Typo & nit fixes.
[exim.git] / doc / doc-docbook / spec.xfpt
CommitLineData
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1. /////////////////////////////////////////////////////////////////////////////
2. This is the primary source of the Exim Manual. It is an xfpt document that is
3. converted into DocBook XML for subsequent conversion into printing and online
4. formats. The markup used herein is "standard" xfpt markup, with some extras.
5. The markup is summarized in a file called Markup.txt.
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6.
7. WARNING: When you use the .new macro, make sure it appears *before* any
8. adjacent index items; otherwise you get an empty "paragraph" which causes
9. unwanted vertical space.
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10. /////////////////////////////////////////////////////////////////////////////
11
12.include stdflags
13.include stdmacs
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14
15. /////////////////////////////////////////////////////////////////////////////
33393583 16. This outputs the standard DocBook boilerplate.
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17. /////////////////////////////////////////////////////////////////////////////
18
33393583 19.docbook
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20
21. /////////////////////////////////////////////////////////////////////////////
22. These lines are processing instructions for the Simple DocBook Processor that
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23. Philip Hazel has developed as a less cumbersome way of making PostScript and
24. PDFs than using xmlto and fop. They will be ignored by all other XML
25. processors.
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26. /////////////////////////////////////////////////////////////////////////////
27
28.literal xml
29<?sdop
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30 foot_right_recto="&chaptertitle; (&chapternumber;)"
31 foot_right_verso="&chaptertitle; (&chapternumber;)"
3cb1b51e 32 toc_chapter_blanks="yes,yes"
595028e4 33 table_warn_overflow="overprint"
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34?>
35.literal off
9b371988 36
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37. /////////////////////////////////////////////////////////////////////////////
38. This generate the outermost <book> element that wraps then entire document.
39. /////////////////////////////////////////////////////////////////////////////
40
41.book
42
43. /////////////////////////////////////////////////////////////////////////////
2aee48d6 44. These definitions set some parameters and save some typing.
7d837ca7 45. Update the Copyright year (only) when changing content.
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46. /////////////////////////////////////////////////////////////////////////////
47
2341d632 48.set previousversion "4.80"
2aee48d6 49.include ./local_params
f89d2485 50
33393583 51.set ACL "access control lists (ACLs)"
f89d2485 52.set I "&nbsp;&nbsp;&nbsp;&nbsp;"
33393583 53
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54.macro copyyear
552012
56.endmacro
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57
58. /////////////////////////////////////////////////////////////////////////////
59. Additional xfpt markup used by this document, over and above the default
60. provided in the xfpt library.
61. /////////////////////////////////////////////////////////////////////////////
62
63. --- Override the &$ flag to automatically insert a $ with the variable name
64
65.flag &$ $& "<varname>$" "</varname>"
66
67. --- Short flags for daggers in option headings. They will always be inside
68. --- an italic string, but we want the daggers to be roman.
69
70.flag &!! "</emphasis>&dagger;<emphasis>"
71.flag &!? "</emphasis>&Dagger;<emphasis>"
72
73. --- A macro for an Exim option definition heading, generating a one-line
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74. --- table with four columns. For cases when the option name is given with
75. --- a space, so that it can be split, a fifth argument is used for the
76. --- index entry.
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77
78.macro option
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79.arg 5
80.oindex "&%$5%&"
81.endarg
82.arg -5
3cb1b51e 83.oindex "&%$1%&"
0a4e3112 84.endarg
f89d2485 85.itable all 0 0 4 8* left 6* center 6* center 6* right
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86.row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&"
87.endtable
88.endmacro
89
90. --- A macro for the common 2-column tables. The width of the first column
91. --- is suitable for the many tables at the start of the main options chapter;
92. --- the small number of other 2-column tables override it.
93
db9452a9 94.macro table2 196pt 254pt
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95.itable none 0 0 2 $1 left $2 left
96.endmacro
97
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98. --- A macro that generates .row, but puts &I; at the start of the first
99. --- argument, thus indenting it. Assume a minimum of two arguments, and
100. --- allow up to four arguments, which is as many as we'll ever need.
101
102.macro irow
103.arg 4
104.row "&I;$1" "$2" "$3" "$4"
105.endarg
106.arg -4
107.arg 3
108.row "&I;$1" "$2" "$3"
109.endarg
110.arg -3
111.row "&I;$1" "$2"
112.endarg
113.endarg
114.endmacro
115
116. --- Macros for option, variable, and concept index entries. For a "range"
117. --- style of entry, use .scindex for the start and .ecindex for the end. The
118. --- first argument of .scindex and the only argument of .ecindex must be the
119. --- ID that ties them together.
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120
121.macro cindex
122&<indexterm role="concept">&
123&<primary>&$1&</primary>&
124.arg 2
125&<secondary>&$2&</secondary>&
126.endarg
127&</indexterm>&
128.endmacro
129
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130.macro scindex
131&<indexterm role="concept" id="$1" class="startofrange">&
132&<primary>&$2&</primary>&
133.arg 3
134&<secondary>&$3&</secondary>&
135.endarg
136&</indexterm>&
137.endmacro
138
139.macro ecindex
140&<indexterm role="concept" startref="$1" class="endofrange"/>&
141.endmacro
142
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143.macro oindex
144&<indexterm role="option">&
145&<primary>&$1&</primary>&
146.arg 2
147&<secondary>&$2&</secondary>&
148.endarg
149&</indexterm>&
150.endmacro
151
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152.macro vindex
153&<indexterm role="variable">&
154&<primary>&$1&</primary>&
155.arg 2
156&<secondary>&$2&</secondary>&
157.endarg
158&</indexterm>&
159.endmacro
160
9b371988 161.macro index
f89d2485 162.echo "** Don't use .index; use .cindex or .oindex or .vindex"
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163.endmacro
164. ////////////////////////////////////////////////////////////////////////////
165
166
167. ////////////////////////////////////////////////////////////////////////////
168. The <bookinfo> element is removed from the XML before processing for Ascii
169. output formats.
170. ////////////////////////////////////////////////////////////////////////////
171
172.literal xml
173<bookinfo>
174<title>Specification of the Exim Mail Transfer Agent</title>
175<titleabbrev>The Exim MTA</titleabbrev>
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176<date>
177.fulldate
178</date>
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179<author><firstname>Exim</firstname><surname>Maintainers</surname></author>
180<authorinitials>EM</authorinitials>
9b371988 181<revhistory><revision>
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182 <revnumber>
183.version
184 </revnumber>
185 <date>
186.fulldate
187 </date>
7b4c60eb 188 <authorinitials>EM</authorinitials>
9b371988 189</revision></revhistory>
2aee48d6 190<copyright><year>
29343b08 191.copyyear
2aee48d6 192 </year><holder>University of Cambridge</holder></copyright>
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193</bookinfo>
194.literal off
195
196
197. /////////////////////////////////////////////////////////////////////////////
198. This chunk of literal XML implements index entries of the form "x, see y" and
199. "x, see also y". However, the DocBook DTD doesn't allow <indexterm> entries
200. at the top level, so we have to put the .chapter directive first.
201. /////////////////////////////////////////////////////////////////////////////
202
f89d2485 203.chapter "Introduction" "CHID1"
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204.literal xml
205
f89d2485 206<indexterm role="variable">
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207 <primary>$1, $2, etc.</primary>
208 <see><emphasis>numerical variables</emphasis></see>
209</indexterm>
210<indexterm role="concept">
211 <primary>address</primary>
212 <secondary>rewriting</secondary>
213 <see><emphasis>rewriting</emphasis></see>
214</indexterm>
215<indexterm role="concept">
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216 <primary>Bounce Address Tag Validation</primary>
217 <see><emphasis>BATV</emphasis></see>
218</indexterm>
219<indexterm role="concept">
220 <primary>Client SMTP Authorization</primary>
221 <see><emphasis>CSA</emphasis></see>
222</indexterm>
223<indexterm role="concept">
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224 <primary>CR character</primary>
225 <see><emphasis>carriage return</emphasis></see>
226</indexterm>
227<indexterm role="concept">
228 <primary>CRL</primary>
229 <see><emphasis>certificate revocation list</emphasis></see>
230</indexterm>
231<indexterm role="concept">
232 <primary>delivery</primary>
233 <secondary>failure report</secondary>
234 <see><emphasis>bounce message</emphasis></see>
235</indexterm>
236<indexterm role="concept">
237 <primary>dialup</primary>
238 <see><emphasis>intermittently connected hosts</emphasis></see>
239</indexterm>
240<indexterm role="concept">
241 <primary>exiscan</primary>
242 <see><emphasis>content scanning</emphasis></see>
243</indexterm>
244<indexterm role="concept">
245 <primary>failover</primary>
246 <see><emphasis>fallback</emphasis></see>
247</indexterm>
248<indexterm role="concept">
249 <primary>fallover</primary>
250 <see><emphasis>fallback</emphasis></see>
251</indexterm>
252<indexterm role="concept">
253 <primary>filter</primary>
254 <secondary>Sieve</secondary>
255 <see><emphasis>Sieve filter</emphasis></see>
256</indexterm>
257<indexterm role="concept">
258 <primary>ident</primary>
259 <see><emphasis>RFC 1413</emphasis></see>
260</indexterm>
261<indexterm role="concept">
262 <primary>LF character</primary>
263 <see><emphasis>linefeed</emphasis></see>
264</indexterm>
265<indexterm role="concept">
266 <primary>maximum</primary>
595028e4 267 <seealso><emphasis>limit</emphasis></seealso>
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268</indexterm>
269<indexterm role="concept">
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270 <primary>monitor</primary>
271 <see><emphasis>Exim monitor</emphasis></see>
272</indexterm>
273<indexterm role="concept">
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274 <primary>no_<emphasis>xxx</emphasis></primary>
275 <see>entry for xxx</see>
276</indexterm>
277<indexterm role="concept">
278 <primary>NUL</primary>
279 <see><emphasis>binary zero</emphasis></see>
280</indexterm>
281<indexterm role="concept">
282 <primary>passwd file</primary>
283 <see><emphasis>/etc/passwd</emphasis></see>
284</indexterm>
285<indexterm role="concept">
286 <primary>process id</primary>
287 <see><emphasis>pid</emphasis></see>
288</indexterm>
289<indexterm role="concept">
290 <primary>RBL</primary>
291 <see><emphasis>DNS list</emphasis></see>
292</indexterm>
293<indexterm role="concept">
294 <primary>redirection</primary>
295 <see><emphasis>address redirection</emphasis></see>
296</indexterm>
297<indexterm role="concept">
298 <primary>return path</primary>
299 <seealso><emphasis>envelope sender</emphasis></seealso>
300</indexterm>
301<indexterm role="concept">
302 <primary>scanning</primary>
303 <see><emphasis>content scanning</emphasis></see>
304</indexterm>
305<indexterm role="concept">
306 <primary>SSL</primary>
307 <see><emphasis>TLS</emphasis></see>
308</indexterm>
309<indexterm role="concept">
310 <primary>string</primary>
311 <secondary>expansion</secondary>
312 <see><emphasis>expansion</emphasis></see>
313</indexterm>
314<indexterm role="concept">
315 <primary>top bit</primary>
316 <see><emphasis>8-bit characters</emphasis></see>
317</indexterm>
318<indexterm role="concept">
319 <primary>variables</primary>
320 <see><emphasis>expansion, variables</emphasis></see>
321</indexterm>
322<indexterm role="concept">
323 <primary>zero, binary</primary>
324 <see><emphasis>binary zero</emphasis></see>
325</indexterm>
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326
327.literal off
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328
329
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330. /////////////////////////////////////////////////////////////////////////////
331. This is the real start of the first chapter. See the comment above as to why
332. we can't have the .chapter line here.
333. chapter "Introduction"
334. /////////////////////////////////////////////////////////////////////////////
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335
336Exim is a mail transfer agent (MTA) for hosts that are running Unix or
337Unix-like operating systems. It was designed on the assumption that it would be
338run on hosts that are permanently connected to the Internet. However, it can be
339used on intermittently connected hosts with suitable configuration adjustments.
340
341Configuration files currently exist for the following operating systems: AIX,
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342BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, Dragonfly, FreeBSD, GNU/Hurd,
343GNU/Linux, HI-OSF (Hitachi), HI-UX, HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD,
344OpenUNIX, QNX, SCO, SCO SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4,
345Tru64-Unix (formerly Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware.
346Some of these operating systems are no longer current and cannot easily be
347tested, so the configuration files may no longer work in practice.
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348
349There are also configuration files for compiling Exim in the Cygwin environment
350that can be installed on systems running Windows. However, this document does
351not contain any information about running Exim in the Cygwin environment.
352
353The terms and conditions for the use and distribution of Exim are contained in
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354the file &_NOTICE_&. Exim is distributed under the terms of the GNU General
355Public Licence, a copy of which may be found in the file &_LICENCE_&.
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356
357The use, supply or promotion of Exim for the purpose of sending bulk,
358unsolicited electronic mail is incompatible with the basic aims of the program,
359which revolve around the free provision of a service that enhances the quality
360of personal communications. The author of Exim regards indiscriminate
361mass-mailing as an antisocial, irresponsible abuse of the Internet.
362
363Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
364experience of running and working on the Smail 3 code, I could never have
365contemplated starting to write a new MTA. Many of the ideas and user interfaces
366were originally taken from Smail 3, though the actual code of Exim is entirely
367new, and has developed far beyond the initial concept.
368
369Many people, both in Cambridge and around the world, have contributed to the
370development and the testing of Exim, and to porting it to various operating
371systems. I am grateful to them all. The distribution now contains a file called
9b371988 372&_ACKNOWLEDGMENTS_&, in which I have started recording the names of
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373contributors.
374
375
f89d2485 376.section "Exim documentation" "SECID1"
800d5176 377. Keep this example change bar when updating the documentation!
b52ed2b3 378
800d5176 379.new
9b371988 380.cindex "documentation"
2aee48d6 381This edition of the Exim specification applies to version &version() of Exim.
9b371988 382Substantive changes from the &previousversion; edition are marked in some
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383renditions of the document; this paragraph is so marked if the rendition is
384capable of showing a change indicator.
800d5176 385.wen
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386
387This document is very much a reference manual; it is not a tutorial. The reader
388is expected to have some familiarity with the SMTP mail transfer protocol and
389with general Unix system administration. Although there are some discussions
390and examples in places, the information is mostly organized in a way that makes
391it easy to look up, rather than in a natural order for sequential reading.
392Furthermore, the manual aims to cover every aspect of Exim in detail, including
393a number of rarely-used, special-purpose features that are unlikely to be of
394very wide interest.
395
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396.cindex "books about Exim"
397An &"easier"& discussion of Exim which provides more in-depth explanatory,
398introductory, and tutorial material can be found in a book entitled &'The Exim
595028e4 399SMTP Mail Server'& (second edition, 2007), published by UIT Cambridge
9b371988 400(&url(http://www.uit.co.uk/exim-book/)).
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401
402This book also contains a chapter that gives a general introduction to SMTP and
403Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
404with the latest release of Exim. (Note that the earlier book about Exim,
405published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
406
9b371988 407.cindex "Debian" "information sources"
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408If you are using a Debian distribution of Exim, you will find information about
409Debian-specific features in the file
f89d2485 410&_/usr/share/doc/exim4-base/README.Debian_&.
9b371988 411The command &(man update-exim.conf)& is another source of Debian-specific
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412information.
413
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414.cindex "&_doc/NewStuff_&"
415.cindex "&_doc/ChangeLog_&"
416.cindex "change log"
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417As the program develops, there may be features in newer versions that have not
418yet made it into this document, which is updated only when the most significant
419digit of the fractional part of the version number changes. Specifications of
420new features that are not yet in this manual are placed in the file
9b371988 421&_doc/NewStuff_& in the Exim distribution.
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9b371988 423Some features may be classified as &"experimental"&. These may change
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424incompatibly while they are developing, or even be withdrawn. For this reason,
425they are not documented in this manual. Information about experimental features
9b371988 426can be found in the file &_doc/experimental.txt_&.
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427
428All changes to the program (whether new features, bug fixes, or other kinds of
9b371988 429change) are noted briefly in the file called &_doc/ChangeLog_&.
168e428f 430
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431.cindex "&_doc/spec.txt_&"
432This specification itself is available as an ASCII file in &_doc/spec.txt_& so
433that it can easily be searched with a text editor. Other files in the &_doc_&
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434directory are:
435
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436.table2 100pt
437.row &_OptionLists.txt_& "list of all options in alphabetical order"
438.row &_dbm.discuss.txt_& "discussion about DBM libraries"
439.row &_exim.8_& "a man page of Exim's command line options"
440.row &_experimental.txt_& "documentation of experimental features"
441.row &_filter.txt_& "specification of the filter language"
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442.row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
443.row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
444.endtable
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445
446The main specification and the specification of the filtering language are also
447available in other formats (HTML, PostScript, PDF, and Texinfo). Section
9b371988 448&<<SECTavail>>& below tells you how to get hold of these.
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449
450
451
f89d2485 452.section "FTP and web sites" "SECID2"
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453.cindex "web site"
454.cindex "FTP site"
068aaea8 455The primary site for Exim source distributions is currently the University of
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456Cambridge's FTP site, whose contents are described in &'Where to find the Exim
457distribution'& below. In addition, there is a web site and an FTP site at
458&%exim.org%&. These are now also hosted at the University of Cambridge. The
459&%exim.org%& site was previously hosted for a number of years by Energis
460Squared, formerly Planet Online Ltd, whose support I gratefully acknowledge.
461
462.cindex "wiki"
463.cindex "FAQ"
168e428f 464As well as Exim distribution tar files, the Exim web site contains a number of
f89d2485 465differently formatted versions of the documentation. A recent addition to the
7d0ab55c 466online information is the Exim wiki (&url(http://wiki.exim.org)),
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467which contains what used to be a separate FAQ, as well as various other
468examples, tips, and know-how that have been contributed by Exim users.
469
470.cindex Bugzilla
7d0ab55c 471An Exim Bugzilla exists at &url(http://bugs.exim.org). You can use
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472this to report bugs, and also to add items to the wish list. Please search
473first to check that you are not duplicating a previous entry.
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474
475
476
f89d2485 477.section "Mailing lists" "SECID3"
9b371988 478.cindex "mailing lists" "for Exim users"
f89d2485 479The following Exim mailing lists exist:
168e428f 480
9b371988 481.table2 140pt
d854d3a9 482.row &'exim-announce@exim.org'& "Moderated, low volume announcements list"
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483.row &'exim-users@exim.org'& "General discussion list"
484.row &'exim-dev@exim.org'& "Discussion of bugs, enhancements, etc."
d854d3a9 485.row &'exim-cvs@exim.org'& "Automated commit messages from the VCS"
9b371988 486.endtable
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487
488You can subscribe to these lists, change your existing subscriptions, and view
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489or search the archives via the mailing lists link on the Exim home page.
490.cindex "Debian" "mailing list for"
4f578862 491If you are using a Debian distribution of Exim, you may wish to subscribe to
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492the Debian-specific mailing list &'pkg-exim4-users@lists.alioth.debian.org'&
493via this web page:
494.display
495&url(http://lists.alioth.debian.org/mailman/listinfo/pkg-exim4-users)
496.endd
497Please ask Debian-specific questions on this list and not on the general Exim
498lists.
9b371988 499
f89d2485 500.section "Exim training" "SECID4"
9b371988 501.cindex "training courses"
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502Training courses in Cambridge (UK) used to be run annually by the author of
503Exim, before he retired. At the time of writing, there are no plans to run
504further Exim courses in Cambridge. However, if that changes, relevant
505information will be posted at &url(http://www-tus.csx.cam.ac.uk/courses/exim/).
168e428f 506
f89d2485 507.section "Bug reports" "SECID5"
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508.cindex "bug reports"
509.cindex "reporting bugs"
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510Reports of obvious bugs can be emailed to &'bugs@exim.org'& or reported
511via the Bugzilla (&url(http://bugs.exim.org)). However, if you are unsure
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512whether some behaviour is a bug or not, the best thing to do is to post a
513message to the &'exim-dev'& mailing list and have it discussed.
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514
515
516
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517.section "Where to find the Exim distribution" "SECTavail"
518.cindex "FTP site"
519.cindex "distribution" "ftp site"
168e428f 520The master ftp site for the Exim distribution is
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521.display
522&*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim*&
523.endd
168e428f 524This is mirrored by
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525.display
526&*ftp://ftp.exim.org/pub/exim*&
527.endd
528The file references that follow are relative to the &_exim_& directories at
529these sites. There are now quite a number of independent mirror sites around
530the world. Those that I know about are listed in the file called &_Mirrors_&.
531
532Within the &_exim_& directory there are subdirectories called &_exim3_& (for
533previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
534distributions), and &_Testing_& for testing versions. In the &_exim4_&
168e428f 535subdirectory, the current release can always be found in files called
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536.display
537&_exim-n.nn.tar.gz_&
538&_exim-n.nn.tar.bz2_&
539.endd
540where &'n.nn'& is the highest such version number in the directory. The two
168e428f 541files contain identical data; the only difference is the type of compression.
9b371988 542The &_.bz2_& file is usually a lot smaller than the &_.gz_& file.
168e428f 543
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544.cindex "distribution" "signing details"
545.cindex "distribution" "public key"
546.cindex "public key for signed distribution"
40167b05
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547.new
548The distributions will be PGP signed by an individual key of the Release
549Coordinator. This key will have a uid containing an email address in the
550&'exim.org'& domain and will have signatures from other people, including
551other Exim maintainers. We expect that the key will be in the "strong set" of
552PGP keys. There should be a trust path to that key from Nigel Metheringham's
553PGP key, a version of which can be found in the release directory in the file
554&_nigel-pubkey.asc_&. All keys used will be available in public keyserver pools,
555such as &'pool.sks-keyservers.net'&.
556
557At time of last update, releases were being made by Phil Pennock and signed with
558key &'0x403043153903637F'&, although that key is expected to be replaced in 2013.
559A trust path from Nigel's key to Phil's can be observed at
560&url(https://www.security.spodhuis.org/exim-trustpath).
561.wen
562
563The signatures for the tar bundles are in:
9b371988 564.display
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565&_exim-n.nn.tar.gz.asc_&
566&_exim-n.nn.tar.bz2.asc_&
9b371988 567.endd
168e428f 568For each released version, the log of changes is made separately available in a
9b371988 569separate file in the directory &_ChangeLogs_& so that it is possible to
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570find out what has changed without having to download the entire distribution.
571
9b371988 572.cindex "documentation" "available formats"
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573The main distribution contains ASCII versions of this specification and other
574documentation; other formats of the documents are available in separate files
9b371988
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575inside the &_exim4_& directory of the FTP site:
576.display
577&_exim-html-n.nn.tar.gz_&
578&_exim-pdf-n.nn.tar.gz_&
579&_exim-postscript-n.nn.tar.gz_&
580&_exim-texinfo-n.nn.tar.gz_&
581.endd
582These tar files contain only the &_doc_& directory, not the complete
583distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
168e428f 584
168e428f 585
f89d2485 586.section "Limitations" "SECID6"
9b371988
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587.ilist
588.cindex "limitations of Exim"
589.cindex "bang paths" "not handled by Exim"
590Exim is designed for use as an Internet MTA, and therefore handles addresses in
591RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
592simple two-component bang paths can be converted by a straightforward rewriting
593configuration. This restriction does not prevent Exim from being interfaced to
594UUCP as a transport mechanism, provided that domain addresses are used.
595.next
596.cindex "domainless addresses"
597.cindex "address" "without domain"
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598Exim insists that every address it handles has a domain attached. For incoming
599local messages, domainless addresses are automatically qualified with a
600configured domain value. Configuration options specify from which remote
601systems unqualified addresses are acceptable. These are then qualified on
602arrival.
9b371988
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603.next
604.cindex "transport" "external"
605.cindex "external transports"
606The only external transport mechanisms that are currently implemented are SMTP
607and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
168e428f 608transport is available, and there are facilities for writing messages to files
9b371988
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609and pipes, optionally in &'batched SMTP'& format; these facilities can be used
610to send messages to other transport mechanisms such as UUCP, provided they can
611handle domain-style addresses. Batched SMTP input is also catered for.
612.next
613Exim is not designed for storing mail for dial-in hosts. When the volumes of
614such mail are large, it is better to get the messages &"delivered"& into files
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615(that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
616other means.
9b371988
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617.next
618Although Exim does have basic facilities for scanning incoming messages, these
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619are not comprehensive enough to do full virus or spam scanning. Such operations
620are best carried out using additional specialized software packages. If you
621compile Exim with the content-scanning extension, straightforward interfaces to
622a number of common scanners are provided.
9b371988 623.endlist
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624
625
f89d2485 626.section "Run time configuration" "SECID7"
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627Exim's run time configuration is held in a single text file that is divided
628into a number of sections. The entries in this file consist of keywords and
629values, in the style of Smail 3 configuration files. A default configuration
630file which is suitable for simple online installations is provided in the
9b371988 631distribution, and is described in chapter &<<CHAPdefconfil>>& below.
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632
633
f89d2485 634.section "Calling interface" "SECID8"
9b371988 635.cindex "Sendmail compatibility" "command line interface"
168e428f 636Like many MTAs, Exim has adopted the Sendmail command line interface so that it
9b371988
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637can be a straight replacement for &_/usr/lib/sendmail_& or
638&_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
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639about Sendmail in order to run Exim. For actions other than sending messages,
640Sendmail-compatible options also exist, but those that produce output (for
9b371988 641example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
168e428f 642format. There are also some additional options that are compatible with Smail
9b371988 6433, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
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644documents all Exim's command line options. This information is automatically
645made into the man page that forms part of the Exim distribution.
646
647Control of messages on the queue can be done via certain privileged command
9b371988
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648line options. There is also an optional monitor program called &'eximon'&,
649which displays current information in an X window, and which contains a menu
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650interface to Exim's command line administration options.
651
652
653
f89d2485 654.section "Terminology" "SECID9"
9b371988
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655.cindex "terminology definitions"
656.cindex "body of message" "definition of"
657The &'body'& of a message is the actual data that the sender wants to transmit.
658It is the last part of a message, and is separated from the &'header'& (see
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659below) by a blank line.
660
9b371988 661.cindex "bounce message" "definition of"
168e428f 662When a message cannot be delivered, it is normally returned to the sender in a
9b371988
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663delivery failure message or a &"non-delivery report"& (NDR). The term
664&'bounce'& is commonly used for this action, and the error reports are often
665called &'bounce messages'&. This is a convenient shorthand for &"delivery
666failure error report"&. Such messages have an empty sender address in the
667message's &'envelope'& (see below) to ensure that they cannot themselves give
668rise to further bounce messages.
669
670The term &'default'& appears frequently in this manual. It is used to qualify a
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671value which is used in the absence of any setting in the configuration. It may
672also qualify an action which is taken unless a configuration setting specifies
673otherwise.
674
9b371988 675The term &'defer'& is used when the delivery of a message to a specific
168e428f 676destination cannot immediately take place for some reason (a remote host may be
9b371988 677down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
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678until a later time.
679
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680The word &'domain'& is sometimes used to mean all but the first component of a
681host's name. It is &'not'& used in that sense here, where it normally refers to
682the part of an email address following the @ sign.
168e428f 683
f89d2485 684.cindex "envelope, definition of"
9b371988
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685.cindex "sender" "definition of"
686A message in transit has an associated &'envelope'&, as well as a header and a
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687body. The envelope contains a sender address (to which bounce messages should
688be delivered), and any number of recipient addresses. References to the
689sender or the recipients of a message usually mean the addresses in the
690envelope. An MTA uses these addresses for delivery, and for returning bounce
691messages, not the addresses that appear in the header lines.
692
f89d2485 693.cindex "message" "header, definition of"
9b371988
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694.cindex "header section" "definition of"
695The &'header'& of a message is the first part of a message's text, consisting
696of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
697&'Subject:'&, etc. Long header lines can be split over several text lines by
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698indenting the continuations. The header is separated from the body by a blank
699line.
700
9b371988
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701.cindex "local part" "definition of"
702.cindex "domain" "definition of"
703The term &'local part'&, which is taken from RFC 2822, is used to refer to that
168e428f 704part of an email address that precedes the @ sign. The part that follows the
9b371988 705@ sign is called the &'domain'& or &'mail domain'&.
168e428f 706
9b371988 707.cindex "local delivery" "definition of"
f89d2485 708.cindex "remote delivery, definition of"
9b371988 709The terms &'local delivery'& and &'remote delivery'& are used to distinguish
168e428f 710delivery to a file or a pipe on the local host from delivery by SMTP over
068aaea8 711TCP/IP to another host. As far as Exim is concerned, all hosts other than the
9b371988 712host it is running on are &'remote'&.
168e428f 713
9b371988
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714.cindex "return path" "definition of"
715&'Return path'& is another name that is used for the sender address in a
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716message's envelope.
717
9b371988
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718.cindex "queue" "definition of"
719The term &'queue'& is used to refer to the set of messages awaiting delivery,
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720because this term is in widespread use in the context of MTAs. However, in
721Exim's case the reality is more like a pool than a queue, because there is
722normally no ordering of waiting messages.
723
9b371988
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724.cindex "queue runner" "definition of"
725The term &'queue runner'& is used to describe a process that scans the queue
168e428f 726and attempts to deliver those messages whose retry times have come. This term
9b371988 727is used by other MTAs, and also relates to the command &%runq%&, but in Exim
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728the waiting messages are normally processed in an unpredictable order.
729
9b371988
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730.cindex "spool directory" "definition of"
731The term &'spool directory'& is used for a directory in which Exim keeps the
732messages on its queue &-- that is, those that it is in the process of
168e428f 733delivering. This should not be confused with the directory in which local
9b371988
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734mailboxes are stored, which is called a &"spool directory"& by some people. In
735the Exim documentation, &"spool"& is always used in the first sense.
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736
737
738
739
740
741
9b371988
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742. ////////////////////////////////////////////////////////////////////////////
743. ////////////////////////////////////////////////////////////////////////////
168e428f 744
f89d2485 745.chapter "Incorporated code" "CHID2"
9b371988
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746.cindex "incorporated code"
747.cindex "regular expressions" "library"
748.cindex "PCRE"
168e428f
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749A number of pieces of external code are included in the Exim distribution.
750
9b371988 751.ilist
210f147e
NM
752Regular expressions are supported in the main Exim program and in the
753Exim monitor using the freely-distributable PCRE library, copyright
40df1be3
TF
754&copy; University of Cambridge. The source to PCRE is no longer shipped with
755Exim, so you will need to use the version of PCRE shipped with your system,
756or obtain and install the full version of the library from
f89d2485 757&url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
9b371988 758.next
f89d2485 759.cindex "cdb" "acknowledgment"
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760Support for the cdb (Constant DataBase) lookup method is provided by code
761contributed by Nigel Metheringham of (at the time he contributed it) Planet
9b371988
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762Online Ltd. The implementation is completely contained within the code of Exim.
763It does not link against an external cdb library. The code contains the
764following statements:
765
766.blockquote
767Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
768
168e428f
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769This program is free software; you can redistribute it and/or modify it under
770the terms of the GNU General Public License as published by the Free Software
771Foundation; either version 2 of the License, or (at your option) any later
772version.
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773This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
774the spec and sample code for cdb can be obtained from
f89d2485
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775&url(http://www.pobox.com/~djb/cdb.html). This implementation borrows
776some code from Dan Bernstein's implementation (which has no license
777restrictions applied to it).
9b371988
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778.endblockquote
779.next
780.cindex "SPA authentication"
781.cindex "Samba project"
782.cindex "Microsoft Secure Password Authentication"
783Client support for Microsoft's &'Secure Password Authentication'& is provided
168e428f
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784by code contributed by Marc Prud'hommeaux. Server support was contributed by
785Tom Kistner. This includes code taken from the Samba project, which is released
786under the Gnu GPL.
9b371988
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787.next
788.cindex "Cyrus"
789.cindex "&'pwcheck'& daemon"
790.cindex "&'pwauthd'& daemon"
791Support for calling the Cyrus &'pwcheck'& and &'saslauthd'& daemons is provided
168e428f
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792by code taken from the Cyrus-SASL library and adapted by Alexander S.
793Sabourenkov. The permission notice appears below, in accordance with the
794conditions expressed therein.
9b371988
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795
796.blockquote
797Copyright &copy; 2001 Carnegie Mellon University. All rights reserved.
798
168e428f
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799Redistribution and use in source and binary forms, with or without
800modification, are permitted provided that the following conditions
801are met:
168e428f 802
9b371988
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803.olist
804Redistributions of source code must retain the above copyright
805notice, this list of conditions and the following disclaimer.
806.next
807Redistributions in binary form must reproduce the above copyright
168e428f
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808notice, this list of conditions and the following disclaimer in
809the documentation and/or other materials provided with the
810distribution.
9b371988
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811.next
812The name &"Carnegie Mellon University"& must not be used to
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813endorse or promote products derived from this software without
814prior written permission. For permission or any other legal
815details, please contact
9b371988 816.display
068aaea8
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817 Office of Technology Transfer
818 Carnegie Mellon University
819 5000 Forbes Avenue
820 Pittsburgh, PA 15213-3890
821 (412) 268-4387, fax: (412) 268-7395
822 tech-transfer@andrew.cmu.edu
9b371988
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823.endd
824.next
825Redistributions of any form whatsoever must retain the following
168e428f 826acknowledgment:
9b371988
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827
828&"This product includes software developed by Computing Services
829at Carnegie Mellon University (&url(http://www.cmu.edu/computing/)."&
830
168e428f
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831CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
832THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
833AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
834FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
835WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
836AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
837OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
9b371988
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838.endlist
839.endblockquote
168e428f 840
9b371988 841.next
f89d2485 842.cindex "Exim monitor" "acknowledgment"
9b371988
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843.cindex "X-windows"
844.cindex "Athena"
168e428f
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845The Exim Monitor program, which is an X-Window application, includes
846modified versions of the Athena StripChart and TextPop widgets.
847This code is copyright by DEC and MIT, and their permission notice appears
848below, in accordance with the conditions expressed therein.
9b371988
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849
850.blockquote
168e428f
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851Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
852and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
9b371988 853
168e428f 854All Rights Reserved
9b371988 855
168e428f
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856Permission to use, copy, modify, and distribute this software and its
857documentation for any purpose and without fee is hereby granted,
858provided that the above copyright notice appear in all copies and that
859both that copyright notice and this permission notice appear in
860supporting documentation, and that the names of Digital or MIT not be
861used in advertising or publicity pertaining to distribution of the
862software without specific, written prior permission.
9b371988 863
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864DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
865ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
866DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
867ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
868WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
869ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
870SOFTWARE.
9b371988 871.endblockquote
168e428f 872
9b371988
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873.next
874Many people have contributed code fragments, some large, some small, that were
168e428f 875not covered by any specific licence requirements. It is assumed that the
f89d2485 876contributors are happy to see their code incorporated into Exim under the GPL.
9b371988 877.endlist
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878
879
880
881
882
9b371988
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883. ////////////////////////////////////////////////////////////////////////////
884. ////////////////////////////////////////////////////////////////////////////
168e428f 885
f89d2485 886.chapter "How Exim receives and delivers mail" "CHID11" &&&
9b371988 887 "Receiving and delivering mail"
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888
889
f89d2485 890.section "Overall philosophy" "SECID10"
9b371988 891.cindex "design philosophy"
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892Exim is designed to work efficiently on systems that are permanently connected
893to the Internet and are handling a general mix of mail. In such circumstances,
894most messages can be delivered immediately. Consequently, Exim does not
895maintain independent queues of messages for specific domains or hosts, though
896it does try to send several messages in a single SMTP connection after a host
897has been down, and it also maintains per-host retry information.
898
899
f89d2485 900.section "Policy control" "SECID11"
9b371988 901.cindex "policy control" "overview"
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902Policy controls are now an important feature of MTAs that are connected to the
903Internet. Perhaps their most important job is to stop MTAs being abused as
9b371988
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904&"open relays"& by misguided individuals who send out vast amounts of
905unsolicited junk, and want to disguise its source. Exim provides flexible
906facilities for specifying policy controls on incoming mail:
168e428f 907
9b371988
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908.ilist
909.cindex "&ACL;" "introduction"
168e428f 910Exim 4 (unlike previous versions of Exim) implements policy controls on
9b371988 911incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
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912series of statements that may either grant or deny access. ACLs can be used at
913several places in the SMTP dialogue while receiving a message from a remote
9b371988
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914host. However, the most common places are after each RCPT command, and at the
915very end of the message. The sysadmin can specify conditions for accepting or
916rejecting individual recipients or the entire message, respectively, at these
917two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
168e428f 918error code.
9b371988
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919.next
920An ACL is also available for locally generated, non-SMTP messages. In this
168e428f 921case, the only available actions are to accept or deny the entire message.
9b371988
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922.next
923When Exim is compiled with the content-scanning extension, facilities are
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924provided in the ACL mechanism for passing the message to external virus and/or
925spam scanning software. The result of such a scan is passed back to the ACL,
926which can then use it to decide what to do with the message.
9b371988
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927.next
928When a message has been received, either from a remote host or from the local
f89d2485 929host, but before the final acknowledgment has been sent, a locally supplied C
9b371988
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930function called &[local_scan()]& can be run to inspect the message and decide
931whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
932is accepted, the list of recipients can be modified by the function.
933.next
934Using the &[local_scan()]& mechanism is another way of calling external scanner
935software. The &%SA-Exim%& add-on package works this way. It does not require
936Exim to be compiled with the content-scanning extension.
937.next
938After a message has been accepted, a further checking mechanism is available in
939the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
940runs at the start of every delivery process.
941.endlist
942
943
944
f89d2485 945.section "User filters" "SECID12"
9b371988
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946.cindex "filter" "introduction"
947.cindex "Sieve filter"
168e428f 948In a conventional Exim configuration, users are able to run private filters by
9b371988
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949setting up appropriate &_.forward_& files in their home directories. See
950chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
951configuration needed to support this, and the separate document entitled
952&'Exim's interfaces to mail filtering'& for user details. Two different kinds
953of filtering are available:
954
955.ilist
956Sieve filters are written in the standard filtering language that is defined
168e428f 957by RFC 3028.
9b371988
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958.next
959Exim filters are written in a syntax that is unique to Exim, but which is more
168e428f 960powerful than Sieve, which it pre-dates.
9b371988 961.endlist
168e428f
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962
963User filters are run as part of the routing process, described below.
964
965
966
9b371988
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967.section "Message identification" "SECTmessiden"
968.cindex "message ids" "details of format"
969.cindex "format" "of message id"
970.cindex "id of message"
971.cindex "base62"
972.cindex "base36"
973.cindex "Darwin"
974.cindex "Cygwin"
975Every message handled by Exim is given a &'message id'& which is sixteen
168e428f 976characters long. It is divided into three parts, separated by hyphens, for
9b371988 977example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
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978normally encoding numbers in base 62. However, in the Darwin operating
979system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
980(avoiding the use of lower case letters) is used instead, because the message
981id is used to construct file names, and the names of files in those systems are
068aaea8 982not always case-sensitive.
168e428f 983
9b371988 984.cindex "pid (process id)" "re-use of"
168e428f
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985The detail of the contents of the message id have changed as Exim has evolved.
986Earlier versions relied on the operating system not re-using a process id (pid)
987within one second. On modern operating systems, this assumption can no longer
988be made, so the algorithm had to be changed. To retain backward compatibility,
989the format of the message id was retained, which is why the following rules are
990somewhat eccentric:
991
9b371988
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992.ilist
993The first six characters of the message id are the time at which the message
168e428f
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994started to be received, to a granularity of one second. That is, this field
995contains the number of seconds since the start of the epoch (the normal Unix
996way of representing the date and time of day).
9b371988
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997.next
998After the first hyphen, the next six characters are the id of the process that
168e428f 999received the message.
9b371988
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1000.next
1001There are two different possibilities for the final two characters:
1002.olist
0a4e3112 1003.oindex "&%localhost_number%&"
9b371988 1004If &%localhost_number%& is not set, this value is the fractional part of the
168e428f
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1005time of reception, normally in units of 1/2000 of a second, but for systems
1006that must use base 36 instead of base 62 (because of case-insensitive file
1007systems), the units are 1/1000 of a second.
9b371988
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1008.next
1009If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
168e428f
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1010the fractional part of the time, which in this case is in units of 1/200
1011(1/100) of a second.
9b371988
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1012.endlist
1013.endlist
168e428f
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1014
1015After a message has been received, Exim waits for the clock to tick at the
1016appropriate resolution before proceeding, so that if another message is
1017received by the same process, or by another process with the same (re-used)
1018pid, it is guaranteed that the time will be different. In most cases, the clock
1019will already have ticked while the message was being received.
1020
1021
f89d2485 1022.section "Receiving mail" "SECID13"
9b371988
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1023.cindex "receiving mail"
1024.cindex "message" "reception"
068aaea8
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1025The only way Exim can receive mail from another host is using SMTP over
1026TCP/IP, in which case the sender and recipient addresses are transferred using
168e428f
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1027SMTP commands. However, from a locally running process (such as a user's MUA),
1028there are several possibilities:
1029
9b371988
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1030.ilist
1031If the process runs Exim with the &%-bm%& option, the message is read
168e428f 1032non-interactively (usually via a pipe), with the recipients taken from the
9b371988
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1033command line, or from the body of the message if &%-t%& is also used.
1034.next
1035If the process runs Exim with the &%-bS%& option, the message is also read
168e428f
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1036non-interactively, but in this case the recipients are listed at the start of
1037the message in a series of SMTP RCPT commands, terminated by a DATA
9b371988 1038command. This is so-called &"batch SMTP"& format,
168e428f
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1039but it isn't really SMTP. The SMTP commands are just another way of passing
1040envelope addresses in a non-interactive submission.
9b371988
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1041.next
1042If the process runs Exim with the &%-bs%& option, the message is read
168e428f
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1043interactively, using the SMTP protocol. A two-way pipe is normally used for
1044passing data between the local process and the Exim process.
9b371988 1045This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
168e428f 1046example, the ACLs for SMTP commands are used for this form of submission.
9b371988
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1047.next
1048A local process may also make a TCP/IP call to the host's loopback address
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1049(127.0.0.1) or any other of its IP addresses. When receiving messages, Exim
1050does not treat the loopback address specially. It treats all such connections
1051in the same way as connections from other hosts.
9b371988 1052.endlist
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1053
1054
f89d2485 1055.cindex "message sender, constructed by Exim"
9b371988 1056.cindex "sender" "constructed by Exim"
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1057In the three cases that do not involve TCP/IP, the sender address is
1058constructed from the login name of the user that called Exim and a default
9b371988 1059qualification domain (which can be set by the &%qualify_domain%& configuration
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1060option). For local or batch SMTP, a sender address that is passed using the
1061SMTP MAIL command is ignored. However, the system administrator may allow
9b371988 1062certain users (&"trusted users"&) to specify a different sender address
168e428f 1063unconditionally, or all users to specify certain forms of different sender
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1064address. The &%-f%& option or the SMTP MAIL command is used to specify these
1065different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1066users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
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1067users to change sender addresses.
1068
1069Messages received by either of the non-interactive mechanisms are subject to
1070checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1071(either over TCP/IP, or interacting with a local process) can be checked by a
1072number of ACLs that operate at different times during the SMTP session. Either
1073individual recipients, or the entire message, can be rejected if local policy
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1074requirements are not met. The &[local_scan()]& function (see chapter
1075&<<CHAPlocalscan>>&) is run for all incoming messages.
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1076
1077Exim can be configured not to start a delivery process when a message is
1078received; this can be unconditional, or depend on the number of incoming SMTP
1079connections or the system load. In these situations, new messages wait on the
1080queue until a queue runner process picks them up. However, in standard
1081configurations under normal conditions, delivery is started as soon as a
1082message is received.
1083
1084
1085
1086
1087
f89d2485 1088.section "Handling an incoming message" "SECID14"
9b371988
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1089.cindex "spool directory" "files that hold a message"
1090.cindex "file" "how a message is held"
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1091When Exim accepts a message, it writes two files in its spool directory. The
1092first contains the envelope information, the current status of the message, and
1093the header lines, and the second contains the body of the message. The names of
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1094the two spool files consist of the message id, followed by &`-H`& for the
1095file containing the envelope and header, and &`-D`& for the data file.
168e428f 1096
9b371988 1097.cindex "spool directory" "&_input_& sub-directory"
168e428f 1098By default all these message files are held in a single directory called
9b371988 1099&_input_& inside the general Exim spool directory. Some operating systems do
c0712871 1100not perform very well if the number of files in a directory gets large; to
9b371988 1101improve performance in such cases, the &%split_spool_directory%& option can be
168e428f 1102used. This causes Exim to split up the input files into 62 sub-directories
db9452a9 1103whose names are single letters or digits. When this is done, the queue is
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1104processed one sub-directory at a time instead of all at once, which can improve
1105overall performance even when there are not enough files in each directory to
db9452a9 1106affect file system performance.
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1107
1108The envelope information consists of the address of the message's sender and
1109the addresses of the recipients. This information is entirely separate from
1110any addresses contained in the header lines. The status of the message includes
1111a list of recipients who have already received the message. The format of the
9b371988 1112first spool file is described in chapter &<<CHAPspool>>&.
168e428f 1113
9b371988 1114.cindex "rewriting" "addresses"
168e428f 1115Address rewriting that is specified in the rewrite section of the configuration
9b371988 1116(see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
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1117both in the header lines and the envelope, at the time the message is accepted.
1118If during the course of delivery additional addresses are generated (for
1119example, via aliasing), these new addresses are rewritten as soon as they are
1120generated. At the time a message is actually delivered (transported) further
1121rewriting can take place; because this is a transport option, it can be
1122different for different forms of delivery. It is also possible to specify the
1123addition or removal of certain header lines at the time the message is
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1124delivered (see chapters &<<CHAProutergeneric>>& and
1125&<<CHAPtransportgeneric>>&).
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1126
1127
1128
f89d2485 1129.section "Life of a message" "SECID15"
9b371988
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1130.cindex "message" "life of"
1131.cindex "message" "frozen"
168e428f
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1132A message remains in the spool directory until it is completely delivered to
1133its recipients or to an error address, or until it is deleted by an
1134administrator or by the user who originally created it. In cases when delivery
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1135cannot proceed &-- for example, when a message can neither be delivered to its
1136recipients nor returned to its sender, the message is marked &"frozen"& on the
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1137spool, and no more deliveries are attempted.
1138
9b371988
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1139.cindex "frozen messages" "thawing"
1140.cindex "message" "thawing frozen"
1141An administrator can &"thaw"& such messages when the problem has been
1142corrected, and can also freeze individual messages by hand if necessary. In
1143addition, an administrator can force a delivery error, causing a bounce message
1144to be sent.
1145
0a4e3112
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1146.oindex "&%timeout_frozen_after%&"
1147.oindex "&%ignore_bounce_errors_after%&"
9b371988
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1148There are options called &%ignore_bounce_errors_after%& and
1149&%timeout_frozen_after%&, which discard frozen messages after a certain time.
068aaea8 1150The first applies only to frozen bounces, the second to any frozen messages.
168e428f 1151
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1152.cindex "message" "log file for"
1153.cindex "log" "file for each message"
168e428f 1154While Exim is working on a message, it writes information about each delivery
068aaea8 1155attempt to its main log file. This includes successful, unsuccessful, and
9b371988
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1156delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1157lines are also written to a separate &'message log'& file for each message.
1158These logs are solely for the benefit of the administrator, and are normally
1159deleted along with the spool files when processing of a message is complete.
168e428f 1160The use of individual message logs can be disabled by setting
9b371988
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1161&%no_message_logs%&; this might give an improvement in performance on very busy
1162systems.
168e428f 1163
9b371988
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1164.cindex "journal file"
1165.cindex "file" "journal"
168e428f
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1166All the information Exim itself needs to set up a delivery is kept in the first
1167spool file, along with the header lines. When a successful delivery occurs, the
1168address is immediately written at the end of a journal file, whose name is the
9b371988
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1169message id followed by &`-J`&. At the end of a delivery run, if there are some
1170addresses left to be tried again later, the first spool file (the &`-H`& file)
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1171is updated to indicate which these are, and the journal file is then deleted.
1172Updating the spool file is done by writing a new file and renaming it, to
1173minimize the possibility of data loss.
1174
1175Should the system or the program crash after a successful delivery but before
1176the spool file has been updated, the journal is left lying around. The next
1177time Exim attempts to deliver the message, it reads the journal file and
1178updates the spool file before proceeding. This minimizes the chances of double
1179deliveries caused by crashes.
1180
1181
1182
9b371988
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1183.section "Processing an address for delivery" "SECTprocaddress"
1184.cindex "drivers" "definition of"
1185.cindex "router" "definition of"
1186.cindex "transport" "definition of"
1187The main delivery processing elements of Exim are called &'routers'& and
1188&'transports'&, and collectively these are known as &'drivers'&. Code for a
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1189number of them is provided in the source distribution, and compile-time options
1190specify which ones are included in the binary. Run time options specify which
1191ones are actually used for delivering messages.
1192
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1193.cindex "drivers" "instance definition"
1194Each driver that is specified in the run time configuration is an &'instance'&
168e428f 1195of that particular driver type. Multiple instances are allowed; for example,
9b371988 1196you can set up several different &(smtp)& transports, each with different
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1197option values that might specify different ports or different timeouts. Each
1198instance has its own identifying name. In what follows we will normally use the
1199instance name when discussing one particular instance (that is, one specific
1200configuration of the driver), and the generic driver name when discussing
1201the driver's features in general.
1202
9b371988 1203A &'router'& is a driver that operates on an address, either determining how
068aaea8 1204its delivery should happen, by assigning it to a specific transport, or
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1205converting the address into one or more new addresses (for example, via an
1206alias file). A router may also explicitly choose to fail an address, causing it
1207to be bounced.
1208
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1209A &'transport'& is a driver that transmits a copy of the message from Exim's
1210spool to some destination. There are two kinds of transport: for a &'local'&
168e428f 1211transport, the destination is a file or a pipe on the local host, whereas for a
9b371988 1212&'remote'& transport the destination is some other host. A message is passed
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1213to a specific transport as a result of successful routing. If a message has
1214several recipients, it may be passed to a number of different transports.
1215
9b371988 1216.cindex "preconditions" "definition of"
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1217An address is processed by passing it to each configured router instance in
1218turn, subject to certain preconditions, until a router accepts the address or
1219specifies that it should be bounced. We will describe this process in more
068aaea8
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1220detail shortly. First, as a simple example, we consider how each recipient
1221address in a message is processed in a small configuration of three routers.
168e428f 1222
068aaea8 1223To make this a more concrete example, it is described in terms of some actual
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1224routers, but remember, this is only an example. You can configure Exim's
1225routers in many different ways, and there may be any number of routers in a
1226configuration.
1227
1228The first router that is specified in a configuration is often one that handles
1229addresses in domains that are not recognized specially by the local host. These
1230are typically addresses for arbitrary domains on the Internet. A precondition
1231is set up which looks for the special domains known to the host (for example,
9b371988 1232its own domain name), and the router is run for addresses that do &'not'&
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1233match. Typically, this is a router that looks up domains in the DNS in order to
1234find the hosts to which this address routes. If it succeeds, the address is
068aaea8 1235assigned to a suitable SMTP transport; if it does not succeed, the router is
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1236configured to fail the address.
1237
068aaea8 1238The second router is reached only when the domain is recognized as one that
9b371988 1239&"belongs"& to the local host. This router does redirection &-- also known as
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1240aliasing and forwarding. When it generates one or more new addresses from the
1241original, each of them is routed independently from the start. Otherwise, the
1242router may cause an address to fail, or it may simply decline to handle the
1243address, in which case the address is passed to the next router.
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1244
1245The final router in many configurations is one that checks to see if the
1246address belongs to a local mailbox. The precondition may involve a check to
1247see if the local part is the name of a login account, or it may look up the
1248local part in a file or a database. If its preconditions are not met, or if
1249the router declines, we have reached the end of the routers. When this happens,
1250the address is bounced.
1251
1252
1253
f89d2485 1254.section "Processing an address for verification" "SECID16"
9b371988
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1255.cindex "router" "for verification"
1256.cindex "verifying address" "overview"
168e428f 1257As well as being used to decide how to deliver to an address, Exim's routers
9b371988 1258are also used for &'address verification'&. Verification can be requested as
168e428f 1259one of the checks to be performed in an ACL for incoming messages, on both
9b371988
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1260sender and recipient addresses, and it can be tested using the &%-bv%& and
1261&%-bvs%& command line options.
168e428f 1262
9b371988 1263When an address is being verified, the routers are run in &"verify mode"&. This
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1264does not affect the way the routers work, but it is a state that can be
1265detected. By this means, a router can be skipped or made to behave differently
1266when verifying. A common example is a configuration in which the first router
1267sends all messages to a message-scanning program, unless they have been
1268previously scanned. Thus, the first router accepts all addresses without any
9b371988 1269checking, making it useless for verifying. Normally, the &%no_verify%& option
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1270would be set for such a router, causing it to be skipped in verify mode.
1271
1272
1273
1274
9b371988
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1275.section "Running an individual router" "SECTrunindrou"
1276.cindex "router" "running details"
1277.cindex "preconditions" "checking"
1278.cindex "router" "result of running"
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1279As explained in the example above, a number of preconditions are checked before
1280running a router. If any are not met, the router is skipped, and the address is
9b371988 1281passed to the next router. When all the preconditions on a router &'are'& met,
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1282the router is run. What happens next depends on the outcome, which is one of
1283the following:
1284
9b371988
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1285.ilist
1286&'accept'&: The router accepts the address, and either assigns it to a
1287transport, or generates one or more &"child"& addresses. Processing the
1288original address ceases,
0a4e3112 1289.oindex "&%unseen%&"
9b371988 1290unless the &%unseen%& option is set on the router. This option
168e428f 1291can be used to set up multiple deliveries with different routing (for example,
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1292for keeping archive copies of messages). When &%unseen%& is set, the address is
1293passed to the next router. Normally, however, an &'accept'& return marks the
168e428f 1294end of routing.
9b371988 1295
068aaea8
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1296Any child addresses generated by the router are processed independently,
1297starting with the first router by default. It is possible to change this by
9b371988
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1298setting the &%redirect_router%& option to specify which router to start at for
1299child addresses. Unlike &%pass_router%& (see below) the router specified by
1300&%redirect_router%& may be anywhere in the router configuration.
1301.next
1302&'pass'&: The router recognizes the address, but cannot handle it itself. It
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1303requests that the address be passed to another router. By default the address
1304is passed to the next router, but this can be changed by setting the
9b371988 1305&%pass_router%& option. However, (unlike &%redirect_router%&) the named router
168e428f 1306must be below the current router (to avoid loops).
9b371988
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1307.next
1308&'decline'&: The router declines to accept the address because it does not
168e428f 1309recognize it at all. By default, the address is passed to the next router, but
9b371988
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1310this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1311set, all the remaining routers are skipped. In effect, &%no_more%& converts
1312&'decline'& into &'fail'&.
1313.next
1314&'fail'&: The router determines that the address should fail, and queues it for
168e428f 1315the generation of a bounce message. There is no further processing of the
9b371988
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1316original address unless &%unseen%& is set on the router.
1317.next
1318&'defer'&: The router cannot handle the address at the present time. (A
068aaea8
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1319database may be offline, or a DNS lookup may have timed out.) No further
1320processing of the address happens in this delivery attempt. It is tried again
1321next time the message is considered for delivery.
9b371988
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1322.next
1323&'error'&: There is some error in the router (for example, a syntax error in
168e428f 1324its configuration). The action is as for defer.
9b371988 1325.endlist
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1326
1327If an address reaches the end of the routers without having been accepted by
068aaea8 1328any of them, it is bounced as unrouteable. The default error message in this
9b371988
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1329situation is &"unrouteable address"&, but you can set your own message by
1330making use of the &%cannot_route_message%& option. This can be set for any
1331router; the value from the last router that &"saw"& the address is used.
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1332
1333Sometimes while routing you want to fail a delivery when some conditions are
1334met but others are not, instead of passing the address on for further routing.
1335You can do this by having a second router that explicitly fails the delivery
9b371988 1336when the relevant conditions are met. The &(redirect)& router has a &"fail"&
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1337facility for this purpose.
1338
1339
f89d2485 1340.section "Duplicate addresses" "SECID17"
9b371988 1341.cindex "case of local parts"
f89d2485 1342.cindex "address duplicate, discarding"
db9452a9 1343.cindex "duplicate addresses"
068aaea8
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1344Once routing is complete, Exim scans the addresses that are assigned to local
1345and remote transports, and discards any duplicates that it finds. During this
3cb1b51e 1346check, local parts are treated as case-sensitive. This happens only when
db9452a9 1347actually delivering a message; when testing routers with &%-bt%&, all the
3cb1b51e 1348routed addresses are shown.
db9452a9 1349
068aaea8 1350
168e428f 1351
9b371988 1352.section "Router preconditions" "SECTrouprecon"
f89d2485 1353.cindex "router" "preconditions, order of processing"
9b371988 1354.cindex "preconditions" "order of processing"
168e428f
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1355The preconditions that are tested for each router are listed below, in the
1356order in which they are tested. The individual configuration options are
9b371988 1357described in more detail in chapter &<<CHAProutergeneric>>&.
168e428f 1358
9b371988
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1359.ilist
1360The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
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1361the local parts handled by the router may or must have certain prefixes and/or
1362suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1363skipped. These conditions are tested first. When an affix is present, it is
1364removed from the local part before further processing, including the evaluation
1365of any other conditions.
9b371988
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1366.next
1367Routers can be designated for use only when not verifying an address, that is,
168e428f 1368only when routing it for delivery (or testing its delivery routing). If the
9b371988 1369&%verify%& option is set false, the router is skipped when Exim is verifying an
168e428f 1370address.
9b371988
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1371Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1372&%verify_recipient%&, which independently control the use of the router for
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1373sender and recipient verification. You can set these options directly if
1374you want a router to be used for only one type of verification.
5b0cf788
JH
1375Note that cutthrough delivery is classed as a recipient verification
1376for this purpose.
9b371988
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1377.next
1378If the &%address_test%& option is set false, the router is skipped when Exim is
1379run with the &%-bt%& option to test an address routing. This can be helpful
1380when the first router sends all new messages to a scanner of some sort; it
1381makes it possible to use &%-bt%& to test subsequent delivery routing without
1382having to simulate the effect of the scanner.
1383.next
1384Routers can be designated for use only when verifying an address, as
1385opposed to routing it for delivery. The &%verify_only%& option controls this.
5b0cf788 1386Again, cutthrough delibery counts as a verification.
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1387.next
1388Individual routers can be explicitly skipped when running the routers to
1389check an address given in the SMTP EXPN command (see the &%expn%& option).
1390.next
1391If the &%domains%& option is set, the domain of the address must be in the set
068aaea8 1392of domains that it defines.
9b371988 1393.next
f89d2485
PH
1394.vindex "&$local_part_prefix$&"
1395.vindex "&$local_part$&"
1396.vindex "&$local_part_suffix$&"
9b371988
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1397If the &%local_parts%& option is set, the local part of the address must be in
1398the set of local parts that it defines. If &%local_part_prefix%& or
1399&%local_part_suffix%& is in use, the prefix or suffix is removed from the local
168e428f 1400part before this check. If you want to do precondition tests on local parts
9b371988
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1401that include affixes, you can do so by using a &%condition%& option (see below)
1402that uses the variables &$local_part$&, &$local_part_prefix$&, and
1403&$local_part_suffix$& as necessary.
1404.next
f89d2485
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1405.vindex "&$local_user_uid$&"
1406.vindex "&$local_user_gid$&"
1407.vindex "&$home$&"
9b371988 1408If the &%check_local_user%& option is set, the local part must be the name of
068aaea8 1409an account on the local host. If this check succeeds, the uid and gid of the
9b371988
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1410local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1411user's home directory is placed in &$home$&; these values can be used in the
1412remaining preconditions.
1413.next
1414If the &%router_home_directory%& option is set, it is expanded at this point,
1415because it overrides the value of &$home$&. If this expansion were left till
1416later, the value of &$home$& as set by &%check_local_user%& would be used in
1417subsequent tests. Having two different values of &$home$& in the same router
168e428f 1418could lead to confusion.
9b371988
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1419.next
1420If the &%senders%& option is set, the envelope sender address must be in the
1421set of addresses that it defines.
1422.next
1423If the &%require_files%& option is set, the existence or non-existence of
168e428f 1424specified files is tested.
9b371988
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1425.next
1426.cindex "customizing" "precondition"
1427If the &%condition%& option is set, it is evaluated and tested. This option
1428uses an expanded string to allow you to set up your own custom preconditions.
1429Expanded strings are described in chapter &<<CHAPexpand>>&.
1430.endlist
168e428f 1431
168e428f 1432
9b371988
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1433Note that &%require_files%& comes near the end of the list, so you cannot use
1434it to check for the existence of a file in which to lookup up a domain, local
168e428f 1435part, or sender. However, as these options are all expanded, you can use the
9b371988
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1436&%exists%& expansion condition to make such tests within each condition. The
1437&%require_files%& option is intended for checking files that the router may be
168e428f 1438going to use internally, or which are needed by a specific transport (for
9b371988 1439example, &_.procmailrc_&).
168e428f
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1440
1441
1442
f89d2485 1443.section "Delivery in detail" "SECID18"
9b371988 1444.cindex "delivery" "in detail"
168e428f
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1445When a message is to be delivered, the sequence of events is as follows:
1446
9b371988
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1447.ilist
1448If a system-wide filter file is specified, the message is passed to it. The
168e428f
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1449filter may add recipients to the message, replace the recipients, discard the
1450message, cause a new message to be generated, or cause the message delivery to
1451fail. The format of the system filter file is the same as for Exim user filter
9b371988
PH
1452files, described in the separate document entitled &'Exim's interfaces to mail
1453filtering'&.
1454.cindex "Sieve filter" "not available for system filter"
1455(&*Note*&: Sieve cannot be used for system filter files.)
1456
1457Some additional features are available in system filters &-- see chapter
1458&<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
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1459filter only once per delivery attempt, however many recipients it has. However,
1460if there are several delivery attempts because one or more addresses could not
1461be immediately delivered, the system filter is run each time. The filter
9b371988 1462condition &%first_delivery%& can be used to detect the first run of the system
168e428f 1463filter.
9b371988
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1464.next
1465Each recipient address is offered to each configured router in turn, subject to
1466its preconditions, until one is able to handle it. If no router can handle the
1467address, that is, if they all decline, the address is failed. Because routers
1468can be targeted at particular domains, several locally handled domains can be
1469processed entirely independently of each other.
1470.next
1471.cindex "routing" "loops in"
1472.cindex "loop" "while routing"
1473A router that accepts an address may assign it to a local or a remote
1474transport. However, the transport is not run at this time. Instead, the address
1475is placed on a list for the particular transport, which will be run later.
068aaea8
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1476Alternatively, the router may generate one or more new addresses (typically
1477from alias, forward, or filter files). New addresses are fed back into this
1478process from the top, but in order to avoid loops, a router ignores any address
1479which has an identically-named ancestor that was processed by itself.
9b371988
PH
1480.next
1481When all the routing has been done, addresses that have been successfully
168e428f
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1482handled are passed to their assigned transports. When local transports are
1483doing real local deliveries, they handle only one address at a time, but if a
1484local transport is being used as a pseudo-remote transport (for example, to
1485collect batched SMTP messages for transmission by some other means) multiple
1486addresses can be handled. Remote transports can always handle more than one
1487address at a time, but can be configured not to do so, or to restrict multiple
1488addresses to the same domain.
9b371988
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1489.next
1490Each local delivery to a file or a pipe runs in a separate process under a
168e428f
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1491non-privileged uid, and these deliveries are run one at a time. Remote
1492deliveries also run in separate processes, normally under a uid that is private
9b371988 1493to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
168e428f 1494run in parallel. The maximum number of simultaneous remote deliveries for any
9b371988 1495one message is set by the &%remote_max_parallel%& option.
168e428f
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1496The order in which deliveries are done is not defined, except that all local
1497deliveries happen before any remote deliveries.
9b371988
PH
1498.next
1499.cindex "queue runner"
168e428f
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1500When it encounters a local delivery during a queue run, Exim checks its retry
1501database to see if there has been a previous temporary delivery failure for the
1502address before running the local transport. If there was a previous failure,
1503Exim does not attempt a new delivery until the retry time for the address is
1504reached. However, this happens only for delivery attempts that are part of a
1505queue run. Local deliveries are always attempted when delivery immediately
1506follows message reception, even if retry times are set for them. This makes for
1507better behaviour if one particular message is causing problems (for example,
1508causing quota overflow, or provoking an error in a filter file).
9b371988
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1509.next
1510.cindex "delivery" "retry in remote transports"
168e428f
PH
1511Remote transports do their own retry handling, since an address may be
1512deliverable to one of a number of hosts, each of which may have a different
1513retry time. If there have been previous temporary failures and no host has
1514reached its retry time, no delivery is attempted, whether in a queue run or
9b371988
PH
1515not. See chapter &<<CHAPretry>>& for details of retry strategies.
1516.next
1517If there were any permanent errors, a bounce message is returned to an
168e428f
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1518appropriate address (the sender in the common case), with details of the error
1519for each failing address. Exim can be configured to send copies of bounce
1520messages to other addresses.
9b371988
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1521.next
1522.cindex "delivery" "deferral"
168e428f
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1523If one or more addresses suffered a temporary failure, the message is left on
1524the queue, to be tried again later. Delivery of these addresses is said to be
9b371988
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1525&'deferred'&.
1526.next
1527When all the recipient addresses have either been delivered or bounced,
168e428f
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1528handling of the message is complete. The spool files and message log are
1529deleted, though the message log can optionally be preserved if required.
9b371988 1530.endlist
168e428f
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1531
1532
1533
1534
f89d2485 1535.section "Retry mechanism" "SECID19"
9b371988
PH
1536.cindex "delivery" "retry mechanism"
1537.cindex "retry" "description of mechanism"
1538.cindex "queue runner"
168e428f
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1539Exim's mechanism for retrying messages that fail to get delivered at the first
1540attempt is the queue runner process. You must either run an Exim daemon that
9b371988
PH
1541uses the &%-q%& option with a time interval to start queue runners at regular
1542intervals, or use some other means (such as &'cron'&) to start them. If you do
168e428f
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1543not arrange for queue runners to be run, messages that fail temporarily at the
1544first attempt will remain on your queue for ever. A queue runner process works
068aaea8 1545its way through the queue, one message at a time, trying each delivery that has
168e428f
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1546passed its retry time.
1547You can run several queue runners at once.
1548
1549Exim uses a set of configured rules to determine when next to retry the failing
9b371988
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1550address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1551should give up trying to deliver to the address, at which point it generates a
1552bounce message. If no retry rules are set for a particular host, address, and
1553error combination, no retries are attempted, and temporary errors are treated
1554as permanent.
168e428f
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1555
1556
1557
f89d2485 1558.section "Temporary delivery failure" "SECID20"
9b371988 1559.cindex "delivery" "temporary failure"
168e428f
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1560There are many reasons why a message may not be immediately deliverable to a
1561particular address. Failure to connect to a remote machine (because it, or the
1562connection to it, is down) is one of the most common. Temporary failures may be
1563detected during routing as well as during the transport stage of delivery.
1564Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1565is on a file system where the user is over quota. Exim can be configured to
1566impose its own quotas on local mailboxes; where system quotas are set they will
1567also apply.
1568
1569If a host is unreachable for a period of time, a number of messages may be
1570waiting for it by the time it recovers, and sending them in a single SMTP
1571connection is clearly beneficial. Whenever a delivery to a remote host is
1572deferred,
9b371988 1573.cindex "hints database"
168e428f
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1574Exim makes a note in its hints database, and whenever a successful
1575SMTP delivery has happened, it looks to see if any other messages are waiting
1576for the same host. If any are found, they are sent over the same SMTP
1577connection, subject to a configuration limit as to the maximum number in any
1578one connection.
168e428f
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1579
1580
1581
f89d2485 1582.section "Permanent delivery failure" "SECID21"
9b371988
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1583.cindex "delivery" "permanent failure"
1584.cindex "bounce message" "when generated"
168e428f
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1585When a message cannot be delivered to some or all of its intended recipients, a
1586bounce message is generated. Temporary delivery failures turn into permanent
1587errors when their timeout expires. All the addresses that fail in a given
1588delivery attempt are listed in a single message. If the original message has
1589many recipients, it is possible for some addresses to fail in one delivery
1590attempt and others to fail subsequently, giving rise to more than one bounce
1591message. The wording of bounce messages can be customized by the administrator.
9b371988 1592See chapter &<<CHAPemsgcust>>& for details.
168e428f 1593
9b371988
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1594.cindex "&'X-Failed-Recipients:'& header line"
1595Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
168e428f
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1596failed addresses, for the benefit of programs that try to analyse such messages
1597automatically.
1598
9b371988 1599.cindex "bounce message" "recipient of"
168e428f
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1600A bounce message is normally sent to the sender of the original message, as
1601obtained from the message's envelope. For incoming SMTP messages, this is the
9b371988
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1602address given in the MAIL command. However, when an address is expanded via a
1603forward or alias file, an alternative address can be specified for delivery
1604failures of the generated addresses. For a mailing list expansion (see section
1605&<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1606of the list.
168e428f
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1607
1608
1609
f89d2485 1610.section "Failures to deliver bounce messages" "SECID22"
9b371988 1611.cindex "bounce message" "failure to deliver"
168e428f
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1612If a bounce message (either locally generated or received from a remote host)
1613itself suffers a permanent delivery failure, the message is left on the queue,
1614but it is frozen, awaiting the attention of an administrator. There are options
068aaea8 1615that can be used to make Exim discard such failed messages, or to keep them
9b371988
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1616for only a short time (see &%timeout_frozen_after%& and
1617&%ignore_bounce_errors_after%&).
168e428f
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1618
1619
1620
1621
1622
9b371988
PH
1623. ////////////////////////////////////////////////////////////////////////////
1624. ////////////////////////////////////////////////////////////////////////////
168e428f 1625
f89d2485 1626.chapter "Building and installing Exim" "CHID3"
4f578862 1627.scindex IIDbuex "building Exim"
168e428f 1628
f89d2485
PH
1629.section "Unpacking" "SECID23"
1630Exim is distributed as a gzipped or bzipped tar file which, when unpacked,
168e428f 1631creates a directory with the name of the current release (for example,
2aee48d6 1632&_exim-&version()_&) into which the following files are placed:
9b371988
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1633
1634.table2 140pt
f89d2485
PH
1635.irow &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1636.irow &_CHANGES_& "contains a reference to where changes are &&&
1637 documented"
1638.irow &_LICENCE_& "the GNU General Public Licence"
1639.irow &_Makefile_& "top-level make file"
1640.irow &_NOTICE_& "conditions for the use of Exim"
1641.irow &_README_& "list of files, directories and simple build &&&
1642 instructions"
9b371988
PH
1643.endtable
1644
1645Other files whose names begin with &_README_& may also be present. The
168e428f
PH
1646following subdirectories are created:
1647
9b371988 1648.table2 140pt
f89d2485
PH
1649.irow &_Local_& "an empty directory for local configuration files"
1650.irow &_OS_& "OS-specific files"
1651.irow &_doc_& "documentation files"
1652.irow &_exim_monitor_& "source files for the Exim monitor"
1653.irow &_scripts_& "scripts used in the build process"
1654.irow &_src_& "remaining source files"
1655.irow &_util_& "independent utilities"
9b371988
PH
1656.endtable
1657
1658The main utility programs are contained in the &_src_& directory, and are built
1659with the Exim binary. The &_util_& directory contains a few optional scripts
168e428f
PH
1660that may be useful to some sites.
1661
1662
f89d2485 1663.section "Multiple machine architectures and operating systems" "SECID24"
9b371988 1664.cindex "building Exim" "multiple OS/architectures"
168e428f
PH
1665The building process for Exim is arranged to make it easy to build binaries for
1666a number of different architectures and operating systems from the same set of
9b371988
PH
1667source files. Compilation does not take place in the &_src_& directory.
1668Instead, a &'build directory'& is created for each architecture and operating
1669system.
1670.cindex "symbolic link" "to build directory"
168e428f 1671Symbolic links to the sources are installed in this directory, which is where
9b371988
PH
1672the actual building takes place. In most cases, Exim can discover the machine
1673architecture and operating system for itself, but the defaults can be
1674overridden if necessary.
168e428f 1675
168e428f 1676
8473d4ee 1677.section "PCRE library" "SECTpcre"
210f147e
NM
1678.cindex "PCRE library"
1679Exim no longer has an embedded PCRE library as the vast majority of
1680modern systems include PCRE as a system library, although you may need
1681to install the PCRE or PCRE development package for your operating
1682system. If your system has a normal PCRE installation the Exim build
1683process will need no further configuration. If the library or the
6a6084f8
PP
1684headers are in an unusual location you will need to either set the PCRE_LIBS
1685and INCLUDE directives appropriately,
1686or set PCRE_CONFIG=yes to use the installed &(pcre-config)& command.
1687If your operating system has no
210f147e
NM
1688PCRE support then you will need to obtain and build the current PCRE
1689from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/).
6a6084f8 1690More information on PCRE is available at &url(http://www.pcre.org/).
210f147e 1691
9b371988
PH
1692.section "DBM libraries" "SECTdb"
1693.cindex "DBM libraries" "discussion of"
1694.cindex "hints database" "DBM files used for"
168e428f
PH
1695Even if you do not use any DBM files in your configuration, Exim still needs a
1696DBM library in order to operate, because it uses indexed files for its hints
1697databases. Unfortunately, there are a number of DBM libraries in existence, and
1698different operating systems often have different ones installed.
1699
9b371988 1700.cindex "Solaris" "DBM library for"
f89d2485
PH
1701.cindex "IRIX, DBM library for"
1702.cindex "BSD, DBM library for"
1703.cindex "Linux, DBM library for"
168e428f
PH
1704If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1705Linux distribution, the DBM configuration should happen automatically, and you
1706may be able to ignore this section. Otherwise, you may have to learn more than
1707you would like about DBM libraries from what follows.
1708
9b371988 1709.cindex "&'ndbm'& DBM library"
168e428f 1710Licensed versions of Unix normally contain a library of DBM functions operating
9b371988 1711via the &'ndbm'& interface, and this is what Exim expects by default. Free
168e428f
PH
1712versions of Unix seem to vary in what they contain as standard. In particular,
1713some early versions of Linux have no default DBM library, and different
1714distributors have chosen to bundle different libraries with their packaged
f89d2485 1715versions. However, the more recent releases seem to have standardized on the
168e428f
PH
1716Berkeley DB library.
1717
1718Different DBM libraries have different conventions for naming the files they
9b371988 1719use. When a program opens a file called &_dbmfile_&, there are several
168e428f
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1720possibilities:
1721
9b371988
PH
1722.olist
1723A traditional &'ndbm'& implementation, such as that supplied as part of
1724Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1725.next
1726.cindex "&'gdbm'& DBM library"
1727The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
168e428f 1728compatibility interface it makes two different hard links to it with names
9b371988 1729&_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
168e428f 1730file name is used unmodified.
9b371988
PH
1731.next
1732.cindex "Berkeley DB library"
1733The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1734operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1735programmer exactly the same as the traditional &'ndbm'& implementation.
1736.next
1737If the Berkeley package is used in its native mode, it operates on a single
1738file called &_dbmfile_&; the programmer's interface is somewhat different to
1739the traditional &'ndbm'& interface.
1740.next
1741To complicate things further, there are several very different versions of the
168e428f 1742Berkeley DB package. Version 1.85 was stable for a very long time, releases
9b371988
PH
17432.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1744numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
168e428f 1745versions of Berkeley DB can be obtained from
9b371988
PH
1746&url(http://www.sleepycat.com/).
1747.next
1748.cindex "&'tdb'& DBM library"
1749Yet another DBM library, called &'tdb'&, is available from
1750&url(http://download.sourceforge.net/tdb). It has its own interface, and also
1751operates on a single file.
1752.endlist
1753
1754.cindex "USE_DB"
1755.cindex "DBM libraries" "configuration for building"
168e428f
PH
1756Exim and its utilities can be compiled to use any of these interfaces. In order
1757to use any version of the Berkeley DB package in native mode, you must set
1758USE_DB in an appropriate configuration file (typically
9b371988
PH
1759&_Local/Makefile_&). For example:
1760.code
1761USE_DB=yes
1762.endd
168e428f
PH
1763Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1764error is diagnosed if you set more than one of these.
1765
1766At the lowest level, the build-time configuration sets none of these options,
1767thereby assuming an interface of type (1). However, some operating system
1768configuration files (for example, those for the BSD operating systems and
1769Linux) assume type (4) by setting USE_DB as their default, and the
1770configuration files for Cygwin set USE_GDBM. Anything you set in
9b371988 1771&_Local/Makefile_&, however, overrides these system defaults.
168e428f
PH
1772
1773As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1774necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1775in one of these lines:
9b371988
PH
1776.code
1777DBMLIB = -ldb
1778DBMLIB = -ltdb
1779.endd
168e428f
PH
1780Settings like that will work if the DBM library is installed in the standard
1781place. Sometimes it is not, and the library's header file may also not be in
1782the default path. You may need to set INCLUDE to specify where the header
1783file is, and to specify the path to the library more fully in DBMLIB, as in
1784this example:
9b371988
PH
1785.code
1786INCLUDE=-I/usr/local/include/db-4.1
1787DBMLIB=/usr/local/lib/db-4.1/libdb.a
1788.endd
168e428f 1789There is further detailed discussion about the various DBM libraries in the
9b371988 1790file &_doc/dbm.discuss.txt_& in the Exim distribution.
168e428f
PH
1791
1792
1793
f89d2485 1794.section "Pre-building configuration" "SECID25"
9b371988
PH
1795.cindex "building Exim" "pre-building configuration"
1796.cindex "configuration for building Exim"
1797.cindex "&_Local/Makefile_&"
1798.cindex "&_src/EDITME_&"
168e428f
PH
1799Before building Exim, a local configuration file that specifies options
1800independent of any operating system has to be created with the name
9b371988
PH
1801&_Local/Makefile_&. A template for this file is supplied as the file
1802&_src/EDITME_&, and it contains full descriptions of all the option settings
168e428f
PH
1803therein. These descriptions are therefore not repeated here. If you are
1804building Exim for the first time, the simplest thing to do is to copy
9b371988 1805&_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
168e428f
PH
1806
1807There are three settings that you must supply, because Exim will not build
1808without them. They are the location of the run time configuration file
1809(CONFIGURE_FILE), the directory in which Exim binaries will be installed
1810(BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1811maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1812a colon-separated list of file names; Exim uses the first of them that exists.
1813
1814There are a few other parameters that can be specified either at build time or
1815at run time, to enable the same binary to be used on a number of different
1816machines. However, if the locations of Exim's spool directory and log file
1817directory (if not within the spool directory) are fixed, it is recommended that
9b371988 1818you specify them in &_Local/Makefile_& instead of at run time, so that errors
168e428f
PH
1819detected early in Exim's execution (such as a malformed configuration file) can
1820be logged.
1821
9b371988 1822.cindex "content scanning" "specifying at build time"
068aaea8 1823Exim's interfaces for calling virus and spam scanning software directly from
168e428f
PH
1824access control lists are not compiled by default. If you want to include these
1825facilities, you need to set
9b371988
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1826.code
1827WITH_CONTENT_SCAN=yes
1828.endd
1829in your &_Local/Makefile_&. For details of the facilities themselves, see
1830chapter &<<CHAPexiscan>>&.
168e428f
PH
1831
1832
9b371988 1833.cindex "&_Local/eximon.conf_&"
3cb1b51e 1834.cindex "&_exim_monitor/EDITME_&"
168e428f 1835If you are going to build the Exim monitor, a similar configuration process is
9b371988
PH
1836required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1837your installation and saved under the name &_Local/eximon.conf_&. If you are
1838happy with the default settings described in &_exim_monitor/EDITME_&,
1839&_Local/eximon.conf_& can be empty, but it must exist.
168e428f
PH
1840
1841This is all the configuration that is needed in straightforward cases for known
1842operating systems. However, the building process is set up so that it is easy
1843to override options that are set by default or by operating-system-specific
1844configuration files, for example to change the name of the C compiler, which
9b371988
PH
1845defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1846do this.
168e428f
PH
1847
1848
1849
f89d2485 1850.section "Support for iconv()" "SECID26"
9b371988
PH
1851.cindex "&[iconv()]& support"
1852.cindex "RFC 2047"
168e428f
PH
1853The contents of header lines in messages may be encoded according to the rules
1854described RFC 2047. This makes it possible to transmit characters that are not
1855in the ASCII character set, and to label them as being in a particular
9b371988 1856character set. When Exim is inspecting header lines by means of the &%$h_%&
168e428f
PH
1857mechanism, it decodes them, and translates them into a specified character set
1858(default ISO-8859-1). The translation is possible only if the operating system
9b371988
PH
1859supports the &[iconv()]& function.
1860
1861However, some of the operating systems that supply &[iconv()]& do not support
1862very many conversions. The GNU &%libiconv%& library (available from
1863&url(http://www.gnu.org/software/libiconv/)) can be installed on such
1864systems to remedy this deficiency, as well as on systems that do not supply
1865&[iconv()]& at all. After installing &%libiconv%&, you should add
1866.code
1867HAVE_ICONV=yes
1868.endd
1869to your &_Local/Makefile_& and rebuild Exim.
1870
1871
1872
1873.section "Including TLS/SSL encryption support" "SECTinctlsssl"
1874.cindex "TLS" "including support for TLS"
1875.cindex "encryption" "including support for"
1876.cindex "SUPPORT_TLS"
1877.cindex "OpenSSL" "building Exim with"
1878.cindex "GnuTLS" "building Exim with"
168e428f
PH
1879Exim can be built to support encrypted SMTP connections, using the STARTTLS
1880command as per RFC 2487. It can also support legacy clients that expect to
1881start a TLS session immediately on connection to a non-standard port (see the
9b371988 1882&%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
168e428f
PH
1883line option).
1884
1885If you want to build Exim with TLS support, you must first install either the
1886OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1887implementing SSL.
1888
1889If OpenSSL is installed, you should set
9b371988
PH
1890.code
1891SUPPORT_TLS=yes
1892TLS_LIBS=-lssl -lcrypto
1893.endd
1894in &_Local/Makefile_&. You may also need to specify the locations of the
168e428f 1895OpenSSL library and include files. For example:
9b371988
PH
1896.code
1897SUPPORT_TLS=yes
1898TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1899TLS_INCLUDE=-I/usr/local/openssl/include/
1900.endd
7e6a8985
PP
1901.cindex "pkg-config" "OpenSSL"
1902If you have &'pkg-config'& available, then instead you can just use:
1903.code
1904SUPPORT_TLS=yes
1905USE_OPENSSL_PC=openssl
1906.endd
9b371988 1907.cindex "USE_GNUTLS"
168e428f 1908If GnuTLS is installed, you should set
9b371988
PH
1909.code
1910SUPPORT_TLS=yes
1911USE_GNUTLS=yes
1912TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1913.endd
1914in &_Local/Makefile_&, and again you may need to specify the locations of the
168e428f 1915library and include files. For example:
9b371988
PH
1916.code
1917SUPPORT_TLS=yes
1918USE_GNUTLS=yes
1919TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1920TLS_INCLUDE=-I/usr/gnu/include
1921.endd
7e6a8985
PP
1922.cindex "pkg-config" "GnuTLS"
1923If you have &'pkg-config'& available, then instead you can just use:
1924.code
1925SUPPORT_TLS=yes
1926USE_GNUTLS=yes
1927USE_GNUTLS_PC=gnutls
1928.endd
7e6a8985 1929
168e428f 1930You do not need to set TLS_INCLUDE if the relevant directory is already
9b371988
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1931specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1932given in chapter &<<CHAPTLS>>&.
168e428f
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1933
1934
1935
1936
b52ed2b3
NM
1937.section "Use of tcpwrappers" "SECID27"
1938
f89d2485 1939.cindex "tcpwrappers, building Exim to support"
9b371988 1940.cindex "USE_TCP_WRAPPERS"
5dc43717
JJ
1941.cindex "TCP_WRAPPERS_DAEMON_NAME"
1942.cindex "tcp_wrappers_daemon_name"
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1943Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1944SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
168e428f 1945alternative to Exim's own checking facilities for installations that are
9b371988
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1946already making use of &'tcpwrappers'& for other purposes. To do this, you
1947should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1948&_tcpd.h_& to be available at compile time, and also ensure that the library
1949&_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1950EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1951you might have
1952.code
1953USE_TCP_WRAPPERS=yes
1954CFLAGS=-O -I/usr/local/include
1955EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1956.endd
5dc43717
JJ
1957in &_Local/Makefile_&. The daemon name to use in the &'tcpwrappers'& control
1958files is &"exim"&. For example, the line
9b371988
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1959.code
1960exim : LOCAL 192.168.1. .friendly.domain.example
1961.endd
1962in your &_/etc/hosts.allow_& file allows connections from the local host, from
1963the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&.
5dc43717
JJ
1964All other connections are denied. The daemon name used by &'tcpwrappers'&
1965can be changed at build time by setting TCP_WRAPPERS_DAEMON_NAME in
a543079f 1966&_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the
5dc43717 1967configure file. Consult the &'tcpwrappers'& documentation for
168e428f 1968further details.
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1969
1970
f89d2485 1971.section "Including support for IPv6" "SECID28"
9b371988 1972.cindex "IPv6" "including support for"
168e428f 1973Exim contains code for use on systems that have IPv6 support. Setting
9b371988 1974&`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
168e428f
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1975it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1976where the IPv6 support is not fully integrated into the normal include and
1977library files.
1978
1979Two different types of DNS record for handling IPv6 addresses have been
f89d2485 1980defined. AAAA records (analogous to A records for IPv4) are in use, and are
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1981currently seen as the mainstream. Another record type called A6 was proposed
1982as better than AAAA because it had more flexibility. However, it was felt to be
9b371988 1983over-complex, and its status was reduced to &"experimental"&. It is not known
168e428f 1984if anyone is actually using A6 records. Exim has support for A6 records, but
9b371988 1985this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
168e428f
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1986support has not been tested for some time.
1987
1988
1989
0a349494
PP
1990.section "Dynamically loaded lookup module support" "SECTdynamicmodules"
1991.cindex "lookup modules"
1992.cindex "dynamic modules"
1993.cindex ".so building"
1994On some platforms, Exim supports not compiling all lookup types directly into
1995the main binary, instead putting some into external modules which can be loaded
1996on demand.
1997This permits packagers to build Exim with support for lookups with extensive
1998library dependencies without requiring all users to install all of those
1999dependencies.
2000Most, but not all, lookup types can be built this way.
2001
2002Set &`LOOKUP_MODULE_DIR`& to the directory into which the modules will be
2003installed; Exim will only load modules from that directory, as a security
2004measure. You will need to set &`CFLAGS_DYNAMIC`& if not already defined
2005for your OS; see &_OS/Makefile-Linux_& for an example.
2006Some other requirements for adjusting &`EXTRALIBS`& may also be necessary,
2007see &_src/EDITME_& for details.
2008
2009Then, for each module to be loaded dynamically, define the relevant
2010&`LOOKUP_`&<&'lookup_type'&> flags to have the value "2" instead of "yes".
2011For example, this will build in lsearch but load sqlite and mysql support
2012on demand:
2013.code
2014LOOKUP_LSEARCH=yes
2015LOOKUP_SQLITE=2
2016LOOKUP_MYSQL=2
2017.endd
5d758a46 2018
0a349494 2019
f89d2485 2020.section "The building process" "SECID29"
9b371988
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2021.cindex "build directory"
2022Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
2023created, run &'make'& at the top level. It determines the architecture and
168e428f
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2024operating system types, and creates a build directory if one does not exist.
2025For example, on a Sun system running Solaris 8, the directory
9b371988
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2026&_build-SunOS5-5.8-sparc_& is created.
2027.cindex "symbolic link" "to source files"
168e428f
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2028Symbolic links to relevant source files are installed in the build directory.
2029
9b371988 2030&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
168e428f
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2031building process fails if it is set.
2032
9b371988 2033If this is the first time &'make'& has been run, it calls a script that builds
168e428f 2034a make file inside the build directory, using the configuration files from the
9b371988
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2035&_Local_& directory. The new make file is then passed to another instance of
2036&'make'&. This does the real work, building a number of utility scripts, and
168e428f 2037then compiling and linking the binaries for the Exim monitor (if configured), a
9b371988
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2038number of utility programs, and finally Exim itself. The command &`make
2039makefile`& can be used to force a rebuild of the make file in the build
168e428f
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2040directory, should this ever be necessary.
2041
2042If you have problems building Exim, check for any comments there may be in the
9b371988 2043&_README_& file concerning your operating system, and also take a look at the
168e428f
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2044FAQ, where some common problems are covered.
2045
2046
2047
f89d2485 2048.section 'Output from &"make"&' "SECID283"
9b371988 2049The output produced by the &'make'& process for compile lines is often very
068aaea8
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2050unreadable, because these lines can be very long. For this reason, the normal
2051output is suppressed by default, and instead output similar to that which
2052appears when compiling the 2.6 Linux kernel is generated: just a short line for
2053each module that is being compiled or linked. However, it is still possible to
9b371988
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2054get the full output, by calling &'make'& like this:
2055.code
2056FULLECHO='' make -e
2057.endd
2058The value of FULLECHO defaults to &"@"&, the flag character that suppresses
2059command reflection in &'make'&. When you ask for the full output, it is
3cb1b51e 2060given in addition to the short output.
068aaea8
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2061
2062
2063
9b371988 2064.section "Overriding build-time options for Exim" "SECToverride"
f89d2485 2065.cindex "build-time options, overriding"
168e428f
PH
2066The main make file that is created at the beginning of the building process
2067consists of the concatenation of a number of files which set configuration
9b371988 2068values, followed by a fixed set of &'make'& instructions. If a value is set
168e428f
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2069more than once, the last setting overrides any previous ones. This provides a
2070convenient way of overriding defaults. The files that are concatenated are, in
2071order:
9b371988
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2072.display
2073&_OS/Makefile-Default_&
2074&_OS/Makefile-_&<&'ostype'&>
2075&_Local/Makefile_&
2076&_Local/Makefile-_&<&'ostype'&>
2077&_Local/Makefile-_&<&'archtype'&>
2078&_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
2079&_OS/Makefile-Base_&
2080.endd
2081.cindex "&_Local/Makefile_&"
2082.cindex "building Exim" "operating system type"
2083.cindex "building Exim" "architecture type"
2084where <&'ostype'&> is the operating system type and <&'archtype'&> is the
2085architecture type. &_Local/Makefile_& is required to exist, and the building
2086process fails if it is absent. The other three &_Local_& files are optional,
168e428f
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2087and are often not needed.
2088
9b371988
PH
2089The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
2090called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
168e428f
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2091the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
2092values are used, thereby providing a means of forcing particular settings.
9b371988 2093Otherwise, the scripts try to get values from the &%uname%& command. If this
168e428f 2094fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
9b371988 2095of &'ad hoc'& transformations are then applied, to produce the standard names
168e428f
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2096that Exim expects. You can run these scripts directly from the shell in order
2097to find out what values are being used on your system.
2098
2099
9b371988 2100&_OS/Makefile-Default_& contains comments about the variables that are set
168e428f
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2101therein. Some (but not all) are mentioned below. If there is something that
2102needs changing, review the contents of this file and the contents of the make
9b371988 2103file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
168e428f
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2104default values are.
2105
2106
9b371988
PH
2107.cindex "building Exim" "overriding default settings"
2108If you need to change any of the values that are set in &_OS/Makefile-Default_&
2109or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
168e428f 2110need to change the original files. Instead, you should make the changes by
9b371988
PH
2111putting the new values in an appropriate &_Local_& file. For example,
2112.cindex "Tru64-Unix build-time settings"
168e428f
PH
2113when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2114formerly DEC-OSF1) operating system, it is necessary to specify that the C
9b371988
PH
2115compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2116called with the option &%-std1%&, to make it recognize some of the features of
168e428f 2117Standard C that Exim uses. (Most other compilers recognize Standard C by
9b371988 2118default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
168e428f 2119containing the lines
9b371988
PH
2120.code
2121CC=cc
2122CFLAGS=-std1
2123.endd
168e428f 2124If you are compiling for just one operating system, it may be easier to put
9b371988 2125these lines directly into &_Local/Makefile_&.
168e428f
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2126
2127Keeping all your local configuration settings separate from the distributed
2128files makes it easy to transfer them to new versions of Exim simply by copying
9b371988 2129the contents of the &_Local_& directory.
168e428f
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2130
2131
9b371988
PH
2132.cindex "NIS lookup type" "including support for"
2133.cindex "NIS+ lookup type" "including support for"
2134.cindex "LDAP" "including support for"
2135.cindex "lookup" "inclusion in binary"
168e428f
PH
2136Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2137lookup, but not all systems have these components installed, so the default is
2138not to include the relevant code in the binary. All the different kinds of file
2139and database lookup that Exim supports are implemented as separate code modules
2140which are included only if the relevant compile-time options are set. In the
9b371988
PH
2141case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2142.code
2143LOOKUP_LDAP=yes
2144LOOKUP_NIS=yes
2145LOOKUP_NISPLUS=yes
2146.endd
168e428f 2147and similar settings apply to the other lookup types. They are all listed in
9b371988 2148&_src/EDITME_&. In many cases the relevant include files and interface
168e428f 2149libraries need to be installed before compiling Exim.
9b371988 2150.cindex "cdb" "including support for"
068aaea8
PH
2151However, there are some optional lookup types (such as cdb) for which
2152the code is entirely contained within Exim, and no external include
168e428f
PH
2153files or libraries are required. When a lookup type is not included in the
2154binary, attempts to configure Exim to use it cause run time configuration
2155errors.
2156
7e6a8985
PP
2157.cindex "pkg-config" "lookups"
2158.cindex "pkg-config" "authenticators"
252e0c7b
PP
2159Many systems now use a tool called &'pkg-config'& to encapsulate information
2160about how to compile against a library; Exim has some initial support for
2161being able to use pkg-config for lookups and authenticators. For any given
2162makefile variable which starts &`LOOKUP_`& or &`AUTH_`&, you can add a new
2163variable with the &`_PC`& suffix in the name and assign as the value the
2164name of the package to be queried. The results of querying via the
2165&'pkg-config'& command will be added to the appropriate Makefile variables
2166with &`+=`& directives, so your version of &'make'& will need to support that
2167syntax. For instance:
2168.code
2169LOOKUP_SQLITE=yes
2170LOOKUP_SQLITE_PC=sqlite3
2171AUTH_GSASL=yes
2172AUTH_GSASL_PC=libgsasl
2173AUTH_HEIMDAL_GSSAPI=yes
2174AUTH_HEIMDAL_GSSAPI_PC=heimdal-gssapi
2175.endd
252e0c7b 2176
9b371988 2177.cindex "Perl" "including support for"
168e428f
PH
2178Exim can be linked with an embedded Perl interpreter, allowing Perl
2179subroutines to be called during string expansion. To enable this facility,
9b371988
PH
2180.code
2181EXIM_PERL=perl.o
2182.endd
2183must be defined in &_Local/Makefile_&. Details of this facility are given in
2184chapter &<<CHAPperl>>&.
168e428f 2185
f89d2485 2186.cindex "X11 libraries, location of"
168e428f 2187The location of the X11 libraries is something that varies a lot between
068aaea8 2188operating systems, and there may be different versions of X11 to cope
168e428f
PH
2189with. Exim itself makes no use of X11, but if you are compiling the Exim
2190monitor, the X11 libraries must be available.
9b371988
PH
2191The following three variables are set in &_OS/Makefile-Default_&:
2192.code
2193X11=/usr/X11R6
2194XINCLUDE=-I$(X11)/include
2195XLFLAGS=-L$(X11)/lib
2196.endd
168e428f 2197These are overridden in some of the operating-system configuration files. For
9b371988
PH
2198example, in &_OS/Makefile-SunOS5_& there is
2199.code
2200X11=/usr/openwin
2201XINCLUDE=-I$(X11)/include
2202XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2203.endd
168e428f
PH
2204If you need to override the default setting for your operating system, place a
2205definition of all three of these variables into your
9b371988 2206&_Local/Makefile-<ostype>_& file.
168e428f 2207
9b371988 2208.cindex "EXTRALIBS"
168e428f
PH
2209If you need to add any extra libraries to the link steps, these can be put in a
2210variable called EXTRALIBS, which appears in all the link commands, but by
2211default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2212command for linking the main Exim binary, and not for any associated utilities.
2213
9b371988 2214.cindex "DBM libraries" "configuration for building"
168e428f 2215There is also DBMLIB, which appears in the link commands for binaries that
9b371988 2216use DBM functions (see also section &<<SECTdb>>&). Finally, there is
168e428f
PH
2217EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2218binary, and which can be used, for example, to include additional X11
2219libraries.
2220
9b371988 2221.cindex "configuration file" "editing"
168e428f
PH
2222The make file copes with rebuilding Exim correctly if any of the configuration
2223files are edited. However, if an optional configuration file is deleted, it is
9b371988
PH
2224necessary to touch the associated non-optional file (that is,
2225&_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
168e428f
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2226
2227
f89d2485 2228.section "OS-specific header files" "SECID30"
9b371988
PH
2229.cindex "&_os.h_&"
2230.cindex "building Exim" "OS-specific C header files"
2231The &_OS_& directory contains a number of files with names of the form
2232&_os.h-<ostype>_&. These are system-specific C header files that should not
168e428f 2233normally need to be changed. There is a list of macro settings that are
9b371988 2234recognized in the file &_OS/os.configuring_&, which should be consulted if you
168e428f
PH
2235are porting Exim to a new operating system.
2236
2237
2238
f89d2485
PH
2239.section "Overriding build-time options for the monitor" "SECID31"
2240.cindex "building Eximon"
168e428f
PH
2241A similar process is used for overriding things when building the Exim monitor,
2242where the files that are involved are
9b371988
PH
2243.display
2244&_OS/eximon.conf-Default_&
2245&_OS/eximon.conf-_&<&'ostype'&>
2246&_Local/eximon.conf_&
2247&_Local/eximon.conf-_&<&'ostype'&>
2248&_Local/eximon.conf-_&<&'archtype'&>
2249&_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2250.endd
2251.cindex "&_Local/eximon.conf_&"
168e428f 2252As with Exim itself, the final three files need not exist, and in this case the
9b371988
PH
2253&_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2254&_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
168e428f
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2255variables of the same name, preceded by EXIMON_. For example, setting
2256EXIMON_LOG_DEPTH in the environment overrides the value of
2257LOG_DEPTH at run time.
4f578862 2258.ecindex IIDbuex
168e428f
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2259
2260
f89d2485 2261.section "Installing Exim binaries and scripts" "SECID32"
9b371988
PH
2262.cindex "installing Exim"
2263.cindex "BIN_DIRECTORY"
2264The command &`make install`& runs the &(exim_install)& script with no
2265arguments. The script copies binaries and utility scripts into the directory
2266whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2267.cindex "setuid" "installing Exim with"
068aaea8
PH
2268The install script copies files only if they are newer than the files they are
2269going to replace. The Exim binary is required to be owned by root and have the
9b371988
PH
2270&'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2271install`& as root so that it can set up the Exim binary in this way. However, in
068aaea8
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2272some special situations (for example, if a host is doing no local deliveries)
2273it may be possible to run Exim without making the binary setuid root (see
9b371988 2274chapter &<<CHAPsecurity>>& for details).
168e428f 2275
9b371988 2276.cindex "CONFIGURE_FILE"
168e428f 2277Exim's run time configuration file is named by the CONFIGURE_FILE setting
9b371988
PH
2278in &_Local/Makefile_&. If this names a single file, and the file does not
2279exist, the default configuration file &_src/configure.default_& is copied there
168e428f
PH
2280by the installation script. If a run time configuration file already exists, it
2281is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2282alternative files, no default is installed.
2283
9b371988
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2284.cindex "system aliases file"
2285.cindex "&_/etc/aliases_&"
168e428f
PH
2286One change is made to the default configuration file when it is installed: the
2287default configuration contains a router that references a system aliases file.
2288The path to this file is set to the value specified by
9b371988 2289SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
168e428f
PH
2290If the system aliases file does not exist, the installation script creates it,
2291and outputs a comment to the user.
2292
2293The created file contains no aliases, but it does contain comments about the
2294aliases a site should normally have. Mail aliases have traditionally been
9b371988
PH
2295kept in &_/etc/aliases_&. However, some operating systems are now using
2296&_/etc/mail/aliases_&. You should check if yours is one of these, and change
168e428f
PH
2297Exim's configuration if necessary.
2298
2299The default configuration uses the local host's name as the only local domain,
9b371988
PH
2300and is set up to do local deliveries into the shared directory &_/var/mail_&,
2301running as the local user. System aliases and &_.forward_& files in users' home
168e428f
PH
2302directories are supported, but no NIS or NIS+ support is configured. Domains
2303other than the name of the local host are routed using the DNS, with delivery
2304over SMTP.
2305
168e428f
PH
2306It is possible to install Exim for special purposes (such as building a binary
2307distribution) in a private part of the file system. You can do this by a
2308command such as
9b371988
PH
2309.code
2310make DESTDIR=/some/directory/ install
2311.endd
168e428f
PH
2312This has the effect of pre-pending the specified directory to all the file
2313paths, except the name of the system aliases file that appears in the default
9b371988 2314configuration. (If a default alias file is created, its name &'is'& modified.)
168e428f
PH
2315For backwards compatibility, ROOT is used if DESTDIR is not set,
2316but this usage is deprecated.
2317
9b371988
PH
2318.cindex "installing Exim" "what is not installed"
2319Running &'make install'& does not copy the Exim 4 conversion script
40df1be3
TF
2320&'convert4r4'&. You will probably run this only once if you are
2321upgrading from Exim 3. None of the documentation files in the &_doc_&
168e428f 2322directory are copied, except for the info files when you have set
9b371988 2323INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
168e428f 2324
9b371988 2325For the utility programs, old versions are renamed by adding the suffix &_.O_&
168e428f
PH
2326to their names. The Exim binary itself, however, is handled differently. It is
2327installed under a name that includes the version number and the compile number,
2aee48d6 2328for example &_exim-&version()-1_&. The script then arranges for a symbolic link
9b371988
PH
2329called &_exim_& to point to the binary. If you are updating a previous version
2330of Exim, the script takes care to ensure that the name &_exim_& is never absent
168e428f
PH
2331from the directory (as seen by other processes).
2332
9b371988
PH
2333.cindex "installing Exim" "testing the script"
2334If you want to see what the &'make install'& will do before running it for
2335real, you can pass the &%-n%& option to the installation script by this
2336command:
2337.code
2338make INSTALL_ARG=-n install
2339.endd
168e428f
PH
2340The contents of the variable INSTALL_ARG are passed to the installation
2341script. You do not need to be root to run this test. Alternatively, you can run
2342the installation script directly, but this must be from within the build
2343directory. For example, from the top-level Exim directory you could use this
2344command:
9b371988
PH
2345.code
2346(cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2347.endd
2348.cindex "installing Exim" "install script options"
168e428f
PH
2349There are two other options that can be supplied to the installation script.
2350
9b371988
PH
2351.ilist
2352&%-no_chown%& bypasses the call to change the owner of the installed binary
168e428f 2353to root, and the call to make it a setuid binary.
9b371988
PH
2354.next
2355&%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
168e428f 2356installed binary.
9b371988 2357.endlist
168e428f
PH
2358
2359INSTALL_ARG can be used to pass these options to the script. For example:
9b371988
PH
2360.code
2361make INSTALL_ARG=-no_symlink install
2362.endd
168e428f
PH
2363The installation script can also be given arguments specifying which files are
2364to be copied. For example, to install just the Exim binary, and nothing else,
2365without creating the symbolic link, you could use:
9b371988
PH
2366.code
2367make INSTALL_ARG='-no_symlink exim' install
2368.endd
168e428f
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2369
2370
2371
9b371988
PH
2372.section "Installing info documentation" "SECTinsinfdoc"
2373.cindex "installing Exim" "&'info'& documentation"
2374Not all systems use the GNU &'info'& system for documentation, and for this
168e428f
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2375reason, the Texinfo source of Exim's documentation is not included in the main
2376distribution. Instead it is available separately from the ftp site (see section
9b371988 2377&<<SECTavail>>&).
168e428f 2378
9b371988
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2379If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2380source of the documentation is found in the source tree, running &`make
2381install`& automatically builds the info files and installs them.
168e428f
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2382
2383
2384
f89d2485 2385.section "Setting up the spool directory" "SECID33"
9b371988 2386.cindex "spool directory" "creating"
168e428f
PH
2387When it starts up, Exim tries to create its spool directory if it does not
2388exist. The Exim uid and gid are used for the owner and group of the spool
2389directory. Sub-directories are automatically created in the spool directory as
2390necessary.
2391
2392
2393
2394
f89d2485 2395.section "Testing" "SECID34"
9b371988 2396.cindex "testing" "installation"
168e428f
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2397Having installed Exim, you can check that the run time configuration file is
2398syntactically valid by running the following command, which assumes that the
2399Exim binary directory is within your PATH environment variable:
9b371988
PH
2400.code
2401exim -bV
2402.endd
168e428f
PH
2403If there are any errors in the configuration file, Exim outputs error messages.
2404Otherwise it outputs the version number and build date,
2405the DBM library that is being used, and information about which drivers and
2406other optional code modules are included in the binary.
2407Some simple routing tests can be done by using the address testing option. For
2408example,
9b371988
PH
2409.display
2410&`exim -bt`& <&'local username'&>
2411.endd
168e428f 2412should verify that it recognizes a local mailbox, and
9b371988
PH
2413.display
2414&`exim -bt`& <&'remote address'&>
2415.endd
168e428f
PH
2416a remote one. Then try getting it to deliver mail, both locally and remotely.
2417This can be done by passing messages directly to Exim, without going through a
2418user agent. For example:
9b371988 2419.code
068aaea8
PH
2420exim -v postmaster@your.domain.example
2421From: user@your.domain.example
2422To: postmaster@your.domain.example
2423Subject: Testing Exim
168e428f 2424
068aaea8
PH
2425This is a test message.
2426^D
9b371988
PH
2427.endd
2428The &%-v%& option causes Exim to output some verification of what it is doing.
168e428f 2429In this case you should see copies of three log lines, one for the message's
9b371988 2430arrival, one for its delivery, and one containing &"Completed"&.
168e428f 2431
9b371988
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2432.cindex "delivery" "problems with"
2433If you encounter problems, look at Exim's log files (&'mainlog'& and
2434&'paniclog'&) to see if there is any relevant information there. Another source
168e428f 2435of information is running Exim with debugging turned on, by specifying the
9b371988 2436&%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
168e428f 2437with debugging turned on by a command of the form
9b371988
PH
2438.display
2439&`exim -d -M`& <&'exim-message-id'&>
2440.endd
2441You must be root or an &"admin user"& in order to do this. The &%-d%& option
168e428f 2442produces rather a lot of output, but you can cut this down to specific areas.
9b371988
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2443For example, if you use &%-d-all+route%& only the debugging information
2444relevant to routing is included. (See the &%-d%& option in chapter
2445&<<CHAPcommandline>>& for more details.)
168e428f 2446
9b371988
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2447.cindex '&"sticky"& bit'
2448.cindex "lock files"
168e428f
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2449One specific problem that has shown up on some sites is the inability to do
2450local deliveries into a shared mailbox directory, because it does not have the
9b371988 2451&"sticky bit"& set on it. By default, Exim tries to create a lock file before
168e428f 2452writing to a mailbox file, and if it cannot create the lock file, the delivery
9b371988 2453is deferred. You can get round this either by setting the &"sticky bit"& on the
168e428f
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2454directory, or by setting a specific group for local deliveries and allowing
2455that group to create files in the directory (see the comments above the
9b371988 2456&(local_delivery)& transport in the default configuration file). Another
168e428f 2457approach is to configure Exim not to use lock files, but just to rely on
9b371988
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2458&[fcntl()]& locking instead. However, you should do this only if all user
2459agents also use &[fcntl()]& locking. For further discussion of locking issues,
2460see chapter &<<CHAPappendfile>>&.
168e428f
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2461
2462One thing that cannot be tested on a system that is already running an MTA is
2463the receipt of incoming SMTP mail on the standard SMTP port. However, the
9b371988
PH
2464&%-oX%& option can be used to run an Exim daemon that listens on some other
2465port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2466&'exim_checkaccess'& utility can be used to check out policy controls on
168e428f
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2467incoming SMTP mail.
2468
2469Testing a new version on a system that is already running Exim can most easily
2470be done by building a binary with a different CONFIGURE_FILE setting. From
2471within the run time configuration, all other file and directory names
2472that Exim uses can be altered, in order to keep it entirely clear of the
2473production version.
2474
2475
f89d2485 2476.section "Replacing another MTA with Exim" "SECID35"
9b371988 2477.cindex "replacing another MTA"
168e428f
PH
2478Building and installing Exim for the first time does not of itself put it in
2479general use. The name by which the system's MTA is called by mail user agents
9b371988
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2480is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2481operating system), and it is necessary to make this name point to the &'exim'&
168e428f 2482binary in order to get the user agents to pass messages to Exim. This is
9b371988
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2483normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2484or &_/usr/lib/sendmail_&
2485.cindex "symbolic link" "to &'exim'& binary"
2486a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
168e428f
PH
2487privilege and executable status from the old MTA. It is then necessary to stop
2488and restart the mailer daemon, if one is running.
2489
f89d2485 2490.cindex "FreeBSD, MTA indirection"
9b371988 2491.cindex "&_/etc/mail/mailer.conf_&"
168e428f
PH
2492Some operating systems have introduced alternative ways of switching MTAs. For
2493example, if you are running FreeBSD, you need to edit the file
9b371988 2494&_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
168e428f
PH
2495described. A typical example of the contents of this file for running Exim is
2496as follows:
9b371988
PH
2497.code
2498sendmail /usr/exim/bin/exim
2499send-mail /usr/exim/bin/exim
2500mailq /usr/exim/bin/exim -bp
2501newaliases /usr/bin/true
2502.endd
2503Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2504your Exim installation is &"live"&. Check it by sending a message from your
168e428f
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2505favourite user agent.
2506
2507You should consider what to tell your users about the change of MTA. Exim may
2508have different capabilities to what was previously running, and there are
2509various operational differences such as the text of messages produced by
2510command line options and in bounce messages. If you allow your users to make
2511use of Exim's filtering capabilities, you should make the document entitled
9b371988 2512&'Exim's interface to mail filtering'& available to them.
168e428f
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2513
2514
2515
f89d2485 2516.section "Upgrading Exim" "SECID36"
9b371988 2517.cindex "upgrading Exim"
168e428f
PH
2518If you are already running Exim on your host, building and installing a new
2519version automatically makes it available to MUAs, or any other programs that
2520call the MTA directly. However, if you are running an Exim daemon, you do need
9b371988
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2521to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2522new binary. You do not need to stop processing mail in order to install a new
068aaea8
PH
2523version of Exim. The install script does not modify an existing runtime
2524configuration file.
2525
168e428f
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2526
2527
2528
f89d2485 2529.section "Stopping the Exim daemon on Solaris" "SECID37"
9b371988 2530.cindex "Solaris" "stopping Exim on"
168e428f 2531The standard command for stopping the mailer daemon on Solaris is
9b371988
PH
2532.code
2533/etc/init.d/sendmail stop
2534.endd
2535If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2536fails to stop Exim because it uses the command &'ps -e'& and greps the output
2537for the text &"sendmail"&; this is not present because the actual program name
2538(that is, &"exim"&) is given by the &'ps'& command with these options. A
2539solution is to replace the line that finds the process id with something like
2540.code
2541pid=`cat /var/spool/exim/exim-daemon.pid`
2542.endd
168e428f
PH
2543to obtain the daemon's pid directly from the file that Exim saves it in.
2544
9b371988 2545Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
168e428f
PH
2546still be received from local processes, and if automatic delivery is configured
2547(the normal case), deliveries will still occur.
2548
2549
2550
2551
9b371988
PH
2552. ////////////////////////////////////////////////////////////////////////////
2553. ////////////////////////////////////////////////////////////////////////////
168e428f 2554
9b371988 2555.chapter "The Exim command line" "CHAPcommandline"
4f578862
PH
2556.scindex IIDclo1 "command line" "options"
2557.scindex IIDclo2 "options" "command line"
168e428f
PH
2558Exim's command line takes the standard Unix form of a sequence of options,
2559each starting with a hyphen character, followed by a number of arguments. The
2560options are compatible with the main options of Sendmail, and there are also
2561some additional options, some of which are compatible with Smail 3. Certain
2562combinations of options do not make sense, and provoke an error if used.
2563The form of the arguments depends on which options are set.
2564
2565
f89d2485 2566.section "Setting options by program name" "SECID38"
9b371988
PH
2567.cindex "&'mailq'&"
2568If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
168e428f 2569were present before any other options.
9b371988 2570The &%-bp%& option requests a listing of the contents of the mail queue on the
168e428f
PH
2571standard output.
2572This feature is for compatibility with some systems that contain a command of
2573that name in one of the standard libraries, symbolically linked to
9b371988
PH
2574&_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2575
2576.cindex "&'rsmtp'&"
2577If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2578were present before any other options, for compatibility with Smail. The
2579&%-bS%& option is used for reading in a number of messages in batched SMTP
2580format.
2581
2582.cindex "&'rmail'&"
2583If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2584&%-oee%& options were present before any other options, for compatibility with
2585Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2586
2587.cindex "&'runq'&"
2588.cindex "queue runner"
2589If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2590were present before any other options, for compatibility with Smail. The &%-q%&
168e428f
PH
2591option causes a single queue runner process to be started.
2592
9b371988
PH
2593.cindex "&'newaliases'&"
2594.cindex "alias file" "building"
2595.cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2596If Exim is called under the name &'newaliases'& it behaves as if the option
2597&%-bi%& were present before any other options, for compatibility with Sendmail.
168e428f
PH
2598This option is used for rebuilding Sendmail's alias file. Exim does not have
2599the concept of a single alias file, but can be configured to run a given
9b371988 2600command if called with the &%-bi%& option.
168e428f
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2601
2602
9b371988
PH
2603.section "Trusted and admin users" "SECTtrustedadmin"
2604Some Exim options are available only to &'trusted users'& and others are
2605available only to &'admin users'&. In the description below, the phrases &"Exim
2606user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2607EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2608&%exim_group%& options. These do not necessarily have to use the name &"exim"&.
168e428f 2609
9b371988 2610.ilist
f89d2485 2611.cindex "trusted users" "definition of"
9b371988 2612.cindex "user" "trusted definition of"
168e428f 2613The trusted users are root, the Exim user, any user listed in the
9b371988
PH
2614&%trusted_users%& configuration option, and any user whose current group or any
2615supplementary group is one of those listed in the &%trusted_groups%&
168e428f 2616configuration option. Note that the Exim group is not automatically trusted.
9b371988
PH
2617
2618.cindex '&"From"& line'
2619.cindex "envelope sender"
2620Trusted users are always permitted to use the &%-f%& option or a leading
2621&"From&~"& line to specify the envelope sender of a message that is passed to
2622Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2623See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2624users to set envelope senders.
2625
2626.cindex "&'From:'& header line"
2627.cindex "&'Sender:'& header line"
2628For a trusted user, there is never any check on the contents of the &'From:'&
2629header line, and a &'Sender:'& line is never added. Furthermore, any existing
2630&'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2631
168e428f
PH
2632Trusted users may also specify a host name, host address, interface address,
2633protocol name, ident value, and authentication data when submitting a message
2634locally. Thus, they are able to insert messages into Exim's queue locally that
2635have the characteristics of messages received from a remote host. Untrusted
9b371988 2636users may in some circumstances use &%-f%&, but can never set the other values
168e428f 2637that are available to trusted users.
9b371988
PH
2638.next
2639.cindex "user" "admin definition of"
2640.cindex "admin user" "definition of"
168e428f 2641The admin users are root, the Exim user, and any user that is a member of the
9b371988 2642Exim group or of any group listed in the &%admin_groups%& configuration option.
168e428f 2643The current group does not have to be one of these groups.
9b371988 2644
168e428f
PH
2645Admin users are permitted to list the queue, and to carry out certain
2646operations on messages, for example, to force delivery failures. It is also
2647necessary to be an admin user in order to see the full information provided by
2648the Exim monitor, and full debugging output.
9b371988
PH
2649
2650By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2651Exim to attempt delivery of messages on its queue is restricted to admin users.
2652However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2653option false (that is, specifying &%no_prod_requires_admin%&).
2654
2655Similarly, the use of the &%-bp%& option to list all the messages in the queue
2656is restricted to admin users unless &%queue_list_requires_admin%& is set
168e428f 2657false.
9b371988 2658.endlist
168e428f
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2659
2660
9b371988 2661&*Warning*&: If you configure your system so that admin users are able to
168e428f
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2662edit Exim's configuration file, you are giving those users an easy way of
2663getting root. There is further discussion of this issue at the start of chapter
9b371988 2664&<<CHAPconf>>&.
168e428f
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2665
2666
2667
2668
f89d2485 2669.section "Command line options" "SECID39"
db9452a9
PH
2670Exim's command line options are described in alphabetical order below. If none
2671of the options that specifies a specific action (such as starting the daemon or
2672a queue runner, or testing an address, or receiving a message in a specific
2673format, or listing the queue) are present, and there is at least one argument
2674on the command line, &%-bm%& (accept a local message on the standard input,
2675with the arguments specifying the recipients) is assumed. Otherwise, Exim
2676outputs a brief message about itself and exits.
168e428f 2677
9b371988
PH
2678. ////////////////////////////////////////////////////////////////////////////
2679. Insert a stylized XML comment here, to identify the start of the command line
2680. options. This is for the benefit of the Perl script that automatically
2681. creates a man page for the options.
2682. ////////////////////////////////////////////////////////////////////////////
168e428f 2683
9b371988 2684.literal xml
168e428f 2685<!-- === Start of command line options === -->
9b371988 2686.literal off
168e428f
PH
2687
2688
9b371988
PH
2689.vlist
2690.vitem &%--%&
2691.oindex "--"
2692.cindex "options" "command line; terminating"
168e428f
PH
2693This is a pseudo-option whose only purpose is to terminate the options and
2694therefore to cause subsequent command line items to be treated as arguments
2695rather than options, even if they begin with hyphens.
2696
9b371988
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2697.vitem &%--help%&
2698.oindex "&%--help%&"
168e428f
PH
2699This option causes Exim to output a few sentences stating what it is.
2700The same output is generated if the Exim binary is called with no options and
2701no arguments.
2702
4b2241d2
PP
2703.vitem &%--version%&
2704.oindex "&%--version%&"
2705This option is an alias for &%-bV%& and causes version information to be
2706displayed.
2707
a3fb9793
PP
2708.new
2709.vitem &%-Ac%& &&&
2710 &%-Am%&
2711.oindex "&%-Ac%&"
2712.oindex "&%-Am%&"
2713These options are used by Sendmail for selecting configuration files and are
2714ignored by Exim.
2715.wen
2716
9b371988
PH
2717.vitem &%-B%&<&'type'&>
2718.oindex "&%-B%&"
2719.cindex "8-bit characters"
2720.cindex "Sendmail compatibility" "8-bit characters"
168e428f
PH
2721This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2722clean; it ignores this option.
2723
9b371988
PH
2724.vitem &%-bd%&
2725.oindex "&%-bd%&"
2726.cindex "daemon"
f89d2485 2727.cindex "SMTP" "listener"
9b371988 2728.cindex "queue runner"
168e428f 2729This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
9b371988
PH
2730the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2731that the daemon should also initiate periodic queue runs.
2732
2733The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2734(debugging) or &%-v%& (verifying) options are set, the daemon does not
168e428f
PH
2735disconnect from the controlling terminal. When running this way, it can be
2736stopped by pressing ctrl-C.
9b371988 2737
168e428f
PH
2738By default, Exim listens for incoming connections to the standard SMTP port on
2739all the host's running interfaces. However, it is possible to listen on other
2740ports, on multiple ports, and only on specific interfaces. Chapter
9b371988
PH
2741&<<CHAPinterfaces>>& contains a description of the options that control this.
2742
168e428f 2743When a listening daemon
9b371988
PH
2744.cindex "daemon" "process id (pid)"
2745.cindex "pid (process id)" "of daemon"
2746is started without the use of &%-oX%& (that is, without overriding the normal
2747configuration), it writes its process id to a file called &_exim-daemon.pid_&
2748in Exim's spool directory. This location can be overridden by setting
2749PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
168e428f 2750running as root.
9b371988
PH
2751
2752When &%-oX%& is used on the command line to start a listening daemon, the
2753process id is not written to the normal pid file path. However, &%-oP%& can be
168e428f 2754used to specify a path on the command line if a pid file is required.
9b371988 2755
168e428f 2756The SIGHUP signal
9b371988 2757.cindex "SIGHUP"
3cb1b51e
PH
2758.cindex "daemon" "restarting"
2759can be used to cause the daemon to re-execute itself. This should be done
2760whenever Exim's configuration file, or any file that is incorporated into it by
2761means of the &%.include%& facility, is changed, and also whenever a new version
2762of Exim is installed. It is not necessary to do this when other files that are
9b371988
PH
2763referenced from the configuration (for example, alias files) are changed,
2764because these are reread each time they are used.
2765
2766.vitem &%-bdf%&
2767.oindex "&%-bdf%&"
2768This option has the same effect as &%-bd%& except that it never disconnects
2769from the controlling terminal, even when no debugging is specified.
2770
2771.vitem &%-be%&
2772.oindex "&%-be%&"
2773.cindex "testing" "string expansion"
2774.cindex "expansion" "testing"
168e428f
PH
2775Run Exim in expansion testing mode. Exim discards its root privilege, to
2776prevent ordinary users from using this mode to read otherwise inaccessible
2777files. If no arguments are given, Exim runs interactively, prompting for lines
4f578862 2778of data. Otherwise, it processes each argument in turn.
9b371988
PH
2779
2780If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2781to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2782used without command line arguments. If successful, it uses the &[readline()]&
168e428f
PH
2783function, which provides extensive line-editing facilities, for reading the
2784test data. A line history is supported.
9b371988 2785
168e428f 2786Long expansion expressions can be split over several lines by using backslash
068aaea8 2787continuations. As in Exim's run time configuration, white space at the start of
168e428f
PH
2788continuation lines is ignored. Each argument or data line is passed through the
2789string expansion mechanism, and the result is output. Variable values from the
9b371988 2790configuration file (for example, &$qualify_domain$&) are available, but no
3cb1b51e 2791message-specific values (such as &$sender_domain$&) are set, because no message
f89d2485 2792is being processed (but see &%-bem%& and &%-Mset%&).
168e428f 2793
9b371988
PH
2794&*Note*&: If you use this mechanism to test lookups, and you change the data
2795files or databases you are using, you must exit and restart Exim before trying
2796the same lookup again. Otherwise, because each Exim process caches the results
2797of lookups, you will just get the same result as before.
9b371988 2798
3cb1b51e
PH
2799.vitem &%-bem%&&~<&'filename'&>
2800.oindex "&%-bem%&"
2801.cindex "testing" "string expansion"
2802.cindex "expansion" "testing"
2803This option operates like &%-be%& except that it must be followed by the name
2804of a file. For example:
2805.code
2806exim -bem /tmp/testmessage
2807.endd
2808The file is read as a message (as if receiving a locally-submitted non-SMTP
2809message) before any of the test expansions are done. Thus, message-specific
2810variables such as &$message_size$& and &$header_from:$& are available. However,
2811no &'Received:'& header is added to the message. If the &%-t%& option is set,
2812recipients are read from the headers in the normal way, and are shown in the
2813&$recipients$& variable. Note that recipients cannot be given on the command
2814line, because further arguments are taken as strings to expand (just like
2815&%-be%&).
3cb1b51e 2816
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2817.vitem &%-bF%&&~<&'filename'&>
2818.oindex "&%-bF%&"
2819.cindex "system filter" "testing"
2820.cindex "testing" "system filter"
2821This option is the same as &%-bf%& except that it assumes that the filter being
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2822tested is a system filter. The additional commands that are available only in
2823system filters are recognized.
2824
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2825.vitem &%-bf%&&~<&'filename'&>
2826.oindex "&%-bf%&"
2827.cindex "filter" "testing"
2828.cindex "testing" "filter file"
2829.cindex "forward file" "testing"
2830.cindex "testing" "forward file"
2831.cindex "Sieve filter" "testing"
168e428f
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2832This option runs Exim in user filter testing mode; the file is the filter file
2833to be tested, and a test message must be supplied on the standard input. If
2834there are no message-dependent tests in the filter, an empty file can be
2835supplied.
168e428f 2836
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2837If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2838can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2839filter and a user filter in the same run. For example:
2840.code
2841exim -bF /system/filter -bf /user/filter </test/message
2842.endd
168e428f
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2843This is helpful when the system filter adds header lines or sets filter
2844variables that are used by the user filter.
168e428f 2845
9b371988
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2846If the test filter file does not begin with one of the special lines
2847.code
2848# Exim filter
2849# Sieve filter
2850.endd
2851it is taken to be a normal &_.forward_& file, and is tested for validity under
2852that interpretation. See sections &<<SECTitenonfilred>>& to
2853&<<SECTspecitredli>>& for a description of the possible contents of non-filter
2854redirection lists.
2855
2856The result of an Exim command that uses &%-bf%&, provided no errors are
168e428f
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2857detected, is a list of the actions that Exim would try to take if presented
2858with the message for real. More details of filter testing are given in the
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2859separate document entitled &'Exim's interfaces to mail filtering'&.
2860
168e428f 2861When testing a filter file,
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2862.cindex "&""From""& line"
2863.cindex "envelope sender"
f89d2485 2864.oindex "&%-f%&" "for filter testing"
9b371988
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2865the envelope sender can be set by the &%-f%& option,
2866or by a &"From&~"& line at the start of the test message. Various parameters
2867that would normally be taken from the envelope recipient address of the message
2868can be set by means of additional command line options (see the next four
2869options).
2870
2871.vitem &%-bfd%&&~<&'domain'&>
2872.oindex "&%-bfd%&"
f89d2485 2873.vindex "&$qualify_domain$&"
168e428f 2874This sets the domain of the recipient address when a filter file is being
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2875tested by means of the &%-bf%& option. The default is the value of
2876&$qualify_domain$&.
168e428f 2877
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2878.vitem &%-bfl%&&~<&'local&~part'&>
2879.oindex "&%-bfl%&"
168e428f 2880This sets the local part of the recipient address when a filter file is being
9b371988 2881tested by means of the &%-bf%& option. The default is the username of the
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2882process that calls Exim. A local part should be specified with any prefix or
2883suffix stripped, because that is how it appears to the filter when a message is
2884actually being delivered.
2885
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2886.vitem &%-bfp%&&~<&'prefix'&>
2887.oindex "&%-bfp%&"
168e428f 2888This sets the prefix of the local part of the recipient address when a filter
9b371988 2889file is being tested by means of the &%-bf%& option. The default is an empty
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2890prefix.
2891
9b371988
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2892.vitem &%-bfs%&&~<&'suffix'&>
2893.oindex "&%-bfs%&"
168e428f 2894This sets the suffix of the local part of the recipient address when a filter
9b371988 2895file is being tested by means of the &%-bf%& option. The default is an empty
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2896suffix.
2897
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2898.vitem &%-bh%&&~<&'IP&~address'&>
2899.oindex "&%-bh%&"
2900.cindex "testing" "incoming SMTP"
2901.cindex "SMTP" "testing incoming"
2902.cindex "testing" "relay control"
2903.cindex "relaying" "testing configuration"
2904.cindex "policy control" "testing"
2905.cindex "debugging" "&%-bh%& option"
168e428f
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2906This option runs a fake SMTP session as if from the given IP address, using the
2907standard input and output. The IP address may include a port number at the end,
2908after a full stop. For example:
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2909.code
2910exim -bh 10.9.8.7.1234
2911exim -bh fe80::a00:20ff:fe86:a061.5678
2912.endd
168e428f 2913When an IPv6 address is given, it is converted into canonical form. In the case
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2914of the second example above, the value of &$sender_host_address$& after
2915conversion to the canonical form is
2916&`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2917
168e428f 2918Comments as to what is going on are written to the standard error file. These
9b371988 2919include lines beginning with &"LOG"& for anything that would have been logged.
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2920This facility is provided for testing configuration options for incoming
2921messages, to make sure they implement the required policy. For example, you can
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2922test your relay controls using &%-bh%&.
2923
2924&*Warning 1*&:
2925.cindex "RFC 1413"
db9452a9
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2926You can test features of the configuration that rely on ident (RFC 1413)
2927information by using the &%-oMt%& option. However, Exim cannot actually perform
2928an ident callout when testing using &%-bh%& because there is no incoming SMTP
2929connection.
9b371988
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2930
2931&*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2932are also skipped when testing using &%-bh%&. If you want these callouts to
2933occur, use &%-bhc%& instead.
2934
168e428f
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2935Messages supplied during the testing session are discarded, and nothing is
2936written to any of the real log files. There may be pauses when DNS (and other)
9b371988 2937lookups are taking place, and of course these may time out. The &%-oMi%& option
db9452a9
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2938can be used to specify a specific IP interface and port if this is important,
2939and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2940session were authenticated.
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2941
2942The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
168e428f 2943output just states whether a given recipient address from a given host is
9b371988 2944acceptable or not. See section &<<SECTcheckaccess>>&.
168e428f 2945
3cb1b51e 2946Features such as authentication and encryption, where the client input is not
f89d2485
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2947plain text, cannot easily be tested with &%-bh%&. Instead, you should use a
2948specialized SMTP test program such as
3cb1b51e 2949&url(http://jetmore.org/john/code/#swaks,swaks).
3cb1b51e 2950
9b371988
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2951.vitem &%-bhc%&&~<&'IP&~address'&>
2952.oindex "&%-bhc%&"
2953This option operates in the same way as &%-bh%&, except that address
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2954verification callouts are performed if required. This includes consulting and
2955updating the callout cache database.
2956
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2957.vitem &%-bi%&
2958.oindex "&%-bi%&"
2959.cindex "alias file" "building"
2960.cindex "building alias file"
2961.cindex "Sendmail compatibility" "&%-bi%& option"
2962Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
168e428f 2963Exim does not have the concept of a single alias file, and so it cannot mimic
9b371988 2964this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
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2965tend to appear in various scripts such as NIS make files, so the option must be
2966recognized.
9b371988
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2967
2968If &%-bi%& is encountered, the command specified by the &%bi_command%&
168e428f 2969configuration option is run, under the uid and gid of the caller of Exim. If
9b371988
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2970the &%-oA%& option is used, its value is passed to the command as an argument.
2971The command set by &%bi_command%& may not contain arguments. The command can
2972use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2973if this is required. If the &%bi_command%& option is not set, calling Exim with
2974&%-bi%& is a no-op.
2975
12f69989 2976.new
36a3ae5f 2977. // Keep :help first, then the rest in alphabetical order
98a90c36
PP
2978.vitem &%-bI:help%&
2979.oindex "&%-bI:help%&"
2980.cindex "querying exim information"
2981We shall provide various options starting &`-bI:`& for querying Exim for
2982information. The output of many of these will be intended for machine
2983consumption. This one is not. The &%-bI:help%& option asks Exim for a
2984synopsis of supported options beginning &`-bI:`&. Use of any of these
2985options shall cause Exim to exit after producing the requested output.
2986
36a3ae5f
PP
2987.vitem &%-bI:dscp%&
2988.oindex "&%-bI:dscp%&"
2989.cindex "DSCP" "values"
2990This option causes Exim to emit an alphabetically sorted list of all
2991recognised DSCP names.
2992
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PP
2993.vitem &%-bI:sieve%&
2994.oindex "&%-bI:sieve%&"
2995.cindex "Sieve filter" "capabilities"
2996This option causes Exim to emit an alphabetically sorted list of all supported
2997Sieve protocol extensions on stdout, one per line. This is anticipated to be
2998useful for ManageSieve (RFC 5804) implementations, in providing that protocol's
2999&`SIEVE`& capability response line. As the precise list may depend upon
3000compile-time build options, which this option will adapt to, this is the only
3001way to guarantee a correct response.
12f69989 3002.wen
98a90c36 3003
9b371988
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3004.vitem &%-bm%&
3005.oindex "&%-bm%&"
3006.cindex "local message reception"
168e428f 3007This option runs an Exim receiving process that accepts an incoming,
a543079f 3008locally-generated message on the standard input. The recipients are given as the
9b371988 3009command arguments (except when &%-t%& is also present &-- see below). Each
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3010argument can be a comma-separated list of RFC 2822 addresses. This is the
3011default option for selecting the overall action of an Exim call; it is assumed
3012if no other conflicting option is present.
9b371988 3013
168e428f 3014If any addresses in the message are unqualified (have no domain), they are
9b371988
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3015qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
3016options, as appropriate. The &%-bnq%& option (see below) provides a way of
168e428f 3017suppressing this for special cases.
9b371988 3018
168e428f 3019Policy checks on the contents of local messages can be enforced by means of
9b371988
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3020the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
3021
3022.cindex "return code" "for &%-bm%&"
3023The return code is zero if the message is successfully accepted. Otherwise, the
3024action is controlled by the &%-oe%&&'x'& option setting &-- see below.
3025
168e428f 3026The format
9b371988
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3027.cindex "message" "format"
3028.cindex "format" "message"
3029.cindex "&""From""& line"
3030.cindex "UUCP" "&""From""& line"
3031.cindex "Sendmail compatibility" "&""From""& line"
168e428f
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3032of the message must be as defined in RFC 2822, except that, for
3033compatibility with Sendmail and Smail, a line in one of the forms
9b371988
PH
3034.code
3035From sender Fri Jan 5 12:55 GMT 1997
3036From sender Fri, 5 Jan 97 12:55:01
3037.endd
168e428f
PH
3038(with the weekday optional, and possibly with additional text after the date)
3039is permitted to appear at the start of the message. There appears to be no
3040authoritative specification of the format of this line. Exim recognizes it by
9b371988 3041matching against the regular expression defined by the &%uucp_from_pattern%&
168e428f 3042option, which can be changed if necessary.
9b371988 3043
f89d2485
PH
3044.oindex "&%-f%&" "overriding &""From""& line"
3045The specified sender is treated as if it were given as the argument to the
9b371988 3046&%-f%& option, but if a &%-f%& option is also present, its argument is used in
168e428f
PH
3047preference to the address taken from the message. The caller of Exim must be a
3048trusted user for the sender of a message to be set in this way.
3049
5b257915
PP
3050.vitem &%-bmalware%&&~<&'filename'&>
3051.oindex "&%-bmalware%&"
3052.cindex "testing", "malware"
3053.cindex "malware scan test"
3054This debugging option causes Exim to scan the given file,
3055using the malware scanning framework. The option of &%av_scanner%& influences
3056this option, so if &%av_scanner%&'s value is dependent upon an expansion then
3057the expansion should have defaults which apply to this invocation. ACLs are
3058not invoked, so if &%av_scanner%& references an ACL variable then that variable
3059will never be populated and &%-bmalware%& will fail.
3060
3061Exim will have changed working directory before resolving the filename, so
3062using fully qualified pathnames is advisable. Exim will be running as the Exim
3063user when it tries to open the file, rather than as the invoking user.
3064This option requires admin privileges.
3065
3066The &%-bmalware%& option will not be extended to be more generally useful,
3067there are better tools for file-scanning. This option exists to help
3068administrators verify their Exim and AV scanner configuration.
3069