Add support for avast malware scanner. Bug 1033
[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 4.86
10 ------------
11
12 1. Support for using the system standard CA bundle.
13
14 2. New expansion items $config_file, $config_dir, containing the file
15 and directory name of the main configuration file. Also $exim_version.
16
17 3. New "malware=" support for Avast.
18
19 Version 4.85
20 ------------
21
22 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
23 DANE smtp draft to assess a secure chain of trust of the certificate
24 used to establish the TLS connection based on a TLSA record in the
25 domain of the sender.
26
27 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
28 and several new events have been created. The reason is because it has
29 been expanded beyond just firing events during the transport phase. Any
30 existing TPDA transport options will have to be rewritten to use a new
31 $event_name expansion variable in a condition. Refer to the
32 experimental-spec.txt for details and examples.
33
34 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
35 server certs used for TLS match the result of the MX lookup. It does
36 not use the same mechanism as DANE.
37
38
39 Version 4.84
40 ------------
41
42
43 Version 4.83
44 ------------
45
46 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
47 configured to expect an initial header from a proxy that will make the
48 actual external source IP:host be used in exim instead of the IP of the
49 proxy that is connecting to it.
50
51 2. New verify option header_names_ascii, which will check to make sure
52 there are no non-ASCII characters in header names. Exim itself handles
53 those non-ASCII characters, but downstream apps may not, so Exim can
54 detect and reject if those characters are present.
55
56 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
57 codepoints with valid ones.
58
59 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
60 command line and matching a regex against the return data for trigger
61 and a second regex to extract malware_name. The mail spoolfile name can
62 be included in the command line.
63
64 5. The smtp transport now supports options "tls_verify_hosts" and
65 "tls_try_verify_hosts". If either is set the certificate verification
66 is split from the encryption operation. The default remains that a failed
67 verification cancels the encryption.
68
69 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
70 lookup can now set a list of servers to use that is different from the
71 default list.
72
73 7. New command-line option -C for exiqgrep to specify alternate exim.conf
74 file when searching the queue.
75
76 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
77
78 9. Support for DNSSEC on outbound connections.
79
80 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
81 "certextract" to extract fields from them. Hash operators md5 and sha1
82 work over them for generating fingerprints, and a new sha256 operator
83 for them added.
84
85 11. PRDR is now supported dy default.
86
87 12. OCSP stapling is now supported by default.
88
89 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
90 Delivery Status Notification messages in MIME format, and negociate
91 DSN features per RFC 3461.
92
93
94 Version 4.82
95 ------------
96
97 1. New command-line option -bI:sieve will list all supported sieve extensions
98 of this Exim build on standard output, one per line.
99 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
100 query this to establish the correct list to include in the protocol's
101 SIEVE capability line.
102
103 2. If the -n option is combined with the -bP option, then the name of an
104 emitted option is not output, only the value (if visible to you).
105 For instance, "exim -n -bP pid_file_path" should just emit a pathname
106 followed by a newline, and no other text.
107
108 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
109 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
110 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
111 acceptable for security. (Option accepted but ignored if using OpenSSL).
112 Defaults to 1024, the old value. May be lowered only to 512, or raised as
113 far as you like. Raising this may hinder TLS interoperability with other
114 sites and is not currently recommended. Lowering this will permit you to
115 establish a TLS session which is not as secure as you might like.
116
117 Unless you really know what you are doing, leave it alone.
118
119 4. If not built with DISABLE_DNSSEC, Exim now has the main option
120 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
121 to send the DO flag to your recursive resolver. If you have a recursive
122 resolver, which can set the Authenticated Data (AD) flag in results, Exim
123 can now detect this. Exim does not perform validation itself, instead
124 relying upon a trusted path to the resolver.
125
126 Current status: work-in-progress; $sender_host_dnssec variable added.
127
128 5. DSCP support for outbound connections: on a transport using the smtp driver,
129 set "dscp = ef", for instance, to cause the connections to have the relevant
130 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
131
132 Similarly for inbound connections, there is a new control modifier, dscp,
133 so "warn control = dscp/ef" in the connect ACL, or after authentication.
134
135 Supported values depend upon system libraries. "exim -bI:dscp" to list the
136 ones Exim knows of. You can also set a raw number 0..0x3F.
137
138 6. The -G command-line flag is no longer ignored; it is now equivalent to an
139 ACL setting "control = suppress_local_fixups". The -L command-line flag
140 is now accepted and forces use of syslog, with the provided tag as the
141 process name. A few other flags used by Sendmail are now accepted and
142 ignored.
143
144 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
145 ACL modifier; works for single-recipient mails which are recieved on and
146 deliverable via SMTP. Using the connection made for a recipient verify,
147 if requested before the verify, or a new one made for the purpose while
148 the inbound connection is still active. The bulk of the mail item is copied
149 direct from the inbound socket to the outbound (as well as the spool file).
150 When the source notifies the end of data, the data acceptance by the destination
151 is negociated before the acceptance is sent to the source. If the destination
152 does not accept the mail item, for example due to content-scanning, the item
153 is not accepted from the source and therefore there is no need to generate
154 a bounce mail. This is of benefit when providing a secondary-MX service.
155 The downside is that delays are under the control of the ultimate destination
156 system not your own.
157
158 The Recieved-by: header on items delivered by cutthrough is generated
159 early in reception rather than at the end; this will affect any timestamp
160 included. The log line showing delivery is recorded before that showing
161 reception; it uses a new ">>" tag instead of "=>".
162
163 To support the feature, verify-callout connections can now use ESMTP and TLS.
164 The usual smtp transport options are honoured, plus a (new, default everything)
165 hosts_verify_avoid_tls.
166
167 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
168 for specific access to the information for each connection. The old names
169 are present for now but deprecated.
170
171 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
172
173 8. New expansion operators ${listnamed:name} to get the content of a named list
174 and ${listcount:string} to count the items in a list.
175
176 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
177 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
178 modules. For some situations this is desirable, but we expect admin in
179 those situations to know they want the feature. More commonly, it means
180 that GUI user modules get loaded and are broken by the setuid Exim being
181 unable to access files specified in environment variables and passed
182 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
183 unless this new option is set.
184
185 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
186 so have also added a build option which can be used to build Exim with GnuTLS
187 but without trying to use any kind of PKCS11 support. Uncomment this in the
188 Local/Makefile:
189
190 AVOID_GNUTLS_PKCS11=yes
191
192 10. The "acl = name" condition on an ACL now supports optional arguments.
193 New expansion item "${acl {name}{arg}...}" and expansion condition
194 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
195 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
196 Variable $acl_narg contains the number of arguments. If the ACL sets
197 a "message =" value this becomes the result of the expansion item,
198 or the value of $value for the expansion condition. If the ACL returns
199 accept the expansion condition is true; if reject, false. A defer
200 return results in a forced fail.
201
202 11. Routers and transports can now have multiple headers_add and headers_remove
203 option lines. The concatenated list is used.
204
205 12. New ACL modifier "remove_header" can remove headers before message gets
206 handled by routers/transports.
207
208 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
209 "aaaa" and "a" lookups is done and the full set of results returned.
210
211 14. New expansion variable $headers_added with content from ACL add_header
212 modifier (but not yet added to messsage).
213
214 15. New 8bitmime status logging option for received messages. Log field "M8S".
215
216 16. New authenticated_sender logging option, adding to log field "A".
217
218 17. New expansion variables $router_name and $transport_name. Useful
219 particularly for debug_print as -bt commandline option does not
220 require privilege whereas -d does.
221
222 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
223 proposed extension to SMTP from Eric Hall.
224
225 19. The pipe transport has gained the force_command option, to allow
226 decorating commands from user .forward pipe aliases with prefix
227 wrappers, for instance.
228
229 20. Callout connections can now AUTH; the same controls as normal delivery
230 connections apply.
231
232 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
233 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
234 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
235 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
236 dmarc_status. It adds new control flags dmarc_disable_verify and
237 dmarc_enable_forensic.
238
239 22. Add expansion variable $authenticated_fail_id, which is the username
240 provided to the authentication method which failed. It is available
241 for use in subsequent ACL processing (typically quit or notquit ACLs).
242
243 23. New ACL modifer "udpsend" can construct a UDP packet to send to a given
244 UDP host and port.
245
246 24. New ${hexquote:..string..} expansion operator converts non-printable
247 characters in the string to \xNN form.
248
249 25. Experimental TPDA (Transport Post Delivery Action) function added.
250 Patch provided by Axel Rau.
251
252 26. Experimental Redis lookup added. Patch provided by Warren Baker.
253
254
255 Version 4.80
256 ------------
257
258 1. New authenticator driver, "gsasl". Server-only (at present).
259 This is a SASL interface, licensed under GPL, which can be found at
260 http://www.gnu.org/software/gsasl/.
261 This system does not provide sources of data for authentication, so
262 careful use needs to be made of the conditions in Exim.
263
264 2. New authenticator driver, "heimdal_gssapi". Server-only.
265 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
266 is no longer honoured for setuid programs by Heimdal. Use the
267 "server_keytab" option to point to the keytab.
268
269 3. The "pkg-config" system can now be used when building Exim to reference
270 cflags and library information for lookups and authenticators, rather
271 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
272 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
273 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
274
275 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
276 find the headers and libraries for PCRE.
277
278 4. New expansion variable $tls_bits.
279
280 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
281 be joined together with ASCII NUL characters to construct the key to pass
282 into the DBM library. Can be used with gsasl to access sasldb2 files as
283 used by Cyrus SASL.
284
285 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
286
287 Avoid release 1.0.1a if you can. Note that the default value of
288 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
289 increased susceptibility to attack. This may still have interoperability
290 implications for very old clients (see version 4.31 change 37) but
291 administrators can choose to make the trade-off themselves and restore
292 compatibility at the cost of session security.
293
294 7. Use of the new expansion variable $tls_sni in the main configuration option
295 tls_certificate will cause Exim to re-expand the option, if the client
296 sends the TLS Server Name Indication extension, to permit choosing a
297 different certificate; tls_privatekey will also be re-expanded. You must
298 still set these options to expand to valid files when $tls_sni is not set.
299
300 The SMTP Transport has gained the option tls_sni, which will set a hostname
301 for outbound TLS sessions, and set $tls_sni too.
302
303 A new log_selector, +tls_sni, has been added, to log received SNI values
304 for Exim as a server.
305
306 8. The existing "accept_8bitmime" option now defaults to true. This means
307 that Exim is deliberately not strictly RFC compliant. We're following
308 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
309 Those who disagree, or know that they are talking to mail servers that,
310 even today, are not 8-bit clean, need to turn off this option.
311
312 9. Exim can now be started with -bw (with an optional timeout, given as
313 -bw<timespec>). With this, stdin at startup is a socket that is
314 already listening for connections. This has a more modern name of
315 "socket activation", but forcing the activated socket to fd 0. We're
316 interested in adding more support for modern variants.
317
318 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
319 for numbers indicates multiplication by 1024^3.
320
321 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
322 gnutls_require_mac & gnutls_require_protocols are no longer supported.
323 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
324 string, documentation for which is at:
325 http://www.gnutls.org/manual/html_node/Priority-Strings.html
326
327 SNI support has been added to Exim's GnuTLS integration too.
328
329 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
330 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
331
332 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
333 is now available. If the contents of the file are valid, then Exim will
334 send that back in response to a TLS status request; this is OCSP Stapling.
335 Exim will not maintain the contents of the file in any way: administrators
336 are responsible for ensuring that it is up-to-date.
337
338 See "experimental-spec.txt" for more details.
339
340 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
341 identically to TXT record lookups.
342
343 14. New expansion variable $tod_epoch_l for higher-precision time.
344
345 15. New global option tls_dh_max_bits, defaulting to current value of NSS
346 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
347 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
348
349 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
350 Option can now be a path or an identifier for a standard prime.
351 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
352 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
353 primes.
354
355 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
356 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
357 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
358
359
360 Version 4.77
361 ------------
362
363 1. New options for the ratelimit ACL condition: /count= and /unique=.
364 The /noupdate option has been replaced by a /readonly option.
365
366 2. The SMTP transport's protocol option may now be set to "smtps", to
367 use SSL-on-connect outbound.
368
369 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
370 there is a problem talking to the AV scanner, or the AV scanner running.
371
372 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
373 and check if the search item is a member of the list. This does not
374 support named lists, but does subject the list part to string expansion.
375
376 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
377 built, Exim no longer performs string expansion on the second string of
378 the match_* expansion conditions: "match_address", "match_domain",
379 "match_ip" & "match_local_part". Named lists can still be used.
380
381
382 Version 4.76
383 ------------
384
385 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
386 or off in the resolver library.
387
388
389 Version 4.75
390 ------------
391
392 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
393 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
394 libraries. The following global options have been added in support of
395 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
396 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
397
398 2. The pipe transport now takes a boolean option, "freeze_signal", default
399 false. When true, if the external delivery command exits on a signal then
400 Exim will freeze the message in the queue, instead of generating a bounce.
401
402 3. Log filenames may now use %M as an escape, instead of %D (still available).
403 The %M pattern expands to yyyymm, providing month-level resolution.
404
405 4. The $message_linecount variable is now updated for the maildir_tag option,
406 in the same way as $message_size, to reflect the real number of lines,
407 including any header additions or removals from transport.
408
409 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
410 Exim now selects entries randomly, to better scale in a cluster setup.
411
412
413 Version 4.74
414 ------------
415
416 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
417 the flaw permitted the Exim run-time user to cause root to append to
418 arbitrary files of the attacker's choosing, with the content based
419 on content supplied by the attacker.
420
421 2. Exim now supports loading some lookup types at run-time, using your
422 platform's dlopen() functionality. This has limited platform support
423 and the intention is not to support every variant, it's limited to
424 dlopen(). This permits the main Exim binary to not be linked against
425 all the libraries needed for all the lookup types.
426
427
428 Version 4.73
429 ------------
430
431 NOTE: this version is not guaranteed backwards-compatible, please read the
432 items below carefully
433
434 1. A new main configuration option, "openssl_options", is available if Exim
435 is built with SSL support provided by OpenSSL. The option allows
436 administrators to specify OpenSSL options to be used on connections;
437 typically this is to set bug compatibility features which the OpenSSL
438 developers have not enabled by default. There may be security
439 consequences for certain options, so these should not be changed
440 frivolously.
441
442 2. A new pipe transport option, "permit_coredumps", may help with problem
443 diagnosis in some scenarios. Note that Exim is typically installed as
444 a setuid binary, which on most OSes will inhibit coredumps by default,
445 so that safety mechanism would have to be overridden for this option to
446 be able to take effect.
447
448 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
449 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
450 Note that this switches Exim to use a new API ("INSTREAM") and a future
451 release of ClamAV will remove support for the old API ("STREAM").
452
453 The av_scanner option, when set to "clamd", now takes an optional third
454 part, "local", which causes Exim to pass a filename to ClamAV instead of
455 the file content. This is the same behaviour as when clamd is pointed at
456 a Unix-domain socket. For example:
457
458 av_scanner = clamd:192.0.2.3 1234:local
459
460 ClamAV's ExtendedDetectionInfo response format is now handled.
461
462 4. There is now a -bmalware option, restricted to admin users. This option
463 takes one parameter, a filename, and scans that file with Exim's
464 malware-scanning framework. This is intended purely as a debugging aid
465 to ensure that Exim's scanning is working, not to replace other tools.
466 Note that the ACL framework is not invoked, so if av_scanner references
467 ACL variables without a fallback then this will fail.
468
469 5. There is a new expansion operator, "reverse_ip", which will reverse IP
470 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
471
472 ${reverse_ip:192.0.2.4}
473 -> 4.2.0.192
474 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
475 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
476
477 6. There is a new ACL control called "debug", to enable debug logging.
478 This allows selective logging of certain incoming transactions within
479 production environments, with some care. It takes two options, "tag"
480 and "opts"; "tag" is included in the filename of the log and "opts"
481 is used as per the -d<options> command-line option. Examples, which
482 don't all make sense in all contexts:
483
484 control = debug
485 control = debug/tag=.$sender_host_address
486 control = debug/opts=+expand+acl
487 control = debug/tag=.$message_exim_id/opts=+expand
488
489 7. It has always been implicit in the design and the documentation that
490 "the Exim user" is not root. src/EDITME said that using root was
491 "very strongly discouraged". This is not enough to keep people from
492 shooting themselves in the foot in days when many don't configure Exim
493 themselves but via package build managers. The security consequences of
494 running various bits of network code are severe if there should be bugs in
495 them. As such, the Exim user may no longer be root. If configured
496 statically, Exim will refuse to build. If configured as ref:user then Exim
497 will exit shortly after start-up. If you must shoot yourself in the foot,
498 then henceforth you will have to maintain your own local patches to strip
499 the safeties off.
500
501 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
502 condition logic to determine truth/failure and will fail to expand many
503 strings, bool_lax{} uses the router condition logic, where most strings
504 do evaluate true.
505 Note: bool{00} is false, bool_lax{00} is true.
506
507 9. Routers now support multiple "condition" tests.
508
509 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
510 Setting this allows an admin to define which entry in the tcpwrappers
511 config file will be used to control access to the daemon. This option
512 is only available when Exim is built with USE_TCP_WRAPPERS. The
513 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
514 build option.
515
516 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
517 the Exim run-time user, instead of root.
518
519 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
520 is forced on. This is mitigated by the new build option
521 TRUSTED_CONFIG_LIST which defines a list of configuration files which
522 are trusted; one per line. If a config file is owned by root and matches
523 a pathname in the list, then it may be invoked by the Exim build-time
524 user without Exim relinquishing root privileges.
525
526 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
527 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
528 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
529 include the main config. As a transition mechanism, we are temporarily
530 providing a work-around: the new build option WHITELIST_D_MACROS provides
531 a colon-separated list of macro names which may be overridden by the Exim
532 run-time user. The values of these macros are constrained to the regex
533 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
534
535
536 Version 4.72
537 ------------
538
539 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
540 writable, the other to locking of MBX folders (not mbox).
541
542 2. MySQL stored procedures are now supported.
543
544 3. The dkim_domain transport option is now a list, not a single string, and
545 messages will be signed for each element in the list (discarding
546 duplicates).
547
548 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
549 in the presence of multiple character strings within the RR. Prior to 4.70,
550 only the first string would be returned. The dnsdb lookup now, by default,
551 preserves the pre-4.70 semantics, but also now takes an extended output
552 separator specification. The separator can be followed by a semicolon, to
553 concatenate the individual text strings together with no join character,
554 or by a comma and a second separator character, in which case the text
555 strings within a TXT record are joined on that second character.
556 Administrators are reminded that DNS provides no ordering guarantees
557 between multiple records in an RRset. For example:
558
559 foo.example. IN TXT "a" "b" "c"
560 foo.example. IN TXT "d" "e" "f"
561
562 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
563 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
564 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
565
566
567 Version 4.70 / 4.71
568 -------------------
569
570 1. Native DKIM support without an external library.
571 (Note that if no action to prevent it is taken, a straight upgrade will
572 result in DKIM verification of all signed incoming emails. See spec
573 for details on conditionally disabling)
574
575 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
576
577 3. There is now a bool{} expansion condition which maps certain strings to
578 true/false condition values (most likely of use in conjunction with the
579 and{} expansion operator).
580
581 4. The $spam_score, $spam_bar and $spam_report variables are now available
582 at delivery time.
583
584 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
585 options, provided that Exim is invoked by an admin_user.
586
587 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
588 which increases compatibility with older clients at the cost of decreased
589 security. Don't set this unless you need to support such clients.
590
591 7. There is a new expansion operator, ${randint:...} which will produce a
592 "random" number less than the supplied integer. This randomness is
593 not guaranteed to be cryptographically strong, but depending upon how
594 Exim was built may be better than the most naive schemes.
595
596 8. Exim now explicitly ensures that SHA256 is available when linked against
597 OpenSSL.
598
599 9. The transport_filter_timeout option now applies to SMTP transports too.
600
601
602 Version 4.69
603 ------------
604
605 1. Preliminary DKIM support in Experimental.
606
607
608 Version 4.68
609 ------------
610
611 1. The body_linecount and body_zerocount C variables are now exported in the
612 local_scan API.
613
614 2. When a dnslists lookup succeeds, the key that was looked up is now placed
615 in $dnslist_matched. When the key is an IP address, it is not reversed in
616 this variable (though it is, of course, in the actual lookup). In simple
617 cases, for example:
618
619 deny dnslists = spamhaus.example
620
621 the key is also available in another variable (in this case,
622 $sender_host_address). In more complicated cases, however, this is not
623 true. For example, using a data lookup might generate a dnslists lookup
624 like this:
625
626 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
627
628 If this condition succeeds, the value in $dnslist_matched might be
629 192.168.6.7 (for example).
630
631 3. Authenticators now have a client_condition option. When Exim is running as
632 a client, it skips an authenticator whose client_condition expansion yields
633 "0", "no", or "false". This can be used, for example, to skip plain text
634 authenticators when the connection is not encrypted by a setting such as:
635
636 client_condition = ${if !eq{$tls_cipher}{}}
637
638 Note that the 4.67 documentation states that $tls_cipher contains the
639 cipher used for incoming messages. In fact, during SMTP delivery, it
640 contains the cipher used for the delivery. The same is true for
641 $tls_peerdn.
642
643 4. There is now a -Mvc <message-id> option, which outputs a copy of the
644 message to the standard output, in RFC 2822 format. The option can be used
645 only by an admin user.
646
647 5. There is now a /noupdate option for the ratelimit ACL condition. It
648 computes the rate and checks the limit as normal, but it does not update
649 the saved data. This means that, in relevant ACLs, it is possible to lookup
650 the existence of a specified (or auto-generated) ratelimit key without
651 incrementing the ratelimit counter for that key.
652
653 In order for this to be useful, another ACL entry must set the rate
654 for the same key somewhere (otherwise it will always be zero).
655
656 Example:
657
658 acl_check_connect:
659 # Read the rate; if it doesn't exist or is below the maximum
660 # we update it below
661 deny ratelimit = 100 / 5m / strict / noupdate
662 log_message = RATE: $sender_rate / $sender_rate_period \
663 (max $sender_rate_limit)
664
665 [... some other logic and tests...]
666
667 warn ratelimit = 100 / 5m / strict / per_cmd
668 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
669 (max $sender_rate_limit)
670 condition = ${if le{$sender_rate}{$sender_rate_limit}}
671
672 accept
673
674 6. The variable $max_received_linelength contains the number of bytes in the
675 longest line that was received as part of the message, not counting the
676 line termination character(s).
677
678 7. Host lists can now include +ignore_defer and +include_defer, analagous to
679 +ignore_unknown and +include_unknown. These options should be used with
680 care, probably only in non-critical host lists such as whitelists.
681
682 8. There's a new option called queue_only_load_latch, which defaults true.
683 If set false when queue_only_load is greater than zero, Exim re-evaluates
684 the load for each incoming message in an SMTP session. Otherwise, once one
685 message is queued, the remainder are also.
686
687 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
688 cases when an SMTP session ends without sending QUIT. However, when Exim
689 itself is is bad trouble, such as being unable to write to its log files,
690 this ACL is not run, because it might try to do things (such as write to
691 log files) that make the situation even worse.
692
693 Like the QUIT ACL, this new ACL is provided to make it possible to gather
694 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
695 modifier is forbidden in this ACL.
696
697 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
698 to a string that indicates the reason for the termination of the SMTP
699 connection. The possible values are:
700
701 acl-drop Another ACL issued a "drop" command
702 bad-commands Too many unknown or non-mail commands
703 command-timeout Timeout while reading SMTP commands
704 connection-lost The SMTP connection has been lost
705 data-timeout Timeout while reading message data
706 local-scan-error The local_scan() function crashed
707 local-scan-timeout The local_scan() function timed out
708 signal-exit SIGTERM or SIGINT
709 synchronization-error SMTP synchronization error
710 tls-failed TLS failed to start
711
712 In most cases when an SMTP connection is closed without having received
713 QUIT, Exim sends an SMTP response message before actually closing the
714 connection. With the exception of acl-drop, the default message can be
715 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
716 "drop" verb in another ACL, it is the message from the other ACL that is
717 used.
718
719 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
720 servers with individual queries. This is done by starting the query with
721 "servers=x:y:z;", where each item in the list may take one of two forms:
722
723 (1) If it is just a host name, the appropriate global option (mysql_servers
724 or pgsql_servers) is searched for a host of the same name, and the
725 remaining parameters (database, user, password) are taken from there.
726
727 (2) If it contains any slashes, it is taken as a complete parameter set.
728
729 The list of servers is used in exactly the same was as the global list.
730 Once a connection to a server has happened and a query has been
731 successfully executed, processing of the lookup ceases.
732
733 This feature is intended for use in master/slave situations where updates
734 are occurring, and one wants to update a master rather than a slave. If the
735 masters are in the list for reading, you might have:
736
737 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
738
739 In an updating lookup, you could then write
740
741 ${lookup mysql{servers=master; UPDATE ...}
742
743 If, on the other hand, the master is not to be used for reading lookups:
744
745 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
746
747 you can still update the master by
748
749 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
750
751 11. The message_body_newlines option (default FALSE, for backwards
752 compatibility) can be used to control whether newlines are present in
753 $message_body and $message_body_end. If it is FALSE, they are replaced by
754 spaces.
755
756
757 Version 4.67
758 ------------
759
760 1. There is a new log selector called smtp_no_mail, which is not included in
761 the default setting. When it is set, a line is written to the main log
762 whenever an accepted SMTP connection terminates without having issued a
763 MAIL command.
764
765 2. When an item in a dnslists list is followed by = and & and a list of IP
766 addresses, the behaviour was not clear when the lookup returned more than
767 one IP address. This has been solved by the addition of == and =& for "all"
768 rather than the default "any" matching.
769
770 3. Up till now, the only control over which cipher suites GnuTLS uses has been
771 for the cipher algorithms. New options have been added to allow some of the
772 other parameters to be varied.
773
774 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
775 set, Exim compiles a runtime option called disable_fsync.
776
777 5. There is a new variable called $smtp_count_at_connection_start.
778
779 6. There's a new control called no_pipelining.
780
781 7. There are two new variables called $sending_ip_address and $sending_port.
782 These are set whenever an SMTP connection to another host has been set up.
783
784 8. The expansion of the helo_data option in the smtp transport now happens
785 after the connection to the server has been made.
786
787 9. There is a new expansion operator ${rfc2047d: that decodes strings that
788 are encoded as per RFC 2047.
789
790 10. There is a new log selector called "pid", which causes the current process
791 id to be added to every log line, in square brackets, immediately after the
792 time and date.
793
794 11. Exim has been modified so that it flushes SMTP output before implementing
795 a delay in an ACL. It also flushes the output before performing a callout,
796 as this can take a substantial time. These behaviours can be disabled by
797 obeying control = no_delay_flush or control = no_callout_flush,
798 respectively, at some earlier stage of the connection.
799
800 12. There are two new expansion conditions that iterate over a list. They are
801 called forany and forall.
802
803 13. There's a new global option called dsn_from that can be used to vary the
804 contents of From: lines in bounces and other automatically generated
805 messages ("delivery status notifications" - hence the name of the option).
806
807 14. The smtp transport has a new option called hosts_avoid_pipelining.
808
809 15. By default, exigrep does case-insensitive matches. There is now a -I option
810 that makes it case-sensitive.
811
812 16. A number of new features ("addresses", "map", "filter", and "reduce") have
813 been added to string expansions to make it easier to process lists of
814 items, typically addresses.
815
816 17. There's a new ACL modifier called "continue". It does nothing of itself,
817 and processing of the ACL always continues with the next condition or
818 modifier. It is provided so that the side effects of expanding its argument
819 can be used.
820
821 18. It is now possible to use newline and other control characters (those with
822 values less than 32, plus DEL) as separators in lists.
823
824 19. The exigrep utility now has a -v option, which inverts the matching
825 condition.
826
827 20. The host_find_failed option in the manualroute router can now be set to
828 "ignore".
829
830
831 Version 4.66
832 ------------
833
834 No new features were added to 4.66.
835
836
837 Version 4.65
838 ------------
839
840 No new features were added to 4.65.
841
842
843 Version 4.64
844 ------------
845
846 1. ACL variables can now be given arbitrary names, as long as they start with
847 "acl_c" or "acl_m" (for connection variables and message variables), are at
848 least six characters long, with the sixth character being either a digit or
849 an underscore.
850
851 2. There is a new ACL modifier called log_reject_target. It makes it possible
852 to specify which logs are used for messages about ACL rejections.
853
854 3. There is a new authenticator called "dovecot". This is an interface to the
855 authentication facility of the Dovecot POP/IMAP server, which can support a
856 number of authentication methods.
857
858 4. The variable $message_headers_raw provides a concatenation of all the
859 messages's headers without any decoding. This is in contrast to
860 $message_headers, which does RFC2047 decoding on the header contents.
861
862 5. In a DNS black list, if two domain names, comma-separated, are given, the
863 second is used first to do an initial check, making use of any IP value
864 restrictions that are set. If there is a match, the first domain is used,
865 without any IP value restrictions, to get the TXT record.
866
867 6. All authenticators now have a server_condition option.
868
869 7. There is a new command-line option called -Mset. It is useful only in
870 conjunction with -be (that is, when testing string expansions). It must be
871 followed by a message id; Exim loads the given message from its spool
872 before doing the expansions.
873
874 8. Another similar new command-line option is called -bem. It operates like
875 -be except that it must be followed by the name of a file that contains a
876 message.
877
878 9. When an address is delayed because of a 4xx response to a RCPT command, it
879 is now the combination of sender and recipient that is delayed in
880 subsequent queue runs until its retry time is reached.
881
882 10. Unary negation and the bitwise logical operators and, or, xor, not, and
883 shift, have been added to the eval: and eval10: expansion items.
884
885 11. The variables $interface_address and $interface_port have been renamed
886 as $received_ip_address and $received_port, to make it clear that they
887 relate to message reception rather than delivery. (The old names remain
888 available for compatibility.)
889
890 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
891 to vary the message that is sent when an SMTP command is accepted.
892
893
894 Version 4.63
895 ------------
896
897 1. There is a new Boolean option called filter_prepend_home for the redirect
898 router.
899
900 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
901 start of receiving a non-SMTP message, before any of the message has been
902 read.
903
904 3. When an SMTP error message is specified in a "message" modifier in an ACL,
905 or in a :fail: or :defer: message in a redirect router, Exim now checks the
906 start of the message for an SMTP error code.
907
908 4. There is a new parameter for LDAP lookups called "referrals", which takes
909 one of the settings "follow" (the default) or "nofollow".
910
911 5. Version 20070721.2 of exipick now included, offering these new options:
912 --reverse
913 After all other sorting options have bee processed, reverse order
914 before displaying messages (-R is synonym).
915 --random
916 Randomize order of matching messages before displaying.
917 --size
918 Instead of displaying the matching messages, display the sum
919 of their sizes.
920 --sort <variable>[,<variable>...]
921 Before displaying matching messages, sort the messages according to
922 each messages value for each variable.
923 --not
924 Negate the value for every test (returns inverse output from the
925 same criteria without --not).
926
927
928 Version 4.62
929 ------------
930
931 1. The ${readsocket expansion item now supports Internet domain sockets as well
932 as Unix domain sockets. If the first argument begins "inet:", it must be of
933 the form "inet:host:port". The port is mandatory; it may be a number or the
934 name of a TCP port in /etc/services. The host may be a name, or it may be an
935 IP address. An ip address may optionally be enclosed in square brackets.
936 This is best for IPv6 addresses. For example:
937
938 ${readsocket{inet:[::1]:1234}{<request data>}...
939
940 Only a single host name may be given, but if looking it up yield more than
941 one IP address, they are each tried in turn until a connection is made. Once
942 a connection has been made, the behaviour is as for ${readsocket with a Unix
943 domain socket.
944
945 2. If a redirect router sets up file or pipe deliveries for more than one
946 incoming address, and the relevant transport has batch_max set greater than
947 one, a batch delivery now occurs.
948
949 3. The appendfile transport has a new option called maildirfolder_create_regex.
950 Its value is a regular expression. For a maildir delivery, this is matched
951 against the maildir directory; if it matches, Exim ensures that a
952 maildirfolder file is created alongside the new, cur, and tmp directories.
953
954
955 Version 4.61
956 ------------
957
958 The documentation is up-to-date for the 4.61 release. Major new features since
959 the 4.60 release are:
960
961 . An option called disable_ipv6, to disable the use of IPv6 completely.
962
963 . An increase in the number of ACL variables to 20 of each type.
964
965 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
966 $2, $3, (though those are still set) because the numeric variables get used
967 for other things in complicated expansions.
968
969 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
970
971 . It is possible to use setclassresources() on some BSD OS to control the
972 resources used in pipe deliveries.
973
974 . A new ACL modifier called add_header, which can be used with any verb.
975
976 . More errors are detectable in retry rules.
977
978 There are a number of other additions too.
979
980
981 Version 4.60
982 ------------
983
984 The documentation is up-to-date for the 4.60 release. Major new features since
985 the 4.50 release are:
986
987 . Support for SQLite.
988
989 . Support for IGNOREQUOTA in LMTP.
990
991 . Extensions to the "submission mode" features.
992
993 . Support for Client SMTP Authorization (CSA).
994
995 . Support for ratelimiting hosts and users.
996
997 . New expansion items to help with the BATV "prvs" scheme.
998
999 . A "match_ip" condition, that matches an IP address against a list.
1000
1001 There are many more minor changes.
1002
1003 ****