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.
12 1. The new perl_taintmode option allows to run the embedded perl
13 interpreter in taint mode.
15 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
17 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
20 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
21 N can be 224, 256 (default), 384, 512.
22 With GnuTLS 3.5.0 or later, only.
24 5. Facility for named queues: A commandline argument can specify
25 the queue name for a queue operation, and an ACL modifier can set
26 the queue to be used for a message. A $queue_name variable gives
29 6. New expansion operators base32/base32d.
31 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
32 performance increase and network load decrease. Main config option
33 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
40 1. The ACL conditions regex and mime_regex now capture substrings
41 into numeric variables $regex1 to 9, like the "match" expansion condition.
43 2. New $callout_address variable records the address used for a spam=,
44 malware= or verify= callout.
46 3. Transports now take a "max_parallel" option, to limit concurrency.
48 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
49 The latter expands to a 8-element colon-sep set of hex digits including
50 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
51 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
52 The former operator strips leading zeroes and collapses the longest
53 set of 0-groups to a double-colon.
55 5. New "-bP config" support, to dump the effective configuration.
57 6. New $dkim_key_length variable.
59 7. New base64d and base64 expansion items (the existing str2b64 being a
60 synonym of the latter). Add support in base64 for certificates.
62 8. New main configuration option "bounce_return_linesize_limit" to
63 avoid oversize bodies in bounces. The dafault value matches RFC
66 9. New $initial_cwd expansion variable.
72 1. Support for using the system standard CA bundle.
74 2. New expansion items $config_file, $config_dir, containing the file
75 and directory name of the main configuration file. Also $exim_version.
77 3. New "malware=" support for Avast.
79 4. New "spam=" variant option for Rspamd.
81 5. Assorted options on malware= and spam= scanners.
83 6. A commandline option to write a comment into the logfile.
85 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
86 be configured to make connections via socks5 proxies.
88 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
89 the transmission of UTF-8 envelope addresses.
91 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
92 used encoding of Maildir folder names.
94 10. A logging option for slow DNS lookups.
96 11. New ${env {<variable>}} expansion.
98 12. A non-SMTP authenticator using information from TLS client certificates.
100 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
101 Patch originally by Wolfgang Breyha.
103 14. Main option "dns_trust_aa" for trusting your local nameserver at the
104 same level as DNSSEC.
110 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
111 DANE smtp draft to assess a secure chain of trust of the certificate
112 used to establish the TLS connection based on a TLSA record in the
113 domain of the sender.
115 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
116 and several new events have been created. The reason is because it has
117 been expanded beyond just firing events during the transport phase. Any
118 existing TPDA transport options will have to be rewritten to use a new
119 $event_name expansion variable in a condition. Refer to the
120 experimental-spec.txt for details and examples.
122 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
123 server certs used for TLS match the result of the MX lookup. It does
124 not use the same mechanism as DANE.
134 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
135 configured to expect an initial header from a proxy that will make the
136 actual external source IP:host be used in exim instead of the IP of the
137 proxy that is connecting to it.
139 2. New verify option header_names_ascii, which will check to make sure
140 there are no non-ASCII characters in header names. Exim itself handles
141 those non-ASCII characters, but downstream apps may not, so Exim can
142 detect and reject if those characters are present.
144 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
145 codepoints with valid ones.
147 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
148 command line and matching a regex against the return data for trigger
149 and a second regex to extract malware_name. The mail spoolfile name can
150 be included in the command line.
152 5. The smtp transport now supports options "tls_verify_hosts" and
153 "tls_try_verify_hosts". If either is set the certificate verification
154 is split from the encryption operation. The default remains that a failed
155 verification cancels the encryption.
157 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
158 lookup can now set a list of servers to use that is different from the
161 7. New command-line option -C for exiqgrep to specify alternate exim.conf
162 file when searching the queue.
164 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
166 9. Support for DNSSEC on outbound connections.
168 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
169 "certextract" to extract fields from them. Hash operators md5 and sha1
170 work over them for generating fingerprints, and a new sha256 operator
173 11. PRDR is now supported dy default.
175 12. OCSP stapling is now supported by default.
177 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
178 Delivery Status Notification messages in MIME format, and negociate
179 DSN features per RFC 3461.
185 1. New command-line option -bI:sieve will list all supported sieve extensions
186 of this Exim build on standard output, one per line.
187 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
188 query this to establish the correct list to include in the protocol's
189 SIEVE capability line.
191 2. If the -n option is combined with the -bP option, then the name of an
192 emitted option is not output, only the value (if visible to you).
193 For instance, "exim -n -bP pid_file_path" should just emit a pathname
194 followed by a newline, and no other text.
196 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
197 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
198 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
199 acceptable for security. (Option accepted but ignored if using OpenSSL).
200 Defaults to 1024, the old value. May be lowered only to 512, or raised as
201 far as you like. Raising this may hinder TLS interoperability with other
202 sites and is not currently recommended. Lowering this will permit you to
203 establish a TLS session which is not as secure as you might like.
205 Unless you really know what you are doing, leave it alone.
207 4. If not built with DISABLE_DNSSEC, Exim now has the main option
208 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
209 to send the DO flag to your recursive resolver. If you have a recursive
210 resolver, which can set the Authenticated Data (AD) flag in results, Exim
211 can now detect this. Exim does not perform validation itself, instead
212 relying upon a trusted path to the resolver.
214 Current status: work-in-progress; $sender_host_dnssec variable added.
216 5. DSCP support for outbound connections: on a transport using the smtp driver,
217 set "dscp = ef", for instance, to cause the connections to have the relevant
218 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
220 Similarly for inbound connections, there is a new control modifier, dscp,
221 so "warn control = dscp/ef" in the connect ACL, or after authentication.
223 Supported values depend upon system libraries. "exim -bI:dscp" to list the
224 ones Exim knows of. You can also set a raw number 0..0x3F.
226 6. The -G command-line flag is no longer ignored; it is now equivalent to an
227 ACL setting "control = suppress_local_fixups". The -L command-line flag
228 is now accepted and forces use of syslog, with the provided tag as the
229 process name. A few other flags used by Sendmail are now accepted and
232 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
233 ACL modifier; works for single-recipient mails which are recieved on and
234 deliverable via SMTP. Using the connection made for a recipient verify,
235 if requested before the verify, or a new one made for the purpose while
236 the inbound connection is still active. The bulk of the mail item is copied
237 direct from the inbound socket to the outbound (as well as the spool file).
238 When the source notifies the end of data, the data acceptance by the destination
239 is negociated before the acceptance is sent to the source. If the destination
240 does not accept the mail item, for example due to content-scanning, the item
241 is not accepted from the source and therefore there is no need to generate
242 a bounce mail. This is of benefit when providing a secondary-MX service.
243 The downside is that delays are under the control of the ultimate destination
246 The Recieved-by: header on items delivered by cutthrough is generated
247 early in reception rather than at the end; this will affect any timestamp
248 included. The log line showing delivery is recorded before that showing
249 reception; it uses a new ">>" tag instead of "=>".
251 To support the feature, verify-callout connections can now use ESMTP and TLS.
252 The usual smtp transport options are honoured, plus a (new, default everything)
253 hosts_verify_avoid_tls.
255 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
256 for specific access to the information for each connection. The old names
257 are present for now but deprecated.
259 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
261 8. New expansion operators ${listnamed:name} to get the content of a named list
262 and ${listcount:string} to count the items in a list.
264 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
265 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
266 modules. For some situations this is desirable, but we expect admin in
267 those situations to know they want the feature. More commonly, it means
268 that GUI user modules get loaded and are broken by the setuid Exim being
269 unable to access files specified in environment variables and passed
270 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
271 unless this new option is set.
273 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
274 so have also added a build option which can be used to build Exim with GnuTLS
275 but without trying to use any kind of PKCS11 support. Uncomment this in the
278 AVOID_GNUTLS_PKCS11=yes
280 10. The "acl = name" condition on an ACL now supports optional arguments.
281 New expansion item "${acl {name}{arg}...}" and expansion condition
282 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
283 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
284 Variable $acl_narg contains the number of arguments. If the ACL sets
285 a "message =" value this becomes the result of the expansion item,
286 or the value of $value for the expansion condition. If the ACL returns
287 accept the expansion condition is true; if reject, false. A defer
288 return results in a forced fail.
290 11. Routers and transports can now have multiple headers_add and headers_remove
291 option lines. The concatenated list is used.
293 12. New ACL modifier "remove_header" can remove headers before message gets
294 handled by routers/transports.
296 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
297 "aaaa" and "a" lookups is done and the full set of results returned.
299 14. New expansion variable $headers_added with content from ACL add_header
300 modifier (but not yet added to message).
302 15. New 8bitmime status logging option for received messages. Log field "M8S".
304 16. New authenticated_sender logging option, adding to log field "A".
306 17. New expansion variables $router_name and $transport_name. Useful
307 particularly for debug_print as -bt commandline option does not
308 require privilege whereas -d does.
310 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
311 proposed extension to SMTP from Eric Hall.
313 19. The pipe transport has gained the force_command option, to allow
314 decorating commands from user .forward pipe aliases with prefix
315 wrappers, for instance.
317 20. Callout connections can now AUTH; the same controls as normal delivery
320 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
321 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
322 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
323 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
324 dmarc_status. It adds new control flags dmarc_disable_verify and
325 dmarc_enable_forensic.
327 22. Add expansion variable $authenticated_fail_id, which is the username
328 provided to the authentication method which failed. It is available
329 for use in subsequent ACL processing (typically quit or notquit ACLs).
331 23. New ACL modifer "udpsend" can construct a UDP packet to send to a given
334 24. New ${hexquote:..string..} expansion operator converts non-printable
335 characters in the string to \xNN form.
337 25. Experimental TPDA (Transport Post Delivery Action) function added.
338 Patch provided by Axel Rau.
340 26. Experimental Redis lookup added. Patch provided by Warren Baker.
346 1. New authenticator driver, "gsasl". Server-only (at present).
347 This is a SASL interface, licensed under GPL, which can be found at
348 http://www.gnu.org/software/gsasl/.
349 This system does not provide sources of data for authentication, so
350 careful use needs to be made of the conditions in Exim.
352 2. New authenticator driver, "heimdal_gssapi". Server-only.
353 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
354 is no longer honoured for setuid programs by Heimdal. Use the
355 "server_keytab" option to point to the keytab.
357 3. The "pkg-config" system can now be used when building Exim to reference
358 cflags and library information for lookups and authenticators, rather
359 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
360 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
361 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
363 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
364 find the headers and libraries for PCRE.
366 4. New expansion variable $tls_bits.
368 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
369 be joined together with ASCII NUL characters to construct the key to pass
370 into the DBM library. Can be used with gsasl to access sasldb2 files as
373 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
375 Avoid release 1.0.1a if you can. Note that the default value of
376 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
377 increased susceptibility to attack. This may still have interoperability
378 implications for very old clients (see version 4.31 change 37) but
379 administrators can choose to make the trade-off themselves and restore
380 compatibility at the cost of session security.
382 7. Use of the new expansion variable $tls_sni in the main configuration option
383 tls_certificate will cause Exim to re-expand the option, if the client
384 sends the TLS Server Name Indication extension, to permit choosing a
385 different certificate; tls_privatekey will also be re-expanded. You must
386 still set these options to expand to valid files when $tls_sni is not set.
388 The SMTP Transport has gained the option tls_sni, which will set a hostname
389 for outbound TLS sessions, and set $tls_sni too.
391 A new log_selector, +tls_sni, has been added, to log received SNI values
392 for Exim as a server.
394 8. The existing "accept_8bitmime" option now defaults to true. This means
395 that Exim is deliberately not strictly RFC compliant. We're following
396 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
397 Those who disagree, or know that they are talking to mail servers that,
398 even today, are not 8-bit clean, need to turn off this option.
400 9. Exim can now be started with -bw (with an optional timeout, given as
401 -bw<timespec>). With this, stdin at startup is a socket that is
402 already listening for connections. This has a more modern name of
403 "socket activation", but forcing the activated socket to fd 0. We're
404 interested in adding more support for modern variants.
406 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
407 for numbers indicates multiplication by 1024^3.
409 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
410 gnutls_require_mac & gnutls_require_protocols are no longer supported.
411 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
412 string, documentation for which is at:
413 http://www.gnutls.org/manual/html_node/Priority-Strings.html
415 SNI support has been added to Exim's GnuTLS integration too.
417 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
418 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
420 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
421 is now available. If the contents of the file are valid, then Exim will
422 send that back in response to a TLS status request; this is OCSP Stapling.
423 Exim will not maintain the contents of the file in any way: administrators
424 are responsible for ensuring that it is up-to-date.
426 See "experimental-spec.txt" for more details.
428 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
429 identically to TXT record lookups.
431 14. New expansion variable $tod_epoch_l for higher-precision time.
433 15. New global option tls_dh_max_bits, defaulting to current value of NSS
434 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
435 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
437 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
438 Option can now be a path or an identifier for a standard prime.
439 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
440 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
443 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
444 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
445 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
451 1. New options for the ratelimit ACL condition: /count= and /unique=.
452 The /noupdate option has been replaced by a /readonly option.
454 2. The SMTP transport's protocol option may now be set to "smtps", to
455 use SSL-on-connect outbound.
457 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
458 there is a problem talking to the AV scanner, or the AV scanner running.
460 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
461 and check if the search item is a member of the list. This does not
462 support named lists, but does subject the list part to string expansion.
464 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
465 built, Exim no longer performs string expansion on the second string of
466 the match_* expansion conditions: "match_address", "match_domain",
467 "match_ip" & "match_local_part". Named lists can still be used.
473 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
474 or off in the resolver library.
480 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
481 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
482 libraries. The following global options have been added in support of
483 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
484 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
486 2. The pipe transport now takes a boolean option, "freeze_signal", default
487 false. When true, if the external delivery command exits on a signal then
488 Exim will freeze the message in the queue, instead of generating a bounce.
490 3. Log filenames may now use %M as an escape, instead of %D (still available).
491 The %M pattern expands to yyyymm, providing month-level resolution.
493 4. The $message_linecount variable is now updated for the maildir_tag option,
494 in the same way as $message_size, to reflect the real number of lines,
495 including any header additions or removals from transport.
497 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
498 Exim now selects entries randomly, to better scale in a cluster setup.
504 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
505 the flaw permitted the Exim run-time user to cause root to append to
506 arbitrary files of the attacker's choosing, with the content based
507 on content supplied by the attacker.
509 2. Exim now supports loading some lookup types at run-time, using your
510 platform's dlopen() functionality. This has limited platform support
511 and the intention is not to support every variant, it's limited to
512 dlopen(). This permits the main Exim binary to not be linked against
513 all the libraries needed for all the lookup types.
519 NOTE: this version is not guaranteed backwards-compatible, please read the
520 items below carefully
522 1. A new main configuration option, "openssl_options", is available if Exim
523 is built with SSL support provided by OpenSSL. The option allows
524 administrators to specify OpenSSL options to be used on connections;
525 typically this is to set bug compatibility features which the OpenSSL
526 developers have not enabled by default. There may be security
527 consequences for certain options, so these should not be changed
530 2. A new pipe transport option, "permit_coredumps", may help with problem
531 diagnosis in some scenarios. Note that Exim is typically installed as
532 a setuid binary, which on most OSes will inhibit coredumps by default,
533 so that safety mechanism would have to be overridden for this option to
534 be able to take effect.
536 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
537 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
538 Note that this switches Exim to use a new API ("INSTREAM") and a future
539 release of ClamAV will remove support for the old API ("STREAM").
541 The av_scanner option, when set to "clamd", now takes an optional third
542 part, "local", which causes Exim to pass a filename to ClamAV instead of
543 the file content. This is the same behaviour as when clamd is pointed at
544 a Unix-domain socket. For example:
546 av_scanner = clamd:192.0.2.3 1234:local
548 ClamAV's ExtendedDetectionInfo response format is now handled.
550 4. There is now a -bmalware option, restricted to admin users. This option
551 takes one parameter, a filename, and scans that file with Exim's
552 malware-scanning framework. This is intended purely as a debugging aid
553 to ensure that Exim's scanning is working, not to replace other tools.
554 Note that the ACL framework is not invoked, so if av_scanner references
555 ACL variables without a fallback then this will fail.
557 5. There is a new expansion operator, "reverse_ip", which will reverse IP
558 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
560 ${reverse_ip:192.0.2.4}
562 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
563 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
565 6. There is a new ACL control called "debug", to enable debug logging.
566 This allows selective logging of certain incoming transactions within
567 production environments, with some care. It takes two options, "tag"
568 and "opts"; "tag" is included in the filename of the log and "opts"
569 is used as per the -d<options> command-line option. Examples, which
570 don't all make sense in all contexts:
573 control = debug/tag=.$sender_host_address
574 control = debug/opts=+expand+acl
575 control = debug/tag=.$message_exim_id/opts=+expand
577 7. It has always been implicit in the design and the documentation that
578 "the Exim user" is not root. src/EDITME said that using root was
579 "very strongly discouraged". This is not enough to keep people from
580 shooting themselves in the foot in days when many don't configure Exim
581 themselves but via package build managers. The security consequences of
582 running various bits of network code are severe if there should be bugs in
583 them. As such, the Exim user may no longer be root. If configured
584 statically, Exim will refuse to build. If configured as ref:user then Exim
585 will exit shortly after start-up. If you must shoot yourself in the foot,
586 then henceforth you will have to maintain your own local patches to strip
589 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
590 condition logic to determine truth/failure and will fail to expand many
591 strings, bool_lax{} uses the router condition logic, where most strings
593 Note: bool{00} is false, bool_lax{00} is true.
595 9. Routers now support multiple "condition" tests.
597 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
598 Setting this allows an admin to define which entry in the tcpwrappers
599 config file will be used to control access to the daemon. This option
600 is only available when Exim is built with USE_TCP_WRAPPERS. The
601 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
604 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
605 the Exim run-time user, instead of root.
607 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
608 is forced on. This is mitigated by the new build option
609 TRUSTED_CONFIG_LIST which defines a list of configuration files which
610 are trusted; one per line. If a config file is owned by root and matches
611 a pathname in the list, then it may be invoked by the Exim build-time
612 user without Exim relinquishing root privileges.
614 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
615 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
616 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
617 include the main config. As a transition mechanism, we are temporarily
618 providing a work-around: the new build option WHITELIST_D_MACROS provides
619 a colon-separated list of macro names which may be overridden by the Exim
620 run-time user. The values of these macros are constrained to the regex
621 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
627 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
628 writable, the other to locking of MBX folders (not mbox).
630 2. MySQL stored procedures are now supported.
632 3. The dkim_domain transport option is now a list, not a single string, and
633 messages will be signed for each element in the list (discarding
636 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
637 in the presence of multiple character strings within the RR. Prior to 4.70,
638 only the first string would be returned. The dnsdb lookup now, by default,
639 preserves the pre-4.70 semantics, but also now takes an extended output
640 separator specification. The separator can be followed by a semicolon, to
641 concatenate the individual text strings together with no join character,
642 or by a comma and a second separator character, in which case the text
643 strings within a TXT record are joined on that second character.
644 Administrators are reminded that DNS provides no ordering guarantees
645 between multiple records in an RRset. For example:
647 foo.example. IN TXT "a" "b" "c"
648 foo.example. IN TXT "d" "e" "f"
650 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
651 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
652 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
658 1. Native DKIM support without an external library.
659 (Note that if no action to prevent it is taken, a straight upgrade will
660 result in DKIM verification of all signed incoming emails. See spec
661 for details on conditionally disabling)
663 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
665 3. There is now a bool{} expansion condition which maps certain strings to
666 true/false condition values (most likely of use in conjunction with the
667 and{} expansion operator).
669 4. The $spam_score, $spam_bar and $spam_report variables are now available
672 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
673 options, provided that Exim is invoked by an admin_user.
675 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
676 which increases compatibility with older clients at the cost of decreased
677 security. Don't set this unless you need to support such clients.
679 7. There is a new expansion operator, ${randint:...} which will produce a
680 "random" number less than the supplied integer. This randomness is
681 not guaranteed to be cryptographically strong, but depending upon how
682 Exim was built may be better than the most naive schemes.
684 8. Exim now explicitly ensures that SHA256 is available when linked against
687 9. The transport_filter_timeout option now applies to SMTP transports too.
693 1. Preliminary DKIM support in Experimental.
699 1. The body_linecount and body_zerocount C variables are now exported in the
702 2. When a dnslists lookup succeeds, the key that was looked up is now placed
703 in $dnslist_matched. When the key is an IP address, it is not reversed in
704 this variable (though it is, of course, in the actual lookup). In simple
707 deny dnslists = spamhaus.example
709 the key is also available in another variable (in this case,
710 $sender_host_address). In more complicated cases, however, this is not
711 true. For example, using a data lookup might generate a dnslists lookup
714 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
716 If this condition succeeds, the value in $dnslist_matched might be
717 192.168.6.7 (for example).
719 3. Authenticators now have a client_condition option. When Exim is running as
720 a client, it skips an authenticator whose client_condition expansion yields
721 "0", "no", or "false". This can be used, for example, to skip plain text
722 authenticators when the connection is not encrypted by a setting such as:
724 client_condition = ${if !eq{$tls_cipher}{}}
726 Note that the 4.67 documentation states that $tls_cipher contains the
727 cipher used for incoming messages. In fact, during SMTP delivery, it
728 contains the cipher used for the delivery. The same is true for
731 4. There is now a -Mvc <message-id> option, which outputs a copy of the
732 message to the standard output, in RFC 2822 format. The option can be used
733 only by an admin user.
735 5. There is now a /noupdate option for the ratelimit ACL condition. It
736 computes the rate and checks the limit as normal, but it does not update
737 the saved data. This means that, in relevant ACLs, it is possible to lookup
738 the existence of a specified (or auto-generated) ratelimit key without
739 incrementing the ratelimit counter for that key.
741 In order for this to be useful, another ACL entry must set the rate
742 for the same key somewhere (otherwise it will always be zero).
747 # Read the rate; if it doesn't exist or is below the maximum
749 deny ratelimit = 100 / 5m / strict / noupdate
750 log_message = RATE: $sender_rate / $sender_rate_period \
751 (max $sender_rate_limit)
753 [... some other logic and tests...]
755 warn ratelimit = 100 / 5m / strict / per_cmd
756 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
757 (max $sender_rate_limit)
758 condition = ${if le{$sender_rate}{$sender_rate_limit}}
762 6. The variable $max_received_linelength contains the number of bytes in the
763 longest line that was received as part of the message, not counting the
764 line termination character(s).
766 7. Host lists can now include +ignore_defer and +include_defer, analagous to
767 +ignore_unknown and +include_unknown. These options should be used with
768 care, probably only in non-critical host lists such as whitelists.
770 8. There's a new option called queue_only_load_latch, which defaults true.
771 If set false when queue_only_load is greater than zero, Exim re-evaluates
772 the load for each incoming message in an SMTP session. Otherwise, once one
773 message is queued, the remainder are also.
775 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
776 cases when an SMTP session ends without sending QUIT. However, when Exim
777 itself is is bad trouble, such as being unable to write to its log files,
778 this ACL is not run, because it might try to do things (such as write to
779 log files) that make the situation even worse.
781 Like the QUIT ACL, this new ACL is provided to make it possible to gather
782 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
783 modifier is forbidden in this ACL.
785 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
786 to a string that indicates the reason for the termination of the SMTP
787 connection. The possible values are:
789 acl-drop Another ACL issued a "drop" command
790 bad-commands Too many unknown or non-mail commands
791 command-timeout Timeout while reading SMTP commands
792 connection-lost The SMTP connection has been lost
793 data-timeout Timeout while reading message data
794 local-scan-error The local_scan() function crashed
795 local-scan-timeout The local_scan() function timed out
796 signal-exit SIGTERM or SIGINT
797 synchronization-error SMTP synchronization error
798 tls-failed TLS failed to start
800 In most cases when an SMTP connection is closed without having received
801 QUIT, Exim sends an SMTP response message before actually closing the
802 connection. With the exception of acl-drop, the default message can be
803 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
804 "drop" verb in another ACL, it is the message from the other ACL that is
807 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
808 servers with individual queries. This is done by starting the query with
809 "servers=x:y:z;", where each item in the list may take one of two forms:
811 (1) If it is just a host name, the appropriate global option (mysql_servers
812 or pgsql_servers) is searched for a host of the same name, and the
813 remaining parameters (database, user, password) are taken from there.
815 (2) If it contains any slashes, it is taken as a complete parameter set.
817 The list of servers is used in exactly the same was as the global list.
818 Once a connection to a server has happened and a query has been
819 successfully executed, processing of the lookup ceases.
821 This feature is intended for use in master/slave situations where updates
822 are occurring, and one wants to update a master rather than a slave. If the
823 masters are in the list for reading, you might have:
825 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
827 In an updating lookup, you could then write
829 ${lookup mysql{servers=master; UPDATE ...}
831 If, on the other hand, the master is not to be used for reading lookups:
833 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
835 you can still update the master by
837 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
839 11. The message_body_newlines option (default FALSE, for backwards
840 compatibility) can be used to control whether newlines are present in
841 $message_body and $message_body_end. If it is FALSE, they are replaced by
848 1. There is a new log selector called smtp_no_mail, which is not included in
849 the default setting. When it is set, a line is written to the main log
850 whenever an accepted SMTP connection terminates without having issued a
853 2. When an item in a dnslists list is followed by = and & and a list of IP
854 addresses, the behaviour was not clear when the lookup returned more than
855 one IP address. This has been solved by the addition of == and =& for "all"
856 rather than the default "any" matching.
858 3. Up till now, the only control over which cipher suites GnuTLS uses has been
859 for the cipher algorithms. New options have been added to allow some of the
860 other parameters to be varied.
862 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
863 set, Exim compiles a runtime option called disable_fsync.
865 5. There is a new variable called $smtp_count_at_connection_start.
867 6. There's a new control called no_pipelining.
869 7. There are two new variables called $sending_ip_address and $sending_port.
870 These are set whenever an SMTP connection to another host has been set up.
872 8. The expansion of the helo_data option in the smtp transport now happens
873 after the connection to the server has been made.
875 9. There is a new expansion operator ${rfc2047d: that decodes strings that
876 are encoded as per RFC 2047.
878 10. There is a new log selector called "pid", which causes the current process
879 id to be added to every log line, in square brackets, immediately after the
882 11. Exim has been modified so that it flushes SMTP output before implementing
883 a delay in an ACL. It also flushes the output before performing a callout,
884 as this can take a substantial time. These behaviours can be disabled by
885 obeying control = no_delay_flush or control = no_callout_flush,
886 respectively, at some earlier stage of the connection.
888 12. There are two new expansion conditions that iterate over a list. They are
889 called forany and forall.
891 13. There's a new global option called dsn_from that can be used to vary the
892 contents of From: lines in bounces and other automatically generated
893 messages ("delivery status notifications" - hence the name of the option).
895 14. The smtp transport has a new option called hosts_avoid_pipelining.
897 15. By default, exigrep does case-insensitive matches. There is now a -I option
898 that makes it case-sensitive.
900 16. A number of new features ("addresses", "map", "filter", and "reduce") have
901 been added to string expansions to make it easier to process lists of
902 items, typically addresses.
904 17. There's a new ACL modifier called "continue". It does nothing of itself,
905 and processing of the ACL always continues with the next condition or
906 modifier. It is provided so that the side effects of expanding its argument
909 18. It is now possible to use newline and other control characters (those with
910 values less than 32, plus DEL) as separators in lists.
912 19. The exigrep utility now has a -v option, which inverts the matching
915 20. The host_find_failed option in the manualroute router can now be set to
922 No new features were added to 4.66.
928 No new features were added to 4.65.
934 1. ACL variables can now be given arbitrary names, as long as they start with
935 "acl_c" or "acl_m" (for connection variables and message variables), are at
936 least six characters long, with the sixth character being either a digit or
939 2. There is a new ACL modifier called log_reject_target. It makes it possible
940 to specify which logs are used for messages about ACL rejections.
942 3. There is a new authenticator called "dovecot". This is an interface to the
943 authentication facility of the Dovecot POP/IMAP server, which can support a
944 number of authentication methods.
946 4. The variable $message_headers_raw provides a concatenation of all the
947 messages's headers without any decoding. This is in contrast to
948 $message_headers, which does RFC2047 decoding on the header contents.
950 5. In a DNS black list, if two domain names, comma-separated, are given, the
951 second is used first to do an initial check, making use of any IP value
952 restrictions that are set. If there is a match, the first domain is used,
953 without any IP value restrictions, to get the TXT record.
955 6. All authenticators now have a server_condition option.
957 7. There is a new command-line option called -Mset. It is useful only in
958 conjunction with -be (that is, when testing string expansions). It must be
959 followed by a message id; Exim loads the given message from its spool
960 before doing the expansions.
962 8. Another similar new command-line option is called -bem. It operates like
963 -be except that it must be followed by the name of a file that contains a
966 9. When an address is delayed because of a 4xx response to a RCPT command, it
967 is now the combination of sender and recipient that is delayed in
968 subsequent queue runs until its retry time is reached.
970 10. Unary negation and the bitwise logical operators and, or, xor, not, and
971 shift, have been added to the eval: and eval10: expansion items.
973 11. The variables $interface_address and $interface_port have been renamed
974 as $received_ip_address and $received_port, to make it clear that they
975 relate to message reception rather than delivery. (The old names remain
976 available for compatibility.)
978 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
979 to vary the message that is sent when an SMTP command is accepted.
985 1. There is a new Boolean option called filter_prepend_home for the redirect
988 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
989 start of receiving a non-SMTP message, before any of the message has been
992 3. When an SMTP error message is specified in a "message" modifier in an ACL,
993 or in a :fail: or :defer: message in a redirect router, Exim now checks the
994 start of the message for an SMTP error code.
996 4. There is a new parameter for LDAP lookups called "referrals", which takes
997 one of the settings "follow" (the default) or "nofollow".
999 5. Version 20070721.2 of exipick now included, offering these new options:
1001 After all other sorting options have bee processed, reverse order
1002 before displaying messages (-R is synonym).
1004 Randomize order of matching messages before displaying.
1006 Instead of displaying the matching messages, display the sum
1008 --sort <variable>[,<variable>...]
1009 Before displaying matching messages, sort the messages according to
1010 each messages value for each variable.
1012 Negate the value for every test (returns inverse output from the
1013 same criteria without --not).
1019 1. The ${readsocket expansion item now supports Internet domain sockets as well
1020 as Unix domain sockets. If the first argument begins "inet:", it must be of
1021 the form "inet:host:port". The port is mandatory; it may be a number or the
1022 name of a TCP port in /etc/services. The host may be a name, or it may be an
1023 IP address. An ip address may optionally be enclosed in square brackets.
1024 This is best for IPv6 addresses. For example:
1026 ${readsocket{inet:[::1]:1234}{<request data>}...
1028 Only a single host name may be given, but if looking it up yield more than
1029 one IP address, they are each tried in turn until a connection is made. Once
1030 a connection has been made, the behaviour is as for ${readsocket with a Unix
1033 2. If a redirect router sets up file or pipe deliveries for more than one
1034 incoming address, and the relevant transport has batch_max set greater than
1035 one, a batch delivery now occurs.
1037 3. The appendfile transport has a new option called maildirfolder_create_regex.
1038 Its value is a regular expression. For a maildir delivery, this is matched
1039 against the maildir directory; if it matches, Exim ensures that a
1040 maildirfolder file is created alongside the new, cur, and tmp directories.
1046 The documentation is up-to-date for the 4.61 release. Major new features since
1047 the 4.60 release are:
1049 . An option called disable_ipv6, to disable the use of IPv6 completely.
1051 . An increase in the number of ACL variables to 20 of each type.
1053 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1054 $2, $3, (though those are still set) because the numeric variables get used
1055 for other things in complicated expansions.
1057 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1059 . It is possible to use setclassresources() on some BSD OS to control the
1060 resources used in pipe deliveries.
1062 . A new ACL modifier called add_header, which can be used with any verb.
1064 . More errors are detectable in retry rules.
1066 There are a number of other additions too.
1072 The documentation is up-to-date for the 4.60 release. Major new features since
1073 the 4.50 release are:
1075 . Support for SQLite.
1077 . Support for IGNOREQUOTA in LMTP.
1079 . Extensions to the "submission mode" features.
1081 . Support for Client SMTP Authorization (CSA).
1083 . Support for ratelimiting hosts and users.
1085 . New expansion items to help with the BATV "prvs" scheme.
1087 . A "match_ip" condition, that matches an IP address against a list.
1089 There are many more minor changes.
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