Refactor malware.c and introduce new scanner type "sock". Bugs 1418 and 1396
[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 4.83
10 ------------
11
12 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
13 configured to expect an initial header from a proxy that will make the
14 actual external source IP:host be used in exim instead of the IP of the
15 proxy that is connecting to it.
16
17 2. New verify option header_names_ascii, which will check to make sure
18 there are no non-ASCII characters in header names. Exim itself handles
19 those non-ASCII characters, but downstream apps may not, so Exim can
20 detect and reject if those characters are present.
21
22 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
23 codepoints with valid ones.
24
25 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
26 command line and matching a regex against the return data for trigger
27 and a second regex to extract malware_name. The mail spoofile name can
28 be included in the command line.
29
30
31 Version 4.82
32 ------------
33
34 1. New command-line option -bI:sieve will list all supported sieve extensions
35 of this Exim build on standard output, one per line.
36 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
37 query this to establish the correct list to include in the protocol's
38 SIEVE capability line.
39
40 2. If the -n option is combined with the -bP option, then the name of an
41 emitted option is not output, only the value (if visible to you).
42 For instance, "exim -n -bP pid_file_path" should just emit a pathname
43 followed by a newline, and no other text.
44
45 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
46 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
47 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
48 acceptable for security. (Option accepted but ignored if using OpenSSL).
49 Defaults to 1024, the old value. May be lowered only to 512, or raised as
50 far as you like. Raising this may hinder TLS interoperability with other
51 sites and is not currently recommended. Lowering this will permit you to
52 establish a TLS session which is not as secure as you might like.
53
54 Unless you really know what you are doing, leave it alone.
55
56 4. If not built with DISABLE_DNSSEC, Exim now has the main option
57 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
58 to send the DO flag to your recursive resolver. If you have a recursive
59 resolver, which can set the Authenticated Data (AD) flag in results, Exim
60 can now detect this. Exim does not perform validation itself, instead
61 relying upon a trusted path to the resolver.
62
63 Current status: work-in-progress; $sender_host_dnssec variable added.
64
65 5. DSCP support for outbound connections: on a transport using the smtp driver,
66 set "dscp = ef", for instance, to cause the connections to have the relevant
67 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
68
69 Similarly for inbound connections, there is a new control modifier, dscp,
70 so "warn control = dscp/ef" in the connect ACL, or after authentication.
71
72 Supported values depend upon system libraries. "exim -bI:dscp" to list the
73 ones Exim knows of. You can also set a raw number 0..0x3F.
74
75 6. The -G command-line flag is no longer ignored; it is now equivalent to an
76 ACL setting "control = suppress_local_fixups". The -L command-line flag
77 is now accepted and forces use of syslog, with the provided tag as the
78 process name. A few other flags used by Sendmail are now accepted and
79 ignored.
80
81 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
82 ACL modifier; works for single-recipient mails which are recieved on and
83 deliverable via SMTP. Using the connection made for a recipient verify,
84 if requested before the verify, or a new one made for the purpose while
85 the inbound connection is still active. The bulk of the mail item is copied
86 direct from the inbound socket to the outbound (as well as the spool file).
87 When the source notifies the end of data, the data acceptance by the destination
88 is negociated before the acceptance is sent to the source. If the destination
89 does not accept the mail item, for example due to content-scanning, the item
90 is not accepted from the source and therefore there is no need to generate
91 a bounce mail. This is of benefit when providing a secondary-MX service.
92 The downside is that delays are under the control of the ultimate destination
93 system not your own.
94
95 The Recieved-by: header on items delivered by cutthrough is generated
96 early in reception rather than at the end; this will affect any timestamp
97 included. The log line showing delivery is recorded before that showing
98 reception; it uses a new ">>" tag instead of "=>".
99
100 To support the feature, verify-callout connections can now use ESMTP and TLS.
101 The usual smtp transport options are honoured, plus a (new, default everything)
102 hosts_verify_avoid_tls.
103
104 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
105 for specific access to the information for each connection. The old names
106 are present for now but deprecated.
107
108 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
109
110 8. New expansion operators ${listnamed:name} to get the content of a named list
111 and ${listcount:string} to count the items in a list.
112
113 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
114 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
115 modules. For some situations this is desirable, but we expect admin in
116 those situations to know they want the feature. More commonly, it means
117 that GUI user modules get loaded and are broken by the setuid Exim being
118 unable to access files specified in environment variables and passed
119 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
120 unless this new option is set.
121
122 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
123 so have also added a build option which can be used to build Exim with GnuTLS
124 but without trying to use any kind of PKCS11 support. Uncomment this in the
125 Local/Makefile:
126
127 AVOID_GNUTLS_PKCS11=yes
128
129 10. The "acl = name" condition on an ACL now supports optional arguments.
130 New expansion item "${acl {name}{arg}...}" and expansion condition
131 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
132 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
133 Variable $acl_narg contains the number of arguments. If the ACL sets
134 a "message =" value this becomes the result of the expansion item,
135 or the value of $value for the expansion condition. If the ACL returns
136 accept the expansion condition is true; if reject, false. A defer
137 return results in a forced fail.
138
139 11. Routers and transports can now have multiple headers_add and headers_remove
140 option lines. The concatenated list is used.
141
142 12. New ACL modifier "remove_header" can remove headers before message gets
143 handled by routers/transports.
144
145 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
146 "aaaa" and "a" lookups is done and the full set of results returned.
147
148 14. New expansion variable $headers_added with content from ACL add_header
149 modifier (but not yet added to messsage).
150
151 15. New 8bitmime status logging option for received messages. Log field "M8S".
152
153 16. New authenticated_sender logging option, adding to log field "A".
154
155 17. New expansion variables $router_name and $transport_name. Useful
156 particularly for debug_print as -bt commandline option does not
157 require privilege whereas -d does.
158
159 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
160 proposed extension to SMTP from Eric Hall.
161
162 19. The pipe transport has gained the force_command option, to allow
163 decorating commands from user .forward pipe aliases with prefix
164 wrappers, for instance.
165
166 20. Callout connections can now AUTH; the same controls as normal delivery
167 connections apply.
168
169 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
170 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
171 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
172 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
173 dmarc_status. It adds new control flags dmarc_disable_verify and
174 dmarc_enable_forensic.
175
176 22. Add expansion variable $authenticated_fail_id, which is the username
177 provided to the authentication method which failed. It is available
178 for use in subsequent ACL processing (typically quit or notquit ACLs).
179
180 23. New ACL modifer "udpsend" can construct a UDP packet to send to a given
181 UDP host and port.
182
183 24. New ${hexquote:..string..} expansion operator converts non-printable
184 characters in the string to \xNN form.
185
186 25. Experimental TPDA (Transport Post Delivery Action) function added.
187 Patch provided by Axel Rau.
188
189 26. Experimental Redis lookup added. Patch provided by Warren Baker.
190
191
192 Version 4.80
193 ------------
194
195 1. New authenticator driver, "gsasl". Server-only (at present).
196 This is a SASL interface, licensed under GPL, which can be found at
197 http://www.gnu.org/software/gsasl/.
198 This system does not provide sources of data for authentication, so
199 careful use needs to be made of the conditions in Exim.
200
201 2. New authenticator driver, "heimdal_gssapi". Server-only.
202 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
203 is no longer honoured for setuid programs by Heimdal. Use the
204 "server_keytab" option to point to the keytab.
205
206 3. The "pkg-config" system can now be used when building Exim to reference
207 cflags and library information for lookups and authenticators, rather
208 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
209 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
210 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
211
212 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
213 find the headers and libraries for PCRE.
214
215 4. New expansion variable $tls_bits.
216
217 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
218 be joined together with ASCII NUL characters to construct the key to pass
219 into the DBM library. Can be used with gsasl to access sasldb2 files as
220 used by Cyrus SASL.
221
222 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
223
224 Avoid release 1.0.1a if you can. Note that the default value of
225 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
226 increased susceptibility to attack. This may still have interoperability
227 implications for very old clients (see version 4.31 change 37) but
228 administrators can choose to make the trade-off themselves and restore
229 compatibility at the cost of session security.
230
231 7. Use of the new expansion variable $tls_sni in the main configuration option
232 tls_certificate will cause Exim to re-expand the option, if the client
233 sends the TLS Server Name Indication extension, to permit choosing a
234 different certificate; tls_privatekey will also be re-expanded. You must
235 still set these options to expand to valid files when $tls_sni is not set.
236
237 The SMTP Transport has gained the option tls_sni, which will set a hostname
238 for outbound TLS sessions, and set $tls_sni too.
239
240 A new log_selector, +tls_sni, has been added, to log received SNI values
241 for Exim as a server.
242
243 8. The existing "accept_8bitmime" option now defaults to true. This means
244 that Exim is deliberately not strictly RFC compliant. We're following
245 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
246 Those who disagree, or know that they are talking to mail servers that,
247 even today, are not 8-bit clean, need to turn off this option.
248
249 9. Exim can now be started with -bw (with an optional timeout, given as
250 -bw<timespec>). With this, stdin at startup is a socket that is
251 already listening for connections. This has a more modern name of
252 "socket activation", but forcing the activated socket to fd 0. We're
253 interested in adding more support for modern variants.
254
255 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
256 for numbers indicates multiplication by 1024^3.
257
258 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
259 gnutls_require_mac & gnutls_require_protocols are no longer supported.
260 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
261 string, documentation for which is at:
262 http://www.gnutls.org/manual/html_node/Priority-Strings.html
263
264 SNI support has been added to Exim's GnuTLS integration too.
265
266 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
267 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
268
269 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
270 is now available. If the contents of the file are valid, then Exim will
271 send that back in response to a TLS status request; this is OCSP Stapling.
272 Exim will not maintain the contents of the file in any way: administrators
273 are responsible for ensuring that it is up-to-date.
274
275 See "experimental-spec.txt" for more details.
276
277 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
278 identically to TXT record lookups.
279
280 14. New expansion variable $tod_epoch_l for higher-precision time.
281
282 15. New global option tls_dh_max_bits, defaulting to current value of NSS
283 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
284 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
285
286 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
287 Option can now be a path or an identifier for a standard prime.
288 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
289 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
290 primes.
291
292 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
293 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
294 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
295
296
297 Version 4.77
298 ------------
299
300 1. New options for the ratelimit ACL condition: /count= and /unique=.
301 The /noupdate option has been replaced by a /readonly option.
302
303 2. The SMTP transport's protocol option may now be set to "smtps", to
304 use SSL-on-connect outbound.
305
306 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
307 there is a problem talking to the AV scanner, or the AV scanner running.
308
309 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
310 and check if the search item is a member of the list. This does not
311 support named lists, but does subject the list part to string expansion.
312
313 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
314 built, Exim no longer performs string expansion on the second string of
315 the match_* expansion conditions: "match_address", "match_domain",
316 "match_ip" & "match_local_part". Named lists can still be used.
317
318
319 Version 4.76
320 ------------
321
322 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
323 or off in the resolver library.
324
325
326 Version 4.75
327 ------------
328
329 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
330 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
331 libraries. The following global options have been added in support of
332 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
333 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
334
335 2. The pipe transport now takes a boolean option, "freeze_signal", default
336 false. When true, if the external delivery command exits on a signal then
337 Exim will freeze the message in the queue, instead of generating a bounce.
338
339 3. Log filenames may now use %M as an escape, instead of %D (still available).
340 The %M pattern expands to yyyymm, providing month-level resolution.
341
342 4. The $message_linecount variable is now updated for the maildir_tag option,
343 in the same way as $message_size, to reflect the real number of lines,
344 including any header additions or removals from transport.
345
346 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
347 Exim now selects entries randomly, to better scale in a cluster setup.
348
349
350 Version 4.74
351 ------------
352
353 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
354 the flaw permitted the Exim run-time user to cause root to append to
355 arbitrary files of the attacker's choosing, with the content based
356 on content supplied by the attacker.
357
358 2. Exim now supports loading some lookup types at run-time, using your
359 platform's dlopen() functionality. This has limited platform support
360 and the intention is not to support every variant, it's limited to
361 dlopen(). This permits the main Exim binary to not be linked against
362 all the libraries needed for all the lookup types.
363
364
365 Version 4.73
366 ------------
367
368 NOTE: this version is not guaranteed backwards-compatible, please read the
369 items below carefully
370
371 1. A new main configuration option, "openssl_options", is available if Exim
372 is built with SSL support provided by OpenSSL. The option allows
373 administrators to specify OpenSSL options to be used on connections;
374 typically this is to set bug compatibility features which the OpenSSL
375 developers have not enabled by default. There may be security
376 consequences for certain options, so these should not be changed
377 frivolously.
378
379 2. A new pipe transport option, "permit_coredumps", may help with problem
380 diagnosis in some scenarios. Note that Exim is typically installed as
381 a setuid binary, which on most OSes will inhibit coredumps by default,
382 so that safety mechanism would have to be overridden for this option to
383 be able to take effect.
384
385 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
386 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
387 Note that this switches Exim to use a new API ("INSTREAM") and a future
388 release of ClamAV will remove support for the old API ("STREAM").
389
390 The av_scanner option, when set to "clamd", now takes an optional third
391 part, "local", which causes Exim to pass a filename to ClamAV instead of
392 the file content. This is the same behaviour as when clamd is pointed at
393 a Unix-domain socket. For example:
394
395 av_scanner = clamd:192.0.2.3 1234:local
396
397 ClamAV's ExtendedDetectionInfo response format is now handled.
398
399 4. There is now a -bmalware option, restricted to admin users. This option
400 takes one parameter, a filename, and scans that file with Exim's
401 malware-scanning framework. This is intended purely as a debugging aid
402 to ensure that Exim's scanning is working, not to replace other tools.
403 Note that the ACL framework is not invoked, so if av_scanner references
404 ACL variables without a fallback then this will fail.
405
406 5. There is a new expansion operator, "reverse_ip", which will reverse IP
407 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
408
409 ${reverse_ip:192.0.2.4}
410 -> 4.2.0.192
411 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
412 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
413
414 6. There is a new ACL control called "debug", to enable debug logging.
415 This allows selective logging of certain incoming transactions within
416 production environments, with some care. It takes two options, "tag"
417 and "opts"; "tag" is included in the filename of the log and "opts"
418 is used as per the -d<options> command-line option. Examples, which
419 don't all make sense in all contexts:
420
421 control = debug
422 control = debug/tag=.$sender_host_address
423 control = debug/opts=+expand+acl
424 control = debug/tag=.$message_exim_id/opts=+expand
425
426 7. It has always been implicit in the design and the documentation that
427 "the Exim user" is not root. src/EDITME said that using root was
428 "very strongly discouraged". This is not enough to keep people from
429 shooting themselves in the foot in days when many don't configure Exim
430 themselves but via package build managers. The security consequences of
431 running various bits of network code are severe if there should be bugs in
432 them. As such, the Exim user may no longer be root. If configured
433 statically, Exim will refuse to build. If configured as ref:user then Exim
434 will exit shortly after start-up. If you must shoot yourself in the foot,
435 then henceforth you will have to maintain your own local patches to strip
436 the safeties off.
437
438 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
439 condition logic to determine truth/failure and will fail to expand many
440 strings, bool_lax{} uses the router condition logic, where most strings
441 do evaluate true.
442 Note: bool{00} is false, bool_lax{00} is true.
443
444 9. Routers now support multiple "condition" tests.
445
446 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
447 Setting this allows an admin to define which entry in the tcpwrappers
448 config file will be used to control access to the daemon. This option
449 is only available when Exim is built with USE_TCP_WRAPPERS. The
450 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
451 build option.
452
453 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
454 the Exim run-time user, instead of root.
455
456 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
457 is forced on. This is mitigated by the new build option
458 TRUSTED_CONFIG_LIST which defines a list of configuration files which
459 are trusted; one per line. If a config file is owned by root and matches
460 a pathname in the list, then it may be invoked by the Exim build-time
461 user without Exim relinquishing root privileges.
462
463 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
464 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
465 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
466 include the main config. As a transition mechanism, we are temporarily
467 providing a work-around: the new build option WHITELIST_D_MACROS provides
468 a colon-separated list of macro names which may be overridden by the Exim
469 run-time user. The values of these macros are constrained to the regex
470 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
471
472
473 Version 4.72
474 ------------
475
476 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
477 writable, the other to locking of MBX folders (not mbox).
478
479 2. MySQL stored procedures are now supported.
480
481 3. The dkim_domain transport option is now a list, not a single string, and
482 messages will be signed for each element in the list (discarding
483 duplicates).
484
485 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
486 in the presence of multiple character strings within the RR. Prior to 4.70,
487 only the first string would be returned. The dnsdb lookup now, by default,
488 preserves the pre-4.70 semantics, but also now takes an extended output
489 separator specification. The separator can be followed by a semicolon, to
490 concatenate the individual text strings together with no join character,
491 or by a comma and a second separator character, in which case the text
492 strings within a TXT record are joined on that second character.
493 Administrators are reminded that DNS provides no ordering guarantees
494 between multiple records in an RRset. For example:
495
496 foo.example. IN TXT "a" "b" "c"
497 foo.example. IN TXT "d" "e" "f"
498
499 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
500 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
501 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
502
503
504 Version 4.70 / 4.71
505 -------------------
506
507 1. Native DKIM support without an external library.
508 (Note that if no action to prevent it is taken, a straight upgrade will
509 result in DKIM verification of all signed incoming emails. See spec
510 for details on conditionally disabling)
511
512 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
513
514 3. There is now a bool{} expansion condition which maps certain strings to
515 true/false condition values (most likely of use in conjunction with the
516 and{} expansion operator).
517
518 4. The $spam_score, $spam_bar and $spam_report variables are now available
519 at delivery time.
520
521 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
522 options, provided that Exim is invoked by an admin_user.
523
524 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
525 which increases compatibility with older clients at the cost of decreased
526 security. Don't set this unless you need to support such clients.
527
528 7. There is a new expansion operator, ${randint:...} which will produce a
529 "random" number less than the supplied integer. This randomness is
530 not guaranteed to be cryptographically strong, but depending upon how
531 Exim was built may be better than the most naive schemes.
532
533 8. Exim now explicitly ensures that SHA256 is available when linked against
534 OpenSSL.
535
536 9. The transport_filter_timeout option now applies to SMTP transports too.
537
538
539 Version 4.69
540 ------------
541
542 1. Preliminary DKIM support in Experimental.
543
544
545 Version 4.68
546 ------------
547
548 1. The body_linecount and body_zerocount C variables are now exported in the
549 local_scan API.
550
551 2. When a dnslists lookup succeeds, the key that was looked up is now placed
552 in $dnslist_matched. When the key is an IP address, it is not reversed in
553 this variable (though it is, of course, in the actual lookup). In simple
554 cases, for example:
555
556 deny dnslists = spamhaus.example
557
558 the key is also available in another variable (in this case,
559 $sender_host_address). In more complicated cases, however, this is not
560 true. For example, using a data lookup might generate a dnslists lookup
561 like this:
562
563 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
564
565 If this condition succeeds, the value in $dnslist_matched might be
566 192.168.6.7 (for example).
567
568 3. Authenticators now have a client_condition option. When Exim is running as
569 a client, it skips an authenticator whose client_condition expansion yields
570 "0", "no", or "false". This can be used, for example, to skip plain text
571 authenticators when the connection is not encrypted by a setting such as:
572
573 client_condition = ${if !eq{$tls_cipher}{}}
574
575 Note that the 4.67 documentation states that $tls_cipher contains the
576 cipher used for incoming messages. In fact, during SMTP delivery, it
577 contains the cipher used for the delivery. The same is true for
578 $tls_peerdn.
579
580 4. There is now a -Mvc <message-id> option, which outputs a copy of the
581 message to the standard output, in RFC 2822 format. The option can be used
582 only by an admin user.
583
584 5. There is now a /noupdate option for the ratelimit ACL condition. It
585 computes the rate and checks the limit as normal, but it does not update
586 the saved data. This means that, in relevant ACLs, it is possible to lookup
587 the existence of a specified (or auto-generated) ratelimit key without
588 incrementing the ratelimit counter for that key.
589
590 In order for this to be useful, another ACL entry must set the rate
591 for the same key somewhere (otherwise it will always be zero).
592
593 Example:
594
595 acl_check_connect:
596 # Read the rate; if it doesn't exist or is below the maximum
597 # we update it below
598 deny ratelimit = 100 / 5m / strict / noupdate
599 log_message = RATE: $sender_rate / $sender_rate_period \
600 (max $sender_rate_limit)
601
602 [... some other logic and tests...]
603
604 warn ratelimit = 100 / 5m / strict / per_cmd
605 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
606 (max $sender_rate_limit)
607 condition = ${if le{$sender_rate}{$sender_rate_limit}}
608
609 accept
610
611 6. The variable $max_received_linelength contains the number of bytes in the
612 longest line that was received as part of the message, not counting the
613 line termination character(s).
614
615 7. Host lists can now include +ignore_defer and +include_defer, analagous to
616 +ignore_unknown and +include_unknown. These options should be used with
617 care, probably only in non-critical host lists such as whitelists.
618
619 8. There's a new option called queue_only_load_latch, which defaults true.
620 If set false when queue_only_load is greater than zero, Exim re-evaluates
621 the load for each incoming message in an SMTP session. Otherwise, once one
622 message is queued, the remainder are also.
623
624 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
625 cases when an SMTP session ends without sending QUIT. However, when Exim
626 itself is is bad trouble, such as being unable to write to its log files,
627 this ACL is not run, because it might try to do things (such as write to
628 log files) that make the situation even worse.
629
630 Like the QUIT ACL, this new ACL is provided to make it possible to gather
631 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
632 modifier is forbidden in this ACL.
633
634 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
635 to a string that indicates the reason for the termination of the SMTP
636 connection. The possible values are:
637
638 acl-drop Another ACL issued a "drop" command
639 bad-commands Too many unknown or non-mail commands
640 command-timeout Timeout while reading SMTP commands
641 connection-lost The SMTP connection has been lost
642 data-timeout Timeout while reading message data
643 local-scan-error The local_scan() function crashed
644 local-scan-timeout The local_scan() function timed out
645 signal-exit SIGTERM or SIGINT
646 synchronization-error SMTP synchronization error
647 tls-failed TLS failed to start
648
649 In most cases when an SMTP connection is closed without having received
650 QUIT, Exim sends an SMTP response message before actually closing the
651 connection. With the exception of acl-drop, the default message can be
652 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
653 "drop" verb in another ACL, it is the message from the other ACL that is
654 used.
655
656 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
657 servers with individual queries. This is done by starting the query with
658 "servers=x:y:z;", where each item in the list may take one of two forms:
659
660 (1) If it is just a host name, the appropriate global option (mysql_servers
661 or pgsql_servers) is searched for a host of the same name, and the
662 remaining parameters (database, user, password) are taken from there.
663
664 (2) If it contains any slashes, it is taken as a complete parameter set.
665
666 The list of servers is used in exactly the same was as the global list.
667 Once a connection to a server has happened and a query has been
668 successfully executed, processing of the lookup ceases.
669
670 This feature is intended for use in master/slave situations where updates
671 are occurring, and one wants to update a master rather than a slave. If the
672 masters are in the list for reading, you might have:
673
674 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
675
676 In an updating lookup, you could then write
677
678 ${lookup mysql{servers=master; UPDATE ...}
679
680 If, on the other hand, the master is not to be used for reading lookups:
681
682 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
683
684 you can still update the master by
685
686 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
687
688 11. The message_body_newlines option (default FALSE, for backwards
689 compatibility) can be used to control whether newlines are present in
690 $message_body and $message_body_end. If it is FALSE, they are replaced by
691 spaces.
692
693
694 Version 4.67
695 ------------
696
697 1. There is a new log selector called smtp_no_mail, which is not included in
698 the default setting. When it is set, a line is written to the main log
699 whenever an accepted SMTP connection terminates without having issued a
700 MAIL command.
701
702 2. When an item in a dnslists list is followed by = and & and a list of IP
703 addresses, the behaviour was not clear when the lookup returned more than
704 one IP address. This has been solved by the addition of == and =& for "all"
705 rather than the default "any" matching.
706
707 3. Up till now, the only control over which cipher suites GnuTLS uses has been
708 for the cipher algorithms. New options have been added to allow some of the
709 other parameters to be varied.
710
711 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
712 set, Exim compiles a runtime option called disable_fsync.
713
714 5. There is a new variable called $smtp_count_at_connection_start.
715
716 6. There's a new control called no_pipelining.
717
718 7. There are two new variables called $sending_ip_address and $sending_port.
719 These are set whenever an SMTP connection to another host has been set up.
720
721 8. The expansion of the helo_data option in the smtp transport now happens
722 after the connection to the server has been made.
723
724 9. There is a new expansion operator ${rfc2047d: that decodes strings that
725 are encoded as per RFC 2047.
726
727 10. There is a new log selector called "pid", which causes the current process
728 id to be added to every log line, in square brackets, immediately after the
729 time and date.
730
731 11. Exim has been modified so that it flushes SMTP output before implementing
732 a delay in an ACL. It also flushes the output before performing a callout,
733 as this can take a substantial time. These behaviours can be disabled by
734 obeying control = no_delay_flush or control = no_callout_flush,
735 respectively, at some earlier stage of the connection.
736
737 12. There are two new expansion conditions that iterate over a list. They are
738 called forany and forall.
739
740 13. There's a new global option called dsn_from that can be used to vary the
741 contents of From: lines in bounces and other automatically generated
742 messages ("delivery status notifications" - hence the name of the option).
743
744 14. The smtp transport has a new option called hosts_avoid_pipelining.
745
746 15. By default, exigrep does case-insensitive matches. There is now a -I option
747 that makes it case-sensitive.
748
749 16. A number of new features ("addresses", "map", "filter", and "reduce") have
750 been added to string expansions to make it easier to process lists of
751 items, typically addresses.
752
753 17. There's a new ACL modifier called "continue". It does nothing of itself,
754 and processing of the ACL always continues with the next condition or
755 modifier. It is provided so that the side effects of expanding its argument
756 can be used.
757
758 18. It is now possible to use newline and other control characters (those with
759 values less than 32, plus DEL) as separators in lists.
760
761 19. The exigrep utility now has a -v option, which inverts the matching
762 condition.
763
764 20. The host_find_failed option in the manualroute router can now be set to
765 "ignore".
766
767
768 Version 4.66
769 ------------
770
771 No new features were added to 4.66.
772
773
774 Version 4.65
775 ------------
776
777 No new features were added to 4.65.
778
779
780 Version 4.64
781 ------------
782
783 1. ACL variables can now be given arbitrary names, as long as they start with
784 "acl_c" or "acl_m" (for connection variables and message variables), are at
785 least six characters long, with the sixth character being either a digit or
786 an underscore.
787
788 2. There is a new ACL modifier called log_reject_target. It makes it possible
789 to specify which logs are used for messages about ACL rejections.
790
791 3. There is a new authenticator called "dovecot". This is an interface to the
792 authentication facility of the Dovecot POP/IMAP server, which can support a
793 number of authentication methods.
794
795 4. The variable $message_headers_raw provides a concatenation of all the
796 messages's headers without any decoding. This is in contrast to
797 $message_headers, which does RFC2047 decoding on the header contents.
798
799 5. In a DNS black list, if two domain names, comma-separated, are given, the
800 second is used first to do an initial check, making use of any IP value
801 restrictions that are set. If there is a match, the first domain is used,
802 without any IP value restrictions, to get the TXT record.
803
804 6. All authenticators now have a server_condition option.
805
806 7. There is a new command-line option called -Mset. It is useful only in
807 conjunction with -be (that is, when testing string expansions). It must be
808 followed by a message id; Exim loads the given message from its spool
809 before doing the expansions.
810
811 8. Another similar new command-line option is called -bem. It operates like
812 -be except that it must be followed by the name of a file that contains a
813 message.
814
815 9. When an address is delayed because of a 4xx response to a RCPT command, it
816 is now the combination of sender and recipient that is delayed in
817 subsequent queue runs until its retry time is reached.
818
819 10. Unary negation and the bitwise logical operators and, or, xor, not, and
820 shift, have been added to the eval: and eval10: expansion items.
821
822 11. The variables $interface_address and $interface_port have been renamed
823 as $received_ip_address and $received_port, to make it clear that they
824 relate to message reception rather than delivery. (The old names remain
825 available for compatibility.)
826
827 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
828 to vary the message that is sent when an SMTP command is accepted.
829
830
831 Version 4.63
832 ------------
833
834 1. There is a new Boolean option called filter_prepend_home for the redirect
835 router.
836
837 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
838 start of receiving a non-SMTP message, before any of the message has been
839 read.
840
841 3. When an SMTP error message is specified in a "message" modifier in an ACL,
842 or in a :fail: or :defer: message in a redirect router, Exim now checks the
843 start of the message for an SMTP error code.
844
845 4. There is a new parameter for LDAP lookups called "referrals", which takes
846 one of the settings "follow" (the default) or "nofollow".
847
848 5. Version 20070721.2 of exipick now included, offering these new options:
849 --reverse
850 After all other sorting options have bee processed, reverse order
851 before displaying messages (-R is synonym).
852 --random
853 Randomize order of matching messages before displaying.
854 --size
855 Instead of displaying the matching messages, display the sum
856 of their sizes.
857 --sort <variable>[,<variable>...]
858 Before displaying matching messages, sort the messages according to
859 each messages value for each variable.
860 --not
861 Negate the value for every test (returns inverse output from the
862 same criteria without --not).
863
864
865 Version 4.62
866 ------------
867
868 1. The ${readsocket expansion item now supports Internet domain sockets as well
869 as Unix domain sockets. If the first argument begins "inet:", it must be of
870 the form "inet:host:port". The port is mandatory; it may be a number or the
871 name of a TCP port in /etc/services. The host may be a name, or it may be an
872 IP address. An ip address may optionally be enclosed in square brackets.
873 This is best for IPv6 addresses. For example:
874
875 ${readsocket{inet:[::1]:1234}{<request data>}...
876
877 Only a single host name may be given, but if looking it up yield more than
878 one IP address, they are each tried in turn until a connection is made. Once
879 a connection has been made, the behaviour is as for ${readsocket with a Unix
880 domain socket.
881
882 2. If a redirect router sets up file or pipe deliveries for more than one
883 incoming address, and the relevant transport has batch_max set greater than
884 one, a batch delivery now occurs.
885
886 3. The appendfile transport has a new option called maildirfolder_create_regex.
887 Its value is a regular expression. For a maildir delivery, this is matched
888 against the maildir directory; if it matches, Exim ensures that a
889 maildirfolder file is created alongside the new, cur, and tmp directories.
890
891
892 Version 4.61
893 ------------
894
895 The documentation is up-to-date for the 4.61 release. Major new features since
896 the 4.60 release are:
897
898 . An option called disable_ipv6, to disable the use of IPv6 completely.
899
900 . An increase in the number of ACL variables to 20 of each type.
901
902 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
903 $2, $3, (though those are still set) because the numeric variables get used
904 for other things in complicated expansions.
905
906 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
907
908 . It is possible to use setclassresources() on some BSD OS to control the
909 resources used in pipe deliveries.
910
911 . A new ACL modifier called add_header, which can be used with any verb.
912
913 . More errors are detectable in retry rules.
914
915 There are a number of other additions too.
916
917
918 Version 4.60
919 ------------
920
921 The documentation is up-to-date for the 4.60 release. Major new features since
922 the 4.50 release are:
923
924 . Support for SQLite.
925
926 . Support for IGNOREQUOTA in LMTP.
927
928 . Extensions to the "submission mode" features.
929
930 . Support for Client SMTP Authorization (CSA).
931
932 . Support for ratelimiting hosts and users.
933
934 . New expansion items to help with the BATV "prvs" scheme.
935
936 . A "match_ip" condition, that matches an IP address against a list.
937
938 There are many more minor changes.
939
940 ****