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 authenticator driver, "gsasl". Server-only (at present).
13 This is a SASL interface, licensed under GPL, which can be found at
14 http://www.gnu.org/software/gsasl/.
15 This system does not provide sources of data for authentication, so
16 careful use needs to be made of the conditions in Exim. Note that
17 this can not yet be used as a drop-in replacement for Cyrus SASL, as
18 Exim is currently unable to construct strings with embedded NULs for
19 use as keys in lookups against sasldb2.
21 2. New authenticator driver, "heimdal_gssapi". Server-only.
22 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
23 is no longer honoured for setuid programs by Heimdal. Use the
24 "server_keytab" option to point to the keytab.
26 3. The "pkg-config" system can now be used when building Exim to reference
27 cflags and library information for lookups and authenticators, rather
28 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
29 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
30 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
32 4. New expansion variable $tls_bits.
34 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
35 be joined together with ASCII NUL characters to construct the key to pass
42 1. New options for the ratelimit ACL condition: /count= and /unique=.
43 The /noupdate option has been replaced by a /readonly option.
45 2. The SMTP transport's protocol option may now be set to "smtps", to
46 use SSL-on-connect outbound.
48 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
49 there is a problem talking to the AV scanner, or the AV scanner running.
51 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
52 and check if the search item is a member of the list. This does not
53 support named lists, but does subject the list part to string expansion.
55 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
56 built, Exim no longer performs string expansion on the second string of
57 the match_* expansion conditions: "match_address", "match_domain",
58 "match_ip" & "match_local_part". Named lists can still be used.
64 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
65 or off in the resolver library.
71 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
72 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
73 libraries. The following global options have been added in support of
74 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
75 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
77 2. The pipe transport now takes a boolean option, "freeze_signal", default
78 false. When true, if the external delivery command exits on a signal then
79 Exim will freeze the message in the queue, instead of generating a bounce.
81 3. Log filenames may now use %M as an escape, instead of %D (still available).
82 The %M pattern expands to yyyymm, providing month-level resolution.
84 4. The $message_linecount variable is now updated for the maildir_tag option,
85 in the same way as $message_size, to reflect the real number of lines,
86 including any header additions or removals from transport.
88 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
89 Exim now selects entries randomly, to better scale in a cluster setup.
95 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
96 the flaw permitted the Exim run-time user to cause root to append to
97 arbitrary files of the attacker's choosing, with the content based
98 on content supplied by the attacker.
100 2. Exim now supports loading some lookup types at run-time, using your
101 platform's dlopen() functionality. This has limited platform support
102 and the intention is not to support every variant, it's limited to
103 dlopen(). This permits the main Exim binary to not be linked against
104 all the libraries needed for all the lookup types.
110 NOTE: this version is not guaranteed backwards-compatible, please read the
111 items below carefully
113 1. A new main configuration option, "openssl_options", is available if Exim
114 is built with SSL support provided by OpenSSL. The option allows
115 administrators to specify OpenSSL options to be used on connections;
116 typically this is to set bug compatibility features which the OpenSSL
117 developers have not enabled by default. There may be security
118 consequences for certain options, so these should not be changed
121 2. A new pipe transport option, "permit_coredumps", may help with problem
122 diagnosis in some scenarios. Note that Exim is typically installed as
123 a setuid binary, which on most OSes will inhibit coredumps by default,
124 so that safety mechanism would have to be overridden for this option to
125 be able to take effect.
127 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
128 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
129 Note that this switches Exim to use a new API ("INSTREAM") and a future
130 release of ClamAV will remove support for the old API ("STREAM").
132 The av_scanner option, when set to "clamd", now takes an optional third
133 part, "local", which causes Exim to pass a filename to ClamAV instead of
134 the file content. This is the same behaviour as when clamd is pointed at
135 a Unix-domain socket. For example:
137 av_scanner = clamd:192.0.2.3 1234:local
139 ClamAV's ExtendedDetectionInfo response format is now handled.
141 4. There is now a -bmalware option, restricted to admin users. This option
142 takes one parameter, a filename, and scans that file with Exim's
143 malware-scanning framework. This is intended purely as a debugging aid
144 to ensure that Exim's scanning is working, not to replace other tools.
145 Note that the ACL framework is not invoked, so if av_scanner references
146 ACL variables without a fallback then this will fail.
148 5. There is a new expansion operator, "reverse_ip", which will reverse IP
149 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
151 ${reverse_ip:192.0.2.4}
153 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
154 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
156 6. There is a new ACL control called "debug", to enable debug logging.
157 This allows selective logging of certain incoming transactions within
158 production environments, with some care. It takes two options, "tag"
159 and "opts"; "tag" is included in the filename of the log and "opts"
160 is used as per the -d<options> command-line option. Examples, which
161 don't all make sense in all contexts:
164 control = debug/tag=.$sender_host_address
165 control = debug/opts=+expand+acl
166 control = debug/tag=.$message_exim_id/opts=+expand
168 7. It has always been implicit in the design and the documentation that
169 "the Exim user" is not root. src/EDITME said that using root was
170 "very strongly discouraged". This is not enough to keep people from
171 shooting themselves in the foot in days when many don't configure Exim
172 themselves but via package build managers. The security consequences of
173 running various bits of network code are severe if there should be bugs in
174 them. As such, the Exim user may no longer be root. If configured
175 statically, Exim will refuse to build. If configured as ref:user then Exim
176 will exit shortly after start-up. If you must shoot yourself in the foot,
177 then henceforth you will have to maintain your own local patches to strip
180 8. There is a new expansion operator, bool_lax{}. Where bool{} uses the ACL
181 condition logic to determine truth/failure and will fail to expand many
182 strings, bool_lax{} uses the router condition logic, where most strings
184 Note: bool{00} is false, bool_lax{00} is true.
186 9. Routers now support multiple "condition" tests,
188 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
189 Setting this allows an admin to define which entry in the tcpwrappers
190 config file will be used to control access to the daemon. This option
191 is only available when Exim is built with USE_TCP_WRAPPERS. The
192 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
195 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
196 the Exim run-time user, instead of root.
198 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
199 is forced on. This is mitigated by the new build option
200 TRUSTED_CONFIG_LIST which defines a list of configuration files which
201 are trusted; one per line. If a config file is owned by root and matches
202 a pathname in the list, then it may be invoked by the Exim build-time
203 user without Exim relinquishing root privileges.
205 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
206 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
207 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
208 include the main config. As a transition mechanism, we are temporarily
209 providing a work-around: the new build option WHITELIST_D_MACROS provides
210 a colon-separated list of macro names which may be overridden by the Exim
211 run-time user. The values of these macros are constrained to the regex
212 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
218 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
219 writable, the other to locking of MBX folders (not mbox).
221 2. MySQL stored procedures are now supported.
223 3. The dkim_domain transport option is now a list, not a single string, and
224 messages will be signed for each element in the list (discarding
227 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
228 in the presence of multiple character strings within the RR. Prior to 4.70,
229 only the first string would be returned. The dnsdb lookup now, by default,
230 preserves the pre-4.70 semantics, but also now takes an extended output
231 separator specification. The separator can be followed by a semicolon, to
232 concatenate the individual text strings together with no join character,
233 or by a comma and a second separator character, in which case the text
234 strings within a TXT record are joined on that second character.
235 Administrators are reminded that DNS provides no ordering guarantees
236 between multiple records in an RRset. For example:
238 foo.example. IN TXT "a" "b" "c"
239 foo.example. IN TXT "d" "e" "f"
241 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
242 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
243 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
249 1. Native DKIM support without an external library.
250 (Note that if no action to prevent it is taken, a straight upgrade will
251 result in DKIM verification of all signed incoming emails. See spec
252 for details on conditionally disabling)
254 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
256 3. There is now a bool{} expansion condition which maps certain strings to
257 true/false condition values (most likely of use in conjunction with the
258 and{} expansion operator).
260 4. The $spam_score, $spam_bar and $spam_report variables are now available
263 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
264 options, provided that Exim is invoked by an admin_user.
266 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
267 which increases compatibility with older clients at the cost of decreased
268 security. Don't set this unless you need to support such clients.
270 7. There is a new expansion operator, ${randint:...} which will produce a
271 "random" number less than the supplied integer. This randomness is
272 not guaranteed to be cryptographically strong, but depending upon how
273 Exim was built may be better than the most naive schemes.
275 8. Exim now explicitly ensures that SHA256 is available when linked against
278 9. The transport_filter_timeout option now applies to SMTP transports too.
284 1. Preliminary DKIM support in Experimental.
290 1. The body_linecount and body_zerocount C variables are now exported in the
293 2. When a dnslists lookup succeeds, the key that was looked up is now placed
294 in $dnslist_matched. When the key is an IP address, it is not reversed in
295 this variable (though it is, of course, in the actual lookup). In simple
298 deny dnslists = spamhaus.example
300 the key is also available in another variable (in this case,
301 $sender_host_address). In more complicated cases, however, this is not
302 true. For example, using a data lookup might generate a dnslists lookup
305 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
307 If this condition succeeds, the value in $dnslist_matched might be
308 192.168.6.7 (for example).
310 3. Authenticators now have a client_condition option. When Exim is running as
311 a client, it skips an authenticator whose client_condition expansion yields
312 "0", "no", or "false". This can be used, for example, to skip plain text
313 authenticators when the connection is not encrypted by a setting such as:
315 client_condition = ${if !eq{$tls_cipher}{}}
317 Note that the 4.67 documentation states that $tls_cipher contains the
318 cipher used for incoming messages. In fact, during SMTP delivery, it
319 contains the cipher used for the delivery. The same is true for
322 4. There is now a -Mvc <message-id> option, which outputs a copy of the
323 message to the standard output, in RFC 2822 format. The option can be used
324 only by an admin user.
326 5. There is now a /noupdate option for the ratelimit ACL condition. It
327 computes the rate and checks the limit as normal, but it does not update
328 the saved data. This means that, in relevant ACLs, it is possible to lookup
329 the existence of a specified (or auto-generated) ratelimit key without
330 incrementing the ratelimit counter for that key.
332 In order for this to be useful, another ACL entry must set the rate
333 for the same key somewhere (otherwise it will always be zero).
338 # Read the rate; if it doesn't exist or is below the maximum
340 deny ratelimit = 100 / 5m / strict / noupdate
341 log_message = RATE: $sender_rate / $sender_rate_period \
342 (max $sender_rate_limit)
344 [... some other logic and tests...]
346 warn ratelimit = 100 / 5m / strict / per_cmd
347 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
348 (max $sender_rate_limit)
349 condition = ${if le{$sender_rate}{$sender_rate_limit}}
353 6. The variable $max_received_linelength contains the number of bytes in the
354 longest line that was received as part of the message, not counting the
355 line termination character(s).
357 7. Host lists can now include +ignore_defer and +include_defer, analagous to
358 +ignore_unknown and +include_unknown. These options should be used with
359 care, probably only in non-critical host lists such as whitelists.
361 8. There's a new option called queue_only_load_latch, which defaults true.
362 If set false when queue_only_load is greater than zero, Exim re-evaluates
363 the load for each incoming message in an SMTP session. Otherwise, once one
364 message is queued, the remainder are also.
366 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
367 cases when an SMTP session ends without sending QUIT. However, when Exim
368 itself is is bad trouble, such as being unable to write to its log files,
369 this ACL is not run, because it might try to do things (such as write to
370 log files) that make the situation even worse.
372 Like the QUIT ACL, this new ACL is provided to make it possible to gather
373 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
374 modifier is forbidden in this ACL.
376 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
377 to a string that indicates the reason for the termination of the SMTP
378 connection. The possible values are:
380 acl-drop Another ACL issued a "drop" command
381 bad-commands Too many unknown or non-mail commands
382 command-timeout Timeout while reading SMTP commands
383 connection-lost The SMTP connection has been lost
384 data-timeout Timeout while reading message data
385 local-scan-error The local_scan() function crashed
386 local-scan-timeout The local_scan() function timed out
387 signal-exit SIGTERM or SIGINT
388 synchronization-error SMTP synchronization error
389 tls-failed TLS failed to start
391 In most cases when an SMTP connection is closed without having received
392 QUIT, Exim sends an SMTP response message before actually closing the
393 connection. With the exception of acl-drop, the default message can be
394 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
395 "drop" verb in another ACL, it is the message from the other ACL that is
398 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
399 servers with individual queries. This is done by starting the query with
400 "servers=x:y:z;", where each item in the list may take one of two forms:
402 (1) If it is just a host name, the appropriate global option (mysql_servers
403 or pgsql_servers) is searched for a host of the same name, and the
404 remaining parameters (database, user, password) are taken from there.
406 (2) If it contains any slashes, it is taken as a complete parameter set.
408 The list of servers is used in exactly the same was as the global list.
409 Once a connection to a server has happened and a query has been
410 successfully executed, processing of the lookup ceases.
412 This feature is intended for use in master/slave situations where updates
413 are occurring, and one wants to update a master rather than a slave. If the
414 masters are in the list for reading, you might have:
416 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
418 In an updating lookup, you could then write
420 ${lookup mysql{servers=master; UPDATE ...}
422 If, on the other hand, the master is not to be used for reading lookups:
424 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
426 you can still update the master by
428 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
430 11. The message_body_newlines option (default FALSE, for backwards
431 compatibility) can be used to control whether newlines are present in
432 $message_body and $message_body_end. If it is FALSE, they are replaced by
439 1. There is a new log selector called smtp_no_mail, which is not included in
440 the default setting. When it is set, a line is written to the main log
441 whenever an accepted SMTP connection terminates without having issued a
444 2. When an item in a dnslists list is followed by = and & and a list of IP
445 addresses, the behaviour was not clear when the lookup returned more than
446 one IP address. This has been solved by the addition of == and =& for "all"
447 rather than the default "any" matching.
449 3. Up till now, the only control over which cipher suites GnuTLS uses has been
450 for the cipher algorithms. New options have been added to allow some of the
451 other parameters to be varied.
453 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
454 set, Exim compiles a runtime option called disable_fsync.
456 5. There is a new variable called $smtp_count_at_connection_start.
458 6. There's a new control called no_pipelining.
460 7. There are two new variables called $sending_ip_address and $sending_port.
461 These are set whenever an SMTP connection to another host has been set up.
463 8. The expansion of the helo_data option in the smtp transport now happens
464 after the connection to the server has been made.
466 9. There is a new expansion operator ${rfc2047d: that decodes strings that
467 are encoded as per RFC 2047.
469 10. There is a new log selector called "pid", which causes the current process
470 id to be added to every log line, in square brackets, immediately after the
473 11. Exim has been modified so that it flushes SMTP output before implementing
474 a delay in an ACL. It also flushes the output before performing a callout,
475 as this can take a substantial time. These behaviours can be disabled by
476 obeying control = no_delay_flush or control = no_callout_flush,
477 respectively, at some earlier stage of the connection.
479 12. There are two new expansion conditions that iterate over a list. They are
480 called forany and forall.
482 13. There's a new global option called dsn_from that can be used to vary the
483 contents of From: lines in bounces and other automatically generated
484 messages ("delivery status notifications" - hence the name of the option).
486 14. The smtp transport has a new option called hosts_avoid_pipelining.
488 15. By default, exigrep does case-insensitive matches. There is now a -I option
489 that makes it case-sensitive.
491 16. A number of new features ("addresses", "map", "filter", and "reduce") have
492 been added to string expansions to make it easier to process lists of
493 items, typically addresses.
495 17. There's a new ACL modifier called "continue". It does nothing of itself,
496 and processing of the ACL always continues with the next condition or
497 modifier. It is provided so that the side effects of expanding its argument
500 18. It is now possible to use newline and other control characters (those with
501 values less than 32, plus DEL) as separators in lists.
503 19. The exigrep utility now has a -v option, which inverts the matching
506 20. The host_find_failed option in the manualroute router can now be set to
513 No new features were added to 4.66.
519 No new features were added to 4.65.
525 1. ACL variables can now be given arbitrary names, as long as they start with
526 "acl_c" or "acl_m" (for connection variables and message variables), are at
527 least six characters long, with the sixth character being either a digit or
530 2. There is a new ACL modifier called log_reject_target. It makes it possible
531 to specify which logs are used for messages about ACL rejections.
533 3. There is a new authenticator called "dovecot". This is an interface to the
534 authentication facility of the Dovecot POP/IMAP server, which can support a
535 number of authentication methods.
537 4. The variable $message_headers_raw provides a concatenation of all the
538 messages's headers without any decoding. This is in contrast to
539 $message_headers, which does RFC2047 decoding on the header contents.
541 5. In a DNS black list, if two domain names, comma-separated, are given, the
542 second is used first to do an initial check, making use of any IP value
543 restrictions that are set. If there is a match, the first domain is used,
544 without any IP value restrictions, to get the TXT record.
546 6. All authenticators now have a server_condition option.
548 7. There is a new command-line option called -Mset. It is useful only in
549 conjunction with -be (that is, when testing string expansions). It must be
550 followed by a message id; Exim loads the given message from its spool
551 before doing the expansions.
553 8. Another similar new command-line option is called -bem. It operates like
554 -be except that it must be followed by the name of a file that contains a
557 9. When an address is delayed because of a 4xx response to a RCPT command, it
558 is now the combination of sender and recipient that is delayed in
559 subsequent queue runs until its retry time is reached.
561 10. Unary negation and the bitwise logical operators and, or, xor, not, and
562 shift, have been added to the eval: and eval10: expansion items.
564 11. The variables $interface_address and $interface_port have been renamed
565 as $received_ip_address and $received_port, to make it clear that they
566 relate to message reception rather than delivery. (The old names remain
567 available for compatibility.)
569 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
570 to vary the message that is sent when an SMTP command is accepted.
576 1. There is a new Boolean option called filter_prepend_home for the redirect
579 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
580 start of receiving a non-SMTP message, before any of the message has been
583 3. When an SMTP error message is specified in a "message" modifier in an ACL,
584 or in a :fail: or :defer: message in a redirect router, Exim now checks the
585 start of the message for an SMTP error code.
587 4. There is a new parameter for LDAP lookups called "referrals", which takes
588 one of the settings "follow" (the default) or "nofollow".
590 5. Version 20070721.2 of exipick now included, offering these new options:
592 After all other sorting options have bee processed, reverse order
593 before displaying messages (-R is synonym).
595 Randomize order of matching messages before displaying.
597 Instead of displaying the matching messages, display the sum
599 --sort <variable>[,<variable>...]
600 Before displaying matching messages, sort the messages according to
601 each messages value for each variable.
603 Negate the value for every test (returns inverse output from the
604 same criteria without --not).
610 1. The ${readsocket expansion item now supports Internet domain sockets as well
611 as Unix domain sockets. If the first argument begins "inet:", it must be of
612 the form "inet:host:port". The port is mandatory; it may be a number or the
613 name of a TCP port in /etc/services. The host may be a name, or it may be an
614 IP address. An ip address may optionally be enclosed in square brackets.
615 This is best for IPv6 addresses. For example:
617 ${readsocket{inet:[::1]:1234}{<request data>}...
619 Only a single host name may be given, but if looking it up yield more than
620 one IP address, they are each tried in turn until a connection is made. Once
621 a connection has been made, the behaviour is as for ${readsocket with a Unix
624 2. If a redirect router sets up file or pipe deliveries for more than one
625 incoming address, and the relevant transport has batch_max set greater than
626 one, a batch delivery now occurs.
628 3. The appendfile transport has a new option called maildirfolder_create_regex.
629 Its value is a regular expression. For a maildir delivery, this is matched
630 against the maildir directory; if it matches, Exim ensures that a
631 maildirfolder file is created alongside the new, cur, and tmp directories.
637 The documentation is up-to-date for the 4.61 release. Major new features since
638 the 4.60 release are:
640 . An option called disable_ipv6, to disable the use of IPv6 completely.
642 . An increase in the number of ACL variables to 20 of each type.
644 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
645 $2, $3, (though those are still set) because the numeric variables get used
646 for other things in complicated expansions.
648 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
650 . It is possible to use setclassresources() on some BSD OS to control the
651 resources used in pipe deliveries.
653 . A new ACL modifier called add_header, which can be used with any verb.
655 . More errors are detectable in retry rules.
657 There are a number of other additions too.
663 The documentation is up-to-date for the 4.60 release. Major new features since
664 the 4.50 release are:
666 . Support for SQLite.
668 . Support for IGNOREQUOTA in LMTP.
670 . Extensions to the "submission mode" features.
672 . Support for Client SMTP Authorization (CSA).
674 . Support for ratelimiting hosts and users.
676 . New expansion items to help with the BATV "prvs" scheme.
678 . A "match_ip" condition, that matches an IP address against a list.
680 There are many more minor changes.