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 Git before the documentation is updated. Once
7 the documentation is updated, this file is reduced to a short list.
12 1. PKG_CONFIG_PATH can now be set in Local/Makefile;
13 wildcards will be expanded, values are collapsed.
15 2. The ${readsocket } expansion now takes an option to not shutdown the
16 connection after sending the query string. The default remains to do so.
18 3. An smtp transport option "hosts_noproxy_tls" to control whether multiple
19 deliveries on a single TCP connection can maintain a TLS connection
20 open. By default disabled for all hosts, doing so saves the cost of
21 making new TLS sessions, at the cost of having to proxy the data via
22 another process. Logging is also affected.
24 4. A malware connection type for the FPSCAND protocol.
26 5. An option for recipient verify callouts to hold the connection open for
27 further recipients and for delivery.
29 6. The reproducible build $SOURCE_DATE_EPOCH environment variable is now
32 7. Optionally, an alternate format for spool data-files which matches the
33 wire format - meaning more efficient reception and transmission (at the
34 cost of difficulty with standard Unix tools). Only used for messages
35 received using the ESMTP CHUNKING option, and when a new main-section
36 option "spool_wireformat" (false by default) is set.
38 8. New main configuration option "commandline_checks_require_admin" to
39 restrict who can use various introspection options.
41 9. New option modifier "no_check" for quota and quota_filecount
44 10. Variable $smtp_command_history returning a comma-sep list of recent
47 11. Millisecond timetamps in logs, on log_selector "millisec". Also affects
48 log elements QT, DT and D, and timstamps in debug output.
54 1. Allow relative config file names for ".include"
56 2. A main-section config option "debug_store" to control the checks on
57 variable locations during store-reset. Normally false but can be enabled
58 when a memory corrution issue is suspected on a production system.
64 1. The new perl_taintmode option allows to run the embedded perl
65 interpreter in taint mode.
67 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
69 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
72 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
73 N can be 224, 256 (default), 384, 512.
74 With GnuTLS 3.5.0 or later, only.
76 5. Facility for named queues: A command-line argument can specify
77 the queue name for a queue operation, and an ACL modifier can set
78 the queue to be used for a message. A $queue_name variable gives
81 6. New expansion operators base32/base32d.
83 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
84 performance increase and network load decrease. Main config option
85 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
88 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
90 9. Expansion operator escape8bit, like escape but not touching newline etc..
92 10. Feature macros, generated from compile options. All start with "_HAVE_"
93 and go on with some roughly recognisable name. Driver macros, for
94 router, transport and authentication drivers; names starting with "_DRIVER_".
95 Option macros, for each configuration-file option; all start with "_OPT_".
96 Use the "-bP macros" command-line option to see what is present.
98 11. Integer values for options can take a "G" multiplier.
100 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
101 returns from the target back to the initiator, rather than spooling the
104 13. New built-in constants available for tls_dhparam and default changed.
106 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
107 out copies of the message spool files for use by 3rd-party scanners.
109 15. A new option on the smtp transport, hosts_try_fastopen. If the system
110 supports it (on Linux it must be enabled in the kernel by the sysadmin)
111 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
112 but it permits a peer that also supports the facility to send its SMTP
113 banner immediately after the SYN,ACK segment rather then waiting for
114 another ACK - so saving up to one roundtrip time. Because it requires
115 previous communication with the peer (we save a cookie from it) this
116 will only become active on frequently-contacted destinations.
118 16. A new syslog_pid option to suppress PID duplication in syslog lines.
124 1. The ACL conditions regex and mime_regex now capture substrings
125 into numeric variables $regex1 to 9, like the "match" expansion condition.
127 2. New $callout_address variable records the address used for a spam=,
128 malware= or verify= callout.
130 3. Transports now take a "max_parallel" option, to limit concurrency.
132 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
133 The latter expands to a 8-element colon-sep set of hex digits including
134 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
135 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
136 The former operator strips leading zeroes and collapses the longest
137 set of 0-groups to a double-colon.
139 5. New "-bP config" support, to dump the effective configuration.
141 6. New $dkim_key_length variable.
143 7. New base64d and base64 expansion items (the existing str2b64 being a
144 synonym of the latter). Add support in base64 for certificates.
146 8. New main configuration option "bounce_return_linesize_limit" to
147 avoid oversize bodies in bounces. The default value matches RFC
150 9. New $initial_cwd expansion variable.
156 1. Support for using the system standard CA bundle.
158 2. New expansion items $config_file, $config_dir, containing the file
159 and directory name of the main configuration file. Also $exim_version.
161 3. New "malware=" support for Avast.
163 4. New "spam=" variant option for Rspamd.
165 5. Assorted options on malware= and spam= scanners.
167 6. A command-line option to write a comment into the logfile.
169 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
170 be configured to make connections via socks5 proxies.
172 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
173 the transmission of UTF-8 envelope addresses.
175 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
176 used encoding of Maildir folder names.
178 10. A logging option for slow DNS lookups.
180 11. New ${env {<variable>}} expansion.
182 12. A non-SMTP authenticator using information from TLS client certificates.
184 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
185 Patch originally by Wolfgang Breyha.
187 14. Main option "dns_trust_aa" for trusting your local nameserver at the
188 same level as DNSSEC.
194 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
195 DANE SMTP draft to assess a secure chain of trust of the certificate
196 used to establish the TLS connection based on a TLSA record in the
197 domain of the sender.
199 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
200 and several new events have been created. The reason is because it has
201 been expanded beyond just firing events during the transport phase. Any
202 existing TPDA transport options will have to be rewritten to use a new
203 $event_name expansion variable in a condition. Refer to the
204 experimental-spec.txt for details and examples.
206 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
207 server certs used for TLS match the result of the MX lookup. It does
208 not use the same mechanism as DANE.
218 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
219 configured to expect an initial header from a proxy that will make the
220 actual external source IP:host be used in exim instead of the IP of the
221 proxy that is connecting to it.
223 2. New verify option header_names_ascii, which will check to make sure
224 there are no non-ASCII characters in header names. Exim itself handles
225 those non-ASCII characters, but downstream apps may not, so Exim can
226 detect and reject if those characters are present.
228 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
229 codepoints with valid ones.
231 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
232 command line and matching a regex against the return data for trigger
233 and a second regex to extract malware_name. The mail spoolfile name can
234 be included in the command line.
236 5. The smtp transport now supports options "tls_verify_hosts" and
237 "tls_try_verify_hosts". If either is set the certificate verification
238 is split from the encryption operation. The default remains that a failed
239 verification cancels the encryption.
241 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
242 lookup can now set a list of servers to use that is different from the
245 7. New command-line option -C for exiqgrep to specify alternate exim.conf
246 file when searching the queue.
248 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
250 9. Support for DNSSEC on outbound connections.
252 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
253 "certextract" to extract fields from them. Hash operators md5 and sha1
254 work over them for generating fingerprints, and a new sha256 operator
257 11. PRDR is now supported dy default.
259 12. OCSP stapling is now supported by default.
261 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
262 Delivery Status Notification messages in MIME format, and negotiate
263 DSN features per RFC 3461.
269 1. New command-line option -bI:sieve will list all supported sieve extensions
270 of this Exim build on standard output, one per line.
271 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
272 query this to establish the correct list to include in the protocol's
273 SIEVE capability line.
275 2. If the -n option is combined with the -bP option, then the name of an
276 emitted option is not output, only the value (if visible to you).
277 For instance, "exim -n -bP pid_file_path" should just emit a pathname
278 followed by a newline, and no other text.
280 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
281 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
282 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
283 acceptable for security. (Option accepted but ignored if using OpenSSL).
284 Defaults to 1024, the old value. May be lowered only to 512, or raised as
285 far as you like. Raising this may hinder TLS interoperability with other
286 sites and is not currently recommended. Lowering this will permit you to
287 establish a TLS session which is not as secure as you might like.
289 Unless you really know what you are doing, leave it alone.
291 4. If not built with DISABLE_DNSSEC, Exim now has the main option
292 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
293 to send the DO flag to your recursive resolver. If you have a recursive
294 resolver, which can set the Authenticated Data (AD) flag in results, Exim
295 can now detect this. Exim does not perform validation itself, instead
296 relying upon a trusted path to the resolver.
298 Current status: work-in-progress; $sender_host_dnssec variable added.
300 5. DSCP support for outbound connections: on a transport using the smtp driver,
301 set "dscp = ef", for instance, to cause the connections to have the relevant
302 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
304 Similarly for inbound connections, there is a new control modifier, dscp,
305 so "warn control = dscp/ef" in the connect ACL, or after authentication.
307 Supported values depend upon system libraries. "exim -bI:dscp" to list the
308 ones Exim knows of. You can also set a raw number 0..0x3F.
310 6. The -G command-line flag is no longer ignored; it is now equivalent to an
311 ACL setting "control = suppress_local_fixups". The -L command-line flag
312 is now accepted and forces use of syslog, with the provided tag as the
313 process name. A few other flags used by Sendmail are now accepted and
316 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
317 ACL modifier; works for single-recipient mails which are received on and
318 deliverable via SMTP. Using the connection made for a recipient verify,
319 if requested before the verify, or a new one made for the purpose while
320 the inbound connection is still active. The bulk of the mail item is copied
321 direct from the inbound socket to the outbound (as well as the spool file).
322 When the source notifies the end of data, the data acceptance by the destination
323 is negotiated before the acceptance is sent to the source. If the destination
324 does not accept the mail item, for example due to content-scanning, the item
325 is not accepted from the source and therefore there is no need to generate
326 a bounce mail. This is of benefit when providing a secondary-MX service.
327 The downside is that delays are under the control of the ultimate destination
330 The Received-by: header on items delivered by cutthrough is generated
331 early in reception rather than at the end; this will affect any timestamp
332 included. The log line showing delivery is recorded before that showing
333 reception; it uses a new ">>" tag instead of "=>".
335 To support the feature, verify-callout connections can now use ESMTP and TLS.
336 The usual smtp transport options are honoured, plus a (new, default everything)
337 hosts_verify_avoid_tls.
339 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
340 for specific access to the information for each connection. The old names
341 are present for now but deprecated.
343 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
345 8. New expansion operators ${listnamed:name} to get the content of a named list
346 and ${listcount:string} to count the items in a list.
348 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
349 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
350 modules. For some situations this is desirable, but we expect admin in
351 those situations to know they want the feature. More commonly, it means
352 that GUI user modules get loaded and are broken by the setuid Exim being
353 unable to access files specified in environment variables and passed
354 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
355 unless this new option is set.
357 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
358 so have also added a build option which can be used to build Exim with GnuTLS
359 but without trying to use any kind of PKCS11 support. Uncomment this in the
362 AVOID_GNUTLS_PKCS11=yes
364 10. The "acl = name" condition on an ACL now supports optional arguments.
365 New expansion item "${acl {name}{arg}...}" and expansion condition
366 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
367 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
368 Variable $acl_narg contains the number of arguments. If the ACL sets
369 a "message =" value this becomes the result of the expansion item,
370 or the value of $value for the expansion condition. If the ACL returns
371 accept the expansion condition is true; if reject, false. A defer
372 return results in a forced fail.
374 11. Routers and transports can now have multiple headers_add and headers_remove
375 option lines. The concatenated list is used.
377 12. New ACL modifier "remove_header" can remove headers before message gets
378 handled by routers/transports.
380 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
381 "aaaa" and "a" lookups is done and the full set of results returned.
383 14. New expansion variable $headers_added with content from ACL add_header
384 modifier (but not yet added to message).
386 15. New 8bitmime status logging option for received messages. Log field "M8S".
388 16. New authenticated_sender logging option, adding to log field "A".
390 17. New expansion variables $router_name and $transport_name. Useful
391 particularly for debug_print as -bt command-line option does not
392 require privilege whereas -d does.
394 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
395 proposed extension to SMTP from Eric Hall.
397 19. The pipe transport has gained the force_command option, to allow
398 decorating commands from user .forward pipe aliases with prefix
399 wrappers, for instance.
401 20. Callout connections can now AUTH; the same controls as normal delivery
404 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
405 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
406 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
407 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
408 dmarc_status. It adds new control flags dmarc_disable_verify and
409 dmarc_enable_forensic. The default for the dmarc_tld_file option is
410 "/etc/exim/opendmarc.tlds" and can be changed via EDITME.
412 22. Add expansion variable $authenticated_fail_id, which is the username
413 provided to the authentication method which failed. It is available
414 for use in subsequent ACL processing (typically quit or notquit ACLs).
416 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
419 24. New ${hexquote:..string..} expansion operator converts non-printable
420 characters in the string to \xNN form.
422 25. Experimental TPDA (Transport Post Delivery Action) function added.
423 Patch provided by Axel Rau.
425 26. Experimental Redis lookup added. Patch provided by Warren Baker.
431 1. New authenticator driver, "gsasl". Server-only (at present).
432 This is a SASL interface, licensed under GPL, which can be found at
433 http://www.gnu.org/software/gsasl/.
434 This system does not provide sources of data for authentication, so
435 careful use needs to be made of the conditions in Exim.
437 2. New authenticator driver, "heimdal_gssapi". Server-only.
438 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
439 is no longer honoured for setuid programs by Heimdal. Use the
440 "server_keytab" option to point to the keytab.
442 3. The "pkg-config" system can now be used when building Exim to reference
443 cflags and library information for lookups and authenticators, rather
444 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
445 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
446 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
448 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
449 find the headers and libraries for PCRE.
451 4. New expansion variable $tls_bits.
453 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
454 be joined together with ASCII NUL characters to construct the key to pass
455 into the DBM library. Can be used with gsasl to access sasldb2 files as
458 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
460 Avoid release 1.0.1a if you can. Note that the default value of
461 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
462 increased susceptibility to attack. This may still have interoperability
463 implications for very old clients (see version 4.31 change 37) but
464 administrators can choose to make the trade-off themselves and restore
465 compatibility at the cost of session security.
467 7. Use of the new expansion variable $tls_sni in the main configuration option
468 tls_certificate will cause Exim to re-expand the option, if the client
469 sends the TLS Server Name Indication extension, to permit choosing a
470 different certificate; tls_privatekey will also be re-expanded. You must
471 still set these options to expand to valid files when $tls_sni is not set.
473 The SMTP Transport has gained the option tls_sni, which will set a hostname
474 for outbound TLS sessions, and set $tls_sni too.
476 A new log_selector, +tls_sni, has been added, to log received SNI values
477 for Exim as a server.
479 8. The existing "accept_8bitmime" option now defaults to true. This means
480 that Exim is deliberately not strictly RFC compliant. We're following
481 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
482 Those who disagree, or know that they are talking to mail servers that,
483 even today, are not 8-bit clean, need to turn off this option.
485 9. Exim can now be started with -bw (with an optional timeout, given as
486 -bw<timespec>). With this, stdin at startup is a socket that is
487 already listening for connections. This has a more modern name of
488 "socket activation", but forcing the activated socket to fd 0. We're
489 interested in adding more support for modern variants.
491 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
492 for numbers indicates multiplication by 1024^3.
494 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
495 gnutls_require_mac & gnutls_require_protocols are no longer supported.
496 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
497 string, documentation for which is at:
498 http://www.gnutls.org/manual/html_node/Priority-Strings.html
500 SNI support has been added to Exim's GnuTLS integration too.
502 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
503 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
505 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
506 is now available. If the contents of the file are valid, then Exim will
507 send that back in response to a TLS status request; this is OCSP Stapling.
508 Exim will not maintain the contents of the file in any way: administrators
509 are responsible for ensuring that it is up-to-date.
511 See "experimental-spec.txt" for more details.
513 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
514 identically to TXT record lookups.
516 14. New expansion variable $tod_epoch_l for higher-precision time.
518 15. New global option tls_dh_max_bits, defaulting to current value of NSS
519 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
520 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
522 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
523 Option can now be a path or an identifier for a standard prime.
524 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
525 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
528 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
529 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
530 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
536 1. New options for the ratelimit ACL condition: /count= and /unique=.
537 The /noupdate option has been replaced by a /readonly option.
539 2. The SMTP transport's protocol option may now be set to "smtps", to
540 use SSL-on-connect outbound.
542 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
543 there is a problem talking to the AV scanner, or the AV scanner running.
545 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
546 and check if the search item is a member of the list. This does not
547 support named lists, but does subject the list part to string expansion.
549 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
550 built, Exim no longer performs string expansion on the second string of
551 the match_* expansion conditions: "match_address", "match_domain",
552 "match_ip" & "match_local_part". Named lists can still be used.
558 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
559 or off in the resolver library.
565 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
566 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
567 libraries. The following global options have been added in support of
568 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
569 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
571 2. The pipe transport now takes a boolean option, "freeze_signal", default
572 false. When true, if the external delivery command exits on a signal then
573 Exim will freeze the message in the queue, instead of generating a bounce.
575 3. Log filenames may now use %M as an escape, instead of %D (still available).
576 The %M pattern expands to yyyymm, providing month-level resolution.
578 4. The $message_linecount variable is now updated for the maildir_tag option,
579 in the same way as $message_size, to reflect the real number of lines,
580 including any header additions or removals from transport.
582 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
583 Exim now selects entries randomly, to better scale in a cluster setup.
589 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
590 the flaw permitted the Exim run-time user to cause root to append to
591 arbitrary files of the attacker's choosing, with the content based
592 on content supplied by the attacker.
594 2. Exim now supports loading some lookup types at run-time, using your
595 platform's dlopen() functionality. This has limited platform support
596 and the intention is not to support every variant, it's limited to
597 dlopen(). This permits the main Exim binary to not be linked against
598 all the libraries needed for all the lookup types.
604 NOTE: this version is not guaranteed backwards-compatible, please read the
605 items below carefully
607 1. A new main configuration option, "openssl_options", is available if Exim
608 is built with SSL support provided by OpenSSL. The option allows
609 administrators to specify OpenSSL options to be used on connections;
610 typically this is to set bug compatibility features which the OpenSSL
611 developers have not enabled by default. There may be security
612 consequences for certain options, so these should not be changed
615 2. A new pipe transport option, "permit_coredumps", may help with problem
616 diagnosis in some scenarios. Note that Exim is typically installed as
617 a setuid binary, which on most OSes will inhibit coredumps by default,
618 so that safety mechanism would have to be overridden for this option to
619 be able to take effect.
621 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
622 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
623 Note that this switches Exim to use a new API ("INSTREAM") and a future
624 release of ClamAV will remove support for the old API ("STREAM").
626 The av_scanner option, when set to "clamd", now takes an optional third
627 part, "local", which causes Exim to pass a filename to ClamAV instead of
628 the file content. This is the same behaviour as when clamd is pointed at
629 a Unix-domain socket. For example:
631 av_scanner = clamd:192.0.2.3 1234:local
633 ClamAV's ExtendedDetectionInfo response format is now handled.
635 4. There is now a -bmalware option, restricted to admin users. This option
636 takes one parameter, a filename, and scans that file with Exim's
637 malware-scanning framework. This is intended purely as a debugging aid
638 to ensure that Exim's scanning is working, not to replace other tools.
639 Note that the ACL framework is not invoked, so if av_scanner references
640 ACL variables without a fallback then this will fail.
642 5. There is a new expansion operator, "reverse_ip", which will reverse IP
643 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
645 ${reverse_ip:192.0.2.4}
647 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
648 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
650 6. There is a new ACL control called "debug", to enable debug logging.
651 This allows selective logging of certain incoming transactions within
652 production environments, with some care. It takes two options, "tag"
653 and "opts"; "tag" is included in the filename of the log and "opts"
654 is used as per the -d<options> command-line option. Examples, which
655 don't all make sense in all contexts:
658 control = debug/tag=.$sender_host_address
659 control = debug/opts=+expand+acl
660 control = debug/tag=.$message_exim_id/opts=+expand
662 7. It has always been implicit in the design and the documentation that
663 "the Exim user" is not root. src/EDITME said that using root was
664 "very strongly discouraged". This is not enough to keep people from
665 shooting themselves in the foot in days when many don't configure Exim
666 themselves but via package build managers. The security consequences of
667 running various bits of network code are severe if there should be bugs in
668 them. As such, the Exim user may no longer be root. If configured
669 statically, Exim will refuse to build. If configured as ref:user then Exim
670 will exit shortly after start-up. If you must shoot yourself in the foot,
671 then henceforth you will have to maintain your own local patches to strip
674 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
675 condition logic to determine truth/failure and will fail to expand many
676 strings, bool_lax{} uses the router condition logic, where most strings
678 Note: bool{00} is false, bool_lax{00} is true.
680 9. Routers now support multiple "condition" tests.
682 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
683 Setting this allows an admin to define which entry in the tcpwrappers
684 config file will be used to control access to the daemon. This option
685 is only available when Exim is built with USE_TCP_WRAPPERS. The
686 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
689 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
690 the Exim run-time user, instead of root.
692 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
693 is forced on. This is mitigated by the new build option
694 TRUSTED_CONFIG_LIST which defines a list of configuration files which
695 are trusted; one per line. If a config file is owned by root and matches
696 a pathname in the list, then it may be invoked by the Exim build-time
697 user without Exim relinquishing root privileges.
699 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
700 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
701 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
702 include the main config. As a transition mechanism, we are temporarily
703 providing a work-around: the new build option WHITELIST_D_MACROS provides
704 a colon-separated list of macro names which may be overridden by the Exim
705 run-time user. The values of these macros are constrained to the regex
706 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
712 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
713 writable, the other to locking of MBX folders (not mbox).
715 2. MySQL stored procedures are now supported.
717 3. The dkim_domain transport option is now a list, not a single string, and
718 messages will be signed for each element in the list (discarding
721 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
722 in the presence of multiple character strings within the RR. Prior to 4.70,
723 only the first string would be returned. The dnsdb lookup now, by default,
724 preserves the pre-4.70 semantics, but also now takes an extended output
725 separator specification. The separator can be followed by a semicolon, to
726 concatenate the individual text strings together with no join character,
727 or by a comma and a second separator character, in which case the text
728 strings within a TXT record are joined on that second character.
729 Administrators are reminded that DNS provides no ordering guarantees
730 between multiple records in an RRset. For example:
732 foo.example. IN TXT "a" "b" "c"
733 foo.example. IN TXT "d" "e" "f"
735 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
736 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
737 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
743 1. Native DKIM support without an external library.
744 (Note that if no action to prevent it is taken, a straight upgrade will
745 result in DKIM verification of all signed incoming emails. See spec
746 for details on conditionally disabling)
748 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
750 3. There is now a bool{} expansion condition which maps certain strings to
751 true/false condition values (most likely of use in conjunction with the
752 and{} expansion operator).
754 4. The $spam_score, $spam_bar and $spam_report variables are now available
757 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
758 options, provided that Exim is invoked by an admin_user.
760 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
761 which increases compatibility with older clients at the cost of decreased
762 security. Don't set this unless you need to support such clients.
764 7. There is a new expansion operator, ${randint:...} which will produce a
765 "random" number less than the supplied integer. This randomness is
766 not guaranteed to be cryptographically strong, but depending upon how
767 Exim was built may be better than the most naive schemes.
769 8. Exim now explicitly ensures that SHA256 is available when linked against
772 9. The transport_filter_timeout option now applies to SMTP transports too.
778 1. Preliminary DKIM support in Experimental.
784 1. The body_linecount and body_zerocount C variables are now exported in the
787 2. When a dnslists lookup succeeds, the key that was looked up is now placed
788 in $dnslist_matched. When the key is an IP address, it is not reversed in
789 this variable (though it is, of course, in the actual lookup). In simple
792 deny dnslists = spamhaus.example
794 the key is also available in another variable (in this case,
795 $sender_host_address). In more complicated cases, however, this is not
796 true. For example, using a data lookup might generate a dnslists lookup
799 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
801 If this condition succeeds, the value in $dnslist_matched might be
802 192.168.6.7 (for example).
804 3. Authenticators now have a client_condition option. When Exim is running as
805 a client, it skips an authenticator whose client_condition expansion yields
806 "0", "no", or "false". This can be used, for example, to skip plain text
807 authenticators when the connection is not encrypted by a setting such as:
809 client_condition = ${if !eq{$tls_cipher}{}}
811 Note that the 4.67 documentation states that $tls_cipher contains the
812 cipher used for incoming messages. In fact, during SMTP delivery, it
813 contains the cipher used for the delivery. The same is true for
816 4. There is now a -Mvc <message-id> option, which outputs a copy of the
817 message to the standard output, in RFC 2822 format. The option can be used
818 only by an admin user.
820 5. There is now a /noupdate option for the ratelimit ACL condition. It
821 computes the rate and checks the limit as normal, but it does not update
822 the saved data. This means that, in relevant ACLs, it is possible to lookup
823 the existence of a specified (or auto-generated) ratelimit key without
824 incrementing the ratelimit counter for that key.
826 In order for this to be useful, another ACL entry must set the rate
827 for the same key somewhere (otherwise it will always be zero).
832 # Read the rate; if it doesn't exist or is below the maximum
834 deny ratelimit = 100 / 5m / strict / noupdate
835 log_message = RATE: $sender_rate / $sender_rate_period \
836 (max $sender_rate_limit)
838 [... some other logic and tests...]
840 warn ratelimit = 100 / 5m / strict / per_cmd
841 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
842 (max $sender_rate_limit)
843 condition = ${if le{$sender_rate}{$sender_rate_limit}}
847 6. The variable $max_received_linelength contains the number of bytes in the
848 longest line that was received as part of the message, not counting the
849 line termination character(s).
851 7. Host lists can now include +ignore_defer and +include_defer, analagous to
852 +ignore_unknown and +include_unknown. These options should be used with
853 care, probably only in non-critical host lists such as whitelists.
855 8. There's a new option called queue_only_load_latch, which defaults true.
856 If set false when queue_only_load is greater than zero, Exim re-evaluates
857 the load for each incoming message in an SMTP session. Otherwise, once one
858 message is queued, the remainder are also.
860 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
861 cases when an SMTP session ends without sending QUIT. However, when Exim
862 itself is is bad trouble, such as being unable to write to its log files,
863 this ACL is not run, because it might try to do things (such as write to
864 log files) that make the situation even worse.
866 Like the QUIT ACL, this new ACL is provided to make it possible to gather
867 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
868 modifier is forbidden in this ACL.
870 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
871 to a string that indicates the reason for the termination of the SMTP
872 connection. The possible values are:
874 acl-drop Another ACL issued a "drop" command
875 bad-commands Too many unknown or non-mail commands
876 command-timeout Timeout while reading SMTP commands
877 connection-lost The SMTP connection has been lost
878 data-timeout Timeout while reading message data
879 local-scan-error The local_scan() function crashed
880 local-scan-timeout The local_scan() function timed out
881 signal-exit SIGTERM or SIGINT
882 synchronization-error SMTP synchronization error
883 tls-failed TLS failed to start
885 In most cases when an SMTP connection is closed without having received
886 QUIT, Exim sends an SMTP response message before actually closing the
887 connection. With the exception of acl-drop, the default message can be
888 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
889 "drop" verb in another ACL, it is the message from the other ACL that is
892 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
893 servers with individual queries. This is done by starting the query with
894 "servers=x:y:z;", where each item in the list may take one of two forms:
896 (1) If it is just a host name, the appropriate global option (mysql_servers
897 or pgsql_servers) is searched for a host of the same name, and the
898 remaining parameters (database, user, password) are taken from there.
900 (2) If it contains any slashes, it is taken as a complete parameter set.
902 The list of servers is used in exactly the same was as the global list.
903 Once a connection to a server has happened and a query has been
904 successfully executed, processing of the lookup ceases.
906 This feature is intended for use in master/slave situations where updates
907 are occurring, and one wants to update a master rather than a slave. If the
908 masters are in the list for reading, you might have:
910 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
912 In an updating lookup, you could then write
914 ${lookup mysql{servers=master; UPDATE ...}
916 If, on the other hand, the master is not to be used for reading lookups:
918 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
920 you can still update the master by
922 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
924 11. The message_body_newlines option (default FALSE, for backwards
925 compatibility) can be used to control whether newlines are present in
926 $message_body and $message_body_end. If it is FALSE, they are replaced by
933 1. There is a new log selector called smtp_no_mail, which is not included in
934 the default setting. When it is set, a line is written to the main log
935 whenever an accepted SMTP connection terminates without having issued a
938 2. When an item in a dnslists list is followed by = and & and a list of IP
939 addresses, the behaviour was not clear when the lookup returned more than
940 one IP address. This has been solved by the addition of == and =& for "all"
941 rather than the default "any" matching.
943 3. Up till now, the only control over which cipher suites GnuTLS uses has been
944 for the cipher algorithms. New options have been added to allow some of the
945 other parameters to be varied.
947 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
948 set, Exim compiles a runtime option called disable_fsync.
950 5. There is a new variable called $smtp_count_at_connection_start.
952 6. There's a new control called no_pipelining.
954 7. There are two new variables called $sending_ip_address and $sending_port.
955 These are set whenever an SMTP connection to another host has been set up.
957 8. The expansion of the helo_data option in the smtp transport now happens
958 after the connection to the server has been made.
960 9. There is a new expansion operator ${rfc2047d: that decodes strings that
961 are encoded as per RFC 2047.
963 10. There is a new log selector called "pid", which causes the current process
964 id to be added to every log line, in square brackets, immediately after the
967 11. Exim has been modified so that it flushes SMTP output before implementing
968 a delay in an ACL. It also flushes the output before performing a callout,
969 as this can take a substantial time. These behaviours can be disabled by
970 obeying control = no_delay_flush or control = no_callout_flush,
971 respectively, at some earlier stage of the connection.
973 12. There are two new expansion conditions that iterate over a list. They are
974 called forany and forall.
976 13. There's a new global option called dsn_from that can be used to vary the
977 contents of From: lines in bounces and other automatically generated
978 messages ("delivery status notifications" - hence the name of the option).
980 14. The smtp transport has a new option called hosts_avoid_pipelining.
982 15. By default, exigrep does case-insensitive matches. There is now a -I option
983 that makes it case-sensitive.
985 16. A number of new features ("addresses", "map", "filter", and "reduce") have
986 been added to string expansions to make it easier to process lists of
987 items, typically addresses.
989 17. There's a new ACL modifier called "continue". It does nothing of itself,
990 and processing of the ACL always continues with the next condition or
991 modifier. It is provided so that the side effects of expanding its argument
994 18. It is now possible to use newline and other control characters (those with
995 values less than 32, plus DEL) as separators in lists.
997 19. The exigrep utility now has a -v option, which inverts the matching
1000 20. The host_find_failed option in the manualroute router can now be set to
1007 No new features were added to 4.66.
1013 No new features were added to 4.65.
1019 1. ACL variables can now be given arbitrary names, as long as they start with
1020 "acl_c" or "acl_m" (for connection variables and message variables), are at
1021 least six characters long, with the sixth character being either a digit or
1024 2. There is a new ACL modifier called log_reject_target. It makes it possible
1025 to specify which logs are used for messages about ACL rejections.
1027 3. There is a new authenticator called "dovecot". This is an interface to the
1028 authentication facility of the Dovecot POP/IMAP server, which can support a
1029 number of authentication methods.
1031 4. The variable $message_headers_raw provides a concatenation of all the
1032 messages's headers without any decoding. This is in contrast to
1033 $message_headers, which does RFC2047 decoding on the header contents.
1035 5. In a DNS black list, if two domain names, comma-separated, are given, the
1036 second is used first to do an initial check, making use of any IP value
1037 restrictions that are set. If there is a match, the first domain is used,
1038 without any IP value restrictions, to get the TXT record.
1040 6. All authenticators now have a server_condition option.
1042 7. There is a new command-line option called -Mset. It is useful only in
1043 conjunction with -be (that is, when testing string expansions). It must be
1044 followed by a message id; Exim loads the given message from its spool
1045 before doing the expansions.
1047 8. Another similar new command-line option is called -bem. It operates like
1048 -be except that it must be followed by the name of a file that contains a
1051 9. When an address is delayed because of a 4xx response to a RCPT command, it
1052 is now the combination of sender and recipient that is delayed in
1053 subsequent queue runs until its retry time is reached.
1055 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1056 shift, have been added to the eval: and eval10: expansion items.
1058 11. The variables $interface_address and $interface_port have been renamed
1059 as $received_ip_address and $received_port, to make it clear that they
1060 relate to message reception rather than delivery. (The old names remain
1061 available for compatibility.)
1063 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1064 to vary the message that is sent when an SMTP command is accepted.
1070 1. There is a new Boolean option called filter_prepend_home for the redirect
1073 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1074 start of receiving a non-SMTP message, before any of the message has been
1077 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1078 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1079 start of the message for an SMTP error code.
1081 4. There is a new parameter for LDAP lookups called "referrals", which takes
1082 one of the settings "follow" (the default) or "nofollow".
1084 5. Version 20070721.2 of exipick now included, offering these new options:
1086 After all other sorting options have bee processed, reverse order
1087 before displaying messages (-R is synonym).
1089 Randomize order of matching messages before displaying.
1091 Instead of displaying the matching messages, display the sum
1093 --sort <variable>[,<variable>...]
1094 Before displaying matching messages, sort the messages according to
1095 each messages value for each variable.
1097 Negate the value for every test (returns inverse output from the
1098 same criteria without --not).
1104 1. The ${readsocket expansion item now supports Internet domain sockets as well
1105 as Unix domain sockets. If the first argument begins "inet:", it must be of
1106 the form "inet:host:port". The port is mandatory; it may be a number or the
1107 name of a TCP port in /etc/services. The host may be a name, or it may be an
1108 IP address. An ip address may optionally be enclosed in square brackets.
1109 This is best for IPv6 addresses. For example:
1111 ${readsocket{inet:[::1]:1234}{<request data>}...
1113 Only a single host name may be given, but if looking it up yield more than
1114 one IP address, they are each tried in turn until a connection is made. Once
1115 a connection has been made, the behaviour is as for ${readsocket with a Unix
1118 2. If a redirect router sets up file or pipe deliveries for more than one
1119 incoming address, and the relevant transport has batch_max set greater than
1120 one, a batch delivery now occurs.
1122 3. The appendfile transport has a new option called maildirfolder_create_regex.
1123 Its value is a regular expression. For a maildir delivery, this is matched
1124 against the maildir directory; if it matches, Exim ensures that a
1125 maildirfolder file is created alongside the new, cur, and tmp directories.
1131 The documentation is up-to-date for the 4.61 release. Major new features since
1132 the 4.60 release are:
1134 . An option called disable_ipv6, to disable the use of IPv6 completely.
1136 . An increase in the number of ACL variables to 20 of each type.
1138 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1139 $2, $3, (though those are still set) because the numeric variables get used
1140 for other things in complicated expansions.
1142 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1144 . It is possible to use setclassresources() on some BSD OS to control the
1145 resources used in pipe deliveries.
1147 . A new ACL modifier called add_header, which can be used with any verb.
1149 . More errors are detectable in retry rules.
1151 There are a number of other additions too.
1157 The documentation is up-to-date for the 4.60 release. Major new features since
1158 the 4.50 release are:
1160 . Support for SQLite.
1162 . Support for IGNOREQUOTA in LMTP.
1164 . Extensions to the "submission mode" features.
1166 . Support for Client SMTP Authorization (CSA).
1168 . Support for ratelimiting hosts and users.
1170 . New expansion items to help with the BATV "prvs" scheme.
1172 . A "match_ip" condition, that matches an IP address against a list.
1174 There are many more minor changes.
git://git.exim.org / users / jgh / exim.git / blob