Typo.
[exim.git] / doc / doc-docbook / spec.xfpt
CommitLineData
0b5038ed 1. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.37 2008/02/18 18:32:31 fanf2 Exp $
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2.
3. /////////////////////////////////////////////////////////////////////////////
4. This is the primary source of the Exim Manual. It is an xfpt document that is
5. converted into DocBook XML for subsequent conversion into printing and online
6. formats. The markup used herein is "standard" xfpt markup, with some extras.
7. The markup is summarized in a file called Markup.txt.
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8.
9. WARNING: When you use the .new macro, make sure it appears *before* any
10. adjacent index items; otherwise you get an empty "paragraph" which causes
11. unwanted vertical space.
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12. /////////////////////////////////////////////////////////////////////////////
13
14.include stdflags
15.include stdmacs
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16
17. /////////////////////////////////////////////////////////////////////////////
33393583 18. This outputs the standard DocBook boilerplate.
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19. /////////////////////////////////////////////////////////////////////////////
20
33393583 21.docbook
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22
23. /////////////////////////////////////////////////////////////////////////////
24. These lines are processing instructions for the Simple DocBook Processor that
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25. Philip Hazel has developed as a less cumbersome way of making PostScript and
26. PDFs than using xmlto and fop. They will be ignored by all other XML
27. processors.
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28. /////////////////////////////////////////////////////////////////////////////
29
30.literal xml
31<?sdop
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32 foot_right_recto="&chaptertitle; (&chapternumber;)"
33 foot_right_verso="&chaptertitle; (&chapternumber;)"
3cb1b51e 34 toc_chapter_blanks="yes,yes"
595028e4 35 table_warn_overflow="overprint"
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36?>
37.literal off
9b371988 38
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39. /////////////////////////////////////////////////////////////////////////////
40. This generate the outermost <book> element that wraps then entire document.
41. /////////////////////////////////////////////////////////////////////////////
42
43.book
44
45. /////////////////////////////////////////////////////////////////////////////
46. These definitions set some parameters and save some typing. Remember that
47. the <bookinfo> element must also be updated for each new edition.
48. /////////////////////////////////////////////////////////////////////////////
49
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50.set previousversion "4.69"
51.set version "4.70"
f89d2485 52
33393583 53.set ACL "access control lists (ACLs)"
f89d2485 54.set I "&nbsp;&nbsp;&nbsp;&nbsp;"
33393583 55
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56
57. /////////////////////////////////////////////////////////////////////////////
58. Additional xfpt markup used by this document, over and above the default
59. provided in the xfpt library.
60. /////////////////////////////////////////////////////////////////////////////
61
62. --- Override the &$ flag to automatically insert a $ with the variable name
63
64.flag &$ $& "<varname>$" "</varname>"
65
66. --- Short flags for daggers in option headings. They will always be inside
67. --- an italic string, but we want the daggers to be roman.
68
69.flag &!! "</emphasis>&dagger;<emphasis>"
70.flag &!? "</emphasis>&Dagger;<emphasis>"
71
72. --- A macro for an Exim option definition heading, generating a one-line
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73. --- table with four columns. For cases when the option name is given with
74. --- a space, so that it can be split, a fifth argument is used for the
75. --- index entry.
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76
77.macro option
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78.arg 5
79.oindex "&%$5%&"
80.endarg
81.arg -5
3cb1b51e 82.oindex "&%$1%&"
0a4e3112 83.endarg
f89d2485 84.itable all 0 0 4 8* left 6* center 6* center 6* right
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85.row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&"
86.endtable
87.endmacro
88
89. --- A macro for the common 2-column tables. The width of the first column
90. --- is suitable for the many tables at the start of the main options chapter;
91. --- the small number of other 2-column tables override it.
92
db9452a9 93.macro table2 196pt 254pt
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94.itable none 0 0 2 $1 left $2 left
95.endmacro
96
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97. --- A macro that generates .row, but puts &I; at the start of the first
98. --- argument, thus indenting it. Assume a minimum of two arguments, and
99. --- allow up to four arguments, which is as many as we'll ever need.
100
101.macro irow
102.arg 4
103.row "&I;$1" "$2" "$3" "$4"
104.endarg
105.arg -4
106.arg 3
107.row "&I;$1" "$2" "$3"
108.endarg
109.arg -3
110.row "&I;$1" "$2"
111.endarg
112.endarg
113.endmacro
114
115. --- Macros for option, variable, and concept index entries. For a "range"
116. --- style of entry, use .scindex for the start and .ecindex for the end. The
117. --- first argument of .scindex and the only argument of .ecindex must be the
118. --- ID that ties them together.
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119
120.macro cindex
121&<indexterm role="concept">&
122&<primary>&$1&</primary>&
123.arg 2
124&<secondary>&$2&</secondary>&
125.endarg
126&</indexterm>&
127.endmacro
128
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129.macro scindex
130&<indexterm role="concept" id="$1" class="startofrange">&
131&<primary>&$2&</primary>&
132.arg 3
133&<secondary>&$3&</secondary>&
134.endarg
135&</indexterm>&
136.endmacro
137
138.macro ecindex
139&<indexterm role="concept" startref="$1" class="endofrange"/>&
140.endmacro
141
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142.macro oindex
143&<indexterm role="option">&
144&<primary>&$1&</primary>&
145.arg 2
146&<secondary>&$2&</secondary>&
147.endarg
148&</indexterm>&
149.endmacro
150
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151.macro vindex
152&<indexterm role="variable">&
153&<primary>&$1&</primary>&
154.arg 2
155&<secondary>&$2&</secondary>&
156.endarg
157&</indexterm>&
158.endmacro
159
9b371988 160.macro index
f89d2485 161.echo "** Don't use .index; use .cindex or .oindex or .vindex"
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162.endmacro
163. ////////////////////////////////////////////////////////////////////////////
164
165
166. ////////////////////////////////////////////////////////////////////////////
167. The <bookinfo> element is removed from the XML before processing for Ascii
168. output formats.
169. ////////////////////////////////////////////////////////////////////////////
170
171.literal xml
172<bookinfo>
173<title>Specification of the Exim Mail Transfer Agent</title>
174<titleabbrev>The Exim MTA</titleabbrev>
595028e4 175<date>23 August 2007</date>
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176<author><firstname>Philip</firstname><surname>Hazel</surname></author>
177<authorinitials>PH</authorinitials>
178<affiliation><orgname>University of Cambridge Computing Service</orgname></affiliation>
179<address>New Museums Site, Pembroke Street, Cambridge CB2 3QH, England</address>
180<revhistory><revision>
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181 <revnumber>4.68</revnumber>
182 <date>23 August 2007</date>
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183 <authorinitials>PH</authorinitials>
184</revision></revhistory>
ad268134 185<copyright><year>2007</year><holder>University of Cambridge</holder></copyright>
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186</bookinfo>
187.literal off
188
189
190. /////////////////////////////////////////////////////////////////////////////
191. This chunk of literal XML implements index entries of the form "x, see y" and
192. "x, see also y". However, the DocBook DTD doesn't allow <indexterm> entries
193. at the top level, so we have to put the .chapter directive first.
194. /////////////////////////////////////////////////////////////////////////////
195
f89d2485 196.chapter "Introduction" "CHID1"
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197.literal xml
198
f89d2485 199<indexterm role="variable">
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200 <primary>$1, $2, etc.</primary>
201 <see><emphasis>numerical variables</emphasis></see>
202</indexterm>
203<indexterm role="concept">
204 <primary>address</primary>
205 <secondary>rewriting</secondary>
206 <see><emphasis>rewriting</emphasis></see>
207</indexterm>
208<indexterm role="concept">
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209 <primary>Bounce Address Tag Validation</primary>
210 <see><emphasis>BATV</emphasis></see>
211</indexterm>
212<indexterm role="concept">
213 <primary>Client SMTP Authorization</primary>
214 <see><emphasis>CSA</emphasis></see>
215</indexterm>
216<indexterm role="concept">
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217 <primary>CR character</primary>
218 <see><emphasis>carriage return</emphasis></see>
219</indexterm>
220<indexterm role="concept">
221 <primary>CRL</primary>
222 <see><emphasis>certificate revocation list</emphasis></see>
223</indexterm>
224<indexterm role="concept">
225 <primary>delivery</primary>
226 <secondary>failure report</secondary>
227 <see><emphasis>bounce message</emphasis></see>
228</indexterm>
229<indexterm role="concept">
230 <primary>dialup</primary>
231 <see><emphasis>intermittently connected hosts</emphasis></see>
232</indexterm>
233<indexterm role="concept">
234 <primary>exiscan</primary>
235 <see><emphasis>content scanning</emphasis></see>
236</indexterm>
237<indexterm role="concept">
238 <primary>failover</primary>
239 <see><emphasis>fallback</emphasis></see>
240</indexterm>
241<indexterm role="concept">
242 <primary>fallover</primary>
243 <see><emphasis>fallback</emphasis></see>
244</indexterm>
245<indexterm role="concept">
246 <primary>filter</primary>
247 <secondary>Sieve</secondary>
248 <see><emphasis>Sieve filter</emphasis></see>
249</indexterm>
250<indexterm role="concept">
251 <primary>ident</primary>
252 <see><emphasis>RFC 1413</emphasis></see>
253</indexterm>
254<indexterm role="concept">
255 <primary>LF character</primary>
256 <see><emphasis>linefeed</emphasis></see>
257</indexterm>
258<indexterm role="concept">
259 <primary>maximum</primary>
595028e4 260 <seealso><emphasis>limit</emphasis></seealso>
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261</indexterm>
262<indexterm role="concept">
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263 <primary>monitor</primary>
264 <see><emphasis>Exim monitor</emphasis></see>
265</indexterm>
266<indexterm role="concept">
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267 <primary>no_<emphasis>xxx</emphasis></primary>
268 <see>entry for xxx</see>
269</indexterm>
270<indexterm role="concept">
271 <primary>NUL</primary>
272 <see><emphasis>binary zero</emphasis></see>
273</indexterm>
274<indexterm role="concept">
275 <primary>passwd file</primary>
276 <see><emphasis>/etc/passwd</emphasis></see>
277</indexterm>
278<indexterm role="concept">
279 <primary>process id</primary>
280 <see><emphasis>pid</emphasis></see>
281</indexterm>
282<indexterm role="concept">
283 <primary>RBL</primary>
284 <see><emphasis>DNS list</emphasis></see>
285</indexterm>
286<indexterm role="concept">
287 <primary>redirection</primary>
288 <see><emphasis>address redirection</emphasis></see>
289</indexterm>
290<indexterm role="concept">
291 <primary>return path</primary>
292 <seealso><emphasis>envelope sender</emphasis></seealso>
293</indexterm>
294<indexterm role="concept">
295 <primary>scanning</primary>
296 <see><emphasis>content scanning</emphasis></see>
297</indexterm>
298<indexterm role="concept">
299 <primary>SSL</primary>
300 <see><emphasis>TLS</emphasis></see>
301</indexterm>
302<indexterm role="concept">
303 <primary>string</primary>
304 <secondary>expansion</secondary>
305 <see><emphasis>expansion</emphasis></see>
306</indexterm>
307<indexterm role="concept">
308 <primary>top bit</primary>
309 <see><emphasis>8-bit characters</emphasis></see>
310</indexterm>
311<indexterm role="concept">
312 <primary>variables</primary>
313 <see><emphasis>expansion, variables</emphasis></see>
314</indexterm>
315<indexterm role="concept">
316 <primary>zero, binary</primary>
317 <see><emphasis>binary zero</emphasis></see>
318</indexterm>
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319
320.literal off
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321
322
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323. /////////////////////////////////////////////////////////////////////////////
324. This is the real start of the first chapter. See the comment above as to why
325. we can't have the .chapter line here.
326. chapter "Introduction"
327. /////////////////////////////////////////////////////////////////////////////
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328
329Exim is a mail transfer agent (MTA) for hosts that are running Unix or
330Unix-like operating systems. It was designed on the assumption that it would be
331run on hosts that are permanently connected to the Internet. However, it can be
332used on intermittently connected hosts with suitable configuration adjustments.
333
334Configuration files currently exist for the following operating systems: AIX,
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335BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, Dragonfly, FreeBSD, GNU/Hurd,
336GNU/Linux, HI-OSF (Hitachi), HI-UX, HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD,
337OpenUNIX, QNX, SCO, SCO SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4,
338Tru64-Unix (formerly Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware.
339Some of these operating systems are no longer current and cannot easily be
340tested, so the configuration files may no longer work in practice.
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341
342There are also configuration files for compiling Exim in the Cygwin environment
343that can be installed on systems running Windows. However, this document does
344not contain any information about running Exim in the Cygwin environment.
345
346The terms and conditions for the use and distribution of Exim are contained in
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347the file &_NOTICE_&. Exim is distributed under the terms of the GNU General
348Public Licence, a copy of which may be found in the file &_LICENCE_&.
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349
350The use, supply or promotion of Exim for the purpose of sending bulk,
351unsolicited electronic mail is incompatible with the basic aims of the program,
352which revolve around the free provision of a service that enhances the quality
353of personal communications. The author of Exim regards indiscriminate
354mass-mailing as an antisocial, irresponsible abuse of the Internet.
355
356Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
357experience of running and working on the Smail 3 code, I could never have
358contemplated starting to write a new MTA. Many of the ideas and user interfaces
359were originally taken from Smail 3, though the actual code of Exim is entirely
360new, and has developed far beyond the initial concept.
361
362Many people, both in Cambridge and around the world, have contributed to the
363development and the testing of Exim, and to porting it to various operating
364systems. I am grateful to them all. The distribution now contains a file called
9b371988 365&_ACKNOWLEDGMENTS_&, in which I have started recording the names of
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366contributors.
367
368
f89d2485 369.section "Exim documentation" "SECID1"
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370. Keep this example change bar when updating the documentation!
371.new
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372.cindex "documentation"
373This edition of the Exim specification applies to version &version; of Exim.
374Substantive changes from the &previousversion; edition are marked in some
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375renditions of the document; this paragraph is so marked if the rendition is
376capable of showing a change indicator.
800d5176 377.wen
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378
379This document is very much a reference manual; it is not a tutorial. The reader
380is expected to have some familiarity with the SMTP mail transfer protocol and
381with general Unix system administration. Although there are some discussions
382and examples in places, the information is mostly organized in a way that makes
383it easy to look up, rather than in a natural order for sequential reading.
384Furthermore, the manual aims to cover every aspect of Exim in detail, including
385a number of rarely-used, special-purpose features that are unlikely to be of
386very wide interest.
387
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388.cindex "books about Exim"
389An &"easier"& discussion of Exim which provides more in-depth explanatory,
390introductory, and tutorial material can be found in a book entitled &'The Exim
595028e4 391SMTP Mail Server'& (second edition, 2007), published by UIT Cambridge
9b371988 392(&url(http://www.uit.co.uk/exim-book/)).
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393
394This book also contains a chapter that gives a general introduction to SMTP and
395Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
396with the latest release of Exim. (Note that the earlier book about Exim,
397published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
398
9b371988 399.cindex "Debian" "information sources"
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400If you are using a Debian distribution of Exim, you will find information about
401Debian-specific features in the file
f89d2485 402&_/usr/share/doc/exim4-base/README.Debian_&.
9b371988 403The command &(man update-exim.conf)& is another source of Debian-specific
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404information.
405
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406.cindex "&_doc/NewStuff_&"
407.cindex "&_doc/ChangeLog_&"
408.cindex "change log"
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409As the program develops, there may be features in newer versions that have not
410yet made it into this document, which is updated only when the most significant
411digit of the fractional part of the version number changes. Specifications of
412new features that are not yet in this manual are placed in the file
9b371988 413&_doc/NewStuff_& in the Exim distribution.
168e428f 414
9b371988 415Some features may be classified as &"experimental"&. These may change
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416incompatibly while they are developing, or even be withdrawn. For this reason,
417they are not documented in this manual. Information about experimental features
9b371988 418can be found in the file &_doc/experimental.txt_&.
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419
420All changes to the program (whether new features, bug fixes, or other kinds of
9b371988 421change) are noted briefly in the file called &_doc/ChangeLog_&.
168e428f 422
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423.cindex "&_doc/spec.txt_&"
424This specification itself is available as an ASCII file in &_doc/spec.txt_& so
425that it can easily be searched with a text editor. Other files in the &_doc_&
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426directory are:
427
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428.table2 100pt
429.row &_OptionLists.txt_& "list of all options in alphabetical order"
430.row &_dbm.discuss.txt_& "discussion about DBM libraries"
431.row &_exim.8_& "a man page of Exim's command line options"
432.row &_experimental.txt_& "documentation of experimental features"
433.row &_filter.txt_& "specification of the filter language"
434.row &_pcrepattern.txt_& "specification of PCRE regular expressions"
435.row &_pcretest.txt_& "specification of the PCRE testing program"
436.row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
437.row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
438.endtable
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439
440The main specification and the specification of the filtering language are also
441available in other formats (HTML, PostScript, PDF, and Texinfo). Section
9b371988 442&<<SECTavail>>& below tells you how to get hold of these.
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443
444
445
f89d2485 446.section "FTP and web sites" "SECID2"
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447.cindex "web site"
448.cindex "FTP site"
068aaea8 449The primary site for Exim source distributions is currently the University of
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450Cambridge's FTP site, whose contents are described in &'Where to find the Exim
451distribution'& below. In addition, there is a web site and an FTP site at
452&%exim.org%&. These are now also hosted at the University of Cambridge. The
453&%exim.org%& site was previously hosted for a number of years by Energis
454Squared, formerly Planet Online Ltd, whose support I gratefully acknowledge.
455
456.cindex "wiki"
457.cindex "FAQ"
168e428f 458As well as Exim distribution tar files, the Exim web site contains a number of
f89d2485 459differently formatted versions of the documentation. A recent addition to the
7d0ab55c 460online information is the Exim wiki (&url(http://wiki.exim.org)),
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461which contains what used to be a separate FAQ, as well as various other
462examples, tips, and know-how that have been contributed by Exim users.
463
464.cindex Bugzilla
7d0ab55c 465An Exim Bugzilla exists at &url(http://bugs.exim.org). You can use
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466this to report bugs, and also to add items to the wish list. Please search
467first to check that you are not duplicating a previous entry.
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468
469
470
f89d2485 471.section "Mailing lists" "SECID3"
9b371988 472.cindex "mailing lists" "for Exim users"
f89d2485 473The following Exim mailing lists exist:
168e428f 474
9b371988 475.table2 140pt
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476.row &'exim-users@exim.org'& "General discussion list"
477.row &'exim-dev@exim.org'& "Discussion of bugs, enhancements, etc."
478.row &'exim-announce@exim.org'& "Moderated, low volume announcements list"
479.row &'exim-future@exim.org'& "Discussion of long-term development"
9b371988 480.endtable
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481
482You can subscribe to these lists, change your existing subscriptions, and view
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483or search the archives via the mailing lists link on the Exim home page.
484.cindex "Debian" "mailing list for"
4f578862 485If you are using a Debian distribution of Exim, you may wish to subscribe to
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486the Debian-specific mailing list &'pkg-exim4-users@lists.alioth.debian.org'&
487via this web page:
488.display
489&url(http://lists.alioth.debian.org/mailman/listinfo/pkg-exim4-users)
490.endd
491Please ask Debian-specific questions on this list and not on the general Exim
492lists.
9b371988 493
f89d2485 494.section "Exim training" "SECID4"
9b371988 495.cindex "training courses"
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496Training courses in Cambridge (UK) used to be run annually by the author of
497Exim, before he retired. At the time of writing, there are no plans to run
498further Exim courses in Cambridge. However, if that changes, relevant
499information will be posted at &url(http://www-tus.csx.cam.ac.uk/courses/exim/).
168e428f 500
f89d2485 501.section "Bug reports" "SECID5"
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502.cindex "bug reports"
503.cindex "reporting bugs"
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504Reports of obvious bugs can be emailed to &'bugs@exim.org'& or reported
505via the Bugzilla (&url(http://bugs.exim.org)). However, if you are unsure
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506whether some behaviour is a bug or not, the best thing to do is to post a
507message to the &'exim-dev'& mailing list and have it discussed.
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508
509
510
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511.section "Where to find the Exim distribution" "SECTavail"
512.cindex "FTP site"
513.cindex "distribution" "ftp site"
168e428f 514The master ftp site for the Exim distribution is
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515.display
516&*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim*&
517.endd
168e428f 518This is mirrored by
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519.display
520&*ftp://ftp.exim.org/pub/exim*&
521.endd
522The file references that follow are relative to the &_exim_& directories at
523these sites. There are now quite a number of independent mirror sites around
524the world. Those that I know about are listed in the file called &_Mirrors_&.
525
526Within the &_exim_& directory there are subdirectories called &_exim3_& (for
527previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
528distributions), and &_Testing_& for testing versions. In the &_exim4_&
168e428f 529subdirectory, the current release can always be found in files called
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530.display
531&_exim-n.nn.tar.gz_&
532&_exim-n.nn.tar.bz2_&
533.endd
534where &'n.nn'& is the highest such version number in the directory. The two
168e428f 535files contain identical data; the only difference is the type of compression.
9b371988 536The &_.bz2_& file is usually a lot smaller than the &_.gz_& file.
168e428f 537
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538.cindex "distribution" "signing details"
539.cindex "distribution" "public key"
540.cindex "public key for signed distribution"
210f147e 541The distributions are currently signed with Nigel Metheringham's GPG key. The
168e428f 542corresponding public key is available from a number of keyservers, and there is
210f147e 543also a copy in the file &_nigel-pubkey.asc_&. The signatures for the tar bundles are
168e428f 544in:
9b371988 545.display
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546&_exim-n.nn.tar.gz.asc_&
547&_exim-n.nn.tar.bz2.asc_&
9b371988 548.endd
168e428f 549For each released version, the log of changes is made separately available in a
9b371988 550separate file in the directory &_ChangeLogs_& so that it is possible to
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551find out what has changed without having to download the entire distribution.
552
9b371988 553.cindex "documentation" "available formats"
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554The main distribution contains ASCII versions of this specification and other
555documentation; other formats of the documents are available in separate files
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556inside the &_exim4_& directory of the FTP site:
557.display
558&_exim-html-n.nn.tar.gz_&
559&_exim-pdf-n.nn.tar.gz_&
560&_exim-postscript-n.nn.tar.gz_&
561&_exim-texinfo-n.nn.tar.gz_&
562.endd
563These tar files contain only the &_doc_& directory, not the complete
564distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
168e428f 565
168e428f 566
f89d2485 567.section "Limitations" "SECID6"
9b371988
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568.ilist
569.cindex "limitations of Exim"
570.cindex "bang paths" "not handled by Exim"
571Exim is designed for use as an Internet MTA, and therefore handles addresses in
572RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
573simple two-component bang paths can be converted by a straightforward rewriting
574configuration. This restriction does not prevent Exim from being interfaced to
575UUCP as a transport mechanism, provided that domain addresses are used.
576.next
577.cindex "domainless addresses"
578.cindex "address" "without domain"
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579Exim insists that every address it handles has a domain attached. For incoming
580local messages, domainless addresses are automatically qualified with a
581configured domain value. Configuration options specify from which remote
582systems unqualified addresses are acceptable. These are then qualified on
583arrival.
9b371988
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584.next
585.cindex "transport" "external"
586.cindex "external transports"
587The only external transport mechanisms that are currently implemented are SMTP
588and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
168e428f 589transport is available, and there are facilities for writing messages to files
9b371988
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590and pipes, optionally in &'batched SMTP'& format; these facilities can be used
591to send messages to other transport mechanisms such as UUCP, provided they can
592handle domain-style addresses. Batched SMTP input is also catered for.
593.next
594Exim is not designed for storing mail for dial-in hosts. When the volumes of
595such mail are large, it is better to get the messages &"delivered"& into files
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596(that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
597other means.
9b371988
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598.next
599Although Exim does have basic facilities for scanning incoming messages, these
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600are not comprehensive enough to do full virus or spam scanning. Such operations
601are best carried out using additional specialized software packages. If you
602compile Exim with the content-scanning extension, straightforward interfaces to
603a number of common scanners are provided.
9b371988 604.endlist
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605
606
f89d2485 607.section "Run time configuration" "SECID7"
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608Exim's run time configuration is held in a single text file that is divided
609into a number of sections. The entries in this file consist of keywords and
610values, in the style of Smail 3 configuration files. A default configuration
611file which is suitable for simple online installations is provided in the
9b371988 612distribution, and is described in chapter &<<CHAPdefconfil>>& below.
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613
614
f89d2485 615.section "Calling interface" "SECID8"
9b371988 616.cindex "Sendmail compatibility" "command line interface"
168e428f 617Like many MTAs, Exim has adopted the Sendmail command line interface so that it
9b371988
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618can be a straight replacement for &_/usr/lib/sendmail_& or
619&_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
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620about Sendmail in order to run Exim. For actions other than sending messages,
621Sendmail-compatible options also exist, but those that produce output (for
9b371988 622example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
168e428f 623format. There are also some additional options that are compatible with Smail
9b371988 6243, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
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625documents all Exim's command line options. This information is automatically
626made into the man page that forms part of the Exim distribution.
627
628Control of messages on the queue can be done via certain privileged command
9b371988
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629line options. There is also an optional monitor program called &'eximon'&,
630which displays current information in an X window, and which contains a menu
168e428f
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631interface to Exim's command line administration options.
632
633
634
f89d2485 635.section "Terminology" "SECID9"
9b371988
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636.cindex "terminology definitions"
637.cindex "body of message" "definition of"
638The &'body'& of a message is the actual data that the sender wants to transmit.
639It is the last part of a message, and is separated from the &'header'& (see
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640below) by a blank line.
641
9b371988 642.cindex "bounce message" "definition of"
168e428f 643When a message cannot be delivered, it is normally returned to the sender in a
9b371988
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644delivery failure message or a &"non-delivery report"& (NDR). The term
645&'bounce'& is commonly used for this action, and the error reports are often
646called &'bounce messages'&. This is a convenient shorthand for &"delivery
647failure error report"&. Such messages have an empty sender address in the
648message's &'envelope'& (see below) to ensure that they cannot themselves give
649rise to further bounce messages.
650
651The term &'default'& appears frequently in this manual. It is used to qualify a
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652value which is used in the absence of any setting in the configuration. It may
653also qualify an action which is taken unless a configuration setting specifies
654otherwise.
655
9b371988 656The term &'defer'& is used when the delivery of a message to a specific
168e428f 657destination cannot immediately take place for some reason (a remote host may be
9b371988 658down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
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659until a later time.
660
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661The word &'domain'& is sometimes used to mean all but the first component of a
662host's name. It is &'not'& used in that sense here, where it normally refers to
663the part of an email address following the @ sign.
168e428f 664
f89d2485 665.cindex "envelope, definition of"
9b371988
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666.cindex "sender" "definition of"
667A message in transit has an associated &'envelope'&, as well as a header and a
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668body. The envelope contains a sender address (to which bounce messages should
669be delivered), and any number of recipient addresses. References to the
670sender or the recipients of a message usually mean the addresses in the
671envelope. An MTA uses these addresses for delivery, and for returning bounce
672messages, not the addresses that appear in the header lines.
673
f89d2485 674.cindex "message" "header, definition of"
9b371988
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675.cindex "header section" "definition of"
676The &'header'& of a message is the first part of a message's text, consisting
677of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
678&'Subject:'&, etc. Long header lines can be split over several text lines by
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679indenting the continuations. The header is separated from the body by a blank
680line.
681
9b371988
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682.cindex "local part" "definition of"
683.cindex "domain" "definition of"
684The term &'local part'&, which is taken from RFC 2822, is used to refer to that
168e428f 685part of an email address that precedes the @ sign. The part that follows the
9b371988 686@ sign is called the &'domain'& or &'mail domain'&.
168e428f 687
9b371988 688.cindex "local delivery" "definition of"
f89d2485 689.cindex "remote delivery, definition of"
9b371988 690The terms &'local delivery'& and &'remote delivery'& are used to distinguish
168e428f 691delivery to a file or a pipe on the local host from delivery by SMTP over
068aaea8 692TCP/IP to another host. As far as Exim is concerned, all hosts other than the
9b371988 693host it is running on are &'remote'&.
168e428f 694
9b371988
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695.cindex "return path" "definition of"
696&'Return path'& is another name that is used for the sender address in a
168e428f
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697message's envelope.
698
9b371988
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699.cindex "queue" "definition of"
700The term &'queue'& is used to refer to the set of messages awaiting delivery,
168e428f
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701because this term is in widespread use in the context of MTAs. However, in
702Exim's case the reality is more like a pool than a queue, because there is
703normally no ordering of waiting messages.
704
9b371988
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705.cindex "queue runner" "definition of"
706The term &'queue runner'& is used to describe a process that scans the queue
168e428f 707and attempts to deliver those messages whose retry times have come. This term
9b371988 708is used by other MTAs, and also relates to the command &%runq%&, but in Exim
168e428f
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709the waiting messages are normally processed in an unpredictable order.
710
9b371988
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711.cindex "spool directory" "definition of"
712The term &'spool directory'& is used for a directory in which Exim keeps the
713messages on its queue &-- that is, those that it is in the process of
168e428f 714delivering. This should not be confused with the directory in which local
9b371988
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715mailboxes are stored, which is called a &"spool directory"& by some people. In
716the Exim documentation, &"spool"& is always used in the first sense.
168e428f
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717
718
719
720
721
722
9b371988
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723. ////////////////////////////////////////////////////////////////////////////
724. ////////////////////////////////////////////////////////////////////////////
168e428f 725
f89d2485 726.chapter "Incorporated code" "CHID2"
9b371988
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727.cindex "incorporated code"
728.cindex "regular expressions" "library"
729.cindex "PCRE"
168e428f
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730A number of pieces of external code are included in the Exim distribution.
731
9b371988 732.ilist
210f147e
NM
733Regular expressions are supported in the main Exim program and in the
734Exim monitor using the freely-distributable PCRE library, copyright
735&copy; University of Cambridge. The source to a cut down version of PCRE
736used to be distributed in the directory &_src/pcre_&. However, this is
737no longer the case and you will need to use a system PCRE library or
738obtain and install the full version of the library from
f89d2485 739&url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
9b371988 740.next
f89d2485 741.cindex "cdb" "acknowledgment"
168e428f
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742Support for the cdb (Constant DataBase) lookup method is provided by code
743contributed by Nigel Metheringham of (at the time he contributed it) Planet
9b371988
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744Online Ltd. The implementation is completely contained within the code of Exim.
745It does not link against an external cdb library. The code contains the
746following statements:
747
748.blockquote
749Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
750
168e428f
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751This program is free software; you can redistribute it and/or modify it under
752the terms of the GNU General Public License as published by the Free Software
753Foundation; either version 2 of the License, or (at your option) any later
754version.
168e428f
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755This code implements Dan Bernstein's Constant DataBase (cdb) spec. Information,
756the spec and sample code for cdb can be obtained from
f89d2485
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757&url(http://www.pobox.com/~djb/cdb.html). This implementation borrows
758some code from Dan Bernstein's implementation (which has no license
759restrictions applied to it).
9b371988
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760.endblockquote
761.next
762.cindex "SPA authentication"
763.cindex "Samba project"
764.cindex "Microsoft Secure Password Authentication"
765Client support for Microsoft's &'Secure Password Authentication'& is provided
168e428f
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766by code contributed by Marc Prud'hommeaux. Server support was contributed by
767Tom Kistner. This includes code taken from the Samba project, which is released
768under the Gnu GPL.
9b371988
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769.next
770.cindex "Cyrus"
771.cindex "&'pwcheck'& daemon"
772.cindex "&'pwauthd'& daemon"
773Support for calling the Cyrus &'pwcheck'& and &'saslauthd'& daemons is provided
168e428f
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774by code taken from the Cyrus-SASL library and adapted by Alexander S.
775Sabourenkov. The permission notice appears below, in accordance with the
776conditions expressed therein.
9b371988
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777
778.blockquote
779Copyright &copy; 2001 Carnegie Mellon University. All rights reserved.
780
168e428f
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781Redistribution and use in source and binary forms, with or without
782modification, are permitted provided that the following conditions
783are met:
168e428f 784
9b371988
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785.olist
786Redistributions of source code must retain the above copyright
787notice, this list of conditions and the following disclaimer.
788.next
789Redistributions in binary form must reproduce the above copyright
168e428f
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790notice, this list of conditions and the following disclaimer in
791the documentation and/or other materials provided with the
792distribution.
9b371988
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793.next
794The name &"Carnegie Mellon University"& must not be used to
168e428f
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795endorse or promote products derived from this software without
796prior written permission. For permission or any other legal
797details, please contact
9b371988 798.display
068aaea8
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799 Office of Technology Transfer
800 Carnegie Mellon University
801 5000 Forbes Avenue
802 Pittsburgh, PA 15213-3890
803 (412) 268-4387, fax: (412) 268-7395
804 tech-transfer@andrew.cmu.edu
9b371988
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805.endd
806.next
807Redistributions of any form whatsoever must retain the following
168e428f 808acknowledgment:
9b371988
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809
810&"This product includes software developed by Computing Services
811at Carnegie Mellon University (&url(http://www.cmu.edu/computing/)."&
812
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813CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
814THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
815AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
816FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
817WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
818AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
819OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
9b371988
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820.endlist
821.endblockquote
168e428f 822
9b371988 823.next
f89d2485 824.cindex "Exim monitor" "acknowledgment"
9b371988
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825.cindex "X-windows"
826.cindex "Athena"
168e428f
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827The Exim Monitor program, which is an X-Window application, includes
828modified versions of the Athena StripChart and TextPop widgets.
829This code is copyright by DEC and MIT, and their permission notice appears
830below, in accordance with the conditions expressed therein.
9b371988
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831
832.blockquote
168e428f
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833Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts,
834and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
9b371988 835
168e428f 836All Rights Reserved
9b371988 837
168e428f
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838Permission to use, copy, modify, and distribute this software and its
839documentation for any purpose and without fee is hereby granted,
840provided that the above copyright notice appear in all copies and that
841both that copyright notice and this permission notice appear in
842supporting documentation, and that the names of Digital or MIT not be
843used in advertising or publicity pertaining to distribution of the
844software without specific, written prior permission.
9b371988 845
168e428f
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846DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
847ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
848DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
849ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
850WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
851ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
852SOFTWARE.
9b371988 853.endblockquote
168e428f 854
9b371988
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855.next
856Many people have contributed code fragments, some large, some small, that were
168e428f 857not covered by any specific licence requirements. It is assumed that the
f89d2485 858contributors are happy to see their code incorporated into Exim under the GPL.
9b371988 859.endlist
168e428f
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860
861
862
863
864
9b371988
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865. ////////////////////////////////////////////////////////////////////////////
866. ////////////////////////////////////////////////////////////////////////////
168e428f 867
f89d2485 868.chapter "How Exim receives and delivers mail" "CHID11" &&&
9b371988 869 "Receiving and delivering mail"
168e428f
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870
871
f89d2485 872.section "Overall philosophy" "SECID10"
9b371988 873.cindex "design philosophy"
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874Exim is designed to work efficiently on systems that are permanently connected
875to the Internet and are handling a general mix of mail. In such circumstances,
876most messages can be delivered immediately. Consequently, Exim does not
877maintain independent queues of messages for specific domains or hosts, though
878it does try to send several messages in a single SMTP connection after a host
879has been down, and it also maintains per-host retry information.
880
881
f89d2485 882.section "Policy control" "SECID11"
9b371988 883.cindex "policy control" "overview"
168e428f
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884Policy controls are now an important feature of MTAs that are connected to the
885Internet. Perhaps their most important job is to stop MTAs being abused as
9b371988
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886&"open relays"& by misguided individuals who send out vast amounts of
887unsolicited junk, and want to disguise its source. Exim provides flexible
888facilities for specifying policy controls on incoming mail:
168e428f 889
9b371988
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890.ilist
891.cindex "&ACL;" "introduction"
168e428f 892Exim 4 (unlike previous versions of Exim) implements policy controls on
9b371988 893incoming mail by means of &'Access Control Lists'& (ACLs). Each list is a
168e428f
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894series of statements that may either grant or deny access. ACLs can be used at
895several places in the SMTP dialogue while receiving a message from a remote
9b371988
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896host. However, the most common places are after each RCPT command, and at the
897very end of the message. The sysadmin can specify conditions for accepting or
898rejecting individual recipients or the entire message, respectively, at these
899two points (see chapter &<<CHAPACL>>&). Denial of access results in an SMTP
168e428f 900error code.
9b371988
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901.next
902An ACL is also available for locally generated, non-SMTP messages. In this
168e428f 903case, the only available actions are to accept or deny the entire message.
9b371988
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904.next
905When Exim is compiled with the content-scanning extension, facilities are
168e428f
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906provided in the ACL mechanism for passing the message to external virus and/or
907spam scanning software. The result of such a scan is passed back to the ACL,
908which can then use it to decide what to do with the message.
9b371988
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909.next
910When a message has been received, either from a remote host or from the local
f89d2485 911host, but before the final acknowledgment has been sent, a locally supplied C
9b371988
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912function called &[local_scan()]& can be run to inspect the message and decide
913whether to accept it or not (see chapter &<<CHAPlocalscan>>&). If the message
914is accepted, the list of recipients can be modified by the function.
915.next
916Using the &[local_scan()]& mechanism is another way of calling external scanner
917software. The &%SA-Exim%& add-on package works this way. It does not require
918Exim to be compiled with the content-scanning extension.
919.next
920After a message has been accepted, a further checking mechanism is available in
921the form of the &'system filter'& (see chapter &<<CHAPsystemfilter>>&). This
922runs at the start of every delivery process.
923.endlist
924
925
926
f89d2485 927.section "User filters" "SECID12"
9b371988
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928.cindex "filter" "introduction"
929.cindex "Sieve filter"
168e428f 930In a conventional Exim configuration, users are able to run private filters by
9b371988
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931setting up appropriate &_.forward_& files in their home directories. See
932chapter &<<CHAPredirect>>& (about the &(redirect)& router) for the
933configuration needed to support this, and the separate document entitled
934&'Exim's interfaces to mail filtering'& for user details. Two different kinds
935of filtering are available:
936
937.ilist
938Sieve filters are written in the standard filtering language that is defined
168e428f 939by RFC 3028.
9b371988
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940.next
941Exim filters are written in a syntax that is unique to Exim, but which is more
168e428f 942powerful than Sieve, which it pre-dates.
9b371988 943.endlist
168e428f
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944
945User filters are run as part of the routing process, described below.
946
947
948
9b371988
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949.section "Message identification" "SECTmessiden"
950.cindex "message ids" "details of format"
951.cindex "format" "of message id"
952.cindex "id of message"
953.cindex "base62"
954.cindex "base36"
955.cindex "Darwin"
956.cindex "Cygwin"
957Every message handled by Exim is given a &'message id'& which is sixteen
168e428f 958characters long. It is divided into three parts, separated by hyphens, for
9b371988 959example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits,
168e428f
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960normally encoding numbers in base 62. However, in the Darwin operating
961system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36
962(avoiding the use of lower case letters) is used instead, because the message
963id is used to construct file names, and the names of files in those systems are
068aaea8 964not always case-sensitive.
168e428f 965
9b371988 966.cindex "pid (process id)" "re-use of"
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967The detail of the contents of the message id have changed as Exim has evolved.
968Earlier versions relied on the operating system not re-using a process id (pid)
969within one second. On modern operating systems, this assumption can no longer
970be made, so the algorithm had to be changed. To retain backward compatibility,
971the format of the message id was retained, which is why the following rules are
972somewhat eccentric:
973
9b371988
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974.ilist
975The first six characters of the message id are the time at which the message
168e428f
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976started to be received, to a granularity of one second. That is, this field
977contains the number of seconds since the start of the epoch (the normal Unix
978way of representing the date and time of day).
9b371988
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979.next
980After the first hyphen, the next six characters are the id of the process that
168e428f 981received the message.
9b371988
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982.next
983There are two different possibilities for the final two characters:
984.olist
0a4e3112 985.oindex "&%localhost_number%&"
9b371988 986If &%localhost_number%& is not set, this value is the fractional part of the
168e428f
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987time of reception, normally in units of 1/2000 of a second, but for systems
988that must use base 36 instead of base 62 (because of case-insensitive file
989systems), the units are 1/1000 of a second.
9b371988
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990.next
991If &%localhost_number%& is set, it is multiplied by 200 (100) and added to
168e428f
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992the fractional part of the time, which in this case is in units of 1/200
993(1/100) of a second.
9b371988
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994.endlist
995.endlist
168e428f
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996
997After a message has been received, Exim waits for the clock to tick at the
998appropriate resolution before proceeding, so that if another message is
999received by the same process, or by another process with the same (re-used)
1000pid, it is guaranteed that the time will be different. In most cases, the clock
1001will already have ticked while the message was being received.
1002
1003
f89d2485 1004.section "Receiving mail" "SECID13"
9b371988
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1005.cindex "receiving mail"
1006.cindex "message" "reception"
068aaea8
PH
1007The only way Exim can receive mail from another host is using SMTP over
1008TCP/IP, in which case the sender and recipient addresses are transferred using
168e428f
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1009SMTP commands. However, from a locally running process (such as a user's MUA),
1010there are several possibilities:
1011
9b371988
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1012.ilist
1013If the process runs Exim with the &%-bm%& option, the message is read
168e428f 1014non-interactively (usually via a pipe), with the recipients taken from the
9b371988
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1015command line, or from the body of the message if &%-t%& is also used.
1016.next
1017If the process runs Exim with the &%-bS%& option, the message is also read
168e428f
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1018non-interactively, but in this case the recipients are listed at the start of
1019the message in a series of SMTP RCPT commands, terminated by a DATA
9b371988 1020command. This is so-called &"batch SMTP"& format,
168e428f
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1021but it isn't really SMTP. The SMTP commands are just another way of passing
1022envelope addresses in a non-interactive submission.
9b371988
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1023.next
1024If the process runs Exim with the &%-bs%& option, the message is read
168e428f
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1025interactively, using the SMTP protocol. A two-way pipe is normally used for
1026passing data between the local process and the Exim process.
9b371988 1027This is &"real"& SMTP and is handled in the same way as SMTP over TCP/IP. For
168e428f 1028example, the ACLs for SMTP commands are used for this form of submission.
9b371988
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1029.next
1030A local process may also make a TCP/IP call to the host's loopback address
168e428f
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1031(127.0.0.1) or any other of its IP addresses. When receiving messages, Exim
1032does not treat the loopback address specially. It treats all such connections
1033in the same way as connections from other hosts.
9b371988 1034.endlist
168e428f
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1035
1036
f89d2485 1037.cindex "message sender, constructed by Exim"
9b371988 1038.cindex "sender" "constructed by Exim"
168e428f
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1039In the three cases that do not involve TCP/IP, the sender address is
1040constructed from the login name of the user that called Exim and a default
9b371988 1041qualification domain (which can be set by the &%qualify_domain%& configuration
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1042option). For local or batch SMTP, a sender address that is passed using the
1043SMTP MAIL command is ignored. However, the system administrator may allow
9b371988 1044certain users (&"trusted users"&) to specify a different sender address
168e428f 1045unconditionally, or all users to specify certain forms of different sender
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1046address. The &%-f%& option or the SMTP MAIL command is used to specify these
1047different addresses. See section &<<SECTtrustedadmin>>& for details of trusted
1048users, and the &%untrusted_set_sender%& option for a way of allowing untrusted
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1049users to change sender addresses.
1050
1051Messages received by either of the non-interactive mechanisms are subject to
1052checking by the non-SMTP ACL, if one is defined. Messages received using SMTP
1053(either over TCP/IP, or interacting with a local process) can be checked by a
1054number of ACLs that operate at different times during the SMTP session. Either
1055individual recipients, or the entire message, can be rejected if local policy
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1056requirements are not met. The &[local_scan()]& function (see chapter
1057&<<CHAPlocalscan>>&) is run for all incoming messages.
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1058
1059Exim can be configured not to start a delivery process when a message is
1060received; this can be unconditional, or depend on the number of incoming SMTP
1061connections or the system load. In these situations, new messages wait on the
1062queue until a queue runner process picks them up. However, in standard
1063configurations under normal conditions, delivery is started as soon as a
1064message is received.
1065
1066
1067
1068
1069
f89d2485 1070.section "Handling an incoming message" "SECID14"
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1071.cindex "spool directory" "files that hold a message"
1072.cindex "file" "how a message is held"
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1073When Exim accepts a message, it writes two files in its spool directory. The
1074first contains the envelope information, the current status of the message, and
1075the header lines, and the second contains the body of the message. The names of
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1076the two spool files consist of the message id, followed by &`-H`& for the
1077file containing the envelope and header, and &`-D`& for the data file.
168e428f 1078
9b371988 1079.cindex "spool directory" "&_input_& sub-directory"
168e428f 1080By default all these message files are held in a single directory called
9b371988 1081&_input_& inside the general Exim spool directory. Some operating systems do
c0712871 1082not perform very well if the number of files in a directory gets large; to
9b371988 1083improve performance in such cases, the &%split_spool_directory%& option can be
168e428f 1084used. This causes Exim to split up the input files into 62 sub-directories
db9452a9 1085whose names are single letters or digits. When this is done, the queue is
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1086processed one sub-directory at a time instead of all at once, which can improve
1087overall performance even when there are not enough files in each directory to
db9452a9 1088affect file system performance.
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1089
1090The envelope information consists of the address of the message's sender and
1091the addresses of the recipients. This information is entirely separate from
1092any addresses contained in the header lines. The status of the message includes
1093a list of recipients who have already received the message. The format of the
9b371988 1094first spool file is described in chapter &<<CHAPspool>>&.
168e428f 1095
9b371988 1096.cindex "rewriting" "addresses"
168e428f 1097Address rewriting that is specified in the rewrite section of the configuration
9b371988 1098(see chapter &<<CHAPrewrite>>&) is done once and for all on incoming addresses,
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1099both in the header lines and the envelope, at the time the message is accepted.
1100If during the course of delivery additional addresses are generated (for
1101example, via aliasing), these new addresses are rewritten as soon as they are
1102generated. At the time a message is actually delivered (transported) further
1103rewriting can take place; because this is a transport option, it can be
1104different for different forms of delivery. It is also possible to specify the
1105addition or removal of certain header lines at the time the message is
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1106delivered (see chapters &<<CHAProutergeneric>>& and
1107&<<CHAPtransportgeneric>>&).
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1108
1109
1110
f89d2485 1111.section "Life of a message" "SECID15"
9b371988
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1112.cindex "message" "life of"
1113.cindex "message" "frozen"
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1114A message remains in the spool directory until it is completely delivered to
1115its recipients or to an error address, or until it is deleted by an
1116administrator or by the user who originally created it. In cases when delivery
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1117cannot proceed &-- for example, when a message can neither be delivered to its
1118recipients nor returned to its sender, the message is marked &"frozen"& on the
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1119spool, and no more deliveries are attempted.
1120
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1121.cindex "frozen messages" "thawing"
1122.cindex "message" "thawing frozen"
1123An administrator can &"thaw"& such messages when the problem has been
1124corrected, and can also freeze individual messages by hand if necessary. In
1125addition, an administrator can force a delivery error, causing a bounce message
1126to be sent.
1127
0a4e3112
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1128.oindex "&%timeout_frozen_after%&"
1129.oindex "&%ignore_bounce_errors_after%&"
9b371988
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1130There are options called &%ignore_bounce_errors_after%& and
1131&%timeout_frozen_after%&, which discard frozen messages after a certain time.
068aaea8 1132The first applies only to frozen bounces, the second to any frozen messages.
168e428f 1133
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1134.cindex "message" "log file for"
1135.cindex "log" "file for each message"
168e428f 1136While Exim is working on a message, it writes information about each delivery
068aaea8 1137attempt to its main log file. This includes successful, unsuccessful, and
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1138delayed deliveries for each recipient (see chapter &<<CHAPlog>>&). The log
1139lines are also written to a separate &'message log'& file for each message.
1140These logs are solely for the benefit of the administrator, and are normally
1141deleted along with the spool files when processing of a message is complete.
168e428f 1142The use of individual message logs can be disabled by setting
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1143&%no_message_logs%&; this might give an improvement in performance on very busy
1144systems.
168e428f 1145
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1146.cindex "journal file"
1147.cindex "file" "journal"
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1148All the information Exim itself needs to set up a delivery is kept in the first
1149spool file, along with the header lines. When a successful delivery occurs, the
1150address is immediately written at the end of a journal file, whose name is the
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1151message id followed by &`-J`&. At the end of a delivery run, if there are some
1152addresses left to be tried again later, the first spool file (the &`-H`& file)
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1153is updated to indicate which these are, and the journal file is then deleted.
1154Updating the spool file is done by writing a new file and renaming it, to
1155minimize the possibility of data loss.
1156
1157Should the system or the program crash after a successful delivery but before
1158the spool file has been updated, the journal is left lying around. The next
1159time Exim attempts to deliver the message, it reads the journal file and
1160updates the spool file before proceeding. This minimizes the chances of double
1161deliveries caused by crashes.
1162
1163
1164
9b371988
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1165.section "Processing an address for delivery" "SECTprocaddress"
1166.cindex "drivers" "definition of"
1167.cindex "router" "definition of"
1168.cindex "transport" "definition of"
1169The main delivery processing elements of Exim are called &'routers'& and
1170&'transports'&, and collectively these are known as &'drivers'&. Code for a
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1171number of them is provided in the source distribution, and compile-time options
1172specify which ones are included in the binary. Run time options specify which
1173ones are actually used for delivering messages.
1174
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1175.cindex "drivers" "instance definition"
1176Each driver that is specified in the run time configuration is an &'instance'&
168e428f 1177of that particular driver type. Multiple instances are allowed; for example,
9b371988 1178you can set up several different &(smtp)& transports, each with different
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1179option values that might specify different ports or different timeouts. Each
1180instance has its own identifying name. In what follows we will normally use the
1181instance name when discussing one particular instance (that is, one specific
1182configuration of the driver), and the generic driver name when discussing
1183the driver's features in general.
1184
9b371988 1185A &'router'& is a driver that operates on an address, either determining how
068aaea8 1186its delivery should happen, by assigning it to a specific transport, or
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1187converting the address into one or more new addresses (for example, via an
1188alias file). A router may also explicitly choose to fail an address, causing it
1189to be bounced.
1190
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1191A &'transport'& is a driver that transmits a copy of the message from Exim's
1192spool to some destination. There are two kinds of transport: for a &'local'&
168e428f 1193transport, the destination is a file or a pipe on the local host, whereas for a
9b371988 1194&'remote'& transport the destination is some other host. A message is passed
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1195to a specific transport as a result of successful routing. If a message has
1196several recipients, it may be passed to a number of different transports.
1197
9b371988 1198.cindex "preconditions" "definition of"
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1199An address is processed by passing it to each configured router instance in
1200turn, subject to certain preconditions, until a router accepts the address or
1201specifies that it should be bounced. We will describe this process in more
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1202detail shortly. First, as a simple example, we consider how each recipient
1203address in a message is processed in a small configuration of three routers.
168e428f 1204
068aaea8 1205To make this a more concrete example, it is described in terms of some actual
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1206routers, but remember, this is only an example. You can configure Exim's
1207routers in many different ways, and there may be any number of routers in a
1208configuration.
1209
1210The first router that is specified in a configuration is often one that handles
1211addresses in domains that are not recognized specially by the local host. These
1212are typically addresses for arbitrary domains on the Internet. A precondition
1213is set up which looks for the special domains known to the host (for example,
9b371988 1214its own domain name), and the router is run for addresses that do &'not'&
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1215match. Typically, this is a router that looks up domains in the DNS in order to
1216find the hosts to which this address routes. If it succeeds, the address is
068aaea8 1217assigned to a suitable SMTP transport; if it does not succeed, the router is
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1218configured to fail the address.
1219
068aaea8 1220The second router is reached only when the domain is recognized as one that
9b371988 1221&"belongs"& to the local host. This router does redirection &-- also known as
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1222aliasing and forwarding. When it generates one or more new addresses from the
1223original, each of them is routed independently from the start. Otherwise, the
1224router may cause an address to fail, or it may simply decline to handle the
1225address, in which case the address is passed to the next router.
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1226
1227The final router in many configurations is one that checks to see if the
1228address belongs to a local mailbox. The precondition may involve a check to
1229see if the local part is the name of a login account, or it may look up the
1230local part in a file or a database. If its preconditions are not met, or if
1231the router declines, we have reached the end of the routers. When this happens,
1232the address is bounced.
1233
1234
1235
f89d2485 1236.section "Processing an address for verification" "SECID16"
9b371988
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1237.cindex "router" "for verification"
1238.cindex "verifying address" "overview"
168e428f 1239As well as being used to decide how to deliver to an address, Exim's routers
9b371988 1240are also used for &'address verification'&. Verification can be requested as
168e428f 1241one of the checks to be performed in an ACL for incoming messages, on both
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1242sender and recipient addresses, and it can be tested using the &%-bv%& and
1243&%-bvs%& command line options.
168e428f 1244
9b371988 1245When an address is being verified, the routers are run in &"verify mode"&. This
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1246does not affect the way the routers work, but it is a state that can be
1247detected. By this means, a router can be skipped or made to behave differently
1248when verifying. A common example is a configuration in which the first router
1249sends all messages to a message-scanning program, unless they have been
1250previously scanned. Thus, the first router accepts all addresses without any
9b371988 1251checking, making it useless for verifying. Normally, the &%no_verify%& option
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1252would be set for such a router, causing it to be skipped in verify mode.
1253
1254
1255
1256
9b371988
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1257.section "Running an individual router" "SECTrunindrou"
1258.cindex "router" "running details"
1259.cindex "preconditions" "checking"
1260.cindex "router" "result of running"
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1261As explained in the example above, a number of preconditions are checked before
1262running a router. If any are not met, the router is skipped, and the address is
9b371988 1263passed to the next router. When all the preconditions on a router &'are'& met,
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1264the router is run. What happens next depends on the outcome, which is one of
1265the following:
1266
9b371988
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1267.ilist
1268&'accept'&: The router accepts the address, and either assigns it to a
1269transport, or generates one or more &"child"& addresses. Processing the
1270original address ceases,
0a4e3112 1271.oindex "&%unseen%&"
9b371988 1272unless the &%unseen%& option is set on the router. This option
168e428f 1273can be used to set up multiple deliveries with different routing (for example,
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1274for keeping archive copies of messages). When &%unseen%& is set, the address is
1275passed to the next router. Normally, however, an &'accept'& return marks the
168e428f 1276end of routing.
9b371988 1277
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1278Any child addresses generated by the router are processed independently,
1279starting with the first router by default. It is possible to change this by
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1280setting the &%redirect_router%& option to specify which router to start at for
1281child addresses. Unlike &%pass_router%& (see below) the router specified by
1282&%redirect_router%& may be anywhere in the router configuration.
1283.next
1284&'pass'&: The router recognizes the address, but cannot handle it itself. It
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1285requests that the address be passed to another router. By default the address
1286is passed to the next router, but this can be changed by setting the
9b371988 1287&%pass_router%& option. However, (unlike &%redirect_router%&) the named router
168e428f 1288must be below the current router (to avoid loops).
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1289.next
1290&'decline'&: The router declines to accept the address because it does not
168e428f 1291recognize it at all. By default, the address is passed to the next router, but
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1292this can be prevented by setting the &%no_more%& option. When &%no_more%& is
1293set, all the remaining routers are skipped. In effect, &%no_more%& converts
1294&'decline'& into &'fail'&.
1295.next
1296&'fail'&: The router determines that the address should fail, and queues it for
168e428f 1297the generation of a bounce message. There is no further processing of the
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1298original address unless &%unseen%& is set on the router.
1299.next
1300&'defer'&: The router cannot handle the address at the present time. (A
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1301database may be offline, or a DNS lookup may have timed out.) No further
1302processing of the address happens in this delivery attempt. It is tried again
1303next time the message is considered for delivery.
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1304.next
1305&'error'&: There is some error in the router (for example, a syntax error in
168e428f 1306its configuration). The action is as for defer.
9b371988 1307.endlist
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1308
1309If an address reaches the end of the routers without having been accepted by
068aaea8 1310any of them, it is bounced as unrouteable. The default error message in this
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1311situation is &"unrouteable address"&, but you can set your own message by
1312making use of the &%cannot_route_message%& option. This can be set for any
1313router; the value from the last router that &"saw"& the address is used.
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1314
1315Sometimes while routing you want to fail a delivery when some conditions are
1316met but others are not, instead of passing the address on for further routing.
1317You can do this by having a second router that explicitly fails the delivery
9b371988 1318when the relevant conditions are met. The &(redirect)& router has a &"fail"&
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1319facility for this purpose.
1320
1321
f89d2485 1322.section "Duplicate addresses" "SECID17"
9b371988 1323.cindex "case of local parts"
f89d2485 1324.cindex "address duplicate, discarding"
db9452a9 1325.cindex "duplicate addresses"
068aaea8
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1326Once routing is complete, Exim scans the addresses that are assigned to local
1327and remote transports, and discards any duplicates that it finds. During this
3cb1b51e 1328check, local parts are treated as case-sensitive. This happens only when
db9452a9 1329actually delivering a message; when testing routers with &%-bt%&, all the
3cb1b51e 1330routed addresses are shown.
db9452a9 1331
068aaea8 1332
168e428f 1333
9b371988 1334.section "Router preconditions" "SECTrouprecon"
f89d2485 1335.cindex "router" "preconditions, order of processing"
9b371988 1336.cindex "preconditions" "order of processing"
168e428f
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1337The preconditions that are tested for each router are listed below, in the
1338order in which they are tested. The individual configuration options are
9b371988 1339described in more detail in chapter &<<CHAProutergeneric>>&.
168e428f 1340
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1341.ilist
1342The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
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1343the local parts handled by the router may or must have certain prefixes and/or
1344suffixes. If a mandatory affix (prefix or suffix) is not present, the router is
1345skipped. These conditions are tested first. When an affix is present, it is
1346removed from the local part before further processing, including the evaluation
1347of any other conditions.
9b371988
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1348.next
1349Routers can be designated for use only when not verifying an address, that is,
168e428f 1350only when routing it for delivery (or testing its delivery routing). If the
9b371988 1351&%verify%& option is set false, the router is skipped when Exim is verifying an
168e428f 1352address.
9b371988
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1353Setting the &%verify%& option actually sets two options, &%verify_sender%& and
1354&%verify_recipient%&, which independently control the use of the router for
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1355sender and recipient verification. You can set these options directly if
1356you want a router to be used for only one type of verification.
9b371988
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1357.next
1358If the &%address_test%& option is set false, the router is skipped when Exim is
1359run with the &%-bt%& option to test an address routing. This can be helpful
1360when the first router sends all new messages to a scanner of some sort; it
1361makes it possible to use &%-bt%& to test subsequent delivery routing without
1362having to simulate the effect of the scanner.
1363.next
1364Routers can be designated for use only when verifying an address, as
1365opposed to routing it for delivery. The &%verify_only%& option controls this.
1366.next
1367Individual routers can be explicitly skipped when running the routers to
1368check an address given in the SMTP EXPN command (see the &%expn%& option).
1369.next
1370If the &%domains%& option is set, the domain of the address must be in the set
068aaea8 1371of domains that it defines.
9b371988 1372.next
f89d2485
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1373.vindex "&$local_part_prefix$&"
1374.vindex "&$local_part$&"
1375.vindex "&$local_part_suffix$&"
9b371988
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1376If the &%local_parts%& option is set, the local part of the address must be in
1377the set of local parts that it defines. If &%local_part_prefix%& or
1378&%local_part_suffix%& is in use, the prefix or suffix is removed from the local
168e428f 1379part before this check. If you want to do precondition tests on local parts
9b371988
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1380that include affixes, you can do so by using a &%condition%& option (see below)
1381that uses the variables &$local_part$&, &$local_part_prefix$&, and
1382&$local_part_suffix$& as necessary.
1383.next
f89d2485
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1384.vindex "&$local_user_uid$&"
1385.vindex "&$local_user_gid$&"
1386.vindex "&$home$&"
9b371988 1387If the &%check_local_user%& option is set, the local part must be the name of
068aaea8 1388an account on the local host. If this check succeeds, the uid and gid of the
9b371988
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1389local user are placed in &$local_user_uid$& and &$local_user_gid$& and the
1390user's home directory is placed in &$home$&; these values can be used in the
1391remaining preconditions.
1392.next
1393If the &%router_home_directory%& option is set, it is expanded at this point,
1394because it overrides the value of &$home$&. If this expansion were left till
1395later, the value of &$home$& as set by &%check_local_user%& would be used in
1396subsequent tests. Having two different values of &$home$& in the same router
168e428f 1397could lead to confusion.
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1398.next
1399If the &%senders%& option is set, the envelope sender address must be in the
1400set of addresses that it defines.
1401.next
1402If the &%require_files%& option is set, the existence or non-existence of
168e428f 1403specified files is tested.
9b371988
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1404.next
1405.cindex "customizing" "precondition"
1406If the &%condition%& option is set, it is evaluated and tested. This option
1407uses an expanded string to allow you to set up your own custom preconditions.
1408Expanded strings are described in chapter &<<CHAPexpand>>&.
1409.endlist
168e428f 1410
168e428f 1411
9b371988
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1412Note that &%require_files%& comes near the end of the list, so you cannot use
1413it to check for the existence of a file in which to lookup up a domain, local
168e428f 1414part, or sender. However, as these options are all expanded, you can use the
9b371988
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1415&%exists%& expansion condition to make such tests within each condition. The
1416&%require_files%& option is intended for checking files that the router may be
168e428f 1417going to use internally, or which are needed by a specific transport (for
9b371988 1418example, &_.procmailrc_&).
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1419
1420
1421
f89d2485 1422.section "Delivery in detail" "SECID18"
9b371988 1423.cindex "delivery" "in detail"
168e428f
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1424When a message is to be delivered, the sequence of events is as follows:
1425
9b371988
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1426.ilist
1427If a system-wide filter file is specified, the message is passed to it. The
168e428f
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1428filter may add recipients to the message, replace the recipients, discard the
1429message, cause a new message to be generated, or cause the message delivery to
1430fail. The format of the system filter file is the same as for Exim user filter
9b371988
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1431files, described in the separate document entitled &'Exim's interfaces to mail
1432filtering'&.
1433.cindex "Sieve filter" "not available for system filter"
1434(&*Note*&: Sieve cannot be used for system filter files.)
1435
1436Some additional features are available in system filters &-- see chapter
1437&<<CHAPsystemfilter>>& for details. Note that a message is passed to the system
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1438filter only once per delivery attempt, however many recipients it has. However,
1439if there are several delivery attempts because one or more addresses could not
1440be immediately delivered, the system filter is run each time. The filter
9b371988 1441condition &%first_delivery%& can be used to detect the first run of the system
168e428f 1442filter.
9b371988
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1443.next
1444Each recipient address is offered to each configured router in turn, subject to
1445its preconditions, until one is able to handle it. If no router can handle the
1446address, that is, if they all decline, the address is failed. Because routers
1447can be targeted at particular domains, several locally handled domains can be
1448processed entirely independently of each other.
1449.next
1450.cindex "routing" "loops in"
1451.cindex "loop" "while routing"
1452A router that accepts an address may assign it to a local or a remote
1453transport. However, the transport is not run at this time. Instead, the address
1454is placed on a list for the particular transport, which will be run later.
068aaea8
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1455Alternatively, the router may generate one or more new addresses (typically
1456from alias, forward, or filter files). New addresses are fed back into this
1457process from the top, but in order to avoid loops, a router ignores any address
1458which has an identically-named ancestor that was processed by itself.
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1459.next
1460When all the routing has been done, addresses that have been successfully
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1461handled are passed to their assigned transports. When local transports are
1462doing real local deliveries, they handle only one address at a time, but if a
1463local transport is being used as a pseudo-remote transport (for example, to
1464collect batched SMTP messages for transmission by some other means) multiple
1465addresses can be handled. Remote transports can always handle more than one
1466address at a time, but can be configured not to do so, or to restrict multiple
1467addresses to the same domain.
9b371988
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1468.next
1469Each local delivery to a file or a pipe runs in a separate process under a
168e428f
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1470non-privileged uid, and these deliveries are run one at a time. Remote
1471deliveries also run in separate processes, normally under a uid that is private
9b371988 1472to Exim (&"the Exim user"&), but in this case, several remote deliveries can be
168e428f 1473run in parallel. The maximum number of simultaneous remote deliveries for any
9b371988 1474one message is set by the &%remote_max_parallel%& option.
168e428f
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1475The order in which deliveries are done is not defined, except that all local
1476deliveries happen before any remote deliveries.
9b371988
PH
1477.next
1478.cindex "queue runner"
168e428f
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1479When it encounters a local delivery during a queue run, Exim checks its retry
1480database to see if there has been a previous temporary delivery failure for the
1481address before running the local transport. If there was a previous failure,
1482Exim does not attempt a new delivery until the retry time for the address is
1483reached. However, this happens only for delivery attempts that are part of a
1484queue run. Local deliveries are always attempted when delivery immediately
1485follows message reception, even if retry times are set for them. This makes for
1486better behaviour if one particular message is causing problems (for example,
1487causing quota overflow, or provoking an error in a filter file).
9b371988
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1488.next
1489.cindex "delivery" "retry in remote transports"
168e428f
PH
1490Remote transports do their own retry handling, since an address may be
1491deliverable to one of a number of hosts, each of which may have a different
1492retry time. If there have been previous temporary failures and no host has
1493reached its retry time, no delivery is attempted, whether in a queue run or
9b371988
PH
1494not. See chapter &<<CHAPretry>>& for details of retry strategies.
1495.next
1496If there were any permanent errors, a bounce message is returned to an
168e428f
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1497appropriate address (the sender in the common case), with details of the error
1498for each failing address. Exim can be configured to send copies of bounce
1499messages to other addresses.
9b371988
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1500.next
1501.cindex "delivery" "deferral"
168e428f
PH
1502If one or more addresses suffered a temporary failure, the message is left on
1503the queue, to be tried again later. Delivery of these addresses is said to be
9b371988
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1504&'deferred'&.
1505.next
1506When all the recipient addresses have either been delivered or bounced,
168e428f
PH
1507handling of the message is complete. The spool files and message log are
1508deleted, though the message log can optionally be preserved if required.
9b371988 1509.endlist
168e428f
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1510
1511
1512
1513
f89d2485 1514.section "Retry mechanism" "SECID19"
9b371988
PH
1515.cindex "delivery" "retry mechanism"
1516.cindex "retry" "description of mechanism"
1517.cindex "queue runner"
168e428f
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1518Exim's mechanism for retrying messages that fail to get delivered at the first
1519attempt is the queue runner process. You must either run an Exim daemon that
9b371988
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1520uses the &%-q%& option with a time interval to start queue runners at regular
1521intervals, or use some other means (such as &'cron'&) to start them. If you do
168e428f
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1522not arrange for queue runners to be run, messages that fail temporarily at the
1523first attempt will remain on your queue for ever. A queue runner process works
068aaea8 1524its way through the queue, one message at a time, trying each delivery that has
168e428f
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1525passed its retry time.
1526You can run several queue runners at once.
1527
1528Exim uses a set of configured rules to determine when next to retry the failing
9b371988
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1529address (see chapter &<<CHAPretry>>&). These rules also specify when Exim
1530should give up trying to deliver to the address, at which point it generates a
1531bounce message. If no retry rules are set for a particular host, address, and
1532error combination, no retries are attempted, and temporary errors are treated
1533as permanent.
168e428f
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1534
1535
1536
f89d2485 1537.section "Temporary delivery failure" "SECID20"
9b371988 1538.cindex "delivery" "temporary failure"
168e428f
PH
1539There are many reasons why a message may not be immediately deliverable to a
1540particular address. Failure to connect to a remote machine (because it, or the
1541connection to it, is down) is one of the most common. Temporary failures may be
1542detected during routing as well as during the transport stage of delivery.
1543Local deliveries may be delayed if NFS files are unavailable, or if a mailbox
1544is on a file system where the user is over quota. Exim can be configured to
1545impose its own quotas on local mailboxes; where system quotas are set they will
1546also apply.
1547
1548If a host is unreachable for a period of time, a number of messages may be
1549waiting for it by the time it recovers, and sending them in a single SMTP
1550connection is clearly beneficial. Whenever a delivery to a remote host is
1551deferred,
1552
9b371988 1553.cindex "hints database"
168e428f
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1554Exim makes a note in its hints database, and whenever a successful
1555SMTP delivery has happened, it looks to see if any other messages are waiting
1556for the same host. If any are found, they are sent over the same SMTP
1557connection, subject to a configuration limit as to the maximum number in any
1558one connection.
1559
1560
1561
1562
f89d2485 1563.section "Permanent delivery failure" "SECID21"
9b371988
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1564.cindex "delivery" "permanent failure"
1565.cindex "bounce message" "when generated"
168e428f
PH
1566When a message cannot be delivered to some or all of its intended recipients, a
1567bounce message is generated. Temporary delivery failures turn into permanent
1568errors when their timeout expires. All the addresses that fail in a given
1569delivery attempt are listed in a single message. If the original message has
1570many recipients, it is possible for some addresses to fail in one delivery
1571attempt and others to fail subsequently, giving rise to more than one bounce
1572message. The wording of bounce messages can be customized by the administrator.
9b371988 1573See chapter &<<CHAPemsgcust>>& for details.
168e428f 1574
9b371988
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1575.cindex "&'X-Failed-Recipients:'& header line"
1576Bounce messages contain an &'X-Failed-Recipients:'& header line that lists the
168e428f
PH
1577failed addresses, for the benefit of programs that try to analyse such messages
1578automatically.
1579
9b371988 1580.cindex "bounce message" "recipient of"
168e428f
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1581A bounce message is normally sent to the sender of the original message, as
1582obtained from the message's envelope. For incoming SMTP messages, this is the
9b371988
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1583address given in the MAIL command. However, when an address is expanded via a
1584forward or alias file, an alternative address can be specified for delivery
1585failures of the generated addresses. For a mailing list expansion (see section
1586&<<SECTmailinglists>>&) it is common to direct bounce messages to the manager
1587of the list.
168e428f
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1588
1589
1590
f89d2485 1591.section "Failures to deliver bounce messages" "SECID22"
9b371988 1592.cindex "bounce message" "failure to deliver"
168e428f
PH
1593If a bounce message (either locally generated or received from a remote host)
1594itself suffers a permanent delivery failure, the message is left on the queue,
1595but it is frozen, awaiting the attention of an administrator. There are options
068aaea8 1596that can be used to make Exim discard such failed messages, or to keep them
9b371988
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1597for only a short time (see &%timeout_frozen_after%& and
1598&%ignore_bounce_errors_after%&).
168e428f
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1599
1600
1601
1602
1603
9b371988
PH
1604. ////////////////////////////////////////////////////////////////////////////
1605. ////////////////////////////////////////////////////////////////////////////
168e428f 1606
f89d2485 1607.chapter "Building and installing Exim" "CHID3"
4f578862 1608.scindex IIDbuex "building Exim"
168e428f 1609
f89d2485
PH
1610.section "Unpacking" "SECID23"
1611Exim is distributed as a gzipped or bzipped tar file which, when unpacked,
168e428f 1612creates a directory with the name of the current release (for example,
9b371988
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1613&_exim-&version;_&) into which the following files are placed:
1614
1615.table2 140pt
f89d2485
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1616.irow &_ACKNOWLEDGMENTS_& "contains some acknowledgments"
1617.irow &_CHANGES_& "contains a reference to where changes are &&&
1618 documented"
1619.irow &_LICENCE_& "the GNU General Public Licence"
1620.irow &_Makefile_& "top-level make file"
1621.irow &_NOTICE_& "conditions for the use of Exim"
1622.irow &_README_& "list of files, directories and simple build &&&
1623 instructions"
9b371988
PH
1624.endtable
1625
1626Other files whose names begin with &_README_& may also be present. The
168e428f
PH
1627following subdirectories are created:
1628
9b371988 1629.table2 140pt
f89d2485
PH
1630.irow &_Local_& "an empty directory for local configuration files"
1631.irow &_OS_& "OS-specific files"
1632.irow &_doc_& "documentation files"
1633.irow &_exim_monitor_& "source files for the Exim monitor"
1634.irow &_scripts_& "scripts used in the build process"
1635.irow &_src_& "remaining source files"
1636.irow &_util_& "independent utilities"
9b371988
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1637.endtable
1638
1639The main utility programs are contained in the &_src_& directory, and are built
1640with the Exim binary. The &_util_& directory contains a few optional scripts
168e428f
PH
1641that may be useful to some sites.
1642
1643
f89d2485 1644.section "Multiple machine architectures and operating systems" "SECID24"
9b371988 1645.cindex "building Exim" "multiple OS/architectures"
168e428f
PH
1646The building process for Exim is arranged to make it easy to build binaries for
1647a number of different architectures and operating systems from the same set of
9b371988
PH
1648source files. Compilation does not take place in the &_src_& directory.
1649Instead, a &'build directory'& is created for each architecture and operating
1650system.
1651.cindex "symbolic link" "to build directory"
168e428f 1652Symbolic links to the sources are installed in this directory, which is where
9b371988
PH
1653the actual building takes place. In most cases, Exim can discover the machine
1654architecture and operating system for itself, but the defaults can be
1655overridden if necessary.
168e428f 1656
168e428f 1657
8473d4ee 1658.section "PCRE library" "SECTpcre"
210f147e
NM
1659.cindex "PCRE library"
1660Exim no longer has an embedded PCRE library as the vast majority of
1661modern systems include PCRE as a system library, although you may need
1662to install the PCRE or PCRE development package for your operating
1663system. If your system has a normal PCRE installation the Exim build
1664process will need no further configuration. If the library or the
1665headers are in an unusual location you will need to set the PCRE_LIBS
1666and INCLUDE directives appropriately. If your operating system has no
1667PCRE support then you will need to obtain and build the current PCRE
1668from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/).
1669
9b371988
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1670.section "DBM libraries" "SECTdb"
1671.cindex "DBM libraries" "discussion of"
1672.cindex "hints database" "DBM files used for"
168e428f
PH
1673Even if you do not use any DBM files in your configuration, Exim still needs a
1674DBM library in order to operate, because it uses indexed files for its hints
1675databases. Unfortunately, there are a number of DBM libraries in existence, and
1676different operating systems often have different ones installed.
1677
9b371988 1678.cindex "Solaris" "DBM library for"
f89d2485
PH
1679.cindex "IRIX, DBM library for"
1680.cindex "BSD, DBM library for"
1681.cindex "Linux, DBM library for"
168e428f
PH
1682If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1683Linux distribution, the DBM configuration should happen automatically, and you
1684may be able to ignore this section. Otherwise, you may have to learn more than
1685you would like about DBM libraries from what follows.
1686
9b371988 1687.cindex "&'ndbm'& DBM library"
168e428f 1688Licensed versions of Unix normally contain a library of DBM functions operating
9b371988 1689via the &'ndbm'& interface, and this is what Exim expects by default. Free
168e428f
PH
1690versions of Unix seem to vary in what they contain as standard. In particular,
1691some early versions of Linux have no default DBM library, and different
1692distributors have chosen to bundle different libraries with their packaged
f89d2485 1693versions. However, the more recent releases seem to have standardized on the
168e428f
PH
1694Berkeley DB library.
1695
1696Different DBM libraries have different conventions for naming the files they
9b371988 1697use. When a program opens a file called &_dbmfile_&, there are several
168e428f
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1698possibilities:
1699
9b371988
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1700.olist
1701A traditional &'ndbm'& implementation, such as that supplied as part of
1702Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1703.next
1704.cindex "&'gdbm'& DBM library"
1705The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
168e428f 1706compatibility interface it makes two different hard links to it with names
9b371988 1707&_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
168e428f 1708file name is used unmodified.
9b371988
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1709.next
1710.cindex "Berkeley DB library"
1711The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1712operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1713programmer exactly the same as the traditional &'ndbm'& implementation.
1714.next
1715If the Berkeley package is used in its native mode, it operates on a single
1716file called &_dbmfile_&; the programmer's interface is somewhat different to
1717the traditional &'ndbm'& interface.
1718.next
1719To complicate things further, there are several very different versions of the
168e428f 1720Berkeley DB package. Version 1.85 was stable for a very long time, releases
9b371988
PH
17212.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1722numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
168e428f 1723versions of Berkeley DB can be obtained from
9b371988
PH
1724&url(http://www.sleepycat.com/).
1725.next
1726.cindex "&'tdb'& DBM library"
1727Yet another DBM library, called &'tdb'&, is available from
1728&url(http://download.sourceforge.net/tdb). It has its own interface, and also
1729operates on a single file.
1730.endlist
1731
1732.cindex "USE_DB"
1733.cindex "DBM libraries" "configuration for building"
168e428f
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1734Exim and its utilities can be compiled to use any of these interfaces. In order
1735to use any version of the Berkeley DB package in native mode, you must set
1736USE_DB in an appropriate configuration file (typically
9b371988
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1737&_Local/Makefile_&). For example:
1738.code
1739USE_DB=yes
1740.endd
168e428f
PH
1741Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1742error is diagnosed if you set more than one of these.
1743
1744At the lowest level, the build-time configuration sets none of these options,
1745thereby assuming an interface of type (1). However, some operating system
1746configuration files (for example, those for the BSD operating systems and
1747Linux) assume type (4) by setting USE_DB as their default, and the
1748configuration files for Cygwin set USE_GDBM. Anything you set in
9b371988 1749&_Local/Makefile_&, however, overrides these system defaults.
168e428f
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1750
1751As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1752necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1753in one of these lines:
9b371988
PH
1754.code
1755DBMLIB = -ldb
1756DBMLIB = -ltdb
1757.endd
168e428f
PH
1758Settings like that will work if the DBM library is installed in the standard
1759place. Sometimes it is not, and the library's header file may also not be in
1760the default path. You may need to set INCLUDE to specify where the header
1761file is, and to specify the path to the library more fully in DBMLIB, as in
1762this example:
9b371988
PH
1763.code
1764INCLUDE=-I/usr/local/include/db-4.1
1765DBMLIB=/usr/local/lib/db-4.1/libdb.a
1766.endd
168e428f 1767There is further detailed discussion about the various DBM libraries in the
9b371988 1768file &_doc/dbm.discuss.txt_& in the Exim distribution.
168e428f
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1769
1770
1771
f89d2485 1772.section "Pre-building configuration" "SECID25"
9b371988
PH
1773.cindex "building Exim" "pre-building configuration"
1774.cindex "configuration for building Exim"
1775.cindex "&_Local/Makefile_&"
1776.cindex "&_src/EDITME_&"
168e428f
PH
1777Before building Exim, a local configuration file that specifies options
1778independent of any operating system has to be created with the name
9b371988
PH
1779&_Local/Makefile_&. A template for this file is supplied as the file
1780&_src/EDITME_&, and it contains full descriptions of all the option settings
168e428f
PH
1781therein. These descriptions are therefore not repeated here. If you are
1782building Exim for the first time, the simplest thing to do is to copy
9b371988 1783&_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
168e428f
PH
1784
1785There are three settings that you must supply, because Exim will not build
1786without them. They are the location of the run time configuration file
1787(CONFIGURE_FILE), the directory in which Exim binaries will be installed
1788(BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1789maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1790a colon-separated list of file names; Exim uses the first of them that exists.
1791
1792There are a few other parameters that can be specified either at build time or
1793at run time, to enable the same binary to be used on a number of different
1794machines. However, if the locations of Exim's spool directory and log file
1795directory (if not within the spool directory) are fixed, it is recommended that
9b371988 1796you specify them in &_Local/Makefile_& instead of at run time, so that errors
168e428f
PH
1797detected early in Exim's execution (such as a malformed configuration file) can
1798be logged.
1799
9b371988 1800.cindex "content scanning" "specifying at build time"
068aaea8 1801Exim's interfaces for calling virus and spam scanning software directly from
168e428f
PH
1802access control lists are not compiled by default. If you want to include these
1803facilities, you need to set
9b371988
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1804.code
1805WITH_CONTENT_SCAN=yes
1806.endd
1807in your &_Local/Makefile_&. For details of the facilities themselves, see
1808chapter &<<CHAPexiscan>>&.
168e428f
PH
1809
1810
9b371988 1811.cindex "&_Local/eximon.conf_&"
3cb1b51e 1812.cindex "&_exim_monitor/EDITME_&"
168e428f 1813If you are going to build the Exim monitor, a similar configuration process is
9b371988
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1814required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1815your installation and saved under the name &_Local/eximon.conf_&. If you are
1816happy with the default settings described in &_exim_monitor/EDITME_&,
1817&_Local/eximon.conf_& can be empty, but it must exist.
168e428f
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1818
1819This is all the configuration that is needed in straightforward cases for known
1820operating systems. However, the building process is set up so that it is easy
1821to override options that are set by default or by operating-system-specific
1822configuration files, for example to change the name of the C compiler, which
9b371988
PH
1823defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1824do this.
168e428f
PH
1825
1826
1827
f89d2485 1828.section "Support for iconv()" "SECID26"
9b371988
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1829.cindex "&[iconv()]& support"
1830.cindex "RFC 2047"
168e428f
PH
1831The contents of header lines in messages may be encoded according to the rules
1832described RFC 2047. This makes it possible to transmit characters that are not
1833in the ASCII character set, and to label them as being in a particular
9b371988 1834character set. When Exim is inspecting header lines by means of the &%$h_%&
168e428f
PH
1835mechanism, it decodes them, and translates them into a specified character set
1836(default ISO-8859-1). The translation is possible only if the operating system
9b371988
PH
1837supports the &[iconv()]& function.
1838
1839However, some of the operating systems that supply &[iconv()]& do not support
1840very many conversions. The GNU &%libiconv%& library (available from
1841&url(http://www.gnu.org/software/libiconv/)) can be installed on such
1842systems to remedy this deficiency, as well as on systems that do not supply
1843&[iconv()]& at all. After installing &%libiconv%&, you should add
1844.code
1845HAVE_ICONV=yes
1846.endd
1847to your &_Local/Makefile_& and rebuild Exim.
1848
1849
1850
1851.section "Including TLS/SSL encryption support" "SECTinctlsssl"
1852.cindex "TLS" "including support for TLS"
1853.cindex "encryption" "including support for"
1854.cindex "SUPPORT_TLS"
1855.cindex "OpenSSL" "building Exim with"
1856.cindex "GnuTLS" "building Exim with"
168e428f
PH
1857Exim can be built to support encrypted SMTP connections, using the STARTTLS
1858command as per RFC 2487. It can also support legacy clients that expect to
1859start a TLS session immediately on connection to a non-standard port (see the
9b371988 1860&%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
168e428f
PH
1861line option).
1862
1863If you want to build Exim with TLS support, you must first install either the
1864OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1865implementing SSL.
1866
1867If OpenSSL is installed, you should set
9b371988
PH
1868.code
1869SUPPORT_TLS=yes
1870TLS_LIBS=-lssl -lcrypto
1871.endd
1872in &_Local/Makefile_&. You may also need to specify the locations of the
168e428f 1873OpenSSL library and include files. For example:
9b371988
PH
1874.code
1875SUPPORT_TLS=yes
1876TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1877TLS_INCLUDE=-I/usr/local/openssl/include/
1878.endd
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
168e428f 1894You do not need to set TLS_INCLUDE if the relevant directory is already
9b371988
PH
1895specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1896given in chapter &<<CHAPTLS>>&.
168e428f
PH
1897
1898
1899
1900
f89d2485
PH
1901.section "Use of tcpwrappers" "SECID27"
1902.cindex "tcpwrappers, building Exim to support"
9b371988
PH
1903.cindex "USE_TCP_WRAPPERS"
1904Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1905SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
168e428f 1906alternative to Exim's own checking facilities for installations that are
9b371988
PH
1907already making use of &'tcpwrappers'& for other purposes. To do this, you
1908should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1909&_tcpd.h_& to be available at compile time, and also ensure that the library
1910&_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1911EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1912you might have
1913.code
1914USE_TCP_WRAPPERS=yes
1915CFLAGS=-O -I/usr/local/include
1916EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1917.endd
1918in &_Local/Makefile_&. The name to use in the &'tcpwrappers'& control files is
1919&"exim"&. For example, the line
1920.code
1921exim : LOCAL 192.168.1. .friendly.domain.example
1922.endd
1923in your &_/etc/hosts.allow_& file allows connections from the local host, from
1924the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&.
1925All other connections are denied. Consult the &'tcpwrappers'& documentation for
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1926further details.
1927
1928
1929
f89d2485 1930.section "Including support for IPv6" "SECID28"
9b371988 1931.cindex "IPv6" "including support for"
168e428f 1932Exim contains code for use on systems that have IPv6 support. Setting
9b371988 1933&`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
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1934it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1935where the IPv6 support is not fully integrated into the normal include and
1936library files.
1937
1938Two different types of DNS record for handling IPv6 addresses have been
f89d2485 1939defined. AAAA records (analogous to A records for IPv4) are in use, and are
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1940currently seen as the mainstream. Another record type called A6 was proposed
1941as better than AAAA because it had more flexibility. However, it was felt to be
9b371988 1942over-complex, and its status was reduced to &"experimental"&. It is not known
168e428f 1943if anyone is actually using A6 records. Exim has support for A6 records, but
9b371988 1944this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
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1945support has not been tested for some time.
1946
1947
1948
f89d2485 1949.section "The building process" "SECID29"
9b371988
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1950.cindex "build directory"
1951Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
1952created, run &'make'& at the top level. It determines the architecture and
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1953operating system types, and creates a build directory if one does not exist.
1954For example, on a Sun system running Solaris 8, the directory
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1955&_build-SunOS5-5.8-sparc_& is created.
1956.cindex "symbolic link" "to source files"
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1957Symbolic links to relevant source files are installed in the build directory.
1958
9b371988 1959&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
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1960building process fails if it is set.
1961
9b371988 1962If this is the first time &'make'& has been run, it calls a script that builds
168e428f 1963a make file inside the build directory, using the configuration files from the
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1964&_Local_& directory. The new make file is then passed to another instance of
1965&'make'&. This does the real work, building a number of utility scripts, and
168e428f 1966then compiling and linking the binaries for the Exim monitor (if configured), a
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1967number of utility programs, and finally Exim itself. The command &`make
1968makefile`& can be used to force a rebuild of the make file in the build
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1969directory, should this ever be necessary.
1970
1971If you have problems building Exim, check for any comments there may be in the
9b371988 1972&_README_& file concerning your operating system, and also take a look at the
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1973FAQ, where some common problems are covered.
1974
1975
1976
f89d2485 1977.section 'Output from &"make"&' "SECID283"
9b371988 1978The output produced by the &'make'& process for compile lines is often very
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1979unreadable, because these lines can be very long. For this reason, the normal
1980output is suppressed by default, and instead output similar to that which
1981appears when compiling the 2.6 Linux kernel is generated: just a short line for
1982each module that is being compiled or linked. However, it is still possible to
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1983get the full output, by calling &'make'& like this:
1984.code
1985FULLECHO='' make -e
1986.endd
1987The value of FULLECHO defaults to &"@"&, the flag character that suppresses
1988command reflection in &'make'&. When you ask for the full output, it is
3cb1b51e 1989given in addition to the short output.
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1990
1991
1992
9b371988 1993.section "Overriding build-time options for Exim" "SECToverride"
f89d2485 1994.cindex "build-time options, overriding"
168e428f
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1995The main make file that is created at the beginning of the building process
1996consists of the concatenation of a number of files which set configuration
9b371988 1997values, followed by a fixed set of &'make'& instructions. If a value is set
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1998more than once, the last setting overrides any previous ones. This provides a
1999convenient way of overriding defaults. The files that are concatenated are, in
2000order:
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2001.display
2002&_OS/Makefile-Default_&
2003&_OS/Makefile-_&<&'ostype'&>
2004&_Local/Makefile_&
2005&_Local/Makefile-_&<&'ostype'&>
2006&_Local/Makefile-_&<&'archtype'&>
2007&_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
2008&_OS/Makefile-Base_&
2009.endd
2010.cindex "&_Local/Makefile_&"
2011.cindex "building Exim" "operating system type"
2012.cindex "building Exim" "architecture type"
2013where <&'ostype'&> is the operating system type and <&'archtype'&> is the
2014architecture type. &_Local/Makefile_& is required to exist, and the building
2015process fails if it is absent. The other three &_Local_& files are optional,
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2016and are often not needed.
2017
9b371988
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2018The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
2019called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
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2020the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
2021values are used, thereby providing a means of forcing particular settings.
9b371988 2022Otherwise, the scripts try to get values from the &%uname%& command. If this
168e428f 2023fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
9b371988 2024of &'ad hoc'& transformations are then applied, to produce the standard names
168e428f
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2025that Exim expects. You can run these scripts directly from the shell in order
2026to find out what values are being used on your system.
2027
2028
9b371988 2029&_OS/Makefile-Default_& contains comments about the variables that are set
168e428f
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2030therein. Some (but not all) are mentioned below. If there is something that
2031needs changing, review the contents of this file and the contents of the make
9b371988 2032file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
168e428f
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2033default values are.
2034
2035
9b371988
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2036.cindex "building Exim" "overriding default settings"
2037If you need to change any of the values that are set in &_OS/Makefile-Default_&
2038or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
168e428f 2039need to change the original files. Instead, you should make the changes by
9b371988
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2040putting the new values in an appropriate &_Local_& file. For example,
2041.cindex "Tru64-Unix build-time settings"
168e428f
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2042when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2043formerly DEC-OSF1) operating system, it is necessary to specify that the C
9b371988
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2044compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2045called with the option &%-std1%&, to make it recognize some of the features of
168e428f 2046Standard C that Exim uses. (Most other compilers recognize Standard C by
9b371988 2047default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
168e428f 2048containing the lines
9b371988
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2049.code
2050CC=cc
2051CFLAGS=-std1
2052.endd
168e428f 2053If you are compiling for just one operating system, it may be easier to put
9b371988 2054these lines directly into &_Local/Makefile_&.
168e428f
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2055
2056Keeping all your local configuration settings separate from the distributed
2057files makes it easy to transfer them to new versions of Exim simply by copying
9b371988 2058the contents of the &_Local_& directory.
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2059
2060
9b371988
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2061.cindex "NIS lookup type" "including support for"
2062.cindex "NIS+ lookup type" "including support for"
2063.cindex "LDAP" "including support for"
2064.cindex "lookup" "inclusion in binary"
168e428f
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2065Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2066lookup, but not all systems have these components installed, so the default is
2067not to include the relevant code in the binary. All the different kinds of file
2068and database lookup that Exim supports are implemented as separate code modules
2069which are included only if the relevant compile-time options are set. In the
9b371988
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2070case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2071.code
2072LOOKUP_LDAP=yes
2073LOOKUP_NIS=yes
2074LOOKUP_NISPLUS=yes
2075.endd
168e428f 2076and similar settings apply to the other lookup types. They are all listed in
9b371988 2077&_src/EDITME_&. In many cases the relevant include files and interface
168e428f 2078libraries need to be installed before compiling Exim.
9b371988 2079.cindex "cdb" "including support for"
068aaea8
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2080However, there are some optional lookup types (such as cdb) for which
2081the code is entirely contained within Exim, and no external include
168e428f
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2082files or libraries are required. When a lookup type is not included in the
2083binary, attempts to configure Exim to use it cause run time configuration
2084errors.
2085
9b371988 2086.cindex "Perl" "including support for"
168e428f
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2087Exim can be linked with an embedded Perl interpreter, allowing Perl
2088subroutines to be called during string expansion. To enable this facility,
9b371988
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2089.code
2090EXIM_PERL=perl.o
2091.endd
2092must be defined in &_Local/Makefile_&. Details of this facility are given in
2093chapter &<<CHAPperl>>&.
168e428f 2094
f89d2485 2095.cindex "X11 libraries, location of"
168e428f 2096The location of the X11 libraries is something that varies a lot between
068aaea8 2097operating systems, and there may be different versions of X11 to cope
168e428f
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2098with. Exim itself makes no use of X11, but if you are compiling the Exim
2099monitor, the X11 libraries must be available.
9b371988
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2100The following three variables are set in &_OS/Makefile-Default_&:
2101.code
2102X11=/usr/X11R6
2103XINCLUDE=-I$(X11)/include
2104XLFLAGS=-L$(X11)/lib
2105.endd
168e428f 2106These are overridden in some of the operating-system configuration files. For
9b371988
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2107example, in &_OS/Makefile-SunOS5_& there is
2108.code
2109X11=/usr/openwin
2110XINCLUDE=-I$(X11)/include
2111XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2112.endd
168e428f
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2113If you need to override the default setting for your operating system, place a
2114definition of all three of these variables into your
9b371988 2115&_Local/Makefile-<ostype>_& file.
168e428f 2116
9b371988 2117.cindex "EXTRALIBS"
168e428f
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2118If you need to add any extra libraries to the link steps, these can be put in a
2119variable called EXTRALIBS, which appears in all the link commands, but by
2120default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2121command for linking the main Exim binary, and not for any associated utilities.
2122
9b371988 2123.cindex "DBM libraries" "configuration for building"
168e428f 2124There is also DBMLIB, which appears in the link commands for binaries that
9b371988 2125use DBM functions (see also section &<<SECTdb>>&). Finally, there is
168e428f
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2126EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2127binary, and which can be used, for example, to include additional X11
2128libraries.
2129
9b371988 2130.cindex "configuration file" "editing"
168e428f
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2131The make file copes with rebuilding Exim correctly if any of the configuration
2132files are edited. However, if an optional configuration file is deleted, it is
9b371988
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2133necessary to touch the associated non-optional file (that is,
2134&_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
168e428f
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2135
2136
f89d2485 2137.section "OS-specific header files" "SECID30"
9b371988
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2138.cindex "&_os.h_&"
2139.cindex "building Exim" "OS-specific C header files"
2140The &_OS_& directory contains a number of files with names of the form
2141&_os.h-<ostype>_&. These are system-specific C header files that should not
168e428f 2142normally need to be changed. There is a list of macro settings that are
9b371988 2143recognized in the file &_OS/os.configuring_&, which should be consulted if you
168e428f
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2144are porting Exim to a new operating system.
2145
2146
2147
f89d2485
PH
2148.section "Overriding build-time options for the monitor" "SECID31"
2149.cindex "building Eximon"
168e428f
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2150A similar process is used for overriding things when building the Exim monitor,
2151where the files that are involved are
9b371988
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2152.display
2153&_OS/eximon.conf-Default_&
2154&_OS/eximon.conf-_&<&'ostype'&>
2155&_Local/eximon.conf_&
2156&_Local/eximon.conf-_&<&'ostype'&>
2157&_Local/eximon.conf-_&<&'archtype'&>
2158&_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2159.endd
2160.cindex "&_Local/eximon.conf_&"
168e428f 2161As with Exim itself, the final three files need not exist, and in this case the
9b371988
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2162&_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2163&_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
168e428f
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2164variables of the same name, preceded by EXIMON_. For example, setting
2165EXIMON_LOG_DEPTH in the environment overrides the value of
2166LOG_DEPTH at run time.
4f578862 2167.ecindex IIDbuex
168e428f
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2168
2169
f89d2485 2170.section "Installing Exim binaries and scripts" "SECID32"
9b371988
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2171.cindex "installing Exim"
2172.cindex "BIN_DIRECTORY"
2173The command &`make install`& runs the &(exim_install)& script with no
2174arguments. The script copies binaries and utility scripts into the directory
2175whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2176.cindex "setuid" "installing Exim with"
068aaea8
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2177The install script copies files only if they are newer than the files they are
2178going to replace. The Exim binary is required to be owned by root and have the
9b371988
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2179&'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2180install`& as root so that it can set up the Exim binary in this way. However, in
068aaea8
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2181some special situations (for example, if a host is doing no local deliveries)
2182it may be possible to run Exim without making the binary setuid root (see
9b371988 2183chapter &<<CHAPsecurity>>& for details).
168e428f 2184
9b371988 2185.cindex "CONFIGURE_FILE"
168e428f 2186Exim's run time configuration file is named by the CONFIGURE_FILE setting
9b371988
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2187in &_Local/Makefile_&. If this names a single file, and the file does not
2188exist, the default configuration file &_src/configure.default_& is copied there
168e428f
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2189by the installation script. If a run time configuration file already exists, it
2190is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2191alternative files, no default is installed.
2192
9b371988
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2193.cindex "system aliases file"
2194.cindex "&_/etc/aliases_&"
168e428f
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2195One change is made to the default configuration file when it is installed: the
2196default configuration contains a router that references a system aliases file.
2197The path to this file is set to the value specified by
9b371988 2198SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
168e428f
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2199If the system aliases file does not exist, the installation script creates it,
2200and outputs a comment to the user.
2201
2202The created file contains no aliases, but it does contain comments about the
2203aliases a site should normally have. Mail aliases have traditionally been
9b371988
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2204kept in &_/etc/aliases_&. However, some operating systems are now using
2205&_/etc/mail/aliases_&. You should check if yours is one of these, and change
168e428f
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2206Exim's configuration if necessary.
2207
2208The default configuration uses the local host's name as the only local domain,
9b371988
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2209and is set up to do local deliveries into the shared directory &_/var/mail_&,
2210running as the local user. System aliases and &_.forward_& files in users' home
168e428f
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2211directories are supported, but no NIS or NIS+ support is configured. Domains
2212other than the name of the local host are routed using the DNS, with delivery
2213over SMTP.
2214
168e428f
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2215It is possible to install Exim for special purposes (such as building a binary
2216distribution) in a private part of the file system. You can do this by a
2217command such as
9b371988
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2218.code
2219make DESTDIR=/some/directory/ install
2220.endd
168e428f
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2221This has the effect of pre-pending the specified directory to all the file
2222paths, except the name of the system aliases file that appears in the default
9b371988 2223configuration. (If a default alias file is created, its name &'is'& modified.)
168e428f
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2224For backwards compatibility, ROOT is used if DESTDIR is not set,
2225but this usage is deprecated.
2226
9b371988
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2227.cindex "installing Exim" "what is not installed"
2228Running &'make install'& does not copy the Exim 4 conversion script
2229&'convert4r4'&, or the &'pcretest'& test program. You will probably run the
168e428f 2230first of these only once (if you are upgrading from Exim 3), and the second
9b371988 2231isn't really part of Exim. None of the documentation files in the &_doc_&
168e428f 2232directory are copied, except for the info files when you have set
9b371988 2233INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
168e428f 2234
9b371988 2235For the utility programs, old versions are renamed by adding the suffix &_.O_&
168e428f
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2236to their names. The Exim binary itself, however, is handled differently. It is
2237installed under a name that includes the version number and the compile number,
9b371988
PH
2238for example &_exim-&version;-1_&. The script then arranges for a symbolic link
2239called &_exim_& to point to the binary. If you are updating a previous version
2240of Exim, the script takes care to ensure that the name &_exim_& is never absent
168e428f
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2241from the directory (as seen by other processes).
2242
9b371988
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2243.cindex "installing Exim" "testing the script"
2244If you want to see what the &'make install'& will do before running it for
2245real, you can pass the &%-n%& option to the installation script by this
2246command:
2247.code
2248make INSTALL_ARG=-n install
2249.endd
168e428f
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2250The contents of the variable INSTALL_ARG are passed to the installation
2251script. You do not need to be root to run this test. Alternatively, you can run
2252the installation script directly, but this must be from within the build
2253directory. For example, from the top-level Exim directory you could use this
2254command:
9b371988
PH
2255.code
2256(cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2257.endd
2258.cindex "installing Exim" "install script options"
168e428f
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2259There are two other options that can be supplied to the installation script.
2260
9b371988
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2261.ilist
2262&%-no_chown%& bypasses the call to change the owner of the installed binary
168e428f 2263to root, and the call to make it a setuid binary.
9b371988
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2264.next
2265&%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
168e428f 2266installed binary.
9b371988 2267.endlist
168e428f
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2268
2269INSTALL_ARG can be used to pass these options to the script. For example:
9b371988
PH
2270.code
2271make INSTALL_ARG=-no_symlink install
2272.endd
168e428f
PH
2273The installation script can also be given arguments specifying which files are
2274to be copied. For example, to install just the Exim binary, and nothing else,
2275without creating the symbolic link, you could use:
9b371988
PH
2276.code
2277make INSTALL_ARG='-no_symlink exim' install
2278.endd
168e428f
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2279
2280
2281
9b371988
PH
2282.section "Installing info documentation" "SECTinsinfdoc"
2283.cindex "installing Exim" "&'info'& documentation"
2284Not all systems use the GNU &'info'& system for documentation, and for this
168e428f
PH
2285reason, the Texinfo source of Exim's documentation is not included in the main
2286distribution. Instead it is available separately from the ftp site (see section
9b371988 2287&<<SECTavail>>&).
168e428f 2288
9b371988
PH
2289If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2290source of the documentation is found in the source tree, running &`make
2291install`& automatically builds the info files and installs them.
168e428f
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2292
2293
2294
f89d2485 2295.section "Setting up the spool directory" "SECID33"
9b371988 2296.cindex "spool directory" "creating"
168e428f
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2297When it starts up, Exim tries to create its spool directory if it does not
2298exist. The Exim uid and gid are used for the owner and group of the spool
2299directory. Sub-directories are automatically created in the spool directory as
2300necessary.
2301
2302
2303
2304
f89d2485 2305.section "Testing" "SECID34"
9b371988 2306.cindex "testing" "installation"
168e428f
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2307Having installed Exim, you can check that the run time configuration file is
2308syntactically valid by running the following command, which assumes that the
2309Exim binary directory is within your PATH environment variable:
9b371988
PH
2310.code
2311exim -bV
2312.endd
168e428f
PH
2313If there are any errors in the configuration file, Exim outputs error messages.
2314Otherwise it outputs the version number and build date,
2315the DBM library that is being used, and information about which drivers and
2316other optional code modules are included in the binary.
2317Some simple routing tests can be done by using the address testing option. For
2318example,
9b371988
PH
2319.display
2320&`exim -bt`& <&'local username'&>
2321.endd
168e428f 2322should verify that it recognizes a local mailbox, and
9b371988
PH
2323.display
2324&`exim -bt`& <&'remote address'&>
2325.endd
168e428f
PH
2326a remote one. Then try getting it to deliver mail, both locally and remotely.
2327This can be done by passing messages directly to Exim, without going through a
2328user agent. For example:
9b371988 2329.code
068aaea8
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2330exim -v postmaster@your.domain.example
2331From: user@your.domain.example
2332To: postmaster@your.domain.example
2333Subject: Testing Exim
168e428f 2334
068aaea8
PH
2335This is a test message.
2336^D
9b371988
PH
2337.endd
2338The &%-v%& option causes Exim to output some verification of what it is doing.
168e428f 2339In this case you should see copies of three log lines, one for the message's
9b371988 2340arrival, one for its delivery, and one containing &"Completed"&.
168e428f 2341
9b371988
PH
2342.cindex "delivery" "problems with"
2343If you encounter problems, look at Exim's log files (&'mainlog'& and
2344&'paniclog'&) to see if there is any relevant information there. Another source
168e428f 2345of information is running Exim with debugging turned on, by specifying the
9b371988 2346&%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
168e428f 2347with debugging turned on by a command of the form
9b371988
PH
2348.display
2349&`exim -d -M`& <&'exim-message-id'&>
2350.endd
2351You must be root or an &"admin user"& in order to do this. The &%-d%& option
168e428f 2352produces rather a lot of output, but you can cut this down to specific areas.
9b371988
PH
2353For example, if you use &%-d-all+route%& only the debugging information
2354relevant to routing is included. (See the &%-d%& option in chapter
2355&<<CHAPcommandline>>& for more details.)
168e428f 2356
9b371988
PH
2357.cindex '&"sticky"& bit'
2358.cindex "lock files"
168e428f
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2359One specific problem that has shown up on some sites is the inability to do
2360local deliveries into a shared mailbox directory, because it does not have the
9b371988 2361&"sticky bit"& set on it. By default, Exim tries to create a lock file before
168e428f 2362writing to a mailbox file, and if it cannot create the lock file, the delivery
9b371988 2363is deferred. You can get round this either by setting the &"sticky bit"& on the
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2364directory, or by setting a specific group for local deliveries and allowing
2365that group to create files in the directory (see the comments above the
9b371988 2366&(local_delivery)& transport in the default configuration file). Another
168e428f 2367approach is to configure Exim not to use lock files, but just to rely on
9b371988
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2368&[fcntl()]& locking instead. However, you should do this only if all user
2369agents also use &[fcntl()]& locking. For further discussion of locking issues,
2370see chapter &<<CHAPappendfile>>&.
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2371
2372One thing that cannot be tested on a system that is already running an MTA is
2373the receipt of incoming SMTP mail on the standard SMTP port. However, the
9b371988
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2374&%-oX%& option can be used to run an Exim daemon that listens on some other
2375port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2376&'exim_checkaccess'& utility can be used to check out policy controls on
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2377incoming SMTP mail.
2378
2379Testing a new version on a system that is already running Exim can most easily
2380be done by building a binary with a different CONFIGURE_FILE setting. From
2381within the run time configuration, all other file and directory names
2382that Exim uses can be altered, in order to keep it entirely clear of the
2383production version.
2384
2385
f89d2485 2386.section "Replacing another MTA with Exim" "SECID35"
9b371988 2387.cindex "replacing another MTA"
168e428f
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2388Building and installing Exim for the first time does not of itself put it in
2389general use. The name by which the system's MTA is called by mail user agents
9b371988
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2390is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2391operating system), and it is necessary to make this name point to the &'exim'&
168e428f 2392binary in order to get the user agents to pass messages to Exim. This is
9b371988
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2393normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2394or &_/usr/lib/sendmail_&
2395.cindex "symbolic link" "to &'exim'& binary"
2396a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
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2397privilege and executable status from the old MTA. It is then necessary to stop
2398and restart the mailer daemon, if one is running.
2399
f89d2485 2400.cindex "FreeBSD, MTA indirection"
9b371988 2401.cindex "&_/etc/mail/mailer.conf_&"
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2402Some operating systems have introduced alternative ways of switching MTAs. For
2403example, if you are running FreeBSD, you need to edit the file
9b371988 2404&_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
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2405described. A typical example of the contents of this file for running Exim is
2406as follows:
9b371988
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2407.code
2408sendmail /usr/exim/bin/exim
2409send-mail /usr/exim/bin/exim
2410mailq /usr/exim/bin/exim -bp
2411newaliases /usr/bin/true
2412.endd
2413Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2414your Exim installation is &"live"&. Check it by sending a message from your
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2415favourite user agent.
2416
2417You should consider what to tell your users about the change of MTA. Exim may
2418have different capabilities to what was previously running, and there are
2419various operational differences such as the text of messages produced by
2420command line options and in bounce messages. If you allow your users to make
2421use of Exim's filtering capabilities, you should make the document entitled
9b371988 2422&'Exim's interface to mail filtering'& available to them.
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2423
2424
2425
f89d2485 2426.section "Upgrading Exim" "SECID36"
9b371988 2427.cindex "upgrading Exim"
168e428f
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2428If you are already running Exim on your host, building and installing a new
2429version automatically makes it available to MUAs, or any other programs that
2430call the MTA directly. However, if you are running an Exim daemon, you do need
9b371988
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2431to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2432new binary. You do not need to stop processing mail in order to install a new
068aaea8
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2433version of Exim. The install script does not modify an existing runtime
2434configuration file.
2435
168e428f
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2436
2437
2438
f89d2485 2439.section "Stopping the Exim daemon on Solaris" "SECID37"
9b371988 2440.cindex "Solaris" "stopping Exim on"
168e428f 2441The standard command for stopping the mailer daemon on Solaris is
9b371988
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2442.code
2443/etc/init.d/sendmail stop
2444.endd
2445If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2446fails to stop Exim because it uses the command &'ps -e'& and greps the output
2447for the text &"sendmail"&; this is not present because the actual program name
2448(that is, &"exim"&) is given by the &'ps'& command with these options. A
2449solution is to replace the line that finds the process id with something like
2450.code
2451pid=`cat /var/spool/exim/exim-daemon.pid`
2452.endd
168e428f
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2453to obtain the daemon's pid directly from the file that Exim saves it in.
2454
9b371988 2455Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
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2456still be received from local processes, and if automatic delivery is configured
2457(the normal case), deliveries will still occur.
2458
2459
2460
2461
9b371988
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2462. ////////////////////////////////////////////////////////////////////////////
2463. ////////////////////////////////////////////////////////////////////////////
168e428f 2464
9b371988 2465.chapter "The Exim command line" "CHAPcommandline"
4f578862
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2466.scindex IIDclo1 "command line" "options"
2467.scindex IIDclo2 "options" "command line"
168e428f
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2468Exim's command line takes the standard Unix form of a sequence of options,
2469each starting with a hyphen character, followed by a number of arguments. The
2470options are compatible with the main options of Sendmail, and there are also
2471some additional options, some of which are compatible with Smail 3. Certain
2472combinations of options do not make sense, and provoke an error if used.
2473The form of the arguments depends on which options are set.
2474
2475
f89d2485 2476.section "Setting options by program name" "SECID38"
9b371988
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2477.cindex "&'mailq'&"
2478If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
168e428f 2479were present before any other options.
9b371988 2480The &%-bp%& option requests a listing of the contents of the mail queue on the
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2481standard output.
2482This feature is for compatibility with some systems that contain a command of
2483that name in one of the standard libraries, symbolically linked to
9b371988
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2484&_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2485
2486.cindex "&'rsmtp'&"
2487If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2488were present before any other options, for compatibility with Smail. The
2489&%-bS%& option is used for reading in a number of messages in batched SMTP
2490format.
2491
2492.cindex "&'rmail'&"
2493If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2494&%-oee%& options were present before any other options, for compatibility with
2495Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2496
2497.cindex "&'runq'&"
2498.cindex "queue runner"
2499If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2500were present before any other options, for compatibility with Smail. The &%-q%&
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2501option causes a single queue runner process to be started.
2502
9b371988
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2503.cindex "&'newaliases'&"
2504.cindex "alias file" "building"
2505.cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2506If Exim is called under the name &'newaliases'& it behaves as if the option
2507&%-bi%& were present before any other options, for compatibility with Sendmail.
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2508This option is used for rebuilding Sendmail's alias file. Exim does not have
2509the concept of a single alias file, but can be configured to run a given
9b371988 2510command if called with the &%-bi%& option.
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2511
2512
9b371988
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2513.section "Trusted and admin users" "SECTtrustedadmin"
2514Some Exim options are available only to &'trusted users'& and others are
2515available only to &'admin users'&. In the description below, the phrases &"Exim
2516user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2517EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2518&%exim_group%& options. These do not necessarily have to use the name &"exim"&.
168e428f 2519
9b371988 2520.ilist
f89d2485 2521.cindex "trusted users" "definition of"
9b371988 2522.cindex "user" "trusted definition of"
168e428f 2523The trusted users are root, the Exim user, any user listed in the
9b371988
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2524&%trusted_users%& configuration option, and any user whose current group or any
2525supplementary group is one of those listed in the &%trusted_groups%&
168e428f 2526configuration option. Note that the Exim group is not automatically trusted.
9b371988
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2527
2528.cindex '&"From"& line'
2529.cindex "envelope sender"
2530Trusted users are always permitted to use the &%-f%& option or a leading
2531&"From&~"& line to specify the envelope sender of a message that is passed to
2532Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2533See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2534users to set envelope senders.
2535
2536.cindex "&'From:'& header line"
2537.cindex "&'Sender:'& header line"
2538For a trusted user, there is never any check on the contents of the &'From:'&
2539header line, and a &'Sender:'& line is never added. Furthermore, any existing
2540&'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2541
168e428f
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2542Trusted users may also specify a host name, host address, interface address,
2543protocol name, ident value, and authentication data when submitting a message
2544locally. Thus, they are able to insert messages into Exim's queue locally that
2545have the characteristics of messages received from a remote host. Untrusted
9b371988 2546users may in some circumstances use &%-f%&, but can never set the other values
168e428f 2547that are available to trusted users.
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2548.next
2549.cindex "user" "admin definition of"
2550.cindex "admin user" "definition of"
168e428f 2551The admin users are root, the Exim user, and any user that is a member of the
9b371988 2552Exim group or of any group listed in the &%admin_groups%& configuration option.
168e428f 2553The current group does not have to be one of these groups.
9b371988 2554
168e428f
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2555Admin users are permitted to list the queue, and to carry out certain
2556operations on messages, for example, to force delivery failures. It is also
2557necessary to be an admin user in order to see the full information provided by
2558the Exim monitor, and full debugging output.
9b371988
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2559
2560By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2561Exim to attempt delivery of messages on its queue is restricted to admin users.
2562However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2563option false (that is, specifying &%no_prod_requires_admin%&).
2564
2565Similarly, the use of the &%-bp%& option to list all the messages in the queue
2566is restricted to admin users unless &%queue_list_requires_admin%& is set
168e428f 2567false.
9b371988 2568.endlist
168e428f
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2569
2570
9b371988 2571&*Warning*&: If you configure your system so that admin users are able to
168e428f
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2572edit Exim's configuration file, you are giving those users an easy way of
2573getting root. There is further discussion of this issue at the start of chapter
9b371988 2574&<<CHAPconf>>&.
168e428f
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2575
2576
2577
2578
f89d2485 2579.section "Command line options" "SECID39"
db9452a9
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2580Exim's command line options are described in alphabetical order below. If none
2581of the options that specifies a specific action (such as starting the daemon or
2582a queue runner, or testing an address, or receiving a message in a specific
2583format, or listing the queue) are present, and there is at least one argument
2584on the command line, &%-bm%& (accept a local message on the standard input,
2585with the arguments specifying the recipients) is assumed. Otherwise, Exim
2586outputs a brief message about itself and exits.
168e428f 2587
9b371988
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2588. ////////////////////////////////////////////////////////////////////////////
2589. Insert a stylized XML comment here, to identify the start of the command line
2590. options. This is for the benefit of the Perl script that automatically
2591. creates a man page for the options.
2592. ////////////////////////////////////////////////////////////////////////////
168e428f 2593
9b371988 2594.literal xml
168e428f 2595<!-- === Start of command line options === -->
9b371988 2596.literal off
168e428f
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2597
2598
9b371988
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2599.vlist
2600.vitem &%--%&
2601.oindex "--"
2602.cindex "options" "command line; terminating"
168e428f
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2603This is a pseudo-option whose only purpose is to terminate the options and
2604therefore to cause subsequent command line items to be treated as arguments
2605rather than options, even if they begin with hyphens.
2606
9b371988
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2607.vitem &%--help%&
2608.oindex "&%--help%&"
168e428f
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2609This option causes Exim to output a few sentences stating what it is.
2610The same output is generated if the Exim binary is called with no options and
2611no arguments.
2612
9b371988
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2613.vitem &%-B%&<&'type'&>
2614.oindex "&%-B%&"
2615.cindex "8-bit characters"
2616.cindex "Sendmail compatibility" "8-bit characters"
168e428f
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2617This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2618clean; it ignores this option.
2619
9b371988
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2620.vitem &%-bd%&
2621.oindex "&%-bd%&"
2622.cindex "daemon"
f89d2485 2623.cindex "SMTP" "listener"
9b371988 2624.cindex "queue runner"
168e428f 2625This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
9b371988
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2626the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2627that the daemon should also initiate periodic queue runs.
2628
2629The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2630(debugging) or &%-v%& (verifying) options are set, the daemon does not
168e428f
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2631disconnect from the controlling terminal. When running this way, it can be
2632stopped by pressing ctrl-C.
9b371988 2633
168e428f
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2634By default, Exim listens for incoming connections to the standard SMTP port on
2635all the host's running interfaces. However, it is possible to listen on other
2636ports, on multiple ports, and only on specific interfaces. Chapter
9b371988
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2637&<<CHAPinterfaces>>& contains a description of the options that control this.
2638
168e428f 2639When a listening daemon
9b371988
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2640.cindex "daemon" "process id (pid)"
2641.cindex "pid (process id)" "of daemon"
2642is started without the use of &%-oX%& (that is, without overriding the normal
2643configuration), it writes its process id to a file called &_exim-daemon.pid_&
2644in Exim's spool directory. This location can be overridden by setting
2645PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
168e428f 2646running as root.
9b371988
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2647
2648When &%-oX%& is used on the command line to start a listening daemon, the
2649process id is not written to the normal pid file path. However, &%-oP%& can be
168e428f 2650used to specify a path on the command line if a pid file is required.
9b371988 2651
168e428f 2652The SIGHUP signal
9b371988 2653.cindex "SIGHUP"
3cb1b51e
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2654.cindex "daemon" "restarting"
2655can be used to cause the daemon to re-execute itself. This should be done
2656whenever Exim's configuration file, or any file that is incorporated into it by
2657means of the &%.include%& facility, is changed, and also whenever a new version
2658of Exim is installed. It is not necessary to do this when other files that are
9b371988
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2659referenced from the configuration (for example, alias files) are changed,
2660because these are reread each time they are used.
2661
2662.vitem &%-bdf%&
2663.oindex "&%-bdf%&"
2664This option has the same effect as &%-bd%& except that it never disconnects
2665from the controlling terminal, even when no debugging is specified.
2666
2667.vitem &%-be%&
2668.oindex "&%-be%&"
2669.cindex "testing" "string expansion"
2670.cindex "expansion" "testing"
168e428f
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2671Run Exim in expansion testing mode. Exim discards its root privilege, to
2672prevent ordinary users from using this mode to read otherwise inaccessible
2673files. If no arguments are given, Exim runs interactively, prompting for lines
4f578862 2674of data. Otherwise, it processes each argument in turn.
9b371988
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2675
2676If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2677to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2678used without command line arguments. If successful, it uses the &[readline()]&
168e428f
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2679function, which provides extensive line-editing facilities, for reading the
2680test data. A line history is supported.
9b371988 2681
168e428f 2682Long expansion expressions can be split over several lines by using backslash
068aaea8 2683continuations. As in Exim's run time configuration, white space at the start of
168e428f
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2684continuation lines is ignored. Each argument or data line is passed through the
2685string expansion mechanism, and the result is output. Variable values from the
9b371988 2686configuration file (for example, &$qualify_domain$&) are available, but no
3cb1b51e 2687message-specific values (such as &$sender_domain$&) are set, because no message
f89d2485 2688is being processed (but see &%-bem%& and &%-Mset%&).
168e428f 2689
9b371988
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2690&*Note*&: If you use this mechanism to test lookups, and you change the data
2691files or databases you are using, you must exit and restart Exim before trying
2692the same lookup again. Otherwise, because each Exim process caches the results
2693of lookups, you will just get the same result as before.
9b371988 2694
3cb1b51e
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2695.vitem &%-bem%&&~<&'filename'&>
2696.oindex "&%-bem%&"
2697.cindex "testing" "string expansion"
2698.cindex "expansion" "testing"
2699This option operates like &%-be%& except that it must be followed by the name
2700of a file. For example:
2701.code
2702exim -bem /tmp/testmessage
2703.endd
2704The file is read as a message (as if receiving a locally-submitted non-SMTP
2705message) before any of the test expansions are done. Thus, message-specific
2706variables such as &$message_size$& and &$header_from:$& are available. However,
2707no &'Received:'& header is added to the message. If the &%-t%& option is set,
2708recipients are read from the headers in the normal way, and are shown in the
2709&$recipients$& variable. Note that recipients cannot be given on the command
2710line, because further arguments are taken as strings to expand (just like
2711&%-be%&).
3cb1b51e 2712
9b371988
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2713.vitem &%-bF%&&~<&'filename'&>
2714.oindex "&%-bF%&"
2715.cindex "system filter" "testing"
2716.cindex "testing" "system filter"
2717This option is the same as &%-bf%& except that it assumes that the filter being
168e428f
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2718tested is a system filter. The additional commands that are available only in
2719system filters are recognized.
2720
9b371988
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2721.vitem &%-bf%&&~<&'filename'&>
2722.oindex "&%-bf%&"
2723.cindex "filter" "testing"
2724.cindex "testing" "filter file"
2725.cindex "forward file" "testing"
2726.cindex "testing" "forward file"
2727.cindex "Sieve filter" "testing"
168e428f
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2728This option runs Exim in user filter testing mode; the file is the filter file
2729to be tested, and a test message must be supplied on the standard input. If
2730there are no message-dependent tests in the filter, an empty file can be
2731supplied.
168e428f 2732
9b371988
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2733If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2734can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2735filter and a user filter in the same run. For example:
2736.code
2737exim -bF /system/filter -bf /user/filter </test/message
2738.endd
168e428f
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2739This is helpful when the system filter adds header lines or sets filter
2740variables that are used by the user filter.
168e428f 2741
9b371988
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2742If the test filter file does not begin with one of the special lines
2743.code
2744# Exim filter
2745# Sieve filter
2746.endd
2747it is taken to be a normal &_.forward_& file, and is tested for validity under
2748that interpretation. See sections &<<SECTitenonfilred>>& to
2749&<<SECTspecitredli>>& for a description of the possible contents of non-filter
2750redirection lists.
2751
2752The result of an Exim command that uses &%-bf%&, provided no errors are
168e428f
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2753detected, is a list of the actions that Exim would try to take if presented
2754with the message for real. More details of filter testing are given in the
9b371988
PH
2755separate document entitled &'Exim's interfaces to mail filtering'&.
2756
168e428f 2757When testing a filter file,
9b371988
PH
2758.cindex "&""From""& line"
2759.cindex "envelope sender"
f89d2485 2760.oindex "&%-f%&" "for filter testing"
9b371988
PH
2761the envelope sender can be set by the &%-f%& option,
2762or by a &"From&~"& line at the start of the test message. Various parameters
2763that would normally be taken from the envelope recipient address of the message
2764can be set by means of additional command line options (see the next four
2765options).
2766
2767.vitem &%-bfd%&&~<&'domain'&>
2768.oindex "&%-bfd%&"
f89d2485 2769.vindex "&$qualify_domain$&"
168e428f 2770This sets the domain of the recipient address when a filter file is being
9b371988
PH
2771tested by means of the &%-bf%& option. The default is the value of
2772&$qualify_domain$&.
168e428f 2773
9b371988
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2774.vitem &%-bfl%&&~<&'local&~part'&>
2775.oindex "&%-bfl%&"
168e428f 2776This sets the local part of the recipient address when a filter file is being
9b371988 2777tested by means of the &%-bf%& option. The default is the username of the
168e428f
PH
2778process that calls Exim. A local part should be specified with any prefix or
2779suffix stripped, because that is how it appears to the filter when a message is
2780actually being delivered.
2781
9b371988
PH
2782.vitem &%-bfp%&&~<&'prefix'&>
2783.oindex "&%-bfp%&"
168e428f 2784This sets the prefix of the local part of the recipient address when a filter
9b371988 2785file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
PH
2786prefix.
2787
9b371988
PH
2788.vitem &%-bfs%&&~<&'suffix'&>
2789.oindex "&%-bfs%&"
168e428f 2790This sets the suffix of the local part of the recipient address when a filter
9b371988 2791file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
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2792suffix.
2793
9b371988
PH
2794.vitem &%-bh%&&~<&'IP&~address'&>
2795.oindex "&%-bh%&"
2796.cindex "testing" "incoming SMTP"
2797.cindex "SMTP" "testing incoming"
2798.cindex "testing" "relay control"
2799.cindex "relaying" "testing configuration"
2800.cindex "policy control" "testing"
2801.cindex "debugging" "&%-bh%& option"
168e428f
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2802This option runs a fake SMTP session as if from the given IP address, using the
2803standard input and output. The IP address may include a port number at the end,
2804after a full stop. For example:
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2805.code
2806exim -bh 10.9.8.7.1234
2807exim -bh fe80::a00:20ff:fe86:a061.5678
2808.endd
168e428f 2809When an IPv6 address is given, it is converted into canonical form. In the case
9b371988
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2810of the second example above, the value of &$sender_host_address$& after
2811conversion to the canonical form is
2812&`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2813
168e428f 2814Comments as to what is going on are written to the standard error file. These
9b371988 2815include lines beginning with &"LOG"& for anything that would have been logged.
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2816This facility is provided for testing configuration options for incoming
2817messages, to make sure they implement the required policy. For example, you can
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2818test your relay controls using &%-bh%&.
2819
2820&*Warning 1*&:
2821.cindex "RFC 1413"
db9452a9
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2822You can test features of the configuration that rely on ident (RFC 1413)
2823information by using the &%-oMt%& option. However, Exim cannot actually perform
2824an ident callout when testing using &%-bh%& because there is no incoming SMTP
2825connection.
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2826
2827&*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2828are also skipped when testing using &%-bh%&. If you want these callouts to
2829occur, use &%-bhc%& instead.
2830
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2831Messages supplied during the testing session are discarded, and nothing is
2832written to any of the real log files. There may be pauses when DNS (and other)
9b371988 2833lookups are taking place, and of course these may time out. The &%-oMi%& option
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2834can be used to specify a specific IP interface and port if this is important,
2835and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2836session were authenticated.
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2837
2838The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
168e428f 2839output just states whether a given recipient address from a given host is
9b371988 2840acceptable or not. See section &<<SECTcheckaccess>>&.
168e428f 2841
3cb1b51e 2842Features such as authentication and encryption, where the client input is not
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2843plain text, cannot easily be tested with &%-bh%&. Instead, you should use a
2844specialized SMTP test program such as
3cb1b51e 2845&url(http://jetmore.org/john/code/#swaks,swaks).
3cb1b51e 2846
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2847.vitem &%-bhc%&&~<&'IP&~address'&>
2848.oindex "&%-bhc%&"
2849This option operates in the same way as &%-bh%&, except that address
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2850verification callouts are performed if required. This includes consulting and
2851updating the callout cache database.
2852
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2853.vitem &%-bi%&
2854.oindex "&%-bi%&"
2855.cindex "alias file" "building"
2856.cindex "building alias file"
2857.cindex "Sendmail compatibility" "&%-bi%& option"
2858Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
168e428f 2859Exim does not have the concept of a single alias file, and so it cannot mimic
9b371988 2860this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
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2861tend to appear in various scripts such as NIS make files, so the option must be
2862recognized.
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2863
2864If &%-bi%& is encountered, the command specified by the &%bi_command%&
168e428f 2865configuration option is run, under the uid and gid of the caller of Exim. If
9b371988
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2866the &%-oA%& option is used, its value is passed to the command as an argument.
2867The command set by &%bi_command%& may not contain arguments. The command can
2868use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2869if this is required. If the &%bi_command%& option is not set, calling Exim with
2870&%-bi%& is a no-op.
2871
2872.vitem &%-bm%&
2873.oindex "&%-bm%&"
2874.cindex "local message reception"
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2875This option runs an Exim receiving process that accepts an incoming,
2876locally-generated message on the current input. The recipients are given as the
9b371988 2877command arguments (except when &%-t%& is also present &-- see below). Each
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2878argument can be a comma-separated list of RFC 2822 addresses. This is the
2879default option for selecting the overall action of an Exim call; it is assumed
2880if no other conflicting option is present.
9b371988 2881
168e428f 2882If any addresses in the message are unqualified (have no domain), they are
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2883qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
2884options, as appropriate. The &%-bnq%& option (see below) provides a way of
168e428f 2885suppressing this for special cases.
9b371988 2886
168e428f 2887Policy checks on the contents of local messages can be enforced by means of
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2888the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
2889
2890.cindex "return code" "for &%-bm%&"
2891The return code is zero if the message is successfully accepted. Otherwise, the
2892action is controlled by the &%-oe%&&'x'& option setting &-- see below.
2893
168e428f 2894The format
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2895.cindex "message" "format"
2896.cindex "format" "message"
2897.cindex "&""From""& line"
2898.cindex "UUCP" "&""From""& line"
2899.cindex "Sendmail compatibility" "&""From""& line"
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2900of the message must be as defined in RFC 2822, except that, for
2901compatibility with Sendmail and Smail, a line in one of the forms
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2902.code
2903From sender Fri Jan 5 12:55 GMT 1997
2904From sender Fri, 5 Jan 97 12:55:01
2905.endd
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2906(with the weekday optional, and possibly with additional text after the date)
2907is permitted to appear at the start of the message. There appears to be no
2908authoritative specification of the format of this line. Exim recognizes it by
9b371988 2909matching against the regular expression defined by the &%uucp_from_pattern%&
168e428f 2910option, which can be changed if necessary.
9b371988 2911
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2912.oindex "&%-f%&" "overriding &""From""& line"
2913The specified sender is treated as if it were given as the argument to the
9b371988 2914&%-f%& option, but if a &%-f%& option is also present, its argument is used in
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2915preference to the address taken from the message. The caller of Exim must be a
2916trusted user for the sender of a message to be set in this way.
2917
9b371988
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2918.vitem &%-bnq%&
2919.oindex "&%-bnq%&"
f89d2485 2920.cindex "address qualification, suppressing"
168e428f
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2921By default, Exim automatically qualifies unqualified addresses (those
2922without domains) that appear in messages that are submitted locally (that
2923is, not over TCP/IP). This qualification applies both to addresses in
2924envelopes, and addresses in header lines. Sender addresses are qualified using
9b371988
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2925&%qualify_domain%&, and recipient addresses using &%qualify_recipient%& (which
2926defaults to the value of &%qualify_domain%&).
2927
2928Sometimes, qualification is not wanted. For example, if &%-bS%& (batch SMTP) is
168e428f
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2929being used to re-submit messages that originally came from remote hosts after
2930content scanning, you probably do not want to qualify unqualified addresses in
2931header lines. (Such lines will be present only if you have not enabled a header
2932syntax check in the appropriate ACL.)
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2933
2934The &%-bnq%& option suppresses all qualification of unqualified addresses in
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2935messages that originate on the local host. When this is used, unqualified
2936addresses in the envelope provoke errors (causing message rejection) and
2937unqualified addresses in header lines are left alone.
2938
2939
9b371988
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2940.vitem &%-bP%&
2941.oindex "&%-bP%&"
595028e4 2942.cindex "configuration options" "extracting"
9b371988 2943.cindex "options" "configuration &-- extracting"
168e428f
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2944If this option is given with no arguments, it causes the values of all Exim's
2945main configuration options to be written to the standard output. The values
2946of one or more specific options can be requested by giving their names as
2947arguments, for example:
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2948.code
2949exim -bP qualify_domain hold_domains
2950.endd
595028e4
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2951.cindex "hiding configuration option values"
2952.cindex "configuration options" "hiding value of"
2953.cindex "options" "hiding value of"
9b371988 2954However, any option setting that is preceded by the word &"hide"& in the
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2955configuration file is not shown in full, except to an admin user. For other
2956users, the output is as in this example:
9b371988
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2957.code
2958mysql_servers = <value not displayable>
2959.endd
2960If &%configure_file%& is given as an argument, the name of the run time
168e428f
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2961configuration file is output.
2962If a list of configuration files was supplied, the value that is output here
2963is the name of the file that was actually used.
168e428f 2964
9b371988
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2965.cindex "daemon" "process id (pid)"
2966.cindex "pid (process id)" "of daemon"
2967If &%log_file_path%& or &%pid_file_path%& are given, the names of the
2968directories where log files and daemon pid files are written are output,
2969respectively. If these values are unset, log files are written in a
2970sub-directory of the spool directory called &%log%&, and the pid file is
2971written directly into the spool directory.
2972
2973If &%-bP%& is followed by a name preceded by &`+`&, for example,
2974.code
2975exim -bP +local_domains
2976.endd
168e428f
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2977it searches for a matching named list of any type (domain, host, address, or
2978local part) and outputs what it finds.
9b371988
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2979
2980.cindex "options" "router &-- extracting"
2981.cindex "options" "transport &-- extracting"
2982If one of the words &%router%&, &%transport%&, or &%authenticator%& is given,
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2983followed by the name of an appropriate driver instance, the option settings for
2984that driver are output. For example:
9b371988
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2985.code
2986exim -bP transport local_delivery
2987.endd
168e428f
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2988The generic driver options are output first, followed by the driver's private
2989options. A list of the names of drivers of a particular type can be obtained by
9b371988
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2990using one of the words &%router_list%&, &%transport_list%&, or
2991&%authenticator_list%&, and a complete list of all drivers with their option
2992settings can be obtained by using &%routers%&, &%transports%&, or
2993&%authenticators%&.
168e428f
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2994
2995
9b371988
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2996.vitem &%-bp%&
2997.oindex "&%-bp%&"
2998.cindex "queue" "listing messages on"
2999.cindex "listing" "messages on the queue"
168e428f 3000This option requests a listing of the contents of the mail queue on the
9b371988 3001standard output. If the &%-bp%& option is followed by a list of message ids,
168e428f 3002just those messages are listed. By default, this option can be used only by an
9b371988 3003admin user. However, the &%queue_list_requires_admin%& option can be set false
168e428f 3004to allow any user to see the queue.
168e428f 3005
9b371988
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3006Each message on the queue is displayed as in the following example:
3007.code
300825m 2.9K 0t5C6f-0000c8-00 <alice@wonderland.fict.example>
3009 red.king@looking-glass.fict.example
3010 <other addresses>
3011.endd
3012.cindex "message" "size in queue listing"
3013.cindex "size" "of message"
3014The first line contains the length of time the message has been on the queue
168e428f
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3015(in this case 25 minutes), the size of the message (2.9K), the unique local
3016identifier for the message, and the message sender, as contained in the
3017envelope. For bounce messages, the sender address is empty, and appears as
9b371988 3018&"<>"&. If the message was submitted locally by an untrusted user who overrode
168e428f
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3019the default sender address, the user's login name is shown in parentheses
3020before the sender address.
9b371988
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3021
3022.cindex "frozen messages" "in queue listing"
3023If the message is frozen (attempts to deliver it are suspended) then the text
3024&"*** frozen ***"& is displayed at the end of this line.
3025
168e428f
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3026The recipients of the message (taken from the envelope, not the headers) are
3027displayed on subsequent lines. Those addresses to which the message has already
3028been delivered are marked with the letter D. If an original address gets
3029expanded into several addresses via an alias or forward file, the original is
3030displayed with a D only when deliveries for all of its child addresses are
3031complete.
3032
3033
9b371988
PH
3034.vitem &%-bpa%&
3035.oindex "&%-bpa%&"
3036This option operates like &%-bp%&, but in addition it shows delivered addresses
168e428f 3037that were generated from the original top level address(es) in each message by
9b371988
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3038alias or forwarding operations. These addresses are flagged with &"+D"& instead
3039of just &"D"&.
168e428f
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3040
3041
9b371988
PH
3042.vitem &%-bpc%&
3043.oindex "&%-bpc%&"
3044.cindex "queue" "count of messages on"
168e428f
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3045This option counts the number of messages on the queue, and writes the total
3046to the standard output. It is restricted to admin users, unless
9b371988 3047&%queue_list_requires_admin%& is set false.
168e428f
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3048
3049
9b371988
PH
3050.vitem &%-bpr%&
3051.oindex "&%-bpr%&"
3052This option operates like &%-bp%&, but the output is not sorted into
168e428f
PH
3053chronological order of message arrival. This can speed it up when there are
3054lots of messages on the queue, and is particularly useful if the output is
3055going to be post-processed in a way that doesn't need the sorting.
3056
9b371988
PH
3057.vitem &%-bpra%&
3058.oindex "&%-bpra%&"
3059This option is a combination of &%-bpr%& and &%-bpa%&.
168e428f 3060
9b371988
PH
3061.vitem &%-bpru%&