No longer permit the exim user to be root. Fixes: #752
[exim.git] / doc / doc-txt / NewStuff
1 $Cambridge: exim/doc/doc-txt/NewStuff,v 1.172 2010/06/06 02:46:13 pdp Exp $
3 New Features in Exim
4 --------------------
6 This file contains descriptions of new features that have been added to Exim.
7 Before a formal release, there may be quite a lot of detail so that people can
8 test from the snapshots or the CVS before the documentation is updated. Once
9 the documentation is updated, this file is reduced to a short list.
12 Version 4.73
13 ------------
15 1. A new main configuration option, "openssl_options", is available if Exim
16 is built with SSL support provided by OpenSSL. The option allows
17 administrators to specify OpenSSL options to be used on connections;
18 typically this is to set bug compatibility features which the OpenSSL
19 developers have not enabled by default. There may be security
20 consequences for certain options, so these should not be changed
21 frivolously.
23 2. A new pipe transport option, "permit_coredumps", may help with problem
24 diagnosis in some scenarios. Note that Exim is typically installed as
25 a setuid binary, which on most OSes will inhibit coredumps by default,
26 so that safety mechanism would have to be overriden for this option to
27 be able to take effect.
29 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
30 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
31 Note that this switches Exim to use a new API ("INSTREAM") and a future
32 release of ClamAV will remove support for the old API ("STREAM").
34 The av_scanner option, when set to "clamd", now takes an optional third
35 part, "local", which causes Exim to pass a filename to ClamAV instead of
36 the file content. This is the same behaviour as when clamd is pointed at
37 a Unix-domain socket. For example:
39 av_scanner = clamd: 1234:local
41 4. There is now a -bmalware option, restricted to admin users. This option
42 takes one parameter, a filename, and scans that file with Exim's
43 malware-scanning framework. This is intended purely as a debugging aid
44 to ensure that Exim's scanning is working, not to replace other tools.
46 5. There is a new expansion operator, "reverse_ip", which will reverse IP
47 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
49 ${reverse_ip:}
50 ->
51 ${reverse_ip:2001:0db8:c42:9:1:abcd:}
52 ->
54 6. There is a new ACL control called "debug", to enable debug logging.
55 This allows selective logging of certain incoming transactions within
56 production environments, with some care. It takes two options, "tag"
57 and "opts"; "tag" is included in the filename of the log and "opts"
58 is used as per the -d<options> command-line option. Examples, which
59 don't all make sense in all contexts:
61 control = debug
62 control = debug/tag=.$sender_host_address
63 control = debug/opts=+expand+acl
64 control = debug/tag=.$message_exim_id/opts=+expand
66 7. It has always been implicit in the design and the documentation that
67 "the Exim user" is not root. src/EDITME said that using root was
68 "very strongly discouraged". This is not enough to keep people from
69 shooting themselves in the foot in days when many don't configure Exim
70 themselves but via package build managers. The security consequences of
71 running various bits of network code are severe if there should be bugs in
72 them. As such, the Exim user may no longer be root. If configured
73 statically, Exim will refuse to build. If configured as ref:user then Exim
74 will exit shortly after start-up. If you must shoot yourself in the foot,
75 then henceforth you will have to maintain your own local patches to strip
76 the safeties off.
79 Version 4.72
80 ------------
82 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
83 writable, the other to locking of MBX folders (not mbox).
85 2. MySQL stored procedures are now supported.
87 3. The dkim_domain transport option is now a list, not a single string, and
88 messages will be signed for each element in the list (discarding
89 duplicates).
91 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
92 in the presence of multiple character strings within the RR. Prior to 4.70,
93 only the first string would be returned. The dnsdb lookup now, by default,
94 preserves the pre-4.70 semantics, but also now takes an extended output
95 separator specification. The separator can be followed by a semicolon, to
96 concatenate the individual text strings together with no join character,
97 or by a comma and a second separator character, in which case the text
98 strings within a TXT record are joined on that second character.
99 Administrators are reminded that DNS provides no ordering guarantees
100 between multiple records in an RRset. For example:
102 foo.example. IN TXT "a" "b" "c"
103 foo.example. IN TXT "d" "e" "f"
105 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
106 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
107 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
110 Version 4.70 / 4.71
111 -------------------
113 1. Native DKIM support without an external library.
114 (Note that if no action to prevent it is taken, a straight upgrade will
115 result in DKIM verification of all signed incoming emails. See spec
116 for details on conditionally disabling)
118 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
120 3. There is now a bool{} expansion condition which maps certain strings to
121 true/false condition values (most likely of use in conjunction with the
122 and{} expansion operator).
124 4. The $spam_score, $spam_bar and $spam_report variables are now available
125 at delivery time.
127 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
128 options, provided that Exim is invoked by an admin_user.
130 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
131 which increases compatibility with older clients at the cost of decreased
132 security. Don't set this unless you need to support such clients.
134 7. There is a new expansion operator, ${randint:...} which will produce a
135 "random" number less than the supplied integer. This randomness is
136 not guaranteed to be cryptographically strong, but depending upon how
137 Exim was built may be better than the most naive schemes.
139 8. Exim now explicitly ensures that SHA256 is available when linked against
140 OpenSSL.
142 9. The transport_filter_timeout option now applies to SMTP transports too.
145 Version 4.69
146 ------------
148 1. Preliminary DKIM support in Experimental.
151 Version 4.68
152 ------------
154 1. The body_linecount and body_zerocount C variables are now exported in the
155 local_scan API.
157 2. When a dnslists lookup succeeds, the key that was looked up is now placed
158 in $dnslist_matched. When the key is an IP address, it is not reversed in
159 this variable (though it is, of course, in the actual lookup). In simple
160 cases, for example:
162 deny dnslists = spamhaus.example
164 the key is also available in another variable (in this case,
165 $sender_host_address). In more complicated cases, however, this is not
166 true. For example, using a data lookup might generate a dnslists lookup
167 like this:
169 deny dnslists = spamhaus.example/<|||...
171 If this condition succeeds, the value in $dnslist_matched might be
172 (for example).
174 3. Authenticators now have a client_condition option. When Exim is running as
175 a client, it skips an authenticator whose client_condition expansion yields
176 "0", "no", or "false". This can be used, for example, to skip plain text
177 authenticators when the connection is not encrypted by a setting such as:
179 client_condition = ${if !eq{$tls_cipher}{}}
181 Note that the 4.67 documentation states that $tls_cipher contains the
182 cipher used for incoming messages. In fact, during SMTP delivery, it
183 contains the cipher used for the delivery. The same is true for
184 $tls_peerdn.
186 4. There is now a -Mvc <message-id> option, which outputs a copy of the
187 message to the standard output, in RFC 2822 format. The option can be used
188 only by an admin user.
190 5. There is now a /noupdate option for the ratelimit ACL condition. It
191 computes the rate and checks the limit as normal, but it does not update
192 the saved data. This means that, in relevant ACLs, it is possible to lookup
193 the existence of a specified (or auto-generated) ratelimit key without
194 incrementing the ratelimit counter for that key.
196 In order for this to be useful, another ACL entry must set the rate
197 for the same key somewhere (otherwise it will always be zero).
199 Example:
201 acl_check_connect:
202 # Read the rate; if it doesn't exist or is below the maximum
203 # we update it below
204 deny ratelimit = 100 / 5m / strict / noupdate
205 log_message = RATE: $sender_rate / $sender_rate_period \
206 (max $sender_rate_limit)
208 [... some other logic and tests...]
210 warn ratelimit = 100 / 5m / strict / per_cmd
211 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
212 (max $sender_rate_limit)
213 condition = ${if le{$sender_rate}{$sender_rate_limit}}
215 accept
217 6. The variable $max_received_linelength contains the number of bytes in the
218 longest line that was received as part of the message, not counting the
219 line termination character(s).
221 7. Host lists can now include +ignore_defer and +include_defer, analagous to
222 +ignore_unknown and +include_unknown. These options should be used with
223 care, probably only in non-critical host lists such as whitelists.
225 8. There's a new option called queue_only_load_latch, which defaults true.
226 If set false when queue_only_load is greater than zero, Exim re-evaluates
227 the load for each incoming message in an SMTP session. Otherwise, once one
228 message is queued, the remainder are also.
230 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
231 cases when an SMTP session ends without sending QUIT. However, when Exim
232 itself is is bad trouble, such as being unable to write to its log files,
233 this ACL is not run, because it might try to do things (such as write to
234 log files) that make the situation even worse.
236 Like the QUIT ACL, this new ACL is provided to make it possible to gather
237 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
238 modifier is forbidden in this ACL.
240 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
241 to a string that indicates the reason for the termination of the SMTP
242 connection. The possible values are:
244 acl-drop Another ACL issued a "drop" command
245 bad-commands Too many unknown or non-mail commands
246 command-timeout Timeout while reading SMTP commands
247 connection-lost The SMTP connection has been lost
248 data-timeout Timeout while reading message data
249 local-scan-error The local_scan() function crashed
250 local-scan-timeout The local_scan() function timed out
251 signal-exit SIGTERM or SIGINT
252 synchronization-error SMTP synchronization error
253 tls-failed TLS failed to start
255 In most cases when an SMTP connection is closed without having received
256 QUIT, Exim sends an SMTP response message before actually closing the
257 connection. With the exception of acl-drop, the default message can be
258 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
259 "drop" verb in another ACL, it is the message from the other ACL that is
260 used.
262 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
263 servers with individual queries. This is done by starting the query with
264 "servers=x:y:z;", where each item in the list may take one of two forms:
266 (1) If it is just a host name, the appropriate global option (mysql_servers
267 or pgsql_servers) is searched for a host of the same name, and the
268 remaining parameters (database, user, password) are taken from there.
270 (2) If it contains any slashes, it is taken as a complete parameter set.
272 The list of servers is used in exactly the same was as the global list.
273 Once a connection to a server has happened and a query has been
274 successfully executed, processing of the lookup ceases.
276 This feature is intended for use in master/slave situations where updates
277 are occurring, and one wants to update a master rather than a slave. If the
278 masters are in the list for reading, you might have:
280 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
282 In an updating lookup, you could then write
284 ${lookup mysql{servers=master; UPDATE ...}
286 If, on the other hand, the master is not to be used for reading lookups:
288 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
290 you can still update the master by
292 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
294 11. The message_body_newlines option (default FALSE, for backwards
295 compatibility) can be used to control whether newlines are present in
296 $message_body and $message_body_end. If it is FALSE, they are replaced by
297 spaces.
300 Version 4.67
301 ------------
303 1. There is a new log selector called smtp_no_mail, which is not included in
304 the default setting. When it is set, a line is written to the main log
305 whenever an accepted SMTP connection terminates without having issued a
306 MAIL command.
308 2. When an item in a dnslists list is followed by = and & and a list of IP
309 addresses, the behaviour was not clear when the lookup returned more than
310 one IP address. This has been solved by the addition of == and =& for "all"
311 rather than the default "any" matching.
313 3. Up till now, the only control over which cipher suites GnuTLS uses has been
314 for the cipher algorithms. New options have been added to allow some of the
315 other parameters to be varied.
317 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
318 set, Exim compiles a runtime option called disable_fsync.
320 5. There is a new variable called $smtp_count_at_connection_start.
322 6. There's a new control called no_pipelining.
324 7. There are two new variables called $sending_ip_address and $sending_port.
325 These are set whenever an SMTP connection to another host has been set up.
327 8. The expansion of the helo_data option in the smtp transport now happens
328 after the connection to the server has been made.
330 9. There is a new expansion operator ${rfc2047d: that decodes strings that
331 are encoded as per RFC 2047.
333 10. There is a new log selector called "pid", which causes the current process
334 id to be added to every log line, in square brackets, immediately after the
335 time and date.
337 11. Exim has been modified so that it flushes SMTP output before implementing
338 a delay in an ACL. It also flushes the output before performing a callout,
339 as this can take a substantial time. These behaviours can be disabled by
340 obeying control = no_delay_flush or control = no_callout_flush,
341 respectively, at some earlier stage of the connection.
343 12. There are two new expansion conditions that iterate over a list. They are
344 called forany and forall.
346 13. There's a new global option called dsn_from that can be used to vary the
347 contents of From: lines in bounces and other automatically generated
348 messages ("delivery status notifications" - hence the name of the option).
350 14. The smtp transport has a new option called hosts_avoid_pipelining.
352 15. By default, exigrep does case-insensitive matches. There is now a -I option
353 that makes it case-sensitive.
355 16. A number of new features ("addresses", "map", "filter", and "reduce") have
356 been added to string expansions to make it easier to process lists of
357 items, typically addresses.
359 17. There's a new ACL modifier called "continue". It does nothing of itself,
360 and processing of the ACL always continues with the next condition or
361 modifier. It is provided so that the side effects of expanding its argument
362 can be used.
364 18. It is now possible to use newline and other control characters (those with
365 values less than 32, plus DEL) as separators in lists.
367 19. The exigrep utility now has a -v option, which inverts the matching
368 condition.
370 20. The host_find_failed option in the manualroute router can now be set to
371 "ignore".
374 Version 4.66
375 ------------
377 No new features were added to 4.66.
380 Version 4.65
381 ------------
383 No new features were added to 4.65.
386 Version 4.64
387 ------------
389 1. ACL variables can now be given arbitrary names, as long as they start with
390 "acl_c" or "acl_m" (for connection variables and message variables), are at
391 least six characters long, with the sixth character being either a digit or
392 an underscore.
394 2. There is a new ACL modifier called log_reject_target. It makes it possible
395 to specify which logs are used for messages about ACL rejections.
397 3. There is a new authenticator called "dovecot". This is an interface to the
398 authentication facility of the Dovecot POP/IMAP server, which can support a
399 number of authentication methods.
401 4. The variable $message_headers_raw provides a concatenation of all the
402 messages's headers without any decoding. This is in contrast to
403 $message_headers, which does RFC2047 decoding on the header contents.
405 5. In a DNS black list, if two domain names, comma-separated, are given, the
406 second is used first to do an initial check, making use of any IP value
407 restrictions that are set. If there is a match, the first domain is used,
408 without any IP value restrictions, to get the TXT record.
410 6. All authenticators now have a server_condition option.
412 7. There is a new command-line option called -Mset. It is useful only in
413 conjunction with -be (that is, when testing string expansions). It must be
414 followed by a message id; Exim loads the given message from its spool
415 before doing the expansions.
417 8. Another similar new command-line option is called -bem. It operates like
418 -be except that it must be followed by the name of a file that contains a
419 message.
421 9. When an address is delayed because of a 4xx response to a RCPT command, it
422 is now the combination of sender and recipient that is delayed in
423 subsequent queue runs until its retry time is reached.
425 10. Unary negation and the bitwise logical operators and, or, xor, not, and
426 shift, have been added to the eval: and eval10: expansion items.
428 11. The variables $interface_address and $interface_port have been renamed
429 as $received_ip_address and $received_port, to make it clear that they
430 relate to message reception rather than delivery. (The old names remain
431 available for compatibility.)
433 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
434 to vary the message that is sent when an SMTP command is accepted.
437 Version 4.63
438 ------------
440 1. There is a new Boolean option called filter_prepend_home for the redirect
441 router.
443 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
444 start of receiving a non-SMTP message, before any of the message has been
445 read.
447 3. When an SMTP error message is specified in a "message" modifier in an ACL,
448 or in a :fail: or :defer: message in a redirect router, Exim now checks the
449 start of the message for an SMTP error code.
451 4. There is a new parameter for LDAP lookups called "referrals", which takes
452 one of the settings "follow" (the default) or "nofollow".
454 5. Version 20070721.2 of exipick now included, offering these new options:
455 --reverse
456 After all other sorting options have bee processed, reverse order
457 before displaying messages (-R is synonym).
458 --random
459 Randomize order of matching messages before displaying.
460 --size
461 Instead of displaying the matching messages, display the sum
462 of their sizes.
463 --sort <variable>[,<variable>...]
464 Before displaying matching messages, sort the messages according to
465 each messages value for each variable.
466 --not
467 Negate the value for every test (returns inverse output from the
468 same criteria without --not).
471 Version 4.62
472 ------------
474 1. The ${readsocket expansion item now supports Internet domain sockets as well
475 as Unix domain sockets. If the first argument begins "inet:", it must be of
476 the form "inet:host:port". The port is mandatory; it may be a number or the
477 name of a TCP port in /etc/services. The host may be a name, or it may be an
478 IP address. An ip address may optionally be enclosed in square brackets.
479 This is best for IPv6 addresses. For example:
481 ${readsocket{inet:[::1]:1234}{<request data>}...
483 Only a single host name may be given, but if looking it up yield more than
484 one IP address, they are each tried in turn until a connection is made. Once
485 a connection has been made, the behaviour is as for ${readsocket with a Unix
486 domain socket.
488 2. If a redirect router sets up file or pipe deliveries for more than one
489 incoming address, and the relevant transport has batch_max set greater than
490 one, a batch delivery now occurs.
492 3. The appendfile transport has a new option called maildirfolder_create_regex.
493 Its value is a regular expression. For a maildir delivery, this is matched
494 against the maildir directory; if it matches, Exim ensures that a
495 maildirfolder file is created alongside the new, cur, and tmp directories.
498 Version 4.61
499 ------------
501 The documentation is up-to-date for the 4.61 release. Major new features since
502 the 4.60 release are:
504 . An option called disable_ipv6, to disable the use of IPv6 completely.
506 . An increase in the number of ACL variables to 20 of each type.
508 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
509 $2, $3, (though those are still set) because the numeric variables get used
510 for other things in complicated expansions.
512 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
514 . It is possible to use setclassresources() on some BSD OS to control the
515 resources used in pipe deliveries.
517 . A new ACL modifier called add_header, which can be used with any verb.
519 . More errors are detectable in retry rules.
521 There are a number of other additions too.
524 Version 4.60
525 ------------
527 The documentation is up-to-date for the 4.60 release. Major new features since
528 the 4.50 release are:
530 . Support for SQLite.
532 . Support for IGNOREQUOTA in LMTP.
534 . Extensions to the "submission mode" features.
536 . Support for Client SMTP Authorization (CSA).
538 . Support for ratelimiting hosts and users.
540 . New expansion items to help with the BATV "prvs" scheme.
542 . A "match_ip" condition, that matches an IP address against a list.
544 There are many more minor changes.
546 ****