Correct comment.
[exim.git] / doc / doc-docbook / spec.xfpt
CommitLineData
f89d2485 1. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.16 2007/04/11 15:26:09 ph10 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.
8. /////////////////////////////////////////////////////////////////////////////
9
10.include stdflags
11.include stdmacs
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12
13. /////////////////////////////////////////////////////////////////////////////
33393583 14. This outputs the standard DocBook boilerplate.
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15. /////////////////////////////////////////////////////////////////////////////
16
33393583 17.docbook
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18
19. /////////////////////////////////////////////////////////////////////////////
20. These lines are processing instructions for the Simple DocBook Processor that
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21. Philip Hazel has developed as a less cumbersome way of making PostScript and
22. PDFs than using xmlto and fop. They will be ignored by all other XML
23. processors.
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24. /////////////////////////////////////////////////////////////////////////////
25
26.literal xml
27<?sdop
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28 foot_right_recto="&chaptertitle; (&chapternumber;)"
29 foot_right_verso="&chaptertitle; (&chapternumber;)"
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30 toc_chapter_blanks="yes,yes"
31 table_warn_soft_overflow="no"
32?>
33.literal off
9b371988 34
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35. /////////////////////////////////////////////////////////////////////////////
36. This generate the outermost <book> element that wraps then entire document.
37. /////////////////////////////////////////////////////////////////////////////
38
39.book
40
41. /////////////////////////////////////////////////////////////////////////////
42. These definitions set some parameters and save some typing. Remember that
43. the <bookinfo> element must also be updated for each new edition.
44. /////////////////////////////////////////////////////////////////////////////
45
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46.set previousversion "4.66"
47.set version "4.67"
48
33393583 49.set ACL "access control lists (ACLs)"
f89d2485 50.set I "&nbsp;&nbsp;&nbsp;&nbsp;"
33393583 51
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52
53. /////////////////////////////////////////////////////////////////////////////
54. Additional xfpt markup used by this document, over and above the default
55. provided in the xfpt library.
56. /////////////////////////////////////////////////////////////////////////////
57
58. --- Override the &$ flag to automatically insert a $ with the variable name
59
60.flag &$ $& "<varname>$" "</varname>"
61
62. --- Short flags for daggers in option headings. They will always be inside
63. --- an italic string, but we want the daggers to be roman.
64
65.flag &!! "</emphasis>&dagger;<emphasis>"
66.flag &!? "</emphasis>&Dagger;<emphasis>"
67
68. --- A macro for an Exim option definition heading, generating a one-line
69. --- table with four columns.
70
71.macro option
3cb1b51e 72.oindex "&%$1%&"
f89d2485 73.itable all 0 0 4 8* left 6* center 6* center 6* right
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74.row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&"
75.endtable
76.endmacro
77
78. --- A macro for the common 2-column tables. The width of the first column
79. --- is suitable for the many tables at the start of the main options chapter;
80. --- the small number of other 2-column tables override it.
81
db9452a9 82.macro table2 196pt 254pt
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83.itable none 0 0 2 $1 left $2 left
84.endmacro
85
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86. --- A macro that generates .row, but puts &I; at the start of the first
87. --- argument, thus indenting it. Assume a minimum of two arguments, and
88. --- allow up to four arguments, which is as many as we'll ever need.
89
90.macro irow
91.arg 4
92.row "&I;$1" "$2" "$3" "$4"
93.endarg
94.arg -4
95.arg 3
96.row "&I;$1" "$2" "$3"
97.endarg
98.arg -3
99.row "&I;$1" "$2"
100.endarg
101.endarg
102.endmacro
103
104. --- Macros for option, variable, and concept index entries. For a "range"
105. --- style of entry, use .scindex for the start and .ecindex for the end. The
106. --- first argument of .scindex and the only argument of .ecindex must be the
107. --- ID that ties them together.
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108
109.macro cindex
110&<indexterm role="concept">&
111&<primary>&$1&</primary>&
112.arg 2
113&<secondary>&$2&</secondary>&
114.endarg
115&</indexterm>&
116.endmacro
117
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118.macro scindex
119&<indexterm role="concept" id="$1" class="startofrange">&
120&<primary>&$2&</primary>&
121.arg 3
122&<secondary>&$3&</secondary>&
123.endarg
124&</indexterm>&
125.endmacro
126
127.macro ecindex
128&<indexterm role="concept" startref="$1" class="endofrange"/>&
129.endmacro
130
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131.macro oindex
132&<indexterm role="option">&
133&<primary>&$1&</primary>&
134.arg 2
135&<secondary>&$2&</secondary>&
136.endarg
137&</indexterm>&
138.endmacro
139
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140.macro vindex
141&<indexterm role="variable">&
142&<primary>&$1&</primary>&
143.arg 2
144&<secondary>&$2&</secondary>&
145.endarg
146&</indexterm>&
147.endmacro
148
9b371988 149.macro index
f89d2485 150.echo "** Don't use .index; use .cindex or .oindex or .vindex"
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151.endmacro
152. ////////////////////////////////////////////////////////////////////////////
153
154
155. ////////////////////////////////////////////////////////////////////////////
156. The <bookinfo> element is removed from the XML before processing for Ascii
157. output formats.
158. ////////////////////////////////////////////////////////////////////////////
159
160.literal xml
161<bookinfo>
162<title>Specification of the Exim Mail Transfer Agent</title>
163<titleabbrev>The Exim MTA</titleabbrev>
f89d2485 164<date>10 April 2007</date>
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165<author><firstname>Philip</firstname><surname>Hazel</surname></author>
166<authorinitials>PH</authorinitials>
167<affiliation><orgname>University of Cambridge Computing Service</orgname></affiliation>
168<address>New Museums Site, Pembroke Street, Cambridge CB2 3QH, England</address>
169<revhistory><revision>
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170 <revnumber>4.67</revnumber>
171 <date>10 April 2007</date>
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172 <authorinitials>PH</authorinitials>
173</revision></revhistory>
ad268134 174<copyright><year>2007</year><holder>University of Cambridge</holder></copyright>
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175</bookinfo>
176.literal off
177
178
179. /////////////////////////////////////////////////////////////////////////////
180. This chunk of literal XML implements index entries of the form "x, see y" and
181. "x, see also y". However, the DocBook DTD doesn't allow <indexterm> entries
182. at the top level, so we have to put the .chapter directive first.
183. /////////////////////////////////////////////////////////////////////////////
184
f89d2485 185.chapter "Introduction" "CHID1"
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186.literal xml
187
f89d2485 188<indexterm role="variable">
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189 <primary>$1, $2, etc.</primary>
190 <see><emphasis>numerical variables</emphasis></see>
191</indexterm>
192<indexterm role="concept">
193 <primary>address</primary>
194 <secondary>rewriting</secondary>
195 <see><emphasis>rewriting</emphasis></see>
196</indexterm>
197<indexterm role="concept">
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198 <primary>Bounce Address Tag Validation</primary>
199 <see><emphasis>BATV</emphasis></see>
200</indexterm>
201<indexterm role="concept">
202 <primary>Client SMTP Authorization</primary>
203 <see><emphasis>CSA</emphasis></see>
204</indexterm>
205<indexterm role="concept">
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206 <primary>CR character</primary>
207 <see><emphasis>carriage return</emphasis></see>
208</indexterm>
209<indexterm role="concept">
210 <primary>CRL</primary>
211 <see><emphasis>certificate revocation list</emphasis></see>
212</indexterm>
213<indexterm role="concept">
214 <primary>delivery</primary>
215 <secondary>failure report</secondary>
216 <see><emphasis>bounce message</emphasis></see>
217</indexterm>
218<indexterm role="concept">
219 <primary>dialup</primary>
220 <see><emphasis>intermittently connected hosts</emphasis></see>
221</indexterm>
222<indexterm role="concept">
223 <primary>exiscan</primary>
224 <see><emphasis>content scanning</emphasis></see>
225</indexterm>
226<indexterm role="concept">
227 <primary>failover</primary>
228 <see><emphasis>fallback</emphasis></see>
229</indexterm>
230<indexterm role="concept">
231 <primary>fallover</primary>
232 <see><emphasis>fallback</emphasis></see>
233</indexterm>
234<indexterm role="concept">
235 <primary>filter</primary>
236 <secondary>Sieve</secondary>
237 <see><emphasis>Sieve filter</emphasis></see>
238</indexterm>
239<indexterm role="concept">
240 <primary>ident</primary>
241 <see><emphasis>RFC 1413</emphasis></see>
242</indexterm>
243<indexterm role="concept">
244 <primary>LF character</primary>
245 <see><emphasis>linefeed</emphasis></see>
246</indexterm>
247<indexterm role="concept">
248 <primary>maximum</primary>
249 <see><emphasis>limit</emphasis></see>
250</indexterm>
251<indexterm role="concept">
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252 <primary>monitor</primary>
253 <see><emphasis>Exim monitor</emphasis></see>
254</indexterm>
255<indexterm role="concept">
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256 <primary>no_<emphasis>xxx</emphasis></primary>
257 <see>entry for xxx</see>
258</indexterm>
259<indexterm role="concept">
260 <primary>NUL</primary>
261 <see><emphasis>binary zero</emphasis></see>
262</indexterm>
263<indexterm role="concept">
264 <primary>passwd file</primary>
265 <see><emphasis>/etc/passwd</emphasis></see>
266</indexterm>
267<indexterm role="concept">
268 <primary>process id</primary>
269 <see><emphasis>pid</emphasis></see>
270</indexterm>
271<indexterm role="concept">
272 <primary>RBL</primary>
273 <see><emphasis>DNS list</emphasis></see>
274</indexterm>
275<indexterm role="concept">
276 <primary>redirection</primary>
277 <see><emphasis>address redirection</emphasis></see>
278</indexterm>
279<indexterm role="concept">
280 <primary>return path</primary>
281 <seealso><emphasis>envelope sender</emphasis></seealso>
282</indexterm>
283<indexterm role="concept">
284 <primary>scanning</primary>
285 <see><emphasis>content scanning</emphasis></see>
286</indexterm>
287<indexterm role="concept">
288 <primary>SSL</primary>
289 <see><emphasis>TLS</emphasis></see>
290</indexterm>
291<indexterm role="concept">
292 <primary>string</primary>
293 <secondary>expansion</secondary>
294 <see><emphasis>expansion</emphasis></see>
295</indexterm>
296<indexterm role="concept">
297 <primary>top bit</primary>
298 <see><emphasis>8-bit characters</emphasis></see>
299</indexterm>
300<indexterm role="concept">
301 <primary>variables</primary>
302 <see><emphasis>expansion, variables</emphasis></see>
303</indexterm>
304<indexterm role="concept">
305 <primary>zero, binary</primary>
306 <see><emphasis>binary zero</emphasis></see>
307</indexterm>
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308
309.literal off
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310
311
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312. /////////////////////////////////////////////////////////////////////////////
313. This is the real start of the first chapter. See the comment above as to why
314. we can't have the .chapter line here.
315. chapter "Introduction"
316. /////////////////////////////////////////////////////////////////////////////
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317
318Exim is a mail transfer agent (MTA) for hosts that are running Unix or
319Unix-like operating systems. It was designed on the assumption that it would be
320run on hosts that are permanently connected to the Internet. However, it can be
321used on intermittently connected hosts with suitable configuration adjustments.
322
323Configuration files currently exist for the following operating systems: AIX,
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324BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, Dragonfly, FreeBSD, GNU/Hurd,
325GNU/Linux, HI-OSF (Hitachi), HI-UX, HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD,
326OpenUNIX, QNX, SCO, SCO SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4,
327Tru64-Unix (formerly Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware.
328Some of these operating systems are no longer current and cannot easily be
329tested, so the configuration files may no longer work in practice.
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330
331There are also configuration files for compiling Exim in the Cygwin environment
332that can be installed on systems running Windows. However, this document does
333not contain any information about running Exim in the Cygwin environment.
334
335The terms and conditions for the use and distribution of Exim are contained in
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336the file &_NOTICE_&. Exim is distributed under the terms of the GNU General
337Public Licence, a copy of which may be found in the file &_LICENCE_&.
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338
339The use, supply or promotion of Exim for the purpose of sending bulk,
340unsolicited electronic mail is incompatible with the basic aims of the program,
341which revolve around the free provision of a service that enhances the quality
342of personal communications. The author of Exim regards indiscriminate
343mass-mailing as an antisocial, irresponsible abuse of the Internet.
344
345Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
346experience of running and working on the Smail 3 code, I could never have
347contemplated starting to write a new MTA. Many of the ideas and user interfaces
348were originally taken from Smail 3, though the actual code of Exim is entirely
349new, and has developed far beyond the initial concept.
350
351Many people, both in Cambridge and around the world, have contributed to the
352development and the testing of Exim, and to porting it to various operating
353systems. I am grateful to them all. The distribution now contains a file called
9b371988 354&_ACKNOWLEDGMENTS_&, in which I have started recording the names of
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355contributors.
356
357
f89d2485 358.section "Exim documentation" "SECID1"
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359.new
360.cindex "documentation"
361This edition of the Exim specification applies to version &version; of Exim.
362Substantive changes from the &previousversion; edition are marked in some
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363renditions of the document; this paragraph is so marked if the rendition is
364capable of showing a change indicator.
9b371988 365.wen
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366
367This document is very much a reference manual; it is not a tutorial. The reader
368is expected to have some familiarity with the SMTP mail transfer protocol and
369with general Unix system administration. Although there are some discussions
370and examples in places, the information is mostly organized in a way that makes
371it easy to look up, rather than in a natural order for sequential reading.
372Furthermore, the manual aims to cover every aspect of Exim in detail, including
373a number of rarely-used, special-purpose features that are unlikely to be of
374very wide interest.
375
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376.cindex "books about Exim"
377An &"easier"& discussion of Exim which provides more in-depth explanatory,
378introductory, and tutorial material can be found in a book entitled &'The Exim
379SMTP Mail Server'&, published by UIT Cambridge
380(&url(http://www.uit.co.uk/exim-book/)).
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381
382This book also contains a chapter that gives a general introduction to SMTP and
383Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
384with the latest release of Exim. (Note that the earlier book about Exim,
385published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
386
9b371988 387.cindex "Debian" "information sources"
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388If you are using a Debian distribution of Exim, you will find information about
389Debian-specific features in the file
f89d2485 390&_/usr/share/doc/exim4-base/README.Debian_&.
9b371988 391The command &(man update-exim.conf)& is another source of Debian-specific
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392information.
393
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394.cindex "&_doc/NewStuff_&"
395.cindex "&_doc/ChangeLog_&"
396.cindex "change log"
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397As the program develops, there may be features in newer versions that have not
398yet made it into this document, which is updated only when the most significant
399digit of the fractional part of the version number changes. Specifications of
400new features that are not yet in this manual are placed in the file
9b371988 401&_doc/NewStuff_& in the Exim distribution.
168e428f 402
9b371988 403Some features may be classified as &"experimental"&. These may change
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404incompatibly while they are developing, or even be withdrawn. For this reason,
405they are not documented in this manual. Information about experimental features
9b371988 406can be found in the file &_doc/experimental.txt_&.
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407
408All changes to the program (whether new features, bug fixes, or other kinds of
9b371988 409change) are noted briefly in the file called &_doc/ChangeLog_&.
168e428f 410
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411.cindex "&_doc/spec.txt_&"
412This specification itself is available as an ASCII file in &_doc/spec.txt_& so
413that it can easily be searched with a text editor. Other files in the &_doc_&
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414directory are:
415
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416.table2 100pt
417.row &_OptionLists.txt_& "list of all options in alphabetical order"
418.row &_dbm.discuss.txt_& "discussion about DBM libraries"
419.row &_exim.8_& "a man page of Exim's command line options"
420.row &_experimental.txt_& "documentation of experimental features"
421.row &_filter.txt_& "specification of the filter language"
422.row &_pcrepattern.txt_& "specification of PCRE regular expressions"
423.row &_pcretest.txt_& "specification of the PCRE testing program"
424.row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
425.row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
426.endtable
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427
428The main specification and the specification of the filtering language are also
429available in other formats (HTML, PostScript, PDF, and Texinfo). Section
9b371988 430&<<SECTavail>>& below tells you how to get hold of these.
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431
432
433
f89d2485 434.section "FTP and web sites" "SECID2"
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435.cindex "web site"
436.cindex "FTP site"
068aaea8 437The primary site for Exim source distributions is currently the University of
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438Cambridge's FTP site, whose contents are described in &'Where to find the Exim
439distribution'& below. In addition, there is a web site and an FTP site at
440&%exim.org%&. These are now also hosted at the University of Cambridge. The
441&%exim.org%& site was previously hosted for a number of years by Energis
442Squared, formerly Planet Online Ltd, whose support I gratefully acknowledge.
443
444.cindex "wiki"
445.cindex "FAQ"
f89d2485 446.new
168e428f 447As well as Exim distribution tar files, the Exim web site contains a number of
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448differently formatted versions of the documentation. A recent addition to the
449online information is the Exim wiki (&url(http://www.exim.org/eximwiki/)),
450which contains what used to be a separate FAQ, as well as various other
451examples, tips, and know-how that have been contributed by Exim users.
452
453.cindex Bugzilla
454An Exim Bugzilla exists at &url(http://www.exim.org/bugzilla/). You can use
455this to report bugs, and also to add items to the wish list. Please search
456first to check that you are not duplicating a previous entry.
457.wen
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458
459
460
f89d2485 461.section "Mailing lists" "SECID3"
9b371988 462.cindex "mailing lists" "for Exim users"
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463.new
464The following Exim mailing lists exist:
168e428f 465
9b371988 466.table2 140pt
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467.row &'exim-users@exim.org'& "General discussion list"
468.row &'exim-dev@exim.org'& "Discussion of bugs, enhancements, etc."
469.row &'exim-announce@exim.org'& "Moderated, low volume announcements list"
470.row &'exim-future@exim.org'& "Discussion of long-term development"
9b371988 471.endtable
f89d2485 472.wen
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473
474You can subscribe to these lists, change your existing subscriptions, and view
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475or search the archives via the mailing lists link on the Exim home page.
476.cindex "Debian" "mailing list for"
4f578862 477If you are using a Debian distribution of Exim, you may wish to subscribe to
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478the Debian-specific mailing list &'pkg-exim4-users@lists.alioth.debian.org'&
479via this web page:
480.display
481&url(http://lists.alioth.debian.org/mailman/listinfo/pkg-exim4-users)
482.endd
483Please ask Debian-specific questions on this list and not on the general Exim
484lists.
9b371988 485
f89d2485 486.section "Exim training" "SECID4"
9b371988 487.cindex "training courses"
068aaea8 488From time to time (approximately annually at the time of writing), training
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489courses are run by the author of Exim in Cambridge, UK. Details of any
490forthcoming courses can be found on the web site
491&url(http://www-tus.csx.cam.ac.uk/courses/exim/).
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492
493
f89d2485 494.section "Bug reports" "SECID5"
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495.cindex "bug reports"
496.cindex "reporting bugs"
497Reports of obvious bugs should be emailed to &'bugs@exim.org'&. However, if you
498are unsure whether some behaviour is a bug or not, the best thing to do is to
499post a message to the &'exim-dev'& mailing list and have it discussed.
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500
501
502
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503.section "Where to find the Exim distribution" "SECTavail"
504.cindex "FTP site"
505.cindex "distribution" "ftp site"
168e428f 506The master ftp site for the Exim distribution is
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507.display
508&*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim*&
509.endd
168e428f 510This is mirrored by
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511.display
512&*ftp://ftp.exim.org/pub/exim*&
513.endd
514The file references that follow are relative to the &_exim_& directories at
515these sites. There are now quite a number of independent mirror sites around
516the world. Those that I know about are listed in the file called &_Mirrors_&.
517
518Within the &_exim_& directory there are subdirectories called &_exim3_& (for
519previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
520distributions), and &_Testing_& for testing versions. In the &_exim4_&
168e428f 521subdirectory, the current release can always be found in files called
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522.display
523&_exim-n.nn.tar.gz_&
524&_exim-n.nn.tar.bz2_&
525.endd
526where &'n.nn'& is the highest such version number in the directory. The two
168e428f 527files contain identical data; the only difference is the type of compression.
9b371988 528The &_.bz2_& file is usually a lot smaller than the &_.gz_& file.
168e428f 529
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530.cindex "distribution" "signing details"
531.cindex "distribution" "public key"
532.cindex "public key for signed distribution"
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533The distributions are currently signed with Philip Hazel's GPG key. The
534corresponding public key is available from a number of keyservers, and there is
9b371988 535also a copy in the file &_Public-Key_&. The signatures for the tar bundles are
168e428f 536in:
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537.display
538&_exim-n.nn.tar.gz.sig_&
539&_exim-n.nn.tar.bz2.sig_&
540.endd
168e428f 541For each released version, the log of changes is made separately available in a
9b371988 542separate file in the directory &_ChangeLogs_& so that it is possible to
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543find out what has changed without having to download the entire distribution.
544
9b371988 545.cindex "documentation" "available formats"
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546The main distribution contains ASCII versions of this specification and other
547documentation; other formats of the documents are available in separate files
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548inside the &_exim4_& directory of the FTP site:
549.display
550&_exim-html-n.nn.tar.gz_&
551&_exim-pdf-n.nn.tar.gz_&
552&_exim-postscript-n.nn.tar.gz_&
553&_exim-texinfo-n.nn.tar.gz_&
554.endd
555These tar files contain only the &_doc_& directory, not the complete
556distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
168e428f 557
168e428f 558
f89d2485 559.section "Limitations" "SECID6"
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560.ilist
561.cindex "limitations of Exim"
562.cindex "bang paths" "not handled by Exim"
563Exim is designed for use as an Internet MTA, and therefore handles addresses in
564RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
565simple two-component bang paths can be converted by a straightforward rewriting
566configuration. This restriction does not prevent Exim from being interfaced to
567UUCP as a transport mechanism, provided that domain addresses are used.
568.next
569.cindex "domainless addresses"
570.cindex "address" "without domain"
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571Exim insists that every address it handles has a domain attached. For incoming
572local messages, domainless addresses are automatically qualified with a
573configured domain value. Configuration options specify from which remote
574systems unqualified addresses are acceptable. These are then qualified on
575arrival.
9b371988
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576.next
577.cindex "transport" "external"
578.cindex "external transports"
579The only external transport mechanisms that are currently implemented are SMTP
580and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
168e428f 581transport is available, and there are facilities for writing messages to files
9b371988
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582and pipes, optionally in &'batched SMTP'& format; these facilities can be used
583to send messages to other transport mechanisms such as UUCP, provided they can
584handle domain-style addresses. Batched SMTP input is also catered for.
585.next
586Exim is not designed for storing mail for dial-in hosts. When the volumes of
587such mail are large, it is better to get the messages &"delivered"& into files
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588(that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
589other means.
9b371988
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590.next
591Although Exim does have basic facilities for scanning incoming messages, these
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592are not comprehensive enough to do full virus or spam scanning. Such operations
593are best carried out using additional specialized software packages. If you
594compile Exim with the content-scanning extension, straightforward interfaces to
595a number of common scanners are provided.
9b371988 596.endlist
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597
598
f89d2485 599.section "Run time configuration" "SECID7"
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600Exim's run time configuration is held in a single text file that is divided
601into a number of sections. The entries in this file consist of keywords and
602values, in the style of Smail 3 configuration files. A default configuration
603file which is suitable for simple online installations is provided in the
9b371988 604distribution, and is described in chapter &<<CHAPdefconfil>>& below.
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605
606
f89d2485 607.section "Calling interface" "SECID8"
9b371988 608.cindex "Sendmail compatibility" "command line interface"
168e428f 609Like many MTAs, Exim has adopted the Sendmail command line interface so that it
9b371988
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610can be a straight replacement for &_/usr/lib/sendmail_& or
611&_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
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612about Sendmail in order to run Exim. For actions other than sending messages,
613Sendmail-compatible options also exist, but those that produce output (for
9b371988 614example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
168e428f 615format. There are also some additional options that are compatible with Smail
9b371988 6163, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
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617documents all Exim's command line options. This information is automatically
618made into the man page that forms part of the Exim distribution.
619
620Control of messages on the queue can be done via certain privileged command
9b371988
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621line options. There is also an optional monitor program called &'eximon'&,
622which displays current information in an X window, and which contains a menu
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623interface to Exim's command line administration options.
624
625
626
f89d2485 627.section "Terminology" "SECID9"
9b371988
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628.cindex "terminology definitions"
629.cindex "body of message" "definition of"
630The &'body'& of a message is the actual data that the sender wants to transmit.
631It is the last part of a message, and is separated from the &'header'& (see
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632below) by a blank line.
633
9b371988 634.cindex "bounce message" "definition of"
168e428f 635When a message cannot be delivered, it is normally returned to the sender in a
9b371988
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636delivery failure message or a &"non-delivery report"& (NDR). The term
637&'bounce'& is commonly used for this action, and the error reports are often
638called &'bounce messages'&. This is a convenient shorthand for &"delivery
639failure error report"&. Such messages have an empty sender address in the
640message's &'envelope'& (see below) to ensure that they cannot themselves give
641rise to further bounce messages.
642
643The term &'default'& appears frequently in this manual. It is used to qualify a
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644value which is used in the absence of any setting in the configuration. It may
645also qualify an action which is taken unless a configuration setting specifies
646otherwise.
647
9b371988 648The term &'defer'& is used when the delivery of a message to a specific
168e428f 649destination cannot immediately take place for some reason (a remote host may be
9b371988 650down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
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651until a later time.
652
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653The word &'domain'& is sometimes used to mean all but the first component of a
654host's name. It is &'not'& used in that sense here, where it normally refers to
655the part of an email address following the @ sign.
168e428f 656
f89d2485 657.cindex "envelope, definition of"
9b371988
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658.cindex "sender" "definition of"
659A message in transit has an associated &'envelope'&, as well as a header and a
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660body. The envelope contains a sender address (to which bounce messages should
661be delivered), and any number of recipient addresses. References to the
662sender or the recipients of a message usually mean the addresses in the
663envelope. An MTA uses these addresses for delivery, and for returning bounce
664messages, not the addresses that appear in the header lines.
665
f89d2485 666.cindex "message" "header, definition of"
9b371988
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667.cindex "header section" "definition of"
668The &'header'& of a message is the first part of a message's text, consisting
669of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
670&'Subject:'&, etc. Long header lines can be split over several text lines by
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671indenting the continuations. The header is separated from the body by a blank
672line.
673
9b371988
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674.cindex "local part" "definition of"
675.cindex "domain" "definition of"
676The term &'local part'&, which is taken from RFC 2822, is used to refer to that
168e428f 677part of an email address that precedes the @ sign. The part that follows the
9b371988 678@ sign is called the &'domain'& or &'mail domain'&.
168e428f 679
9b371988 680.cindex "local delivery" "definition of"
f89d2485 681.cindex "remote delivery, definition of"
9b371988 682The terms &'local delivery'& and &'remote delivery'& are used to distinguish
168e428f 683delivery to a file or a pipe on the local host from delivery by SMTP over
068aaea8 684TCP/IP to another host. As far as Exim is concerned, all hosts other than the
9b371988 685host it is running on are &'remote'&.
168e428f 686
9b371988
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687.cindex "return path" "definition of"
688&'Return path'& is another name that is used for the sender address in a
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689message's envelope.
690
9b371988
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691.cindex "queue" "definition of"
692The term &'queue'& is used to refer to the set of messages awaiting delivery,
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693because this term is in widespread use in the context of MTAs. However, in
694Exim's case the reality is more like a pool than a queue, because there is
695normally no ordering of waiting messages.
696
9b371988
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697.cindex "queue runner" "definition of"
698The term &'queue runner'& is used to describe a process that scans the queue
168e428f 699and attempts to deliver those messages whose retry times have come. This term
9b371988 700is used by other MTAs, and also relates to the command &%runq%&, but in Exim
168e428f
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701the waiting messages are normally processed in an unpredictable order.
702
9b371988
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703.cindex "spool directory" "definition of"
704The term &'spool directory'& is used for a directory in which Exim keeps the
705messages on its queue &-- that is, those that it is in the process of
168e428f 706delivering. This should not be confused with the directory in which local
9b371988
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707mailboxes are stored, which is called a &"spool directory"& by some people. In
708the Exim documentation, &"spool"& is always used in the first sense.
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709
710
711
712
713
714
9b371988
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715. ////////////////////////////////////////////////////////////////////////////
716. ////////////////////////////////////////////////////////////////////////////
168e428f 717
f89d2485 718.chapter "Incorporated code" "CHID2"
9b371988
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719.cindex "incorporated code"
720.cindex "regular expressions" "library"
721.cindex "PCRE"
168e428f
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722A number of pieces of external code are included in the Exim distribution.
723
9b371988
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724.ilist
725Regular expressions are supported in the main Exim program and in the Exim
726monitor using the freely-distributable PCRE library, copyright &copy;
727University of Cambridge. The source is distributed in the directory
728&_src/pcre_&. However, this is a cut-down version of PCRE. If you want to use
729the PCRE library in other programs, you should obtain and install the full
f89d2485
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730version of the library from
731&url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
9b371988 732.next
f89d2485 733.cindex "cdb" "acknowledgment"
168e428f
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734Support for the cdb (Constant DataBase) lookup method is provided by code
735contributed by Nigel Metheringham of (at the time he contributed it) Planet
9b371988
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736Online Ltd. The implementation is completely contained within the code of Exim.
737It does not link against an external cdb library. The code contains the
738following statements:
739
740.blockquote
741Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
742
168e428f
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743This program is free software; you can redistribute it and/or modify it under
744the terms of the GNU General Public License as published by the Free Software
745Foundation; either version 2 of the License, or (at your option) any later
746version.
9b371988 747
168e428f
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748This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
749the spec and sample code for cdb can be obtained from
f89d2485
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750&url(http://www.pobox.com/~djb/cdb.html). This implementation borrows
751some code from Dan Bernstein's implementation (which has no license
752restrictions applied to it).
9b371988
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753.endblockquote
754.next
755.cindex "SPA authentication"
756.cindex "Samba project"
757.cindex "Microsoft Secure Password Authentication"
758Client support for Microsoft's &'Secure Password Authentication'& is provided
168e428f
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759by code contributed by Marc Prud'hommeaux. Server support was contributed by
760Tom Kistner. This includes code taken from the Samba project, which is released
761under the Gnu GPL.
9b371988
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762.next
763.cindex "Cyrus"
764.cindex "&'pwcheck'& daemon"
765.cindex "&'pwauthd'& daemon"
766Support for calling the Cyrus &'pwcheck'& and &'saslauthd'& daemons is provided
168e428f
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767by code taken from the Cyrus-SASL library and adapted by Alexander S.
768Sabourenkov. The permission notice appears below, in accordance with the
769conditions expressed therein.
9b371988
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770
771.blockquote
772Copyright &copy; 2001 Carnegie Mellon University. All rights reserved.
773
168e428f
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774Redistribution and use in source and binary forms, with or without
775modification, are permitted provided that the following conditions
776are met:
168e428f 777
9b371988
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778.olist
779Redistributions of source code must retain the above copyright
780notice, this list of conditions and the following disclaimer.
781.next
782Redistributions in binary form must reproduce the above copyright
168e428f
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783notice, this list of conditions and the following disclaimer in
784the documentation and/or other materials provided with the
785distribution.
9b371988
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786.next
787The name &"Carnegie Mellon University"& must not be used to
168e428f
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788endorse or promote products derived from this software without
789prior written permission. For permission or any other legal
790details, please contact
9b371988 791.display
068aaea8
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792 Office of Technology Transfer
793 Carnegie Mellon University
794 5000 Forbes Avenue
795 Pittsburgh, PA 15213-3890
796 (412) 268-4387, fax: (412) 268-7395
797 tech-transfer@andrew.cmu.edu
9b371988
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798.endd
799.next
800Redistributions of any form whatsoever must retain the following
168e428f 801acknowledgment:
9b371988
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802
803&"This product includes software developed by Computing Services
804at Carnegie Mellon University (&url(http://www.cmu.edu/computing/)."&
805
168e428f
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806CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
807THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
808AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
809FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
810WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
811AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
812OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
9b371988
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813.endlist
814.endblockquote
168e428f 815
9b371988 816.next
f89d2485 817.cindex "Exim monitor" "acknowledgment"
9b371988
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818.cindex "X-windows"
819.cindex "Athena"
168e428f
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820The Exim Monitor program, which is an X-Window application, includes
821modified versions of the Athena StripChart and TextPop widgets.
822This code is copyright by DEC and MIT, and their permission notice appears
823below, in accordance with the conditions expressed therein.
9b371988
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824
825.blockquote
168e428f
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826Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
827and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
9b371988 828
168e428f 829All Rights Reserved
9b371988 830
168e428f
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831Permission to use, copy, modify, and distribute this software and its
832documentation for any purpose and without fee is hereby granted,
833provided that the above copyright notice appear in all copies and that
834both that copyright notice and this permission notice appear in
835supporting documentation, and that the names of Digital or MIT not be
836used in advertising or publicity pertaining to distribution of the
837software without specific, written prior permission.
9b371988 838
168e428f
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839DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
840ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
841DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
842ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
843WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
844ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
845SOFTWARE.
9b371988 846.endblockquote
168e428f 847
9b371988
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848.next
849Many people have contributed code fragments, some large, some small, that were
168e428f 850not covered by any specific licence requirements. It is assumed that the
f89d2485 851contributors are happy to see their code incorporated into Exim under the GPL.
9b371988 852.endlist
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853
854
855
856
857
9b371988
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858. ////////////////////////////////////////////////////////////////////////////
859. ////////////////////////////////////////////////////////////////////////////
168e428f 860
f89d2485 861.chapter "How Exim receives and delivers mail" "CHID11" &&&
9b371988 862 "Receiving and delivering mail"
168e428f
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863
864
f89d2485 865.section "Overall philosophy" "SECID10"
9b371988 866.cindex "design philosophy"
168e428f
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867Exim is designed to work efficiently on systems that are permanently connected
868to the Internet and are handling a general mix of mail. In such circumstances,
869most messages can be delivered immediately. Consequently, Exim does not
870maintain independent queues of messages for specific domains or hosts, though
871it does try to send several messages in a single SMTP connection after a host
872has been down, and it also maintains per-host retry information.
873
874
f89d2485 875.section "Policy control" "SECID11"
9b371988 876.cindex "policy control" "overview"
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877Policy controls are now an important feature of MTAs that are connected to the
878Internet. Perhaps their most important job is to stop MTAs being abused as
9b371988
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879&"open relays"& by misguided individuals who send out vast amounts of
880unsolicited junk, and want to disguise its source. Exim provides flexible
881facilities for specifying policy controls on incoming mail:
168e428f 882
9b371988
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883.ilist
884.cindex "&ACL;" "introduction"
168e428f 885Exim 4 (unlike previous versions of Exim) implements policy controls on
9b371988 886incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
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887series of statements that may either grant or deny access. ACLs can be used at
888several places in the SMTP dialogue while receiving a message from a remote
9b371988
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889host. However, the most common places are after each RCPT command, and at the
890very end of the message. The sysadmin can specify conditions for accepting or
891rejecting individual recipients or the entire message, respectively, at these
892two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
168e428f 893error code.
9b371988
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894.next
895An ACL is also available for locally generated, non-SMTP messages. In this
168e428f 896case, the only available actions are to accept or deny the entire message.
9b371988
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897.next
898When Exim is compiled with the content-scanning extension, facilities are
168e428f
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899provided in the ACL mechanism for passing the message to external virus and/or
900spam scanning software. The result of such a scan is passed back to the ACL,
901which can then use it to decide what to do with the message.
9b371988
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902.next
903When a message has been received, either from a remote host or from the local
f89d2485 904host, but before the final acknowledgment has been sent, a locally supplied C
9b371988
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905function called &[local_scan()]& can be run to inspect the message and decide
906whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
907is accepted, the list of recipients can be modified by the function.
908.next
909Using the &[local_scan()]& mechanism is another way of calling external scanner
910software. The &%SA-Exim%& add-on package works this way. It does not require
911Exim to be compiled with the content-scanning extension.
912.next
913After a message has been accepted, a further checking mechanism is available in
914the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
915runs at the start of every delivery process.
916.endlist
917
918
919
f89d2485 920.section "User filters" "SECID12"
9b371988
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921.cindex "filter" "introduction"
922.cindex "Sieve filter"
168e428f 923In a conventional Exim configuration, users are able to run private filters by
9b371988
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924setting up appropriate &_.forward_& files in their home directories. See
925chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
926configuration needed to support this, and the separate document entitled
927&'Exim's interfaces to mail filtering'& for user details. Two different kinds
928of filtering are available:
929
930.ilist
931Sieve filters are written in the standard filtering language that is defined
168e428f 932by RFC 3028.
9b371988
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933.next
934Exim filters are written in a syntax that is unique to Exim, but which is more
168e428f 935powerful than Sieve, which it pre-dates.
9b371988 936.endlist
168e428f
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937
938User filters are run as part of the routing process, described below.
939
940
941
9b371988
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942.section "Message identification" "SECTmessiden"
943.cindex "message ids" "details of format"
944.cindex "format" "of message id"
945.cindex "id of message"
946.cindex "base62"
947.cindex "base36"
948.cindex "Darwin"
949.cindex "Cygwin"
950Every message handled by Exim is given a &'message id'& which is sixteen
168e428f 951characters long. It is divided into three parts, separated by hyphens, for
9b371988 952example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
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953normally encoding numbers in base 62. However, in the Darwin operating
954system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
955(avoiding the use of lower case letters) is used instead, because the message
956id is used to construct file names, and the names of files in those systems are
068aaea8 957not always case-sensitive.
168e428f 958
9b371988 959.cindex "pid (process id)" "re-use of"
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960The detail of the contents of the message id have changed as Exim has evolved.
961Earlier versions relied on the operating system not re-using a process id (pid)
962within one second. On modern operating systems, this assumption can no longer
963be made, so the algorithm had to be changed. To retain backward compatibility,
964the format of the message id was retained, which is why the following rules are
965somewhat eccentric:
966
9b371988
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967.ilist
968The first six characters of the message id are the time at which the message
168e428f
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969started to be received, to a granularity of one second. That is, this field
970contains the number of seconds since the start of the epoch (the normal Unix
971way of representing the date and time of day).
9b371988
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972.next
973After the first hyphen, the next six characters are the id of the process that
168e428f 974received the message.
9b371988
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975.next
976There are two different possibilities for the final two characters:
977.olist
978.cindex "&%localhost_number%&"
979If &%localhost_number%& is not set, this value is the fractional part of the
168e428f
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980time of reception, normally in units of 1/2000 of a second, but for systems
981that must use base 36 instead of base 62 (because of case-insensitive file
982systems), the units are 1/1000 of a second.
9b371988
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983.next
984If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
168e428f
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985the fractional part of the time, which in this case is in units of 1/200
986(1/100) of a second.
9b371988
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987.endlist
988.endlist
168e428f
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989
990After a message has been received, Exim waits for the clock to tick at the
991appropriate resolution before proceeding, so that if another message is
992received by the same process, or by another process with the same (re-used)
993pid, it is guaranteed that the time will be different. In most cases, the clock
994will already have ticked while the message was being received.
995
996
f89d2485 997.section "Receiving mail" "SECID13"
9b371988
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998.cindex "receiving mail"
999.cindex "message" "reception"
068aaea8
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1000The only way Exim can receive mail from another host is using SMTP over
1001TCP/IP, in which case the sender and recipient addresses are transferred using
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1002SMTP commands. However, from a locally running process (such as a user's MUA),
1003there are several possibilities:
1004
9b371988
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1005.ilist
1006If the process runs Exim with the &%-bm%& option, the message is read
168e428f 1007non-interactively (usually via a pipe), with the recipients taken from the
9b371988
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1008command line, or from the body of the message if &%-t%& is also used.
1009.next
1010If the process runs Exim with the &%-bS%& option, the message is also read
168e428f
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1011non-interactively, but in this case the recipients are listed at the start of
1012the message in a series of SMTP RCPT commands, terminated by a DATA
9b371988 1013command. This is so-called &"batch SMTP"& format,
168e428f
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1014but it isn't really SMTP. The SMTP commands are just another way of passing
1015envelope addresses in a non-interactive submission.
9b371988
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1016.next
1017If the process runs Exim with the &%-bs%& option, the message is read
168e428f
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1018interactively, using the SMTP protocol. A two-way pipe is normally used for
1019passing data between the local process and the Exim process.
9b371988 1020This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
168e428f 1021example, the ACLs for SMTP commands are used for this form of submission.
9b371988
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1022.next
1023A local process may also make a TCP/IP call to the host's loopback address
168e428f
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1024(127.0.0.1) or any other of its IP addresses. When receiving messages, Exim
1025does not treat the loopback address specially. It treats all such connections
1026in the same way as connections from other hosts.
9b371988 1027.endlist
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1028
1029
f89d2485 1030.cindex "message sender, constructed by Exim"
9b371988 1031.cindex "sender" "constructed by Exim"
168e428f
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1032In the three cases that do not involve TCP/IP, the sender address is
1033constructed from the login name of the user that called Exim and a default
9b371988 1034qualification domain (which can be set by the &%qualify_domain%& configuration
168e428f
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1035option). For local or batch SMTP, a sender address that is passed using the
1036SMTP MAIL command is ignored. However, the system administrator may allow
9b371988 1037certain users (&"trusted users"&) to specify a different sender address
168e428f 1038unconditionally, or all users to specify certain forms of different sender
9b371988
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1039address. The &%-f%& option or the SMTP MAIL command is used to specify these
1040different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1041users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
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1042users to change sender addresses.
1043
1044Messages received by either of the non-interactive mechanisms are subject to
1045checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1046(either over TCP/IP, or interacting with a local process) can be checked by a
1047number of ACLs that operate at different times during the SMTP session. Either
1048individual recipients, or the entire message, can be rejected if local policy
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1049requirements are not met. The &[local_scan()]& function (see chapter
1050&<<CHAPlocalscan>>&) is run for all incoming messages.
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1051
1052Exim can be configured not to start a delivery process when a message is
1053received; this can be unconditional, or depend on the number of incoming SMTP
1054connections or the system load. In these situations, new messages wait on the
1055queue until a queue runner process picks them up. However, in standard
1056configurations under normal conditions, delivery is started as soon as a
1057message is received.
1058
1059
1060
1061
1062
f89d2485 1063.section "Handling an incoming message" "SECID14"
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1064.cindex "spool directory" "files that hold a message"
1065.cindex "file" "how a message is held"
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1066When Exim accepts a message, it writes two files in its spool directory. The
1067first contains the envelope information, the current status of the message, and
1068the header lines, and the second contains the body of the message. The names of
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1069the two spool files consist of the message id, followed by &`-H`& for the
1070file containing the envelope and header, and &`-D`& for the data file.
168e428f 1071
9b371988 1072.cindex "spool directory" "&_input_& sub-directory"
168e428f 1073By default all these message files are held in a single directory called
9b371988 1074&_input_& inside the general Exim spool directory. Some operating systems do
c0712871 1075not perform very well if the number of files in a directory gets large; to
9b371988 1076improve performance in such cases, the &%split_spool_directory%& option can be
168e428f 1077used. This causes Exim to split up the input files into 62 sub-directories
db9452a9 1078whose names are single letters or digits. When this is done, the queue is
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1079processed one sub-directory at a time instead of all at once, which can improve
1080overall performance even when there are not enough files in each directory to
db9452a9 1081affect file system performance.
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1082
1083The envelope information consists of the address of the message's sender and
1084the addresses of the recipients. This information is entirely separate from
1085any addresses contained in the header lines. The status of the message includes
1086a list of recipients who have already received the message. The format of the
9b371988 1087first spool file is described in chapter &<<CHAPspool>>&.
168e428f 1088
9b371988 1089.cindex "rewriting" "addresses"
168e428f 1090Address rewriting that is specified in the rewrite section of the configuration
9b371988 1091(see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
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1092both in the header lines and the envelope, at the time the message is accepted.
1093If during the course of delivery additional addresses are generated (for
1094example, via aliasing), these new addresses are rewritten as soon as they are
1095generated. At the time a message is actually delivered (transported) further
1096rewriting can take place; because this is a transport option, it can be
1097different for different forms of delivery. It is also possible to specify the
1098addition or removal of certain header lines at the time the message is
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1099delivered (see chapters &<<CHAProutergeneric>>& and
1100&<<CHAPtransportgeneric>>&).
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1101
1102
1103
f89d2485 1104.section "Life of a message" "SECID15"
9b371988
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1105.cindex "message" "life of"
1106.cindex "message" "frozen"
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1107A message remains in the spool directory until it is completely delivered to
1108its recipients or to an error address, or until it is deleted by an
1109administrator or by the user who originally created it. In cases when delivery
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1110cannot proceed &-- for example, when a message can neither be delivered to its
1111recipients nor returned to its sender, the message is marked &"frozen"& on the
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1112spool, and no more deliveries are attempted.
1113
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1114.cindex "frozen messages" "thawing"
1115.cindex "message" "thawing frozen"
1116An administrator can &"thaw"& such messages when the problem has been
1117corrected, and can also freeze individual messages by hand if necessary. In
1118addition, an administrator can force a delivery error, causing a bounce message
1119to be sent.
1120
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1121.cindex "&%timeout_frozen_after%&"
1122.cindex "&%ignore_bounce_errors_after%&"
1123There are options called &%ignore_bounce_errors_after%& and
1124&%timeout_frozen_after%&, which discard frozen messages after a certain time.
068aaea8 1125The first applies only to frozen bounces, the second to any frozen messages.
168e428f 1126
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1127.cindex "message" "log file for"
1128.cindex "log" "file for each message"
168e428f 1129While Exim is working on a message, it writes information about each delivery
068aaea8 1130attempt to its main log file. This includes successful, unsuccessful, and
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1131delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1132lines are also written to a separate &'message log'& file for each message.
1133These logs are solely for the benefit of the administrator, and are normally
1134deleted along with the spool files when processing of a message is complete.
168e428f 1135The use of individual message logs can be disabled by setting
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1136&%no_message_logs%&; this might give an improvement in performance on very busy
1137systems.
168e428f 1138
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1139.cindex "journal file"
1140.cindex "file" "journal"
168e428f
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1141All the information Exim itself needs to set up a delivery is kept in the first
1142spool file, along with the header lines. When a successful delivery occurs, the
1143address is immediately written at the end of a journal file, whose name is the
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1144message id followed by &`-J`&. At the end of a delivery run, if there are some
1145addresses left to be tried again later, the first spool file (the &`-H`& file)
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1146is updated to indicate which these are, and the journal file is then deleted.
1147Updating the spool file is done by writing a new file and renaming it, to
1148minimize the possibility of data loss.
1149
1150Should the system or the program crash after a successful delivery but before
1151the spool file has been updated, the journal is left lying around. The next
1152time Exim attempts to deliver the message, it reads the journal file and
1153updates the spool file before proceeding. This minimizes the chances of double
1154deliveries caused by crashes.
1155
1156
1157
9b371988
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1158.section "Processing an address for delivery" "SECTprocaddress"
1159.cindex "drivers" "definition of"
1160.cindex "router" "definition of"
1161.cindex "transport" "definition of"
1162The main delivery processing elements of Exim are called &'routers'& and
1163&'transports'&, and collectively these are known as &'drivers'&. Code for a
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1164number of them is provided in the source distribution, and compile-time options
1165specify which ones are included in the binary. Run time options specify which
1166ones are actually used for delivering messages.
1167
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1168.cindex "drivers" "instance definition"
1169Each driver that is specified in the run time configuration is an &'instance'&
168e428f 1170of that particular driver type. Multiple instances are allowed; for example,
9b371988 1171you can set up several different &(smtp)& transports, each with different
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1172option values that might specify different ports or different timeouts. Each
1173instance has its own identifying name. In what follows we will normally use the
1174instance name when discussing one particular instance (that is, one specific
1175configuration of the driver), and the generic driver name when discussing
1176the driver's features in general.
1177
9b371988 1178A &'router'& is a driver that operates on an address, either determining how
068aaea8 1179its delivery should happen, by assigning it to a specific transport, or
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1180converting the address into one or more new addresses (for example, via an
1181alias file). A router may also explicitly choose to fail an address, causing it
1182to be bounced.
1183
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1184A &'transport'& is a driver that transmits a copy of the message from Exim's
1185spool to some destination. There are two kinds of transport: for a &'local'&
168e428f 1186transport, the destination is a file or a pipe on the local host, whereas for a
9b371988 1187&'remote'& transport the destination is some other host. A message is passed
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1188to a specific transport as a result of successful routing. If a message has
1189several recipients, it may be passed to a number of different transports.
1190
9b371988 1191.cindex "preconditions" "definition of"
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1192An address is processed by passing it to each configured router instance in
1193turn, subject to certain preconditions, until a router accepts the address or
1194specifies that it should be bounced. We will describe this process in more
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1195detail shortly. First, as a simple example, we consider how each recipient
1196address in a message is processed in a small configuration of three routers.
168e428f 1197
068aaea8 1198To make this a more concrete example, it is described in terms of some actual
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1199routers, but remember, this is only an example. You can configure Exim's
1200routers in many different ways, and there may be any number of routers in a
1201configuration.
1202
1203The first router that is specified in a configuration is often one that handles
1204addresses in domains that are not recognized specially by the local host. These
1205are typically addresses for arbitrary domains on the Internet. A precondition
1206is set up which looks for the special domains known to the host (for example,
9b371988 1207its own domain name), and the router is run for addresses that do &'not'&
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1208match. Typically, this is a router that looks up domains in the DNS in order to
1209find the hosts to which this address routes. If it succeeds, the address is
068aaea8 1210assigned to a suitable SMTP transport; if it does not succeed, the router is
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1211configured to fail the address.
1212
068aaea8 1213The second router is reached only when the domain is recognized as one that
9b371988 1214&"belongs"& to the local host. This router does redirection &-- also known as
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1215aliasing and forwarding. When it generates one or more new addresses from the
1216original, each of them is routed independently from the start. Otherwise, the
1217router may cause an address to fail, or it may simply decline to handle the
1218address, in which case the address is passed to the next router.
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1219
1220The final router in many configurations is one that checks to see if the
1221address belongs to a local mailbox. The precondition may involve a check to
1222see if the local part is the name of a login account, or it may look up the
1223local part in a file or a database. If its preconditions are not met, or if
1224the router declines, we have reached the end of the routers. When this happens,
1225the address is bounced.
1226
1227
1228
f89d2485 1229.section "Processing an address for verification" "SECID16"
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1230.cindex "router" "for verification"
1231.cindex "verifying address" "overview"
168e428f 1232As well as being used to decide how to deliver to an address, Exim's routers
9b371988 1233are also used for &'address verification'&. Verification can be requested as
168e428f 1234one of the checks to be performed in an ACL for incoming messages, on both
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1235sender and recipient addresses, and it can be tested using the &%-bv%& and
1236&%-bvs%& command line options.
168e428f 1237
9b371988 1238When an address is being verified, the routers are run in &"verify mode"&. This
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1239does not affect the way the routers work, but it is a state that can be
1240detected. By this means, a router can be skipped or made to behave differently
1241when verifying. A common example is a configuration in which the first router
1242sends all messages to a message-scanning program, unless they have been
1243previously scanned. Thus, the first router accepts all addresses without any
9b371988 1244checking, making it useless for verifying. Normally, the &%no_verify%& option
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1245would be set for such a router, causing it to be skipped in verify mode.
1246
1247
1248
1249
9b371988
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1250.section "Running an individual router" "SECTrunindrou"
1251.cindex "router" "running details"
1252.cindex "preconditions" "checking"
1253.cindex "router" "result of running"
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1254As explained in the example above, a number of preconditions are checked before
1255running a router. If any are not met, the router is skipped, and the address is
9b371988 1256passed to the next router. When all the preconditions on a router &'are'& met,
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1257the router is run. What happens next depends on the outcome, which is one of
1258the following:
1259
9b371988
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1260.ilist
1261&'accept'&: The router accepts the address, and either assigns it to a
1262transport, or generates one or more &"child"& addresses. Processing the
1263original address ceases,
1264.cindex "&%unseen%& option"
1265unless the &%unseen%& option is set on the router. This option
168e428f 1266can be used to set up multiple deliveries with different routing (for example,
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1267for keeping archive copies of messages). When &%unseen%& is set, the address is
1268passed to the next router. Normally, however, an &'accept'& return marks the
168e428f 1269end of routing.
9b371988 1270
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1271Any child addresses generated by the router are processed independently,
1272starting with the first router by default. It is possible to change this by
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1273setting the &%redirect_router%& option to specify which router to start at for
1274child addresses. Unlike &%pass_router%& (see below) the router specified by
1275&%redirect_router%& may be anywhere in the router configuration.
1276.next
1277&'pass'&: The router recognizes the address, but cannot handle it itself. It
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1278requests that the address be passed to another router. By default the address
1279is passed to the next router, but this can be changed by setting the
9b371988 1280&%pass_router%& option. However, (unlike &%redirect_router%&) the named router
168e428f 1281must be below the current router (to avoid loops).
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1282.next
1283&'decline'&: The router declines to accept the address because it does not
168e428f 1284recognize it at all. By default, the address is passed to the next router, but
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1285this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1286set, all the remaining routers are skipped. In effect, &%no_more%& converts
1287&'decline'& into &'fail'&.
1288.next
1289&'fail'&: The router determines that the address should fail, and queues it for
168e428f 1290the generation of a bounce message. There is no further processing of the
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1291original address unless &%unseen%& is set on the router.
1292.next
1293&'defer'&: The router cannot handle the address at the present time. (A
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1294database may be offline, or a DNS lookup may have timed out.) No further
1295processing of the address happens in this delivery attempt. It is tried again
1296next time the message is considered for delivery.
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1297.next
1298&'error'&: There is some error in the router (for example, a syntax error in
168e428f 1299its configuration). The action is as for defer.
9b371988 1300.endlist
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1301
1302If an address reaches the end of the routers without having been accepted by
068aaea8 1303any of them, it is bounced as unrouteable. The default error message in this
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1304situation is &"unrouteable address"&, but you can set your own message by
1305making use of the &%cannot_route_message%& option. This can be set for any
1306router; the value from the last router that &"saw"& the address is used.
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1307
1308Sometimes while routing you want to fail a delivery when some conditions are
1309met but others are not, instead of passing the address on for further routing.
1310You can do this by having a second router that explicitly fails the delivery
9b371988 1311when the relevant conditions are met. The &(redirect)& router has a &"fail"&
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1312facility for this purpose.
1313
1314
f89d2485 1315.section "Duplicate addresses" "SECID17"
9b371988 1316.cindex "case of local parts"
f89d2485 1317.cindex "address duplicate, discarding"
db9452a9 1318.cindex "duplicate addresses"
068aaea8
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1319Once routing is complete, Exim scans the addresses that are assigned to local
1320and remote transports, and discards any duplicates that it finds. During this
3cb1b51e 1321check, local parts are treated as case-sensitive. This happens only when
db9452a9 1322actually delivering a message; when testing routers with &%-bt%&, all the
3cb1b51e 1323routed addresses are shown.
db9452a9 1324
068aaea8 1325
168e428f 1326
9b371988 1327.section "Router preconditions" "SECTrouprecon"
f89d2485 1328.cindex "router" "preconditions, order of processing"
9b371988 1329.cindex "preconditions" "order of processing"
168e428f
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1330The preconditions that are tested for each router are listed below, in the
1331order in which they are tested. The individual configuration options are
9b371988 1332described in more detail in chapter &<<CHAProutergeneric>>&.
168e428f 1333
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1334.ilist
1335The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
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1336the local parts handled by the router may or must have certain prefixes and/or
1337suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1338skipped. These conditions are tested first. When an affix is present, it is
1339removed from the local part before further processing, including the evaluation
1340of any other conditions.
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1341.next
1342Routers can be designated for use only when not verifying an address, that is,
168e428f 1343only when routing it for delivery (or testing its delivery routing). If the
9b371988 1344&%verify%& option is set false, the router is skipped when Exim is verifying an
168e428f 1345address.
9b371988
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1346Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1347&%verify_recipient%&, which independently control the use of the router for
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1348sender and recipient verification. You can set these options directly if
1349you want a router to be used for only one type of verification.
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1350.next
1351If the &%address_test%& option is set false, the router is skipped when Exim is
1352run with the &%-bt%& option to test an address routing. This can be helpful
1353when the first router sends all new messages to a scanner of some sort; it
1354makes it possible to use &%-bt%& to test subsequent delivery routing without
1355having to simulate the effect of the scanner.
1356.next
1357Routers can be designated for use only when verifying an address, as
1358opposed to routing it for delivery. The &%verify_only%& option controls this.
1359.next
1360Individual routers can be explicitly skipped when running the routers to
1361check an address given in the SMTP EXPN command (see the &%expn%& option).
1362.next
1363If the &%domains%& option is set, the domain of the address must be in the set
068aaea8 1364of domains that it defines.
9b371988 1365.next
f89d2485
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1366.vindex "&$local_part_prefix$&"
1367.vindex "&$local_part$&"
1368.vindex "&$local_part_suffix$&"
9b371988
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1369If the &%local_parts%& option is set, the local part of the address must be in
1370the set of local parts that it defines. If &%local_part_prefix%& or
1371&%local_part_suffix%& is in use, the prefix or suffix is removed from the local
168e428f 1372part before this check. If you want to do precondition tests on local parts
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1373that include affixes, you can do so by using a &%condition%& option (see below)
1374that uses the variables &$local_part$&, &$local_part_prefix$&, and
1375&$local_part_suffix$& as necessary.
1376.next
f89d2485
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1377.vindex "&$local_user_uid$&"
1378.vindex "&$local_user_gid$&"
1379.vindex "&$home$&"
9b371988 1380If the &%check_local_user%& option is set, the local part must be the name of
068aaea8 1381an account on the local host. If this check succeeds, the uid and gid of the
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1382local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1383user's home directory is placed in &$home$&; these values can be used in the
1384remaining preconditions.
1385.next
1386If the &%router_home_directory%& option is set, it is expanded at this point,
1387because it overrides the value of &$home$&. If this expansion were left till
1388later, the value of &$home$& as set by &%check_local_user%& would be used in
1389subsequent tests. Having two different values of &$home$& in the same router
168e428f 1390could lead to confusion.
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1391.next
1392If the &%senders%& option is set, the envelope sender address must be in the
1393set of addresses that it defines.
1394.next
1395If the &%require_files%& option is set, the existence or non-existence of
168e428f 1396specified files is tested.
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1397.next
1398.cindex "customizing" "precondition"
1399If the &%condition%& option is set, it is evaluated and tested. This option
1400uses an expanded string to allow you to set up your own custom preconditions.
1401Expanded strings are described in chapter &<<CHAPexpand>>&.
1402.endlist
168e428f 1403
168e428f 1404
9b371988
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1405Note that &%require_files%& comes near the end of the list, so you cannot use
1406it to check for the existence of a file in which to lookup up a domain, local
168e428f 1407part, or sender. However, as these options are all expanded, you can use the
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1408&%exists%& expansion condition to make such tests within each condition. The
1409&%require_files%& option is intended for checking files that the router may be
168e428f 1410going to use internally, or which are needed by a specific transport (for
9b371988 1411example, &_.procmailrc_&).
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1412
1413
1414
f89d2485 1415.section "Delivery in detail" "SECID18"
9b371988 1416.cindex "delivery" "in detail"
168e428f
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1417When a message is to be delivered, the sequence of events is as follows:
1418
9b371988
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1419.ilist
1420If a system-wide filter file is specified, the message is passed to it. The
168e428f
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1421filter may add recipients to the message, replace the recipients, discard the
1422message, cause a new message to be generated, or cause the message delivery to
1423fail. The format of the system filter file is the same as for Exim user filter
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1424files, described in the separate document entitled &'Exim's interfaces to mail
1425filtering'&.
1426.cindex "Sieve filter" "not available for system filter"
1427(&*Note*&: Sieve cannot be used for system filter files.)
1428
1429Some additional features are available in system filters &-- see chapter
1430&<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
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1431filter only once per delivery attempt, however many recipients it has. However,
1432if there are several delivery attempts because one or more addresses could not
1433be immediately delivered, the system filter is run each time. The filter
9b371988 1434condition &%first_delivery%& can be used to detect the first run of the system
168e428f 1435filter.
9b371988
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1436.next
1437Each recipient address is offered to each configured router in turn, subject to
1438its preconditions, until one is able to handle it. If no router can handle the
1439address, that is, if they all decline, the address is failed. Because routers
1440can be targeted at particular domains, several locally handled domains can be
1441processed entirely independently of each other.
1442.next
1443.cindex "routing" "loops in"
1444.cindex "loop" "while routing"
1445A router that accepts an address may assign it to a local or a remote
1446transport. However, the transport is not run at this time. Instead, the address
1447is placed on a list for the particular transport, which will be run later.
068aaea8
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1448Alternatively, the router may generate one or more new addresses (typically
1449from alias, forward, or filter files). New addresses are fed back into this
1450process from the top, but in order to avoid loops, a router ignores any address
1451which has an identically-named ancestor that was processed by itself.
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1452.next
1453When all the routing has been done, addresses that have been successfully
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1454handled are passed to their assigned transports. When local transports are
1455doing real local deliveries, they handle only one address at a time, but if a
1456local transport is being used as a pseudo-remote transport (for example, to
1457collect batched SMTP messages for transmission by some other means) multiple
1458addresses can be handled. Remote transports can always handle more than one
1459address at a time, but can be configured not to do so, or to restrict multiple
1460addresses to the same domain.
9b371988
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1461.next
1462Each local delivery to a file or a pipe runs in a separate process under a
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1463non-privileged uid, and these deliveries are run one at a time. Remote
1464deliveries also run in separate processes, normally under a uid that is private
9b371988 1465to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
168e428f 1466run in parallel. The maximum number of simultaneous remote deliveries for any
9b371988 1467one message is set by the &%remote_max_parallel%& option.
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1468The order in which deliveries are done is not defined, except that all local
1469deliveries happen before any remote deliveries.
9b371988
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1470.next
1471.cindex "queue runner"
168e428f
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1472When it encounters a local delivery during a queue run, Exim checks its retry
1473database to see if there has been a previous temporary delivery failure for the
1474address before running the local transport. If there was a previous failure,
1475Exim does not attempt a new delivery until the retry time for the address is
1476reached. However, this happens only for delivery attempts that are part of a
1477queue run. Local deliveries are always attempted when delivery immediately
1478follows message reception, even if retry times are set for them. This makes for
1479better behaviour if one particular message is causing problems (for example,
1480causing quota overflow, or provoking an error in a filter file).
9b371988
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1481.next
1482.cindex "delivery" "retry in remote transports"
168e428f
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1483Remote transports do their own retry handling, since an address may be
1484deliverable to one of a number of hosts, each of which may have a different
1485retry time. If there have been previous temporary failures and no host has
1486reached its retry time, no delivery is attempted, whether in a queue run or
9b371988
PH
1487not. See chapter &<<CHAPretry>>& for details of retry strategies.
1488.next
1489If there were any permanent errors, a bounce message is returned to an
168e428f
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1490appropriate address (the sender in the common case), with details of the error
1491for each failing address. Exim can be configured to send copies of bounce
1492messages to other addresses.
9b371988
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1493.next
1494.cindex "delivery" "deferral"
168e428f
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1495If one or more addresses suffered a temporary failure, the message is left on
1496the queue, to be tried again later. Delivery of these addresses is said to be
9b371988
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1497&'deferred'&.
1498.next
1499When all the recipient addresses have either been delivered or bounced,
168e428f
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1500handling of the message is complete. The spool files and message log are
1501deleted, though the message log can optionally be preserved if required.
9b371988 1502.endlist
168e428f
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1503
1504
1505
1506
f89d2485 1507.section "Retry mechanism" "SECID19"
9b371988
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1508.cindex "delivery" "retry mechanism"
1509.cindex "retry" "description of mechanism"
1510.cindex "queue runner"
168e428f
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1511Exim's mechanism for retrying messages that fail to get delivered at the first
1512attempt is the queue runner process. You must either run an Exim daemon that
9b371988
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1513uses the &%-q%& option with a time interval to start queue runners at regular
1514intervals, or use some other means (such as &'cron'&) to start them. If you do
168e428f
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1515not arrange for queue runners to be run, messages that fail temporarily at the
1516first attempt will remain on your queue for ever. A queue runner process works
068aaea8 1517its way through the queue, one message at a time, trying each delivery that has
168e428f
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1518passed its retry time.
1519You can run several queue runners at once.
1520
1521Exim uses a set of configured rules to determine when next to retry the failing
9b371988
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1522address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1523should give up trying to deliver to the address, at which point it generates a
1524bounce message. If no retry rules are set for a particular host, address, and
1525error combination, no retries are attempted, and temporary errors are treated
1526as permanent.
168e428f
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1527
1528
1529
f89d2485 1530.section "Temporary delivery failure" "SECID20"
9b371988 1531.cindex "delivery" "temporary failure"
168e428f
PH
1532There are many reasons why a message may not be immediately deliverable to a
1533particular address. Failure to connect to a remote machine (because it, or the
1534connection to it, is down) is one of the most common. Temporary failures may be
1535detected during routing as well as during the transport stage of delivery.
1536Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1537is on a file system where the user is over quota. Exim can be configured to
1538impose its own quotas on local mailboxes; where system quotas are set they will
1539also apply.
1540
1541If a host is unreachable for a period of time, a number of messages may be
1542waiting for it by the time it recovers, and sending them in a single SMTP
1543connection is clearly beneficial. Whenever a delivery to a remote host is
1544deferred,
1545
9b371988 1546.cindex "hints database"
168e428f
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1547Exim makes a note in its hints database, and whenever a successful
1548SMTP delivery has happened, it looks to see if any other messages are waiting
1549for the same host. If any are found, they are sent over the same SMTP
1550connection, subject to a configuration limit as to the maximum number in any
1551one connection.
1552
1553
1554
1555
f89d2485 1556.section "Permanent delivery failure" "SECID21"
9b371988
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1557.cindex "delivery" "permanent failure"
1558.cindex "bounce message" "when generated"
168e428f
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1559When a message cannot be delivered to some or all of its intended recipients, a
1560bounce message is generated. Temporary delivery failures turn into permanent
1561errors when their timeout expires. All the addresses that fail in a given
1562delivery attempt are listed in a single message. If the original message has
1563many recipients, it is possible for some addresses to fail in one delivery
1564attempt and others to fail subsequently, giving rise to more than one bounce
1565message. The wording of bounce messages can be customized by the administrator.
9b371988 1566See chapter &<<CHAPemsgcust>>& for details.
168e428f 1567
9b371988
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1568.cindex "&'X-Failed-Recipients:'& header line"
1569Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
168e428f
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1570failed addresses, for the benefit of programs that try to analyse such messages
1571automatically.
1572
9b371988 1573.cindex "bounce message" "recipient of"
168e428f
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1574A bounce message is normally sent to the sender of the original message, as
1575obtained from the message's envelope. For incoming SMTP messages, this is the
9b371988
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1576address given in the MAIL command. However, when an address is expanded via a
1577forward or alias file, an alternative address can be specified for delivery
1578failures of the generated addresses. For a mailing list expansion (see section
1579&<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1580of the list.
168e428f
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1581
1582
1583
f89d2485 1584.section "Failures to deliver bounce messages" "SECID22"
9b371988 1585.cindex "bounce message" "failure to deliver"
168e428f
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1586If a bounce message (either locally generated or received from a remote host)
1587itself suffers a permanent delivery failure, the message is left on the queue,
1588but it is frozen, awaiting the attention of an administrator. There are options
068aaea8 1589that can be used to make Exim discard such failed messages, or to keep them
9b371988
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1590for only a short time (see &%timeout_frozen_after%& and
1591&%ignore_bounce_errors_after%&).
168e428f
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1592
1593
1594
1595
1596
9b371988
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1597. ////////////////////////////////////////////////////////////////////////////
1598. ////////////////////////////////////////////////////////////////////////////
168e428f 1599
f89d2485 1600.chapter "Building and installing Exim" "CHID3"
4f578862 1601.scindex IIDbuex "building Exim"
168e428f 1602
f89d2485
PH
1603.section "Unpacking" "SECID23"
1604Exim is distributed as a gzipped or bzipped tar file which, when unpacked,
168e428f 1605creates a directory with the name of the current release (for example,
9b371988
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1606&_exim-&version;_&) into which the following files are placed:
1607
1608.table2 140pt
f89d2485
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1609.irow &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1610.irow &_CHANGES_& "contains a reference to where changes are &&&
1611 documented"
1612.irow &_LICENCE_& "the GNU General Public Licence"
1613.irow &_Makefile_& "top-level make file"
1614.irow &_NOTICE_& "conditions for the use of Exim"
1615.irow &_README_& "list of files, directories and simple build &&&
1616 instructions"
9b371988
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1617.endtable
1618
1619Other files whose names begin with &_README_& may also be present. The
168e428f
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1620following subdirectories are created:
1621
9b371988 1622.table2 140pt
f89d2485
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1623.irow &_Local_& "an empty directory for local configuration files"
1624.irow &_OS_& "OS-specific files"
1625.irow &_doc_& "documentation files"
1626.irow &_exim_monitor_& "source files for the Exim monitor"
1627.irow &_scripts_& "scripts used in the build process"
1628.irow &_src_& "remaining source files"
1629.irow &_util_& "independent utilities"
9b371988
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1630.endtable
1631
1632The main utility programs are contained in the &_src_& directory, and are built
1633with the Exim binary. The &_util_& directory contains a few optional scripts
168e428f
PH
1634that may be useful to some sites.
1635
1636
f89d2485 1637.section "Multiple machine architectures and operating systems" "SECID24"
9b371988 1638.cindex "building Exim" "multiple OS/architectures"
168e428f
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1639The building process for Exim is arranged to make it easy to build binaries for
1640a number of different architectures and operating systems from the same set of
9b371988
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1641source files. Compilation does not take place in the &_src_& directory.
1642Instead, a &'build directory'& is created for each architecture and operating
1643system.
1644.cindex "symbolic link" "to build directory"
168e428f 1645Symbolic links to the sources are installed in this directory, which is where
9b371988
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1646the actual building takes place. In most cases, Exim can discover the machine
1647architecture and operating system for itself, but the defaults can be
1648overridden if necessary.
168e428f 1649
168e428f 1650
9b371988
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1651.section "DBM libraries" "SECTdb"
1652.cindex "DBM libraries" "discussion of"
1653.cindex "hints database" "DBM files used for"
168e428f
PH
1654Even if you do not use any DBM files in your configuration, Exim still needs a
1655DBM library in order to operate, because it uses indexed files for its hints
1656databases. Unfortunately, there are a number of DBM libraries in existence, and
1657different operating systems often have different ones installed.
1658
9b371988 1659.cindex "Solaris" "DBM library for"
f89d2485
PH
1660.cindex "IRIX, DBM library for"
1661.cindex "BSD, DBM library for"
1662.cindex "Linux, DBM library for"
168e428f
PH
1663If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1664Linux distribution, the DBM configuration should happen automatically, and you
1665may be able to ignore this section. Otherwise, you may have to learn more than
1666you would like about DBM libraries from what follows.
1667
9b371988 1668.cindex "&'ndbm'& DBM library"
168e428f 1669Licensed versions of Unix normally contain a library of DBM functions operating
9b371988 1670via the &'ndbm'& interface, and this is what Exim expects by default. Free
168e428f
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1671versions of Unix seem to vary in what they contain as standard. In particular,
1672some early versions of Linux have no default DBM library, and different
1673distributors have chosen to bundle different libraries with their packaged
f89d2485 1674versions. However, the more recent releases seem to have standardized on the
168e428f
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1675Berkeley DB library.
1676
1677Different DBM libraries have different conventions for naming the files they
9b371988 1678use. When a program opens a file called &_dbmfile_&, there are several
168e428f
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1679possibilities:
1680
9b371988
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1681.olist
1682A traditional &'ndbm'& implementation, such as that supplied as part of
1683Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1684.next
1685.cindex "&'gdbm'& DBM library"
1686The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
168e428f 1687compatibility interface it makes two different hard links to it with names
9b371988 1688&_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
168e428f 1689file name is used unmodified.
9b371988
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1690.next
1691.cindex "Berkeley DB library"
1692The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1693operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1694programmer exactly the same as the traditional &'ndbm'& implementation.
1695.next
1696If the Berkeley package is used in its native mode, it operates on a single
1697file called &_dbmfile_&; the programmer's interface is somewhat different to
1698the traditional &'ndbm'& interface.
1699.next
1700To complicate things further, there are several very different versions of the
168e428f 1701Berkeley DB package. Version 1.85 was stable for a very long time, releases
9b371988
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17022.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1703numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
168e428f 1704versions of Berkeley DB can be obtained from
9b371988
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1705&url(http://www.sleepycat.com/).
1706.next
1707.cindex "&'tdb'& DBM library"
1708Yet another DBM library, called &'tdb'&, is available from
1709&url(http://download.sourceforge.net/tdb). It has its own interface, and also
1710operates on a single file.
1711.endlist
1712
1713.cindex "USE_DB"
1714.cindex "DBM libraries" "configuration for building"
168e428f
PH
1715Exim and its utilities can be compiled to use any of these interfaces. In order
1716to use any version of the Berkeley DB package in native mode, you must set
1717USE_DB in an appropriate configuration file (typically
9b371988
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1718&_Local/Makefile_&). For example:
1719.code
1720USE_DB=yes
1721.endd
168e428f
PH
1722Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1723error is diagnosed if you set more than one of these.
1724
1725At the lowest level, the build-time configuration sets none of these options,
1726thereby assuming an interface of type (1). However, some operating system
1727configuration files (for example, those for the BSD operating systems and
1728Linux) assume type (4) by setting USE_DB as their default, and the
1729configuration files for Cygwin set USE_GDBM. Anything you set in
9b371988 1730&_Local/Makefile_&, however, overrides these system defaults.
168e428f
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1731
1732As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1733necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1734in one of these lines:
9b371988
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1735.code
1736DBMLIB = -ldb
1737DBMLIB = -ltdb
1738.endd
168e428f
PH
1739Settings like that will work if the DBM library is installed in the standard
1740place. Sometimes it is not, and the library's header file may also not be in
1741the default path. You may need to set INCLUDE to specify where the header
1742file is, and to specify the path to the library more fully in DBMLIB, as in
1743this example:
9b371988
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1744.code
1745INCLUDE=-I/usr/local/include/db-4.1
1746DBMLIB=/usr/local/lib/db-4.1/libdb.a
1747.endd
168e428f 1748There is further detailed discussion about the various DBM libraries in the
9b371988 1749file &_doc/dbm.discuss.txt_& in the Exim distribution.
168e428f
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1750
1751
1752
f89d2485 1753.section "Pre-building configuration" "SECID25"
9b371988
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1754.cindex "building Exim" "pre-building configuration"
1755.cindex "configuration for building Exim"
1756.cindex "&_Local/Makefile_&"
1757.cindex "&_src/EDITME_&"
168e428f
PH
1758Before building Exim, a local configuration file that specifies options
1759independent of any operating system has to be created with the name
9b371988
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1760&_Local/Makefile_&. A template for this file is supplied as the file
1761&_src/EDITME_&, and it contains full descriptions of all the option settings
168e428f
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1762therein. These descriptions are therefore not repeated here. If you are
1763building Exim for the first time, the simplest thing to do is to copy
9b371988 1764&_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
168e428f
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1765
1766There are three settings that you must supply, because Exim will not build
1767without them. They are the location of the run time configuration file
1768(CONFIGURE_FILE), the directory in which Exim binaries will be installed
1769(BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1770maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1771a colon-separated list of file names; Exim uses the first of them that exists.
1772
1773There are a few other parameters that can be specified either at build time or
1774at run time, to enable the same binary to be used on a number of different
1775machines. However, if the locations of Exim's spool directory and log file
1776directory (if not within the spool directory) are fixed, it is recommended that
9b371988 1777you specify them in &_Local/Makefile_& instead of at run time, so that errors
168e428f
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1778detected early in Exim's execution (such as a malformed configuration file) can
1779be logged.
1780
9b371988 1781.cindex "content scanning" "specifying at build time"
068aaea8 1782Exim's interfaces for calling virus and spam scanning software directly from
168e428f
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1783access control lists are not compiled by default. If you want to include these
1784facilities, you need to set
9b371988
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1785.code
1786WITH_CONTENT_SCAN=yes
1787.endd
1788in your &_Local/Makefile_&. For details of the facilities themselves, see
1789chapter &<<CHAPexiscan>>&.
168e428f
PH
1790
1791
9b371988 1792.cindex "&_Local/eximon.conf_&"
3cb1b51e 1793.cindex "&_exim_monitor/EDITME_&"
168e428f 1794If you are going to build the Exim monitor, a similar configuration process is
9b371988
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1795required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1796your installation and saved under the name &_Local/eximon.conf_&. If you are
1797happy with the default settings described in &_exim_monitor/EDITME_&,
1798&_Local/eximon.conf_& can be empty, but it must exist.
168e428f
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1799
1800This is all the configuration that is needed in straightforward cases for known
1801operating systems. However, the building process is set up so that it is easy
1802to override options that are set by default or by operating-system-specific
1803configuration files, for example to change the name of the C compiler, which
9b371988
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1804defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1805do this.
168e428f
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1806
1807
1808
f89d2485 1809.section "Support for iconv()" "SECID26"
9b371988
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1810.cindex "&[iconv()]& support"
1811.cindex "RFC 2047"
168e428f
PH
1812The contents of header lines in messages may be encoded according to the rules
1813described RFC 2047. This makes it possible to transmit characters that are not
1814in the ASCII character set, and to label them as being in a particular
9b371988 1815character set. When Exim is inspecting header lines by means of the &%$h_%&
168e428f
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1816mechanism, it decodes them, and translates them into a specified character set
1817(default ISO-8859-1). The translation is possible only if the operating system
9b371988
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1818supports the &[iconv()]& function.
1819
1820However, some of the operating systems that supply &[iconv()]& do not support
1821very many conversions. The GNU &%libiconv%& library (available from
1822&url(http://www.gnu.org/software/libiconv/)) can be installed on such
1823systems to remedy this deficiency, as well as on systems that do not supply
1824&[iconv()]& at all. After installing &%libiconv%&, you should add
1825.code
1826HAVE_ICONV=yes
1827.endd
1828to your &_Local/Makefile_& and rebuild Exim.
1829
1830
1831
1832.section "Including TLS/SSL encryption support" "SECTinctlsssl"
1833.cindex "TLS" "including support for TLS"
1834.cindex "encryption" "including support for"
1835.cindex "SUPPORT_TLS"
1836.cindex "OpenSSL" "building Exim with"
1837.cindex "GnuTLS" "building Exim with"
168e428f
PH
1838Exim can be built to support encrypted SMTP connections, using the STARTTLS
1839command as per RFC 2487. It can also support legacy clients that expect to
1840start a TLS session immediately on connection to a non-standard port (see the
9b371988 1841&%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
168e428f
PH
1842line option).
1843
1844If you want to build Exim with TLS support, you must first install either the
1845OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1846implementing SSL.
1847
1848If OpenSSL is installed, you should set
9b371988
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1849.code
1850SUPPORT_TLS=yes
1851TLS_LIBS=-lssl -lcrypto
1852.endd
1853in &_Local/Makefile_&. You may also need to specify the locations of the
168e428f 1854OpenSSL library and include files. For example:
9b371988
PH
1855.code
1856SUPPORT_TLS=yes
1857TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1858TLS_INCLUDE=-I/usr/local/openssl/include/
1859.endd
1860.cindex "USE_GNUTLS"
168e428f 1861If GnuTLS is installed, you should set
9b371988
PH
1862.code
1863SUPPORT_TLS=yes
1864USE_GNUTLS=yes
1865TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1866.endd
1867in &_Local/Makefile_&, and again you may need to specify the locations of the
168e428f 1868library and include files. For example:
9b371988
PH
1869.code
1870SUPPORT_TLS=yes
1871USE_GNUTLS=yes
1872TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1873TLS_INCLUDE=-I/usr/gnu/include
1874.endd
168e428f 1875You do not need to set TLS_INCLUDE if the relevant directory is already
9b371988
PH
1876specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1877given in chapter &<<CHAPTLS>>&.
168e428f
PH
1878
1879
1880
1881
f89d2485
PH
1882.section "Use of tcpwrappers" "SECID27"
1883.cindex "tcpwrappers, building Exim to support"
9b371988
PH
1884.cindex "USE_TCP_WRAPPERS"
1885Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1886SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
168e428f 1887alternative to Exim's own checking facilities for installations that are
9b371988
PH
1888already making use of &'tcpwrappers'& for other purposes. To do this, you
1889should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1890&_tcpd.h_& to be available at compile time, and also ensure that the library
1891&_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1892EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1893you might have
1894.code
1895USE_TCP_WRAPPERS=yes
1896CFLAGS=-O -I/usr/local/include
1897EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1898.endd
1899in &_Local/Makefile_&. The name to use in the &'tcpwrappers'& control files is
1900&"exim"&. For example, the line
1901.code
1902exim : LOCAL 192.168.1. .friendly.domain.example
1903.endd
1904in your &_/etc/hosts.allow_& file allows connections from the local host, from
1905the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&.
1906All other connections are denied. Consult the &'tcpwrappers'& documentation for
168e428f
PH
1907further details.
1908
1909
1910
f89d2485 1911.section "Including support for IPv6" "SECID28"
9b371988 1912.cindex "IPv6" "including support for"
168e428f 1913Exim contains code for use on systems that have IPv6 support. Setting
9b371988 1914&`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
168e428f
PH
1915it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1916where the IPv6 support is not fully integrated into the normal include and
1917library files.
1918
1919Two different types of DNS record for handling IPv6 addresses have been
f89d2485 1920defined. AAAA records (analogous to A records for IPv4) are in use, and are
168e428f
PH
1921currently seen as the mainstream. Another record type called A6 was proposed
1922as better than AAAA because it had more flexibility. However, it was felt to be
9b371988 1923over-complex, and its status was reduced to &"experimental"&. It is not known
168e428f 1924if anyone is actually using A6 records. Exim has support for A6 records, but
9b371988 1925this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
168e428f
PH
1926support has not been tested for some time.
1927
1928
1929
f89d2485 1930.section "The building process" "SECID29"
9b371988
PH
1931.cindex "build directory"
1932Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
1933created, run &'make'& at the top level. It determines the architecture and
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1934operating system types, and creates a build directory if one does not exist.
1935For example, on a Sun system running Solaris 8, the directory
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1936&_build-SunOS5-5.8-sparc_& is created.
1937.cindex "symbolic link" "to source files"
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1938Symbolic links to relevant source files are installed in the build directory.
1939
9b371988 1940&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
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1941building process fails if it is set.
1942
9b371988 1943If this is the first time &'make'& has been run, it calls a script that builds
168e428f 1944a make file inside the build directory, using the configuration files from the
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1945&_Local_& directory. The new make file is then passed to another instance of
1946&'make'&. This does the real work, building a number of utility scripts, and
168e428f 1947then compiling and linking the binaries for the Exim monitor (if configured), a
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1948number of utility programs, and finally Exim itself. The command &`make
1949makefile`& can be used to force a rebuild of the make file in the build
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1950directory, should this ever be necessary.
1951
1952If you have problems building Exim, check for any comments there may be in the
9b371988 1953&_README_& file concerning your operating system, and also take a look at the
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1954FAQ, where some common problems are covered.
1955
1956
1957
f89d2485 1958.section 'Output from &"make"&' "SECID283"
9b371988 1959The output produced by the &'make'& process for compile lines is often very
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1960unreadable, because these lines can be very long. For this reason, the normal
1961output is suppressed by default, and instead output similar to that which
1962appears when compiling the 2.6 Linux kernel is generated: just a short line for
1963each module that is being compiled or linked. However, it is still possible to
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1964get the full output, by calling &'make'& like this:
1965.code
1966FULLECHO='' make -e
1967.endd
1968The value of FULLECHO defaults to &"@"&, the flag character that suppresses
1969command reflection in &'make'&. When you ask for the full output, it is
3cb1b51e 1970given in addition to the short output.
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1971
1972
1973
9b371988 1974.section "Overriding build-time options for Exim" "SECToverride"
f89d2485 1975.cindex "build-time options, overriding"
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1976The main make file that is created at the beginning of the building process
1977consists of the concatenation of a number of files which set configuration
9b371988 1978values, followed by a fixed set of &'make'& instructions. If a value is set
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1979more than once, the last setting overrides any previous ones. This provides a
1980convenient way of overriding defaults. The files that are concatenated are, in
1981order:
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1982.display
1983&_OS/Makefile-Default_&
1984&_OS/Makefile-_&<&'ostype'&>
1985&_Local/Makefile_&
1986&_Local/Makefile-_&<&'ostype'&>
1987&_Local/Makefile-_&<&'archtype'&>
1988&_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
1989&_OS/Makefile-Base_&
1990.endd
1991.cindex "&_Local/Makefile_&"
1992.cindex "building Exim" "operating system type"
1993.cindex "building Exim" "architecture type"
1994where <&'ostype'&> is the operating system type and <&'archtype'&> is the
1995architecture type. &_Local/Makefile_& is required to exist, and the building
1996process fails if it is absent. The other three &_Local_& files are optional,
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1997and are often not needed.
1998
9b371988
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1999The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
2000called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
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2001the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
2002values are used, thereby providing a means of forcing particular settings.
9b371988 2003Otherwise, the scripts try to get values from the &%uname%& command. If this
168e428f 2004fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
9b371988 2005of &'ad hoc'& transformations are then applied, to produce the standard names
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2006that Exim expects. You can run these scripts directly from the shell in order
2007to find out what values are being used on your system.
2008
2009
9b371988 2010&_OS/Makefile-Default_& contains comments about the variables that are set
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2011therein. Some (but not all) are mentioned below. If there is something that
2012needs changing, review the contents of this file and the contents of the make
9b371988 2013file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
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2014default values are.
2015
2016
9b371988
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2017.cindex "building Exim" "overriding default settings"
2018If you need to change any of the values that are set in &_OS/Makefile-Default_&
2019or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
168e428f 2020need to change the original files. Instead, you should make the changes by
9b371988
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2021putting the new values in an appropriate &_Local_& file. For example,
2022.cindex "Tru64-Unix build-time settings"
168e428f
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2023when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2024formerly DEC-OSF1) operating system, it is necessary to specify that the C
9b371988
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2025compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2026called with the option &%-std1%&, to make it recognize some of the features of
168e428f 2027Standard C that Exim uses. (Most other compilers recognize Standard C by
9b371988 2028default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
168e428f 2029containing the lines
9b371988
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2030.code
2031CC=cc
2032CFLAGS=-std1
2033.endd
168e428f 2034If you are compiling for just one operating system, it may be easier to put
9b371988 2035these lines directly into &_Local/Makefile_&.
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2036
2037Keeping all your local configuration settings separate from the distributed
2038files makes it easy to transfer them to new versions of Exim simply by copying
9b371988 2039the contents of the &_Local_& directory.
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2040
2041
9b371988
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2042.cindex "NIS lookup type" "including support for"
2043.cindex "NIS+ lookup type" "including support for"
2044.cindex "LDAP" "including support for"
2045.cindex "lookup" "inclusion in binary"
168e428f
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2046Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2047lookup, but not all systems have these components installed, so the default is
2048not to include the relevant code in the binary. All the different kinds of file
2049and database lookup that Exim supports are implemented as separate code modules
2050which are included only if the relevant compile-time options are set. In the
9b371988
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2051case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2052.code
2053LOOKUP_LDAP=yes
2054LOOKUP_NIS=yes
2055LOOKUP_NISPLUS=yes
2056.endd
168e428f 2057and similar settings apply to the other lookup types. They are all listed in
9b371988 2058&_src/EDITME_&. In many cases the relevant include files and interface
168e428f 2059libraries need to be installed before compiling Exim.
9b371988 2060.cindex "cdb" "including support for"
068aaea8
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2061However, there are some optional lookup types (such as cdb) for which
2062the code is entirely contained within Exim, and no external include
168e428f
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2063files or libraries are required. When a lookup type is not included in the
2064binary, attempts to configure Exim to use it cause run time configuration
2065errors.
2066
9b371988 2067.cindex "Perl" "including support for"
168e428f
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2068Exim can be linked with an embedded Perl interpreter, allowing Perl
2069subroutines to be called during string expansion. To enable this facility,
9b371988
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2070.code
2071EXIM_PERL=perl.o
2072.endd
2073must be defined in &_Local/Makefile_&. Details of this facility are given in
2074chapter &<<CHAPperl>>&.
168e428f 2075
f89d2485 2076.cindex "X11 libraries, location of"
168e428f 2077The location of the X11 libraries is something that varies a lot between
068aaea8 2078operating systems, and there may be different versions of X11 to cope
168e428f
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2079with. Exim itself makes no use of X11, but if you are compiling the Exim
2080monitor, the X11 libraries must be available.
9b371988
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2081The following three variables are set in &_OS/Makefile-Default_&:
2082.code
2083X11=/usr/X11R6
2084XINCLUDE=-I$(X11)/include
2085XLFLAGS=-L$(X11)/lib
2086.endd
168e428f 2087These are overridden in some of the operating-system configuration files. For
9b371988
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2088example, in &_OS/Makefile-SunOS5_& there is
2089.code
2090X11=/usr/openwin
2091XINCLUDE=-I$(X11)/include
2092XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2093.endd
168e428f
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2094If you need to override the default setting for your operating system, place a
2095definition of all three of these variables into your
9b371988 2096&_Local/Makefile-<ostype>_& file.
168e428f 2097
9b371988 2098.cindex "EXTRALIBS"
168e428f
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2099If you need to add any extra libraries to the link steps, these can be put in a
2100variable called EXTRALIBS, which appears in all the link commands, but by
2101default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2102command for linking the main Exim binary, and not for any associated utilities.
2103
9b371988 2104.cindex "DBM libraries" "configuration for building"
168e428f 2105There is also DBMLIB, which appears in the link commands for binaries that
9b371988 2106use DBM functions (see also section &<<SECTdb>>&). Finally, there is
168e428f
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2107EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2108binary, and which can be used, for example, to include additional X11
2109libraries.
2110
9b371988 2111.cindex "configuration file" "editing"
168e428f
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2112The make file copes with rebuilding Exim correctly if any of the configuration
2113files are edited. However, if an optional configuration file is deleted, it is
9b371988
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2114necessary to touch the associated non-optional file (that is,
2115&_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
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2116
2117
f89d2485 2118.section "OS-specific header files" "SECID30"
9b371988
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2119.cindex "&_os.h_&"
2120.cindex "building Exim" "OS-specific C header files"
2121The &_OS_& directory contains a number of files with names of the form
2122&_os.h-<ostype>_&. These are system-specific C header files that should not
168e428f 2123normally need to be changed. There is a list of macro settings that are
9b371988 2124recognized in the file &_OS/os.configuring_&, which should be consulted if you
168e428f
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2125are porting Exim to a new operating system.
2126
2127
2128
f89d2485
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2129.section "Overriding build-time options for the monitor" "SECID31"
2130.cindex "building Eximon"
168e428f
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2131A similar process is used for overriding things when building the Exim monitor,
2132where the files that are involved are
9b371988
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2133.display
2134&_OS/eximon.conf-Default_&
2135&_OS/eximon.conf-_&<&'ostype'&>
2136&_Local/eximon.conf_&
2137&_Local/eximon.conf-_&<&'ostype'&>
2138&_Local/eximon.conf-_&<&'archtype'&>
2139&_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2140.endd
2141.cindex "&_Local/eximon.conf_&"
168e428f 2142As with Exim itself, the final three files need not exist, and in this case the
9b371988
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2143&_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2144&_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
168e428f
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2145variables of the same name, preceded by EXIMON_. For example, setting
2146EXIMON_LOG_DEPTH in the environment overrides the value of
2147LOG_DEPTH at run time.
4f578862 2148.ecindex IIDbuex
168e428f
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2149
2150
f89d2485 2151.section "Installing Exim binaries and scripts" "SECID32"
9b371988
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2152.cindex "installing Exim"
2153.cindex "BIN_DIRECTORY"
2154The command &`make install`& runs the &(exim_install)& script with no
2155arguments. The script copies binaries and utility scripts into the directory
2156whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2157.cindex "setuid" "installing Exim with"
068aaea8
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2158The install script copies files only if they are newer than the files they are
2159going to replace. The Exim binary is required to be owned by root and have the
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2160&'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2161install`& as root so that it can set up the Exim binary in this way. However, in
068aaea8
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2162some special situations (for example, if a host is doing no local deliveries)
2163it may be possible to run Exim without making the binary setuid root (see
9b371988 2164chapter &<<CHAPsecurity>>& for details).
168e428f 2165
9b371988 2166.cindex "CONFIGURE_FILE"
168e428f 2167Exim's run time configuration file is named by the CONFIGURE_FILE setting
9b371988
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2168in &_Local/Makefile_&. If this names a single file, and the file does not
2169exist, the default configuration file &_src/configure.default_& is copied there
168e428f
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2170by the installation script. If a run time configuration file already exists, it
2171is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2172alternative files, no default is installed.
2173
9b371988
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2174.cindex "system aliases file"
2175.cindex "&_/etc/aliases_&"
168e428f
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2176One change is made to the default configuration file when it is installed: the
2177default configuration contains a router that references a system aliases file.
2178The path to this file is set to the value specified by
9b371988 2179SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
168e428f
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2180If the system aliases file does not exist, the installation script creates it,
2181and outputs a comment to the user.
2182
2183The created file contains no aliases, but it does contain comments about the
2184aliases a site should normally have. Mail aliases have traditionally been
9b371988
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2185kept in &_/etc/aliases_&. However, some operating systems are now using
2186&_/etc/mail/aliases_&. You should check if yours is one of these, and change
168e428f
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2187Exim's configuration if necessary.
2188
2189The default configuration uses the local host's name as the only local domain,
9b371988
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2190and is set up to do local deliveries into the shared directory &_/var/mail_&,
2191running as the local user. System aliases and &_.forward_& files in users' home
168e428f
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2192directories are supported, but no NIS or NIS+ support is configured. Domains
2193other than the name of the local host are routed using the DNS, with delivery
2194over SMTP.
2195
168e428f
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2196It is possible to install Exim for special purposes (such as building a binary
2197distribution) in a private part of the file system. You can do this by a
2198command such as
9b371988
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2199.code
2200make DESTDIR=/some/directory/ install
2201.endd
168e428f
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2202This has the effect of pre-pending the specified directory to all the file
2203paths, except the name of the system aliases file that appears in the default
9b371988 2204configuration. (If a default alias file is created, its name &'is'& modified.)
168e428f
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2205For backwards compatibility, ROOT is used if DESTDIR is not set,
2206but this usage is deprecated.
2207
9b371988
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2208.cindex "installing Exim" "what is not installed"
2209Running &'make install'& does not copy the Exim 4 conversion script
2210&'convert4r4'&, or the &'pcretest'& test program. You will probably run the
168e428f 2211first of these only once (if you are upgrading from Exim 3), and the second
9b371988 2212isn't really part of Exim. None of the documentation files in the &_doc_&
168e428f 2213directory are copied, except for the info files when you have set
9b371988 2214INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
168e428f 2215
9b371988 2216For the utility programs, old versions are renamed by adding the suffix &_.O_&
168e428f
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2217to their names. The Exim binary itself, however, is handled differently. It is
2218installed under a name that includes the version number and the compile number,
9b371988
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2219for example &_exim-&version;-1_&. The script then arranges for a symbolic link
2220called &_exim_& to point to the binary. If you are updating a previous version
2221of Exim, the script takes care to ensure that the name &_exim_& is never absent
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2222from the directory (as seen by other processes).
2223
9b371988
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2224.cindex "installing Exim" "testing the script"
2225If you want to see what the &'make install'& will do before running it for
2226real, you can pass the &%-n%& option to the installation script by this
2227command:
2228.code
2229make INSTALL_ARG=-n install
2230.endd
168e428f
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2231The contents of the variable INSTALL_ARG are passed to the installation
2232script. You do not need to be root to run this test. Alternatively, you can run
2233the installation script directly, but this must be from within the build
2234directory. For example, from the top-level Exim directory you could use this
2235command:
9b371988
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2236.code
2237(cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2238.endd
2239.cindex "installing Exim" "install script options"
168e428f
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2240There are two other options that can be supplied to the installation script.
2241
9b371988
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2242.ilist
2243&%-no_chown%& bypasses the call to change the owner of the installed binary
168e428f 2244to root, and the call to make it a setuid binary.
9b371988
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2245.next
2246&%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
168e428f 2247installed binary.
9b371988 2248.endlist
168e428f
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2249
2250INSTALL_ARG can be used to pass these options to the script. For example:
9b371988
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2251.code
2252make INSTALL_ARG=-no_symlink install
2253.endd
168e428f
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2254The installation script can also be given arguments specifying which files are
2255to be copied. For example, to install just the Exim binary, and nothing else,
2256without creating the symbolic link, you could use:
9b371988
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2257.code
2258make INSTALL_ARG='-no_symlink exim' install
2259.endd
168e428f
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2260
2261
2262
9b371988
PH
2263.section "Installing info documentation" "SECTinsinfdoc"
2264.cindex "installing Exim" "&'info'& documentation"
2265Not all systems use the GNU &'info'& system for documentation, and for this
168e428f
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2266reason, the Texinfo source of Exim's documentation is not included in the main
2267distribution. Instead it is available separately from the ftp site (see section
9b371988 2268&<<SECTavail>>&).
168e428f 2269
9b371988
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2270If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2271source of the documentation is found in the source tree, running &`make
2272install`& automatically builds the info files and installs them.
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2273
2274
2275
f89d2485 2276.section "Setting up the spool directory" "SECID33"
9b371988 2277.cindex "spool directory" "creating"
168e428f
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2278When it starts up, Exim tries to create its spool directory if it does not
2279exist. The Exim uid and gid are used for the owner and group of the spool
2280directory. Sub-directories are automatically created in the spool directory as
2281necessary.
2282
2283
2284
2285
f89d2485 2286.section "Testing" "SECID34"
9b371988 2287.cindex "testing" "installation"
168e428f
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2288Having installed Exim, you can check that the run time configuration file is
2289syntactically valid by running the following command, which assumes that the
2290Exim binary directory is within your PATH environment variable:
9b371988
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2291.code
2292exim -bV
2293.endd
168e428f
PH
2294If there are any errors in the configuration file, Exim outputs error messages.
2295Otherwise it outputs the version number and build date,
2296the DBM library that is being used, and information about which drivers and
2297other optional code modules are included in the binary.
2298Some simple routing tests can be done by using the address testing option. For
2299example,
9b371988
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2300.display
2301&`exim -bt`& <&'local username'&>
2302.endd
168e428f 2303should verify that it recognizes a local mailbox, and
9b371988
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2304.display
2305&`exim -bt`& <&'remote address'&>
2306.endd
168e428f
PH
2307a remote one. Then try getting it to deliver mail, both locally and remotely.
2308This can be done by passing messages directly to Exim, without going through a
2309user agent. For example:
9b371988 2310.code
068aaea8
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2311exim -v postmaster@your.domain.example
2312From: user@your.domain.example
2313To: postmaster@your.domain.example
2314Subject: Testing Exim
168e428f 2315
068aaea8
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2316This is a test message.
2317^D
9b371988
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2318.endd
2319The &%-v%& option causes Exim to output some verification of what it is doing.
168e428f 2320In this case you should see copies of three log lines, one for the message's
9b371988 2321arrival, one for its delivery, and one containing &"Completed"&.
168e428f 2322
9b371988
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2323.cindex "delivery" "problems with"
2324If you encounter problems, look at Exim's log files (&'mainlog'& and
2325&'paniclog'&) to see if there is any relevant information there. Another source
168e428f 2326of information is running Exim with debugging turned on, by specifying the
9b371988 2327&%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
168e428f 2328with debugging turned on by a command of the form
9b371988
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2329.display
2330&`exim -d -M`& <&'exim-message-id'&>
2331.endd
2332You must be root or an &"admin user"& in order to do this. The &%-d%& option
168e428f 2333produces rather a lot of output, but you can cut this down to specific areas.
9b371988
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2334For example, if you use &%-d-all+route%& only the debugging information
2335relevant to routing is included. (See the &%-d%& option in chapter
2336&<<CHAPcommandline>>& for more details.)
168e428f 2337
9b371988
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2338.cindex '&"sticky"& bit'
2339.cindex "lock files"
168e428f
PH
2340One specific problem that has shown up on some sites is the inability to do
2341local deliveries into a shared mailbox directory, because it does not have the
9b371988 2342&"sticky bit"& set on it. By default, Exim tries to create a lock file before
168e428f 2343writing to a mailbox file, and if it cannot create the lock file, the delivery
9b371988 2344is deferred. You can get round this either by setting the &"sticky bit"& on the
168e428f
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2345directory, or by setting a specific group for local deliveries and allowing
2346that group to create files in the directory (see the comments above the
9b371988 2347&(local_delivery)& transport in the default configuration file). Another
168e428f 2348approach is to configure Exim not to use lock files, but just to rely on
9b371988
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2349&[fcntl()]& locking instead. However, you should do this only if all user
2350agents also use &[fcntl()]& locking. For further discussion of locking issues,
2351see chapter &<<CHAPappendfile>>&.
168e428f
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2352
2353One thing that cannot be tested on a system that is already running an MTA is
2354the receipt of incoming SMTP mail on the standard SMTP port. However, the
9b371988
PH
2355&%-oX%& option can be used to run an Exim daemon that listens on some other
2356port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2357&'exim_checkaccess'& utility can be used to check out policy controls on
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2358incoming SMTP mail.
2359
2360Testing a new version on a system that is already running Exim can most easily
2361be done by building a binary with a different CONFIGURE_FILE setting. From
2362within the run time configuration, all other file and directory names
2363that Exim uses can be altered, in order to keep it entirely clear of the
2364production version.
2365
2366
f89d2485 2367.section "Replacing another MTA with Exim" "SECID35"
9b371988 2368.cindex "replacing another MTA"
168e428f
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2369Building and installing Exim for the first time does not of itself put it in
2370general use. The name by which the system's MTA is called by mail user agents
9b371988
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2371is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2372operating system), and it is necessary to make this name point to the &'exim'&
168e428f 2373binary in order to get the user agents to pass messages to Exim. This is
9b371988
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2374normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2375or &_/usr/lib/sendmail_&
2376.cindex "symbolic link" "to &'exim'& binary"
2377a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
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2378privilege and executable status from the old MTA. It is then necessary to stop
2379and restart the mailer daemon, if one is running.
2380
f89d2485 2381.cindex "FreeBSD, MTA indirection"
9b371988 2382.cindex "&_/etc/mail/mailer.conf_&"
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2383Some operating systems have introduced alternative ways of switching MTAs. For
2384example, if you are running FreeBSD, you need to edit the file
9b371988 2385&_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
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2386described. A typical example of the contents of this file for running Exim is
2387as follows:
9b371988
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2388.code
2389sendmail /usr/exim/bin/exim
2390send-mail /usr/exim/bin/exim
2391mailq /usr/exim/bin/exim -bp
2392newaliases /usr/bin/true
2393.endd
2394Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2395your Exim installation is &"live"&. Check it by sending a message from your
168e428f
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2396favourite user agent.
2397
2398You should consider what to tell your users about the change of MTA. Exim may
2399have different capabilities to what was previously running, and there are
2400various operational differences such as the text of messages produced by
2401command line options and in bounce messages. If you allow your users to make
2402use of Exim's filtering capabilities, you should make the document entitled
9b371988 2403&'Exim's interface to mail filtering'& available to them.
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2404
2405
2406
f89d2485 2407.section "Upgrading Exim" "SECID36"
9b371988 2408.cindex "upgrading Exim"
168e428f
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2409If you are already running Exim on your host, building and installing a new
2410version automatically makes it available to MUAs, or any other programs that
2411call the MTA directly. However, if you are running an Exim daemon, you do need
9b371988
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2412to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2413new binary. You do not need to stop processing mail in order to install a new
068aaea8
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2414version of Exim. The install script does not modify an existing runtime
2415configuration file.
2416
168e428f
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2417
2418
2419
f89d2485 2420.section "Stopping the Exim daemon on Solaris" "SECID37"
9b371988 2421.cindex "Solaris" "stopping Exim on"
168e428f 2422The standard command for stopping the mailer daemon on Solaris is
9b371988
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2423.code
2424/etc/init.d/sendmail stop
2425.endd
2426If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2427fails to stop Exim because it uses the command &'ps -e'& and greps the output
2428for the text &"sendmail"&; this is not present because the actual program name
2429(that is, &"exim"&) is given by the &'ps'& command with these options. A
2430solution is to replace the line that finds the process id with something like
2431.code
2432pid=`cat /var/spool/exim/exim-daemon.pid`
2433.endd
168e428f
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2434to obtain the daemon's pid directly from the file that Exim saves it in.
2435
9b371988 2436Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
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2437still be received from local processes, and if automatic delivery is configured
2438(the normal case), deliveries will still occur.
2439
2440
2441
2442
9b371988
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2443. ////////////////////////////////////////////////////////////////////////////
2444. ////////////////////////////////////////////////////////////////////////////
168e428f 2445
9b371988 2446.chapter "The Exim command line" "CHAPcommandline"
4f578862
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2447.scindex IIDclo1 "command line" "options"
2448.scindex IIDclo2 "options" "command line"
168e428f
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2449Exim's command line takes the standard Unix form of a sequence of options,
2450each starting with a hyphen character, followed by a number of arguments. The
2451options are compatible with the main options of Sendmail, and there are also
2452some additional options, some of which are compatible with Smail 3. Certain
2453combinations of options do not make sense, and provoke an error if used.
2454The form of the arguments depends on which options are set.
2455
2456
f89d2485 2457.section "Setting options by program name" "SECID38"
9b371988
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2458.cindex "&'mailq'&"
2459If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
168e428f 2460were present before any other options.
9b371988 2461The &%-bp%& option requests a listing of the contents of the mail queue on the
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2462standard output.
2463This feature is for compatibility with some systems that contain a command of
2464that name in one of the standard libraries, symbolically linked to
9b371988
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2465&_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2466
2467.cindex "&'rsmtp'&"
2468If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2469were present before any other options, for compatibility with Smail. The
2470&%-bS%& option is used for reading in a number of messages in batched SMTP
2471format.
2472
2473.cindex "&'rmail'&"
2474If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2475&%-oee%& options were present before any other options, for compatibility with
2476Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2477
2478.cindex "&'runq'&"
2479.cindex "queue runner"
2480If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2481were present before any other options, for compatibility with Smail. The &%-q%&
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2482option causes a single queue runner process to be started.
2483
9b371988
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2484.cindex "&'newaliases'&"
2485.cindex "alias file" "building"
2486.cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2487If Exim is called under the name &'newaliases'& it behaves as if the option
2488&%-bi%& were present before any other options, for compatibility with Sendmail.
168e428f
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2489This option is used for rebuilding Sendmail's alias file. Exim does not have
2490the concept of a single alias file, but can be configured to run a given
9b371988 2491command if called with the &%-bi%& option.
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2492
2493
9b371988
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2494.section "Trusted and admin users" "SECTtrustedadmin"
2495Some Exim options are available only to &'trusted users'& and others are
2496available only to &'admin users'&. In the description below, the phrases &"Exim
2497user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2498EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2499&%exim_group%& options. These do not necessarily have to use the name &"exim"&.
168e428f 2500
9b371988 2501.ilist
f89d2485 2502.cindex "trusted users" "definition of"
9b371988 2503.cindex "user" "trusted definition of"
168e428f 2504The trusted users are root, the Exim user, any user listed in the
9b371988
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2505&%trusted_users%& configuration option, and any user whose current group or any
2506supplementary group is one of those listed in the &%trusted_groups%&
168e428f 2507configuration option. Note that the Exim group is not automatically trusted.
9b371988
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2508
2509.cindex '&"From"& line'
2510.cindex "envelope sender"
2511Trusted users are always permitted to use the &%-f%& option or a leading
2512&"From&~"& line to specify the envelope sender of a message that is passed to
2513Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2514See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2515users to set envelope senders.
2516
2517.cindex "&'From:'& header line"
2518.cindex "&'Sender:'& header line"
2519For a trusted user, there is never any check on the contents of the &'From:'&
2520header line, and a &'Sender:'& line is never added. Furthermore, any existing
2521&'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2522
168e428f
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2523Trusted users may also specify a host name, host address, interface address,
2524protocol name, ident value, and authentication data when submitting a message
2525locally. Thus, they are able to insert messages into Exim's queue locally that
2526have the characteristics of messages received from a remote host. Untrusted
9b371988 2527users may in some circumstances use &%-f%&, but can never set the other values
168e428f 2528that are available to trusted users.
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2529.next
2530.cindex "user" "admin definition of"
2531.cindex "admin user" "definition of"
168e428f 2532The admin users are root, the Exim user, and any user that is a member of the
9b371988 2533Exim group or of any group listed in the &%admin_groups%& configuration option.
168e428f 2534The current group does not have to be one of these groups.
9b371988 2535
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2536Admin users are permitted to list the queue, and to carry out certain
2537operations on messages, for example, to force delivery failures. It is also
2538necessary to be an admin user in order to see the full information provided by
2539the Exim monitor, and full debugging output.
9b371988
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2540
2541By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2542Exim to attempt delivery of messages on its queue is restricted to admin users.
2543However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2544option false (that is, specifying &%no_prod_requires_admin%&).
2545
2546Similarly, the use of the &%-bp%& option to list all the messages in the queue
2547is restricted to admin users unless &%queue_list_requires_admin%& is set
168e428f 2548false.
9b371988 2549.endlist
168e428f
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2550
2551
9b371988 2552&*Warning*&: If you configure your system so that admin users are able to
168e428f
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2553edit Exim's configuration file, you are giving those users an easy way of
2554getting root. There is further discussion of this issue at the start of chapter
9b371988 2555&<<CHAPconf>>&.
168e428f
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2556
2557
2558
2559
f89d2485 2560.section "Command line options" "SECID39"
db9452a9
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2561Exim's command line options are described in alphabetical order below. If none
2562of the options that specifies a specific action (such as starting the daemon or
2563a queue runner, or testing an address, or receiving a message in a specific
2564format, or listing the queue) are present, and there is at least one argument
2565on the command line, &%-bm%& (accept a local message on the standard input,
2566with the arguments specifying the recipients) is assumed. Otherwise, Exim
2567outputs a brief message about itself and exits.
168e428f 2568
9b371988
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2569. ////////////////////////////////////////////////////////////////////////////
2570. Insert a stylized XML comment here, to identify the start of the command line
2571. options. This is for the benefit of the Perl script that automatically
2572. creates a man page for the options.
2573. ////////////////////////////////////////////////////////////////////////////
168e428f 2574
9b371988 2575.literal xml
168e428f 2576<!-- === Start of command line options === -->
9b371988 2577.literal off
168e428f
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2578
2579
9b371988
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2580.vlist
2581.vitem &%--%&
2582.oindex "--"
2583.cindex "options" "command line; terminating"
168e428f
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2584This is a pseudo-option whose only purpose is to terminate the options and
2585therefore to cause subsequent command line items to be treated as arguments
2586rather than options, even if they begin with hyphens.
2587
9b371988
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2588.vitem &%--help%&
2589.oindex "&%--help%&"
168e428f
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2590This option causes Exim to output a few sentences stating what it is.
2591The same output is generated if the Exim binary is called with no options and
2592no arguments.
2593
9b371988
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2594.vitem &%-B%&<&'type'&>
2595.oindex "&%-B%&"
2596.cindex "8-bit characters"
2597.cindex "Sendmail compatibility" "8-bit characters"
168e428f
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2598This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2599clean; it ignores this option.
2600
9b371988
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2601.vitem &%-bd%&
2602.oindex "&%-bd%&"
2603.cindex "daemon"
f89d2485 2604.cindex "SMTP" "listener"
9b371988 2605.cindex "queue runner"
168e428f 2606This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
9b371988
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2607the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2608that the daemon should also initiate periodic queue runs.
2609
2610The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2611(debugging) or &%-v%& (verifying) options are set, the daemon does not
168e428f
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2612disconnect from the controlling terminal. When running this way, it can be
2613stopped by pressing ctrl-C.
9b371988 2614
168e428f
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2615By default, Exim listens for incoming connections to the standard SMTP port on
2616all the host's running interfaces. However, it is possible to listen on other
2617ports, on multiple ports, and only on specific interfaces. Chapter
9b371988
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2618&<<CHAPinterfaces>>& contains a description of the options that control this.
2619
168e428f 2620When a listening daemon
9b371988
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2621.cindex "daemon" "process id (pid)"
2622.cindex "pid (process id)" "of daemon"
2623is started without the use of &%-oX%& (that is, without overriding the normal
2624configuration), it writes its process id to a file called &_exim-daemon.pid_&
2625in Exim's spool directory. This location can be overridden by setting
2626PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
168e428f 2627running as root.
9b371988
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2628
2629When &%-oX%& is used on the command line to start a listening daemon, the
2630process id is not written to the normal pid file path. However, &%-oP%& can be
168e428f 2631used to specify a path on the command line if a pid file is required.
9b371988 2632
168e428f 2633The SIGHUP signal
9b371988 2634.cindex "SIGHUP"
3cb1b51e
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2635.cindex "daemon" "restarting"
2636can be used to cause the daemon to re-execute itself. This should be done
2637whenever Exim's configuration file, or any file that is incorporated into it by
2638means of the &%.include%& facility, is changed, and also whenever a new version
2639of Exim is installed. It is not necessary to do this when other files that are
9b371988
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2640referenced from the configuration (for example, alias files) are changed,
2641because these are reread each time they are used.
2642
2643.vitem &%-bdf%&
2644.oindex "&%-bdf%&"
2645This option has the same effect as &%-bd%& except that it never disconnects
2646from the controlling terminal, even when no debugging is specified.
2647
2648.vitem &%-be%&
2649.oindex "&%-be%&"
2650.cindex "testing" "string expansion"
2651.cindex "expansion" "testing"
168e428f
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2652Run Exim in expansion testing mode. Exim discards its root privilege, to
2653prevent ordinary users from using this mode to read otherwise inaccessible
2654files. If no arguments are given, Exim runs interactively, prompting for lines
4f578862 2655of data. Otherwise, it processes each argument in turn.
9b371988
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2656
2657If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2658to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2659used without command line arguments. If successful, it uses the &[readline()]&
168e428f
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2660function, which provides extensive line-editing facilities, for reading the
2661test data. A line history is supported.
9b371988 2662
168e428f 2663Long expansion expressions can be split over several lines by using backslash
068aaea8 2664continuations. As in Exim's run time configuration, white space at the start of
168e428f
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2665continuation lines is ignored. Each argument or data line is passed through the
2666string expansion mechanism, and the result is output. Variable values from the
9b371988 2667configuration file (for example, &$qualify_domain$&) are available, but no
3cb1b51e 2668message-specific values (such as &$sender_domain$&) are set, because no message
f89d2485 2669is being processed (but see &%-bem%& and &%-Mset%&).
168e428f 2670
9b371988
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2671&*Note*&: If you use this mechanism to test lookups, and you change the data
2672files or databases you are using, you must exit and restart Exim before trying
2673the same lookup again. Otherwise, because each Exim process caches the results
2674of lookups, you will just get the same result as before.
9b371988 2675
3cb1b51e
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2676.vitem &%-bem%&&~<&'filename'&>
2677.oindex "&%-bem%&"
2678.cindex "testing" "string expansion"
2679.cindex "expansion" "testing"
2680This option operates like &%-be%& except that it must be followed by the name
2681of a file. For example:
2682.code
2683exim -bem /tmp/testmessage
2684.endd
2685The file is read as a message (as if receiving a locally-submitted non-SMTP
2686message) before any of the test expansions are done. Thus, message-specific
2687variables such as &$message_size$& and &$header_from:$& are available. However,
2688no &'Received:'& header is added to the message. If the &%-t%& option is set,
2689recipients are read from the headers in the normal way, and are shown in the
2690&$recipients$& variable. Note that recipients cannot be given on the command
2691line, because further arguments are taken as strings to expand (just like
2692&%-be%&).
3cb1b51e 2693
9b371988
PH
2694.vitem &%-bF%&&~<&'filename'&>
2695.oindex "&%-bF%&"
2696.cindex "system filter" "testing"
2697.cindex "testing" "system filter"
2698This option is the same as &%-bf%& except that it assumes that the filter being
168e428f
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2699tested is a system filter. The additional commands that are available only in
2700system filters are recognized.
2701
9b371988
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2702.vitem &%-bf%&&~<&'filename'&>
2703.oindex "&%-bf%&"
2704.cindex "filter" "testing"
2705.cindex "testing" "filter file"
2706.cindex "forward file" "testing"
2707.cindex "testing" "forward file"
2708.cindex "Sieve filter" "testing"
168e428f
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2709This option runs Exim in user filter testing mode; the file is the filter file
2710to be tested, and a test message must be supplied on the standard input. If
2711there are no message-dependent tests in the filter, an empty file can be
2712supplied.
168e428f 2713
9b371988
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2714If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2715can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2716filter and a user filter in the same run. For example:
2717.code
2718exim -bF /system/filter -bf /user/filter </test/message
2719.endd
168e428f
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2720This is helpful when the system filter adds header lines or sets filter
2721variables that are used by the user filter.
168e428f 2722
9b371988
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2723If the test filter file does not begin with one of the special lines
2724.code
2725# Exim filter
2726# Sieve filter
2727.endd
2728it is taken to be a normal &_.forward_& file, and is tested for validity under
2729that interpretation. See sections &<<SECTitenonfilred>>& to
2730&<<SECTspecitredli>>& for a description of the possible contents of non-filter
2731redirection lists.
2732
2733The result of an Exim command that uses &%-bf%&, provided no errors are
168e428f
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2734detected, is a list of the actions that Exim would try to take if presented
2735with the message for real. More details of filter testing are given in the
9b371988
PH
2736separate document entitled &'Exim's interfaces to mail filtering'&.
2737
168e428f 2738When testing a filter file,
9b371988
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2739.cindex "&""From""& line"
2740.cindex "envelope sender"
f89d2485 2741.oindex "&%-f%&" "for filter testing"
9b371988
PH
2742the envelope sender can be set by the &%-f%& option,
2743or by a &"From&~"& line at the start of the test message. Various parameters
2744that would normally be taken from the envelope recipient address of the message
2745can be set by means of additional command line options (see the next four
2746options).
2747
2748.vitem &%-bfd%&&~<&'domain'&>
2749.oindex "&%-bfd%&"
f89d2485 2750.vindex "&$qualify_domain$&"
168e428f 2751This sets the domain of the recipient address when a filter file is being
9b371988
PH
2752tested by means of the &%-bf%& option. The default is the value of
2753&$qualify_domain$&.
168e428f 2754
9b371988
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2755.vitem &%-bfl%&&~<&'local&~part'&>
2756.oindex "&%-bfl%&"
168e428f 2757This sets the local part of the recipient address when a filter file is being
9b371988 2758tested by means of the &%-bf%& option. The default is the username of the
168e428f
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2759process that calls Exim. A local part should be specified with any prefix or
2760suffix stripped, because that is how it appears to the filter when a message is
2761actually being delivered.
2762
9b371988
PH
2763.vitem &%-bfp%&&~<&'prefix'&>
2764.oindex "&%-bfp%&"
168e428f 2765This sets the prefix of the local part of the recipient address when a filter
9b371988 2766file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
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2767prefix.
2768
9b371988
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2769.vitem &%-bfs%&&~<&'suffix'&>
2770.oindex "&%-bfs%&"
168e428f 2771This sets the suffix of the local part of the recipient address when a filter
9b371988 2772file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
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2773suffix.
2774
9b371988
PH
2775.vitem &%-bh%&&~<&'IP&~address'&>
2776.oindex "&%-bh%&"
2777.cindex "testing" "incoming SMTP"
2778.cindex "SMTP" "testing incoming"
2779.cindex "testing" "relay control"
2780.cindex "relaying" "testing configuration"
2781.cindex "policy control" "testing"
2782.cindex "debugging" "&%-bh%& option"
168e428f
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2783This option runs a fake SMTP session as if from the given IP address, using the
2784standard input and output. The IP address may include a port number at the end,
2785after a full stop. For example:
9b371988
PH
2786.code
2787exim -bh 10.9.8.7.1234
2788exim -bh fe80::a00:20ff:fe86:a061.5678
2789.endd
168e428f 2790When an IPv6 address is given, it is converted into canonical form. In the case
9b371988
PH
2791of the second example above, the value of &$sender_host_address$& after
2792conversion to the canonical form is
2793&`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2794
168e428f 2795Comments as to what is going on are written to the standard error file. These
9b371988 2796include lines beginning with &"LOG"& for anything that would have been logged.
168e428f
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2797This facility is provided for testing configuration options for incoming
2798messages, to make sure they implement the required policy. For example, you can
9b371988
PH
2799test your relay controls using &%-bh%&.
2800
2801&*Warning 1*&:
2802.cindex "RFC 1413"
db9452a9
PH
2803You can test features of the configuration that rely on ident (RFC 1413)
2804information by using the &%-oMt%& option. However, Exim cannot actually perform
2805an ident callout when testing using &%-bh%& because there is no incoming SMTP
2806connection.
9b371988
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2807
2808&*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2809are also skipped when testing using &%-bh%&. If you want these callouts to
2810occur, use &%-bhc%& instead.
2811
168e428f
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2812Messages supplied during the testing session are discarded, and nothing is
2813written to any of the real log files. There may be pauses when DNS (and other)
9b371988 2814lookups are taking place, and of course these may time out. The &%-oMi%& option
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2815can be used to specify a specific IP interface and port if this is important,
2816and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2817session were authenticated.
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2818
2819The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
168e428f 2820output just states whether a given recipient address from a given host is
9b371988 2821acceptable or not. See section &<<SECTcheckaccess>>&.
168e428f 2822
3cb1b51e
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2823.new
2824Features such as authentication and encryption, where the client input is not
f89d2485
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2825plain text, cannot easily be tested with &%-bh%&. Instead, you should use a
2826specialized SMTP test program such as
3cb1b51e
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2827&url(http://jetmore.org/john/code/#swaks,swaks).
2828.wen
2829
9b371988
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2830.vitem &%-bhc%&&~<&'IP&~address'&>
2831.oindex "&%-bhc%&"
2832This option operates in the same way as &%-bh%&, except that address
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2833verification callouts are performed if required. This includes consulting and
2834updating the callout cache database.
2835
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2836.vitem &%-bi%&
2837.oindex "&%-bi%&"
2838.cindex "alias file" "building"
2839.cindex "building alias file"
2840.cindex "Sendmail compatibility" "&%-bi%& option"
2841Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
168e428f 2842Exim does not have the concept of a single alias file, and so it cannot mimic
9b371988 2843this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
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2844tend to appear in various scripts such as NIS make files, so the option must be
2845recognized.
9b371988
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2846
2847If &%-bi%& is encountered, the command specified by the &%bi_command%&
168e428f 2848configuration option is run, under the uid and gid of the caller of Exim. If
9b371988
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2849the &%-oA%& option is used, its value is passed to the command as an argument.
2850The command set by &%bi_command%& may not contain arguments. The command can
2851use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2852if this is required. If the &%bi_command%& option is not set, calling Exim with
2853&%-bi%& is a no-op.
2854
2855.vitem &%-bm%&
2856.oindex "&%-bm%&"
2857.cindex "local message reception"
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2858This option runs an Exim receiving process that accepts an incoming,
2859locally-generated message on the current input. The recipients are given as the
9b371988 2860command arguments (except when &%-t%& is also present &-- see below). Each
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2861argument can be a comma-separated list of RFC 2822 addresses. This is the
2862default option for selecting the overall action of an Exim call; it is assumed
2863if no other conflicting option is present.
9b371988 2864
168e428f 2865If any addresses in the message are unqualified (have no domain), they are
9b371988
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2866qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
2867options, as appropriate. The &%-bnq%& option (see below) provides a way of
168e428f 2868suppressing this for special cases.
9b371988 2869
168e428f 2870Policy checks on the contents of local messages can be enforced by means of
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2871the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
2872
2873.cindex "return code" "for &%-bm%&"
2874The return code is zero if the message is successfully accepted. Otherwise, the
2875action is controlled by the &%-oe%&&'x'& option setting &-- see below.
2876
168e428f 2877The format
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2878.cindex "message" "format"
2879.cindex "format" "message"
2880.cindex "&""From""& line"
2881.cindex "UUCP" "&""From""& line"
2882.cindex "Sendmail compatibility" "&""From""& line"
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2883of the message must be as defined in RFC 2822, except that, for
2884compatibility with Sendmail and Smail, a line in one of the forms
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2885.code
2886From sender Fri Jan 5 12:55 GMT 1997
2887From sender Fri, 5 Jan 97 12:55:01
2888.endd
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2889(with the weekday optional, and possibly with additional text after the date)
2890is permitted to appear at the start of the message. There appears to be no
2891authoritative specification of the format of this line. Exim recognizes it by
9b371988 2892matching against the regular expression defined by the &%uucp_from_pattern%&
168e428f 2893option, which can be changed if necessary.
9b371988 2894
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2895.oindex "&%-f%&" "overriding &""From""& line"
2896The specified sender is treated as if it were given as the argument to the
9b371988 2897&%-f%& option, but if a &%-f%& option is also present, its argument is used in
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2898preference to the address taken from the message. The caller of Exim must be a
2899trusted user for the sender of a message to be set in this way.
2900
9b371988
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2901.vitem &%-bnq%&
2902.oindex "&%-bnq%&"
f89d2485 2903.cindex "address qualification, suppressing"
168e428f
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2904By default, Exim automatically qualifies unqualified addresses (those
2905without domains) that appear in messages that are submitted locally (that
2906is, not over TCP/IP). This qualification applies both to addresses in
2907envelopes, and addresses in header lines. Sender addresses are qualified using
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2908&%qualify_domain%&, and recipient addresses using &%qualify_recipient%& (which
2909defaults to the value of &%qualify_domain%&).
2910
2911Sometimes, qualification is not wanted. For example, if &%-bS%& (batch SMTP) is
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2912being used to re-submit messages that originally came from remote hosts after
2913content scanning, you probably do not want to qualify unqualified addresses in
2914header lines. (Such lines will be present only if you have not enabled a header
2915syntax check in the appropriate ACL.)
9b371988
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2916
2917The &%-bnq%& option suppresses all qualification of unqualified addresses in
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2918messages that originate on the local host. When this is used, unqualified
2919addresses in the envelope provoke errors (causing message rejection) and
2920unqualified addresses in header lines are left alone.
2921
2922
9b371988
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2923.vitem &%-bP%&
2924.oindex "&%-bP%&"
f89d2485 2925.cindex "configuration options, extracting"
9b371988 2926.cindex "options" "configuration &-- extracting"
168e428f
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2927If this option is given with no arguments, it causes the values of all Exim's
2928main configuration options to be written to the standard output. The values
2929of one or more specific options can be requested by giving their names as
2930arguments, for example:
9b371988
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2931.code
2932exim -bP qualify_domain hold_domains
2933.endd
2934However, any option setting that is preceded by the word &"hide"& in the
168e428f
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2935configuration file is not shown in full, except to an admin user. For other
2936users, the output is as in this example:
9b371988
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2937.code
2938mysql_servers = <value not displayable>
2939.endd
2940If &%configure_file%& is given as an argument, the name of the run time
168e428f
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2941configuration file is output.
2942If a list of configuration files was supplied, the value that is output here
2943is the name of the file that was actually used.
168e428f 2944
9b371988
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2945.cindex "daemon" "process id (pid)"
2946.cindex "pid (process id)" "of daemon"
2947If &%log_file_path%& or &%pid_file_path%& are given, the names of the
2948directories where log files and daemon pid files are written are output,
2949respectively. If these values are unset, log files are written in a
2950sub-directory of the spool directory called &%log%&, and the pid file is
2951written directly into the spool directory.
2952
2953If &%-bP%& is followed by a name preceded by &`+`&, for example,
2954.code
2955exim -bP +local_domains
2956.endd
168e428f
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2957it searches for a matching named list of any type (domain, host, address, or
2958local part) and outputs what it finds.
9b371988
PH
2959
2960.cindex "options" "router &-- extracting"
2961.cindex "options" "transport &-- extracting"
2962If one of the words &%router%&, &%transport%&, or &%authenticator%& is given,
168e428f
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2963followed by the name of an appropriate driver instance, the option settings for
2964that driver are output. For example:
9b371988
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2965.code
2966exim -bP transport local_delivery
2967.endd
168e428f
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2968The generic driver options are output first, followed by the driver's private
2969options. A list of the names of drivers of a particular type can be obtained by
9b371988
PH
2970using one of the words &%router_list%&, &%transport_list%&, or
2971&%authenticator_list%&, and a complete list of all drivers with their option
2972settings can be obtained by using &%routers%&, &%transports%&, or
2973&%authenticators%&.
168e428f
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2974
2975
9b371988
PH
2976.vitem &%-bp%&
2977.oindex "&%-bp%&"
2978.cindex "queue" "listing messages on"
2979.cindex "listing" "messages on the queue"
168e428f 2980This option requests a listing of the contents of the mail queue on the
9b371988 2981standard output. If the &%-bp%& option is followed by a list of message ids,
168e428f 2982just those messages are listed. By default, this option can be used only by an
9b371988 2983admin user. However, the &%queue_list_requires_admin%& option can be set false
168e428f 2984to allow any user to see the queue.
168e428f 2985
9b371988
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2986Each message on the queue is displayed as in the following example:
2987.code
298825m 2.9K 0t5C6f-0000c8-00 <alice@wonderland.fict.example>
2989 red.king@looking-glass.fict.example
2990 <other addresses>
2991.endd
2992.cindex "message" "size in queue listing"
2993.cindex "size" "of message"
2994The first line contains the length of time the message has been on the queue
168e428f
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2995(in this case 25 minutes), the size of the message (2.9K), the unique local
2996identifier for the message, and the message sender, as contained in the
2997envelope. For bounce messages, the sender address is empty, and appears as
9b371988 2998&"<>"&. If the message was submitted locally by an untrusted user who overrode
168e428f
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2999the default sender address, the user's login name is shown in parentheses
3000before the sender address.
9b371988
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3001
3002.cindex "frozen messages" "in queue listing"
3003If the message is frozen (attempts to deliver it are suspended) then the text
3004&"*** frozen ***"& is displayed at the end of this line.
3005
168e428f
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3006The recipients of the message (taken from the envelope, not the headers) are
3007displayed on subsequent lines. Those addresses to which the message has already
3008been delivered are marked with the letter D. If an original address gets
3009expanded into several addresses via an alias or forward file, the original is
3010displayed with a D only when deliveries for all of its child addresses are
3011complete.
3012
3013
9b371988
PH
3014.vitem &%-bpa%&
3015.oindex "&%-bpa%&"
3016This option operates like &%-bp%&, but in addition it shows delivered addresses
168e428f 3017that were generated from the original top level address(es) in each message by
9b371988
PH
3018alias or forwarding operations. These addresses are flagged with &"+D"& instead
3019of just &"D"&.
168e428f
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3020
3021
9b371988
PH
3022.vitem &%-bpc%&
3023.oindex "&%-bpc%&"
3024.cindex "queue" "count of messages on"
168e428f
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3025This option counts the number of messages on the queue, and writes the total
3026to the standard output. It is restricted to admin users, unless
9b371988 3027&%queue_list_requires_admin%& is set false.
168e428f
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3028
3029
9b371988
PH
3030.vitem &%-bpr%&
3031.oindex "&%-bpr%&"
3032This option operates like &%-bp%&, but the output is not sorted into
168e428f
PH
3033chronological order of message arrival. This can speed it up when there are
3034lots of messages on the queue, and is particularly useful if the output is
3035going to be post-processed in a way that doesn't need the sorting.
3036
9b371988
PH
3037.vitem &%-bpra%&
3038.oindex "&%-bpra%&"
3039This option is a combination of &%-bpr%& and &%-bpa%&.
168e428f 3040
9b371988
PH
3041.vitem &%-bpru%&
3042.oindex "&%-bpru%&"
3043This option is a combination of &%-bpr%& and &%-bpu%&.
168e428f
PH
3044
3045
9b371988
PH
3046.vitem &%-bpu%&
3047.oindex "&%-bpu%&"
3048This option operates like &%-bp%& but shows only undelivered top-level
3049addresses for each message displayed. Addresses generated by aliasing or
3050forwarding are not shown, unless the message was deferred after processing by a
3051router with the &%one_time%& option set.
168e428f
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3052
3053
9b371988
PH
3054.vitem &%-brt%&
3055.oindex "&%-brt%&"
3056.cindex "testing" "retry configuration"
3057.cindex "retry" "configuration testing"
168e428f
PH
3058This option is for testing retry rules, and it must be followed by up to three
3059arguments. It causes Exim to look for a retry rule that matches the values
3060and to write it to the standard output. For example:
9b371988
PH
3061.code
3062exim -brt bach.comp.mus.example
3063Retry rule: *.comp.mus.example F,2h,15m; F,4d,30m;
3064.endd
3065See chapter &<<CHAPretry>>& for a description of Exim's retry rules. The first
168e428f 3066argument, which is required, can be a complete address in the form
4f578862
PH
3067&'local_part@domain'&, or it can be just a domain name. If the second argument
3068contains a dot, it is interpreted as an optional second domain name; if no
3069retry rule is found for the first argument, the second is tried. This ties in
3070with Exim's behaviour when looking for retry rules for remote hosts &-- if no
3071rule is found that matches the host, one that matches the mail domain is
3072sought. Finally, an argument that is the name of a specific delivery error, as
3073used in setting up retry rules, can be given. For example:
3074.code
3075exim -brt haydn.comp.mus.example quota_3d
3076Retry rule: *@haydn.comp.mus.example quota_3d F,1h,15m
3077.endd
168e428f 3078