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.
39 10. Builtin feature-macros _CRYPTO_HASH_SHA3 and _CRYPTO_SIGN_ED25519, library
42 11. "exim -bP macro <name>" returns caller-usable status.
48 1. PKG_CONFIG_PATH can now be set in Local/Makefile;
49 wildcards will be expanded, values are collapsed.
51 2. The ${readsocket } expansion now takes an option to not shutdown the
52 connection after sending the query string. The default remains to do so.
54 3. An smtp transport option "hosts_noproxy_tls" to control whether multiple
55 deliveries on a single TCP connection can maintain a TLS connection
56 open. By default disabled for all hosts, doing so saves the cost of
57 making new TLS sessions, at the cost of having to proxy the data via
58 another process. Logging is also affected.
60 4. A malware connection type for the FPSCAND protocol.
62 5. An option for recipient verify callouts to hold the connection open for
63 further recipients and for delivery.
65 6. The reproducible build $SOURCE_DATE_EPOCH environment variable is now
68 7. Optionally, an alternate format for spool data-files which matches the
69 wire format - meaning more efficient reception and transmission (at the
70 cost of difficulty with standard Unix tools). Only used for messages
71 received using the ESMTP CHUNKING option, and when a new main-section
72 option "spool_wireformat" (false by default) is set.
74 8. New main configuration option "commandline_checks_require_admin" to
75 restrict who can use various introspection options.
77 9. New option modifier "no_check" for quota and quota_filecount
80 10. Variable $smtp_command_history returning a comma-sep list of recent
83 11. Millisecond timetamps in logs, on log_selector "millisec". Also affects
84 log elements QT, DT and D, and timstamps in debug output.
86 12. TCP Fast Open logging. As a server, logs when the SMTP banner was sent
87 while still in SYN_RECV state; as a client logs when the connection
88 is opened with a TFO cookie.
90 13. DKIM support for multiple signing, by domain and/or key-selector.
91 DKIM support for multiple hashes, and for alternate-identity tags.
92 Builtin macro with default list of signed headers.
93 Better syntax for specifying oversigning.
94 The DKIM ACL can override verification status, and status is visible in
97 14. Exipick understands -C|--config for an alternative Exim
100 15. TCP Fast Open used, with data-on-SYN, for client SMTP via SOCKS5 proxy,
101 for ${readsocket } expansions, and for ClamAV.
103 16. The "-be" expansion test mode now supports macros. Macros are expanded
104 in test lines, and new macros can be defined.
106 17. Support for server-side dual-certificate-stacks (eg. RSA + ECDSA).
112 1. Allow relative config file names for ".include"
114 2. A main-section config option "debug_store" to control the checks on
115 variable locations during store-reset. Normally false but can be enabled
116 when a memory corrution issue is suspected on a production system.
122 1. The new perl_taintmode option allows to run the embedded perl
123 interpreter in taint mode.
125 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
127 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
130 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
131 N can be 224, 256 (default), 384, 512.
132 With GnuTLS 3.5.0 or later, only.
134 5. Facility for named queues: A command-line argument can specify
135 the queue name for a queue operation, and an ACL modifier can set
136 the queue to be used for a message. A $queue_name variable gives
139 6. New expansion operators base32/base32d.
141 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
142 performance increase and network load decrease. Main config option
143 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
146 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
148 9. Expansion operator escape8bit, like escape but not touching newline etc..
150 10. Feature macros, generated from compile options. All start with "_HAVE_"
151 and go on with some roughly recognisable name. Driver macros, for
152 router, transport and authentication drivers; names starting with "_DRIVER_".
153 Option macros, for each configuration-file option; all start with "_OPT_".
154 Use the "-bP macros" command-line option to see what is present.
156 11. Integer values for options can take a "G" multiplier.
158 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
159 returns from the target back to the initiator, rather than spooling the
162 13. New built-in constants available for tls_dhparam and default changed.
164 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
165 out copies of the message spool files for use by 3rd-party scanners.
167 15. A new option on the smtp transport, hosts_try_fastopen. If the system
168 supports it (on Linux it must be enabled in the kernel by the sysadmin)
169 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
170 but it permits a peer that also supports the facility to send its SMTP
171 banner immediately after the SYN,ACK segment rather then waiting for
172 another ACK - so saving up to one roundtrip time. Because it requires
173 previous communication with the peer (we save a cookie from it) this
174 will only become active on frequently-contacted destinations.
176 16. A new syslog_pid option to suppress PID duplication in syslog lines.
182 1. The ACL conditions regex and mime_regex now capture substrings
183 into numeric variables $regex1 to 9, like the "match" expansion condition.
185 2. New $callout_address variable records the address used for a spam=,
186 malware= or verify= callout.
188 3. Transports now take a "max_parallel" option, to limit concurrency.
190 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
191 The latter expands to a 8-element colon-sep set of hex digits including
192 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
193 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
194 The former operator strips leading zeroes and collapses the longest
195 set of 0-groups to a double-colon.
197 5. New "-bP config" support, to dump the effective configuration.
199 6. New $dkim_key_length variable.
201 7. New base64d and base64 expansion items (the existing str2b64 being a
202 synonym of the latter). Add support in base64 for certificates.
204 8. New main configuration option "bounce_return_linesize_limit" to
205 avoid oversize bodies in bounces. The default value matches RFC
208 9. New $initial_cwd expansion variable.
214 1. Support for using the system standard CA bundle.
216 2. New expansion items $config_file, $config_dir, containing the file
217 and directory name of the main configuration file. Also $exim_version.
219 3. New "malware=" support for Avast.
221 4. New "spam=" variant option for Rspamd.
223 5. Assorted options on malware= and spam= scanners.
225 6. A command-line option to write a comment into the logfile.
227 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
228 be configured to make connections via socks5 proxies.
230 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
231 the transmission of UTF-8 envelope addresses.
233 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
234 used encoding of Maildir folder names.
236 10. A logging option for slow DNS lookups.
238 11. New ${env {<variable>}} expansion.
240 12. A non-SMTP authenticator using information from TLS client certificates.
242 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
243 Patch originally by Wolfgang Breyha.
245 14. Main option "dns_trust_aa" for trusting your local nameserver at the
246 same level as DNSSEC.
252 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
253 DANE SMTP draft to assess a secure chain of trust of the certificate
254 used to establish the TLS connection based on a TLSA record in the
255 domain of the sender.
257 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
258 and several new events have been created. The reason is because it has
259 been expanded beyond just firing events during the transport phase. Any
260 existing TPDA transport options will have to be rewritten to use a new
261 $event_name expansion variable in a condition. Refer to the
262 experimental-spec.txt for details and examples.
264 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
265 server certs used for TLS match the result of the MX lookup. It does
266 not use the same mechanism as DANE.
276 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
277 configured to expect an initial header from a proxy that will make the
278 actual external source IP:host be used in exim instead of the IP of the
279 proxy that is connecting to it.
281 2. New verify option header_names_ascii, which will check to make sure
282 there are no non-ASCII characters in header names. Exim itself handles
283 those non-ASCII characters, but downstream apps may not, so Exim can
284 detect and reject if those characters are present.
286 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
287 codepoints with valid ones.
289 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
290 command line and matching a regex against the return data for trigger
291 and a second regex to extract malware_name. The mail spoolfile name can
292 be included in the command line.
294 5. The smtp transport now supports options "tls_verify_hosts" and
295 "tls_try_verify_hosts". If either is set the certificate verification
296 is split from the encryption operation. The default remains that a failed
297 verification cancels the encryption.
299 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
300 lookup can now set a list of servers to use that is different from the
303 7. New command-line option -C for exiqgrep to specify alternate exim.conf
304 file when searching the queue.
306 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
308 9. Support for DNSSEC on outbound connections.
310 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
311 "certextract" to extract fields from them. Hash operators md5 and sha1
312 work over them for generating fingerprints, and a new sha256 operator
315 11. PRDR is now supported dy default.
317 12. OCSP stapling is now supported by default.
319 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
320 Delivery Status Notification messages in MIME format, and negotiate
321 DSN features per RFC 3461.
327 1. New command-line option -bI:sieve will list all supported sieve extensions
328 of this Exim build on standard output, one per line.
329 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
330 query this to establish the correct list to include in the protocol's
331 SIEVE capability line.
333 2. If the -n option is combined with the -bP option, then the name of an
334 emitted option is not output, only the value (if visible to you).
335 For instance, "exim -n -bP pid_file_path" should just emit a pathname
336 followed by a newline, and no other text.
338 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
339 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
340 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
341 acceptable for security. (Option accepted but ignored if using OpenSSL).
342 Defaults to 1024, the old value. May be lowered only to 512, or raised as
343 far as you like. Raising this may hinder TLS interoperability with other
344 sites and is not currently recommended. Lowering this will permit you to
345 establish a TLS session which is not as secure as you might like.
347 Unless you really know what you are doing, leave it alone.
349 4. If not built with DISABLE_DNSSEC, Exim now has the main option
350 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
351 to send the DO flag to your recursive resolver. If you have a recursive
352 resolver, which can set the Authenticated Data (AD) flag in results, Exim
353 can now detect this. Exim does not perform validation itself, instead
354 relying upon a trusted path to the resolver.
356 Current status: work-in-progress; $sender_host_dnssec variable added.
358 5. DSCP support for outbound connections: on a transport using the smtp driver,
359 set "dscp = ef", for instance, to cause the connections to have the relevant
360 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
362 Similarly for inbound connections, there is a new control modifier, dscp,
363 so "warn control = dscp/ef" in the connect ACL, or after authentication.
365 Supported values depend upon system libraries. "exim -bI:dscp" to list the
366 ones Exim knows of. You can also set a raw number 0..0x3F.
368 6. The -G command-line flag is no longer ignored; it is now equivalent to an
369 ACL setting "control = suppress_local_fixups". The -L command-line flag
370 is now accepted and forces use of syslog, with the provided tag as the
371 process name. A few other flags used by Sendmail are now accepted and
374 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
375 ACL modifier; works for single-recipient mails which are received on and
376 deliverable via SMTP. Using the connection made for a recipient verify,
377 if requested before the verify, or a new one made for the purpose while
378 the inbound connection is still active. The bulk of the mail item is copied
379 direct from the inbound socket to the outbound (as well as the spool file).
380 When the source notifies the end of data, the data acceptance by the destination
381 is negotiated before the acceptance is sent to the source. If the destination
382 does not accept the mail item, for example due to content-scanning, the item
383 is not accepted from the source and therefore there is no need to generate
384 a bounce mail. This is of benefit when providing a secondary-MX service.
385 The downside is that delays are under the control of the ultimate destination
388 The Received-by: header on items delivered by cutthrough is generated
389 early in reception rather than at the end; this will affect any timestamp
390 included. The log line showing delivery is recorded before that showing
391 reception; it uses a new ">>" tag instead of "=>".
393 To support the feature, verify-callout connections can now use ESMTP and TLS.
394 The usual smtp transport options are honoured, plus a (new, default everything)
395 hosts_verify_avoid_tls.
397 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
398 for specific access to the information for each connection. The old names
399 are present for now but deprecated.
401 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
403 8. New expansion operators ${listnamed:name} to get the content of a named list
404 and ${listcount:string} to count the items in a list.
406 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
407 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
408 modules. For some situations this is desirable, but we expect admin in
409 those situations to know they want the feature. More commonly, it means
410 that GUI user modules get loaded and are broken by the setuid Exim being
411 unable to access files specified in environment variables and passed
412 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
413 unless this new option is set.
415 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
416 so have also added a build option which can be used to build Exim with GnuTLS
417 but without trying to use any kind of PKCS11 support. Uncomment this in the
420 AVOID_GNUTLS_PKCS11=yes
422 10. The "acl = name" condition on an ACL now supports optional arguments.
423 New expansion item "${acl {name}{arg}...}" and expansion condition
424 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
425 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
426 Variable $acl_narg contains the number of arguments. If the ACL sets
427 a "message =" value this becomes the result of the expansion item,
428 or the value of $value for the expansion condition. If the ACL returns
429 accept the expansion condition is true; if reject, false. A defer
430 return results in a forced fail.
432 11. Routers and transports can now have multiple headers_add and headers_remove
433 option lines. The concatenated list is used.
435 12. New ACL modifier "remove_header" can remove headers before message gets
436 handled by routers/transports.
438 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
439 "aaaa" and "a" lookups is done and the full set of results returned.
441 14. New expansion variable $headers_added with content from ACL add_header
442 modifier (but not yet added to message).
444 15. New 8bitmime status logging option for received messages. Log field "M8S".
446 16. New authenticated_sender logging option, adding to log field "A".
448 17. New expansion variables $router_name and $transport_name. Useful
449 particularly for debug_print as -bt command-line option does not
450 require privilege whereas -d does.
452 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
453 proposed extension to SMTP from Eric Hall.
455 19. The pipe transport has gained the force_command option, to allow
456 decorating commands from user .forward pipe aliases with prefix
457 wrappers, for instance.
459 20. Callout connections can now AUTH; the same controls as normal delivery
462 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
463 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
464 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
465 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
466 dmarc_status. It adds new control flags dmarc_disable_verify and
467 dmarc_enable_forensic. The default for the dmarc_tld_file option is
468 "/etc/exim/opendmarc.tlds" and can be changed via EDITME.
470 22. Add expansion variable $authenticated_fail_id, which is the username
471 provided to the authentication method which failed. It is available
472 for use in subsequent ACL processing (typically quit or notquit ACLs).
474 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
477 24. New ${hexquote:..string..} expansion operator converts non-printable
478 characters in the string to \xNN form.
480 25. Experimental TPDA (Transport Post Delivery Action) function added.
481 Patch provided by Axel Rau.
483 26. Experimental Redis lookup added. Patch provided by Warren Baker.
489 1. New authenticator driver, "gsasl". Server-only (at present).
490 This is a SASL interface, licensed under GPL, which can be found at
491 http://www.gnu.org/software/gsasl/.
492 This system does not provide sources of data for authentication, so
493 careful use needs to be made of the conditions in Exim.
495 2. New authenticator driver, "heimdal_gssapi". Server-only.
496 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
497 is no longer honoured for setuid programs by Heimdal. Use the
498 "server_keytab" option to point to the keytab.
500 3. The "pkg-config" system can now be used when building Exim to reference
501 cflags and library information for lookups and authenticators, rather
502 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
503 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
504 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
506 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
507 find the headers and libraries for PCRE.
509 4. New expansion variable $tls_bits.
511 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
512 be joined together with ASCII NUL characters to construct the key to pass
513 into the DBM library. Can be used with gsasl to access sasldb2 files as
516 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
518 Avoid release 1.0.1a if you can. Note that the default value of
519 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
520 increased susceptibility to attack. This may still have interoperability
521 implications for very old clients (see version 4.31 change 37) but
522 administrators can choose to make the trade-off themselves and restore
523 compatibility at the cost of session security.
525 7. Use of the new expansion variable $tls_sni in the main configuration option
526 tls_certificate will cause Exim to re-expand the option, if the client
527 sends the TLS Server Name Indication extension, to permit choosing a
528 different certificate; tls_privatekey will also be re-expanded. You must
529 still set these options to expand to valid files when $tls_sni is not set.
531 The SMTP Transport has gained the option tls_sni, which will set a hostname
532 for outbound TLS sessions, and set $tls_sni too.
534 A new log_selector, +tls_sni, has been added, to log received SNI values
535 for Exim as a server.
537 8. The existing "accept_8bitmime" option now defaults to true. This means
538 that Exim is deliberately not strictly RFC compliant. We're following
539 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
540 Those who disagree, or know that they are talking to mail servers that,
541 even today, are not 8-bit clean, need to turn off this option.
543 9. Exim can now be started with -bw (with an optional timeout, given as
544 -bw<timespec>). With this, stdin at startup is a socket that is
545 already listening for connections. This has a more modern name of
546 "socket activation", but forcing the activated socket to fd 0. We're
547 interested in adding more support for modern variants.
549 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
550 for numbers indicates multiplication by 1024^3.
552 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
553 gnutls_require_mac & gnutls_require_protocols are no longer supported.
554 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
555 string, documentation for which is at:
556 http://www.gnutls.org/manual/html_node/Priority-Strings.html
558 SNI support has been added to Exim's GnuTLS integration too.
560 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
561 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
563 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
564 is now available. If the contents of the file are valid, then Exim will
565 send that back in response to a TLS status request; this is OCSP Stapling.
566 Exim will not maintain the contents of the file in any way: administrators
567 are responsible for ensuring that it is up-to-date.
569 See "experimental-spec.txt" for more details.
571 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
572 identically to TXT record lookups.
574 14. New expansion variable $tod_epoch_l for higher-precision time.
576 15. New global option tls_dh_max_bits, defaulting to current value of NSS
577 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
578 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
580 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
581 Option can now be a path or an identifier for a standard prime.
582 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
583 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
586 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
587 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
588 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
594 1. New options for the ratelimit ACL condition: /count= and /unique=.
595 The /noupdate option has been replaced by a /readonly option.
597 2. The SMTP transport's protocol option may now be set to "smtps", to
598 use SSL-on-connect outbound.
600 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
601 there is a problem talking to the AV scanner, or the AV scanner running.
603 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
604 and check if the search item is a member of the list. This does not
605 support named lists, but does subject the list part to string expansion.
607 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
608 built, Exim no longer performs string expansion on the second string of
609 the match_* expansion conditions: "match_address", "match_domain",
610 "match_ip" & "match_local_part". Named lists can still be used.
616 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
617 or off in the resolver library.
623 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
624 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
625 libraries. The following global options have been added in support of
626 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
627 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
629 2. The pipe transport now takes a boolean option, "freeze_signal", default
630 false. When true, if the external delivery command exits on a signal then
631 Exim will freeze the message in the queue, instead of generating a bounce.
633 3. Log filenames may now use %M as an escape, instead of %D (still available).
634 The %M pattern expands to yyyymm, providing month-level resolution.
636 4. The $message_linecount variable is now updated for the maildir_tag option,
637 in the same way as $message_size, to reflect the real number of lines,
638 including any header additions or removals from transport.
640 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
641 Exim now selects entries randomly, to better scale in a cluster setup.
647 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
648 the flaw permitted the Exim run-time user to cause root to append to
649 arbitrary files of the attacker's choosing, with the content based
650 on content supplied by the attacker.
652 2. Exim now supports loading some lookup types at run-time, using your
653 platform's dlopen() functionality. This has limited platform support
654 and the intention is not to support every variant, it's limited to
655 dlopen(). This permits the main Exim binary to not be linked against
656 all the libraries needed for all the lookup types.
662 NOTE: this version is not guaranteed backwards-compatible, please read the
663 items below carefully
665 1. A new main configuration option, "openssl_options", is available if Exim
666 is built with SSL support provided by OpenSSL. The option allows
667 administrators to specify OpenSSL options to be used on connections;
668 typically this is to set bug compatibility features which the OpenSSL
669 developers have not enabled by default. There may be security
670 consequences for certain options, so these should not be changed
673 2. A new pipe transport option, "permit_coredumps", may help with problem
674 diagnosis in some scenarios. Note that Exim is typically installed as
675 a setuid binary, which on most OSes will inhibit coredumps by default,
676 so that safety mechanism would have to be overridden for this option to
677 be able to take effect.
679 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
680 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
681 Note that this switches Exim to use a new API ("INSTREAM") and a future
682 release of ClamAV will remove support for the old API ("STREAM").
684 The av_scanner option, when set to "clamd", now takes an optional third
685 part, "local", which causes Exim to pass a filename to ClamAV instead of
686 the file content. This is the same behaviour as when clamd is pointed at
687 a Unix-domain socket. For example:
689 av_scanner = clamd:192.0.2.3 1234:local
691 ClamAV's ExtendedDetectionInfo response format is now handled.
693 4. There is now a -bmalware option, restricted to admin users. This option
694 takes one parameter, a filename, and scans that file with Exim's
695 malware-scanning framework. This is intended purely as a debugging aid
696 to ensure that Exim's scanning is working, not to replace other tools.
697 Note that the ACL framework is not invoked, so if av_scanner references
698 ACL variables without a fallback then this will fail.
700 5. There is a new expansion operator, "reverse_ip", which will reverse IP
701 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
703 ${reverse_ip:192.0.2.4}
705 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
706 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
708 6. There is a new ACL control called "debug", to enable debug logging.
709 This allows selective logging of certain incoming transactions within
710 production environments, with some care. It takes two options, "tag"
711 and "opts"; "tag" is included in the filename of the log and "opts"
712 is used as per the -d<options> command-line option. Examples, which
713 don't all make sense in all contexts:
716 control = debug/tag=.$sender_host_address
717 control = debug/opts=+expand+acl
718 control = debug/tag=.$message_exim_id/opts=+expand
720 7. It has always been implicit in the design and the documentation that
721 "the Exim user" is not root. src/EDITME said that using root was
722 "very strongly discouraged". This is not enough to keep people from
723 shooting themselves in the foot in days when many don't configure Exim
724 themselves but via package build managers. The security consequences of
725 running various bits of network code are severe if there should be bugs in
726 them. As such, the Exim user may no longer be root. If configured
727 statically, Exim will refuse to build. If configured as ref:user then Exim
728 will exit shortly after start-up. If you must shoot yourself in the foot,
729 then henceforth you will have to maintain your own local patches to strip
732 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
733 condition logic to determine truth/failure and will fail to expand many
734 strings, bool_lax{} uses the router condition logic, where most strings
736 Note: bool{00} is false, bool_lax{00} is true.
738 9. Routers now support multiple "condition" tests.
740 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
741 Setting this allows an admin to define which entry in the tcpwrappers
742 config file will be used to control access to the daemon. This option
743 is only available when Exim is built with USE_TCP_WRAPPERS. The
744 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
747 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
748 the Exim run-time user, instead of root.
750 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
751 is forced on. This is mitigated by the new build option
752 TRUSTED_CONFIG_LIST which defines a list of configuration files which
753 are trusted; one per line. If a config file is owned by root and matches
754 a pathname in the list, then it may be invoked by the Exim build-time
755 user without Exim relinquishing root privileges.
757 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
758 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
759 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
760 include the main config. As a transition mechanism, we are temporarily
761 providing a work-around: the new build option WHITELIST_D_MACROS provides
762 a colon-separated list of macro names which may be overridden by the Exim
763 run-time user. The values of these macros are constrained to the regex
764 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
770 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
771 writable, the other to locking of MBX folders (not mbox).
773 2. MySQL stored procedures are now supported.
775 3. The dkim_domain transport option is now a list, not a single string, and
776 messages will be signed for each element in the list (discarding
779 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
780 in the presence of multiple character strings within the RR. Prior to 4.70,
781 only the first string would be returned. The dnsdb lookup now, by default,
782 preserves the pre-4.70 semantics, but also now takes an extended output
783 separator specification. The separator can be followed by a semicolon, to
784 concatenate the individual text strings together with no join character,
785 or by a comma and a second separator character, in which case the text
786 strings within a TXT record are joined on that second character.
787 Administrators are reminded that DNS provides no ordering guarantees
788 between multiple records in an RRset. For example:
790 foo.example. IN TXT "a" "b" "c"
791 foo.example. IN TXT "d" "e" "f"
793 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
794 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
795 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
801 1. Native DKIM support without an external library.
802 (Note that if no action to prevent it is taken, a straight upgrade will
803 result in DKIM verification of all signed incoming emails. See spec
804 for details on conditionally disabling)
806 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
808 3. There is now a bool{} expansion condition which maps certain strings to
809 true/false condition values (most likely of use in conjunction with the
810 and{} expansion operator).
812 4. The $spam_score, $spam_bar and $spam_report variables are now available
815 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
816 options, provided that Exim is invoked by an admin_user.
818 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
819 which increases compatibility with older clients at the cost of decreased
820 security. Don't set this unless you need to support such clients.
822 7. There is a new expansion operator, ${randint:...} which will produce a
823 "random" number less than the supplied integer. This randomness is
824 not guaranteed to be cryptographically strong, but depending upon how
825 Exim was built may be better than the most naive schemes.
827 8. Exim now explicitly ensures that SHA256 is available when linked against
830 9. The transport_filter_timeout option now applies to SMTP transports too.
836 1. Preliminary DKIM support in Experimental.
842 1. The body_linecount and body_zerocount C variables are now exported in the
845 2. When a dnslists lookup succeeds, the key that was looked up is now placed
846 in $dnslist_matched. When the key is an IP address, it is not reversed in
847 this variable (though it is, of course, in the actual lookup). In simple
850 deny dnslists = spamhaus.example
852 the key is also available in another variable (in this case,
853 $sender_host_address). In more complicated cases, however, this is not
854 true. For example, using a data lookup might generate a dnslists lookup
857 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
859 If this condition succeeds, the value in $dnslist_matched might be
860 192.168.6.7 (for example).
862 3. Authenticators now have a client_condition option. When Exim is running as
863 a client, it skips an authenticator whose client_condition expansion yields
864 "0", "no", or "false". This can be used, for example, to skip plain text
865 authenticators when the connection is not encrypted by a setting such as:
867 client_condition = ${if !eq{$tls_cipher}{}}
869 Note that the 4.67 documentation states that $tls_cipher contains the
870 cipher used for incoming messages. In fact, during SMTP delivery, it
871 contains the cipher used for the delivery. The same is true for
874 4. There is now a -Mvc <message-id> option, which outputs a copy of the
875 message to the standard output, in RFC 2822 format. The option can be used
876 only by an admin user.
878 5. There is now a /noupdate option for the ratelimit ACL condition. It
879 computes the rate and checks the limit as normal, but it does not update
880 the saved data. This means that, in relevant ACLs, it is possible to lookup
881 the existence of a specified (or auto-generated) ratelimit key without
882 incrementing the ratelimit counter for that key.
884 In order for this to be useful, another ACL entry must set the rate
885 for the same key somewhere (otherwise it will always be zero).
890 # Read the rate; if it doesn't exist or is below the maximum
892 deny ratelimit = 100 / 5m / strict / noupdate
893 log_message = RATE: $sender_rate / $sender_rate_period \
894 (max $sender_rate_limit)
896 [... some other logic and tests...]
898 warn ratelimit = 100 / 5m / strict / per_cmd
899 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
900 (max $sender_rate_limit)
901 condition = ${if le{$sender_rate}{$sender_rate_limit}}
905 6. The variable $max_received_linelength contains the number of bytes in the
906 longest line that was received as part of the message, not counting the
907 line termination character(s).
909 7. Host lists can now include +ignore_defer and +include_defer, analagous to
910 +ignore_unknown and +include_unknown. These options should be used with
911 care, probably only in non-critical host lists such as whitelists.
913 8. There's a new option called queue_only_load_latch, which defaults true.
914 If set false when queue_only_load is greater than zero, Exim re-evaluates
915 the load for each incoming message in an SMTP session. Otherwise, once one
916 message is queued, the remainder are also.
918 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
919 cases when an SMTP session ends without sending QUIT. However, when Exim
920 itself is is bad trouble, such as being unable to write to its log files,
921 this ACL is not run, because it might try to do things (such as write to
922 log files) that make the situation even worse.
924 Like the QUIT ACL, this new ACL is provided to make it possible to gather
925 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
926 modifier is forbidden in this ACL.
928 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
929 to a string that indicates the reason for the termination of the SMTP
930 connection. The possible values are:
932 acl-drop Another ACL issued a "drop" command
933 bad-commands Too many unknown or non-mail commands
934 command-timeout Timeout while reading SMTP commands
935 connection-lost The SMTP connection has been lost
936 data-timeout Timeout while reading message data
937 local-scan-error The local_scan() function crashed
938 local-scan-timeout The local_scan() function timed out
939 signal-exit SIGTERM or SIGINT
940 synchronization-error SMTP synchronization error
941 tls-failed TLS failed to start
943 In most cases when an SMTP connection is closed without having received
944 QUIT, Exim sends an SMTP response message before actually closing the
945 connection. With the exception of acl-drop, the default message can be
946 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
947 "drop" verb in another ACL, it is the message from the other ACL that is
950 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
951 servers with individual queries. This is done by starting the query with
952 "servers=x:y:z;", where each item in the list may take one of two forms:
954 (1) If it is just a host name, the appropriate global option (mysql_servers
955 or pgsql_servers) is searched for a host of the same name, and the
956 remaining parameters (database, user, password) are taken from there.
958 (2) If it contains any slashes, it is taken as a complete parameter set.
960 The list of servers is used in exactly the same was as the global list.
961 Once a connection to a server has happened and a query has been
962 successfully executed, processing of the lookup ceases.
964 This feature is intended for use in master/slave situations where updates
965 are occurring, and one wants to update a master rather than a slave. If the
966 masters are in the list for reading, you might have:
968 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
970 In an updating lookup, you could then write
972 ${lookup mysql{servers=master; UPDATE ...}
974 If, on the other hand, the master is not to be used for reading lookups:
976 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
978 you can still update the master by
980 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
982 11. The message_body_newlines option (default FALSE, for backwards
983 compatibility) can be used to control whether newlines are present in
984 $message_body and $message_body_end. If it is FALSE, they are replaced by
991 1. There is a new log selector called smtp_no_mail, which is not included in
992 the default setting. When it is set, a line is written to the main log
993 whenever an accepted SMTP connection terminates without having issued a
996 2. When an item in a dnslists list is followed by = and & and a list of IP
997 addresses, the behaviour was not clear when the lookup returned more than
998 one IP address. This has been solved by the addition of == and =& for "all"
999 rather than the default "any" matching.
1001 3. Up till now, the only control over which cipher suites GnuTLS uses has been
1002 for the cipher algorithms. New options have been added to allow some of the
1003 other parameters to be varied.
1005 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
1006 set, Exim compiles a runtime option called disable_fsync.
1008 5. There is a new variable called $smtp_count_at_connection_start.
1010 6. There's a new control called no_pipelining.
1012 7. There are two new variables called $sending_ip_address and $sending_port.
1013 These are set whenever an SMTP connection to another host has been set up.
1015 8. The expansion of the helo_data option in the smtp transport now happens
1016 after the connection to the server has been made.
1018 9. There is a new expansion operator ${rfc2047d: that decodes strings that
1019 are encoded as per RFC 2047.
1021 10. There is a new log selector called "pid", which causes the current process
1022 id to be added to every log line, in square brackets, immediately after the
1025 11. Exim has been modified so that it flushes SMTP output before implementing
1026 a delay in an ACL. It also flushes the output before performing a callout,
1027 as this can take a substantial time. These behaviours can be disabled by
1028 obeying control = no_delay_flush or control = no_callout_flush,
1029 respectively, at some earlier stage of the connection.
1031 12. There are two new expansion conditions that iterate over a list. They are
1032 called forany and forall.
1034 13. There's a new global option called dsn_from that can be used to vary the
1035 contents of From: lines in bounces and other automatically generated
1036 messages ("delivery status notifications" - hence the name of the option).
1038 14. The smtp transport has a new option called hosts_avoid_pipelining.
1040 15. By default, exigrep does case-insensitive matches. There is now a -I option
1041 that makes it case-sensitive.
1043 16. A number of new features ("addresses", "map", "filter", and "reduce") have
1044 been added to string expansions to make it easier to process lists of
1045 items, typically addresses.
1047 17. There's a new ACL modifier called "continue". It does nothing of itself,
1048 and processing of the ACL always continues with the next condition or
1049 modifier. It is provided so that the side effects of expanding its argument
1052 18. It is now possible to use newline and other control characters (those with
1053 values less than 32, plus DEL) as separators in lists.
1055 19. The exigrep utility now has a -v option, which inverts the matching
1058 20. The host_find_failed option in the manualroute router can now be set to
1065 No new features were added to 4.66.
1071 No new features were added to 4.65.
1077 1. ACL variables can now be given arbitrary names, as long as they start with
1078 "acl_c" or "acl_m" (for connection variables and message variables), are at
1079 least six characters long, with the sixth character being either a digit or
1082 2. There is a new ACL modifier called log_reject_target. It makes it possible
1083 to specify which logs are used for messages about ACL rejections.
1085 3. There is a new authenticator called "dovecot". This is an interface to the
1086 authentication facility of the Dovecot POP/IMAP server, which can support a
1087 number of authentication methods.
1089 4. The variable $message_headers_raw provides a concatenation of all the
1090 messages's headers without any decoding. This is in contrast to
1091 $message_headers, which does RFC2047 decoding on the header contents.
1093 5. In a DNS black list, if two domain names, comma-separated, are given, the
1094 second is used first to do an initial check, making use of any IP value
1095 restrictions that are set. If there is a match, the first domain is used,
1096 without any IP value restrictions, to get the TXT record.
1098 6. All authenticators now have a server_condition option.
1100 7. There is a new command-line option called -Mset. It is useful only in
1101 conjunction with -be (that is, when testing string expansions). It must be
1102 followed by a message id; Exim loads the given message from its spool
1103 before doing the expansions.
1105 8. Another similar new command-line option is called -bem. It operates like
1106 -be except that it must be followed by the name of a file that contains a
1109 9. When an address is delayed because of a 4xx response to a RCPT command, it
1110 is now the combination of sender and recipient that is delayed in
1111 subsequent queue runs until its retry time is reached.
1113 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1114 shift, have been added to the eval: and eval10: expansion items.
1116 11. The variables $interface_address and $interface_port have been renamed
1117 as $received_ip_address and $received_port, to make it clear that they
1118 relate to message reception rather than delivery. (The old names remain
1119 available for compatibility.)
1121 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1122 to vary the message that is sent when an SMTP command is accepted.
1128 1. There is a new Boolean option called filter_prepend_home for the redirect
1131 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1132 start of receiving a non-SMTP message, before any of the message has been
1135 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1136 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1137 start of the message for an SMTP error code.
1139 4. There is a new parameter for LDAP lookups called "referrals", which takes
1140 one of the settings "follow" (the default) or "nofollow".
1142 5. Version 20070721.2 of exipick now included, offering these new options:
1144 After all other sorting options have bee processed, reverse order
1145 before displaying messages (-R is synonym).
1147 Randomize order of matching messages before displaying.
1149 Instead of displaying the matching messages, display the sum
1151 --sort <variable>[,<variable>...]
1152 Before displaying matching messages, sort the messages according to
1153 each messages value for each variable.
1155 Negate the value for every test (returns inverse output from the
1156 same criteria without --not).
1162 1. The ${readsocket expansion item now supports Internet domain sockets as well
1163 as Unix domain sockets. If the first argument begins "inet:", it must be of
1164 the form "inet:host:port". The port is mandatory; it may be a number or the
1165 name of a TCP port in /etc/services. The host may be a name, or it may be an
1166 IP address. An ip address may optionally be enclosed in square brackets.
1167 This is best for IPv6 addresses. For example:
1169 ${readsocket{inet:[::1]:1234}{<request data>}...
1171 Only a single host name may be given, but if looking it up yield more than
1172 one IP address, they are each tried in turn until a connection is made. Once
1173 a connection has been made, the behaviour is as for ${readsocket with a Unix
1176 2. If a redirect router sets up file or pipe deliveries for more than one
1177 incoming address, and the relevant transport has batch_max set greater than
1178 one, a batch delivery now occurs.
1180 3. The appendfile transport has a new option called maildirfolder_create_regex.
1181 Its value is a regular expression. For a maildir delivery, this is matched
1182 against the maildir directory; if it matches, Exim ensures that a
1183 maildirfolder file is created alongside the new, cur, and tmp directories.
1189 The documentation is up-to-date for the 4.61 release. Major new features since
1190 the 4.60 release are:
1192 . An option called disable_ipv6, to disable the use of IPv6 completely.
1194 . An increase in the number of ACL variables to 20 of each type.
1196 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1197 $2, $3, (though those are still set) because the numeric variables get used
1198 for other things in complicated expansions.
1200 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1202 . It is possible to use setclassresources() on some BSD OS to control the
1203 resources used in pipe deliveries.
1205 . A new ACL modifier called add_header, which can be used with any verb.
1207 . More errors are detectable in retry rules.
1209 There are a number of other additions too.
1215 The documentation is up-to-date for the 4.60 release. Major new features since
1216 the 4.50 release are:
1218 . Support for SQLite.
1220 . Support for IGNOREQUOTA in LMTP.
1222 . Extensions to the "submission mode" features.
1224 . Support for Client SMTP Authorization (CSA).
1226 . Support for ratelimiting hosts and users.
1228 . New expansion items to help with the BATV "prvs" scheme.
1230 . A "match_ip" condition, that matches an IP address against a list.
1232 There are many more minor changes.
git://git.exim.org / exim.git / blob