Flush SMTP output buffer before "delay" in an ACL; add control =
[exim.git] / doc / doc-txt / NewStuff
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047bdd8c 1$Cambridge: exim/doc/doc-txt/NewStuff,v 1.135 2007/02/05 12:35:46 ph10 Exp $
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2
3New Features in Exim
4--------------------
5
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6This file contains descriptions of new features that have been added to Exim.
7Before a formal release, there may be quite a lot of detail so that people can
8test from the snapshots or the CVS before the documentation is updated. Once
9the documentation is updated, this file is reduced to a short list.
10
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11Version 4.67
12------------
13
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
21 log lines.
22
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.
29
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,
32
33 C=EHLO,QUIT
34
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.
40
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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
45
46 dnslists = a.b.c=127.0.0.1
47
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?
53
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.
57
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:
62
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:
65
66 dnslists = a.b.c=127.0.0.1
67
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.
70
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:
73
74 dnslists = a.b.c==127.0.0.1
75
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
78
79 dnslists = a.b.c==127.0.0.1,127.0.0.2
80
81 for the condition to be true.
82
83 When ! is used to negate IP address matching, it inverts the result, giving
84 the precise opposite of the behaviour above. Thus:
85
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:
88
89 dnslists = a.b.c!&0.0.0.1
90
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.
93
94 . If !== or !=& is used, the condition is true there is at least one looked
95 up IP address that does not match. Consider:
96
97 dnslists = a.b.c!=&0.0.0.1
98
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
101
102 dnslists = a.b.c!=&0.0.0.1,0.0.0.2
103
104 for the condition to be false.
105
106 When the DNS lookup yields only a single IP address, there is no difference
107 between = and == and between & and =&.
108
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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
112 available features:
113
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.
119
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.
126
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.
131
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.
137
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.
144
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:
149
150 tls_require_ciphers = !ARCFOUR
151
152 allows all the defaults except ARCFOUR, whereas
153
154 tls_require_ciphers = AES : 3DES
155
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.
161
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.
165
166 For gnutls_require_mac, the recognized names are SHA (synonym SHA1), and
167 MD5. The default list contains SHA, MD5.
168
169 For gnutls_require_protocols, the recognized names are TLS1 and SSL3.
170 The default list contains TLS1, SSL3.
171
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.
177
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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.
185
186 When ENABLE_DISABLE_FSYNC is not set, a reference to disable_fsync in a
187 runtime configuration generates an "unknown option" error.
188
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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.
199
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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.
205
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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
211 is being used.
212
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:
218
219 helo_data = ${lookup dnsdb{ptr=$sending_ip_address}{$value}\
220 {$primary_hostname}}
221
222 The use of helo_data applies both to sending messages and when doing
223 callouts.
224
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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.
230
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23110. 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
233 time and date.
234
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23511. Exim has been modified so that it flushes SMTP output before implementing
236 a delay in an ACL. This behaviour can be disabled by obeying control =
237 no_delay_flush at some earlier point.
238
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239
240Version 4.66
241------------
242
243No new features were added to 4.66.
244
245
246Version 4.65
247------------
248
249No new features were added to 4.65.
250
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251
252Version 4.64
253------------
254
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255 1. ACL variables can now be given arbitrary names, as long as they start with
256 "acl_c" or "acl_m" (for connection variables and message variables), are at
257 least six characters long, with the sixth character being either a digit or
883335dc 258 an underscore.
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259
260 2. There is a new ACL modifier called log_reject_target. It makes it possible
883335dc 261 to specify which logs are used for messages about ACL rejections.
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262
263 3. There is a new authenticator called "dovecot". This is an interface to the
264 authentication facility of the Dovecot POP/IMAP server, which can support a
883335dc 265 number of authentication methods.
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266
267 4. The variable $message_headers_raw provides a concatenation of all the
268 messages's headers without any decoding. This is in contrast to
269 $message_headers, which does RFC2047 decoding on the header contents.
270
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271 5. In a DNS black list, if two domain names, comma-separated, are given, the
272 second is used first to do an initial check, making use of any IP value
273 restrictions that are set. If there is a match, the first domain is used,
274 without any IP value restrictions, to get the TXT record.
af561417 275
883335dc 276 6. All authenticators now have a server_condition option.
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277
278 7. There is a new command-line option called -Mset. It is useful only in
279 conjunction with -be (that is, when testing string expansions). It must be
280 followed by a message id; Exim loads the given message from its spool
883335dc 281 before doing the expansions.
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282
283 8. Another similar new command-line option is called -bem. It operates like
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284 -be except that it must be followed by the name of a file that contains a
285 message.
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286
287 9. When an address is delayed because of a 4xx response to a RCPT command, it
288 is now the combination of sender and recipient that is delayed in
883335dc 289 subsequent queue runs until its retry time is reached.
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290
29110. Unary negation and the bitwise logical operators and, or, xor, not, and
883335dc 292 shift, have been added to the eval: and eval10: expansion items.
48c7f9e2 293
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29411. The variables $interface_address and $interface_port have been renamed
295 as $received_ip_address and $received_port, to make it clear that they
296 relate to message reception rather than delivery. (The old names remain
297 available for compatibility.)
298
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29912. The "message" modifier can now be used on "accept" and "discard" acl verbs
300 to vary the message that is sent when an SMTP command is accepted.
4e88a19f 301
495ae4b0 302
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303Version 4.63
304------------
305
3061. There is a new Boolean option called filter_prepend_home for the redirect
38a0a95f 307 router.
4608d683 308
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3092. There is a new acl, set by acl_not_smtp_start, which is run right at the
310 start of receiving a non-SMTP message, before any of the message has been
38a0a95f 311 read.
45b91596 312
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3133. When an SMTP error message is specified in a "message" modifier in an ACL,
314 or in a :fail: or :defer: message in a redirect router, Exim now checks the
38a0a95f 315 start of the message for an SMTP error code.
a5bd321b 316
6ec97b1b 3174. There is a new parameter for LDAP lookups called "referrals", which takes
38a0a95f 318 one of the settings "follow" (the default) or "nofollow".
6ec97b1b 319
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3205. Version 20070721.2 of exipick now included, offering these new options:
321 --reverse
322 After all other sorting options have bee processed, reverse order
323 before displaying messages (-R is synonym).
324 --random
325 Randomize order of matching messages before displaying.
326 --size
327 Instead of displaying the matching messages, display the sum
328 of their sizes.
329 --sort <variable>[,<variable>...]
330 Before displaying matching messages, sort the messages according to
331 each messages value for each variable.
332 --not
333 Negate the value for every test (returns inverse output from the
334 same criteria without --not).
335
4608d683 336
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337Version 4.62
338------------
339
3401. The ${readsocket expansion item now supports Internet domain sockets as well
341 as Unix domain sockets. If the first argument begins "inet:", it must be of
342 the form "inet:host:port". The port is mandatory; it may be a number or the
343 name of a TCP port in /etc/services. The host may be a name, or it may be an
344 IP address. An ip address may optionally be enclosed in square brackets.
345 This is best for IPv6 addresses. For example:
346
347 ${readsocket{inet:[::1]:1234}{<request data>}...
348
349 Only a single host name may be given, but if looking it up yield more than
350 one IP address, they are each tried in turn until a connection is made. Once
351 a connection has been made, the behaviour is as for ${readsocket with a Unix
352 domain socket.
353
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3542. If a redirect router sets up file or pipe deliveries for more than one
355 incoming address, and the relevant transport has batch_max set greater than
356 one, a batch delivery now occurs.
357
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3583. The appendfile transport has a new option called maildirfolder_create_regex.
359 Its value is a regular expression. For a maildir delivery, this is matched
360 against the maildir directory; if it matches, Exim ensures that a
361 maildirfolder file is created alongside the new, cur, and tmp directories.
362
1cce3af8 363
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364Version 4.61
365------------
366
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367The documentation is up-to-date for the 4.61 release. Major new features since
368the 4.60 release are:
369
370. An option called disable_ipv6, to disable the use of IPv6 completely.
371
372. An increase in the number of ACL variables to 20 of each type.
373
374. A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
375 $2, $3, (though those are still set) because the numeric variables get used
376 for other things in complicated expansions.
377
843a41e8 378. The default for rfc1413_query_timeout has been changed from 30s to 5s.
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379
380. It is possible to use setclassresources() on some BSD OS to control the
381 resources used in pipe deliveries.
382
383. A new ACL modifier called add_header, which can be used with any verb.
384
385. More errors are detectable in retry rules.
386
387There are a number of other additions too.
71fafd95 388
7e66e54d 389
425ae40f 390Version 4.60
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391------------
392
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393The documentation is up-to-date for the 4.60 release. Major new features since
394the 4.50 release are:
1a46a8c5 395
425ae40f 396. Support for SQLite.
1a46a8c5 397
425ae40f 398. Support for IGNOREQUOTA in LMTP.
1a46a8c5 399
425ae40f 400. Extensions to the "submission mode" features.
1a46a8c5 401
425ae40f 402. Support for Client SMTP Authorization (CSA).
1a46a8c5 403
425ae40f 404. Support for ratelimiting hosts and users.
b5aea5e1 405
425ae40f 406. New expansion items to help with the BATV "prvs" scheme.
b5aea5e1 407
425ae40f 408. A "match_ip" condition, that matches an IP address against a list.
35edf2ff 409
425ae40f 410There are many more minor changes.
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411
412****