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).
18 3. Feature macros for the compiled-in set of malware scanner interfaces.
20 4. SPF support is promoted from Experimental to mainline status. The template
21 src/EDITME makefile does not enable its inclusion.
23 5. Logging control for DKIM verification. The existing DKIM log line is
24 controlled by a "dkim_verbose" selector which is _not_ enabled by default.
25 A new tag "DKIM=<domain>" is added to <= lines by default, controlled by
26 a "dkim" log_selector.
28 6. Receive duration on <= lines, under a new log_selector "receive_time".
30 7. Options "ipv4_only" and "ipv4_prefer" on the dnslookup router and on
31 routing rules in the manualroute router.
33 8. Expansion item ${sha3:<string>} / ${sha3_<N>:<string>} now also supported
34 under OpenSSL version 1.1.1 or later.
36 9. DKIM operations can now use the Ed25519 algorithm in addition to RSA, under
37 GnuTLS 3.6.0 or later.
43 1. PKG_CONFIG_PATH can now be set in Local/Makefile;
44 wildcards will be expanded, values are collapsed.
46 2. The ${readsocket } expansion now takes an option to not shutdown the
47 connection after sending the query string. The default remains to do so.
49 3. An smtp transport option "hosts_noproxy_tls" to control whether multiple
50 deliveries on a single TCP connection can maintain a TLS connection
51 open. By default disabled for all hosts, doing so saves the cost of
52 making new TLS sessions, at the cost of having to proxy the data via
53 another process. Logging is also affected.
55 4. A malware connection type for the FPSCAND protocol.
57 5. An option for recipient verify callouts to hold the connection open for
58 further recipients and for delivery.
60 6. The reproducible build $SOURCE_DATE_EPOCH environment variable is now
63 7. Optionally, an alternate format for spool data-files which matches the
64 wire format - meaning more efficient reception and transmission (at the
65 cost of difficulty with standard Unix tools). Only used for messages
66 received using the ESMTP CHUNKING option, and when a new main-section
67 option "spool_wireformat" (false by default) is set.
69 8. New main configuration option "commandline_checks_require_admin" to
70 restrict who can use various introspection options.
72 9. New option modifier "no_check" for quota and quota_filecount
75 10. Variable $smtp_command_history returning a comma-sep list of recent
78 11. Millisecond timetamps in logs, on log_selector "millisec". Also affects
79 log elements QT, DT and D, and timstamps in debug output.
81 12. TCP Fast Open logging. As a server, logs when the SMTP banner was sent
82 while still in SYN_RECV state; as a client logs when the connection
83 is opened with a TFO cookie.
85 13. DKIM support for multiple signing, by domain and/or key-selector.
86 DKIM support for multiple hashes, and for alternate-identity tags.
87 Builtin macro with default list of signed headers.
88 Better syntax for specifying oversigning.
89 The DKIM ACL can override verification status, and status is visible in
92 14. Exipick understands -C|--config for an alternative Exim
95 15. TCP Fast Open used, with data-on-SYN, for client SMTP via SOCKS5 proxy,
96 for ${readsocket } expansions, and for ClamAV.
98 16. The "-be" expansion test mode now supports macros. Macros are expanded
99 in test lines, and new macros can be defined.
101 17. Support for server-side dual-certificate-stacks (eg. RSA + ECDSA).
107 1. Allow relative config file names for ".include"
109 2. A main-section config option "debug_store" to control the checks on
110 variable locations during store-reset. Normally false but can be enabled
111 when a memory corrution issue is suspected on a production system.
117 1. The new perl_taintmode option allows to run the embedded perl
118 interpreter in taint mode.
120 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
122 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
125 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
126 N can be 224, 256 (default), 384, 512.
127 With GnuTLS 3.5.0 or later, only.
129 5. Facility for named queues: A command-line argument can specify
130 the queue name for a queue operation, and an ACL modifier can set
131 the queue to be used for a message. A $queue_name variable gives
134 6. New expansion operators base32/base32d.
136 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
137 performance increase and network load decrease. Main config option
138 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
141 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
143 9. Expansion operator escape8bit, like escape but not touching newline etc..
145 10. Feature macros, generated from compile options. All start with "_HAVE_"
146 and go on with some roughly recognisable name. Driver macros, for
147 router, transport and authentication drivers; names starting with "_DRIVER_".
148 Option macros, for each configuration-file option; all start with "_OPT_".
149 Use the "-bP macros" command-line option to see what is present.
151 11. Integer values for options can take a "G" multiplier.
153 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
154 returns from the target back to the initiator, rather than spooling the
157 13. New built-in constants available for tls_dhparam and default changed.
159 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
160 out copies of the message spool files for use by 3rd-party scanners.
162 15. A new option on the smtp transport, hosts_try_fastopen. If the system
163 supports it (on Linux it must be enabled in the kernel by the sysadmin)
164 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
165 but it permits a peer that also supports the facility to send its SMTP
166 banner immediately after the SYN,ACK segment rather then waiting for
167 another ACK - so saving up to one roundtrip time. Because it requires
168 previous communication with the peer (we save a cookie from it) this
169 will only become active on frequently-contacted destinations.
171 16. A new syslog_pid option to suppress PID duplication in syslog lines.
177 1. The ACL conditions regex and mime_regex now capture substrings
178 into numeric variables $regex1 to 9, like the "match" expansion condition.
180 2. New $callout_address variable records the address used for a spam=,
181 malware= or verify= callout.
183 3. Transports now take a "max_parallel" option, to limit concurrency.
185 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
186 The latter expands to a 8-element colon-sep set of hex digits including
187 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
188 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
189 The former operator strips leading zeroes and collapses the longest
190 set of 0-groups to a double-colon.
192 5. New "-bP config" support, to dump the effective configuration.
194 6. New $dkim_key_length variable.
196 7. New base64d and base64 expansion items (the existing str2b64 being a
197 synonym of the latter). Add support in base64 for certificates.
199 8. New main configuration option "bounce_return_linesize_limit" to
200 avoid oversize bodies in bounces. The default value matches RFC
203 9. New $initial_cwd expansion variable.
209 1. Support for using the system standard CA bundle.
211 2. New expansion items $config_file, $config_dir, containing the file
212 and directory name of the main configuration file. Also $exim_version.
214 3. New "malware=" support for Avast.
216 4. New "spam=" variant option for Rspamd.
218 5. Assorted options on malware= and spam= scanners.
220 6. A command-line option to write a comment into the logfile.
222 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
223 be configured to make connections via socks5 proxies.
225 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
226 the transmission of UTF-8 envelope addresses.
228 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
229 used encoding of Maildir folder names.
231 10. A logging option for slow DNS lookups.
233 11. New ${env {<variable>}} expansion.
235 12. A non-SMTP authenticator using information from TLS client certificates.
237 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
238 Patch originally by Wolfgang Breyha.
240 14. Main option "dns_trust_aa" for trusting your local nameserver at the
241 same level as DNSSEC.
247 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
248 DANE SMTP draft to assess a secure chain of trust of the certificate
249 used to establish the TLS connection based on a TLSA record in the
250 domain of the sender.
252 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
253 and several new events have been created. The reason is because it has
254 been expanded beyond just firing events during the transport phase. Any
255 existing TPDA transport options will have to be rewritten to use a new
256 $event_name expansion variable in a condition. Refer to the
257 experimental-spec.txt for details and examples.
259 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
260 server certs used for TLS match the result of the MX lookup. It does
261 not use the same mechanism as DANE.
271 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
272 configured to expect an initial header from a proxy that will make the
273 actual external source IP:host be used in exim instead of the IP of the
274 proxy that is connecting to it.
276 2. New verify option header_names_ascii, which will check to make sure
277 there are no non-ASCII characters in header names. Exim itself handles
278 those non-ASCII characters, but downstream apps may not, so Exim can
279 detect and reject if those characters are present.
281 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
282 codepoints with valid ones.
284 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
285 command line and matching a regex against the return data for trigger
286 and a second regex to extract malware_name. The mail spoolfile name can
287 be included in the command line.
289 5. The smtp transport now supports options "tls_verify_hosts" and
290 "tls_try_verify_hosts". If either is set the certificate verification
291 is split from the encryption operation. The default remains that a failed
292 verification cancels the encryption.
294 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
295 lookup can now set a list of servers to use that is different from the
298 7. New command-line option -C for exiqgrep to specify alternate exim.conf
299 file when searching the queue.
301 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
303 9. Support for DNSSEC on outbound connections.
305 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
306 "certextract" to extract fields from them. Hash operators md5 and sha1
307 work over them for generating fingerprints, and a new sha256 operator
310 11. PRDR is now supported dy default.
312 12. OCSP stapling is now supported by default.
314 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
315 Delivery Status Notification messages in MIME format, and negotiate
316 DSN features per RFC 3461.
322 1. New command-line option -bI:sieve will list all supported sieve extensions
323 of this Exim build on standard output, one per line.
324 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
325 query this to establish the correct list to include in the protocol's
326 SIEVE capability line.
328 2. If the -n option is combined with the -bP option, then the name of an
329 emitted option is not output, only the value (if visible to you).
330 For instance, "exim -n -bP pid_file_path" should just emit a pathname
331 followed by a newline, and no other text.
333 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
334 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
335 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
336 acceptable for security. (Option accepted but ignored if using OpenSSL).
337 Defaults to 1024, the old value. May be lowered only to 512, or raised as
338 far as you like. Raising this may hinder TLS interoperability with other
339 sites and is not currently recommended. Lowering this will permit you to
340 establish a TLS session which is not as secure as you might like.
342 Unless you really know what you are doing, leave it alone.
344 4. If not built with DISABLE_DNSSEC, Exim now has the main option
345 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
346 to send the DO flag to your recursive resolver. If you have a recursive
347 resolver, which can set the Authenticated Data (AD) flag in results, Exim
348 can now detect this. Exim does not perform validation itself, instead
349 relying upon a trusted path to the resolver.
351 Current status: work-in-progress; $sender_host_dnssec variable added.
353 5. DSCP support for outbound connections: on a transport using the smtp driver,
354 set "dscp = ef", for instance, to cause the connections to have the relevant
355 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
357 Similarly for inbound connections, there is a new control modifier, dscp,
358 so "warn control = dscp/ef" in the connect ACL, or after authentication.
360 Supported values depend upon system libraries. "exim -bI:dscp" to list the
361 ones Exim knows of. You can also set a raw number 0..0x3F.
363 6. The -G command-line flag is no longer ignored; it is now equivalent to an
364 ACL setting "control = suppress_local_fixups". The -L command-line flag
365 is now accepted and forces use of syslog, with the provided tag as the
366 process name. A few other flags used by Sendmail are now accepted and
369 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
370 ACL modifier; works for single-recipient mails which are received on and
371 deliverable via SMTP. Using the connection made for a recipient verify,
372 if requested before the verify, or a new one made for the purpose while
373 the inbound connection is still active. The bulk of the mail item is copied
374 direct from the inbound socket to the outbound (as well as the spool file).
375 When the source notifies the end of data, the data acceptance by the destination
376 is negotiated before the acceptance is sent to the source. If the destination
377 does not accept the mail item, for example due to content-scanning, the item
378 is not accepted from the source and therefore there is no need to generate
379 a bounce mail. This is of benefit when providing a secondary-MX service.
380 The downside is that delays are under the control of the ultimate destination
383 The Received-by: header on items delivered by cutthrough is generated
384 early in reception rather than at the end; this will affect any timestamp
385 included. The log line showing delivery is recorded before that showing
386 reception; it uses a new ">>" tag instead of "=>".
388 To support the feature, verify-callout connections can now use ESMTP and TLS.
389 The usual smtp transport options are honoured, plus a (new, default everything)
390 hosts_verify_avoid_tls.
392 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
393 for specific access to the information for each connection. The old names
394 are present for now but deprecated.
396 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
398 8. New expansion operators ${listnamed:name} to get the content of a named list
399 and ${listcount:string} to count the items in a list.
401 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
402 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
403 modules. For some situations this is desirable, but we expect admin in
404 those situations to know they want the feature. More commonly, it means
405 that GUI user modules get loaded and are broken by the setuid Exim being
406 unable to access files specified in environment variables and passed
407 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
408 unless this new option is set.
410 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
411 so have also added a build option which can be used to build Exim with GnuTLS
412 but without trying to use any kind of PKCS11 support. Uncomment this in the
415 AVOID_GNUTLS_PKCS11=yes
417 10. The "acl = name" condition on an ACL now supports optional arguments.
418 New expansion item "${acl {name}{arg}...}" and expansion condition
419 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
420 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
421 Variable $acl_narg contains the number of arguments. If the ACL sets
422 a "message =" value this becomes the result of the expansion item,
423 or the value of $value for the expansion condition. If the ACL returns
424 accept the expansion condition is true; if reject, false. A defer
425 return results in a forced fail.
427 11. Routers and transports can now have multiple headers_add and headers_remove
428 option lines. The concatenated list is used.
430 12. New ACL modifier "remove_header" can remove headers before message gets
431 handled by routers/transports.
433 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
434 "aaaa" and "a" lookups is done and the full set of results returned.
436 14. New expansion variable $headers_added with content from ACL add_header
437 modifier (but not yet added to message).
439 15. New 8bitmime status logging option for received messages. Log field "M8S".
441 16. New authenticated_sender logging option, adding to log field "A".
443 17. New expansion variables $router_name and $transport_name. Useful
444 particularly for debug_print as -bt command-line option does not
445 require privilege whereas -d does.
447 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
448 proposed extension to SMTP from Eric Hall.
450 19. The pipe transport has gained the force_command option, to allow
451 decorating commands from user .forward pipe aliases with prefix
452 wrappers, for instance.
454 20. Callout connections can now AUTH; the same controls as normal delivery
457 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
458 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
459 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
460 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
461 dmarc_status. It adds new control flags dmarc_disable_verify and
462 dmarc_enable_forensic. The default for the dmarc_tld_file option is
463 "/etc/exim/opendmarc.tlds" and can be changed via EDITME.
465 22. Add expansion variable $authenticated_fail_id, which is the username
466 provided to the authentication method which failed. It is available
467 for use in subsequent ACL processing (typically quit or notquit ACLs).
469 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
472 24. New ${hexquote:..string..} expansion operator converts non-printable
473 characters in the string to \xNN form.
475 25. Experimental TPDA (Transport Post Delivery Action) function added.
476 Patch provided by Axel Rau.
478 26. Experimental Redis lookup added. Patch provided by Warren Baker.
484 1. New authenticator driver, "gsasl". Server-only (at present).
485 This is a SASL interface, licensed under GPL, which can be found at
486 http://www.gnu.org/software/gsasl/.
487 This system does not provide sources of data for authentication, so
488 careful use needs to be made of the conditions in Exim.
490 2. New authenticator driver, "heimdal_gssapi". Server-only.
491 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
492 is no longer honoured for setuid programs by Heimdal. Use the
493 "server_keytab" option to point to the keytab.
495 3. The "pkg-config" system can now be used when building Exim to reference
496 cflags and library information for lookups and authenticators, rather
497 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
498 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
499 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
501 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
502 find the headers and libraries for PCRE.
504 4. New expansion variable $tls_bits.
506 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
507 be joined together with ASCII NUL characters to construct the key to pass
508 into the DBM library. Can be used with gsasl to access sasldb2 files as
511 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
513 Avoid release 1.0.1a if you can. Note that the default value of
514 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
515 increased susceptibility to attack. This may still have interoperability
516 implications for very old clients (see version 4.31 change 37) but
517 administrators can choose to make the trade-off themselves and restore
518 compatibility at the cost of session security.
520 7. Use of the new expansion variable $tls_sni in the main configuration option
521 tls_certificate will cause Exim to re-expand the option, if the client
522 sends the TLS Server Name Indication extension, to permit choosing a
523 different certificate; tls_privatekey will also be re-expanded. You must
524 still set these options to expand to valid files when $tls_sni is not set.
526 The SMTP Transport has gained the option tls_sni, which will set a hostname
527 for outbound TLS sessions, and set $tls_sni too.
529 A new log_selector, +tls_sni, has been added, to log received SNI values
530 for Exim as a server.
532 8. The existing "accept_8bitmime" option now defaults to true. This means
533 that Exim is deliberately not strictly RFC compliant. We're following
534 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
535 Those who disagree, or know that they are talking to mail servers that,
536 even today, are not 8-bit clean, need to turn off this option.
538 9. Exim can now be started with -bw (with an optional timeout, given as
539 -bw<timespec>). With this, stdin at startup is a socket that is
540 already listening for connections. This has a more modern name of
541 "socket activation", but forcing the activated socket to fd 0. We're
542 interested in adding more support for modern variants.
544 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
545 for numbers indicates multiplication by 1024^3.
547 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
548 gnutls_require_mac & gnutls_require_protocols are no longer supported.
549 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
550 string, documentation for which is at:
551 http://www.gnutls.org/manual/html_node/Priority-Strings.html
553 SNI support has been added to Exim's GnuTLS integration too.
555 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
556 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
558 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
559 is now available. If the contents of the file are valid, then Exim will
560 send that back in response to a TLS status request; this is OCSP Stapling.
561 Exim will not maintain the contents of the file in any way: administrators
562 are responsible for ensuring that it is up-to-date.
564 See "experimental-spec.txt" for more details.
566 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
567 identically to TXT record lookups.
569 14. New expansion variable $tod_epoch_l for higher-precision time.
571 15. New global option tls_dh_max_bits, defaulting to current value of NSS
572 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
573 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
575 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
576 Option can now be a path or an identifier for a standard prime.
577 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
578 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
581 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
582 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
583 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
589 1. New options for the ratelimit ACL condition: /count= and /unique=.
590 The /noupdate option has been replaced by a /readonly option.
592 2. The SMTP transport's protocol option may now be set to "smtps", to
593 use SSL-on-connect outbound.
595 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
596 there is a problem talking to the AV scanner, or the AV scanner running.
598 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
599 and check if the search item is a member of the list. This does not
600 support named lists, but does subject the list part to string expansion.
602 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
603 built, Exim no longer performs string expansion on the second string of
604 the match_* expansion conditions: "match_address", "match_domain",
605 "match_ip" & "match_local_part". Named lists can still be used.
611 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
612 or off in the resolver library.
618 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
619 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
620 libraries. The following global options have been added in support of
621 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
622 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
624 2. The pipe transport now takes a boolean option, "freeze_signal", default
625 false. When true, if the external delivery command exits on a signal then
626 Exim will freeze the message in the queue, instead of generating a bounce.
628 3. Log filenames may now use %M as an escape, instead of %D (still available).
629 The %M pattern expands to yyyymm, providing month-level resolution.
631 4. The $message_linecount variable is now updated for the maildir_tag option,
632 in the same way as $message_size, to reflect the real number of lines,
633 including any header additions or removals from transport.
635 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
636 Exim now selects entries randomly, to better scale in a cluster setup.
642 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
643 the flaw permitted the Exim run-time user to cause root to append to
644 arbitrary files of the attacker's choosing, with the content based
645 on content supplied by the attacker.
647 2. Exim now supports loading some lookup types at run-time, using your
648 platform's dlopen() functionality. This has limited platform support
649 and the intention is not to support every variant, it's limited to
650 dlopen(). This permits the main Exim binary to not be linked against
651 all the libraries needed for all the lookup types.
657 NOTE: this version is not guaranteed backwards-compatible, please read the
658 items below carefully
660 1. A new main configuration option, "openssl_options", is available if Exim
661 is built with SSL support provided by OpenSSL. The option allows
662 administrators to specify OpenSSL options to be used on connections;
663 typically this is to set bug compatibility features which the OpenSSL
664 developers have not enabled by default. There may be security
665 consequences for certain options, so these should not be changed
668 2. A new pipe transport option, "permit_coredumps", may help with problem
669 diagnosis in some scenarios. Note that Exim is typically installed as
670 a setuid binary, which on most OSes will inhibit coredumps by default,
671 so that safety mechanism would have to be overridden for this option to
672 be able to take effect.
674 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
675 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
676 Note that this switches Exim to use a new API ("INSTREAM") and a future
677 release of ClamAV will remove support for the old API ("STREAM").
679 The av_scanner option, when set to "clamd", now takes an optional third
680 part, "local", which causes Exim to pass a filename to ClamAV instead of
681 the file content. This is the same behaviour as when clamd is pointed at
682 a Unix-domain socket. For example:
684 av_scanner = clamd:192.0.2.3 1234:local
686 ClamAV's ExtendedDetectionInfo response format is now handled.
688 4. There is now a -bmalware option, restricted to admin users. This option
689 takes one parameter, a filename, and scans that file with Exim's
690 malware-scanning framework. This is intended purely as a debugging aid
691 to ensure that Exim's scanning is working, not to replace other tools.
692 Note that the ACL framework is not invoked, so if av_scanner references
693 ACL variables without a fallback then this will fail.
695 5. There is a new expansion operator, "reverse_ip", which will reverse IP
696 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
698 ${reverse_ip:192.0.2.4}
700 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
701 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
703 6. There is a new ACL control called "debug", to enable debug logging.
704 This allows selective logging of certain incoming transactions within
705 production environments, with some care. It takes two options, "tag"
706 and "opts"; "tag" is included in the filename of the log and "opts"
707 is used as per the -d<options> command-line option. Examples, which
708 don't all make sense in all contexts:
711 control = debug/tag=.$sender_host_address
712 control = debug/opts=+expand+acl
713 control = debug/tag=.$message_exim_id/opts=+expand
715 7. It has always been implicit in the design and the documentation that
716 "the Exim user" is not root. src/EDITME said that using root was
717 "very strongly discouraged". This is not enough to keep people from
718 shooting themselves in the foot in days when many don't configure Exim
719 themselves but via package build managers. The security consequences of
720 running various bits of network code are severe if there should be bugs in
721 them. As such, the Exim user may no longer be root. If configured
722 statically, Exim will refuse to build. If configured as ref:user then Exim
723 will exit shortly after start-up. If you must shoot yourself in the foot,
724 then henceforth you will have to maintain your own local patches to strip
727 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
728 condition logic to determine truth/failure and will fail to expand many
729 strings, bool_lax{} uses the router condition logic, where most strings
731 Note: bool{00} is false, bool_lax{00} is true.
733 9. Routers now support multiple "condition" tests.
735 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
736 Setting this allows an admin to define which entry in the tcpwrappers
737 config file will be used to control access to the daemon. This option
738 is only available when Exim is built with USE_TCP_WRAPPERS. The
739 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
742 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
743 the Exim run-time user, instead of root.
745 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
746 is forced on. This is mitigated by the new build option
747 TRUSTED_CONFIG_LIST which defines a list of configuration files which
748 are trusted; one per line. If a config file is owned by root and matches
749 a pathname in the list, then it may be invoked by the Exim build-time
750 user without Exim relinquishing root privileges.
752 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
753 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
754 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
755 include the main config. As a transition mechanism, we are temporarily
756 providing a work-around: the new build option WHITELIST_D_MACROS provides
757 a colon-separated list of macro names which may be overridden by the Exim
758 run-time user. The values of these macros are constrained to the regex
759 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
765 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
766 writable, the other to locking of MBX folders (not mbox).
768 2. MySQL stored procedures are now supported.
770 3. The dkim_domain transport option is now a list, not a single string, and
771 messages will be signed for each element in the list (discarding
774 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
775 in the presence of multiple character strings within the RR. Prior to 4.70,
776 only the first string would be returned. The dnsdb lookup now, by default,
777 preserves the pre-4.70 semantics, but also now takes an extended output
778 separator specification. The separator can be followed by a semicolon, to
779 concatenate the individual text strings together with no join character,
780 or by a comma and a second separator character, in which case the text
781 strings within a TXT record are joined on that second character.
782 Administrators are reminded that DNS provides no ordering guarantees
783 between multiple records in an RRset. For example:
785 foo.example. IN TXT "a" "b" "c"
786 foo.example. IN TXT "d" "e" "f"
788 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
789 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
790 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
796 1. Native DKIM support without an external library.
797 (Note that if no action to prevent it is taken, a straight upgrade will
798 result in DKIM verification of all signed incoming emails. See spec
799 for details on conditionally disabling)
801 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
803 3. There is now a bool{} expansion condition which maps certain strings to
804 true/false condition values (most likely of use in conjunction with the
805 and{} expansion operator).
807 4. The $spam_score, $spam_bar and $spam_report variables are now available
810 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
811 options, provided that Exim is invoked by an admin_user.
813 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
814 which increases compatibility with older clients at the cost of decreased
815 security. Don't set this unless you need to support such clients.
817 7. There is a new expansion operator, ${randint:...} which will produce a
818 "random" number less than the supplied integer. This randomness is
819 not guaranteed to be cryptographically strong, but depending upon how
820 Exim was built may be better than the most naive schemes.
822 8. Exim now explicitly ensures that SHA256 is available when linked against
825 9. The transport_filter_timeout option now applies to SMTP transports too.
831 1. Preliminary DKIM support in Experimental.
837 1. The body_linecount and body_zerocount C variables are now exported in the
840 2. When a dnslists lookup succeeds, the key that was looked up is now placed
841 in $dnslist_matched. When the key is an IP address, it is not reversed in
842 this variable (though it is, of course, in the actual lookup). In simple
845 deny dnslists = spamhaus.example
847 the key is also available in another variable (in this case,
848 $sender_host_address). In more complicated cases, however, this is not
849 true. For example, using a data lookup might generate a dnslists lookup
852 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
854 If this condition succeeds, the value in $dnslist_matched might be
855 192.168.6.7 (for example).
857 3. Authenticators now have a client_condition option. When Exim is running as
858 a client, it skips an authenticator whose client_condition expansion yields
859 "0", "no", or "false". This can be used, for example, to skip plain text
860 authenticators when the connection is not encrypted by a setting such as:
862 client_condition = ${if !eq{$tls_cipher}{}}
864 Note that the 4.67 documentation states that $tls_cipher contains the
865 cipher used for incoming messages. In fact, during SMTP delivery, it
866 contains the cipher used for the delivery. The same is true for
869 4. There is now a -Mvc <message-id> option, which outputs a copy of the
870 message to the standard output, in RFC 2822 format. The option can be used
871 only by an admin user.
873 5. There is now a /noupdate option for the ratelimit ACL condition. It
874 computes the rate and checks the limit as normal, but it does not update
875 the saved data. This means that, in relevant ACLs, it is possible to lookup
876 the existence of a specified (or auto-generated) ratelimit key without
877 incrementing the ratelimit counter for that key.
879 In order for this to be useful, another ACL entry must set the rate
880 for the same key somewhere (otherwise it will always be zero).
885 # Read the rate; if it doesn't exist or is below the maximum
887 deny ratelimit = 100 / 5m / strict / noupdate
888 log_message = RATE: $sender_rate / $sender_rate_period \
889 (max $sender_rate_limit)
891 [... some other logic and tests...]
893 warn ratelimit = 100 / 5m / strict / per_cmd
894 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
895 (max $sender_rate_limit)
896 condition = ${if le{$sender_rate}{$sender_rate_limit}}
900 6. The variable $max_received_linelength contains the number of bytes in the
901 longest line that was received as part of the message, not counting the
902 line termination character(s).
904 7. Host lists can now include +ignore_defer and +include_defer, analagous to
905 +ignore_unknown and +include_unknown. These options should be used with
906 care, probably only in non-critical host lists such as whitelists.
908 8. There's a new option called queue_only_load_latch, which defaults true.
909 If set false when queue_only_load is greater than zero, Exim re-evaluates
910 the load for each incoming message in an SMTP session. Otherwise, once one
911 message is queued, the remainder are also.
913 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
914 cases when an SMTP session ends without sending QUIT. However, when Exim
915 itself is is bad trouble, such as being unable to write to its log files,
916 this ACL is not run, because it might try to do things (such as write to
917 log files) that make the situation even worse.
919 Like the QUIT ACL, this new ACL is provided to make it possible to gather
920 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
921 modifier is forbidden in this ACL.
923 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
924 to a string that indicates the reason for the termination of the SMTP
925 connection. The possible values are:
927 acl-drop Another ACL issued a "drop" command
928 bad-commands Too many unknown or non-mail commands
929 command-timeout Timeout while reading SMTP commands
930 connection-lost The SMTP connection has been lost
931 data-timeout Timeout while reading message data
932 local-scan-error The local_scan() function crashed
933 local-scan-timeout The local_scan() function timed out
934 signal-exit SIGTERM or SIGINT
935 synchronization-error SMTP synchronization error
936 tls-failed TLS failed to start
938 In most cases when an SMTP connection is closed without having received
939 QUIT, Exim sends an SMTP response message before actually closing the
940 connection. With the exception of acl-drop, the default message can be
941 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
942 "drop" verb in another ACL, it is the message from the other ACL that is
945 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
946 servers with individual queries. This is done by starting the query with
947 "servers=x:y:z;", where each item in the list may take one of two forms:
949 (1) If it is just a host name, the appropriate global option (mysql_servers
950 or pgsql_servers) is searched for a host of the same name, and the
951 remaining parameters (database, user, password) are taken from there.
953 (2) If it contains any slashes, it is taken as a complete parameter set.
955 The list of servers is used in exactly the same was as the global list.
956 Once a connection to a server has happened and a query has been
957 successfully executed, processing of the lookup ceases.
959 This feature is intended for use in master/slave situations where updates
960 are occurring, and one wants to update a master rather than a slave. If the
961 masters are in the list for reading, you might have:
963 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
965 In an updating lookup, you could then write
967 ${lookup mysql{servers=master; UPDATE ...}
969 If, on the other hand, the master is not to be used for reading lookups:
971 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
973 you can still update the master by
975 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
977 11. The message_body_newlines option (default FALSE, for backwards
978 compatibility) can be used to control whether newlines are present in
979 $message_body and $message_body_end. If it is FALSE, they are replaced by
986 1. There is a new log selector called smtp_no_mail, which is not included in
987 the default setting. When it is set, a line is written to the main log
988 whenever an accepted SMTP connection terminates without having issued a
991 2. When an item in a dnslists list is followed by = and & and a list of IP
992 addresses, the behaviour was not clear when the lookup returned more than
993 one IP address. This has been solved by the addition of == and =& for "all"
994 rather than the default "any" matching.
996 3. Up till now, the only control over which cipher suites GnuTLS uses has been
997 for the cipher algorithms. New options have been added to allow some of the
998 other parameters to be varied.
1000 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
1001 set, Exim compiles a runtime option called disable_fsync.
1003 5. There is a new variable called $smtp_count_at_connection_start.
1005 6. There's a new control called no_pipelining.
1007 7. There are two new variables called $sending_ip_address and $sending_port.
1008 These are set whenever an SMTP connection to another host has been set up.
1010 8. The expansion of the helo_data option in the smtp transport now happens
1011 after the connection to the server has been made.
1013 9. There is a new expansion operator ${rfc2047d: that decodes strings that
1014 are encoded as per RFC 2047.
1016 10. There is a new log selector called "pid", which causes the current process
1017 id to be added to every log line, in square brackets, immediately after the
1020 11. Exim has been modified so that it flushes SMTP output before implementing
1021 a delay in an ACL. It also flushes the output before performing a callout,
1022 as this can take a substantial time. These behaviours can be disabled by
1023 obeying control = no_delay_flush or control = no_callout_flush,
1024 respectively, at some earlier stage of the connection.
1026 12. There are two new expansion conditions that iterate over a list. They are
1027 called forany and forall.
1029 13. There's a new global option called dsn_from that can be used to vary the
1030 contents of From: lines in bounces and other automatically generated
1031 messages ("delivery status notifications" - hence the name of the option).
1033 14. The smtp transport has a new option called hosts_avoid_pipelining.
1035 15. By default, exigrep does case-insensitive matches. There is now a -I option
1036 that makes it case-sensitive.
1038 16. A number of new features ("addresses", "map", "filter", and "reduce") have
1039 been added to string expansions to make it easier to process lists of
1040 items, typically addresses.
1042 17. There's a new ACL modifier called "continue". It does nothing of itself,
1043 and processing of the ACL always continues with the next condition or
1044 modifier. It is provided so that the side effects of expanding its argument
1047 18. It is now possible to use newline and other control characters (those with
1048 values less than 32, plus DEL) as separators in lists.
1050 19. The exigrep utility now has a -v option, which inverts the matching
1053 20. The host_find_failed option in the manualroute router can now be set to
1060 No new features were added to 4.66.
1066 No new features were added to 4.65.
1072 1. ACL variables can now be given arbitrary names, as long as they start with
1073 "acl_c" or "acl_m" (for connection variables and message variables), are at
1074 least six characters long, with the sixth character being either a digit or
1077 2. There is a new ACL modifier called log_reject_target. It makes it possible
1078 to specify which logs are used for messages about ACL rejections.
1080 3. There is a new authenticator called "dovecot". This is an interface to the
1081 authentication facility of the Dovecot POP/IMAP server, which can support a
1082 number of authentication methods.
1084 4. The variable $message_headers_raw provides a concatenation of all the
1085 messages's headers without any decoding. This is in contrast to
1086 $message_headers, which does RFC2047 decoding on the header contents.
1088 5. In a DNS black list, if two domain names, comma-separated, are given, the
1089 second is used first to do an initial check, making use of any IP value
1090 restrictions that are set. If there is a match, the first domain is used,
1091 without any IP value restrictions, to get the TXT record.
1093 6. All authenticators now have a server_condition option.
1095 7. There is a new command-line option called -Mset. It is useful only in
1096 conjunction with -be (that is, when testing string expansions). It must be
1097 followed by a message id; Exim loads the given message from its spool
1098 before doing the expansions.
1100 8. Another similar new command-line option is called -bem. It operates like
1101 -be except that it must be followed by the name of a file that contains a
1104 9. When an address is delayed because of a 4xx response to a RCPT command, it
1105 is now the combination of sender and recipient that is delayed in
1106 subsequent queue runs until its retry time is reached.
1108 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1109 shift, have been added to the eval: and eval10: expansion items.
1111 11. The variables $interface_address and $interface_port have been renamed
1112 as $received_ip_address and $received_port, to make it clear that they
1113 relate to message reception rather than delivery. (The old names remain
1114 available for compatibility.)
1116 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1117 to vary the message that is sent when an SMTP command is accepted.
1123 1. There is a new Boolean option called filter_prepend_home for the redirect
1126 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1127 start of receiving a non-SMTP message, before any of the message has been
1130 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1131 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1132 start of the message for an SMTP error code.
1134 4. There is a new parameter for LDAP lookups called "referrals", which takes
1135 one of the settings "follow" (the default) or "nofollow".
1137 5. Version 20070721.2 of exipick now included, offering these new options:
1139 After all other sorting options have bee processed, reverse order
1140 before displaying messages (-R is synonym).
1142 Randomize order of matching messages before displaying.
1144 Instead of displaying the matching messages, display the sum
1146 --sort <variable>[,<variable>...]
1147 Before displaying matching messages, sort the messages according to
1148 each messages value for each variable.
1150 Negate the value for every test (returns inverse output from the
1151 same criteria without --not).
1157 1. The ${readsocket expansion item now supports Internet domain sockets as well
1158 as Unix domain sockets. If the first argument begins "inet:", it must be of
1159 the form "inet:host:port". The port is mandatory; it may be a number or the
1160 name of a TCP port in /etc/services. The host may be a name, or it may be an
1161 IP address. An ip address may optionally be enclosed in square brackets.
1162 This is best for IPv6 addresses. For example:
1164 ${readsocket{inet:[::1]:1234}{<request data>}...
1166 Only a single host name may be given, but if looking it up yield more than
1167 one IP address, they are each tried in turn until a connection is made. Once
1168 a connection has been made, the behaviour is as for ${readsocket with a Unix
1171 2. If a redirect router sets up file or pipe deliveries for more than one
1172 incoming address, and the relevant transport has batch_max set greater than
1173 one, a batch delivery now occurs.
1175 3. The appendfile transport has a new option called maildirfolder_create_regex.
1176 Its value is a regular expression. For a maildir delivery, this is matched
1177 against the maildir directory; if it matches, Exim ensures that a
1178 maildirfolder file is created alongside the new, cur, and tmp directories.
1184 The documentation is up-to-date for the 4.61 release. Major new features since
1185 the 4.60 release are:
1187 . An option called disable_ipv6, to disable the use of IPv6 completely.
1189 . An increase in the number of ACL variables to 20 of each type.
1191 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1192 $2, $3, (though those are still set) because the numeric variables get used
1193 for other things in complicated expansions.
1195 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1197 . It is possible to use setclassresources() on some BSD OS to control the
1198 resources used in pipe deliveries.
1200 . A new ACL modifier called add_header, which can be used with any verb.
1202 . More errors are detectable in retry rules.
1204 There are a number of other additions too.
1210 The documentation is up-to-date for the 4.60 release. Major new features since
1211 the 4.50 release are:
1213 . Support for SQLite.
1215 . Support for IGNOREQUOTA in LMTP.
1217 . Extensions to the "submission mode" features.
1219 . Support for Client SMTP Authorization (CSA).
1221 . Support for ratelimiting hosts and users.
1223 . New expansion items to help with the BATV "prvs" scheme.
1225 . A "match_ip" condition, that matches an IP address against a list.
1227 There are many more minor changes.
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