Doc fix: log field M8S=, in details section
[exim.git] / doc / doc-docbook / spec.xfpt
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1. /////////////////////////////////////////////////////////////////////////////
2. This is the primary source of the Exim Manual. It is an xfpt document that is
3. converted into DocBook XML for subsequent conversion into printing and online
4. formats. The markup used herein is "standard" xfpt markup, with some extras.
5. The markup is summarized in a file called Markup.txt.
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6.
7. WARNING: When you use the .new macro, make sure it appears *before* any
8. adjacent index items; otherwise you get an empty "paragraph" which causes
9. unwanted vertical space.
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10. /////////////////////////////////////////////////////////////////////////////
11
12.include stdflags
13.include stdmacs
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14
15. /////////////////////////////////////////////////////////////////////////////
33393583 16. This outputs the standard DocBook boilerplate.
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17. /////////////////////////////////////////////////////////////////////////////
18
33393583 19.docbook
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20
21. /////////////////////////////////////////////////////////////////////////////
22. These lines are processing instructions for the Simple DocBook Processor that
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23. Philip Hazel has developed as a less cumbersome way of making PostScript and
24. PDFs than using xmlto and fop. They will be ignored by all other XML
25. processors.
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26. /////////////////////////////////////////////////////////////////////////////
27
28.literal xml
29<?sdop
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30 foot_right_recto="&chaptertitle; (&chapternumber;)"
31 foot_right_verso="&chaptertitle; (&chapternumber;)"
3cb1b51e 32 toc_chapter_blanks="yes,yes"
595028e4 33 table_warn_overflow="overprint"
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34?>
35.literal off
9b371988 36
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37. /////////////////////////////////////////////////////////////////////////////
38. This generate the outermost <book> element that wraps then entire document.
39. /////////////////////////////////////////////////////////////////////////////
40
41.book
42
43. /////////////////////////////////////////////////////////////////////////////
44. These definitions set some parameters and save some typing. Remember that
45. the <bookinfo> element must also be updated for each new edition.
46. /////////////////////////////////////////////////////////////////////////////
47
2341d632 48.set previousversion "4.80"
c4ceed07 49.set version "4.80"
f89d2485 50
33393583 51.set ACL "access control lists (ACLs)"
f89d2485 52.set I "&nbsp;&nbsp;&nbsp;&nbsp;"
33393583 53
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54
55. /////////////////////////////////////////////////////////////////////////////
56. Additional xfpt markup used by this document, over and above the default
57. provided in the xfpt library.
58. /////////////////////////////////////////////////////////////////////////////
59
60. --- Override the &$ flag to automatically insert a $ with the variable name
61
62.flag &$ $& "<varname>$" "</varname>"
63
64. --- Short flags for daggers in option headings. They will always be inside
65. --- an italic string, but we want the daggers to be roman.
66
67.flag &!! "</emphasis>&dagger;<emphasis>"
68.flag &!? "</emphasis>&Dagger;<emphasis>"
69
70. --- A macro for an Exim option definition heading, generating a one-line
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71. --- table with four columns. For cases when the option name is given with
72. --- a space, so that it can be split, a fifth argument is used for the
73. --- index entry.
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74
75.macro option
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76.arg 5
77.oindex "&%$5%&"
78.endarg
79.arg -5
3cb1b51e 80.oindex "&%$1%&"
0a4e3112 81.endarg
f89d2485 82.itable all 0 0 4 8* left 6* center 6* center 6* right
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83.row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&"
84.endtable
85.endmacro
86
87. --- A macro for the common 2-column tables. The width of the first column
88. --- is suitable for the many tables at the start of the main options chapter;
89. --- the small number of other 2-column tables override it.
90
db9452a9 91.macro table2 196pt 254pt
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92.itable none 0 0 2 $1 left $2 left
93.endmacro
94
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95. --- A macro that generates .row, but puts &I; at the start of the first
96. --- argument, thus indenting it. Assume a minimum of two arguments, and
97. --- allow up to four arguments, which is as many as we'll ever need.
98
99.macro irow
100.arg 4
101.row "&I;$1" "$2" "$3" "$4"
102.endarg
103.arg -4
104.arg 3
105.row "&I;$1" "$2" "$3"
106.endarg
107.arg -3
108.row "&I;$1" "$2"
109.endarg
110.endarg
111.endmacro
112
113. --- Macros for option, variable, and concept index entries. For a "range"
114. --- style of entry, use .scindex for the start and .ecindex for the end. The
115. --- first argument of .scindex and the only argument of .ecindex must be the
116. --- ID that ties them together.
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117
118.macro cindex
119&<indexterm role="concept">&
120&<primary>&$1&</primary>&
121.arg 2
122&<secondary>&$2&</secondary>&
123.endarg
124&</indexterm>&
125.endmacro
126
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127.macro scindex
128&<indexterm role="concept" id="$1" class="startofrange">&
129&<primary>&$2&</primary>&
130.arg 3
131&<secondary>&$3&</secondary>&
132.endarg
133&</indexterm>&
134.endmacro
135
136.macro ecindex
137&<indexterm role="concept" startref="$1" class="endofrange"/>&
138.endmacro
139
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140.macro oindex
141&<indexterm role="option">&
142&<primary>&$1&</primary>&
143.arg 2
144&<secondary>&$2&</secondary>&
145.endarg
146&</indexterm>&
147.endmacro
148
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149.macro vindex
150&<indexterm role="variable">&
151&<primary>&$1&</primary>&
152.arg 2
153&<secondary>&$2&</secondary>&
154.endarg
155&</indexterm>&
156.endmacro
157
9b371988 158.macro index
f89d2485 159.echo "** Don't use .index; use .cindex or .oindex or .vindex"
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160.endmacro
161. ////////////////////////////////////////////////////////////////////////////
162
163
164. ////////////////////////////////////////////////////////////////////////////
165. The <bookinfo> element is removed from the XML before processing for Ascii
166. output formats.
167. ////////////////////////////////////////////////////////////////////////////
168
169.literal xml
170<bookinfo>
171<title>Specification of the Exim Mail Transfer Agent</title>
172<titleabbrev>The Exim MTA</titleabbrev>
c4ceed07 173<date>17 May 2012</date>
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174<author><firstname>Exim</firstname><surname>Maintainers</surname></author>
175<authorinitials>EM</authorinitials>
9b371988 176<revhistory><revision>
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177 <revnumber>4.80</revnumber>
178 <date>17 May 2012</date>
7b4c60eb 179 <authorinitials>EM</authorinitials>
9b371988 180</revision></revhistory>
c4ceed07 181<copyright><year>2012</year><holder>University of Cambridge</holder></copyright>
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182</bookinfo>
183.literal off
184
185
186. /////////////////////////////////////////////////////////////////////////////
187. This chunk of literal XML implements index entries of the form "x, see y" and
188. "x, see also y". However, the DocBook DTD doesn't allow <indexterm> entries
189. at the top level, so we have to put the .chapter directive first.
190. /////////////////////////////////////////////////////////////////////////////
191
f89d2485 192.chapter "Introduction" "CHID1"
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193.literal xml
194
f89d2485 195<indexterm role="variable">
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196 <primary>$1, $2, etc.</primary>
197 <see><emphasis>numerical variables</emphasis></see>
198</indexterm>
199<indexterm role="concept">
200 <primary>address</primary>
201 <secondary>rewriting</secondary>
202 <see><emphasis>rewriting</emphasis></see>
203</indexterm>
204<indexterm role="concept">
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205 <primary>Bounce Address Tag Validation</primary>
206 <see><emphasis>BATV</emphasis></see>
207</indexterm>
208<indexterm role="concept">
209 <primary>Client SMTP Authorization</primary>
210 <see><emphasis>CSA</emphasis></see>
211</indexterm>
212<indexterm role="concept">
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213 <primary>CR character</primary>
214 <see><emphasis>carriage return</emphasis></see>
215</indexterm>
216<indexterm role="concept">
217 <primary>CRL</primary>
218 <see><emphasis>certificate revocation list</emphasis></see>
219</indexterm>
220<indexterm role="concept">
221 <primary>delivery</primary>
222 <secondary>failure report</secondary>
223 <see><emphasis>bounce message</emphasis></see>
224</indexterm>
225<indexterm role="concept">
226 <primary>dialup</primary>
227 <see><emphasis>intermittently connected hosts</emphasis></see>
228</indexterm>
229<indexterm role="concept">
230 <primary>exiscan</primary>
231 <see><emphasis>content scanning</emphasis></see>
232</indexterm>
233<indexterm role="concept">
234 <primary>failover</primary>
235 <see><emphasis>fallback</emphasis></see>
236</indexterm>
237<indexterm role="concept">
238 <primary>fallover</primary>
239 <see><emphasis>fallback</emphasis></see>
240</indexterm>
241<indexterm role="concept">
242 <primary>filter</primary>
243 <secondary>Sieve</secondary>
244 <see><emphasis>Sieve filter</emphasis></see>
245</indexterm>
246<indexterm role="concept">
247 <primary>ident</primary>
248 <see><emphasis>RFC 1413</emphasis></see>
249</indexterm>
250<indexterm role="concept">
251 <primary>LF character</primary>
252 <see><emphasis>linefeed</emphasis></see>
253</indexterm>
254<indexterm role="concept">
255 <primary>maximum</primary>
595028e4 256 <seealso><emphasis>limit</emphasis></seealso>
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257</indexterm>
258<indexterm role="concept">
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259 <primary>monitor</primary>
260 <see><emphasis>Exim monitor</emphasis></see>
261</indexterm>
262<indexterm role="concept">
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263 <primary>no_<emphasis>xxx</emphasis></primary>
264 <see>entry for xxx</see>
265</indexterm>
266<indexterm role="concept">
267 <primary>NUL</primary>
268 <see><emphasis>binary zero</emphasis></see>
269</indexterm>
270<indexterm role="concept">
271 <primary>passwd file</primary>
272 <see><emphasis>/etc/passwd</emphasis></see>
273</indexterm>
274<indexterm role="concept">
275 <primary>process id</primary>
276 <see><emphasis>pid</emphasis></see>
277</indexterm>
278<indexterm role="concept">
279 <primary>RBL</primary>
280 <see><emphasis>DNS list</emphasis></see>
281</indexterm>
282<indexterm role="concept">
283 <primary>redirection</primary>
284 <see><emphasis>address redirection</emphasis></see>
285</indexterm>
286<indexterm role="concept">
287 <primary>return path</primary>
288 <seealso><emphasis>envelope sender</emphasis></seealso>
289</indexterm>
290<indexterm role="concept">
291 <primary>scanning</primary>
292 <see><emphasis>content scanning</emphasis></see>
293</indexterm>
294<indexterm role="concept">
295 <primary>SSL</primary>
296 <see><emphasis>TLS</emphasis></see>
297</indexterm>
298<indexterm role="concept">
299 <primary>string</primary>
300 <secondary>expansion</secondary>
301 <see><emphasis>expansion</emphasis></see>
302</indexterm>
303<indexterm role="concept">
304 <primary>top bit</primary>
305 <see><emphasis>8-bit characters</emphasis></see>
306</indexterm>
307<indexterm role="concept">
308 <primary>variables</primary>
309 <see><emphasis>expansion, variables</emphasis></see>
310</indexterm>
311<indexterm role="concept">
312 <primary>zero, binary</primary>
313 <see><emphasis>binary zero</emphasis></see>
314</indexterm>
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315
316.literal off
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317
318
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319. /////////////////////////////////////////////////////////////////////////////
320. This is the real start of the first chapter. See the comment above as to why
321. we can't have the .chapter line here.
322. chapter "Introduction"
323. /////////////////////////////////////////////////////////////////////////////
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324
325Exim is a mail transfer agent (MTA) for hosts that are running Unix or
326Unix-like operating systems. It was designed on the assumption that it would be
327run on hosts that are permanently connected to the Internet. However, it can be
328used on intermittently connected hosts with suitable configuration adjustments.
329
330Configuration files currently exist for the following operating systems: AIX,
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331BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, Dragonfly, FreeBSD, GNU/Hurd,
332GNU/Linux, HI-OSF (Hitachi), HI-UX, HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD,
333OpenUNIX, QNX, SCO, SCO SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4,
334Tru64-Unix (formerly Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware.
335Some of these operating systems are no longer current and cannot easily be
336tested, so the configuration files may no longer work in practice.
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337
338There are also configuration files for compiling Exim in the Cygwin environment
339that can be installed on systems running Windows. However, this document does
340not contain any information about running Exim in the Cygwin environment.
341
342The terms and conditions for the use and distribution of Exim are contained in
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343the file &_NOTICE_&. Exim is distributed under the terms of the GNU General
344Public Licence, a copy of which may be found in the file &_LICENCE_&.
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345
346The use, supply or promotion of Exim for the purpose of sending bulk,
347unsolicited electronic mail is incompatible with the basic aims of the program,
348which revolve around the free provision of a service that enhances the quality
349of personal communications. The author of Exim regards indiscriminate
350mass-mailing as an antisocial, irresponsible abuse of the Internet.
351
352Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
353experience of running and working on the Smail 3 code, I could never have
354contemplated starting to write a new MTA. Many of the ideas and user interfaces
355were originally taken from Smail 3, though the actual code of Exim is entirely
356new, and has developed far beyond the initial concept.
357
358Many people, both in Cambridge and around the world, have contributed to the
359development and the testing of Exim, and to porting it to various operating
360systems. I am grateful to them all. The distribution now contains a file called
9b371988 361&_ACKNOWLEDGMENTS_&, in which I have started recording the names of
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362contributors.
363
364
f89d2485 365.section "Exim documentation" "SECID1"
800d5176 366. Keep this example change bar when updating the documentation!
b52ed2b3 367
800d5176 368.new
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369.cindex "documentation"
370This edition of the Exim specification applies to version &version; of Exim.
371Substantive changes from the &previousversion; edition are marked in some
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372renditions of the document; this paragraph is so marked if the rendition is
373capable of showing a change indicator.
800d5176 374.wen
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375
376This document is very much a reference manual; it is not a tutorial. The reader
377is expected to have some familiarity with the SMTP mail transfer protocol and
378with general Unix system administration. Although there are some discussions
379and examples in places, the information is mostly organized in a way that makes
380it easy to look up, rather than in a natural order for sequential reading.
381Furthermore, the manual aims to cover every aspect of Exim in detail, including
382a number of rarely-used, special-purpose features that are unlikely to be of
383very wide interest.
384
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385.cindex "books about Exim"
386An &"easier"& discussion of Exim which provides more in-depth explanatory,
387introductory, and tutorial material can be found in a book entitled &'The Exim
595028e4 388SMTP Mail Server'& (second edition, 2007), published by UIT Cambridge
9b371988 389(&url(http://www.uit.co.uk/exim-book/)).
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390
391This book also contains a chapter that gives a general introduction to SMTP and
392Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
393with the latest release of Exim. (Note that the earlier book about Exim,
394published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
395
9b371988 396.cindex "Debian" "information sources"
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397If you are using a Debian distribution of Exim, you will find information about
398Debian-specific features in the file
f89d2485 399&_/usr/share/doc/exim4-base/README.Debian_&.
9b371988 400The command &(man update-exim.conf)& is another source of Debian-specific
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401information.
402
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403.cindex "&_doc/NewStuff_&"
404.cindex "&_doc/ChangeLog_&"
405.cindex "change log"
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406As the program develops, there may be features in newer versions that have not
407yet made it into this document, which is updated only when the most significant
408digit of the fractional part of the version number changes. Specifications of
409new features that are not yet in this manual are placed in the file
9b371988 410&_doc/NewStuff_& in the Exim distribution.
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9b371988 412Some features may be classified as &"experimental"&. These may change
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413incompatibly while they are developing, or even be withdrawn. For this reason,
414they are not documented in this manual. Information about experimental features
9b371988 415can be found in the file &_doc/experimental.txt_&.
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416
417All changes to the program (whether new features, bug fixes, or other kinds of
9b371988 418change) are noted briefly in the file called &_doc/ChangeLog_&.
168e428f 419
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420.cindex "&_doc/spec.txt_&"
421This specification itself is available as an ASCII file in &_doc/spec.txt_& so
422that it can easily be searched with a text editor. Other files in the &_doc_&
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423directory are:
424
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425.table2 100pt
426.row &_OptionLists.txt_& "list of all options in alphabetical order"
427.row &_dbm.discuss.txt_& "discussion about DBM libraries"
428.row &_exim.8_& "a man page of Exim's command line options"
429.row &_experimental.txt_& "documentation of experimental features"
430.row &_filter.txt_& "specification of the filter language"
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431.row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
432.row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
433.endtable
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434
435The main specification and the specification of the filtering language are also
436available in other formats (HTML, PostScript, PDF, and Texinfo). Section
9b371988 437&<<SECTavail>>& below tells you how to get hold of these.
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438
439
440
f89d2485 441.section "FTP and web sites" "SECID2"
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442.cindex "web site"
443.cindex "FTP site"
068aaea8 444The primary site for Exim source distributions is currently the University of
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445Cambridge's FTP site, whose contents are described in &'Where to find the Exim
446distribution'& below. In addition, there is a web site and an FTP site at
447&%exim.org%&. These are now also hosted at the University of Cambridge. The
448&%exim.org%& site was previously hosted for a number of years by Energis
449Squared, formerly Planet Online Ltd, whose support I gratefully acknowledge.
450
451.cindex "wiki"
452.cindex "FAQ"
168e428f 453As well as Exim distribution tar files, the Exim web site contains a number of
f89d2485 454differently formatted versions of the documentation. A recent addition to the
7d0ab55c 455online information is the Exim wiki (&url(http://wiki.exim.org)),
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456which contains what used to be a separate FAQ, as well as various other
457examples, tips, and know-how that have been contributed by Exim users.
458
459.cindex Bugzilla
7d0ab55c 460An Exim Bugzilla exists at &url(http://bugs.exim.org). You can use
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461this to report bugs, and also to add items to the wish list. Please search
462first to check that you are not duplicating a previous entry.
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463
464
465
f89d2485 466.section "Mailing lists" "SECID3"
9b371988 467.cindex "mailing lists" "for Exim users"
f89d2485 468The following Exim mailing lists exist:
168e428f 469
9b371988 470.table2 140pt
d854d3a9 471.row &'exim-announce@exim.org'& "Moderated, low volume announcements list"
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472.row &'exim-users@exim.org'& "General discussion list"
473.row &'exim-dev@exim.org'& "Discussion of bugs, enhancements, etc."
d854d3a9 474.row &'exim-cvs@exim.org'& "Automated commit messages from the VCS"
9b371988 475.endtable
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476
477You can subscribe to these lists, change your existing subscriptions, and view
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478or search the archives via the mailing lists link on the Exim home page.
479.cindex "Debian" "mailing list for"
4f578862 480If you are using a Debian distribution of Exim, you may wish to subscribe to
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481the Debian-specific mailing list &'pkg-exim4-users@lists.alioth.debian.org'&
482via this web page:
483.display
484&url(http://lists.alioth.debian.org/mailman/listinfo/pkg-exim4-users)
485.endd
486Please ask Debian-specific questions on this list and not on the general Exim
487lists.
9b371988 488
f89d2485 489.section "Exim training" "SECID4"
9b371988 490.cindex "training courses"
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491Training courses in Cambridge (UK) used to be run annually by the author of
492Exim, before he retired. At the time of writing, there are no plans to run
493further Exim courses in Cambridge. However, if that changes, relevant
494information will be posted at &url(http://www-tus.csx.cam.ac.uk/courses/exim/).
168e428f 495
f89d2485 496.section "Bug reports" "SECID5"
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497.cindex "bug reports"
498.cindex "reporting bugs"
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499Reports of obvious bugs can be emailed to &'bugs@exim.org'& or reported
500via the Bugzilla (&url(http://bugs.exim.org)). However, if you are unsure
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501whether some behaviour is a bug or not, the best thing to do is to post a
502message to the &'exim-dev'& mailing list and have it discussed.
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503
504
505
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506.section "Where to find the Exim distribution" "SECTavail"
507.cindex "FTP site"
508.cindex "distribution" "ftp site"
168e428f 509The master ftp site for the Exim distribution is
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510.display
511&*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim*&
512.endd
168e428f 513This is mirrored by
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514.display
515&*ftp://ftp.exim.org/pub/exim*&
516.endd
517The file references that follow are relative to the &_exim_& directories at
518these sites. There are now quite a number of independent mirror sites around
519the world. Those that I know about are listed in the file called &_Mirrors_&.
520
521Within the &_exim_& directory there are subdirectories called &_exim3_& (for
522previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
523distributions), and &_Testing_& for testing versions. In the &_exim4_&
168e428f 524subdirectory, the current release can always be found in files called
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525.display
526&_exim-n.nn.tar.gz_&
527&_exim-n.nn.tar.bz2_&
528.endd
529where &'n.nn'& is the highest such version number in the directory. The two
168e428f 530files contain identical data; the only difference is the type of compression.
9b371988 531The &_.bz2_& file is usually a lot smaller than the &_.gz_& file.
168e428f 532
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533.cindex "distribution" "signing details"
534.cindex "distribution" "public key"
535.cindex "public key for signed distribution"
40167b05
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536.new
537The distributions will be PGP signed by an individual key of the Release
538Coordinator. This key will have a uid containing an email address in the
539&'exim.org'& domain and will have signatures from other people, including
540other Exim maintainers. We expect that the key will be in the "strong set" of
541PGP keys. There should be a trust path to that key from Nigel Metheringham's
542PGP key, a version of which can be found in the release directory in the file
543&_nigel-pubkey.asc_&. All keys used will be available in public keyserver pools,
544such as &'pool.sks-keyservers.net'&.
545
546At time of last update, releases were being made by Phil Pennock and signed with
547key &'0x403043153903637F'&, although that key is expected to be replaced in 2013.
548A trust path from Nigel's key to Phil's can be observed at
549&url(https://www.security.spodhuis.org/exim-trustpath).
550.wen
551
552The signatures for the tar bundles are in:
9b371988 553.display
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554&_exim-n.nn.tar.gz.asc_&
555&_exim-n.nn.tar.bz2.asc_&
9b371988 556.endd
168e428f 557For each released version, the log of changes is made separately available in a
9b371988 558separate file in the directory &_ChangeLogs_& so that it is possible to
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559find out what has changed without having to download the entire distribution.
560
9b371988 561.cindex "documentation" "available formats"
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562The main distribution contains ASCII versions of this specification and other
563documentation; other formats of the documents are available in separate files
9b371988
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564inside the &_exim4_& directory of the FTP site:
565.display
566&_exim-html-n.nn.tar.gz_&
567&_exim-pdf-n.nn.tar.gz_&
568&_exim-postscript-n.nn.tar.gz_&
569&_exim-texinfo-n.nn.tar.gz_&
570.endd
571These tar files contain only the &_doc_& directory, not the complete
572distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
168e428f 573
168e428f 574
f89d2485 575.section "Limitations" "SECID6"
9b371988
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576.ilist
577.cindex "limitations of Exim"
578.cindex "bang paths" "not handled by Exim"
579Exim is designed for use as an Internet MTA, and therefore handles addresses in
580RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
581simple two-component bang paths can be converted by a straightforward rewriting
582configuration. This restriction does not prevent Exim from being interfaced to
583UUCP as a transport mechanism, provided that domain addresses are used.
584.next
585.cindex "domainless addresses"
586.cindex "address" "without domain"
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587Exim insists that every address it handles has a domain attached. For incoming
588local messages, domainless addresses are automatically qualified with a
589configured domain value. Configuration options specify from which remote
590systems unqualified addresses are acceptable. These are then qualified on
591arrival.
9b371988
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592.next
593.cindex "transport" "external"
594.cindex "external transports"
595The only external transport mechanisms that are currently implemented are SMTP
596and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
168e428f 597transport is available, and there are facilities for writing messages to files
9b371988
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598and pipes, optionally in &'batched SMTP'& format; these facilities can be used
599to send messages to other transport mechanisms such as UUCP, provided they can
600handle domain-style addresses. Batched SMTP input is also catered for.
601.next
602Exim is not designed for storing mail for dial-in hosts. When the volumes of
603such mail are large, it is better to get the messages &"delivered"& into files
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604(that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
605other means.
9b371988
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606.next
607Although Exim does have basic facilities for scanning incoming messages, these
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608are not comprehensive enough to do full virus or spam scanning. Such operations
609are best carried out using additional specialized software packages. If you
610compile Exim with the content-scanning extension, straightforward interfaces to
611a number of common scanners are provided.
9b371988 612.endlist
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613
614
f89d2485 615.section "Run time configuration" "SECID7"
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616Exim's run time configuration is held in a single text file that is divided
617into a number of sections. The entries in this file consist of keywords and
618values, in the style of Smail 3 configuration files. A default configuration
619file which is suitable for simple online installations is provided in the
9b371988 620distribution, and is described in chapter &<<CHAPdefconfil>>& below.
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621
622
f89d2485 623.section "Calling interface" "SECID8"
9b371988 624.cindex "Sendmail compatibility" "command line interface"
168e428f 625Like many MTAs, Exim has adopted the Sendmail command line interface so that it
9b371988
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626can be a straight replacement for &_/usr/lib/sendmail_& or
627&_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
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628about Sendmail in order to run Exim. For actions other than sending messages,
629Sendmail-compatible options also exist, but those that produce output (for
9b371988 630example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
168e428f 631format. There are also some additional options that are compatible with Smail
9b371988 6323, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
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633documents all Exim's command line options. This information is automatically
634made into the man page that forms part of the Exim distribution.
635
636Control of messages on the queue can be done via certain privileged command
9b371988
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637line options. There is also an optional monitor program called &'eximon'&,
638which displays current information in an X window, and which contains a menu
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639interface to Exim's command line administration options.
640
641
642
f89d2485 643.section "Terminology" "SECID9"
9b371988
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644.cindex "terminology definitions"
645.cindex "body of message" "definition of"
646The &'body'& of a message is the actual data that the sender wants to transmit.
647It is the last part of a message, and is separated from the &'header'& (see
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648below) by a blank line.
649
9b371988 650.cindex "bounce message" "definition of"
168e428f 651When a message cannot be delivered, it is normally returned to the sender in a
9b371988
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652delivery failure message or a &"non-delivery report"& (NDR). The term
653&'bounce'& is commonly used for this action, and the error reports are often
654called &'bounce messages'&. This is a convenient shorthand for &"delivery
655failure error report"&. Such messages have an empty sender address in the
656message's &'envelope'& (see below) to ensure that they cannot themselves give
657rise to further bounce messages.
658
659The term &'default'& appears frequently in this manual. It is used to qualify a
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660value which is used in the absence of any setting in the configuration. It may
661also qualify an action which is taken unless a configuration setting specifies
662otherwise.
663
9b371988 664The term &'defer'& is used when the delivery of a message to a specific
168e428f 665destination cannot immediately take place for some reason (a remote host may be
9b371988 666down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
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667until a later time.
668
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669The word &'domain'& is sometimes used to mean all but the first component of a
670host's name. It is &'not'& used in that sense here, where it normally refers to
671the part of an email address following the @ sign.
168e428f 672
f89d2485 673.cindex "envelope, definition of"
9b371988
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674.cindex "sender" "definition of"
675A message in transit has an associated &'envelope'&, as well as a header and a
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676body. The envelope contains a sender address (to which bounce messages should
677be delivered), and any number of recipient addresses. References to the
678sender or the recipients of a message usually mean the addresses in the
679envelope. An MTA uses these addresses for delivery, and for returning bounce
680messages, not the addresses that appear in the header lines.
681
f89d2485 682.cindex "message" "header, definition of"
9b371988
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683.cindex "header section" "definition of"
684The &'header'& of a message is the first part of a message's text, consisting
685of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
686&'Subject:'&, etc. Long header lines can be split over several text lines by
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687indenting the continuations. The header is separated from the body by a blank
688line.
689
9b371988
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690.cindex "local part" "definition of"
691.cindex "domain" "definition of"
692The term &'local part'&, which is taken from RFC 2822, is used to refer to that
168e428f 693part of an email address that precedes the @ sign. The part that follows the
9b371988 694@ sign is called the &'domain'& or &'mail domain'&.
168e428f 695
9b371988 696.cindex "local delivery" "definition of"
f89d2485 697.cindex "remote delivery, definition of"
9b371988 698The terms &'local delivery'& and &'remote delivery'& are used to distinguish
168e428f 699delivery to a file or a pipe on the local host from delivery by SMTP over
068aaea8 700TCP/IP to another host. As far as Exim is concerned, all hosts other than the
9b371988 701host it is running on are &'remote'&.
168e428f 702
9b371988
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703.cindex "return path" "definition of"
704&'Return path'& is another name that is used for the sender address in a
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705message's envelope.
706
9b371988
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707.cindex "queue" "definition of"
708The term &'queue'& is used to refer to the set of messages awaiting delivery,
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709because this term is in widespread use in the context of MTAs. However, in
710Exim's case the reality is more like a pool than a queue, because there is
711normally no ordering of waiting messages.
712
9b371988
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713.cindex "queue runner" "definition of"
714The term &'queue runner'& is used to describe a process that scans the queue
168e428f 715and attempts to deliver those messages whose retry times have come. This term
9b371988 716is used by other MTAs, and also relates to the command &%runq%&, but in Exim
168e428f
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717the waiting messages are normally processed in an unpredictable order.
718
9b371988
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719.cindex "spool directory" "definition of"
720The term &'spool directory'& is used for a directory in which Exim keeps the
721messages on its queue &-- that is, those that it is in the process of
168e428f 722delivering. This should not be confused with the directory in which local
9b371988
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723mailboxes are stored, which is called a &"spool directory"& by some people. In
724the Exim documentation, &"spool"& is always used in the first sense.
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725
726
727
728
729
730
9b371988
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731. ////////////////////////////////////////////////////////////////////////////
732. ////////////////////////////////////////////////////////////////////////////
168e428f 733
f89d2485 734.chapter "Incorporated code" "CHID2"
9b371988
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735.cindex "incorporated code"
736.cindex "regular expressions" "library"
737.cindex "PCRE"
168e428f
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738A number of pieces of external code are included in the Exim distribution.
739
9b371988 740.ilist
210f147e
NM
741Regular expressions are supported in the main Exim program and in the
742Exim monitor using the freely-distributable PCRE library, copyright
40df1be3
TF
743&copy; University of Cambridge. The source to PCRE is no longer shipped with
744Exim, so you will need to use the version of PCRE shipped with your system,
745or obtain and install the full version of the library from
f89d2485 746&url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
9b371988 747.next
f89d2485 748.cindex "cdb" "acknowledgment"
168e428f
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749Support for the cdb (Constant DataBase) lookup method is provided by code
750contributed by Nigel Metheringham of (at the time he contributed it) Planet
9b371988
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751Online Ltd. The implementation is completely contained within the code of Exim.
752It does not link against an external cdb library. The code contains the
753following statements:
754
755.blockquote
756Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
757
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758This program is free software; you can redistribute it and/or modify it under
759the terms of the GNU General Public License as published by the Free Software
760Foundation; either version 2 of the License, or (at your option) any later
761version.
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762This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
763the spec and sample code for cdb can be obtained from
f89d2485
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764&url(http://www.pobox.com/~djb/cdb.html). This implementation borrows
765some code from Dan Bernstein's implementation (which has no license
766restrictions applied to it).
9b371988
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767.endblockquote
768.next
769.cindex "SPA authentication"
770.cindex "Samba project"
771.cindex "Microsoft Secure Password Authentication"
772Client support for Microsoft's &'Secure Password Authentication'& is provided
168e428f
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773by code contributed by Marc Prud'hommeaux. Server support was contributed by
774Tom Kistner. This includes code taken from the Samba project, which is released
775under the Gnu GPL.
9b371988
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776.next
777.cindex "Cyrus"
778.cindex "&'pwcheck'& daemon"
779.cindex "&'pwauthd'& daemon"
780Support for calling the Cyrus &'pwcheck'& and &'saslauthd'& daemons is provided
168e428f
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781by code taken from the Cyrus-SASL library and adapted by Alexander S.
782Sabourenkov. The permission notice appears below, in accordance with the
783conditions expressed therein.
9b371988
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784
785.blockquote
786Copyright &copy; 2001 Carnegie Mellon University. All rights reserved.
787
168e428f
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788Redistribution and use in source and binary forms, with or without
789modification, are permitted provided that the following conditions
790are met:
168e428f 791
9b371988
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792.olist
793Redistributions of source code must retain the above copyright
794notice, this list of conditions and the following disclaimer.
795.next
796Redistributions in binary form must reproduce the above copyright
168e428f
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797notice, this list of conditions and the following disclaimer in
798the documentation and/or other materials provided with the
799distribution.
9b371988
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800.next
801The name &"Carnegie Mellon University"& must not be used to
168e428f
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802endorse or promote products derived from this software without
803prior written permission. For permission or any other legal
804details, please contact
9b371988 805.display
068aaea8
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806 Office of Technology Transfer
807 Carnegie Mellon University
808 5000 Forbes Avenue
809 Pittsburgh, PA 15213-3890
810 (412) 268-4387, fax: (412) 268-7395
811 tech-transfer@andrew.cmu.edu
9b371988
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812.endd
813.next
814Redistributions of any form whatsoever must retain the following
168e428f 815acknowledgment:
9b371988
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816
817&"This product includes software developed by Computing Services
818at Carnegie Mellon University (&url(http://www.cmu.edu/computing/)."&
819
168e428f
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820CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
821THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
822AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
823FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
824WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
825AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
826OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
9b371988
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827.endlist
828.endblockquote
168e428f 829
9b371988 830.next
f89d2485 831.cindex "Exim monitor" "acknowledgment"
9b371988
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832.cindex "X-windows"
833.cindex "Athena"
168e428f
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834The Exim Monitor program, which is an X-Window application, includes
835modified versions of the Athena StripChart and TextPop widgets.
836This code is copyright by DEC and MIT, and their permission notice appears
837below, in accordance with the conditions expressed therein.
9b371988
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838
839.blockquote
168e428f
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840Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
841and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
9b371988 842
168e428f 843All Rights Reserved
9b371988 844
168e428f
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845Permission to use, copy, modify, and distribute this software and its
846documentation for any purpose and without fee is hereby granted,
847provided that the above copyright notice appear in all copies and that
848both that copyright notice and this permission notice appear in
849supporting documentation, and that the names of Digital or MIT not be
850used in advertising or publicity pertaining to distribution of the
851software without specific, written prior permission.
9b371988 852
168e428f
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853DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
854ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
855DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
856ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
857WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
858ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
859SOFTWARE.
9b371988 860.endblockquote
168e428f 861
9b371988
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862.next
863Many people have contributed code fragments, some large, some small, that were
168e428f 864not covered by any specific licence requirements. It is assumed that the
f89d2485 865contributors are happy to see their code incorporated into Exim under the GPL.
9b371988 866.endlist
168e428f
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867
868
869
870
871
9b371988
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872. ////////////////////////////////////////////////////////////////////////////
873. ////////////////////////////////////////////////////////////////////////////
168e428f 874
f89d2485 875.chapter "How Exim receives and delivers mail" "CHID11" &&&
9b371988 876 "Receiving and delivering mail"
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877
878
f89d2485 879.section "Overall philosophy" "SECID10"
9b371988 880.cindex "design philosophy"
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881Exim is designed to work efficiently on systems that are permanently connected
882to the Internet and are handling a general mix of mail. In such circumstances,
883most messages can be delivered immediately. Consequently, Exim does not
884maintain independent queues of messages for specific domains or hosts, though
885it does try to send several messages in a single SMTP connection after a host
886has been down, and it also maintains per-host retry information.
887
888
f89d2485 889.section "Policy control" "SECID11"
9b371988 890.cindex "policy control" "overview"
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891Policy controls are now an important feature of MTAs that are connected to the
892Internet. Perhaps their most important job is to stop MTAs being abused as
9b371988
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893&"open relays"& by misguided individuals who send out vast amounts of
894unsolicited junk, and want to disguise its source. Exim provides flexible
895facilities for specifying policy controls on incoming mail:
168e428f 896
9b371988
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897.ilist
898.cindex "&ACL;" "introduction"
168e428f 899Exim 4 (unlike previous versions of Exim) implements policy controls on
9b371988 900incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
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901series of statements that may either grant or deny access. ACLs can be used at
902several places in the SMTP dialogue while receiving a message from a remote
9b371988
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903host. However, the most common places are after each RCPT command, and at the
904very end of the message. The sysadmin can specify conditions for accepting or
905rejecting individual recipients or the entire message, respectively, at these
906two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
168e428f 907error code.
9b371988
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908.next
909An ACL is also available for locally generated, non-SMTP messages. In this
168e428f 910case, the only available actions are to accept or deny the entire message.
9b371988
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911.next
912When Exim is compiled with the content-scanning extension, facilities are
168e428f
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913provided in the ACL mechanism for passing the message to external virus and/or
914spam scanning software. The result of such a scan is passed back to the ACL,
915which can then use it to decide what to do with the message.
9b371988
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916.next
917When a message has been received, either from a remote host or from the local
f89d2485 918host, but before the final acknowledgment has been sent, a locally supplied C
9b371988
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919function called &[local_scan()]& can be run to inspect the message and decide
920whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
921is accepted, the list of recipients can be modified by the function.
922.next
923Using the &[local_scan()]& mechanism is another way of calling external scanner
924software. The &%SA-Exim%& add-on package works this way. It does not require
925Exim to be compiled with the content-scanning extension.
926.next
927After a message has been accepted, a further checking mechanism is available in
928the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
929runs at the start of every delivery process.
930.endlist
931
932
933
f89d2485 934.section "User filters" "SECID12"
9b371988
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935.cindex "filter" "introduction"
936.cindex "Sieve filter"
168e428f 937In a conventional Exim configuration, users are able to run private filters by
9b371988
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938setting up appropriate &_.forward_& files in their home directories. See
939chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
940configuration needed to support this, and the separate document entitled
941&'Exim's interfaces to mail filtering'& for user details. Two different kinds
942of filtering are available:
943
944.ilist
945Sieve filters are written in the standard filtering language that is defined
168e428f 946by RFC 3028.
9b371988
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947.next
948Exim filters are written in a syntax that is unique to Exim, but which is more
168e428f 949powerful than Sieve, which it pre-dates.
9b371988 950.endlist
168e428f
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951
952User filters are run as part of the routing process, described below.
953
954
955
9b371988
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956.section "Message identification" "SECTmessiden"
957.cindex "message ids" "details of format"
958.cindex "format" "of message id"
959.cindex "id of message"
960.cindex "base62"
961.cindex "base36"
962.cindex "Darwin"
963.cindex "Cygwin"
964Every message handled by Exim is given a &'message id'& which is sixteen
168e428f 965characters long. It is divided into three parts, separated by hyphens, for
9b371988 966example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
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967normally encoding numbers in base 62. However, in the Darwin operating
968system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
969(avoiding the use of lower case letters) is used instead, because the message
970id is used to construct file names, and the names of files in those systems are
068aaea8 971not always case-sensitive.
168e428f 972
9b371988 973.cindex "pid (process id)" "re-use of"
168e428f
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974The detail of the contents of the message id have changed as Exim has evolved.
975Earlier versions relied on the operating system not re-using a process id (pid)
976within one second. On modern operating systems, this assumption can no longer
977be made, so the algorithm had to be changed. To retain backward compatibility,
978the format of the message id was retained, which is why the following rules are
979somewhat eccentric:
980
9b371988
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981.ilist
982The first six characters of the message id are the time at which the message
168e428f
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983started to be received, to a granularity of one second. That is, this field
984contains the number of seconds since the start of the epoch (the normal Unix
985way of representing the date and time of day).
9b371988
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986.next
987After the first hyphen, the next six characters are the id of the process that
168e428f 988received the message.
9b371988
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989.next
990There are two different possibilities for the final two characters:
991.olist
0a4e3112 992.oindex "&%localhost_number%&"
9b371988 993If &%localhost_number%& is not set, this value is the fractional part of the
168e428f
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994time of reception, normally in units of 1/2000 of a second, but for systems
995that must use base 36 instead of base 62 (because of case-insensitive file
996systems), the units are 1/1000 of a second.
9b371988
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997.next
998If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
168e428f
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999the fractional part of the time, which in this case is in units of 1/200
1000(1/100) of a second.
9b371988
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1001.endlist
1002.endlist
168e428f
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1003
1004After a message has been received, Exim waits for the clock to tick at the
1005appropriate resolution before proceeding, so that if another message is
1006received by the same process, or by another process with the same (re-used)
1007pid, it is guaranteed that the time will be different. In most cases, the clock
1008will already have ticked while the message was being received.
1009
1010
f89d2485 1011.section "Receiving mail" "SECID13"
9b371988
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1012.cindex "receiving mail"
1013.cindex "message" "reception"
068aaea8
PH
1014The only way Exim can receive mail from another host is using SMTP over
1015TCP/IP, in which case the sender and recipient addresses are transferred using
168e428f
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1016SMTP commands. However, from a locally running process (such as a user's MUA),
1017there are several possibilities:
1018
9b371988
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1019.ilist
1020If the process runs Exim with the &%-bm%& option, the message is read
168e428f 1021non-interactively (usually via a pipe), with the recipients taken from the
9b371988
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1022command line, or from the body of the message if &%-t%& is also used.
1023.next
1024If the process runs Exim with the &%-bS%& option, the message is also read
168e428f
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1025non-interactively, but in this case the recipients are listed at the start of
1026the message in a series of SMTP RCPT commands, terminated by a DATA
9b371988 1027command. This is so-called &"batch SMTP"& format,
168e428f
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1028but it isn't really SMTP. The SMTP commands are just another way of passing
1029envelope addresses in a non-interactive submission.
9b371988
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1030.next
1031If the process runs Exim with the &%-bs%& option, the message is read
168e428f
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1032interactively, using the SMTP protocol. A two-way pipe is normally used for
1033passing data between the local process and the Exim process.
9b371988 1034This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
168e428f 1035example, the ACLs for SMTP commands are used for this form of submission.
9b371988
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1036.next
1037A local process may also make a TCP/IP call to the host's loopback address
168e428f
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1038(127.0.0.1) or any other of its IP addresses. When receiving messages, Exim
1039does not treat the loopback address specially. It treats all such connections
1040in the same way as connections from other hosts.
9b371988 1041.endlist
168e428f
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1042
1043
f89d2485 1044.cindex "message sender, constructed by Exim"
9b371988 1045.cindex "sender" "constructed by Exim"
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1046In the three cases that do not involve TCP/IP, the sender address is
1047constructed from the login name of the user that called Exim and a default
9b371988 1048qualification domain (which can be set by the &%qualify_domain%& configuration
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1049option). For local or batch SMTP, a sender address that is passed using the
1050SMTP MAIL command is ignored. However, the system administrator may allow
9b371988 1051certain users (&"trusted users"&) to specify a different sender address
168e428f 1052unconditionally, or all users to specify certain forms of different sender
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1053address. The &%-f%& option or the SMTP MAIL command is used to specify these
1054different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1055users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
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1056users to change sender addresses.
1057
1058Messages received by either of the non-interactive mechanisms are subject to
1059checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1060(either over TCP/IP, or interacting with a local process) can be checked by a
1061number of ACLs that operate at different times during the SMTP session. Either
1062individual recipients, or the entire message, can be rejected if local policy
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1063requirements are not met. The &[local_scan()]& function (see chapter
1064&<<CHAPlocalscan>>&) is run for all incoming messages.
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1065
1066Exim can be configured not to start a delivery process when a message is
1067received; this can be unconditional, or depend on the number of incoming SMTP
1068connections or the system load. In these situations, new messages wait on the
1069queue until a queue runner process picks them up. However, in standard
1070configurations under normal conditions, delivery is started as soon as a
1071message is received.
1072
1073
1074
1075
1076
f89d2485 1077.section "Handling an incoming message" "SECID14"
9b371988
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1078.cindex "spool directory" "files that hold a message"
1079.cindex "file" "how a message is held"
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1080When Exim accepts a message, it writes two files in its spool directory. The
1081first contains the envelope information, the current status of the message, and
1082the header lines, and the second contains the body of the message. The names of
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1083the two spool files consist of the message id, followed by &`-H`& for the
1084file containing the envelope and header, and &`-D`& for the data file.
168e428f 1085
9b371988 1086.cindex "spool directory" "&_input_& sub-directory"
168e428f 1087By default all these message files are held in a single directory called
9b371988 1088&_input_& inside the general Exim spool directory. Some operating systems do
c0712871 1089not perform very well if the number of files in a directory gets large; to
9b371988 1090improve performance in such cases, the &%split_spool_directory%& option can be
168e428f 1091used. This causes Exim to split up the input files into 62 sub-directories
db9452a9 1092whose names are single letters or digits. When this is done, the queue is
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1093processed one sub-directory at a time instead of all at once, which can improve
1094overall performance even when there are not enough files in each directory to
db9452a9 1095affect file system performance.
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1096
1097The envelope information consists of the address of the message's sender and
1098the addresses of the recipients. This information is entirely separate from
1099any addresses contained in the header lines. The status of the message includes
1100a list of recipients who have already received the message. The format of the
9b371988 1101first spool file is described in chapter &<<CHAPspool>>&.
168e428f 1102
9b371988 1103.cindex "rewriting" "addresses"
168e428f 1104Address rewriting that is specified in the rewrite section of the configuration
9b371988 1105(see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
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1106both in the header lines and the envelope, at the time the message is accepted.
1107If during the course of delivery additional addresses are generated (for
1108example, via aliasing), these new addresses are rewritten as soon as they are
1109generated. At the time a message is actually delivered (transported) further
1110rewriting can take place; because this is a transport option, it can be
1111different for different forms of delivery. It is also possible to specify the
1112addition or removal of certain header lines at the time the message is
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1113delivered (see chapters &<<CHAProutergeneric>>& and
1114&<<CHAPtransportgeneric>>&).
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1115
1116
1117
f89d2485 1118.section "Life of a message" "SECID15"
9b371988
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1119.cindex "message" "life of"
1120.cindex "message" "frozen"
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1121A message remains in the spool directory until it is completely delivered to
1122its recipients or to an error address, or until it is deleted by an
1123administrator or by the user who originally created it. In cases when delivery
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1124cannot proceed &-- for example, when a message can neither be delivered to its
1125recipients nor returned to its sender, the message is marked &"frozen"& on the
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1126spool, and no more deliveries are attempted.
1127
9b371988
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1128.cindex "frozen messages" "thawing"
1129.cindex "message" "thawing frozen"
1130An administrator can &"thaw"& such messages when the problem has been
1131corrected, and can also freeze individual messages by hand if necessary. In
1132addition, an administrator can force a delivery error, causing a bounce message
1133to be sent.
1134
0a4e3112
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1135.oindex "&%timeout_frozen_after%&"
1136.oindex "&%ignore_bounce_errors_after%&"
9b371988
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1137There are options called &%ignore_bounce_errors_after%& and
1138&%timeout_frozen_after%&, which discard frozen messages after a certain time.
068aaea8 1139The first applies only to frozen bounces, the second to any frozen messages.
168e428f 1140
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1141.cindex "message" "log file for"
1142.cindex "log" "file for each message"
168e428f 1143While Exim is working on a message, it writes information about each delivery
068aaea8 1144attempt to its main log file. This includes successful, unsuccessful, and
9b371988
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1145delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1146lines are also written to a separate &'message log'& file for each message.
1147These logs are solely for the benefit of the administrator, and are normally
1148deleted along with the spool files when processing of a message is complete.
168e428f 1149The use of individual message logs can be disabled by setting
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1150&%no_message_logs%&; this might give an improvement in performance on very busy
1151systems.
168e428f 1152
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1153.cindex "journal file"
1154.cindex "file" "journal"
168e428f
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1155All the information Exim itself needs to set up a delivery is kept in the first
1156spool file, along with the header lines. When a successful delivery occurs, the
1157address is immediately written at the end of a journal file, whose name is the
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1158message id followed by &`-J`&. At the end of a delivery run, if there are some
1159addresses left to be tried again later, the first spool file (the &`-H`& file)
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1160is updated to indicate which these are, and the journal file is then deleted.
1161Updating the spool file is done by writing a new file and renaming it, to
1162minimize the possibility of data loss.
1163
1164Should the system or the program crash after a successful delivery but before
1165the spool file has been updated, the journal is left lying around. The next
1166time Exim attempts to deliver the message, it reads the journal file and
1167updates the spool file before proceeding. This minimizes the chances of double
1168deliveries caused by crashes.
1169
1170
1171
9b371988
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1172.section "Processing an address for delivery" "SECTprocaddress"
1173.cindex "drivers" "definition of"
1174.cindex "router" "definition of"
1175.cindex "transport" "definition of"
1176The main delivery processing elements of Exim are called &'routers'& and
1177&'transports'&, and collectively these are known as &'drivers'&. Code for a
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1178number of them is provided in the source distribution, and compile-time options
1179specify which ones are included in the binary. Run time options specify which
1180ones are actually used for delivering messages.
1181
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1182.cindex "drivers" "instance definition"
1183Each driver that is specified in the run time configuration is an &'instance'&
168e428f 1184of that particular driver type. Multiple instances are allowed; for example,
9b371988 1185you can set up several different &(smtp)& transports, each with different
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1186option values that might specify different ports or different timeouts. Each
1187instance has its own identifying name. In what follows we will normally use the
1188instance name when discussing one particular instance (that is, one specific
1189configuration of the driver), and the generic driver name when discussing
1190the driver's features in general.
1191
9b371988 1192A &'router'& is a driver that operates on an address, either determining how
068aaea8 1193its delivery should happen, by assigning it to a specific transport, or
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1194converting the address into one or more new addresses (for example, via an
1195alias file). A router may also explicitly choose to fail an address, causing it
1196to be bounced.
1197
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1198A &'transport'& is a driver that transmits a copy of the message from Exim's
1199spool to some destination. There are two kinds of transport: for a &'local'&
168e428f 1200transport, the destination is a file or a pipe on the local host, whereas for a
9b371988 1201&'remote'& transport the destination is some other host. A message is passed
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1202to a specific transport as a result of successful routing. If a message has
1203several recipients, it may be passed to a number of different transports.
1204
9b371988 1205.cindex "preconditions" "definition of"
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1206An address is processed by passing it to each configured router instance in
1207turn, subject to certain preconditions, until a router accepts the address or
1208specifies that it should be bounced. We will describe this process in more
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1209detail shortly. First, as a simple example, we consider how each recipient
1210address in a message is processed in a small configuration of three routers.
168e428f 1211
068aaea8 1212To make this a more concrete example, it is described in terms of some actual
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1213routers, but remember, this is only an example. You can configure Exim's
1214routers in many different ways, and there may be any number of routers in a
1215configuration.
1216
1217The first router that is specified in a configuration is often one that handles
1218addresses in domains that are not recognized specially by the local host. These
1219are typically addresses for arbitrary domains on the Internet. A precondition
1220is set up which looks for the special domains known to the host (for example,
9b371988 1221its own domain name), and the router is run for addresses that do &'not'&
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1222match. Typically, this is a router that looks up domains in the DNS in order to
1223find the hosts to which this address routes. If it succeeds, the address is
068aaea8 1224assigned to a suitable SMTP transport; if it does not succeed, the router is
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1225configured to fail the address.
1226
068aaea8 1227The second router is reached only when the domain is recognized as one that
9b371988 1228&"belongs"& to the local host. This router does redirection &-- also known as
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1229aliasing and forwarding. When it generates one or more new addresses from the
1230original, each of them is routed independently from the start. Otherwise, the
1231router may cause an address to fail, or it may simply decline to handle the
1232address, in which case the address is passed to the next router.
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1233
1234The final router in many configurations is one that checks to see if the
1235address belongs to a local mailbox. The precondition may involve a check to
1236see if the local part is the name of a login account, or it may look up the
1237local part in a file or a database. If its preconditions are not met, or if
1238the router declines, we have reached the end of the routers. When this happens,
1239the address is bounced.
1240
1241
1242
f89d2485 1243.section "Processing an address for verification" "SECID16"
9b371988
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1244.cindex "router" "for verification"
1245.cindex "verifying address" "overview"
168e428f 1246As well as being used to decide how to deliver to an address, Exim's routers
9b371988 1247are also used for &'address verification'&. Verification can be requested as
168e428f 1248one of the checks to be performed in an ACL for incoming messages, on both
9b371988
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1249sender and recipient addresses, and it can be tested using the &%-bv%& and
1250&%-bvs%& command line options.
168e428f 1251
9b371988 1252When an address is being verified, the routers are run in &"verify mode"&. This
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1253does not affect the way the routers work, but it is a state that can be
1254detected. By this means, a router can be skipped or made to behave differently
1255when verifying. A common example is a configuration in which the first router
1256sends all messages to a message-scanning program, unless they have been
1257previously scanned. Thus, the first router accepts all addresses without any
9b371988 1258checking, making it useless for verifying. Normally, the &%no_verify%& option
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1259would be set for such a router, causing it to be skipped in verify mode.
1260
1261
1262
1263
9b371988
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1264.section "Running an individual router" "SECTrunindrou"
1265.cindex "router" "running details"
1266.cindex "preconditions" "checking"
1267.cindex "router" "result of running"
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1268As explained in the example above, a number of preconditions are checked before
1269running a router. If any are not met, the router is skipped, and the address is
9b371988 1270passed to the next router. When all the preconditions on a router &'are'& met,
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1271the router is run. What happens next depends on the outcome, which is one of
1272the following:
1273
9b371988
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1274.ilist
1275&'accept'&: The router accepts the address, and either assigns it to a
1276transport, or generates one or more &"child"& addresses. Processing the
1277original address ceases,
0a4e3112 1278.oindex "&%unseen%&"
9b371988 1279unless the &%unseen%& option is set on the router. This option
168e428f 1280can be used to set up multiple deliveries with different routing (for example,
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1281for keeping archive copies of messages). When &%unseen%& is set, the address is
1282passed to the next router. Normally, however, an &'accept'& return marks the
168e428f 1283end of routing.
9b371988 1284
068aaea8
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1285Any child addresses generated by the router are processed independently,
1286starting with the first router by default. It is possible to change this by
9b371988
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1287setting the &%redirect_router%& option to specify which router to start at for
1288child addresses. Unlike &%pass_router%& (see below) the router specified by
1289&%redirect_router%& may be anywhere in the router configuration.
1290.next
1291&'pass'&: The router recognizes the address, but cannot handle it itself. It
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1292requests that the address be passed to another router. By default the address
1293is passed to the next router, but this can be changed by setting the
9b371988 1294&%pass_router%& option. However, (unlike &%redirect_router%&) the named router
168e428f 1295must be below the current router (to avoid loops).
9b371988
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1296.next
1297&'decline'&: The router declines to accept the address because it does not
168e428f 1298recognize it at all. By default, the address is passed to the next router, but
9b371988
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1299this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1300set, all the remaining routers are skipped. In effect, &%no_more%& converts
1301&'decline'& into &'fail'&.
1302.next
1303&'fail'&: The router determines that the address should fail, and queues it for
168e428f 1304the generation of a bounce message. There is no further processing of the
9b371988
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1305original address unless &%unseen%& is set on the router.
1306.next
1307&'defer'&: The router cannot handle the address at the present time. (A
068aaea8
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1308database may be offline, or a DNS lookup may have timed out.) No further
1309processing of the address happens in this delivery attempt. It is tried again
1310next time the message is considered for delivery.
9b371988
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1311.next
1312&'error'&: There is some error in the router (for example, a syntax error in
168e428f 1313its configuration). The action is as for defer.
9b371988 1314.endlist
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1315
1316If an address reaches the end of the routers without having been accepted by
068aaea8 1317any of them, it is bounced as unrouteable. The default error message in this
9b371988
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1318situation is &"unrouteable address"&, but you can set your own message by
1319making use of the &%cannot_route_message%& option. This can be set for any
1320router; the value from the last router that &"saw"& the address is used.
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1321
1322Sometimes while routing you want to fail a delivery when some conditions are
1323met but others are not, instead of passing the address on for further routing.
1324You can do this by having a second router that explicitly fails the delivery
9b371988 1325when the relevant conditions are met. The &(redirect)& router has a &"fail"&
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1326facility for this purpose.
1327
1328
f89d2485 1329.section "Duplicate addresses" "SECID17"
9b371988 1330.cindex "case of local parts"
f89d2485 1331.cindex "address duplicate, discarding"
db9452a9 1332.cindex "duplicate addresses"
068aaea8
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1333Once routing is complete, Exim scans the addresses that are assigned to local
1334and remote transports, and discards any duplicates that it finds. During this
3cb1b51e 1335check, local parts are treated as case-sensitive. This happens only when
db9452a9 1336actually delivering a message; when testing routers with &%-bt%&, all the
3cb1b51e 1337routed addresses are shown.
db9452a9 1338
068aaea8 1339
168e428f 1340
9b371988 1341.section "Router preconditions" "SECTrouprecon"
f89d2485 1342.cindex "router" "preconditions, order of processing"
9b371988 1343.cindex "preconditions" "order of processing"
168e428f
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1344The preconditions that are tested for each router are listed below, in the
1345order in which they are tested. The individual configuration options are
9b371988 1346described in more detail in chapter &<<CHAProutergeneric>>&.
168e428f 1347
9b371988
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1348.ilist
1349The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
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1350the local parts handled by the router may or must have certain prefixes and/or
1351suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1352skipped. These conditions are tested first. When an affix is present, it is
1353removed from the local part before further processing, including the evaluation
1354of any other conditions.
9b371988
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1355.next
1356Routers can be designated for use only when not verifying an address, that is,
168e428f 1357only when routing it for delivery (or testing its delivery routing). If the
9b371988 1358&%verify%& option is set false, the router is skipped when Exim is verifying an
168e428f 1359address.
9b371988
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1360Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1361&%verify_recipient%&, which independently control the use of the router for
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1362sender and recipient verification. You can set these options directly if
1363you want a router to be used for only one type of verification.
5b0cf788
JH
1364Note that cutthrough delivery is classed as a recipient verification
1365for this purpose.
9b371988
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1366.next
1367If the &%address_test%& option is set false, the router is skipped when Exim is
1368run with the &%-bt%& option to test an address routing. This can be helpful
1369when the first router sends all new messages to a scanner of some sort; it
1370makes it possible to use &%-bt%& to test subsequent delivery routing without
1371having to simulate the effect of the scanner.
1372.next
1373Routers can be designated for use only when verifying an address, as
1374opposed to routing it for delivery. The &%verify_only%& option controls this.
5b0cf788 1375Again, cutthrough delibery counts as a verification.
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1376.next
1377Individual routers can be explicitly skipped when running the routers to
1378check an address given in the SMTP EXPN command (see the &%expn%& option).
1379.next
1380If the &%domains%& option is set, the domain of the address must be in the set
068aaea8 1381of domains that it defines.
9b371988 1382.next
f89d2485
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1383.vindex "&$local_part_prefix$&"
1384.vindex "&$local_part$&"
1385.vindex "&$local_part_suffix$&"
9b371988
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1386If the &%local_parts%& option is set, the local part of the address must be in
1387the set of local parts that it defines. If &%local_part_prefix%& or
1388&%local_part_suffix%& is in use, the prefix or suffix is removed from the local
168e428f 1389part before this check. If you want to do precondition tests on local parts
9b371988
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1390that include affixes, you can do so by using a &%condition%& option (see below)
1391that uses the variables &$local_part$&, &$local_part_prefix$&, and
1392&$local_part_suffix$& as necessary.
1393.next
f89d2485
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1394.vindex "&$local_user_uid$&"
1395.vindex "&$local_user_gid$&"
1396.vindex "&$home$&"
9b371988 1397If the &%check_local_user%& option is set, the local part must be the name of
068aaea8 1398an account on the local host. If this check succeeds, the uid and gid of the
9b371988
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1399local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1400user's home directory is placed in &$home$&; these values can be used in the
1401remaining preconditions.
1402.next
1403If the &%router_home_directory%& option is set, it is expanded at this point,
1404because it overrides the value of &$home$&. If this expansion were left till
1405later, the value of &$home$& as set by &%check_local_user%& would be used in
1406subsequent tests. Having two different values of &$home$& in the same router
168e428f 1407could lead to confusion.
9b371988
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1408.next
1409If the &%senders%& option is set, the envelope sender address must be in the
1410set of addresses that it defines.
1411.next
1412If the &%require_files%& option is set, the existence or non-existence of
168e428f 1413specified files is tested.
9b371988
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1414.next
1415.cindex "customizing" "precondition"
1416If the &%condition%& option is set, it is evaluated and tested. This option
1417uses an expanded string to allow you to set up your own custom preconditions.
1418Expanded strings are described in chapter &<<CHAPexpand>>&.
1419.endlist
168e428f 1420
168e428f 1421
9b371988
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1422Note that &%require_files%& comes near the end of the list, so you cannot use
1423it to check for the existence of a file in which to lookup up a domain, local
168e428f 1424part, or sender. However, as these options are all expanded, you can use the
9b371988
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1425&%exists%& expansion condition to make such tests within each condition. The
1426&%require_files%& option is intended for checking files that the router may be
168e428f 1427going to use internally, or which are needed by a specific transport (for
9b371988 1428example, &_.procmailrc_&).
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1429
1430
1431
f89d2485 1432.section "Delivery in detail" "SECID18"
9b371988 1433.cindex "delivery" "in detail"
168e428f
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1434When a message is to be delivered, the sequence of events is as follows:
1435
9b371988
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1436.ilist
1437If a system-wide filter file is specified, the message is passed to it. The
168e428f
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1438filter may add recipients to the message, replace the recipients, discard the
1439message, cause a new message to be generated, or cause the message delivery to
1440fail. The format of the system filter file is the same as for Exim user filter
9b371988
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1441files, described in the separate document entitled &'Exim's interfaces to mail
1442filtering'&.
1443.cindex "Sieve filter" "not available for system filter"
1444(&*Note*&: Sieve cannot be used for system filter files.)
1445
1446Some additional features are available in system filters &-- see chapter
1447&<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
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1448filter only once per delivery attempt, however many recipients it has. However,
1449if there are several delivery attempts because one or more addresses could not
1450be immediately delivered, the system filter is run each time. The filter
9b371988 1451condition &%first_delivery%& can be used to detect the first run of the system
168e428f 1452filter.
9b371988
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1453.next
1454Each recipient address is offered to each configured router in turn, subject to
1455its preconditions, until one is able to handle it. If no router can handle the
1456address, that is, if they all decline, the address is failed. Because routers
1457can be targeted at particular domains, several locally handled domains can be
1458processed entirely independently of each other.
1459.next
1460.cindex "routing" "loops in"
1461.cindex "loop" "while routing"
1462A router that accepts an address may assign it to a local or a remote
1463transport. However, the transport is not run at this time. Instead, the address
1464is placed on a list for the particular transport, which will be run later.
068aaea8
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1465Alternatively, the router may generate one or more new addresses (typically
1466from alias, forward, or filter files). New addresses are fed back into this
1467process from the top, but in order to avoid loops, a router ignores any address
1468which has an identically-named ancestor that was processed by itself.
9b371988
PH
1469.next
1470When all the routing has been done, addresses that have been successfully
168e428f
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1471handled are passed to their assigned transports. When local transports are
1472doing real local deliveries, they handle only one address at a time, but if a
1473local transport is being used as a pseudo-remote transport (for example, to
1474collect batched SMTP messages for transmission by some other means) multiple
1475addresses can be handled. Remote transports can always handle more than one
1476address at a time, but can be configured not to do so, or to restrict multiple
1477addresses to the same domain.
9b371988
PH
1478.next
1479Each local delivery to a file or a pipe runs in a separate process under a
168e428f
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1480non-privileged uid, and these deliveries are run one at a time. Remote
1481deliveries also run in separate processes, normally under a uid that is private
9b371988 1482to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
168e428f 1483run in parallel. The maximum number of simultaneous remote deliveries for any
9b371988 1484one message is set by the &%remote_max_parallel%& option.
168e428f
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1485The order in which deliveries are done is not defined, except that all local
1486deliveries happen before any remote deliveries.
9b371988
PH
1487.next
1488.cindex "queue runner"
168e428f
PH
1489When it encounters a local delivery during a queue run, Exim checks its retry
1490database to see if there has been a previous temporary delivery failure for the
1491address before running the local transport. If there was a previous failure,
1492Exim does not attempt a new delivery until the retry time for the address is
1493reached. However, this happens only for delivery attempts that are part of a
1494queue run. Local deliveries are always attempted when delivery immediately
1495follows message reception, even if retry times are set for them. This makes for
1496better behaviour if one particular message is causing problems (for example,
1497causing quota overflow, or provoking an error in a filter file).
9b371988
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1498.next
1499.cindex "delivery" "retry in remote transports"
168e428f
PH
1500Remote transports do their own retry handling, since an address may be
1501deliverable to one of a number of hosts, each of which may have a different
1502retry time. If there have been previous temporary failures and no host has
1503reached its retry time, no delivery is attempted, whether in a queue run or
9b371988
PH
1504not. See chapter &<<CHAPretry>>& for details of retry strategies.
1505.next
1506If there were any permanent errors, a bounce message is returned to an
168e428f
PH
1507appropriate address (the sender in the common case), with details of the error
1508for each failing address. Exim can be configured to send copies of bounce
1509messages to other addresses.
9b371988
PH
1510.next
1511.cindex "delivery" "deferral"
168e428f
PH
1512If one or more addresses suffered a temporary failure, the message is left on
1513the queue, to be tried again later. Delivery of these addresses is said to be
9b371988
PH
1514&'deferred'&.
1515.next
1516When all the recipient addresses have either been delivered or bounced,
168e428f
PH
1517handling of the message is complete. The spool files and message log are
1518deleted, though the message log can optionally be preserved if required.
9b371988 1519.endlist
168e428f
PH
1520
1521
1522
1523
f89d2485 1524.section "Retry mechanism" "SECID19"
9b371988
PH
1525.cindex "delivery" "retry mechanism"
1526.cindex "retry" "description of mechanism"
1527.cindex "queue runner"
168e428f
PH
1528Exim's mechanism for retrying messages that fail to get delivered at the first
1529attempt is the queue runner process. You must either run an Exim daemon that
9b371988
PH
1530uses the &%-q%& option with a time interval to start queue runners at regular
1531intervals, or use some other means (such as &'cron'&) to start them. If you do
168e428f
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1532not arrange for queue runners to be run, messages that fail temporarily at the
1533first attempt will remain on your queue for ever. A queue runner process works
068aaea8 1534its way through the queue, one message at a time, trying each delivery that has
168e428f
PH
1535passed its retry time.
1536You can run several queue runners at once.
1537
1538Exim uses a set of configured rules to determine when next to retry the failing
9b371988
PH
1539address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1540should give up trying to deliver to the address, at which point it generates a
1541bounce message. If no retry rules are set for a particular host, address, and
1542error combination, no retries are attempted, and temporary errors are treated
1543as permanent.
168e428f
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1544
1545
1546
f89d2485 1547.section "Temporary delivery failure" "SECID20"
9b371988 1548.cindex "delivery" "temporary failure"
168e428f
PH
1549There are many reasons why a message may not be immediately deliverable to a
1550particular address. Failure to connect to a remote machine (because it, or the
1551connection to it, is down) is one of the most common. Temporary failures may be
1552detected during routing as well as during the transport stage of delivery.
1553Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1554is on a file system where the user is over quota. Exim can be configured to
1555impose its own quotas on local mailboxes; where system quotas are set they will
1556also apply.
1557
1558If a host is unreachable for a period of time, a number of messages may be
1559waiting for it by the time it recovers, and sending them in a single SMTP
1560connection is clearly beneficial. Whenever a delivery to a remote host is
1561deferred,
9b371988 1562.cindex "hints database"
168e428f
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1563Exim makes a note in its hints database, and whenever a successful
1564SMTP delivery has happened, it looks to see if any other messages are waiting
1565for the same host. If any are found, they are sent over the same SMTP
1566connection, subject to a configuration limit as to the maximum number in any
1567one connection.
168e428f
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1568
1569
1570
f89d2485 1571.section "Permanent delivery failure" "SECID21"
9b371988
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1572.cindex "delivery" "permanent failure"
1573.cindex "bounce message" "when generated"
168e428f
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1574When a message cannot be delivered to some or all of its intended recipients, a
1575bounce message is generated. Temporary delivery failures turn into permanent
1576errors when their timeout expires. All the addresses that fail in a given
1577delivery attempt are listed in a single message. If the original message has
1578many recipients, it is possible for some addresses to fail in one delivery
1579attempt and others to fail subsequently, giving rise to more than one bounce
1580message. The wording of bounce messages can be customized by the administrator.
9b371988 1581See chapter &<<CHAPemsgcust>>& for details.
168e428f 1582
9b371988
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1583.cindex "&'X-Failed-Recipients:'& header line"
1584Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
168e428f
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1585failed addresses, for the benefit of programs that try to analyse such messages
1586automatically.
1587
9b371988 1588.cindex "bounce message" "recipient of"
168e428f
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1589A bounce message is normally sent to the sender of the original message, as
1590obtained from the message's envelope. For incoming SMTP messages, this is the
9b371988
PH
1591address given in the MAIL command. However, when an address is expanded via a
1592forward or alias file, an alternative address can be specified for delivery
1593failures of the generated addresses. For a mailing list expansion (see section
1594&<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1595of the list.
168e428f
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1596
1597
1598
f89d2485 1599.section "Failures to deliver bounce messages" "SECID22"
9b371988 1600.cindex "bounce message" "failure to deliver"
168e428f
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1601If a bounce message (either locally generated or received from a remote host)
1602itself suffers a permanent delivery failure, the message is left on the queue,
1603but it is frozen, awaiting the attention of an administrator. There are options
068aaea8 1604that can be used to make Exim discard such failed messages, or to keep them
9b371988
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1605for only a short time (see &%timeout_frozen_after%& and
1606&%ignore_bounce_errors_after%&).
168e428f
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1607
1608
1609
1610
1611
9b371988
PH
1612. ////////////////////////////////////////////////////////////////////////////
1613. ////////////////////////////////////////////////////////////////////////////
168e428f 1614
f89d2485 1615.chapter "Building and installing Exim" "CHID3"
4f578862 1616.scindex IIDbuex "building Exim"
168e428f 1617
f89d2485
PH
1618.section "Unpacking" "SECID23"
1619Exim is distributed as a gzipped or bzipped tar file which, when unpacked,
168e428f 1620creates a directory with the name of the current release (for example,
9b371988
PH
1621&_exim-&version;_&) into which the following files are placed:
1622
1623.table2 140pt
f89d2485
PH
1624.irow &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1625.irow &_CHANGES_& "contains a reference to where changes are &&&
1626 documented"
1627.irow &_LICENCE_& "the GNU General Public Licence"
1628.irow &_Makefile_& "top-level make file"
1629.irow &_NOTICE_& "conditions for the use of Exim"
1630.irow &_README_& "list of files, directories and simple build &&&
1631 instructions"
9b371988
PH
1632.endtable
1633
1634Other files whose names begin with &_README_& may also be present. The
168e428f
PH
1635following subdirectories are created:
1636
9b371988 1637.table2 140pt
f89d2485
PH
1638.irow &_Local_& "an empty directory for local configuration files"
1639.irow &_OS_& "OS-specific files"
1640.irow &_doc_& "documentation files"
1641.irow &_exim_monitor_& "source files for the Exim monitor"
1642.irow &_scripts_& "scripts used in the build process"
1643.irow &_src_& "remaining source files"
1644.irow &_util_& "independent utilities"
9b371988
PH
1645.endtable
1646
1647The main utility programs are contained in the &_src_& directory, and are built
1648with the Exim binary. The &_util_& directory contains a few optional scripts
168e428f
PH
1649that may be useful to some sites.
1650
1651
f89d2485 1652.section "Multiple machine architectures and operating systems" "SECID24"
9b371988 1653.cindex "building Exim" "multiple OS/architectures"
168e428f
PH
1654The building process for Exim is arranged to make it easy to build binaries for
1655a number of different architectures and operating systems from the same set of
9b371988
PH
1656source files. Compilation does not take place in the &_src_& directory.
1657Instead, a &'build directory'& is created for each architecture and operating
1658system.
1659.cindex "symbolic link" "to build directory"
168e428f 1660Symbolic links to the sources are installed in this directory, which is where
9b371988
PH
1661the actual building takes place. In most cases, Exim can discover the machine
1662architecture and operating system for itself, but the defaults can be
1663overridden if necessary.
168e428f 1664
168e428f 1665
8473d4ee 1666.section "PCRE library" "SECTpcre"
210f147e
NM
1667.cindex "PCRE library"
1668Exim no longer has an embedded PCRE library as the vast majority of
1669modern systems include PCRE as a system library, although you may need
1670to install the PCRE or PCRE development package for your operating
1671system. If your system has a normal PCRE installation the Exim build
1672process will need no further configuration. If the library or the
6a6084f8
PP
1673headers are in an unusual location you will need to either set the PCRE_LIBS
1674and INCLUDE directives appropriately,
1675or set PCRE_CONFIG=yes to use the installed &(pcre-config)& command.
1676If your operating system has no
210f147e
NM
1677PCRE support then you will need to obtain and build the current PCRE
1678from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/).
6a6084f8 1679More information on PCRE is available at &url(http://www.pcre.org/).
210f147e 1680
9b371988
PH
1681.section "DBM libraries" "SECTdb"
1682.cindex "DBM libraries" "discussion of"
1683.cindex "hints database" "DBM files used for"
168e428f
PH
1684Even if you do not use any DBM files in your configuration, Exim still needs a
1685DBM library in order to operate, because it uses indexed files for its hints
1686databases. Unfortunately, there are a number of DBM libraries in existence, and
1687different operating systems often have different ones installed.
1688
9b371988 1689.cindex "Solaris" "DBM library for"
f89d2485
PH
1690.cindex "IRIX, DBM library for"
1691.cindex "BSD, DBM library for"
1692.cindex "Linux, DBM library for"
168e428f
PH
1693If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1694Linux distribution, the DBM configuration should happen automatically, and you
1695may be able to ignore this section. Otherwise, you may have to learn more than
1696you would like about DBM libraries from what follows.
1697
9b371988 1698.cindex "&'ndbm'& DBM library"
168e428f 1699Licensed versions of Unix normally contain a library of DBM functions operating
9b371988 1700via the &'ndbm'& interface, and this is what Exim expects by default. Free
168e428f
PH
1701versions of Unix seem to vary in what they contain as standard. In particular,
1702some early versions of Linux have no default DBM library, and different
1703distributors have chosen to bundle different libraries with their packaged
f89d2485 1704versions. However, the more recent releases seem to have standardized on the
168e428f
PH
1705Berkeley DB library.
1706
1707Different DBM libraries have different conventions for naming the files they
9b371988 1708use. When a program opens a file called &_dbmfile_&, there are several
168e428f
PH
1709possibilities:
1710
9b371988
PH
1711.olist
1712A traditional &'ndbm'& implementation, such as that supplied as part of
1713Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1714.next
1715.cindex "&'gdbm'& DBM library"
1716The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
168e428f 1717compatibility interface it makes two different hard links to it with names
9b371988 1718&_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
168e428f 1719file name is used unmodified.
9b371988
PH
1720.next
1721.cindex "Berkeley DB library"
1722The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1723operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1724programmer exactly the same as the traditional &'ndbm'& implementation.
1725.next
1726If the Berkeley package is used in its native mode, it operates on a single
1727file called &_dbmfile_&; the programmer's interface is somewhat different to
1728the traditional &'ndbm'& interface.
1729.next
1730To complicate things further, there are several very different versions of the
168e428f 1731Berkeley DB package. Version 1.85 was stable for a very long time, releases
9b371988
PH
17322.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1733numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
168e428f 1734versions of Berkeley DB can be obtained from
9b371988
PH
1735&url(http://www.sleepycat.com/).
1736.next
1737.cindex "&'tdb'& DBM library"
1738Yet another DBM library, called &'tdb'&, is available from
1739&url(http://download.sourceforge.net/tdb). It has its own interface, and also
1740operates on a single file.
1741.endlist
1742
1743.cindex "USE_DB"
1744.cindex "DBM libraries" "configuration for building"
168e428f
PH
1745Exim and its utilities can be compiled to use any of these interfaces. In order
1746to use any version of the Berkeley DB package in native mode, you must set
1747USE_DB in an appropriate configuration file (typically
9b371988
PH
1748&_Local/Makefile_&). For example:
1749.code
1750USE_DB=yes
1751.endd
168e428f
PH
1752Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1753error is diagnosed if you set more than one of these.
1754
1755At the lowest level, the build-time configuration sets none of these options,
1756thereby assuming an interface of type (1). However, some operating system
1757configuration files (for example, those for the BSD operating systems and
1758Linux) assume type (4) by setting USE_DB as their default, and the
1759configuration files for Cygwin set USE_GDBM. Anything you set in
9b371988 1760&_Local/Makefile_&, however, overrides these system defaults.
168e428f
PH
1761
1762As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1763necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1764in one of these lines:
9b371988
PH
1765.code
1766DBMLIB = -ldb
1767DBMLIB = -ltdb
1768.endd
168e428f
PH
1769Settings like that will work if the DBM library is installed in the standard
1770place. Sometimes it is not, and the library's header file may also not be in
1771the default path. You may need to set INCLUDE to specify where the header
1772file is, and to specify the path to the library more fully in DBMLIB, as in
1773this example:
9b371988
PH
1774.code
1775INCLUDE=-I/usr/local/include/db-4.1
1776DBMLIB=/usr/local/lib/db-4.1/libdb.a
1777.endd
168e428f 1778There is further detailed discussion about the various DBM libraries in the
9b371988 1779file &_doc/dbm.discuss.txt_& in the Exim distribution.
168e428f
PH
1780
1781
1782
f89d2485 1783.section "Pre-building configuration" "SECID25"
9b371988
PH
1784.cindex "building Exim" "pre-building configuration"
1785.cindex "configuration for building Exim"
1786.cindex "&_Local/Makefile_&"
1787.cindex "&_src/EDITME_&"
168e428f
PH
1788Before building Exim, a local configuration file that specifies options
1789independent of any operating system has to be created with the name
9b371988
PH
1790&_Local/Makefile_&. A template for this file is supplied as the file
1791&_src/EDITME_&, and it contains full descriptions of all the option settings
168e428f
PH
1792therein. These descriptions are therefore not repeated here. If you are
1793building Exim for the first time, the simplest thing to do is to copy
9b371988 1794&_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
168e428f
PH
1795
1796There are three settings that you must supply, because Exim will not build
1797without them. They are the location of the run time configuration file
1798(CONFIGURE_FILE), the directory in which Exim binaries will be installed
1799(BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1800maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1801a colon-separated list of file names; Exim uses the first of them that exists.
1802
1803There are a few other parameters that can be specified either at build time or
1804at run time, to enable the same binary to be used on a number of different
1805machines. However, if the locations of Exim's spool directory and log file
1806directory (if not within the spool directory) are fixed, it is recommended that
9b371988 1807you specify them in &_Local/Makefile_& instead of at run time, so that errors
168e428f
PH
1808detected early in Exim's execution (such as a malformed configuration file) can
1809be logged.
1810
9b371988 1811.cindex "content scanning" "specifying at build time"
068aaea8 1812Exim's interfaces for calling virus and spam scanning software directly from
168e428f
PH
1813access control lists are not compiled by default. If you want to include these
1814facilities, you need to set
9b371988
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1815.code
1816WITH_CONTENT_SCAN=yes
1817.endd
1818in your &_Local/Makefile_&. For details of the facilities themselves, see
1819chapter &<<CHAPexiscan>>&.
168e428f
PH
1820
1821
9b371988 1822.cindex "&_Local/eximon.conf_&"
3cb1b51e 1823.cindex "&_exim_monitor/EDITME_&"
168e428f 1824If you are going to build the Exim monitor, a similar configuration process is
9b371988
PH
1825required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1826your installation and saved under the name &_Local/eximon.conf_&. If you are
1827happy with the default settings described in &_exim_monitor/EDITME_&,
1828&_Local/eximon.conf_& can be empty, but it must exist.
168e428f
PH
1829
1830This is all the configuration that is needed in straightforward cases for known
1831operating systems. However, the building process is set up so that it is easy
1832to override options that are set by default or by operating-system-specific
1833configuration files, for example to change the name of the C compiler, which
9b371988
PH
1834defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1835do this.
168e428f
PH
1836
1837
1838
f89d2485 1839.section "Support for iconv()" "SECID26"
9b371988
PH
1840.cindex "&[iconv()]& support"
1841.cindex "RFC 2047"
168e428f
PH
1842The contents of header lines in messages may be encoded according to the rules
1843described RFC 2047. This makes it possible to transmit characters that are not
1844in the ASCII character set, and to label them as being in a particular
9b371988 1845character set. When Exim is inspecting header lines by means of the &%$h_%&
168e428f
PH
1846mechanism, it decodes them, and translates them into a specified character set
1847(default ISO-8859-1). The translation is possible only if the operating system
9b371988
PH
1848supports the &[iconv()]& function.
1849
1850However, some of the operating systems that supply &[iconv()]& do not support
1851very many conversions. The GNU &%libiconv%& library (available from
1852&url(http://www.gnu.org/software/libiconv/)) can be installed on such
1853systems to remedy this deficiency, as well as on systems that do not supply
1854&[iconv()]& at all. After installing &%libiconv%&, you should add
1855.code
1856HAVE_ICONV=yes
1857.endd
1858to your &_Local/Makefile_& and rebuild Exim.
1859
1860
1861
1862.section "Including TLS/SSL encryption support" "SECTinctlsssl"
1863.cindex "TLS" "including support for TLS"
1864.cindex "encryption" "including support for"
1865.cindex "SUPPORT_TLS"
1866.cindex "OpenSSL" "building Exim with"
1867.cindex "GnuTLS" "building Exim with"
168e428f
PH
1868Exim can be built to support encrypted SMTP connections, using the STARTTLS
1869command as per RFC 2487. It can also support legacy clients that expect to
1870start a TLS session immediately on connection to a non-standard port (see the
9b371988 1871&%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
168e428f
PH
1872line option).
1873
1874If you want to build Exim with TLS support, you must first install either the
1875OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1876implementing SSL.
1877
1878If OpenSSL is installed, you should set
9b371988
PH
1879.code
1880SUPPORT_TLS=yes
1881TLS_LIBS=-lssl -lcrypto
1882.endd
1883in &_Local/Makefile_&. You may also need to specify the locations of the
168e428f 1884OpenSSL library and include files. For example:
9b371988
PH
1885.code
1886SUPPORT_TLS=yes
1887TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1888TLS_INCLUDE=-I/usr/local/openssl/include/
1889.endd
7e6a8985
PP
1890.cindex "pkg-config" "OpenSSL"
1891If you have &'pkg-config'& available, then instead you can just use:
1892.code
1893SUPPORT_TLS=yes
1894USE_OPENSSL_PC=openssl
1895.endd
9b371988 1896.cindex "USE_GNUTLS"
168e428f 1897If GnuTLS is installed, you should set
9b371988
PH
1898.code
1899SUPPORT_TLS=yes
1900USE_GNUTLS=yes
1901TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1902.endd
1903in &_Local/Makefile_&, and again you may need to specify the locations of the
168e428f 1904library and include files. For example:
9b371988
PH
1905.code
1906SUPPORT_TLS=yes
1907USE_GNUTLS=yes
1908TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1909TLS_INCLUDE=-I/usr/gnu/include
1910.endd
7e6a8985
PP
1911.cindex "pkg-config" "GnuTLS"
1912If you have &'pkg-config'& available, then instead you can just use:
1913.code
1914SUPPORT_TLS=yes
1915USE_GNUTLS=yes
1916USE_GNUTLS_PC=gnutls
1917.endd
7e6a8985 1918
168e428f 1919You do not need to set TLS_INCLUDE if the relevant directory is already
9b371988
PH
1920specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1921given in chapter &<<CHAPTLS>>&.
168e428f
PH
1922
1923
1924
1925
b52ed2b3
NM
1926.section "Use of tcpwrappers" "SECID27"
1927
f89d2485 1928.cindex "tcpwrappers, building Exim to support"
9b371988 1929.cindex "USE_TCP_WRAPPERS"
5dc43717
JJ
1930.cindex "TCP_WRAPPERS_DAEMON_NAME"
1931.cindex "tcp_wrappers_daemon_name"
9b371988
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1932Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1933SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
168e428f 1934alternative to Exim's own checking facilities for installations that are
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1935already making use of &'tcpwrappers'& for other purposes. To do this, you
1936should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1937&_tcpd.h_& to be available at compile time, and also ensure that the library
1938&_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1939EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1940you might have
1941.code
1942USE_TCP_WRAPPERS=yes
1943CFLAGS=-O -I/usr/local/include
1944EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1945.endd
5dc43717
JJ
1946in &_Local/Makefile_&. The daemon name to use in the &'tcpwrappers'& control
1947files is &"exim"&. For example, the line
9b371988
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1948.code
1949exim : LOCAL 192.168.1. .friendly.domain.example
1950.endd
1951in your &_/etc/hosts.allow_& file allows connections from the local host, from
1952the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&.
5dc43717
JJ
1953All other connections are denied. The daemon name used by &'tcpwrappers'&
1954can be changed at build time by setting TCP_WRAPPERS_DAEMON_NAME in
a543079f 1955&_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the
5dc43717 1956configure file. Consult the &'tcpwrappers'& documentation for
168e428f 1957further details.
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1958
1959
f89d2485 1960.section "Including support for IPv6" "SECID28"
9b371988 1961.cindex "IPv6" "including support for"
168e428f 1962Exim contains code for use on systems that have IPv6 support. Setting
9b371988 1963&`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
168e428f
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1964it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1965where the IPv6 support is not fully integrated into the normal include and
1966library files.
1967
1968Two different types of DNS record for handling IPv6 addresses have been
f89d2485 1969defined. AAAA records (analogous to A records for IPv4) are in use, and are
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1970currently seen as the mainstream. Another record type called A6 was proposed
1971as better than AAAA because it had more flexibility. However, it was felt to be
9b371988 1972over-complex, and its status was reduced to &"experimental"&. It is not known
168e428f 1973if anyone is actually using A6 records. Exim has support for A6 records, but
9b371988 1974this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
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1975support has not been tested for some time.
1976
1977
1978
0a349494
PP
1979.section "Dynamically loaded lookup module support" "SECTdynamicmodules"
1980.cindex "lookup modules"
1981.cindex "dynamic modules"
1982.cindex ".so building"
1983On some platforms, Exim supports not compiling all lookup types directly into
1984the main binary, instead putting some into external modules which can be loaded
1985on demand.
1986This permits packagers to build Exim with support for lookups with extensive
1987library dependencies without requiring all users to install all of those
1988dependencies.
1989Most, but not all, lookup types can be built this way.
1990
1991Set &`LOOKUP_MODULE_DIR`& to the directory into which the modules will be
1992installed; Exim will only load modules from that directory, as a security
1993measure. You will need to set &`CFLAGS_DYNAMIC`& if not already defined
1994for your OS; see &_OS/Makefile-Linux_& for an example.
1995Some other requirements for adjusting &`EXTRALIBS`& may also be necessary,
1996see &_src/EDITME_& for details.
1997
1998Then, for each module to be loaded dynamically, define the relevant
1999&`LOOKUP_`&<&'lookup_type'&> flags to have the value "2" instead of "yes".
2000For example, this will build in lsearch but load sqlite and mysql support
2001on demand:
2002.code
2003LOOKUP_LSEARCH=yes
2004LOOKUP_SQLITE=2
2005LOOKUP_MYSQL=2
2006.endd
5d758a46 2007
0a349494 2008
f89d2485 2009.section "The building process" "SECID29"
9b371988
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2010.cindex "build directory"
2011Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
2012created, run &'make'& at the top level. It determines the architecture and
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2013operating system types, and creates a build directory if one does not exist.
2014For example, on a Sun system running Solaris 8, the directory
9b371988
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2015&_build-SunOS5-5.8-sparc_& is created.
2016.cindex "symbolic link" "to source files"
168e428f
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2017Symbolic links to relevant source files are installed in the build directory.
2018
9b371988 2019&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
168e428f
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2020building process fails if it is set.
2021
9b371988 2022If this is the first time &'make'& has been run, it calls a script that builds
168e428f 2023a make file inside the build directory, using the configuration files from the
9b371988
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2024&_Local_& directory. The new make file is then passed to another instance of
2025&'make'&. This does the real work, building a number of utility scripts, and
168e428f 2026then compiling and linking the binaries for the Exim monitor (if configured), a
9b371988
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2027number of utility programs, and finally Exim itself. The command &`make
2028makefile`& can be used to force a rebuild of the make file in the build
168e428f
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2029directory, should this ever be necessary.
2030
2031If you have problems building Exim, check for any comments there may be in the
9b371988 2032&_README_& file concerning your operating system, and also take a look at the
168e428f
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2033FAQ, where some common problems are covered.
2034
2035
2036
f89d2485 2037.section 'Output from &"make"&' "SECID283"
9b371988 2038The output produced by the &'make'& process for compile lines is often very
068aaea8
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2039unreadable, because these lines can be very long. For this reason, the normal
2040output is suppressed by default, and instead output similar to that which
2041appears when compiling the 2.6 Linux kernel is generated: just a short line for
2042each module that is being compiled or linked. However, it is still possible to
9b371988
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2043get the full output, by calling &'make'& like this:
2044.code
2045FULLECHO='' make -e
2046.endd
2047The value of FULLECHO defaults to &"@"&, the flag character that suppresses
2048command reflection in &'make'&. When you ask for the full output, it is
3cb1b51e 2049given in addition to the short output.
068aaea8
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2050
2051
2052
9b371988 2053.section "Overriding build-time options for Exim" "SECToverride"
f89d2485 2054.cindex "build-time options, overriding"
168e428f
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2055The main make file that is created at the beginning of the building process
2056consists of the concatenation of a number of files which set configuration
9b371988 2057values, followed by a fixed set of &'make'& instructions. If a value is set
168e428f
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2058more than once, the last setting overrides any previous ones. This provides a
2059convenient way of overriding defaults. The files that are concatenated are, in
2060order:
9b371988
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2061.display
2062&_OS/Makefile-Default_&
2063&_OS/Makefile-_&<&'ostype'&>
2064&_Local/Makefile_&
2065&_Local/Makefile-_&<&'ostype'&>
2066&_Local/Makefile-_&<&'archtype'&>
2067&_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
2068&_OS/Makefile-Base_&
2069.endd
2070.cindex "&_Local/Makefile_&"
2071.cindex "building Exim" "operating system type"
2072.cindex "building Exim" "architecture type"
2073where <&'ostype'&> is the operating system type and <&'archtype'&> is the
2074architecture type. &_Local/Makefile_& is required to exist, and the building
2075process fails if it is absent. The other three &_Local_& files are optional,
168e428f
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2076and are often not needed.
2077
9b371988
PH
2078The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
2079called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
168e428f
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2080the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
2081values are used, thereby providing a means of forcing particular settings.
9b371988 2082Otherwise, the scripts try to get values from the &%uname%& command. If this
168e428f 2083fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
9b371988 2084of &'ad hoc'& transformations are then applied, to produce the standard names
168e428f
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2085that Exim expects. You can run these scripts directly from the shell in order
2086to find out what values are being used on your system.
2087
2088
9b371988 2089&_OS/Makefile-Default_& contains comments about the variables that are set
168e428f
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2090therein. Some (but not all) are mentioned below. If there is something that
2091needs changing, review the contents of this file and the contents of the make
9b371988 2092file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
168e428f
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2093default values are.
2094
2095
9b371988
PH
2096.cindex "building Exim" "overriding default settings"
2097If you need to change any of the values that are set in &_OS/Makefile-Default_&
2098or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
168e428f 2099need to change the original files. Instead, you should make the changes by
9b371988
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2100putting the new values in an appropriate &_Local_& file. For example,
2101.cindex "Tru64-Unix build-time settings"
168e428f
PH
2102when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2103formerly DEC-OSF1) operating system, it is necessary to specify that the C
9b371988
PH
2104compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2105called with the option &%-std1%&, to make it recognize some of the features of
168e428f 2106Standard C that Exim uses. (Most other compilers recognize Standard C by
9b371988 2107default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
168e428f 2108containing the lines
9b371988
PH
2109.code
2110CC=cc
2111CFLAGS=-std1
2112.endd
168e428f 2113If you are compiling for just one operating system, it may be easier to put
9b371988 2114these lines directly into &_Local/Makefile_&.
168e428f
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2115
2116Keeping all your local configuration settings separate from the distributed
2117files makes it easy to transfer them to new versions of Exim simply by copying
9b371988 2118the contents of the &_Local_& directory.
168e428f
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2119
2120
9b371988
PH
2121.cindex "NIS lookup type" "including support for"
2122.cindex "NIS+ lookup type" "including support for"
2123.cindex "LDAP" "including support for"
2124.cindex "lookup" "inclusion in binary"
168e428f
PH
2125Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2126lookup, but not all systems have these components installed, so the default is
2127not to include the relevant code in the binary. All the different kinds of file
2128and database lookup that Exim supports are implemented as separate code modules
2129which are included only if the relevant compile-time options are set. In the
9b371988
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2130case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2131.code
2132LOOKUP_LDAP=yes
2133LOOKUP_NIS=yes
2134LOOKUP_NISPLUS=yes
2135.endd
168e428f 2136and similar settings apply to the other lookup types. They are all listed in
9b371988 2137&_src/EDITME_&. In many cases the relevant include files and interface
168e428f 2138libraries need to be installed before compiling Exim.
9b371988 2139.cindex "cdb" "including support for"
068aaea8
PH
2140However, there are some optional lookup types (such as cdb) for which
2141the code is entirely contained within Exim, and no external include
168e428f
PH
2142files or libraries are required. When a lookup type is not included in the
2143binary, attempts to configure Exim to use it cause run time configuration
2144errors.
2145
7e6a8985
PP
2146.cindex "pkg-config" "lookups"
2147.cindex "pkg-config" "authenticators"
252e0c7b
PP
2148Many systems now use a tool called &'pkg-config'& to encapsulate information
2149about how to compile against a library; Exim has some initial support for
2150being able to use pkg-config for lookups and authenticators. For any given
2151makefile variable which starts &`LOOKUP_`& or &`AUTH_`&, you can add a new
2152variable with the &`_PC`& suffix in the name and assign as the value the
2153name of the package to be queried. The results of querying via the
2154&'pkg-config'& command will be added to the appropriate Makefile variables
2155with &`+=`& directives, so your version of &'make'& will need to support that
2156syntax. For instance:
2157.code
2158LOOKUP_SQLITE=yes
2159LOOKUP_SQLITE_PC=sqlite3
2160AUTH_GSASL=yes
2161AUTH_GSASL_PC=libgsasl
2162AUTH_HEIMDAL_GSSAPI=yes
2163AUTH_HEIMDAL_GSSAPI_PC=heimdal-gssapi
2164.endd
252e0c7b 2165
9b371988 2166.cindex "Perl" "including support for"
168e428f
PH
2167Exim can be linked with an embedded Perl interpreter, allowing Perl
2168subroutines to be called during string expansion. To enable this facility,
9b371988
PH
2169.code
2170EXIM_PERL=perl.o
2171.endd
2172must be defined in &_Local/Makefile_&. Details of this facility are given in
2173chapter &<<CHAPperl>>&.
168e428f 2174
f89d2485 2175.cindex "X11 libraries, location of"
168e428f 2176The location of the X11 libraries is something that varies a lot between
068aaea8 2177operating systems, and there may be different versions of X11 to cope
168e428f
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2178with. Exim itself makes no use of X11, but if you are compiling the Exim
2179monitor, the X11 libraries must be available.
9b371988
PH
2180The following three variables are set in &_OS/Makefile-Default_&:
2181.code
2182X11=/usr/X11R6
2183XINCLUDE=-I$(X11)/include
2184XLFLAGS=-L$(X11)/lib
2185.endd
168e428f 2186These are overridden in some of the operating-system configuration files. For
9b371988
PH
2187example, in &_OS/Makefile-SunOS5_& there is
2188.code
2189X11=/usr/openwin
2190XINCLUDE=-I$(X11)/include
2191XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2192.endd
168e428f
PH
2193If you need to override the default setting for your operating system, place a
2194definition of all three of these variables into your
9b371988 2195&_Local/Makefile-<ostype>_& file.
168e428f 2196
9b371988 2197.cindex "EXTRALIBS"
168e428f
PH
2198If you need to add any extra libraries to the link steps, these can be put in a
2199variable called EXTRALIBS, which appears in all the link commands, but by
2200default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2201command for linking the main Exim binary, and not for any associated utilities.
2202
9b371988 2203.cindex "DBM libraries" "configuration for building"
168e428f 2204There is also DBMLIB, which appears in the link commands for binaries that
9b371988 2205use DBM functions (see also section &<<SECTdb>>&). Finally, there is
168e428f
PH
2206EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2207binary, and which can be used, for example, to include additional X11
2208libraries.
2209
9b371988 2210.cindex "configuration file" "editing"
168e428f
PH
2211The make file copes with rebuilding Exim correctly if any of the configuration
2212files are edited. However, if an optional configuration file is deleted, it is
9b371988
PH
2213necessary to touch the associated non-optional file (that is,
2214&_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
168e428f
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2215
2216
f89d2485 2217.section "OS-specific header files" "SECID30"
9b371988
PH
2218.cindex "&_os.h_&"
2219.cindex "building Exim" "OS-specific C header files"
2220The &_OS_& directory contains a number of files with names of the form
2221&_os.h-<ostype>_&. These are system-specific C header files that should not
168e428f 2222normally need to be changed. There is a list of macro settings that are
9b371988 2223recognized in the file &_OS/os.configuring_&, which should be consulted if you
168e428f
PH
2224are porting Exim to a new operating system.
2225
2226
2227
f89d2485
PH
2228.section "Overriding build-time options for the monitor" "SECID31"
2229.cindex "building Eximon"
168e428f
PH
2230A similar process is used for overriding things when building the Exim monitor,
2231where the files that are involved are
9b371988
PH
2232.display
2233&_OS/eximon.conf-Default_&
2234&_OS/eximon.conf-_&<&'ostype'&>
2235&_Local/eximon.conf_&
2236&_Local/eximon.conf-_&<&'ostype'&>
2237&_Local/eximon.conf-_&<&'archtype'&>
2238&_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2239.endd
2240.cindex "&_Local/eximon.conf_&"
168e428f 2241As with Exim itself, the final three files need not exist, and in this case the
9b371988
PH
2242&_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2243&_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
168e428f
PH
2244variables of the same name, preceded by EXIMON_. For example, setting
2245EXIMON_LOG_DEPTH in the environment overrides the value of
2246LOG_DEPTH at run time.
4f578862 2247.ecindex IIDbuex
168e428f
PH
2248
2249
f89d2485 2250.section "Installing Exim binaries and scripts" "SECID32"
9b371988
PH
2251.cindex "installing Exim"
2252.cindex "BIN_DIRECTORY"
2253The command &`make install`& runs the &(exim_install)& script with no
2254arguments. The script copies binaries and utility scripts into the directory
2255whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2256.cindex "setuid" "installing Exim with"
068aaea8
PH
2257The install script copies files only if they are newer than the files they are
2258going to replace. The Exim binary is required to be owned by root and have the
9b371988
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2259&'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2260install`& as root so that it can set up the Exim binary in this way. However, in
068aaea8
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2261some special situations (for example, if a host is doing no local deliveries)
2262it may be possible to run Exim without making the binary setuid root (see
9b371988 2263chapter &<<CHAPsecurity>>& for details).
168e428f 2264
9b371988 2265.cindex "CONFIGURE_FILE"
168e428f 2266Exim's run time configuration file is named by the CONFIGURE_FILE setting
9b371988
PH
2267in &_Local/Makefile_&. If this names a single file, and the file does not
2268exist, the default configuration file &_src/configure.default_& is copied there
168e428f
PH
2269by the installation script. If a run time configuration file already exists, it
2270is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2271alternative files, no default is installed.
2272
9b371988
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2273.cindex "system aliases file"
2274.cindex "&_/etc/aliases_&"
168e428f
PH
2275One change is made to the default configuration file when it is installed: the
2276default configuration contains a router that references a system aliases file.
2277The path to this file is set to the value specified by
9b371988 2278SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
168e428f
PH
2279If the system aliases file does not exist, the installation script creates it,
2280and outputs a comment to the user.
2281
2282The created file contains no aliases, but it does contain comments about the
2283aliases a site should normally have. Mail aliases have traditionally been
9b371988
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2284kept in &_/etc/aliases_&. However, some operating systems are now using
2285&_/etc/mail/aliases_&. You should check if yours is one of these, and change
168e428f
PH
2286Exim's configuration if necessary.
2287
2288The default configuration uses the local host's name as the only local domain,
9b371988
PH
2289and is set up to do local deliveries into the shared directory &_/var/mail_&,
2290running as the local user. System aliases and &_.forward_& files in users' home
168e428f
PH
2291directories are supported, but no NIS or NIS+ support is configured. Domains
2292other than the name of the local host are routed using the DNS, with delivery
2293over SMTP.
2294
168e428f
PH
2295It is possible to install Exim for special purposes (such as building a binary
2296distribution) in a private part of the file system. You can do this by a
2297command such as
9b371988
PH
2298.code
2299make DESTDIR=/some/directory/ install
2300.endd
168e428f
PH
2301This has the effect of pre-pending the specified directory to all the file
2302paths, except the name of the system aliases file that appears in the default
9b371988 2303configuration. (If a default alias file is created, its name &'is'& modified.)
168e428f
PH
2304For backwards compatibility, ROOT is used if DESTDIR is not set,
2305but this usage is deprecated.
2306
9b371988
PH
2307.cindex "installing Exim" "what is not installed"
2308Running &'make install'& does not copy the Exim 4 conversion script
40df1be3
TF
2309&'convert4r4'&. You will probably run this only once if you are
2310upgrading from Exim 3. None of the documentation files in the &_doc_&
168e428f 2311directory are copied, except for the info files when you have set
9b371988 2312INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
168e428f 2313
9b371988 2314For the utility programs, old versions are renamed by adding the suffix &_.O_&
168e428f
PH
2315to their names. The Exim binary itself, however, is handled differently. It is
2316installed under a name that includes the version number and the compile number,
9b371988
PH
2317for example &_exim-&version;-1_&. The script then arranges for a symbolic link
2318called &_exim_& to point to the binary. If you are updating a previous version
2319of Exim, the script takes care to ensure that the name &_exim_& is never absent
168e428f
PH
2320from the directory (as seen by other processes).
2321
9b371988
PH
2322.cindex "installing Exim" "testing the script"
2323If you want to see what the &'make install'& will do before running it for
2324real, you can pass the &%-n%& option to the installation script by this
2325command:
2326.code
2327make INSTALL_ARG=-n install
2328.endd
168e428f
PH
2329The contents of the variable INSTALL_ARG are passed to the installation
2330script. You do not need to be root to run this test. Alternatively, you can run
2331the installation script directly, but this must be from within the build
2332directory. For example, from the top-level Exim directory you could use this
2333command:
9b371988
PH
2334.code
2335(cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2336.endd
2337.cindex "installing Exim" "install script options"
168e428f
PH
2338There are two other options that can be supplied to the installation script.
2339
9b371988
PH
2340.ilist
2341&%-no_chown%& bypasses the call to change the owner of the installed binary
168e428f 2342to root, and the call to make it a setuid binary.
9b371988
PH
2343.next
2344&%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
168e428f 2345installed binary.
9b371988 2346.endlist
168e428f
PH
2347
2348INSTALL_ARG can be used to pass these options to the script. For example:
9b371988
PH
2349.code
2350make INSTALL_ARG=-no_symlink install
2351.endd
168e428f
PH
2352The installation script can also be given arguments specifying which files are
2353to be copied. For example, to install just the Exim binary, and nothing else,
2354without creating the symbolic link, you could use:
9b371988
PH
2355.code
2356make INSTALL_ARG='-no_symlink exim' install
2357.endd
168e428f
PH
2358
2359
2360
9b371988
PH
2361.section "Installing info documentation" "SECTinsinfdoc"
2362.cindex "installing Exim" "&'info'& documentation"
2363Not all systems use the GNU &'info'& system for documentation, and for this
168e428f
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2364reason, the Texinfo source of Exim's documentation is not included in the main
2365distribution. Instead it is available separately from the ftp site (see section
9b371988 2366&<<SECTavail>>&).
168e428f 2367
9b371988
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2368If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2369source of the documentation is found in the source tree, running &`make
2370install`& automatically builds the info files and installs them.
168e428f
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2371
2372
2373
f89d2485 2374.section "Setting up the spool directory" "SECID33"
9b371988 2375.cindex "spool directory" "creating"
168e428f
PH
2376When it starts up, Exim tries to create its spool directory if it does not
2377exist. The Exim uid and gid are used for the owner and group of the spool
2378directory. Sub-directories are automatically created in the spool directory as
2379necessary.
2380
2381
2382
2383
f89d2485 2384.section "Testing" "SECID34"
9b371988 2385.cindex "testing" "installation"
168e428f
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2386Having installed Exim, you can check that the run time configuration file is
2387syntactically valid by running the following command, which assumes that the
2388Exim binary directory is within your PATH environment variable:
9b371988
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2389.code
2390exim -bV
2391.endd
168e428f
PH
2392If there are any errors in the configuration file, Exim outputs error messages.
2393Otherwise it outputs the version number and build date,
2394the DBM library that is being used, and information about which drivers and
2395other optional code modules are included in the binary.
2396Some simple routing tests can be done by using the address testing option. For
2397example,
9b371988
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2398.display
2399&`exim -bt`& <&'local username'&>
2400.endd
168e428f 2401should verify that it recognizes a local mailbox, and
9b371988
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2402.display
2403&`exim -bt`& <&'remote address'&>
2404.endd
168e428f
PH
2405a remote one. Then try getting it to deliver mail, both locally and remotely.
2406This can be done by passing messages directly to Exim, without going through a
2407user agent. For example:
9b371988 2408.code
068aaea8
PH
2409exim -v postmaster@your.domain.example
2410From: user@your.domain.example
2411To: postmaster@your.domain.example
2412Subject: Testing Exim
168e428f 2413
068aaea8
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2414This is a test message.
2415^D
9b371988
PH
2416.endd
2417The &%-v%& option causes Exim to output some verification of what it is doing.
168e428f 2418In this case you should see copies of three log lines, one for the message's
9b371988 2419arrival, one for its delivery, and one containing &"Completed"&.
168e428f 2420
9b371988
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2421.cindex "delivery" "problems with"
2422If you encounter problems, look at Exim's log files (&'mainlog'& and
2423&'paniclog'&) to see if there is any relevant information there. Another source
168e428f 2424of information is running Exim with debugging turned on, by specifying the
9b371988 2425&%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
168e428f 2426with debugging turned on by a command of the form
9b371988
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2427.display
2428&`exim -d -M`& <&'exim-message-id'&>
2429.endd
2430You must be root or an &"admin user"& in order to do this. The &%-d%& option
168e428f 2431produces rather a lot of output, but you can cut this down to specific areas.
9b371988
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2432For example, if you use &%-d-all+route%& only the debugging information
2433relevant to routing is included. (See the &%-d%& option in chapter
2434&<<CHAPcommandline>>& for more details.)
168e428f 2435
9b371988
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2436.cindex '&"sticky"& bit'
2437.cindex "lock files"
168e428f
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2438One specific problem that has shown up on some sites is the inability to do
2439local deliveries into a shared mailbox directory, because it does not have the
9b371988 2440&"sticky bit"& set on it. By default, Exim tries to create a lock file before
168e428f 2441writing to a mailbox file, and if it cannot create the lock file, the delivery
9b371988 2442is deferred. You can get round this either by setting the &"sticky bit"& on the
168e428f
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2443directory, or by setting a specific group for local deliveries and allowing
2444that group to create files in the directory (see the comments above the
9b371988 2445&(local_delivery)& transport in the default configuration file). Another
168e428f 2446approach is to configure Exim not to use lock files, but just to rely on
9b371988
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2447&[fcntl()]& locking instead. However, you should do this only if all user
2448agents also use &[fcntl()]& locking. For further discussion of locking issues,
2449see chapter &<<CHAPappendfile>>&.
168e428f
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2450
2451One thing that cannot be tested on a system that is already running an MTA is
2452the receipt of incoming SMTP mail on the standard SMTP port. However, the
9b371988
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2453&%-oX%& option can be used to run an Exim daemon that listens on some other
2454port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2455&'exim_checkaccess'& utility can be used to check out policy controls on
168e428f
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2456incoming SMTP mail.
2457
2458Testing a new version on a system that is already running Exim can most easily
2459be done by building a binary with a different CONFIGURE_FILE setting. From
2460within the run time configuration, all other file and directory names
2461that Exim uses can be altered, in order to keep it entirely clear of the
2462production version.
2463
2464
f89d2485 2465.section "Replacing another MTA with Exim" "SECID35"
9b371988 2466.cindex "replacing another MTA"
168e428f
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2467Building and installing Exim for the first time does not of itself put it in
2468general use. The name by which the system's MTA is called by mail user agents
9b371988
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2469is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2470operating system), and it is necessary to make this name point to the &'exim'&
168e428f 2471binary in order to get the user agents to pass messages to Exim. This is
9b371988
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2472normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2473or &_/usr/lib/sendmail_&
2474.cindex "symbolic link" "to &'exim'& binary"
2475a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
168e428f
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2476privilege and executable status from the old MTA. It is then necessary to stop
2477and restart the mailer daemon, if one is running.
2478
f89d2485 2479.cindex "FreeBSD, MTA indirection"
9b371988 2480.cindex "&_/etc/mail/mailer.conf_&"
168e428f
PH
2481Some operating systems have introduced alternative ways of switching MTAs. For
2482example, if you are running FreeBSD, you need to edit the file
9b371988 2483&_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
168e428f
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2484described. A typical example of the contents of this file for running Exim is
2485as follows:
9b371988
PH
2486.code
2487sendmail /usr/exim/bin/exim
2488send-mail /usr/exim/bin/exim
2489mailq /usr/exim/bin/exim -bp
2490newaliases /usr/bin/true
2491.endd
2492Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2493your Exim installation is &"live"&. Check it by sending a message from your
168e428f
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2494favourite user agent.
2495
2496You should consider what to tell your users about the change of MTA. Exim may
2497have different capabilities to what was previously running, and there are
2498various operational differences such as the text of messages produced by
2499command line options and in bounce messages. If you allow your users to make
2500use of Exim's filtering capabilities, you should make the document entitled
9b371988 2501&'Exim's interface to mail filtering'& available to them.
168e428f
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2502
2503
2504
f89d2485 2505.section "Upgrading Exim" "SECID36"
9b371988 2506.cindex "upgrading Exim"
168e428f
PH
2507If you are already running Exim on your host, building and installing a new
2508version automatically makes it available to MUAs, or any other programs that
2509call the MTA directly. However, if you are running an Exim daemon, you do need
9b371988
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2510to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2511new binary. You do not need to stop processing mail in order to install a new
068aaea8
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2512version of Exim. The install script does not modify an existing runtime
2513configuration file.
2514
168e428f
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2515
2516
2517
f89d2485 2518.section "Stopping the Exim daemon on Solaris" "SECID37"
9b371988 2519.cindex "Solaris" "stopping Exim on"
168e428f 2520The standard command for stopping the mailer daemon on Solaris is
9b371988
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2521.code
2522/etc/init.d/sendmail stop
2523.endd
2524If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2525fails to stop Exim because it uses the command &'ps -e'& and greps the output
2526for the text &"sendmail"&; this is not present because the actual program name
2527(that is, &"exim"&) is given by the &'ps'& command with these options. A
2528solution is to replace the line that finds the process id with something like
2529.code
2530pid=`cat /var/spool/exim/exim-daemon.pid`
2531.endd
168e428f
PH
2532to obtain the daemon's pid directly from the file that Exim saves it in.
2533
9b371988 2534Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
168e428f
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2535still be received from local processes, and if automatic delivery is configured
2536(the normal case), deliveries will still occur.
2537
2538
2539
2540
9b371988
PH
2541. ////////////////////////////////////////////////////////////////////////////
2542. ////////////////////////////////////////////////////////////////////////////
168e428f 2543
9b371988 2544.chapter "The Exim command line" "CHAPcommandline"
4f578862
PH
2545.scindex IIDclo1 "command line" "options"
2546.scindex IIDclo2 "options" "command line"
168e428f
PH
2547Exim's command line takes the standard Unix form of a sequence of options,
2548each starting with a hyphen character, followed by a number of arguments. The
2549options are compatible with the main options of Sendmail, and there are also
2550some additional options, some of which are compatible with Smail 3. Certain
2551combinations of options do not make sense, and provoke an error if used.
2552The form of the arguments depends on which options are set.
2553
2554
f89d2485 2555.section "Setting options by program name" "SECID38"
9b371988
PH
2556.cindex "&'mailq'&"
2557If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
168e428f 2558were present before any other options.
9b371988 2559The &%-bp%& option requests a listing of the contents of the mail queue on the
168e428f
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2560standard output.
2561This feature is for compatibility with some systems that contain a command of
2562that name in one of the standard libraries, symbolically linked to
9b371988
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2563&_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2564
2565.cindex "&'rsmtp'&"
2566If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2567were present before any other options, for compatibility with Smail. The
2568&%-bS%& option is used for reading in a number of messages in batched SMTP
2569format.
2570
2571.cindex "&'rmail'&"
2572If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2573&%-oee%& options were present before any other options, for compatibility with
2574Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2575
2576.cindex "&'runq'&"
2577.cindex "queue runner"
2578If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2579were present before any other options, for compatibility with Smail. The &%-q%&
168e428f
PH
2580option causes a single queue runner process to be started.
2581
9b371988
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2582.cindex "&'newaliases'&"
2583.cindex "alias file" "building"
2584.cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2585If Exim is called under the name &'newaliases'& it behaves as if the option
2586&%-bi%& were present before any other options, for compatibility with Sendmail.
168e428f
PH
2587This option is used for rebuilding Sendmail's alias file. Exim does not have
2588the concept of a single alias file, but can be configured to run a given
9b371988 2589command if called with the &%-bi%& option.
168e428f
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2590
2591
9b371988
PH
2592.section "Trusted and admin users" "SECTtrustedadmin"
2593Some Exim options are available only to &'trusted users'& and others are
2594available only to &'admin users'&. In the description below, the phrases &"Exim
2595user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2596EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2597&%exim_group%& options. These do not necessarily have to use the name &"exim"&.
168e428f 2598
9b371988 2599.ilist
f89d2485 2600.cindex "trusted users" "definition of"
9b371988 2601.cindex "user" "trusted definition of"
168e428f 2602The trusted users are root, the Exim user, any user listed in the
9b371988
PH
2603&%trusted_users%& configuration option, and any user whose current group or any
2604supplementary group is one of those listed in the &%trusted_groups%&
168e428f 2605configuration option. Note that the Exim group is not automatically trusted.
9b371988
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2606
2607.cindex '&"From"& line'
2608.cindex "envelope sender"
2609Trusted users are always permitted to use the &%-f%& option or a leading
2610&"From&~"& line to specify the envelope sender of a message that is passed to
2611Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2612See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2613users to set envelope senders.
2614
2615.cindex "&'From:'& header line"
2616.cindex "&'Sender:'& header line"
2617For a trusted user, there is never any check on the contents of the &'From:'&
2618header line, and a &'Sender:'& line is never added. Furthermore, any existing
2619&'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2620
168e428f
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2621Trusted users may also specify a host name, host address, interface address,
2622protocol name, ident value, and authentication data when submitting a message
2623locally. Thus, they are able to insert messages into Exim's queue locally that
2624have the characteristics of messages received from a remote host. Untrusted
9b371988 2625users may in some circumstances use &%-f%&, but can never set the other values
168e428f 2626that are available to trusted users.
9b371988
PH
2627.next
2628.cindex "user" "admin definition of"
2629.cindex "admin user" "definition of"
168e428f 2630The admin users are root, the Exim user, and any user that is a member of the
9b371988 2631Exim group or of any group listed in the &%admin_groups%& configuration option.
168e428f 2632The current group does not have to be one of these groups.
9b371988 2633
168e428f
PH
2634Admin users are permitted to list the queue, and to carry out certain
2635operations on messages, for example, to force delivery failures. It is also
2636necessary to be an admin user in order to see the full information provided by
2637the Exim monitor, and full debugging output.
9b371988
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2638
2639By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2640Exim to attempt delivery of messages on its queue is restricted to admin users.
2641However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2642option false (that is, specifying &%no_prod_requires_admin%&).
2643
2644Similarly, the use of the &%-bp%& option to list all the messages in the queue
2645is restricted to admin users unless &%queue_list_requires_admin%& is set
168e428f 2646false.
9b371988 2647.endlist
168e428f
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2648
2649
9b371988 2650&*Warning*&: If you configure your system so that admin users are able to
168e428f
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2651edit Exim's configuration file, you are giving those users an easy way of
2652getting root. There is further discussion of this issue at the start of chapter
9b371988 2653&<<CHAPconf>>&.
168e428f
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2654
2655
2656
2657
f89d2485 2658.section "Command line options" "SECID39"
db9452a9
PH
2659Exim's command line options are described in alphabetical order below. If none
2660of the options that specifies a specific action (such as starting the daemon or
2661a queue runner, or testing an address, or receiving a message in a specific
2662format, or listing the queue) are present, and there is at least one argument
2663on the command line, &%-bm%& (accept a local message on the standard input,
2664with the arguments specifying the recipients) is assumed. Otherwise, Exim
2665outputs a brief message about itself and exits.
168e428f 2666
9b371988
PH
2667. ////////////////////////////////////////////////////////////////////////////
2668. Insert a stylized XML comment here, to identify the start of the command line
2669. options. This is for the benefit of the Perl script that automatically
2670. creates a man page for the options.
2671. ////////////////////////////////////////////////////////////////////////////
168e428f 2672
9b371988 2673.literal xml
168e428f 2674<!-- === Start of command line options === -->
9b371988 2675.literal off
168e428f
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2676
2677
9b371988
PH
2678.vlist
2679.vitem &%--%&
2680.oindex "--"
2681.cindex "options" "command line; terminating"
168e428f
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2682This is a pseudo-option whose only purpose is to terminate the options and
2683therefore to cause subsequent command line items to be treated as arguments
2684rather than options, even if they begin with hyphens.
2685
9b371988
PH
2686.vitem &%--help%&
2687.oindex "&%--help%&"
168e428f
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2688This option causes Exim to output a few sentences stating what it is.
2689The same output is generated if the Exim binary is called with no options and
2690no arguments.
2691
4b2241d2
PP
2692.vitem &%--version%&
2693.oindex "&%--version%&"
2694This option is an alias for &%-bV%& and causes version information to be
2695displayed.
2696
a3fb9793
PP
2697.new
2698.vitem &%-Ac%& &&&
2699 &%-Am%&
2700.oindex "&%-Ac%&"
2701.oindex "&%-Am%&"
2702These options are used by Sendmail for selecting configuration files and are
2703ignored by Exim.
2704.wen
2705
9b371988
PH
2706.vitem &%-B%&<&'type'&>
2707.oindex "&%-B%&"
2708.cindex "8-bit characters"
2709.cindex "Sendmail compatibility" "8-bit characters"
168e428f
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2710This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2711clean; it ignores this option.
2712
9b371988
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2713.vitem &%-bd%&
2714.oindex "&%-bd%&"
2715.cindex "daemon"
f89d2485 2716.cindex "SMTP" "listener"
9b371988 2717.cindex "queue runner"
168e428f 2718This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
9b371988
PH
2719the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2720that the daemon should also initiate periodic queue runs.
2721
2722The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2723(debugging) or &%-v%& (verifying) options are set, the daemon does not
168e428f
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2724disconnect from the controlling terminal. When running this way, it can be
2725stopped by pressing ctrl-C.
9b371988 2726
168e428f
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2727By default, Exim listens for incoming connections to the standard SMTP port on
2728all the host's running interfaces. However, it is possible to listen on other
2729ports, on multiple ports, and only on specific interfaces. Chapter
9b371988
PH
2730&<<CHAPinterfaces>>& contains a description of the options that control this.
2731
168e428f 2732When a listening daemon
9b371988
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2733.cindex "daemon" "process id (pid)"
2734.cindex "pid (process id)" "of daemon"
2735is started without the use of &%-oX%& (that is, without overriding the normal
2736configuration), it writes its process id to a file called &_exim-daemon.pid_&
2737in Exim's spool directory. This location can be overridden by setting
2738PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
168e428f 2739running as root.
9b371988
PH
2740
2741When &%-oX%& is used on the command line to start a listening daemon, the
2742process id is not written to the normal pid file path. However, &%-oP%& can be
168e428f 2743used to specify a path on the command line if a pid file is required.
9b371988 2744
168e428f 2745The SIGHUP signal
9b371988 2746.cindex "SIGHUP"
3cb1b51e
PH
2747.cindex "daemon" "restarting"
2748can be used to cause the daemon to re-execute itself. This should be done
2749whenever Exim's configuration file, or any file that is incorporated into it by
2750means of the &%.include%& facility, is changed, and also whenever a new version
2751of Exim is installed. It is not necessary to do this when other files that are
9b371988
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2752referenced from the configuration (for example, alias files) are changed,
2753because these are reread each time they are used.
2754
2755.vitem &%-bdf%&
2756.oindex "&%-bdf%&"
2757This option has the same effect as &%-bd%& except that it never disconnects
2758from the controlling terminal, even when no debugging is specified.
2759
2760.vitem &%-be%&
2761.oindex "&%-be%&"
2762.cindex "testing" "string expansion"
2763.cindex "expansion" "testing"
168e428f
PH
2764Run Exim in expansion testing mode. Exim discards its root privilege, to
2765prevent ordinary users from using this mode to read otherwise inaccessible
2766files. If no arguments are given, Exim runs interactively, prompting for lines
4f578862 2767of data. Otherwise, it processes each argument in turn.
9b371988
PH
2768
2769If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2770to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2771used without command line arguments. If successful, it uses the &[readline()]&
168e428f
PH
2772function, which provides extensive line-editing facilities, for reading the
2773test data. A line history is supported.
9b371988 2774
168e428f 2775Long expansion expressions can be split over several lines by using backslash
068aaea8 2776continuations. As in Exim's run time configuration, white space at the start of
168e428f
PH
2777continuation lines is ignored. Each argument or data line is passed through the
2778string expansion mechanism, and the result is output. Variable values from the
9b371988 2779configuration file (for example, &$qualify_domain$&) are available, but no
3cb1b51e 2780message-specific values (such as &$sender_domain$&) are set, because no message
f89d2485 2781is being processed (but see &%-bem%& and &%-Mset%&).
168e428f 2782
9b371988
PH
2783&*Note*&: If you use this mechanism to test lookups, and you change the data
2784files or databases you are using, you must exit and restart Exim before trying
2785the same lookup again. Otherwise, because each Exim process caches the results
2786of lookups, you will just get the same result as before.
9b371988 2787
3cb1b51e
PH
2788.vitem &%-bem%&&~<&'filename'&>
2789.oindex "&%-bem%&"
2790.cindex "testing" "string expansion"
2791.cindex "expansion" "testing"
2792This option operates like &%-be%& except that it must be followed by the name
2793of a file. For example:
2794.code
2795exim -bem /tmp/testmessage
2796.endd
2797The file is read as a message (as if receiving a locally-submitted non-SMTP
2798message) before any of the test expansions are done. Thus, message-specific
2799variables such as &$message_size$& and &$header_from:$& are available. However,
2800no &'Received:'& header is added to the message. If the &%-t%& option is set,
2801recipients are read from the headers in the normal way, and are shown in the
2802&$recipients$& variable. Note that recipients cannot be given on the command
2803line, because further arguments are taken as strings to expand (just like
2804&%-be%&).
3cb1b51e 2805
9b371988
PH
2806.vitem &%-bF%&&~<&'filename'&>
2807.oindex "&%-bF%&"
2808.cindex "system filter" "testing"
2809.cindex "testing" "system filter"
2810This option is the same as &%-bf%& except that it assumes that the filter being
168e428f
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2811tested is a system filter. The additional commands that are available only in
2812system filters are recognized.
2813
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2814.vitem &%-bf%&&~<&'filename'&>
2815.oindex "&%-bf%&"
2816.cindex "filter" "testing"
2817.cindex "testing" "filter file"
2818.cindex "forward file" "testing"
2819.cindex "testing" "forward file"
2820.cindex "Sieve filter" "testing"
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2821This option runs Exim in user filter testing mode; the file is the filter file
2822to be tested, and a test message must be supplied on the standard input. If
2823there are no message-dependent tests in the filter, an empty file can be
2824supplied.
168e428f 2825
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2826If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2827can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2828filter and a user filter in the same run. For example:
2829.code
2830exim -bF /system/filter -bf /user/filter </test/message
2831.endd
168e428f
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2832This is helpful when the system filter adds header lines or sets filter
2833variables that are used by the user filter.
168e428f 2834
9b371988
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2835If the test filter file does not begin with one of the special lines
2836.code
2837# Exim filter
2838# Sieve filter
2839.endd
2840it is taken to be a normal &_.forward_& file, and is tested for validity under
2841that interpretation. See sections &<<SECTitenonfilred>>& to
2842&<<SECTspecitredli>>& for a description of the possible contents of non-filter
2843redirection lists.
2844
2845The result of an Exim command that uses &%-bf%&, provided no errors are
168e428f
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2846detected, is a list of the actions that Exim would try to take if presented
2847with the message for real. More details of filter testing are given in the
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2848separate document entitled &'Exim's interfaces to mail filtering'&.
2849
168e428f 2850When testing a filter file,
9b371988
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2851.cindex "&""From""& line"
2852.cindex "envelope sender"
f89d2485 2853.oindex "&%-f%&" "for filter testing"
9b371988
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2854the envelope sender can be set by the &%-f%& option,
2855or by a &"From&~"& line at the start of the test message. Various parameters
2856that would normally be taken from the envelope recipient address of the message
2857can be set by means of additional command line options (see the next four
2858options).
2859
2860.vitem &%-bfd%&&~<&'domain'&>
2861.oindex "&%-bfd%&"
f89d2485 2862.vindex "&$qualify_domain$&"
168e428f 2863This sets the domain of the recipient address when a filter file is being
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2864tested by means of the &%-bf%& option. The default is the value of
2865&$qualify_domain$&.
168e428f 2866
9b371988
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2867.vitem &%-bfl%&&~<&'local&~part'&>
2868.oindex "&%-bfl%&"
168e428f 2869This sets the local part of the recipient address when a filter file is being
9b371988 2870tested by means of the &%-bf%& option. The default is the username of the
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2871process that calls Exim. A local part should be specified with any prefix or
2872suffix stripped, because that is how it appears to the filter when a message is
2873actually being delivered.
2874
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2875.vitem &%-bfp%&&~<&'prefix'&>
2876.oindex "&%-bfp%&"
168e428f 2877This sets the prefix of the local part of the recipient address when a filter
9b371988 2878file is being tested by means of the &%-bf%& option. The default is an empty
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2879prefix.
2880
9b371988
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2881.vitem &%-bfs%&&~<&'suffix'&>
2882.oindex "&%-bfs%&"
168e428f 2883This sets the suffix of the local part of the recipient address when a filter
9b371988 2884file is being tested by means of the &%-bf%& option. The default is an empty
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2885suffix.
2886
9b371988
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2887.vitem &%-bh%&&~<&'IP&~address'&>
2888.oindex "&%-bh%&"
2889.cindex "testing" "incoming SMTP"
2890.cindex "SMTP" "testing incoming"
2891.cindex "testing" "relay control"
2892.cindex "relaying" "testing configuration"
2893.cindex "policy control" "testing"
2894.cindex "debugging" "&%-bh%& option"
168e428f
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2895This option runs a fake SMTP session as if from the given IP address, using the
2896standard input and output. The IP address may include a port number at the end,
2897after a full stop. For example:
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2898.code
2899exim -bh 10.9.8.7.1234
2900exim -bh fe80::a00:20ff:fe86:a061.5678
2901.endd
168e428f 2902When an IPv6 address is given, it is converted into canonical form. In the case
9b371988
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2903of the second example above, the value of &$sender_host_address$& after
2904conversion to the canonical form is
2905&`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2906
168e428f 2907Comments as to what is going on are written to the standard error file. These
9b371988 2908include lines beginning with &"LOG"& for anything that would have been logged.
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2909This facility is provided for testing configuration options for incoming
2910messages, to make sure they implement the required policy. For example, you can
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2911test your relay controls using &%-bh%&.
2912
2913&*Warning 1*&:
2914.cindex "RFC 1413"
db9452a9
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2915You can test features of the configuration that rely on ident (RFC 1413)
2916information by using the &%-oMt%& option. However, Exim cannot actually perform
2917an ident callout when testing using &%-bh%& because there is no incoming SMTP
2918connection.
9b371988
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2919
2920&*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2921are also skipped when testing using &%-bh%&. If you want these callouts to
2922occur, use &%-bhc%& instead.
2923
168e428f
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2924Messages supplied during the testing session are discarded, and nothing is
2925written to any of the real log files. There may be pauses when DNS (and other)
9b371988 2926lookups are taking place, and of course these may time out. The &%-oMi%& option
db9452a9
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2927can be used to specify a specific IP interface and port if this is important,
2928and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2929session were authenticated.
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2930
2931The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
168e428f 2932output just states whether a given recipient address from a given host is
9b371988 2933acceptable or not. See section &<<SECTcheckaccess>>&.
168e428f 2934
3cb1b51e 2935Features such as authentication and encryption, where the client input is not
f89d2485
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2936plain text, cannot easily be tested with &%-bh%&. Instead, you should use a
2937specialized SMTP test program such as
3cb1b51e 2938&url(http://jetmore.org/john/code/#swaks,swaks).
3cb1b51e 2939
9b371988
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2940.vitem &%-bhc%&&~<&'IP&~address'&>
2941.oindex "&%-bhc%&"
2942This option operates in the same way as &%-bh%&, except that address
168e428f
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2943verification callouts are performed if required. This includes consulting and
2944updating the callout cache database.
2945
9b371988
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2946.vitem &%-bi%&
2947.oindex "&%-bi%&"
2948.cindex "alias file" "building"
2949.cindex "building alias file"
2950.cindex "Sendmail compatibility" "&%-bi%& option"
2951Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
168e428f 2952Exim does not have the concept of a single alias file, and so it cannot mimic
9b371988 2953this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
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2954tend to appear in various scripts such as NIS make files, so the option must be
2955recognized.
9b371988
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2956
2957If &%-bi%& is encountered, the command specified by the &%bi_command%&
168e428f 2958configuration option is run, under the uid and gid of the caller of Exim. If
9b371988
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2959the &%-oA%& option is used, its value is passed to the command as an argument.
2960The command set by &%bi_command%& may not contain arguments. The command can
2961use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2962if this is required. If the &%bi_command%& option is not set, calling Exim with
2963&%-bi%& is a no-op.
2964
12f69989 2965.new
36a3ae5f 2966. // Keep :help first, then the rest in alphabetical order
98a90c36
PP
2967.vitem &%-bI:help%&
2968.oindex "&%-bI:help%&"
2969.cindex "querying exim information"
2970We shall provide various options starting &`-bI:`& for querying Exim for
2971information. The output of many of these will be intended for machine
2972consumption. This one is not. The &%-bI:help%& option asks Exim for a
2973synopsis of supported options beginning &`-bI:`&. Use of any of these
2974options shall cause Exim to exit after producing the requested output.
2975
36a3ae5f
PP
2976.vitem &%-bI:dscp%&
2977.oindex "&%-bI:dscp%&"
2978.cindex "DSCP" "values"
2979This option causes Exim to emit an alphabetically sorted list of all
2980recognised DSCP names.
2981
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PP
2982.vitem &%-bI:sieve%&
2983.oindex "&%-bI:sieve%&"
2984.cindex "Sieve filter" "capabilities"
2985This option causes Exim to emit an alphabetically sorted list of all supported
2986Sieve protocol extensions on stdout, one per line. This is anticipated to be
2987useful for ManageSieve (RFC 5804) implementations, in providing that protocol's
2988&`SIEVE`& capability response line. As the precise list may depend upon
2989compile-time build options, which this option will adapt to, this is the only
2990way to guarantee a correct response.
12f69989 2991.wen
98a90c36 2992
9b371988
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2993.vitem &%-bm%&
2994.oindex "&%-bm%&"
2995.cindex "local message reception"
168e428f 2996This option runs an Exim receiving process that accepts an incoming,
a543079f 2997locally-generated message on the standard input. The recipients are given as the
9b371988 2998command arguments (except when &%-t%& is also present &-- see below). Each
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2999argument can be a comma-separated list of RFC 2822 addresses. This is the
3000default option for selecting the overall action of an Exim call; it is assumed
3001if no other conflicting option is present.
9b371988 3002
168e428f 3003If any addresses in the message are unqualified (have no domain), they are
9b371988
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3004qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
3005options, as appropriate. The &%-bnq%& option (see below) provides a way of
168e428f 3006suppressing this for special cases.
9b371988 3007
168e428f 3008Policy checks on the contents of local messages can be enforced by means of
9b371988
PH
3009the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
3010
3011.cindex "return code" "for &%-bm%&"
3012The return code is zero if the message is successfully accepted. Otherwise, the
3013action is controlled by the &%-oe%&&'x'& option setting &-- see below.
3014
168e428f 3015The format
9b371988
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3016.cindex "message" "format"
3017.cindex "format" "message"
3018.cindex "&""From""& line"
3019.cindex "UUCP" "&""From""& line"
3020.cindex "Sendmail compatibility" "&""From""& line"
168e428f
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3021of the message must be as defined in RFC 2822, except that, for
3022compatibility with Sendmail and Smail, a line in one of the forms
9b371988
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3023.code
3024From sender Fri Jan 5 12:55 GMT 1997
3025From sender Fri, 5 Jan 97 12:55:01
3026.endd
168e428f
PH
3027(with the weekday optional, and possibly with additional text after the date)
3028is permitted to appear at the start of the message. There appears to be no
3029authoritative specification of the format of this line. Exim recognizes it by
9b371988 3030matching against the regular expression defined by the &%uucp_from_pattern%&
168e428f 3031option, which can be changed if necessary.
9b371988 3032
f89d2485
PH
3033.oindex "&%-f%&" "overriding &""From""& line"
3034The specified sender is treated as if it were given as the argument to the
9b371988 3035&%-f%& option, but if a &%-f%& option is also present, its argument is used in
168e428f
PH
3036preference to the address taken from the message. The caller of Exim must be a
3037trusted user for the sender of a message to be set in this way.
3038
5b257915
PP
3039.vitem &%-bmalware%&&~<&'filename'&>
3040.oindex "&%-bmalware%&"
3041.cindex "testing", "malware"
3042.cindex "malware scan test"
3043This debugging option causes Exim to scan the given file,
3044using the malware scanning framework. The option of &%av_scanner%& influences
3045this option, so if &%av_scanner%&'s value is dependent upon an expansion then
3046the expansion should have defaults which apply to this invocation. ACLs are
3047not invoked, so if &%av_scanner%& references an ACL variable then that variable
3048will never be populated and &%-bmalware%& will fail.
3049
3050Exim will have changed working directory before resolving the filename, so
3051using fully qualified pathnames is advisable. Exim will be running as the Exim
3052user when it tries to open the file, rather than as the invoking user.
3053This option requires admin privileges.
3054
3055The &%-bmalware%& option will not be extended to be more generally useful,
3056there are better tools for file-scanning. This option exists to help
3057administrators verify their Exim and AV scanner configuration.
3058
9b371988
PH
3059.vitem &%-bnq%&
3060.oindex "&%-bnq%&"
f89d2485 3061.cindex "address qualification, suppressing"
168e428f
PH
3062By default, Exim automatically qualifies unqualified addresses (those
3063without domains) that appear in messages that are submitted locally (that
3064is, not over TCP/IP). This qualification applies both to addresses in
3065envelopes, and addresses in header lines. Sender addresses are qualified using
9b371988
PH
3066&%qualify_domain%&, and recipient addresses using &%qualify_recipient%& (which
3067defaults to the value of &%qualify_domain%&).
3068
3069Sometimes, qualification is not wanted. For example, if &%-bS%& (batch SMTP) is
168e428f
PH
3070being used to re-submit messages that origina