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. Both GnuTLS and
16 OpenSSL versions are moved to mainline support from 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 OpenSSL 1.1.1 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.
44 12. Expansion item ${authresults {<machine>}} for creating an
45 Authentication-Results: header.
47 13. EXPERIMENTAL_ARC. See the experimental.spec file.
49 14: A dane:fail event, intended to facilitate reporting.
51 15. "Lightweight" support for Redis Cluster. Requires redis_servers list to
52 contain all the servers in the cluster, all of which must be reachable from
53 the running exim instance. If the cluster has master/slave replication, the
54 list must contain all the master and slave servers.
60 1. PKG_CONFIG_PATH can now be set in Local/Makefile;
61 wildcards will be expanded, values are collapsed.
63 2. The ${readsocket } expansion now takes an option to not shutdown the
64 connection after sending the query string. The default remains to do so.
66 3. An smtp transport option "hosts_noproxy_tls" to control whether multiple
67 deliveries on a single TCP connection can maintain a TLS connection
68 open. By default disabled for all hosts, doing so saves the cost of
69 making new TLS sessions, at the cost of having to proxy the data via
70 another process. Logging is also affected.
72 4. A malware connection type for the FPSCAND protocol.
74 5. An option for recipient verify callouts to hold the connection open for
75 further recipients and for delivery.
77 6. The reproducible build $SOURCE_DATE_EPOCH environment variable is now
80 7. Optionally, an alternate format for spool data-files which matches the
81 wire format - meaning more efficient reception and transmission (at the
82 cost of difficulty with standard Unix tools). Only used for messages
83 received using the ESMTP CHUNKING option, and when a new main-section
84 option "spool_wireformat" (false by default) is set.
86 8. New main configuration option "commandline_checks_require_admin" to
87 restrict who can use various introspection options.
89 9. New option modifier "no_check" for quota and quota_filecount
92 10. Variable $smtp_command_history returning a comma-sep list of recent
95 11. Millisecond timetamps in logs, on log_selector "millisec". Also affects
96 log elements QT, DT and D, and timstamps in debug output.
98 12. TCP Fast Open logging. As a server, logs when the SMTP banner was sent
99 while still in SYN_RECV state; as a client logs when the connection
100 is opened with a TFO cookie.
102 13. DKIM support for multiple signing, by domain and/or key-selector.
103 DKIM support for multiple hashes, and for alternate-identity tags.
104 Builtin macro with default list of signed headers.
105 Better syntax for specifying oversigning.
106 The DKIM ACL can override verification status, and status is visible in
109 14. Exipick understands -C|--config for an alternative Exim
112 15. TCP Fast Open used, with data-on-SYN, for client SMTP via SOCKS5 proxy,
113 for ${readsocket } expansions, and for ClamAV.
115 16. The "-be" expansion test mode now supports macros. Macros are expanded
116 in test lines, and new macros can be defined.
118 17. Support for server-side dual-certificate-stacks (eg. RSA + ECDSA).
124 1. Allow relative config file names for ".include"
126 2. A main-section config option "debug_store" to control the checks on
127 variable locations during store-reset. Normally false but can be enabled
128 when a memory corrution issue is suspected on a production system.
134 1. The new perl_taintmode option allows to run the embedded perl
135 interpreter in taint mode.
137 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
139 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
142 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
143 N can be 224, 256 (default), 384, 512.
144 With GnuTLS 3.5.0 or later, only.
146 5. Facility for named queues: A command-line argument can specify
147 the queue name for a queue operation, and an ACL modifier can set
148 the queue to be used for a message. A $queue_name variable gives
151 6. New expansion operators base32/base32d.
153 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
154 performance increase and network load decrease. Main config option
155 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
158 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
160 9. Expansion operator escape8bit, like escape but not touching newline etc..
162 10. Feature macros, generated from compile options. All start with "_HAVE_"
163 and go on with some roughly recognisable name. Driver macros, for
164 router, transport and authentication drivers; names starting with "_DRIVER_".
165 Option macros, for each configuration-file option; all start with "_OPT_".
166 Use the "-bP macros" command-line option to see what is present.
168 11. Integer values for options can take a "G" multiplier.
170 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
171 returns from the target back to the initiator, rather than spooling the
174 13. New built-in constants available for tls_dhparam and default changed.
176 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
177 out copies of the message spool files for use by 3rd-party scanners.
179 15. A new option on the smtp transport, hosts_try_fastopen. If the system
180 supports it (on Linux it must be enabled in the kernel by the sysadmin)
181 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
182 but it permits a peer that also supports the facility to send its SMTP
183 banner immediately after the SYN,ACK segment rather then waiting for
184 another ACK - so saving up to one roundtrip time. Because it requires
185 previous communication with the peer (we save a cookie from it) this
186 will only become active on frequently-contacted destinations.
188 16. A new syslog_pid option to suppress PID duplication in syslog lines.
194 1. The ACL conditions regex and mime_regex now capture substrings
195 into numeric variables $regex1 to 9, like the "match" expansion condition.
197 2. New $callout_address variable records the address used for a spam=,
198 malware= or verify= callout.
200 3. Transports now take a "max_parallel" option, to limit concurrency.
202 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
203 The latter expands to a 8-element colon-sep set of hex digits including
204 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
205 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
206 The former operator strips leading zeroes and collapses the longest
207 set of 0-groups to a double-colon.
209 5. New "-bP config" support, to dump the effective configuration.
211 6. New $dkim_key_length variable.
213 7. New base64d and base64 expansion items (the existing str2b64 being a
214 synonym of the latter). Add support in base64 for certificates.
216 8. New main configuration option "bounce_return_linesize_limit" to
217 avoid oversize bodies in bounces. The default value matches RFC
220 9. New $initial_cwd expansion variable.
226 1. Support for using the system standard CA bundle.
228 2. New expansion items $config_file, $config_dir, containing the file
229 and directory name of the main configuration file. Also $exim_version.
231 3. New "malware=" support for Avast.
233 4. New "spam=" variant option for Rspamd.
235 5. Assorted options on malware= and spam= scanners.
237 6. A command-line option to write a comment into the logfile.
239 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
240 be configured to make connections via socks5 proxies.
242 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
243 the transmission of UTF-8 envelope addresses.
245 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
246 used encoding of Maildir folder names.
248 10. A logging option for slow DNS lookups.
250 11. New ${env {<variable>}} expansion.
252 12. A non-SMTP authenticator using information from TLS client certificates.
254 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
255 Patch originally by Wolfgang Breyha.
257 14. Main option "dns_trust_aa" for trusting your local nameserver at the
258 same level as DNSSEC.
264 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
265 DANE SMTP draft to assess a secure chain of trust of the certificate
266 used to establish the TLS connection based on a TLSA record in the
267 domain of the sender.
269 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
270 and several new events have been created. The reason is because it has
271 been expanded beyond just firing events during the transport phase. Any
272 existing TPDA transport options will have to be rewritten to use a new
273 $event_name expansion variable in a condition. Refer to the
274 experimental-spec.txt for details and examples.
276 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
277 server certs used for TLS match the result of the MX lookup. It does
278 not use the same mechanism as DANE.
288 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
289 configured to expect an initial header from a proxy that will make the
290 actual external source IP:host be used in exim instead of the IP of the
291 proxy that is connecting to it.
293 2. New verify option header_names_ascii, which will check to make sure
294 there are no non-ASCII characters in header names. Exim itself handles
295 those non-ASCII characters, but downstream apps may not, so Exim can
296 detect and reject if those characters are present.
298 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
299 codepoints with valid ones.
301 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
302 command line and matching a regex against the return data for trigger
303 and a second regex to extract malware_name. The mail spoolfile name can
304 be included in the command line.
306 5. The smtp transport now supports options "tls_verify_hosts" and
307 "tls_try_verify_hosts". If either is set the certificate verification
308 is split from the encryption operation. The default remains that a failed
309 verification cancels the encryption.
311 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
312 lookup can now set a list of servers to use that is different from the
315 7. New command-line option -C for exiqgrep to specify alternate exim.conf
316 file when searching the queue.
318 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
320 9. Support for DNSSEC on outbound connections.
322 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
323 "certextract" to extract fields from them. Hash operators md5 and sha1
324 work over them for generating fingerprints, and a new sha256 operator
327 11. PRDR is now supported dy default.
329 12. OCSP stapling is now supported by default.
331 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
332 Delivery Status Notification messages in MIME format, and negotiate
333 DSN features per RFC 3461.
339 1. New command-line option -bI:sieve will list all supported sieve extensions
340 of this Exim build on standard output, one per line.
341 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
342 query this to establish the correct list to include in the protocol's
343 SIEVE capability line.
345 2. If the -n option is combined with the -bP option, then the name of an
346 emitted option is not output, only the value (if visible to you).
347 For instance, "exim -n -bP pid_file_path" should just emit a pathname
348 followed by a newline, and no other text.
350 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
351 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
352 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
353 acceptable for security. (Option accepted but ignored if using OpenSSL).
354 Defaults to 1024, the old value. May be lowered only to 512, or raised as
355 far as you like. Raising this may hinder TLS interoperability with other
356 sites and is not currently recommended. Lowering this will permit you to
357 establish a TLS session which is not as secure as you might like.
359 Unless you really know what you are doing, leave it alone.
361 4. If not built with DISABLE_DNSSEC, Exim now has the main option
362 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
363 to send the DO flag to your recursive resolver. If you have a recursive
364 resolver, which can set the Authenticated Data (AD) flag in results, Exim
365 can now detect this. Exim does not perform validation itself, instead
366 relying upon a trusted path to the resolver.
368 Current status: work-in-progress; $sender_host_dnssec variable added.
370 5. DSCP support for outbound connections: on a transport using the smtp driver,
371 set "dscp = ef", for instance, to cause the connections to have the relevant
372 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
374 Similarly for inbound connections, there is a new control modifier, dscp,
375 so "warn control = dscp/ef" in the connect ACL, or after authentication.
377 Supported values depend upon system libraries. "exim -bI:dscp" to list the
378 ones Exim knows of. You can also set a raw number 0..0x3F.
380 6. The -G command-line flag is no longer ignored; it is now equivalent to an
381 ACL setting "control = suppress_local_fixups". The -L command-line flag
382 is now accepted and forces use of syslog, with the provided tag as the
383 process name. A few other flags used by Sendmail are now accepted and
386 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
387 ACL modifier; works for single-recipient mails which are received on and
388 deliverable via SMTP. Using the connection made for a recipient verify,
389 if requested before the verify, or a new one made for the purpose while
390 the inbound connection is still active. The bulk of the mail item is copied
391 direct from the inbound socket to the outbound (as well as the spool file).
392 When the source notifies the end of data, the data acceptance by the destination
393 is negotiated before the acceptance is sent to the source. If the destination
394 does not accept the mail item, for example due to content-scanning, the item
395 is not accepted from the source and therefore there is no need to generate
396 a bounce mail. This is of benefit when providing a secondary-MX service.
397 The downside is that delays are under the control of the ultimate destination
400 The Received-by: header on items delivered by cutthrough is generated
401 early in reception rather than at the end; this will affect any timestamp
402 included. The log line showing delivery is recorded before that showing
403 reception; it uses a new ">>" tag instead of "=>".
405 To support the feature, verify-callout connections can now use ESMTP and TLS.
406 The usual smtp transport options are honoured, plus a (new, default everything)
407 hosts_verify_avoid_tls.
409 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
410 for specific access to the information for each connection. The old names
411 are present for now but deprecated.
413 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
415 8. New expansion operators ${listnamed:name} to get the content of a named list
416 and ${listcount:string} to count the items in a list.
418 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
419 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
420 modules. For some situations this is desirable, but we expect admin in
421 those situations to know they want the feature. More commonly, it means
422 that GUI user modules get loaded and are broken by the setuid Exim being
423 unable to access files specified in environment variables and passed
424 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
425 unless this new option is set.
427 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
428 so have also added a build option which can be used to build Exim with GnuTLS
429 but without trying to use any kind of PKCS11 support. Uncomment this in the
432 AVOID_GNUTLS_PKCS11=yes
434 10. The "acl = name" condition on an ACL now supports optional arguments.
435 New expansion item "${acl {name}{arg}...}" and expansion condition
436 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
437 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
438 Variable $acl_narg contains the number of arguments. If the ACL sets
439 a "message =" value this becomes the result of the expansion item,
440 or the value of $value for the expansion condition. If the ACL returns
441 accept the expansion condition is true; if reject, false. A defer
442 return results in a forced fail.
444 11. Routers and transports can now have multiple headers_add and headers_remove
445 option lines. The concatenated list is used.
447 12. New ACL modifier "remove_header" can remove headers before message gets
448 handled by routers/transports.
450 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
451 "aaaa" and "a" lookups is done and the full set of results returned.
453 14. New expansion variable $headers_added with content from ACL add_header
454 modifier (but not yet added to message).
456 15. New 8bitmime status logging option for received messages. Log field "M8S".
458 16. New authenticated_sender logging option, adding to log field "A".
460 17. New expansion variables $router_name and $transport_name. Useful
461 particularly for debug_print as -bt command-line option does not
462 require privilege whereas -d does.
464 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
465 proposed extension to SMTP from Eric Hall.
467 19. The pipe transport has gained the force_command option, to allow
468 decorating commands from user .forward pipe aliases with prefix
469 wrappers, for instance.
471 20. Callout connections can now AUTH; the same controls as normal delivery
474 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
475 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
476 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
477 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
478 dmarc_status. It adds new control flags dmarc_disable_verify and
479 dmarc_enable_forensic. The default for the dmarc_tld_file option is
480 "/etc/exim/opendmarc.tlds" and can be changed via EDITME.
482 22. Add expansion variable $authenticated_fail_id, which is the username
483 provided to the authentication method which failed. It is available
484 for use in subsequent ACL processing (typically quit or notquit ACLs).
486 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
489 24. New ${hexquote:..string..} expansion operator converts non-printable
490 characters in the string to \xNN form.
492 25. Experimental TPDA (Transport Post Delivery Action) function added.
493 Patch provided by Axel Rau.
495 26. Experimental Redis lookup added. Patch provided by Warren Baker.
501 1. New authenticator driver, "gsasl". Server-only (at present).
502 This is a SASL interface, licensed under GPL, which can be found at
503 http://www.gnu.org/software/gsasl/.
504 This system does not provide sources of data for authentication, so
505 careful use needs to be made of the conditions in Exim.
507 2. New authenticator driver, "heimdal_gssapi". Server-only.
508 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
509 is no longer honoured for setuid programs by Heimdal. Use the
510 "server_keytab" option to point to the keytab.
512 3. The "pkg-config" system can now be used when building Exim to reference
513 cflags and library information for lookups and authenticators, rather
514 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
515 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
516 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
518 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
519 find the headers and libraries for PCRE.
521 4. New expansion variable $tls_bits.
523 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
524 be joined together with ASCII NUL characters to construct the key to pass
525 into the DBM library. Can be used with gsasl to access sasldb2 files as
528 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
530 Avoid release 1.0.1a if you can. Note that the default value of
531 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
532 increased susceptibility to attack. This may still have interoperability
533 implications for very old clients (see version 4.31 change 37) but
534 administrators can choose to make the trade-off themselves and restore
535 compatibility at the cost of session security.
537 7. Use of the new expansion variable $tls_sni in the main configuration option
538 tls_certificate will cause Exim to re-expand the option, if the client
539 sends the TLS Server Name Indication extension, to permit choosing a
540 different certificate; tls_privatekey will also be re-expanded. You must
541 still set these options to expand to valid files when $tls_sni is not set.
543 The SMTP Transport has gained the option tls_sni, which will set a hostname
544 for outbound TLS sessions, and set $tls_sni too.
546 A new log_selector, +tls_sni, has been added, to log received SNI values
547 for Exim as a server.
549 8. The existing "accept_8bitmime" option now defaults to true. This means
550 that Exim is deliberately not strictly RFC compliant. We're following
551 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
552 Those who disagree, or know that they are talking to mail servers that,
553 even today, are not 8-bit clean, need to turn off this option.
555 9. Exim can now be started with -bw (with an optional timeout, given as
556 -bw<timespec>). With this, stdin at startup is a socket that is
557 already listening for connections. This has a more modern name of
558 "socket activation", but forcing the activated socket to fd 0. We're
559 interested in adding more support for modern variants.
561 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
562 for numbers indicates multiplication by 1024^3.
564 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
565 gnutls_require_mac & gnutls_require_protocols are no longer supported.
566 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
567 string, documentation for which is at:
568 http://www.gnutls.org/manual/html_node/Priority-Strings.html
570 SNI support has been added to Exim's GnuTLS integration too.
572 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
573 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
575 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
576 is now available. If the contents of the file are valid, then Exim will
577 send that back in response to a TLS status request; this is OCSP Stapling.
578 Exim will not maintain the contents of the file in any way: administrators
579 are responsible for ensuring that it is up-to-date.
581 See "experimental-spec.txt" for more details.
583 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
584 identically to TXT record lookups.
586 14. New expansion variable $tod_epoch_l for higher-precision time.
588 15. New global option tls_dh_max_bits, defaulting to current value of NSS
589 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
590 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
592 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
593 Option can now be a path or an identifier for a standard prime.
594 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
595 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
598 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
599 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
600 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
606 1. New options for the ratelimit ACL condition: /count= and /unique=.
607 The /noupdate option has been replaced by a /readonly option.
609 2. The SMTP transport's protocol option may now be set to "smtps", to
610 use SSL-on-connect outbound.
612 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
613 there is a problem talking to the AV scanner, or the AV scanner running.
615 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
616 and check if the search item is a member of the list. This does not
617 support named lists, but does subject the list part to string expansion.
619 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
620 built, Exim no longer performs string expansion on the second string of
621 the match_* expansion conditions: "match_address", "match_domain",
622 "match_ip" & "match_local_part". Named lists can still be used.
628 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
629 or off in the resolver library.
635 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
636 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
637 libraries. The following global options have been added in support of
638 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
639 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
641 2. The pipe transport now takes a boolean option, "freeze_signal", default
642 false. When true, if the external delivery command exits on a signal then
643 Exim will freeze the message in the queue, instead of generating a bounce.
645 3. Log filenames may now use %M as an escape, instead of %D (still available).
646 The %M pattern expands to yyyymm, providing month-level resolution.
648 4. The $message_linecount variable is now updated for the maildir_tag option,
649 in the same way as $message_size, to reflect the real number of lines,
650 including any header additions or removals from transport.
652 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
653 Exim now selects entries randomly, to better scale in a cluster setup.
659 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
660 the flaw permitted the Exim run-time user to cause root to append to
661 arbitrary files of the attacker's choosing, with the content based
662 on content supplied by the attacker.
664 2. Exim now supports loading some lookup types at run-time, using your
665 platform's dlopen() functionality. This has limited platform support
666 and the intention is not to support every variant, it's limited to
667 dlopen(). This permits the main Exim binary to not be linked against
668 all the libraries needed for all the lookup types.
674 NOTE: this version is not guaranteed backwards-compatible, please read the
675 items below carefully
677 1. A new main configuration option, "openssl_options", is available if Exim
678 is built with SSL support provided by OpenSSL. The option allows
679 administrators to specify OpenSSL options to be used on connections;
680 typically this is to set bug compatibility features which the OpenSSL
681 developers have not enabled by default. There may be security
682 consequences for certain options, so these should not be changed
685 2. A new pipe transport option, "permit_coredumps", may help with problem
686 diagnosis in some scenarios. Note that Exim is typically installed as
687 a setuid binary, which on most OSes will inhibit coredumps by default,
688 so that safety mechanism would have to be overridden for this option to
689 be able to take effect.
691 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
692 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
693 Note that this switches Exim to use a new API ("INSTREAM") and a future
694 release of ClamAV will remove support for the old API ("STREAM").
696 The av_scanner option, when set to "clamd", now takes an optional third
697 part, "local", which causes Exim to pass a filename to ClamAV instead of
698 the file content. This is the same behaviour as when clamd is pointed at
699 a Unix-domain socket. For example:
701 av_scanner = clamd:192.0.2.3 1234:local
703 ClamAV's ExtendedDetectionInfo response format is now handled.
705 4. There is now a -bmalware option, restricted to admin users. This option
706 takes one parameter, a filename, and scans that file with Exim's
707 malware-scanning framework. This is intended purely as a debugging aid
708 to ensure that Exim's scanning is working, not to replace other tools.
709 Note that the ACL framework is not invoked, so if av_scanner references
710 ACL variables without a fallback then this will fail.
712 5. There is a new expansion operator, "reverse_ip", which will reverse IP
713 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
715 ${reverse_ip:192.0.2.4}
717 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
718 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
720 6. There is a new ACL control called "debug", to enable debug logging.
721 This allows selective logging of certain incoming transactions within
722 production environments, with some care. It takes two options, "tag"
723 and "opts"; "tag" is included in the filename of the log and "opts"
724 is used as per the -d<options> command-line option. Examples, which
725 don't all make sense in all contexts:
728 control = debug/tag=.$sender_host_address
729 control = debug/opts=+expand+acl
730 control = debug/tag=.$message_exim_id/opts=+expand
732 7. It has always been implicit in the design and the documentation that
733 "the Exim user" is not root. src/EDITME said that using root was
734 "very strongly discouraged". This is not enough to keep people from
735 shooting themselves in the foot in days when many don't configure Exim
736 themselves but via package build managers. The security consequences of
737 running various bits of network code are severe if there should be bugs in
738 them. As such, the Exim user may no longer be root. If configured
739 statically, Exim will refuse to build. If configured as ref:user then Exim
740 will exit shortly after start-up. If you must shoot yourself in the foot,
741 then henceforth you will have to maintain your own local patches to strip
744 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
745 condition logic to determine truth/failure and will fail to expand many
746 strings, bool_lax{} uses the router condition logic, where most strings
748 Note: bool{00} is false, bool_lax{00} is true.
750 9. Routers now support multiple "condition" tests.
752 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
753 Setting this allows an admin to define which entry in the tcpwrappers
754 config file will be used to control access to the daemon. This option
755 is only available when Exim is built with USE_TCP_WRAPPERS. The
756 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
759 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
760 the Exim run-time user, instead of root.
762 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
763 is forced on. This is mitigated by the new build option
764 TRUSTED_CONFIG_LIST which defines a list of configuration files which
765 are trusted; one per line. If a config file is owned by root and matches
766 a pathname in the list, then it may be invoked by the Exim build-time
767 user without Exim relinquishing root privileges.
769 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
770 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
771 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
772 include the main config. As a transition mechanism, we are temporarily
773 providing a work-around: the new build option WHITELIST_D_MACROS provides
774 a colon-separated list of macro names which may be overridden by the Exim
775 run-time user. The values of these macros are constrained to the regex
776 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
782 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
783 writable, the other to locking of MBX folders (not mbox).
785 2. MySQL stored procedures are now supported.
787 3. The dkim_domain transport option is now a list, not a single string, and
788 messages will be signed for each element in the list (discarding
791 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
792 in the presence of multiple character strings within the RR. Prior to 4.70,
793 only the first string would be returned. The dnsdb lookup now, by default,
794 preserves the pre-4.70 semantics, but also now takes an extended output
795 separator specification. The separator can be followed by a semicolon, to
796 concatenate the individual text strings together with no join character,
797 or by a comma and a second separator character, in which case the text
798 strings within a TXT record are joined on that second character.
799 Administrators are reminded that DNS provides no ordering guarantees
800 between multiple records in an RRset. For example:
802 foo.example. IN TXT "a" "b" "c"
803 foo.example. IN TXT "d" "e" "f"
805 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
806 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
807 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
813 1. Native DKIM support without an external library.
814 (Note that if no action to prevent it is taken, a straight upgrade will
815 result in DKIM verification of all signed incoming emails. See spec
816 for details on conditionally disabling)
818 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
820 3. There is now a bool{} expansion condition which maps certain strings to
821 true/false condition values (most likely of use in conjunction with the
822 and{} expansion operator).
824 4. The $spam_score, $spam_bar and $spam_report variables are now available
827 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
828 options, provided that Exim is invoked by an admin_user.
830 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
831 which increases compatibility with older clients at the cost of decreased
832 security. Don't set this unless you need to support such clients.
834 7. There is a new expansion operator, ${randint:...} which will produce a
835 "random" number less than the supplied integer. This randomness is
836 not guaranteed to be cryptographically strong, but depending upon how
837 Exim was built may be better than the most naive schemes.
839 8. Exim now explicitly ensures that SHA256 is available when linked against
842 9. The transport_filter_timeout option now applies to SMTP transports too.
848 1. Preliminary DKIM support in Experimental.
854 1. The body_linecount and body_zerocount C variables are now exported in the
857 2. When a dnslists lookup succeeds, the key that was looked up is now placed
858 in $dnslist_matched. When the key is an IP address, it is not reversed in
859 this variable (though it is, of course, in the actual lookup). In simple
862 deny dnslists = spamhaus.example
864 the key is also available in another variable (in this case,
865 $sender_host_address). In more complicated cases, however, this is not
866 true. For example, using a data lookup might generate a dnslists lookup
869 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
871 If this condition succeeds, the value in $dnslist_matched might be
872 192.168.6.7 (for example).
874 3. Authenticators now have a client_condition option. When Exim is running as
875 a client, it skips an authenticator whose client_condition expansion yields
876 "0", "no", or "false". This can be used, for example, to skip plain text
877 authenticators when the connection is not encrypted by a setting such as:
879 client_condition = ${if !eq{$tls_cipher}{}}
881 Note that the 4.67 documentation states that $tls_cipher contains the
882 cipher used for incoming messages. In fact, during SMTP delivery, it
883 contains the cipher used for the delivery. The same is true for
886 4. There is now a -Mvc <message-id> option, which outputs a copy of the
887 message to the standard output, in RFC 2822 format. The option can be used
888 only by an admin user.
890 5. There is now a /noupdate option for the ratelimit ACL condition. It
891 computes the rate and checks the limit as normal, but it does not update
892 the saved data. This means that, in relevant ACLs, it is possible to lookup
893 the existence of a specified (or auto-generated) ratelimit key without
894 incrementing the ratelimit counter for that key.
896 In order for this to be useful, another ACL entry must set the rate
897 for the same key somewhere (otherwise it will always be zero).
902 # Read the rate; if it doesn't exist or is below the maximum
904 deny ratelimit = 100 / 5m / strict / noupdate
905 log_message = RATE: $sender_rate / $sender_rate_period \
906 (max $sender_rate_limit)
908 [... some other logic and tests...]
910 warn ratelimit = 100 / 5m / strict / per_cmd
911 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
912 (max $sender_rate_limit)
913 condition = ${if le{$sender_rate}{$sender_rate_limit}}
917 6. The variable $max_received_linelength contains the number of bytes in the
918 longest line that was received as part of the message, not counting the
919 line termination character(s).
921 7. Host lists can now include +ignore_defer and +include_defer, analagous to
922 +ignore_unknown and +include_unknown. These options should be used with
923 care, probably only in non-critical host lists such as whitelists.
925 8. There's a new option called queue_only_load_latch, which defaults true.
926 If set false when queue_only_load is greater than zero, Exim re-evaluates
927 the load for each incoming message in an SMTP session. Otherwise, once one
928 message is queued, the remainder are also.
930 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
931 cases when an SMTP session ends without sending QUIT. However, when Exim
932 itself is is bad trouble, such as being unable to write to its log files,
933 this ACL is not run, because it might try to do things (such as write to
934 log files) that make the situation even worse.
936 Like the QUIT ACL, this new ACL is provided to make it possible to gather
937 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
938 modifier is forbidden in this ACL.
940 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
941 to a string that indicates the reason for the termination of the SMTP
942 connection. The possible values are:
944 acl-drop Another ACL issued a "drop" command
945 bad-commands Too many unknown or non-mail commands
946 command-timeout Timeout while reading SMTP commands
947 connection-lost The SMTP connection has been lost
948 data-timeout Timeout while reading message data
949 local-scan-error The local_scan() function crashed
950 local-scan-timeout The local_scan() function timed out
951 signal-exit SIGTERM or SIGINT
952 synchronization-error SMTP synchronization error
953 tls-failed TLS failed to start
955 In most cases when an SMTP connection is closed without having received
956 QUIT, Exim sends an SMTP response message before actually closing the
957 connection. With the exception of acl-drop, the default message can be
958 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
959 "drop" verb in another ACL, it is the message from the other ACL that is
962 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
963 servers with individual queries. This is done by starting the query with
964 "servers=x:y:z;", where each item in the list may take one of two forms:
966 (1) If it is just a host name, the appropriate global option (mysql_servers
967 or pgsql_servers) is searched for a host of the same name, and the
968 remaining parameters (database, user, password) are taken from there.
970 (2) If it contains any slashes, it is taken as a complete parameter set.
972 The list of servers is used in exactly the same was as the global list.
973 Once a connection to a server has happened and a query has been
974 successfully executed, processing of the lookup ceases.
976 This feature is intended for use in master/slave situations where updates
977 are occurring, and one wants to update a master rather than a slave. If the
978 masters are in the list for reading, you might have:
980 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
982 In an updating lookup, you could then write
984 ${lookup mysql{servers=master; UPDATE ...}
986 If, on the other hand, the master is not to be used for reading lookups:
988 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
990 you can still update the master by
992 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
994 11. The message_body_newlines option (default FALSE, for backwards
995 compatibility) can be used to control whether newlines are present in
996 $message_body and $message_body_end. If it is FALSE, they are replaced by
1003 1. There is a new log selector called smtp_no_mail, which is not included in
1004 the default setting. When it is set, a line is written to the main log
1005 whenever an accepted SMTP connection terminates without having issued a
1008 2. When an item in a dnslists list is followed by = and & and a list of IP
1009 addresses, the behaviour was not clear when the lookup returned more than
1010 one IP address. This has been solved by the addition of == and =& for "all"
1011 rather than the default "any" matching.
1013 3. Up till now, the only control over which cipher suites GnuTLS uses has been
1014 for the cipher algorithms. New options have been added to allow some of the
1015 other parameters to be varied.
1017 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
1018 set, Exim compiles a runtime option called disable_fsync.
1020 5. There is a new variable called $smtp_count_at_connection_start.
1022 6. There's a new control called no_pipelining.
1024 7. There are two new variables called $sending_ip_address and $sending_port.
1025 These are set whenever an SMTP connection to another host has been set up.
1027 8. The expansion of the helo_data option in the smtp transport now happens
1028 after the connection to the server has been made.
1030 9. There is a new expansion operator ${rfc2047d: that decodes strings that
1031 are encoded as per RFC 2047.
1033 10. There is a new log selector called "pid", which causes the current process
1034 id to be added to every log line, in square brackets, immediately after the
1037 11. Exim has been modified so that it flushes SMTP output before implementing
1038 a delay in an ACL. It also flushes the output before performing a callout,
1039 as this can take a substantial time. These behaviours can be disabled by
1040 obeying control = no_delay_flush or control = no_callout_flush,
1041 respectively, at some earlier stage of the connection.
1043 12. There are two new expansion conditions that iterate over a list. They are
1044 called forany and forall.
1046 13. There's a new global option called dsn_from that can be used to vary the
1047 contents of From: lines in bounces and other automatically generated
1048 messages ("delivery status notifications" - hence the name of the option).
1050 14. The smtp transport has a new option called hosts_avoid_pipelining.
1052 15. By default, exigrep does case-insensitive matches. There is now a -I option
1053 that makes it case-sensitive.
1055 16. A number of new features ("addresses", "map", "filter", and "reduce") have
1056 been added to string expansions to make it easier to process lists of
1057 items, typically addresses.
1059 17. There's a new ACL modifier called "continue". It does nothing of itself,
1060 and processing of the ACL always continues with the next condition or
1061 modifier. It is provided so that the side effects of expanding its argument
1064 18. It is now possible to use newline and other control characters (those with
1065 values less than 32, plus DEL) as separators in lists.
1067 19. The exigrep utility now has a -v option, which inverts the matching
1070 20. The host_find_failed option in the manualroute router can now be set to
1077 No new features were added to 4.66.
1083 No new features were added to 4.65.
1089 1. ACL variables can now be given arbitrary names, as long as they start with
1090 "acl_c" or "acl_m" (for connection variables and message variables), are at
1091 least six characters long, with the sixth character being either a digit or
1094 2. There is a new ACL modifier called log_reject_target. It makes it possible
1095 to specify which logs are used for messages about ACL rejections.
1097 3. There is a new authenticator called "dovecot". This is an interface to the
1098 authentication facility of the Dovecot POP/IMAP server, which can support a
1099 number of authentication methods.
1101 4. The variable $message_headers_raw provides a concatenation of all the
1102 messages's headers without any decoding. This is in contrast to
1103 $message_headers, which does RFC2047 decoding on the header contents.
1105 5. In a DNS black list, if two domain names, comma-separated, are given, the
1106 second is used first to do an initial check, making use of any IP value
1107 restrictions that are set. If there is a match, the first domain is used,
1108 without any IP value restrictions, to get the TXT record.
1110 6. All authenticators now have a server_condition option.
1112 7. There is a new command-line option called -Mset. It is useful only in
1113 conjunction with -be (that is, when testing string expansions). It must be
1114 followed by a message id; Exim loads the given message from its spool
1115 before doing the expansions.
1117 8. Another similar new command-line option is called -bem. It operates like
1118 -be except that it must be followed by the name of a file that contains a
1121 9. When an address is delayed because of a 4xx response to a RCPT command, it
1122 is now the combination of sender and recipient that is delayed in
1123 subsequent queue runs until its retry time is reached.
1125 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1126 shift, have been added to the eval: and eval10: expansion items.
1128 11. The variables $interface_address and $interface_port have been renamed
1129 as $received_ip_address and $received_port, to make it clear that they
1130 relate to message reception rather than delivery. (The old names remain
1131 available for compatibility.)
1133 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1134 to vary the message that is sent when an SMTP command is accepted.
1140 1. There is a new Boolean option called filter_prepend_home for the redirect
1143 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1144 start of receiving a non-SMTP message, before any of the message has been
1147 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1148 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1149 start of the message for an SMTP error code.
1151 4. There is a new parameter for LDAP lookups called "referrals", which takes
1152 one of the settings "follow" (the default) or "nofollow".
1154 5. Version 20070721.2 of exipick now included, offering these new options:
1156 After all other sorting options have bee processed, reverse order
1157 before displaying messages (-R is synonym).
1159 Randomize order of matching messages before displaying.
1161 Instead of displaying the matching messages, display the sum
1163 --sort <variable>[,<variable>...]
1164 Before displaying matching messages, sort the messages according to
1165 each messages value for each variable.
1167 Negate the value for every test (returns inverse output from the
1168 same criteria without --not).
1174 1. The ${readsocket expansion item now supports Internet domain sockets as well
1175 as Unix domain sockets. If the first argument begins "inet:", it must be of
1176 the form "inet:host:port". The port is mandatory; it may be a number or the
1177 name of a TCP port in /etc/services. The host may be a name, or it may be an
1178 IP address. An ip address may optionally be enclosed in square brackets.
1179 This is best for IPv6 addresses. For example:
1181 ${readsocket{inet:[::1]:1234}{<request data>}...
1183 Only a single host name may be given, but if looking it up yield more than
1184 one IP address, they are each tried in turn until a connection is made. Once
1185 a connection has been made, the behaviour is as for ${readsocket with a Unix
1188 2. If a redirect router sets up file or pipe deliveries for more than one
1189 incoming address, and the relevant transport has batch_max set greater than
1190 one, a batch delivery now occurs.
1192 3. The appendfile transport has a new option called maildirfolder_create_regex.
1193 Its value is a regular expression. For a maildir delivery, this is matched
1194 against the maildir directory; if it matches, Exim ensures that a
1195 maildirfolder file is created alongside the new, cur, and tmp directories.
1201 The documentation is up-to-date for the 4.61 release. Major new features since
1202 the 4.60 release are:
1204 . An option called disable_ipv6, to disable the use of IPv6 completely.
1206 . An increase in the number of ACL variables to 20 of each type.
1208 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1209 $2, $3, (though those are still set) because the numeric variables get used
1210 for other things in complicated expansions.
1212 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1214 . It is possible to use setclassresources() on some BSD OS to control the
1215 resources used in pipe deliveries.
1217 . A new ACL modifier called add_header, which can be used with any verb.
1219 . More errors are detectable in retry rules.
1221 There are a number of other additions too.
1227 The documentation is up-to-date for the 4.60 release. Major new features since
1228 the 4.50 release are:
1230 . Support for SQLite.
1232 . Support for IGNOREQUOTA in LMTP.
1234 . Extensions to the "submission mode" features.
1236 . Support for Client SMTP Authorization (CSA).
1238 . Support for ratelimiting hosts and users.
1240 . New expansion items to help with the BATV "prvs" scheme.
1242 . A "match_ip" condition, that matches an IP address against a list.
1244 There are many more minor changes.
git://git.exim.org / exim.git / blob