SECURITY: DMARC uses From header untrusted data
[exim.git] / doc / doc-txt / NewStuff
1 New Features in Exim
2 --------------------
3
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.
8
9 Version 4.82
10 ------------
11
12 1. New command-line option -bI:sieve will list all supported sieve extensions
13 of this Exim build on standard output, one per line.
14 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
15 query this to establish the correct list to include in the protocol's
16 SIEVE capability line.
17
18 2. If the -n option is combined with the -bP option, then the name of an
19 emitted option is not output, only the value (if visible to you).
20 For instance, "exim -n -bP pid_file_path" should just emit a pathname
21 followed by a newline, and no other text.
22
23 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
24 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
25 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
26 acceptable for security. (Option accepted but ignored if using OpenSSL).
27 Defaults to 1024, the old value. May be lowered only to 512, or raised as
28 far as you like. Raising this may hinder TLS interoperability with other
29 sites and is not currently recommended. Lowering this will permit you to
30 establish a TLS session which is not as secure as you might like.
31
32 Unless you really know what you are doing, leave it alone.
33
34 4. If not built with DISABLE_DNSSEC, Exim now has the main option
35 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
36 to send the DO flag to your recursive resolver. If you have a recursive
37 resolver, which can set the Authenticated Data (AD) flag in results, Exim
38 can now detect this. Exim does not perform validation itself, instead
39 relying upon a trusted path to the resolver.
40
41 Current status: work-in-progress; $sender_host_dnssec variable added.
42
43 5. DSCP support for outbound connections: on a transport using the smtp driver,
44 set "dscp = ef", for instance, to cause the connections to have the relevant
45 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
46
47 Similarly for inbound connections, there is a new control modifier, dscp,
48 so "warn control = dscp/ef" in the connect ACL, or after authentication.
49
50 Supported values depend upon system libraries. "exim -bI:dscp" to list the
51 ones Exim knows of. You can also set a raw number 0..0x3F.
52
53 6. The -G command-line flag is no longer ignored; it is now equivalent to an
54 ACL setting "control = suppress_local_fixups". The -L command-line flag
55 is now accepted and forces use of syslog, with the provided tag as the
56 process name. A few other flags used by Sendmail are now accepted and
57 ignored.
58
59 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
60 ACL modifier; works for single-recipient mails which are recieved on and
61 deliverable via SMTP. Using the connection made for a recipient verify,
62 if requested before the verify, or a new one made for the purpose while
63 the inbound connection is still active. The bulk of the mail item is copied
64 direct from the inbound socket to the outbound (as well as the spool file).
65 When the source notifies the end of data, the data acceptance by the destination
66 is negociated before the acceptance is sent to the source. If the destination
67 does not accept the mail item, for example due to content-scanning, the item
68 is not accepted from the source and therefore there is no need to generate
69 a bounce mail. This is of benefit when providing a secondary-MX service.
70 The downside is that delays are under the control of the ultimate destination
71 system not your own.
72
73 The Recieved-by: header on items delivered by cutthrough is generated
74 early in reception rather than at the end; this will affect any timestamp
75 included. The log line showing delivery is recorded before that showing
76 reception; it uses a new ">>" tag instead of "=>".
77
78 To support the feature, verify-callout connections can now use ESMTP and TLS.
79 The usual smtp transport options are honoured, plus a (new, default everything)
80 hosts_verify_avoid_tls.
81
82 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
83 for specific access to the information for each connection. The old names
84 are present for now but deprecated.
85
86 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
87
88 8. New expansion operators ${listnamed:name} to get the content of a named list
89 and ${listcount:string} to count the items in a list.
90
91 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
92 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
93 modules. For some situations this is desirable, but we expect admin in
94 those situations to know they want the feature. More commonly, it means
95 that GUI user modules get loaded and are broken by the setuid Exim being
96 unable to access files specified in environment variables and passed
97 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
98 unless this new option is set.
99
100 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
101 so have also added a build option which can be used to build Exim with GnuTLS
102 but without trying to use any kind of PKCS11 support. Uncomment this in the
103 Local/Makefile:
104
105 AVOID_GNUTLS_PKCS11=yes
106
107 10. The "acl = name" condition on an ACL now supports optional arguments.
108 New expansion item "${acl {name}{arg}...}" and expansion condition
109 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
110 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
111 Variable $acl_narg contains the number of arguments. If the ACL sets
112 a "message =" value this becomes the result of the expansion item,
113 or the value of $value for the expansion condition. If the ACL returns
114 accept the expansion condition is true; if reject, false. A defer
115 return results in a forced fail.
116
117 11. Routers and transports can now have multiple headers_add and headers_remove
118 option lines. The concatenated list is used.
119
120 12. New ACL modifier "remove_header" can remove headers before message gets
121 handled by routers/transports.
122
123 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
124 "aaaa" and "a" lookups is done and the full set of results returned.
125
126 14. New expansion variable $headers_added with content from ACL add_header
127 modifier (but not yet added to messsage).
128
129 15. New 8bitmime status logging option for received messages. Log field "M8S".
130
131 16. New authenticated_sender logging option, adding to log field "A".
132
133 17. New expansion variables $router_name and $transport_name. Useful
134 particularly for debug_print as -bt commandline option does not
135 require privilege whereas -d does.
136
137 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
138 proposed extension to SMTP from Eric Hall.
139
140 19. The pipe transport has gained the force_command option, to allow
141 decorating commands from user .forward pipe aliases with prefix
142 wrappers, for instance.
143
144 20. Callout connections can now AUTH; the same controls as normal delivery
145 connections apply.
146
147 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
148 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
149 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
150 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
151 dmarc_status. It adds new control flags dmarc_disable_verify and
152 dmarc_enable_forensic.
153
154 22. Add expansion variable $authenticated_fail_id, which is the username
155 provided to the authentication method which failed. It is available
156 for use in subsequent ACL processing (typically quit or notquit ACLs).
157
158 23. New ACL modifer "udpsend" can construct a UDP packet to send to a given
159 UDP host and port.
160
161 24. New ${hexquote:..string..} expansion operator converts non-printable
162 characters in the string to \xNN form.
163
164 25. Experimental TPDA (Transport Post Delivery Action) function added.
165 Patch provided by Axel Rau.
166
167 26. Experimental Redis lookup added. Patch provided by Warren Baker.
168
169
170 Version 4.80
171 ------------
172
173 1. New authenticator driver, "gsasl". Server-only (at present).
174 This is a SASL interface, licensed under GPL, which can be found at
175 http://www.gnu.org/software/gsasl/.
176 This system does not provide sources of data for authentication, so
177 careful use needs to be made of the conditions in Exim.
178
179 2. New authenticator driver, "heimdal_gssapi". Server-only.
180 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
181 is no longer honoured for setuid programs by Heimdal. Use the
182 "server_keytab" option to point to the keytab.
183
184 3. The "pkg-config" system can now be used when building Exim to reference
185 cflags and library information for lookups and authenticators, rather
186 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
187 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
188 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
189
190 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
191 find the headers and libraries for PCRE.
192
193 4. New expansion variable $tls_bits.
194
195 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
196 be joined together with ASCII NUL characters to construct the key to pass
197 into the DBM library. Can be used with gsasl to access sasldb2 files as
198 used by Cyrus SASL.
199
200 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
201
202 Avoid release 1.0.1a if you can. Note that the default value of
203 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
204 increased susceptibility to attack. This may still have interoperability
205 implications for very old clients (see version 4.31 change 37) but
206 administrators can choose to make the trade-off themselves and restore
207 compatibility at the cost of session security.
208
209 7. Use of the new expansion variable $tls_sni in the main configuration option
210 tls_certificate will cause Exim to re-expand the option, if the client
211 sends the TLS Server Name Indication extension, to permit choosing a
212 different certificate; tls_privatekey will also be re-expanded. You must
213 still set these options to expand to valid files when $tls_sni is not set.
214
215 The SMTP Transport has gained the option tls_sni, which will set a hostname
216 for outbound TLS sessions, and set $tls_sni too.
217
218 A new log_selector, +tls_sni, has been added, to log received SNI values
219 for Exim as a server.
220
221 8. The existing "accept_8bitmime" option now defaults to true. This means
222 that Exim is deliberately not strictly RFC compliant. We're following
223 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
224 Those who disagree, or know that they are talking to mail servers that,
225 even today, are not 8-bit clean, need to turn off this option.
226
227 9. Exim can now be started with -bw (with an optional timeout, given as
228 -bw<timespec>). With this, stdin at startup is a socket that is
229 already listening for connections. This has a more modern name of
230 "socket activation", but forcing the activated socket to fd 0. We're
231 interested in adding more support for modern variants.
232
233 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
234 for numbers indicates multiplication by 1024^3.
235
236 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
237 gnutls_require_mac & gnutls_require_protocols are no longer supported.
238 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
239 string, documentation for which is at:
240 http://www.gnutls.org/manual/html_node/Priority-Strings.html
241
242 SNI support has been added to Exim's GnuTLS integration too.
243
244 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
245 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
246
247 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
248 is now available. If the contents of the file are valid, then Exim will
249 send that back in response to a TLS status request; this is OCSP Stapling.
250 Exim will not maintain the contents of the file in any way: administrators
251 are responsible for ensuring that it is up-to-date.
252
253 See "experimental-spec.txt" for more details.
254
255 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
256 identically to TXT record lookups.
257
258 14. New expansion variable $tod_epoch_l for higher-precision time.
259
260 15. New global option tls_dh_max_bits, defaulting to current value of NSS
261 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
262 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
263
264 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
265 Option can now be a path or an identifier for a standard prime.
266 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
267 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
268 primes.
269
270 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
271 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
272 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
273
274
275 Version 4.77
276 ------------
277
278 1. New options for the ratelimit ACL condition: /count= and /unique=.
279 The /noupdate option has been replaced by a /readonly option.
280
281 2. The SMTP transport's protocol option may now be set to "smtps", to
282 use SSL-on-connect outbound.
283
284 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
285 there is a problem talking to the AV scanner, or the AV scanner running.
286
287 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
288 and check if the search item is a member of the list. This does not
289 support named lists, but does subject the list part to string expansion.
290
291 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
292 built, Exim no longer performs string expansion on the second string of
293 the match_* expansion conditions: "match_address", "match_domain",
294 "match_ip" & "match_local_part". Named lists can still be used.
295
296
297 Version 4.76
298 ------------
299
300 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
301 or off in the resolver library.
302
303
304 Version 4.75
305 ------------
306
307 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
308 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
309 libraries. The following global options have been added in support of
310 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
311 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
312
313 2. The pipe transport now takes a boolean option, "freeze_signal", default
314 false. When true, if the external delivery command exits on a signal then
315 Exim will freeze the message in the queue, instead of generating a bounce.
316
317 3. Log filenames may now use %M as an escape, instead of %D (still available).
318 The %M pattern expands to yyyymm, providing month-level resolution.
319
320 4. The $message_linecount variable is now updated for the maildir_tag option,
321 in the same way as $message_size, to reflect the real number of lines,
322 including any header additions or removals from transport.
323
324 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
325 Exim now selects entries randomly, to better scale in a cluster setup.
326
327
328 Version 4.74
329 ------------
330
331 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
332 the flaw permitted the Exim run-time user to cause root to append to
333 arbitrary files of the attacker's choosing, with the content based
334 on content supplied by the attacker.
335
336 2. Exim now supports loading some lookup types at run-time, using your
337 platform's dlopen() functionality. This has limited platform support
338 and the intention is not to support every variant, it's limited to
339 dlopen(). This permits the main Exim binary to not be linked against
340 all the libraries needed for all the lookup types.
341
342
343 Version 4.73
344 ------------
345
346 NOTE: this version is not guaranteed backwards-compatible, please read the
347 items below carefully
348
349 1. A new main configuration option, "openssl_options", is available if Exim
350 is built with SSL support provided by OpenSSL. The option allows
351 administrators to specify OpenSSL options to be used on connections;
352 typically this is to set bug compatibility features which the OpenSSL
353 developers have not enabled by default. There may be security
354 consequences for certain options, so these should not be changed
355 frivolously.
356
357 2. A new pipe transport option, "permit_coredumps", may help with problem
358 diagnosis in some scenarios. Note that Exim is typically installed as
359 a setuid binary, which on most OSes will inhibit coredumps by default,
360 so that safety mechanism would have to be overridden for this option to
361 be able to take effect.
362
363 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
364 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
365 Note that this switches Exim to use a new API ("INSTREAM") and a future
366 release of ClamAV will remove support for the old API ("STREAM").
367
368 The av_scanner option, when set to "clamd", now takes an optional third
369 part, "local", which causes Exim to pass a filename to ClamAV instead of
370 the file content. This is the same behaviour as when clamd is pointed at
371 a Unix-domain socket. For example:
372
373 av_scanner = clamd:192.0.2.3 1234:local
374
375 ClamAV's ExtendedDetectionInfo response format is now handled.
376
377 4. There is now a -bmalware option, restricted to admin users. This option
378 takes one parameter, a filename, and scans that file with Exim's
379 malware-scanning framework. This is intended purely as a debugging aid
380 to ensure that Exim's scanning is working, not to replace other tools.
381 Note that the ACL framework is not invoked, so if av_scanner references
382 ACL variables without a fallback then this will fail.
383
384 5. There is a new expansion operator, "reverse_ip", which will reverse IP
385 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
386
387 ${reverse_ip:192.0.2.4}
388 -> 4.2.0.192
389 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
390 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
391
392 6. There is a new ACL control called "debug", to enable debug logging.
393 This allows selective logging of certain incoming transactions within
394 production environments, with some care. It takes two options, "tag"
395 and "opts"; "tag" is included in the filename of the log and "opts"
396 is used as per the -d<options> command-line option. Examples, which
397 don't all make sense in all contexts:
398
399 control = debug
400 control = debug/tag=.$sender_host_address
401 control = debug/opts=+expand+acl
402 control = debug/tag=.$message_exim_id/opts=+expand
403
404 7. It has always been implicit in the design and the documentation that
405 "the Exim user" is not root. src/EDITME said that using root was
406 "very strongly discouraged". This is not enough to keep people from
407 shooting themselves in the foot in days when many don't configure Exim
408 themselves but via package build managers. The security consequences of
409 running various bits of network code are severe if there should be bugs in
410 them. As such, the Exim user may no longer be root. If configured
411 statically, Exim will refuse to build. If configured as ref:user then Exim
412 will exit shortly after start-up. If you must shoot yourself in the foot,
413 then henceforth you will have to maintain your own local patches to strip
414 the safeties off.
415
416 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
417 condition logic to determine truth/failure and will fail to expand many
418 strings, bool_lax{} uses the router condition logic, where most strings
419 do evaluate true.
420 Note: bool{00} is false, bool_lax{00} is true.
421
422 9. Routers now support multiple "condition" tests.
423
424 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
425 Setting this allows an admin to define which entry in the tcpwrappers
426 config file will be used to control access to the daemon. This option
427 is only available when Exim is built with USE_TCP_WRAPPERS. The
428 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
429 build option.
430
431 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
432 the Exim run-time user, instead of root.
433
434 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
435 is forced on. This is mitigated by the new build option
436 TRUSTED_CONFIG_LIST which defines a list of configuration files which
437 are trusted; one per line. If a config file is owned by root and matches
438 a pathname in the list, then it may be invoked by the Exim build-time
439 user without Exim relinquishing root privileges.
440
441 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
442 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
443 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
444 include the main config. As a transition mechanism, we are temporarily
445 providing a work-around: the new build option WHITELIST_D_MACROS provides
446 a colon-separated list of macro names which may be overridden by the Exim
447 run-time user. The values of these macros are constrained to the regex
448 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
449
450
451 Version 4.72
452 ------------
453
454 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
455 writable, the other to locking of MBX folders (not mbox).
456
457 2. MySQL stored procedures are now supported.
458
459 3. The dkim_domain transport option is now a list, not a single string, and
460 messages will be signed for each element in the list (discarding
461 duplicates).
462
463 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
464 in the presence of multiple character strings within the RR. Prior to 4.70,
465 only the first string would be returned. The dnsdb lookup now, by default,
466 preserves the pre-4.70 semantics, but also now takes an extended output
467 separator specification. The separator can be followed by a semicolon, to
468 concatenate the individual text strings together with no join character,
469 or by a comma and a second separator character, in which case the text
470 strings within a TXT record are joined on that second character.
471 Administrators are reminded that DNS provides no ordering guarantees
472 between multiple records in an RRset. For example:
473
474 foo.example. IN TXT "a" "b" "c"
475 foo.example. IN TXT "d" "e" "f"
476
477 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
478 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
479 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
480
481
482 Version 4.70 / 4.71
483 -------------------
484
485 1. Native DKIM support without an external library.
486 (Note that if no action to prevent it is taken, a straight upgrade will
487 result in DKIM verification of all signed incoming emails. See spec
488 for details on conditionally disabling)
489
490 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
491
492 3. There is now a bool{} expansion condition which maps certain strings to
493 true/false condition values (most likely of use in conjunction with the
494 and{} expansion operator).
495
496 4. The $spam_score, $spam_bar and $spam_report variables are now available
497 at delivery time.
498
499 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
500 options, provided that Exim is invoked by an admin_user.
501
502 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
503 which increases compatibility with older clients at the cost of decreased
504 security. Don't set this unless you need to support such clients.
505
506 7. There is a new expansion operator, ${randint:...} which will produce a
507 "random" number less than the supplied integer. This randomness is
508 not guaranteed to be cryptographically strong, but depending upon how
509 Exim was built may be better than the most naive schemes.
510
511 8. Exim now explicitly ensures that SHA256 is available when linked against
512 OpenSSL.
513
514 9. The transport_filter_timeout option now applies to SMTP transports too.
515
516
517 Version 4.69
518 ------------
519
520 1. Preliminary DKIM support in Experimental.
521
522
523 Version 4.68
524 ------------
525
526 1. The body_linecount and body_zerocount C variables are now exported in the
527 local_scan API.
528
529 2. When a dnslists lookup succeeds, the key that was looked up is now placed
530 in $dnslist_matched. When the key is an IP address, it is not reversed in
531 this variable (though it is, of course, in the actual lookup). In simple
532 cases, for example:
533
534 deny dnslists = spamhaus.example
535
536 the key is also available in another variable (in this case,
537 $sender_host_address). In more complicated cases, however, this is not
538 true. For example, using a data lookup might generate a dnslists lookup
539 like this:
540
541 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
542
543 If this condition succeeds, the value in $dnslist_matched might be
544 192.168.6.7 (for example).
545
546 3. Authenticators now have a client_condition option. When Exim is running as
547 a client, it skips an authenticator whose client_condition expansion yields
548 "0", "no", or "false". This can be used, for example, to skip plain text
549 authenticators when the connection is not encrypted by a setting such as:
550
551 client_condition = ${if !eq{$tls_cipher}{}}
552
553 Note that the 4.67 documentation states that $tls_cipher contains the
554 cipher used for incoming messages. In fact, during SMTP delivery, it
555 contains the cipher used for the delivery. The same is true for
556 $tls_peerdn.
557
558 4. There is now a -Mvc <message-id> option, which outputs a copy of the
559 message to the standard output, in RFC 2822 format. The option can be used
560 only by an admin user.
561
562 5. There is now a /noupdate option for the ratelimit ACL condition. It
563 computes the rate and checks the limit as normal, but it does not update
564 the saved data. This means that, in relevant ACLs, it is possible to lookup
565 the existence of a specified (or auto-generated) ratelimit key without
566 incrementing the ratelimit counter for that key.
567
568 In order for this to be useful, another ACL entry must set the rate
569 for the same key somewhere (otherwise it will always be zero).
570
571 Example:
572
573 acl_check_connect:
574 # Read the rate; if it doesn't exist or is below the maximum
575 # we update it below
576 deny ratelimit = 100 / 5m / strict / noupdate
577 log_message = RATE: $sender_rate / $sender_rate_period \
578 (max $sender_rate_limit)
579
580 [... some other logic and tests...]
581
582 warn ratelimit = 100 / 5m / strict / per_cmd
583 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
584 (max $sender_rate_limit)
585 condition = ${if le{$sender_rate}{$sender_rate_limit}}
586
587 accept
588
589 6. The variable $max_received_linelength contains the number of bytes in the
590 longest line that was received as part of the message, not counting the
591 line termination character(s).
592
593 7. Host lists can now include +ignore_defer and +include_defer, analagous to
594 +ignore_unknown and +include_unknown. These options should be used with
595 care, probably only in non-critical host lists such as whitelists.
596
597 8. There's a new option called queue_only_load_latch, which defaults true.
598 If set false when queue_only_load is greater than zero, Exim re-evaluates
599 the load for each incoming message in an SMTP session. Otherwise, once one
600 message is queued, the remainder are also.
601
602 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
603 cases when an SMTP session ends without sending QUIT. However, when Exim
604 itself is is bad trouble, such as being unable to write to its log files,
605 this ACL is not run, because it might try to do things (such as write to
606 log files) that make the situation even worse.
607
608 Like the QUIT ACL, this new ACL is provided to make it possible to gather
609 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
610 modifier is forbidden in this ACL.
611
612 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
613 to a string that indicates the reason for the termination of the SMTP
614 connection. The possible values are:
615
616 acl-drop Another ACL issued a "drop" command
617 bad-commands Too many unknown or non-mail commands
618 command-timeout Timeout while reading SMTP commands
619 connection-lost The SMTP connection has been lost
620 data-timeout Timeout while reading message data
621 local-scan-error The local_scan() function crashed
622 local-scan-timeout The local_scan() function timed out
623 signal-exit SIGTERM or SIGINT
624 synchronization-error SMTP synchronization error
625 tls-failed TLS failed to start
626
627 In most cases when an SMTP connection is closed without having received
628 QUIT, Exim sends an SMTP response message before actually closing the
629 connection. With the exception of acl-drop, the default message can be
630 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
631 "drop" verb in another ACL, it is the message from the other ACL that is
632 used.
633
634 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
635 servers with individual queries. This is done by starting the query with
636 "servers=x:y:z;", where each item in the list may take one of two forms:
637
638 (1) If it is just a host name, the appropriate global option (mysql_servers
639 or pgsql_servers) is searched for a host of the same name, and the
640 remaining parameters (database, user, password) are taken from there.
641
642 (2) If it contains any slashes, it is taken as a complete parameter set.
643
644 The list of servers is used in exactly the same was as the global list.
645 Once a connection to a server has happened and a query has been
646 successfully executed, processing of the lookup ceases.
647
648 This feature is intended for use in master/slave situations where updates
649 are occurring, and one wants to update a master rather than a slave. If the
650 masters are in the list for reading, you might have:
651
652 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
653
654 In an updating lookup, you could then write
655
656 ${lookup mysql{servers=master; UPDATE ...}
657
658 If, on the other hand, the master is not to be used for reading lookups:
659
660 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
661
662 you can still update the master by
663
664 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
665
666 11. The message_body_newlines option (default FALSE, for backwards
667 compatibility) can be used to control whether newlines are present in
668 $message_body and $message_body_end. If it is FALSE, they are replaced by
669 spaces.
670
671
672 Version 4.67
673 ------------
674
675 1. There is a new log selector called smtp_no_mail, which is not included in
676 the default setting. When it is set, a line is written to the main log
677 whenever an accepted SMTP connection terminates without having issued a
678 MAIL command.
679
680 2. When an item in a dnslists list is followed by = and & and a list of IP
681 addresses, the behaviour was not clear when the lookup returned more than
682 one IP address. This has been solved by the addition of == and =& for "all"
683 rather than the default "any" matching.
684
685 3. Up till now, the only control over which cipher suites GnuTLS uses has been
686 for the cipher algorithms. New options have been added to allow some of the
687 other parameters to be varied.
688
689 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
690 set, Exim compiles a runtime option called disable_fsync.
691
692 5. There is a new variable called $smtp_count_at_connection_start.
693
694 6. There's a new control called no_pipelining.
695
696 7. There are two new variables called $sending_ip_address and $sending_port.
697 These are set whenever an SMTP connection to another host has been set up.
698
699 8. The expansion of the helo_data option in the smtp transport now happens
700 after the connection to the server has been made.
701
702 9. There is a new expansion operator ${rfc2047d: that decodes strings that
703 are encoded as per RFC 2047.
704
705 10. There is a new log selector called "pid", which causes the current process
706 id to be added to every log line, in square brackets, immediately after the
707 time and date.
708
709 11. Exim has been modified so that it flushes SMTP output before implementing
710 a delay in an ACL. It also flushes the output before performing a callout,
711 as this can take a substantial time. These behaviours can be disabled by
712 obeying control = no_delay_flush or control = no_callout_flush,
713 respectively, at some earlier stage of the connection.
714
715 12. There are two new expansion conditions that iterate over a list. They are
716 called forany and forall.
717
718 13. There's a new global option called dsn_from that can be used to vary the
719 contents of From: lines in bounces and other automatically generated
720 messages ("delivery status notifications" - hence the name of the option).
721
722 14. The smtp transport has a new option called hosts_avoid_pipelining.
723
724 15. By default, exigrep does case-insensitive matches. There is now a -I option
725 that makes it case-sensitive.
726
727 16. A number of new features ("addresses", "map", "filter", and "reduce") have
728 been added to string expansions to make it easier to process lists of
729 items, typically addresses.
730
731 17. There's a new ACL modifier called "continue". It does nothing of itself,
732 and processing of the ACL always continues with the next condition or
733 modifier. It is provided so that the side effects of expanding its argument
734 can be used.
735
736 18. It is now possible to use newline and other control characters (those with
737 values less than 32, plus DEL) as separators in lists.
738
739 19. The exigrep utility now has a -v option, which inverts the matching
740 condition.
741
742 20. The host_find_failed option in the manualroute router can now be set to
743 "ignore".
744
745
746 Version 4.66
747 ------------
748
749 No new features were added to 4.66.
750
751
752 Version 4.65
753 ------------
754
755 No new features were added to 4.65.
756
757
758 Version 4.64
759 ------------
760
761 1. ACL variables can now be given arbitrary names, as long as they start with
762 "acl_c" or "acl_m" (for connection variables and message variables), are at
763 least six characters long, with the sixth character being either a digit or
764 an underscore.
765
766 2. There is a new ACL modifier called log_reject_target. It makes it possible
767 to specify which logs are used for messages about ACL rejections.
768
769 3. There is a new authenticator called "dovecot". This is an interface to the
770 authentication facility of the Dovecot POP/IMAP server, which can support a
771 number of authentication methods.
772
773 4. The variable $message_headers_raw provides a concatenation of all the
774 messages's headers without any decoding. This is in contrast to
775 $message_headers, which does RFC2047 decoding on the header contents.
776
777 5. In a DNS black list, if two domain names, comma-separated, are given, the
778 second is used first to do an initial check, making use of any IP value
779 restrictions that are set. If there is a match, the first domain is used,
780 without any IP value restrictions, to get the TXT record.
781
782 6. All authenticators now have a server_condition option.
783
784 7. There is a new command-line option called -Mset. It is useful only in
785 conjunction with -be (that is, when testing string expansions). It must be
786 followed by a message id; Exim loads the given message from its spool
787 before doing the expansions.
788
789 8. Another similar new command-line option is called -bem. It operates like
790 -be except that it must be followed by the name of a file that contains a
791 message.
792
793 9. When an address is delayed because of a 4xx response to a RCPT command, it
794 is now the combination of sender and recipient that is delayed in
795 subsequent queue runs until its retry time is reached.
796
797 10. Unary negation and the bitwise logical operators and, or, xor, not, and
798 shift, have been added to the eval: and eval10: expansion items.
799
800 11. The variables $interface_address and $interface_port have been renamed
801 as $received_ip_address and $received_port, to make it clear that they
802 relate to message reception rather than delivery. (The old names remain
803 available for compatibility.)
804
805 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
806 to vary the message that is sent when an SMTP command is accepted.
807
808
809 Version 4.63
810 ------------
811
812 1. There is a new Boolean option called filter_prepend_home for the redirect
813 router.
814
815 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
816 start of receiving a non-SMTP message, before any of the message has been
817 read.
818
819 3. When an SMTP error message is specified in a "message" modifier in an ACL,
820 or in a :fail: or :defer: message in a redirect router, Exim now checks the
821 start of the message for an SMTP error code.
822
823 4. There is a new parameter for LDAP lookups called "referrals", which takes
824 one of the settings "follow" (the default) or "nofollow".
825
826 5. Version 20070721.2 of exipick now included, offering these new options:
827 --reverse
828 After all other sorting options have bee processed, reverse order
829 before displaying messages (-R is synonym).
830 --random
831 Randomize order of matching messages before displaying.
832 --size
833 Instead of displaying the matching messages, display the sum
834 of their sizes.
835 --sort <variable>[,<variable>...]
836 Before displaying matching messages, sort the messages according to
837 each messages value for each variable.
838 --not
839 Negate the value for every test (returns inverse output from the
840 same criteria without --not).
841
842
843 Version 4.62
844 ------------
845
846 1. The ${readsocket expansion item now supports Internet domain sockets as well
847 as Unix domain sockets. If the first argument begins "inet:", it must be of
848 the form "inet:host:port". The port is mandatory; it may be a number or the
849 name of a TCP port in /etc/services. The host may be a name, or it may be an
850 IP address. An ip address may optionally be enclosed in square brackets.
851 This is best for IPv6 addresses. For example:
852
853 ${readsocket{inet:[::1]:1234}{<request data>}...
854
855 Only a single host name may be given, but if looking it up yield more than
856 one IP address, they are each tried in turn until a connection is made. Once
857 a connection has been made, the behaviour is as for ${readsocket with a Unix
858 domain socket.
859
860 2. If a redirect router sets up file or pipe deliveries for more than one
861 incoming address, and the relevant transport has batch_max set greater than
862 one, a batch delivery now occurs.
863
864 3. The appendfile transport has a new option called maildirfolder_create_regex.
865 Its value is a regular expression. For a maildir delivery, this is matched
866 against the maildir directory; if it matches, Exim ensures that a
867 maildirfolder file is created alongside the new, cur, and tmp directories.
868
869
870 Version 4.61
871 ------------
872
873 The documentation is up-to-date for the 4.61 release. Major new features since
874 the 4.60 release are:
875
876 . An option called disable_ipv6, to disable the use of IPv6 completely.
877
878 . An increase in the number of ACL variables to 20 of each type.
879
880 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
881 $2, $3, (though those are still set) because the numeric variables get used
882 for other things in complicated expansions.
883
884 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
885
886 . It is possible to use setclassresources() on some BSD OS to control the
887 resources used in pipe deliveries.
888
889 . A new ACL modifier called add_header, which can be used with any verb.
890
891 . More errors are detectable in retry rules.
892
893 There are a number of other additions too.
894
895
896 Version 4.60
897 ------------
898
899 The documentation is up-to-date for the 4.60 release. Major new features since
900 the 4.50 release are:
901
902 . Support for SQLite.
903
904 . Support for IGNOREQUOTA in LMTP.
905
906 . Extensions to the "submission mode" features.
907
908 . Support for Client SMTP Authorization (CSA).
909
910 . Support for ratelimiting hosts and users.
911
912 . New expansion items to help with the BATV "prvs" scheme.
913
914 . A "match_ip" condition, that matches an IP address against a list.
915
916 There are many more minor changes.
917
918 ****