fix example line-length, add comment (openssl_options)
[exim.git] / doc / doc-docbook / spec.xfpt
CommitLineData
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1. /////////////////////////////////////////////////////////////////////////////
2. This is the primary source of the Exim Manual. It is an xfpt document that is
3. converted into DocBook XML for subsequent conversion into printing and online
4. formats. The markup used herein is "standard" xfpt markup, with some extras.
5. The markup is summarized in a file called Markup.txt.
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6.
7. WARNING: When you use the .new macro, make sure it appears *before* any
8. adjacent index items; otherwise you get an empty "paragraph" which causes
9. unwanted vertical space.
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10. /////////////////////////////////////////////////////////////////////////////
11
12.include stdflags
13.include stdmacs
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14
15. /////////////////////////////////////////////////////////////////////////////
33393583 16. This outputs the standard DocBook boilerplate.
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17. /////////////////////////////////////////////////////////////////////////////
18
33393583 19.docbook
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20
21. /////////////////////////////////////////////////////////////////////////////
22. These lines are processing instructions for the Simple DocBook Processor that
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23. Philip Hazel has developed as a less cumbersome way of making PostScript and
24. PDFs than using xmlto and fop. They will be ignored by all other XML
25. processors.
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26. /////////////////////////////////////////////////////////////////////////////
27
28.literal xml
29<?sdop
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30 foot_right_recto="&chaptertitle; (&chapternumber;)"
31 foot_right_verso="&chaptertitle; (&chapternumber;)"
3cb1b51e 32 toc_chapter_blanks="yes,yes"
595028e4 33 table_warn_overflow="overprint"
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34?>
35.literal off
9b371988 36
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37. /////////////////////////////////////////////////////////////////////////////
38. This generate the outermost <book> element that wraps then entire document.
39. /////////////////////////////////////////////////////////////////////////////
40
41.book
42
43. /////////////////////////////////////////////////////////////////////////////
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
5d758a46 48.set previousversion "4.75"
0c7e1801 49.set version "4.77"
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>
c8d52a00 173<date>06 May 2011</date>
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174<author><firstname>Exim</firstname><surname>Maintainers</surname></author>
175<authorinitials>EM</authorinitials>
9b371988 176<revhistory><revision>
0c7e1801 177 <revnumber>4.77</revnumber>
92a14cf5 178 <date>10 Oct 2011</date>
7b4c60eb 179 <authorinitials>EM</authorinitials>
9b371988 180</revision></revhistory>
fa1fce6b 181<copyright><year>2011</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"
210f147e 536The distributions are currently signed with Nigel Metheringham's GPG key. The
168e428f 537corresponding public key is available from a number of keyservers, and there is
210f147e 538also a copy in the file &_nigel-pubkey.asc_&. The signatures for the tar bundles are
168e428f 539in:
9b371988 540.display
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541&_exim-n.nn.tar.gz.asc_&
542&_exim-n.nn.tar.bz2.asc_&
9b371988 543.endd
168e428f 544For each released version, the log of changes is made separately available in a
9b371988 545separate file in the directory &_ChangeLogs_& so that it is possible to
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546find out what has changed without having to download the entire distribution.
547
9b371988 548.cindex "documentation" "available formats"
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549The main distribution contains ASCII versions of this specification and other
550documentation; other formats of the documents are available in separate files
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551inside the &_exim4_& directory of the FTP site:
552.display
553&_exim-html-n.nn.tar.gz_&
554&_exim-pdf-n.nn.tar.gz_&
555&_exim-postscript-n.nn.tar.gz_&
556&_exim-texinfo-n.nn.tar.gz_&
557.endd
558These tar files contain only the &_doc_& directory, not the complete
559distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
168e428f 560
168e428f 561
f89d2485 562.section "Limitations" "SECID6"
9b371988
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563.ilist
564.cindex "limitations of Exim"
565.cindex "bang paths" "not handled by Exim"
566Exim is designed for use as an Internet MTA, and therefore handles addresses in
567RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
568simple two-component bang paths can be converted by a straightforward rewriting
569configuration. This restriction does not prevent Exim from being interfaced to
570UUCP as a transport mechanism, provided that domain addresses are used.
571.next
572.cindex "domainless addresses"
573.cindex "address" "without domain"
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574Exim insists that every address it handles has a domain attached. For incoming
575local messages, domainless addresses are automatically qualified with a
576configured domain value. Configuration options specify from which remote
577systems unqualified addresses are acceptable. These are then qualified on
578arrival.
9b371988
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579.next
580.cindex "transport" "external"
581.cindex "external transports"
582The only external transport mechanisms that are currently implemented are SMTP
583and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
168e428f 584transport is available, and there are facilities for writing messages to files
9b371988
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585and pipes, optionally in &'batched SMTP'& format; these facilities can be used
586to send messages to other transport mechanisms such as UUCP, provided they can
587handle domain-style addresses. Batched SMTP input is also catered for.
588.next
589Exim is not designed for storing mail for dial-in hosts. When the volumes of
590such mail are large, it is better to get the messages &"delivered"& into files
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591(that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
592other means.
9b371988
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593.next
594Although Exim does have basic facilities for scanning incoming messages, these
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595are not comprehensive enough to do full virus or spam scanning. Such operations
596are best carried out using additional specialized software packages. If you
597compile Exim with the content-scanning extension, straightforward interfaces to
598a number of common scanners are provided.
9b371988 599.endlist
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600
601
f89d2485 602.section "Run time configuration" "SECID7"
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603Exim's run time configuration is held in a single text file that is divided
604into a number of sections. The entries in this file consist of keywords and
605values, in the style of Smail 3 configuration files. A default configuration
606file which is suitable for simple online installations is provided in the
9b371988 607distribution, and is described in chapter &<<CHAPdefconfil>>& below.
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608
609
f89d2485 610.section "Calling interface" "SECID8"
9b371988 611.cindex "Sendmail compatibility" "command line interface"
168e428f 612Like many MTAs, Exim has adopted the Sendmail command line interface so that it
9b371988
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613can be a straight replacement for &_/usr/lib/sendmail_& or
614&_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
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615about Sendmail in order to run Exim. For actions other than sending messages,
616Sendmail-compatible options also exist, but those that produce output (for
9b371988 617example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
168e428f 618format. There are also some additional options that are compatible with Smail
9b371988 6193, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
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620documents all Exim's command line options. This information is automatically
621made into the man page that forms part of the Exim distribution.
622
623Control of messages on the queue can be done via certain privileged command
9b371988
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624line options. There is also an optional monitor program called &'eximon'&,
625which displays current information in an X window, and which contains a menu
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626interface to Exim's command line administration options.
627
628
629
f89d2485 630.section "Terminology" "SECID9"
9b371988
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631.cindex "terminology definitions"
632.cindex "body of message" "definition of"
633The &'body'& of a message is the actual data that the sender wants to transmit.
634It is the last part of a message, and is separated from the &'header'& (see
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635below) by a blank line.
636
9b371988 637.cindex "bounce message" "definition of"
168e428f 638When a message cannot be delivered, it is normally returned to the sender in a
9b371988
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639delivery failure message or a &"non-delivery report"& (NDR). The term
640&'bounce'& is commonly used for this action, and the error reports are often
641called &'bounce messages'&. This is a convenient shorthand for &"delivery
642failure error report"&. Such messages have an empty sender address in the
643message's &'envelope'& (see below) to ensure that they cannot themselves give
644rise to further bounce messages.
645
646The term &'default'& appears frequently in this manual. It is used to qualify a
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647value which is used in the absence of any setting in the configuration. It may
648also qualify an action which is taken unless a configuration setting specifies
649otherwise.
650
9b371988 651The term &'defer'& is used when the delivery of a message to a specific
168e428f 652destination cannot immediately take place for some reason (a remote host may be
9b371988 653down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
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654until a later time.
655
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656The word &'domain'& is sometimes used to mean all but the first component of a
657host's name. It is &'not'& used in that sense here, where it normally refers to
658the part of an email address following the @ sign.
168e428f 659
f89d2485 660.cindex "envelope, definition of"
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661.cindex "sender" "definition of"
662A message in transit has an associated &'envelope'&, as well as a header and a
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663body. The envelope contains a sender address (to which bounce messages should
664be delivered), and any number of recipient addresses. References to the
665sender or the recipients of a message usually mean the addresses in the
666envelope. An MTA uses these addresses for delivery, and for returning bounce
667messages, not the addresses that appear in the header lines.
668
f89d2485 669.cindex "message" "header, definition of"
9b371988
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670.cindex "header section" "definition of"
671The &'header'& of a message is the first part of a message's text, consisting
672of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
673&'Subject:'&, etc. Long header lines can be split over several text lines by
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674indenting the continuations. The header is separated from the body by a blank
675line.
676
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677.cindex "local part" "definition of"
678.cindex "domain" "definition of"
679The term &'local part'&, which is taken from RFC 2822, is used to refer to that
168e428f 680part of an email address that precedes the @ sign. The part that follows the
9b371988 681@ sign is called the &'domain'& or &'mail domain'&.
168e428f 682
9b371988 683.cindex "local delivery" "definition of"
f89d2485 684.cindex "remote delivery, definition of"
9b371988 685The terms &'local delivery'& and &'remote delivery'& are used to distinguish
168e428f 686delivery to a file or a pipe on the local host from delivery by SMTP over
068aaea8 687TCP/IP to another host. As far as Exim is concerned, all hosts other than the
9b371988 688host it is running on are &'remote'&.
168e428f 689
9b371988
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690.cindex "return path" "definition of"
691&'Return path'& is another name that is used for the sender address in a
168e428f
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692message's envelope.
693
9b371988
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694.cindex "queue" "definition of"
695The term &'queue'& is used to refer to the set of messages awaiting delivery,
168e428f
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696because this term is in widespread use in the context of MTAs. However, in
697Exim's case the reality is more like a pool than a queue, because there is
698normally no ordering of waiting messages.
699
9b371988
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700.cindex "queue runner" "definition of"
701The term &'queue runner'& is used to describe a process that scans the queue
168e428f 702and attempts to deliver those messages whose retry times have come. This term
9b371988 703is used by other MTAs, and also relates to the command &%runq%&, but in Exim
168e428f
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704the waiting messages are normally processed in an unpredictable order.
705
9b371988
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706.cindex "spool directory" "definition of"
707The term &'spool directory'& is used for a directory in which Exim keeps the
708messages on its queue &-- that is, those that it is in the process of
168e428f 709delivering. This should not be confused with the directory in which local
9b371988
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710mailboxes are stored, which is called a &"spool directory"& by some people. In
711the Exim documentation, &"spool"& is always used in the first sense.
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712
713
714
715
716
717
9b371988
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718. ////////////////////////////////////////////////////////////////////////////
719. ////////////////////////////////////////////////////////////////////////////
168e428f 720
f89d2485 721.chapter "Incorporated code" "CHID2"
9b371988
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722.cindex "incorporated code"
723.cindex "regular expressions" "library"
724.cindex "PCRE"
168e428f
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725A number of pieces of external code are included in the Exim distribution.
726
9b371988 727.ilist
210f147e
NM
728Regular expressions are supported in the main Exim program and in the
729Exim monitor using the freely-distributable PCRE library, copyright
40df1be3
TF
730&copy; University of Cambridge. The source to PCRE is no longer shipped with
731Exim, so you will need to use the version of PCRE shipped with your system,
732or obtain and install the full version of the library from
f89d2485 733&url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
9b371988 734.next
f89d2485 735.cindex "cdb" "acknowledgment"
168e428f
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736Support for the cdb (Constant DataBase) lookup method is provided by code
737contributed by Nigel Metheringham of (at the time he contributed it) Planet
9b371988
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738Online Ltd. The implementation is completely contained within the code of Exim.
739It does not link against an external cdb library. The code contains the
740following statements:
741
742.blockquote
743Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
744
168e428f
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745This program is free software; you can redistribute it and/or modify it under
746the terms of the GNU General Public License as published by the Free Software
747Foundation; either version 2 of the License, or (at your option) any later
748version.
168e428f
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749This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
750the spec and sample code for cdb can be obtained from
f89d2485
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751&url(http://www.pobox.com/~djb/cdb.html). This implementation borrows
752some code from Dan Bernstein's implementation (which has no license
753restrictions applied to it).
9b371988
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754.endblockquote
755.next
756.cindex "SPA authentication"
757.cindex "Samba project"
758.cindex "Microsoft Secure Password Authentication"
759Client support for Microsoft's &'Secure Password Authentication'& is provided
168e428f
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760by code contributed by Marc Prud'hommeaux. Server support was contributed by
761Tom Kistner. This includes code taken from the Samba project, which is released
762under the Gnu GPL.
9b371988
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763.next
764.cindex "Cyrus"
765.cindex "&'pwcheck'& daemon"
766.cindex "&'pwauthd'& daemon"
767Support for calling the Cyrus &'pwcheck'& and &'saslauthd'& daemons is provided
168e428f
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768by code taken from the Cyrus-SASL library and adapted by Alexander S.
769Sabourenkov. The permission notice appears below, in accordance with the
770conditions expressed therein.
9b371988
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771
772.blockquote
773Copyright &copy; 2001 Carnegie Mellon University. All rights reserved.
774
168e428f
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775Redistribution and use in source and binary forms, with or without
776modification, are permitted provided that the following conditions
777are met:
168e428f 778
9b371988
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779.olist
780Redistributions of source code must retain the above copyright
781notice, this list of conditions and the following disclaimer.
782.next
783Redistributions in binary form must reproduce the above copyright
168e428f
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784notice, this list of conditions and the following disclaimer in
785the documentation and/or other materials provided with the
786distribution.
9b371988
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787.next
788The name &"Carnegie Mellon University"& must not be used to
168e428f
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789endorse or promote products derived from this software without
790prior written permission. For permission or any other legal
791details, please contact
9b371988 792.display
068aaea8
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793 Office of Technology Transfer
794 Carnegie Mellon University
795 5000 Forbes Avenue
796 Pittsburgh, PA 15213-3890
797 (412) 268-4387, fax: (412) 268-7395
798 tech-transfer@andrew.cmu.edu
9b371988
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799.endd
800.next
801Redistributions of any form whatsoever must retain the following
168e428f 802acknowledgment:
9b371988
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803
804&"This product includes software developed by Computing Services
805at Carnegie Mellon University (&url(http://www.cmu.edu/computing/)."&
806
168e428f
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807CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
808THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
809AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
810FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
811WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
812AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
813OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
9b371988
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814.endlist
815.endblockquote
168e428f 816
9b371988 817.next
f89d2485 818.cindex "Exim monitor" "acknowledgment"
9b371988
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819.cindex "X-windows"
820.cindex "Athena"
168e428f
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821The Exim Monitor program, which is an X-Window application, includes
822modified versions of the Athena StripChart and TextPop widgets.
823This code is copyright by DEC and MIT, and their permission notice appears
824below, in accordance with the conditions expressed therein.
9b371988
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825
826.blockquote
168e428f
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827Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
828and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
9b371988 829
168e428f 830All Rights Reserved
9b371988 831
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832Permission to use, copy, modify, and distribute this software and its
833documentation for any purpose and without fee is hereby granted,
834provided that the above copyright notice appear in all copies and that
835both that copyright notice and this permission notice appear in
836supporting documentation, and that the names of Digital or MIT not be
837used in advertising or publicity pertaining to distribution of the
838software without specific, written prior permission.
9b371988 839
168e428f
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840DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
841ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
842DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
843ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
844WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
845ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
846SOFTWARE.
9b371988 847.endblockquote
168e428f 848
9b371988
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849.next
850Many people have contributed code fragments, some large, some small, that were
168e428f 851not covered by any specific licence requirements. It is assumed that the
f89d2485 852contributors are happy to see their code incorporated into Exim under the GPL.
9b371988 853.endlist
168e428f
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854
855
856
857
858
9b371988
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859. ////////////////////////////////////////////////////////////////////////////
860. ////////////////////////////////////////////////////////////////////////////
168e428f 861
f89d2485 862.chapter "How Exim receives and delivers mail" "CHID11" &&&
9b371988 863 "Receiving and delivering mail"
168e428f
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864
865
f89d2485 866.section "Overall philosophy" "SECID10"
9b371988 867.cindex "design philosophy"
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868Exim is designed to work efficiently on systems that are permanently connected
869to the Internet and are handling a general mix of mail. In such circumstances,
870most messages can be delivered immediately. Consequently, Exim does not
871maintain independent queues of messages for specific domains or hosts, though
872it does try to send several messages in a single SMTP connection after a host
873has been down, and it also maintains per-host retry information.
874
875
f89d2485 876.section "Policy control" "SECID11"
9b371988 877.cindex "policy control" "overview"
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878Policy controls are now an important feature of MTAs that are connected to the
879Internet. Perhaps their most important job is to stop MTAs being abused as
9b371988
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880&"open relays"& by misguided individuals who send out vast amounts of
881unsolicited junk, and want to disguise its source. Exim provides flexible
882facilities for specifying policy controls on incoming mail:
168e428f 883
9b371988
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884.ilist
885.cindex "&ACL;" "introduction"
168e428f 886Exim 4 (unlike previous versions of Exim) implements policy controls on
9b371988 887incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
168e428f
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888series of statements that may either grant or deny access. ACLs can be used at
889several places in the SMTP dialogue while receiving a message from a remote
9b371988
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890host. However, the most common places are after each RCPT command, and at the
891very end of the message. The sysadmin can specify conditions for accepting or
892rejecting individual recipients or the entire message, respectively, at these
893two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
168e428f 894error code.
9b371988
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895.next
896An ACL is also available for locally generated, non-SMTP messages. In this
168e428f 897case, the only available actions are to accept or deny the entire message.
9b371988
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898.next
899When Exim is compiled with the content-scanning extension, facilities are
168e428f
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900provided in the ACL mechanism for passing the message to external virus and/or
901spam scanning software. The result of such a scan is passed back to the ACL,
902which can then use it to decide what to do with the message.
9b371988
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903.next
904When a message has been received, either from a remote host or from the local
f89d2485 905host, but before the final acknowledgment has been sent, a locally supplied C
9b371988
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906function called &[local_scan()]& can be run to inspect the message and decide
907whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
908is accepted, the list of recipients can be modified by the function.
909.next
910Using the &[local_scan()]& mechanism is another way of calling external scanner
911software. The &%SA-Exim%& add-on package works this way. It does not require
912Exim to be compiled with the content-scanning extension.
913.next
914After a message has been accepted, a further checking mechanism is available in
915the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
916runs at the start of every delivery process.
917.endlist
918
919
920
f89d2485 921.section "User filters" "SECID12"
9b371988
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922.cindex "filter" "introduction"
923.cindex "Sieve filter"
168e428f 924In a conventional Exim configuration, users are able to run private filters by
9b371988
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925setting up appropriate &_.forward_& files in their home directories. See
926chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
927configuration needed to support this, and the separate document entitled
928&'Exim's interfaces to mail filtering'& for user details. Two different kinds
929of filtering are available:
930
931.ilist
932Sieve filters are written in the standard filtering language that is defined
168e428f 933by RFC 3028.
9b371988
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934.next
935Exim filters are written in a syntax that is unique to Exim, but which is more
168e428f 936powerful than Sieve, which it pre-dates.
9b371988 937.endlist
168e428f
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938
939User filters are run as part of the routing process, described below.
940
941
942
9b371988
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943.section "Message identification" "SECTmessiden"
944.cindex "message ids" "details of format"
945.cindex "format" "of message id"
946.cindex "id of message"
947.cindex "base62"
948.cindex "base36"
949.cindex "Darwin"
950.cindex "Cygwin"
951Every message handled by Exim is given a &'message id'& which is sixteen
168e428f 952characters long. It is divided into three parts, separated by hyphens, for
9b371988 953example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
168e428f
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954normally encoding numbers in base 62. However, in the Darwin operating
955system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
956(avoiding the use of lower case letters) is used instead, because the message
957id is used to construct file names, and the names of files in those systems are
068aaea8 958not always case-sensitive.
168e428f 959
9b371988 960.cindex "pid (process id)" "re-use of"
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961The detail of the contents of the message id have changed as Exim has evolved.
962Earlier versions relied on the operating system not re-using a process id (pid)
963within one second. On modern operating systems, this assumption can no longer
964be made, so the algorithm had to be changed. To retain backward compatibility,
965the format of the message id was retained, which is why the following rules are
966somewhat eccentric:
967
9b371988
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968.ilist
969The first six characters of the message id are the time at which the message
168e428f
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970started to be received, to a granularity of one second. That is, this field
971contains the number of seconds since the start of the epoch (the normal Unix
972way of representing the date and time of day).
9b371988
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973.next
974After the first hyphen, the next six characters are the id of the process that
168e428f 975received the message.
9b371988
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976.next
977There are two different possibilities for the final two characters:
978.olist
0a4e3112 979.oindex "&%localhost_number%&"
9b371988 980If &%localhost_number%& is not set, this value is the fractional part of the
168e428f
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981time of reception, normally in units of 1/2000 of a second, but for systems
982that must use base 36 instead of base 62 (because of case-insensitive file
983systems), the units are 1/1000 of a second.
9b371988
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984.next
985If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
168e428f
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986the fractional part of the time, which in this case is in units of 1/200
987(1/100) of a second.
9b371988
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988.endlist
989.endlist
168e428f
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990
991After a message has been received, Exim waits for the clock to tick at the
992appropriate resolution before proceeding, so that if another message is
993received by the same process, or by another process with the same (re-used)
994pid, it is guaranteed that the time will be different. In most cases, the clock
995will already have ticked while the message was being received.
996
997
f89d2485 998.section "Receiving mail" "SECID13"
9b371988
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999.cindex "receiving mail"
1000.cindex "message" "reception"
068aaea8
PH
1001The only way Exim can receive mail from another host is using SMTP over
1002TCP/IP, in which case the sender and recipient addresses are transferred using
168e428f
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1003SMTP commands. However, from a locally running process (such as a user's MUA),
1004there are several possibilities:
1005
9b371988
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1006.ilist
1007If the process runs Exim with the &%-bm%& option, the message is read
168e428f 1008non-interactively (usually via a pipe), with the recipients taken from the
9b371988
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1009command line, or from the body of the message if &%-t%& is also used.
1010.next
1011If the process runs Exim with the &%-bS%& option, the message is also read
168e428f
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1012non-interactively, but in this case the recipients are listed at the start of
1013the message in a series of SMTP RCPT commands, terminated by a DATA
9b371988 1014command. This is so-called &"batch SMTP"& format,
168e428f
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1015but it isn't really SMTP. The SMTP commands are just another way of passing
1016envelope addresses in a non-interactive submission.
9b371988
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1017.next
1018If the process runs Exim with the &%-bs%& option, the message is read
168e428f
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1019interactively, using the SMTP protocol. A two-way pipe is normally used for
1020passing data between the local process and the Exim process.
9b371988 1021This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
168e428f 1022example, the ACLs for SMTP commands are used for this form of submission.
9b371988
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1023.next
1024A local process may also make a TCP/IP call to the host's loopback address
168e428f
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1025(127.0.0.1) or any other of its IP addresses. When receiving messages, Exim
1026does not treat the loopback address specially. It treats all such connections
1027in the same way as connections from other hosts.
9b371988 1028.endlist
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1029
1030
f89d2485 1031.cindex "message sender, constructed by Exim"
9b371988 1032.cindex "sender" "constructed by Exim"
168e428f
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1033In the three cases that do not involve TCP/IP, the sender address is
1034constructed from the login name of the user that called Exim and a default
9b371988 1035qualification domain (which can be set by the &%qualify_domain%& configuration
168e428f
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1036option). For local or batch SMTP, a sender address that is passed using the
1037SMTP MAIL command is ignored. However, the system administrator may allow
9b371988 1038certain users (&"trusted users"&) to specify a different sender address
168e428f 1039unconditionally, or all users to specify certain forms of different sender
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1040address. The &%-f%& option or the SMTP MAIL command is used to specify these
1041different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1042users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
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1043users to change sender addresses.
1044
1045Messages received by either of the non-interactive mechanisms are subject to
1046checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1047(either over TCP/IP, or interacting with a local process) can be checked by a
1048number of ACLs that operate at different times during the SMTP session. Either
1049individual recipients, or the entire message, can be rejected if local policy
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1050requirements are not met. The &[local_scan()]& function (see chapter
1051&<<CHAPlocalscan>>&) is run for all incoming messages.
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1052
1053Exim can be configured not to start a delivery process when a message is
1054received; this can be unconditional, or depend on the number of incoming SMTP
1055connections or the system load. In these situations, new messages wait on the
1056queue until a queue runner process picks them up. However, in standard
1057configurations under normal conditions, delivery is started as soon as a
1058message is received.
1059
1060
1061
1062
1063
f89d2485 1064.section "Handling an incoming message" "SECID14"
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1065.cindex "spool directory" "files that hold a message"
1066.cindex "file" "how a message is held"
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1067When Exim accepts a message, it writes two files in its spool directory. The
1068first contains the envelope information, the current status of the message, and
1069the header lines, and the second contains the body of the message. The names of
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1070the two spool files consist of the message id, followed by &`-H`& for the
1071file containing the envelope and header, and &`-D`& for the data file.
168e428f 1072
9b371988 1073.cindex "spool directory" "&_input_& sub-directory"
168e428f 1074By default all these message files are held in a single directory called
9b371988 1075&_input_& inside the general Exim spool directory. Some operating systems do
c0712871 1076not perform very well if the number of files in a directory gets large; to
9b371988 1077improve performance in such cases, the &%split_spool_directory%& option can be
168e428f 1078used. This causes Exim to split up the input files into 62 sub-directories
db9452a9 1079whose names are single letters or digits. When this is done, the queue is
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1080processed one sub-directory at a time instead of all at once, which can improve
1081overall performance even when there are not enough files in each directory to
db9452a9 1082affect file system performance.
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1083
1084The envelope information consists of the address of the message's sender and
1085the addresses of the recipients. This information is entirely separate from
1086any addresses contained in the header lines. The status of the message includes
1087a list of recipients who have already received the message. The format of the
9b371988 1088first spool file is described in chapter &<<CHAPspool>>&.
168e428f 1089
9b371988 1090.cindex "rewriting" "addresses"
168e428f 1091Address rewriting that is specified in the rewrite section of the configuration
9b371988 1092(see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
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1093both in the header lines and the envelope, at the time the message is accepted.
1094If during the course of delivery additional addresses are generated (for
1095example, via aliasing), these new addresses are rewritten as soon as they are
1096generated. At the time a message is actually delivered (transported) further
1097rewriting can take place; because this is a transport option, it can be
1098different for different forms of delivery. It is also possible to specify the
1099addition or removal of certain header lines at the time the message is
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1100delivered (see chapters &<<CHAProutergeneric>>& and
1101&<<CHAPtransportgeneric>>&).
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1102
1103
1104
f89d2485 1105.section "Life of a message" "SECID15"
9b371988
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1106.cindex "message" "life of"
1107.cindex "message" "frozen"
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1108A message remains in the spool directory until it is completely delivered to
1109its recipients or to an error address, or until it is deleted by an
1110administrator or by the user who originally created it. In cases when delivery
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1111cannot proceed &-- for example, when a message can neither be delivered to its
1112recipients nor returned to its sender, the message is marked &"frozen"& on the
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1113spool, and no more deliveries are attempted.
1114
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1115.cindex "frozen messages" "thawing"
1116.cindex "message" "thawing frozen"
1117An administrator can &"thaw"& such messages when the problem has been
1118corrected, and can also freeze individual messages by hand if necessary. In
1119addition, an administrator can force a delivery error, causing a bounce message
1120to be sent.
1121
0a4e3112
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1122.oindex "&%timeout_frozen_after%&"
1123.oindex "&%ignore_bounce_errors_after%&"
9b371988
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1124There are options called &%ignore_bounce_errors_after%& and
1125&%timeout_frozen_after%&, which discard frozen messages after a certain time.
068aaea8 1126The first applies only to frozen bounces, the second to any frozen messages.
168e428f 1127
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1128.cindex "message" "log file for"
1129.cindex "log" "file for each message"
168e428f 1130While Exim is working on a message, it writes information about each delivery
068aaea8 1131attempt to its main log file. This includes successful, unsuccessful, and
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1132delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1133lines are also written to a separate &'message log'& file for each message.
1134These logs are solely for the benefit of the administrator, and are normally
1135deleted along with the spool files when processing of a message is complete.
168e428f 1136The use of individual message logs can be disabled by setting
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1137&%no_message_logs%&; this might give an improvement in performance on very busy
1138systems.
168e428f 1139
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1140.cindex "journal file"
1141.cindex "file" "journal"
168e428f
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1142All the information Exim itself needs to set up a delivery is kept in the first
1143spool file, along with the header lines. When a successful delivery occurs, the
1144address is immediately written at the end of a journal file, whose name is the
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1145message id followed by &`-J`&. At the end of a delivery run, if there are some
1146addresses left to be tried again later, the first spool file (the &`-H`& file)
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1147is updated to indicate which these are, and the journal file is then deleted.
1148Updating the spool file is done by writing a new file and renaming it, to
1149minimize the possibility of data loss.
1150
1151Should the system or the program crash after a successful delivery but before
1152the spool file has been updated, the journal is left lying around. The next
1153time Exim attempts to deliver the message, it reads the journal file and
1154updates the spool file before proceeding. This minimizes the chances of double
1155deliveries caused by crashes.
1156
1157
1158
9b371988
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1159.section "Processing an address for delivery" "SECTprocaddress"
1160.cindex "drivers" "definition of"
1161.cindex "router" "definition of"
1162.cindex "transport" "definition of"
1163The main delivery processing elements of Exim are called &'routers'& and
1164&'transports'&, and collectively these are known as &'drivers'&. Code for a
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1165number of them is provided in the source distribution, and compile-time options
1166specify which ones are included in the binary. Run time options specify which
1167ones are actually used for delivering messages.
1168
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1169.cindex "drivers" "instance definition"
1170Each driver that is specified in the run time configuration is an &'instance'&
168e428f 1171of that particular driver type. Multiple instances are allowed; for example,
9b371988 1172you can set up several different &(smtp)& transports, each with different
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1173option values that might specify different ports or different timeouts. Each
1174instance has its own identifying name. In what follows we will normally use the
1175instance name when discussing one particular instance (that is, one specific
1176configuration of the driver), and the generic driver name when discussing
1177the driver's features in general.
1178
9b371988 1179A &'router'& is a driver that operates on an address, either determining how
068aaea8 1180its delivery should happen, by assigning it to a specific transport, or
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1181converting the address into one or more new addresses (for example, via an
1182alias file). A router may also explicitly choose to fail an address, causing it
1183to be bounced.
1184
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1185A &'transport'& is a driver that transmits a copy of the message from Exim's
1186spool to some destination. There are two kinds of transport: for a &'local'&
168e428f 1187transport, the destination is a file or a pipe on the local host, whereas for a
9b371988 1188&'remote'& transport the destination is some other host. A message is passed
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1189to a specific transport as a result of successful routing. If a message has
1190several recipients, it may be passed to a number of different transports.
1191
9b371988 1192.cindex "preconditions" "definition of"
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1193An address is processed by passing it to each configured router instance in
1194turn, subject to certain preconditions, until a router accepts the address or
1195specifies that it should be bounced. We will describe this process in more
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1196detail shortly. First, as a simple example, we consider how each recipient
1197address in a message is processed in a small configuration of three routers.
168e428f 1198
068aaea8 1199To make this a more concrete example, it is described in terms of some actual
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1200routers, but remember, this is only an example. You can configure Exim's
1201routers in many different ways, and there may be any number of routers in a
1202configuration.
1203
1204The first router that is specified in a configuration is often one that handles
1205addresses in domains that are not recognized specially by the local host. These
1206are typically addresses for arbitrary domains on the Internet. A precondition
1207is set up which looks for the special domains known to the host (for example,
9b371988 1208its own domain name), and the router is run for addresses that do &'not'&
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1209match. Typically, this is a router that looks up domains in the DNS in order to
1210find the hosts to which this address routes. If it succeeds, the address is
068aaea8 1211assigned to a suitable SMTP transport; if it does not succeed, the router is
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1212configured to fail the address.
1213
068aaea8 1214The second router is reached only when the domain is recognized as one that
9b371988 1215&"belongs"& to the local host. This router does redirection &-- also known as
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1216aliasing and forwarding. When it generates one or more new addresses from the
1217original, each of them is routed independently from the start. Otherwise, the
1218router may cause an address to fail, or it may simply decline to handle the
1219address, in which case the address is passed to the next router.
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1220
1221The final router in many configurations is one that checks to see if the
1222address belongs to a local mailbox. The precondition may involve a check to
1223see if the local part is the name of a login account, or it may look up the
1224local part in a file or a database. If its preconditions are not met, or if
1225the router declines, we have reached the end of the routers. When this happens,
1226the address is bounced.
1227
1228
1229
f89d2485 1230.section "Processing an address for verification" "SECID16"
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1231.cindex "router" "for verification"
1232.cindex "verifying address" "overview"
168e428f 1233As well as being used to decide how to deliver to an address, Exim's routers
9b371988 1234are also used for &'address verification'&. Verification can be requested as
168e428f 1235one of the checks to be performed in an ACL for incoming messages, on both
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1236sender and recipient addresses, and it can be tested using the &%-bv%& and
1237&%-bvs%& command line options.
168e428f 1238
9b371988 1239When an address is being verified, the routers are run in &"verify mode"&. This
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1240does not affect the way the routers work, but it is a state that can be
1241detected. By this means, a router can be skipped or made to behave differently
1242when verifying. A common example is a configuration in which the first router
1243sends all messages to a message-scanning program, unless they have been
1244previously scanned. Thus, the first router accepts all addresses without any
9b371988 1245checking, making it useless for verifying. Normally, the &%no_verify%& option
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1246would be set for such a router, causing it to be skipped in verify mode.
1247
1248
1249
1250
9b371988
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1251.section "Running an individual router" "SECTrunindrou"
1252.cindex "router" "running details"
1253.cindex "preconditions" "checking"
1254.cindex "router" "result of running"
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1255As explained in the example above, a number of preconditions are checked before
1256running a router. If any are not met, the router is skipped, and the address is
9b371988 1257passed to the next router. When all the preconditions on a router &'are'& met,
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1258the router is run. What happens next depends on the outcome, which is one of
1259the following:
1260
9b371988
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1261.ilist
1262&'accept'&: The router accepts the address, and either assigns it to a
1263transport, or generates one or more &"child"& addresses. Processing the
1264original address ceases,
0a4e3112 1265.oindex "&%unseen%&"
9b371988 1266unless the &%unseen%& option is set on the router. This option
168e428f 1267can be used to set up multiple deliveries with different routing (for example,
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1268for keeping archive copies of messages). When &%unseen%& is set, the address is
1269passed to the next router. Normally, however, an &'accept'& return marks the
168e428f 1270end of routing.
9b371988 1271
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1272Any child addresses generated by the router are processed independently,
1273starting with the first router by default. It is possible to change this by
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1274setting the &%redirect_router%& option to specify which router to start at for
1275child addresses. Unlike &%pass_router%& (see below) the router specified by
1276&%redirect_router%& may be anywhere in the router configuration.
1277.next
1278&'pass'&: The router recognizes the address, but cannot handle it itself. It
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1279requests that the address be passed to another router. By default the address
1280is passed to the next router, but this can be changed by setting the
9b371988 1281&%pass_router%& option. However, (unlike &%redirect_router%&) the named router
168e428f 1282must be below the current router (to avoid loops).
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1283.next
1284&'decline'&: The router declines to accept the address because it does not
168e428f 1285recognize it at all. By default, the address is passed to the next router, but
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1286this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1287set, all the remaining routers are skipped. In effect, &%no_more%& converts
1288&'decline'& into &'fail'&.
1289.next
1290&'fail'&: The router determines that the address should fail, and queues it for
168e428f 1291the generation of a bounce message. There is no further processing of the
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1292original address unless &%unseen%& is set on the router.
1293.next
1294&'defer'&: The router cannot handle the address at the present time. (A
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1295database may be offline, or a DNS lookup may have timed out.) No further
1296processing of the address happens in this delivery attempt. It is tried again
1297next time the message is considered for delivery.
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1298.next
1299&'error'&: There is some error in the router (for example, a syntax error in
168e428f 1300its configuration). The action is as for defer.
9b371988 1301.endlist
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1302
1303If an address reaches the end of the routers without having been accepted by
068aaea8 1304any of them, it is bounced as unrouteable. The default error message in this
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1305situation is &"unrouteable address"&, but you can set your own message by
1306making use of the &%cannot_route_message%& option. This can be set for any
1307router; the value from the last router that &"saw"& the address is used.
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1308
1309Sometimes while routing you want to fail a delivery when some conditions are
1310met but others are not, instead of passing the address on for further routing.
1311You can do this by having a second router that explicitly fails the delivery
9b371988 1312when the relevant conditions are met. The &(redirect)& router has a &"fail"&
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1313facility for this purpose.
1314
1315
f89d2485 1316.section "Duplicate addresses" "SECID17"
9b371988 1317.cindex "case of local parts"
f89d2485 1318.cindex "address duplicate, discarding"
db9452a9 1319.cindex "duplicate addresses"
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1320Once routing is complete, Exim scans the addresses that are assigned to local
1321and remote transports, and discards any duplicates that it finds. During this
3cb1b51e 1322check, local parts are treated as case-sensitive. This happens only when
db9452a9 1323actually delivering a message; when testing routers with &%-bt%&, all the
3cb1b51e 1324routed addresses are shown.
db9452a9 1325
068aaea8 1326
168e428f 1327
9b371988 1328.section "Router preconditions" "SECTrouprecon"
f89d2485 1329.cindex "router" "preconditions, order of processing"
9b371988 1330.cindex "preconditions" "order of processing"
168e428f
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1331The preconditions that are tested for each router are listed below, in the
1332order in which they are tested. The individual configuration options are
9b371988 1333described in more detail in chapter &<<CHAProutergeneric>>&.
168e428f 1334
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1335.ilist
1336The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
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1337the local parts handled by the router may or must have certain prefixes and/or
1338suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1339skipped. These conditions are tested first. When an affix is present, it is
1340removed from the local part before further processing, including the evaluation
1341of any other conditions.
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1342.next
1343Routers can be designated for use only when not verifying an address, that is,
168e428f 1344only when routing it for delivery (or testing its delivery routing). If the
9b371988 1345&%verify%& option is set false, the router is skipped when Exim is verifying an
168e428f 1346address.
9b371988
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1347Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1348&%verify_recipient%&, which independently control the use of the router for
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1349sender and recipient verification. You can set these options directly if
1350you want a router to be used for only one type of verification.
9b371988
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1351.next
1352If the &%address_test%& option is set false, the router is skipped when Exim is
1353run with the &%-bt%& option to test an address routing. This can be helpful
1354when the first router sends all new messages to a scanner of some sort; it
1355makes it possible to use &%-bt%& to test subsequent delivery routing without
1356having to simulate the effect of the scanner.
1357.next
1358Routers can be designated for use only when verifying an address, as
1359opposed to routing it for delivery. The &%verify_only%& option controls this.
1360.next
1361Individual routers can be explicitly skipped when running the routers to
1362check an address given in the SMTP EXPN command (see the &%expn%& option).
1363.next
1364If the &%domains%& option is set, the domain of the address must be in the set
068aaea8 1365of domains that it defines.
9b371988 1366.next
f89d2485
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1367.vindex "&$local_part_prefix$&"
1368.vindex "&$local_part$&"
1369.vindex "&$local_part_suffix$&"
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1370If the &%local_parts%& option is set, the local part of the address must be in
1371the set of local parts that it defines. If &%local_part_prefix%& or
1372&%local_part_suffix%& is in use, the prefix or suffix is removed from the local
168e428f 1373part before this check. If you want to do precondition tests on local parts
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1374that include affixes, you can do so by using a &%condition%& option (see below)
1375that uses the variables &$local_part$&, &$local_part_prefix$&, and
1376&$local_part_suffix$& as necessary.
1377.next
f89d2485
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1378.vindex "&$local_user_uid$&"
1379.vindex "&$local_user_gid$&"
1380.vindex "&$home$&"
9b371988 1381If the &%check_local_user%& option is set, the local part must be the name of
068aaea8 1382an account on the local host. If this check succeeds, the uid and gid of the
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1383local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1384user's home directory is placed in &$home$&; these values can be used in the
1385remaining preconditions.
1386.next
1387If the &%router_home_directory%& option is set, it is expanded at this point,
1388because it overrides the value of &$home$&. If this expansion were left till
1389later, the value of &$home$& as set by &%check_local_user%& would be used in
1390subsequent tests. Having two different values of &$home$& in the same router
168e428f 1391could lead to confusion.
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1392.next
1393If the &%senders%& option is set, the envelope sender address must be in the
1394set of addresses that it defines.
1395.next
1396If the &%require_files%& option is set, the existence or non-existence of
168e428f 1397specified files is tested.
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1398.next
1399.cindex "customizing" "precondition"
1400If the &%condition%& option is set, it is evaluated and tested. This option
1401uses an expanded string to allow you to set up your own custom preconditions.
1402Expanded strings are described in chapter &<<CHAPexpand>>&.
1403.endlist
168e428f 1404
168e428f 1405
9b371988
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1406Note that &%require_files%& comes near the end of the list, so you cannot use
1407it to check for the existence of a file in which to lookup up a domain, local
168e428f 1408part, or sender. However, as these options are all expanded, you can use the
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1409&%exists%& expansion condition to make such tests within each condition. The
1410&%require_files%& option is intended for checking files that the router may be
168e428f 1411going to use internally, or which are needed by a specific transport (for
9b371988 1412example, &_.procmailrc_&).
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1413
1414
1415
f89d2485 1416.section "Delivery in detail" "SECID18"
9b371988 1417.cindex "delivery" "in detail"
168e428f
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1418When a message is to be delivered, the sequence of events is as follows:
1419
9b371988
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1420.ilist
1421If a system-wide filter file is specified, the message is passed to it. The
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1422filter may add recipients to the message, replace the recipients, discard the
1423message, cause a new message to be generated, or cause the message delivery to
1424fail. The format of the system filter file is the same as for Exim user filter
9b371988
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1425files, described in the separate document entitled &'Exim's interfaces to mail
1426filtering'&.
1427.cindex "Sieve filter" "not available for system filter"
1428(&*Note*&: Sieve cannot be used for system filter files.)
1429
1430Some additional features are available in system filters &-- see chapter
1431&<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
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1432filter only once per delivery attempt, however many recipients it has. However,
1433if there are several delivery attempts because one or more addresses could not
1434be immediately delivered, the system filter is run each time. The filter
9b371988 1435condition &%first_delivery%& can be used to detect the first run of the system
168e428f 1436filter.
9b371988
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1437.next
1438Each recipient address is offered to each configured router in turn, subject to
1439its preconditions, until one is able to handle it. If no router can handle the
1440address, that is, if they all decline, the address is failed. Because routers
1441can be targeted at particular domains, several locally handled domains can be
1442processed entirely independently of each other.
1443.next
1444.cindex "routing" "loops in"
1445.cindex "loop" "while routing"
1446A router that accepts an address may assign it to a local or a remote
1447transport. However, the transport is not run at this time. Instead, the address
1448is placed on a list for the particular transport, which will be run later.
068aaea8
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1449Alternatively, the router may generate one or more new addresses (typically
1450from alias, forward, or filter files). New addresses are fed back into this
1451process from the top, but in order to avoid loops, a router ignores any address
1452which has an identically-named ancestor that was processed by itself.
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1453.next
1454When all the routing has been done, addresses that have been successfully
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1455handled are passed to their assigned transports. When local transports are
1456doing real local deliveries, they handle only one address at a time, but if a
1457local transport is being used as a pseudo-remote transport (for example, to
1458collect batched SMTP messages for transmission by some other means) multiple
1459addresses can be handled. Remote transports can always handle more than one
1460address at a time, but can be configured not to do so, or to restrict multiple
1461addresses to the same domain.
9b371988
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1462.next
1463Each local delivery to a file or a pipe runs in a separate process under a
168e428f
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1464non-privileged uid, and these deliveries are run one at a time. Remote
1465deliveries also run in separate processes, normally under a uid that is private
9b371988 1466to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
168e428f 1467run in parallel. The maximum number of simultaneous remote deliveries for any
9b371988 1468one message is set by the &%remote_max_parallel%& option.
168e428f
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1469The order in which deliveries are done is not defined, except that all local
1470deliveries happen before any remote deliveries.
9b371988
PH
1471.next
1472.cindex "queue runner"
168e428f
PH
1473When it encounters a local delivery during a queue run, Exim checks its retry
1474database to see if there has been a previous temporary delivery failure for the
1475address before running the local transport. If there was a previous failure,
1476Exim does not attempt a new delivery until the retry time for the address is
1477reached. However, this happens only for delivery attempts that are part of a
1478queue run. Local deliveries are always attempted when delivery immediately
1479follows message reception, even if retry times are set for them. This makes for
1480better behaviour if one particular message is causing problems (for example,
1481causing quota overflow, or provoking an error in a filter file).
9b371988
PH
1482.next
1483.cindex "delivery" "retry in remote transports"
168e428f
PH
1484Remote transports do their own retry handling, since an address may be
1485deliverable to one of a number of hosts, each of which may have a different
1486retry time. If there have been previous temporary failures and no host has
1487reached its retry time, no delivery is attempted, whether in a queue run or
9b371988
PH
1488not. See chapter &<<CHAPretry>>& for details of retry strategies.
1489.next
1490If there were any permanent errors, a bounce message is returned to an
168e428f
PH
1491appropriate address (the sender in the common case), with details of the error
1492for each failing address. Exim can be configured to send copies of bounce
1493messages to other addresses.
9b371988
PH
1494.next
1495.cindex "delivery" "deferral"
168e428f
PH
1496If one or more addresses suffered a temporary failure, the message is left on
1497the queue, to be tried again later. Delivery of these addresses is said to be
9b371988
PH
1498&'deferred'&.
1499.next
1500When all the recipient addresses have either been delivered or bounced,
168e428f
PH
1501handling of the message is complete. The spool files and message log are
1502deleted, though the message log can optionally be preserved if required.
9b371988 1503.endlist
168e428f
PH
1504
1505
1506
1507
f89d2485 1508.section "Retry mechanism" "SECID19"
9b371988
PH
1509.cindex "delivery" "retry mechanism"
1510.cindex "retry" "description of mechanism"
1511.cindex "queue runner"
168e428f
PH
1512Exim's mechanism for retrying messages that fail to get delivered at the first
1513attempt is the queue runner process. You must either run an Exim daemon that
9b371988
PH
1514uses the &%-q%& option with a time interval to start queue runners at regular
1515intervals, or use some other means (such as &'cron'&) to start them. If you do
168e428f
PH
1516not arrange for queue runners to be run, messages that fail temporarily at the
1517first attempt will remain on your queue for ever. A queue runner process works
068aaea8 1518its way through the queue, one message at a time, trying each delivery that has
168e428f
PH
1519passed its retry time.
1520You can run several queue runners at once.
1521
1522Exim uses a set of configured rules to determine when next to retry the failing
9b371988
PH
1523address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1524should give up trying to deliver to the address, at which point it generates a
1525bounce message. If no retry rules are set for a particular host, address, and
1526error combination, no retries are attempted, and temporary errors are treated
1527as permanent.
168e428f
PH
1528
1529
1530
f89d2485 1531.section "Temporary delivery failure" "SECID20"
9b371988 1532.cindex "delivery" "temporary failure"
168e428f
PH
1533There are many reasons why a message may not be immediately deliverable to a
1534particular address. Failure to connect to a remote machine (because it, or the
1535connection to it, is down) is one of the most common. Temporary failures may be
1536detected during routing as well as during the transport stage of delivery.
1537Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1538is on a file system where the user is over quota. Exim can be configured to
1539impose its own quotas on local mailboxes; where system quotas are set they will
1540also apply.
1541
1542If a host is unreachable for a period of time, a number of messages may be
1543waiting for it by the time it recovers, and sending them in a single SMTP
1544connection is clearly beneficial. Whenever a delivery to a remote host is
1545deferred,
9b371988 1546.cindex "hints database"
168e428f
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1547Exim makes a note in its hints database, and whenever a successful
1548SMTP delivery has happened, it looks to see if any other messages are waiting
1549for the same host. If any are found, they are sent over the same SMTP
1550connection, subject to a configuration limit as to the maximum number in any
1551one connection.
168e428f
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1552
1553
1554
f89d2485 1555.section "Permanent delivery failure" "SECID21"
9b371988
PH
1556.cindex "delivery" "permanent failure"
1557.cindex "bounce message" "when generated"
168e428f
PH
1558When a message cannot be delivered to some or all of its intended recipients, a
1559bounce message is generated. Temporary delivery failures turn into permanent
1560errors when their timeout expires. All the addresses that fail in a given
1561delivery attempt are listed in a single message. If the original message has
1562many recipients, it is possible for some addresses to fail in one delivery
1563attempt and others to fail subsequently, giving rise to more than one bounce
1564message. The wording of bounce messages can be customized by the administrator.
9b371988 1565See chapter &<<CHAPemsgcust>>& for details.
168e428f 1566
9b371988
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1567.cindex "&'X-Failed-Recipients:'& header line"
1568Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
168e428f
PH
1569failed addresses, for the benefit of programs that try to analyse such messages
1570automatically.
1571
9b371988 1572.cindex "bounce message" "recipient of"
168e428f
PH
1573A bounce message is normally sent to the sender of the original message, as
1574obtained from the message's envelope. For incoming SMTP messages, this is the
9b371988
PH
1575address given in the MAIL command. However, when an address is expanded via a
1576forward or alias file, an alternative address can be specified for delivery
1577failures of the generated addresses. For a mailing list expansion (see section
1578&<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1579of the list.
168e428f
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1580
1581
1582
f89d2485 1583.section "Failures to deliver bounce messages" "SECID22"
9b371988 1584.cindex "bounce message" "failure to deliver"
168e428f
PH
1585If a bounce message (either locally generated or received from a remote host)
1586itself suffers a permanent delivery failure, the message is left on the queue,
1587but it is frozen, awaiting the attention of an administrator. There are options
068aaea8 1588that can be used to make Exim discard such failed messages, or to keep them
9b371988
PH
1589for only a short time (see &%timeout_frozen_after%& and
1590&%ignore_bounce_errors_after%&).
168e428f
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1591
1592
1593
1594
1595
9b371988
PH
1596. ////////////////////////////////////////////////////////////////////////////
1597. ////////////////////////////////////////////////////////////////////////////
168e428f 1598
f89d2485 1599.chapter "Building and installing Exim" "CHID3"
4f578862 1600.scindex IIDbuex "building Exim"
168e428f 1601
f89d2485
PH
1602.section "Unpacking" "SECID23"
1603Exim is distributed as a gzipped or bzipped tar file which, when unpacked,
168e428f 1604creates a directory with the name of the current release (for example,
9b371988
PH
1605&_exim-&version;_&) into which the following files are placed:
1606
1607.table2 140pt
f89d2485
PH
1608.irow &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1609.irow &_CHANGES_& "contains a reference to where changes are &&&
1610 documented"
1611.irow &_LICENCE_& "the GNU General Public Licence"
1612.irow &_Makefile_& "top-level make file"
1613.irow &_NOTICE_& "conditions for the use of Exim"
1614.irow &_README_& "list of files, directories and simple build &&&
1615 instructions"
9b371988
PH
1616.endtable
1617
1618Other files whose names begin with &_README_& may also be present. The
168e428f
PH
1619following subdirectories are created:
1620
9b371988 1621.table2 140pt
f89d2485
PH
1622.irow &_Local_& "an empty directory for local configuration files"
1623.irow &_OS_& "OS-specific files"
1624.irow &_doc_& "documentation files"
1625.irow &_exim_monitor_& "source files for the Exim monitor"
1626.irow &_scripts_& "scripts used in the build process"
1627.irow &_src_& "remaining source files"
1628.irow &_util_& "independent utilities"
9b371988
PH
1629.endtable
1630
1631The main utility programs are contained in the &_src_& directory, and are built
1632with the Exim binary. The &_util_& directory contains a few optional scripts
168e428f
PH
1633that may be useful to some sites.
1634
1635
f89d2485 1636.section "Multiple machine architectures and operating systems" "SECID24"
9b371988 1637.cindex "building Exim" "multiple OS/architectures"
168e428f
PH
1638The building process for Exim is arranged to make it easy to build binaries for
1639a number of different architectures and operating systems from the same set of
9b371988
PH
1640source files. Compilation does not take place in the &_src_& directory.
1641Instead, a &'build directory'& is created for each architecture and operating
1642system.
1643.cindex "symbolic link" "to build directory"
168e428f 1644Symbolic links to the sources are installed in this directory, which is where
9b371988
PH
1645the actual building takes place. In most cases, Exim can discover the machine
1646architecture and operating system for itself, but the defaults can be
1647overridden if necessary.
168e428f 1648
168e428f 1649
8473d4ee 1650.section "PCRE library" "SECTpcre"
210f147e
NM
1651.cindex "PCRE library"
1652Exim no longer has an embedded PCRE library as the vast majority of
1653modern systems include PCRE as a system library, although you may need
1654to install the PCRE or PCRE development package for your operating
1655system. If your system has a normal PCRE installation the Exim build
1656process will need no further configuration. If the library or the
1657headers are in an unusual location you will need to set the PCRE_LIBS
1658and INCLUDE directives appropriately. If your operating system has no
1659PCRE support then you will need to obtain and build the current PCRE
1660from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/).
1661
9b371988
PH
1662.section "DBM libraries" "SECTdb"
1663.cindex "DBM libraries" "discussion of"
1664.cindex "hints database" "DBM files used for"
168e428f
PH
1665Even if you do not use any DBM files in your configuration, Exim still needs a
1666DBM library in order to operate, because it uses indexed files for its hints
1667databases. Unfortunately, there are a number of DBM libraries in existence, and
1668different operating systems often have different ones installed.
1669
9b371988 1670.cindex "Solaris" "DBM library for"
f89d2485
PH
1671.cindex "IRIX, DBM library for"
1672.cindex "BSD, DBM library for"
1673.cindex "Linux, DBM library for"
168e428f
PH
1674If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1675Linux distribution, the DBM configuration should happen automatically, and you
1676may be able to ignore this section. Otherwise, you may have to learn more than
1677you would like about DBM libraries from what follows.
1678
9b371988 1679.cindex "&'ndbm'& DBM library"
168e428f 1680Licensed versions of Unix normally contain a library of DBM functions operating
9b371988 1681via the &'ndbm'& interface, and this is what Exim expects by default. Free
168e428f
PH
1682versions of Unix seem to vary in what they contain as standard. In particular,
1683some early versions of Linux have no default DBM library, and different
1684distributors have chosen to bundle different libraries with their packaged
f89d2485 1685versions. However, the more recent releases seem to have standardized on the
168e428f
PH
1686Berkeley DB library.
1687
1688Different DBM libraries have different conventions for naming the files they
9b371988 1689use. When a program opens a file called &_dbmfile_&, there are several
168e428f
PH
1690possibilities:
1691
9b371988
PH
1692.olist
1693A traditional &'ndbm'& implementation, such as that supplied as part of
1694Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1695.next
1696.cindex "&'gdbm'& DBM library"
1697The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
168e428f 1698compatibility interface it makes two different hard links to it with names
9b371988 1699&_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
168e428f 1700file name is used unmodified.
9b371988
PH
1701.next
1702.cindex "Berkeley DB library"
1703The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1704operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1705programmer exactly the same as the traditional &'ndbm'& implementation.
1706.next
1707If the Berkeley package is used in its native mode, it operates on a single
1708file called &_dbmfile_&; the programmer's interface is somewhat different to
1709the traditional &'ndbm'& interface.
1710.next
1711To complicate things further, there are several very different versions of the
168e428f 1712Berkeley DB package. Version 1.85 was stable for a very long time, releases
9b371988
PH
17132.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1714numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
168e428f 1715versions of Berkeley DB can be obtained from
9b371988
PH
1716&url(http://www.sleepycat.com/).
1717.next
1718.cindex "&'tdb'& DBM library"
1719Yet another DBM library, called &'tdb'&, is available from
1720&url(http://download.sourceforge.net/tdb). It has its own interface, and also
1721operates on a single file.
1722.endlist
1723
1724.cindex "USE_DB"
1725.cindex "DBM libraries" "configuration for building"
168e428f
PH
1726Exim and its utilities can be compiled to use any of these interfaces. In order
1727to use any version of the Berkeley DB package in native mode, you must set
1728USE_DB in an appropriate configuration file (typically
9b371988
PH
1729&_Local/Makefile_&). For example:
1730.code
1731USE_DB=yes
1732.endd
168e428f
PH
1733Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1734error is diagnosed if you set more than one of these.
1735
1736At the lowest level, the build-time configuration sets none of these options,
1737thereby assuming an interface of type (1). However, some operating system
1738configuration files (for example, those for the BSD operating systems and
1739Linux) assume type (4) by setting USE_DB as their default, and the
1740configuration files for Cygwin set USE_GDBM. Anything you set in
9b371988 1741&_Local/Makefile_&, however, overrides these system defaults.
168e428f
PH
1742
1743As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1744necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1745in one of these lines:
9b371988
PH
1746.code
1747DBMLIB = -ldb
1748DBMLIB = -ltdb
1749.endd
168e428f
PH
1750Settings like that will work if the DBM library is installed in the standard
1751place. Sometimes it is not, and the library's header file may also not be in
1752the default path. You may need to set INCLUDE to specify where the header
1753file is, and to specify the path to the library more fully in DBMLIB, as in
1754this example:
9b371988
PH
1755.code
1756INCLUDE=-I/usr/local/include/db-4.1
1757DBMLIB=/usr/local/lib/db-4.1/libdb.a
1758.endd
168e428f 1759There is further detailed discussion about the various DBM libraries in the
9b371988 1760file &_doc/dbm.discuss.txt_& in the Exim distribution.
168e428f
PH
1761
1762
1763
f89d2485 1764.section "Pre-building configuration" "SECID25"
9b371988
PH
1765.cindex "building Exim" "pre-building configuration"
1766.cindex "configuration for building Exim"
1767.cindex "&_Local/Makefile_&"
1768.cindex "&_src/EDITME_&"
168e428f
PH
1769Before building Exim, a local configuration file that specifies options
1770independent of any operating system has to be created with the name
9b371988
PH
1771&_Local/Makefile_&. A template for this file is supplied as the file
1772&_src/EDITME_&, and it contains full descriptions of all the option settings
168e428f
PH
1773therein. These descriptions are therefore not repeated here. If you are
1774building Exim for the first time, the simplest thing to do is to copy
9b371988 1775&_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
168e428f
PH
1776
1777There are three settings that you must supply, because Exim will not build
1778without them. They are the location of the run time configuration file
1779(CONFIGURE_FILE), the directory in which Exim binaries will be installed
1780(BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1781maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1782a colon-separated list of file names; Exim uses the first of them that exists.
1783
1784There are a few other parameters that can be specified either at build time or
1785at run time, to enable the same binary to be used on a number of different
1786machines. However, if the locations of Exim's spool directory and log file
1787directory (if not within the spool directory) are fixed, it is recommended that
9b371988 1788you specify them in &_Local/Makefile_& instead of at run time, so that errors
168e428f
PH
1789detected early in Exim's execution (such as a malformed configuration file) can
1790be logged.
1791
9b371988 1792.cindex "content scanning" "specifying at build time"
068aaea8 1793Exim's interfaces for calling virus and spam scanning software directly from
168e428f
PH
1794access control lists are not compiled by default. If you want to include these
1795facilities, you need to set
9b371988
PH
1796.code
1797WITH_CONTENT_SCAN=yes
1798.endd
1799in your &_Local/Makefile_&. For details of the facilities themselves, see
1800chapter &<<CHAPexiscan>>&.
168e428f
PH
1801
1802
9b371988 1803.cindex "&_Local/eximon.conf_&"
3cb1b51e 1804.cindex "&_exim_monitor/EDITME_&"
168e428f 1805If you are going to build the Exim monitor, a similar configuration process is
9b371988
PH
1806required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1807your installation and saved under the name &_Local/eximon.conf_&. If you are
1808happy with the default settings described in &_exim_monitor/EDITME_&,
1809&_Local/eximon.conf_& can be empty, but it must exist.
168e428f
PH
1810
1811This is all the configuration that is needed in straightforward cases for known
1812operating systems. However, the building process is set up so that it is easy
1813to override options that are set by default or by operating-system-specific
1814configuration files, for example to change the name of the C compiler, which
9b371988
PH
1815defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1816do this.
168e428f
PH
1817
1818
1819
f89d2485 1820.section "Support for iconv()" "SECID26"
9b371988
PH
1821.cindex "&[iconv()]& support"
1822.cindex "RFC 2047"
168e428f
PH
1823The contents of header lines in messages may be encoded according to the rules
1824described RFC 2047. This makes it possible to transmit characters that are not
1825in the ASCII character set, and to label them as being in a particular
9b371988 1826character set. When Exim is inspecting header lines by means of the &%$h_%&
168e428f
PH
1827mechanism, it decodes them, and translates them into a specified character set
1828(default ISO-8859-1). The translation is possible only if the operating system
9b371988
PH
1829supports the &[iconv()]& function.
1830
1831However, some of the operating systems that supply &[iconv()]& do not support
1832very many conversions. The GNU &%libiconv%& library (available from
1833&url(http://www.gnu.org/software/libiconv/)) can be installed on such
1834systems to remedy this deficiency, as well as on systems that do not supply
1835&[iconv()]& at all. After installing &%libiconv%&, you should add
1836.code
1837HAVE_ICONV=yes
1838.endd
1839to your &_Local/Makefile_& and rebuild Exim.
1840
1841
1842
1843.section "Including TLS/SSL encryption support" "SECTinctlsssl"
1844.cindex "TLS" "including support for TLS"
1845.cindex "encryption" "including support for"
1846.cindex "SUPPORT_TLS"
1847.cindex "OpenSSL" "building Exim with"
1848.cindex "GnuTLS" "building Exim with"
168e428f
PH
1849Exim can be built to support encrypted SMTP connections, using the STARTTLS
1850command as per RFC 2487. It can also support legacy clients that expect to
1851start a TLS session immediately on connection to a non-standard port (see the
9b371988 1852&%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
168e428f
PH
1853line option).
1854
1855If you want to build Exim with TLS support, you must first install either the
1856OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1857implementing SSL.
1858
1859If OpenSSL is installed, you should set
9b371988
PH
1860.code
1861SUPPORT_TLS=yes
1862TLS_LIBS=-lssl -lcrypto
1863.endd
1864in &_Local/Makefile_&. You may also need to specify the locations of the
168e428f 1865OpenSSL library and include files. For example:
9b371988
PH
1866.code
1867SUPPORT_TLS=yes
1868TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1869TLS_INCLUDE=-I/usr/local/openssl/include/
1870.endd
7e6a8985
PP
1871.new
1872.cindex "pkg-config" "OpenSSL"
1873If you have &'pkg-config'& available, then instead you can just use:
1874.code
1875SUPPORT_TLS=yes
1876USE_OPENSSL_PC=openssl
1877.endd
1878.wen
9b371988 1879.cindex "USE_GNUTLS"
168e428f 1880If GnuTLS is installed, you should set
9b371988
PH
1881.code
1882SUPPORT_TLS=yes
1883USE_GNUTLS=yes
1884TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1885.endd
1886in &_Local/Makefile_&, and again you may need to specify the locations of the
168e428f 1887library and include files. For example:
9b371988
PH
1888.code
1889SUPPORT_TLS=yes
1890USE_GNUTLS=yes
1891TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1892TLS_INCLUDE=-I/usr/gnu/include
1893.endd
7e6a8985
PP
1894.new
1895.cindex "pkg-config" "GnuTLS"
1896If you have &'pkg-config'& available, then instead you can just use:
1897.code
1898SUPPORT_TLS=yes
1899USE_GNUTLS=yes
1900USE_GNUTLS_PC=gnutls
1901.endd
1902.wen
1903
168e428f 1904You do not need to set TLS_INCLUDE if the relevant directory is already
9b371988
PH
1905specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1906given in chapter &<<CHAPTLS>>&.
168e428f
PH
1907
1908
1909
1910
b52ed2b3
NM
1911.section "Use of tcpwrappers" "SECID27"
1912
f89d2485 1913.cindex "tcpwrappers, building Exim to support"
9b371988 1914.cindex "USE_TCP_WRAPPERS"
5dc43717
JJ
1915.cindex "TCP_WRAPPERS_DAEMON_NAME"
1916.cindex "tcp_wrappers_daemon_name"
9b371988
PH
1917Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1918SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
168e428f 1919alternative to Exim's own checking facilities for installations that are
9b371988
PH
1920already making use of &'tcpwrappers'& for other purposes. To do this, you
1921should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1922&_tcpd.h_& to be available at compile time, and also ensure that the library
1923&_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1924EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1925you might have
1926.code
1927USE_TCP_WRAPPERS=yes
1928CFLAGS=-O -I/usr/local/include
1929EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1930.endd
5dc43717
JJ
1931in &_Local/Makefile_&. The daemon name to use in the &'tcpwrappers'& control
1932files is &"exim"&. For example, the line
9b371988
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1933.code
1934exim : LOCAL 192.168.1. .friendly.domain.example
1935.endd
1936in your &_/etc/hosts.allow_& file allows connections from the local host, from
1937the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&.
5dc43717
JJ
1938All other connections are denied. The daemon name used by &'tcpwrappers'&
1939can be changed at build time by setting TCP_WRAPPERS_DAEMON_NAME in
1940in &_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the
1941configure file. Consult the &'tcpwrappers'& documentation for
168e428f 1942further details.
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1943
1944
f89d2485 1945.section "Including support for IPv6" "SECID28"
9b371988 1946.cindex "IPv6" "including support for"
168e428f 1947Exim contains code for use on systems that have IPv6 support. Setting
9b371988 1948&`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
168e428f
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1949it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1950where the IPv6 support is not fully integrated into the normal include and
1951library files.
1952
1953Two different types of DNS record for handling IPv6 addresses have been
f89d2485 1954defined. AAAA records (analogous to A records for IPv4) are in use, and are
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1955currently seen as the mainstream. Another record type called A6 was proposed
1956as better than AAAA because it had more flexibility. However, it was felt to be
9b371988 1957over-complex, and its status was reduced to &"experimental"&. It is not known
168e428f 1958if anyone is actually using A6 records. Exim has support for A6 records, but
9b371988 1959this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
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1960support has not been tested for some time.
1961
1962
1963
0a349494
PP
1964.section "Dynamically loaded lookup module support" "SECTdynamicmodules"
1965.cindex "lookup modules"
1966.cindex "dynamic modules"
1967.cindex ".so building"
1968On some platforms, Exim supports not compiling all lookup types directly into
1969the main binary, instead putting some into external modules which can be loaded
1970on demand.
1971This permits packagers to build Exim with support for lookups with extensive
1972library dependencies without requiring all users to install all of those
1973dependencies.
1974Most, but not all, lookup types can be built this way.
1975
1976Set &`LOOKUP_MODULE_DIR`& to the directory into which the modules will be
1977installed; Exim will only load modules from that directory, as a security
1978measure. You will need to set &`CFLAGS_DYNAMIC`& if not already defined
1979for your OS; see &_OS/Makefile-Linux_& for an example.
1980Some other requirements for adjusting &`EXTRALIBS`& may also be necessary,
1981see &_src/EDITME_& for details.
1982
1983Then, for each module to be loaded dynamically, define the relevant
1984&`LOOKUP_`&<&'lookup_type'&> flags to have the value "2" instead of "yes".
1985For example, this will build in lsearch but load sqlite and mysql support
1986on demand:
1987.code
1988LOOKUP_LSEARCH=yes
1989LOOKUP_SQLITE=2
1990LOOKUP_MYSQL=2
1991.endd
5d758a46 1992
0a349494 1993
f89d2485 1994.section "The building process" "SECID29"
9b371988
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1995.cindex "build directory"
1996Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
1997created, run &'make'& at the top level. It determines the architecture and
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1998operating system types, and creates a build directory if one does not exist.
1999For example, on a Sun system running Solaris 8, the directory
9b371988
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2000&_build-SunOS5-5.8-sparc_& is created.
2001.cindex "symbolic link" "to source files"
168e428f
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2002Symbolic links to relevant source files are installed in the build directory.
2003
9b371988 2004&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
168e428f
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2005building process fails if it is set.
2006
9b371988 2007If this is the first time &'make'& has been run, it calls a script that builds
168e428f 2008a make file inside the build directory, using the configuration files from the
9b371988
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2009&_Local_& directory. The new make file is then passed to another instance of
2010&'make'&. This does the real work, building a number of utility scripts, and
168e428f 2011then compiling and linking the binaries for the Exim monitor (if configured), a
9b371988
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2012number of utility programs, and finally Exim itself. The command &`make
2013makefile`& can be used to force a rebuild of the make file in the build
168e428f
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2014directory, should this ever be necessary.
2015
2016If you have problems building Exim, check for any comments there may be in the
9b371988 2017&_README_& file concerning your operating system, and also take a look at the
168e428f
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2018FAQ, where some common problems are covered.
2019
2020
2021
f89d2485 2022.section 'Output from &"make"&' "SECID283"
9b371988 2023The output produced by the &'make'& process for compile lines is often very
068aaea8
PH
2024unreadable, because these lines can be very long. For this reason, the normal
2025output is suppressed by default, and instead output similar to that which
2026appears when compiling the 2.6 Linux kernel is generated: just a short line for
2027each module that is being compiled or linked. However, it is still possible to
9b371988
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2028get the full output, by calling &'make'& like this:
2029.code
2030FULLECHO='' make -e
2031.endd
2032The value of FULLECHO defaults to &"@"&, the flag character that suppresses
2033command reflection in &'make'&. When you ask for the full output, it is
3cb1b51e 2034given in addition to the short output.
068aaea8
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2035
2036
2037
9b371988 2038.section "Overriding build-time options for Exim" "SECToverride"
f89d2485 2039.cindex "build-time options, overriding"
168e428f
PH
2040The main make file that is created at the beginning of the building process
2041consists of the concatenation of a number of files which set configuration
9b371988 2042values, followed by a fixed set of &'make'& instructions. If a value is set
168e428f
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2043more than once, the last setting overrides any previous ones. This provides a
2044convenient way of overriding defaults. The files that are concatenated are, in
2045order:
9b371988
PH
2046.display
2047&_OS/Makefile-Default_&
2048&_OS/Makefile-_&<&'ostype'&>
2049&_Local/Makefile_&
2050&_Local/Makefile-_&<&'ostype'&>
2051&_Local/Makefile-_&<&'archtype'&>
2052&_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
2053&_OS/Makefile-Base_&
2054.endd
2055.cindex "&_Local/Makefile_&"
2056.cindex "building Exim" "operating system type"
2057.cindex "building Exim" "architecture type"
2058where <&'ostype'&> is the operating system type and <&'archtype'&> is the
2059architecture type. &_Local/Makefile_& is required to exist, and the building
2060process fails if it is absent. The other three &_Local_& files are optional,
168e428f
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2061and are often not needed.
2062
9b371988
PH
2063The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
2064called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
168e428f
PH
2065the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
2066values are used, thereby providing a means of forcing particular settings.
9b371988 2067Otherwise, the scripts try to get values from the &%uname%& command. If this
168e428f 2068fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
9b371988 2069of &'ad hoc'& transformations are then applied, to produce the standard names
168e428f
PH
2070that Exim expects. You can run these scripts directly from the shell in order
2071to find out what values are being used on your system.
2072
2073
9b371988 2074&_OS/Makefile-Default_& contains comments about the variables that are set
168e428f
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2075therein. Some (but not all) are mentioned below. If there is something that
2076needs changing, review the contents of this file and the contents of the make
9b371988 2077file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
168e428f
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2078default values are.
2079
2080
9b371988
PH
2081.cindex "building Exim" "overriding default settings"
2082If you need to change any of the values that are set in &_OS/Makefile-Default_&
2083or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
168e428f 2084need to change the original files. Instead, you should make the changes by
9b371988
PH
2085putting the new values in an appropriate &_Local_& file. For example,
2086.cindex "Tru64-Unix build-time settings"
168e428f
PH
2087when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2088formerly DEC-OSF1) operating system, it is necessary to specify that the C
9b371988
PH
2089compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2090called with the option &%-std1%&, to make it recognize some of the features of
168e428f 2091Standard C that Exim uses. (Most other compilers recognize Standard C by
9b371988 2092default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
168e428f 2093containing the lines
9b371988
PH
2094.code
2095CC=cc
2096CFLAGS=-std1
2097.endd
168e428f 2098If you are compiling for just one operating system, it may be easier to put
9b371988 2099these lines directly into &_Local/Makefile_&.
168e428f
PH
2100
2101Keeping all your local configuration settings separate from the distributed
2102files makes it easy to transfer them to new versions of Exim simply by copying
9b371988 2103the contents of the &_Local_& directory.
168e428f
PH
2104
2105
9b371988
PH
2106.cindex "NIS lookup type" "including support for"
2107.cindex "NIS+ lookup type" "including support for"
2108.cindex "LDAP" "including support for"
2109.cindex "lookup" "inclusion in binary"
168e428f
PH
2110Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2111lookup, but not all systems have these components installed, so the default is
2112not to include the relevant code in the binary. All the different kinds of file
2113and database lookup that Exim supports are implemented as separate code modules
2114which are included only if the relevant compile-time options are set. In the
9b371988
PH
2115case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2116.code
2117LOOKUP_LDAP=yes
2118LOOKUP_NIS=yes
2119LOOKUP_NISPLUS=yes
2120.endd
168e428f 2121and similar settings apply to the other lookup types. They are all listed in
9b371988 2122&_src/EDITME_&. In many cases the relevant include files and interface
168e428f 2123libraries need to be installed before compiling Exim.
9b371988 2124.cindex "cdb" "including support for"
068aaea8
PH
2125However, there are some optional lookup types (such as cdb) for which
2126the code is entirely contained within Exim, and no external include
168e428f
PH
2127files or libraries are required. When a lookup type is not included in the
2128binary, attempts to configure Exim to use it cause run time configuration
2129errors.
2130
252e0c7b 2131.new
7e6a8985
PP
2132.cindex "pkg-config" "lookups"
2133.cindex "pkg-config" "authenticators"
252e0c7b
PP
2134Many systems now use a tool called &'pkg-config'& to encapsulate information
2135about how to compile against a library; Exim has some initial support for
2136being able to use pkg-config for lookups and authenticators. For any given
2137makefile variable which starts &`LOOKUP_`& or &`AUTH_`&, you can add a new
2138variable with the &`_PC`& suffix in the name and assign as the value the
2139name of the package to be queried. The results of querying via the
2140&'pkg-config'& command will be added to the appropriate Makefile variables
2141with &`+=`& directives, so your version of &'make'& will need to support that
2142syntax. For instance:
2143.code
2144LOOKUP_SQLITE=yes
2145LOOKUP_SQLITE_PC=sqlite3
2146AUTH_GSASL=yes
2147AUTH_GSASL_PC=libgsasl
2148AUTH_HEIMDAL_GSSAPI=yes
2149AUTH_HEIMDAL_GSSAPI_PC=heimdal-gssapi
2150.endd
2151.wen
2152
9b371988 2153.cindex "Perl" "including support for"
168e428f
PH
2154Exim can be linked with an embedded Perl interpreter, allowing Perl
2155subroutines to be called during string expansion. To enable this facility,
9b371988
PH
2156.code
2157EXIM_PERL=perl.o
2158.endd
2159must be defined in &_Local/Makefile_&. Details of this facility are given in
2160chapter &<<CHAPperl>>&.
168e428f 2161
f89d2485 2162.cindex "X11 libraries, location of"
168e428f 2163The location of the X11 libraries is something that varies a lot between
068aaea8 2164operating systems, and there may be different versions of X11 to cope
168e428f
PH
2165with. Exim itself makes no use of X11, but if you are compiling the Exim
2166monitor, the X11 libraries must be available.
9b371988
PH
2167The following three variables are set in &_OS/Makefile-Default_&:
2168.code
2169X11=/usr/X11R6
2170XINCLUDE=-I$(X11)/include
2171XLFLAGS=-L$(X11)/lib
2172.endd
168e428f 2173These are overridden in some of the operating-system configuration files. For
9b371988
PH
2174example, in &_OS/Makefile-SunOS5_& there is
2175.code
2176X11=/usr/openwin
2177XINCLUDE=-I$(X11)/include
2178XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2179.endd
168e428f
PH
2180If you need to override the default setting for your operating system, place a
2181definition of all three of these variables into your
9b371988 2182&_Local/Makefile-<ostype>_& file.
168e428f 2183
9b371988 2184.cindex "EXTRALIBS"
168e428f
PH
2185If you need to add any extra libraries to the link steps, these can be put in a
2186variable called EXTRALIBS, which appears in all the link commands, but by
2187default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2188command for linking the main Exim binary, and not for any associated utilities.
2189
9b371988 2190.cindex "DBM libraries" "configuration for building"
168e428f 2191There is also DBMLIB, which appears in the link commands for binaries that
9b371988 2192use DBM functions (see also section &<<SECTdb>>&). Finally, there is
168e428f
PH
2193EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2194binary, and which can be used, for example, to include additional X11
2195libraries.
2196
9b371988 2197.cindex "configuration file" "editing"
168e428f
PH
2198The make file copes with rebuilding Exim correctly if any of the configuration
2199files are edited. However, if an optional configuration file is deleted, it is
9b371988
PH
2200necessary to touch the associated non-optional file (that is,
2201&_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
168e428f
PH
2202
2203
f89d2485 2204.section "OS-specific header files" "SECID30"
9b371988
PH
2205.cindex "&_os.h_&"
2206.cindex "building Exim" "OS-specific C header files"
2207The &_OS_& directory contains a number of files with names of the form
2208&_os.h-<ostype>_&. These are system-specific C header files that should not
168e428f 2209normally need to be changed. There is a list of macro settings that are
9b371988 2210recognized in the file &_OS/os.configuring_&, which should be consulted if you
168e428f
PH
2211are porting Exim to a new operating system.
2212
2213
2214
f89d2485
PH
2215.section "Overriding build-time options for the monitor" "SECID31"
2216.cindex "building Eximon"
168e428f
PH
2217A similar process is used for overriding things when building the Exim monitor,
2218where the files that are involved are
9b371988
PH
2219.display
2220&_OS/eximon.conf-Default_&
2221&_OS/eximon.conf-_&<&'ostype'&>
2222&_Local/eximon.conf_&
2223&_Local/eximon.conf-_&<&'ostype'&>
2224&_Local/eximon.conf-_&<&'archtype'&>
2225&_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2226.endd
2227.cindex "&_Local/eximon.conf_&"
168e428f 2228As with Exim itself, the final three files need not exist, and in this case the
9b371988
PH
2229&_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2230&_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
168e428f
PH
2231variables of the same name, preceded by EXIMON_. For example, setting
2232EXIMON_LOG_DEPTH in the environment overrides the value of
2233LOG_DEPTH at run time.
4f578862 2234.ecindex IIDbuex
168e428f
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2235
2236
f89d2485 2237.section "Installing Exim binaries and scripts" "SECID32"
9b371988
PH
2238.cindex "installing Exim"
2239.cindex "BIN_DIRECTORY"
2240The command &`make install`& runs the &(exim_install)& script with no
2241arguments. The script copies binaries and utility scripts into the directory
2242whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2243.cindex "setuid" "installing Exim with"
068aaea8
PH
2244The install script copies files only if they are newer than the files they are
2245going to replace. The Exim binary is required to be owned by root and have the
9b371988
PH
2246&'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2247install`& as root so that it can set up the Exim binary in this way. However, in
068aaea8
PH
2248some special situations (for example, if a host is doing no local deliveries)
2249it may be possible to run Exim without making the binary setuid root (see
9b371988 2250chapter &<<CHAPsecurity>>& for details).
168e428f 2251
9b371988 2252.cindex "CONFIGURE_FILE"
168e428f 2253Exim's run time configuration file is named by the CONFIGURE_FILE setting
9b371988
PH
2254in &_Local/Makefile_&. If this names a single file, and the file does not
2255exist, the default configuration file &_src/configure.default_& is copied there
168e428f
PH
2256by the installation script. If a run time configuration file already exists, it
2257is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2258alternative files, no default is installed.
2259
9b371988
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2260.cindex "system aliases file"
2261.cindex "&_/etc/aliases_&"
168e428f
PH
2262One change is made to the default configuration file when it is installed: the
2263default configuration contains a router that references a system aliases file.
2264The path to this file is set to the value specified by
9b371988 2265SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
168e428f
PH
2266If the system aliases file does not exist, the installation script creates it,
2267and outputs a comment to the user.
2268
2269The created file contains no aliases, but it does contain comments about the
2270aliases a site should normally have. Mail aliases have traditionally been
9b371988
PH
2271kept in &_/etc/aliases_&. However, some operating systems are now using
2272&_/etc/mail/aliases_&. You should check if yours is one of these, and change
168e428f
PH
2273Exim's configuration if necessary.
2274
2275The default configuration uses the local host's name as the only local domain,
9b371988
PH
2276and is set up to do local deliveries into the shared directory &_/var/mail_&,
2277running as the local user. System aliases and &_.forward_& files in users' home
168e428f
PH
2278directories are supported, but no NIS or NIS+ support is configured. Domains
2279other than the name of the local host are routed using the DNS, with delivery
2280over SMTP.
2281
168e428f
PH
2282It is possible to install Exim for special purposes (such as building a binary
2283distribution) in a private part of the file system. You can do this by a
2284command such as
9b371988
PH
2285.code
2286make DESTDIR=/some/directory/ install
2287.endd
168e428f
PH
2288This has the effect of pre-pending the specified directory to all the file
2289paths, except the name of the system aliases file that appears in the default
9b371988 2290configuration. (If a default alias file is created, its name &'is'& modified.)
168e428f
PH
2291For backwards compatibility, ROOT is used if DESTDIR is not set,
2292but this usage is deprecated.
2293
9b371988
PH
2294.cindex "installing Exim" "what is not installed"
2295Running &'make install'& does not copy the Exim 4 conversion script
40df1be3
TF
2296&'convert4r4'&. You will probably run this only once if you are
2297upgrading from Exim 3. None of the documentation files in the &_doc_&
168e428f 2298directory are copied, except for the info files when you have set
9b371988 2299INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
168e428f 2300
9b371988 2301For the utility programs, old versions are renamed by adding the suffix &_.O_&
168e428f
PH
2302to their names. The Exim binary itself, however, is handled differently. It is
2303installed under a name that includes the version number and the compile number,
9b371988
PH
2304for example &_exim-&version;-1_&. The script then arranges for a symbolic link
2305called &_exim_& to point to the binary. If you are updating a previous version
2306of Exim, the script takes care to ensure that the name &_exim_& is never absent
168e428f
PH
2307from the directory (as seen by other processes).
2308
9b371988
PH
2309.cindex "installing Exim" "testing the script"
2310If you want to see what the &'make install'& will do before running it for
2311real, you can pass the &%-n%& option to the installation script by this
2312command:
2313.code
2314make INSTALL_ARG=-n install
2315.endd
168e428f
PH
2316The contents of the variable INSTALL_ARG are passed to the installation
2317script. You do not need to be root to run this test. Alternatively, you can run
2318the installation script directly, but this must be from within the build
2319directory. For example, from the top-level Exim directory you could use this
2320command:
9b371988
PH
2321.code
2322(cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2323.endd
2324.cindex "installing Exim" "install script options"
168e428f
PH
2325There are two other options that can be supplied to the installation script.
2326
9b371988
PH
2327.ilist
2328&%-no_chown%& bypasses the call to change the owner of the installed binary
168e428f 2329to root, and the call to make it a setuid binary.
9b371988
PH
2330.next
2331&%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
168e428f 2332installed binary.
9b371988 2333.endlist
168e428f
PH
2334
2335INSTALL_ARG can be used to pass these options to the script. For example:
9b371988
PH
2336.code
2337make INSTALL_ARG=-no_symlink install
2338.endd
168e428f
PH
2339The installation script can also be given arguments specifying which files are
2340to be copied. For example, to install just the Exim binary, and nothing else,
2341without creating the symbolic link, you could use:
9b371988
PH
2342.code
2343make INSTALL_ARG='-no_symlink exim' install
2344.endd
168e428f
PH
2345
2346
2347
9b371988
PH
2348.section "Installing info documentation" "SECTinsinfdoc"
2349.cindex "installing Exim" "&'info'& documentation"
2350Not all systems use the GNU &'info'& system for documentation, and for this
168e428f
PH
2351reason, the Texinfo source of Exim's documentation is not included in the main
2352distribution. Instead it is available separately from the ftp site (see section
9b371988 2353&<<SECTavail>>&).
168e428f 2354
9b371988
PH
2355If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2356source of the documentation is found in the source tree, running &`make
2357install`& automatically builds the info files and installs them.
168e428f
PH
2358
2359
2360
f89d2485 2361.section "Setting up the spool directory" "SECID33"
9b371988 2362.cindex "spool directory" "creating"
168e428f
PH
2363When it starts up, Exim tries to create its spool directory if it does not
2364exist. The Exim uid and gid are used for the owner and group of the spool
2365directory. Sub-directories are automatically created in the spool directory as
2366necessary.
2367
2368
2369
2370
f89d2485 2371.section "Testing" "SECID34"
9b371988 2372.cindex "testing" "installation"
168e428f
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2373Having installed Exim, you can check that the run time configuration file is
2374syntactically valid by running the following command, which assumes that the
2375Exim binary directory is within your PATH environment variable:
9b371988
PH
2376.code
2377exim -bV
2378.endd
168e428f
PH
2379If there are any errors in the configuration file, Exim outputs error messages.
2380Otherwise it outputs the version number and build date,
2381the DBM library that is being used, and information about which drivers and
2382other optional code modules are included in the binary.
2383Some simple routing tests can be done by using the address testing option. For
2384example,
9b371988
PH
2385.display
2386&`exim -bt`& <&'local username'&>
2387.endd
168e428f 2388should verify that it recognizes a local mailbox, and
9b371988
PH
2389.display
2390&`exim -bt`& <&'remote address'&>
2391.endd
168e428f
PH
2392a remote one. Then try getting it to deliver mail, both locally and remotely.
2393This can be done by passing messages directly to Exim, without going through a
2394user agent. For example:
9b371988 2395.code
068aaea8
PH
2396exim -v postmaster@your.domain.example
2397From: user@your.domain.example
2398To: postmaster@your.domain.example
2399Subject: Testing Exim
168e428f 2400
068aaea8
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2401This is a test message.
2402^D
9b371988
PH
2403.endd
2404The &%-v%& option causes Exim to output some verification of what it is doing.
168e428f 2405In this case you should see copies of three log lines, one for the message's
9b371988 2406arrival, one for its delivery, and one containing &"Completed"&.
168e428f 2407
9b371988
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2408.cindex "delivery" "problems with"
2409If you encounter problems, look at Exim's log files (&'mainlog'& and
2410&'paniclog'&) to see if there is any relevant information there. Another source
168e428f 2411of information is running Exim with debugging turned on, by specifying the
9b371988 2412&%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
168e428f 2413with debugging turned on by a command of the form
9b371988
PH
2414.display
2415&`exim -d -M`& <&'exim-message-id'&>
2416.endd
2417You must be root or an &"admin user"& in order to do this. The &%-d%& option
168e428f 2418produces rather a lot of output, but you can cut this down to specific areas.
9b371988
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2419For example, if you use &%-d-all+route%& only the debugging information
2420relevant to routing is included. (See the &%-d%& option in chapter
2421&<<CHAPcommandline>>& for more details.)
168e428f 2422
9b371988
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2423.cindex '&"sticky"& bit'
2424.cindex "lock files"
168e428f
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2425One specific problem that has shown up on some sites is the inability to do
2426local deliveries into a shared mailbox directory, because it does not have the
9b371988 2427&"sticky bit"& set on it. By default, Exim tries to create a lock file before
168e428f 2428writing to a mailbox file, and if it cannot create the lock file, the delivery
9b371988 2429is deferred. You can get round this either by setting the &"sticky bit"& on the
168e428f
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2430directory, or by setting a specific group for local deliveries and allowing
2431that group to create files in the directory (see the comments above the
9b371988 2432&(local_delivery)& transport in the default configuration file). Another
168e428f 2433approach is to configure Exim not to use lock files, but just to rely on
9b371988
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2434&[fcntl()]& locking instead. However, you should do this only if all user
2435agents also use &[fcntl()]& locking. For further discussion of locking issues,
2436see chapter &<<CHAPappendfile>>&.
168e428f
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2437
2438One thing that cannot be tested on a system that is already running an MTA is
2439the receipt of incoming SMTP mail on the standard SMTP port. However, the
9b371988
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2440&%-oX%& option can be used to run an Exim daemon that listens on some other
2441port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2442&'exim_checkaccess'& utility can be used to check out policy controls on
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2443incoming SMTP mail.
2444
2445Testing a new version on a system that is already running Exim can most easily
2446be done by building a binary with a different CONFIGURE_FILE setting. From
2447within the run time configuration, all other file and directory names
2448that Exim uses can be altered, in order to keep it entirely clear of the
2449production version.
2450
2451
f89d2485 2452.section "Replacing another MTA with Exim" "SECID35"
9b371988 2453.cindex "replacing another MTA"
168e428f
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2454Building and installing Exim for the first time does not of itself put it in
2455general use. The name by which the system's MTA is called by mail user agents
9b371988
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2456is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2457operating system), and it is necessary to make this name point to the &'exim'&
168e428f 2458binary in order to get the user agents to pass messages to Exim. This is
9b371988
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2459normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2460or &_/usr/lib/sendmail_&
2461.cindex "symbolic link" "to &'exim'& binary"
2462a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
168e428f
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2463privilege and executable status from the old MTA. It is then necessary to stop
2464and restart the mailer daemon, if one is running.
2465
f89d2485 2466.cindex "FreeBSD, MTA indirection"
9b371988 2467.cindex "&_/etc/mail/mailer.conf_&"
168e428f
PH
2468Some operating systems have introduced alternative ways of switching MTAs. For
2469example, if you are running FreeBSD, you need to edit the file
9b371988 2470&_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
168e428f
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2471described. A typical example of the contents of this file for running Exim is
2472as follows:
9b371988
PH
2473.code
2474sendmail /usr/exim/bin/exim
2475send-mail /usr/exim/bin/exim
2476mailq /usr/exim/bin/exim -bp
2477newaliases /usr/bin/true
2478.endd
2479Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2480your Exim installation is &"live"&. Check it by sending a message from your
168e428f
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2481favourite user agent.
2482
2483You should consider what to tell your users about the change of MTA. Exim may
2484have different capabilities to what was previously running, and there are
2485various operational differences such as the text of messages produced by
2486command line options and in bounce messages. If you allow your users to make
2487use of Exim's filtering capabilities, you should make the document entitled
9b371988 2488&'Exim's interface to mail filtering'& available to them.
168e428f
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2489
2490
2491
f89d2485 2492.section "Upgrading Exim" "SECID36"
9b371988 2493.cindex "upgrading Exim"
168e428f
PH
2494If you are already running Exim on your host, building and installing a new
2495version automatically makes it available to MUAs, or any other programs that
2496call the MTA directly. However, if you are running an Exim daemon, you do need
9b371988
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2497to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2498new binary. You do not need to stop processing mail in order to install a new
068aaea8
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2499version of Exim. The install script does not modify an existing runtime
2500configuration file.
2501
168e428f
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2502
2503
2504
f89d2485 2505.section "Stopping the Exim daemon on Solaris" "SECID37"
9b371988 2506.cindex "Solaris" "stopping Exim on"
168e428f 2507The standard command for stopping the mailer daemon on Solaris is
9b371988
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2508.code
2509/etc/init.d/sendmail stop
2510.endd
2511If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2512fails to stop Exim because it uses the command &'ps -e'& and greps the output
2513for the text &"sendmail"&; this is not present because the actual program name
2514(that is, &"exim"&) is given by the &'ps'& command with these options. A
2515solution is to replace the line that finds the process id with something like
2516.code
2517pid=`cat /var/spool/exim/exim-daemon.pid`
2518.endd
168e428f
PH
2519to obtain the daemon's pid directly from the file that Exim saves it in.
2520
9b371988 2521Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
168e428f
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2522still be received from local processes, and if automatic delivery is configured
2523(the normal case), deliveries will still occur.
2524
2525
2526
2527
9b371988
PH
2528. ////////////////////////////////////////////////////////////////////////////
2529. ////////////////////////////////////////////////////////////////////////////
168e428f 2530
9b371988 2531.chapter "The Exim command line" "CHAPcommandline"
4f578862
PH
2532.scindex IIDclo1 "command line" "options"
2533.scindex IIDclo2 "options" "command line"
168e428f
PH
2534Exim's command line takes the standard Unix form of a sequence of options,
2535each starting with a hyphen character, followed by a number of arguments. The
2536options are compatible with the main options of Sendmail, and there are also
2537some additional options, some of which are compatible with Smail 3. Certain
2538combinations of options do not make sense, and provoke an error if used.
2539The form of the arguments depends on which options are set.
2540
2541
f89d2485 2542.section "Setting options by program name" "SECID38"
9b371988
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2543.cindex "&'mailq'&"
2544If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
168e428f 2545were present before any other options.
9b371988 2546The &%-bp%& option requests a listing of the contents of the mail queue on the
168e428f
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2547standard output.
2548This feature is for compatibility with some systems that contain a command of
2549that name in one of the standard libraries, symbolically linked to
9b371988
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2550&_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2551
2552.cindex "&'rsmtp'&"
2553If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2554were present before any other options, for compatibility with Smail. The
2555&%-bS%& option is used for reading in a number of messages in batched SMTP
2556format.
2557
2558.cindex "&'rmail'&"
2559If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2560&%-oee%& options were present before any other options, for compatibility with
2561Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2562
2563.cindex "&'runq'&"
2564.cindex "queue runner"
2565If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2566were present before any other options, for compatibility with Smail. The &%-q%&
168e428f
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2567option causes a single queue runner process to be started.
2568
9b371988
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2569.cindex "&'newaliases'&"
2570.cindex "alias file" "building"
2571.cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2572If Exim is called under the name &'newaliases'& it behaves as if the option
2573&%-bi%& were present before any other options, for compatibility with Sendmail.
168e428f
PH
2574This option is used for rebuilding Sendmail's alias file. Exim does not have
2575the concept of a single alias file, but can be configured to run a given
9b371988 2576command if called with the &%-bi%& option.
168e428f
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2577
2578
9b371988
PH
2579.section "Trusted and admin users" "SECTtrustedadmin"
2580Some Exim options are available only to &'trusted users'& and others are
2581available only to &'admin users'&. In the description below, the phrases &"Exim
2582user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2583EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2584&%exim_group%& options. These do not necessarily have to use the name &"exim"&.
168e428f 2585
9b371988 2586.ilist
f89d2485 2587.cindex "trusted users" "definition of"
9b371988 2588.cindex "user" "trusted definition of"
168e428f 2589The trusted users are root, the Exim user, any user listed in the
9b371988
PH
2590&%trusted_users%& configuration option, and any user whose current group or any
2591supplementary group is one of those listed in the &%trusted_groups%&
168e428f 2592configuration option. Note that the Exim group is not automatically trusted.
9b371988
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2593
2594.cindex '&"From"& line'
2595.cindex "envelope sender"
2596Trusted users are always permitted to use the &%-f%& option or a leading
2597&"From&~"& line to specify the envelope sender of a message that is passed to
2598Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2599See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2600users to set envelope senders.
2601
2602.cindex "&'From:'& header line"
2603.cindex "&'Sender:'& header line"
2604For a trusted user, there is never any check on the contents of the &'From:'&
2605header line, and a &'Sender:'& line is never added. Furthermore, any existing
2606&'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2607
168e428f
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2608Trusted users may also specify a host name, host address, interface address,
2609protocol name, ident value, and authentication data when submitting a message
2610locally. Thus, they are able to insert messages into Exim's queue locally that
2611have the characteristics of messages received from a remote host. Untrusted
9b371988 2612users may in some circumstances use &%-f%&, but can never set the other values
168e428f 2613that are available to trusted users.
9b371988
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2614.next
2615.cindex "user" "admin definition of"
2616.cindex "admin user" "definition of"
168e428f 2617The admin users are root, the Exim user, and any user that is a member of the
9b371988 2618Exim group or of any group listed in the &%admin_groups%& configuration option.
168e428f 2619The current group does not have to be one of these groups.
9b371988 2620
168e428f
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2621Admin users are permitted to list the queue, and to carry out certain
2622operations on messages, for example, to force delivery failures. It is also
2623necessary to be an admin user in order to see the full information provided by
2624the Exim monitor, and full debugging output.
9b371988
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2625
2626By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2627Exim to attempt delivery of messages on its queue is restricted to admin users.
2628However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2629option false (that is, specifying &%no_prod_requires_admin%&).
2630
2631Similarly, the use of the &%-bp%& option to list all the messages in the queue
2632is restricted to admin users unless &%queue_list_requires_admin%& is set
168e428f 2633false.
9b371988 2634.endlist
168e428f
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2635
2636
9b371988 2637&*Warning*&: If you configure your system so that admin users are able to
168e428f
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2638edit Exim's configuration file, you are giving those users an easy way of
2639getting root. There is further discussion of this issue at the start of chapter
9b371988 2640&<<CHAPconf>>&.
168e428f
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2641
2642
2643
2644
f89d2485 2645.section "Command line options" "SECID39"
db9452a9
PH
2646Exim's command line options are described in alphabetical order below. If none
2647of the options that specifies a specific action (such as starting the daemon or
2648a queue runner, or testing an address, or receiving a message in a specific
2649format, or listing the queue) are present, and there is at least one argument
2650on the command line, &%-bm%& (accept a local message on the standard input,
2651with the arguments specifying the recipients) is assumed. Otherwise, Exim
2652outputs a brief message about itself and exits.
168e428f 2653
9b371988
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2654. ////////////////////////////////////////////////////////////////////////////
2655. Insert a stylized XML comment here, to identify the start of the command line
2656. options. This is for the benefit of the Perl script that automatically
2657. creates a man page for the options.
2658. ////////////////////////////////////////////////////////////////////////////
168e428f 2659
9b371988 2660.literal xml
168e428f 2661<!-- === Start of command line options === -->
9b371988 2662.literal off
168e428f
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2663
2664
9b371988
PH
2665.vlist
2666.vitem &%--%&
2667.oindex "--"
2668.cindex "options" "command line; terminating"
168e428f
PH
2669This is a pseudo-option whose only purpose is to terminate the options and
2670therefore to cause subsequent command line items to be treated as arguments
2671rather than options, even if they begin with hyphens.
2672
9b371988
PH
2673.vitem &%--help%&
2674.oindex "&%--help%&"
168e428f
PH
2675This option causes Exim to output a few sentences stating what it is.
2676The same output is generated if the Exim binary is called with no options and
2677no arguments.
2678
4b2241d2
PP
2679.vitem &%--version%&
2680.oindex "&%--version%&"
2681This option is an alias for &%-bV%& and causes version information to be
2682displayed.
2683
9b371988
PH
2684.vitem &%-B%&<&'type'&>
2685.oindex "&%-B%&"
2686.cindex "8-bit characters"
2687.cindex "Sendmail compatibility" "8-bit characters"
168e428f
PH
2688This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2689clean; it ignores this option.
2690
9b371988
PH
2691.vitem &%-bd%&
2692.oindex "&%-bd%&"
2693.cindex "daemon"
f89d2485 2694.cindex "SMTP" "listener"
9b371988 2695.cindex "queue runner"
168e428f 2696This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
9b371988
PH
2697the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2698that the daemon should also initiate periodic queue runs.
2699
2700The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2701(debugging) or &%-v%& (verifying) options are set, the daemon does not
168e428f
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2702disconnect from the controlling terminal. When running this way, it can be
2703stopped by pressing ctrl-C.
9b371988 2704
168e428f
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2705By default, Exim listens for incoming connections to the standard SMTP port on
2706all the host's running interfaces. However, it is possible to listen on other
2707ports, on multiple ports, and only on specific interfaces. Chapter
9b371988
PH
2708&<<CHAPinterfaces>>& contains a description of the options that control this.
2709
168e428f 2710When a listening daemon
9b371988
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2711.cindex "daemon" "process id (pid)"
2712.cindex "pid (process id)" "of daemon"
2713is started without the use of &%-oX%& (that is, without overriding the normal
2714configuration), it writes its process id to a file called &_exim-daemon.pid_&
2715in Exim's spool directory. This location can be overridden by setting
2716PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
168e428f 2717running as root.
9b371988
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2718
2719When &%-oX%& is used on the command line to start a listening daemon, the
2720process id is not written to the normal pid file path. However, &%-oP%& can be
168e428f 2721used to specify a path on the command line if a pid file is required.
9b371988 2722
168e428f 2723The SIGHUP signal
9b371988 2724.cindex "SIGHUP"
3cb1b51e
PH
2725.cindex "daemon" "restarting"
2726can be used to cause the daemon to re-execute itself. This should be done
2727whenever Exim's configuration file, or any file that is incorporated into it by
2728means of the &%.include%& facility, is changed, and also whenever a new version
2729of Exim is installed. It is not necessary to do this when other files that are
9b371988
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2730referenced from the configuration (for example, alias files) are changed,
2731because these are reread each time they are used.
2732
2733.vitem &%-bdf%&
2734.oindex "&%-bdf%&"
2735This option has the same effect as &%-bd%& except that it never disconnects
2736from the controlling terminal, even when no debugging is specified.
2737
2738.vitem &%-be%&
2739.oindex "&%-be%&"
2740.cindex "testing" "string expansion"
2741.cindex "expansion" "testing"
168e428f
PH
2742Run Exim in expansion testing mode. Exim discards its root privilege, to
2743prevent ordinary users from using this mode to read otherwise inaccessible
2744files. If no arguments are given, Exim runs interactively, prompting for lines
4f578862 2745of data. Otherwise, it processes each argument in turn.
9b371988
PH
2746
2747If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2748to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2749used without command line arguments. If successful, it uses the &[readline()]&
168e428f
PH
2750function, which provides extensive line-editing facilities, for reading the
2751test data. A line history is supported.
9b371988 2752
168e428f 2753Long expansion expressions can be split over several lines by using backslash
068aaea8 2754continuations. As in Exim's run time configuration, white space at the start of
168e428f
PH
2755continuation lines is ignored. Each argument or data line is passed through the
2756string expansion mechanism, and the result is output. Variable values from the
9b371988 2757configuration file (for example, &$qualify_domain$&) are available, but no
3cb1b51e 2758message-specific values (such as &$sender_domain$&) are set, because no message
f89d2485 2759is being processed (but see &%-bem%& and &%-Mset%&).
168e428f 2760
9b371988
PH
2761&*Note*&: If you use this mechanism to test lookups, and you change the data
2762files or databases you are using, you must exit and restart Exim before trying
2763the same lookup again. Otherwise, because each Exim process caches the results
2764of lookups, you will just get the same result as before.
9b371988 2765
3cb1b51e
PH
2766.vitem &%-bem%&&~<&'filename'&>
2767.oindex "&%-bem%&"
2768.cindex "testing" "string expansion"
2769.cindex "expansion" "testing"
2770This option operates like &%-be%& except that it must be followed by the name
2771of a file. For example:
2772.code
2773exim -bem /tmp/testmessage
2774.endd
2775The file is read as a message (as if receiving a locally-submitted non-SMTP
2776message) before any of the test expansions are done. Thus, message-specific
2777variables such as &$message_size$& and &$header_from:$& are available. However,
2778no &'Received:'& header is added to the message. If the &%-t%& option is set,
2779recipients are read from the headers in the normal way, and are shown in the
2780&$recipients$& variable. Note that recipients cannot be given on the command
2781line, because further arguments are taken as strings to expand (just like
2782&%-be%&).
3cb1b51e 2783
9b371988
PH
2784.vitem &%-bF%&&~<&'filename'&>
2785.oindex "&%-bF%&"
2786.cindex "system filter" "testing"
2787.cindex "testing" "system filter"
2788This option is the same as &%-bf%& except that it assumes that the filter being
168e428f
PH
2789tested is a system filter. The additional commands that are available only in
2790system filters are recognized.
2791
9b371988
PH
2792.vitem &%-bf%&&~<&'filename'&>
2793.oindex "&%-bf%&"
2794.cindex "filter" "testing"
2795.cindex "testing" "filter file"
2796.cindex "forward file" "testing"
2797.cindex "testing" "forward file"
2798.cindex "Sieve filter" "testing"
168e428f
PH
2799This option runs Exim in user filter testing mode; the file is the filter file
2800to be tested, and a test message must be supplied on the standard input. If
2801there are no message-dependent tests in the filter, an empty file can be
2802supplied.
168e428f 2803
9b371988
PH
2804If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2805can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2806filter and a user filter in the same run. For example:
2807.code
2808exim -bF /system/filter -bf /user/filter </test/message
2809.endd
168e428f
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2810This is helpful when the system filter adds header lines or sets filter
2811variables that are used by the user filter.
168e428f 2812
9b371988
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2813If the test filter file does not begin with one of the special lines
2814.code
2815# Exim filter
2816# Sieve filter
2817.endd
2818it is taken to be a normal &_.forward_& file, and is tested for validity under
2819that interpretation. See sections &<<SECTitenonfilred>>& to
2820&<<SECTspecitredli>>& for a description of the possible contents of non-filter
2821redirection lists.
2822
2823The result of an Exim command that uses &%-bf%&, provided no errors are
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2824detected, is a list of the actions that Exim would try to take if presented
2825with the message for real. More details of filter testing are given in the
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2826separate document entitled &'Exim's interfaces to mail filtering'&.
2827
168e428f 2828When testing a filter file,
9b371988
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2829.cindex "&""From""& line"
2830.cindex "envelope sender"
f89d2485 2831.oindex "&%-f%&" "for filter testing"
9b371988
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2832the envelope sender can be set by the &%-f%& option,
2833or by a &"From&~"& line at the start of the test message. Various parameters
2834that would normally be taken from the envelope recipient address of the message
2835can be set by means of additional command line options (see the next four
2836options).
2837
2838.vitem &%-bfd%&&~<&'domain'&>
2839.oindex "&%-bfd%&"
f89d2485 2840.vindex "&$qualify_domain$&"
168e428f 2841This sets the domain of the recipient address when a filter file is being
9b371988
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2842tested by means of the &%-bf%& option. The default is the value of
2843&$qualify_domain$&.
168e428f 2844
9b371988
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2845.vitem &%-bfl%&&~<&'local&~part'&>
2846.oindex "&%-bfl%&"
168e428f 2847This sets the local part of the recipient address when a filter file is being
9b371988 2848tested by means of the &%-bf%& option. The default is the username of the
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2849process that calls Exim. A local part should be specified with any prefix or
2850suffix stripped, because that is how it appears to the filter when a message is
2851actually being delivered.
2852
9b371988
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2853.vitem &%-bfp%&&~<&'prefix'&>
2854.oindex "&%-bfp%&"
168e428f 2855This sets the prefix of the local part of the recipient address when a filter
9b371988 2856file is being tested by means of the &%-bf%& option. The default is an empty
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2857prefix.
2858
9b371988
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2859.vitem &%-bfs%&&~<&'suffix'&>
2860.oindex "&%-bfs%&"
168e428f 2861This sets the suffix of the local part of the recipient address when a filter
9b371988 2862file is being tested by means of the &%-bf%& option. The default is an empty
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2863suffix.
2864
9b371988
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2865.vitem &%-bh%&&~<&'IP&~address'&>
2866.oindex "&%-bh%&"
2867.cindex "testing" "incoming SMTP"
2868.cindex "SMTP" "testing incoming"
2869.cindex "testing" "relay control"
2870.cindex "relaying" "testing configuration"
2871.cindex "policy control" "testing"
2872.cindex "debugging" "&%-bh%& option"
168e428f
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2873This option runs a fake SMTP session as if from the given IP address, using the
2874standard input and output. The IP address may include a port number at the end,
2875after a full stop. For example:
9b371988
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2876.code
2877exim -bh 10.9.8.7.1234
2878exim -bh fe80::a00:20ff:fe86:a061.5678
2879.endd
168e428f 2880When an IPv6 address is given, it is converted into canonical form. In the case
9b371988
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2881of the second example above, the value of &$sender_host_address$& after
2882conversion to the canonical form is
2883&`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2884
168e428f 2885Comments as to what is going on are written to the standard error file. These
9b371988 2886include lines beginning with &"LOG"& for anything that would have been logged.
168e428f
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2887This facility is provided for testing configuration options for incoming
2888messages, to make sure they implement the required policy. For example, you can
9b371988
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2889test your relay controls using &%-bh%&.
2890
2891&*Warning 1*&:
2892.cindex "RFC 1413"
db9452a9
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2893You can test features of the configuration that rely on ident (RFC 1413)
2894information by using the &%-oMt%& option. However, Exim cannot actually perform
2895an ident callout when testing using &%-bh%& because there is no incoming SMTP
2896connection.
9b371988
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2897
2898&*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2899are also skipped when testing using &%-bh%&. If you want these callouts to
2900occur, use &%-bhc%& instead.
2901
168e428f
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2902Messages supplied during the testing session are discarded, and nothing is
2903written to any of the real log files. There may be pauses when DNS (and other)
9b371988 2904lookups are taking place, and of course these may time out. The &%-oMi%& option
db9452a9
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2905can be used to specify a specific IP interface and port if this is important,
2906and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2907session were authenticated.
9b371988
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2908
2909The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
168e428f 2910output just states whether a given recipient address from a given host is
9b371988 2911acceptable or not. See section &<<SECTcheckaccess>>&.
168e428f 2912
3cb1b51e 2913Features such as authentication and encryption, where the client input is not
f89d2485
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2914plain text, cannot easily be tested with &%-bh%&. Instead, you should use a
2915specialized SMTP test program such as
3cb1b51e 2916&url(http://jetmore.org/john/code/#swaks,swaks).
3cb1b51e 2917
9b371988
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2918.vitem &%-bhc%&&~<&'IP&~address'&>
2919.oindex "&%-bhc%&"
2920This option operates in the same way as &%-bh%&, except that address
168e428f
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2921verification callouts are performed if required. This includes consulting and
2922updating the callout cache database.
2923
9b371988
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2924.vitem &%-bi%&
2925.oindex "&%-bi%&"
2926.cindex "alias file" "building"
2927.cindex "building alias file"
2928.cindex "Sendmail compatibility" "&%-bi%& option"
2929Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
168e428f 2930Exim does not have the concept of a single alias file, and so it cannot mimic
9b371988 2931this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
168e428f
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2932tend to appear in various scripts such as NIS make files, so the option must be
2933recognized.
9b371988
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2934
2935If &%-bi%& is encountered, the command specified by the &%bi_command%&
168e428f 2936configuration option is run, under the uid and gid of the caller of Exim. If
9b371988
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2937the &%-oA%& option is used, its value is passed to the command as an argument.
2938The command set by &%bi_command%& may not contain arguments. The command can
2939use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2940if this is required. If the &%bi_command%& option is not set, calling Exim with
2941&%-bi%& is a no-op.
2942
2943.vitem &%-bm%&
2944.oindex "&%-bm%&"
2945.cindex "local message reception"
168e428f
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2946This option runs an Exim receiving process that accepts an incoming,
2947locally-generated message on the current input. The recipients are given as the
9b371988 2948command arguments (except when &%-t%& is also present &-- see below). Each
168e428f
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2949argument can be a comma-separated list of RFC 2822 addresses. This is the
2950default option for selecting the overall action of an Exim call; it is assumed
2951if no other conflicting option is present.
9b371988 2952
168e428f 2953If any addresses in the message are unqualified (have no domain), they are
9b371988
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2954qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
2955options, as appropriate. The &%-bnq%& option (see below) provides a way of
168e428f 2956suppressing this for special cases.
9b371988 2957
168e428f 2958Policy checks on the contents of local messages can be enforced by means of
9b371988
PH
2959the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
2960
2961.cindex "return code" "for &%-bm%&"
2962The return code is zero if the message is successfully accepted. Otherwise, the
2963action is controlled by the &%-oe%&&'x'& option setting &-- see below.
2964
168e428f 2965The format
9b371988
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2966.cindex "message" "format"
2967.cindex "format" "message"
2968.cindex "&""From""& line"
2969.cindex "UUCP" "&""From""& line"
2970.cindex "Sendmail compatibility" "&""From""& line"
168e428f
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2971of the message must be as defined in RFC 2822, except that, for
2972compatibility with Sendmail and Smail, a line in one of the forms
9b371988
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2973.code
2974From sender Fri Jan 5 12:55 GMT 1997
2975From sender Fri, 5 Jan 97 12:55:01
2976.endd
168e428f
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2977(with the weekday optional, and possibly with additional text after the date)
2978is permitted to appear at the start of the message. There appears to be no
2979authoritative specification of the format of this line. Exim recognizes it by
9b371988 2980matching against the regular expression defined by the &%uucp_from_pattern%&
168e428f 2981option, which can be changed if necessary.
9b371988 2982
f89d2485
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2983.oindex "&%-f%&" "overriding &""From""& line"
2984The specified sender is treated as if it were given as the argument to the
9b371988 2985&%-f%& option, but if a &%-f%& option is also present, its argument is used in
168e428f
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2986preference to the address taken from the message. The caller of Exim must be a
2987trusted user for the sender of a message to be set in this way.
2988
9b371988
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2989.vitem &%-bnq%&
2990.oindex "&%-bnq%&"
f89d2485 2991.cindex "address qualification, suppressing"
168e428f
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2992By default, Exim automatically qualifies unqualified addresses (those
2993without domains) that appear in messages that are submitted locally (that
2994is, not over TCP/IP). This qualification applies both to addresses in
2995envelopes, and addresses in header lines. Sender addresses are qualified using
9b371988
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2996&%qualify_domain%&, and recipient addresses using &%qualify_recipient%& (which
2997defaults to the value of &%qualify_domain%&).
2998
2999Sometimes, qualification is not wanted. For example, if &%-bS%& (batch SMTP) is
168e428f
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3000being used to re-submit messages that originally came from remote hosts after
3001content scanning, you probably do not want to qualify unqualified addresses in
3002header lines. (Such lines will be present only if you have not enabled a header
3003syntax check in the appropriate ACL.)
9b371988
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3004
3005The &%-bnq%& option suppresses all qualification of unqualified addresses in
168e428f
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3006messages that originate on the local host. When this is used, unqualified
3007addresses in the envelope provoke errors (causing message rejection) and
3008unqualified addresses in header lines are left alone.
3009
3010
9b371988
PH
3011.vitem &%-bP%&
3012.oindex "&%-bP%&"
595028e4 3013.cindex "configuration options" "extracting"
9b371988 3014.cindex "options" "configuration &-- extracting"
168e428f
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3015If this option is given with no arguments, it causes the values of all Exim's
3016main configuration options to be written to the standard output. The values
3017of one or more specific options can be requested by giving their names as
3018arguments, for example:
9b371988
PH
3019.code
3020exim -bP qualify_domain hold_domains
3021.endd
595028e4
PH
3022.cindex "hiding configuration option values"
3023.cindex "configuration options" "hiding value of"
3024.cindex "options" "hiding value of"
9b371988 3025However, any option setting that is preceded by the word &"hide"& in the
168e428f
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3026configuration file is not shown in full, except to an admin user. For other
3027users, the output is as in this example:
9b371988
PH
3028.code
3029mysql_servers = <value not displayable>
3030.endd
3031If &%configure_file%& is given as an argument, the name of the run time
168e428f
PH
3032configuration file is output.
3033If a list of configuration files was supplied, the value that is output here
3034is the name of the file that was actually used.
168e428f 3035
9b371988
PH
3036.cindex "daemon" "process id (pid)"
3037.cindex "pid (process id)" "of daemon"
3038If &%log_file_path%& or &%pid_file_path%& are given, the names of the
3039directories where log files and daemon pid files are written are output,
3040respectively. If these values are unset, log files are written in a
3041sub-directory of the spool directory called &%log%&, and the pid file is
3042written directly into the spool directory.
3043
3044If &%-bP%& is followed by a name preceded by &`+`&, for example,
3045.code
3046exim -bP +local_domains
3047.endd
168e428f
PH
3048it searches for a matching named list of any type (domain, host, address, or
3049local part) and outputs what it finds.
9b371988
PH
3050
3051.cindex "options" "router &-- extracting"
3052.cindex "options" "transport &-- extracting"
5d9c27ec 3053.cindex "options" "authenticator &-- extracting"
9b371988 3054If one of the words &%router%&, &%transport%&, or &%authenticator%& is given,
168e428f
PH
3055followed by the name of an appropriate driver instance, the option settings for
3056that driver are output. For example:
9b371988
PH
3057.code
3058exim -bP transport local_delivery
3059.endd
168e428f
PH
3060The generic driver options are output first, followed by the driver's private
3061options. A list of the names of drivers of a particular type can be obtained by
9b371988
PH
3062using one of the words &%router_list%&, &%transport_list%&, or
3063&%authenticator_list%&, and a complete list of all drivers with their option
3064settings can be obtained by using &%routers%&, &%transports%&, or
3065&%authenticators%&.