4 This file contains descriptions of new features that have been added to Exim.
5 Before a formal release, there may be quite a lot of detail so that people can
6 test from the snapshots or the CVS before the documentation is updated. Once
7 the documentation is updated, this file is reduced to a short list.
12 1. New options for the ratelimit ACL condition: /count= and /unique=.
13 The /noupdate option has been replaced by a /readonly option.
19 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
20 or off in the resolver library.
26 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
27 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
28 libraries. The following global options have been added in support of
29 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
30 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
32 2. The pipe transport now takes a boolean option, "freeze_signal", default
33 false. When true, if the external delivery command exits on a signal then
34 Exim will freeze the message in the queue, instead of generating a bounce.
36 3. Log filenames may now use %M as an escape, instead of %D (still available).
37 The %M pattern expands to yyyymm, providing month-level resolution.
39 4. The $message_linecount variable is now updated for the maildir_tag option,
40 in the same way as $message_size, to reflect the real number of lines,
41 including any header additions or removals from transport.
43 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
44 Exim now selects entries randomly, to better scale in a cluster setup.
50 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
51 the flaw permitted the Exim run-time user to cause root to append to
52 arbitrary files of the attacker's choosing, with the content based
53 on content supplied by the attacker.
55 2. Exim now supports loading some lookup types at run-time, using your
56 platform's dlopen() functionality. This has limited platform support
57 and the intention is not to support every variant, it's limited to
58 dlopen(). This permits the main Exim binary to not be linked against
59 all the libraries needed for all the lookup types.
65 NOTE: this version is not guaranteed backwards-compatible, please read the
68 1. A new main configuration option, "openssl_options", is available if Exim
69 is built with SSL support provided by OpenSSL. The option allows
70 administrators to specify OpenSSL options to be used on connections;
71 typically this is to set bug compatibility features which the OpenSSL
72 developers have not enabled by default. There may be security
73 consequences for certain options, so these should not be changed
76 2. A new pipe transport option, "permit_coredumps", may help with problem
77 diagnosis in some scenarios. Note that Exim is typically installed as
78 a setuid binary, which on most OSes will inhibit coredumps by default,
79 so that safety mechanism would have to be overridden for this option to
80 be able to take effect.
82 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
83 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
84 Note that this switches Exim to use a new API ("INSTREAM") and a future
85 release of ClamAV will remove support for the old API ("STREAM").
87 The av_scanner option, when set to "clamd", now takes an optional third
88 part, "local", which causes Exim to pass a filename to ClamAV instead of
89 the file content. This is the same behaviour as when clamd is pointed at
90 a Unix-domain socket. For example:
92 av_scanner = clamd:192.0.2.3 1234:local
94 ClamAV's ExtendedDetectionInfo response format is now handled.
96 4. There is now a -bmalware option, restricted to admin users. This option
97 takes one parameter, a filename, and scans that file with Exim's
98 malware-scanning framework. This is intended purely as a debugging aid
99 to ensure that Exim's scanning is working, not to replace other tools.
100 Note that the ACL framework is not invoked, so if av_scanner references
101 ACL variables without a fallback then this will fail.
103 5. There is a new expansion operator, "reverse_ip", which will reverse IP
104 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
106 ${reverse_ip:192.0.2.4}
108 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
109 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
111 6. There is a new ACL control called "debug", to enable debug logging.
112 This allows selective logging of certain incoming transactions within
113 production environments, with some care. It takes two options, "tag"
114 and "opts"; "tag" is included in the filename of the log and "opts"
115 is used as per the -d<options> command-line option. Examples, which
116 don't all make sense in all contexts:
119 control = debug/tag=.$sender_host_address
120 control = debug/opts=+expand+acl
121 control = debug/tag=.$message_exim_id/opts=+expand
123 7. It has always been implicit in the design and the documentation that
124 "the Exim user" is not root. src/EDITME said that using root was
125 "very strongly discouraged". This is not enough to keep people from
126 shooting themselves in the foot in days when many don't configure Exim
127 themselves but via package build managers. The security consequences of
128 running various bits of network code are severe if there should be bugs in
129 them. As such, the Exim user may no longer be root. If configured
130 statically, Exim will refuse to build. If configured as ref:user then Exim
131 will exit shortly after start-up. If you must shoot yourself in the foot,
132 then henceforth you will have to maintain your own local patches to strip
135 8. There is a new expansion operator, bool_lax{}. Where bool{} uses the ACL
136 condition logic to determine truth/failure and will fail to expand many
137 strings, bool_lax{} uses the router condition logic, where most strings
139 Note: bool{00} is false, bool_lax{00} is true.
141 9. Routers now support multiple "condition" tests,
143 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
144 Setting this allows an admin to define which entry in the tcpwrappers
145 config file will be used to control access to the daemon. This option
146 is only available when Exim is built with USE_TCP_WRAPPERS. The
147 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
150 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
151 the Exim run-time user, instead of root.
153 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
154 is forced on. This is mitigated by the new build option
155 TRUSTED_CONFIG_LIST which defines a list of configuration files which
156 are trusted; one per line. If a config file is owned by root and matches
157 a pathname in the list, then it may be invoked by the Exim build-time
158 user without Exim relinquishing root privileges.
160 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
161 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
162 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
163 include the main config. As a transition mechanism, we are temporarily
164 providing a work-around: the new build option WHITELIST_D_MACROS provides
165 a colon-separated list of macro names which may be overridden by the Exim
166 run-time user. The values of these macros are constrained to the regex
167 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
173 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
174 writable, the other to locking of MBX folders (not mbox).
176 2. MySQL stored procedures are now supported.
178 3. The dkim_domain transport option is now a list, not a single string, and
179 messages will be signed for each element in the list (discarding
182 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
183 in the presence of multiple character strings within the RR. Prior to 4.70,
184 only the first string would be returned. The dnsdb lookup now, by default,
185 preserves the pre-4.70 semantics, but also now takes an extended output
186 separator specification. The separator can be followed by a semicolon, to
187 concatenate the individual text strings together with no join character,
188 or by a comma and a second separator character, in which case the text
189 strings within a TXT record are joined on that second character.
190 Administrators are reminded that DNS provides no ordering guarantees
191 between multiple records in an RRset. For example:
193 foo.example. IN TXT "a" "b" "c"
194 foo.example. IN TXT "d" "e" "f"
196 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
197 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
198 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
204 1. Native DKIM support without an external library.
205 (Note that if no action to prevent it is taken, a straight upgrade will
206 result in DKIM verification of all signed incoming emails. See spec
207 for details on conditionally disabling)
209 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
211 3. There is now a bool{} expansion condition which maps certain strings to
212 true/false condition values (most likely of use in conjunction with the
213 and{} expansion operator).
215 4. The $spam_score, $spam_bar and $spam_report variables are now available
218 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
219 options, provided that Exim is invoked by an admin_user.
221 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
222 which increases compatibility with older clients at the cost of decreased
223 security. Don't set this unless you need to support such clients.
225 7. There is a new expansion operator, ${randint:...} which will produce a
226 "random" number less than the supplied integer. This randomness is
227 not guaranteed to be cryptographically strong, but depending upon how
228 Exim was built may be better than the most naive schemes.
230 8. Exim now explicitly ensures that SHA256 is available when linked against
233 9. The transport_filter_timeout option now applies to SMTP transports too.
239 1. Preliminary DKIM support in Experimental.
245 1. The body_linecount and body_zerocount C variables are now exported in the
248 2. When a dnslists lookup succeeds, the key that was looked up is now placed
249 in $dnslist_matched. When the key is an IP address, it is not reversed in
250 this variable (though it is, of course, in the actual lookup). In simple
253 deny dnslists = spamhaus.example
255 the key is also available in another variable (in this case,
256 $sender_host_address). In more complicated cases, however, this is not
257 true. For example, using a data lookup might generate a dnslists lookup
260 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
262 If this condition succeeds, the value in $dnslist_matched might be
263 192.168.6.7 (for example).
265 3. Authenticators now have a client_condition option. When Exim is running as
266 a client, it skips an authenticator whose client_condition expansion yields
267 "0", "no", or "false". This can be used, for example, to skip plain text
268 authenticators when the connection is not encrypted by a setting such as:
270 client_condition = ${if !eq{$tls_cipher}{}}
272 Note that the 4.67 documentation states that $tls_cipher contains the
273 cipher used for incoming messages. In fact, during SMTP delivery, it
274 contains the cipher used for the delivery. The same is true for
277 4. There is now a -Mvc <message-id> option, which outputs a copy of the
278 message to the standard output, in RFC 2822 format. The option can be used
279 only by an admin user.
281 5. There is now a /noupdate option for the ratelimit ACL condition. It
282 computes the rate and checks the limit as normal, but it does not update
283 the saved data. This means that, in relevant ACLs, it is possible to lookup
284 the existence of a specified (or auto-generated) ratelimit key without
285 incrementing the ratelimit counter for that key.
287 In order for this to be useful, another ACL entry must set the rate
288 for the same key somewhere (otherwise it will always be zero).
293 # Read the rate; if it doesn't exist or is below the maximum
295 deny ratelimit = 100 / 5m / strict / noupdate
296 log_message = RATE: $sender_rate / $sender_rate_period \
297 (max $sender_rate_limit)
299 [... some other logic and tests...]
301 warn ratelimit = 100 / 5m / strict / per_cmd
302 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
303 (max $sender_rate_limit)
304 condition = ${if le{$sender_rate}{$sender_rate_limit}}
308 6. The variable $max_received_linelength contains the number of bytes in the
309 longest line that was received as part of the message, not counting the
310 line termination character(s).
312 7. Host lists can now include +ignore_defer and +include_defer, analagous to
313 +ignore_unknown and +include_unknown. These options should be used with
314 care, probably only in non-critical host lists such as whitelists.
316 8. There's a new option called queue_only_load_latch, which defaults true.
317 If set false when queue_only_load is greater than zero, Exim re-evaluates
318 the load for each incoming message in an SMTP session. Otherwise, once one
319 message is queued, the remainder are also.
321 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
322 cases when an SMTP session ends without sending QUIT. However, when Exim
323 itself is is bad trouble, such as being unable to write to its log files,
324 this ACL is not run, because it might try to do things (such as write to
325 log files) that make the situation even worse.
327 Like the QUIT ACL, this new ACL is provided to make it possible to gather
328 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
329 modifier is forbidden in this ACL.
331 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
332 to a string that indicates the reason for the termination of the SMTP
333 connection. The possible values are:
335 acl-drop Another ACL issued a "drop" command
336 bad-commands Too many unknown or non-mail commands
337 command-timeout Timeout while reading SMTP commands
338 connection-lost The SMTP connection has been lost
339 data-timeout Timeout while reading message data
340 local-scan-error The local_scan() function crashed
341 local-scan-timeout The local_scan() function timed out
342 signal-exit SIGTERM or SIGINT
343 synchronization-error SMTP synchronization error
344 tls-failed TLS failed to start
346 In most cases when an SMTP connection is closed without having received
347 QUIT, Exim sends an SMTP response message before actually closing the
348 connection. With the exception of acl-drop, the default message can be
349 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
350 "drop" verb in another ACL, it is the message from the other ACL that is
353 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
354 servers with individual queries. This is done by starting the query with
355 "servers=x:y:z;", where each item in the list may take one of two forms:
357 (1) If it is just a host name, the appropriate global option (mysql_servers
358 or pgsql_servers) is searched for a host of the same name, and the
359 remaining parameters (database, user, password) are taken from there.
361 (2) If it contains any slashes, it is taken as a complete parameter set.
363 The list of servers is used in exactly the same was as the global list.
364 Once a connection to a server has happened and a query has been
365 successfully executed, processing of the lookup ceases.
367 This feature is intended for use in master/slave situations where updates
368 are occurring, and one wants to update a master rather than a slave. If the
369 masters are in the list for reading, you might have:
371 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
373 In an updating lookup, you could then write
375 ${lookup mysql{servers=master; UPDATE ...}
377 If, on the other hand, the master is not to be used for reading lookups:
379 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
381 you can still update the master by
383 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
385 11. The message_body_newlines option (default FALSE, for backwards
386 compatibility) can be used to control whether newlines are present in
387 $message_body and $message_body_end. If it is FALSE, they are replaced by
394 1. There is a new log selector called smtp_no_mail, which is not included in
395 the default setting. When it is set, a line is written to the main log
396 whenever an accepted SMTP connection terminates without having issued a
399 2. When an item in a dnslists list is followed by = and & and a list of IP
400 addresses, the behaviour was not clear when the lookup returned more than
401 one IP address. This has been solved by the addition of == and =& for "all"
402 rather than the default "any" matching.
404 3. Up till now, the only control over which cipher suites GnuTLS uses has been
405 for the cipher algorithms. New options have been added to allow some of the
406 other parameters to be varied.
408 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
409 set, Exim compiles a runtime option called disable_fsync.
411 5. There is a new variable called $smtp_count_at_connection_start.
413 6. There's a new control called no_pipelining.
415 7. There are two new variables called $sending_ip_address and $sending_port.
416 These are set whenever an SMTP connection to another host has been set up.
418 8. The expansion of the helo_data option in the smtp transport now happens
419 after the connection to the server has been made.
421 9. There is a new expansion operator ${rfc2047d: that decodes strings that
422 are encoded as per RFC 2047.
424 10. There is a new log selector called "pid", which causes the current process
425 id to be added to every log line, in square brackets, immediately after the
428 11. Exim has been modified so that it flushes SMTP output before implementing
429 a delay in an ACL. It also flushes the output before performing a callout,
430 as this can take a substantial time. These behaviours can be disabled by
431 obeying control = no_delay_flush or control = no_callout_flush,
432 respectively, at some earlier stage of the connection.
434 12. There are two new expansion conditions that iterate over a list. They are
435 called forany and forall.
437 13. There's a new global option called dsn_from that can be used to vary the
438 contents of From: lines in bounces and other automatically generated
439 messages ("delivery status notifications" - hence the name of the option).
441 14. The smtp transport has a new option called hosts_avoid_pipelining.
443 15. By default, exigrep does case-insensitive matches. There is now a -I option
444 that makes it case-sensitive.
446 16. A number of new features ("addresses", "map", "filter", and "reduce") have
447 been added to string expansions to make it easier to process lists of
448 items, typically addresses.
450 17. There's a new ACL modifier called "continue". It does nothing of itself,
451 and processing of the ACL always continues with the next condition or
452 modifier. It is provided so that the side effects of expanding its argument
455 18. It is now possible to use newline and other control characters (those with
456 values less than 32, plus DEL) as separators in lists.
458 19. The exigrep utility now has a -v option, which inverts the matching
461 20. The host_find_failed option in the manualroute router can now be set to
468 No new features were added to 4.66.
474 No new features were added to 4.65.
480 1. ACL variables can now be given arbitrary names, as long as they start with
481 "acl_c" or "acl_m" (for connection variables and message variables), are at
482 least six characters long, with the sixth character being either a digit or
485 2. There is a new ACL modifier called log_reject_target. It makes it possible
486 to specify which logs are used for messages about ACL rejections.
488 3. There is a new authenticator called "dovecot". This is an interface to the
489 authentication facility of the Dovecot POP/IMAP server, which can support a
490 number of authentication methods.
492 4. The variable $message_headers_raw provides a concatenation of all the
493 messages's headers without any decoding. This is in contrast to
494 $message_headers, which does RFC2047 decoding on the header contents.
496 5. In a DNS black list, if two domain names, comma-separated, are given, the
497 second is used first to do an initial check, making use of any IP value
498 restrictions that are set. If there is a match, the first domain is used,
499 without any IP value restrictions, to get the TXT record.
501 6. All authenticators now have a server_condition option.
503 7. There is a new command-line option called -Mset. It is useful only in
504 conjunction with -be (that is, when testing string expansions). It must be
505 followed by a message id; Exim loads the given message from its spool
506 before doing the expansions.
508 8. Another similar new command-line option is called -bem. It operates like
509 -be except that it must be followed by the name of a file that contains a
512 9. When an address is delayed because of a 4xx response to a RCPT command, it
513 is now the combination of sender and recipient that is delayed in
514 subsequent queue runs until its retry time is reached.
516 10. Unary negation and the bitwise logical operators and, or, xor, not, and
517 shift, have been added to the eval: and eval10: expansion items.
519 11. The variables $interface_address and $interface_port have been renamed
520 as $received_ip_address and $received_port, to make it clear that they
521 relate to message reception rather than delivery. (The old names remain
522 available for compatibility.)
524 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
525 to vary the message that is sent when an SMTP command is accepted.
531 1. There is a new Boolean option called filter_prepend_home for the redirect
534 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
535 start of receiving a non-SMTP message, before any of the message has been
538 3. When an SMTP error message is specified in a "message" modifier in an ACL,
539 or in a :fail: or :defer: message in a redirect router, Exim now checks the
540 start of the message for an SMTP error code.
542 4. There is a new parameter for LDAP lookups called "referrals", which takes
543 one of the settings "follow" (the default) or "nofollow".
545 5. Version 20070721.2 of exipick now included, offering these new options:
547 After all other sorting options have bee processed, reverse order
548 before displaying messages (-R is synonym).
550 Randomize order of matching messages before displaying.
552 Instead of displaying the matching messages, display the sum
554 --sort <variable>[,<variable>...]
555 Before displaying matching messages, sort the messages according to
556 each messages value for each variable.
558 Negate the value for every test (returns inverse output from the
559 same criteria without --not).
565 1. The ${readsocket expansion item now supports Internet domain sockets as well
566 as Unix domain sockets. If the first argument begins "inet:", it must be of
567 the form "inet:host:port". The port is mandatory; it may be a number or the
568 name of a TCP port in /etc/services. The host may be a name, or it may be an
569 IP address. An ip address may optionally be enclosed in square brackets.
570 This is best for IPv6 addresses. For example:
572 ${readsocket{inet:[::1]:1234}{<request data>}...
574 Only a single host name may be given, but if looking it up yield more than
575 one IP address, they are each tried in turn until a connection is made. Once
576 a connection has been made, the behaviour is as for ${readsocket with a Unix
579 2. If a redirect router sets up file or pipe deliveries for more than one
580 incoming address, and the relevant transport has batch_max set greater than
581 one, a batch delivery now occurs.
583 3. The appendfile transport has a new option called maildirfolder_create_regex.
584 Its value is a regular expression. For a maildir delivery, this is matched
585 against the maildir directory; if it matches, Exim ensures that a
586 maildirfolder file is created alongside the new, cur, and tmp directories.
592 The documentation is up-to-date for the 4.61 release. Major new features since
593 the 4.60 release are:
595 . An option called disable_ipv6, to disable the use of IPv6 completely.
597 . An increase in the number of ACL variables to 20 of each type.
599 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
600 $2, $3, (though those are still set) because the numeric variables get used
601 for other things in complicated expansions.
603 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
605 . It is possible to use setclassresources() on some BSD OS to control the
606 resources used in pipe deliveries.
608 . A new ACL modifier called add_header, which can be used with any verb.
610 . More errors are detectable in retry rules.
612 There are a number of other additions too.
618 The documentation is up-to-date for the 4.60 release. Major new features since
619 the 4.50 release are:
621 . Support for SQLite.
623 . Support for IGNOREQUOTA in LMTP.
625 . Extensions to the "submission mode" features.
627 . Support for Client SMTP Authorization (CSA).
629 . Support for ratelimiting hosts and users.
631 . New expansion items to help with the BATV "prvs" scheme.
633 . A "match_ip" condition, that matches an IP address against a list.
635 There are many more minor changes.