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. Dual-certificate stacks on servers now support OCSP stapling, under GnuTLS
13 version 3.5.6 or later.
15 2. DANE is now supported under GnuTLS version 3.0.0 or later (adding to the
16 previous OpenSSL implementation, but still Experimental).
22 1. PKG_CONFIG_PATH can now be set in Local/Makefile;
23 wildcards will be expanded, values are collapsed.
25 2. The ${readsocket } expansion now takes an option to not shutdown the
26 connection after sending the query string. The default remains to do so.
28 3. An smtp transport option "hosts_noproxy_tls" to control whether multiple
29 deliveries on a single TCP connection can maintain a TLS connection
30 open. By default disabled for all hosts, doing so saves the cost of
31 making new TLS sessions, at the cost of having to proxy the data via
32 another process. Logging is also affected.
34 4. A malware connection type for the FPSCAND protocol.
36 5. An option for recipient verify callouts to hold the connection open for
37 further recipients and for delivery.
39 6. The reproducible build $SOURCE_DATE_EPOCH environment variable is now
42 7. Optionally, an alternate format for spool data-files which matches the
43 wire format - meaning more efficient reception and transmission (at the
44 cost of difficulty with standard Unix tools). Only used for messages
45 received using the ESMTP CHUNKING option, and when a new main-section
46 option "spool_wireformat" (false by default) is set.
48 8. New main configuration option "commandline_checks_require_admin" to
49 restrict who can use various introspection options.
51 9. New option modifier "no_check" for quota and quota_filecount
54 10. Variable $smtp_command_history returning a comma-sep list of recent
57 11. Millisecond timetamps in logs, on log_selector "millisec". Also affects
58 log elements QT, DT and D, and timstamps in debug output.
60 12. TCP Fast Open logging. As a server, logs when the SMTP banner was sent
61 while still in SYN_RECV state; as a client logs when the connection
62 is opened with a TFO cookie.
64 13. DKIM support for multiple signing, by domain and/or key-selector.
65 DKIM support for multiple hashes, and for alternate-identity tags.
66 Builtin macro with default list of signed headers.
67 Better syntax for specifying oversigning.
68 The DKIM ACL can override verification status, and status is visible in
71 14. Exipick understands -C|--config for an alternative Exim
74 15. TCP Fast Open used, with data-on-SYN, for client SMTP via SOCKS5 proxy,
75 for ${readsocket } expansions, and for ClamAV.
77 16. The "-be" expansion test mode now supports macros. Macros are expanded
78 in test lines, and new macros can be defined.
80 17. Support for server-side dual-certificate-stacks (eg. RSA + ECDSA).
86 1. Allow relative config file names for ".include"
88 2. A main-section config option "debug_store" to control the checks on
89 variable locations during store-reset. Normally false but can be enabled
90 when a memory corrution issue is suspected on a production system.
96 1. The new perl_taintmode option allows to run the embedded perl
97 interpreter in taint mode.
99 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
101 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
104 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
105 N can be 224, 256 (default), 384, 512.
106 With GnuTLS 3.5.0 or later, only.
108 5. Facility for named queues: A command-line argument can specify
109 the queue name for a queue operation, and an ACL modifier can set
110 the queue to be used for a message. A $queue_name variable gives
113 6. New expansion operators base32/base32d.
115 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
116 performance increase and network load decrease. Main config option
117 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
120 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
122 9. Expansion operator escape8bit, like escape but not touching newline etc..
124 10. Feature macros, generated from compile options. All start with "_HAVE_"
125 and go on with some roughly recognisable name. Driver macros, for
126 router, transport and authentication drivers; names starting with "_DRIVER_".
127 Option macros, for each configuration-file option; all start with "_OPT_".
128 Use the "-bP macros" command-line option to see what is present.
130 11. Integer values for options can take a "G" multiplier.
132 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
133 returns from the target back to the initiator, rather than spooling the
136 13. New built-in constants available for tls_dhparam and default changed.
138 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
139 out copies of the message spool files for use by 3rd-party scanners.
141 15. A new option on the smtp transport, hosts_try_fastopen. If the system
142 supports it (on Linux it must be enabled in the kernel by the sysadmin)
143 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
144 but it permits a peer that also supports the facility to send its SMTP
145 banner immediately after the SYN,ACK segment rather then waiting for
146 another ACK - so saving up to one roundtrip time. Because it requires
147 previous communication with the peer (we save a cookie from it) this
148 will only become active on frequently-contacted destinations.
150 16. A new syslog_pid option to suppress PID duplication in syslog lines.
156 1. The ACL conditions regex and mime_regex now capture substrings
157 into numeric variables $regex1 to 9, like the "match" expansion condition.
159 2. New $callout_address variable records the address used for a spam=,
160 malware= or verify= callout.
162 3. Transports now take a "max_parallel" option, to limit concurrency.
164 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
165 The latter expands to a 8-element colon-sep set of hex digits including
166 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
167 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
168 The former operator strips leading zeroes and collapses the longest
169 set of 0-groups to a double-colon.
171 5. New "-bP config" support, to dump the effective configuration.
173 6. New $dkim_key_length variable.
175 7. New base64d and base64 expansion items (the existing str2b64 being a
176 synonym of the latter). Add support in base64 for certificates.
178 8. New main configuration option "bounce_return_linesize_limit" to
179 avoid oversize bodies in bounces. The default value matches RFC
182 9. New $initial_cwd expansion variable.
188 1. Support for using the system standard CA bundle.
190 2. New expansion items $config_file, $config_dir, containing the file
191 and directory name of the main configuration file. Also $exim_version.
193 3. New "malware=" support for Avast.
195 4. New "spam=" variant option for Rspamd.
197 5. Assorted options on malware= and spam= scanners.
199 6. A command-line option to write a comment into the logfile.
201 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
202 be configured to make connections via socks5 proxies.
204 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
205 the transmission of UTF-8 envelope addresses.
207 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
208 used encoding of Maildir folder names.
210 10. A logging option for slow DNS lookups.
212 11. New ${env {<variable>}} expansion.
214 12. A non-SMTP authenticator using information from TLS client certificates.
216 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
217 Patch originally by Wolfgang Breyha.
219 14. Main option "dns_trust_aa" for trusting your local nameserver at the
220 same level as DNSSEC.
226 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
227 DANE SMTP draft to assess a secure chain of trust of the certificate
228 used to establish the TLS connection based on a TLSA record in the
229 domain of the sender.
231 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
232 and several new events have been created. The reason is because it has
233 been expanded beyond just firing events during the transport phase. Any
234 existing TPDA transport options will have to be rewritten to use a new
235 $event_name expansion variable in a condition. Refer to the
236 experimental-spec.txt for details and examples.
238 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
239 server certs used for TLS match the result of the MX lookup. It does
240 not use the same mechanism as DANE.
250 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
251 configured to expect an initial header from a proxy that will make the
252 actual external source IP:host be used in exim instead of the IP of the
253 proxy that is connecting to it.
255 2. New verify option header_names_ascii, which will check to make sure
256 there are no non-ASCII characters in header names. Exim itself handles
257 those non-ASCII characters, but downstream apps may not, so Exim can
258 detect and reject if those characters are present.
260 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
261 codepoints with valid ones.
263 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
264 command line and matching a regex against the return data for trigger
265 and a second regex to extract malware_name. The mail spoolfile name can
266 be included in the command line.
268 5. The smtp transport now supports options "tls_verify_hosts" and
269 "tls_try_verify_hosts". If either is set the certificate verification
270 is split from the encryption operation. The default remains that a failed
271 verification cancels the encryption.
273 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
274 lookup can now set a list of servers to use that is different from the
277 7. New command-line option -C for exiqgrep to specify alternate exim.conf
278 file when searching the queue.
280 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
282 9. Support for DNSSEC on outbound connections.
284 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
285 "certextract" to extract fields from them. Hash operators md5 and sha1
286 work over them for generating fingerprints, and a new sha256 operator
289 11. PRDR is now supported dy default.
291 12. OCSP stapling is now supported by default.
293 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
294 Delivery Status Notification messages in MIME format, and negotiate
295 DSN features per RFC 3461.
301 1. New command-line option -bI:sieve will list all supported sieve extensions
302 of this Exim build on standard output, one per line.
303 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
304 query this to establish the correct list to include in the protocol's
305 SIEVE capability line.
307 2. If the -n option is combined with the -bP option, then the name of an
308 emitted option is not output, only the value (if visible to you).
309 For instance, "exim -n -bP pid_file_path" should just emit a pathname
310 followed by a newline, and no other text.
312 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
313 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
314 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
315 acceptable for security. (Option accepted but ignored if using OpenSSL).
316 Defaults to 1024, the old value. May be lowered only to 512, or raised as
317 far as you like. Raising this may hinder TLS interoperability with other
318 sites and is not currently recommended. Lowering this will permit you to
319 establish a TLS session which is not as secure as you might like.
321 Unless you really know what you are doing, leave it alone.
323 4. If not built with DISABLE_DNSSEC, Exim now has the main option
324 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
325 to send the DO flag to your recursive resolver. If you have a recursive
326 resolver, which can set the Authenticated Data (AD) flag in results, Exim
327 can now detect this. Exim does not perform validation itself, instead
328 relying upon a trusted path to the resolver.
330 Current status: work-in-progress; $sender_host_dnssec variable added.
332 5. DSCP support for outbound connections: on a transport using the smtp driver,
333 set "dscp = ef", for instance, to cause the connections to have the relevant
334 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
336 Similarly for inbound connections, there is a new control modifier, dscp,
337 so "warn control = dscp/ef" in the connect ACL, or after authentication.
339 Supported values depend upon system libraries. "exim -bI:dscp" to list the
340 ones Exim knows of. You can also set a raw number 0..0x3F.
342 6. The -G command-line flag is no longer ignored; it is now equivalent to an
343 ACL setting "control = suppress_local_fixups". The -L command-line flag
344 is now accepted and forces use of syslog, with the provided tag as the
345 process name. A few other flags used by Sendmail are now accepted and
348 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
349 ACL modifier; works for single-recipient mails which are received on and
350 deliverable via SMTP. Using the connection made for a recipient verify,
351 if requested before the verify, or a new one made for the purpose while
352 the inbound connection is still active. The bulk of the mail item is copied
353 direct from the inbound socket to the outbound (as well as the spool file).
354 When the source notifies the end of data, the data acceptance by the destination
355 is negotiated before the acceptance is sent to the source. If the destination
356 does not accept the mail item, for example due to content-scanning, the item
357 is not accepted from the source and therefore there is no need to generate
358 a bounce mail. This is of benefit when providing a secondary-MX service.
359 The downside is that delays are under the control of the ultimate destination
362 The Received-by: header on items delivered by cutthrough is generated
363 early in reception rather than at the end; this will affect any timestamp
364 included. The log line showing delivery is recorded before that showing
365 reception; it uses a new ">>" tag instead of "=>".
367 To support the feature, verify-callout connections can now use ESMTP and TLS.
368 The usual smtp transport options are honoured, plus a (new, default everything)
369 hosts_verify_avoid_tls.
371 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
372 for specific access to the information for each connection. The old names
373 are present for now but deprecated.
375 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
377 8. New expansion operators ${listnamed:name} to get the content of a named list
378 and ${listcount:string} to count the items in a list.
380 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
381 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
382 modules. For some situations this is desirable, but we expect admin in
383 those situations to know they want the feature. More commonly, it means
384 that GUI user modules get loaded and are broken by the setuid Exim being
385 unable to access files specified in environment variables and passed
386 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
387 unless this new option is set.
389 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
390 so have also added a build option which can be used to build Exim with GnuTLS
391 but without trying to use any kind of PKCS11 support. Uncomment this in the
394 AVOID_GNUTLS_PKCS11=yes
396 10. The "acl = name" condition on an ACL now supports optional arguments.
397 New expansion item "${acl {name}{arg}...}" and expansion condition
398 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
399 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
400 Variable $acl_narg contains the number of arguments. If the ACL sets
401 a "message =" value this becomes the result of the expansion item,
402 or the value of $value for the expansion condition. If the ACL returns
403 accept the expansion condition is true; if reject, false. A defer
404 return results in a forced fail.
406 11. Routers and transports can now have multiple headers_add and headers_remove
407 option lines. The concatenated list is used.
409 12. New ACL modifier "remove_header" can remove headers before message gets
410 handled by routers/transports.
412 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
413 "aaaa" and "a" lookups is done and the full set of results returned.
415 14. New expansion variable $headers_added with content from ACL add_header
416 modifier (but not yet added to message).
418 15. New 8bitmime status logging option for received messages. Log field "M8S".
420 16. New authenticated_sender logging option, adding to log field "A".
422 17. New expansion variables $router_name and $transport_name. Useful
423 particularly for debug_print as -bt command-line option does not
424 require privilege whereas -d does.
426 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
427 proposed extension to SMTP from Eric Hall.
429 19. The pipe transport has gained the force_command option, to allow
430 decorating commands from user .forward pipe aliases with prefix
431 wrappers, for instance.
433 20. Callout connections can now AUTH; the same controls as normal delivery
436 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
437 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
438 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
439 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
440 dmarc_status. It adds new control flags dmarc_disable_verify and
441 dmarc_enable_forensic. The default for the dmarc_tld_file option is
442 "/etc/exim/opendmarc.tlds" and can be changed via EDITME.
444 22. Add expansion variable $authenticated_fail_id, which is the username
445 provided to the authentication method which failed. It is available
446 for use in subsequent ACL processing (typically quit or notquit ACLs).
448 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
451 24. New ${hexquote:..string..} expansion operator converts non-printable
452 characters in the string to \xNN form.
454 25. Experimental TPDA (Transport Post Delivery Action) function added.
455 Patch provided by Axel Rau.
457 26. Experimental Redis lookup added. Patch provided by Warren Baker.
463 1. New authenticator driver, "gsasl". Server-only (at present).
464 This is a SASL interface, licensed under GPL, which can be found at
465 http://www.gnu.org/software/gsasl/.
466 This system does not provide sources of data for authentication, so
467 careful use needs to be made of the conditions in Exim.
469 2. New authenticator driver, "heimdal_gssapi". Server-only.
470 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
471 is no longer honoured for setuid programs by Heimdal. Use the
472 "server_keytab" option to point to the keytab.
474 3. The "pkg-config" system can now be used when building Exim to reference
475 cflags and library information for lookups and authenticators, rather
476 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
477 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
478 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
480 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
481 find the headers and libraries for PCRE.
483 4. New expansion variable $tls_bits.
485 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
486 be joined together with ASCII NUL characters to construct the key to pass
487 into the DBM library. Can be used with gsasl to access sasldb2 files as
490 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
492 Avoid release 1.0.1a if you can. Note that the default value of
493 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
494 increased susceptibility to attack. This may still have interoperability
495 implications for very old clients (see version 4.31 change 37) but
496 administrators can choose to make the trade-off themselves and restore
497 compatibility at the cost of session security.
499 7. Use of the new expansion variable $tls_sni in the main configuration option
500 tls_certificate will cause Exim to re-expand the option, if the client
501 sends the TLS Server Name Indication extension, to permit choosing a
502 different certificate; tls_privatekey will also be re-expanded. You must
503 still set these options to expand to valid files when $tls_sni is not set.
505 The SMTP Transport has gained the option tls_sni, which will set a hostname
506 for outbound TLS sessions, and set $tls_sni too.
508 A new log_selector, +tls_sni, has been added, to log received SNI values
509 for Exim as a server.
511 8. The existing "accept_8bitmime" option now defaults to true. This means
512 that Exim is deliberately not strictly RFC compliant. We're following
513 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
514 Those who disagree, or know that they are talking to mail servers that,
515 even today, are not 8-bit clean, need to turn off this option.
517 9. Exim can now be started with -bw (with an optional timeout, given as
518 -bw<timespec>). With this, stdin at startup is a socket that is
519 already listening for connections. This has a more modern name of
520 "socket activation", but forcing the activated socket to fd 0. We're
521 interested in adding more support for modern variants.
523 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
524 for numbers indicates multiplication by 1024^3.
526 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
527 gnutls_require_mac & gnutls_require_protocols are no longer supported.
528 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
529 string, documentation for which is at:
530 http://www.gnutls.org/manual/html_node/Priority-Strings.html
532 SNI support has been added to Exim's GnuTLS integration too.
534 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
535 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
537 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
538 is now available. If the contents of the file are valid, then Exim will
539 send that back in response to a TLS status request; this is OCSP Stapling.
540 Exim will not maintain the contents of the file in any way: administrators
541 are responsible for ensuring that it is up-to-date.
543 See "experimental-spec.txt" for more details.
545 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
546 identically to TXT record lookups.
548 14. New expansion variable $tod_epoch_l for higher-precision time.
550 15. New global option tls_dh_max_bits, defaulting to current value of NSS
551 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
552 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
554 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
555 Option can now be a path or an identifier for a standard prime.
556 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
557 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
560 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
561 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
562 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
568 1. New options for the ratelimit ACL condition: /count= and /unique=.
569 The /noupdate option has been replaced by a /readonly option.
571 2. The SMTP transport's protocol option may now be set to "smtps", to
572 use SSL-on-connect outbound.
574 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
575 there is a problem talking to the AV scanner, or the AV scanner running.
577 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
578 and check if the search item is a member of the list. This does not
579 support named lists, but does subject the list part to string expansion.
581 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
582 built, Exim no longer performs string expansion on the second string of
583 the match_* expansion conditions: "match_address", "match_domain",
584 "match_ip" & "match_local_part". Named lists can still be used.
590 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
591 or off in the resolver library.
597 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
598 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
599 libraries. The following global options have been added in support of
600 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
601 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
603 2. The pipe transport now takes a boolean option, "freeze_signal", default
604 false. When true, if the external delivery command exits on a signal then
605 Exim will freeze the message in the queue, instead of generating a bounce.
607 3. Log filenames may now use %M as an escape, instead of %D (still available).
608 The %M pattern expands to yyyymm, providing month-level resolution.
610 4. The $message_linecount variable is now updated for the maildir_tag option,
611 in the same way as $message_size, to reflect the real number of lines,
612 including any header additions or removals from transport.
614 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
615 Exim now selects entries randomly, to better scale in a cluster setup.
621 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
622 the flaw permitted the Exim run-time user to cause root to append to
623 arbitrary files of the attacker's choosing, with the content based
624 on content supplied by the attacker.
626 2. Exim now supports loading some lookup types at run-time, using your
627 platform's dlopen() functionality. This has limited platform support
628 and the intention is not to support every variant, it's limited to
629 dlopen(). This permits the main Exim binary to not be linked against
630 all the libraries needed for all the lookup types.
636 NOTE: this version is not guaranteed backwards-compatible, please read the
637 items below carefully
639 1. A new main configuration option, "openssl_options", is available if Exim
640 is built with SSL support provided by OpenSSL. The option allows
641 administrators to specify OpenSSL options to be used on connections;
642 typically this is to set bug compatibility features which the OpenSSL
643 developers have not enabled by default. There may be security
644 consequences for certain options, so these should not be changed
647 2. A new pipe transport option, "permit_coredumps", may help with problem
648 diagnosis in some scenarios. Note that Exim is typically installed as
649 a setuid binary, which on most OSes will inhibit coredumps by default,
650 so that safety mechanism would have to be overridden for this option to
651 be able to take effect.
653 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
654 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
655 Note that this switches Exim to use a new API ("INSTREAM") and a future
656 release of ClamAV will remove support for the old API ("STREAM").
658 The av_scanner option, when set to "clamd", now takes an optional third
659 part, "local", which causes Exim to pass a filename to ClamAV instead of
660 the file content. This is the same behaviour as when clamd is pointed at
661 a Unix-domain socket. For example:
663 av_scanner = clamd:192.0.2.3 1234:local
665 ClamAV's ExtendedDetectionInfo response format is now handled.
667 4. There is now a -bmalware option, restricted to admin users. This option
668 takes one parameter, a filename, and scans that file with Exim's
669 malware-scanning framework. This is intended purely as a debugging aid
670 to ensure that Exim's scanning is working, not to replace other tools.
671 Note that the ACL framework is not invoked, so if av_scanner references
672 ACL variables without a fallback then this will fail.
674 5. There is a new expansion operator, "reverse_ip", which will reverse IP
675 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
677 ${reverse_ip:192.0.2.4}
679 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
680 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
682 6. There is a new ACL control called "debug", to enable debug logging.
683 This allows selective logging of certain incoming transactions within
684 production environments, with some care. It takes two options, "tag"
685 and "opts"; "tag" is included in the filename of the log and "opts"
686 is used as per the -d<options> command-line option. Examples, which
687 don't all make sense in all contexts:
690 control = debug/tag=.$sender_host_address
691 control = debug/opts=+expand+acl
692 control = debug/tag=.$message_exim_id/opts=+expand
694 7. It has always been implicit in the design and the documentation that
695 "the Exim user" is not root. src/EDITME said that using root was
696 "very strongly discouraged". This is not enough to keep people from
697 shooting themselves in the foot in days when many don't configure Exim
698 themselves but via package build managers. The security consequences of
699 running various bits of network code are severe if there should be bugs in
700 them. As such, the Exim user may no longer be root. If configured
701 statically, Exim will refuse to build. If configured as ref:user then Exim
702 will exit shortly after start-up. If you must shoot yourself in the foot,
703 then henceforth you will have to maintain your own local patches to strip
706 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
707 condition logic to determine truth/failure and will fail to expand many
708 strings, bool_lax{} uses the router condition logic, where most strings
710 Note: bool{00} is false, bool_lax{00} is true.
712 9. Routers now support multiple "condition" tests.
714 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
715 Setting this allows an admin to define which entry in the tcpwrappers
716 config file will be used to control access to the daemon. This option
717 is only available when Exim is built with USE_TCP_WRAPPERS. The
718 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
721 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
722 the Exim run-time user, instead of root.
724 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
725 is forced on. This is mitigated by the new build option
726 TRUSTED_CONFIG_LIST which defines a list of configuration files which
727 are trusted; one per line. If a config file is owned by root and matches
728 a pathname in the list, then it may be invoked by the Exim build-time
729 user without Exim relinquishing root privileges.
731 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
732 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
733 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
734 include the main config. As a transition mechanism, we are temporarily
735 providing a work-around: the new build option WHITELIST_D_MACROS provides
736 a colon-separated list of macro names which may be overridden by the Exim
737 run-time user. The values of these macros are constrained to the regex
738 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
744 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
745 writable, the other to locking of MBX folders (not mbox).
747 2. MySQL stored procedures are now supported.
749 3. The dkim_domain transport option is now a list, not a single string, and
750 messages will be signed for each element in the list (discarding
753 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
754 in the presence of multiple character strings within the RR. Prior to 4.70,
755 only the first string would be returned. The dnsdb lookup now, by default,
756 preserves the pre-4.70 semantics, but also now takes an extended output
757 separator specification. The separator can be followed by a semicolon, to
758 concatenate the individual text strings together with no join character,
759 or by a comma and a second separator character, in which case the text
760 strings within a TXT record are joined on that second character.
761 Administrators are reminded that DNS provides no ordering guarantees
762 between multiple records in an RRset. For example:
764 foo.example. IN TXT "a" "b" "c"
765 foo.example. IN TXT "d" "e" "f"
767 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
768 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
769 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
775 1. Native DKIM support without an external library.
776 (Note that if no action to prevent it is taken, a straight upgrade will
777 result in DKIM verification of all signed incoming emails. See spec
778 for details on conditionally disabling)
780 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
782 3. There is now a bool{} expansion condition which maps certain strings to
783 true/false condition values (most likely of use in conjunction with the
784 and{} expansion operator).
786 4. The $spam_score, $spam_bar and $spam_report variables are now available
789 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
790 options, provided that Exim is invoked by an admin_user.
792 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
793 which increases compatibility with older clients at the cost of decreased
794 security. Don't set this unless you need to support such clients.
796 7. There is a new expansion operator, ${randint:...} which will produce a
797 "random" number less than the supplied integer. This randomness is
798 not guaranteed to be cryptographically strong, but depending upon how
799 Exim was built may be better than the most naive schemes.
801 8. Exim now explicitly ensures that SHA256 is available when linked against
804 9. The transport_filter_timeout option now applies to SMTP transports too.
810 1. Preliminary DKIM support in Experimental.
816 1. The body_linecount and body_zerocount C variables are now exported in the
819 2. When a dnslists lookup succeeds, the key that was looked up is now placed
820 in $dnslist_matched. When the key is an IP address, it is not reversed in
821 this variable (though it is, of course, in the actual lookup). In simple
824 deny dnslists = spamhaus.example
826 the key is also available in another variable (in this case,
827 $sender_host_address). In more complicated cases, however, this is not
828 true. For example, using a data lookup might generate a dnslists lookup
831 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
833 If this condition succeeds, the value in $dnslist_matched might be
834 192.168.6.7 (for example).
836 3. Authenticators now have a client_condition option. When Exim is running as
837 a client, it skips an authenticator whose client_condition expansion yields
838 "0", "no", or "false". This can be used, for example, to skip plain text
839 authenticators when the connection is not encrypted by a setting such as:
841 client_condition = ${if !eq{$tls_cipher}{}}
843 Note that the 4.67 documentation states that $tls_cipher contains the
844 cipher used for incoming messages. In fact, during SMTP delivery, it
845 contains the cipher used for the delivery. The same is true for
848 4. There is now a -Mvc <message-id> option, which outputs a copy of the
849 message to the standard output, in RFC 2822 format. The option can be used
850 only by an admin user.
852 5. There is now a /noupdate option for the ratelimit ACL condition. It
853 computes the rate and checks the limit as normal, but it does not update
854 the saved data. This means that, in relevant ACLs, it is possible to lookup
855 the existence of a specified (or auto-generated) ratelimit key without
856 incrementing the ratelimit counter for that key.
858 In order for this to be useful, another ACL entry must set the rate
859 for the same key somewhere (otherwise it will always be zero).
864 # Read the rate; if it doesn't exist or is below the maximum
866 deny ratelimit = 100 / 5m / strict / noupdate
867 log_message = RATE: $sender_rate / $sender_rate_period \
868 (max $sender_rate_limit)
870 [... some other logic and tests...]
872 warn ratelimit = 100 / 5m / strict / per_cmd
873 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
874 (max $sender_rate_limit)
875 condition = ${if le{$sender_rate}{$sender_rate_limit}}
879 6. The variable $max_received_linelength contains the number of bytes in the
880 longest line that was received as part of the message, not counting the
881 line termination character(s).
883 7. Host lists can now include +ignore_defer and +include_defer, analagous to
884 +ignore_unknown and +include_unknown. These options should be used with
885 care, probably only in non-critical host lists such as whitelists.
887 8. There's a new option called queue_only_load_latch, which defaults true.
888 If set false when queue_only_load is greater than zero, Exim re-evaluates
889 the load for each incoming message in an SMTP session. Otherwise, once one
890 message is queued, the remainder are also.
892 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
893 cases when an SMTP session ends without sending QUIT. However, when Exim
894 itself is is bad trouble, such as being unable to write to its log files,
895 this ACL is not run, because it might try to do things (such as write to
896 log files) that make the situation even worse.
898 Like the QUIT ACL, this new ACL is provided to make it possible to gather
899 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
900 modifier is forbidden in this ACL.
902 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
903 to a string that indicates the reason for the termination of the SMTP
904 connection. The possible values are:
906 acl-drop Another ACL issued a "drop" command
907 bad-commands Too many unknown or non-mail commands
908 command-timeout Timeout while reading SMTP commands
909 connection-lost The SMTP connection has been lost
910 data-timeout Timeout while reading message data
911 local-scan-error The local_scan() function crashed
912 local-scan-timeout The local_scan() function timed out
913 signal-exit SIGTERM or SIGINT
914 synchronization-error SMTP synchronization error
915 tls-failed TLS failed to start
917 In most cases when an SMTP connection is closed without having received
918 QUIT, Exim sends an SMTP response message before actually closing the
919 connection. With the exception of acl-drop, the default message can be
920 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
921 "drop" verb in another ACL, it is the message from the other ACL that is
924 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
925 servers with individual queries. This is done by starting the query with
926 "servers=x:y:z;", where each item in the list may take one of two forms:
928 (1) If it is just a host name, the appropriate global option (mysql_servers
929 or pgsql_servers) is searched for a host of the same name, and the
930 remaining parameters (database, user, password) are taken from there.
932 (2) If it contains any slashes, it is taken as a complete parameter set.
934 The list of servers is used in exactly the same was as the global list.
935 Once a connection to a server has happened and a query has been
936 successfully executed, processing of the lookup ceases.
938 This feature is intended for use in master/slave situations where updates
939 are occurring, and one wants to update a master rather than a slave. If the
940 masters are in the list for reading, you might have:
942 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
944 In an updating lookup, you could then write
946 ${lookup mysql{servers=master; UPDATE ...}
948 If, on the other hand, the master is not to be used for reading lookups:
950 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
952 you can still update the master by
954 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
956 11. The message_body_newlines option (default FALSE, for backwards
957 compatibility) can be used to control whether newlines are present in
958 $message_body and $message_body_end. If it is FALSE, they are replaced by
965 1. There is a new log selector called smtp_no_mail, which is not included in
966 the default setting. When it is set, a line is written to the main log
967 whenever an accepted SMTP connection terminates without having issued a
970 2. When an item in a dnslists list is followed by = and & and a list of IP
971 addresses, the behaviour was not clear when the lookup returned more than
972 one IP address. This has been solved by the addition of == and =& for "all"
973 rather than the default "any" matching.
975 3. Up till now, the only control over which cipher suites GnuTLS uses has been
976 for the cipher algorithms. New options have been added to allow some of the
977 other parameters to be varied.
979 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
980 set, Exim compiles a runtime option called disable_fsync.
982 5. There is a new variable called $smtp_count_at_connection_start.
984 6. There's a new control called no_pipelining.
986 7. There are two new variables called $sending_ip_address and $sending_port.
987 These are set whenever an SMTP connection to another host has been set up.
989 8. The expansion of the helo_data option in the smtp transport now happens
990 after the connection to the server has been made.
992 9. There is a new expansion operator ${rfc2047d: that decodes strings that
993 are encoded as per RFC 2047.
995 10. There is a new log selector called "pid", which causes the current process
996 id to be added to every log line, in square brackets, immediately after the
999 11. Exim has been modified so that it flushes SMTP output before implementing
1000 a delay in an ACL. It also flushes the output before performing a callout,
1001 as this can take a substantial time. These behaviours can be disabled by
1002 obeying control = no_delay_flush or control = no_callout_flush,
1003 respectively, at some earlier stage of the connection.
1005 12. There are two new expansion conditions that iterate over a list. They are
1006 called forany and forall.
1008 13. There's a new global option called dsn_from that can be used to vary the
1009 contents of From: lines in bounces and other automatically generated
1010 messages ("delivery status notifications" - hence the name of the option).
1012 14. The smtp transport has a new option called hosts_avoid_pipelining.
1014 15. By default, exigrep does case-insensitive matches. There is now a -I option
1015 that makes it case-sensitive.
1017 16. A number of new features ("addresses", "map", "filter", and "reduce") have
1018 been added to string expansions to make it easier to process lists of
1019 items, typically addresses.
1021 17. There's a new ACL modifier called "continue". It does nothing of itself,
1022 and processing of the ACL always continues with the next condition or
1023 modifier. It is provided so that the side effects of expanding its argument
1026 18. It is now possible to use newline and other control characters (those with
1027 values less than 32, plus DEL) as separators in lists.
1029 19. The exigrep utility now has a -v option, which inverts the matching
1032 20. The host_find_failed option in the manualroute router can now be set to
1039 No new features were added to 4.66.
1045 No new features were added to 4.65.
1051 1. ACL variables can now be given arbitrary names, as long as they start with
1052 "acl_c" or "acl_m" (for connection variables and message variables), are at
1053 least six characters long, with the sixth character being either a digit or
1056 2. There is a new ACL modifier called log_reject_target. It makes it possible
1057 to specify which logs are used for messages about ACL rejections.
1059 3. There is a new authenticator called "dovecot". This is an interface to the
1060 authentication facility of the Dovecot POP/IMAP server, which can support a
1061 number of authentication methods.
1063 4. The variable $message_headers_raw provides a concatenation of all the
1064 messages's headers without any decoding. This is in contrast to
1065 $message_headers, which does RFC2047 decoding on the header contents.
1067 5. In a DNS black list, if two domain names, comma-separated, are given, the
1068 second is used first to do an initial check, making use of any IP value
1069 restrictions that are set. If there is a match, the first domain is used,
1070 without any IP value restrictions, to get the TXT record.
1072 6. All authenticators now have a server_condition option.
1074 7. There is a new command-line option called -Mset. It is useful only in
1075 conjunction with -be (that is, when testing string expansions). It must be
1076 followed by a message id; Exim loads the given message from its spool
1077 before doing the expansions.
1079 8. Another similar new command-line option is called -bem. It operates like
1080 -be except that it must be followed by the name of a file that contains a
1083 9. When an address is delayed because of a 4xx response to a RCPT command, it
1084 is now the combination of sender and recipient that is delayed in
1085 subsequent queue runs until its retry time is reached.
1087 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1088 shift, have been added to the eval: and eval10: expansion items.
1090 11. The variables $interface_address and $interface_port have been renamed
1091 as $received_ip_address and $received_port, to make it clear that they
1092 relate to message reception rather than delivery. (The old names remain
1093 available for compatibility.)
1095 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1096 to vary the message that is sent when an SMTP command is accepted.
1102 1. There is a new Boolean option called filter_prepend_home for the redirect
1105 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1106 start of receiving a non-SMTP message, before any of the message has been
1109 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1110 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1111 start of the message for an SMTP error code.
1113 4. There is a new parameter for LDAP lookups called "referrals", which takes
1114 one of the settings "follow" (the default) or "nofollow".
1116 5. Version 20070721.2 of exipick now included, offering these new options:
1118 After all other sorting options have bee processed, reverse order
1119 before displaying messages (-R is synonym).
1121 Randomize order of matching messages before displaying.
1123 Instead of displaying the matching messages, display the sum
1125 --sort <variable>[,<variable>...]
1126 Before displaying matching messages, sort the messages according to
1127 each messages value for each variable.
1129 Negate the value for every test (returns inverse output from the
1130 same criteria without --not).
1136 1. The ${readsocket expansion item now supports Internet domain sockets as well
1137 as Unix domain sockets. If the first argument begins "inet:", it must be of
1138 the form "inet:host:port". The port is mandatory; it may be a number or the
1139 name of a TCP port in /etc/services. The host may be a name, or it may be an
1140 IP address. An ip address may optionally be enclosed in square brackets.
1141 This is best for IPv6 addresses. For example:
1143 ${readsocket{inet:[::1]:1234}{<request data>}...
1145 Only a single host name may be given, but if looking it up yield more than
1146 one IP address, they are each tried in turn until a connection is made. Once
1147 a connection has been made, the behaviour is as for ${readsocket with a Unix
1150 2. If a redirect router sets up file or pipe deliveries for more than one
1151 incoming address, and the relevant transport has batch_max set greater than
1152 one, a batch delivery now occurs.
1154 3. The appendfile transport has a new option called maildirfolder_create_regex.
1155 Its value is a regular expression. For a maildir delivery, this is matched
1156 against the maildir directory; if it matches, Exim ensures that a
1157 maildirfolder file is created alongside the new, cur, and tmp directories.
1163 The documentation is up-to-date for the 4.61 release. Major new features since
1164 the 4.60 release are:
1166 . An option called disable_ipv6, to disable the use of IPv6 completely.
1168 . An increase in the number of ACL variables to 20 of each type.
1170 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1171 $2, $3, (though those are still set) because the numeric variables get used
1172 for other things in complicated expansions.
1174 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1176 . It is possible to use setclassresources() on some BSD OS to control the
1177 resources used in pipe deliveries.
1179 . A new ACL modifier called add_header, which can be used with any verb.
1181 . More errors are detectable in retry rules.
1183 There are a number of other additions too.
1189 The documentation is up-to-date for the 4.60 release. Major new features since
1190 the 4.50 release are:
1192 . Support for SQLite.
1194 . Support for IGNOREQUOTA in LMTP.
1196 . Extensions to the "submission mode" features.
1198 . Support for Client SMTP Authorization (CSA).
1200 . Support for ratelimiting hosts and users.
1202 . New expansion items to help with the BATV "prvs" scheme.
1204 . A "match_ip" condition, that matches an IP address against a list.
1206 There are many more minor changes.
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