Added some index entries for the "hide" option (or option prefix). Closes: bug 524.
[exim.git] / doc / doc-docbook / spec.xfpt
CommitLineData
86058a4a 1. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.23 2007/08/25 12:33:01 magnus Exp $
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2.
3. /////////////////////////////////////////////////////////////////////////////
4. This is the primary source of the Exim Manual. It is an xfpt document that is
5. converted into DocBook XML for subsequent conversion into printing and online
6. formats. The markup used herein is "standard" xfpt markup, with some extras.
7. The markup is summarized in a file called Markup.txt.
8. /////////////////////////////////////////////////////////////////////////////
9
10.include stdflags
11.include stdmacs
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12
13. /////////////////////////////////////////////////////////////////////////////
33393583 14. This outputs the standard DocBook boilerplate.
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15. /////////////////////////////////////////////////////////////////////////////
16
33393583 17.docbook
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18
19. /////////////////////////////////////////////////////////////////////////////
20. These lines are processing instructions for the Simple DocBook Processor that
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21. Philip Hazel has developed as a less cumbersome way of making PostScript and
22. PDFs than using xmlto and fop. They will be ignored by all other XML
23. processors.
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24. /////////////////////////////////////////////////////////////////////////////
25
26.literal xml
27<?sdop
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28 foot_right_recto="&chaptertitle; (&chapternumber;)"
29 foot_right_verso="&chaptertitle; (&chapternumber;)"
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30 toc_chapter_blanks="yes,yes"
31 table_warn_soft_overflow="no"
32?>
33.literal off
9b371988 34
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35. /////////////////////////////////////////////////////////////////////////////
36. This generate the outermost <book> element that wraps then entire document.
37. /////////////////////////////////////////////////////////////////////////////
38
39.book
40
41. /////////////////////////////////////////////////////////////////////////////
42. These definitions set some parameters and save some typing. Remember that
43. the <bookinfo> element must also be updated for each new edition.
44. /////////////////////////////////////////////////////////////////////////////
45
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46.set previousversion "4.66"
47.set version "4.67"
48
33393583 49.set ACL "access control lists (ACLs)"
f89d2485 50.set I "&nbsp;&nbsp;&nbsp;&nbsp;"
33393583 51
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52
53. /////////////////////////////////////////////////////////////////////////////
54. Additional xfpt markup used by this document, over and above the default
55. provided in the xfpt library.
56. /////////////////////////////////////////////////////////////////////////////
57
58. --- Override the &$ flag to automatically insert a $ with the variable name
59
60.flag &$ $& "<varname>$" "</varname>"
61
62. --- Short flags for daggers in option headings. They will always be inside
63. --- an italic string, but we want the daggers to be roman.
64
65.flag &!! "</emphasis>&dagger;<emphasis>"
66.flag &!? "</emphasis>&Dagger;<emphasis>"
67
68. --- A macro for an Exim option definition heading, generating a one-line
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69. --- table with four columns. For cases when the option name is given with
70. --- a space, so that it can be split, a fifth argument is used for the
71. --- index entry.
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72
73.macro option
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74.arg 5
75.oindex "&%$5%&"
76.endarg
77.arg -5
3cb1b51e 78.oindex "&%$1%&"
0a4e3112 79.endarg
f89d2485 80.itable all 0 0 4 8* left 6* center 6* center 6* right
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81.row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&"
82.endtable
83.endmacro
84
85. --- A macro for the common 2-column tables. The width of the first column
86. --- is suitable for the many tables at the start of the main options chapter;
87. --- the small number of other 2-column tables override it.
88
db9452a9 89.macro table2 196pt 254pt
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90.itable none 0 0 2 $1 left $2 left
91.endmacro
92
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93. --- A macro that generates .row, but puts &I; at the start of the first
94. --- argument, thus indenting it. Assume a minimum of two arguments, and
95. --- allow up to four arguments, which is as many as we'll ever need.
96
97.macro irow
98.arg 4
99.row "&I;$1" "$2" "$3" "$4"
100.endarg
101.arg -4
102.arg 3
103.row "&I;$1" "$2" "$3"
104.endarg
105.arg -3
106.row "&I;$1" "$2"
107.endarg
108.endarg
109.endmacro
110
111. --- Macros for option, variable, and concept index entries. For a "range"
112. --- style of entry, use .scindex for the start and .ecindex for the end. The
113. --- first argument of .scindex and the only argument of .ecindex must be the
114. --- ID that ties them together.
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115
116.macro cindex
117&<indexterm role="concept">&
118&<primary>&$1&</primary>&
119.arg 2
120&<secondary>&$2&</secondary>&
121.endarg
122&</indexterm>&
123.endmacro
124
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125.macro scindex
126&<indexterm role="concept" id="$1" class="startofrange">&
127&<primary>&$2&</primary>&
128.arg 3
129&<secondary>&$3&</secondary>&
130.endarg
131&</indexterm>&
132.endmacro
133
134.macro ecindex
135&<indexterm role="concept" startref="$1" class="endofrange"/>&
136.endmacro
137
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138.macro oindex
139&<indexterm role="option">&
140&<primary>&$1&</primary>&
141.arg 2
142&<secondary>&$2&</secondary>&
143.endarg
144&</indexterm>&
145.endmacro
146
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147.macro vindex
148&<indexterm role="variable">&
149&<primary>&$1&</primary>&
150.arg 2
151&<secondary>&$2&</secondary>&
152.endarg
153&</indexterm>&
154.endmacro
155
9b371988 156.macro index
f89d2485 157.echo "** Don't use .index; use .cindex or .oindex or .vindex"
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158.endmacro
159. ////////////////////////////////////////////////////////////////////////////
160
161
162. ////////////////////////////////////////////////////////////////////////////
163. The <bookinfo> element is removed from the XML before processing for Ascii
164. output formats.
165. ////////////////////////////////////////////////////////////////////////////
166
167.literal xml
168<bookinfo>
169<title>Specification of the Exim Mail Transfer Agent</title>
170<titleabbrev>The Exim MTA</titleabbrev>
f89d2485 171<date>10 April 2007</date>
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172<author><firstname>Philip</firstname><surname>Hazel</surname></author>
173<authorinitials>PH</authorinitials>
174<affiliation><orgname>University of Cambridge Computing Service</orgname></affiliation>
175<address>New Museums Site, Pembroke Street, Cambridge CB2 3QH, England</address>
176<revhistory><revision>
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177 <revnumber>4.67</revnumber>
178 <date>10 April 2007</date>
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179 <authorinitials>PH</authorinitials>
180</revision></revhistory>
ad268134 181<copyright><year>2007</year><holder>University of Cambridge</holder></copyright>
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182</bookinfo>
183.literal off
184
185
186. /////////////////////////////////////////////////////////////////////////////
187. This chunk of literal XML implements index entries of the form "x, see y" and
188. "x, see also y". However, the DocBook DTD doesn't allow <indexterm> entries
189. at the top level, so we have to put the .chapter directive first.
190. /////////////////////////////////////////////////////////////////////////////
191
f89d2485 192.chapter "Introduction" "CHID1"
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193.literal xml
194
f89d2485 195<indexterm role="variable">
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196 <primary>$1, $2, etc.</primary>
197 <see><emphasis>numerical variables</emphasis></see>
198</indexterm>
199<indexterm role="concept">
200 <primary>address</primary>
201 <secondary>rewriting</secondary>
202 <see><emphasis>rewriting</emphasis></see>
203</indexterm>
204<indexterm role="concept">
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205 <primary>Bounce Address Tag Validation</primary>
206 <see><emphasis>BATV</emphasis></see>
207</indexterm>
208<indexterm role="concept">
209 <primary>Client SMTP Authorization</primary>
210 <see><emphasis>CSA</emphasis></see>
211</indexterm>
212<indexterm role="concept">
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213 <primary>CR character</primary>
214 <see><emphasis>carriage return</emphasis></see>
215</indexterm>
216<indexterm role="concept">
217 <primary>CRL</primary>
218 <see><emphasis>certificate revocation list</emphasis></see>
219</indexterm>
220<indexterm role="concept">
221 <primary>delivery</primary>
222 <secondary>failure report</secondary>
223 <see><emphasis>bounce message</emphasis></see>
224</indexterm>
225<indexterm role="concept">
226 <primary>dialup</primary>
227 <see><emphasis>intermittently connected hosts</emphasis></see>
228</indexterm>
229<indexterm role="concept">
230 <primary>exiscan</primary>
231 <see><emphasis>content scanning</emphasis></see>
232</indexterm>
233<indexterm role="concept">
234 <primary>failover</primary>
235 <see><emphasis>fallback</emphasis></see>
236</indexterm>
237<indexterm role="concept">
238 <primary>fallover</primary>
239 <see><emphasis>fallback</emphasis></see>
240</indexterm>
241<indexterm role="concept">
242 <primary>filter</primary>
243 <secondary>Sieve</secondary>
244 <see><emphasis>Sieve filter</emphasis></see>
245</indexterm>
246<indexterm role="concept">
247 <primary>ident</primary>
248 <see><emphasis>RFC 1413</emphasis></see>
249</indexterm>
250<indexterm role="concept">
251 <primary>LF character</primary>
252 <see><emphasis>linefeed</emphasis></see>
253</indexterm>
254<indexterm role="concept">
255 <primary>maximum</primary>
256 <see><emphasis>limit</emphasis></see>
257</indexterm>
258<indexterm role="concept">
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259 <primary>monitor</primary>
260 <see><emphasis>Exim monitor</emphasis></see>
261</indexterm>
262<indexterm role="concept">
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263 <primary>no_<emphasis>xxx</emphasis></primary>
264 <see>entry for xxx</see>
265</indexterm>
266<indexterm role="concept">
267 <primary>NUL</primary>
268 <see><emphasis>binary zero</emphasis></see>
269</indexterm>
270<indexterm role="concept">
271 <primary>passwd file</primary>
272 <see><emphasis>/etc/passwd</emphasis></see>
273</indexterm>
274<indexterm role="concept">
275 <primary>process id</primary>
276 <see><emphasis>pid</emphasis></see>
277</indexterm>
278<indexterm role="concept">
279 <primary>RBL</primary>
280 <see><emphasis>DNS list</emphasis></see>
281</indexterm>
282<indexterm role="concept">
283 <primary>redirection</primary>
284 <see><emphasis>address redirection</emphasis></see>
285</indexterm>
286<indexterm role="concept">
287 <primary>return path</primary>
288 <seealso><emphasis>envelope sender</emphasis></seealso>
289</indexterm>
290<indexterm role="concept">
291 <primary>scanning</primary>
292 <see><emphasis>content scanning</emphasis></see>
293</indexterm>
294<indexterm role="concept">
295 <primary>SSL</primary>
296 <see><emphasis>TLS</emphasis></see>
297</indexterm>
298<indexterm role="concept">
299 <primary>string</primary>
300 <secondary>expansion</secondary>
301 <see><emphasis>expansion</emphasis></see>
302</indexterm>
303<indexterm role="concept">
304 <primary>top bit</primary>
305 <see><emphasis>8-bit characters</emphasis></see>
306</indexterm>
307<indexterm role="concept">
308 <primary>variables</primary>
309 <see><emphasis>expansion, variables</emphasis></see>
310</indexterm>
311<indexterm role="concept">
312 <primary>zero, binary</primary>
313 <see><emphasis>binary zero</emphasis></see>
314</indexterm>
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315
316.literal off
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317
318
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319. /////////////////////////////////////////////////////////////////////////////
320. This is the real start of the first chapter. See the comment above as to why
321. we can't have the .chapter line here.
322. chapter "Introduction"
323. /////////////////////////////////////////////////////////////////////////////
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324
325Exim is a mail transfer agent (MTA) for hosts that are running Unix or
326Unix-like operating systems. It was designed on the assumption that it would be
327run on hosts that are permanently connected to the Internet. However, it can be
328used on intermittently connected hosts with suitable configuration adjustments.
329
330Configuration files currently exist for the following operating systems: AIX,
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331BSD/OS (aka BSDI), Darwin (Mac OS X), DGUX, Dragonfly, FreeBSD, GNU/Hurd,
332GNU/Linux, HI-OSF (Hitachi), HI-UX, HP-UX, IRIX, MIPS RISCOS, NetBSD, OpenBSD,
333OpenUNIX, QNX, SCO, SCO SVR4.2 (aka UNIX-SV), Solaris (aka SunOS5), SunOS4,
334Tru64-Unix (formerly Digital UNIX, formerly DEC-OSF1), Ultrix, and Unixware.
335Some of these operating systems are no longer current and cannot easily be
336tested, so the configuration files may no longer work in practice.
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337
338There are also configuration files for compiling Exim in the Cygwin environment
339that can be installed on systems running Windows. However, this document does
340not contain any information about running Exim in the Cygwin environment.
341
342The terms and conditions for the use and distribution of Exim are contained in
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343the file &_NOTICE_&. Exim is distributed under the terms of the GNU General
344Public Licence, a copy of which may be found in the file &_LICENCE_&.
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345
346The use, supply or promotion of Exim for the purpose of sending bulk,
347unsolicited electronic mail is incompatible with the basic aims of the program,
348which revolve around the free provision of a service that enhances the quality
349of personal communications. The author of Exim regards indiscriminate
350mass-mailing as an antisocial, irresponsible abuse of the Internet.
351
352Exim owes a great deal to Smail 3 and its author, Ron Karr. Without the
353experience of running and working on the Smail 3 code, I could never have
354contemplated starting to write a new MTA. Many of the ideas and user interfaces
355were originally taken from Smail 3, though the actual code of Exim is entirely
356new, and has developed far beyond the initial concept.
357
358Many people, both in Cambridge and around the world, have contributed to the
359development and the testing of Exim, and to porting it to various operating
360systems. I am grateful to them all. The distribution now contains a file called
9b371988 361&_ACKNOWLEDGMENTS_&, in which I have started recording the names of
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362contributors.
363
364
f89d2485 365.section "Exim documentation" "SECID1"
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366.new
367.cindex "documentation"
368This edition of the Exim specification applies to version &version; of Exim.
369Substantive changes from the &previousversion; edition are marked in some
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370renditions of the document; this paragraph is so marked if the rendition is
371capable of showing a change indicator.
9b371988 372.wen
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373
374This document is very much a reference manual; it is not a tutorial. The reader
375is expected to have some familiarity with the SMTP mail transfer protocol and
376with general Unix system administration. Although there are some discussions
377and examples in places, the information is mostly organized in a way that makes
378it easy to look up, rather than in a natural order for sequential reading.
379Furthermore, the manual aims to cover every aspect of Exim in detail, including
380a number of rarely-used, special-purpose features that are unlikely to be of
381very wide interest.
382
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383.cindex "books about Exim"
384An &"easier"& discussion of Exim which provides more in-depth explanatory,
385introductory, and tutorial material can be found in a book entitled &'The Exim
386SMTP Mail Server'&, published by UIT Cambridge
387(&url(http://www.uit.co.uk/exim-book/)).
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388
389This book also contains a chapter that gives a general introduction to SMTP and
390Internet mail. Inevitably, however, the book is unlikely to be fully up-to-date
391with the latest release of Exim. (Note that the earlier book about Exim,
392published by O'Reilly, covers Exim 3, and many things have changed in Exim 4.)
393
9b371988 394.cindex "Debian" "information sources"
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395If you are using a Debian distribution of Exim, you will find information about
396Debian-specific features in the file
f89d2485 397&_/usr/share/doc/exim4-base/README.Debian_&.
9b371988 398The command &(man update-exim.conf)& is another source of Debian-specific
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399information.
400
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401.cindex "&_doc/NewStuff_&"
402.cindex "&_doc/ChangeLog_&"
403.cindex "change log"
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404As the program develops, there may be features in newer versions that have not
405yet made it into this document, which is updated only when the most significant
406digit of the fractional part of the version number changes. Specifications of
407new features that are not yet in this manual are placed in the file
9b371988 408&_doc/NewStuff_& in the Exim distribution.
168e428f 409
9b371988 410Some features may be classified as &"experimental"&. These may change
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411incompatibly while they are developing, or even be withdrawn. For this reason,
412they are not documented in this manual. Information about experimental features
9b371988 413can be found in the file &_doc/experimental.txt_&.
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414
415All changes to the program (whether new features, bug fixes, or other kinds of
9b371988 416change) are noted briefly in the file called &_doc/ChangeLog_&.
168e428f 417
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418.cindex "&_doc/spec.txt_&"
419This specification itself is available as an ASCII file in &_doc/spec.txt_& so
420that it can easily be searched with a text editor. Other files in the &_doc_&
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421directory are:
422
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423.table2 100pt
424.row &_OptionLists.txt_& "list of all options in alphabetical order"
425.row &_dbm.discuss.txt_& "discussion about DBM libraries"
426.row &_exim.8_& "a man page of Exim's command line options"
427.row &_experimental.txt_& "documentation of experimental features"
428.row &_filter.txt_& "specification of the filter language"
429.row &_pcrepattern.txt_& "specification of PCRE regular expressions"
430.row &_pcretest.txt_& "specification of the PCRE testing program"
431.row &_Exim3.upgrade_& "upgrade notes from release 2 to release 3"
432.row &_Exim4.upgrade_& "upgrade notes from release 3 to release 4"
433.endtable
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434
435The main specification and the specification of the filtering language are also
436available in other formats (HTML, PostScript, PDF, and Texinfo). Section
9b371988 437&<<SECTavail>>& below tells you how to get hold of these.
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438
439
440
f89d2485 441.section "FTP and web sites" "SECID2"
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442.cindex "web site"
443.cindex "FTP site"
068aaea8 444The primary site for Exim source distributions is currently the University of
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445Cambridge's FTP site, whose contents are described in &'Where to find the Exim
446distribution'& below. In addition, there is a web site and an FTP site at
447&%exim.org%&. These are now also hosted at the University of Cambridge. The
448&%exim.org%& site was previously hosted for a number of years by Energis
449Squared, formerly Planet Online Ltd, whose support I gratefully acknowledge.
450
451.cindex "wiki"
452.cindex "FAQ"
f89d2485 453.new
168e428f 454As well as Exim distribution tar files, the Exim web site contains a number of
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455differently formatted versions of the documentation. A recent addition to the
456online information is the Exim wiki (&url(http://www.exim.org/eximwiki/)),
457which contains what used to be a separate FAQ, as well as various other
458examples, tips, and know-how that have been contributed by Exim users.
459
460.cindex Bugzilla
461An Exim Bugzilla exists at &url(http://www.exim.org/bugzilla/). You can use
462this to report bugs, and also to add items to the wish list. Please search
463first to check that you are not duplicating a previous entry.
464.wen
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465
466
467
f89d2485 468.section "Mailing lists" "SECID3"
9b371988 469.cindex "mailing lists" "for Exim users"
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470.new
471The following Exim mailing lists exist:
168e428f 472
9b371988 473.table2 140pt
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474.row &'exim-users@exim.org'& "General discussion list"
475.row &'exim-dev@exim.org'& "Discussion of bugs, enhancements, etc."
476.row &'exim-announce@exim.org'& "Moderated, low volume announcements list"
477.row &'exim-future@exim.org'& "Discussion of long-term development"
9b371988 478.endtable
f89d2485 479.wen
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480
481You can subscribe to these lists, change your existing subscriptions, and view
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482or search the archives via the mailing lists link on the Exim home page.
483.cindex "Debian" "mailing list for"
4f578862 484If you are using a Debian distribution of Exim, you may wish to subscribe to
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485the Debian-specific mailing list &'pkg-exim4-users@lists.alioth.debian.org'&
486via this web page:
487.display
488&url(http://lists.alioth.debian.org/mailman/listinfo/pkg-exim4-users)
489.endd
490Please ask Debian-specific questions on this list and not on the general Exim
491lists.
9b371988 492
f89d2485 493.section "Exim training" "SECID4"
9b371988 494.cindex "training courses"
068aaea8 495From time to time (approximately annually at the time of writing), training
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496courses are run by the author of Exim in Cambridge, UK. Details of any
497forthcoming courses can be found on the web site
498&url(http://www-tus.csx.cam.ac.uk/courses/exim/).
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499
500
f89d2485 501.section "Bug reports" "SECID5"
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502.cindex "bug reports"
503.cindex "reporting bugs"
504Reports of obvious bugs should be emailed to &'bugs@exim.org'&. However, if you
505are unsure whether some behaviour is a bug or not, the best thing to do is to
506post a message to the &'exim-dev'& mailing list and have it discussed.
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507
508
509
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510.section "Where to find the Exim distribution" "SECTavail"
511.cindex "FTP site"
512.cindex "distribution" "ftp site"
168e428f 513The master ftp site for the Exim distribution is
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514.display
515&*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim*&
516.endd
168e428f 517This is mirrored by
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518.display
519&*ftp://ftp.exim.org/pub/exim*&
520.endd
521The file references that follow are relative to the &_exim_& directories at
522these sites. There are now quite a number of independent mirror sites around
523the world. Those that I know about are listed in the file called &_Mirrors_&.
524
525Within the &_exim_& directory there are subdirectories called &_exim3_& (for
526previous Exim 3 distributions), &_exim4_& (for the latest Exim 4
527distributions), and &_Testing_& for testing versions. In the &_exim4_&
168e428f 528subdirectory, the current release can always be found in files called
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529.display
530&_exim-n.nn.tar.gz_&
531&_exim-n.nn.tar.bz2_&
532.endd
533where &'n.nn'& is the highest such version number in the directory. The two
168e428f 534files contain identical data; the only difference is the type of compression.
9b371988 535The &_.bz2_& file is usually a lot smaller than the &_.gz_& file.
168e428f 536
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537.cindex "distribution" "signing details"
538.cindex "distribution" "public key"
539.cindex "public key for signed distribution"
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540The distributions are currently signed with Philip Hazel's GPG key. The
541corresponding public key is available from a number of keyservers, and there is
9b371988 542also a copy in the file &_Public-Key_&. The signatures for the tar bundles are
168e428f 543in:
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544.display
545&_exim-n.nn.tar.gz.sig_&
546&_exim-n.nn.tar.bz2.sig_&
547.endd
168e428f 548For each released version, the log of changes is made separately available in a
9b371988 549separate file in the directory &_ChangeLogs_& so that it is possible to
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550find out what has changed without having to download the entire distribution.
551
9b371988 552.cindex "documentation" "available formats"
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553The main distribution contains ASCII versions of this specification and other
554documentation; other formats of the documents are available in separate files
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555inside the &_exim4_& directory of the FTP site:
556.display
557&_exim-html-n.nn.tar.gz_&
558&_exim-pdf-n.nn.tar.gz_&
559&_exim-postscript-n.nn.tar.gz_&
560&_exim-texinfo-n.nn.tar.gz_&
561.endd
562These tar files contain only the &_doc_& directory, not the complete
563distribution, and are also available in &_.bz2_& as well as &_.gz_& forms.
168e428f 564
168e428f 565
f89d2485 566.section "Limitations" "SECID6"
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567.ilist
568.cindex "limitations of Exim"
569.cindex "bang paths" "not handled by Exim"
570Exim is designed for use as an Internet MTA, and therefore handles addresses in
571RFC 2822 domain format only. It cannot handle UUCP &"bang paths"&, though
572simple two-component bang paths can be converted by a straightforward rewriting
573configuration. This restriction does not prevent Exim from being interfaced to
574UUCP as a transport mechanism, provided that domain addresses are used.
575.next
576.cindex "domainless addresses"
577.cindex "address" "without domain"
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578Exim insists that every address it handles has a domain attached. For incoming
579local messages, domainless addresses are automatically qualified with a
580configured domain value. Configuration options specify from which remote
581systems unqualified addresses are acceptable. These are then qualified on
582arrival.
9b371988
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583.next
584.cindex "transport" "external"
585.cindex "external transports"
586The only external transport mechanisms that are currently implemented are SMTP
587and LMTP over a TCP/IP network (including support for IPv6). However, a pipe
168e428f 588transport is available, and there are facilities for writing messages to files
9b371988
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589and pipes, optionally in &'batched SMTP'& format; these facilities can be used
590to send messages to other transport mechanisms such as UUCP, provided they can
591handle domain-style addresses. Batched SMTP input is also catered for.
592.next
593Exim is not designed for storing mail for dial-in hosts. When the volumes of
594such mail are large, it is better to get the messages &"delivered"& into files
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595(that is, off Exim's queue) and subsequently passed on to the dial-in hosts by
596other means.
9b371988
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597.next
598Although Exim does have basic facilities for scanning incoming messages, these
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599are not comprehensive enough to do full virus or spam scanning. Such operations
600are best carried out using additional specialized software packages. If you
601compile Exim with the content-scanning extension, straightforward interfaces to
602a number of common scanners are provided.
9b371988 603.endlist
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604
605
f89d2485 606.section "Run time configuration" "SECID7"
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607Exim's run time configuration is held in a single text file that is divided
608into a number of sections. The entries in this file consist of keywords and
609values, in the style of Smail 3 configuration files. A default configuration
610file which is suitable for simple online installations is provided in the
9b371988 611distribution, and is described in chapter &<<CHAPdefconfil>>& below.
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612
613
f89d2485 614.section "Calling interface" "SECID8"
9b371988 615.cindex "Sendmail compatibility" "command line interface"
168e428f 616Like many MTAs, Exim has adopted the Sendmail command line interface so that it
9b371988
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617can be a straight replacement for &_/usr/lib/sendmail_& or
618&_/usr/sbin/sendmail_& when sending mail, but you do not need to know anything
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619about Sendmail in order to run Exim. For actions other than sending messages,
620Sendmail-compatible options also exist, but those that produce output (for
9b371988 621example, &%-bp%&, which lists the messages on the queue) do so in Exim's own
168e428f 622format. There are also some additional options that are compatible with Smail
9b371988 6233, and some further options that are new to Exim. Chapter &<<CHAPcommandline>>&
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624documents all Exim's command line options. This information is automatically
625made into the man page that forms part of the Exim distribution.
626
627Control of messages on the queue can be done via certain privileged command
9b371988
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628line options. There is also an optional monitor program called &'eximon'&,
629which displays current information in an X window, and which contains a menu
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630interface to Exim's command line administration options.
631
632
633
f89d2485 634.section "Terminology" "SECID9"
9b371988
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635.cindex "terminology definitions"
636.cindex "body of message" "definition of"
637The &'body'& of a message is the actual data that the sender wants to transmit.
638It is the last part of a message, and is separated from the &'header'& (see
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639below) by a blank line.
640
9b371988 641.cindex "bounce message" "definition of"
168e428f 642When a message cannot be delivered, it is normally returned to the sender in a
9b371988
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643delivery failure message or a &"non-delivery report"& (NDR). The term
644&'bounce'& is commonly used for this action, and the error reports are often
645called &'bounce messages'&. This is a convenient shorthand for &"delivery
646failure error report"&. Such messages have an empty sender address in the
647message's &'envelope'& (see below) to ensure that they cannot themselves give
648rise to further bounce messages.
649
650The term &'default'& appears frequently in this manual. It is used to qualify a
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651value which is used in the absence of any setting in the configuration. It may
652also qualify an action which is taken unless a configuration setting specifies
653otherwise.
654
9b371988 655The term &'defer'& is used when the delivery of a message to a specific
168e428f 656destination cannot immediately take place for some reason (a remote host may be
9b371988 657down, or a user's local mailbox may be full). Such deliveries are &'deferred'&
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658until a later time.
659
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660The word &'domain'& is sometimes used to mean all but the first component of a
661host's name. It is &'not'& used in that sense here, where it normally refers to
662the part of an email address following the @ sign.
168e428f 663
f89d2485 664.cindex "envelope, definition of"
9b371988
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665.cindex "sender" "definition of"
666A message in transit has an associated &'envelope'&, as well as a header and a
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667body. The envelope contains a sender address (to which bounce messages should
668be delivered), and any number of recipient addresses. References to the
669sender or the recipients of a message usually mean the addresses in the
670envelope. An MTA uses these addresses for delivery, and for returning bounce
671messages, not the addresses that appear in the header lines.
672
f89d2485 673.cindex "message" "header, definition of"
9b371988
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674.cindex "header section" "definition of"
675The &'header'& of a message is the first part of a message's text, consisting
676of a number of lines, each of which has a name such as &'From:'&, &'To:'&,
677&'Subject:'&, etc. Long header lines can be split over several text lines by
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678indenting the continuations. The header is separated from the body by a blank
679line.
680
9b371988
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681.cindex "local part" "definition of"
682.cindex "domain" "definition of"
683The term &'local part'&, which is taken from RFC 2822, is used to refer to that
168e428f 684part of an email address that precedes the @ sign. The part that follows the
9b371988 685@ sign is called the &'domain'& or &'mail domain'&.
168e428f 686
9b371988 687.cindex "local delivery" "definition of"
f89d2485 688.cindex "remote delivery, definition of"
9b371988 689The terms &'local delivery'& and &'remote delivery'& are used to distinguish
168e428f 690delivery to a file or a pipe on the local host from delivery by SMTP over
068aaea8 691TCP/IP to another host. As far as Exim is concerned, all hosts other than the
9b371988 692host it is running on are &'remote'&.
168e428f 693
9b371988
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694.cindex "return path" "definition of"
695&'Return path'& is another name that is used for the sender address in a
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696message's envelope.
697
9b371988
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698.cindex "queue" "definition of"
699The term &'queue'& is used to refer to the set of messages awaiting delivery,
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700because this term is in widespread use in the context of MTAs. However, in
701Exim's case the reality is more like a pool than a queue, because there is
702normally no ordering of waiting messages.
703
9b371988
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704.cindex "queue runner" "definition of"
705The term &'queue runner'& is used to describe a process that scans the queue
168e428f 706and attempts to deliver those messages whose retry times have come. This term
9b371988 707is used by other MTAs, and also relates to the command &%runq%&, but in Exim
168e428f
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708the waiting messages are normally processed in an unpredictable order.
709
9b371988
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710.cindex "spool directory" "definition of"
711The term &'spool directory'& is used for a directory in which Exim keeps the
712messages on its queue &-- that is, those that it is in the process of
168e428f 713delivering. This should not be confused with the directory in which local
9b371988
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714mailboxes are stored, which is called a &"spool directory"& by some people. In
715the Exim documentation, &"spool"& is always used in the first sense.
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716
717
718
719
720
721
9b371988
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722. ////////////////////////////////////////////////////////////////////////////
723. ////////////////////////////////////////////////////////////////////////////
168e428f 724
f89d2485 725.chapter "Incorporated code" "CHID2"
9b371988
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726.cindex "incorporated code"
727.cindex "regular expressions" "library"
728.cindex "PCRE"
168e428f
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729A number of pieces of external code are included in the Exim distribution.
730
9b371988
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731.ilist
732Regular expressions are supported in the main Exim program and in the Exim
733monitor using the freely-distributable PCRE library, copyright &copy;
734University of Cambridge. The source is distributed in the directory
735&_src/pcre_&. However, this is a cut-down version of PCRE. If you want to use
736the PCRE library in other programs, you should obtain and install the full
f89d2485
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737version of the library from
738&url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
9b371988 739.next
f89d2485 740.cindex "cdb" "acknowledgment"
168e428f
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741Support for the cdb (Constant DataBase) lookup method is provided by code
742contributed by Nigel Metheringham of (at the time he contributed it) Planet
9b371988
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743Online Ltd. The implementation is completely contained within the code of Exim.
744It does not link against an external cdb library. The code contains the
745following statements:
746
747.blockquote
748Copyright &copy; 1998 Nigel Metheringham, Planet Online Ltd
749
168e428f
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750This program is free software; you can redistribute it and/or modify it under
751the terms of the GNU General Public License as published by the Free Software
752Foundation; either version 2 of the License, or (at your option) any later
753version.
9b371988 754
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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
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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
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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"
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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"
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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,
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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
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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
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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
168e428f
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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
9b371988
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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
068aaea8
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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
9b371988
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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.
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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
168e428f
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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
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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
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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
PH
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
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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
PH
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
PH
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
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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
9b371988
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1658.section "DBM libraries" "SECTdb"
1659.cindex "DBM libraries" "discussion of"
1660.cindex "hints database" "DBM files used for"
168e428f
PH
1661Even if you do not use any DBM files in your configuration, Exim still needs a
1662DBM library in order to operate, because it uses indexed files for its hints
1663databases. Unfortunately, there are a number of DBM libraries in existence, and
1664different operating systems often have different ones installed.
1665
9b371988 1666.cindex "Solaris" "DBM library for"
f89d2485
PH
1667.cindex "IRIX, DBM library for"
1668.cindex "BSD, DBM library for"
1669.cindex "Linux, DBM library for"
168e428f
PH
1670If you are using Solaris, IRIX, one of the modern BSD systems, or a modern
1671Linux distribution, the DBM configuration should happen automatically, and you
1672may be able to ignore this section. Otherwise, you may have to learn more than
1673you would like about DBM libraries from what follows.
1674
9b371988 1675.cindex "&'ndbm'& DBM library"
168e428f 1676Licensed versions of Unix normally contain a library of DBM functions operating
9b371988 1677via the &'ndbm'& interface, and this is what Exim expects by default. Free
168e428f
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1678versions of Unix seem to vary in what they contain as standard. In particular,
1679some early versions of Linux have no default DBM library, and different
1680distributors have chosen to bundle different libraries with their packaged
f89d2485 1681versions. However, the more recent releases seem to have standardized on the
168e428f
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1682Berkeley DB library.
1683
1684Different DBM libraries have different conventions for naming the files they
9b371988 1685use. When a program opens a file called &_dbmfile_&, there are several
168e428f
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1686possibilities:
1687
9b371988
PH
1688.olist
1689A traditional &'ndbm'& implementation, such as that supplied as part of
1690Solaris, operates on two files called &_dbmfile.dir_& and &_dbmfile.pag_&.
1691.next
1692.cindex "&'gdbm'& DBM library"
1693The GNU library, &'gdbm'&, operates on a single file. If used via its &'ndbm'&
168e428f 1694compatibility interface it makes two different hard links to it with names
9b371988 1695&_dbmfile.dir_& and &_dbmfile.pag_&, but if used via its native interface, the
168e428f 1696file name is used unmodified.
9b371988
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1697.next
1698.cindex "Berkeley DB library"
1699The Berkeley DB package, if called via its &'ndbm'& compatibility interface,
1700operates on a single file called &_dbmfile.db_&, but otherwise looks to the
1701programmer exactly the same as the traditional &'ndbm'& implementation.
1702.next
1703If the Berkeley package is used in its native mode, it operates on a single
1704file called &_dbmfile_&; the programmer's interface is somewhat different to
1705the traditional &'ndbm'& interface.
1706.next
1707To complicate things further, there are several very different versions of the
168e428f 1708Berkeley DB package. Version 1.85 was stable for a very long time, releases
9b371988
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17092.&'x'& and 3.&'x'& were current for a while, but the latest versions are now
1710numbered 4.&'x'&. Maintenance of some of the earlier releases has ceased. All
168e428f 1711versions of Berkeley DB can be obtained from
9b371988
PH
1712&url(http://www.sleepycat.com/).
1713.next
1714.cindex "&'tdb'& DBM library"
1715Yet another DBM library, called &'tdb'&, is available from
1716&url(http://download.sourceforge.net/tdb). It has its own interface, and also
1717operates on a single file.
1718.endlist
1719
1720.cindex "USE_DB"
1721.cindex "DBM libraries" "configuration for building"
168e428f
PH
1722Exim and its utilities can be compiled to use any of these interfaces. In order
1723to use any version of the Berkeley DB package in native mode, you must set
1724USE_DB in an appropriate configuration file (typically
9b371988
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1725&_Local/Makefile_&). For example:
1726.code
1727USE_DB=yes
1728.endd
168e428f
PH
1729Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
1730error is diagnosed if you set more than one of these.
1731
1732At the lowest level, the build-time configuration sets none of these options,
1733thereby assuming an interface of type (1). However, some operating system
1734configuration files (for example, those for the BSD operating systems and
1735Linux) assume type (4) by setting USE_DB as their default, and the
1736configuration files for Cygwin set USE_GDBM. Anything you set in
9b371988 1737&_Local/Makefile_&, however, overrides these system defaults.
168e428f
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1738
1739As well as setting USE_DB, USE_GDBM, or USE_TDB, it may also be
1740necessary to set DBMLIB, to cause inclusion of the appropriate library, as
1741in one of these lines:
9b371988
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1742.code
1743DBMLIB = -ldb
1744DBMLIB = -ltdb
1745.endd
168e428f
PH
1746Settings like that will work if the DBM library is installed in the standard
1747place. Sometimes it is not, and the library's header file may also not be in
1748the default path. You may need to set INCLUDE to specify where the header
1749file is, and to specify the path to the library more fully in DBMLIB, as in
1750this example:
9b371988
PH
1751.code
1752INCLUDE=-I/usr/local/include/db-4.1
1753DBMLIB=/usr/local/lib/db-4.1/libdb.a
1754.endd
168e428f 1755There is further detailed discussion about the various DBM libraries in the
9b371988 1756file &_doc/dbm.discuss.txt_& in the Exim distribution.
168e428f
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1757
1758
1759
f89d2485 1760.section "Pre-building configuration" "SECID25"
9b371988
PH
1761.cindex "building Exim" "pre-building configuration"
1762.cindex "configuration for building Exim"
1763.cindex "&_Local/Makefile_&"
1764.cindex "&_src/EDITME_&"
168e428f
PH
1765Before building Exim, a local configuration file that specifies options
1766independent of any operating system has to be created with the name
9b371988
PH
1767&_Local/Makefile_&. A template for this file is supplied as the file
1768&_src/EDITME_&, and it contains full descriptions of all the option settings
168e428f
PH
1769therein. These descriptions are therefore not repeated here. If you are
1770building Exim for the first time, the simplest thing to do is to copy
9b371988 1771&_src/EDITME_& to &_Local/Makefile_&, then read it and edit it appropriately.
168e428f
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1772
1773There are three settings that you must supply, because Exim will not build
1774without them. They are the location of the run time configuration file
1775(CONFIGURE_FILE), the directory in which Exim binaries will be installed
1776(BIN_DIRECTORY), and the identity of the Exim user (EXIM_USER and
1777maybe EXIM_GROUP as well). The value of CONFIGURE_FILE can in fact be
1778a colon-separated list of file names; Exim uses the first of them that exists.
1779
1780There are a few other parameters that can be specified either at build time or
1781at run time, to enable the same binary to be used on a number of different
1782machines. However, if the locations of Exim's spool directory and log file
1783directory (if not within the spool directory) are fixed, it is recommended that
9b371988 1784you specify them in &_Local/Makefile_& instead of at run time, so that errors
168e428f
PH
1785detected early in Exim's execution (such as a malformed configuration file) can
1786be logged.
1787
9b371988 1788.cindex "content scanning" "specifying at build time"
068aaea8 1789Exim's interfaces for calling virus and spam scanning software directly from
168e428f
PH
1790access control lists are not compiled by default. If you want to include these
1791facilities, you need to set
9b371988
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1792.code
1793WITH_CONTENT_SCAN=yes
1794.endd
1795in your &_Local/Makefile_&. For details of the facilities themselves, see
1796chapter &<<CHAPexiscan>>&.
168e428f
PH
1797
1798
9b371988 1799.cindex "&_Local/eximon.conf_&"
3cb1b51e 1800.cindex "&_exim_monitor/EDITME_&"
168e428f 1801If you are going to build the Exim monitor, a similar configuration process is
9b371988
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1802required. The file &_exim_monitor/EDITME_& must be edited appropriately for
1803your installation and saved under the name &_Local/eximon.conf_&. If you are
1804happy with the default settings described in &_exim_monitor/EDITME_&,
1805&_Local/eximon.conf_& can be empty, but it must exist.
168e428f
PH
1806
1807This is all the configuration that is needed in straightforward cases for known
1808operating systems. However, the building process is set up so that it is easy
1809to override options that are set by default or by operating-system-specific
1810configuration files, for example to change the name of the C compiler, which
9b371988
PH
1811defaults to &%gcc%&. See section &<<SECToverride>>& below for details of how to
1812do this.
168e428f
PH
1813
1814
1815
f89d2485 1816.section "Support for iconv()" "SECID26"
9b371988
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1817.cindex "&[iconv()]& support"
1818.cindex "RFC 2047"
168e428f
PH
1819The contents of header lines in messages may be encoded according to the rules
1820described RFC 2047. This makes it possible to transmit characters that are not
1821in the ASCII character set, and to label them as being in a particular
9b371988 1822character set. When Exim is inspecting header lines by means of the &%$h_%&
168e428f
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1823mechanism, it decodes them, and translates them into a specified character set
1824(default ISO-8859-1). The translation is possible only if the operating system
9b371988
PH
1825supports the &[iconv()]& function.
1826
1827However, some of the operating systems that supply &[iconv()]& do not support
1828very many conversions. The GNU &%libiconv%& library (available from
1829&url(http://www.gnu.org/software/libiconv/)) can be installed on such
1830systems to remedy this deficiency, as well as on systems that do not supply
1831&[iconv()]& at all. After installing &%libiconv%&, you should add
1832.code
1833HAVE_ICONV=yes
1834.endd
1835to your &_Local/Makefile_& and rebuild Exim.
1836
1837
1838
1839.section "Including TLS/SSL encryption support" "SECTinctlsssl"
1840.cindex "TLS" "including support for TLS"
1841.cindex "encryption" "including support for"
1842.cindex "SUPPORT_TLS"
1843.cindex "OpenSSL" "building Exim with"
1844.cindex "GnuTLS" "building Exim with"
168e428f
PH
1845Exim can be built to support encrypted SMTP connections, using the STARTTLS
1846command as per RFC 2487. It can also support legacy clients that expect to
1847start a TLS session immediately on connection to a non-standard port (see the
9b371988 1848&%tls_on_connect_ports%& runtime option and the &%-tls-on-connect%& command
168e428f
PH
1849line option).
1850
1851If you want to build Exim with TLS support, you must first install either the
1852OpenSSL or GnuTLS library. There is no cryptographic code in Exim itself for
1853implementing SSL.
1854
1855If OpenSSL is installed, you should set
9b371988
PH
1856.code
1857SUPPORT_TLS=yes
1858TLS_LIBS=-lssl -lcrypto
1859.endd
1860in &_Local/Makefile_&. You may also need to specify the locations of the
168e428f 1861OpenSSL library and include files. For example:
9b371988
PH
1862.code
1863SUPPORT_TLS=yes
1864TLS_LIBS=-L/usr/local/openssl/lib -lssl -lcrypto
1865TLS_INCLUDE=-I/usr/local/openssl/include/
1866.endd
1867.cindex "USE_GNUTLS"
168e428f 1868If GnuTLS is installed, you should set
9b371988
PH
1869.code
1870SUPPORT_TLS=yes
1871USE_GNUTLS=yes
1872TLS_LIBS=-lgnutls -ltasn1 -lgcrypt
1873.endd
1874in &_Local/Makefile_&, and again you may need to specify the locations of the
168e428f 1875library and include files. For example:
9b371988
PH
1876.code
1877SUPPORT_TLS=yes
1878USE_GNUTLS=yes
1879TLS_LIBS=-L/usr/gnu/lib -lgnutls -ltasn1 -lgcrypt
1880TLS_INCLUDE=-I/usr/gnu/include
1881.endd
168e428f 1882You do not need to set TLS_INCLUDE if the relevant directory is already
9b371988
PH
1883specified in INCLUDE. Details of how to configure Exim to make use of TLS are
1884given in chapter &<<CHAPTLS>>&.
168e428f
PH
1885
1886
1887
1888
f89d2485
PH
1889.section "Use of tcpwrappers" "SECID27"
1890.cindex "tcpwrappers, building Exim to support"
9b371988
PH
1891.cindex "USE_TCP_WRAPPERS"
1892Exim can be linked with the &'tcpwrappers'& library in order to check incoming
1893SMTP calls using the &'tcpwrappers'& control files. This may be a convenient
168e428f 1894alternative to Exim's own checking facilities for installations that are
9b371988
PH
1895already making use of &'tcpwrappers'& for other purposes. To do this, you
1896should set USE_TCP_WRAPPERS in &_Local/Makefile_&, arrange for the file
1897&_tcpd.h_& to be available at compile time, and also ensure that the library
1898&_libwrap.a_& is available at link time, typically by including &%-lwrap%& in
1899EXTRALIBS_EXIM. For example, if &'tcpwrappers'& is installed in &_/usr/local_&,
1900you might have
1901.code
1902USE_TCP_WRAPPERS=yes
1903CFLAGS=-O -I/usr/local/include
1904EXTRALIBS_EXIM=-L/usr/local/lib -lwrap
1905.endd
1906in &_Local/Makefile_&. The name to use in the &'tcpwrappers'& control files is
1907&"exim"&. For example, the line
1908.code
1909exim : LOCAL 192.168.1. .friendly.domain.example
1910.endd
1911in your &_/etc/hosts.allow_& file allows connections from the local host, from
1912the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&.
1913All other connections are denied. Consult the &'tcpwrappers'& documentation for
168e428f
PH
1914further details.
1915
1916
1917
f89d2485 1918.section "Including support for IPv6" "SECID28"
9b371988 1919.cindex "IPv6" "including support for"
168e428f 1920Exim contains code for use on systems that have IPv6 support. Setting
9b371988 1921&`HAVE_IPV6=YES`& in &_Local/Makefile_& causes the IPv6 code to be included;
168e428f
PH
1922it may also be necessary to set IPV6_INCLUDE and IPV6_LIBS on systems
1923where the IPv6 support is not fully integrated into the normal include and
1924library files.
1925
1926Two different types of DNS record for handling IPv6 addresses have been
f89d2485 1927defined. AAAA records (analogous to A records for IPv4) are in use, and are
168e428f
PH
1928currently seen as the mainstream. Another record type called A6 was proposed
1929as better than AAAA because it had more flexibility. However, it was felt to be
9b371988 1930over-complex, and its status was reduced to &"experimental"&. It is not known
168e428f 1931if anyone is actually using A6 records. Exim has support for A6 records, but
9b371988 1932this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
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1933support has not been tested for some time.
1934
1935
1936
f89d2485 1937.section "The building process" "SECID29"
9b371988
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1938.cindex "build directory"
1939Once &_Local/Makefile_& (and &_Local/eximon.conf_&, if required) have been
1940created, run &'make'& at the top level. It determines the architecture and
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1941operating system types, and creates a build directory if one does not exist.
1942For example, on a Sun system running Solaris 8, the directory
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1943&_build-SunOS5-5.8-sparc_& is created.
1944.cindex "symbolic link" "to source files"
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1945Symbolic links to relevant source files are installed in the build directory.
1946
9b371988 1947&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
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1948building process fails if it is set.
1949
9b371988 1950If this is the first time &'make'& has been run, it calls a script that builds
168e428f 1951a make file inside the build directory, using the configuration files from the
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1952&_Local_& directory. The new make file is then passed to another instance of
1953&'make'&. This does the real work, building a number of utility scripts, and
168e428f 1954then compiling and linking the binaries for the Exim monitor (if configured), a
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1955number of utility programs, and finally Exim itself. The command &`make
1956makefile`& can be used to force a rebuild of the make file in the build
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1957directory, should this ever be necessary.
1958
1959If you have problems building Exim, check for any comments there may be in the
9b371988 1960&_README_& file concerning your operating system, and also take a look at the
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1961FAQ, where some common problems are covered.
1962
1963
1964
f89d2485 1965.section 'Output from &"make"&' "SECID283"
9b371988 1966The output produced by the &'make'& process for compile lines is often very
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1967unreadable, because these lines can be very long. For this reason, the normal
1968output is suppressed by default, and instead output similar to that which
1969appears when compiling the 2.6 Linux kernel is generated: just a short line for
1970each module that is being compiled or linked. However, it is still possible to
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1971get the full output, by calling &'make'& like this:
1972.code
1973FULLECHO='' make -e
1974.endd
1975The value of FULLECHO defaults to &"@"&, the flag character that suppresses
1976command reflection in &'make'&. When you ask for the full output, it is
3cb1b51e 1977given in addition to the short output.
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1978
1979
1980
9b371988 1981.section "Overriding build-time options for Exim" "SECToverride"
f89d2485 1982.cindex "build-time options, overriding"
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1983The main make file that is created at the beginning of the building process
1984consists of the concatenation of a number of files which set configuration
9b371988 1985values, followed by a fixed set of &'make'& instructions. If a value is set
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1986more than once, the last setting overrides any previous ones. This provides a
1987convenient way of overriding defaults. The files that are concatenated are, in
1988order:
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1989.display
1990&_OS/Makefile-Default_&
1991&_OS/Makefile-_&<&'ostype'&>
1992&_Local/Makefile_&
1993&_Local/Makefile-_&<&'ostype'&>
1994&_Local/Makefile-_&<&'archtype'&>
1995&_Local/Makefile-_&<&'ostype'&>-<&'archtype'&>
1996&_OS/Makefile-Base_&
1997.endd
1998.cindex "&_Local/Makefile_&"
1999.cindex "building Exim" "operating system type"
2000.cindex "building Exim" "architecture type"
2001where <&'ostype'&> is the operating system type and <&'archtype'&> is the
2002architecture type. &_Local/Makefile_& is required to exist, and the building
2003process fails if it is absent. The other three &_Local_& files are optional,
168e428f
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2004and are often not needed.
2005
9b371988
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2006The values used for <&'ostype'&> and <&'archtype'&> are obtained from scripts
2007called &_scripts/os-type_& and &_scripts/arch-type_& respectively. If either of
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2008the environment variables EXIM_OSTYPE or EXIM_ARCHTYPE is set, their
2009values are used, thereby providing a means of forcing particular settings.
9b371988 2010Otherwise, the scripts try to get values from the &%uname%& command. If this
168e428f 2011fails, the shell variables OSTYPE and ARCHTYPE are inspected. A number
9b371988 2012of &'ad hoc'& transformations are then applied, to produce the standard names
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2013that Exim expects. You can run these scripts directly from the shell in order
2014to find out what values are being used on your system.
2015
2016
9b371988 2017&_OS/Makefile-Default_& contains comments about the variables that are set
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2018therein. Some (but not all) are mentioned below. If there is something that
2019needs changing, review the contents of this file and the contents of the make
9b371988 2020file for your operating system (&_OS/Makefile-<ostype>_&) to see what the
168e428f
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2021default values are.
2022
2023
9b371988
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2024.cindex "building Exim" "overriding default settings"
2025If you need to change any of the values that are set in &_OS/Makefile-Default_&
2026or in &_OS/Makefile-<ostype>_&, or to add any new definitions, you do not
168e428f 2027need to change the original files. Instead, you should make the changes by
9b371988
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2028putting the new values in an appropriate &_Local_& file. For example,
2029.cindex "Tru64-Unix build-time settings"
168e428f
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2030when building Exim in many releases of the Tru64-Unix (formerly Digital UNIX,
2031formerly DEC-OSF1) operating system, it is necessary to specify that the C
9b371988
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2032compiler is called &'cc'& rather than &'gcc'&. Also, the compiler must be
2033called with the option &%-std1%&, to make it recognize some of the features of
168e428f 2034Standard C that Exim uses. (Most other compilers recognize Standard C by
9b371988 2035default.) To do this, you should create a file called &_Local/Makefile-OSF1_&
168e428f 2036containing the lines
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2037.code
2038CC=cc
2039CFLAGS=-std1
2040.endd
168e428f 2041If you are compiling for just one operating system, it may be easier to put
9b371988 2042these lines directly into &_Local/Makefile_&.
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2043
2044Keeping all your local configuration settings separate from the distributed
2045files makes it easy to transfer them to new versions of Exim simply by copying
9b371988 2046the contents of the &_Local_& directory.
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2047
2048
9b371988
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2049.cindex "NIS lookup type" "including support for"
2050.cindex "NIS+ lookup type" "including support for"
2051.cindex "LDAP" "including support for"
2052.cindex "lookup" "inclusion in binary"
168e428f
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2053Exim contains support for doing LDAP, NIS, NIS+, and other kinds of file
2054lookup, but not all systems have these components installed, so the default is
2055not to include the relevant code in the binary. All the different kinds of file
2056and database lookup that Exim supports are implemented as separate code modules
2057which are included only if the relevant compile-time options are set. In the
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2058case of LDAP, NIS, and NIS+, the settings for &_Local/Makefile_& are:
2059.code
2060LOOKUP_LDAP=yes
2061LOOKUP_NIS=yes
2062LOOKUP_NISPLUS=yes
2063.endd
168e428f 2064and similar settings apply to the other lookup types. They are all listed in
9b371988 2065&_src/EDITME_&. In many cases the relevant include files and interface
168e428f 2066libraries need to be installed before compiling Exim.
9b371988 2067.cindex "cdb" "including support for"
068aaea8
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2068However, there are some optional lookup types (such as cdb) for which
2069the code is entirely contained within Exim, and no external include
168e428f
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2070files or libraries are required. When a lookup type is not included in the
2071binary, attempts to configure Exim to use it cause run time configuration
2072errors.
2073
9b371988 2074.cindex "Perl" "including support for"
168e428f
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2075Exim can be linked with an embedded Perl interpreter, allowing Perl
2076subroutines to be called during string expansion. To enable this facility,
9b371988
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2077.code
2078EXIM_PERL=perl.o
2079.endd
2080must be defined in &_Local/Makefile_&. Details of this facility are given in
2081chapter &<<CHAPperl>>&.
168e428f 2082
f89d2485 2083.cindex "X11 libraries, location of"
168e428f 2084The location of the X11 libraries is something that varies a lot between
068aaea8 2085operating systems, and there may be different versions of X11 to cope
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2086with. Exim itself makes no use of X11, but if you are compiling the Exim
2087monitor, the X11 libraries must be available.
9b371988
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2088The following three variables are set in &_OS/Makefile-Default_&:
2089.code
2090X11=/usr/X11R6
2091XINCLUDE=-I$(X11)/include
2092XLFLAGS=-L$(X11)/lib
2093.endd
168e428f 2094These are overridden in some of the operating-system configuration files. For
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2095example, in &_OS/Makefile-SunOS5_& there is
2096.code
2097X11=/usr/openwin
2098XINCLUDE=-I$(X11)/include
2099XLFLAGS=-L$(X11)/lib -R$(X11)/lib
2100.endd
168e428f
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2101If you need to override the default setting for your operating system, place a
2102definition of all three of these variables into your
9b371988 2103&_Local/Makefile-<ostype>_& file.
168e428f 2104
9b371988 2105.cindex "EXTRALIBS"
168e428f
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2106If you need to add any extra libraries to the link steps, these can be put in a
2107variable called EXTRALIBS, which appears in all the link commands, but by
2108default is not defined. In contrast, EXTRALIBS_EXIM is used only on the
2109command for linking the main Exim binary, and not for any associated utilities.
2110
9b371988 2111.cindex "DBM libraries" "configuration for building"
168e428f 2112There is also DBMLIB, which appears in the link commands for binaries that
9b371988 2113use DBM functions (see also section &<<SECTdb>>&). Finally, there is
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2114EXTRALIBS_EXIMON, which appears only in the link step for the Exim monitor
2115binary, and which can be used, for example, to include additional X11
2116libraries.
2117
9b371988 2118.cindex "configuration file" "editing"
168e428f
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2119The make file copes with rebuilding Exim correctly if any of the configuration
2120files are edited. However, if an optional configuration file is deleted, it is
9b371988
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2121necessary to touch the associated non-optional file (that is,
2122&_Local/Makefile_& or &_Local/eximon.conf_&) before rebuilding.
168e428f
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2123
2124
f89d2485 2125.section "OS-specific header files" "SECID30"
9b371988
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2126.cindex "&_os.h_&"
2127.cindex "building Exim" "OS-specific C header files"
2128The &_OS_& directory contains a number of files with names of the form
2129&_os.h-<ostype>_&. These are system-specific C header files that should not
168e428f 2130normally need to be changed. There is a list of macro settings that are
9b371988 2131recognized in the file &_OS/os.configuring_&, which should be consulted if you
168e428f
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2132are porting Exim to a new operating system.
2133
2134
2135
f89d2485
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2136.section "Overriding build-time options for the monitor" "SECID31"
2137.cindex "building Eximon"
168e428f
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2138A similar process is used for overriding things when building the Exim monitor,
2139where the files that are involved are
9b371988
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2140.display
2141&_OS/eximon.conf-Default_&
2142&_OS/eximon.conf-_&<&'ostype'&>
2143&_Local/eximon.conf_&
2144&_Local/eximon.conf-_&<&'ostype'&>
2145&_Local/eximon.conf-_&<&'archtype'&>
2146&_Local/eximon.conf-_&<&'ostype'&>-<&'archtype'&>
2147.endd
2148.cindex "&_Local/eximon.conf_&"
168e428f 2149As with Exim itself, the final three files need not exist, and in this case the
9b371988
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2150&_OS/eximon.conf-<ostype>_& file is also optional. The default values in
2151&_OS/eximon.conf-Default_& can be overridden dynamically by setting environment
168e428f
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2152variables of the same name, preceded by EXIMON_. For example, setting
2153EXIMON_LOG_DEPTH in the environment overrides the value of
2154LOG_DEPTH at run time.
4f578862 2155.ecindex IIDbuex
168e428f
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2156
2157
f89d2485 2158.section "Installing Exim binaries and scripts" "SECID32"
9b371988
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2159.cindex "installing Exim"
2160.cindex "BIN_DIRECTORY"
2161The command &`make install`& runs the &(exim_install)& script with no
2162arguments. The script copies binaries and utility scripts into the directory
2163whose name is specified by the BIN_DIRECTORY setting in &_Local/Makefile_&.
2164.cindex "setuid" "installing Exim with"
068aaea8
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2165The install script copies files only if they are newer than the files they are
2166going to replace. The Exim binary is required to be owned by root and have the
9b371988
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2167&'setuid'& bit set, for normal configurations. Therefore, you must run &`make
2168install`& as root so that it can set up the Exim binary in this way. However, in
068aaea8
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2169some special situations (for example, if a host is doing no local deliveries)
2170it may be possible to run Exim without making the binary setuid root (see
9b371988 2171chapter &<<CHAPsecurity>>& for details).
168e428f 2172
9b371988 2173.cindex "CONFIGURE_FILE"
168e428f 2174Exim's run time configuration file is named by the CONFIGURE_FILE setting
9b371988
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2175in &_Local/Makefile_&. If this names a single file, and the file does not
2176exist, the default configuration file &_src/configure.default_& is copied there
168e428f
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2177by the installation script. If a run time configuration file already exists, it
2178is left alone. If CONFIGURE_FILE is a colon-separated list, naming several
2179alternative files, no default is installed.
2180
9b371988
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2181.cindex "system aliases file"
2182.cindex "&_/etc/aliases_&"
168e428f
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2183One change is made to the default configuration file when it is installed: the
2184default configuration contains a router that references a system aliases file.
2185The path to this file is set to the value specified by
9b371988 2186SYSTEM_ALIASES_FILE in &_Local/Makefile_& (&_/etc/aliases_& by default).
168e428f
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2187If the system aliases file does not exist, the installation script creates it,
2188and outputs a comment to the user.
2189
2190The created file contains no aliases, but it does contain comments about the
2191aliases a site should normally have. Mail aliases have traditionally been
9b371988
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2192kept in &_/etc/aliases_&. However, some operating systems are now using
2193&_/etc/mail/aliases_&. You should check if yours is one of these, and change
168e428f
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2194Exim's configuration if necessary.
2195
2196The default configuration uses the local host's name as the only local domain,
9b371988
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2197and is set up to do local deliveries into the shared directory &_/var/mail_&,
2198running as the local user. System aliases and &_.forward_& files in users' home
168e428f
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2199directories are supported, but no NIS or NIS+ support is configured. Domains
2200other than the name of the local host are routed using the DNS, with delivery
2201over SMTP.
2202
168e428f
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2203It is possible to install Exim for special purposes (such as building a binary
2204distribution) in a private part of the file system. You can do this by a
2205command such as
9b371988
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2206.code
2207make DESTDIR=/some/directory/ install
2208.endd
168e428f
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2209This has the effect of pre-pending the specified directory to all the file
2210paths, except the name of the system aliases file that appears in the default
9b371988 2211configuration. (If a default alias file is created, its name &'is'& modified.)
168e428f
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2212For backwards compatibility, ROOT is used if DESTDIR is not set,
2213but this usage is deprecated.
2214
9b371988
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2215.cindex "installing Exim" "what is not installed"
2216Running &'make install'& does not copy the Exim 4 conversion script
2217&'convert4r4'&, or the &'pcretest'& test program. You will probably run the
168e428f 2218first of these only once (if you are upgrading from Exim 3), and the second
9b371988 2219isn't really part of Exim. None of the documentation files in the &_doc_&
168e428f 2220directory are copied, except for the info files when you have set
9b371988 2221INFO_DIRECTORY, as described in section &<<SECTinsinfdoc>>& below.
168e428f 2222
9b371988 2223For the utility programs, old versions are renamed by adding the suffix &_.O_&
168e428f
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2224to their names. The Exim binary itself, however, is handled differently. It is
2225installed under a name that includes the version number and the compile number,
9b371988
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2226for example &_exim-&version;-1_&. The script then arranges for a symbolic link
2227called &_exim_& to point to the binary. If you are updating a previous version
2228of Exim, the script takes care to ensure that the name &_exim_& is never absent
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2229from the directory (as seen by other processes).
2230
9b371988
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2231.cindex "installing Exim" "testing the script"
2232If you want to see what the &'make install'& will do before running it for
2233real, you can pass the &%-n%& option to the installation script by this
2234command:
2235.code
2236make INSTALL_ARG=-n install
2237.endd
168e428f
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2238The contents of the variable INSTALL_ARG are passed to the installation
2239script. You do not need to be root to run this test. Alternatively, you can run
2240the installation script directly, but this must be from within the build
2241directory. For example, from the top-level Exim directory you could use this
2242command:
9b371988
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2243.code
2244(cd build-SunOS5-5.5.1-sparc; ../scripts/exim_install -n)
2245.endd
2246.cindex "installing Exim" "install script options"
168e428f
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2247There are two other options that can be supplied to the installation script.
2248
9b371988
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2249.ilist
2250&%-no_chown%& bypasses the call to change the owner of the installed binary
168e428f 2251to root, and the call to make it a setuid binary.
9b371988
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2252.next
2253&%-no_symlink%& bypasses the setting up of the symbolic link &_exim_& to the
168e428f 2254installed binary.
9b371988 2255.endlist
168e428f
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2256
2257INSTALL_ARG can be used to pass these options to the script. For example:
9b371988
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2258.code
2259make INSTALL_ARG=-no_symlink install
2260.endd
168e428f
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2261The installation script can also be given arguments specifying which files are
2262to be copied. For example, to install just the Exim binary, and nothing else,
2263without creating the symbolic link, you could use:
9b371988
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2264.code
2265make INSTALL_ARG='-no_symlink exim' install
2266.endd
168e428f
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2267
2268
2269
9b371988
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2270.section "Installing info documentation" "SECTinsinfdoc"
2271.cindex "installing Exim" "&'info'& documentation"
2272Not all systems use the GNU &'info'& system for documentation, and for this
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2273reason, the Texinfo source of Exim's documentation is not included in the main
2274distribution. Instead it is available separately from the ftp site (see section
9b371988 2275&<<SECTavail>>&).
168e428f 2276
9b371988
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2277If you have defined INFO_DIRECTORY in &_Local/Makefile_& and the Texinfo
2278source of the documentation is found in the source tree, running &`make
2279install`& automatically builds the info files and installs them.
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2280
2281
2282
f89d2485 2283.section "Setting up the spool directory" "SECID33"
9b371988 2284.cindex "spool directory" "creating"
168e428f
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2285When it starts up, Exim tries to create its spool directory if it does not
2286exist. The Exim uid and gid are used for the owner and group of the spool
2287directory. Sub-directories are automatically created in the spool directory as
2288necessary.
2289
2290
2291
2292
f89d2485 2293.section "Testing" "SECID34"
9b371988 2294.cindex "testing" "installation"
168e428f
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2295Having installed Exim, you can check that the run time configuration file is
2296syntactically valid by running the following command, which assumes that the
2297Exim binary directory is within your PATH environment variable:
9b371988
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2298.code
2299exim -bV
2300.endd
168e428f
PH
2301If there are any errors in the configuration file, Exim outputs error messages.
2302Otherwise it outputs the version number and build date,
2303the DBM library that is being used, and information about which drivers and
2304other optional code modules are included in the binary.
2305Some simple routing tests can be done by using the address testing option. For
2306example,
9b371988
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2307.display
2308&`exim -bt`& <&'local username'&>
2309.endd
168e428f 2310should verify that it recognizes a local mailbox, and
9b371988
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2311.display
2312&`exim -bt`& <&'remote address'&>
2313.endd
168e428f
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2314a remote one. Then try getting it to deliver mail, both locally and remotely.
2315This can be done by passing messages directly to Exim, without going through a
2316user agent. For example:
9b371988 2317.code
068aaea8
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2318exim -v postmaster@your.domain.example
2319From: user@your.domain.example
2320To: postmaster@your.domain.example
2321Subject: Testing Exim
168e428f 2322
068aaea8
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2323This is a test message.
2324^D
9b371988
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2325.endd
2326The &%-v%& option causes Exim to output some verification of what it is doing.
168e428f 2327In this case you should see copies of three log lines, one for the message's
9b371988 2328arrival, one for its delivery, and one containing &"Completed"&.
168e428f 2329
9b371988
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2330.cindex "delivery" "problems with"
2331If you encounter problems, look at Exim's log files (&'mainlog'& and
2332&'paniclog'&) to see if there is any relevant information there. Another source
168e428f 2333of information is running Exim with debugging turned on, by specifying the
9b371988 2334&%-d%& option. If a message is stuck on Exim's spool, you can force a delivery
168e428f 2335with debugging turned on by a command of the form
9b371988
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2336.display
2337&`exim -d -M`& <&'exim-message-id'&>
2338.endd
2339You must be root or an &"admin user"& in order to do this. The &%-d%& option
168e428f 2340produces rather a lot of output, but you can cut this down to specific areas.
9b371988
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2341For example, if you use &%-d-all+route%& only the debugging information
2342relevant to routing is included. (See the &%-d%& option in chapter
2343&<<CHAPcommandline>>& for more details.)
168e428f 2344
9b371988
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2345.cindex '&"sticky"& bit'
2346.cindex "lock files"
168e428f
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2347One specific problem that has shown up on some sites is the inability to do
2348local deliveries into a shared mailbox directory, because it does not have the
9b371988 2349&"sticky bit"& set on it. By default, Exim tries to create a lock file before
168e428f 2350writing to a mailbox file, and if it cannot create the lock file, the delivery
9b371988 2351is deferred. You can get round this either by setting the &"sticky bit"& on the
168e428f
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2352directory, or by setting a specific group for local deliveries and allowing
2353that group to create files in the directory (see the comments above the
9b371988 2354&(local_delivery)& transport in the default configuration file). Another
168e428f 2355approach is to configure Exim not to use lock files, but just to rely on
9b371988
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2356&[fcntl()]& locking instead. However, you should do this only if all user
2357agents also use &[fcntl()]& locking. For further discussion of locking issues,
2358see chapter &<<CHAPappendfile>>&.
168e428f
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2359
2360One thing that cannot be tested on a system that is already running an MTA is
2361the receipt of incoming SMTP mail on the standard SMTP port. However, the
9b371988
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2362&%-oX%& option can be used to run an Exim daemon that listens on some other
2363port, or &'inetd'& can be used to do this. The &%-bh%& option and the
2364&'exim_checkaccess'& utility can be used to check out policy controls on
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2365incoming SMTP mail.
2366
2367Testing a new version on a system that is already running Exim can most easily
2368be done by building a binary with a different CONFIGURE_FILE setting. From
2369within the run time configuration, all other file and directory names
2370that Exim uses can be altered, in order to keep it entirely clear of the
2371production version.
2372
2373
f89d2485 2374.section "Replacing another MTA with Exim" "SECID35"
9b371988 2375.cindex "replacing another MTA"
168e428f
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2376Building and installing Exim for the first time does not of itself put it in
2377general use. The name by which the system's MTA is called by mail user agents
9b371988
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2378is either &_/usr/sbin/sendmail_&, or &_/usr/lib/sendmail_& (depending on the
2379operating system), and it is necessary to make this name point to the &'exim'&
168e428f 2380binary in order to get the user agents to pass messages to Exim. This is
9b371988
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2381normally done by renaming any existing file and making &_/usr/sbin/sendmail_&
2382or &_/usr/lib/sendmail_&
2383.cindex "symbolic link" "to &'exim'& binary"
2384a symbolic link to the &'exim'& binary. It is a good idea to remove any setuid
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2385privilege and executable status from the old MTA. It is then necessary to stop
2386and restart the mailer daemon, if one is running.
2387
f89d2485 2388.cindex "FreeBSD, MTA indirection"
9b371988 2389.cindex "&_/etc/mail/mailer.conf_&"
168e428f
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2390Some operating systems have introduced alternative ways of switching MTAs. For
2391example, if you are running FreeBSD, you need to edit the file
9b371988 2392&_/etc/mail/mailer.conf_& instead of setting up a symbolic link as just
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2393described. A typical example of the contents of this file for running Exim is
2394as follows:
9b371988
PH
2395.code
2396sendmail /usr/exim/bin/exim
2397send-mail /usr/exim/bin/exim
2398mailq /usr/exim/bin/exim -bp
2399newaliases /usr/bin/true
2400.endd
2401Once you have set up the symbolic link, or edited &_/etc/mail/mailer.conf_&,
2402your Exim installation is &"live"&. Check it by sending a message from your
168e428f
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2403favourite user agent.
2404
2405You should consider what to tell your users about the change of MTA. Exim may
2406have different capabilities to what was previously running, and there are
2407various operational differences such as the text of messages produced by
2408command line options and in bounce messages. If you allow your users to make
2409use of Exim's filtering capabilities, you should make the document entitled
9b371988 2410&'Exim's interface to mail filtering'& available to them.
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2411
2412
2413
f89d2485 2414.section "Upgrading Exim" "SECID36"
9b371988 2415.cindex "upgrading Exim"
168e428f
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2416If you are already running Exim on your host, building and installing a new
2417version automatically makes it available to MUAs, or any other programs that
2418call the MTA directly. However, if you are running an Exim daemon, you do need
9b371988
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2419to send it a HUP signal, to make it re-execute itself, and thereby pick up the
2420new binary. You do not need to stop processing mail in order to install a new
068aaea8
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2421version of Exim. The install script does not modify an existing runtime
2422configuration file.
2423
168e428f
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2424
2425
2426
f89d2485 2427.section "Stopping the Exim daemon on Solaris" "SECID37"
9b371988 2428.cindex "Solaris" "stopping Exim on"
168e428f 2429The standard command for stopping the mailer daemon on Solaris is
9b371988
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2430.code
2431/etc/init.d/sendmail stop
2432.endd
2433If &_/usr/lib/sendmail_& has been turned into a symbolic link, this script
2434fails to stop Exim because it uses the command &'ps -e'& and greps the output
2435for the text &"sendmail"&; this is not present because the actual program name
2436(that is, &"exim"&) is given by the &'ps'& command with these options. A
2437solution is to replace the line that finds the process id with something like
2438.code
2439pid=`cat /var/spool/exim/exim-daemon.pid`
2440.endd
168e428f
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2441to obtain the daemon's pid directly from the file that Exim saves it in.
2442
9b371988 2443Note, however, that stopping the daemon does not &"stop Exim"&. Messages can
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2444still be received from local processes, and if automatic delivery is configured
2445(the normal case), deliveries will still occur.
2446
2447
2448
2449
9b371988
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2450. ////////////////////////////////////////////////////////////////////////////
2451. ////////////////////////////////////////////////////////////////////////////
168e428f 2452
9b371988 2453.chapter "The Exim command line" "CHAPcommandline"
4f578862
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2454.scindex IIDclo1 "command line" "options"
2455.scindex IIDclo2 "options" "command line"
168e428f
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2456Exim's command line takes the standard Unix form of a sequence of options,
2457each starting with a hyphen character, followed by a number of arguments. The
2458options are compatible with the main options of Sendmail, and there are also
2459some additional options, some of which are compatible with Smail 3. Certain
2460combinations of options do not make sense, and provoke an error if used.
2461The form of the arguments depends on which options are set.
2462
2463
f89d2485 2464.section "Setting options by program name" "SECID38"
9b371988
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2465.cindex "&'mailq'&"
2466If Exim is called under the name &'mailq'&, it behaves as if the option &%-bp%&
168e428f 2467were present before any other options.
9b371988 2468The &%-bp%& option requests a listing of the contents of the mail queue on the
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2469standard output.
2470This feature is for compatibility with some systems that contain a command of
2471that name in one of the standard libraries, symbolically linked to
9b371988
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2472&_/usr/sbin/sendmail_& or &_/usr/lib/sendmail_&.
2473
2474.cindex "&'rsmtp'&"
2475If Exim is called under the name &'rsmtp'& it behaves as if the option &%-bS%&
2476were present before any other options, for compatibility with Smail. The
2477&%-bS%& option is used for reading in a number of messages in batched SMTP
2478format.
2479
2480.cindex "&'rmail'&"
2481If Exim is called under the name &'rmail'& it behaves as if the &%-i%& and
2482&%-oee%& options were present before any other options, for compatibility with
2483Smail. The name &'rmail'& is used as an interface by some UUCP systems.
2484
2485.cindex "&'runq'&"
2486.cindex "queue runner"
2487If Exim is called under the name &'runq'& it behaves as if the option &%-q%&
2488were present before any other options, for compatibility with Smail. The &%-q%&
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2489option causes a single queue runner process to be started.
2490
9b371988
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2491.cindex "&'newaliases'&"
2492.cindex "alias file" "building"
2493.cindex "Sendmail compatibility" "calling Exim as &'newaliases'&"
2494If Exim is called under the name &'newaliases'& it behaves as if the option
2495&%-bi%& were present before any other options, for compatibility with Sendmail.
168e428f
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2496This option is used for rebuilding Sendmail's alias file. Exim does not have
2497the concept of a single alias file, but can be configured to run a given
9b371988 2498command if called with the &%-bi%& option.
168e428f
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2499
2500
9b371988
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2501.section "Trusted and admin users" "SECTtrustedadmin"
2502Some Exim options are available only to &'trusted users'& and others are
2503available only to &'admin users'&. In the description below, the phrases &"Exim
2504user"& and &"Exim group"& mean the user and group defined by EXIM_USER and
2505EXIM_GROUP in &_Local/Makefile_& or set by the &%exim_user%& and
2506&%exim_group%& options. These do not necessarily have to use the name &"exim"&.
168e428f 2507
9b371988 2508.ilist
f89d2485 2509.cindex "trusted users" "definition of"
9b371988 2510.cindex "user" "trusted definition of"
168e428f 2511The trusted users are root, the Exim user, any user listed in the
9b371988
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2512&%trusted_users%& configuration option, and any user whose current group or any
2513supplementary group is one of those listed in the &%trusted_groups%&
168e428f 2514configuration option. Note that the Exim group is not automatically trusted.
9b371988
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2515
2516.cindex '&"From"& line'
2517.cindex "envelope sender"
2518Trusted users are always permitted to use the &%-f%& option or a leading
2519&"From&~"& line to specify the envelope sender of a message that is passed to
2520Exim through the local interface (see the &%-bm%& and &%-f%& options below).
2521See the &%untrusted_set_sender%& option for a way of permitting non-trusted
2522users to set envelope senders.
2523
2524.cindex "&'From:'& header line"
2525.cindex "&'Sender:'& header line"
2526For a trusted user, there is never any check on the contents of the &'From:'&
2527header line, and a &'Sender:'& line is never added. Furthermore, any existing
2528&'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
2529
168e428f
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2530Trusted users may also specify a host name, host address, interface address,
2531protocol name, ident value, and authentication data when submitting a message
2532locally. Thus, they are able to insert messages into Exim's queue locally that
2533have the characteristics of messages received from a remote host. Untrusted
9b371988 2534users may in some circumstances use &%-f%&, but can never set the other values
168e428f 2535that are available to trusted users.
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2536.next
2537.cindex "user" "admin definition of"
2538.cindex "admin user" "definition of"
168e428f 2539The admin users are root, the Exim user, and any user that is a member of the
9b371988 2540Exim group or of any group listed in the &%admin_groups%& configuration option.
168e428f 2541The current group does not have to be one of these groups.
9b371988 2542
168e428f
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2543Admin users are permitted to list the queue, and to carry out certain
2544operations on messages, for example, to force delivery failures. It is also
2545necessary to be an admin user in order to see the full information provided by
2546the Exim monitor, and full debugging output.
9b371988
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2547
2548By default, the use of the &%-M%&, &%-q%&, &%-R%&, and &%-S%& options to cause
2549Exim to attempt delivery of messages on its queue is restricted to admin users.
2550However, this restriction can be relaxed by setting the &%prod_requires_admin%&
2551option false (that is, specifying &%no_prod_requires_admin%&).
2552
2553Similarly, the use of the &%-bp%& option to list all the messages in the queue
2554is restricted to admin users unless &%queue_list_requires_admin%& is set
168e428f 2555false.
9b371988 2556.endlist
168e428f
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2557
2558
9b371988 2559&*Warning*&: If you configure your system so that admin users are able to
168e428f
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2560edit Exim's configuration file, you are giving those users an easy way of
2561getting root. There is further discussion of this issue at the start of chapter
9b371988 2562&<<CHAPconf>>&.
168e428f
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2563
2564
2565
2566
f89d2485 2567.section "Command line options" "SECID39"
db9452a9
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2568Exim's command line options are described in alphabetical order below. If none
2569of the options that specifies a specific action (such as starting the daemon or
2570a queue runner, or testing an address, or receiving a message in a specific
2571format, or listing the queue) are present, and there is at least one argument
2572on the command line, &%-bm%& (accept a local message on the standard input,
2573with the arguments specifying the recipients) is assumed. Otherwise, Exim
2574outputs a brief message about itself and exits.
168e428f 2575
9b371988
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2576. ////////////////////////////////////////////////////////////////////////////
2577. Insert a stylized XML comment here, to identify the start of the command line
2578. options. This is for the benefit of the Perl script that automatically
2579. creates a man page for the options.
2580. ////////////////////////////////////////////////////////////////////////////
168e428f 2581
9b371988 2582.literal xml
168e428f 2583<!-- === Start of command line options === -->
9b371988 2584.literal off
168e428f
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2585
2586
9b371988
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2587.vlist
2588.vitem &%--%&
2589.oindex "--"
2590.cindex "options" "command line; terminating"
168e428f
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2591This is a pseudo-option whose only purpose is to terminate the options and
2592therefore to cause subsequent command line items to be treated as arguments
2593rather than options, even if they begin with hyphens.
2594
9b371988
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2595.vitem &%--help%&
2596.oindex "&%--help%&"
168e428f
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2597This option causes Exim to output a few sentences stating what it is.
2598The same output is generated if the Exim binary is called with no options and
2599no arguments.
2600
9b371988
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2601.vitem &%-B%&<&'type'&>
2602.oindex "&%-B%&"
2603.cindex "8-bit characters"
2604.cindex "Sendmail compatibility" "8-bit characters"
168e428f
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2605This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
2606clean; it ignores this option.
2607
9b371988
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2608.vitem &%-bd%&
2609.oindex "&%-bd%&"
2610.cindex "daemon"
f89d2485 2611.cindex "SMTP" "listener"
9b371988 2612.cindex "queue runner"
168e428f 2613This option runs Exim as a daemon, awaiting incoming SMTP connections. Usually
9b371988
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2614the &%-bd%& option is combined with the &%-q%&<&'time'&> option, to specify
2615that the daemon should also initiate periodic queue runs.
2616
2617The &%-bd%& option can be used only by an admin user. If either of the &%-d%&
2618(debugging) or &%-v%& (verifying) options are set, the daemon does not
168e428f
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2619disconnect from the controlling terminal. When running this way, it can be
2620stopped by pressing ctrl-C.
9b371988 2621
168e428f
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2622By default, Exim listens for incoming connections to the standard SMTP port on
2623all the host's running interfaces. However, it is possible to listen on other
2624ports, on multiple ports, and only on specific interfaces. Chapter
9b371988
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2625&<<CHAPinterfaces>>& contains a description of the options that control this.
2626
168e428f 2627When a listening daemon
9b371988
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2628.cindex "daemon" "process id (pid)"
2629.cindex "pid (process id)" "of daemon"
2630is started without the use of &%-oX%& (that is, without overriding the normal
2631configuration), it writes its process id to a file called &_exim-daemon.pid_&
2632in Exim's spool directory. This location can be overridden by setting
2633PID_FILE_PATH in &_Local/Makefile_&. The file is written while Exim is still
168e428f 2634running as root.
9b371988
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2635
2636When &%-oX%& is used on the command line to start a listening daemon, the
2637process id is not written to the normal pid file path. However, &%-oP%& can be
168e428f 2638used to specify a path on the command line if a pid file is required.
9b371988 2639
168e428f 2640The SIGHUP signal
9b371988 2641.cindex "SIGHUP"
3cb1b51e
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2642.cindex "daemon" "restarting"
2643can be used to cause the daemon to re-execute itself. This should be done
2644whenever Exim's configuration file, or any file that is incorporated into it by
2645means of the &%.include%& facility, is changed, and also whenever a new version
2646of Exim is installed. It is not necessary to do this when other files that are
9b371988
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2647referenced from the configuration (for example, alias files) are changed,
2648because these are reread each time they are used.
2649
2650.vitem &%-bdf%&
2651.oindex "&%-bdf%&"
2652This option has the same effect as &%-bd%& except that it never disconnects
2653from the controlling terminal, even when no debugging is specified.
2654
2655.vitem &%-be%&
2656.oindex "&%-be%&"
2657.cindex "testing" "string expansion"
2658.cindex "expansion" "testing"
168e428f
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2659Run Exim in expansion testing mode. Exim discards its root privilege, to
2660prevent ordinary users from using this mode to read otherwise inaccessible
2661files. If no arguments are given, Exim runs interactively, prompting for lines
4f578862 2662of data. Otherwise, it processes each argument in turn.
9b371988
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2663
2664If Exim was built with USE_READLINE=yes in &_Local/Makefile_&, it tries
2665to load the &%libreadline%& library dynamically whenever the &%-be%& option is
2666used without command line arguments. If successful, it uses the &[readline()]&
168e428f
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2667function, which provides extensive line-editing facilities, for reading the
2668test data. A line history is supported.
9b371988 2669
168e428f 2670Long expansion expressions can be split over several lines by using backslash
068aaea8 2671continuations. As in Exim's run time configuration, white space at the start of
168e428f
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2672continuation lines is ignored. Each argument or data line is passed through the
2673string expansion mechanism, and the result is output. Variable values from the
9b371988 2674configuration file (for example, &$qualify_domain$&) are available, but no
3cb1b51e 2675message-specific values (such as &$sender_domain$&) are set, because no message
f89d2485 2676is being processed (but see &%-bem%& and &%-Mset%&).
168e428f 2677
9b371988
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2678&*Note*&: If you use this mechanism to test lookups, and you change the data
2679files or databases you are using, you must exit and restart Exim before trying
2680the same lookup again. Otherwise, because each Exim process caches the results
2681of lookups, you will just get the same result as before.
9b371988 2682
3cb1b51e
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2683.vitem &%-bem%&&~<&'filename'&>
2684.oindex "&%-bem%&"
2685.cindex "testing" "string expansion"
2686.cindex "expansion" "testing"
2687This option operates like &%-be%& except that it must be followed by the name
2688of a file. For example:
2689.code
2690exim -bem /tmp/testmessage
2691.endd
2692The file is read as a message (as if receiving a locally-submitted non-SMTP
2693message) before any of the test expansions are done. Thus, message-specific
2694variables such as &$message_size$& and &$header_from:$& are available. However,
2695no &'Received:'& header is added to the message. If the &%-t%& option is set,
2696recipients are read from the headers in the normal way, and are shown in the
2697&$recipients$& variable. Note that recipients cannot be given on the command
2698line, because further arguments are taken as strings to expand (just like
2699&%-be%&).
3cb1b51e 2700
9b371988
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2701.vitem &%-bF%&&~<&'filename'&>
2702.oindex "&%-bF%&"
2703.cindex "system filter" "testing"
2704.cindex "testing" "system filter"
2705This option is the same as &%-bf%& except that it assumes that the filter being
168e428f
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2706tested is a system filter. The additional commands that are available only in
2707system filters are recognized.
2708
9b371988
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2709.vitem &%-bf%&&~<&'filename'&>
2710.oindex "&%-bf%&"
2711.cindex "filter" "testing"
2712.cindex "testing" "filter file"
2713.cindex "forward file" "testing"
2714.cindex "testing" "forward file"
2715.cindex "Sieve filter" "testing"
168e428f
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2716This option runs Exim in user filter testing mode; the file is the filter file
2717to be tested, and a test message must be supplied on the standard input. If
2718there are no message-dependent tests in the filter, an empty file can be
2719supplied.
168e428f 2720
9b371988
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2721If you want to test a system filter file, use &%-bF%& instead of &%-bf%&. You
2722can use both &%-bF%& and &%-bf%& on the same command, in order to test a system
2723filter and a user filter in the same run. For example:
2724.code
2725exim -bF /system/filter -bf /user/filter </test/message
2726.endd
168e428f
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2727This is helpful when the system filter adds header lines or sets filter
2728variables that are used by the user filter.
168e428f 2729
9b371988
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2730If the test filter file does not begin with one of the special lines
2731.code
2732# Exim filter
2733# Sieve filter
2734.endd
2735it is taken to be a normal &_.forward_& file, and is tested for validity under
2736that interpretation. See sections &<<SECTitenonfilred>>& to
2737&<<SECTspecitredli>>& for a description of the possible contents of non-filter
2738redirection lists.
2739
2740The result of an Exim command that uses &%-bf%&, provided no errors are
168e428f
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2741detected, is a list of the actions that Exim would try to take if presented
2742with the message for real. More details of filter testing are given in the
9b371988
PH
2743separate document entitled &'Exim's interfaces to mail filtering'&.
2744
168e428f 2745When testing a filter file,
9b371988
PH
2746.cindex "&""From""& line"
2747.cindex "envelope sender"
f89d2485 2748.oindex "&%-f%&" "for filter testing"
9b371988
PH
2749the envelope sender can be set by the &%-f%& option,
2750or by a &"From&~"& line at the start of the test message. Various parameters
2751that would normally be taken from the envelope recipient address of the message
2752can be set by means of additional command line options (see the next four
2753options).
2754
2755.vitem &%-bfd%&&~<&'domain'&>
2756.oindex "&%-bfd%&"
f89d2485 2757.vindex "&$qualify_domain$&"
168e428f 2758This sets the domain of the recipient address when a filter file is being
9b371988
PH
2759tested by means of the &%-bf%& option. The default is the value of
2760&$qualify_domain$&.
168e428f 2761
9b371988
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2762.vitem &%-bfl%&&~<&'local&~part'&>
2763.oindex "&%-bfl%&"
168e428f 2764This sets the local part of the recipient address when a filter file is being
9b371988 2765tested by means of the &%-bf%& option. The default is the username of the
168e428f
PH
2766process that calls Exim. A local part should be specified with any prefix or
2767suffix stripped, because that is how it appears to the filter when a message is
2768actually being delivered.
2769
9b371988
PH
2770.vitem &%-bfp%&&~<&'prefix'&>
2771.oindex "&%-bfp%&"
168e428f 2772This sets the prefix of the local part of the recipient address when a filter
9b371988 2773file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
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2774prefix.
2775
9b371988
PH
2776.vitem &%-bfs%&&~<&'suffix'&>
2777.oindex "&%-bfs%&"
168e428f 2778This sets the suffix of the local part of the recipient address when a filter
9b371988 2779file is being tested by means of the &%-bf%& option. The default is an empty
168e428f
PH
2780suffix.
2781
9b371988
PH
2782.vitem &%-bh%&&~<&'IP&~address'&>
2783.oindex "&%-bh%&"
2784.cindex "testing" "incoming SMTP"
2785.cindex "SMTP" "testing incoming"
2786.cindex "testing" "relay control"
2787.cindex "relaying" "testing configuration"
2788.cindex "policy control" "testing"
2789.cindex "debugging" "&%-bh%& option"
168e428f
PH
2790This option runs a fake SMTP session as if from the given IP address, using the
2791standard input and output. The IP address may include a port number at the end,
2792after a full stop. For example:
9b371988
PH
2793.code
2794exim -bh 10.9.8.7.1234
2795exim -bh fe80::a00:20ff:fe86:a061.5678
2796.endd
168e428f 2797When an IPv6 address is given, it is converted into canonical form. In the case
9b371988
PH
2798of the second example above, the value of &$sender_host_address$& after
2799conversion to the canonical form is
2800&`fe80:0000:0000:0a00:20ff:fe86:a061.5678`&.
2801
168e428f 2802Comments as to what is going on are written to the standard error file. These
9b371988 2803include lines beginning with &"LOG"& for anything that would have been logged.
168e428f
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2804This facility is provided for testing configuration options for incoming
2805messages, to make sure they implement the required policy. For example, you can
9b371988
PH
2806test your relay controls using &%-bh%&.
2807
2808&*Warning 1*&:
2809.cindex "RFC 1413"
db9452a9
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2810You can test features of the configuration that rely on ident (RFC 1413)
2811information by using the &%-oMt%& option. However, Exim cannot actually perform
2812an ident callout when testing using &%-bh%& because there is no incoming SMTP
2813connection.
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2814
2815&*Warning 2*&: Address verification callouts (see section &<<SECTcallver>>&)
2816are also skipped when testing using &%-bh%&. If you want these callouts to
2817occur, use &%-bhc%& instead.
2818
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2819Messages supplied during the testing session are discarded, and nothing is
2820written to any of the real log files. There may be pauses when DNS (and other)
9b371988 2821lookups are taking place, and of course these may time out. The &%-oMi%& option
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2822can be used to specify a specific IP interface and port if this is important,
2823and &%-oMaa%& and &%-oMai%& can be used to set parameters as if the SMTP
2824session were authenticated.
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2825
2826The &'exim_checkaccess'& utility is a &"packaged"& version of &%-bh%& whose
168e428f 2827output just states whether a given recipient address from a given host is
9b371988 2828acceptable or not. See section &<<SECTcheckaccess>>&.
168e428f 2829
3cb1b51e
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2830.new
2831Features such as authentication and encryption, where the client input is not
f89d2485
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2832plain text, cannot easily be tested with &%-bh%&. Instead, you should use a
2833specialized SMTP test program such as
3cb1b51e
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2834&url(http://jetmore.org/john/code/#swaks,swaks).
2835.wen
2836
9b371988
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2837.vitem &%-bhc%&&~<&'IP&~address'&>
2838.oindex "&%-bhc%&"
2839This option operates in the same way as &%-bh%&, except that address
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2840verification callouts are performed if required. This includes consulting and
2841updating the callout cache database.
2842
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2843.vitem &%-bi%&
2844.oindex "&%-bi%&"
2845.cindex "alias file" "building"
2846.cindex "building alias file"
2847.cindex "Sendmail compatibility" "&%-bi%& option"
2848Sendmail interprets the &%-bi%& option as a request to rebuild its alias file.
168e428f 2849Exim does not have the concept of a single alias file, and so it cannot mimic
9b371988 2850this behaviour. However, calls to &_/usr/lib/sendmail_& with the &%-bi%& option
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2851tend to appear in various scripts such as NIS make files, so the option must be
2852recognized.
9b371988
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2853
2854If &%-bi%& is encountered, the command specified by the &%bi_command%&
168e428f 2855configuration option is run, under the uid and gid of the caller of Exim. If
9b371988
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2856the &%-oA%& option is used, its value is passed to the command as an argument.
2857The command set by &%bi_command%& may not contain arguments. The command can
2858use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
2859if this is required. If the &%bi_command%& option is not set, calling Exim with
2860&%-bi%& is a no-op.
2861
2862.vitem &%-bm%&
2863.oindex "&%-bm%&"
2864.cindex "local message reception"
168e428f
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2865This option runs an Exim receiving process that accepts an incoming,
2866locally-generated message on the current input. The recipients are given as the
9b371988 2867command arguments (except when &%-t%& is also present &-- see below). Each
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2868argument can be a comma-separated list of RFC 2822 addresses. This is the
2869default option for selecting the overall action of an Exim call; it is assumed
2870if no other conflicting option is present.
9b371988 2871
168e428f 2872If any addresses in the message are unqualified (have no domain), they are
9b371988
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2873qualified by the values of the &%qualify_domain%& or &%qualify_recipient%&
2874options, as appropriate. The &%-bnq%& option (see below) provides a way of
168e428f 2875suppressing this for special cases.
9b371988 2876
168e428f 2877Policy checks on the contents of local messages can be enforced by means of
9b371988
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2878the non-SMTP ACL. See chapter &<<CHAPACL>>& for details.
2879
2880.cindex "return code" "for &%-bm%&"
2881The return code is zero if the message is successfully accepted. Otherwise, the
2882action is controlled by the &%-oe%&&'x'& option setting &-- see below.
2883
168e428f 2884The format
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2885.cindex "message" "format"
2886.cindex "format" "message"
2887.cindex "&""From""& line"
2888.cindex "UUCP" "&""From""& line"
2889.cindex "Sendmail compatibility" "&""From""& line"
168e428f
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2890of the message must be as defined in RFC 2822, except that, for
2891compatibility with Sendmail and Smail, a line in one of the forms
9b371988
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2892.code
2893From sender Fri Jan 5 12:55 GMT 1997
2894From sender Fri, 5 Jan 97 12:55:01
2895.endd
168e428f
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2896(with the weekday optional, and possibly with additional text after the date)
2897is permitted to appear at the start of the message. There appears to be no
2898authoritative specification of the format of this line. Exim recognizes it by
9b371988 2899matching against the regular expression defined by the &%uucp_from_pattern%&
168e428f 2900option, which can be changed if necessary.
9b371988 2901
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2902.oindex "&%-f%&" "overriding &""From""& line"
2903The specified sender is treated as if it were given as the argument to the
9b371988 2904&%-f%& option, but if a &%-f%& option is also present, its argument is used in
168e428f
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2905preference to the address taken from the message. The caller of Exim must be a
2906trusted user for the sender of a message to be set in this way.
2907
9b371988
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2908.vitem &%-bnq%&
2909.oindex "&%-bnq%&"
f89d2485 2910.cindex "address qualification, suppressing"
168e428f
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2911By default, Exim automatically qualifies unqualified addresses (those
2912without domains) that appear in messages that are submitted locally (that
2913is, not over TCP/IP). This qualification applies both to addresses in
2914envelopes, and addresses in header lines. Sender addresses are qualified using
9b371988
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2915&%qualify_domain%&, and recipient addresses using &%qualify_recipient%& (which
2916defaults to the value of &%qualify_domain%&).
2917
2918Sometimes, qualification is not wanted. For example, if &%-bS%& (batch SMTP) is
168e428f
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2919being used to re-submit messages that originally came from remote hosts after
2920content scanning, you probably do not want to qualify unqualified addresses in
2921header lines. (Such lines will be present only if you have not enabled a header
2922syntax check in the appropriate ACL.)
9b371988
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2923
2924The &%-bnq%& option suppresses all qualification of unqualified addresses in
168e428f
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2925messages that originate on the local host. When this is used, unqualified
2926addresses in the envelope provoke errors (causing message rejection) and
2927unqualified addresses in header lines are left alone.
2928
2929
9b371988
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2930.vitem &%-bP%&
2931.oindex "&%-bP%&"
f89d2485 2932.cindex "configuration options, extracting"
9b371988 2933.cindex "options" "configuration &-- extracting"
168e428f
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2934If this option is given with no arguments, it causes the values of all Exim's
2935main configuration options to be written to the standard output. The values
2936of one or more specific options can be requested by giving their names as
2937arguments, for example:
9b371988
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2938.code
2939exim -bP qualify_domain hold_domains
2940.endd
86058a4a 2941.oindex "&%hide%&"
9b371988 2942However, any option setting that is preceded by the word &"hide"& in the
168e428f
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2943configuration file is not shown in full, except to an admin user. For other
2944users, the output is as in this example:
9b371988
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2945.code
2946mysql_servers = <value not displayable>
2947.endd
2948If &%configure_file%& is given as an argument, the name of the run time
168e428f
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2949configuration file is output.
2950If a list of configuration files was supplied, the value that is output here
2951is the name of the file that was actually used.
168e428f 2952
9b371988
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2953.cindex "daemon" "process id (pid)"
2954.cindex "pid (process id)" "of daemon"
2955If &%log_file_path%& or &%pid_file_path%& are given, the names of the
2956directories where log files and daemon pid files are written are output,
2957respectively. If these values are unset, log files are written in a
2958sub-directory of the spool directory called &%log%&, and the pid file is
2959written directly into the spool directory.
2960
2961If &%-bP%& is followed by a name preceded by &`+`&, for example,
2962.code
2963exim -bP +local_domains
2964.endd
168e428f
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2965it searches for a matching named list of any type (domain, host, address, or
2966local part) and outputs what it finds.
9b371988
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2967
2968.cindex "options" "router &-- extracting"
2969.cindex "options" "transport &-- extracting"
2970If one of the words &%router%&, &%transport%&, or &%authenticator%& is given,
168e428f
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2971followed by the name of an appropriate driver instance, the option settings for
2972that driver are output. For example:
9b371988
PH
2973.code
2974exim -bP transport local_delivery
2975.endd
168e428f
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2976The generic driver options are output first, followed by the driver's private
2977options. A list of the names of drivers of a particular type can be obtained by
9b371988
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2978using one of the words &%router_list%&, &%transport_list%&, or
2979&%authenticator_list%&, and a complete list of all drivers with their option
2980settings can be obtained by using &%routers%&, &%transports%&, or
2981&%authenticators%&.
168e428f
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2982
2983
9b371988
PH
2984.vitem &%-bp%&
2985.oindex "&%-bp%&"
2986.cindex "queue" "listing messages on"
2987.cindex "listing" "messages on the queue"
168e428f 2988This option requests a listing of the contents of the mail queue on the
9b371988 2989standard output. If the &%-bp%& option is followed by a list of message ids,
168e428f 2990just those messages are listed. By default, this option can be used only by an
9b371988 2991admin user. However, the &%queue_list_requires_admin%& option can be set false
168e428f 2992to allow any user to see the queue.
168e428f 2993
9b371988
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2994Each message on the queue is displayed as in the following example:
2995.code
299625m 2.9K 0t5C6f-0000c8-00 <alice@wonderland.fict.example>
2997 red.king@looking-glass.fict.example
2998 <other addresses>
2999.endd
3000.cindex "message" "size in queue listing"
3001.cindex "size" "of message"
3002The first line contains the length of time the message has been on the queue
168e428f
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3003(in this case 25 minutes), the size of the message (2.9K), the unique local
3004identifier for the message, and the message sender, as contained in the
3005envelope. For bounce messages, the sender address is empty, and appears as
9b371988 3006&"<>"&. If the message was submitted locally by an untrusted user who overrode
168e428f
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3007the default sender address, the user's login name is shown in parentheses
3008before the sender address.
9b371988
PH
3009
3010.cindex "frozen messages" "in queue listing"
3011If the message is frozen (attempts to deliver it are suspended) then the text
3012&"*** frozen ***"& is displayed at the end of this line.
3013
168e428f
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3014The recipients of the message (taken from the envelope, not the headers) are
3015displayed on subsequent lines. Those addresses to which the message has already
3016been delivered are marked with the letter D. If an original address gets
3017expanded into several addresses via an alias or forward file, the original is
3018displayed with a D only when deliveries for all of its child addresses are
3019complete.
3020
3021
9b371988
PH
3022.vitem &%-bpa%&
3023.oindex "&%-bpa%&"
3024This option operates like &%-bp%&, but in addition it shows delivered addresses
168e428f 3025that were generated from the original top level address(es) in each message by
9b371988
PH
3026alias or forwarding operations. These addresses are flagged with &"+D"& instead
3027of just &"D"&.
168e428f
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3028
3029
9b371988
PH
3030.vitem &%-bpc%&
3031.oindex "&%-bpc%&"
3032.cindex "queue" "count of messages on"
168e428f
PH
3033This option counts the number of messages on the queue, and writes the total
3034to the standard output. It is restricted to admin users, unless
9b371988 3035&%queue_list_requires_admin%& is set false.
168e428f
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3036
3037
9b371988
PH
3038.vitem &%-bpr%&
3039.oindex "&%-bpr%&"
3040This option operates like &%-bp%&, but the output is not sorted into
168e428f
PH
3041chronological order of message arrival. This can speed it up when there are
3042lots of messages on the queue, and is particularly useful if the output is
3043going to be post-processed in a way that doesn't need the sorting.
3044
9b371988
PH
3045.vitem &%-bpra%&
3046.oindex "&%-bpra%&"
3047This option is a combination of &%-bpr%& and &%-bpa%&.
168e428f 3048
9b371988
PH
3049.vitem &%-bpru%&
3050.oindex "&%-bpru%&"
3051This option is a combination of &%-bpr%& and &%-bpu%&.
168e428f
PH
3052
3053
9b371988
PH
3054.vitem &%-bpu%&
3055.oindex "&%-bpu%&"
3056This option operates like &%-bp%& but shows only undelivered top-level
3057addresses for each message displayed. Addresses generated by aliasing or
3058forwarding are not shown, unless the message was deferred after processing by a
3059router with the &%one_time%& option set.
168e428f
PH
3060
3061
9b371988
PH
3062.vitem &%-brt%&
3063.oindex "&%-brt%&"
3064.cindex "testing" "retry configuration"
3065.cindex "retry" "configuration testing"
168e428f
PH
3066This option is for testing retry rules, and it must be followed by up to three
3067arguments. It causes Exim to look for a retry rule that matches the values
3068and to write it to the standard output. For example:
9b371988
PH
3069.code
3070exim -brt bach.comp.mus.example
3071Retry rule: *.comp.mus.example F,2h,15m; F,4d,30m;
3072.endd
3073See chapter &<<CHAPretry>>& for a description of Exim's ret