can be skipped or made to behave differently
1262when verifying. A common example is a configuration in which the first router
1263sends all messages to a message-scanning program, unless they have been
1264previously scanned. Thus, the first router accepts all addresses without any
9b371988 1265checking, making it useless for verifying. Normally, the &%no_verify%& option
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1266would be set for such a router, causing it to be skipped in verify mode.
1267
1268
1269
1270
9b371988
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1271.section "Running an individual router" "SECTrunindrou"
1272.cindex "router" "running details"
1273.cindex "preconditions" "checking"
1274.cindex "router" "result of running"
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1275As explained in the example above, a number of preconditions are checked before
1276running a router. If any are not met, the router is skipped, and the address is
9b371988 1277passed to the next router. When all the preconditions on a router &'are'& met,
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1278the router is run. What happens next depends on the outcome, which is one of
1279the following:
1280
9b371988
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1281.ilist
1282&'accept'&: The router accepts the address, and either assigns it to a
1283transport, or generates one or more &"child"& addresses. Processing the
1284original address ceases,
0a4e3112 1285.oindex "&%unseen%&"
9b371988 1286unless the &%unseen%& option is set on the router. This option
168e428f 1287can be used to set up multiple deliveries with different routing (for example,
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1288for keeping archive copies of messages). When &%unseen%& is set, the address is
1289passed to the next router. Normally, however, an &'accept'& return marks the
168e428f 1290end of routing.
9b371988 1291
068aaea8
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1292Any child addresses generated by the router are processed independently,
1293starting with the first router by default. It is possible to change this by
9b371988
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1294setting the &%redirect_router%& option to specify which router to start at for
1295child addresses. Unlike &%pass_router%& (see below) the router specified by
1296&%redirect_router%& may be anywhere in the router configuration.
1297.next
1298&'pass'&: The router recognizes the address, but cannot handle it itself. It
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1299requests that the address be passed to another router. By default the address
1300is passed to the next router, but this can be changed by setting the
9b371988 1301&%pass_router%& option. However, (unlike &%redirect_router%&) the named router
168e428f 1302must be below the current router (to avoid loops).
9b371988
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1303.next
1304&'decline'&: The router declines to accept the address because it does not
168e428f 1305recognize it at all. By default, the address is passed to the next router, but
9b371988
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1306this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1307set, all the remaining routers are skipped. In effect, &%no_more%& converts
1308&'decline'& into &'fail'&.
1309.next
1310&'fail'&: The router determines that the address should fail, and queues it for
168e428f 1311the generation of a bounce message. There is no further processing of the
9b371988
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1312original address unless &%unseen%& is set on the router.
1313.next
1314&'defer'&: The router cannot handle the address at the present time. (A
068aaea8
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1315database may be offline, or a DNS lookup may have timed out.) No further
1316processing of the address happens in this delivery attempt. It is tried again
1317next time the message is considered for delivery.
9b371988
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1318.next
1319&'error'&: There is some error in the router (for example, a syntax error in
168e428f 1320its configuration). The action is as for defer.
9b371988 1321.endlist
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1322
1323If an address reaches the end of the routers without having been accepted by
068aaea8 1324any of them, it is bounced as unrouteable. The default error message in this
9b371988
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1325situation is &"unrouteable address"&, but you can set your own message by
1326making use of the &%cannot_route_message%& option. This can be set for any
1327router; the value from the last router that &"saw"& the address is used.
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1328
1329Sometimes while routing you want to fail a delivery when some conditions are
1330met but others are not, instead of passing the address on for further routing.
1331You can do this by having a second router that explicitly fails the delivery
9b371988 1332when the relevant conditions are met. The &(redirect)& router has a &"fail"&
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1333facility for this purpose.
1334
1335
f89d2485 1336.section "Duplicate addresses" "SECID17"
9b371988 1337.cindex "case of local parts"
f89d2485 1338.cindex "address duplicate, discarding"
db9452a9 1339.cindex "duplicate addresses"
068aaea8
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1340Once routing is complete, Exim scans the addresses that are assigned to local
1341and remote transports, and discards any duplicates that it finds. During this
3cb1b51e 1342check, local parts are treated as case-sensitive. This happens only when
db9452a9 1343actually delivering a message; when testing routers with &%-bt%&, all the
3cb1b51e 1344routed addresses are shown.
db9452a9 1345
068aaea8 1346
168e428f 1347
9b371988 1348.section "Router preconditions" "SECTrouprecon"
f89d2485 1349.cindex "router" "preconditions, order of processing"
9b371988 1350.cindex "preconditions" "order of processing"
168e428f
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1351The preconditions that are tested for each router are listed below, in the
1352order in which they are tested. The individual configuration options are
9b371988 1353described in more detail in chapter &<<CHAProutergeneric>>&.
168e428f 1354
9b371988
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1355.ilist
1356The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
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1357the local parts handled by the router may or must have certain prefixes and/or
1358suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1359skipped. These conditions are tested first. When an affix is present, it is
1360removed from the local part before further processing, including the evaluation
1361of any other conditions.
9b371988
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1362.next
1363Routers can be designated for use only when not verifying an address, that is,
168e428f 1364only when routing it for delivery (or testing its delivery routing). If the
9b371988 1365&%verify%& option is set false, the router is skipped when Exim is verifying an
168e428f 1366address.
9b371988
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1367Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1368&%verify_recipient%&, which independently control the use of the router for
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1369sender and recipient verification. You can set these options directly if
1370you want a router to be used for only one type of verification.
5b0cf788
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1371Note that cutthrough delivery is classed as a recipient verification
1372for this purpose.
9b371988
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1373.next
1374If the &%address_test%& option is set false, the router is skipped when Exim is
1375run with the &%-bt%& option to test an address routing. This can be helpful
1376when the first router sends all new messages to a scanner of some sort; it
1377makes it possible to use &%-bt%& to test subsequent delivery routing without
1378having to simulate the effect of the scanner.
1379.next
1380Routers can be designated for use only when verifying an address, as
1381opposed to routing it for delivery. The &%verify_only%& option controls this.
5b0cf788 1382Again, cutthrough delibery counts as a verification.
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1383.next
1384Individual routers can be explicitly skipped when running the routers to
1385check an address given in the SMTP EXPN command (see the &%expn%& option).
1386.next
1387If the &%domains%& option is set, the domain of the address must be in the set
068aaea8 1388of domains that it defines.
9b371988 1389.next
f89d2485
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1390.vindex "&$local_part_prefix$&"
1391.vindex "&$local_part$&"
1392.vindex "&$local_part_suffix$&"
9b371988
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1393If the &%local_parts%& option is set, the local part of the address must be in
1394the set of local parts that it defines. If &%local_part_prefix%& or
1395&%local_part_suffix%& is in use, the prefix or suffix is removed from the local
168e428f 1396part before this check. If you want to do precondition tests on local parts
9b371988
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1397that include affixes, you can do so by using a &%condition%& option (see below)
1398that uses the variables &$local_part$&, &$local_part_prefix$&, and
1399&$local_part_suffix$& as necessary.
1400.next
f89d2485
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1401.vindex "&$local_user_uid$&"
1402.vindex "&$local_user_gid$&"
1403.vindex "&$home$&"
9b371988 1404If the &%check_local_user%& option is set, the local part must be the name of
068aaea8 1405an account on the local host. If this check succeeds, the uid and gid of the
9b371988
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1406local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1407user's home directory is placed in &$home$&; these values can be used in the
1408remaining preconditions.
1409.next
1410If the &%router_home_directory%& option is set, it is expanded at this point,
1411because it overrides the value of &$home$&. If this expansion were left till
1412later, the value of &$home$& as set by &%check_local_user%& would be used in
1413subsequent tests. Having two different values of &$home$& in the same router
168e428f 1414could lead to confusion.
9b371988
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1415.next
1416If the &%senders%& option is set, the envelope sender address must be in the
1417set of addresses that it defines.
1418.next
1419If the &%require_files%& option is set, the existence or non-existence of
168e428f 1420specified files is tested.
9b371988
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1421.next
1422.cindex "customizing" "precondition"
1423If the &%condition%& option is set, it is evaluated and tested. This option
1424uses an expanded string to allow you to set up your own custom preconditions.
1425Expanded strings are described in chapter &<<CHAPexpand>>&.
1426.endlist
168e428f 1427
168e428f 1428
9b371988
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1429Note that &%require_files%& comes near the end of the list, so you cannot use
1430it to check for the existence of a file in which to lookup up a domain, local
168e428f 1431part, or sender. However, as these options are all expanded, you can use the
9b371988
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1432&%exists%& expansion condition to make such tests within each condition. The
1433&%require_files%& option is intended for checking files that the router may be
168e428f 1434going to use internally, or which are needed by a specific transport (for
9b371988 1435example, &_.procmailrc_&).
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1436
1437
1438
f89d2485 1439.section "Delivery in detail" "SECID18"
9b371988 1440.cindex "delivery" "in detail"
168e428f
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1441When a message is to be delivered, the sequence of events is as follows:
1442
9b371988
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1443.ilist
1444If a system-wide filter file is specified, the message is passed to it. The
168e428f
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1445filter may add recipients to the message, replace the recipients, discard the
1446message, cause a new message to be generated, or cause the message delivery to
1447fail. The format of the system filter file is the same as for Exim user filter
9b371988
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1448files, described in the separate document entitled &'Exim's interfaces to mail
1449filtering'&.
1450.cindex "Sieve filter" "not available for system filter"
1451(&*Note*&: Sieve cannot be used for system filter files.)
1452
1453Some additional features are available in system filters &-- see chapter
1454&<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
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1455filter only once per delivery attempt, however many recipients it has. However,
1456if there are several delivery attempts because one or more addresses could not
1457be immediately delivered, the system filter is run each time. The filter
9b371988 1458condition &%first_delivery%& can be used to detect the first run of the system
168e428f 1459filter.
9b371988
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1460.next
1461Each recipient address is offered to each configured router in turn, subject to
1462its preconditions, until one is able to handle it. If no router can handle the
1463address, that is, if they all decline, the address is failed. Because routers
1464can be targeted at particular domains, several locally handled domains can be
1465processed entirely independently of each other.
1466.next
1467.cindex "routing" "loops in"
1468.cindex "loop" "while routing"
1469A router that accepts an address may assign it to a local or a remote
1470transport. However, the transport is not run at this time. Instead, the address
1471is placed on a list for the particular transport, which will be run later.
068aaea8
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1472Alternatively, the router may generate one or more new addresses (typically
1473from alias, forward, or filter files). New addresses are fed back into this
1474process from the top, but in order to avoid loops, a router ignores any address
1475which has an identically-named ancestor that was processed by itself.
9b371988
PH
1476.next
1477When all the routing has been done, addresses that have been successfully
168e428f
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1478handled are passed to their assigned transports. When local transports are
1479doing real local deliveries, they handle only one address at a time, but if a
1480local transport is being used as a pseudo-remote transport (for example, to
1481collect batched SMTP messages for transmission by some other means) multiple
1482addresses can be handled. Remote transports can always handle more than one
1483address at a time, but can be configured not to do so, or to restrict multiple
1484addresses to the same domain.
9b371988
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1485.next
1486Each local delivery to a file or a pipe runs in a separate process under a
168e428f
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1487non-privileged uid, and these deliveries are run one at a time. Remote
1488deliveries also run in separate processes, normally under a uid that is private
9b371988 1489to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
168e428f 1490run in parallel. The maximum number of simultaneous remote deliveries for any
9b371988 1491one message is set by the &%remote_max_parallel%& option.
168e428f
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1492The order in which deliveries are done is not defined, except that all local
1493deliveries happen before any remote deliveries.
9b371988
PH
1494.next
1495.cindex "queue runner"
168e428f
PH
1496When it encounters a local delivery during a queue run, Exim checks its retry
1497database to see if there has been a previous temporary delivery failure for the
1498address before running the local transport. If there was a previous failure,
1499Exim does not attempt a new delivery until the retry time for the address is
1500reached. However, this happens only for delivery attempts that are part of a
1501queue run. Local deliveries are always attempted when delivery immediately
1502follows message reception, even if retry times are set for them. This makes for
1503better behaviour if one particular message is causing problems (for example,
1504causing quota overflow, or provoking an error in a filter file).
9b371988
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1505.next
1506.cindex "delivery" "retry in remote transports"
168e428f
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1507Remote transports do their own retry handling, since an address may be
1508deliverable to one of a number of hosts, each of which may have a different
1509retry time. If there have been previous temporary failures and no host has
1510reached its retry time, no delivery is attempted, whether in a queue run or
9b371988
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1511not. See chapter &<<CHAPretry>>& for details of retry strategies.
1512.next
1513If there were any permanent errors, a bounce message is returned to an
168e428f
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1514appropriate address (the sender in the common case), with details of the error
1515for each failing address. Exim can be configured to send copies of bounce
1516messages to other addresses.
9b371988
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1517.next
1518.cindex "delivery" "deferral"
168e428f
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1519If one or more addresses suffered a temporary failure, the message is left on
1520the queue, to be tried again later. Delivery of these addresses is said to be
9b371988
PH
1521&'deferred'&.
1522.next
1523When all the recipient addresses have either been delivered or bounced,
168e428f
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1524handling of the message is complete. The spool files and message log are
1525deleted, though the message log can optionally be preserved if required.
9b371988 1526.endlist
168e428f
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1527
1528
1529
1530
f89d2485 1531.section "Retry mechanism" "SECID19"
9b371988
PH
1532.cindex "delivery" "retry mechanism"
1533.cindex "retry" "description of mechanism"
1534.cindex "queue runner"
168e428f
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1535Exim's mechanism for retrying messages that fail to get delivered at the first
1536attempt is the queue runner process. You must either run an Exim daemon that
9b371988
PH
1537uses the &%-q%& option with a time interval to start queue runners at regular
1538intervals, or use some other means (such as &'cron'&) to start them. If you do
168e428f
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1539not arrange for queue runners to be run, messages that fail temporarily at the
1540first attempt will remain on your queue for ever. A queue runner process works
068aaea8 1541its way through the queue, one message at a time, trying each delivery that has
168e428f
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1542passed its retry time.
1543You can run several queue runners at once.
1544
1545Exim uses a set of configured rules to determine when next to retry the failing
9b371988
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1546address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1547should give up trying to deliver to the address, at which point it generates a
1548bounce message. If no retry rules are set for a particular host, address, and
1549error combination, no retries are attempted, and temporary errors are treated
1550as permanent.
168e428f
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1551
1552
1553
f89d2485 1554.section "Temporary delivery failure" "SECID20"
9b371988 1555.cindex "delivery" "temporary failure"
168e428f
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1556There are many reasons why a message may not be immediately deliverable to a
1557particular address. Failure to connect to a remote machine (because it, or the
1558connection to it, is down) is one of the most common. Temporary failures may be
1559detected during routing as well as during the transport stage of delivery.
1560Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1561is on a file system where the user is over quota. Exim can be configured to
1562impose its own quotas on local mailboxes; where system quotas are set they will
1563also apply.
1564
1565If a host is unreachable for a period of time, a number of messages may be
1566waiting for it by the time it recovers, and sending them in a single SMTP
1567connection is clearly beneficial. Whenever a delivery to a remote host is
1568deferred,
9b371988 1569.cindex "hints database"
168e428f
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1570Exim makes a note in its hints database, and whenever a successful
1571SMTP delivery has happened, it looks to see if any other messages are waiting
1572for the same host. If any are found, they are sent over the same SMTP
1573connection, subject to a configuration limit as to the maximum number in any
1574one connection.
168e428f
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1575
1576
1577
f89d2485 1578.section "Permanent delivery failure" "SECID21"
9b371988
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1579.cindex "delivery" "permanent failure"
1580.cindex "bounce message" "when generated"
168e428f
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1581When a message cannot be delivered to some or all of its intended recipients, a
1582bounce message is generated. Temporary delivery failures turn into permanent
1583errors when their timeout expires. All the addresses that fail in a given
1584delivery attempt are listed in a single message. If the original message has
1585many recipients, it is possible for some addresses to fail in one delivery
1586attempt and others to fail subsequently, giving rise to more than one bounce
1587message. The wording of bounce messages can be customized by the administrator.
9b371988 1588See chapter &<<CHAPemsgcust>>& for details.
168e428f 1589
9b371988
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1590.cindex "&'X-Failed-Recipients:'& header line"
1591Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
168e428f
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1592failed addresses, for the benefit of programs that try to analyse such messages
1593automatically.
1594
9b371988 1595.cindex "bounce message" "recipient of"
168e428f
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1596A bounce message is normally sent to the sender of the original message, as
1597obtained from the message's envelope. For incoming SMTP messages, this is the
9b371988
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1598address given in the MAIL command. However, when an address is expanded via a
1599forward or alias file, an alternative address can be specified for delivery
1600failures of the generated addresses. For a mailing list expansion (see section
1601&<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1602of the list.
168e428f
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1603
1604
1605
f89d2485 1606.section "Failures to deliver bounce messages" "SECID22"
9b371988 1607.cindex "bounce message" "failure to deliver"
168e428f
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1608If a bounce message (either locally generated or received from a remote host)
1609itself suffers a permanent delivery failure, the message is left on the queue,
1610but it is frozen, awaiting the attention of an administrator. There are options
068aaea8 1611that can be used to make Exim discard such failed messages, or to keep them
9b371988
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1612for only a short time (see &%timeout_frozen_after%& and
1613&%ignore_bounce_errors_after%&).
168e428f
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1614
1615
1616
1617
1618
9b371988
PH
1619. ////////////////////////////////////////////////////////////////////////////
1620. ////////////////////////////////////////////////////////////////////////////
168e428f 1621
f89d2485 1622.chapter "Building and installing Exim" "CHID3"
4f578862 1623.scindex IIDbuex "building Exim"
168e428f 1624
f89d2485
PH
1625.section "Unpacking" "SECID23"
1626Exim is distributed as a gzipped or bzipped tar file which, when unpacked,
168e428f 1627creates a directory with the name of the current release (for example,
2aee48d6 1628&_exim-&version()_&) into which the following files are placed:
9b371988
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1629
1630.table2 140pt
f89d2485
PH
1631.irow &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1632.irow &_CHANGES_& "contains a reference to where changes are &&&
1633 documented"
1634.irow &_LICENCE_& "the GNU General Public Licence"
1635.irow &_Makefile_& "top-level make file"
1636.irow &_NOTICE_& "conditions for the use of Exim"
1637.irow &_README_& "list of files, directories and simple build &&&
1638 instructions"
9b371988
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1639.endtable
1640
1641Other files whose names begin with &_README_& may also be present. The
168e428f
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1642following subdirectories are created:
1643
9b371988 1644.table2 140pt
f89d2485
PH
1645.irow &_Local_& "an empty directory for local configuration files"
1646.irow &_OS_& "OS-specific files"
1647.irow &_doc_& "documentation files"
1648.irow &_exim_monitor_& "source files for the Exim monitor"
1649.irow &_scripts_& "scripts used in the build process"
1650.irow &_src_& "remaining source files"
1651.irow &_util_& "independent utilities"
9b371988
PH
1652.endtable
1653
1654The main utility programs are contained in the &_src_& directory, and are built
1655with the Exim binary. The &_util_& directory contains a few optional scripts
168e428f
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1656that may be useful to some sites.
1657
1658
f89d2485 1659.section "Multiple machine architectures and operating systems" "SECID24"
9b371988 1660.cindex "building Exim" "multiple OS/architectures"
168e428f
PH
1661The building process for Exim is arranged to make it easy to build binaries for
1662a number of different architectures and operating systems from the same set of
9b371988
PH
1663source files. Compilation does not take place in the &_src_& directory.
1664Instead, a &'build directory'& is created for each architecture and operating
1665system.
1666.cindex "symbolic link" "to build directory"
168e428f 1667Symbolic links to the sources are installed in this directory, which is where
9b371988
PH
1668the actual building takes place. In most cases, Exim can discover the machine
1669architecture and operating system for itself, but the defaults can be
1670overridden if necessary.
168e428f 1671
168e428f 1672
8473d4ee 1673.section "PCRE library" "SECTpcre"
210f147e
NM
1674.cindex "PCRE library"
1675Exim no longer has an embedded PCRE library as the vast majority of
1676modern systems include PCRE as a system library, although you may need
1677to install the PCRE or PCRE development package for your operating
1678system. If your system has a normal PCRE installation the Exim build
1679process will need no further configuration. If the library or the
6a6084f8
PP
1680headers are in an unusual location you will need to either set the PCRE_LIBS
1681and INCLUDE directives appropriately,
1682or set PCRE_CONFIG=yes to use the installed &(pcre-config)& command.
1683If your operating system has no
210f147e
NM
1684PCRE support then you will need to obtain and build the current PCRE
1685from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/).
6a6084f8 1686More information on PCRE is available at &url(http://www.pcre.org/).
210f147e 1687
9b371988
PH
1688.section "DBM libraries" "SECTdb"
1689.cindex "DBM libraries" "discussion of"
1690.cindex "hints database" "DBM files used for"
168e428f
PH
1691Even if you do not use any DBM files in your configuration, Exim still needs a
1692DBM library in order to operate, because it uses indexed files for its hints
1693databases. Unfortunately, there are a number of DBM libraries in existence, and
1694different operating systems often have different ones installed.
1695
9b371988 1696.cindex "Solaris" "DBM library for"
f89d2485
PH
1697.cindex "IRIX, DBM library for"
1698.cindex "BSD, DBM library for"
1699.cindex "Linux, DBM library for"
168e428f
PH
1700If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1701Linux distribution, the DBM configuration should happen automatically, and you
1702may be able to ignore this section. Otherwise, you may have to learn more than
1703you would like about DBM libraries from what follows.
1704
9b371988 1705.cindex "&'ndbm'& DBM library"
168e428f 1706Licensed versions of Unix normally contain a library of DBM functions operating
9b371988 1707via the &'ndbm'& interface, and this is what Exim expects by default. Free
168e428f
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1708versions of Unix seem to vary in what they contain as standard. In particular,
1709some early versions of Linux have no default DBM library, and different
1710distributors have chosen to bundle different libraries with their packaged
f89d2485 1711versions. However, the more recent releases seem to have standardized on the
168e428f
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1712Berkeley DB library.
1713
1714Different DBM libraries have different conventions for naming the files they
9b371988 1715use. When a program opens a file called &_dbmfile_&, there are several
168e428f
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1716possibilities:
1717
9b371988
PH
1718.olist
1719A traditional &'ndbm'& implementation, such as that supplied as part of
1720Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1721.next
1722.cindex "&'gdbm'& DBM library"
1723The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
168e428f 1724compatibility interface it makes two different hard links to it with names
9b371988 1725&_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
168e428f 1726file name is used unmodified.
9b371988
PH
1727.next
1728.cindex "Berkeley DB library"
1729The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1730operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1731programmer exactly the same as the traditional &'ndbm'& implementation.
1732.next
1733If the Berkeley package is used in its native mode, it operates on a single
1734file called &_dbmfile_&; the programmer's interface is somewhat different to
1735the traditional &'ndbm'& interface.
1736.next
1737To complicate things further, there are several very different versions of the
168e428f 1738Berkeley DB package. Version 1.85 was stable for a very long time, releases
9b371988
PH
17392.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1740numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
168e428f 1741versions of Berkeley DB can be obtained from
9b371988
PH
1742&url(http://www.sleepycat.com/).
1743.next
1744.cindex "&'tdb'& DBM library"
1745Yet another DBM library, called &'tdb'&, is available from
1746&url(http://download.sourceforge.net/tdb). It has its own interface, and also
1747operates on a single file.
1748.endlist
1749
1750.cindex "USE_DB"
1751.cindex "DBM libraries" "configuration for building"
168e428f
PH
1752Exim and its utilities can be compiled to use any of these interfaces. In order
1753to use any version of the Berkeley DB package in native mode, you must set
1754USE_DB in an appropriate configuration file (typically
9b371988
PH
1755&_Local/Makefile_&). For example:
1756.code
1757USE_DB=yes
1758.endd
168e428f
PH
1759Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1760error is diagnosed if you set more than one of these.
1761
1762At the lowest level, the build-time configuration sets none of these options,
1763thereby assuming an interface of type (1). However, some operating system
1764configuration files (for example, those for the BSD operating systems and
1765Linux) assume type (4) by setting USE_DB as their default, and the
1766configuration files for Cygwin set USE_GDBM. Anything you set in
9b371988 1767&_Local/Makefile_&, however, overrides these system defaults.
168e428f
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1768
1769As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1770necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1771in one of these lines:
9b371988
PH
1772.code
1773DBMLIB = -ldb
1774DBMLIB = -ltdb
1775.endd
168e428f
PH
1776Settings like that will work if the DBM library is installed in the standard
1777place. Sometimes it is not, and the library's header file may also not be in
1778the default path. You may need to set INCLUDE to specify where the header
1779file is, and to specify the path to the library more fully in DBMLIB, as in
1780this example:
9b371988
PH
1781.code
1782INCLUDE=-I/usr/local/include/db-4.1
1783DBMLIB=/usr/local/lib/db-4.1/libdb.a
1784.endd
168e428f 1785There is further detailed discussion about the various DBM libraries in the
9b371988 1786file &_doc/dbm.discuss.txt_& in the Exim distribution.
168e428f
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1787
1788
1789
f89d2485 1790.section "Pre-building configuration" "SECID25"
9b371988
PH
1791.cindex "building Exim" "pre-building configuration"
1792.cindex "configuration for building Exim"
1793.cindex "&_Local/Makefile_&"
1794.cindex "&_src/EDITME_&"
168e428f
PH
1795Before building Exim, a local configuration file that specifies options
1796independent of any operating system has to be created with the name
9b371988
PH
1797&_Local/Makefile_&. A template for this file is supplied as the file
1798&_src/EDITME_&, and it contains full descriptions of all the option settings
168e428f
PH
1799therein. These descriptions are therefore not repeated here. If you are
1800building Exim for the first time, the simplest thing to do is to copy
9b371988 1801&_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
168e428f
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1802
1803There are three settings that you must supply, because Exim will not build
1804without them. They are the location of the run time configuration file
1805(CONFIGURE_FILE), the directory in which Exim binaries will be installed
1806(BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1807maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1808a colon-separated list of file names; Exim uses the first of them that exists.
1809
1810There are a few other parameters that can be specified either at build time or
1811at run time, to enable the same binary to be used on a number of different
1812machines. However, if the locations of Exim's spool directory and log file
1813directory (if not within the spool directory) are fixed, it is recommended that
9b371988 1814you specify them in &_Local/Makefile_& instead of at run time, so that errors
168e428f
PH
1815detected early in Exim's execution (such as a malformed configuration file) can
1816be logged.
1817
9b371988 1818.cindex "content scanning" "specifying at build time"
068aaea8 1819Exim's interfaces for calling virus and spam scanning software directly from
168e428f
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1820access control lists are not compiled by default. If you want to include these
1821facilities, you need to set
9b371988
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1822.code
1823WITH_CONTENT_SCAN=yes
1824.endd
1825in your &_Local/Makefile_&. For details of the facilities themselves, see
1826chapter &<<CHAPexiscan>>&.
168e428f
PH
1827
1828
9b371988 1829.cindex "&_Local/eximon.conf_&"
3cb1b51e 1830.cindex "&_exim_monitor/EDITME_&"
168e428f 1831If you are going to build the Exim monitor, a similar configuration process is
9b371988
PH
1832required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1833your installation and saved under the name &_Local/eximon.conf_&. If you are
1834happy with the default settings described in &_exim_monitor/EDITME_&,
1835&_Local/eximon.conf_& can be empty, but it must exist.
168e428f
PH
1836
1837This is all the configuration that is needed in straightforward cases for known
1838operating systems. However, the building process is set up so that it is easy
1839to override options that are set by default or by operating-system-specific
1840configuration files, for example to change the name of the C compiler, which
9b371988
PH
1841defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1842do this.
168e428f
PH
1843
1844
1845
f89d2485 1846.section "Support for iconv()" "SECID26"
9b371988
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1847.cindex "&[iconv()]& support"
1848.cindex "RFC 2047"
168e428f
PH
1849The contents of header lines in messages may be encoded according to the rules
1850described RFC 2047. This makes it possible to transmit characters that are not
1851in the ASCII character set, and to label them as being in a particular
9b371988 1852character set. When Exim is inspecting header lines by means of the &%$h_%&
168e428f
PH
1853mechanism, it decodes them, and translates them into a specified character set
1854(default ISO-8859-1). The translation is possible only if the operating system
9b371988
PH
1855supports the &[iconv()]& function.
1856
1857However, some of the operating systems that supply &[iconv()]& do not support
1858very many conversions. The GNU &%libiconv%& library (available from
1859&url(http://www.gnu.org/software/libiconv/)) can be installed on such
1860systems to remedy this deficiency, as well as on systems that do not supply
1861&[iconv()]& at all. After installing &%libiconv%&, you should add
1862.code
1863HAVE_ICONV=yes
1864.endd
1865to your &_Local/Makefile_& and rebuild Exim.
1866
1867
1868
1869.section "Including TLS/SSL encryption support" "SECTinctlsssl"
1870.cindex "TLS" "including support for TLS"
1871.cindex "encryption" "including support for"
1872.cindex "SUPPORT_TLS"
1873.cindex "OpenSSL" "building Exim with"
1874.cindex "GnuTLS" "building Exim with"
168e428f
PH
1875Exim can be built to support encrypted SMTP connections, using the STARTTLS
1876command as per RFC 2487. It can also support legacy clients that expect to
1877start a TLS session immediately on connection to a non-standard port (see the
9b371988 1878&%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
168e428f
PH
1879line option).
1880
1881If you want to build Exim with TLS support, you must first install either the
1882OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1883implementing SSL.
1884
1885If OpenSSL is installed, you should set
9b371988
PH
1886.code
1887SUPPORT_TLS=yes
1888TLS_LIBS=-lssl -lcrypto
1889.endd
1890in &_Local/Makefile_&. You may also need to specify the locations of the
168e428f 1891OpenSSL library and include files. For example:
9b371988
PH
1892.code
1893SUPPORT_TLS=yes
1894TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1895TLS_INCLUDE=-I/usr/local/openssl/include/
1896.endd
7e6a8985
PP
1897.cindex "pkg-config" "OpenSSL"
1898If you have &'pkg-config'& available, then instead you can just use:
1899.code
1900SUPPORT_TLS=yes
1901USE_OPENSSL_PC=openssl
1902.endd
9b371988 1903.cindex "USE_GNUTLS"
168e428f 1904If GnuTLS is installed, you should set
9b371988
PH
1905.code
1906SUPPORT_TLS=yes
1907USE_GNUTLS=yes
1908TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1909.endd
1910in &_Local/Makefile_&, and again you may need to specify the locations of the
168e428f 1911library and include files. For example:
9b371988
PH
1912.code
1913SUPPORT_TLS=yes
1914USE_GNUTLS=yes
1915TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1916TLS_INCLUDE=-I/usr/gnu/include
1917.endd
7e6a8985
PP
1918.cindex "pkg-config" "GnuTLS"
1919If you have &'pkg-config'& available, then instead you can just use:
1920.code
1921SUPPORT_TLS=yes
1922USE_GNUTLS=yes
1923USE_GNUTLS_PC=gnutls
1924.endd
7e6a8985 1925
168e428f 1926You do not need to set TLS_INCLUDE if the relevant directory is already
9b371988
PH
1927specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1928given in chapter &<<CHAPTLS>>&.
168e428f
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1929
1930
1931
1932
b52ed2b3
NM
1933.section "Use of tcpwrappers" "SECID27"
1934
f89d2485 1935.cindex "tcpwrappers, building Exim to support"
9b371988 1936.cindex "USE_TCP_WRAPPERS"
5dc43717
JJ
1937.cindex "TCP_WRAPPERS_DAEMON_NAME"
1938.cindex "tcp_wrappers_daemon_name"
9b371988
PH
1939Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1940SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
168e428f 1941alternative to Exim's own checking facilities for installations that are
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1942already making use of &'tcpwrappers'& for other purposes. To do this, you
1943should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1944&_tcpd.h_& to be available at compile time, and also ensure that the library
1945&_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1946EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1947you might have
1948.code
1949USE_TCP_WRAPPERS=yes
1950CFLAGS=-O -I/usr/local/include
1951EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1952.endd
5dc43717
JJ
1953in &_Local/Makefile_&. The daemon name to use in the &'tcpwrappers'& control
1954files is &"exim"&. For example, the line
9b371988
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1955.code
1956exim : LOCAL 192.168.1. .friendly.domain.example
1957.endd
1958in your &_/etc/hosts.allow_& file allows connections from the local host, from
1959the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&.
5dc43717
JJ
1960All other connections are denied. The daemon name used by &'tcpwrappers'&
1961can be changed at build time by setting TCP_WRAPPERS_DAEMON_NAME in
a543079f 1962&_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the
5dc43717 1963configure file. Consult the &'tcpwrappers'& documentation for
168e428f 1964further details.
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1965
1966
f89d2485 1967.section "Including support for IPv6" "SECID28"
9b371988 1968.cindex "IPv6" "including support for"
168e428f 1969Exim contains code for use on systems that have IPv6 support. Setting
9b371988 1970&`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
168e428f
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1971it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1972where the IPv6 support is not fully integrated into the normal include and
1973library files.
1974
1975Two different types of DNS record for handling IPv6 addresses have been
f89d2485 1976defined. AAAA records (analogous to A records for IPv4) are in use, and are
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1977currently seen as the mainstream. Another record type called A6 was proposed
1978as better than AAAA because it had more flexibility. However, it was felt to be
9b371988 1979over-complex, and its status was reduced to &"experimental"&. It is not known
168e428f 1980if anyone is actually using A6 records. Exim has support for A6 records, but
9b371988 1981this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
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1982support has not been tested for some time.
1983
1984
1985
0a349494
PP
1986.section "Dynamically loaded lookup module support" "SECTdynamicmodules"
1987.cindex "lookup modules"
1988.cindex "dynamic modules"
1989.cindex ".so building"
1990On some platforms, Exim supports not compiling all lookup types directly into
1991the main binary, instead putting some into external modules which can be loaded
1992on demand.
1993This permits packagers to build Exim with support for lookups with extensive
1994library dependencies without requiring all users to install all of those
1995dependencies.
1996Most, but not all, lookup types can be built this way.
1997
1998Set &`LOOKUP_MODULE_DIR`& to the directory into which the modules will be
1999installed; Exim will only load modules from that directory, as a security
2000measure. You will need to set &`CFLAGS_DYNAMIC`& if not already defined
2001for your OS; see &_OS/Makefile-Linux_& for an example.
2002Some other requirements for adjusting &`EXTRALIBS`& may also be necessary,
2003see &_src/EDITME_& for details.
2004
2005Then, for each module to be loaded dynamically, define the relevant
2006&`LOOKUP_`&<&'lookup_type'&> flags to have the value "2" instead of "yes".
2007For example, this will build in lsearch but load sqlite and mysql support
2008on demand:
2009.code
2010LOOKUP_LSEARCH=yes
2011LOOKUP_SQLITE=2
2012LOOKUP_MYSQL=2
2013.endd
5d758a46 2014
0a349494 2015
f89d2485 2016.section "The building process" "SECID29"
9b371988
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2017.cindex "build directory"
2018Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
2019created, run &'make'& at the top level. It determines the architecture and
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2020operating system types, and creates a build directory if one does not exist.
2021For example, on a Sun system running Solaris 8, the directory
9b371988
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2022&_build-SunOS5-5.8-sparc_& is created.
2023.cindex "symbolic link" "to source files"
168e428f
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2024Symbolic links to relevant source files are installed in the build directory.
2025
9b371988 2026&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
168e428f
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2027building process fails if it is set.
2028
9b371988 2029If this is the first time &'make'& has been run, it calls a script that builds
168e428f 2030a make file inside the build directory, using the configuration files from the
9b371988
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2031&_Local_& directory. The new make file is then passed to another instance of
2032&'make'&. This does the real work, building a number of utility scripts, and
168e428f 2033then compiling and linking the binaries for the Exim monitor (if configured), a
9b371988
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2034number of utility programs, and finally Exim itself. The command &`make
2035makefile`& can be used to force a rebuild of the make file in the build
168e428f
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2036directory, should this ever be necessary.
2037
2038If you have problems building Exim, check for any comments there may be in the
9b371988 2039&_README_& file concerning your operating system, and also take a look at the
168e428f
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2040FAQ, where some common problems are covered.
2041
2042
2043
f89d2485 2044.section 'Output from &"make"&' "SECID283"
9b371988 2045The output produced by the &'make'& process for compile lines is often very
068aaea8
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2046unreadable, because these lines can be very long. For this reason, the normal
2047output is suppressed by default, and instead output similar to that which
2048appears when compiling the 2.6 Linux kernel is generated: just a short line for
2049each module that is being compiled or linked. However, it is still possible to
9b371988
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2050get the full output, by calling &'make'& like this:
2051.code
2052FULLECHO='' make -e
2053.endd
2054The value of FULLECHO defaults to &"@"&, the flag character that suppresses
2055command reflection in &'make'&. When you ask for the full output, it is
3cb1b51e 2056given in addition to the short output.
068aaea8
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2057
2058
2059
9b371988 2060.section "Overriding build-time options for Exim" "SECToverride"
f89d2485 2061.cindex "build-time options, overriding"
168e428f
PH
2062The main make file that is created at the beginning of the building process
2063consists of the concatenation of a number of files which set configuration
9b371988 2064values, followed by a fixed set of &'make'& instructions. If a value is set
168e428f
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2065more than once, the last setting overrides any previous ones. This provides a
2066convenient way of overriding defaults. The files that are concatenated are, in
2067order:
9b371988
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2068.display
2069&_OS/Makefile-Default_&
2070&_OS/Makefile-_&<&'ostype'&>
2071&_Local/Makefile_&
2072&_Local/Makefile-_&<&'ostype'&>
2073&_Local/Makefile-_&<&'archtype'&>
2074&_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
2075&_OS/Makefile-Base_&
2076.endd
2077.cindex "&_Local/Makefile_&"
2078.cindex "building Exim" "operating system type"
2079.cindex "building Exim" "architecture type"
2080where <&'ostype'&> is the operating system type and <&'archtype'&> is the
2081architecture type. &_Local/Makefile_& is required to exist, and the building
2082process fails if it is absent. The other three &_Local_& files are optional,
168e428f
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2083and are often not needed.
2084
9b371988
PH
2085The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
2086called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
168e428f
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2087the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
2088values are used, thereby providing a means of forcing particular settings.
9b371988 2089Otherwise, the scripts try to get values from the &%uname%& command. If this
168e428f 2090fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
9b371988 2091of &'ad hoc'& transformations are then applied, to produce the standard names
168e428f
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2092that Exim expects. You can run these scripts directly from the shell in order
2093to find out what values are being used on your system.
2094
2095
9b371988 2096&_OS/Makefile-Default_& contains comments about the variables that are set
168e428f
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2097therein. Some (but not all) are mentioned below. If there is something that
2098needs changing, review the contents of this file and the contents of the make
9b371988 2099file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
168e428f
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2100default values are.
2101
2102
9b371988
PH
2103.cindex "building Exim" "overriding default settings"
2104If you need to change any of the values that are set in &_OS/Makefile-Default_&
2105or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
168e428f 2106need to change the original files. Instead, you should make the changes by
9b371988
PH
2107putting the new values in an appropriate &_Local_& file. For example,
2108.cindex "Tru64-Unix build-time settings"
168e428f
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2109when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2110formerly DEC-OSF1) operating system, it is necessary to specify that the C
9b371988
PH
2111compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2112called with the option &%-std1%&, to make it recognize some of the features of
168e428f 2113Standard C that Exim uses. (Most other compilers recognize Standard C by
9b371988 2114default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
168e428f 2115containing the lines
9b371988
PH
2116.code
2117CC=cc
2118CFLAGS=-std1
2119.endd
168e428f 2120If you are compiling for just one operating system, it may be easier to put
9b371988 2121these lines directly into &_Local/Makefile_&.
168e428f
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2122
2123Keeping all your local configuration settings separate from the distributed
2124files makes it easy to transfer them to new versions of Exim simply by copying
9b371988 2125the contents of the &_Local_& directory.
168e428f
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2126
2127
9b371988
PH
2128.cindex "NIS lookup type" "including support for"
2129.cindex "NIS+ lookup type" "including support for"
2130.cindex "LDAP" "including support for"
2131.cindex "lookup" "inclusion in binary"
168e428f
PH
2132Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2133lookup, but not all systems have these components installed, so the default is
2134not to include the relevant code in the binary. All the different kinds of file
2135and database lookup that Exim supports are implemented as separate code modules
2136which are included only if the relevant compile-time options are set. In the
9b371988
PH
2137case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2138.code
2139LOOKUP_LDAP=yes
2140LOOKUP_NIS=yes
2141LOOKUP_NISPLUS=yes
2142.endd
168e428f 2143and similar settings apply to the other lookup types. They are all listed in
9b371988 2144&_src/EDITME_&. In many cases the relevant include files and interface
168e428f 2145libraries need to be installed before compiling Exim.
9b371988 2146.cindex "cdb" "including support for"
068aaea8
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2147However, there are some optional lookup types (such as cdb) for which
2148the code is entirely contained within Exim, and no external include
168e428f
PH
2149files or libraries are required. When a lookup type is not included in the
2150binary, attempts to configure Exim to use it cause run time configuration
2151errors.
2152
7e6a8985
PP
2153.cindex "pkg-config" "lookups"
2154.cindex "pkg-config" "authenticators"
252e0c7b
PP
2155Many systems now use a tool called &'pkg-config'& to encapsulate information
2156about how to compile against a library; Exim has some initial support for
2157being able to use pkg-config for lookups and authenticators. For any given
2158makefile variable which starts &`LOOKUP_`& or &`AUTH_`&, you can add a new
2159variable with the &`_PC`& suffix in the name and assign as the value the
2160name of the package to be queried. The results of querying via the
2161&'pkg-config'& command will be added to the appropriate Makefile variables
2162with &`+=`& directives, so your version of &'make'& will need to support that
2163syntax. For instance:
2164.code
2165LOOKUP_SQLITE=yes
2166LOOKUP_SQLITE_PC=sqlite3
2167AUTH_GSASL=yes
2168AUTH_GSASL_PC=libgsasl
2169AUTH_HEIMDAL_GSSAPI=yes
2170AUTH_HEIMDAL_GSSAPI_PC=heimdal-gssapi
2171.endd
252e0c7b 2172
9b371988 2173.cindex "Perl" "including support for"
168e428f
PH
2174Exim can be linked with an embedded Perl interpreter, allowing Perl
2175subroutines to be called during string expansion. To enable this facility,
9b371988
PH
2176.code
2177EXIM_PERL=perl.o
2178.endd
2179must be defined in &_Local/Makefile_&. Details of this facility are given in
2180chapter &<<CHAPperl>>&.
168e428f 2181
f89d2485 2182.cindex "X11 libraries, location of"
168e428f 2183The location of the X11 libraries is something that varies a lot between
068aaea8 2184operating systems, and there may be different versions of X11 to cope
168e428f
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2185with. Exim itself makes no use of X11, but if you are compiling the Exim
2186monitor, the X11 libraries must be available.
9b371988
PH
2187The following three variables are set in &_OS/Makefile-Default_&:
2188.code
2189X11=/usr/X11R6
2190XINCLUDE=-I$(X11)/include
2191XLFLAGS=-L$(X11)/lib
2192.endd
168e428f 2193These are overridden in some of the operating-system configuration files. For
9b371988
PH
2194example, in &_OS/Makefile-SunOS5_& there is
2195.code
2196X11=/usr/openwin
2197XINCLUDE=-I$(X11)/include
2198XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2199.endd
168e428f
PH
2200If you need to override the default setting for your operating system, place a
2201definition of all three of these variables into your
9b371988 2202&_Local/Makefile-<ostype>_& file.
168e428f 2203
9b371988 2204.cindex "EXTRALIBS"
168e428f
PH
2205If you need to add any extra libraries to the link steps, these can be put in a
2206variable called EXTRALIBS, which appears in all the link commands, but by
2207default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2208command for linking the main Exim binary, and not for any associated utilities.
2209
9b371988 2210.cindex "DBM libraries" "configuration for building"
168e428f 2211There is also DBMLIB, which appears in the link commands for binaries that
9b371988 2212use DBM functions (see also section &<<SECTdb>>&). Finally, there is
168e428f
PH
2213EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2214binary, and which can be used, for example, to include additional X11
2215libraries.
2216
9b371988 2217.cindex "configuration file" "editing"
168e428f
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2218The make file copes with rebuilding Exim correctly if any of the configuration
2219files are edited. However, if an optional configuration file is deleted, it is
9b371988
PH
2220necessary to touch the associated non-optional file (that is,
2221&_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
168e428f
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2222
2223
f89d2485 2224.section "OS-specific header files" "SECID30"
9b371988
PH
2225.cindex "&_os.h_&"
2226.cindex "building Exim" "OS-specific C header files"
2227The &_OS_& directory contains a number of files with names of the form
2228&_os.h-<ostype>_&. These are system-specific C header files that should not
168e428f 2229normally need to be changed. There is a list of macro settings that are
9b371988 2230recognized in the file &_OS/os.configuring_&, which should be consulted if you
168e428f
PH
2231are porting Exim to a new operating system.
2232
2233
2234
f89d2485
PH
2235.section "Overriding build-time options for the monitor" "SECID31"
2236.cindex "building Eximon"
168e428f
PH
2237A similar process is used for overriding things when building the Exim monitor,
2238where the files that are involved are
9b371988
PH
2239.display
2240&_OS/eximon.conf-Default_&
2241&_OS/eximon.conf-_&<&'ostype'&>
2242&_Local/eximon.conf_&
2243&_Local/eximon.conf-_&<&'ostype'&>
2244&_Local/eximon.conf-_&<&'archtype'&>
2245&_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2246.endd
2247.cindex "&_Local/eximon.conf_&"
168e428f 2248As with Exim itself, the final three files need not exist, and in this case the
9b371988
PH
2249&_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2250&_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
168e428f
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2251variables of the same name, preceded by EXIMON_. For example, setting
2252EXIMON_LOG_DEPTH in the environment overrides the value of
2253LOG_DEPTH at run time.
4f578862 2254.ecindex IIDbuex
168e428f
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2255
2256
f89d2485 2257.section "Installing Exim binaries and scripts" "SECID32"
9b371988
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2258.cindex "installing Exim"
2259.cindex "BIN_DIRECTORY"
2260The command &`make install`& runs the &(exim_install)& script with no
2261arguments. The script copies binaries and utility scripts into the directory
2262whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2263.cindex "setuid" "installing Exim with"
068aaea8
PH
2264The install script copies files only if they are newer than the files they are
2265going to replace. The Exim binary is required to be owned by root and have the
9b371988
PH
2266&'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2267install`& as root so that it can set up the Exim binary in this way. However, in
068aaea8
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2268some special situations (for example, if a host is doing no local deliveries)
2269it may be possible to run Exim without making the binary setuid root (see
9b371988 2270chapter &<<CHAPsecurity>>& for details).
168e428f 2271
9b371988 2272.cindex "CONFIGURE_FILE"
168e428f 2273Exim's run time configuration file is named by the CONFIGURE_FILE setting
9b371988
PH
2274in &_Local/Makefile_&. If this names a single file, and the file does not
2275exist, the default configuration file &_src/configure.default_& is copied there
168e428f
PH
2276by the installation script. If a run time configuration file already exists, it
2277is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2278alternative files, no default is installed.
2279
9b371988
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2280.cindex "system aliases file"
2281.cindex "&_/etc/aliases_&"
168e428f
PH
2282One change is made to the default configuration file when it is installed: the
2283default configuration contains a router that references a system aliases file.
2284The path to this file is set to the value specified by
9b371988 2285SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
168e428f
PH
2286If the system aliases file does not exist, the installation script creates it,
2287and outputs a comment to the user.
2288
2289The created file contains no aliases, but it does contain comments about the
2290aliases a site should normally have. Mail aliases have traditionally been
9b371988
PH
2291kept in &_/etc/aliases_&. However, some operating systems are now using
2292&_/etc/mail/aliases_&. You should check if yours is one of these, and change
168e428f
PH
2293Exim's configuration if necessary.
2294
2295The default configuration uses the local host's name as the only local domain,
9b371988
PH
2296and is set up to do local deliveries into the shared directory &_/var/mail_&,
2297running as the local user. System aliases and &_.forward_& files in users' home
168e428f
PH
2298directories are supported, but no NIS or NIS+ support is configured. Domains
2299other than the name of the local host are routed using the DNS, with delivery
2300over SMTP.
2301
168e428f
PH
2302It is possible to install Exim for special purposes (such as building a binary
2303distribution) in a private part of the file system. You can do this by a
2304command such as
9b371988
PH
2305.code
2306make DESTDIR=/some/directory/ install
2307.endd
168e428f
PH
2308This has the effect of pre-pending the specified directory to all the file
2309paths, except the name of the system aliases file that appears in the default
9b371988 2310configuration. (If a default alias file is created, its name &'is'& modified.)
168e428f
PH
2311For backwards compatibility, ROOT is used if DESTDIR is not set,
2312but this usage is deprecated.
2313
9b371988
PH
2314.cindex "installing Exim" "what is not installed"
2315Running &'make install'& does not copy the Exim 4 conversion script
40df1be3
TF
2316&'convert4r4'&. You will probably run this only once if you are
2317upgrading from Exim 3. None of the documentation files in the &_doc_&
168e428f 2318directory are copied, except for the info files when you have set
9b371988 2319INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
168e428f 2320
9b371988 2321For the utility programs, old versions are renamed by adding the suffix &_.O_&
168e428f
PH
2322to their names. The Exim binary itself, however, is handled differently. It is
2323installed under a name that includes the version number and the compile number,
2aee48d6 2324for example &_exim-&version()-1_&. The script then arranges for a symbolic link
9b371988
PH
2325called &_exim_& to point to the binary. If you are updating a previous version
2326of Exim, the script takes care to ensure that the name &_exim_& is never absent
168e428f
PH
2327from the directory (as seen by other processes).
2328
9b371988
PH
2329.cindex "installing Exim" "testing the script"
2330If you want to see what the &'make install'& will do before running it for
2331real, you can pass the &%-n%& option to the installation script by this
2332command:
2333.code
2334make INSTALL_ARG=-n install
2335.endd
168e428f
PH
2336The contents of the variable INSTALL_ARG are passed to the installation
2337script. You do not need to be root to run this test. Alternatively, you can run
2338the installation script directly, but this must be from within the build
2339directory. For example, from the top-level Exim directory you could use this
2340command:
9b371988
PH
2341.code
2342(cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2343.endd
2344.cindex "installing Exim" "install script options"
168e428f
PH
2345There are two other options that can be supplied to the installation script.
2346
9b371988
PH
2347.ilist
2348&%-no_chown%& bypasses the call to change the owner of the installed binary
168e428f 2349to root, and the call to make it a setuid binary.
9b371988
PH
2350.next
2351&%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
168e428f 2352installed binary.
9b371988 2353.endlist
168e428f
PH
2354
2355INSTALL_ARG can be used to pass these options to the script. For example:
9b371988
PH
2356.code
2357make INSTALL_ARG=-no_symlink install
2358.endd
168e428f
PH
2359The installation script can also be given arguments specifying which files are
2360to be copied. For example, to install just the Exim binary, and nothing else,
2361without creating the symbolic link, you could use:
9b371988
PH
2362.code
2363make INSTALL_ARG='-no_symlink exim' install
2364.endd
168e428f
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2365
2366
2367
9b371988
PH
2368.section "Installing info documentation" "SECTinsinfdoc"
2369.cindex "installing Exim" "&'info'& documentation"
2370Not all systems use the GNU &'info'& system for documentation, and for this
168e428f
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2371reason, the Texinfo source of Exim's documentation is not included in the main
2372distribution. Instead it is available separately from the ftp site (see section
9b371988 2373&<<SECTavail>>&).
168e428f 2374
9b371988
PH
2375If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2376source of the documentation is found in the source tree, running &`make
2377install`& automatically builds the info files and installs them.
168e428f
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2378
2379
2380
f89d2485 2381.section "Setting up the spool directory" "SECID33"
9b371988 2382.cindex "spool directory" "creating"
168e428f
PH
2383When it starts up, Exim tries to create its spool directory if it does not
2384exist. The Exim uid and gid are used for the owner and group of the spool
2385directory. Sub-directories are automatically created in the spool directory as
2386necessary.
2387
2388
2389
2390
f89d2485 2391.section "Testing" "SECID34"
9b371988 2392.cindex "testing" "installation"
168e428f
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2393Having installed Exim, you can check that the run time configuration file is
2394syntactically valid by running the following command, which assumes that the
2395Exim binary directory is within your PATH environment variable:
9b371988
PH
2396.code
2397exim -bV
2398.endd
168e428f
PH
2399If there are any errors in the configuration file, Exim outputs error messages.
2400Otherwise it outputs the version number and build date,
2401the DBM library that is being used, and information about which drivers and
2402other optional code modules are included in the binary.
2403Some simple routing tests can be done by using the address testing option. For
2404example,
9b371988
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2405.display
2406&`exim -bt`& <&'local username'&>
2407.endd
168e428f 2408should verify that it recognizes a local mailbox, and
9b371988
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2409.display
2410&`exim -bt`& <&'remote address'&>
2411.endd
168e428f
PH
2412a remote one. Then try getting it to deliver mail, both locally and remotely.
2413This can be done by passing messages directly to Exim, without going through a
2414user agent. For example:
9b371988 2415.code
068aaea8
PH
2416exim -v postmaster@your.domain.example
2417From: user@your.domain.example
2418To: postmaster@your.domain.example
2419Subject: Testing Exim
168e428f 2420
068aaea8
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2421This is a test message.
2422^D
9b371988
PH
2423.endd
2424The &%-v%& option causes Exim to output some verification of what it is doing.
168e428f 2425In this case you should see copies of three log lines, one for the message's
9b371988 2426arrival, one for its delivery, and one containing &"Completed"&.
168e428f 2427
9b371988
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2428.cindex "delivery" "problems with"
2429If you encounter problems, look at Exim's log files (&'mainlog'& and
2430&'paniclog'&) to see if there is any relevant information there. Another source
168e428f 2431of information is running Exim with debugging turned on, by specifying the
9b371988 2432&%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
168e428f 2433with debugging turned on by a command of the form
9b371988
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2434.display
2435&`exim -d -M`& <&'exim-message-id'&>
2436.endd
2437You must be root or an &"admin user"& in order to do this. The &%-d%& option
168e428f 2438produces rather a lot of output, but you can cut this down to specific areas.
9b371988
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2439For example, if you use &%-d-all+route%& only the debugging information
2440relevant to routing is included. (See the &%-d%& option in chapter
2441&<<CHAPcommandline>>& for more details.)
168e428f 2442
9b371988
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2443.cindex '&"sticky"& bit'
2444.cindex "lock files"
168e428f
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2445One specific problem that has shown up on some sites is the inability to do
2446local deliveries into a shared mailbox directory, because it does not have the
9b371988 2447&"sticky bit"& set on it. By default, Exim tries to create a lock file before
168e428f 2448writing to a mailbox file, and if it cannot create the lock file, the delivery
9b371988 2449is deferred. You can get round this either by setting the &"sticky bit"& on the
168e428f
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2450directory, or by setting a specific group for local deliveries and allowing
2451that group to create files in the directory (see the comments above the
9b371988 2452&(local_delivery)& transport in the default configuration file). Another
168e428f 2453approach is to configure Exim not to use lock files, but just to rely on
9b371988
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2454&[fcntl()]& locking instead. However, you should do this only if all user
2455agents also use &[fcntl()]& locking. For further discussion of locking issues,
2456see chapter &<<CHAPappendfile>>&.
168e428f
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2457
2458One thing that cannot be tested on a system that is already running an MTA is
2459the receipt of incoming SMTP mail on the standard SMTP port. However, the
9b371988
PH
2460&%-oX%& option can be used to run an Exim daemon that listens on some other
2461port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2462&'exim_checkaccess'& utility can be used to check out policy controls on
168e428f
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2463incoming SMTP mail.
2464
2465Testing a new version on a system that is already running Exim can most easily
2466be done by building a binary with a different CONFIGURE_FILE setting. From
2467within the run time configuration, all other file and directory names
2468that Exim uses can be altered, in order to keep it entirely clear of the
2469production version.
2470
2471
f89d2485 2472.section "Replacing another MTA with Exim" "SECID35"
9b371988 2473.cindex "replacing another MTA"
168e428f
PH
2474Building and installing Exim for the first time does not of itself put it in
2475general use. The name by which the system's MTA is called by mail user agents
9b371988
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2476is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2477operating system), and it is necessary to make this name point to the &'exim'&
168e428f 2478binary in order to get the user agents to pass messages to Exim. This is
9b371988
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2479normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2480or &_/usr/lib/sendmail_&
2481.cindex "symbolic link" "to &'exim'& binary"
2482a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
168e428f
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2483privilege and executable status from the old MTA. It is then necessary to stop
2484and restart the mailer daemon, if one is running.
2485
f89d2485 2486.cindex "FreeBSD, MTA indirection"
9b371988 2487.cindex "&_/etc/mail/mailer.conf_&"
168e428f
PH
2488Some operating systems have introduced alternative ways of switching MTAs. For
2489example, if you are running FreeBSD, you need to edit the file
9b371988 2490&_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
168e428f
PH
2491described. A typical example of the contents of this file for running Exim is
2492as follows:
9b371988
PH
2493.code
2494sendmail /usr/exim/bin/exim
2495send-mail /usr/exim/bin/exim
2496mailq /usr/exim/bin/exim -bp
2497newaliases /usr/bin/true
2498.endd
2499Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2500your Exim installation is &"live"&. Check it by sending a message from your
168e428f
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2501favourite user agent.
2502
2503You should consider what to tell your users about the change of MTA. Exim may
2504have different capabilities to what was previously running, and there are
2505various operational differences such as the text of messages produced by
2506command line options and in bounce messages. If you allow your users to make
2507use of Exim's filtering capabilities, you should make the document entitled
9b371988 2508&'Exim's interface to mail filtering'& available to them.
168e428f
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2509
2510
2511
f89d2485 2512.section "Upgrading Exim" "SECID36"
9b371988 2513.cindex "upgrading Exim"
168e428f
PH
2514If you are already running Exim on your host, building and installing a new
2515version automatically makes it available to MUAs, or any other programs that
2516call the MTA directly. However, if you are running an Exim daemon, you do need
9b371988
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2517to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2518new binary. You do not need to stop processing mail in order to install a new
068aaea8
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2519version of Exim. The install script does not modify an existing runtime
2520configuration file.
2521
168e428f
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2522
2523
2524
f89d2485 2525.section "Stopping the Exim daemon on Solaris" "SECID37"
9b371988 2526.cindex "Solaris" "stopping Exim on"
168e428f 2527The standard command for stopping the mailer daemon on Solaris is
9b371988
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2528.code
2529/etc/init.d/sendmail stop
2530.endd
2531If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2532fails to stop Exim because it uses the command &'ps -e'& and greps the output
2533for the text &"sendmail"&; this is not present because the actual program name
2534(that is, &"exim"&) is given by the &'ps'& command with these options. A
2535solution is to replace the line that finds the process id with something like
2536.code
2537pid=`cat /var/spool/exim/exim-daemon.pid`
2538.endd
168e428f
PH
2539to obtain the daemon's pid directly from the file that Exim saves it in.
2540
9b371988 2541Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
168e428f
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2542still be received from local processes, and if automatic delivery is configured
2543(the normal case), deliveries will still occur.
2544
2545
2546
2547
9b371988
PH
2548. ////////////////////////////////////////////////////////////////////////////
2549. ////////////////////////////////////////////////////////////////////////////
168e428f 2550
9b371988 2551.chapter "The Exim command line" "CHAPcommandline"
4f578862
PH
2552.scindex IIDclo1 "command line" "options"
2553.scindex IIDclo2 "options" "command line"
168e428f
PH
2554Exim's command line takes the standard Unix form of a sequence of options,
2555each starting with a hyphen character, followed by a number of arguments. The
2556options are compatible with the main options of Sendmail, and there are also
2557some additional options, some of which are compatible with Smail 3. Certain
2558combinations of options do not make sense, and provoke an error if used.
2559The form of the arguments depends on which options are set.
2560
2561
f89d2485 2562.section "Setting options by program name" "SECID38"
9b371988
PH
2563.cindex "&'mailq'&"
2564If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
168e428f 2565were present before any other options.
9b371988 2566The &%-bp%& option requests a listing of the contents of the mail queue on the
168e428f
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2567standard output.
2568This feature is for compatibility with some systems that contain a command of
2569that name in one of the standard libraries, symbolically linked to
9b371988
PH
2570&_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2571
2572.cindex "&'rsmtp'&"
2573If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2574were present before any other options, for compatibility with Smail. The
2575&%-bS%& option is used for reading in a number of messages in batched SMTP
2576format.
2577
2578.cindex "&'rmail'&"
2579If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2580&%-oee%& options were present before any other options, for compatibility with
2581Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2582
2583.cindex "&'runq'&"
2584.cindex "queue runner"
2585If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2586were present before any other options, for compatibility with Smail. The &%-q%&
168e428f
PH
2587option causes a single queue runner process to be started.
2588
9b371988
PH
2589.cindex "&'newaliases'&"
2590.cindex "alias file" "building"
2591.cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2592If Exim is called under the name &'newaliases'& it behaves as if the option
2593&%-bi%& were present before any other options, for compatibility with Sendmail.
168e428f
PH
2594This option is used for rebuilding Sendmail's alias file. Exim does not have
2595the concept of a single alias file, but can be configured to run a given
9b371988 2596command if called with the &%-bi%& option.
168e428f
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2597
2598
9b371988
PH
2599.section "Trusted and admin users" "SECTtrustedadmin"
2600Some Exim options are available only to &'trusted users'& and others are
2601available only to &'admin users'&. In the description below, the phrases &"Exim
2602user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2603EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2604&%exim_group%& options. These do not necessarily have to use the name &"exim"&.
168e428f 2605
9b371988 2606.ilist
f89d2485 2607.cindex "trusted users" "definition of"
9b371988 2608.cindex "user" "trusted definition of"
168e428f 2609The trusted users are root, the Exim user, any user listed in the
9b371988
PH
2610&%trusted_users%& configuration option, and any user whose current group or any
2611supplementary group is one of those listed in the &%trusted_groups%&
168e428f 2612configuration option. Note that the Exim group is not automatically trusted.
9b371988
PH
2613
2614.cindex '&"From"& line'
2615.cindex "envelope sender"
2616Trusted users are always permitted to use the &%-f%& option or a leading
2617&"From&~"& line to specify the envelope sender of a message that is passed to
2618Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2619See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2620users to set envelope senders.
2621
2622.cindex "&'From:'& header line"
2623.cindex "&'Sender:'& header line"
2624For a trusted user, there is never any check on the contents of the &'From:'&
2625header line, and a &'Sender:'& line is never added. Furthermore, any existing
2626&'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2627
168e428f
PH
2628Trusted users may also specify a host name, host address, interface address,
2629protocol name, ident value, and authentication data when submitting a message
2630locally. Thus, they are able to insert messages into Exim's queue locally that
2631have the characteristics of messages received from a remote host. Untrusted
9b371988 2632users may in some circumstances use &%-f%&, but can never set the other values
168e428f 2633that are available to trusted users.
9b371988
PH
2634.next
2635.cindex "user" "admin definition of"
2636.cindex "admin user" "definition of"
168e428f 2637The admin users are root, the Exim user, and any user that is a member of the
9b371988 2638Exim group or of any group listed in the &%admin_groups%& configuration option.
168e428f 2639The current group does not have to be one of these groups.
9b371988 2640
168e428f
PH
2641Admin users are permitted to list the queue, and to carry out certain
2642operations on messages, for example, to force delivery failures. It is also
2643necessary to be an admin user in order to see the full information provided by
2644the Exim monitor, and full debugging output.
9b371988
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2645
2646By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2647Exim to attempt delivery of messages on its queue is restricted to admin users.
2648However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2649option false (that is, specifying &%no_prod_requires_admin%&).
2650
2651Similarly, the use of the &%-bp%& option to list all the messages in the queue
2652is restricted to admin users unless &%queue_list_requires_admin%& is set
168e428f 2653false.
9b371988 2654.endlist
168e428f
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2655
2656
9b371988 2657&*Warning*&: If you configure your system so that admin users are able to
168e428f
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2658edit Exim's configuration file, you are giving those users an easy way of
2659getting root. There is further discussion of this issue at the start of chapter
9b371988 2660&<<CHAPconf>>&.
168e428f
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2661
2662
2663
2664
f89d2485 2665.section "Command line options" "SECID39"
db9452a9
PH
2666Exim's command line options are described in alphabetical order below. If none
2667of the options that specifies a specific action (such as starting the daemon or
2668a queue runner, or testing an address, or receiving a message in a specific
2669format, or listing the queue) are present, and there is at least one argument
2670on the command line, &%-bm%& (accept a local message on the standard input,
2671with the arguments specifying the recipients) is assumed. Otherwise, Exim
2672outputs a brief message about itself and exits.
168e428f 2673
9b371988
PH
2674. ////////////////////////////////////////////////////////////////////////////
2675. Insert a stylized XML comment here, to identify the start of the command line
2676. options. This is for the benefit of the Perl script that automatically
2677. creates a man page for the options.
2678. ////////////////////////////////////////////////////////////////////////////
168e428f 2679
9b371988 2680.literal xml
168e428f 2681<!-- === Start of command line options === -->
9b371988 2682.literal off
168e428f
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2683
2684
9b371988
PH
2685.vlist
2686.vitem &%--%&
2687.oindex "--"
2688.cindex "options" "command line; terminating"
168e428f
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2689This is a pseudo-option whose only purpose is to terminate the options and
2690therefore to cause subsequent command line items to be treated as arguments
2691rather than options, even if they begin with hyphens.
2692
9b371988
PH
2693.vitem &%--help%&
2694.oindex "&%--help%&"
168e428f
PH
2695This option causes Exim to output a few sentences stating what it is.
2696The same output is generated if the Exim binary is called with no options and
2697no arguments.
2698
4b2241d2
PP
2699.vitem &%--version%&
2700.oindex "&%--version%&"
2701This option is an alias for &%-bV%& and causes version information to be
2702displayed.
2703
a3fb9793
PP
2704.new
2705.vitem &%-Ac%& &&&
2706 &%-Am%&
2707.oindex "&%-Ac%&"
2708.oindex "&%-Am%&"
2709These options are used by Sendmail for selecting configuration files and are
2710ignored by Exim.
2711.wen
2712
9b371988
PH
2713.vitem &%-B%&<&'type'&>
2714.oindex "&%-B%&"
2715.cindex "8-bit characters"
2716.cindex "Sendmail compatibility" "8-bit characters"
168e428f
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2717This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2718clean; it ignores this option.
2719
9b371988
PH
2720.vitem &%-bd%&
2721.oindex "&%-bd%&"
2722.cindex "daemon"
f89d2485 2723.cindex "SMTP" "listener"
9b371988 2724.cindex "queue runner"
168e428f 2725This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
9b371988
PH
2726the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2727that the daemon should also initiate periodic queue runs.
2728
2729The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2730(debugging) or &%-v%& (verifying) options are set, the daemon does not
168e428f
PH
2731disconnect from the controlling terminal. When running this way, it can be
2732stopped by pressing ctrl-C.
9b371988 2733
168e428f
PH
2734By default, Exim listens for incoming connections to the standard SMTP port on
2735all the host's running interfaces. However, it is possible to listen on other
2736ports, on multiple ports, and only on specific interfaces. Chapter
9b371988
PH
2737&<<CHAPinterfaces>>& contains a description of the options that control this.
2738
168e428f 2739When a listening daemon
9b371988
PH
2740.cindex "daemon" "process id (pid)"
2741.cindex "pid (process id)" "of daemon"
2742is started without the use of &%-oX%& (that is, without overriding the normal
2743configuration), it writes its process id to a file called &_exim-daemon.pid_&
2744in Exim's spool directory. This location can be overridden by setting
2745PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
168e428f 2746running as root.
9b371988
PH
2747
2748When &%-oX%& is used on the command line to start a listening daemon, the
2749process id is not written to the normal pid file path. However, &%-oP%& can be
168e428f 2750used to specify a path on the command line if a pid file is required.
9b371988 2751
168e428f 2752The SIGHUP signal
9b371988 2753.cindex "SIGHUP"
3cb1b51e
PH
2754.cindex "daemon" "restarting"
2755can be used to cause the daemon to re-execute itself. This should be done
2756whenever Exim's configuration file, or any file that is incorporated into it by
2757means of the &%.include%& facility, is changed, and also whenever a new version
2758of Exim is installed. It is not necessary to do this when other files that are
9b371988
PH
2759referenced from the configuration (for example, alias files) are changed,
2760because these are reread each time they are used.
2761
2762.vitem &%-bdf%&
2763.oindex "&%-bdf%&"
2764This option has the same effect as &%-bd%& except that it never disconnects
2765from the controlling terminal, even when no debugging is specified.
2766
2767.vitem &%-be%&
2768.oindex "&%-be%&"
2769.cindex "testing" "string expansion"
2770.cindex "expansion" "testing"
168e428f
PH
2771Run Exim in expansion testing mode. Exim discards its root privilege, to
2772prevent ordinary users from using this mode to read otherwise inaccessible
2773files. If no arguments are given, Exim runs interactively, prompting for lines
4f578862 2774of data. Otherwise, it processes each argument in turn.
9b371988
PH
2775
2776If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2777to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2778used without command line arguments. If successful, it uses the &[readline()]&
168e428f
PH
2779function, which provides extensive line-editing facilities, for reading the
2780test data. A line history is supported.
9b371988 2781
168e428f 2782Long expansion expressions can be split over several lines by using backslash
068aaea8 2783continuations. As in Exim's run time configuration, white space at the start of
168e428f
PH
2784continuation lines is ignored. Each argument or data line is passed through the
2785string expansion mechanism, and the result is output. Variable values from the
9b371988 2786configuration file (for example, &$qualify_domain$&) are available, but no
3cb1b51e 2787message-specific values (such as &$sender_domain$&) are set, because no message
f89d2485 2788is being processed (but see &%-bem%& and &%-Mset%&).
168e428f 2789
9b371988
PH
2790&*Note*&: If you use this mechanism to test lookups, and you change the data
2791files or databases you are using, you must exit and restart Exim before trying
2792the same lookup again. Otherwise, because each Exim process caches the results
2793of lookups, you will just get the same result as before.
9b371988 2794
3cb1b51e
PH
2795.vitem &%-bem%&&~<&'filename'&>
2796.oindex "&%-bem%&"
2797.cindex "testing" "string expansion"
2798.cindex "expansion" "testing"
2799This option operates like &%-be%& except that it must be followed by the name
2800of a file. For example:
2801.code
2802exim -bem /tmp/testmessage
2803.endd
2804The file is read as a message (as if receiving a locally-submitted non-SMTP
2805message) before any of the test expansions are done. Thus, message-specific
2806variables such as &$message_size$& and &$header_from:$& are available. However,
2807no &'Received:'& header is added to the message. If the &%-t%& option is set,
2808recipients are read from the headers in the normal way, and are shown in the
2809&$recipients$& variable. Note that recipients cannot be given on the command
2810line, because further arguments are taken as strings to expand (just like
2811&%-be%&).
3cb1b51e 2812
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2813.vitem &%-bF%&&~<&'filename'&>
2814.oindex "&%-bF%&"
2815.cindex "system filter" "testing"
2816.cindex "testing" "system filter"
2817This option is the same as &%-bf%& except that it assumes that the filter being
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2818tested is a system filter. The additional commands that are available only in
2819system filters are recognized.
2820
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2821.vitem &%-bf%&&~<&'filename'&>
2822.oindex "&%-bf%&"
2823.cindex "filter" "testing"
2824.cindex "testing" "filter file"
2825.cindex "forward file" "testing"
2826.cindex "testing" "forward file"
2827.cindex "Sieve filter" "testing"
168e428f
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2828This option runs Exim in user filter testing mode; the file is the filter file
2829to be tested, and a test message must be supplied on the standard input. If
2830there are no message-dependent tests in the filter, an empty file can be
2831supplied.
168e428f 2832
9b371988
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2833If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2834can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2835filter and a user filter in the same run. For example:
2836.code
2837exim -bF /system/filter -bf /user/filter </test/message
2838.endd
168e428f
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2839This is helpful when the system filter adds header lines or sets filter
2840variables that are used by the user filter.
168e428f 2841
9b371988
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2842If the test filter file does not begin with one of the special lines
2843.code
2844# Exim filter
2845# Sieve filter
2846.endd
2847it is taken to be a normal &_.forward_& file, and is tested for validity under
2848that interpretation. See sections &<<SECTitenonfilred>>& to
2849&<<SECTspecitredli>>& for a description of the possible contents of non-filter
2850redirection lists.
2851
2852The result of an Exim command that uses &%-bf%&, provided no errors are
168e428f
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2853detected, is a list of the actions that Exim would try to take if presented
2854with the message for real. More details of filter testing are given in the
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2855separate document entitled &'Exim's interfaces to mail filtering'&.
2856
168e428f 2857When testing a filter file,
9b371988
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2858.cindex "&""From""& line"
2859.cindex "envelope sender"
f89d2485 2860.oindex "&%-f%&" "for filter testing"
9b371988
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2861the envelope sender can be set by the &%-f%& option,
2862or by a &"From&~"& line at the start of the test message. Various parameters
2863that would normally be taken from the envelope recipient address of the message
2864can be set by means of additional command line options (see the next four
2865options).
2866
2867.vitem &%-bfd%&&~<&'domain'&>
2868.oindex "&%-bfd%&"
f89d2485 2869.vindex "&$qualify_domain$&"
168e428f 2870This sets the domain of the recipient address when a filter file is being
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2871tested by means of the &%-bf%& option. The default is the value of
2872&$qualify_domain$&.
168e428f 2873
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2874.vitem &%-bfl%&&~<&'local&~part'&>
2875.oindex "&%-bfl%&"
168e428f 2876This sets the local part of the recipient address when a filter file is being
9b371988 2877tested by means of the &%-bf%& option. The default is the username of the
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2878process that calls Exim. A local part should be specified with any prefix or
2879suffix stripped, because that is how it appears to the filter when a message is
2880actually being delivered.
2881
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2882.vitem &%-bfp%&&~<&'prefix'&>
2883.oindex "&%-bfp%&"
168e428f 2884This sets the prefix of the local part of the recipient address when a filter
9b371988 2885file is being tested by means of the &%-bf%& option. The default is an empty
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2886prefix.
2887
9b371988
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2888.vitem &%-bfs%&&~<&'suffix'&>
2889.oindex "&%-bfs%&"
168e428f 2890This sets the suffix of the local part of the recipient address when a filter
9b371988 2891file is being tested by means of the &%-bf%& option. The default is an empty
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2892suffix.
2893
9b371988
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2894.vitem &%-bh%&&~<&'IP&~address'&>
2895.oindex "&%-bh%&"
2896.cindex "testing" "incoming SMTP"
2897.cindex "SMTP" "testing incoming"
2898.cindex "testing" "relay control"
2899.cindex "relaying" "testing configuration"
2900.cindex "policy control" "testing"
2901.cindex "debugging" "&%-bh%& option"
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2902This option runs a fake SMTP session as if from the given IP address, using the
2903standard input and output. The IP address may include a port number at the end,
2904after a full stop. For example:
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2905.code
2906exim -bh 10.9.8.7.1234
2907exim -bh fe80::a00:20ff:fe86:a061.5678
2908.endd
168e428f 2909When an IPv6 address is given, it is converted into canonical form. In the case
9b371988
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2910of the second example above, the value of &$sender_host_address$& after
2911conversion to the canonical form is
2912&`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2913
168e428f 2914Comments as to what is going on are written to the standard error file. These
9b371988 2915include lines beginning with &"LOG"& for anything that would have been logged.
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2916This facility is provided for testing configuration options for incoming
2917messages, to make sure they implement the required policy. For example, you can
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2918test your relay controls using &%-bh%&.
2919
2920&*Warning 1*&:
2921.cindex "RFC 1413"
db9452a9
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2922You can test features of the configuration that rely on ident (RFC 1413)
2923information by using the &%-oMt%& option. However, Exim cannot actually perform
2924an ident callout when testing using &%-bh%& because there is no incoming SMTP
2925connection.
9b371988
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2926
2927&*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2928are also skipped when testing using &%-bh%&. If you want these callouts to
2929occur, use &%-bhc%& instead.
2930
168e428f
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2931Messages supplied during the testing session are discarded, and nothing is
2932written to any of the real log files. There may be pauses when DNS (and other)
9b371988 2933lookups are taking place, and of course these may time out. The &%-oMi%& option
db9452a9
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2934can be used to specify a specific IP interface and port if this is important,
2935and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2936session were authenticated.
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2937
2938The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
168e428f 2939output just states whether a given recipient address from a given host is
9b371988 2940acceptable or not. See section &<<SECTcheckaccess>>&.
168e428f 2941
3cb1b51e 2942Features such as authentication and encryption, where the client input is not
f89d2485
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2943plain text, cannot easily be tested with &%-bh%&. Instead, you should use a
2944specialized SMTP test program such as
3cb1b51e 2945&url(http://jetmore.org/john/code/#swaks,swaks).
3cb1b51e 2946
9b371988
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2947.vitem &%-bhc%&&~<&'IP&~address'&>
2948.oindex "&%-bhc%&"
2949This option operates in the same way as &%-bh%&, except that address
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2950verification callouts are performed if required. This includes consulting and
2951updating the callout cache database.
2952
9b371988
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2953.vitem &%-bi%&
2954.oindex "&%-bi%&"
2955.cindex "alias file" "building"
2956.cindex "building alias file"
2957.cindex "Sendmail compatibility" "&%-bi%& option"
2958Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
168e428f 2959Exim does not have the concept of a single alias file, and so it cannot mimic
9b371988 2960this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
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2961tend to appear in various scripts such as NIS make files, so the option must be
2962recognized.
9b371988
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2963
2964If &%-bi%& is encountered, the command specified by the &%bi_command%&
168e428f 2965configuration option is run, under the uid and gid of the caller of Exim. If
9b371988
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2966the &%-oA%& option is used, its value is passed to the command as an argument.
2967The command set by &%bi_command%& may not contain arguments. The command can
2968use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2969if this is required. If the &%bi_command%& option is not set, calling Exim with
2970&%-bi%& is a no-op.
2971
12f69989 2972.new
36a3ae5f 2973. // Keep :help first, then the rest in alphabetical order
98a90c36
PP
2974.vitem &%-bI:help%&
2975.oindex "&%-bI:help%&"
2976.cindex "querying exim information"
2977We shall provide various options starting &`-bI:`& for querying Exim for
2978information. The output of many of these will be intended for machine
2979consumption. This one is not. The &%-bI:help%& option asks Exim for a
2980synopsis of supported options beginning &`-bI:`&. Use of any of these
2981options shall cause Exim to exit after producing the requested output.
2982
36a3ae5f
PP
2983.vitem &%-bI:dscp%&
2984.oindex "&%-bI:dscp%&"
2985.cindex "DSCP" "values"
2986This option causes Exim to emit an alphabetically sorted list of all
2987recognised DSCP names.
2988
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PP
2989.vitem &%-bI:sieve%&
2990.oindex "&%-bI:sieve%&"
2991.cindex "Sieve filter" "capabilities"
2992This option causes Exim to emit an alphabetically sorted list of all supported
2993Sieve protocol extensions on stdout, one per line. This is anticipated to be
2994useful for ManageSieve (RFC 5804) implementations, in providing that protocol's
2995&`SIEVE`& capability response line. As the precise list may depend upon
2996compile-time build options, which this option will adapt to, this is the only
2997way to guarantee a correct response.
12f69989 2998.wen
98a90c36 2999
9b371988
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3000.vitem &%-bm%&
3001.oindex "&%-bm%&"
3002.cindex "local message reception"
168e428f 3003This option runs an Exim receiving process that accepts an incoming,
a543079f 3004locally-generated message on the standard input. The recipients are given as the
9b371988 3005command arguments (except when &%-t%& is also present &-- see below). Each
168e428f
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3006argument can be a comma-separated list of RFC 2822 addresses. This is the
3007default option for selecting the overall action of an Exim call; it is assumed
3008if no other conflicting option is present.
9b371988 3009
168e428f 3010If any addresses in the message are unqualified (have no domain), they are
9b371988
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3011qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
3012options, as appropriate. The &%-bnq%& option (see below) provides a way of
168e428f 3013suppressing this for special cases.
9b371988 3014
168e428f 3015Policy checks on the contents of local messages can be enforced by means of
9b371988
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3016the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
3017
3018.cindex "return code" "for &%-bm%&"
3019The return code is zero if the message is successfully accepted. Otherwise, the
3020action is controlled by the &%-oe%&&'x'& option setting &-- see below.
3021
168e428f 3022The format
9b371988
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3023.cindex "message" "format"
3024.cindex "format" "message"
3025.cindex "&""From""& line"
3026.cindex "UUCP" "&""From""& line"
3027.cindex "Sendmail compatibility" "&""From""& line"
168e428f
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3028of the message must be as defined in RFC 2822, except that, for
3029compatibility with Sendmail and Smail, a line in one of the forms
9b371988
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3030.code
3031From sender Fri Jan 5 12:55 GMT 1997
3032From sender Fri, 5 Jan 97 12:55:01
3033.endd
168e428f
PH
3034(with the weekday optional, and possibly with additional text after the date)
3035is permitted to appear at the start of the message. There appears to be no
3036authoritative specification of the format of this line. Exim recognizes it by
9b371988 3037matching against the regular expression defined by the &%uucp_from_pattern%&
168e428f 3038option, which can be changed if necessary.
9b371988 3039
f89d2485
PH
3040.oindex "&%-f%&" "overriding &""From""& line"
3041The specified sender is treated as if it were given as the argument to the
9b371988 3042&%-f%& option, but if a &%-f%& option is also present, its argument is used in
168e428f
PH
3043preference to the address taken from the message. The caller of Exim must be a
3044trusted user for the sender of a message to be set in this way.
3045
5b257915
PP
3046.vitem &%-bmalware%&&~<&'filename'&>
3047.oindex "&%-bmalware%&"
3048.cindex "testing", "malware"
3049.cindex "malware scan test"
3050This debugging option causes Exim to scan the given file,
3051using the malware scanning framework. The option of &%av_scanner%& influences
3052this option, so if &%av_scanner%&'s value is dependent upon an expansion then
3053the expansion should have defaults which apply to this invocation. ACLs are
3054not invoked, so if &%av_scanner%& references an ACL variable then that variable
3055will never be populated and &%-bmalware%& will fail.
3056
3057Exim will have changed working directory before resolving the filename, so
3058using fully qualified pathnames is advisable. Exim will be running as the Exim
3059user when it tries to open the file, rather than as the invoking user.
3060This option requires admin privileges.
3061
3062The &%-bmalware%& option will not be extended to be more generally useful,
3063there are better tools for file-scanning. This option exists to help
3064administrators verify their Exim and AV scanner configuration.
3065
9b371988
PH
3066.vitem &%-bnq%&
3067.oindex "&%-bnq%&"
f89d2485 3068.cindex "address qualification, suppressing"
168e428f
PH
3069By default, Exim automatically qualifies unqualif