Update for eximstats 1.58
[exim.git] / doc / doc-docbook / spec.xfpt
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33393583 1. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.15 2007/02/26 14:06:33 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
21. Philip Hazel is developing in odd moments as a less cumbersome way of making
22. PostScript and PDFs than using xmlto and fop. They will be ignored by all
23. other XML processors.
24. /////////////////////////////////////////////////////////////////////////////
25
26.literal xml
27<?sdop
28 toc_chapter_blanks="yes,yes"
29 table_warn_soft_overflow="no"
30?>
31.literal off
9b371988 32
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33. /////////////////////////////////////////////////////////////////////////////
34. This generate the outermost <book> element that wraps then entire document.
35. /////////////////////////////////////////////////////////////////////////////
36
37.book
38
39. /////////////////////////////////////////////////////////////////////////////
40. These definitions set some parameters and save some typing. Remember that
41. the <bookinfo> element must also be updated for each new edition.
42. /////////////////////////////////////////////////////////////////////////////
43
44.set ACL "access control lists (ACLs)"
45.set previousversion "4.63"
46.set version "4.66"
47
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48
49. /////////////////////////////////////////////////////////////////////////////
50. Additional xfpt markup used by this document, over and above the default
51. provided in the xfpt library.
52. /////////////////////////////////////////////////////////////////////////////
53
54. --- Override the &$ flag to automatically insert a $ with the variable name
55
56.flag &$ $& "<varname>$" "</varname>"
57
58. --- Short flags for daggers in option headings. They will always be inside
59. --- an italic string, but we want the daggers to be roman.
60
61.flag &!! "</emphasis>&dagger;<emphasis>"
62.flag &!? "</emphasis>&Dagger;<emphasis>"
63
64. --- A macro for an Exim option definition heading, generating a one-line
65. --- table with four columns.
66
67.macro option
3cb1b51e 68.oindex "&%$1%&"
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69.itable all 0 0 4 8* left 5* center 5* center 6* right
70.row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&"
71.endtable
72.endmacro
73
74. --- A macro for the common 2-column tables. The width of the first column
75. --- is suitable for the many tables at the start of the main options chapter;
76. --- the small number of other 2-column tables override it.
77
db9452a9 78.macro table2 196pt 254pt
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79.itable none 0 0 2 $1 left $2 left
80.endmacro
81
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82. --- Macros for the concept and option index entries. For a "range" style of
83. --- entry, use .scindex for the start and .ecindex for the end. The first
84. --- argument of .scindex and the only argument of .ecindex must be the ID
85. --- that ties them together.
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86
87.macro cindex
88&<indexterm role="concept">&
89&<primary>&$1&</primary>&
90.arg 2
91&<secondary>&$2&</secondary>&
92.endarg
93&</indexterm>&
94.endmacro
95
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96.macro scindex
97&<indexterm role="concept" id="$1" class="startofrange">&
98&<primary>&$2&</primary>&
99.arg 3
100&<secondary>&$3&</secondary>&
101.endarg
102&</indexterm>&
103.endmacro
104
105.macro ecindex
106&<indexterm role="concept" startref="$1" class="endofrange"/>&
107.endmacro
108
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109.macro oindex
110&<indexterm role="option">&
111&<primary>&$1&</primary>&
112.arg 2
113&<secondary>&$2&</secondary>&
114.endarg
115&</indexterm>&
116.endmacro
117
118.macro index
119.echo "** Don't use .index; use .cindex or .oindex"
120.endmacro
121. ////////////////////////////////////////////////////////////////////////////
122
123
124. ////////////////////////////////////////////////////////////////////////////
125. The <bookinfo> element is removed from the XML before processing for Ascii
126. output formats.
127. ////////////////////////////////////////////////////////////////////////////
128
129.literal xml
130<bookinfo>
131<title>Specification of the Exim Mail Transfer Agent</title>
132<titleabbrev>The Exim MTA</titleabbrev>
ad268134 133<date>08 January 2007</date>
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134<author><firstname>Philip</firstname><surname>Hazel</surname></author>
135<authorinitials>PH</authorinitials>
136<affiliation><orgname>University of Cambridge Computing Service</orgname></affiliation>
137<address>New Museums Site, Pembroke Street, Cambridge CB2 3QH, England</address>
138<revhistory><revision>
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139 <revnumber>4.66</revnumber>
140 <date>08 January 2007</date>
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141 <authorinitials>PH</authorinitials>
142</revision></revhistory>
ad268134 143<copyright><year>2007</year><holder>University of Cambridge</holder></copyright>
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144</bookinfo>
145.literal off
146
147
148. /////////////////////////////////////////////////////////////////////////////
149. This chunk of literal XML implements index entries of the form "x, see y" and
150. "x, see also y". However, the DocBook DTD doesn't allow <indexterm> entries
151. at the top level, so we have to put the .chapter directive first.
152. /////////////////////////////////////////////////////////////////////////////
153
154.chapter "Introduction"
155.literal xml
156
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157<indexterm role="concept">
158 <primary>$1, $2, etc.</primary>
159 <see><emphasis>numerical variables</emphasis></see>
160</indexterm>
161<indexterm role="concept">
162 <primary>address</primary>
163 <secondary>rewriting</secondary>
164 <see><emphasis>rewriting</emphasis></see>
165</indexterm>
166<indexterm role="concept">
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167 <primary>Bounce Address Tag Validation</primary>
168 <see><emphasis>BATV</emphasis></see>
169</indexterm>
170<indexterm role="concept">
171 <primary>Client SMTP Authorization</primary>
172 <see><emphasis>CSA</emphasis></see>
173</indexterm>
174<indexterm role="concept">
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175 <primary>CR character</primary>
176 <see><emphasis>carriage return</emphasis></see>
177</indexterm>
178<indexterm role="concept">
179 <primary>CRL</primary>
180 <see><emphasis>certificate revocation list</emphasis></see>
181</indexterm>
182<indexterm role="concept">
183 <primary>delivery</primary>
184 <secondary>failure report</secondary>
185 <see><emphasis>bounce message</emphasis></see>
186</indexterm>
187<indexterm role="concept">
188 <primary>dialup</primary>
189 <see><emphasis>intermittently connected hosts</emphasis></see>
190</indexterm>
191<indexterm role="concept">
192 <primary>exiscan</primary>
193 <see><emphasis>content scanning</emphasis></see>
194</indexterm>
195<indexterm role="concept">
196 <primary>failover</primary>
197 <see><emphasis>fallback</emphasis></see>
198</indexterm>
199<indexterm role="concept">
200 <primary>fallover</primary>
201 <see><emphasis>fallback</emphasis></see>
202</indexterm>
203<indexterm role="concept">
204 <primary>filter</primary>
205 <secondary>Sieve</secondary>
206 <see><emphasis>Sieve filter</emphasis></see>
207</indexterm>
208<indexterm role="concept">
209 <primary>ident</primary>
210 <see><emphasis>RFC 1413</emphasis></see>
211</indexterm>
212<indexterm role="concept">
213 <primary>LF character</primary>
214 <see><emphasis>linefeed</emphasis></see>
215</indexterm>
216<indexterm role="concept">
217 <primary>maximum</primary>
218 <see><emphasis>limit</emphasis></see>
219</indexterm>
220<indexterm role="concept">
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221 <primary>monitor</primary>
222 <see><emphasis>Exim monitor</emphasis></see>
223</indexterm>
224<indexterm role="concept">
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225 <primary>no_<emphasis>xxx</emphasis></primary>
226 <see>entry for xxx</see>
227</indexterm>
228<indexterm role="concept">
229 <primary>NUL</primary>
230 <see><emphasis>binary zero</emphasis></see>
231</indexterm>
232<indexterm role="concept">
233 <primary>passwd file</primary>
234 <see><emphasis>/etc/passwd</emphasis></see>
235</indexterm>
236<indexterm role="concept">
237 <primary>process id</primary>
238 <see><emphasis>pid</emphasis></see>
239</indexterm>
240<indexterm role="concept">
241 <primary>RBL</primary>
242 <see><emphasis>DNS list</emphasis></see>
243</indexterm>
244<indexterm role="concept">
245 <primary>redirection</primary>
246 <see><emphasis>address redirection</emphasis></see>
247</indexterm>
248<indexterm role="concept">
249 <primary>return path</primary>
250 <seealso><emphasis>envelope sender</emphasis></seealso>
251</indexterm>
252<indexterm role="concept">
253 <primary>scanning</primary>
254 <see><emphasis>content scanning</emphasis></see>
255</indexterm>
256<indexterm role="concept">
257 <primary>SSL</primary>
258 <see><emphasis>TLS</emphasis></see>
259</indexterm>
260<indexterm role="concept">
261 <primary>string</primary>
262 <secondary>expansion</secondary>
263 <see><emphasis>expansion</emphasis></see>
264</indexterm>
265<indexterm role="concept">
266 <primary>top bit</primary>
267 <see><emphasis>8-bit characters</emphasis></see>
268</indexterm>
269<indexterm role="concept">
270 <primary>variables</primary>
271 <see><emphasis>expansion, variables</emphasis></see>
272</indexterm>
273<indexterm role="concept">
274 <primary>zero, binary</primary>
275 <see><emphasis>binary zero</emphasis></see>
276</indexterm>
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277
278.literal off
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279
280
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281. /////////////////////////////////////////////////////////////////////////////
282. This is the real start of the first chapter. See the comment above as to why
283. we can't have the .chapter line here.
284. chapter "Introduction"
285. /////////////////////////////////////////////////////////////////////////////
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286
287Exim is a mail transfer agent (MTA) for hosts that are running Unix or
288Unix-like operating systems. It was designed on the assumption that it would be
289run on hosts that are permanently connected to the Internet. However, it can be
290used on intermittently connected hosts with suitable configuration adjustments.
291
292Configuration files currently exist for the following operating systems: AIX,
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293BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, Dragonfly, FreeBSD, GNU/Hurd,
294GNU/Linux, HI-OSF (Hitachi), HI-UX, HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD,
295OpenUNIX, QNX, SCO, SCO SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4,
296Tru64-Unix (formerly Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware.
297Some of these operating systems are no longer current and cannot easily be
298tested, so the configuration files may no longer work in practice.
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299
300There are also configuration files for compiling Exim in the Cygwin environment
301that can be installed on systems running Windows. However, this document does
302not contain any information about running Exim in the Cygwin environment.
303
304The terms and conditions for the use and distribution of Exim are contained in
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305the file &_NOTICE_&. Exim is distributed under the terms of the GNU General
306Public Licence, a copy of which may be found in the file &_LICENCE_&.
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307
308The use, supply or promotion of Exim for the purpose of sending bulk,
309unsolicited electronic mail is incompatible with the basic aims of the program,
310which revolve around the free provision of a service that enhances the quality
311of personal communications. The author of Exim regards indiscriminate
312mass-mailing as an antisocial, irresponsible abuse of the Internet.
313
314Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
315experience of running and working on the Smail 3 code, I could never have
316contemplated starting to write a new MTA. Many of the ideas and user interfaces
317were originally taken from Smail 3, though the actual code of Exim is entirely
318new, and has developed far beyond the initial concept.
319
320Many people, both in Cambridge and around the world, have contributed to the
321development and the testing of Exim, and to porting it to various operating
322systems. I am grateful to them all. The distribution now contains a file called
9b371988 323&_ACKNOWLEDGMENTS_&, in which I have started recording the names of
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324contributors.
325
326
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327.section "Exim documentation"
328.new
329.cindex "documentation"
330This edition of the Exim specification applies to version &version; of Exim.
331Substantive changes from the &previousversion; edition are marked in some
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332renditions of the document; this paragraph is so marked if the rendition is
333capable of showing a change indicator.
9b371988 334.wen
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335
336This document is very much a reference manual; it is not a tutorial. The reader
337is expected to have some familiarity with the SMTP mail transfer protocol and
338with general Unix system administration. Although there are some discussions
339and examples in places, the information is mostly organized in a way that makes
340it easy to look up, rather than in a natural order for sequential reading.
341Furthermore, the manual aims to cover every aspect of Exim in detail, including
342a number of rarely-used, special-purpose features that are unlikely to be of
343very wide interest.
344
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345.cindex "books about Exim"
346An &"easier"& discussion of Exim which provides more in-depth explanatory,
347introductory, and tutorial material can be found in a book entitled &'The Exim
348SMTP Mail Server'&, published by UIT Cambridge
349(&url(http://www.uit.co.uk/exim-book/)).
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350
351This book also contains a chapter that gives a general introduction to SMTP and
352Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
353with the latest release of Exim. (Note that the earlier book about Exim,
354published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
355
9b371988 356.cindex "Debian" "information sources"
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357If you are using a Debian distribution of Exim, you will find information about
358Debian-specific features in the file
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359.display
360&_/usr/share/doc/exim4-base/README.Debian_&
361.endd
362The command &(man update-exim.conf)& is another source of Debian-specific
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363information.
364
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365.cindex "&_doc/NewStuff_&"
366.cindex "&_doc/ChangeLog_&"
367.cindex "change log"
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368As the program develops, there may be features in newer versions that have not
369yet made it into this document, which is updated only when the most significant
370digit of the fractional part of the version number changes. Specifications of
371new features that are not yet in this manual are placed in the file
9b371988 372&_doc/NewStuff_& in the Exim distribution.
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9b371988 374Some features may be classified as &"experimental"&. These may change
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375incompatibly while they are developing, or even be withdrawn. For this reason,
376they are not documented in this manual. Information about experimental features
9b371988 377can be found in the file &_doc/experimental.txt_&.
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378
379All changes to the program (whether new features, bug fixes, or other kinds of
9b371988 380change) are noted briefly in the file called &_doc/ChangeLog_&.
168e428f 381
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382.cindex "&_doc/spec.txt_&"
383This specification itself is available as an ASCII file in &_doc/spec.txt_& so
384that it can easily be searched with a text editor. Other files in the &_doc_&
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385directory are:
386
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387.table2 100pt
388.row &_OptionLists.txt_& "list of all options in alphabetical order"
389.row &_dbm.discuss.txt_& "discussion about DBM libraries"
390.row &_exim.8_& "a man page of Exim's command line options"
391.row &_experimental.txt_& "documentation of experimental features"
392.row &_filter.txt_& "specification of the filter language"
393.row &_pcrepattern.txt_& "specification of PCRE regular expressions"
394.row &_pcretest.txt_& "specification of the PCRE testing program"
395.row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
396.row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
397.endtable
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398
399The main specification and the specification of the filtering language are also
400available in other formats (HTML, PostScript, PDF, and Texinfo). Section
9b371988 401&<<SECTavail>>& below tells you how to get hold of these.
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402
403
404
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405.section "FTP and web sites"
406.cindex "web site"
407.cindex "FTP site"
068aaea8 408The primary site for Exim source distributions is currently the University of
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409Cambridge's FTP site, whose contents are described in &'Where to find the Exim
410distribution'& below. In addition, there is a web site and an FTP site at
411&%exim.org%&. These are now also hosted at the University of Cambridge. The
412&%exim.org%& site was previously hosted for a number of years by Energis
413Squared, formerly Planet Online Ltd, whose support I gratefully acknowledge.
414
415.cindex "wiki"
416.cindex "FAQ"
168e428f 417As well as Exim distribution tar files, the Exim web site contains a number of
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418differently formatted versions of the documentation, including the FAQ in both
419text and HTML formats. The HTML version comes with a keyword-in-context index.
420A recent addition to the online information is the Exim wiki
421(&url(http://www.exim.org/eximwiki/)). We hope that this will make it easier
422for Exim users to contribute examples, tips, and know-how for the benefit of
423others.
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424
425
426
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427.section "Mailing lists"
428.cindex "mailing lists" "for Exim users"
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429The following are the three main Exim mailing lists:
430
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431.table2 140pt
432.row &'exim-users@exim.org'& "general discussion list"
433.row &'exim-dev@exim.org'& "discussion of bugs, enhancements, etc."
434.row &'exim-announce@exim.org'& "moderated, low volume announcements list"
435.endtable
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436
437You can subscribe to these lists, change your existing subscriptions, and view
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438or search the archives via the mailing lists link on the Exim home page.
439.cindex "Debian" "mailing list for"
4f578862 440If you are using a Debian distribution of Exim, you may wish to subscribe to
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441the Debian-specific mailing list &'pkg-exim4-users@lists.alioth.debian.org'&
442via this web page:
443.display
444&url(http://lists.alioth.debian.org/mailman/listinfo/pkg-exim4-users)
445.endd
446Please ask Debian-specific questions on this list and not on the general Exim
447lists.
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448
449.section "Exim training"
450.cindex "training courses"
068aaea8 451From time to time (approximately annually at the time of writing), training
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452courses are run by the author of Exim in Cambridge, UK. Details of any
453forthcoming courses can be found on the web site
454&url(http://www-tus.csx.cam.ac.uk/courses/exim/).
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455
456
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457.section "Bug reports"
458.cindex "bug reports"
459.cindex "reporting bugs"
460Reports of obvious bugs should be emailed to &'bugs@exim.org'&. However, if you
461are unsure whether some behaviour is a bug or not, the best thing to do is to
462post a message to the &'exim-dev'& mailing list and have it discussed.
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463
464
465
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466.section "Where to find the Exim distribution" "SECTavail"
467.cindex "FTP site"
468.cindex "distribution" "ftp site"
168e428f 469The master ftp site for the Exim distribution is
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470.display
471&*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim*&
472.endd
168e428f 473This is mirrored by
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474.display
475&*ftp://ftp.exim.org/pub/exim*&
476.endd
477The file references that follow are relative to the &_exim_& directories at
478these sites. There are now quite a number of independent mirror sites around
479the world. Those that I know about are listed in the file called &_Mirrors_&.
480
481Within the &_exim_& directory there are subdirectories called &_exim3_& (for
482previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
483distributions), and &_Testing_& for testing versions. In the &_exim4_&
168e428f 484subdirectory, the current release can always be found in files called
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485.display
486&_exim-n.nn.tar.gz_&
487&_exim-n.nn.tar.bz2_&
488.endd
489where &'n.nn'& is the highest such version number in the directory. The two
168e428f 490files contain identical data; the only difference is the type of compression.
9b371988 491The &_.bz2_& file is usually a lot smaller than the &_.gz_& file.
168e428f 492
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493.cindex "distribution" "signing details"
494.cindex "distribution" "public key"
495.cindex "public key for signed distribution"
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496The distributions are currently signed with Philip Hazel's GPG key. The
497corresponding public key is available from a number of keyservers, and there is
9b371988 498also a copy in the file &_Public-Key_&. The signatures for the tar bundles are
168e428f 499in:
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500.display
501&_exim-n.nn.tar.gz.sig_&
502&_exim-n.nn.tar.bz2.sig_&
503.endd
168e428f 504For each released version, the log of changes is made separately available in a
9b371988 505separate file in the directory &_ChangeLogs_& so that it is possible to
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506find out what has changed without having to download the entire distribution.
507
9b371988 508.cindex "documentation" "available formats"
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509The main distribution contains ASCII versions of this specification and other
510documentation; other formats of the documents are available in separate files
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511inside the &_exim4_& directory of the FTP site:
512.display
513&_exim-html-n.nn.tar.gz_&
514&_exim-pdf-n.nn.tar.gz_&
515&_exim-postscript-n.nn.tar.gz_&
516&_exim-texinfo-n.nn.tar.gz_&
517.endd
518These tar files contain only the &_doc_& directory, not the complete
519distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
520.cindex "FAQ"
168e428f 521The FAQ is available for downloading in two different formats in these files:
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522.display
523&_exim4/FAQ.txt.gz_&
524&_exim4/FAQ.html.tar.gz_&
525.endd
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526The first of these is a single ASCII file that can be searched with a text
527editor. The second is a directory of HTML files, normally accessed by starting
9b371988 528at &_index.html_&. The HTML version of the FAQ (which is also included in the
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529HTML documentation tarbundle) includes a keyword-in-context index, which is
530often the most convenient way of finding your way around.
531
532
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533.section "Wish list"
534.cindex "wish list"
168e428f 535A wish list is maintained, containing ideas for new features that have been
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536submitted. This used to be a single file that from time to time was exported to
537the ftp site into the file &_exim4/WishList_&. However, it has now been
538imported into Exim's Bugzilla data.
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539
540
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541.section "Contributed material"
542.cindex "contributed material"
543At the ftp site, there is a directory called &_Contrib_& that contains
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544miscellaneous files contributed to the Exim community by Exim users. There is
545also a collection of contributed configuration examples in
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546&_exim4/config.samples.tar.gz_&. These samples are referenced from the FAQ.
547
548
549
550.section "Limitations"
551.ilist
552.cindex "limitations of Exim"
553.cindex "bang paths" "not handled by Exim"
554Exim is designed for use as an Internet MTA, and therefore handles addresses in
555RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
556simple two-component bang paths can be converted by a straightforward rewriting
557configuration. This restriction does not prevent Exim from being interfaced to
558UUCP as a transport mechanism, provided that domain addresses are used.
559.next
560.cindex "domainless addresses"
561.cindex "address" "without domain"
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562Exim insists that every address it handles has a domain attached. For incoming
563local messages, domainless addresses are automatically qualified with a
564configured domain value. Configuration options specify from which remote
565systems unqualified addresses are acceptable. These are then qualified on
566arrival.
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567.next
568.cindex "transport" "external"
569.cindex "external transports"
570The only external transport mechanisms that are currently implemented are SMTP
571and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
168e428f 572transport is available, and there are facilities for writing messages to files
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573and pipes, optionally in &'batched SMTP'& format; these facilities can be used
574to send messages to other transport mechanisms such as UUCP, provided they can
575handle domain-style addresses. Batched SMTP input is also catered for.
576.next
577Exim is not designed for storing mail for dial-in hosts. When the volumes of
578such mail are large, it is better to get the messages &"delivered"& into files
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579(that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
580other means.
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581.next
582Although Exim does have basic facilities for scanning incoming messages, these
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583are not comprehensive enough to do full virus or spam scanning. Such operations
584are best carried out using additional specialized software packages. If you
585compile Exim with the content-scanning extension, straightforward interfaces to
586a number of common scanners are provided.
9b371988 587.endlist
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588
589
9b371988 590.section "Run time configuration"
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591Exim's run time configuration is held in a single text file that is divided
592into a number of sections. The entries in this file consist of keywords and
593values, in the style of Smail 3 configuration files. A default configuration
594file which is suitable for simple online installations is provided in the
9b371988 595distribution, and is described in chapter &<<CHAPdefconfil>>& below.
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596
597
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598.section "Calling interface"
599.cindex "Sendmail compatibility" "command line interface"
168e428f 600Like many MTAs, Exim has adopted the Sendmail command line interface so that it
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601can be a straight replacement for &_/usr/lib/sendmail_& or
602&_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
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603about Sendmail in order to run Exim. For actions other than sending messages,
604Sendmail-compatible options also exist, but those that produce output (for
9b371988 605example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
168e428f 606format. There are also some additional options that are compatible with Smail
9b371988 6073, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
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608documents all Exim's command line options. This information is automatically
609made into the man page that forms part of the Exim distribution.
610
611Control of messages on the queue can be done via certain privileged command
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612line options. There is also an optional monitor program called &'eximon'&,
613which displays current information in an X window, and which contains a menu
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614interface to Exim's command line administration options.
615
616
617
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618.section "Terminology"
619.cindex "terminology definitions"
620.cindex "body of message" "definition of"
621The &'body'& of a message is the actual data that the sender wants to transmit.
622It is the last part of a message, and is separated from the &'header'& (see
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623below) by a blank line.
624
9b371988 625.cindex "bounce message" "definition of"
168e428f 626When a message cannot be delivered, it is normally returned to the sender in a
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627delivery failure message or a &"non-delivery report"& (NDR). The term
628&'bounce'& is commonly used for this action, and the error reports are often
629called &'bounce messages'&. This is a convenient shorthand for &"delivery
630failure error report"&. Such messages have an empty sender address in the
631message's &'envelope'& (see below) to ensure that they cannot themselves give
632rise to further bounce messages.
633
634The term &'default'& appears frequently in this manual. It is used to qualify a
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635value which is used in the absence of any setting in the configuration. It may
636also qualify an action which is taken unless a configuration setting specifies
637otherwise.
638
9b371988 639The term &'defer'& is used when the delivery of a message to a specific
168e428f 640destination cannot immediately take place for some reason (a remote host may be
9b371988 641down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
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642until a later time.
643
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644The word &'domain'& is sometimes used to mean all but the first component of a
645host's name. It is &'not'& used in that sense here, where it normally refers to
646the part of an email address following the @ sign.
168e428f 647
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648.cindex "envelope" "definition of"
649.cindex "sender" "definition of"
650A message in transit has an associated &'envelope'&, as well as a header and a
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651body. The envelope contains a sender address (to which bounce messages should
652be delivered), and any number of recipient addresses. References to the
653sender or the recipients of a message usually mean the addresses in the
654envelope. An MTA uses these addresses for delivery, and for returning bounce
655messages, not the addresses that appear in the header lines.
656
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657.cindex "message header" "definition of"
658.cindex "header section" "definition of"
659The &'header'& of a message is the first part of a message's text, consisting
660of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
661&'Subject:'&, etc. Long header lines can be split over several text lines by
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662indenting the continuations. The header is separated from the body by a blank
663line.
664
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665.cindex "local part" "definition of"
666.cindex "domain" "definition of"
667The term &'local part'&, which is taken from RFC 2822, is used to refer to that
168e428f 668part of an email address that precedes the @ sign. The part that follows the
9b371988 669@ sign is called the &'domain'& or &'mail domain'&.
168e428f 670
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671.cindex "local delivery" "definition of"
672.cindex "remote delivery" "definition of"
673The terms &'local delivery'& and &'remote delivery'& are used to distinguish
168e428f 674delivery to a file or a pipe on the local host from delivery by SMTP over
068aaea8 675TCP/IP to another host. As far as Exim is concerned, all hosts other than the
9b371988 676host it is running on are &'remote'&.
168e428f 677
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678.cindex "return path" "definition of"
679&'Return path'& is another name that is used for the sender address in a
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680message's envelope.
681
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682.cindex "queue" "definition of"
683The term &'queue'& is used to refer to the set of messages awaiting delivery,
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684because this term is in widespread use in the context of MTAs. However, in
685Exim's case the reality is more like a pool than a queue, because there is
686normally no ordering of waiting messages.
687
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688.cindex "queue runner" "definition of"
689The term &'queue runner'& is used to describe a process that scans the queue
168e428f 690and attempts to deliver those messages whose retry times have come. This term
9b371988 691is used by other MTAs, and also relates to the command &%runq%&, but in Exim
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692the waiting messages are normally processed in an unpredictable order.
693
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694.cindex "spool directory" "definition of"
695The term &'spool directory'& is used for a directory in which Exim keeps the
696messages on its queue &-- that is, those that it is in the process of
168e428f 697delivering. This should not be confused with the directory in which local
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698mailboxes are stored, which is called a &"spool directory"& by some people. In
699the Exim documentation, &"spool"& is always used in the first sense.
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700
701
702
703
704
705
9b371988
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706. ////////////////////////////////////////////////////////////////////////////
707. ////////////////////////////////////////////////////////////////////////////
168e428f 708
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709.chapter "Incorporated code"
710.cindex "incorporated code"
711.cindex "regular expressions" "library"
712.cindex "PCRE"
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713A number of pieces of external code are included in the Exim distribution.
714
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715.ilist
716Regular expressions are supported in the main Exim program and in the Exim
717monitor using the freely-distributable PCRE library, copyright &copy;
718University of Cambridge. The source is distributed in the directory
719&_src/pcre_&. However, this is a cut-down version of PCRE. If you want to use
720the PCRE library in other programs, you should obtain and install the full
4f578862 721version from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
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722.next
723.cindex "cdb" "acknowledgement"
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724Support for the cdb (Constant DataBase) lookup method is provided by code
725contributed by Nigel Metheringham of (at the time he contributed it) Planet
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726Online Ltd. The implementation is completely contained within the code of Exim.
727It does not link against an external cdb library. The code contains the
728following statements:
729
730.blockquote
731Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
732
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733This program is free software; you can redistribute it and/or modify it under
734the terms of the GNU General Public License as published by the Free Software
735Foundation; either version 2 of the License, or (at your option) any later
736version.
9b371988 737
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738This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
739the spec and sample code for cdb can be obtained from
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740&url(http://www.pobox.com/~djb/cdb.html). This implementation borrows some
741code from Dan Bernstein's implementation (which has no license restrictions
742applied to it).
743.endblockquote
744.next
745.cindex "SPA authentication"
746.cindex "Samba project"
747.cindex "Microsoft Secure Password Authentication"
748Client support for Microsoft's &'Secure Password Authentication'& is provided
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749by code contributed by Marc Prud'hommeaux. Server support was contributed by
750Tom Kistner. This includes code taken from the Samba project, which is released
751under the Gnu GPL.
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752.next
753.cindex "Cyrus"
754.cindex "&'pwcheck'& daemon"
755.cindex "&'pwauthd'& daemon"
756Support for calling the Cyrus &'pwcheck'& and &'saslauthd'& daemons is provided
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757by code taken from the Cyrus-SASL library and adapted by Alexander S.
758Sabourenkov. The permission notice appears below, in accordance with the
759conditions expressed therein.
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760
761.blockquote
762Copyright &copy; 2001 Carnegie Mellon University. All rights reserved.
763
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764Redistribution and use in source and binary forms, with or without
765modification, are permitted provided that the following conditions
766are met:
168e428f 767
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768.olist
769Redistributions of source code must retain the above copyright
770notice, this list of conditions and the following disclaimer.
771.next
772Redistributions in binary form must reproduce the above copyright
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773notice, this list of conditions and the following disclaimer in
774the documentation and/or other materials provided with the
775distribution.
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776.next
777The name &"Carnegie Mellon University"& must not be used to
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778endorse or promote products derived from this software without
779prior written permission. For permission or any other legal
780details, please contact
9b371988 781.display
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782 Office of Technology Transfer
783 Carnegie Mellon University
784 5000 Forbes Avenue
785 Pittsburgh, PA 15213-3890
786 (412) 268-4387, fax: (412) 268-7395
787 tech-transfer@andrew.cmu.edu
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788.endd
789.next
790Redistributions of any form whatsoever must retain the following
168e428f 791acknowledgment:
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792
793&"This product includes software developed by Computing Services
794at Carnegie Mellon University (&url(http://www.cmu.edu/computing/)."&
795
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796CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
797THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
798AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
799FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
800WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
801AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
802OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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803.endlist
804.endblockquote
168e428f 805
9b371988
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806.next
807.cindex "Exim monitor" "acknowledgement"
808.cindex "X-windows"
809.cindex "Athena"
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810The Exim Monitor program, which is an X-Window application, includes
811modified versions of the Athena StripChart and TextPop widgets.
812This code is copyright by DEC and MIT, and their permission notice appears
813below, in accordance with the conditions expressed therein.
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814
815.blockquote
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816Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
817and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
9b371988 818
168e428f 819All Rights Reserved
9b371988 820
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821Permission to use, copy, modify, and distribute this software and its
822documentation for any purpose and without fee is hereby granted,
823provided that the above copyright notice appear in all copies and that
824both that copyright notice and this permission notice appear in
825supporting documentation, and that the names of Digital or MIT not be
826used in advertising or publicity pertaining to distribution of the
827software without specific, written prior permission.
9b371988 828
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829DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
830ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
831DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
832ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
833WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
834ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
835SOFTWARE.
9b371988 836.endblockquote
168e428f 837
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838.next
839Many people have contributed code fragments, some large, some small, that were
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840not covered by any specific licence requirements. It is assumed that the
841contributors are happy to see their code incoporated into Exim under the GPL.
9b371988 842.endlist
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843
844
845
846
847
9b371988
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848. ////////////////////////////////////////////////////////////////////////////
849. ////////////////////////////////////////////////////////////////////////////
168e428f 850
9b371988
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851.chapter "How Exim receives and delivers mail" "" &&&
852 "Receiving and delivering mail"
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853
854
9b371988
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855.section "Overall philosophy"
856.cindex "design philosophy"
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857Exim is designed to work efficiently on systems that are permanently connected
858to the Internet and are handling a general mix of mail. In such circumstances,
859most messages can be delivered immediately. Consequently, Exim does not
860maintain independent queues of messages for specific domains or hosts, though
861it does try to send several messages in a single SMTP connection after a host
862has been down, and it also maintains per-host retry information.
863
864
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865.section "Policy control"
866.cindex "policy control" "overview"
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867Policy controls are now an important feature of MTAs that are connected to the
868Internet. Perhaps their most important job is to stop MTAs being abused as
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869&"open relays"& by misguided individuals who send out vast amounts of
870unsolicited junk, and want to disguise its source. Exim provides flexible
871facilities for specifying policy controls on incoming mail:
168e428f 872
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873.ilist
874.cindex "&ACL;" "introduction"
168e428f 875Exim 4 (unlike previous versions of Exim) implements policy controls on
9b371988 876incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
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877series of statements that may either grant or deny access. ACLs can be used at
878several places in the SMTP dialogue while receiving a message from a remote
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879host. However, the most common places are after each RCPT command, and at the
880very end of the message. The sysadmin can specify conditions for accepting or
881rejecting individual recipients or the entire message, respectively, at these
882two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
168e428f 883error code.
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884.next
885An ACL is also available for locally generated, non-SMTP messages. In this
168e428f 886case, the only available actions are to accept or deny the entire message.
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887.next
888When Exim is compiled with the content-scanning extension, facilities are
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889provided in the ACL mechanism for passing the message to external virus and/or
890spam scanning software. The result of such a scan is passed back to the ACL,
891which can then use it to decide what to do with the message.
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892.next
893When a message has been received, either from a remote host or from the local
168e428f 894host, but before the final acknowledgement has been sent, a locally supplied C
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895function called &[local_scan()]& can be run to inspect the message and decide
896whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
897is accepted, the list of recipients can be modified by the function.
898.next
899Using the &[local_scan()]& mechanism is another way of calling external scanner
900software. The &%SA-Exim%& add-on package works this way. It does not require
901Exim to be compiled with the content-scanning extension.
902.next
903After a message has been accepted, a further checking mechanism is available in
904the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
905runs at the start of every delivery process.
906.endlist
907
908
909
910.section "User filters"
911.cindex "filter" "introduction"
912.cindex "Sieve filter"
168e428f 913In a conventional Exim configuration, users are able to run private filters by
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914setting up appropriate &_.forward_& files in their home directories. See
915chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
916configuration needed to support this, and the separate document entitled
917&'Exim's interfaces to mail filtering'& for user details. Two different kinds
918of filtering are available:
919
920.ilist
921Sieve filters are written in the standard filtering language that is defined
168e428f 922by RFC 3028.
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923.next
924Exim filters are written in a syntax that is unique to Exim, but which is more
168e428f 925powerful than Sieve, which it pre-dates.
9b371988 926.endlist
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927
928User filters are run as part of the routing process, described below.
929
930
931
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932.section "Message identification" "SECTmessiden"
933.cindex "message ids" "details of format"
934.cindex "format" "of message id"
935.cindex "id of message"
936.cindex "base62"
937.cindex "base36"
938.cindex "Darwin"
939.cindex "Cygwin"
940Every message handled by Exim is given a &'message id'& which is sixteen
168e428f 941characters long. It is divided into three parts, separated by hyphens, for
9b371988 942example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
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943normally encoding numbers in base 62. However, in the Darwin operating
944system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
945(avoiding the use of lower case letters) is used instead, because the message
946id is used to construct file names, and the names of files in those systems are
068aaea8 947not always case-sensitive.
168e428f 948
9b371988 949.cindex "pid (process id)" "re-use of"
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950The detail of the contents of the message id have changed as Exim has evolved.
951Earlier versions relied on the operating system not re-using a process id (pid)
952within one second. On modern operating systems, this assumption can no longer
953be made, so the algorithm had to be changed. To retain backward compatibility,
954the format of the message id was retained, which is why the following rules are
955somewhat eccentric:
956
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957.ilist
958The first six characters of the message id are the time at which the message
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959started to be received, to a granularity of one second. That is, this field
960contains the number of seconds since the start of the epoch (the normal Unix
961way of representing the date and time of day).
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962.next
963After the first hyphen, the next six characters are the id of the process that
168e428f 964received the message.
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965.next
966There are two different possibilities for the final two characters:
967.olist
968.cindex "&%localhost_number%&"
969If &%localhost_number%& is not set, this value is the fractional part of the
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970time of reception, normally in units of 1/2000 of a second, but for systems
971that must use base 36 instead of base 62 (because of case-insensitive file
972systems), the units are 1/1000 of a second.
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973.next
974If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
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975the fractional part of the time, which in this case is in units of 1/200
976(1/100) of a second.
9b371988
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977.endlist
978.endlist
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979
980After a message has been received, Exim waits for the clock to tick at the
981appropriate resolution before proceeding, so that if another message is
982received by the same process, or by another process with the same (re-used)
983pid, it is guaranteed that the time will be different. In most cases, the clock
984will already have ticked while the message was being received.
985
986
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987.section "Receiving mail"
988.cindex "receiving mail"
989.cindex "message" "reception"
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990The only way Exim can receive mail from another host is using SMTP over
991TCP/IP, in which case the sender and recipient addresses are transferred using
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992SMTP commands. However, from a locally running process (such as a user's MUA),
993there are several possibilities:
994
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995.ilist
996If the process runs Exim with the &%-bm%& option, the message is read
168e428f 997non-interactively (usually via a pipe), with the recipients taken from the
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998command line, or from the body of the message if &%-t%& is also used.
999.next
1000If the process runs Exim with the &%-bS%& option, the message is also read
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1001non-interactively, but in this case the recipients are listed at the start of
1002the message in a series of SMTP RCPT commands, terminated by a DATA
9b371988 1003command. This is so-called &"batch SMTP"& format,
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1004but it isn't really SMTP. The SMTP commands are just another way of passing
1005envelope addresses in a non-interactive submission.
9b371988
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1006.next
1007If the process runs Exim with the &%-bs%& option, the message is read
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1008interactively, using the SMTP protocol. A two-way pipe is normally used for
1009passing data between the local process and the Exim process.
9b371988 1010This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
168e428f 1011example, the ACLs for SMTP commands are used for this form of submission.
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1012.next
1013A local process may also make a TCP/IP call to the host's loopback address
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1014(127.0.0.1) or any other of its IP addresses. When receiving messages, Exim
1015does not treat the loopback address specially. It treats all such connections
1016in the same way as connections from other hosts.
9b371988 1017.endlist
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1018
1019
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1020.cindex "message sender" "constructed by Exim"
1021.cindex "sender" "constructed by Exim"
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1022In the three cases that do not involve TCP/IP, the sender address is
1023constructed from the login name of the user that called Exim and a default
9b371988 1024qualification domain (which can be set by the &%qualify_domain%& configuration
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1025option). For local or batch SMTP, a sender address that is passed using the
1026SMTP MAIL command is ignored. However, the system administrator may allow
9b371988 1027certain users (&"trusted users"&) to specify a different sender address
168e428f 1028unconditionally, or all users to specify certain forms of different sender
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1029address. The &%-f%& option or the SMTP MAIL command is used to specify these
1030different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1031users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
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1032users to change sender addresses.
1033
1034Messages received by either of the non-interactive mechanisms are subject to
1035checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1036(either over TCP/IP, or interacting with a local process) can be checked by a
1037number of ACLs that operate at different times during the SMTP session. Either
1038individual recipients, or the entire message, can be rejected if local policy
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1039requirements are not met. The &[local_scan()]& function (see chapter
1040&<<CHAPlocalscan>>&) is run for all incoming messages.
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1041
1042Exim can be configured not to start a delivery process when a message is
1043received; this can be unconditional, or depend on the number of incoming SMTP
1044connections or the system load. In these situations, new messages wait on the
1045queue until a queue runner process picks them up. However, in standard
1046configurations under normal conditions, delivery is started as soon as a
1047message is received.
1048
1049
1050
1051
1052
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1053.section "Handling an incoming message"
1054.cindex "spool directory" "files that hold a message"
1055.cindex "file" "how a message is held"
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1056When Exim accepts a message, it writes two files in its spool directory. The
1057first contains the envelope information, the current status of the message, and
1058the header lines, and the second contains the body of the message. The names of
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1059the two spool files consist of the message id, followed by &`-H`& for the
1060file containing the envelope and header, and &`-D`& for the data file.
168e428f 1061
9b371988 1062.cindex "spool directory" "&_input_& sub-directory"
168e428f 1063By default all these message files are held in a single directory called
9b371988 1064&_input_& inside the general Exim spool directory. Some operating systems do
c0712871 1065not perform very well if the number of files in a directory gets large; to
9b371988 1066improve performance in such cases, the &%split_spool_directory%& option can be
168e428f 1067used. This causes Exim to split up the input files into 62 sub-directories
db9452a9 1068whose names are single letters or digits. When this is done, the queue is
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1069processed one sub-directory at a time instead of all at once, which can improve
1070overall performance even when there are not enough files in each directory to
db9452a9 1071affect file system performance.
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1072
1073The envelope information consists of the address of the message's sender and
1074the addresses of the recipients. This information is entirely separate from
1075any addresses contained in the header lines. The status of the message includes
1076a list of recipients who have already received the message. The format of the
9b371988 1077first spool file is described in chapter &<<CHAPspool>>&.
168e428f 1078
9b371988 1079.cindex "rewriting" "addresses"
168e428f 1080Address rewriting that is specified in the rewrite section of the configuration
9b371988 1081(see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
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1082both in the header lines and the envelope, at the time the message is accepted.
1083If during the course of delivery additional addresses are generated (for
1084example, via aliasing), these new addresses are rewritten as soon as they are
1085generated. At the time a message is actually delivered (transported) further
1086rewriting can take place; because this is a transport option, it can be
1087different for different forms of delivery. It is also possible to specify the
1088addition or removal of certain header lines at the time the message is
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1089delivered (see chapters &<<CHAProutergeneric>>& and
1090&<<CHAPtransportgeneric>>&).
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1091
1092
1093
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1094.section "Life of a message"
1095.cindex "message" "life of"
1096.cindex "message" "frozen"
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1097A message remains in the spool directory until it is completely delivered to
1098its recipients or to an error address, or until it is deleted by an
1099administrator or by the user who originally created it. In cases when delivery
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1100cannot proceed &-- for example, when a message can neither be delivered to its
1101recipients nor returned to its sender, the message is marked &"frozen"& on the
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1102spool, and no more deliveries are attempted.
1103
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1104.cindex "frozen messages" "thawing"
1105.cindex "message" "thawing frozen"
1106An administrator can &"thaw"& such messages when the problem has been
1107corrected, and can also freeze individual messages by hand if necessary. In
1108addition, an administrator can force a delivery error, causing a bounce message
1109to be sent.
1110
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1111.cindex "&%timeout_frozen_after%&"
1112.cindex "&%ignore_bounce_errors_after%&"
1113There are options called &%ignore_bounce_errors_after%& and
1114&%timeout_frozen_after%&, which discard frozen messages after a certain time.
068aaea8 1115The first applies only to frozen bounces, the second to any frozen messages.
168e428f 1116
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1117.cindex "message" "log file for"
1118.cindex "log" "file for each message"
168e428f 1119While Exim is working on a message, it writes information about each delivery
068aaea8 1120attempt to its main log file. This includes successful, unsuccessful, and
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1121delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1122lines are also written to a separate &'message log'& file for each message.
1123These logs are solely for the benefit of the administrator, and are normally
1124deleted along with the spool files when processing of a message is complete.
168e428f 1125The use of individual message logs can be disabled by setting
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1126&%no_message_logs%&; this might give an improvement in performance on very busy
1127systems.
168e428f 1128
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1129.cindex "journal file"
1130.cindex "file" "journal"
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1131All the information Exim itself needs to set up a delivery is kept in the first
1132spool file, along with the header lines. When a successful delivery occurs, the
1133address is immediately written at the end of a journal file, whose name is the
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1134message id followed by &`-J`&. At the end of a delivery run, if there are some
1135addresses left to be tried again later, the first spool file (the &`-H`& file)
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1136is updated to indicate which these are, and the journal file is then deleted.
1137Updating the spool file is done by writing a new file and renaming it, to
1138minimize the possibility of data loss.
1139
1140Should the system or the program crash after a successful delivery but before
1141the spool file has been updated, the journal is left lying around. The next
1142time Exim attempts to deliver the message, it reads the journal file and
1143updates the spool file before proceeding. This minimizes the chances of double
1144deliveries caused by crashes.
1145
1146
1147
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1148.section "Processing an address for delivery" "SECTprocaddress"
1149.cindex "drivers" "definition of"
1150.cindex "router" "definition of"
1151.cindex "transport" "definition of"
1152The main delivery processing elements of Exim are called &'routers'& and
1153&'transports'&, and collectively these are known as &'drivers'&. Code for a
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1154number of them is provided in the source distribution, and compile-time options
1155specify which ones are included in the binary. Run time options specify which
1156ones are actually used for delivering messages.
1157
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1158.cindex "drivers" "instance definition"
1159Each driver that is specified in the run time configuration is an &'instance'&
168e428f 1160of that particular driver type. Multiple instances are allowed; for example,
9b371988 1161you can set up several different &(smtp)& transports, each with different
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1162option values that might specify different ports or different timeouts. Each
1163instance has its own identifying name. In what follows we will normally use the
1164instance name when discussing one particular instance (that is, one specific
1165configuration of the driver), and the generic driver name when discussing
1166the driver's features in general.
1167
9b371988 1168A &'router'& is a driver that operates on an address, either determining how
068aaea8 1169its delivery should happen, by assigning it to a specific transport, or
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1170converting the address into one or more new addresses (for example, via an
1171alias file). A router may also explicitly choose to fail an address, causing it
1172to be bounced.
1173
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1174A &'transport'& is a driver that transmits a copy of the message from Exim's
1175spool to some destination. There are two kinds of transport: for a &'local'&
168e428f 1176transport, the destination is a file or a pipe on the local host, whereas for a
9b371988 1177&'remote'& transport the destination is some other host. A message is passed
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1178to a specific transport as a result of successful routing. If a message has
1179several recipients, it may be passed to a number of different transports.
1180
9b371988 1181.cindex "preconditions" "definition of"
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1182An address is processed by passing it to each configured router instance in
1183turn, subject to certain preconditions, until a router accepts the address or
1184specifies that it should be bounced. We will describe this process in more
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1185detail shortly. First, as a simple example, we consider how each recipient
1186address in a message is processed in a small configuration of three routers.
168e428f 1187
068aaea8 1188To make this a more concrete example, it is described in terms of some actual
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1189routers, but remember, this is only an example. You can configure Exim's
1190routers in many different ways, and there may be any number of routers in a
1191configuration.
1192
1193The first router that is specified in a configuration is often one that handles
1194addresses in domains that are not recognized specially by the local host. These
1195are typically addresses for arbitrary domains on the Internet. A precondition
1196is set up which looks for the special domains known to the host (for example,
9b371988 1197its own domain name), and the router is run for addresses that do &'not'&
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1198match. Typically, this is a router that looks up domains in the DNS in order to
1199find the hosts to which this address routes. If it succeeds, the address is
068aaea8 1200assigned to a suitable SMTP transport; if it does not succeed, the router is
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1201configured to fail the address.
1202
068aaea8 1203The second router is reached only when the domain is recognized as one that
9b371988 1204&"belongs"& to the local host. This router does redirection &-- also known as
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1205aliasing and forwarding. When it generates one or more new addresses from the
1206original, each of them is routed independently from the start. Otherwise, the
1207router may cause an address to fail, or it may simply decline to handle the
1208address, in which case the address is passed to the next router.
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1209
1210The final router in many configurations is one that checks to see if the
1211address belongs to a local mailbox. The precondition may involve a check to
1212see if the local part is the name of a login account, or it may look up the
1213local part in a file or a database. If its preconditions are not met, or if
1214the router declines, we have reached the end of the routers. When this happens,
1215the address is bounced.
1216
1217
1218
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1219.section "Processing an address for verification"
1220.cindex "router" "for verification"
1221.cindex "verifying address" "overview"
168e428f 1222As well as being used to decide how to deliver to an address, Exim's routers
9b371988 1223are also used for &'address verification'&. Verification can be requested as
168e428f 1224one of the checks to be performed in an ACL for incoming messages, on both
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1225sender and recipient addresses, and it can be tested using the &%-bv%& and
1226&%-bvs%& command line options.
168e428f 1227
9b371988 1228When an address is being verified, the routers are run in &"verify mode"&. This
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1229does not affect the way the routers work, but it is a state that can be
1230detected. By this means, a router can be skipped or made to behave differently
1231when verifying. A common example is a configuration in which the first router
1232sends all messages to a message-scanning program, unless they have been
1233previously scanned. Thus, the first router accepts all addresses without any
9b371988 1234checking, making it useless for verifying. Normally, the &%no_verify%& option
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1235would be set for such a router, causing it to be skipped in verify mode.
1236
1237
1238
1239
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1240.section "Running an individual router" "SECTrunindrou"
1241.cindex "router" "running details"
1242.cindex "preconditions" "checking"
1243.cindex "router" "result of running"
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1244As explained in the example above, a number of preconditions are checked before
1245running a router. If any are not met, the router is skipped, and the address is
9b371988 1246passed to the next router. When all the preconditions on a router &'are'& met,
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1247the router is run. What happens next depends on the outcome, which is one of
1248the following:
1249
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1250.ilist
1251&'accept'&: The router accepts the address, and either assigns it to a
1252transport, or generates one or more &"child"& addresses. Processing the
1253original address ceases,
1254.cindex "&%unseen%& option"
1255unless the &%unseen%& option is set on the router. This option
168e428f 1256can be used to set up multiple deliveries with different routing (for example,
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1257for keeping archive copies of messages). When &%unseen%& is set, the address is
1258passed to the next router. Normally, however, an &'accept'& return marks the
168e428f 1259end of routing.
9b371988 1260
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1261Any child addresses generated by the router are processed independently,
1262starting with the first router by default. It is possible to change this by
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1263setting the &%redirect_router%& option to specify which router to start at for
1264child addresses. Unlike &%pass_router%& (see below) the router specified by
1265&%redirect_router%& may be anywhere in the router configuration.
1266.next
1267&'pass'&: The router recognizes the address, but cannot handle it itself. It
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1268requests that the address be passed to another router. By default the address
1269is passed to the next router, but this can be changed by setting the
9b371988 1270&%pass_router%& option. However, (unlike &%redirect_router%&) the named router
168e428f 1271must be below the current router (to avoid loops).
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1272.next
1273&'decline'&: The router declines to accept the address because it does not
168e428f 1274recognize it at all. By default, the address is passed to the next router, but
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1275this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1276set, all the remaining routers are skipped. In effect, &%no_more%& converts
1277&'decline'& into &'fail'&.
1278.next
1279&'fail'&: The router determines that the address should fail, and queues it for
168e428f 1280the generation of a bounce message. There is no further processing of the
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1281original address unless &%unseen%& is set on the router.
1282.next
1283&'defer'&: The router cannot handle the address at the present time. (A
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1284database may be offline, or a DNS lookup may have timed out.) No further
1285processing of the address happens in this delivery attempt. It is tried again
1286next time the message is considered for delivery.
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1287.next
1288&'error'&: There is some error in the router (for example, a syntax error in
168e428f 1289its configuration). The action is as for defer.
9b371988 1290.endlist
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1291
1292If an address reaches the end of the routers without having been accepted by
068aaea8 1293any of them, it is bounced as unrouteable. The default error message in this
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1294situation is &"unrouteable address"&, but you can set your own message by
1295making use of the &%cannot_route_message%& option. This can be set for any
1296router; the value from the last router that &"saw"& the address is used.
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1297
1298Sometimes while routing you want to fail a delivery when some conditions are
1299met but others are not, instead of passing the address on for further routing.
1300You can do this by having a second router that explicitly fails the delivery
9b371988 1301when the relevant conditions are met. The &(redirect)& router has a &"fail"&
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1302facility for this purpose.
1303
1304
9b371988 1305.section "Duplicate addresses"
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1306.cindex "case of local parts"
1307.cindex "address duplicate" "discarding"
db9452a9 1308.cindex "duplicate addresses"
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1309Once routing is complete, Exim scans the addresses that are assigned to local
1310and remote transports, and discards any duplicates that it finds. During this
3cb1b51e 1311check, local parts are treated as case-sensitive. This happens only when
db9452a9 1312actually delivering a message; when testing routers with &%-bt%&, all the
3cb1b51e 1313routed addresses are shown.
db9452a9 1314
068aaea8 1315
168e428f 1316
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1317.section "Router preconditions" "SECTrouprecon"
1318.cindex "router preconditions" "order of processing"
1319.cindex "preconditions" "order of processing"
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1320The preconditions that are tested for each router are listed below, in the
1321order in which they are tested. The individual configuration options are
9b371988 1322described in more detail in chapter &<<CHAProutergeneric>>&.
168e428f 1323
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1324.ilist
1325The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
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1326the local parts handled by the router may or must have certain prefixes and/or
1327suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1328skipped. These conditions are tested first. When an affix is present, it is
1329removed from the local part before further processing, including the evaluation
1330of any other conditions.
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1331.next
1332Routers can be designated for use only when not verifying an address, that is,
168e428f 1333only when routing it for delivery (or testing its delivery routing). If the
9b371988 1334&%verify%& option is set false, the router is skipped when Exim is verifying an
168e428f 1335address.
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1336Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1337&%verify_recipient%&, which independently control the use of the router for
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1338sender and recipient verification. You can set these options directly if
1339you want a router to be used for only one type of verification.
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1340.next
1341If the &%address_test%& option is set false, the router is skipped when Exim is
1342run with the &%-bt%& option to test an address routing. This can be helpful
1343when the first router sends all new messages to a scanner of some sort; it
1344makes it possible to use &%-bt%& to test subsequent delivery routing without
1345having to simulate the effect of the scanner.
1346.next
1347Routers can be designated for use only when verifying an address, as
1348opposed to routing it for delivery. The &%verify_only%& option controls this.
1349.next
1350Individual routers can be explicitly skipped when running the routers to
1351check an address given in the SMTP EXPN command (see the &%expn%& option).
1352.next
1353If the &%domains%& option is set, the domain of the address must be in the set
068aaea8 1354of domains that it defines.
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1355.next
1356.cindex "&$local_part_prefix$&"
1357.cindex "&$local_part$&"
1358.cindex "&$local_part_suffix$&"
1359If the &%local_parts%& option is set, the local part of the address must be in
1360the set of local parts that it defines. If &%local_part_prefix%& or
1361&%local_part_suffix%& is in use, the prefix or suffix is removed from the local
168e428f 1362part before this check. If you want to do precondition tests on local parts
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1363that include affixes, you can do so by using a &%condition%& option (see below)
1364that uses the variables &$local_part$&, &$local_part_prefix$&, and
1365&$local_part_suffix$& as necessary.
1366.next
1367.cindex "&$local_user_uid$&"
1368.cindex "&$local_user_gid$&"
1369.cindex "&$home$&"
1370If the &%check_local_user%& option is set, the local part must be the name of
068aaea8 1371an account on the local host. If this check succeeds, the uid and gid of the
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1372local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1373user's home directory is placed in &$home$&; these values can be used in the
1374remaining preconditions.
1375.next
1376If the &%router_home_directory%& option is set, it is expanded at this point,
1377because it overrides the value of &$home$&. If this expansion were left till
1378later, the value of &$home$& as set by &%check_local_user%& would be used in
1379subsequent tests. Having two different values of &$home$& in the same router
168e428f 1380could lead to confusion.
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1381.next
1382If the &%senders%& option is set, the envelope sender address must be in the
1383set of addresses that it defines.
1384.next
1385If the &%require_files%& option is set, the existence or non-existence of
168e428f 1386specified files is tested.
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1387.next
1388.cindex "customizing" "precondition"
1389If the &%condition%& option is set, it is evaluated and tested. This option
1390uses an expanded string to allow you to set up your own custom preconditions.
1391Expanded strings are described in chapter &<<CHAPexpand>>&.
1392.endlist
168e428f 1393
168e428f 1394
9b371988
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1395Note that &%require_files%& comes near the end of the list, so you cannot use
1396it to check for the existence of a file in which to lookup up a domain, local
168e428f 1397part, or sender. However, as these options are all expanded, you can use the
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1398&%exists%& expansion condition to make such tests within each condition. The
1399&%require_files%& option is intended for checking files that the router may be
168e428f 1400going to use internally, or which are needed by a specific transport (for
9b371988 1401example, &_.procmailrc_&).
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1402
1403
1404
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1405.section "Delivery in detail"
1406.cindex "delivery" "in detail"
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1407When a message is to be delivered, the sequence of events is as follows:
1408
9b371988
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1409.ilist
1410If a system-wide filter file is specified, the message is passed to it. The
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1411filter may add recipients to the message, replace the recipients, discard the
1412message, cause a new message to be generated, or cause the message delivery to
1413fail. The format of the system filter file is the same as for Exim user filter
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1414files, described in the separate document entitled &'Exim's interfaces to mail
1415filtering'&.
1416.cindex "Sieve filter" "not available for system filter"
1417(&*Note*&: Sieve cannot be used for system filter files.)
1418
1419Some additional features are available in system filters &-- see chapter
1420&<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
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1421filter only once per delivery attempt, however many recipients it has. However,
1422if there are several delivery attempts because one or more addresses could not
1423be immediately delivered, the system filter is run each time. The filter
9b371988 1424condition &%first_delivery%& can be used to detect the first run of the system
168e428f 1425filter.
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1426.next
1427Each recipient address is offered to each configured router in turn, subject to
1428its preconditions, until one is able to handle it. If no router can handle the
1429address, that is, if they all decline, the address is failed. Because routers
1430can be targeted at particular domains, several locally handled domains can be
1431processed entirely independently of each other.
1432.next
1433.cindex "routing" "loops in"
1434.cindex "loop" "while routing"
1435A router that accepts an address may assign it to a local or a remote
1436transport. However, the transport is not run at this time. Instead, the address
1437is placed on a list for the particular transport, which will be run later.
068aaea8
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1438Alternatively, the router may generate one or more new addresses (typically
1439from alias, forward, or filter files). New addresses are fed back into this
1440process from the top, but in order to avoid loops, a router ignores any address
1441which has an identically-named ancestor that was processed by itself.
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1442.next
1443When all the routing has been done, addresses that have been successfully
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1444handled are passed to their assigned transports. When local transports are
1445doing real local deliveries, they handle only one address at a time, but if a
1446local transport is being used as a pseudo-remote transport (for example, to
1447collect batched SMTP messages for transmission by some other means) multiple
1448addresses can be handled. Remote transports can always handle more than one
1449address at a time, but can be configured not to do so, or to restrict multiple
1450addresses to the same domain.
9b371988
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1451.next
1452Each local delivery to a file or a pipe runs in a separate process under a
168e428f
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1453non-privileged uid, and these deliveries are run one at a time. Remote
1454deliveries also run in separate processes, normally under a uid that is private
9b371988 1455to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
168e428f 1456run in parallel. The maximum number of simultaneous remote deliveries for any
9b371988 1457one message is set by the &%remote_max_parallel%& option.
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1458The order in which deliveries are done is not defined, except that all local
1459deliveries happen before any remote deliveries.
9b371988
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1460.next
1461.cindex "queue runner"
168e428f
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1462When it encounters a local delivery during a queue run, Exim checks its retry
1463database to see if there has been a previous temporary delivery failure for the
1464address before running the local transport. If there was a previous failure,
1465Exim does not attempt a new delivery until the retry time for the address is
1466reached. However, this happens only for delivery attempts that are part of a
1467queue run. Local deliveries are always attempted when delivery immediately
1468follows message reception, even if retry times are set for them. This makes for
1469better behaviour if one particular message is causing problems (for example,
1470causing quota overflow, or provoking an error in a filter file).
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1471.next
1472.cindex "delivery" "retry in remote transports"
168e428f
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1473Remote transports do their own retry handling, since an address may be
1474deliverable to one of a number of hosts, each of which may have a different
1475retry time. If there have been previous temporary failures and no host has
1476reached its retry time, no delivery is attempted, whether in a queue run or
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1477not. See chapter &<<CHAPretry>>& for details of retry strategies.
1478.next
1479If there were any permanent errors, a bounce message is returned to an
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1480appropriate address (the sender in the common case), with details of the error
1481for each failing address. Exim can be configured to send copies of bounce
1482messages to other addresses.
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1483.next
1484.cindex "delivery" "deferral"
168e428f
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1485If one or more addresses suffered a temporary failure, the message is left on
1486the queue, to be tried again later. Delivery of these addresses is said to be
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1487&'deferred'&.
1488.next
1489When all the recipient addresses have either been delivered or bounced,
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1490handling of the message is complete. The spool files and message log are
1491deleted, though the message log can optionally be preserved if required.
9b371988 1492.endlist
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1493
1494
1495
1496
9b371988
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1497.section "Retry mechanism"
1498.cindex "delivery" "retry mechanism"
1499.cindex "retry" "description of mechanism"
1500.cindex "queue runner"
168e428f
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1501Exim's mechanism for retrying messages that fail to get delivered at the first
1502attempt is the queue runner process. You must either run an Exim daemon that
9b371988
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1503uses the &%-q%& option with a time interval to start queue runners at regular
1504intervals, or use some other means (such as &'cron'&) to start them. If you do
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1505not arrange for queue runners to be run, messages that fail temporarily at the
1506first attempt will remain on your queue for ever. A queue runner process works
068aaea8 1507its way through the queue, one message at a time, trying each delivery that has
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1508passed its retry time.
1509You can run several queue runners at once.
1510
1511Exim uses a set of configured rules to determine when next to retry the failing
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1512address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1513should give up trying to deliver to the address, at which point it generates a
1514bounce message. If no retry rules are set for a particular host, address, and
1515error combination, no retries are attempted, and temporary errors are treated
1516as permanent.
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1517
1518
1519
9b371988
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1520.section "Temporary delivery failure"
1521.cindex "delivery" "temporary failure"
168e428f
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1522There are many reasons why a message may not be immediately deliverable to a
1523particular address. Failure to connect to a remote machine (because it, or the
1524connection to it, is down) is one of the most common. Temporary failures may be
1525detected during routing as well as during the transport stage of delivery.
1526Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1527is on a file system where the user is over quota. Exim can be configured to
1528impose its own quotas on local mailboxes; where system quotas are set they will
1529also apply.
1530
1531If a host is unreachable for a period of time, a number of messages may be
1532waiting for it by the time it recovers, and sending them in a single SMTP
1533connection is clearly beneficial. Whenever a delivery to a remote host is
1534deferred,
1535
9b371988 1536.cindex "hints database"
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1537Exim makes a note in its hints database, and whenever a successful
1538SMTP delivery has happened, it looks to see if any other messages are waiting
1539for the same host. If any are found, they are sent over the same SMTP
1540connection, subject to a configuration limit as to the maximum number in any
1541one connection.
1542
1543
1544
1545
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1546.section "Permanent delivery failure"
1547.cindex "delivery" "permanent failure"
1548.cindex "bounce message" "when generated"
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1549When a message cannot be delivered to some or all of its intended recipients, a
1550bounce message is generated. Temporary delivery failures turn into permanent
1551errors when their timeout expires. All the addresses that fail in a given
1552delivery attempt are listed in a single message. If the original message has
1553many recipients, it is possible for some addresses to fail in one delivery
1554attempt and others to fail subsequently, giving rise to more than one bounce
1555message. The wording of bounce messages can be customized by the administrator.
9b371988 1556See chapter &<<CHAPemsgcust>>& for details.
168e428f 1557
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1558.cindex "&'X-Failed-Recipients:'& header line"
1559Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
168e428f
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1560failed addresses, for the benefit of programs that try to analyse such messages
1561automatically.
1562
9b371988 1563.cindex "bounce message" "recipient of"
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1564A bounce message is normally sent to the sender of the original message, as
1565obtained from the message's envelope. For incoming SMTP messages, this is the
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1566address given in the MAIL command. However, when an address is expanded via a
1567forward or alias file, an alternative address can be specified for delivery
1568failures of the generated addresses. For a mailing list expansion (see section
1569&<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1570of the list.
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1571
1572
1573
9b371988
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1574.section "Failures to deliver bounce messages"
1575.cindex "bounce message" "failure to deliver"
168e428f
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1576If a bounce message (either locally generated or received from a remote host)
1577itself suffers a permanent delivery failure, the message is left on the queue,
1578but it is frozen, awaiting the attention of an administrator. There are options
068aaea8 1579that can be used to make Exim discard such failed messages, or to keep them
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1580for only a short time (see &%timeout_frozen_after%& and
1581&%ignore_bounce_errors_after%&).
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1582
1583
1584
1585
1586
9b371988
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1587. ////////////////////////////////////////////////////////////////////////////
1588. ////////////////////////////////////////////////////////////////////////////
168e428f 1589
9b371988 1590.chapter "Building and installing Exim"
4f578862 1591.scindex IIDbuex "building Exim"
168e428f 1592
9b371988 1593.section "Unpacking"
168e428f
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1594Exim is distributed as a gzipped or bzipped tar file which, when upacked,
1595creates a directory with the name of the current release (for example,
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1596&_exim-&version;_&) into which the following files are placed:
1597
1598.table2 140pt
1599.row &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1600.row &_CHANGES_& "contains a reference to where changes are documented"
1601.row &_LICENCE_& "the GNU General Public Licence"
1602.row &_Makefile_& "top-level make file"
1603.row &_NOTICE_& "conditions for the use of Exim"
1604.row &_README_& "list of files, directories and simple build &&&
1605 instructions"
1606.endtable
1607
1608Other files whose names begin with &_README_& may also be present. The
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1609following subdirectories are created:
1610
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1611.table2 140pt
1612.row &_Local_& "an empty directory for local configuration files"
1613.row &_OS_& "OS-specific files"
1614.row &_doc_& "documentation files"
1615.row &_exim_monitor_& "source files for the Exim monitor"
1616.row &_scripts_& "scripts used in the build process"
1617.row &_src_& "remaining source files"
1618.row &_util_& "independent utilities"
1619.endtable
1620
1621The main utility programs are contained in the &_src_& directory, and are built
1622with the Exim binary. The &_util_& directory contains a few optional scripts
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1623that may be useful to some sites.
1624
1625
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1626.section "Multiple machine architectures and operating systems"
1627.cindex "building Exim" "multiple OS/architectures"
168e428f
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1628The building process for Exim is arranged to make it easy to build binaries for
1629a number of different architectures and operating systems from the same set of
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1630source files. Compilation does not take place in the &_src_& directory.
1631Instead, a &'build directory'& is created for each architecture and operating
1632system.
1633.cindex "symbolic link" "to build directory"
168e428f 1634Symbolic links to the sources are installed in this directory, which is where
9b371988
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1635the actual building takes place. In most cases, Exim can discover the machine
1636architecture and operating system for itself, but the defaults can be
1637overridden if necessary.
168e428f 1638
168e428f 1639
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1640.section "DBM libraries" "SECTdb"
1641.cindex "DBM libraries" "discussion of"
1642.cindex "hints database" "DBM files used for"
168e428f
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1643Even if you do not use any DBM files in your configuration, Exim still needs a
1644DBM library in order to operate, because it uses indexed files for its hints
1645databases. Unfortunately, there are a number of DBM libraries in existence, and
1646different operating systems often have different ones installed.
1647
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1648.cindex "Solaris" "DBM library for"
1649.cindex "IRIX" "DBM library for"
1650.cindex "BSD" "DBM library for"
1651.cindex "Linux" "DBM library for"
168e428f
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1652If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1653Linux distribution, the DBM configuration should happen automatically, and you
1654may be able to ignore this section. Otherwise, you may have to learn more than
1655you would like about DBM libraries from what follows.
1656
9b371988 1657.cindex "&'ndbm'& DBM library"
168e428f 1658Licensed versions of Unix normally contain a library of DBM functions operating
9b371988 1659via the &'ndbm'& interface, and this is what Exim expects by default. Free
168e428f
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1660versions of Unix seem to vary in what they contain as standard. In particular,
1661some early versions of Linux have no default DBM library, and different
1662distributors have chosen to bundle different libraries with their packaged
1663versions. However, the more recent releases seem to have standardised on the
1664Berkeley DB library.
1665
1666Different DBM libraries have different conventions for naming the files they
9b371988 1667use. When a program opens a file called &_dbmfile_&, there are several
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1668possibilities:
1669
9b371988
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1670.olist
1671A traditional &'ndbm'& implementation, such as that supplied as part of
1672Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1673.next
1674.cindex "&'gdbm'& DBM library"
1675The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
168e428f 1676compatibility interface it makes two different hard links to it with names
9b371988 1677&_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
168e428f 1678file name is used unmodified.
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1679.next
1680.cindex "Berkeley DB library"
1681The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1682operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1683programmer exactly the same as the traditional &'ndbm'& implementation.
1684.next
1685If the Berkeley package is used in its native mode, it operates on a single
1686file called &_dbmfile_&; the programmer's interface is somewhat different to
1687the traditional &'ndbm'& interface.
1688.next
1689To complicate things further, there are several very different versions of the
168e428f 1690Berkeley DB package. Version 1.85 was stable for a very long time, releases
9b371988
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16912.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1692numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
168e428f 1693versions of Berkeley DB can be obtained from
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1694&url(http://www.sleepycat.com/).
1695.next
1696.cindex "&'tdb'& DBM library"
1697Yet another DBM library, called &'tdb'&, is available from
1698&url(http://download.sourceforge.net/tdb). It has its own interface, and also
1699operates on a single file.
1700.endlist
1701
1702.cindex "USE_DB"
1703.cindex "DBM libraries" "configuration for building"
168e428f
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1704Exim and its utilities can be compiled to use any of these interfaces. In order
1705to use any version of the Berkeley DB package in native mode, you must set
1706USE_DB in an appropriate configuration file (typically
9b371988
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1707&_Local/Makefile_&). For example:
1708.code
1709USE_DB=yes
1710.endd
168e428f
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1711Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1712error is diagnosed if you set more than one of these.
1713
1714At the lowest level, the build-time configuration sets none of these options,
1715thereby assuming an interface of type (1). However, some operating system
1716configuration files (for example, those for the BSD operating systems and
1717Linux) assume type (4) by setting USE_DB as their default, and the
1718configuration files for Cygwin set USE_GDBM. Anything you set in
9b371988 1719&_Local/Makefile_&, however, overrides these system defaults.
168e428f
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1720
1721As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1722necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1723in one of these lines:
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1724.code
1725DBMLIB = -ldb
1726DBMLIB = -ltdb
1727.endd
168e428f
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1728Settings like that will work if the DBM library is installed in the standard
1729place. Sometimes it is not, and the library's header file may also not be in
1730the default path. You may need to set INCLUDE to specify where the header
1731file is, and to specify the path to the library more fully in DBMLIB, as in
1732this example:
9b371988
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1733.code
1734INCLUDE=-I/usr/local/include/db-4.1
1735DBMLIB=/usr/local/lib/db-4.1/libdb.a
1736.endd
168e428f 1737There is further detailed discussion about the various DBM libraries in the
9b371988 1738file &_doc/dbm.discuss.txt_& in the Exim distribution.
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1739
1740
1741
9b371988
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1742.section "Pre-building configuration"
1743.cindex "building Exim" "pre-building configuration"
1744.cindex "configuration for building Exim"
1745.cindex "&_Local/Makefile_&"
1746.cindex "&_src/EDITME_&"
168e428f
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1747Before building Exim, a local configuration file that specifies options
1748independent of any operating system has to be created with the name
9b371988
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1749&_Local/Makefile_&. A template for this file is supplied as the file
1750&_src/EDITME_&, and it contains full descriptions of all the option settings
168e428f
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1751therein. These descriptions are therefore not repeated here. If you are
1752building Exim for the first time, the simplest thing to do is to copy
9b371988 1753&_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
168e428f
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1754
1755There are three settings that you must supply, because Exim will not build
1756without them. They are the location of the run time configuration file
1757(CONFIGURE_FILE), the directory in which Exim binaries will be installed
1758(BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1759maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1760a colon-separated list of file names; Exim uses the first of them that exists.
1761
1762There are a few other parameters that can be specified either at build time or
1763at run time, to enable the same binary to be used on a number of different
1764machines. However, if the locations of Exim's spool directory and log file
1765directory (if not within the spool directory) are fixed, it is recommended that
9b371988 1766you specify them in &_Local/Makefile_& instead of at run time, so that errors
168e428f
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1767detected early in Exim's execution (such as a malformed configuration file) can
1768be logged.
1769
9b371988 1770.cindex "content scanning" "specifying at build time"
068aaea8 1771Exim's interfaces for calling virus and spam scanning software directly from
168e428f
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1772access control lists are not compiled by default. If you want to include these
1773facilities, you need to set
9b371988
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1774.code
1775WITH_CONTENT_SCAN=yes
1776.endd
1777in your &_Local/Makefile_&. For details of the facilities themselves, see
1778chapter &<<CHAPexiscan>>&.
168e428f
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1779
1780
9b371988 1781.cindex "&_Local/eximon.conf_&"
3cb1b51e 1782.cindex "&_exim_monitor/EDITME_&"
168e428f 1783If you are going to build the Exim monitor, a similar configuration process is
9b371988
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1784required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1785your installation and saved under the name &_Local/eximon.conf_&. If you are
1786happy with the default settings described in &_exim_monitor/EDITME_&,
1787&_Local/eximon.conf_& can be empty, but it must exist.
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1788
1789This is all the configuration that is needed in straightforward cases for known
1790operating systems. However, the building process is set up so that it is easy
1791to override options that are set by default or by operating-system-specific
1792configuration files, for example to change the name of the C compiler, which
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1793defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1794do this.
168e428f
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1795
1796
1797
9b371988
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1798.section "Support for iconv()"
1799.cindex "&[iconv()]& support"
1800.cindex "RFC 2047"
168e428f
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1801The contents of header lines in messages may be encoded according to the rules
1802described RFC 2047. This makes it possible to transmit characters that are not
1803in the ASCII character set, and to label them as being in a particular
9b371988 1804character set. When Exim is inspecting header lines by means of the &%$h_%&
168e428f
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1805mechanism, it decodes them, and translates them into a specified character set
1806(default ISO-8859-1). The translation is possible only if the operating system
9b371988
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1807supports the &[iconv()]& function.
1808
1809However, some of the operating systems that supply &[iconv()]& do not support
1810very many conversions. The GNU &%libiconv%& library (available from
1811&url(http://www.gnu.org/software/libiconv/)) can be installed on such
1812systems to remedy this deficiency, as well as on systems that do not supply
1813&[iconv()]& at all. After installing &%libiconv%&, you should add
1814.code
1815HAVE_ICONV=yes
1816.endd
1817to your &_Local/Makefile_& and rebuild Exim.
1818
1819
1820
1821.section "Including TLS/SSL encryption support" "SECTinctlsssl"
1822.cindex "TLS" "including support for TLS"
1823.cindex "encryption" "including support for"
1824.cindex "SUPPORT_TLS"
1825.cindex "OpenSSL" "building Exim with"
1826.cindex "GnuTLS" "building Exim with"
168e428f
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1827Exim can be built to support encrypted SMTP connections, using the STARTTLS
1828command as per RFC 2487. It can also support legacy clients that expect to
1829start a TLS session immediately on connection to a non-standard port (see the
9b371988 1830&%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
168e428f
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1831line option).
1832
1833If you want to build Exim with TLS support, you must first install either the
1834OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1835implementing SSL.
1836
1837If OpenSSL is installed, you should set
9b371988
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1838.code
1839SUPPORT_TLS=yes
1840TLS_LIBS=-lssl -lcrypto
1841.endd
1842in &_Local/Makefile_&. You may also need to specify the locations of the
168e428f 1843OpenSSL library and include files. For example:
9b371988
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1844.code
1845SUPPORT_TLS=yes
1846TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1847TLS_INCLUDE=-I/usr/local/openssl/include/
1848.endd
1849.cindex "USE_GNUTLS"
168e428f 1850If GnuTLS is installed, you should set
9b371988
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1851.code
1852SUPPORT_TLS=yes
1853USE_GNUTLS=yes
1854TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1855.endd
1856in &_Local/Makefile_&, and again you may need to specify the locations of the
168e428f 1857library and include files. For example:
9b371988
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1858.code
1859SUPPORT_TLS=yes
1860USE_GNUTLS=yes
1861TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1862TLS_INCLUDE=-I/usr/gnu/include
1863.endd
168e428f 1864You do not need to set TLS_INCLUDE if the relevant directory is already
9b371988
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1865specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1866given in chapter &<<CHAPTLS>>&.
168e428f
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1867
1868
1869
1870
9b371988
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1871.section "Use of tcpwrappers"
1872.cindex "tcpwrappers" "building Exim to support"
1873.cindex "USE_TCP_WRAPPERS"
1874Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1875SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
168e428f 1876alternative to Exim's own checking facilities for installations that are
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1877already making use of &'tcpwrappers'& for other purposes. To do this, you
1878should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1879&_tcpd.h_& to be available at compile time, and also ensure that the library
1880&_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1881EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1882you might have
1883.code
1884USE_TCP_WRAPPERS=yes
1885CFLAGS=-O -I/usr/local/include
1886EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1887.endd
1888in &_Local/Makefile_&. The name to use in the &'tcpwrappers'& control files is
1889&"exim"&. For example, the line
1890.code
1891exim : LOCAL 192.168.1. .friendly.domain.example
1892.endd
1893in your &_/etc/hosts.allow_& file allows connections from the local host, from
1894the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&.
1895All other connections are denied. Consult the &'tcpwrappers'& documentation for
168e428f
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1896further details.
1897
1898
1899
9b371988
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1900.section "Including support for IPv6"
1901.cindex "IPv6" "including support for"
168e428f 1902Exim contains code for use on systems that have IPv6 support. Setting
9b371988 1903&`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
168e428f
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1904it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1905where the IPv6 support is not fully integrated into the normal include and
1906library files.
1907
1908Two different types of DNS record for handling IPv6 addresses have been
1909defined. AAAA records (analagous to A records for IPv4) are in use, and are
1910currently seen as the mainstream. Another record type called A6 was proposed
1911as better than AAAA because it had more flexibility. However, it was felt to be
9b371988 1912over-complex, and its status was reduced to &"experimental"&. It is not known
168e428f 1913if anyone is actually using A6 records. Exim has support for A6 records, but
9b371988 1914this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
168e428f
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1915support has not been tested for some time.
1916
1917
1918
9b371988
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1919.section "The building process"
1920.cindex "build directory"
1921Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
1922created, run &'make'& at the top level. It determines the architecture and
168e428f
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1923operating system types, and creates a build directory if one does not exist.
1924For example, on a Sun system running Solaris 8, the directory
9b371988
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1925&_build-SunOS5-5.8-sparc_& is created.
1926.cindex "symbolic link" "to source files"
168e428f
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1927Symbolic links to relevant source files are installed in the build directory.
1928
9b371988 1929&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
168e428f
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1930building process fails if it is set.
1931
9b371988 1932If this is the first time &'make'& has been run, it calls a script that builds
168e428f 1933a make file inside the build directory, using the configuration files from the
9b371988
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1934&_Local_& directory. The new make file is then passed to another instance of
1935&'make'&. This does the real work, building a number of utility scripts, and
168e428f 1936then compiling and linking the binaries for the Exim monitor (if configured), a
9b371988
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1937number of utility programs, and finally Exim itself. The command &`make
1938makefile`& can be used to force a rebuild of the make file in the build
168e428f
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1939directory, should this ever be necessary.
1940
1941If you have problems building Exim, check for any comments there may be in the
9b371988 1942&_README_& file concerning your operating system, and also take a look at the
168e428f
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1943FAQ, where some common problems are covered.
1944
1945
1946
9b371988 1947.section 'Output from &"make"&'
9b371988 1948The output produced by the &'make'& process for compile lines is often very
068aaea8
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1949unreadable, because these lines can be very long. For this reason, the normal
1950output is suppressed by default, and instead output similar to that which
1951appears when compiling the 2.6 Linux kernel is generated: just a short line for
1952each module that is being compiled or linked. However, it is still possible to
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1953get the full output, by calling &'make'& like this:
1954.code
1955FULLECHO='' make -e
1956.endd
1957The value of FULLECHO defaults to &"@"&, the flag character that suppresses
1958command reflection in &'make'&. When you ask for the full output, it is
3cb1b51e 1959given in addition to the short output.
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1960
1961
1962
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1963.section "Overriding build-time options for Exim" "SECToverride"
1964.cindex "build-time options" "overriding"
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1965The main make file that is created at the beginning of the building process
1966consists of the concatenation of a number of files which set configuration
9b371988 1967values, followed by a fixed set of &'make'& instructions. If a value is set
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1968more than once, the last setting overrides any previous ones. This provides a
1969convenient way of overriding defaults. The files that are concatenated are, in
1970order:
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1971.display
1972&_OS/Makefile-Default_&
1973&_OS/Makefile-_&<&'ostype'&>
1974&_Local/Makefile_&
1975&_Local/Makefile-_&<&'ostype'&>
1976&_Local/Makefile-_&<&'archtype'&>
1977&_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
1978&_OS/Makefile-Base_&
1979.endd
1980.cindex "&_Local/Makefile_&"
1981.cindex "building Exim" "operating system type"
1982.cindex "building Exim" "architecture type"
1983where <&'ostype'&> is the operating system type and <&'archtype'&> is the
1984architecture type. &_Local/Makefile_& is required to exist, and the building
1985process fails if it is absent. The other three &_Local_& files are optional,
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1986and are often not needed.
1987
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1988The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
1989called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
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1990the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
1991values are used, thereby providing a means of forcing particular settings.
9b371988 1992Otherwise, the scripts try to get values from the &%uname%& command. If this
168e428f 1993fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
9b371988 1994of &'ad hoc'& transformations are then applied, to produce the standard names
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1995that Exim expects. You can run these scripts directly from the shell in order
1996to find out what values are being used on your system.
1997
1998
9b371988 1999&_OS/Makefile-Default_& contains comments about the variables that are set
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2000therein. Some (but not all) are mentioned below. If there is something that
2001needs changing, review the contents of this file and the contents of the make
9b371988 2002file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
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2003default values are.
2004
2005
9b371988
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2006.cindex "building Exim" "overriding default settings"
2007If you need to change any of the values that are set in &_OS/Makefile-Default_&
2008or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
168e428f 2009need to change the original files. Instead, you should make the changes by
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2010putting the new values in an appropriate &_Local_& file. For example,
2011.cindex "Tru64-Unix build-time settings"
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2012when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2013formerly DEC-OSF1) operating system, it is necessary to specify that the C
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2014compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2015called with the option &%-std1%&, to make it recognize some of the features of
168e428f 2016Standard C that Exim uses. (Most other compilers recognize Standard C by
9b371988 2017default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
168e428f 2018containing the lines
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2019.code
2020CC=cc
2021CFLAGS=-std1
2022.endd
168e428f 2023If you are compiling for just one operating system, it may be easier to put
9b371988 2024these lines directly into &_Local/Makefile_&.
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2025
2026Keeping all your local configuration settings separate from the distributed
2027files makes it easy to transfer them to new versions of Exim simply by copying
9b371988 2028the contents of the &_Local_& directory.
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2029
2030
9b371988
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2031.cindex "NIS lookup type" "including support for"
2032.cindex "NIS+ lookup type" "including support for"
2033.cindex "LDAP" "including support for"
2034.cindex "lookup" "inclusion in binary"
168e428f
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2035Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2036lookup, but not all systems have these components installed, so the default is
2037not to include the relevant code in the binary. All the different kinds of file
2038and database lookup that Exim supports are implemented as separate code modules
2039which are included only if the relevant compile-time options are set. In the
9b371988
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2040case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2041.code
2042LOOKUP_LDAP=yes
2043LOOKUP_NIS=yes
2044LOOKUP_NISPLUS=yes
2045.endd
168e428f 2046and similar settings apply to the other lookup types. They are all listed in
9b371988 2047&_src/EDITME_&. In many cases the relevant include files and interface
168e428f 2048libraries need to be installed before compiling Exim.
9b371988 2049.cindex "cdb" "including support for"
068aaea8
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2050However, there are some optional lookup types (such as cdb) for which
2051the code is entirely contained within Exim, and no external include
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2052files or libraries are required. When a lookup type is not included in the
2053binary, attempts to configure Exim to use it cause run time configuration
2054errors.
2055
9b371988 2056.cindex "Perl" "including support for"
168e428f
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2057Exim can be linked with an embedded Perl interpreter, allowing Perl
2058subroutines to be called during string expansion. To enable this facility,
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2059.code
2060EXIM_PERL=perl.o
2061.endd
2062must be defined in &_Local/Makefile_&. Details of this facility are given in
2063chapter &<<CHAPperl>>&.
168e428f 2064
9b371988 2065.cindex "X11 libraries" "location of"
168e428f 2066The location of the X11 libraries is something that varies a lot between
068aaea8 2067operating systems, and there may be different versions of X11 to cope
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2068with. Exim itself makes no use of X11, but if you are compiling the Exim
2069monitor, the X11 libraries must be available.
9b371988
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2070The following three variables are set in &_OS/Makefile-Default_&:
2071.code
2072X11=/usr/X11R6
2073XINCLUDE=-I$(X11)/include
2074XLFLAGS=-L$(X11)/lib
2075.endd
168e428f 2076These are overridden in some of the operating-system configuration files. For
9b371988
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2077example, in &_OS/Makefile-SunOS5_& there is
2078.code
2079X11=/usr/openwin
2080XINCLUDE=-I$(X11)/include
2081XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2082.endd
168e428f
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2083If you need to override the default setting for your operating system, place a
2084definition of all three of these variables into your
9b371988 2085&_Local/Makefile-<ostype>_& file.
168e428f 2086
9b371988 2087.cindex "EXTRALIBS"
168e428f
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2088If you need to add any extra libraries to the link steps, these can be put in a
2089variable called EXTRALIBS, which appears in all the link commands, but by
2090default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2091command for linking the main Exim binary, and not for any associated utilities.
2092
9b371988 2093.cindex "DBM libraries" "configuration for building"
168e428f 2094There is also DBMLIB, which appears in the link commands for binaries that
9b371988 2095use DBM functions (see also section &<<SECTdb>>&). Finally, there is
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2096EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2097binary, and which can be used, for example, to include additional X11
2098libraries.
2099
9b371988 2100.cindex "configuration file" "editing"
168e428f
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2101The make file copes with rebuilding Exim correctly if any of the configuration
2102files are edited. However, if an optional configuration file is deleted, it is
9b371988
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2103necessary to touch the associated non-optional file (that is,
2104&_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
168e428f
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2105
2106
9b371988
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2107.section "OS-specific header files"
2108.cindex "&_os.h_&"
2109.cindex "building Exim" "OS-specific C header files"
2110The &_OS_& directory contains a number of files with names of the form
2111&_os.h-<ostype>_&. These are system-specific C header files that should not
168e428f 2112normally need to be changed. There is a list of macro settings that are
9b371988 2113recognized in the file &_OS/os.configuring_&, which should be consulted if you
168e428f
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2114are porting Exim to a new operating system.
2115
2116
2117
9b371988
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2118.section "Overriding build-time options for the monitor"
2119.cindex "building Eximon" "overriding default options"
168e428f
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2120A similar process is used for overriding things when building the Exim monitor,
2121where the files that are involved are
9b371988
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2122.display
2123&_OS/eximon.conf-Default_&
2124&_OS/eximon.conf-_&<&'ostype'&>
2125&_Local/eximon.conf_&
2126&_Local/eximon.conf-_&<&'ostype'&>
2127&_Local/eximon.conf-_&<&'archtype'&>
2128&_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2129.endd
2130.cindex "&_Local/eximon.conf_&"
168e428f 2131As with Exim itself, the final three files need not exist, and in this case the
9b371988
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2132&_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2133&_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
168e428f
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2134variables of the same name, preceded by EXIMON_. For example, setting
2135EXIMON_LOG_DEPTH in the environment overrides the value of
2136LOG_DEPTH at run time.
4f578862 2137.ecindex IIDbuex
168e428f
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2138
2139
9b371988
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2140.section "Installing Exim binaries and scripts"
2141.cindex "installing Exim"
2142.cindex "BIN_DIRECTORY"
2143The command &`make install`& runs the &(exim_install)& script with no
2144arguments. The script copies binaries and utility scripts into the directory
2145whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2146.cindex "setuid" "installing Exim with"
068aaea8
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2147The install script copies files only if they are newer than the files they are
2148going to replace. The Exim binary is required to be owned by root and have the
9b371988
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2149&'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2150install`& as root so that it can set up the Exim binary in this way. However, in
068aaea8
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2151some special situations (for example, if a host is doing no local deliveries)
2152it may be possible to run Exim without making the binary setuid root (see
9b371988 2153chapter &<<CHAPsecurity>>& for details).
168e428f 2154
9b371988 2155.cindex "CONFIGURE_FILE"
168e428f 2156Exim's run time configuration file is named by the CONFIGURE_FILE setting
9b371988
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2157in &_Local/Makefile_&. If this names a single file, and the file does not
2158exist, the default configuration file &_src/configure.default_& is copied there
168e428f
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2159by the installation script. If a run time configuration file already exists, it
2160is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2161alternative files, no default is installed.
2162
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2163.cindex "system aliases file"
2164.cindex "&_/etc/aliases_&"
168e428f
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2165One change is made to the default configuration file when it is installed: the
2166default configuration contains a router that references a system aliases file.
2167The path to this file is set to the value specified by
9b371988 2168SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
168e428f
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2169If the system aliases file does not exist, the installation script creates it,
2170and outputs a comment to the user.
2171
2172The created file contains no aliases, but it does contain comments about the
2173aliases a site should normally have. Mail aliases have traditionally been
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2174kept in &_/etc/aliases_&. However, some operating systems are now using
2175&_/etc/mail/aliases_&. You should check if yours is one of these, and change
168e428f
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2176Exim's configuration if necessary.
2177
2178The default configuration uses the local host's name as the only local domain,
9b371988
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2179and is set up to do local deliveries into the shared directory &_/var/mail_&,
2180running as the local user. System aliases and &_.forward_& files in users' home
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2181directories are supported, but no NIS or NIS+ support is configured. Domains
2182other than the name of the local host are routed using the DNS, with delivery
2183over SMTP.
2184
168e428f
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2185It is possible to install Exim for special purposes (such as building a binary
2186distribution) in a private part of the file system. You can do this by a
2187command such as
9b371988
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2188.code
2189make DESTDIR=/some/directory/ install
2190.endd
168e428f
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2191This has the effect of pre-pending the specified directory to all the file
2192paths, except the name of the system aliases file that appears in the default
9b371988 2193configuration. (If a default alias file is created, its name &'is'& modified.)
168e428f
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2194For backwards compatibility, ROOT is used if DESTDIR is not set,
2195but this usage is deprecated.
2196
9b371988
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2197.cindex "installing Exim" "what is not installed"
2198Running &'make install'& does not copy the Exim 4 conversion script
2199&'convert4r4'&, or the &'pcretest'& test program. You will probably run the
168e428f 2200first of these only once (if you are upgrading from Exim 3), and the second
9b371988 2201isn't really part of Exim. None of the documentation files in the &_doc_&
168e428f 2202directory are copied, except for the info files when you have set
9b371988 2203INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
168e428f 2204
9b371988 2205For the utility programs, old versions are renamed by adding the suffix &_.O_&
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2206to their names. The Exim binary itself, however, is handled differently. It is
2207installed under a name that includes the version number and the compile number,
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2208for example &_exim-&version;-1_&. The script then arranges for a symbolic link
2209called &_exim_& to point to the binary. If you are updating a previous version
2210of Exim, the script takes care to ensure that the name &_exim_& is never absent
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2211from the directory (as seen by other processes).
2212
9b371988
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2213.cindex "installing Exim" "testing the script"
2214If you want to see what the &'make install'& will do before running it for
2215real, you can pass the &%-n%& option to the installation script by this
2216command:
2217.code
2218make INSTALL_ARG=-n install
2219.endd
168e428f
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2220The contents of the variable INSTALL_ARG are passed to the installation
2221script. You do not need to be root to run this test. Alternatively, you can run
2222the installation script directly, but this must be from within the build
2223directory. For example, from the top-level Exim directory you could use this
2224command:
9b371988
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2225.code
2226(cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2227.endd
2228.cindex "installing Exim" "install script options"
168e428f
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2229There are two other options that can be supplied to the installation script.
2230
9b371988
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2231.ilist
2232&%-no_chown%& bypasses the call to change the owner of the installed binary
168e428f 2233to root, and the call to make it a setuid binary.
9b371988
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2234.next
2235&%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
168e428f 2236installed binary.
9b371988 2237.endlist
168e428f
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2238
2239INSTALL_ARG can be used to pass these options to the script. For example:
9b371988
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2240.code
2241make INSTALL_ARG=-no_symlink install
2242.endd
168e428f
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2243The installation script can also be given arguments specifying which files are
2244to be copied. For example, to install just the Exim binary, and nothing else,
2245without creating the symbolic link, you could use:
9b371988
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2246.code
2247make INSTALL_ARG='-no_symlink exim' install
2248.endd
168e428f
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2249
2250
2251
9b371988
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2252.section "Installing info documentation" "SECTinsinfdoc"
2253.cindex "installing Exim" "&'info'& documentation"
2254Not all systems use the GNU &'info'& system for documentation, and for this
168e428f
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2255reason, the Texinfo source of Exim's documentation is not included in the main
2256distribution. Instead it is available separately from the ftp site (see section
9b371988 2257&<<SECTavail>>&).
168e428f 2258
9b371988
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2259If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2260source of the documentation is found in the source tree, running &`make
2261install`& automatically builds the info files and installs them.
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2262
2263
2264
9b371988
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2265.section "Setting up the spool directory"
2266.cindex "spool directory" "creating"
168e428f
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2267When it starts up, Exim tries to create its spool directory if it does not
2268exist. The Exim uid and gid are used for the owner and group of the spool
2269directory. Sub-directories are automatically created in the spool directory as
2270necessary.
2271
2272
2273
2274
9b371988
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2275.section "Testing"
2276.cindex "testing" "installation"
168e428f
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2277Having installed Exim, you can check that the run time configuration file is
2278syntactically valid by running the following command, which assumes that the
2279Exim binary directory is within your PATH environment variable:
9b371988
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2280.code
2281exim -bV
2282.endd
168e428f
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2283If there are any errors in the configuration file, Exim outputs error messages.
2284Otherwise it outputs the version number and build date,
2285the DBM library that is being used, and information about which drivers and
2286other optional code modules are included in the binary.
2287Some simple routing tests can be done by using the address testing option. For
2288example,
9b371988
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2289.display
2290&`exim -bt`& <&'local username'&>
2291.endd
168e428f 2292should verify that it recognizes a local mailbox, and
9b371988
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2293.display
2294&`exim -bt`& <&'remote address'&>
2295.endd
168e428f
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2296a remote one. Then try getting it to deliver mail, both locally and remotely.
2297This can be done by passing messages directly to Exim, without going through a
2298user agent. For example:
9b371988 2299.code
068aaea8
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2300exim -v postmaster@your.domain.example
2301From: user@your.domain.example
2302To: postmaster@your.domain.example
2303Subject: Testing Exim
168e428f 2304
068aaea8
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2305This is a test message.
2306^D
9b371988
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2307.endd
2308The &%-v%& option causes Exim to output some verification of what it is doing.
168e428f 2309In this case you should see copies of three log lines, one for the message's
9b371988 2310arrival, one for its delivery, and one containing &"Completed"&.
168e428f 2311
9b371988
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2312.cindex "delivery" "problems with"
2313If you encounter problems, look at Exim's log files (&'mainlog'& and
2314&'paniclog'&) to see if there is any relevant information there. Another source
168e428f 2315of information is running Exim with debugging turned on, by specifying the
9b371988 2316&%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
168e428f 2317with debugging turned on by a command of the form
9b371988
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2318.display
2319&`exim -d -M`& <&'exim-message-id'&>
2320.endd
2321You must be root or an &"admin user"& in order to do this. The &%-d%& option
168e428f 2322produces rather a lot of output, but you can cut this down to specific areas.
9b371988
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2323For example, if you use &%-d-all+route%& only the debugging information
2324relevant to routing is included. (See the &%-d%& option in chapter
2325&<<CHAPcommandline>>& for more details.)
168e428f 2326
9b371988
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2327.cindex '&"sticky"& bit'
2328.cindex "lock files"
168e428f
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2329One specific problem that has shown up on some sites is the inability to do
2330local deliveries into a shared mailbox directory, because it does not have the
9b371988 2331&"sticky bit"& set on it. By default, Exim tries to create a lock file before
168e428f 2332writing to a mailbox file, and if it cannot create the lock file, the delivery
9b371988 2333is deferred. You can get round this either by setting the &"sticky bit"& on the
168e428f
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2334directory, or by setting a specific group for local deliveries and allowing
2335that group to create files in the directory (see the comments above the
9b371988 2336&(local_delivery)& transport in the default configuration file). Another
168e428f 2337approach is to configure Exim not to use lock files, but just to rely on
9b371988
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2338&[fcntl()]& locking instead. However, you should do this only if all user
2339agents also use &[fcntl()]& locking. For further discussion of locking issues,
2340see chapter &<<CHAPappendfile>>&.
168e428f
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2341
2342One thing that cannot be tested on a system that is already running an MTA is
2343the receipt of incoming SMTP mail on the standard SMTP port. However, the
9b371988
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2344&%-oX%& option can be used to run an Exim daemon that listens on some other
2345port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2346&'exim_checkaccess'& utility can be used to check out policy controls on
168e428f
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2347incoming SMTP mail.
2348
2349Testing a new version on a system that is already running Exim can most easily
2350be done by building a binary with a different CONFIGURE_FILE setting. From
2351within the run time configuration, all other file and directory names
2352that Exim uses can be altered, in order to keep it entirely clear of the
2353production version.
2354
2355
9b371988
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2356.section "Replacing another MTA with Exim"
2357.cindex "replacing another MTA"
168e428f
PH
2358Building and installing Exim for the first time does not of itself put it in
2359general use. The name by which the system's MTA is called by mail user agents
9b371988
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2360is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2361operating system), and it is necessary to make this name point to the &'exim'&
168e428f 2362binary in order to get the user agents to pass messages to Exim. This is
9b371988
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2363normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2364or &_/usr/lib/sendmail_&
2365.cindex "symbolic link" "to &'exim'& binary"
2366a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
168e428f
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2367privilege and executable status from the old MTA. It is then necessary to stop
2368and restart the mailer daemon, if one is running.
2369
9b371988
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2370.cindex "FreeBSD" "MTA indirection"
2371.cindex "&_/etc/mail/mailer.conf_&"
168e428f
PH
2372Some operating systems have introduced alternative ways of switching MTAs. For
2373example, if you are running FreeBSD, you need to edit the file
9b371988 2374&_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
168e428f
PH
2375described. A typical example of the contents of this file for running Exim is
2376as follows:
9b371988
PH
2377.code
2378sendmail /usr/exim/bin/exim
2379send-mail /usr/exim/bin/exim
2380mailq /usr/exim/bin/exim -bp
2381newaliases /usr/bin/true
2382.endd
2383Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2384your Exim installation is &"live"&. Check it by sending a message from your
168e428f
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2385favourite user agent.
2386
2387You should consider what to tell your users about the change of MTA. Exim may
2388have different capabilities to what was previously running, and there are
2389various operational differences such as the text of messages produced by
2390command line options and in bounce messages. If you allow your users to make
2391use of Exim's filtering capabilities, you should make the document entitled
9b371988 2392&'Exim's interface to mail filtering'& available to them.
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2393
2394
2395
9b371988
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2396.section "Upgrading Exim"
2397.cindex "upgrading Exim"
168e428f
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2398If you are already running Exim on your host, building and installing a new
2399version automatically makes it available to MUAs, or any other programs that
2400call the MTA directly. However, if you are running an Exim daemon, you do need
9b371988
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2401to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2402new binary. You do not need to stop processing mail in order to install a new
068aaea8
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2403version of Exim. The install script does not modify an existing runtime
2404configuration file.
2405
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2406
2407
2408
9b371988
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2409.section "Stopping the Exim daemon on Solaris"
2410.cindex "Solaris" "stopping Exim on"
168e428f 2411The standard command for stopping the mailer daemon on Solaris is
9b371988
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2412.code
2413/etc/init.d/sendmail stop
2414.endd
2415If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2416fails to stop Exim because it uses the command &'ps -e'& and greps the output
2417for the text &"sendmail"&; this is not present because the actual program name
2418(that is, &"exim"&) is given by the &'ps'& command with these options. A
2419solution is to replace the line that finds the process id with something like
2420.code
2421pid=`cat /var/spool/exim/exim-daemon.pid`
2422.endd
168e428f
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2423to obtain the daemon's pid directly from the file that Exim saves it in.
2424
9b371988 2425Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
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2426still be received from local processes, and if automatic delivery is configured
2427(the normal case), deliveries will still occur.
2428
2429
2430
2431
9b371988
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2432. ////////////////////////////////////////////////////////////////////////////
2433. ////////////////////////////////////////////////////////////////////////////
168e428f 2434
9b371988 2435.chapter "The Exim command line" "CHAPcommandline"
4f578862
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2436.scindex IIDclo1 "command line" "options"
2437.scindex IIDclo2 "options" "command line"
168e428f
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2438Exim's command line takes the standard Unix form of a sequence of options,
2439each starting with a hyphen character, followed by a number of arguments. The
2440options are compatible with the main options of Sendmail, and there are also
2441some additional options, some of which are compatible with Smail 3. Certain
2442combinations of options do not make sense, and provoke an error if used.
2443The form of the arguments depends on which options are set.
2444
2445
9b371988
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2446.section "Setting options by program name"
2447.cindex "&'mailq'&"
2448If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
168e428f 2449were present before any other options.
9b371988 2450The &%-bp%& option requests a listing of the contents of the mail queue on the
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2451standard output.
2452This feature is for compatibility with some systems that contain a command of
2453that name in one of the standard libraries, symbolically linked to
9b371988
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2454&_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2455
2456.cindex "&'rsmtp'&"
2457If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2458were present before any other options, for compatibility with Smail. The
2459&%-bS%& option is used for reading in a number of messages in batched SMTP
2460format.
2461
2462.cindex "&'rmail'&"
2463If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2464&%-oee%& options were present before any other options, for compatibility with
2465Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2466
2467.cindex "&'runq'&"
2468.cindex "queue runner"
2469If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2470were present before any other options, for compatibility with Smail. The &%-q%&
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2471option causes a single queue runner process to be started.
2472
9b371988
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2473.cindex "&'newaliases'&"
2474.cindex "alias file" "building"
2475.cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2476If Exim is called under the name &'newaliases'& it behaves as if the option
2477&%-bi%& were present before any other options, for compatibility with Sendmail.
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2478This option is used for rebuilding Sendmail's alias file. Exim does not have
2479the concept of a single alias file, but can be configured to run a given
9b371988 2480command if called with the &%-bi%& option.
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2481
2482
9b371988
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2483.section "Trusted and admin users" "SECTtrustedadmin"
2484Some Exim options are available only to &'trusted users'& and others are
2485available only to &'admin users'&. In the description below, the phrases &"Exim
2486user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2487EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2488&%exim_group%& options. These do not necessarily have to use the name &"exim"&.
168e428f 2489
9b371988
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2490.ilist
2491.cindex "trusted user" "definition of"
2492.cindex "user" "trusted definition of"
168e428f 2493The trusted users are root, the Exim user, any user listed in the
9b371988
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2494&%trusted_users%& configuration option, and any user whose current group or any
2495supplementary group is one of those listed in the &%trusted_groups%&
168e428f 2496configuration option. Note that the Exim group is not automatically trusted.
9b371988
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2497
2498.cindex '&"From"& line'
2499.cindex "envelope sender"
2500Trusted users are always permitted to use the &%-f%& option or a leading
2501&"From&~"& line to specify the envelope sender of a message that is passed to
2502Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2503See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2504users to set envelope senders.
2505
2506.cindex "&'From:'& header line"
2507.cindex "&'Sender:'& header line"
2508For a trusted user, there is never any check on the contents of the &'From:'&
2509header line, and a &'Sender:'& line is never added. Furthermore, any existing
2510&'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2511
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2512Trusted users may also specify a host name, host address, interface address,
2513protocol name, ident value, and authentication data when submitting a message
2514locally. Thus, they are able to insert messages into Exim's queue locally that
2515have the characteristics of messages received from a remote host. Untrusted
9b371988 2516users may in some circumstances use &%-f%&, but can never set the other values
168e428f 2517that are available to trusted users.
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2518.next
2519.cindex "user" "admin definition of"
2520.cindex "admin user" "definition of"
168e428f 2521The admin users are root, the Exim user, and any user that is a member of the
9b371988 2522Exim group or of any group listed in the &%admin_groups%& configuration option.
168e428f 2523The current group does not have to be one of these groups.
9b371988 2524
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2525Admin users are permitted to list the queue, and to carry out certain
2526operations on messages, for example, to force delivery failures. It is also
2527necessary to be an admin user in order to see the full information provided by
2528the Exim monitor, and full debugging output.
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2529
2530By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2531Exim to attempt delivery of messages on its queue is restricted to admin users.
2532However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2533option false (that is, specifying &%no_prod_requires_admin%&).
2534
2535Similarly, the use of the &%-bp%& option to list all the messages in the queue
2536is restricted to admin users unless &%queue_list_requires_admin%& is set
168e428f 2537false.
9b371988 2538.endlist
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2539
2540
9b371988 2541&*Warning*&: If you configure your system so that admin users are able to
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2542edit Exim's configuration file, you are giving those users an easy way of
2543getting root. There is further discussion of this issue at the start of chapter
9b371988 2544&<<CHAPconf>>&.
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2545
2546
2547
2548
9b371988 2549.section "Command line options"
db9452a9
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2550Exim's command line options are described in alphabetical order below. If none
2551of the options that specifies a specific action (such as starting the daemon or
2552a queue runner, or testing an address, or receiving a message in a specific
2553format, or listing the queue) are present, and there is at least one argument
2554on the command line, &%-bm%& (accept a local message on the standard input,
2555with the arguments specifying the recipients) is assumed. Otherwise, Exim
2556outputs a brief message about itself and exits.
168e428f 2557
9b371988
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2558. ////////////////////////////////////////////////////////////////////////////
2559. Insert a stylized XML comment here, to identify the start of the command line
2560. options. This is for the benefit of the Perl script that automatically
2561. creates a man page for the options.
2562. ////////////////////////////////////////////////////////////////////////////
168e428f 2563
9b371988 2564.literal xml
168e428f 2565<!-- === Start of command line options === -->
9b371988 2566.literal off
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2567
2568
9b371988
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2569.vlist
2570.vitem &%--%&
2571.oindex "--"
2572.cindex "options" "command line; terminating"
168e428f
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2573This is a pseudo-option whose only purpose is to terminate the options and
2574therefore to cause subsequent command line items to be treated as arguments
2575rather than options, even if they begin with hyphens.
2576
9b371988
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2577.vitem &%--help%&
2578.oindex "&%--help%&"
168e428f
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2579This option causes Exim to output a few sentences stating what it is.
2580The same output is generated if the Exim binary is called with no options and
2581no arguments.
2582
9b371988
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2583.vitem &%-B%&<&'type'&>
2584.oindex "&%-B%&"
2585.cindex "8-bit characters"
2586.cindex "Sendmail compatibility" "8-bit characters"
168e428f
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2587This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2588clean; it ignores this option.
2589
9b371988
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2590.vitem &%-bd%&
2591.oindex "&%-bd%&"
2592.cindex "daemon"
2593.cindex "SMTP listener"
2594.cindex "queue runner"
168e428f 2595This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
9b371988
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2596the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2597that the daemon should also initiate periodic queue runs.
2598
2599The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2600(debugging) or &%-v%& (verifying) options are set, the daemon does not
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2601disconnect from the controlling terminal. When running this way, it can be
2602stopped by pressing ctrl-C.
9b371988 2603
168e428f
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2604By default, Exim listens for incoming connections to the standard SMTP port on
2605all the host's running interfaces. However, it is possible to listen on other
2606ports, on multiple ports, and only on specific interfaces. Chapter
9b371988
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2607&<<CHAPinterfaces>>& contains a description of the options that control this.
2608
168e428f 2609When a listening daemon
9b371988
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2610.cindex "daemon" "process id (pid)"
2611.cindex "pid (process id)" "of daemon"
2612is started without the use of &%-oX%& (that is, without overriding the normal
2613configuration), it writes its process id to a file called &_exim-daemon.pid_&
2614in Exim's spool directory. This location can be overridden by setting
2615PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
168e428f 2616running as root.
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2617
2618When &%-oX%& is used on the command line to start a listening daemon, the
2619process id is not written to the normal pid file path. However, &%-oP%& can be
168e428f 2620used to specify a path on the command line if a pid file is required.
9b371988 2621
168e428f 2622The SIGHUP signal
9b371988 2623.cindex "SIGHUP"
3cb1b51e
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2624.cindex "daemon" "restarting"
2625can be used to cause the daemon to re-execute itself. This should be done
2626whenever Exim's configuration file, or any file that is incorporated into it by
2627means of the &%.include%& facility, is changed, and also whenever a new version
2628of Exim is installed. It is not necessary to do this when other files that are
9b371988
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2629referenced from the configuration (for example, alias files) are changed,
2630because these are reread each time they are used.
2631
2632.vitem &%-bdf%&
2633.oindex "&%-bdf%&"
2634This option has the same effect as &%-bd%& except that it never disconnects
2635from the controlling terminal, even when no debugging is specified.
2636
2637.vitem &%-be%&
2638.oindex "&%-be%&"
2639.cindex "testing" "string expansion"
2640.cindex "expansion" "testing"
168e428f
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2641Run Exim in expansion testing mode. Exim discards its root privilege, to
2642prevent ordinary users from using this mode to read otherwise inaccessible
2643files. If no arguments are given, Exim runs interactively, prompting for lines
4f578862 2644of data. Otherwise, it processes each argument in turn.
9b371988
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2645
2646If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2647to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2648used without command line arguments. If successful, it uses the &[readline()]&
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2649function, which provides extensive line-editing facilities, for reading the
2650test data. A line history is supported.
9b371988 2651
168e428f 2652Long expansion expressions can be split over several lines by using backslash
068aaea8 2653continuations. As in Exim's run time configuration, white space at the start of
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2654continuation lines is ignored. Each argument or data line is passed through the
2655string expansion mechanism, and the result is output. Variable values from the
9b371988 2656configuration file (for example, &$qualify_domain$&) are available, but no
3cb1b51e
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2657message-specific values (such as &$sender_domain$&) are set, because no message
2658is being processed &new("(but see &%-bem%& and &%-Mset%&)").
168e428f 2659
9b371988
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2660&*Note*&: If you use this mechanism to test lookups, and you change the data
2661files or databases you are using, you must exit and restart Exim before trying
2662the same lookup again. Otherwise, because each Exim process caches the results
2663of lookups, you will just get the same result as before.
9b371988 2664
3cb1b51e
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2665.new
2666.vitem &%-bem%&&~<&'filename'&>
2667.oindex "&%-bem%&"
2668.cindex "testing" "string expansion"
2669.cindex "expansion" "testing"
2670This option operates like &%-be%& except that it must be followed by the name
2671of a file. For example:
2672.code
2673exim -bem /tmp/testmessage
2674.endd
2675The file is read as a message (as if receiving a locally-submitted non-SMTP
2676message) before any of the test expansions are done. Thus, message-specific
2677variables such as &$message_size$& and &$header_from:$& are available. However,
2678no &'Received:'& header is added to the message. If the &%-t%& option is set,
2679recipients are read from the headers in the normal way, and are shown in the
2680&$recipients$& variable. Note that recipients cannot be given on the command
2681line, because further arguments are taken as strings to expand (just like
2682&%-be%&).
2683.wen
2684
9b371988
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2685.vitem &%-bF%&&~<&'filename'&>
2686.oindex "&%-bF%&"
2687.cindex "system filter" "testing"
2688.cindex "testing" "system filter"
2689This option is the same as &%-bf%& except that it assumes that the filter being
168e428f
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2690tested is a system filter. The additional commands that are available only in
2691system filters are recognized.
2692
9b371988
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2693.vitem &%-bf%&&~<&'filename'&>
2694.oindex "&%-bf%&"
2695.cindex "filter" "testing"
2696.cindex "testing" "filter file"
2697.cindex "forward file" "testing"
2698.cindex "testing" "forward file"
2699.cindex "Sieve filter" "testing"
168e428f
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2700This option runs Exim in user filter testing mode; the file is the filter file
2701to be tested, and a test message must be supplied on the standard input. If
2702there are no message-dependent tests in the filter, an empty file can be
2703supplied.
168e428f 2704
9b371988
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2705If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2706can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2707filter and a user filter in the same run. For example:
2708.code
2709exim -bF /system/filter -bf /user/filter </test/message
2710.endd
168e428f
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2711This is helpful when the system filter adds header lines or sets filter
2712variables that are used by the user filter.
168e428f 2713
9b371988
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2714If the test filter file does not begin with one of the special lines
2715.code
2716# Exim filter
2717# Sieve filter
2718.endd
2719it is taken to be a normal &_.forward_& file, and is tested for validity under
2720that interpretation. See sections &<<SECTitenonfilred>>& to
2721&<<SECTspecitredli>>& for a description of the possible contents of non-filter
2722redirection lists.
2723
2724The result of an Exim command that uses &%-bf%&, provided no errors are
168e428f
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2725detected, is a list of the actions that Exim would try to take if presented
2726with the message for real. More details of filter testing are given in the
9b371988
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2727separate document entitled &'Exim's interfaces to mail filtering'&.
2728
168e428f 2729When testing a filter file,
9b371988
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2730.cindex "&""From""& line"
2731.cindex "envelope sender"
2732.cindex "&%-f%& option" "for filter testing"
2733the envelope sender can be set by the &%-f%& option,
2734or by a &"From&~"& line at the start of the test message. Various parameters
2735that would normally be taken from the envelope recipient address of the message
2736can be set by means of additional command line options (see the next four
2737options).
2738
2739.vitem &%-bfd%&&~<&'domain'&>
2740.oindex "&%-bfd%&"
2741.cindex "&$qualify_domain$&"
168e428f 2742This sets the domain of the recipient address when a filter file is being
9b371988
PH
2743tested by means of the &%-bf%& option. The default is the value of
2744&$qualify_domain$&.
168e428f 2745
9b371988
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2746.vitem &%-bfl%&&~<&'local&~part'&>
2747.oindex "&%-bfl%&"
168e428f 2748This sets the local part of the recipient address when a filter file is being
9b371988 2749tested by means of the &%-bf%& option. The default is the username of the
168e428f
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2750process that calls Exim. A local part should be specified with any prefix or
2751suffix stripped, because that is how it appears to the filter when a message is
2752actually being delivered.
2753
9b371988
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2754.vitem &%-bfp%&&~<&'prefix'&>
2755.oindex "&%-bfp%&"
168e428f 2756This sets the prefix of the local part of the recipient address when a filter
9b371988 2757file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
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2758prefix.
2759
9b371988
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2760.vitem &%-bfs%&&~<&'suffix'&>
2761.oindex "&%-bfs%&"
168e428f 2762This sets the suffix of the local part of the recipient address when a filter
9b371988 2763file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
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2764suffix.
2765
9b371988
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2766.vitem &%-bh%&&~<&'IP&~address'&>
2767.oindex "&%-bh%&"
2768.cindex "testing" "incoming SMTP"
2769.cindex "SMTP" "testing incoming"
2770.cindex "testing" "relay control"
2771.cindex "relaying" "testing configuration"
2772.cindex "policy control" "testing"
2773.cindex "debugging" "&%-bh%& option"
168e428f
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2774This option runs a fake SMTP session as if from the given IP address, using the
2775standard input and output. The IP address may include a port number at the end,
2776after a full stop. For example:
9b371988
PH
2777.code
2778exim -bh 10.9.8.7.1234
2779exim -bh fe80::a00:20ff:fe86:a061.5678
2780.endd
168e428f 2781When an IPv6 address is given, it is converted into canonical form. In the case
9b371988
PH
2782of the second example above, the value of &$sender_host_address$& after
2783conversion to the canonical form is
2784&`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2785
168e428f 2786Comments as to what is going on are written to the standard error file. These
9b371988 2787include lines beginning with &"LOG"& for anything that would have been logged.
168e428f
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2788This facility is provided for testing configuration options for incoming
2789messages, to make sure they implement the required policy. For example, you can
9b371988
PH
2790test your relay controls using &%-bh%&.
2791
2792&*Warning 1*&:
2793.cindex "RFC 1413"
db9452a9
PH
2794You can test features of the configuration that rely on ident (RFC 1413)
2795information by using the &%-oMt%& option. However, Exim cannot actually perform
2796an ident callout when testing using &%-bh%& because there is no incoming SMTP
2797connection.
9b371988
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2798
2799&*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2800are also skipped when testing using &%-bh%&. If you want these callouts to
2801occur, use &%-bhc%& instead.
2802
168e428f
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2803Messages supplied during the testing session are discarded, and nothing is
2804written to any of the real log files. There may be pauses when DNS (and other)
9b371988 2805lookups are taking place, and of course these may time out. The &%-oMi%& option
db9452a9
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2806can be used to specify a specific IP interface and port if this is important,
2807and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2808session were authenticated.
9b371988
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2809
2810The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
168e428f 2811output just states whether a given recipient address from a given host is
9b371988 2812acceptable or not. See section &<<SECTcheckaccess>>&.
168e428f 2813
3cb1b51e
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2814.new
2815Features such as authentication and encryption, where the client input is not
2816plain text, are most easily tested using specialized SMTP test programs such as
2817&url(http://jetmore.org/john/code/#swaks,swaks).
2818.wen
2819
9b371988
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2820.vitem &%-bhc%&&~<&'IP&~address'&>
2821.oindex "&%-bhc%&"
2822This option operates in the same way as &%-bh%&, except that address
168e428f
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2823verification callouts are performed if required. This includes consulting and
2824updating the callout cache database.
2825
9b371988
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2826.vitem &%-bi%&
2827.oindex "&%-bi%&"
2828.cindex "alias file" "building"
2829.cindex "building alias file"
2830.cindex "Sendmail compatibility" "&%-bi%& option"
2831Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
168e428f 2832Exim does not have the concept of a single alias file, and so it cannot mimic
9b371988 2833this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
168e428f
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2834tend to appear in various scripts such as NIS make files, so the option must be
2835recognized.
9b371988
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2836
2837If &%-bi%& is encountered, the command specified by the &%bi_command%&
168e428f 2838configuration option is run, under the uid and gid of the caller of Exim. If
9b371988
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2839the &%-oA%& option is used, its value is passed to the command as an argument.
2840The command set by &%bi_command%& may not contain arguments. The command can
2841use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2842if this is required. If the &%bi_command%& option is not set, calling Exim with
2843&%-bi%& is a no-op.
2844
2845.vitem &%-bm%&
2846.oindex "&%-bm%&"
2847.cindex "local message reception"
168e428f
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2848This option runs an Exim receiving process that accepts an incoming,
2849locally-generated message on the current input. The recipients are given as the
9b371988 2850command arguments (except when &%-t%& is also present &-- see below). Each
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2851argument can be a comma-separated list of RFC 2822 addresses. This is the
2852default option for selecting the overall action of an Exim call; it is assumed
2853if no other conflicting option is present.
9b371988 2854
168e428f 2855If any addresses in the message are unqualified (have no domain), they are
9b371988
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2856qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
2857options, as appropriate. The &%-bnq%& option (see below) provides a way of
168e428f 2858suppressing this for special cases.
9b371988 2859
168e428f 2860Policy checks on the contents of local messages can be enforced by means of
9b371988
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2861the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
2862
2863.cindex "return code" "for &%-bm%&"
2864The return code is zero if the message is successfully accepted. Otherwise, the
2865action is controlled by the &%-oe%&&'x'& option setting &-- see below.
2866
168e428f 2867The format
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2868.cindex "message" "format"
2869.cindex "format" "message"
2870.cindex "&""From""& line"
2871.cindex "UUCP" "&""From""& line"
2872.cindex "Sendmail compatibility" "&""From""& line"
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2873of the message must be as defined in RFC 2822, except that, for
2874compatibility with Sendmail and Smail, a line in one of the forms
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2875.code
2876From sender Fri Jan 5 12:55 GMT 1997
2877From sender Fri, 5 Jan 97 12:55:01
2878.endd
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2879(with the weekday optional, and possibly with additional text after the date)
2880is permitted to appear at the start of the message. There appears to be no
2881authoritative specification of the format of this line. Exim recognizes it by
9b371988 2882matching against the regular expression defined by the &%uucp_from_pattern%&
168e428f 2883option, which can be changed if necessary.
9b371988 2884
168e428f 2885The
9b371988 2886.cindex "&%-f%& option" "overriding &""From""& line"
168e428f 2887specified sender is treated as if it were given as the argument to the
9b371988 2888&%-f%& option, but if a &%-f%& option is also present, its argument is used in
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2889preference to the address taken from the message. The caller of Exim must be a
2890trusted user for the sender of a message to be set in this way.
2891
9b371988
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2892.vitem &%-bnq%&
2893.oindex "&%-bnq%&"
2894.cindex "address qualification" "suppressing"
168e428f
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2895By default, Exim automatically qualifies unqualified addresses (those
2896without domains) that appear in messages that are submitted locally (that
2897is, not over TCP/IP). This qualification applies both to addresses in
2898envelopes, and addresses in header lines. Sender addresses are qualified using
9b371988
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2899&%qualify_domain%&, and recipient addresses using &%qualify_recipient%& (which
2900defaults to the value of &%qualify_domain%&).
2901
2902Sometimes, qualification is not wanted. For example, if &%-bS%& (batch SMTP) is
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2903being used to re-submit messages that originally came from remote hosts after
2904content scanning, you probably do not want to qualify unqualified addresses in
2905header lines. (Such lines will be present only if you have not enabled a header
2906syntax check in the appropriate ACL.)
9b371988
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2907
2908The &%-bnq%& option suppresses all qualification of unqualified addresses in
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2909messages that originate on the local host. When this is used, unqualified
2910addresses in the envelope provoke errors (causing message rejection) and
2911unqualified addresses in header lines are left alone.
2912
2913
9b371988
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2914.vitem &%-bP%&
2915.oindex "&%-bP%&"
2916.cindex "configuration options" "extracting"
2917.cindex "options" "configuration &-- extracting"
168e428f
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2918If this option is given with no arguments, it causes the values of all Exim's
2919main configuration options to be written to the standard output. The values
2920of one or more specific options can be requested by giving their names as
2921arguments, for example:
9b371988
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2922.code
2923exim -bP qualify_domain hold_domains
2924.endd
2925However, any option setting that is preceded by the word &"hide"& in the
168e428f
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2926configuration file is not shown in full, except to an admin user. For other
2927users, the output is as in this example:
9b371988
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2928.code
2929mysql_servers = <value not displayable>
2930.endd
2931If &%configure_file%& is given as an argument, the name of the run time
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2932configuration file is output.
2933If a list of configuration files was supplied, the value that is output here
2934is the name of the file that was actually used.
168e428f 2935
9b371988
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2936.cindex "daemon" "process id (pid)"
2937.cindex "pid (process id)" "of daemon"
2938If &%log_file_path%& or &%pid_file_path%& are given, the names of the
2939directories where log files and daemon pid files are written are output,
2940respectively. If these values are unset, log files are written in a
2941sub-directory of the spool directory called &%log%&, and the pid file is
2942written directly into the spool directory.
2943
2944If &%-bP%& is followed by a name preceded by &`+`&, for example,
2945.code
2946exim -bP +local_domains
2947.endd
168e428f
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2948it searches for a matching named list of any type (domain, host, address, or
2949local part) and outputs what it finds.
9b371988
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2950
2951.cindex "options" "router &-- extracting"
2952.cindex "options" "transport &-- extracting"
2953If one of the words &%router%&, &%transport%&, or &%authenticator%& is given,
168e428f
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2954followed by the name of an appropriate driver instance, the option settings for
2955that driver are output. For example:
9b371988
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2956.code
2957exim -bP transport local_delivery
2958.endd
168e428f
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2959The generic driver options are output first, followed by the driver's private
2960options. A list of the names of drivers of a particular type can be obtained by
9b371988
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2961using one of the words &%router_list%&, &%transport_list%&, or
2962&%authenticator_list%&, and a complete list of all drivers with their option
2963settings can be obtained by using &%routers%&, &%transports%&, or
2964&%authenticators%&.
168e428f
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2965
2966
9b371988
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2967.vitem &%-bp%&
2968.oindex "&%-bp%&"
2969.cindex "queue" "listing messages on"
2970.cindex "listing" "messages on the queue"
168e428f 2971This option requests a listing of the contents of the mail queue on the
9b371988 2972standard output. If the &%-bp%& option is followed by a list of message ids,
168e428f 2973just those messages are listed. By default, this option can be used only by an
9b371988 2974admin user. However, the &%queue_list_requires_admin%& option can be set false
168e428f 2975to allow any user to see the queue.
168e428f 2976
9b371988
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2977Each message on the queue is displayed as in the following example:
2978.code
297925m 2.9K 0t5C6f-0000c8-00 <alice@wonderland.fict.example>
2980 red.king@looking-glass.fict.example
2981 <other addresses>
2982.endd
2983.cindex "message" "size in queue listing"
2984.cindex "size" "of message"
2985The first line contains the length of time the message has been on the queue
168e428f
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2986(in this case 25 minutes), the size of the message (2.9K), the unique local
2987identifier for the message, and the message sender, as contained in the
2988envelope. For bounce messages, the sender address is empty, and appears as
9b371988 2989&"<>"&. If the message was submitted locally by an untrusted user who overrode
168e428f
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2990the default sender address, the user's login name is shown in parentheses
2991before the sender address.
9b371988
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2992
2993.cindex "frozen messages" "in queue listing"
2994If the message is frozen (attempts to deliver it are suspended) then the text
2995&"*** frozen ***"& is displayed at the end of this line.
2996
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2997The recipients of the message (taken from the envelope, not the headers) are
2998displayed on subsequent lines. Those addresses to which the message has already
2999been delivered are marked with the letter D. If an original address gets
3000expanded into several addresses via an alias or forward file, the original is
3001displayed with a D only when deliveries for all of its child addresses are
3002complete.
3003
3004
9b371988
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3005.vitem &%-bpa%&
3006.oindex "&%-bpa%&"
3007This option operates like &%-bp%&, but in addition it shows delivered addresses
168e428f 3008that were generated from the original top level address(es) in each message by
9b371988
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3009alias or forwarding operations. These addresses are flagged with &"+D"& instead
3010of just &"D"&.
168e428f
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3011
3012
9b371988
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3013.vitem &%-bpc%&
3014.oindex "&%-bpc%&"
3015.cindex "queue" "count of messages on"
168e428f
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3016This option counts the number of messages on the queue, and writes the total
3017to the standard output. It is restricted to admin users, unless
9b371988 3018&%queue_list_requires_admin%& is set false.
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3019
3020
9b371988
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3021.vitem &%-bpr%&
3022.oindex "&%-bpr%&"
3023This option operates like &%-bp%&, but the output is not sorted into
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3024chronological order of message arrival. This can speed it up when there are
3025lots of messages on the queue, and is particularly useful if the output is
3026going to be post-processed in a way that doesn't need the sorting.
3027
9b371988
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3028.vitem &%-bpra%&
3029.oindex "&%-bpra%&"
3030This option is a combination of &%-bpr%& and &%-bpa%&.
168e428f 3031
9b371988
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3032.vitem &%-bpru%&
3033.oindex "&%-bpru%&"
3034This option is a combination of &%-bpr%& and &%-bpu%&.
168e428f
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3035
3036
9b371988
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3037.vitem &%-bpu%&
3038.oindex "&%-bpu%&"
3039This option operates like &%-bp%& but shows only undelivered top-level
3040addresses for each message displayed. Addresses generated by aliasing or
3041forwarding are not shown, unless the message was deferred after processing by a
3042router with the &%one_time%& option set.
168e428f
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3043
3044
9b371988
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3045.vitem &%-brt%&
3046.oindex "&%-brt%&"
3047.cindex "testing" "retry configuration"
3048.cindex "retry" "configuration testing"
168e428f
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3049This option is for testing retry rules, and it must be followed by up to three
3050arguments. It causes Exim to look for a retry rule that matches the values
3051and to write it to the standard output. For example:
9b371988
PH
3052.code
3053exim -brt bach.comp.mus.example
3054Retry rule: *.comp.mus.example F,2h,15m; F,4d,30m;
3055.endd
3056See chapter &<<CHAPretry>>& for a description of Exim's retry rules. The first
168e428f 3057argument, which is required, can be a complete address in the form
4f578862
PH
3058&'local_part@domain'&, or it can be just a domain name. If the second argument
3059contains a dot, it is interpreted as an optional second domain name; if no
3060retry rule is found for the first argument, the second is tried. This ties in
3061with Exim's behaviour when looking for retry rules for remote hosts &-- if no
3062rule is found that matches the host, one that matches the mail domain is
3063sought. Finally, an argument that is the name of a specific delivery error, as
3064used in setting up retry rules, can be given. For example:
3065.code
3066exim -brt haydn.comp.mus.example quota_3d
3067Retry rule: *@haydn.comp.mus.example quota_3d F,1h,15m
3068.endd
168e428f 3069
9b371988
PH
3070.vitem &%-brw%&
3071.oindex "&%-brw%&"
3072.cindex "testing" "rewriting"
3073.cindex "rewriting" "testing"
168e428f
PH
3074This option is for testing address rewriting rules, and it must be followed by
3075a single argument, consisting of either a local part without a domain, or a
3076complete address with a fully qualified domain. Exim outputs how this address
3077would be rewritten for each possible place it might appear. See chapter
9b371988 3078&<<CHAPrewrite>>& for further details.
168e428f 3079
9b371988
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3080.vitem &%-bS%&
3081.oindex "&%-bS%&"
3082.cindex "SMTP" "batched incoming"
3083.cindex "batched SMTP input"
168e428f
PH
3084This option is used for batched SMTP input, which is an alternative interface
3085for non-interactive local message submission. A number of messages can be
3086submitted in a single run. However, despite its name, this is not really SMTP
3087input. Exim reads each message's envelope from SMTP commands on the standard
3088input, but generates no responses. If the caller is trusted, or
9b371988 3089&%untrusted_set_sender%& is set, the senders in the SMTP MAIL commands are
168e428f 3090believed; otherwise the sender is always the caller of Exim.
9b371988 3091
168e428f
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3092The message itself is read from the standard input, in SMTP format (leading
3093dots doubled), terminated by a line containing just a single dot. An error is
3094provoked if the terminating dot is missing. A further message may then follow.
9b371988 3095
168e428f 3096As for other local message submissions, the contents of incoming batch SMTP
9b371988
PH
3097messages can be checked using the non-SMTP ACL (see chapter &<<CHAPACL>>&).
3098Unqualified addresses are automatically qualified using &%qualify_domain%& and
3099&%qualify_recipient%&, as appropriate, unless the &%-bnq%& option is used.
3100
168e428f
PH
3101Some other SMTP commands are recognized in the input. HELO and EHLO act
3102as RSET; VRFY, EXPN, ETRN, and HELP act as NOOP;
3103QUIT quits, ignoring the rest of the standard input.
9b371988
PH
3104
3105.cindex "return code" "for &%-bS%&"
168e428f
PH
3106If any error is encountered, reports are written to the standard output and
3107error streams, and Exim gives up immediately. The return code is 0 if no error
3108was detected; it is 1 if one or more messages were accepted before the error
3109was detected; otherwise it is 2.
9b371988 3110
168e428f 3111More details of input using batched SMTP are given in section
9b371988 3112&<<SECTincomingbatchedSMTP>>&.
168e428f 3113
9b371988
PH
3114.vitem &%-bs%&
3115.oindex "&%-bs%&"
3116.cindex "SMTP" "local input"
3117.cindex "local SMTP input"
168e428f
PH
3118This option causes Exim to accept one or more messages by reading SMTP commands
3119on the standard input, and producing SMTP replies on the standard output. SMTP
9b371988 3120policy controls, as defined in ACLs (see chapter &<<CHAPACL>>&) are applied.
168e428f
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3121Some user agents use this interface as a way of passing locally-g