Add an openssl_options main configuration option, to allow administrators to
[exim.git] / doc / doc-docbook / spec.xfpt
CommitLineData
77bb000f 1. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.75 2010/06/05 09:10:08 pdp Exp $
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2.
3. /////////////////////////////////////////////////////////////////////////////
4. This is the primary source of the Exim Manual. It is an xfpt document that is
5. converted into DocBook XML for subsequent conversion into printing and online
6. formats. The markup used herein is "standard" xfpt markup, with some extras.
7. The markup is summarized in a file called Markup.txt.
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8.
9. WARNING: When you use the .new macro, make sure it appears *before* any
10. adjacent index items; otherwise you get an empty "paragraph" which causes
11. unwanted vertical space.
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12. /////////////////////////////////////////////////////////////////////////////
13
14.include stdflags
15.include stdmacs
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16
17. /////////////////////////////////////////////////////////////////////////////
33393583 18. This outputs the standard DocBook boilerplate.
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19. /////////////////////////////////////////////////////////////////////////////
20
33393583 21.docbook
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22
23. /////////////////////////////////////////////////////////////////////////////
24. These lines are processing instructions for the Simple DocBook Processor that
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25. Philip Hazel has developed as a less cumbersome way of making PostScript and
26. PDFs than using xmlto and fop. They will be ignored by all other XML
27. processors.
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28. /////////////////////////////////////////////////////////////////////////////
29
30.literal xml
31<?sdop
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32 foot_right_recto="&chaptertitle; (&chapternumber;)"
33 foot_right_verso="&chaptertitle; (&chapternumber;)"
3cb1b51e 34 toc_chapter_blanks="yes,yes"
595028e4 35 table_warn_overflow="overprint"
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36?>
37.literal off
9b371988 38
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39. /////////////////////////////////////////////////////////////////////////////
40. This generate the outermost <book> element that wraps then entire document.
41. /////////////////////////////////////////////////////////////////////////////
42
43.book
44
45. /////////////////////////////////////////////////////////////////////////////
46. These definitions set some parameters and save some typing. Remember that
47. the <bookinfo> element must also be updated for each new edition.
48. /////////////////////////////////////////////////////////////////////////////
49
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50.set previousversion "4.71"
51.set version "4.72"
f89d2485 52
33393583 53.set ACL "access control lists (ACLs)"
f89d2485 54.set I "&nbsp;&nbsp;&nbsp;&nbsp;"
33393583 55
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56
57. /////////////////////////////////////////////////////////////////////////////
58. Additional xfpt markup used by this document, over and above the default
59. provided in the xfpt library.
60. /////////////////////////////////////////////////////////////////////////////
61
62. --- Override the &$ flag to automatically insert a $ with the variable name
63
64.flag &$ $& "<varname>$" "</varname>"
65
66. --- Short flags for daggers in option headings. They will always be inside
67. --- an italic string, but we want the daggers to be roman.
68
69.flag &!! "</emphasis>&dagger;<emphasis>"
70.flag &!? "</emphasis>&Dagger;<emphasis>"
71
72. --- A macro for an Exim option definition heading, generating a one-line
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73. --- table with four columns. For cases when the option name is given with
74. --- a space, so that it can be split, a fifth argument is used for the
75. --- index entry.
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76
77.macro option
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78.arg 5
79.oindex "&%$5%&"
80.endarg
81.arg -5
3cb1b51e 82.oindex "&%$1%&"
0a4e3112 83.endarg
f89d2485 84.itable all 0 0 4 8* left 6* center 6* center 6* right
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85.row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&"
86.endtable
87.endmacro
88
89. --- A macro for the common 2-column tables. The width of the first column
90. --- is suitable for the many tables at the start of the main options chapter;
91. --- the small number of other 2-column tables override it.
92
db9452a9 93.macro table2 196pt 254pt
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94.itable none 0 0 2 $1 left $2 left
95.endmacro
96
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97. --- A macro that generates .row, but puts &I; at the start of the first
98. --- argument, thus indenting it. Assume a minimum of two arguments, and
99. --- allow up to four arguments, which is as many as we'll ever need.
100
101.macro irow
102.arg 4
103.row "&I;$1" "$2" "$3" "$4"
104.endarg
105.arg -4
106.arg 3
107.row "&I;$1" "$2" "$3"
108.endarg
109.arg -3
110.row "&I;$1" "$2"
111.endarg
112.endarg
113.endmacro
114
115. --- Macros for option, variable, and concept index entries. For a "range"
116. --- style of entry, use .scindex for the start and .ecindex for the end. The
117. --- first argument of .scindex and the only argument of .ecindex must be the
118. --- ID that ties them together.
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119
120.macro cindex
121&<indexterm role="concept">&
122&<primary>&$1&</primary>&
123.arg 2
124&<secondary>&$2&</secondary>&
125.endarg
126&</indexterm>&
127.endmacro
128
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129.macro scindex
130&<indexterm role="concept" id="$1" class="startofrange">&
131&<primary>&$2&</primary>&
132.arg 3
133&<secondary>&$3&</secondary>&
134.endarg
135&</indexterm>&
136.endmacro
137
138.macro ecindex
139&<indexterm role="concept" startref="$1" class="endofrange"/>&
140.endmacro
141
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142.macro oindex
143&<indexterm role="option">&
144&<primary>&$1&</primary>&
145.arg 2
146&<secondary>&$2&</secondary>&
147.endarg
148&</indexterm>&
149.endmacro
150
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151.macro vindex
152&<indexterm role="variable">&
153&<primary>&$1&</primary>&
154.arg 2
155&<secondary>&$2&</secondary>&
156.endarg
157&</indexterm>&
158.endmacro
159
9b371988 160.macro index
f89d2485 161.echo "** Don't use .index; use .cindex or .oindex or .vindex"
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162.endmacro
163. ////////////////////////////////////////////////////////////////////////////
164
165
166. ////////////////////////////////////////////////////////////////////////////
167. The <bookinfo> element is removed from the XML before processing for Ascii
168. output formats.
169. ////////////////////////////////////////////////////////////////////////////
170
171.literal xml
172<bookinfo>
173<title>Specification of the Exim Mail Transfer Agent</title>
174<titleabbrev>The Exim MTA</titleabbrev>
fdf795c0 175<date>29 May 2010</date>
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176<author><firstname>Exim</firstname><surname>Maintainers</surname></author>
177<authorinitials>EM</authorinitials>
9b371988 178<revhistory><revision>
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179 <revnumber>4.72</revnumber>
180 <date>29 May 2010</date>
7b4c60eb 181 <authorinitials>EM</authorinitials>
9b371988 182</revision></revhistory>
68950195 183<copyright><year>2009</year><holder>University of Cambridge</holder></copyright>
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184</bookinfo>
185.literal off
186
187
188. /////////////////////////////////////////////////////////////////////////////
189. This chunk of literal XML implements index entries of the form "x, see y" and
190. "x, see also y". However, the DocBook DTD doesn't allow <indexterm> entries
191. at the top level, so we have to put the .chapter directive first.
192. /////////////////////////////////////////////////////////////////////////////
193
f89d2485 194.chapter "Introduction" "CHID1"
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195.literal xml
196
f89d2485 197<indexterm role="variable">
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198 <primary>$1, $2, etc.</primary>
199 <see><emphasis>numerical variables</emphasis></see>
200</indexterm>
201<indexterm role="concept">
202 <primary>address</primary>
203 <secondary>rewriting</secondary>
204 <see><emphasis>rewriting</emphasis></see>
205</indexterm>
206<indexterm role="concept">
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207 <primary>Bounce Address Tag Validation</primary>
208 <see><emphasis>BATV</emphasis></see>
209</indexterm>
210<indexterm role="concept">
211 <primary>Client SMTP Authorization</primary>
212 <see><emphasis>CSA</emphasis></see>
213</indexterm>
214<indexterm role="concept">
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215 <primary>CR character</primary>
216 <see><emphasis>carriage return</emphasis></see>
217</indexterm>
218<indexterm role="concept">
219 <primary>CRL</primary>
220 <see><emphasis>certificate revocation list</emphasis></see>
221</indexterm>
222<indexterm role="concept">
223 <primary>delivery</primary>
224 <secondary>failure report</secondary>
225 <see><emphasis>bounce message</emphasis></see>
226</indexterm>
227<indexterm role="concept">
228 <primary>dialup</primary>
229 <see><emphasis>intermittently connected hosts</emphasis></see>
230</indexterm>
231<indexterm role="concept">
232 <primary>exiscan</primary>
233 <see><emphasis>content scanning</emphasis></see>
234</indexterm>
235<indexterm role="concept">
236 <primary>failover</primary>
237 <see><emphasis>fallback</emphasis></see>
238</indexterm>
239<indexterm role="concept">
240 <primary>fallover</primary>
241 <see><emphasis>fallback</emphasis></see>
242</indexterm>
243<indexterm role="concept">
244 <primary>filter</primary>
245 <secondary>Sieve</secondary>
246 <see><emphasis>Sieve filter</emphasis></see>
247</indexterm>
248<indexterm role="concept">
249 <primary>ident</primary>
250 <see><emphasis>RFC 1413</emphasis></see>
251</indexterm>
252<indexterm role="concept">
253 <primary>LF character</primary>
254 <see><emphasis>linefeed</emphasis></see>
255</indexterm>
256<indexterm role="concept">
257 <primary>maximum</primary>
595028e4 258 <seealso><emphasis>limit</emphasis></seealso>
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259</indexterm>
260<indexterm role="concept">
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261 <primary>monitor</primary>
262 <see><emphasis>Exim monitor</emphasis></see>
263</indexterm>
264<indexterm role="concept">
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265 <primary>no_<emphasis>xxx</emphasis></primary>
266 <see>entry for xxx</see>
267</indexterm>
268<indexterm role="concept">
269 <primary>NUL</primary>
270 <see><emphasis>binary zero</emphasis></see>
271</indexterm>
272<indexterm role="concept">
273 <primary>passwd file</primary>
274 <see><emphasis>/etc/passwd</emphasis></see>
275</indexterm>
276<indexterm role="concept">
277 <primary>process id</primary>
278 <see><emphasis>pid</emphasis></see>
279</indexterm>
280<indexterm role="concept">
281 <primary>RBL</primary>
282 <see><emphasis>DNS list</emphasis></see>
283</indexterm>
284<indexterm role="concept">
285 <primary>redirection</primary>
286 <see><emphasis>address redirection</emphasis></see>
287</indexterm>
288<indexterm role="concept">
289 <primary>return path</primary>
290 <seealso><emphasis>envelope sender</emphasis></seealso>
291</indexterm>
292<indexterm role="concept">
293 <primary>scanning</primary>
294 <see><emphasis>content scanning</emphasis></see>
295</indexterm>
296<indexterm role="concept">
297 <primary>SSL</primary>
298 <see><emphasis>TLS</emphasis></see>
299</indexterm>
300<indexterm role="concept">
301 <primary>string</primary>
302 <secondary>expansion</secondary>
303 <see><emphasis>expansion</emphasis></see>
304</indexterm>
305<indexterm role="concept">
306 <primary>top bit</primary>
307 <see><emphasis>8-bit characters</emphasis></see>
308</indexterm>
309<indexterm role="concept">
310 <primary>variables</primary>
311 <see><emphasis>expansion, variables</emphasis></see>
312</indexterm>
313<indexterm role="concept">
314 <primary>zero, binary</primary>
315 <see><emphasis>binary zero</emphasis></see>
316</indexterm>
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317
318.literal off
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319
320
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321. /////////////////////////////////////////////////////////////////////////////
322. This is the real start of the first chapter. See the comment above as to why
323. we can't have the .chapter line here.
324. chapter "Introduction"
325. /////////////////////////////////////////////////////////////////////////////
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326
327Exim is a mail transfer agent (MTA) for hosts that are running Unix or
328Unix-like operating systems. It was designed on the assumption that it would be
329run on hosts that are permanently connected to the Internet. However, it can be
330used on intermittently connected hosts with suitable configuration adjustments.
331
332Configuration files currently exist for the following operating systems: AIX,
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333BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, Dragonfly, FreeBSD, GNU/Hurd,
334GNU/Linux, HI-OSF (Hitachi), HI-UX, HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD,
335OpenUNIX, QNX, SCO, SCO SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4,
336Tru64-Unix (formerly Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware.
337Some of these operating systems are no longer current and cannot easily be
338tested, so the configuration files may no longer work in practice.
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339
340There are also configuration files for compiling Exim in the Cygwin environment
341that can be installed on systems running Windows. However, this document does
342not contain any information about running Exim in the Cygwin environment.
343
344The terms and conditions for the use and distribution of Exim are contained in
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345the file &_NOTICE_&. Exim is distributed under the terms of the GNU General
346Public Licence, a copy of which may be found in the file &_LICENCE_&.
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347
348The use, supply or promotion of Exim for the purpose of sending bulk,
349unsolicited electronic mail is incompatible with the basic aims of the program,
350which revolve around the free provision of a service that enhances the quality
351of personal communications. The author of Exim regards indiscriminate
352mass-mailing as an antisocial, irresponsible abuse of the Internet.
353
354Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
355experience of running and working on the Smail 3 code, I could never have
356contemplated starting to write a new MTA. Many of the ideas and user interfaces
357were originally taken from Smail 3, though the actual code of Exim is entirely
358new, and has developed far beyond the initial concept.
359
360Many people, both in Cambridge and around the world, have contributed to the
361development and the testing of Exim, and to porting it to various operating
362systems. I am grateful to them all. The distribution now contains a file called
9b371988 363&_ACKNOWLEDGMENTS_&, in which I have started recording the names of
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364contributors.
365
366
f89d2485 367.section "Exim documentation" "SECID1"
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368. Keep this example change bar when updating the documentation!
369.new
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370.cindex "documentation"
371This edition of the Exim specification applies to version &version; of Exim.
372Substantive changes from the &previousversion; edition are marked in some
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373renditions of the document; this paragraph is so marked if the rendition is
374capable of showing a change indicator.
800d5176 375.wen
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376
377This document is very much a reference manual; it is not a tutorial. The reader
378is expected to have some familiarity with the SMTP mail transfer protocol and
379with general Unix system administration. Although there are some discussions
380and examples in places, the information is mostly organized in a way that makes
381it easy to look up, rather than in a natural order for sequential reading.
382Furthermore, the manual aims to cover every aspect of Exim in detail, including
383a number of rarely-used, special-purpose features that are unlikely to be of
384very wide interest.
385
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386.cindex "books about Exim"
387An &"easier"& discussion of Exim which provides more in-depth explanatory,
388introductory, and tutorial material can be found in a book entitled &'The Exim
595028e4 389SMTP Mail Server'& (second edition, 2007), published by UIT Cambridge
9b371988 390(&url(http://www.uit.co.uk/exim-book/)).
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391
392This book also contains a chapter that gives a general introduction to SMTP and
393Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
394with the latest release of Exim. (Note that the earlier book about Exim,
395published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
396
9b371988 397.cindex "Debian" "information sources"
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398If you are using a Debian distribution of Exim, you will find information about
399Debian-specific features in the file
f89d2485 400&_/usr/share/doc/exim4-base/README.Debian_&.
9b371988 401The command &(man update-exim.conf)& is another source of Debian-specific
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402information.
403
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404.cindex "&_doc/NewStuff_&"
405.cindex "&_doc/ChangeLog_&"
406.cindex "change log"
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407As the program develops, there may be features in newer versions that have not
408yet made it into this document, which is updated only when the most significant
409digit of the fractional part of the version number changes. Specifications of
410new features that are not yet in this manual are placed in the file
9b371988 411&_doc/NewStuff_& in the Exim distribution.
168e428f 412
9b371988 413Some features may be classified as &"experimental"&. These may change
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414incompatibly while they are developing, or even be withdrawn. For this reason,
415they are not documented in this manual. Information about experimental features
9b371988 416can be found in the file &_doc/experimental.txt_&.
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417
418All changes to the program (whether new features, bug fixes, or other kinds of
9b371988 419change) are noted briefly in the file called &_doc/ChangeLog_&.
168e428f 420
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421.cindex "&_doc/spec.txt_&"
422This specification itself is available as an ASCII file in &_doc/spec.txt_& so
423that it can easily be searched with a text editor. Other files in the &_doc_&
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424directory are:
425
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426.table2 100pt
427.row &_OptionLists.txt_& "list of all options in alphabetical order"
428.row &_dbm.discuss.txt_& "discussion about DBM libraries"
429.row &_exim.8_& "a man page of Exim's command line options"
430.row &_experimental.txt_& "documentation of experimental features"
431.row &_filter.txt_& "specification of the filter language"
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432.row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
433.row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
434.endtable
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435
436The main specification and the specification of the filtering language are also
437available in other formats (HTML, PostScript, PDF, and Texinfo). Section
9b371988 438&<<SECTavail>>& below tells you how to get hold of these.
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439
440
441
f89d2485 442.section "FTP and web sites" "SECID2"
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443.cindex "web site"
444.cindex "FTP site"
068aaea8 445The primary site for Exim source distributions is currently the University of
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446Cambridge's FTP site, whose contents are described in &'Where to find the Exim
447distribution'& below. In addition, there is a web site and an FTP site at
448&%exim.org%&. These are now also hosted at the University of Cambridge. The
449&%exim.org%& site was previously hosted for a number of years by Energis
450Squared, formerly Planet Online Ltd, whose support I gratefully acknowledge.
451
452.cindex "wiki"
453.cindex "FAQ"
168e428f 454As well as Exim distribution tar files, the Exim web site contains a number of
f89d2485 455differently formatted versions of the documentation. A recent addition to the
7d0ab55c 456online information is the Exim wiki (&url(http://wiki.exim.org)),
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457which contains what used to be a separate FAQ, as well as various other
458examples, tips, and know-how that have been contributed by Exim users.
459
460.cindex Bugzilla
7d0ab55c 461An Exim Bugzilla exists at &url(http://bugs.exim.org). You can use
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462this to report bugs, and also to add items to the wish list. Please search
463first to check that you are not duplicating a previous entry.
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464
465
466
f89d2485 467.section "Mailing lists" "SECID3"
9b371988 468.cindex "mailing lists" "for Exim users"
f89d2485 469The following Exim mailing lists exist:
168e428f 470
9b371988 471.table2 140pt
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472.row &'exim-users@exim.org'& "General discussion list"
473.row &'exim-dev@exim.org'& "Discussion of bugs, enhancements, etc."
474.row &'exim-announce@exim.org'& "Moderated, low volume announcements list"
475.row &'exim-future@exim.org'& "Discussion of long-term development"
9b371988 476.endtable
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477
478You can subscribe to these lists, change your existing subscriptions, and view
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479or search the archives via the mailing lists link on the Exim home page.
480.cindex "Debian" "mailing list for"
4f578862 481If you are using a Debian distribution of Exim, you may wish to subscribe to
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482the Debian-specific mailing list &'pkg-exim4-users@lists.alioth.debian.org'&
483via this web page:
484.display
485&url(http://lists.alioth.debian.org/mailman/listinfo/pkg-exim4-users)
486.endd
487Please ask Debian-specific questions on this list and not on the general Exim
488lists.
9b371988 489
f89d2485 490.section "Exim training" "SECID4"
9b371988 491.cindex "training courses"
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492Training courses in Cambridge (UK) used to be run annually by the author of
493Exim, before he retired. At the time of writing, there are no plans to run
494further Exim courses in Cambridge. However, if that changes, relevant
495information will be posted at &url(http://www-tus.csx.cam.ac.uk/courses/exim/).
168e428f 496
f89d2485 497.section "Bug reports" "SECID5"
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498.cindex "bug reports"
499.cindex "reporting bugs"
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500Reports of obvious bugs can be emailed to &'bugs@exim.org'& or reported
501via the Bugzilla (&url(http://bugs.exim.org)). However, if you are unsure
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502whether some behaviour is a bug or not, the best thing to do is to post a
503message to the &'exim-dev'& mailing list and have it discussed.
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504
505
506
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507.section "Where to find the Exim distribution" "SECTavail"
508.cindex "FTP site"
509.cindex "distribution" "ftp site"
168e428f 510The master ftp site for the Exim distribution is
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511.display
512&*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim*&
513.endd
168e428f 514This is mirrored by
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515.display
516&*ftp://ftp.exim.org/pub/exim*&
517.endd
518The file references that follow are relative to the &_exim_& directories at
519these sites. There are now quite a number of independent mirror sites around
520the world. Those that I know about are listed in the file called &_Mirrors_&.
521
522Within the &_exim_& directory there are subdirectories called &_exim3_& (for
523previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
524distributions), and &_Testing_& for testing versions. In the &_exim4_&
168e428f 525subdirectory, the current release can always be found in files called
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526.display
527&_exim-n.nn.tar.gz_&
528&_exim-n.nn.tar.bz2_&
529.endd
530where &'n.nn'& is the highest such version number in the directory. The two
168e428f 531files contain identical data; the only difference is the type of compression.
9b371988 532The &_.bz2_& file is usually a lot smaller than the &_.gz_& file.
168e428f 533
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534.cindex "distribution" "signing details"
535.cindex "distribution" "public key"
536.cindex "public key for signed distribution"
210f147e 537The distributions are currently signed with Nigel Metheringham's GPG key. The
168e428f 538corresponding public key is available from a number of keyservers, and there is
210f147e 539also a copy in the file &_nigel-pubkey.asc_&. The signatures for the tar bundles are
168e428f 540in:
9b371988 541.display
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542&_exim-n.nn.tar.gz.asc_&
543&_exim-n.nn.tar.bz2.asc_&
9b371988 544.endd
168e428f 545For each released version, the log of changes is made separately available in a
9b371988 546separate file in the directory &_ChangeLogs_& so that it is possible to
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547find out what has changed without having to download the entire distribution.
548
9b371988 549.cindex "documentation" "available formats"
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550The main distribution contains ASCII versions of this specification and other
551documentation; other formats of the documents are available in separate files
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552inside the &_exim4_& directory of the FTP site:
553.display
554&_exim-html-n.nn.tar.gz_&
555&_exim-pdf-n.nn.tar.gz_&
556&_exim-postscript-n.nn.tar.gz_&
557&_exim-texinfo-n.nn.tar.gz_&
558.endd
559These tar files contain only the &_doc_& directory, not the complete
560distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
168e428f 561
168e428f 562
f89d2485 563.section "Limitations" "SECID6"
9b371988
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564.ilist
565.cindex "limitations of Exim"
566.cindex "bang paths" "not handled by Exim"
567Exim is designed for use as an Internet MTA, and therefore handles addresses in
568RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
569simple two-component bang paths can be converted by a straightforward rewriting
570configuration. This restriction does not prevent Exim from being interfaced to
571UUCP as a transport mechanism, provided that domain addresses are used.
572.next
573.cindex "domainless addresses"
574.cindex "address" "without domain"
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575Exim insists that every address it handles has a domain attached. For incoming
576local messages, domainless addresses are automatically qualified with a
577configured domain value. Configuration options specify from which remote
578systems unqualified addresses are acceptable. These are then qualified on
579arrival.
9b371988
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580.next
581.cindex "transport" "external"
582.cindex "external transports"
583The only external transport mechanisms that are currently implemented are SMTP
584and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
168e428f 585transport is available, and there are facilities for writing messages to files
9b371988
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586and pipes, optionally in &'batched SMTP'& format; these facilities can be used
587to send messages to other transport mechanisms such as UUCP, provided they can
588handle domain-style addresses. Batched SMTP input is also catered for.
589.next
590Exim is not designed for storing mail for dial-in hosts. When the volumes of
591such mail are large, it is better to get the messages &"delivered"& into files
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592(that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
593other means.
9b371988
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594.next
595Although Exim does have basic facilities for scanning incoming messages, these
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596are not comprehensive enough to do full virus or spam scanning. Such operations
597are best carried out using additional specialized software packages. If you
598compile Exim with the content-scanning extension, straightforward interfaces to
599a number of common scanners are provided.
9b371988 600.endlist
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601
602
f89d2485 603.section "Run time configuration" "SECID7"
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604Exim's run time configuration is held in a single text file that is divided
605into a number of sections. The entries in this file consist of keywords and
606values, in the style of Smail 3 configuration files. A default configuration
607file which is suitable for simple online installations is provided in the
9b371988 608distribution, and is described in chapter &<<CHAPdefconfil>>& below.
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609
610
f89d2485 611.section "Calling interface" "SECID8"
9b371988 612.cindex "Sendmail compatibility" "command line interface"
168e428f 613Like many MTAs, Exim has adopted the Sendmail command line interface so that it
9b371988
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614can be a straight replacement for &_/usr/lib/sendmail_& or
615&_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
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616about Sendmail in order to run Exim. For actions other than sending messages,
617Sendmail-compatible options also exist, but those that produce output (for
9b371988 618example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
168e428f 619format. There are also some additional options that are compatible with Smail
9b371988 6203, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
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621documents all Exim's command line options. This information is automatically
622made into the man page that forms part of the Exim distribution.
623
624Control of messages on the queue can be done via certain privileged command
9b371988
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625line options. There is also an optional monitor program called &'eximon'&,
626which displays current information in an X window, and which contains a menu
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627interface to Exim's command line administration options.
628
629
630
f89d2485 631.section "Terminology" "SECID9"
9b371988
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632.cindex "terminology definitions"
633.cindex "body of message" "definition of"
634The &'body'& of a message is the actual data that the sender wants to transmit.
635It is the last part of a message, and is separated from the &'header'& (see
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636below) by a blank line.
637
9b371988 638.cindex "bounce message" "definition of"
168e428f 639When a message cannot be delivered, it is normally returned to the sender in a
9b371988
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640delivery failure message or a &"non-delivery report"& (NDR). The term
641&'bounce'& is commonly used for this action, and the error reports are often
642called &'bounce messages'&. This is a convenient shorthand for &"delivery
643failure error report"&. Such messages have an empty sender address in the
644message's &'envelope'& (see below) to ensure that they cannot themselves give
645rise to further bounce messages.
646
647The term &'default'& appears frequently in this manual. It is used to qualify a
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648value which is used in the absence of any setting in the configuration. It may
649also qualify an action which is taken unless a configuration setting specifies
650otherwise.
651
9b371988 652The term &'defer'& is used when the delivery of a message to a specific
168e428f 653destination cannot immediately take place for some reason (a remote host may be
9b371988 654down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
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655until a later time.
656
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657The word &'domain'& is sometimes used to mean all but the first component of a
658host's name. It is &'not'& used in that sense here, where it normally refers to
659the part of an email address following the @ sign.
168e428f 660
f89d2485 661.cindex "envelope, definition of"
9b371988
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662.cindex "sender" "definition of"
663A message in transit has an associated &'envelope'&, as well as a header and a
168e428f
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664body. The envelope contains a sender address (to which bounce messages should
665be delivered), and any number of recipient addresses. References to the
666sender or the recipients of a message usually mean the addresses in the
667envelope. An MTA uses these addresses for delivery, and for returning bounce
668messages, not the addresses that appear in the header lines.
669
f89d2485 670.cindex "message" "header, definition of"
9b371988
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671.cindex "header section" "definition of"
672The &'header'& of a message is the first part of a message's text, consisting
673of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
674&'Subject:'&, etc. Long header lines can be split over several text lines by
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675indenting the continuations. The header is separated from the body by a blank
676line.
677
9b371988
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678.cindex "local part" "definition of"
679.cindex "domain" "definition of"
680The term &'local part'&, which is taken from RFC 2822, is used to refer to that
168e428f 681part of an email address that precedes the @ sign. The part that follows the
9b371988 682@ sign is called the &'domain'& or &'mail domain'&.
168e428f 683
9b371988 684.cindex "local delivery" "definition of"
f89d2485 685.cindex "remote delivery, definition of"
9b371988 686The terms &'local delivery'& and &'remote delivery'& are used to distinguish
168e428f 687delivery to a file or a pipe on the local host from delivery by SMTP over
068aaea8 688TCP/IP to another host. As far as Exim is concerned, all hosts other than the
9b371988 689host it is running on are &'remote'&.
168e428f 690
9b371988
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691.cindex "return path" "definition of"
692&'Return path'& is another name that is used for the sender address in a
168e428f
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693message's envelope.
694
9b371988
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695.cindex "queue" "definition of"
696The term &'queue'& is used to refer to the set of messages awaiting delivery,
168e428f
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697because this term is in widespread use in the context of MTAs. However, in
698Exim's case the reality is more like a pool than a queue, because there is
699normally no ordering of waiting messages.
700
9b371988
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701.cindex "queue runner" "definition of"
702The term &'queue runner'& is used to describe a process that scans the queue
168e428f 703and attempts to deliver those messages whose retry times have come. This term
9b371988 704is used by other MTAs, and also relates to the command &%runq%&, but in Exim
168e428f
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705the waiting messages are normally processed in an unpredictable order.
706
9b371988
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707.cindex "spool directory" "definition of"
708The term &'spool directory'& is used for a directory in which Exim keeps the
709messages on its queue &-- that is, those that it is in the process of
168e428f 710delivering. This should not be confused with the directory in which local
9b371988
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711mailboxes are stored, which is called a &"spool directory"& by some people. In
712the Exim documentation, &"spool"& is always used in the first sense.
168e428f
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713
714
715
716
717
718
9b371988
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719. ////////////////////////////////////////////////////////////////////////////
720. ////////////////////////////////////////////////////////////////////////////
168e428f 721
f89d2485 722.chapter "Incorporated code" "CHID2"
9b371988
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723.cindex "incorporated code"
724.cindex "regular expressions" "library"
725.cindex "PCRE"
168e428f
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726A number of pieces of external code are included in the Exim distribution.
727
9b371988 728.ilist
210f147e
NM
729Regular expressions are supported in the main Exim program and in the
730Exim monitor using the freely-distributable PCRE library, copyright
40df1be3
TF
731&copy; University of Cambridge. The source to PCRE is no longer shipped with
732Exim, so you will need to use the version of PCRE shipped with your system,
733or obtain and install the full version of the library from
f89d2485 734&url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
9b371988 735.next
f89d2485 736.cindex "cdb" "acknowledgment"
168e428f
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737Support for the cdb (Constant DataBase) lookup method is provided by code
738contributed by Nigel Metheringham of (at the time he contributed it) Planet
9b371988
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739Online Ltd. The implementation is completely contained within the code of Exim.
740It does not link against an external cdb library. The code contains the
741following statements:
742
743.blockquote
744Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
745
168e428f
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746This program is free software; you can redistribute it and/or modify it under
747the terms of the GNU General Public License as published by the Free Software
748Foundation; either version 2 of the License, or (at your option) any later
749version.
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750This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
751the spec and sample code for cdb can be obtained from
f89d2485
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752&url(http://www.pobox.com/~djb/cdb.html). This implementation borrows
753some code from Dan Bernstein's implementation (which has no license
754restrictions applied to it).
9b371988
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755.endblockquote
756.next
757.cindex "SPA authentication"
758.cindex "Samba project"
759.cindex "Microsoft Secure Password Authentication"
760Client support for Microsoft's &'Secure Password Authentication'& is provided
168e428f
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761by code contributed by Marc Prud'hommeaux. Server support was contributed by
762Tom Kistner. This includes code taken from the Samba project, which is released
763under the Gnu GPL.
9b371988
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764.next
765.cindex "Cyrus"
766.cindex "&'pwcheck'& daemon"
767.cindex "&'pwauthd'& daemon"
768Support for calling the Cyrus &'pwcheck'& and &'saslauthd'& daemons is provided
168e428f
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769by code taken from the Cyrus-SASL library and adapted by Alexander S.
770Sabourenkov. The permission notice appears below, in accordance with the
771conditions expressed therein.
9b371988
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772
773.blockquote
774Copyright &copy; 2001 Carnegie Mellon University. All rights reserved.
775
168e428f
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776Redistribution and use in source and binary forms, with or without
777modification, are permitted provided that the following conditions
778are met:
168e428f 779
9b371988
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780.olist
781Redistributions of source code must retain the above copyright
782notice, this list of conditions and the following disclaimer.
783.next
784Redistributions in binary form must reproduce the above copyright
168e428f
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785notice, this list of conditions and the following disclaimer in
786the documentation and/or other materials provided with the
787distribution.
9b371988
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788.next
789The name &"Carnegie Mellon University"& must not be used to
168e428f
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790endorse or promote products derived from this software without
791prior written permission. For permission or any other legal
792details, please contact
9b371988 793.display
068aaea8
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794 Office of Technology Transfer
795 Carnegie Mellon University
796 5000 Forbes Avenue
797 Pittsburgh, PA 15213-3890
798 (412) 268-4387, fax: (412) 268-7395
799 tech-transfer@andrew.cmu.edu
9b371988
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800.endd
801.next
802Redistributions of any form whatsoever must retain the following
168e428f 803acknowledgment:
9b371988
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804
805&"This product includes software developed by Computing Services
806at Carnegie Mellon University (&url(http://www.cmu.edu/computing/)."&
807
168e428f
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808CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
809THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
810AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
811FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
812WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
813AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
814OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
9b371988
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815.endlist
816.endblockquote
168e428f 817
9b371988 818.next
f89d2485 819.cindex "Exim monitor" "acknowledgment"
9b371988
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820.cindex "X-windows"
821.cindex "Athena"
168e428f
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822The Exim Monitor program, which is an X-Window application, includes
823modified versions of the Athena StripChart and TextPop widgets.
824This code is copyright by DEC and MIT, and their permission notice appears
825below, in accordance with the conditions expressed therein.
9b371988
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826
827.blockquote
168e428f
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828Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
829and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
9b371988 830
168e428f 831All Rights Reserved
9b371988 832
168e428f
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833Permission to use, copy, modify, and distribute this software and its
834documentation for any purpose and without fee is hereby granted,
835provided that the above copyright notice appear in all copies and that
836both that copyright notice and this permission notice appear in
837supporting documentation, and that the names of Digital or MIT not be
838used in advertising or publicity pertaining to distribution of the
839software without specific, written prior permission.
9b371988 840
168e428f
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841DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
842ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
843DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
844ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
845WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
846ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
847SOFTWARE.
9b371988 848.endblockquote
168e428f 849
9b371988
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850.next
851Many people have contributed code fragments, some large, some small, that were
168e428f 852not covered by any specific licence requirements. It is assumed that the
f89d2485 853contributors are happy to see their code incorporated into Exim under the GPL.
9b371988 854.endlist
168e428f
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855
856
857
858
859
9b371988
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860. ////////////////////////////////////////////////////////////////////////////
861. ////////////////////////////////////////////////////////////////////////////
168e428f 862
f89d2485 863.chapter "How Exim receives and delivers mail" "CHID11" &&&
9b371988 864 "Receiving and delivering mail"
168e428f
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865
866
f89d2485 867.section "Overall philosophy" "SECID10"
9b371988 868.cindex "design philosophy"
168e428f
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869Exim is designed to work efficiently on systems that are permanently connected
870to the Internet and are handling a general mix of mail. In such circumstances,
871most messages can be delivered immediately. Consequently, Exim does not
872maintain independent queues of messages for specific domains or hosts, though
873it does try to send several messages in a single SMTP connection after a host
874has been down, and it also maintains per-host retry information.
875
876
f89d2485 877.section "Policy control" "SECID11"
9b371988 878.cindex "policy control" "overview"
168e428f
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879Policy controls are now an important feature of MTAs that are connected to the
880Internet. Perhaps their most important job is to stop MTAs being abused as
9b371988
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881&"open relays"& by misguided individuals who send out vast amounts of
882unsolicited junk, and want to disguise its source. Exim provides flexible
883facilities for specifying policy controls on incoming mail:
168e428f 884
9b371988
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885.ilist
886.cindex "&ACL;" "introduction"
168e428f 887Exim 4 (unlike previous versions of Exim) implements policy controls on
9b371988 888incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
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889series of statements that may either grant or deny access. ACLs can be used at
890several places in the SMTP dialogue while receiving a message from a remote
9b371988
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891host. However, the most common places are after each RCPT command, and at the
892very end of the message. The sysadmin can specify conditions for accepting or
893rejecting individual recipients or the entire message, respectively, at these
894two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
168e428f 895error code.
9b371988
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896.next
897An ACL is also available for locally generated, non-SMTP messages. In this
168e428f 898case, the only available actions are to accept or deny the entire message.
9b371988
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899.next
900When Exim is compiled with the content-scanning extension, facilities are
168e428f
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901provided in the ACL mechanism for passing the message to external virus and/or
902spam scanning software. The result of such a scan is passed back to the ACL,
903which can then use it to decide what to do with the message.
9b371988
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904.next
905When a message has been received, either from a remote host or from the local
f89d2485 906host, but before the final acknowledgment has been sent, a locally supplied C
9b371988
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907function called &[local_scan()]& can be run to inspect the message and decide
908whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
909is accepted, the list of recipients can be modified by the function.
910.next
911Using the &[local_scan()]& mechanism is another way of calling external scanner
912software. The &%SA-Exim%& add-on package works this way. It does not require
913Exim to be compiled with the content-scanning extension.
914.next
915After a message has been accepted, a further checking mechanism is available in
916the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
917runs at the start of every delivery process.
918.endlist
919
920
921
f89d2485 922.section "User filters" "SECID12"
9b371988
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923.cindex "filter" "introduction"
924.cindex "Sieve filter"
168e428f 925In a conventional Exim configuration, users are able to run private filters by
9b371988
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926setting up appropriate &_.forward_& files in their home directories. See
927chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
928configuration needed to support this, and the separate document entitled
929&'Exim's interfaces to mail filtering'& for user details. Two different kinds
930of filtering are available:
931
932.ilist
933Sieve filters are written in the standard filtering language that is defined
168e428f 934by RFC 3028.
9b371988
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935.next
936Exim filters are written in a syntax that is unique to Exim, but which is more
168e428f 937powerful than Sieve, which it pre-dates.
9b371988 938.endlist
168e428f
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939
940User filters are run as part of the routing process, described below.
941
942
943
9b371988
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944.section "Message identification" "SECTmessiden"
945.cindex "message ids" "details of format"
946.cindex "format" "of message id"
947.cindex "id of message"
948.cindex "base62"
949.cindex "base36"
950.cindex "Darwin"
951.cindex "Cygwin"
952Every message handled by Exim is given a &'message id'& which is sixteen
168e428f 953characters long. It is divided into three parts, separated by hyphens, for
9b371988 954example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
168e428f
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955normally encoding numbers in base 62. However, in the Darwin operating
956system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
957(avoiding the use of lower case letters) is used instead, because the message
958id is used to construct file names, and the names of files in those systems are
068aaea8 959not always case-sensitive.
168e428f 960
9b371988 961.cindex "pid (process id)" "re-use of"
168e428f
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962The detail of the contents of the message id have changed as Exim has evolved.
963Earlier versions relied on the operating system not re-using a process id (pid)
964within one second. On modern operating systems, this assumption can no longer
965be made, so the algorithm had to be changed. To retain backward compatibility,
966the format of the message id was retained, which is why the following rules are
967somewhat eccentric:
968
9b371988
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969.ilist
970The first six characters of the message id are the time at which the message
168e428f
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971started to be received, to a granularity of one second. That is, this field
972contains the number of seconds since the start of the epoch (the normal Unix
973way of representing the date and time of day).
9b371988
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974.next
975After the first hyphen, the next six characters are the id of the process that
168e428f 976received the message.
9b371988
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977.next
978There are two different possibilities for the final two characters:
979.olist
0a4e3112 980.oindex "&%localhost_number%&"
9b371988 981If &%localhost_number%& is not set, this value is the fractional part of the
168e428f
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982time of reception, normally in units of 1/2000 of a second, but for systems
983that must use base 36 instead of base 62 (because of case-insensitive file
984systems), the units are 1/1000 of a second.
9b371988
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985.next
986If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
168e428f
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987the fractional part of the time, which in this case is in units of 1/200
988(1/100) of a second.
9b371988
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989.endlist
990.endlist
168e428f
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991
992After a message has been received, Exim waits for the clock to tick at the
993appropriate resolution before proceeding, so that if another message is
994received by the same process, or by another process with the same (re-used)
995pid, it is guaranteed that the time will be different. In most cases, the clock
996will already have ticked while the message was being received.
997
998
f89d2485 999.section "Receiving mail" "SECID13"
9b371988
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1000.cindex "receiving mail"
1001.cindex "message" "reception"
068aaea8
PH
1002The only way Exim can receive mail from another host is using SMTP over
1003TCP/IP, in which case the sender and recipient addresses are transferred using
168e428f
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1004SMTP commands. However, from a locally running process (such as a user's MUA),
1005there are several possibilities:
1006
9b371988
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1007.ilist
1008If the process runs Exim with the &%-bm%& option, the message is read
168e428f 1009non-interactively (usually via a pipe), with the recipients taken from the
9b371988
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1010command line, or from the body of the message if &%-t%& is also used.
1011.next
1012If the process runs Exim with the &%-bS%& option, the message is also read
168e428f
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1013non-interactively, but in this case the recipients are listed at the start of
1014the message in a series of SMTP RCPT commands, terminated by a DATA
9b371988 1015command. This is so-called &"batch SMTP"& format,
168e428f
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1016but it isn't really SMTP. The SMTP commands are just another way of passing
1017envelope addresses in a non-interactive submission.
9b371988
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1018.next
1019If the process runs Exim with the &%-bs%& option, the message is read
168e428f
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1020interactively, using the SMTP protocol. A two-way pipe is normally used for
1021passing data between the local process and the Exim process.
9b371988 1022This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
168e428f 1023example, the ACLs for SMTP commands are used for this form of submission.
9b371988
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1024.next
1025A local process may also make a TCP/IP call to the host's loopback address
168e428f
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1026(127.0.0.1) or any other of its IP addresses. When receiving messages, Exim
1027does not treat the loopback address specially. It treats all such connections
1028in the same way as connections from other hosts.
9b371988 1029.endlist
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1030
1031
f89d2485 1032.cindex "message sender, constructed by Exim"
9b371988 1033.cindex "sender" "constructed by Exim"
168e428f
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1034In the three cases that do not involve TCP/IP, the sender address is
1035constructed from the login name of the user that called Exim and a default
9b371988 1036qualification domain (which can be set by the &%qualify_domain%& configuration
168e428f
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1037option). For local or batch SMTP, a sender address that is passed using the
1038SMTP MAIL command is ignored. However, the system administrator may allow
9b371988 1039certain users (&"trusted users"&) to specify a different sender address
168e428f 1040unconditionally, or all users to specify certain forms of different sender
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1041address. The &%-f%& option or the SMTP MAIL command is used to specify these
1042different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1043users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
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1044users to change sender addresses.
1045
1046Messages received by either of the non-interactive mechanisms are subject to
1047checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1048(either over TCP/IP, or interacting with a local process) can be checked by a
1049number of ACLs that operate at different times during the SMTP session. Either
1050individual recipients, or the entire message, can be rejected if local policy
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1051requirements are not met. The &[local_scan()]& function (see chapter
1052&<<CHAPlocalscan>>&) is run for all incoming messages.
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1053
1054Exim can be configured not to start a delivery process when a message is
1055received; this can be unconditional, or depend on the number of incoming SMTP
1056connections or the system load. In these situations, new messages wait on the
1057queue until a queue runner process picks them up. However, in standard
1058configurations under normal conditions, delivery is started as soon as a
1059message is received.
1060
1061
1062
1063
1064
f89d2485 1065.section "Handling an incoming message" "SECID14"
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1066.cindex "spool directory" "files that hold a message"
1067.cindex "file" "how a message is held"
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1068When Exim accepts a message, it writes two files in its spool directory. The
1069first contains the envelope information, the current status of the message, and
1070the header lines, and the second contains the body of the message. The names of
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1071the two spool files consist of the message id, followed by &`-H`& for the
1072file containing the envelope and header, and &`-D`& for the data file.
168e428f 1073
9b371988 1074.cindex "spool directory" "&_input_& sub-directory"
168e428f 1075By default all these message files are held in a single directory called
9b371988 1076&_input_& inside the general Exim spool directory. Some operating systems do
c0712871 1077not perform very well if the number of files in a directory gets large; to
9b371988 1078improve performance in such cases, the &%split_spool_directory%& option can be
168e428f 1079used. This causes Exim to split up the input files into 62 sub-directories
db9452a9 1080whose names are single letters or digits. When this is done, the queue is
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1081processed one sub-directory at a time instead of all at once, which can improve
1082overall performance even when there are not enough files in each directory to
db9452a9 1083affect file system performance.
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1084
1085The envelope information consists of the address of the message's sender and
1086the addresses of the recipients. This information is entirely separate from
1087any addresses contained in the header lines. The status of the message includes
1088a list of recipients who have already received the message. The format of the
9b371988 1089first spool file is described in chapter &<<CHAPspool>>&.
168e428f 1090
9b371988 1091.cindex "rewriting" "addresses"
168e428f 1092Address rewriting that is specified in the rewrite section of the configuration
9b371988 1093(see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
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1094both in the header lines and the envelope, at the time the message is accepted.
1095If during the course of delivery additional addresses are generated (for
1096example, via aliasing), these new addresses are rewritten as soon as they are
1097generated. At the time a message is actually delivered (transported) further
1098rewriting can take place; because this is a transport option, it can be
1099different for different forms of delivery. It is also possible to specify the
1100addition or removal of certain header lines at the time the message is
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1101delivered (see chapters &<<CHAProutergeneric>>& and
1102&<<CHAPtransportgeneric>>&).
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1103
1104
1105
f89d2485 1106.section "Life of a message" "SECID15"
9b371988
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1107.cindex "message" "life of"
1108.cindex "message" "frozen"
168e428f
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1109A message remains in the spool directory until it is completely delivered to
1110its recipients or to an error address, or until it is deleted by an
1111administrator or by the user who originally created it. In cases when delivery
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1112cannot proceed &-- for example, when a message can neither be delivered to its
1113recipients nor returned to its sender, the message is marked &"frozen"& on the
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1114spool, and no more deliveries are attempted.
1115
9b371988
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1116.cindex "frozen messages" "thawing"
1117.cindex "message" "thawing frozen"
1118An administrator can &"thaw"& such messages when the problem has been
1119corrected, and can also freeze individual messages by hand if necessary. In
1120addition, an administrator can force a delivery error, causing a bounce message
1121to be sent.
1122
0a4e3112
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1123.oindex "&%timeout_frozen_after%&"
1124.oindex "&%ignore_bounce_errors_after%&"
9b371988
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1125There are options called &%ignore_bounce_errors_after%& and
1126&%timeout_frozen_after%&, which discard frozen messages after a certain time.
068aaea8 1127The first applies only to frozen bounces, the second to any frozen messages.
168e428f 1128
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1129.cindex "message" "log file for"
1130.cindex "log" "file for each message"
168e428f 1131While Exim is working on a message, it writes information about each delivery
068aaea8 1132attempt to its main log file. This includes successful, unsuccessful, and
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1133delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1134lines are also written to a separate &'message log'& file for each message.
1135These logs are solely for the benefit of the administrator, and are normally
1136deleted along with the spool files when processing of a message is complete.
168e428f 1137The use of individual message logs can be disabled by setting
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1138&%no_message_logs%&; this might give an improvement in performance on very busy
1139systems.
168e428f 1140
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1141.cindex "journal file"
1142.cindex "file" "journal"
168e428f
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1143All the information Exim itself needs to set up a delivery is kept in the first
1144spool file, along with the header lines. When a successful delivery occurs, the
1145address is immediately written at the end of a journal file, whose name is the
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1146message id followed by &`-J`&. At the end of a delivery run, if there are some
1147addresses left to be tried again later, the first spool file (the &`-H`& file)
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1148is updated to indicate which these are, and the journal file is then deleted.
1149Updating the spool file is done by writing a new file and renaming it, to
1150minimize the possibility of data loss.
1151
1152Should the system or the program crash after a successful delivery but before
1153the spool file has been updated, the journal is left lying around. The next
1154time Exim attempts to deliver the message, it reads the journal file and
1155updates the spool file before proceeding. This minimizes the chances of double
1156deliveries caused by crashes.
1157
1158
1159
9b371988
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1160.section "Processing an address for delivery" "SECTprocaddress"
1161.cindex "drivers" "definition of"
1162.cindex "router" "definition of"
1163.cindex "transport" "definition of"
1164The main delivery processing elements of Exim are called &'routers'& and
1165&'transports'&, and collectively these are known as &'drivers'&. Code for a
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1166number of them is provided in the source distribution, and compile-time options
1167specify which ones are included in the binary. Run time options specify which
1168ones are actually used for delivering messages.
1169
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1170.cindex "drivers" "instance definition"
1171Each driver that is specified in the run time configuration is an &'instance'&
168e428f 1172of that particular driver type. Multiple instances are allowed; for example,
9b371988 1173you can set up several different &(smtp)& transports, each with different
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1174option values that might specify different ports or different timeouts. Each
1175instance has its own identifying name. In what follows we will normally use the
1176instance name when discussing one particular instance (that is, one specific
1177configuration of the driver), and the generic driver name when discussing
1178the driver's features in general.
1179
9b371988 1180A &'router'& is a driver that operates on an address, either determining how
068aaea8 1181its delivery should happen, by assigning it to a specific transport, or
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1182converting the address into one or more new addresses (for example, via an
1183alias file). A router may also explicitly choose to fail an address, causing it
1184to be bounced.
1185
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1186A &'transport'& is a driver that transmits a copy of the message from Exim's
1187spool to some destination. There are two kinds of transport: for a &'local'&
168e428f 1188transport, the destination is a file or a pipe on the local host, whereas for a
9b371988 1189&'remote'& transport the destination is some other host. A message is passed
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1190to a specific transport as a result of successful routing. If a message has
1191several recipients, it may be passed to a number of different transports.
1192
9b371988 1193.cindex "preconditions" "definition of"
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1194An address is processed by passing it to each configured router instance in
1195turn, subject to certain preconditions, until a router accepts the address or
1196specifies that it should be bounced. We will describe this process in more
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1197detail shortly. First, as a simple example, we consider how each recipient
1198address in a message is processed in a small configuration of three routers.
168e428f 1199
068aaea8 1200To make this a more concrete example, it is described in terms of some actual
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1201routers, but remember, this is only an example. You can configure Exim's
1202routers in many different ways, and there may be any number of routers in a
1203configuration.
1204
1205The first router that is specified in a configuration is often one that handles
1206addresses in domains that are not recognized specially by the local host. These
1207are typically addresses for arbitrary domains on the Internet. A precondition
1208is set up which looks for the special domains known to the host (for example,
9b371988 1209its own domain name), and the router is run for addresses that do &'not'&
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1210match. Typically, this is a router that looks up domains in the DNS in order to
1211find the hosts to which this address routes. If it succeeds, the address is
068aaea8 1212assigned to a suitable SMTP transport; if it does not succeed, the router is
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1213configured to fail the address.
1214
068aaea8 1215The second router is reached only when the domain is recognized as one that
9b371988 1216&"belongs"& to the local host. This router does redirection &-- also known as
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1217aliasing and forwarding. When it generates one or more new addresses from the
1218original, each of them is routed independently from the start. Otherwise, the
1219router may cause an address to fail, or it may simply decline to handle the
1220address, in which case the address is passed to the next router.
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1221
1222The final router in many configurations is one that checks to see if the
1223address belongs to a local mailbox. The precondition may involve a check to
1224see if the local part is the name of a login account, or it may look up the
1225local part in a file or a database. If its preconditions are not met, or if
1226the router declines, we have reached the end of the routers. When this happens,
1227the address is bounced.
1228
1229
1230
f89d2485 1231.section "Processing an address for verification" "SECID16"
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1232.cindex "router" "for verification"
1233.cindex "verifying address" "overview"
168e428f 1234As well as being used to decide how to deliver to an address, Exim's routers
9b371988 1235are also used for &'address verification'&. Verification can be requested as
168e428f 1236one of the checks to be performed in an ACL for incoming messages, on both
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1237sender and recipient addresses, and it can be tested using the &%-bv%& and
1238&%-bvs%& command line options.
168e428f 1239
9b371988 1240When an address is being verified, the routers are run in &"verify mode"&. This
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1241does not affect the way the routers work, but it is a state that can be
1242detected. By this means, a router can be skipped or made to behave differently
1243when verifying. A common example is a configuration in which the first router
1244sends all messages to a message-scanning program, unless they have been
1245previously scanned. Thus, the first router accepts all addresses without any
9b371988 1246checking, making it useless for verifying. Normally, the &%no_verify%& option
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1247would be set for such a router, causing it to be skipped in verify mode.
1248
1249
1250
1251
9b371988
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1252.section "Running an individual router" "SECTrunindrou"
1253.cindex "router" "running details"
1254.cindex "preconditions" "checking"
1255.cindex "router" "result of running"
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1256As explained in the example above, a number of preconditions are checked before
1257running a router. If any are not met, the router is skipped, and the address is
9b371988 1258passed to the next router. When all the preconditions on a router &'are'& met,
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1259the router is run. What happens next depends on the outcome, which is one of
1260the following:
1261
9b371988
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1262.ilist
1263&'accept'&: The router accepts the address, and either assigns it to a
1264transport, or generates one or more &"child"& addresses. Processing the
1265original address ceases,
0a4e3112 1266.oindex "&%unseen%&"
9b371988 1267unless the &%unseen%& option is set on the router. This option
168e428f 1268can be used to set up multiple deliveries with different routing (for example,
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1269for keeping archive copies of messages). When &%unseen%& is set, the address is
1270passed to the next router. Normally, however, an &'accept'& return marks the
168e428f 1271end of routing.
9b371988 1272
068aaea8
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1273Any child addresses generated by the router are processed independently,
1274starting with the first router by default. It is possible to change this by
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1275setting the &%redirect_router%& option to specify which router to start at for
1276child addresses. Unlike &%pass_router%& (see below) the router specified by
1277&%redirect_router%& may be anywhere in the router configuration.
1278.next
1279&'pass'&: The router recognizes the address, but cannot handle it itself. It
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1280requests that the address be passed to another router. By default the address
1281is passed to the next router, but this can be changed by setting the
9b371988 1282&%pass_router%& option. However, (unlike &%redirect_router%&) the named router
168e428f 1283must be below the current router (to avoid loops).
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1284.next
1285&'decline'&: The router declines to accept the address because it does not
168e428f 1286recognize it at all. By default, the address is passed to the next router, but
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1287this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1288set, all the remaining routers are skipped. In effect, &%no_more%& converts
1289&'decline'& into &'fail'&.
1290.next
1291&'fail'&: The router determines that the address should fail, and queues it for
168e428f 1292the generation of a bounce message. There is no further processing of the
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1293original address unless &%unseen%& is set on the router.
1294.next
1295&'defer'&: The router cannot handle the address at the present time. (A
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1296database may be offline, or a DNS lookup may have timed out.) No further
1297processing of the address happens in this delivery attempt. It is tried again
1298next time the message is considered for delivery.
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1299.next
1300&'error'&: There is some error in the router (for example, a syntax error in
168e428f 1301its configuration). The action is as for defer.
9b371988 1302.endlist
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1303
1304If an address reaches the end of the routers without having been accepted by
068aaea8 1305any of them, it is bounced as unrouteable. The default error message in this
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1306situation is &"unrouteable address"&, but you can set your own message by
1307making use of the &%cannot_route_message%& option. This can be set for any
1308router; the value from the last router that &"saw"& the address is used.
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1309
1310Sometimes while routing you want to fail a delivery when some conditions are
1311met but others are not, instead of passing the address on for further routing.
1312You can do this by having a second router that explicitly fails the delivery
9b371988 1313when the relevant conditions are met. The &(redirect)& router has a &"fail"&
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1314facility for this purpose.
1315
1316
f89d2485 1317.section "Duplicate addresses" "SECID17"
9b371988 1318.cindex "case of local parts"
f89d2485 1319.cindex "address duplicate, discarding"
db9452a9 1320.cindex "duplicate addresses"
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1321Once routing is complete, Exim scans the addresses that are assigned to local
1322and remote transports, and discards any duplicates that it finds. During this
3cb1b51e 1323check, local parts are treated as case-sensitive. This happens only when
db9452a9 1324actually delivering a message; when testing routers with &%-bt%&, all the
3cb1b51e 1325routed addresses are shown.
db9452a9 1326
068aaea8 1327
168e428f 1328
9b371988 1329.section "Router preconditions" "SECTrouprecon"
f89d2485 1330.cindex "router" "preconditions, order of processing"
9b371988 1331.cindex "preconditions" "order of processing"
168e428f
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1332The preconditions that are tested for each router are listed below, in the
1333order in which they are tested. The individual configuration options are
9b371988 1334described in more detail in chapter &<<CHAProutergeneric>>&.
168e428f 1335
9b371988
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1336.ilist
1337The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
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1338the local parts handled by the router may or must have certain prefixes and/or
1339suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1340skipped. These conditions are tested first. When an affix is present, it is
1341removed from the local part before further processing, including the evaluation
1342of any other conditions.
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1343.next
1344Routers can be designated for use only when not verifying an address, that is,
168e428f 1345only when routing it for delivery (or testing its delivery routing). If the
9b371988 1346&%verify%& option is set false, the router is skipped when Exim is verifying an
168e428f 1347address.
9b371988
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1348Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1349&%verify_recipient%&, which independently control the use of the router for
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1350sender and recipient verification. You can set these options directly if
1351you want a router to be used for only one type of verification.
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1352.next
1353If the &%address_test%& option is set false, the router is skipped when Exim is
1354run with the &%-bt%& option to test an address routing. This can be helpful
1355when the first router sends all new messages to a scanner of some sort; it
1356makes it possible to use &%-bt%& to test subsequent delivery routing without
1357having to simulate the effect of the scanner.
1358.next
1359Routers can be designated for use only when verifying an address, as
1360opposed to routing it for delivery. The &%verify_only%& option controls this.
1361.next
1362Individual routers can be explicitly skipped when running the routers to
1363check an address given in the SMTP EXPN command (see the &%expn%& option).
1364.next
1365If the &%domains%& option is set, the domain of the address must be in the set
068aaea8 1366of domains that it defines.
9b371988 1367.next
f89d2485
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1368.vindex "&$local_part_prefix$&"
1369.vindex "&$local_part$&"
1370.vindex "&$local_part_suffix$&"
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1371If the &%local_parts%& option is set, the local part of the address must be in
1372the set of local parts that it defines. If &%local_part_prefix%& or
1373&%local_part_suffix%& is in use, the prefix or suffix is removed from the local
168e428f 1374part before this check. If you want to do precondition tests on local parts
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1375that include affixes, you can do so by using a &%condition%& option (see below)
1376that uses the variables &$local_part$&, &$local_part_prefix$&, and
1377&$local_part_suffix$& as necessary.
1378.next
f89d2485
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1379.vindex "&$local_user_uid$&"
1380.vindex "&$local_user_gid$&"
1381.vindex "&$home$&"
9b371988 1382If the &%check_local_user%& option is set, the local part must be the name of
068aaea8 1383an account on the local host. If this check succeeds, the uid and gid of the
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1384local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1385user's home directory is placed in &$home$&; these values can be used in the
1386remaining preconditions.
1387.next
1388If the &%router_home_directory%& option is set, it is expanded at this point,
1389because it overrides the value of &$home$&. If this expansion were left till
1390later, the value of &$home$& as set by &%check_local_user%& would be used in
1391subsequent tests. Having two different values of &$home$& in the same router
168e428f 1392could lead to confusion.
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1393.next
1394If the &%senders%& option is set, the envelope sender address must be in the
1395set of addresses that it defines.
1396.next
1397If the &%require_files%& option is set, the existence or non-existence of
168e428f 1398specified files is tested.
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1399.next
1400.cindex "customizing" "precondition"
1401If the &%condition%& option is set, it is evaluated and tested. This option
1402uses an expanded string to allow you to set up your own custom preconditions.
1403Expanded strings are described in chapter &<<CHAPexpand>>&.
1404.endlist
168e428f 1405
168e428f 1406
9b371988
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1407Note that &%require_files%& comes near the end of the list, so you cannot use
1408it to check for the existence of a file in which to lookup up a domain, local
168e428f 1409part, or sender. However, as these options are all expanded, you can use the
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1410&%exists%& expansion condition to make such tests within each condition. The
1411&%require_files%& option is intended for checking files that the router may be
168e428f 1412going to use internally, or which are needed by a specific transport (for
9b371988 1413example, &_.procmailrc_&).
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1414
1415
1416
f89d2485 1417.section "Delivery in detail" "SECID18"
9b371988 1418.cindex "delivery" "in detail"
168e428f
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1419When a message is to be delivered, the sequence of events is as follows:
1420
9b371988
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1421.ilist
1422If a system-wide filter file is specified, the message is passed to it. The
168e428f
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1423filter may add recipients to the message, replace the recipients, discard the
1424message, cause a new message to be generated, or cause the message delivery to
1425fail. The format of the system filter file is the same as for Exim user filter
9b371988
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1426files, described in the separate document entitled &'Exim's interfaces to mail
1427filtering'&.
1428.cindex "Sieve filter" "not available for system filter"
1429(&*Note*&: Sieve cannot be used for system filter files.)
1430
1431Some additional features are available in system filters &-- see chapter
1432&<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
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1433filter only once per delivery attempt, however many recipients it has. However,
1434if there are several delivery attempts because one or more addresses could not
1435be immediately delivered, the system filter is run each time. The filter
9b371988 1436condition &%first_delivery%& can be used to detect the first run of the system
168e428f 1437filter.
9b371988
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1438.next
1439Each recipient address is offered to each configured router in turn, subject to
1440its preconditions, until one is able to handle it. If no router can handle the
1441address, that is, if they all decline, the address is failed. Because routers
1442can be targeted at particular domains, several locally handled domains can be
1443processed entirely independently of each other.
1444.next
1445.cindex "routing" "loops in"
1446.cindex "loop" "while routing"
1447A router that accepts an address may assign it to a local or a remote
1448transport. However, the transport is not run at this time. Instead, the address
1449is placed on a list for the particular transport, which will be run later.
068aaea8
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1450Alternatively, the router may generate one or more new addresses (typically
1451from alias, forward, or filter files). New addresses are fed back into this
1452process from the top, but in order to avoid loops, a router ignores any address
1453which has an identically-named ancestor that was processed by itself.
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1454.next
1455When all the routing has been done, addresses that have been successfully
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1456handled are passed to their assigned transports. When local transports are
1457doing real local deliveries, they handle only one address at a time, but if a
1458local transport is being used as a pseudo-remote transport (for example, to
1459collect batched SMTP messages for transmission by some other means) multiple
1460addresses can be handled. Remote transports can always handle more than one
1461address at a time, but can be configured not to do so, or to restrict multiple
1462addresses to the same domain.
9b371988
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1463.next
1464Each local delivery to a file or a pipe runs in a separate process under a
168e428f
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1465non-privileged uid, and these deliveries are run one at a time. Remote
1466deliveries also run in separate processes, normally under a uid that is private
9b371988 1467to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
168e428f 1468run in parallel. The maximum number of simultaneous remote deliveries for any
9b371988 1469one message is set by the &%remote_max_parallel%& option.
168e428f
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1470The order in which deliveries are done is not defined, except that all local
1471deliveries happen before any remote deliveries.
9b371988
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1472.next
1473.cindex "queue runner"
168e428f
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1474When it encounters a local delivery during a queue run, Exim checks its retry
1475database to see if there has been a previous temporary delivery failure for the
1476address before running the local transport. If there was a previous failure,
1477Exim does not attempt a new delivery until the retry time for the address is
1478reached. However, this happens only for delivery attempts that are part of a
1479queue run. Local deliveries are always attempted when delivery immediately
1480follows message reception, even if retry times are set for them. This makes for
1481better behaviour if one particular message is causing problems (for example,
1482causing quota overflow, or provoking an error in a filter file).
9b371988
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1483.next
1484.cindex "delivery" "retry in remote transports"
168e428f
PH
1485Remote transports do their own retry handling, since an address may be
1486deliverable to one of a number of hosts, each of which may have a different
1487retry time. If there have been previous temporary failures and no host has
1488reached its retry time, no delivery is attempted, whether in a queue run or
9b371988
PH
1489not. See chapter &<<CHAPretry>>& for details of retry strategies.
1490.next
1491If there were any permanent errors, a bounce message is returned to an
168e428f
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1492appropriate address (the sender in the common case), with details of the error
1493for each failing address. Exim can be configured to send copies of bounce
1494messages to other addresses.
9b371988
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1495.next
1496.cindex "delivery" "deferral"
168e428f
PH
1497If one or more addresses suffered a temporary failure, the message is left on
1498the queue, to be tried again later. Delivery of these addresses is said to be
9b371988
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1499&'deferred'&.
1500.next
1501When all the recipient addresses have either been delivered or bounced,
168e428f
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1502handling of the message is complete. The spool files and message log are
1503deleted, though the message log can optionally be preserved if required.
9b371988 1504.endlist
168e428f
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1505
1506
1507
1508
f89d2485 1509.section "Retry mechanism" "SECID19"
9b371988
PH
1510.cindex "delivery" "retry mechanism"
1511.cindex "retry" "description of mechanism"
1512.cindex "queue runner"
168e428f
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1513Exim's mechanism for retrying messages that fail to get delivered at the first
1514attempt is the queue runner process. You must either run an Exim daemon that
9b371988
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1515uses the &%-q%& option with a time interval to start queue runners at regular
1516intervals, or use some other means (such as &'cron'&) to start them. If you do
168e428f
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1517not arrange for queue runners to be run, messages that fail temporarily at the
1518first attempt will remain on your queue for ever. A queue runner process works
068aaea8 1519its way through the queue, one message at a time, trying each delivery that has
168e428f
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1520passed its retry time.
1521You can run several queue runners at once.
1522
1523Exim uses a set of configured rules to determine when next to retry the failing
9b371988
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1524address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1525should give up trying to deliver to the address, at which point it generates a
1526bounce message. If no retry rules are set for a particular host, address, and
1527error combination, no retries are attempted, and temporary errors are treated
1528as permanent.
168e428f
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1529
1530
1531
f89d2485 1532.section "Temporary delivery failure" "SECID20"
9b371988 1533.cindex "delivery" "temporary failure"
168e428f
PH
1534There are many reasons why a message may not be immediately deliverable to a
1535particular address. Failure to connect to a remote machine (because it, or the
1536connection to it, is down) is one of the most common. Temporary failures may be
1537detected during routing as well as during the transport stage of delivery.
1538Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1539is on a file system where the user is over quota. Exim can be configured to
1540impose its own quotas on local mailboxes; where system quotas are set they will
1541also apply.
1542
1543If a host is unreachable for a period of time, a number of messages may be
1544waiting for it by the time it recovers, and sending them in a single SMTP
1545connection is clearly beneficial. Whenever a delivery to a remote host is
1546deferred,
1547
9b371988 1548.cindex "hints database"
168e428f
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1549Exim makes a note in its hints database, and whenever a successful
1550SMTP delivery has happened, it looks to see if any other messages are waiting
1551for the same host. If any are found, they are sent over the same SMTP
1552connection, subject to a configuration limit as to the maximum number in any
1553one connection.
1554
1555
1556
1557
f89d2485 1558.section "Permanent delivery failure" "SECID21"
9b371988
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1559.cindex "delivery" "permanent failure"
1560.cindex "bounce message" "when generated"
168e428f
PH
1561When a message cannot be delivered to some or all of its intended recipients, a
1562bounce message is generated. Temporary delivery failures turn into permanent
1563errors when their timeout expires. All the addresses that fail in a given
1564delivery attempt are listed in a single message. If the original message has
1565many recipients, it is possible for some addresses to fail in one delivery
1566attempt and others to fail subsequently, giving rise to more than one bounce
1567message. The wording of bounce messages can be customized by the administrator.
9b371988 1568See chapter &<<CHAPemsgcust>>& for details.
168e428f 1569
9b371988
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1570.cindex "&'X-Failed-Recipients:'& header line"
1571Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
168e428f
PH
1572failed addresses, for the benefit of programs that try to analyse such messages
1573automatically.
1574
9b371988 1575.cindex "bounce message" "recipient of"
168e428f
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1576A bounce message is normally sent to the sender of the original message, as
1577obtained from the message's envelope. For incoming SMTP messages, this is the
9b371988
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1578address given in the MAIL command. However, when an address is expanded via a
1579forward or alias file, an alternative address can be specified for delivery
1580failures of the generated addresses. For a mailing list expansion (see section
1581&<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1582of the list.
168e428f
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1583
1584
1585
f89d2485 1586.section "Failures to deliver bounce messages" "SECID22"
9b371988 1587.cindex "bounce message" "failure to deliver"
168e428f
PH
1588If a bounce message (either locally generated or received from a remote host)
1589itself suffers a permanent delivery failure, the message is left on the queue,
1590but it is frozen, awaiting the attention of an administrator. There are options
068aaea8 1591that can be used to make Exim discard such failed messages, or to keep them
9b371988
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1592for only a short time (see &%timeout_frozen_after%& and
1593&%ignore_bounce_errors_after%&).
168e428f
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1594
1595
1596
1597
1598
9b371988
PH
1599. ////////////////////////////////////////////////////////////////////////////
1600. ////////////////////////////////////////////////////////////////////////////
168e428f 1601
f89d2485 1602.chapter "Building and installing Exim" "CHID3"
4f578862 1603.scindex IIDbuex "building Exim"
168e428f 1604
f89d2485
PH
1605.section "Unpacking" "SECID23"
1606Exim is distributed as a gzipped or bzipped tar file which, when unpacked,
168e428f 1607creates a directory with the name of the current release (for example,
9b371988
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1608&_exim-&version;_&) into which the following files are placed:
1609
1610.table2 140pt
f89d2485
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1611.irow &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1612.irow &_CHANGES_& "contains a reference to where changes are &&&
1613 documented"
1614.irow &_LICENCE_& "the GNU General Public Licence"
1615.irow &_Makefile_& "top-level make file"
1616.irow &_NOTICE_& "conditions for the use of Exim"
1617.irow &_README_& "list of files, directories and simple build &&&
1618 instructions"
9b371988
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1619.endtable
1620
1621Other files whose names begin with &_README_& may also be present. The
168e428f
PH
1622following subdirectories are created:
1623
9b371988 1624.table2 140pt
f89d2485
PH
1625.irow &_Local_& "an empty directory for local configuration files"
1626.irow &_OS_& "OS-specific files"
1627.irow &_doc_& "documentation files"
1628.irow &_exim_monitor_& "source files for the Exim monitor"
1629.irow &_scripts_& "scripts used in the build process"
1630.irow &_src_& "remaining source files"
1631.irow &_util_& "independent utilities"
9b371988
PH
1632.endtable
1633
1634The main utility programs are contained in the &_src_& directory, and are built
1635with the Exim binary. The &_util_& directory contains a few optional scripts
168e428f
PH
1636that may be useful to some sites.
1637
1638
f89d2485 1639.section "Multiple machine architectures and operating systems" "SECID24"
9b371988 1640.cindex "building Exim" "multiple OS/architectures"
168e428f
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1641The building process for Exim is arranged to make it easy to build binaries for
1642a number of different architectures and operating systems from the same set of
9b371988
PH
1643source files. Compilation does not take place in the &_src_& directory.
1644Instead, a &'build directory'& is created for each architecture and operating
1645system.
1646.cindex "symbolic link" "to build directory"
168e428f 1647Symbolic links to the sources are installed in this directory, which is where
9b371988
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1648the actual building takes place. In most cases, Exim can discover the machine
1649architecture and operating system for itself, but the defaults can be
1650overridden if necessary.
168e428f 1651
168e428f 1652
8473d4ee 1653.section "PCRE library" "SECTpcre"
210f147e
NM
1654.cindex "PCRE library"
1655Exim no longer has an embedded PCRE library as the vast majority of
1656modern systems include PCRE as a system library, although you may need
1657to install the PCRE or PCRE development package for your operating
1658system. If your system has a normal PCRE installation the Exim build
1659process will need no further configuration. If the library or the
1660headers are in an unusual location you will need to set the PCRE_LIBS
1661and INCLUDE directives appropriately. If your operating system has no
1662PCRE support then you will need to obtain and build the current PCRE
1663from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/).
1664
9b371988
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1665.section "DBM libraries" "SECTdb"
1666.cindex "DBM libraries" "discussion of"
1667.cindex "hints database" "DBM files used for"
168e428f
PH
1668Even if you do not use any DBM files in your configuration, Exim still needs a
1669DBM library in order to operate, because it uses indexed files for its hints
1670databases. Unfortunately, there are a number of DBM libraries in existence, and
1671different operating systems often have different ones installed.
1672
9b371988 1673.cindex "Solaris" "DBM library for"
f89d2485
PH
1674.cindex "IRIX, DBM library for"
1675.cindex "BSD, DBM library for"
1676.cindex "Linux, DBM library for"
168e428f
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1677If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1678Linux distribution, the DBM configuration should happen automatically, and you
1679may be able to ignore this section. Otherwise, you may have to learn more than
1680you would like about DBM libraries from what follows.
1681
9b371988 1682.cindex "&'ndbm'& DBM library"
168e428f 1683Licensed versions of Unix normally contain a library of DBM functions operating
9b371988 1684via the &'ndbm'& interface, and this is what Exim expects by default. Free
168e428f
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1685versions of Unix seem to vary in what they contain as standard. In particular,
1686some early versions of Linux have no default DBM library, and different
1687distributors have chosen to bundle different libraries with their packaged
f89d2485 1688versions. However, the more recent releases seem to have standardized on the
168e428f
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1689Berkeley DB library.
1690
1691Different DBM libraries have different conventions for naming the files they
9b371988 1692use. When a program opens a file called &_dbmfile_&, there are several
168e428f
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1693possibilities:
1694
9b371988
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1695.olist
1696A traditional &'ndbm'& implementation, such as that supplied as part of
1697Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1698.next
1699.cindex "&'gdbm'& DBM library"
1700The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
168e428f 1701compatibility interface it makes two different hard links to it with names
9b371988 1702&_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
168e428f 1703file name is used unmodified.
9b371988
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1704.next
1705.cindex "Berkeley DB library"
1706The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1707operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1708programmer exactly the same as the traditional &'ndbm'& implementation.
1709.next
1710If the Berkeley package is used in its native mode, it operates on a single
1711file called &_dbmfile_&; the programmer's interface is somewhat different to
1712the traditional &'ndbm'& interface.
1713.next
1714To complicate things further, there are several very different versions of the
168e428f 1715Berkeley DB package. Version 1.85 was stable for a very long time, releases
9b371988
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17162.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1717numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
168e428f 1718versions of Berkeley DB can be obtained from
9b371988
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1719&url(http://www.sleepycat.com/).
1720.next
1721.cindex "&'tdb'& DBM library"
1722Yet another DBM library, called &'tdb'&, is available from
1723&url(http://download.sourceforge.net/tdb). It has its own interface, and also
1724operates on a single file.
1725.endlist
1726
1727.cindex "USE_DB"
1728.cindex "DBM libraries" "configuration for building"
168e428f
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1729Exim and its utilities can be compiled to use any of these interfaces. In order
1730to use any version of the Berkeley DB package in native mode, you must set
1731USE_DB in an appropriate configuration file (typically
9b371988
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1732&_Local/Makefile_&). For example:
1733.code
1734USE_DB=yes
1735.endd
168e428f
PH
1736Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1737error is diagnosed if you set more than one of these.
1738
1739At the lowest level, the build-time configuration sets none of these options,
1740thereby assuming an interface of type (1). However, some operating system
1741configuration files (for example, those for the BSD operating systems and
1742Linux) assume type (4) by setting USE_DB as their default, and the
1743configuration files for Cygwin set USE_GDBM. Anything you set in
9b371988 1744&_Local/Makefile_&, however, overrides these system defaults.
168e428f
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1745
1746As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1747necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1748in one of these lines:
9b371988
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1749.code
1750DBMLIB = -ldb
1751DBMLIB = -ltdb
1752.endd
168e428f
PH
1753Settings like that will work if the DBM library is installed in the standard
1754place. Sometimes it is not, and the library's header file may also not be in
1755the default path. You may need to set INCLUDE to specify where the header
1756file is, and to specify the path to the library more fully in DBMLIB, as in
1757this example:
9b371988
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1758.code
1759INCLUDE=-I/usr/local/include/db-4.1
1760DBMLIB=/usr/local/lib/db-4.1/libdb.a
1761.endd
168e428f 1762There is further detailed discussion about the various DBM libraries in the
9b371988 1763file &_doc/dbm.discuss.txt_& in the Exim distribution.
168e428f
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1764
1765
1766
f89d2485 1767.section "Pre-building configuration" "SECID25"
9b371988
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1768.cindex "building Exim" "pre-building configuration"
1769.cindex "configuration for building Exim"
1770.cindex "&_Local/Makefile_&"
1771.cindex "&_src/EDITME_&"
168e428f
PH
1772Before building Exim, a local configuration file that specifies options
1773independent of any operating system has to be created with the name
9b371988
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1774&_Local/Makefile_&. A template for this file is supplied as the file
1775&_src/EDITME_&, and it contains full descriptions of all the option settings
168e428f
PH
1776therein. These descriptions are therefore not repeated here. If you are
1777building Exim for the first time, the simplest thing to do is to copy
9b371988 1778&_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
168e428f
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1779
1780There are three settings that you must supply, because Exim will not build
1781without them. They are the location of the run time configuration file
1782(CONFIGURE_FILE), the directory in which Exim binaries will be installed
1783(BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1784maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1785a colon-separated list of file names; Exim uses the first of them that exists.
1786
1787There are a few other parameters that can be specified either at build time or
1788at run time, to enable the same binary to be used on a number of different
1789machines. However, if the locations of Exim's spool directory and log file
1790directory (if not within the spool directory) are fixed, it is recommended that
9b371988 1791you specify them in &_Local/Makefile_& instead of at run time, so that errors
168e428f
PH
1792detected early in Exim's execution (such as a malformed configuration file) can
1793be logged.
1794
9b371988 1795.cindex "content scanning" "specifying at build time"
068aaea8 1796Exim's interfaces for calling virus and spam scanning software directly from
168e428f
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1797access control lists are not compiled by default. If you want to include these
1798facilities, you need to set
9b371988
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1799.code
1800WITH_CONTENT_SCAN=yes
1801.endd
1802in your &_Local/Makefile_&. For details of the facilities themselves, see
1803chapter &<<CHAPexiscan>>&.
168e428f
PH
1804
1805
9b371988 1806.cindex "&_Local/eximon.conf_&"
3cb1b51e 1807.cindex "&_exim_monitor/EDITME_&"
168e428f 1808If you are going to build the Exim monitor, a similar configuration process is
9b371988
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1809required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1810your installation and saved under the name &_Local/eximon.conf_&. If you are
1811happy with the default settings described in &_exim_monitor/EDITME_&,
1812&_Local/eximon.conf_& can be empty, but it must exist.
168e428f
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1813
1814This is all the configuration that is needed in straightforward cases for known
1815operating systems. However, the building process is set up so that it is easy
1816to override options that are set by default or by operating-system-specific
1817configuration files, for example to change the name of the C compiler, which
9b371988
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1818defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1819do this.
168e428f
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1820
1821
1822
f89d2485 1823.section "Support for iconv()" "SECID26"
9b371988
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1824.cindex "&[iconv()]& support"
1825.cindex "RFC 2047"
168e428f
PH
1826The contents of header lines in messages may be encoded according to the rules
1827described RFC 2047. This makes it possible to transmit characters that are not
1828in the ASCII character set, and to label them as being in a particular
9b371988 1829character set. When Exim is inspecting header lines by means of the &%$h_%&
168e428f
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1830mechanism, it decodes them, and translates them into a specified character set
1831(default ISO-8859-1). The translation is possible only if the operating system
9b371988
PH
1832supports the &[iconv()]& function.
1833
1834However, some of the operating systems that supply &[iconv()]& do not support
1835very many conversions. The GNU &%libiconv%& library (available from
1836&url(http://www.gnu.org/software/libiconv/)) can be installed on such
1837systems to remedy this deficiency, as well as on systems that do not supply
1838&[iconv()]& at all. After installing &%libiconv%&, you should add
1839.code
1840HAVE_ICONV=yes
1841.endd
1842to your &_Local/Makefile_& and rebuild Exim.
1843
1844
1845
1846.section "Including TLS/SSL encryption support" "SECTinctlsssl"
1847.cindex "TLS" "including support for TLS"
1848.cindex "encryption" "including support for"
1849.cindex "SUPPORT_TLS"
1850.cindex "OpenSSL" "building Exim with"
1851.cindex "GnuTLS" "building Exim with"
168e428f
PH
1852Exim can be built to support encrypted SMTP connections, using the STARTTLS
1853command as per RFC 2487. It can also support legacy clients that expect to
1854start a TLS session immediately on connection to a non-standard port (see the
9b371988 1855&%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
168e428f
PH
1856line option).
1857
1858If you want to build Exim with TLS support, you must first install either the
1859OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1860implementing SSL.
1861
1862If OpenSSL is installed, you should set
9b371988
PH
1863.code
1864SUPPORT_TLS=yes
1865TLS_LIBS=-lssl -lcrypto
1866.endd
1867in &_Local/Makefile_&. You may also need to specify the locations of the
168e428f 1868OpenSSL library and include files. For example:
9b371988
PH
1869.code
1870SUPPORT_TLS=yes
1871TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1872TLS_INCLUDE=-I/usr/local/openssl/include/
1873.endd
1874.cindex "USE_GNUTLS"
168e428f 1875If GnuTLS is installed, you should set
9b371988
PH
1876.code
1877SUPPORT_TLS=yes
1878USE_GNUTLS=yes
1879TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1880.endd
1881in &_Local/Makefile_&, and again you may need to specify the locations of the
168e428f 1882library and include files. For example:
9b371988
PH
1883.code
1884SUPPORT_TLS=yes
1885USE_GNUTLS=yes
1886TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1887TLS_INCLUDE=-I/usr/gnu/include
1888.endd
168e428f 1889You do not need to set TLS_INCLUDE if the relevant directory is already
9b371988
PH
1890specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1891given in chapter &<<CHAPTLS>>&.
168e428f
PH
1892
1893
1894
1895
f89d2485
PH
1896.section "Use of tcpwrappers" "SECID27"
1897.cindex "tcpwrappers, building Exim to support"
9b371988
PH
1898.cindex "USE_TCP_WRAPPERS"
1899Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1900SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
168e428f 1901alternative to Exim's own checking facilities for installations that are
9b371988
PH
1902already making use of &'tcpwrappers'& for other purposes. To do this, you
1903should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1904&_tcpd.h_& to be available at compile time, and also ensure that the library
1905&_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1906EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1907you might have
1908.code
1909USE_TCP_WRAPPERS=yes
1910CFLAGS=-O -I/usr/local/include
1911EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1912.endd
1913in &_Local/Makefile_&. The name to use in the &'tcpwrappers'& control files is
1914&"exim"&. For example, the line
1915.code
1916exim : LOCAL 192.168.1. .friendly.domain.example
1917.endd
1918in your &_/etc/hosts.allow_& file allows connections from the local host, from
1919the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&.
1920All other connections are denied. Consult the &'tcpwrappers'& documentation for
168e428f
PH
1921further details.
1922
1923
1924
f89d2485 1925.section "Including support for IPv6" "SECID28"
9b371988 1926.cindex "IPv6" "including support for"
168e428f 1927Exim contains code for use on systems that have IPv6 support. Setting
9b371988 1928&`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
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1929it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1930where the IPv6 support is not fully integrated into the normal include and
1931library files.
1932
1933Two different types of DNS record for handling IPv6 addresses have been
f89d2485 1934defined. AAAA records (analogous to A records for IPv4) are in use, and are
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1935currently seen as the mainstream. Another record type called A6 was proposed
1936as better than AAAA because it had more flexibility. However, it was felt to be
9b371988 1937over-complex, and its status was reduced to &"experimental"&. It is not known
168e428f 1938if anyone is actually using A6 records. Exim has support for A6 records, but
9b371988 1939this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
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1940support has not been tested for some time.
1941
1942
1943
f89d2485 1944.section "The building process" "SECID29"
9b371988
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1945.cindex "build directory"
1946Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
1947created, run &'make'& at the top level. It determines the architecture and
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1948operating system types, and creates a build directory if one does not exist.
1949For example, on a Sun system running Solaris 8, the directory
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1950&_build-SunOS5-5.8-sparc_& is created.
1951.cindex "symbolic link" "to source files"
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1952Symbolic links to relevant source files are installed in the build directory.
1953
9b371988 1954&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
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1955building process fails if it is set.
1956
9b371988 1957If this is the first time &'make'& has been run, it calls a script that builds
168e428f 1958a make file inside the build directory, using the configuration files from the
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1959&_Local_& directory. The new make file is then passed to another instance of
1960&'make'&. This does the real work, building a number of utility scripts, and
168e428f 1961then compiling and linking the binaries for the Exim monitor (if configured), a
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1962number of utility programs, and finally Exim itself. The command &`make
1963makefile`& can be used to force a rebuild of the make file in the build
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1964directory, should this ever be necessary.
1965
1966If you have problems building Exim, check for any comments there may be in the
9b371988 1967&_README_& file concerning your operating system, and also take a look at the
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1968FAQ, where some common problems are covered.
1969
1970
1971
f89d2485 1972.section 'Output from &"make"&' "SECID283"
9b371988 1973The output produced by the &'make'& process for compile lines is often very
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1974unreadable, because these lines can be very long. For this reason, the normal
1975output is suppressed by default, and instead output similar to that which
1976appears when compiling the 2.6 Linux kernel is generated: just a short line for
1977each module that is being compiled or linked. However, it is still possible to
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1978get the full output, by calling &'make'& like this:
1979.code
1980FULLECHO='' make -e
1981.endd
1982The value of FULLECHO defaults to &"@"&, the flag character that suppresses
1983command reflection in &'make'&. When you ask for the full output, it is
3cb1b51e 1984given in addition to the short output.
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1985
1986
1987
9b371988 1988.section "Overriding build-time options for Exim" "SECToverride"
f89d2485 1989.cindex "build-time options, overriding"
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1990The main make file that is created at the beginning of the building process
1991consists of the concatenation of a number of files which set configuration
9b371988 1992values, followed by a fixed set of &'make'& instructions. If a value is set
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1993more than once, the last setting overrides any previous ones. This provides a
1994convenient way of overriding defaults. The files that are concatenated are, in
1995order:
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1996.display
1997&_OS/Makefile-Default_&
1998&_OS/Makefile-_&<&'ostype'&>
1999&_Local/Makefile_&
2000&_Local/Makefile-_&<&'ostype'&>
2001&_Local/Makefile-_&<&'archtype'&>
2002&_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
2003&_OS/Makefile-Base_&
2004.endd
2005.cindex "&_Local/Makefile_&"
2006.cindex "building Exim" "operating system type"
2007.cindex "building Exim" "architecture type"
2008where <&'ostype'&> is the operating system type and <&'archtype'&> is the
2009architecture type. &_Local/Makefile_& is required to exist, and the building
2010process fails if it is absent. The other three &_Local_& files are optional,
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2011and are often not needed.
2012
9b371988
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2013The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
2014called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
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2015the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
2016values are used, thereby providing a means of forcing particular settings.
9b371988 2017Otherwise, the scripts try to get values from the &%uname%& command. If this
168e428f 2018fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
9b371988 2019of &'ad hoc'& transformations are then applied, to produce the standard names
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2020that Exim expects. You can run these scripts directly from the shell in order
2021to find out what values are being used on your system.
2022
2023
9b371988 2024&_OS/Makefile-Default_& contains comments about the variables that are set
168e428f
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2025therein. Some (but not all) are mentioned below. If there is something that
2026needs changing, review the contents of this file and the contents of the make
9b371988 2027file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
168e428f
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2028default values are.
2029
2030
9b371988
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2031.cindex "building Exim" "overriding default settings"
2032If you need to change any of the values that are set in &_OS/Makefile-Default_&
2033or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
168e428f 2034need to change the original files. Instead, you should make the changes by
9b371988
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2035putting the new values in an appropriate &_Local_& file. For example,
2036.cindex "Tru64-Unix build-time settings"
168e428f
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2037when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2038formerly DEC-OSF1) operating system, it is necessary to specify that the C
9b371988
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2039compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2040called with the option &%-std1%&, to make it recognize some of the features of
168e428f 2041Standard C that Exim uses. (Most other compilers recognize Standard C by
9b371988 2042default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
168e428f 2043containing the lines
9b371988
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2044.code
2045CC=cc
2046CFLAGS=-std1
2047.endd
168e428f 2048If you are compiling for just one operating system, it may be easier to put
9b371988 2049these lines directly into &_Local/Makefile_&.
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2050
2051Keeping all your local configuration settings separate from the distributed
2052files makes it easy to transfer them to new versions of Exim simply by copying
9b371988 2053the contents of the &_Local_& directory.
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2054
2055
9b371988
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2056.cindex "NIS lookup type" "including support for"
2057.cindex "NIS+ lookup type" "including support for"
2058.cindex "LDAP" "including support for"
2059.cindex "lookup" "inclusion in binary"
168e428f
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2060Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2061lookup, but not all systems have these components installed, so the default is
2062not to include the relevant code in the binary. All the different kinds of file
2063and database lookup that Exim supports are implemented as separate code modules
2064which are included only if the relevant compile-time options are set. In the
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2065case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2066.code
2067LOOKUP_LDAP=yes
2068LOOKUP_NIS=yes
2069LOOKUP_NISPLUS=yes
2070.endd
168e428f 2071and similar settings apply to the other lookup types. They are all listed in
9b371988 2072&_src/EDITME_&. In many cases the relevant include files and interface
168e428f 2073libraries need to be installed before compiling Exim.
9b371988 2074.cindex "cdb" "including support for"
068aaea8
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2075However, there are some optional lookup types (such as cdb) for which
2076the code is entirely contained within Exim, and no external include
168e428f
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2077files or libraries are required. When a lookup type is not included in the
2078binary, attempts to configure Exim to use it cause run time configuration
2079errors.
2080
9b371988 2081.cindex "Perl" "including support for"
168e428f
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2082Exim can be linked with an embedded Perl interpreter, allowing Perl
2083subroutines to be called during string expansion. To enable this facility,
9b371988
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2084.code
2085EXIM_PERL=perl.o
2086.endd
2087must be defined in &_Local/Makefile_&. Details of this facility are given in
2088chapter &<<CHAPperl>>&.
168e428f 2089
f89d2485 2090.cindex "X11 libraries, location of"
168e428f 2091The location of the X11 libraries is something that varies a lot between
068aaea8 2092operating systems, and there may be different versions of X11 to cope
168e428f
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2093with. Exim itself makes no use of X11, but if you are compiling the Exim
2094monitor, the X11 libraries must be available.
9b371988
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2095The following three variables are set in &_OS/Makefile-Default_&:
2096.code
2097X11=/usr/X11R6
2098XINCLUDE=-I$(X11)/include
2099XLFLAGS=-L$(X11)/lib
2100.endd
168e428f 2101These are overridden in some of the operating-system configuration files. For
9b371988
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2102example, in &_OS/Makefile-SunOS5_& there is
2103.code
2104X11=/usr/openwin
2105XINCLUDE=-I$(X11)/include
2106XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2107.endd
168e428f
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2108If you need to override the default setting for your operating system, place a
2109definition of all three of these variables into your
9b371988 2110&_Local/Makefile-<ostype>_& file.
168e428f 2111
9b371988 2112.cindex "EXTRALIBS"
168e428f
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2113If you need to add any extra libraries to the link steps, these can be put in a
2114variable called EXTRALIBS, which appears in all the link commands, but by
2115default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2116command for linking the main Exim binary, and not for any associated utilities.
2117
9b371988 2118.cindex "DBM libraries" "configuration for building"
168e428f 2119There is also DBMLIB, which appears in the link commands for binaries that
9b371988 2120use DBM functions (see also section &<<SECTdb>>&). Finally, there is
168e428f
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2121EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2122binary, and which can be used, for example, to include additional X11
2123libraries.
2124
9b371988 2125.cindex "configuration file" "editing"
168e428f
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2126The make file copes with rebuilding Exim correctly if any of the configuration
2127files are edited. However, if an optional configuration file is deleted, it is
9b371988
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2128necessary to touch the associated non-optional file (that is,
2129&_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
168e428f
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2130
2131
f89d2485 2132.section "OS-specific header files" "SECID30"
9b371988
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2133.cindex "&_os.h_&"
2134.cindex "building Exim" "OS-specific C header files"
2135The &_OS_& directory contains a number of files with names of the form
2136&_os.h-<ostype>_&. These are system-specific C header files that should not
168e428f 2137normally need to be changed. There is a list of macro settings that are
9b371988 2138recognized in the file &_OS/os.configuring_&, which should be consulted if you
168e428f
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2139are porting Exim to a new operating system.
2140
2141
2142
f89d2485
PH
2143.section "Overriding build-time options for the monitor" "SECID31"
2144.cindex "building Eximon"
168e428f
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2145A similar process is used for overriding things when building the Exim monitor,
2146where the files that are involved are
9b371988
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2147.display
2148&_OS/eximon.conf-Default_&
2149&_OS/eximon.conf-_&<&'ostype'&>
2150&_Local/eximon.conf_&
2151&_Local/eximon.conf-_&<&'ostype'&>
2152&_Local/eximon.conf-_&<&'archtype'&>
2153&_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2154.endd
2155.cindex "&_Local/eximon.conf_&"
168e428f 2156As with Exim itself, the final three files need not exist, and in this case the
9b371988
PH
2157&_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2158&_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
168e428f
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2159variables of the same name, preceded by EXIMON_. For example, setting
2160EXIMON_LOG_DEPTH in the environment overrides the value of
2161LOG_DEPTH at run time.
4f578862 2162.ecindex IIDbuex
168e428f
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2163
2164
f89d2485 2165.section "Installing Exim binaries and scripts" "SECID32"
9b371988
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2166.cindex "installing Exim"
2167.cindex "BIN_DIRECTORY"
2168The command &`make install`& runs the &(exim_install)& script with no
2169arguments. The script copies binaries and utility scripts into the directory
2170whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2171.cindex "setuid" "installing Exim with"
068aaea8
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2172The install script copies files only if they are newer than the files they are
2173going to replace. The Exim binary is required to be owned by root and have the
9b371988
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2174&'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2175install`& as root so that it can set up the Exim binary in this way. However, in
068aaea8
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2176some special situations (for example, if a host is doing no local deliveries)
2177it may be possible to run Exim without making the binary setuid root (see
9b371988 2178chapter &<<CHAPsecurity>>& for details).
168e428f 2179
9b371988 2180.cindex "CONFIGURE_FILE"
168e428f 2181Exim's run time configuration file is named by the CONFIGURE_FILE setting
9b371988
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2182in &_Local/Makefile_&. If this names a single file, and the file does not
2183exist, the default configuration file &_src/configure.default_& is copied there
168e428f
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2184by the installation script. If a run time configuration file already exists, it
2185is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2186alternative files, no default is installed.
2187
9b371988
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2188.cindex "system aliases file"
2189.cindex "&_/etc/aliases_&"
168e428f
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2190One change is made to the default configuration file when it is installed: the
2191default configuration contains a router that references a system aliases file.
2192The path to this file is set to the value specified by
9b371988 2193SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
168e428f
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2194If the system aliases file does not exist, the installation script creates it,
2195and outputs a comment to the user.
2196
2197The created file contains no aliases, but it does contain comments about the
2198aliases a site should normally have. Mail aliases have traditionally been
9b371988
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2199kept in &_/etc/aliases_&. However, some operating systems are now using
2200&_/etc/mail/aliases_&. You should check if yours is one of these, and change
168e428f
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2201Exim's configuration if necessary.
2202
2203The default configuration uses the local host's name as the only local domain,
9b371988
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2204and is set up to do local deliveries into the shared directory &_/var/mail_&,
2205running as the local user. System aliases and &_.forward_& files in users' home
168e428f
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2206directories are supported, but no NIS or NIS+ support is configured. Domains
2207other than the name of the local host are routed using the DNS, with delivery
2208over SMTP.
2209
168e428f
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2210It is possible to install Exim for special purposes (such as building a binary
2211distribution) in a private part of the file system. You can do this by a
2212command such as
9b371988
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2213.code
2214make DESTDIR=/some/directory/ install
2215.endd
168e428f
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2216This has the effect of pre-pending the specified directory to all the file
2217paths, except the name of the system aliases file that appears in the default
9b371988 2218configuration. (If a default alias file is created, its name &'is'& modified.)
168e428f
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2219For backwards compatibility, ROOT is used if DESTDIR is not set,
2220but this usage is deprecated.
2221
9b371988
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2222.cindex "installing Exim" "what is not installed"
2223Running &'make install'& does not copy the Exim 4 conversion script
40df1be3
TF
2224&'convert4r4'&. You will probably run this only once if you are
2225upgrading from Exim 3. None of the documentation files in the &_doc_&
168e428f 2226directory are copied, except for the info files when you have set
9b371988 2227INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
168e428f 2228
9b371988 2229For the utility programs, old versions are renamed by adding the suffix &_.O_&
168e428f
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2230to their names. The Exim binary itself, however, is handled differently. It is
2231installed under a name that includes the version number and the compile number,
9b371988
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2232for example &_exim-&version;-1_&. The script then arranges for a symbolic link
2233called &_exim_& to point to the binary. If you are updating a previous version
2234of Exim, the script takes care to ensure that the name &_exim_& is never absent
168e428f
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2235from the directory (as seen by other processes).
2236
9b371988
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2237.cindex "installing Exim" "testing the script"
2238If you want to see what the &'make install'& will do before running it for
2239real, you can pass the &%-n%& option to the installation script by this
2240command:
2241.code
2242make INSTALL_ARG=-n install
2243.endd
168e428f
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2244The contents of the variable INSTALL_ARG are passed to the installation
2245script. You do not need to be root to run this test. Alternatively, you can run
2246the installation script directly, but this must be from within the build
2247directory. For example, from the top-level Exim directory you could use this
2248command:
9b371988
PH
2249.code
2250(cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2251.endd
2252.cindex "installing Exim" "install script options"
168e428f
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2253There are two other options that can be supplied to the installation script.
2254
9b371988
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2255.ilist
2256&%-no_chown%& bypasses the call to change the owner of the installed binary
168e428f 2257to root, and the call to make it a setuid binary.
9b371988
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2258.next
2259&%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
168e428f 2260installed binary.
9b371988 2261.endlist
168e428f
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2262
2263INSTALL_ARG can be used to pass these options to the script. For example:
9b371988
PH
2264.code
2265make INSTALL_ARG=-no_symlink install
2266.endd
168e428f
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2267The installation script can also be given arguments specifying which files are
2268to be copied. For example, to install just the Exim binary, and nothing else,
2269without creating the symbolic link, you could use:
9b371988
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2270.code
2271make INSTALL_ARG='-no_symlink exim' install
2272.endd
168e428f
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2273
2274
2275
9b371988
PH
2276.section "Installing info documentation" "SECTinsinfdoc"
2277.cindex "installing Exim" "&'info'& documentation"
2278Not all systems use the GNU &'info'& system for documentation, and for this
168e428f
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2279reason, the Texinfo source of Exim's documentation is not included in the main
2280distribution. Instead it is available separately from the ftp site (see section
9b371988 2281&<<SECTavail>>&).
168e428f 2282
9b371988
PH
2283If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2284source of the documentation is found in the source tree, running &`make
2285install`& automatically builds the info files and installs them.
168e428f
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2286
2287
2288
f89d2485 2289.section "Setting up the spool directory" "SECID33"
9b371988 2290.cindex "spool directory" "creating"
168e428f
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2291When it starts up, Exim tries to create its spool directory if it does not
2292exist. The Exim uid and gid are used for the owner and group of the spool
2293directory. Sub-directories are automatically created in the spool directory as
2294necessary.
2295
2296
2297
2298
f89d2485 2299.section "Testing" "SECID34"
9b371988 2300.cindex "testing" "installation"
168e428f
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2301Having installed Exim, you can check that the run time configuration file is
2302syntactically valid by running the following command, which assumes that the
2303Exim binary directory is within your PATH environment variable:
9b371988
PH
2304.code
2305exim -bV
2306.endd
168e428f
PH
2307If there are any errors in the configuration file, Exim outputs error messages.
2308Otherwise it outputs the version number and build date,
2309the DBM library that is being used, and information about which drivers and
2310other optional code modules are included in the binary.
2311Some simple routing tests can be done by using the address testing option. For
2312example,
9b371988
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2313.display
2314&`exim -bt`& <&'local username'&>
2315.endd
168e428f 2316should verify that it recognizes a local mailbox, and
9b371988
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2317.display
2318&`exim -bt`& <&'remote address'&>
2319.endd
168e428f
PH
2320a remote one. Then try getting it to deliver mail, both locally and remotely.
2321This can be done by passing messages directly to Exim, without going through a
2322user agent. For example:
9b371988 2323.code
068aaea8
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2324exim -v postmaster@your.domain.example
2325From: user@your.domain.example
2326To: postmaster@your.domain.example
2327Subject: Testing Exim
168e428f 2328
068aaea8
PH
2329This is a test message.
2330^D
9b371988
PH
2331.endd
2332The &%-v%& option causes Exim to output some verification of what it is doing.
168e428f 2333In this case you should see copies of three log lines, one for the message's
9b371988 2334arrival, one for its delivery, and one containing &"Completed"&.
168e428f 2335
9b371988
PH
2336.cindex "delivery" "problems with"
2337If you encounter problems, look at Exim's log files (&'mainlog'& and
2338&'paniclog'&) to see if there is any relevant information there. Another source
168e428f 2339of information is running Exim with debugging turned on, by specifying the
9b371988 2340&%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
168e428f 2341with debugging turned on by a command of the form
9b371988
PH
2342.display
2343&`exim -d -M`& <&'exim-message-id'&>
2344.endd
2345You must be root or an &"admin user"& in order to do this. The &%-d%& option
168e428f 2346produces rather a lot of output, but you can cut this down to specific areas.
9b371988
PH
2347For example, if you use &%-d-all+route%& only the debugging information
2348relevant to routing is included. (See the &%-d%& option in chapter
2349&<<CHAPcommandline>>& for more details.)
168e428f 2350
9b371988
PH
2351.cindex '&"sticky"& bit'
2352.cindex "lock files"
168e428f
PH
2353One specific problem that has shown up on some sites is the inability to do
2354local deliveries into a shared mailbox directory, because it does not have the
9b371988 2355&"sticky bit"& set on it. By default, Exim tries to create a lock file before
168e428f 2356writing to a mailbox file, and if it cannot create the lock file, the delivery
9b371988 2357is deferred. You can get round this either by setting the &"sticky bit"& on the
168e428f
PH
2358directory, or by setting a specific group for local deliveries and allowing
2359that group to create files in the directory (see the comments above the
9b371988 2360&(local_delivery)& transport in the default configuration file). Another
168e428f 2361approach is to configure Exim not to use lock files, but just to rely on
9b371988
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2362&[fcntl()]& locking instead. However, you should do this only if all user
2363agents also use &[fcntl()]& locking. For further discussion of locking issues,
2364see chapter &<<CHAPappendfile>>&.
168e428f
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2365
2366One thing that cannot be tested on a system that is already running an MTA is
2367the receipt of incoming SMTP mail on the standard SMTP port. However, the
9b371988
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2368&%-oX%& option can be used to run an Exim daemon that listens on some other
2369port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2370&'exim_checkaccess'& utility can be used to check out policy controls on
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2371incoming SMTP mail.
2372
2373Testing a new version on a system that is already running Exim can most easily
2374be done by building a binary with a different CONFIGURE_FILE setting. From
2375within the run time configuration, all other file and directory names
2376that Exim uses can be altered, in order to keep it entirely clear of the
2377production version.
2378
2379
f89d2485 2380.section "Replacing another MTA with Exim" "SECID35"
9b371988 2381.cindex "replacing another MTA"
168e428f
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2382Building and installing Exim for the first time does not of itself put it in
2383general use. The name by which the system's MTA is called by mail user agents
9b371988
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2384is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2385operating system), and it is necessary to make this name point to the &'exim'&
168e428f 2386binary in order to get the user agents to pass messages to Exim. This is
9b371988
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2387normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2388or &_/usr/lib/sendmail_&
2389.cindex "symbolic link" "to &'exim'& binary"
2390a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
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2391privilege and executable status from the old MTA. It is then necessary to stop
2392and restart the mailer daemon, if one is running.
2393
f89d2485 2394.cindex "FreeBSD, MTA indirection"
9b371988 2395.cindex "&_/etc/mail/mailer.conf_&"
168e428f
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2396Some operating systems have introduced alternative ways of switching MTAs. For
2397example, if you are running FreeBSD, you need to edit the file
9b371988 2398&_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
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2399described. A typical example of the contents of this file for running Exim is
2400as follows:
9b371988
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2401.code
2402sendmail /usr/exim/bin/exim
2403send-mail /usr/exim/bin/exim
2404mailq /usr/exim/bin/exim -bp
2405newaliases /usr/bin/true
2406.endd
2407Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2408your Exim installation is &"live"&. Check it by sending a message from your
168e428f
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2409favourite user agent.
2410
2411You should consider what to tell your users about the change of MTA. Exim may
2412have different capabilities to what was previously running, and there are
2413various operational differences such as the text of messages produced by
2414command line options and in bounce messages. If you allow your users to make
2415use of Exim's filtering capabilities, you should make the document entitled
9b371988 2416&'Exim's interface to mail filtering'& available to them.
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2417
2418
2419
f89d2485 2420.section "Upgrading Exim" "SECID36"
9b371988 2421.cindex "upgrading Exim"
168e428f
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2422If you are already running Exim on your host, building and installing a new
2423version automatically makes it available to MUAs, or any other programs that
2424call the MTA directly. However, if you are running an Exim daemon, you do need
9b371988
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2425to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2426new binary. You do not need to stop processing mail in order to install a new
068aaea8
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2427version of Exim. The install script does not modify an existing runtime
2428configuration file.
2429
168e428f
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2430
2431
2432
f89d2485 2433.section "Stopping the Exim daemon on Solaris" "SECID37"
9b371988 2434.cindex "Solaris" "stopping Exim on"
168e428f 2435The standard command for stopping the mailer daemon on Solaris is
9b371988
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2436.code
2437/etc/init.d/sendmail stop
2438.endd
2439If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2440fails to stop Exim because it uses the command &'ps -e'& and greps the output
2441for the text &"sendmail"&; this is not present because the actual program name
2442(that is, &"exim"&) is given by the &'ps'& command with these options. A
2443solution is to replace the line that finds the process id with something like
2444.code
2445pid=`cat /var/spool/exim/exim-daemon.pid`
2446.endd
168e428f
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2447to obtain the daemon's pid directly from the file that Exim saves it in.
2448
9b371988 2449Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
168e428f
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2450still be received from local processes, and if automatic delivery is configured
2451(the normal case), deliveries will still occur.
2452
2453
2454
2455
9b371988
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2456. ////////////////////////////////////////////////////////////////////////////
2457. ////////////////////////////////////////////////////////////////////////////
168e428f 2458
9b371988 2459.chapter "The Exim command line" "CHAPcommandline"
4f578862
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2460.scindex IIDclo1 "command line" "options"
2461.scindex IIDclo2 "options" "command line"
168e428f
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2462Exim's command line takes the standard Unix form of a sequence of options,
2463each starting with a hyphen character, followed by a number of arguments. The
2464options are compatible with the main options of Sendmail, and there are also
2465some additional options, some of which are compatible with Smail 3. Certain
2466combinations of options do not make sense, and provoke an error if used.
2467The form of the arguments depends on which options are set.
2468
2469
f89d2485 2470.section "Setting options by program name" "SECID38"
9b371988
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2471.cindex "&'mailq'&"
2472If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
168e428f 2473were present before any other options.
9b371988 2474The &%-bp%& option requests a listing of the contents of the mail queue on the
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2475standard output.
2476This feature is for compatibility with some systems that contain a command of
2477that name in one of the standard libraries, symbolically linked to
9b371988
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2478&_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2479
2480.cindex "&'rsmtp'&"
2481If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2482were present before any other options, for compatibility with Smail. The
2483&%-bS%& option is used for reading in a number of messages in batched SMTP
2484format.
2485
2486.cindex "&'rmail'&"
2487If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2488&%-oee%& options were present before any other options, for compatibility with
2489Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2490
2491.cindex "&'runq'&"
2492.cindex "queue runner"
2493If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2494were present before any other options, for compatibility with Smail. The &%-q%&
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2495option causes a single queue runner process to be started.
2496
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2497.cindex "&'newaliases'&"
2498.cindex "alias file" "building"
2499.cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2500If Exim is called under the name &'newaliases'& it behaves as if the option
2501&%-bi%& were present before any other options, for compatibility with Sendmail.
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2502This option is used for rebuilding Sendmail's alias file. Exim does not have
2503the concept of a single alias file, but can be configured to run a given
9b371988 2504command if called with the &%-bi%& option.
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2505
2506
9b371988
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2507.section "Trusted and admin users" "SECTtrustedadmin"
2508Some Exim options are available only to &'trusted users'& and others are
2509available only to &'admin users'&. In the description below, the phrases &"Exim
2510user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2511EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2512&%exim_group%& options. These do not necessarily have to use the name &"exim"&.
168e428f 2513
9b371988 2514.ilist
f89d2485 2515.cindex "trusted users" "definition of"
9b371988 2516.cindex "user" "trusted definition of"
168e428f 2517The trusted users are root, the Exim user, any user listed in the
9b371988
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2518&%trusted_users%& configuration option, and any user whose current group or any
2519supplementary group is one of those listed in the &%trusted_groups%&
168e428f 2520configuration option. Note that the Exim group is not automatically trusted.
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2521
2522.cindex '&"From"& line'
2523.cindex "envelope sender"
2524Trusted users are always permitted to use the &%-f%& option or a leading
2525&"From&~"& line to specify the envelope sender of a message that is passed to
2526Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2527See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2528users to set envelope senders.
2529
2530.cindex "&'From:'& header line"
2531.cindex "&'Sender:'& header line"
2532For a trusted user, there is never any check on the contents of the &'From:'&
2533header line, and a &'Sender:'& line is never added. Furthermore, any existing
2534&'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2535
168e428f
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2536Trusted users may also specify a host name, host address, interface address,
2537protocol name, ident value, and authentication data when submitting a message
2538locally. Thus, they are able to insert messages into Exim's queue locally that
2539have the characteristics of messages received from a remote host. Untrusted
9b371988 2540users may in some circumstances use &%-f%&, but can never set the other values
168e428f 2541that are available to trusted users.
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2542.next
2543.cindex "user" "admin definition of"
2544.cindex "admin user" "definition of"
168e428f 2545The admin users are root, the Exim user, and any user that is a member of the
9b371988 2546Exim group or of any group listed in the &%admin_groups%& configuration option.
168e428f 2547The current group does not have to be one of these groups.
9b371988 2548
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2549Admin users are permitted to list the queue, and to carry out certain
2550operations on messages, for example, to force delivery failures. It is also
2551necessary to be an admin user in order to see the full information provided by
2552the Exim monitor, and full debugging output.
9b371988
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2553
2554By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2555Exim to attempt delivery of messages on its queue is restricted to admin users.
2556However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2557option false (that is, specifying &%no_prod_requires_admin%&).
2558
2559Similarly, the use of the &%-bp%& option to list all the messages in the queue
2560is restricted to admin users unless &%queue_list_requires_admin%& is set
168e428f 2561false.
9b371988 2562.endlist
168e428f
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2563
2564
9b371988 2565&*Warning*&: If you configure your system so that admin users are able to
168e428f
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2566edit Exim's configuration file, you are giving those users an easy way of
2567getting root. There is further discussion of this issue at the start of chapter
9b371988 2568&<<CHAPconf>>&.
168e428f
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2569
2570
2571
2572
f89d2485 2573.section "Command line options" "SECID39"
db9452a9
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2574Exim's command line options are described in alphabetical order below. If none
2575of the options that specifies a specific action (such as starting the daemon or
2576a queue runner, or testing an address, or receiving a message in a specific
2577format, or listing the queue) are present, and there is at least one argument
2578on the command line, &%-bm%& (accept a local message on the standard input,
2579with the arguments specifying the recipients) is assumed. Otherwise, Exim
2580outputs a brief message about itself and exits.
168e428f 2581
9b371988
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2582. ////////////////////////////////////////////////////////////////////////////
2583. Insert a stylized XML comment here, to identify the start of the command line
2584. options. This is for the benefit of the Perl script that automatically
2585. creates a man page for the options.
2586. ////////////////////////////////////////////////////////////////////////////
168e428f 2587
9b371988 2588.literal xml
168e428f 2589<!-- === Start of command line options === -->
9b371988 2590.literal off
168e428f
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2591
2592
9b371988
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2593.vlist
2594.vitem &%--%&
2595.oindex "--"
2596.cindex "options" "command line; terminating"
168e428f
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2597This is a pseudo-option whose only purpose is to terminate the options and
2598therefore to cause subsequent command line items to be treated as arguments
2599rather than options, even if they begin with hyphens.
2600
9b371988
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2601.vitem &%--help%&
2602.oindex "&%--help%&"
168e428f
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2603This option causes Exim to output a few sentences stating what it is.
2604The same output is generated if the Exim binary is called with no options and
2605no arguments.
2606
9b371988
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2607.vitem &%-B%&<&'type'&>
2608.oindex "&%-B%&"
2609.cindex "8-bit characters"
2610.cindex "Sendmail compatibility" "8-bit characters"
168e428f
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2611This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2612clean; it ignores this option.
2613
9b371988
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2614.vitem &%-bd%&
2615.oindex "&%-bd%&"
2616.cindex "daemon"
f89d2485 2617.cindex "SMTP" "listener"
9b371988 2618.cindex "queue runner"
168e428f 2619This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
9b371988
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2620the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2621that the daemon should also initiate periodic queue runs.
2622
2623The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2624(debugging) or &%-v%& (verifying) options are set, the daemon does not
168e428f
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2625disconnect from the controlling terminal. When running this way, it can be
2626stopped by pressing ctrl-C.
9b371988 2627
168e428f
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2628By default, Exim listens for incoming connections to the standard SMTP port on
2629all the host's running interfaces. However, it is possible to listen on other
2630ports, on multiple ports, and only on specific interfaces. Chapter
9b371988
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2631&<<CHAPinterfaces>>& contains a description of the options that control this.
2632
168e428f 2633When a listening daemon
9b371988
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2634.cindex "daemon" "process id (pid)"
2635.cindex "pid (process id)" "of daemon"
2636is started without the use of &%-oX%& (that is, without overriding the normal
2637configuration), it writes its process id to a file called &_exim-daemon.pid_&
2638in Exim's spool directory. This location can be overridden by setting
2639PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
168e428f 2640running as root.
9b371988
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2641
2642When &%-oX%& is used on the command line to start a listening daemon, the
2643process id is not written to the normal pid file path. However, &%-oP%& can be
168e428f 2644used to specify a path on the command line if a pid file is required.
9b371988 2645
168e428f 2646The SIGHUP signal
9b371988 2647.cindex "SIGHUP"
3cb1b51e
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2648.cindex "daemon" "restarting"
2649can be used to cause the daemon to re-execute itself. This should be done
2650whenever Exim's configuration file, or any file that is incorporated into it by
2651means of the &%.include%& facility, is changed, and also whenever a new version
2652of Exim is installed. It is not necessary to do this when other files that are
9b371988
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2653referenced from the configuration (for example, alias files) are changed,
2654because these are reread each time they are used.
2655
2656.vitem &%-bdf%&
2657.oindex "&%-bdf%&"
2658This option has the same effect as &%-bd%& except that it never disconnects
2659from the controlling terminal, even when no debugging is specified.
2660
2661.vitem &%-be%&
2662.oindex "&%-be%&"
2663.cindex "testing" "string expansion"
2664.cindex "expansion" "testing"
168e428f
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2665Run Exim in expansion testing mode. Exim discards its root privilege, to
2666prevent ordinary users from using this mode to read otherwise inaccessible
2667files. If no arguments are given, Exim runs interactively, prompting for lines
4f578862 2668of data. Otherwise, it processes each argument in turn.
9b371988
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2669
2670If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2671to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2672used without command line arguments. If successful, it uses the &[readline()]&
168e428f
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2673function, which provides extensive line-editing facilities, for reading the
2674test data. A line history is supported.
9b371988 2675
168e428f 2676Long expansion expressions can be split over several lines by using backslash
068aaea8 2677continuations. As in Exim's run time configuration, white space at the start of
168e428f
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2678continuation lines is ignored. Each argument or data line is passed through the
2679string expansion mechanism, and the result is output. Variable values from the
9b371988 2680configuration file (for example, &$qualify_domain$&) are available, but no
3cb1b51e 2681message-specific values (such as &$sender_domain$&) are set, because no message
f89d2485 2682is being processed (but see &%-bem%& and &%-Mset%&).
168e428f 2683
9b371988
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2684&*Note*&: If you use this mechanism to test lookups, and you change the data
2685files or databases you are using, you must exit and restart Exim before trying
2686the same lookup again. Otherwise, because each Exim process caches the results
2687of lookups, you will just get the same result as before.
9b371988 2688
3cb1b51e
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2689.vitem &%-bem%&&~<&'filename'&>
2690.oindex "&%-bem%&"
2691.cindex "testing" "string expansion"
2692.cindex "expansion" "testing"
2693This option operates like &%-be%& except that it must be followed by the name
2694of a file. For example:
2695.code
2696exim -bem /tmp/testmessage
2697.endd
2698The file is read as a message (as if receiving a locally-submitted non-SMTP
2699message) before any of the test expansions are done. Thus, message-specific
2700variables such as &$message_size$& and &$header_from:$& are available. However,
2701no &'Received:'& header is added to the message. If the &%-t%& option is set,
2702recipients are read from the headers in the normal way, and are shown in the
2703&$recipients$& variable. Note that recipients cannot be given on the command
2704line, because further arguments are taken as strings to expand (just like
2705&%-be%&).
3cb1b51e 2706
9b371988
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2707.vitem &%-bF%&&~<&'filename'&>
2708.oindex "&%-bF%&"
2709.cindex "system filter" "testing"
2710.cindex "testing" "system filter"
2711This option is the same as &%-bf%& except that it assumes that the filter being
168e428f
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2712tested is a system filter. The additional commands that are available only in
2713system filters are recognized.
2714
9b371988
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2715.vitem &%-bf%&&~<&'filename'&>
2716.oindex "&%-bf%&"
2717.cindex "filter" "testing"
2718.cindex "testing" "filter file"
2719.cindex "forward file" "testing"
2720.cindex "testing" "forward file"
2721.cindex "Sieve filter" "testing"
168e428f
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2722This option runs Exim in user filter testing mode; the file is the filter file
2723to be tested, and a test message must be supplied on the standard input. If
2724there are no message-dependent tests in the filter, an empty file can be
2725supplied.
168e428f 2726
9b371988
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2727If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2728can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2729filter and a user filter in the same run. For example:
2730.code
2731exim -bF /system/filter -bf /user/filter </test/message
2732.endd
168e428f
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2733This is helpful when the system filter adds header lines or sets filter
2734variables that are used by the user filter.
168e428f 2735
9b371988
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2736If the test filter file does not begin with one of the special lines
2737.code
2738# Exim filter
2739# Sieve filter
2740.endd
2741it is taken to be a normal &_.forward_& file, and is tested for validity under
2742that interpretation. See sections &<<SECTitenonfilred>>& to
2743&<<SECTspecitredli>>& for a description of the possible contents of non-filter
2744redirection lists.
2745
2746The result of an Exim command that uses &%-bf%&, provided no errors are
168e428f
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2747detected, is a list of the actions that Exim would try to take if presented
2748with the message for real. More details of filter testing are given in the
9b371988
PH
2749separate document entitled &'Exim's interfaces to mail filtering'&.
2750
168e428f 2751When testing a filter file,
9b371988
PH
2752.cindex "&""From""& line"
2753.cindex "envelope sender"
f89d2485 2754.oindex "&%-f%&" "for filter testing"
9b371988
PH
2755the envelope sender can be set by the &%-f%& option,
2756or by a &"From&~"& line at the start of the test message. Various parameters
2757that would normally be taken from the envelope recipient address of the message
2758can be set by means of additional command line options (see the next four
2759options).
2760
2761.vitem &%-bfd%&&~<&'domain'&>
2762.oindex "&%-bfd%&"
f89d2485 2763.vindex "&$qualify_domain$&"
168e428f 2764This sets the domain of the recipient address when a filter file is being
9b371988
PH
2765tested by means of the &%-bf%& option. The default is the value of
2766&$qualify_domain$&.
168e428f 2767
9b371988
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2768.vitem &%-bfl%&&~<&'local&~part'&>
2769.oindex "&%-bfl%&"
168e428f 2770This sets the local part of the recipient address when a filter file is being
9b371988 2771tested by means of the &%-bf%& option. The default is the username of the
168e428f
PH
2772process that calls Exim. A local part should be specified with any prefix or
2773suffix stripped, because that is how it appears to the filter when a message is
2774actually being delivered.
2775
9b371988
PH
2776.vitem &%-bfp%&&~<&'prefix'&>
2777.oindex "&%-bfp%&"
168e428f 2778This sets the prefix of the local part of the recipient address when a filter
9b371988 2779file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
PH
2780prefix.
2781
9b371988
PH
2782.vitem &%-bfs%&&~<&'suffix'&>
2783.oindex "&%-bfs%&"
168e428f 2784This sets the suffix of the local part of the recipient address when a filter
9b371988 2785file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
PH
2786suffix.
2787
9b371988
PH
2788.vitem &%-bh%&&~<&'IP&~address'&>
2789.oindex "&%-bh%&"
2790.cindex "testing" "incoming SMTP"
2791.cindex "SMTP" "testing incoming"
2792.cindex "testing" "relay control"
2793.cindex "relaying" "testing configuration"
2794.cindex "policy control" "testing"
2795.cindex "debugging" "&%-bh%& option"
168e428f
PH
2796This option runs a fake SMTP session as if from the given IP address, using the
2797standard input and output. The IP address may include a port number at the end,
2798after a full stop. For example:
9b371988
PH
2799.code
2800exim -bh 10.9.8.7.1234
2801exim -bh fe80::a00:20ff:fe86:a061.5678
2802.endd
168e428f 2803When an IPv6 address is given, it is converted into canonical form. In the case
9b371988
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2804of the second example above, the value of &$sender_host_address$& after
2805conversion to the canonical form is
2806&`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2807
168e428f 2808Comments as to what is going on are written to the standard error file. These
9b371988 2809include lines beginning with &"LOG"& for anything that would have been logged.
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2810This facility is provided for testing configuration options for incoming
2811messages, to make sure they implement the required policy. For example, you can
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2812test your relay controls using &%-bh%&.
2813
2814&*Warning 1*&:
2815.cindex "RFC 1413"
db9452a9
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2816You can test features of the configuration that rely on ident (RFC 1413)
2817information by using the &%-oMt%& option. However, Exim cannot actually perform
2818an ident callout when testing using &%-bh%& because there is no incoming SMTP
2819connection.
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2820
2821&*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2822are also skipped when testing using &%-bh%&. If you want these callouts to
2823occur, use &%-bhc%& instead.
2824
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2825Messages supplied during the testing session are discarded, and nothing is
2826written to any of the real log files. There may be pauses when DNS (and other)
9b371988 2827lookups are taking place, and of course these may time out. The &%-oMi%& option
db9452a9
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2828can be used to specify a specific IP interface and port if this is important,
2829and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2830session were authenticated.
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2831
2832The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
168e428f 2833output just states whether a given recipient address from a given host is
9b371988 2834acceptable or not. See section &<<SECTcheckaccess>>&.
168e428f 2835
3cb1b51e 2836Features such as authentication and encryption, where the client input is not
f89d2485
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2837plain text, cannot easily be tested with &%-bh%&. Instead, you should use a
2838specialized SMTP test program such as
3cb1b51e 2839&url(http://jetmore.org/john/code/#swaks,swaks).
3cb1b51e 2840
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2841.vitem &%-bhc%&&~<&'IP&~address'&>
2842.oindex "&%-bhc%&"
2843This option operates in the same way as &%-bh%&, except that address
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2844verification callouts are performed if required. This includes consulting and
2845updating the callout cache database.
2846
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2847.vitem &%-bi%&
2848.oindex "&%-bi%&"
2849.cindex "alias file" "building"
2850.cindex "building alias file"
2851.cindex "Sendmail compatibility" "&%-bi%& option"
2852Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
168e428f 2853Exim does not have the concept of a single alias file, and so it cannot mimic
9b371988 2854this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
168e428f
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2855tend to appear in various scripts such as NIS make files, so the option must be
2856recognized.
9b371988
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2857
2858If &%-bi%& is encountered, the command specified by the &%bi_command%&
168e428f 2859configuration option is run, under the uid and gid of the caller of Exim. If
9b371988
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2860the &%-oA%& option is used, its value is passed to the command as an argument.
2861The command set by &%bi_command%& may not contain arguments. The command can
2862use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2863if this is required. If the &%bi_command%& option is not set, calling Exim with
2864&%-bi%& is a no-op.
2865
2866.vitem &%-bm%&
2867.oindex "&%-bm%&"
2868.cindex "local message reception"
168e428f
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2869This option runs an Exim receiving process that accepts an incoming,
2870locally-generated message on the current input. The recipients are given as the
9b371988 2871command arguments (except when &%-t%& is also present &-- see below). Each
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2872argument can be a comma-separated list of RFC 2822 addresses. This is the
2873default option for selecting the overall action of an Exim call; it is assumed
2874if no other conflicting option is present.
9b371988 2875
168e428f 2876If any addresses in the message are unqualified (have no domain), they are
9b371988
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2877qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
2878options, as appropriate. The &%-bnq%& option (see below) provides a way of
168e428f 2879suppressing this for special cases.
9b371988 2880
168e428f 2881Policy checks on the contents of local messages can be enforced by means of
9b371988
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2882the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
2883
2884.cindex "return code" "for &%-bm%&"
2885The return code is zero if the message is successfully accepted. Otherwise, the
2886action is controlled by the &%-oe%&&'x'& option setting &-- see below.
2887
168e428f 2888The format
9b371988
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2889.cindex "message" "format"
2890.cindex "format" "message"
2891.cindex "&""From""& line"
2892.cindex "UUCP" "&""From""& line"
2893.cindex "Sendmail compatibility" "&""From""& line"
168e428f
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2894of the message must be as defined in RFC 2822, except that, for
2895compatibility with Sendmail and Smail, a line in one of the forms
9b371988
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2896.code
2897From sender Fri Jan 5 12:55 GMT 1997
2898From sender Fri, 5 Jan 97 12:55:01
2899.endd
168e428f
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2900(with the weekday optional, and possibly with additional text after the date)
2901is permitted to appear at the start of the message. There appears to be no
2902authoritative specification of the format of this line. Exim recognizes it by
9b371988 2903matching against the regular expression defined by the &%uucp_from_pattern%&
168e428f 2904option, which can be changed if necessary.
9b371988 2905
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2906.oindex "&%-f%&" "overriding &""From""& line"
2907The specified sender is treated as if it were given as the argument to the
9b371988 2908&%-f%& option, but if a &%-f%& option is also present, its argument is used in
168e428f
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2909preference to the address taken from the message. The caller of Exim must be a
2910trusted user for the sender of a message to be set in this way.
2911
9b371988
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2912.vitem &%-bnq%&
2913.oindex "&%-bnq%&"
f89d2485 2914.cindex "address qualification, suppressing"
168e428f
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2915By default, Exim automatically qualifies unqualified addresses (those
2916without domains) that appear in messages that are submitted locally (that
2917is, not over TCP/IP). This qualification applies both to addresses in
2918envelopes, and addresses in header lines. Sender addresses are qualified using
9b371988
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2919&%qualify_domain%&, and recipient addresses using &%qualify_recipient%& (which
2920defaults to the value of &%qualify_domain%&).
2921
2922Sometimes, qualification is not wanted. For example, if &%-bS%& (batch SMTP) is
168e428f
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2923being used to re-submit messages that originally came from remote hosts after
2924content scanning, you probably do not want to qualify unqualified addresses in
2925header lines. (Such lines will be present only if you have not enabled a header
2926syntax check in the appropriate ACL.)
9b371988
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2927
2928The &%-bnq%& option suppresses all qualification of unqualified addresses in
168e428f
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2929messages that originate on the local host. When this is used, unqualified
2930addresses in the envelope provoke errors (causing message rejection) and
2931unqualified addresses in header lines are left alone.
2932
2933
9b371988
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2934.vitem &%-bP%&
2935.oindex "&%-bP%&"
595028e4 2936.cindex "configuration options" "extracting"
9b371988 2937.cindex "options" "configuration &-- extracting"
168e428f
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2938If this option is given with no arguments, it causes the values of all Exim's
2939main configuration options to be written to the standard output. The values
2940of one or more specific options can be requested by giving their names as
2941arguments, for example:
9b371988
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2942.code
2943exim -bP qualify_domain hold_domains
2944.endd
595028e4
PH
2945.cindex "hiding configuration option values"
2946.cindex "configuration options" "hiding value of"
2947.cindex "options" "hiding value of"
9b371988 2948However, any option setting that is preceded by the word &"hide"& in the
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2949configuration file is not shown in full, except to an admin user. For other
2950users, the output is as in this example:
9b371988
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2951.code
2952mysql_servers = <value not displayable>
2953.endd
2954If &%configure_file%& is given as an argument, the name of the run time
168e428f
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2955configuration file is output.
2956If a list of configuration files was supplied, the value that is output here
2957is the name of the file that was actually used.
168e428f 2958
9b371988
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2959.cindex "daemon" "process id (pid)"
2960.cindex "pid (process id)" "of daemon"
2961If &%log_file_path%& or &%pid_file_path%& are given, the names of the
2962directories where log files and daemon pid files are written are output,
2963respectively. If these values are unset, log files are written in a
2964sub-directory of the spool directory called &%log%&, and the pid file is
2965written directly into the spool directory.
2966
2967If &%-bP%& is followed by a name preceded by &`+`&, for example,
2968.code
2969exim -bP +local_domains
2970.endd
168e428f
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2971it searches for a matching named list of any type (domain, host, address, or
2972local part) and outputs what it finds.
9b371988
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2973
2974.cindex "options" "router &-- extracting"
2975.cindex "options" "transport &-- extracting"
5d9c27ec 2976.cindex "options" "authenticator &-- extracting"
9b371988 2977If one of the words &%router%&, &%transport%&, or &%authenticator%& is given,
168e428f
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2978followed by the name of an appropriate driver instance, the option settings for
2979that driver are output. For example:
9b371988
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2980.code
2981exim -bP transport local_delivery
2982.endd
168e428f
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2983The generic driver options are output first, followed by the driver's private
2984options. A list of the names of drivers of a particular type can be obtained by
9b371988
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2985using one of the words &%router_list%&, &%transport_list%&, or
2986&%authenticator_list%&, and a complete list of all drivers with their option
2987settings can be obtained by using &%routers%&, &%transports%&, or
2988&%authenticators%&.
168e428f 2989
5d9c27ec
TK
2990.cindex "options" "macro &-- extracting"
2991If invoked by an admin user, then &%macro%&, &%macro_list%& and &%macros%&
2992are available, similarly to the drivers. Because macros are sometimes used
2993for storing passwords, this option is restricted.
2994The output format is one item per line.
168e428f 2995
9b371988
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2996.vitem &%-bp%&
2997.oindex "&%-bp%&"
2998.cindex "queue" "listing messages on"
2999.cindex "listing" "messages on the queue"
168e428f 3000This option requests a listing of the contents of the mail queue on the
9b371988 3001standard output. If the &%-bp%& option is followed by a list of message ids,
168e428f 3002just those messages are listed. By default, this option can be used only by an
9b371988 3003admin user. However, the &%queue_list_requires_admin%& option can be set false
168e428f 3004to allow any user to see the queue.
168e428f 3005
9b371988
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3006Each message on the queue is displayed as in the following example:
3007.code
300825m 2.9K 0t5C6f-0000c8-00 <alice@wonderland.fict.example>
3009 red.king@looking-glass.fict.example
3010 <other addresses>
3011.endd
3012.cindex "message" "size in queue listing"
3013.cindex "size" "of message"
3014The first line contains the length of time the message has been on the queue
168e428f
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3015(in this case 25 minutes), the size of the message (2.9K), the unique local
3016identifier for the message, and the message sender, as contained in the
3017envelope. For bounce messages, the sender address is empty, and appears as
9b371988 3018&"<>"&. If the message was submitted locally by an untrusted user who overrode
168e428f
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3019the default sender address, the user's login name is shown in parentheses
3020before the sender address.
9b371988
PH
3021
3022.cindex "frozen messages" "in queue listing"
3023If the message is frozen (attempts to deliver it are suspended) then the text
3024&"*** frozen ***"& is displayed at the end of this line.
3025
168e428f
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3026The recipients of the message (taken from the envelope, not the headers) are
3027displayed on subsequent lines. Those addresses to which the message has already
3028been delivered are marked with the letter D. If an original address gets
3029expanded into several addresses via an alias or forward file, the original is
3030displayed with a D only when deliveries for all of its child addresses are
3031complete.
3032
3033
9b371988
PH
3034.vitem &%-bpa%&
3035.oindex "&%-bpa%&"
3036This option operates like &%-bp%&, but in addition it shows delivered addresses
168e428f 3037that were generated from the original top level address(es) in each message by
9b371988
PH
3038alias or forwarding operations. These addresses are flagged with &"+D"& instead
3039of just &"D"&.
168e428f
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3040
3041
9b371988
PH
3042.vitem &%-bpc%&
3043.oindex "&%-bpc%&"
3044.cindex "queue" "count of messages on"
168e428f
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3045This option counts the number of messages on the queue, and writes the total
3046to the standard output. It is restricted to admin users, unless
9b371988 3047&%queue_list_requires_admin%& is set false.
168e428f
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3048
3049
9b371988
PH
3050.vitem &%-bpr%&
3051.oindex "&%-bpr%&"
3052This option operates like &%-bp%&, but the output is not sorted into
168e428f
PH
3053chronological order of message arrival. This can speed it up when there are
3054lots of messages on the queue, and is particularly useful if the output is
3055going to be post-processed in a way that doesn't need the sorting.
3056
9b371988
PH
3057.vitem &%-bpra%&