Added Tony's defer_foo patch to dnsdb lookups.
[exim.git] / doc / doc-txt / NewStuff
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ff4dbb19 1$Cambridge: exim/doc/doc-txt/NewStuff,v 1.21 2004/12/20 15:24:27 ph10 Exp $
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2
3New Features in Exim
4--------------------
5
6This file contains descriptions of new features that have been added to Exim,
7but have not yet made it into the main manual (which is most conveniently
8updated when there is a relatively large batch of changes). The doc/ChangeLog
9file contains a listing of all changes, including bug fixes.
10
11
f7b63901 12Version 4.50
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13------------
14
15 1. There is a new build-time option called CONFIGURE_GROUP which works like
16 CONFIGURE_OWNER. It specifies one additional group that is permitted for
17 the runtime configuration file when the group write permission is set.
18
51a0ece1 19 2. The "control=submission" facility has a new option /sender_retain. This
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20 has the effect of setting local_sender_retain true and local_from_check
21 false for the incoming message in which it is encountered.
22
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23 3. $recipients is now available in the predata ACL (oversight).
24
25 4. The value of address_data from a sender verification is now available in
26 $sender_address_data in subsequent conditions in the ACL statement. Note:
27 this is just like $address_data. The value does not persist after the end
28 of the current ACL statement. If you want to preserve it, you can use one
29 of the ACL variables.
30
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31 5. The redirect router has two new options: forbid_sieve_filter and
32 forbid_exim_filter. When filtering is enabled by allow_filter, these
33 options control which type(s) of filtering are permitted. By default, both
34 Exim and Sieve filters are allowed.
35
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36 6. A new option for callouts makes it possible to set a different (usually
37 smaller) timeout for making the SMTP connection. The keyword is "connect".
38 For example:
39
40 verify = sender/callout=5s,connect=1s
41
42 If not specified, it defaults to the general timeout value.
43
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44 7. The new variables $sender_verify_failure and $recipient_verify_failure
45 contain information about exactly what failed. In an ACL, after one of
46 these failures, the relevant variable contains one of the following words:
47
48 qualify the address was unqualified (no domain), and the message
49 was neither local nor came from an exempted host;
50
51 route routing failed;
52
53 mail routing succeeded, and a callout was attempted; rejection
54 occurred at or before the MAIL command (that is, on initial
55 connection, HELO, or MAIL);
56
57 recipient the RCPT command in a callout was rejected;
58
59 postmaster the postmaster check in a callout was rejected.
60
61 The main use of these variables is expected to be to distinguish between
62 rejections of MAIL and rejections of RCPT.
63
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64 8. The command line option -dd behaves exactly like -d except when used on a
65 command that starts a daemon process. In that case, debugging is turned off
66 for the subprocesses that the daemon creates. Thus, it is useful for
67 monitoring the behaviour of the daemon without creating as much output as
68 full debugging.
69
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70 9. $host_address is now set to the target address during the checking of
71 ignore_target_hosts.
72
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7310. There are four new variables called $spool_space, $log_space,
74 $spool_inodes, and $log_inodes. The first two contain the amount of free
75 space in the disk partitions where Exim has its spool directory and log
76 directory, respectively. (When these are in the same partition, the values
77 will, of course, be the same.) The second two variables contain the numbers
78 of free inodes in the respective partitions.
79
80 NOTE: Because disks can nowadays be very large, the values in the space
81 variables are in kilobytes rather than in bytes. Thus, for example, to
82 check in an ACL that there is at least 50M free on the spool, you would
83 write:
84
85 condition = ${if > {$spool_space}{50000}{yes}{no}}
86
87 The values are recalculated whenever any of these variables is referenced.
88 If the relevant file system does not have the concept of inodes, the value
89 of those variables is -1. If the operating system does not have the ability
90 to find the amount of free space (only true for experimental systems), the
91 space value is -1.
2c7db3f5 92
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9311. It is now permitted to omit both strings after an "if" condition; if the
94 condition is true, the result is the string "true". As before, when the
95 second string is omitted, a false condition yields an empty string. This
96 makes it less cumbersome to write custom ACL and router conditions. For
97 example, instead of
98
99 condition = ${if eq {$acl_m4}{1}{yes}{no}}
100
101 or the shorter form
102
103 condition = ${if eq {$acl_m4}{1}{yes}}
104
105 (because the second string has always defaulted to ""), you can now write
106
107 condition = ${if eq {$acl_m4}{1}}
108
109 Previously this was a syntax error.
110
ea3bc19b 11112. There is a new "record type" that can be specified in dnsdb lookups. It
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112 is "zns" (for "zone NS"). It performs a lookup for NS records on the given
113 domain, but if none are found, it removes the first component of the domain
114 name, and tries again. This process continues until NS records are found
115 or there are no more components left (or there's a DNS error). In other
116 words, it may return the name servers for a top-level domain, but it never
117 returns the root name servers. If there are no NS records for the top-level
118 domain, the lookup fails.
119
120 For example, ${lookup dnsdb{zns=xxx.quercite.com}} returns the name
121 servers for quercite.com, whereas ${lookup dnsdb{zns=xxx.edu}} returns
122 the name servers for edu, assuming in each case that there are no NS
123 records for the full domain name.
124
125 You should be careful about how you use this lookup because, unless the
126 top-level domain does not exist, the lookup will always return some host
127 names. The sort of use to which this might be put is for seeing if the name
128 servers for a given domain are on a blacklist. You can probably assume that
129 the name servers for the high-level domains such as .com or .co.uk are not
130 going to be on such a list.
131
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13213. Another new "record type" is "mxh"; this looks up MX records just as "mx"
133 does, but it returns only the names of the hosts, omitting the priority
134 values.
135
13614. It is now possible to specify a list of domains or IP addresses to be
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137 looked up in a dnsdb lookup. The list is specified in the normal Exim way,
138 with colon as the default separator, but with the ability to change this.
139 For example:
140
141 ${lookup dnsdb{one.domain.com:two.domain.com}}
142 ${lookup dnsdb{a=one.host.com:two.host.com}}
143 ${lookup dnsdb{ptr = <; 1.2.3.4 ; 4.5.6.8}}
144
145 In order to retain backwards compatibility, there is one special case: if
146 the lookup type is PTR and no change of separator is specified, Exim looks
147 to see if the rest of the string is precisely one IPv6 address. In this
148 case, it does not treat it as a list.
149
150 The data from each lookup is concatenated, with newline separators (by
151 default - see 14 below), in the same way that multiple DNS records for a
152 single item are handled.
153
c38d6da9 154 The dnsdb lookup fails only if all the DNS lookups fail. If there is a
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155 temporary DNS error for any of them, the behaviour is controlled by
156 an optional keyword followed by a comma that may appear before the record
157 type. The possible keywords are "defer_strict", "defer_never", and
158 "defer_lax". With "strict" behaviour, any temporary DNS error causes the
159 whole lookup to defer. With "never" behaviour, a temporary DNS error is
160 ignored, and the behaviour is as if the DNS lookup failed to find anything.
161 With "lax" behaviour, all the queries are attempted, but a temporary DNS
162 error causes the whole lookup to defer only if none of the other lookups
163 succeed. The default is "lax", so the following lookups are equivalent:
164
165 ${lookup dnsdb{defer_lax,a=one.host.com:two.host.com}}
166 ${lookup dnsdb{a=one.host.com:two.host.com}}
167
168 Thus, in the default case, as long as at least one of the DNS lookups
169 yields some data, the dnsdb lookup succeeds.
7bb56e1f 170
ea3bc19b 17115. It is now possible to specify the character to be used as a separator when
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172 a dnsdb lookup returns data from more than one DNS record. The default is a
173 newline. To specify a different character, put '>' followed by the new
174 character at the start of the query. For example:
175
176 ${lookup dnsdb{>: a=h1.test.ex:h2.test.ex}}
ea3bc19b 177 ${lookup dnsdb{>| mxh=<;m1.test.ex;m2.test.ex}}
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178
179 It is permitted to specify a space as the separator character. Note that
180 more than one DNS record can be found for a single lookup item; this
181 feature is relevant even when you do not specify a list.
182
183 The same effect could be achieved by wrapping the lookup in ${tr...}; this
184 feature is just a syntactic simplification.
185
ea3bc19b 18616. It is now possible to supply a list of domains and/or IP addresses to be
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187 lookup up in a DNS blacklist. Previously, only a single domain name could
188 be given, for example:
189
190 dnslists = black.list.tld/$sender_host_name
191
192 What follows the slash can now be a list. As with all lists, the default
193 separator is a colon. However, because this is a sublist within the list of
194 DNS blacklist domains, it is necessary either to double the separators like
195 this:
196
197 dnslists = black.list.tld/name.1::name.2
198
199 or to change the separator character, like this:
200
201 dnslists = black.list.tld/<;name.1;name.2
202
203 If an item in the list is an IP address, it is inverted before the DNS
204 blacklist domain is appended. If it is not an IP address, no inversion
205 occurs. Consider this condition:
206
207 dnslists = black.list.tls/<;192.168.1.2;a.domain
208
209 The DNS lookups that occur are for
210
211 2.1.168.192.black.list.tld and a.domain.black.list.tld
212
213 Once a DNS record has been found (that matches a specific IP return
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214 address, if specified), no further lookups are done. If there is a
215 temporary DNS error, the rest of the sublist of domains or IP addresses is
216 tried. The dnslists item itself defers only if none of the other DNS
217 lookups in this sublist succeeds. In other words, a successful lookup for
218 any of the items in the sublist overrides a defer for a previous item.
0bcb2a0e 219
ea3bc19b 22017. The log selector queue_time_overall causes Exim to output the time spent on
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221 the queue as an addition to the "Completed" message. Like queue_time (which
222 puts the queue time on individual delivery lines), the time is tagged with
223 "QT=", and it is measured from the time that the message starts to be
224 received, so it includes the reception time.
225
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22618. It is now possible to use both -bF and -bf on the same command, in order to
227 test a system filter and a user filter in the same run. For example:
228
229 exim -bF /system/filter -bf /user/filter </test/message
230
231 This is helpful when the system filter adds header lines or sets filter
232 variables that are used by the user filter.
233
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23419. The Exiscan patch is now merged into the main source. See src/EDITME for
235 parameters for the build.
236
35edf2ff 237
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238Version 4.43
239------------
240
241 1. There is a new Boolean global option called mua_wrapper, defaulting false.
242 This causes Exim to run an a restricted mode, in order to provide a very
243 specific service.
244
245 Background: On a personal computer, it is a common requirement for all
246 email to be sent to a smarthost. There are plenty of MUAs that can be
247 configured to operate that way, for all the popular operating systems.
248 However, there are MUAs for Unix-like systems that cannot be so configured:
249 they submit messages using the command line interface of
250 /usr/sbin/sendmail. In addition, utility programs such as cron submit
251 messages this way.
252
253 Requirement: The requirement is for something that can provide the
254 /usr/sbin/sendmail interface and deliver messages to a smarthost, but not
255 provide any queueing or retrying facilities. Furthermore, the delivery to
256 the smarthost should be synchronous, so that if it fails, the sending MUA
257 is immediately informed. In other words, we want something that in effect
258 converts a command-line MUA into a TCP/SMTP MUA.
259
260 Solutions: There are a number of applications (for example, ssmtp) that do
261 this job. However, people have found them to be lacking in various ways.
262 For instance, some sites want to allow aliasing and forwarding before
263 sending to the smarthost.
264
265 Using Exim: Exim already had the necessary infrastructure for doing this
266 job. Just a few tweaks were needed to make it behave as required, though it
267 is somewhat of an overkill to use a fully-featured MTA for this purpose.
268
269 Setting mua_wrapper=true causes Exim to run in a special mode where it
270 assumes that it is being used to "wrap" a command-line MUA in the manner
271 just described.
272
273 If you set mua_wrapper=true, you also need to provide a compatible router
274 and transport configuration. Typically there will be just one router and
275 one transport, sending everything to a smarthost.
276
277 When run in MUA wrapping mode, the behaviour of Exim changes in the
278 following ways:
279
280 (a) A daemon cannot be run, nor will Exim accept incoming messages from
281 inetd. In other words, the only way to submit messages is via the
282 command line.
283
284 (b) Each message is synchonously delivered as soon as it is received (-odi
285 is assumed). All queueing options (queue_only, queue_smtp_domains,
286 control=queue, control=freeze in an ACL etc.) are quietly ignored. The
287 Exim reception process does not finish until the delivery attempt is
288 complete. If the delivery was successful, a zero return code is given.
289
290 (c) Address redirection is permitted, but the final routing for all
291 addresses must be to the same remote transport, and to the same list of
292 hosts. Furthermore, the return_address must be the same for all
293 recipients, as must any added or deleted header lines. In other words,
294 it must be possible to deliver the message in a single SMTP
295 transaction, however many recipients there are.
296
297 (d) If the conditions in (c) are not met, or if routing any address results
298 in a failure or defer status, or if Exim is unable to deliver all the
299 recipients successfully to one of the hosts immediately, delivery of
300 the entire message fails.
301
302 (e) Because no queueing is allowed, all failures are treated as permanent;
303 there is no distinction between 4xx and 5xx SMTP response codes from
304 the smarthost. Furthermore, because only a single yes/no response can
305 be given to the caller, it is not possible to deliver to some
306 recipients and not others. If there is an error (temporary or
307 permanent) for any recipient, all are failed.
308
309 (f) If more than one host is listed, Exim will try another host after a
310 connection failure or a timeout, in the normal way. However, if this
311 kind of failure happens for all the hosts, the delivery fails.
312
313 (g) When delivery fails, an error message is written to the standard error
314 stream (as well as to Exim's log), and Exim exits to the caller with a
315 return code value 1. The message is expunged from Exim's spool files.
316 No bounce messages are ever generated.
317
318 (h) No retry data is maintained, and any retry rules are ignored.
319
320 (i) A number of Exim options are overridden: deliver_drop_privilege is
321 forced true, max_rcpt in the smtp transport is forced to "unlimited",
322 remote_max_parallel is forced to one, and fallback hosts are ignored.
323
324 The overall effect is that Exim makes a single synchronous attempt to
325 deliver the message, failing if there is any kind of problem. Because no
326 local deliveries are done and no daemon can be run, Exim does not need root
327 privilege. It should be possible to run it setuid=exim instead of
328 setuid=root. See section 48.3 in the 4.40 manual for a general discussion
329 about the advantages and disadvantages of running without root privilege.
330
331 2. There have been problems with DNS servers when SRV records are looked up.
332 Some mis-behaving servers return a DNS error or timeout when a non-existent
333 SRV record is sought. Similar problems have in the past been reported for
334 MX records. The global dns_again_means_nonexist option can help with this
335 problem, but it is heavy-handed because it is a global option. There are
336 now two new options for the dnslookup router. They are called
337 srv_fail_domains and mx_fail_domains. In each case, the value is a domain
338 list. If an attempt to look up an SRV or MX record results in a DNS failure
339 or "try again" response, and the domain matches the relevant list, Exim
340 behaves as if the DNS had responded "no such record". In the case of an SRV
341 lookup, this means that the router proceeds to look for MX records; in the
342 case of an MX lookup, it proceeds to look for A or AAAA records, unless the
343 domain matches mx_domains.
344
345 3. The following functions are now available in the local_scan() API:
346
347 (a) void header_remove(int occurrence, uschar *name)
348
349 This function removes header lines. If "occurrence" is zero or negative,
350 all occurrences of the header are removed. If occurrence is greater
351 than zero, that particular instance of the header is removed. If no
352 header(s) can be found that match the specification, the function does
353 nothing.
354
355 (b) BOOL header_testname(header_line *hdr, uschar *name, int length,
356 BOOL notdel)
357
358 This function tests whether the given header has the given name. It
359 is not just a string comparison, because whitespace is permitted
360 between the name and the colon. If the "notdel" argument is TRUE, a
361 FALSE return is forced for all "deleted" headers; otherwise they are
362 not treated specially. For example:
363
364 if (header_testname(h, US"X-Spam", 6, TRUE)) ...
365
366 (c) void header_add_at_position(BOOL after, uschar *name, BOOL topnot,
367 int type, char *format, ...)
368
369 This function adds a new header line at a specified point in the header
370 chain. If "name" is NULL, the new header is added at the end of the
371 chain if "after" is TRUE, or at the start if "after" is FALSE. If
372 "name" is not NULL, the headers are searched for the first non-deleted
373 header that matches the name. If one is found, the new header is added
374 before it if "after" is FALSE. If "after" is true, the new header is
375 added after the found header and any adjacent subsequent ones with the
376 same name (even if marked "deleted"). If no matching non-deleted header
377 is found, the "topnot" option controls where the header is added. If it
378 is TRUE, addition is at the top; otherwise at the bottom. Thus, to add
379 a header after all the Received: headers, or at the top if there are no
380 Received: headers, you could use
381
382 header_add_at_position(TRUE, US"Received", TRUE, ' ', "X-xxx: ...");
383
384 Normally, there is always at least one non-deleted Received: header,
385 but there may not be if received_header_text expands to an empty
386 string.
387
388 (d) BOOL receive_remove_recipient(uschar *recipient)
389
390 This is a convenience function to remove a named recipient from the
391 list of recipients. It returns TRUE if a recipient was removed, and
392 FALSE if no matching recipient could be found. The argument must be a
393 complete email address.
394
395 4. When an ACL "warn" statement adds one or more header lines to a message,
396 they are added at the end of the existing header lines by default. It is
397 now possible to specify that any particular header line should be added
398 right at the start (before all the Received: lines) or immediately after
399 the first block of Received: lines in the message. This is done by
400 specifying :at_start: or :after_received: (or, for completeness, :at_end:)
401 before the text of the header line. (Header text cannot start with a colon,
402 as there has to be a header name first.) For example:
403
404 warn message = :after_received:X-My-Header: something or other...
405
406 If more than one header is supplied in a single warn statement, each one is
407 treated independently and can therefore be placed differently. If you add
408 more than one line at the start, or after the Received: block, they will
409 end up in reverse order.
410
411 Warning: This facility currently applies only to header lines that are
412 added in an ACL. It does NOT work for header lines that are added in a
413 system filter or in a router or transport.
414
415 5. There is now a new error code that can be used in retry rules. Its name is
416 "rcpt_4xx", and there are three forms. A literal "rcpt_4xx" matches any 4xx
417 error received for an outgoing SMTP RCPT command; alternatively, either the
418 first or both of the x's can be given as digits, for example: "rcpt_45x" or
419 "rcpt_436". If you want (say) to recognize 452 errors given to RCPT
420 commands by a particular host, and have only a one-hour retry for them, you
421 can set up a retry rule of this form:
422
423 the.host.name rcpt_452 F,1h,10m
424
425 Naturally, this rule must come before any others that would match.
426
427 These new errors apply to both outgoing SMTP (the smtp transport) and
428 outgoing LMTP (either the lmtp transport, or the smtp transport in LMTP
429 mode). Note, however, that they apply only to responses to RCPT commands.
430
431 6. The "postmaster" option of the callout feature of address verification has
432 been extended to make it possible to use a non-empty MAIL FROM address when
433 checking a postmaster address. The new suboption is called "postmaster_
434 mailfrom", and you use it like this:
435
436 require verify = sender/callout=postmaster_mailfrom=abc@x.y.z
437
438 Providing this suboption causes the postmaster check to be done using the
439 given address. The original "postmaster" option is equivalent to
440
441 require verify = sender/callout=postmaster_mailfrom=
442
443 If both suboptions are present, the rightmost one overrides.
444
445 Important notes:
446
447 (1) If you use a non-empty sender address for postmaster checking, there is
448 the likelihood that the remote host will itself initiate a callout
449 check back to your host to check that address. As this is a "normal"
450 callout check, the sender will most probably be empty, thus avoiding
451 possible callout loops. However, to be on the safe side it would be
452 best to set up your own ACLs so that they do not do sender verification
453 checks when the recipient is the address you use for postmaster callout
454 checking.
455
456 (2) The caching arrangements for postmaster checking do NOT take account of
457 the sender address. It is assumed that either the empty address, or a
458 fixed non-empty address will be used. All that Exim remembers is that
459 the postmaster check for the domain succeeded or failed.
460
461 7. When verifying addresses in header lines using the verify=header_sender
462 option, Exim behaves by default as if the addresses are envelope sender
463 addresses from a message. Callout verification therefore tests to see
464 whether a bounce message could be delivered, by using an empty address in
465 the MAIL FROM command. However, it is arguable that these addresses might
466 never be used as envelope senders, and could therefore justifiably reject
467 bounce messages (empty senders). There is now an additional callout option
468 for verify=header_sender that allows you to specify what address to use in
469 the MAIL FROM command. You use it as in this example:
470
471 require verify = header_sender/callout=mailfrom=abcd@x.y.z
472
473 Important notes:
474
475 (1) As in the case of postmaster_mailfrom (see above), you should think
476 about possible loops.
477
478 (2) In this case, as in the case of recipient callouts with non-empty
479 senders (the use_sender option), caching is done on the basis of a
480 recipient/sender pair.
481
482 8. If you build Exim with USE_READLINE=yes in Local/Makefile, it will try to
483 load libreadline dynamically whenever the -be (test expansion) option is
484 used without command line arguments. If successful, it will then use
485 readline() for reading the test data. A line history is supported. By the
486 time Exim does this, it is running as the calling user, so this should not
487 cause any security problems. Security is the reason why this is NOT
488 supported for -bt or -bv, when Exim is running as root or exim,
489 respectively. Note that this option adds to the size of the Exim binary,
490 because the dynamic loading library is not otherwise included. On my
491 desktop it adds about 2.5K. You may need to add -ldl to EXTRA_LIBS when you
492 set USE_READLINE=yes.
493
494 9. Added ${str2b64:<string>} to the expansion operators. This operator
495 converts an arbitrary string into one that is base64 encoded.
496
49710. A new authenticator, called cyrus_sasl, has been added. This requires
498 the presence of the Cyrus SASL library; it authenticates by calling this
499 library, which supports a number of authentication mechanisms, including
500 PLAIN and LOGIN, but also several others that Exim does not support
501 directly. The code for this authenticator was provided by Matthew
502 Byng-Maddick of A L Digital Ltd (http://www.aldigital.co.uk). Here follows
503 draft documentation:
504
505 xx. THE CYRUS_SASL AUTHENTICATOR
506
507 The cyrus_sasl authenticator provides server support for the Cyrus library
508 Implementation of the RFC 2222 "Simple Authentication and Security Layer".
509 It provides a gatewaying mechanism directly to the Cyrus interface, so if
510 your Cyrus library can do, for example, CRAM-MD5, then so can the
511 cyrus_sasl authenticator. By default it uses the public name of the driver
512 to determine which mechanism to support.
513
514 Where access to some kind of secret file is required, for example in GSSAPI
515 or CRAM-MD5, it is worth noting that the authenticator runs as the exim
516 user, and that the Cyrus SASL library has no way of escalating privileges
517 by default. You may also find you need to set environment variables,
518 depending on the driver you are using.
519
520 xx.1 Using cyrus_sasl as a server
521
522 The cyrus_sasl authenticator has four private options. It puts the username
523 (on a successful authentication) into $1.
524
525 server_hostname Type: string* Default: $primary_hostname
526
527 This option selects the hostname that is used when communicating with
528 the library. It is up to the underlying SASL plug-in what it does with
529 this data.
530
531 server_mech Type: string Default: public_name
532
533 This option selects the authentication mechanism this driver should
534 use. It allows you to use a different underlying mechanism from the
535 advertised name. For example:
536
537 sasl:
538 driver = cyrus_sasl
539 public_name = X-ANYTHING
540 server_mech = CRAM-MD5
541 server_set_id = $1
542
543 server_realm Type: string Default: unset
544
545 This is the SASL realm that the server is claiming to be in.
546
547 server_service Type: string Default: "smtp"
548
549 This is the SASL service that the server claims to implement.
550
551 For straigthforward cases, you do not need to set any of the
552 authenticator's private options. All you need to do is to specify an
553 appropriate mechanism as the public name. Thus, if you have a SASL library
554 that supports CRAM-MD5 and PLAIN, you might have two authenticators as
555 follows:
556
557 sasl_cram_md5:
558 driver = cyrus_sasl
559 public_name = CRAM-MD5
560 server_set_id = $1
561
562 sasl_plain:
563 driver = cyrus_sasl
564 public_name = PLAIN
565 server_set_id = $1
566
56711. There is a new global option called tls_on_connect_ports. Its value must be
568 a list of port numbers; the most common use is expected to be
569
570 tls_on_connect_ports = 465
571
572 Setting this option has the same effect as -tls-on-connect on the command
573 line, but only for the specified ports. It applies to all connections, both
574 via the daemon and via inetd. You still need to specify all the ports for
575 the daemon (using daemon_smtp_ports or local_interfaces or the -X command
576 line option) because this option does not add an extra port -- rather, it
577 specifies different behaviour on a port that is defined elsewhere. The
578 -tls-on-connect command line option overrides tls_on_connect_ports, and
579 forces tls-on-connect for all ports.
580
58112. There is a new ACL that is run when a DATA command is received, before the
582 data itself is received. The ACL is defined by acl_smtp_predata. (Compare
583 acl_smtp_data, which is run after the data has been received.)
584 This new ACL allows a negative response to be given to the DATA command
585 itself. Header lines added by MAIL or RCPT ACLs are not visible at this
586 time, but any that are defined here are visible when the acl_smtp_data ACL
587 is run.
588
58913. The "control=submission" ACL modifier has an option "/domain=xxx" which
590 specifies the domain to be used when creating From: or Sender: lines using
591 the authenticated id as a local part. If the option is supplied with an
592 empty domain, that is, just "/domain=", Exim assumes that the authenticated
593 id is a complete email address, and it uses it as is when creating From:
594 or Sender: lines.
595
59614. It is now possible to make retry rules that apply only when the failing
597 message has a specific sender. In particular, this can be used to define
598 retry rules that apply only to bounce messages. The syntax is to add a new
599 third item to a retry rule, of the form "senders=<address list>". The retry
600 timings themselves then become the fourth item. For example:
601
602 * * senders=: F,1h,30m
603
604 would match all bounce messages. If the address list contains white space,
605 it must be enclosed in quotes. For example:
606
607 a.domain timeout senders="x@b.dom : y@c.dom" G,8h,10m,1.5
608
609 When testing retry rules using -brt, you can supply a sender using the -f
610 command line option, like this:
611
612 exim -f "" -brt user@dom.ain
613
614 If you do not set -f with -brt, a retry rule that contains a senders list
615 will never be matched.
616
61715. Two new control modifiers have been added to ACLs: "control = enforce_sync"
618 and "control = no_enforce_sync". This makes it possible to be selective
619 about when SMTP synchronization is enforced. The global option
620 smtp_enforce_sync now specifies the default state of the switch. These
621 controls can appear in any ACL, but the most obvious place to put them is
622 in the ACL defined by acl_smtp_connect, which is run at the start of an
623 incoming SMTP connection, before the first synchronization check.
624
62516. Another two new control modifiers are "control = caseful_local_part" and
626 "control = caselower_local_part". These are permitted only in the ACL
627 specified by acl_smtp_rcpt (i.e. during RCPT processing). By default, the
628 contents of $local_part are lower cased before ACL processing.
629 After "control = caseful_local_part", any uppercase letters in the original
630 local part are restored in $local_part for the rest of the ACL, or until
631 "control = caselower_local_part" is encountered. However, this applies only
632 to local part handling that takes place directly in the ACL (for example,
633 as a key in lookups). If a "verify = recipient" test is obeyed, the
634 case-related handling of the local part during the verification is
635 controlled by the router configuration (see the caseful_local_part generic
636 router option).
637
638 This facility could be used, for example, to add a spam score to local
639 parts containing upper case letters. For example, using $acl_m4 to
640 accumulate the spam score:
641
642 warn control = caseful_local_part
643 set acl_m4 = ${eval:\
644 $acl_m4 + \
645 ${if match{$local_part}{[A-Z]}{1}{0}}\
646 }
647 control = caselower_local_part
648
649 Notice that we put back the lower cased version afterwards, assuming that
650 is what is wanted for subsequent tests.
651
65217. The option hosts_connection_nolog is provided so that certain hosts can be
653 excepted from logging when the +smtp_connection log selector is set. For
654 example, you might want not to log SMTP connections from local processes,
655 or from 127.0.0.1, or from your local LAN. The option is a host list with
656 an unset default. Because it is consulted in the main loop of the daemon,
657 you should strive to restrict its value to a short inline list of IP
658 addresses and networks. To disable logging SMTP connections from local
659 processes, you must create a host list with an empty item. For example:
660
661 hosts_connection_nolog = :
662
663 If the +smtp_connection log selector is not set, this option has no effect.
664
66518. There is now an acl called acl_smtp_quit, which is run for the QUIT
666 command. The outcome of the ACL does not affect the response code to QUIT,
667 which is always 221. Thus, the ACL does not in fact control any access.
668 For this reason, the only verbs that are permitted are "accept" and "warn".
669
670 The ACL can be used for tasks such as custom logging at the end of an SMTP
671 session. For example, you can use ACL variables in other ACLs to count
672 messages, recipients, etc., and log the totals at QUIT time using one or
673 more "logwrite" modifiers on a "warn" command.
674
675 You do not need to have a final "accept", but if you do, you can use a
676 "message" modifier to specify custom text that is sent as part of the 221
677 response.
678
679 This ACL is run only for a "normal" QUIT. For certain kinds of disastrous
680 failure (for example, failure to open a log file, or when Exim is bombing
681 out because it has detected an unrecoverable error), all SMTP commands
682 from the client are given temporary error responses until QUIT is received
683 or the connection is closed. In these special cases, the ACL is not run.
684
68519. The appendfile transport has two new options, mailbox_size and mailbox_
686 filecount. If either these options are set, it is expanded, and the result
687 is taken as the current size of the mailbox or the number of files in the
688 mailbox, respectively. This makes it possible to use some external means of
689 maintaining the data about the size of a mailbox for enforcing quota
690 limits. The result of expanding these option values must be a decimal
691 number, optionally followed by "K" or "M".
692
69320. It seems that there are broken clients in use that cannot handle multiline
694 SMTP responses. Can't people who implement these braindead programs read?
695 RFC 821 mentions multiline responses, and it is over 20 years old. They
696 must handle multiline responses for EHLO, or do they still use HELO?
697 Anyway, here is YAWFAB (yet another workaround for asinine brokenness).
698 There's a new ACL switch that can be set by
699
700 control = no_multiline_responses
701
702 If this is set, it suppresses multiline SMTP responses from ACL rejections.
703 One way of doing this would have been just to put out these responses as
704 one long line. However, RFC 2821 specifies a maximum of 512 bytes per
705 response ("use multiline responses for more" it says), and some of the
706 responses might get close to that. So I have implemented this by doing two
707 very easy things:
708
709 (1) Extra information that is normally output as part of a rejection
710 caused by sender verification failure is omitted. Only the final line
711 (typically "sender verification failed") is now sent.
712
713 (2) If a "message" modifier supplies a multiline response, only the first
714 line is output.
715
716 The setting of the switch can, of course, be made conditional on the
717 calling host.
718
71921. There is now support for the libradius library that comes with FreeBSD.
720 This is an alternative to the radiusclient library that Exim already
721 supports. To use the FreeBSD library, you need to set
722
723 RADIUS_LIB_TYPE=RADLIB
724
725 in Local/Makefile, in addition to RADIUS_CONFIGURE_FILE, and you probably
726 also need -libradius in EXTRALIBS.
727
728
729Version 4.42
730------------
731
732 1. The "personal" filter test is brought up-to-date with recommendations from
733 the Sieve specification: (a) The list of non-personal From: addresses now
734 includes "listserv", "majordomo", and "*-request"; (b) If the message
735 contains any header line starting with "List=-" it is treated as
736 non-personal.
737
738 2. The Sieve functionality has been extended to support the "copy" and
739 "vacation" extensions, and comparison tests.
740
741 3. There is now an overall timeout for performing a callout verification. It
742 defaults to 4 times the callout timeout, which applies to individual SMTP
743 commands during the callout. The overall timeout applies when there is more
744 than one host that can be tried. The timeout is checked before trying the
745 next host. This prevents very long delays if there are a large number of
746 hosts and all are timing out (e.g. when the network connections are timing
747 out). The value of the overall timeout can be changed by specifying an
748 additional sub-option for "callout", called "maxwait". For example:
749
750 verify = sender/callout=5s,maxwait=20s
751
752 4. Changes to the "personal" filter test:
753
754 (1) The list of non-personal local parts in From: addresses has been
755 extended to include "listserv", "majordomo", "*-request", and "owner-*",
756 taken from the Sieve specification recommendations.
757
758 (2) If the message contains any header line starting with "List-" it is
759 treated as non-personal.
760
761 (3) The test for "circular" in the Subject: header line has been removed
762 because it now seems ill-conceived.
763
764 5. The autoreply transport has a new option called never_mail. This is an
765 address list. If any run of the transport creates a message with a
766 recipient that matches any item in the list, that recipient is quietly
767 discarded. If all recipients are discarded, no message is created.
768
769
770Version 4.40
771------------
772
773The documentation is up-to-date for the 4.40 release. What follows here is a
774brief list of the new features that have been added since 4.30.
775
776 1. log_incoming_interface affects more log lines.
777
778 2. New ACL modifier "control = submission".
779
780 3. CONFIGURE_OWNER can be set at build time to define an alternative owner for
781 the configuration file, in addition to root and exim.
782
783 4. Added expansion variables $body_zerocount, $recipient_data, and
784 $sender_data.
785
786 5. The time of last modification of the "new" subdirectory is now used as the
787 "mailbox time last read" when there is a quota error for a maildir
788 delivery.
789
790 6. The special item "+ignore_unknown" may now appear in host lists.
791
792 7. The special domain-matching patterns @mx_any, @mx_primary, and
793 @mx_secondary can now be followed by "/ignore=<ip list>".
794
795 8. New expansion conditions: match_domain, match_address, match_local_part,
796 lt, lti, le, lei, gt, gti, ge, and new expansion operators time_interval,
797 eval10, and base62d.
798
799 9. New lookup type called "iplsearch".
800
80110. New log selectors ident_timeout, tls_certificate_verified, queue_time,
802 deliver_time, outgoing_port, return_path_on_delivery.
803
80411. New global options smtp_active_hostname and tls_require_ciphers.
805
80612. Exinext has -C and -D options.
807
80813. "domainlist_cache" forces caching of an apparently variable list.
809
81014. For compatibility with Sendmail, the command line option -prval:sval
811 is equivalent to -oMr rval -oMs sval.
812
81315. New callout options use_sender and use_postmaster for use when verifying
814 recipients.
815
81616. John Jetmore's "exipick" utility has been added to the distribution.
817
81817. The TLS code now supports CRLs.
819
82018. The dnslookup router and the dnsdb lookup type now support the use of SRV
821 records.
822
82319. The redirect router has a new option called qualify_domain.
824
82520. exigrep's output now also includes lines that are not related to any
826 particular message, but which do match the pattern.
827
82821. New global option write_rejectlog. If it is set false, Exim no longer
829 writes anything to the reject log.
830
831****