1 $Cambridge: exim/doc/doc-txt/NewStuff,v 1.142 2007/02/14 15:33:40 ph10 Exp $
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.
14 1. There is a new log selector called smtp_no_mail, which is not included in
15 the default setting. When it is set, a line is written to the main log
16 whenever an accepted SMTP connection terminates without having issued a
17 MAIL command. This includes both the case when the connection is dropped,
18 and the case when QUIT is used. Note that it does not include cases where
19 the connection is rejected right at the start (by an ACL, or because there
20 are too many connections, or whatever). These cases already have their own
23 The log line that is written contains the identity of the client in the
24 usual way, followed by D= and a time, which records the duration of the
25 connection. If the connection was authenticated, this fact is logged
26 exactly as it is for an incoming message, with an A= item. If the
27 connection was encrypted, CV=, DN=, and X= items may appear as they do for
28 an incoming message, controlled by the same logging options.
30 Finally, if any SMTP commands were issued during the connection, a C= item
31 is added to the line, listing the commands that were used. For example,
35 shows that the client issued QUIT straight after EHLO. If there were fewer
36 than 20 commands, they are all listed. If there were more than 20 commands,
37 the last 20 are listed, preceded by "...". However, with the default
38 setting of 10 for smtp_accep_max_nonmail, the connection will in any case
39 be aborted before 20 non-mail commands are processed.
41 2. When an item in a dnslists list is followed by = and & and a list of IP
42 addresses, in order to restrict the match to specific results from the DNS
43 lookup, the behaviour was not clear when the lookup returned more than one
44 IP address. For example, consider the condition
46 dnslists = a.b.c=127.0.0.1
48 What happens if the DNS lookup for the incoming IP address yields both
49 127.0.0.1 and 127.0.0.2 by means of two separate DNS records? Is the
50 condition true because at least one given value was found, or is it false
51 because at least one of the found values was not listed? And how does this
52 affect negated conditions?
54 The behaviour of = and & has not been changed; however, the text below
55 documents it more clearly. In addition, two new additional conditions (==
56 and =&) have been added, to permit the "other" behaviour to be configured.
58 A DNS lookup may yield more than one record. Thus, the result of the lookup
59 for a dnslists check may yield more than one IP address. The question then
60 arises as to whether all the looked up addresses must be listed, or whether
61 just one is good enough. Both possibilities are provided for:
63 . If = or & is used, the condition is true if any one of the looked up
64 IP addresses matches one of the listed addresses. Consider:
66 dnslists = a.b.c=127.0.0.1
68 If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is
69 true because 127.0.0.1 matches.
71 . If == or =& is used, the condition is true only if every one of the
72 looked up IP addresses matches one of the listed addresses. Consider:
74 dnslists = a.b.c==127.0.0.1
76 If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is
77 false because 127.0.0.2 is not listed. You would need to have
79 dnslists = a.b.c==127.0.0.1,127.0.0.2
81 for the condition to be true.
83 When ! is used to negate IP address matching, it inverts the result, giving
84 the precise opposite of the behaviour above. Thus:
86 . If != or !& is used, the condition is true if none of the looked up IP
87 addresses matches one of the listed addresses. Consider:
89 dnslists = a.b.c!&0.0.0.1
91 If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is
92 false because 127.0.0.1 matches.
94 . If !== or !=& is used, the condition is true there is at least one looked
95 up IP address that does not match. Consider:
97 dnslists = a.b.c!=&0.0.0.1
99 If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is
100 true, because 127.0.0.2 does not match. You would need to have
102 dnslists = a.b.c!=&0.0.0.1,0.0.0.2
104 for the condition to be false.
106 When the DNS lookup yields only a single IP address, there is no difference
107 between = and == and between & and =&.
109 3. Up till now, the only control over which cipher suites GnuTLS uses has been
110 for the cipher algorithms. New options have been added to allow some of the
111 other parameters to be varied. Here is complete documentation for the
114 GnuTLS allows the caller to specify separate lists of permitted key
115 exchange methods, main cipher algorithms, and MAC algorithms. These may be
116 used in any combination to form a specific cipher suite. This is unlike
117 OpenSSL, where complete cipher names can be passed to its control function.
118 GnuTLS also allows a list of acceptable protocols to be supplied.
120 For compatibility with OpenSSL, the tls_require_ciphers option can be set
121 to complete cipher suite names such as RSA_ARCFOUR_SHA, but for GnuTLS this
122 option controls only the cipher algorithms. Exim searches each item in the
123 list for the name of an available algorithm. For example, if the list
124 contains RSA_AES_SHA, then AES is recognized, and the behaviour is exactly
125 the same as if just AES were given.
127 There are additional options called gnutls_require_kx, gnutls_require_mac,
128 and gnutls_require_protocols that can be used to restrict the key exchange
129 methods, MAC algorithms, and protocols, respectively. These options are
130 ignored if OpenSSL is in use.
132 All four options are available as global options, controlling how Exim
133 behaves as a server, and also as options of the smtp transport, controlling
134 how Exim behaves as a client. All the values are string expanded. After
135 expansion, the values must be colon-separated lists, though the separator
136 can be changed in the usual way.
138 Each of the four lists starts out with a default set of algorithms. If the
139 first item in one of the "require" options does _not_ start with an
140 exclamation mark, all the default items are deleted. In this case, only
141 those that are explicitly specified can be used. If the first item in one
142 of the "require" items _does_ start with an exclamation mark, the defaults
143 are left on the list.
145 Then, any item that starts with an exclamation mark causes the relevant
146 entry to be removed from the list, and any item that does not start with an
147 exclamation mark causes a new entry to be added to the list. Unrecognized
148 items in the list are ignored. Thus:
150 tls_require_ciphers = !ARCFOUR
152 allows all the defaults except ARCFOUR, whereas
154 tls_require_ciphers = AES : 3DES
156 allows only cipher suites that use AES or 3DES. For tls_require_ciphers
157 the recognized names are AES_256, AES_128, AES (both of the preceding),
158 3DES, ARCFOUR_128, ARCFOUR_40, and ARCFOUR (both of the preceding). The
159 default list does not contain all of these; it just has AES_256, AES_128,
160 3DES, and ARCFOUR_128.
162 For gnutls_require_kx, the recognized names are DHE_RSA, RSA (which
163 includes DHE_RSA), DHE_DSS, and DHE (which includes both DHE_RSA and
164 DHE_DSS). The default list contains RSA, DHE_DSS, DHE_RSA.
166 For gnutls_require_mac, the recognized names are SHA (synonym SHA1), and
167 MD5. The default list contains SHA, MD5.
169 For gnutls_require_protocols, the recognized names are TLS1 and SSL3.
170 The default list contains TLS1, SSL3.
172 In a server, the order of items in these lists is unimportant. The server
173 will advertise the availability of all the relevant cipher suites. However,
174 in a client, the order in the tls_require_ciphers list specifies a
175 preference order for the cipher algorithms. The first one in the client's
176 list that is also advertised by the server is tried first.
178 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. You must
179 not set this option unless you really, really, really understand what you
180 are doing. No pre-compiled distributions of Exim should ever set this
181 option. When it is set, Exim compiles a runtime option called
182 disable_fsync. If this is set true, Exim no longer calls fsync() to force
183 updated files' data to be written to disc. Unexpected events such as
184 crashes and power outages may cause data to be lost or scrambled. Beware.
186 When ENABLE_DISABLE_FSYNC is not set, a reference to disable_fsync in a
187 runtime configuration generates an "unknown option" error.
189 5. There is a new variable called $smtp_count_at_connection_start. The name
190 is deliberately long, in order to emphasize what the contents are. This
191 variable is set greater than zero only in processes spawned by the Exim
192 daemon for handling incoming SMTP connections. When the daemon accepts a
193 new connection, it increments this variable. A copy of the variable is
194 passed to the child process that handles the connection, but its value is
195 fixed, and never changes. It is only an approximation of how many incoming
196 connections there actually are, because many other connections may come and
197 go while a single connection is being processed. When a child process
198 terminates, the daemon decrements the variable.
200 6. There's a new control called no_pipelining, which does what its name
201 suggests. It turns off the advertising of the PIPELINING extension to SMTP.
202 To be useful, this control must be obeyed before Exim sends its response to
203 an EHLO command. Therefore, it should normally appear in an ACL controlled
204 by acl_smtp_connect or acl_smtp_helo.
206 7. There are two new variables called $sending_ip_address and $sending_port.
207 These are set whenever an SMTP connection to another host has been set up,
208 and they contain the IP address and port of the local interface that is
209 being used. They are of interest only on hosts that have more than on IP
210 address that want to take on different personalities depending on which one
213 8. The expansion of the helo_data option in the smtp transport now happens
214 after the connection to the server has been made. This means that it can
215 use the value of $sending_ip_address (see 7 above) to vary the text of the
216 message. For example, if you want the string that is used for helo_data to
217 be obtained by a DNS lookup of the interface address, you could use this:
219 helo_data = ${lookup dnsdb{ptr=$sending_ip_address}{$value}\
222 The use of helo_data applies both to sending messages and when doing
225 9. There is a new expansion operator ${rfc2047d: that decodes strings that
226 are encoded as per RFC 2047. Binary zero bytes are replaced by question
227 marks. Characters are converted into the character set defined by
228 headers_charset. Overlong RFC 2047 "words" are not recognized unless
229 check_rfc2047_length is set false.
231 10. There is a new log selector called "pid", which causes the current process
232 id to be added to every log line, in square brackets, immediately after the
235 11. Exim has been modified so that it flushes SMTP output before implementing
236 a delay in an ACL. It also flushes the output before performing a callout,
237 as this can take a substantial time. These behaviours can be disabled by
238 obeying control = no_delay_flush or control = no_callout_flush,
239 respectively, at some earlier stage of the connection. The effect of the
240 new default behaviour is to disable the PIPELINING optimization in these
241 situations, in order to avoid unexpected timeouts in clients.
243 12. There are two new expansion conditions that iterate over a list. They are
244 called forany and forall, and they are used like this:
246 ${if forany{<a list>}{<a condition>}{<yes-string>}{<no-string>}}
247 ${if forall{<a list>}{<a condition>}{<yes-string>}{<no-string>}}
249 The first argument is expanded, and the result is treated as a list. By
250 default, the list separator is a colon, but it can be changed by the normal
251 method. The second argument is interpreted as a condition that is to be
252 applied to each item in the list in turn. During the interpretation of the
253 condition, the current list item is placed in a variable called $item.
255 - For forany, interpretation stops if the condition is true for any item,
256 and the yes-string is then expanded. If the condition is false for all
257 items in the list, the no-string is expanded.
259 - For forall, interpration stops if the condition is false for any item,
260 and the no-string is then expanded. If the condition is true for all
261 items in the list, the yes-string is expanded.
263 Note that negation of forany means that the condition must be false for all
264 items for the overall condition to succeed, and negation of forall means
265 that the condition must be false for at least one item.
267 In this example, the list separator is changed to a comma:
269 ${if forany{<, $recipients}{match{$item}{^user3@}}{yes}{no}}
271 Outside a forany/forall condition, the value of $item is an empty string.
272 Its value is saved and restored while forany/forall is being processed, to
273 enable these expansion items to be nested.
275 13. There's a new global option called dsn_from that can be used to vary the
276 contents of From: lines in bounces and other automatically generated
277 messages ("delivery status notifications" - hence the name of the option).
278 The default setting is:
280 dsn_from = Mail Delivery System <Mailer-Daemon@$qualify_domain>
282 The value is expanded every time it is needed. If the expansion fails, a
283 panic is logged, and the default setting is used.
285 14. The smtp transport has a new option called hosts_avoid_pipelining. It can
286 be used to suppress the use of PIPELINING to certain hosts, while still
287 supporting the other SMTP extensions (cf hosts_avoid_tls).
289 15. By default, exigrep does case-insensitive matches. There is now a -I option
290 that makes it case-sensitive. This may give a performance improvement when
291 searching large log files. Without -I, the Perl pattern matches use the /i
292 option; with -I they don't. In both cases it is possible to change the case
293 sensitivity within the pattern using (?i) or (?-i).
295 16. A number of new features have been added to string expansions to make it
296 easier to process lists of items, typically addresses. These are as
299 * ${addresses:<string>}
301 The string (after expansion) is interpreted as a list of addresses in RFC
302 2822 format, such as can be found in a To: or Cc: header line. The
303 operative address (local-part@domain) is extracted from each item, and the
304 result of the expansion is a colon-separated list, with appropriate
305 doubling of colons should any happen to be present in the email addresses.
306 Syntactically invalid RFC2822 address items are omitted from the output.
308 It is possible to specify a character other than colon for the output
309 separator by starting the string with > followed by the new separator
310 character. For example:
312 ${addresses:>& The Boss <ceo@up.stairs>, sec@base.ment (dogsbody)}
314 expands to "ceo@up.stairs&sec@base.ment". Compare ${address (singular),
315 which extracts the working address from a single RFC2822 address.
317 * ${map{<string1>}{<string2>}}
319 After expansion, <string1> is interpreted as a list, colon-separated by
320 default, but the separator can be changed in the usual way. For each item
321 in this list, its value is place in $item, and then <string2> is expanded
322 and added to the output as an item in a new list. The separator used for
323 the output list is the same as the one used for the input, but is not
324 included in the output. For example:
326 ${map{a:b:c}{[$item]}} ${map{<- x-y-z}{($item)}}
328 expands to "[a]:[b]:[c] (x)-(y)-(z)". At the end of the expansion, the
329 value of $item is restored to what it was before.
331 * ${filter{<string1>}{<condition>}}
333 After expansion, <string1> is interpreted as a list, colon-separated by
334 default, but the separator can be changed in the usual way. For each item
335 in this list, its value is place in $item, and then the condition is
336 evaluated. If the condition is true, $item is added to the output as an
337 item in a new list; if the condition is false, the item is discarded. The
338 separator used for the output list is the same as the one used for the
339 input, but is not included in the output. For example:
341 ${filter{a:b:c}{!eq{$item}{b}}
343 yields "a:c". At the end of the expansion, the value of $item is restored
344 to what it was before.
346 * ${reduce{<string1>}{<string2>}{<string3>}}
348 The ${reduce expansion operation reduces a list to a single, scalar string.
349 After expansion, <string1> is interpreted as a list, colon-separated by
350 default, but the separator can be changed in the usual way. Then <string2>
351 is expanded and assigned to the $value variable. After this, each item in
352 the <string1> list is assigned to $item in turn, and <string3> is expanded
353 for each of them. The result of that expansion is assigned to $value before
354 the next iteration. When the end of the list is reached, the final value of
355 $value is added to the expansion string. The ${reduce expansion item can be
356 used in a number of ways. For example, to add up a list of numbers:
358 ${reduce {<, 1,2,3}{0}{${eval:$value+$item}}}
360 The result of that expansion would be "6". The maximum of a list of numbers
363 ${reduce {3:0:9:4:6}{0}{${if >{$item}{$value}{$item}{$value}}}}
365 At the end of a ${reduce expansion, the values of $item and $value is
366 restored to what they were before.
368 17. There's a new ACL modifier called "continue". It does nothing of itself,
369 and processing of the ACL always continues with the next condition or
370 modifier. It is provided so that the side effects of expanding its argument
371 can be used. Typically this would be for updating a database. It is really
372 just a syntactic tidiness, because the following two lines have the same
375 continue = <some expansion>
376 condition = ${if eq{0}{<some expansion>}{true}{true}}
382 No new features were added to 4.66.
388 No new features were added to 4.65.
394 1. ACL variables can now be given arbitrary names, as long as they start with
395 "acl_c" or "acl_m" (for connection variables and message variables), are at
396 least six characters long, with the sixth character being either a digit or
399 2. There is a new ACL modifier called log_reject_target. It makes it possible
400 to specify which logs are used for messages about ACL rejections.
402 3. There is a new authenticator called "dovecot". This is an interface to the
403 authentication facility of the Dovecot POP/IMAP server, which can support a
404 number of authentication methods.
406 4. The variable $message_headers_raw provides a concatenation of all the
407 messages's headers without any decoding. This is in contrast to
408 $message_headers, which does RFC2047 decoding on the header contents.
410 5. In a DNS black list, if two domain names, comma-separated, are given, the
411 second is used first to do an initial check, making use of any IP value
412 restrictions that are set. If there is a match, the first domain is used,
413 without any IP value restrictions, to get the TXT record.
415 6. All authenticators now have a server_condition option.
417 7. There is a new command-line option called -Mset. It is useful only in
418 conjunction with -be (that is, when testing string expansions). It must be
419 followed by a message id; Exim loads the given message from its spool
420 before doing the expansions.
422 8. Another similar new command-line option is called -bem. It operates like
423 -be except that it must be followed by the name of a file that contains a
426 9. When an address is delayed because of a 4xx response to a RCPT command, it
427 is now the combination of sender and recipient that is delayed in
428 subsequent queue runs until its retry time is reached.
430 10. Unary negation and the bitwise logical operators and, or, xor, not, and
431 shift, have been added to the eval: and eval10: expansion items.
433 11. The variables $interface_address and $interface_port have been renamed
434 as $received_ip_address and $received_port, to make it clear that they
435 relate to message reception rather than delivery. (The old names remain
436 available for compatibility.)
438 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
439 to vary the message that is sent when an SMTP command is accepted.
445 1. There is a new Boolean option called filter_prepend_home for the redirect
448 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
449 start of receiving a non-SMTP message, before any of the message has been
452 3. When an SMTP error message is specified in a "message" modifier in an ACL,
453 or in a :fail: or :defer: message in a redirect router, Exim now checks the
454 start of the message for an SMTP error code.
456 4. There is a new parameter for LDAP lookups called "referrals", which takes
457 one of the settings "follow" (the default) or "nofollow".
459 5. Version 20070721.2 of exipick now included, offering these new options:
461 After all other sorting options have bee processed, reverse order
462 before displaying messages (-R is synonym).
464 Randomize order of matching messages before displaying.
466 Instead of displaying the matching messages, display the sum
468 --sort <variable>[,<variable>...]
469 Before displaying matching messages, sort the messages according to
470 each messages value for each variable.
472 Negate the value for every test (returns inverse output from the
473 same criteria without --not).
479 1. The ${readsocket expansion item now supports Internet domain sockets as well
480 as Unix domain sockets. If the first argument begins "inet:", it must be of
481 the form "inet:host:port". The port is mandatory; it may be a number or the
482 name of a TCP port in /etc/services. The host may be a name, or it may be an
483 IP address. An ip address may optionally be enclosed in square brackets.
484 This is best for IPv6 addresses. For example:
486 ${readsocket{inet:[::1]:1234}{<request data>}...
488 Only a single host name may be given, but if looking it up yield more than
489 one IP address, they are each tried in turn until a connection is made. Once
490 a connection has been made, the behaviour is as for ${readsocket with a Unix
493 2. If a redirect router sets up file or pipe deliveries for more than one
494 incoming address, and the relevant transport has batch_max set greater than
495 one, a batch delivery now occurs.
497 3. The appendfile transport has a new option called maildirfolder_create_regex.
498 Its value is a regular expression. For a maildir delivery, this is matched
499 against the maildir directory; if it matches, Exim ensures that a
500 maildirfolder file is created alongside the new, cur, and tmp directories.
506 The documentation is up-to-date for the 4.61 release. Major new features since
507 the 4.60 release are:
509 . An option called disable_ipv6, to disable the use of IPv6 completely.
511 . An increase in the number of ACL variables to 20 of each type.
513 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
514 $2, $3, (though those are still set) because the numeric variables get used
515 for other things in complicated expansions.
517 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
519 . It is possible to use setclassresources() on some BSD OS to control the
520 resources used in pipe deliveries.
522 . A new ACL modifier called add_header, which can be used with any verb.
524 . More errors are detectable in retry rules.
526 There are a number of other additions too.
532 The documentation is up-to-date for the 4.60 release. Major new features since
533 the 4.50 release are:
535 . Support for SQLite.
537 . Support for IGNOREQUOTA in LMTP.
539 . Extensions to the "submission mode" features.
541 . Support for Client SMTP Authorization (CSA).
543 . Support for ratelimiting hosts and users.
545 . New expansion items to help with the BATV "prvs" scheme.
547 . A "match_ip" condition, that matches an IP address against a list.
549 There are many more minor changes.