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. ${l_header:<name>} and ${l_h:<name>} expansion items, giving a colon-sep
13 list when there are multiple headers having a given name. This matters
14 when individual headers are wrapped onto multiple lines; with previous
15 facilities hard to parse.
17 2. The ${readsocket } expansion item now takes a "tls" option, doing the
20 3. EXPERIMENTAL_REQUIRETLS. See the experimental.spec file.
22 4. If built with SUPPORT_I18N a "utf8_downconvert" option on the smtp transport.
24 5. A "pipelining" log_selector.
29 1. Dual-certificate stacks on servers now support OCSP stapling, under GnuTLS
30 version 3.5.6 or later.
32 2. DANE is now supported under GnuTLS version 3.0.0 or later. Both GnuTLS and
33 OpenSSL versions are moved to mainline support from Experimental.
34 New SMTP transport option "dane_require_tls_ciphers".
36 3. Feature macros for the compiled-in set of malware scanner interfaces.
38 4. SPF support is promoted from Experimental to mainline status. The template
39 src/EDITME makefile does not enable its inclusion.
41 5. Logging control for DKIM verification. The existing DKIM log line is
42 controlled by a "dkim_verbose" selector which is _not_ enabled by default.
43 A new tag "DKIM=<domain>" is added to <= lines by default, controlled by
44 a "dkim" log_selector.
46 6. Receive duration on <= lines, under a new log_selector "receive_time".
48 7. Options "ipv4_only" and "ipv4_prefer" on the dnslookup router and on
49 routing rules in the manualroute router.
51 8. Expansion item ${sha3:<string>} / ${sha3_<N>:<string>} now also supported
52 under OpenSSL version 1.1.1 or later.
54 9. DKIM operations can now use the Ed25519 algorithm in addition to RSA, under
55 GnuTLS 3.6.0 or OpenSSL 1.1.1 or later.
57 10. Builtin feature-macros _CRYPTO_HASH_SHA3 and _CRYPTO_SIGN_ED25519, library
60 11. "exim -bP macro <name>" returns caller-usable status.
62 12. Expansion item ${authresults {<machine>}} for creating an
63 Authentication-Results: header.
65 13. EXPERIMENTAL_ARC. See the experimental.spec file.
66 See also new util/renew-opendmarc-tlds.sh script for use with DMARC/ARC.
68 14: A dane:fail event, intended to facilitate reporting.
70 15. "Lightweight" support for Redis Cluster. Requires redis_servers list to
71 contain all the servers in the cluster, all of which must be reachable from
72 the running exim instance. If the cluster has master/slave replication, the
73 list must contain all the master and slave servers.
75 16. Add an option to the Avast scanner interface: "pass_unscanned". This
76 allows to treat unscanned files as clean. Files may be unscanned for
77 several reasons: decompression bombs, broken archives.
83 1. PKG_CONFIG_PATH can now be set in Local/Makefile;
84 wildcards will be expanded, values are collapsed.
86 2. The ${readsocket } expansion now takes an option to not shutdown the
87 connection after sending the query string. The default remains to do so.
89 3. An smtp transport option "hosts_noproxy_tls" to control whether multiple
90 deliveries on a single TCP connection can maintain a TLS connection
91 open. By default disabled for all hosts, doing so saves the cost of
92 making new TLS sessions, at the cost of having to proxy the data via
93 another process. Logging is also affected.
95 4. A malware connection type for the FPSCAND protocol.
97 5. An option for recipient verify callouts to hold the connection open for
98 further recipients and for delivery.
100 6. The reproducible build $SOURCE_DATE_EPOCH environment variable is now
103 7. Optionally, an alternate format for spool data-files which matches the
104 wire format - meaning more efficient reception and transmission (at the
105 cost of difficulty with standard Unix tools). Only used for messages
106 received using the ESMTP CHUNKING option, and when a new main-section
107 option "spool_wireformat" (false by default) is set.
109 8. New main configuration option "commandline_checks_require_admin" to
110 restrict who can use various introspection options.
112 9. New option modifier "no_check" for quota and quota_filecount
113 appendfile transport.
115 10. Variable $smtp_command_history returning a comma-sep list of recent
118 11. Millisecond timetamps in logs, on log_selector "millisec". Also affects
119 log elements QT, DT and D, and timstamps in debug output.
121 12. TCP Fast Open logging. As a server, logs when the SMTP banner was sent
122 while still in SYN_RECV state; as a client logs when the connection
123 is opened with a TFO cookie.
125 13. DKIM support for multiple signing, by domain and/or key-selector.
126 DKIM support for multiple hashes, and for alternate-identity tags.
127 Builtin macro with default list of signed headers.
128 Better syntax for specifying oversigning.
129 The DKIM ACL can override verification status, and status is visible in
132 14. Exipick understands -C|--config for an alternative Exim
135 15. TCP Fast Open used, with data-on-SYN, for client SMTP via SOCKS5 proxy,
136 for ${readsocket } expansions, and for ClamAV.
138 16. The "-be" expansion test mode now supports macros. Macros are expanded
139 in test lines, and new macros can be defined.
141 17. Support for server-side dual-certificate-stacks (eg. RSA + ECDSA).
147 1. Allow relative config file names for ".include"
149 2. A main-section config option "debug_store" to control the checks on
150 variable locations during store-reset. Normally false but can be enabled
151 when a memory corrution issue is suspected on a production system.
157 1. The new perl_taintmode option allows to run the embedded perl
158 interpreter in taint mode.
160 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
162 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
165 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
166 N can be 224, 256 (default), 384, 512.
167 With GnuTLS 3.5.0 or later, only.
169 5. Facility for named queues: A command-line argument can specify
170 the queue name for a queue operation, and an ACL modifier can set
171 the queue to be used for a message. A $queue_name variable gives
174 6. New expansion operators base32/base32d.
176 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
177 performance increase and network load decrease. Main config option
178 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
181 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
183 9. Expansion operator escape8bit, like escape but not touching newline etc..
185 10. Feature macros, generated from compile options. All start with "_HAVE_"
186 and go on with some roughly recognisable name. Driver macros, for
187 router, transport and authentication drivers; names starting with "_DRIVER_".
188 Option macros, for each configuration-file option; all start with "_OPT_".
189 Use the "-bP macros" command-line option to see what is present.
191 11. Integer values for options can take a "G" multiplier.
193 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
194 returns from the target back to the initiator, rather than spooling the
197 13. New built-in constants available for tls_dhparam and default changed.
199 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
200 out copies of the message spool files for use by 3rd-party scanners.
202 15. A new option on the smtp transport, hosts_try_fastopen. If the system
203 supports it (on Linux it must be enabled in the kernel by the sysadmin)
204 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
205 but it permits a peer that also supports the facility to send its SMTP
206 banner immediately after the SYN,ACK segment rather then waiting for
207 another ACK - so saving up to one roundtrip time. Because it requires
208 previous communication with the peer (we save a cookie from it) this
209 will only become active on frequently-contacted destinations.
211 16. A new syslog_pid option to suppress PID duplication in syslog lines.
217 1. The ACL conditions regex and mime_regex now capture substrings
218 into numeric variables $regex1 to 9, like the "match" expansion condition.
220 2. New $callout_address variable records the address used for a spam=,
221 malware= or verify= callout.
223 3. Transports now take a "max_parallel" option, to limit concurrency.
225 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
226 The latter expands to a 8-element colon-sep set of hex digits including
227 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
228 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
229 The former operator strips leading zeroes and collapses the longest
230 set of 0-groups to a double-colon.
232 5. New "-bP config" support, to dump the effective configuration.
234 6. New $dkim_key_length variable.
236 7. New base64d and base64 expansion items (the existing str2b64 being a
237 synonym of the latter). Add support in base64 for certificates.
239 8. New main configuration option "bounce_return_linesize_limit" to
240 avoid oversize bodies in bounces. The default value matches RFC
243 9. New $initial_cwd expansion variable.
249 1. Support for using the system standard CA bundle.
251 2. New expansion items $config_file, $config_dir, containing the file
252 and directory name of the main configuration file. Also $exim_version.
254 3. New "malware=" support for Avast.
256 4. New "spam=" variant option for Rspamd.
258 5. Assorted options on malware= and spam= scanners.
260 6. A command-line option to write a comment into the logfile.
262 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
263 be configured to make connections via socks5 proxies.
265 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
266 the transmission of UTF-8 envelope addresses.
268 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
269 used encoding of Maildir folder names.
271 10. A logging option for slow DNS lookups.
273 11. New ${env {<variable>}} expansion.
275 12. A non-SMTP authenticator using information from TLS client certificates.
277 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
278 Patch originally by Wolfgang Breyha.
280 14. Main option "dns_trust_aa" for trusting your local nameserver at the
281 same level as DNSSEC.
287 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
288 DANE SMTP draft to assess a secure chain of trust of the certificate
289 used to establish the TLS connection based on a TLSA record in the
290 domain of the sender.
292 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
293 and several new events have been created. The reason is because it has
294 been expanded beyond just firing events during the transport phase. Any
295 existing TPDA transport options will have to be rewritten to use a new
296 $event_name expansion variable in a condition. Refer to the
297 experimental-spec.txt for details and examples.
299 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
300 server certs used for TLS match the result of the MX lookup. It does
301 not use the same mechanism as DANE.
311 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
312 configured to expect an initial header from a proxy that will make the
313 actual external source IP:host be used in exim instead of the IP of the
314 proxy that is connecting to it.
316 2. New verify option header_names_ascii, which will check to make sure
317 there are no non-ASCII characters in header names. Exim itself handles
318 those non-ASCII characters, but downstream apps may not, so Exim can
319 detect and reject if those characters are present.
321 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
322 codepoints with valid ones.
324 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
325 command line and matching a regex against the return data for trigger
326 and a second regex to extract malware_name. The mail spoolfile name can
327 be included in the command line.
329 5. The smtp transport now supports options "tls_verify_hosts" and
330 "tls_try_verify_hosts". If either is set the certificate verification
331 is split from the encryption operation. The default remains that a failed
332 verification cancels the encryption.
334 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
335 lookup can now set a list of servers to use that is different from the
338 7. New command-line option -C for exiqgrep to specify alternate exim.conf
339 file when searching the queue.
341 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
343 9. Support for DNSSEC on outbound connections.
345 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
346 "certextract" to extract fields from them. Hash operators md5 and sha1
347 work over them for generating fingerprints, and a new sha256 operator
350 11. PRDR is now supported dy default.
352 12. OCSP stapling is now supported by default.
354 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
355 Delivery Status Notification messages in MIME format, and negotiate
356 DSN features per RFC 3461.
362 1. New command-line option -bI:sieve will list all supported sieve extensions
363 of this Exim build on standard output, one per line.
364 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
365 query this to establish the correct list to include in the protocol's
366 SIEVE capability line.
368 2. If the -n option is combined with the -bP option, then the name of an
369 emitted option is not output, only the value (if visible to you).
370 For instance, "exim -n -bP pid_file_path" should just emit a pathname
371 followed by a newline, and no other text.
373 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
374 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
375 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
376 acceptable for security. (Option accepted but ignored if using OpenSSL).
377 Defaults to 1024, the old value. May be lowered only to 512, or raised as
378 far as you like. Raising this may hinder TLS interoperability with other
379 sites and is not currently recommended. Lowering this will permit you to
380 establish a TLS session which is not as secure as you might like.
382 Unless you really know what you are doing, leave it alone.
384 4. If not built with DISABLE_DNSSEC, Exim now has the main option
385 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
386 to send the DO flag to your recursive resolver. If you have a recursive
387 resolver, which can set the Authenticated Data (AD) flag in results, Exim
388 can now detect this. Exim does not perform validation itself, instead
389 relying upon a trusted path to the resolver.
391 Current status: work-in-progress; $sender_host_dnssec variable added.
393 5. DSCP support for outbound connections: on a transport using the smtp driver,
394 set "dscp = ef", for instance, to cause the connections to have the relevant
395 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
397 Similarly for inbound connections, there is a new control modifier, dscp,
398 so "warn control = dscp/ef" in the connect ACL, or after authentication.
400 Supported values depend upon system libraries. "exim -bI:dscp" to list the
401 ones Exim knows of. You can also set a raw number 0..0x3F.
403 6. The -G command-line flag is no longer ignored; it is now equivalent to an
404 ACL setting "control = suppress_local_fixups". The -L command-line flag
405 is now accepted and forces use of syslog, with the provided tag as the
406 process name. A few other flags used by Sendmail are now accepted and
409 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
410 ACL modifier; works for single-recipient mails which are received on and
411 deliverable via SMTP. Using the connection made for a recipient verify,
412 if requested before the verify, or a new one made for the purpose while
413 the inbound connection is still active. The bulk of the mail item is copied
414 direct from the inbound socket to the outbound (as well as the spool file).
415 When the source notifies the end of data, the data acceptance by the destination
416 is negotiated before the acceptance is sent to the source. If the destination
417 does not accept the mail item, for example due to content-scanning, the item
418 is not accepted from the source and therefore there is no need to generate
419 a bounce mail. This is of benefit when providing a secondary-MX service.
420 The downside is that delays are under the control of the ultimate destination
423 The Received-by: header on items delivered by cutthrough is generated
424 early in reception rather than at the end; this will affect any timestamp
425 included. The log line showing delivery is recorded before that showing
426 reception; it uses a new ">>" tag instead of "=>".
428 To support the feature, verify-callout connections can now use ESMTP and TLS.
429 The usual smtp transport options are honoured, plus a (new, default everything)
430 hosts_verify_avoid_tls.
432 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
433 for specific access to the information for each connection. The old names
434 are present for now but deprecated.
436 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
438 8. New expansion operators ${listnamed:name} to get the content of a named list
439 and ${listcount:string} to count the items in a list.
441 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
442 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
443 modules. For some situations this is desirable, but we expect admin in
444 those situations to know they want the feature. More commonly, it means
445 that GUI user modules get loaded and are broken by the setuid Exim being
446 unable to access files specified in environment variables and passed
447 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
448 unless this new option is set.
450 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
451 so have also added a build option which can be used to build Exim with GnuTLS
452 but without trying to use any kind of PKCS11 support. Uncomment this in the
455 AVOID_GNUTLS_PKCS11=yes
457 10. The "acl = name" condition on an ACL now supports optional arguments.
458 New expansion item "${acl {name}{arg}...}" and expansion condition
459 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
460 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
461 Variable $acl_narg contains the number of arguments. If the ACL sets
462 a "message =" value this becomes the result of the expansion item,
463 or the value of $value for the expansion condition. If the ACL returns
464 accept the expansion condition is true; if reject, false. A defer
465 return results in a forced fail.
467 11. Routers and transports can now have multiple headers_add and headers_remove
468 option lines. The concatenated list is used.
470 12. New ACL modifier "remove_header" can remove headers before message gets
471 handled by routers/transports.
473 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
474 "aaaa" and "a" lookups is done and the full set of results returned.
476 14. New expansion variable $headers_added with content from ACL add_header
477 modifier (but not yet added to message).
479 15. New 8bitmime status logging option for received messages. Log field "M8S".
481 16. New authenticated_sender logging option, adding to log field "A".
483 17. New expansion variables $router_name and $transport_name. Useful
484 particularly for debug_print as -bt command-line option does not
485 require privilege whereas -d does.
487 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
488 proposed extension to SMTP from Eric Hall.
490 19. The pipe transport has gained the force_command option, to allow
491 decorating commands from user .forward pipe aliases with prefix
492 wrappers, for instance.
494 20. Callout connections can now AUTH; the same controls as normal delivery
497 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
498 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
499 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
500 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
501 dmarc_status. It adds new control flags dmarc_disable_verify and
502 dmarc_enable_forensic. The default for the dmarc_tld_file option is
503 "/etc/exim/opendmarc.tlds" and can be changed via EDITME.
505 22. Add expansion variable $authenticated_fail_id, which is the username
506 provided to the authentication method which failed. It is available
507 for use in subsequent ACL processing (typically quit or notquit ACLs).
509 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
512 24. New ${hexquote:..string..} expansion operator converts non-printable
513 characters in the string to \xNN form.
515 25. Experimental TPDA (Transport Post Delivery Action) function added.
516 Patch provided by Axel Rau.
518 26. Experimental Redis lookup added. Patch provided by Warren Baker.
524 1. New authenticator driver, "gsasl". Server-only (at present).
525 This is a SASL interface, licensed under GPL, which can be found at
526 http://www.gnu.org/software/gsasl/.
527 This system does not provide sources of data for authentication, so
528 careful use needs to be made of the conditions in Exim.
530 2. New authenticator driver, "heimdal_gssapi". Server-only.
531 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
532 is no longer honoured for setuid programs by Heimdal. Use the
533 "server_keytab" option to point to the keytab.
535 3. The "pkg-config" system can now be used when building Exim to reference
536 cflags and library information for lookups and authenticators, rather
537 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
538 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
539 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
541 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
542 find the headers and libraries for PCRE.
544 4. New expansion variable $tls_bits.
546 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
547 be joined together with ASCII NUL characters to construct the key to pass
548 into the DBM library. Can be used with gsasl to access sasldb2 files as
551 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
553 Avoid release 1.0.1a if you can. Note that the default value of
554 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
555 increased susceptibility to attack. This may still have interoperability
556 implications for very old clients (see version 4.31 change 37) but
557 administrators can choose to make the trade-off themselves and restore
558 compatibility at the cost of session security.
560 7. Use of the new expansion variable $tls_sni in the main configuration option
561 tls_certificate will cause Exim to re-expand the option, if the client
562 sends the TLS Server Name Indication extension, to permit choosing a
563 different certificate; tls_privatekey will also be re-expanded. You must
564 still set these options to expand to valid files when $tls_sni is not set.
566 The SMTP Transport has gained the option tls_sni, which will set a hostname
567 for outbound TLS sessions, and set $tls_sni too.
569 A new log_selector, +tls_sni, has been added, to log received SNI values
570 for Exim as a server.
572 8. The existing "accept_8bitmime" option now defaults to true. This means
573 that Exim is deliberately not strictly RFC compliant. We're following
574 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
575 Those who disagree, or know that they are talking to mail servers that,
576 even today, are not 8-bit clean, need to turn off this option.
578 9. Exim can now be started with -bw (with an optional timeout, given as
579 -bw<timespec>). With this, stdin at startup is a socket that is
580 already listening for connections. This has a more modern name of
581 "socket activation", but forcing the activated socket to fd 0. We're
582 interested in adding more support for modern variants.
584 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
585 for numbers indicates multiplication by 1024^3.
587 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
588 gnutls_require_mac & gnutls_require_protocols are no longer supported.
589 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
590 string, documentation for which is at:
591 http://www.gnutls.org/manual/html_node/Priority-Strings.html
593 SNI support has been added to Exim's GnuTLS integration too.
595 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
596 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
598 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
599 is now available. If the contents of the file are valid, then Exim will
600 send that back in response to a TLS status request; this is OCSP Stapling.
601 Exim will not maintain the contents of the file in any way: administrators
602 are responsible for ensuring that it is up-to-date.
604 See "experimental-spec.txt" for more details.
606 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
607 identically to TXT record lookups.
609 14. New expansion variable $tod_epoch_l for higher-precision time.
611 15. New global option tls_dh_max_bits, defaulting to current value of NSS
612 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
613 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
615 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
616 Option can now be a path or an identifier for a standard prime.
617 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
618 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
621 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
622 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
623 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
629 1. New options for the ratelimit ACL condition: /count= and /unique=.
630 The /noupdate option has been replaced by a /readonly option.
632 2. The SMTP transport's protocol option may now be set to "smtps", to
633 use SSL-on-connect outbound.
635 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
636 there is a problem talking to the AV scanner, or the AV scanner running.
638 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
639 and check if the search item is a member of the list. This does not
640 support named lists, but does subject the list part to string expansion.
642 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
643 built, Exim no longer performs string expansion on the second string of
644 the match_* expansion conditions: "match_address", "match_domain",
645 "match_ip" & "match_local_part". Named lists can still be used.
651 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
652 or off in the resolver library.
658 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
659 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
660 libraries. The following global options have been added in support of
661 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
662 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
664 2. The pipe transport now takes a boolean option, "freeze_signal", default
665 false. When true, if the external delivery command exits on a signal then
666 Exim will freeze the message in the queue, instead of generating a bounce.
668 3. Log filenames may now use %M as an escape, instead of %D (still available).
669 The %M pattern expands to yyyymm, providing month-level resolution.
671 4. The $message_linecount variable is now updated for the maildir_tag option,
672 in the same way as $message_size, to reflect the real number of lines,
673 including any header additions or removals from transport.
675 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
676 Exim now selects entries randomly, to better scale in a cluster setup.
682 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
683 the flaw permitted the Exim run-time user to cause root to append to
684 arbitrary files of the attacker's choosing, with the content based
685 on content supplied by the attacker.
687 2. Exim now supports loading some lookup types at run-time, using your
688 platform's dlopen() functionality. This has limited platform support
689 and the intention is not to support every variant, it's limited to
690 dlopen(). This permits the main Exim binary to not be linked against
691 all the libraries needed for all the lookup types.
697 NOTE: this version is not guaranteed backwards-compatible, please read the
698 items below carefully
700 1. A new main configuration option, "openssl_options", is available if Exim
701 is built with SSL support provided by OpenSSL. The option allows
702 administrators to specify OpenSSL options to be used on connections;
703 typically this is to set bug compatibility features which the OpenSSL
704 developers have not enabled by default. There may be security
705 consequences for certain options, so these should not be changed
708 2. A new pipe transport option, "permit_coredumps", may help with problem
709 diagnosis in some scenarios. Note that Exim is typically installed as
710 a setuid binary, which on most OSes will inhibit coredumps by default,
711 so that safety mechanism would have to be overridden for this option to
712 be able to take effect.
714 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
715 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
716 Note that this switches Exim to use a new API ("INSTREAM") and a future
717 release of ClamAV will remove support for the old API ("STREAM").
719 The av_scanner option, when set to "clamd", now takes an optional third
720 part, "local", which causes Exim to pass a filename to ClamAV instead of
721 the file content. This is the same behaviour as when clamd is pointed at
722 a Unix-domain socket. For example:
724 av_scanner = clamd:192.0.2.3 1234:local
726 ClamAV's ExtendedDetectionInfo response format is now handled.
728 4. There is now a -bmalware option, restricted to admin users. This option
729 takes one parameter, a filename, and scans that file with Exim's
730 malware-scanning framework. This is intended purely as a debugging aid
731 to ensure that Exim's scanning is working, not to replace other tools.
732 Note that the ACL framework is not invoked, so if av_scanner references
733 ACL variables without a fallback then this will fail.
735 5. There is a new expansion operator, "reverse_ip", which will reverse IP
736 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
738 ${reverse_ip:192.0.2.4}
740 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
741 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
743 6. There is a new ACL control called "debug", to enable debug logging.
744 This allows selective logging of certain incoming transactions within
745 production environments, with some care. It takes two options, "tag"
746 and "opts"; "tag" is included in the filename of the log and "opts"
747 is used as per the -d<options> command-line option. Examples, which
748 don't all make sense in all contexts:
751 control = debug/tag=.$sender_host_address
752 control = debug/opts=+expand+acl
753 control = debug/tag=.$message_exim_id/opts=+expand
755 7. It has always been implicit in the design and the documentation that
756 "the Exim user" is not root. src/EDITME said that using root was
757 "very strongly discouraged". This is not enough to keep people from
758 shooting themselves in the foot in days when many don't configure Exim
759 themselves but via package build managers. The security consequences of
760 running various bits of network code are severe if there should be bugs in
761 them. As such, the Exim user may no longer be root. If configured
762 statically, Exim will refuse to build. If configured as ref:user then Exim
763 will exit shortly after start-up. If you must shoot yourself in the foot,
764 then henceforth you will have to maintain your own local patches to strip
767 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
768 condition logic to determine truth/failure and will fail to expand many
769 strings, bool_lax{} uses the router condition logic, where most strings
771 Note: bool{00} is false, bool_lax{00} is true.
773 9. Routers now support multiple "condition" tests.
775 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
776 Setting this allows an admin to define which entry in the tcpwrappers
777 config file will be used to control access to the daemon. This option
778 is only available when Exim is built with USE_TCP_WRAPPERS. The
779 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
782 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
783 the Exim run-time user, instead of root.
785 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
786 is forced on. This is mitigated by the new build option
787 TRUSTED_CONFIG_LIST which defines a list of configuration files which
788 are trusted; one per line. If a config file is owned by root and matches
789 a pathname in the list, then it may be invoked by the Exim build-time
790 user without Exim relinquishing root privileges.
792 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
793 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
794 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
795 include the main config. As a transition mechanism, we are temporarily
796 providing a work-around: the new build option WHITELIST_D_MACROS provides
797 a colon-separated list of macro names which may be overridden by the Exim
798 run-time user. The values of these macros are constrained to the regex
799 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
805 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
806 writable, the other to locking of MBX folders (not mbox).
808 2. MySQL stored procedures are now supported.
810 3. The dkim_domain transport option is now a list, not a single string, and
811 messages will be signed for each element in the list (discarding
814 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
815 in the presence of multiple character strings within the RR. Prior to 4.70,
816 only the first string would be returned. The dnsdb lookup now, by default,
817 preserves the pre-4.70 semantics, but also now takes an extended output
818 separator specification. The separator can be followed by a semicolon, to
819 concatenate the individual text strings together with no join character,
820 or by a comma and a second separator character, in which case the text
821 strings within a TXT record are joined on that second character.
822 Administrators are reminded that DNS provides no ordering guarantees
823 between multiple records in an RRset. For example:
825 foo.example. IN TXT "a" "b" "c"
826 foo.example. IN TXT "d" "e" "f"
828 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
829 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
830 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
836 1. Native DKIM support without an external library.
837 (Note that if no action to prevent it is taken, a straight upgrade will
838 result in DKIM verification of all signed incoming emails. See spec
839 for details on conditionally disabling)
841 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
843 3. There is now a bool{} expansion condition which maps certain strings to
844 true/false condition values (most likely of use in conjunction with the
845 and{} expansion operator).
847 4. The $spam_score, $spam_bar and $spam_report variables are now available
850 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
851 options, provided that Exim is invoked by an admin_user.
853 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
854 which increases compatibility with older clients at the cost of decreased
855 security. Don't set this unless you need to support such clients.
857 7. There is a new expansion operator, ${randint:...} which will produce a
858 "random" number less than the supplied integer. This randomness is
859 not guaranteed to be cryptographically strong, but depending upon how
860 Exim was built may be better than the most naive schemes.
862 8. Exim now explicitly ensures that SHA256 is available when linked against
865 9. The transport_filter_timeout option now applies to SMTP transports too.
871 1. Preliminary DKIM support in Experimental.
877 1. The body_linecount and body_zerocount C variables are now exported in the
880 2. When a dnslists lookup succeeds, the key that was looked up is now placed
881 in $dnslist_matched. When the key is an IP address, it is not reversed in
882 this variable (though it is, of course, in the actual lookup). In simple
885 deny dnslists = spamhaus.example
887 the key is also available in another variable (in this case,
888 $sender_host_address). In more complicated cases, however, this is not
889 true. For example, using a data lookup might generate a dnslists lookup
892 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
894 If this condition succeeds, the value in $dnslist_matched might be
895 192.168.6.7 (for example).
897 3. Authenticators now have a client_condition option. When Exim is running as
898 a client, it skips an authenticator whose client_condition expansion yields
899 "0", "no", or "false". This can be used, for example, to skip plain text
900 authenticators when the connection is not encrypted by a setting such as:
902 client_condition = ${if !eq{$tls_cipher}{}}
904 Note that the 4.67 documentation states that $tls_cipher contains the
905 cipher used for incoming messages. In fact, during SMTP delivery, it
906 contains the cipher used for the delivery. The same is true for
909 4. There is now a -Mvc <message-id> option, which outputs a copy of the
910 message to the standard output, in RFC 2822 format. The option can be used
911 only by an admin user.
913 5. There is now a /noupdate option for the ratelimit ACL condition. It
914 computes the rate and checks the limit as normal, but it does not update
915 the saved data. This means that, in relevant ACLs, it is possible to lookup
916 the existence of a specified (or auto-generated) ratelimit key without
917 incrementing the ratelimit counter for that key.
919 In order for this to be useful, another ACL entry must set the rate
920 for the same key somewhere (otherwise it will always be zero).
925 # Read the rate; if it doesn't exist or is below the maximum
927 deny ratelimit = 100 / 5m / strict / noupdate
928 log_message = RATE: $sender_rate / $sender_rate_period \
929 (max $sender_rate_limit)
931 [... some other logic and tests...]
933 warn ratelimit = 100 / 5m / strict / per_cmd
934 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
935 (max $sender_rate_limit)
936 condition = ${if le{$sender_rate}{$sender_rate_limit}}
940 6. The variable $max_received_linelength contains the number of bytes in the
941 longest line that was received as part of the message, not counting the
942 line termination character(s).
944 7. Host lists can now include +ignore_defer and +include_defer, analagous to
945 +ignore_unknown and +include_unknown. These options should be used with
946 care, probably only in non-critical host lists such as whitelists.
948 8. There's a new option called queue_only_load_latch, which defaults true.
949 If set false when queue_only_load is greater than zero, Exim re-evaluates
950 the load for each incoming message in an SMTP session. Otherwise, once one
951 message is queued, the remainder are also.
953 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
954 cases when an SMTP session ends without sending QUIT. However, when Exim
955 itself is is bad trouble, such as being unable to write to its log files,
956 this ACL is not run, because it might try to do things (such as write to
957 log files) that make the situation even worse.
959 Like the QUIT ACL, this new ACL is provided to make it possible to gather
960 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
961 modifier is forbidden in this ACL.
963 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
964 to a string that indicates the reason for the termination of the SMTP
965 connection. The possible values are:
967 acl-drop Another ACL issued a "drop" command
968 bad-commands Too many unknown or non-mail commands
969 command-timeout Timeout while reading SMTP commands
970 connection-lost The SMTP connection has been lost
971 data-timeout Timeout while reading message data
972 local-scan-error The local_scan() function crashed
973 local-scan-timeout The local_scan() function timed out
974 signal-exit SIGTERM or SIGINT
975 synchronization-error SMTP synchronization error
976 tls-failed TLS failed to start
978 In most cases when an SMTP connection is closed without having received
979 QUIT, Exim sends an SMTP response message before actually closing the
980 connection. With the exception of acl-drop, the default message can be
981 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
982 "drop" verb in another ACL, it is the message from the other ACL that is
985 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
986 servers with individual queries. This is done by starting the query with
987 "servers=x:y:z;", where each item in the list may take one of two forms:
989 (1) If it is just a host name, the appropriate global option (mysql_servers
990 or pgsql_servers) is searched for a host of the same name, and the
991 remaining parameters (database, user, password) are taken from there.
993 (2) If it contains any slashes, it is taken as a complete parameter set.
995 The list of servers is used in exactly the same was as the global list.
996 Once a connection to a server has happened and a query has been
997 successfully executed, processing of the lookup ceases.
999 This feature is intended for use in master/slave situations where updates
1000 are occurring, and one wants to update a master rather than a slave. If the
1001 masters are in the list for reading, you might have:
1003 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
1005 In an updating lookup, you could then write
1007 ${lookup mysql{servers=master; UPDATE ...}
1009 If, on the other hand, the master is not to be used for reading lookups:
1011 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
1013 you can still update the master by
1015 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
1017 11. The message_body_newlines option (default FALSE, for backwards
1018 compatibility) can be used to control whether newlines are present in
1019 $message_body and $message_body_end. If it is FALSE, they are replaced by
1026 1. There is a new log selector called smtp_no_mail, which is not included in
1027 the default setting. When it is set, a line is written to the main log
1028 whenever an accepted SMTP connection terminates without having issued a
1031 2. When an item in a dnslists list is followed by = and & and a list of IP
1032 addresses, the behaviour was not clear when the lookup returned more than
1033 one IP address. This has been solved by the addition of == and =& for "all"
1034 rather than the default "any" matching.
1036 3. Up till now, the only control over which cipher suites GnuTLS uses has been
1037 for the cipher algorithms. New options have been added to allow some of the
1038 other parameters to be varied.
1040 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
1041 set, Exim compiles a runtime option called disable_fsync.
1043 5. There is a new variable called $smtp_count_at_connection_start.
1045 6. There's a new control called no_pipelining.
1047 7. There are two new variables called $sending_ip_address and $sending_port.
1048 These are set whenever an SMTP connection to another host has been set up.
1050 8. The expansion of the helo_data option in the smtp transport now happens
1051 after the connection to the server has been made.
1053 9. There is a new expansion operator ${rfc2047d: that decodes strings that
1054 are encoded as per RFC 2047.
1056 10. There is a new log selector called "pid", which causes the current process
1057 id to be added to every log line, in square brackets, immediately after the
1060 11. Exim has been modified so that it flushes SMTP output before implementing
1061 a delay in an ACL. It also flushes the output before performing a callout,
1062 as this can take a substantial time. These behaviours can be disabled by
1063 obeying control = no_delay_flush or control = no_callout_flush,
1064 respectively, at some earlier stage of the connection.
1066 12. There are two new expansion conditions that iterate over a list. They are
1067 called forany and forall.
1069 13. There's a new global option called dsn_from that can be used to vary the
1070 contents of From: lines in bounces and other automatically generated
1071 messages ("delivery status notifications" - hence the name of the option).
1073 14. The smtp transport has a new option called hosts_avoid_pipelining.
1075 15. By default, exigrep does case-insensitive matches. There is now a -I option
1076 that makes it case-sensitive.
1078 16. A number of new features ("addresses", "map", "filter", and "reduce") have
1079 been added to string expansions to make it easier to process lists of
1080 items, typically addresses.
1082 17. There's a new ACL modifier called "continue". It does nothing of itself,
1083 and processing of the ACL always continues with the next condition or
1084 modifier. It is provided so that the side effects of expanding its argument
1087 18. It is now possible to use newline and other control characters (those with
1088 values less than 32, plus DEL) as separators in lists.
1090 19. The exigrep utility now has a -v option, which inverts the matching
1093 20. The host_find_failed option in the manualroute router can now be set to
1100 No new features were added to 4.66.
1106 No new features were added to 4.65.
1112 1. ACL variables can now be given arbitrary names, as long as they start with
1113 "acl_c" or "acl_m" (for connection variables and message variables), are at
1114 least six characters long, with the sixth character being either a digit or
1117 2. There is a new ACL modifier called log_reject_target. It makes it possible
1118 to specify which logs are used for messages about ACL rejections.
1120 3. There is a new authenticator called "dovecot". This is an interface to the
1121 authentication facility of the Dovecot POP/IMAP server, which can support a
1122 number of authentication methods.
1124 4. The variable $message_headers_raw provides a concatenation of all the
1125 messages's headers without any decoding. This is in contrast to
1126 $message_headers, which does RFC2047 decoding on the header contents.
1128 5. In a DNS black list, if two domain names, comma-separated, are given, the
1129 second is used first to do an initial check, making use of any IP value
1130 restrictions that are set. If there is a match, the first domain is used,
1131 without any IP value restrictions, to get the TXT record.
1133 6. All authenticators now have a server_condition option.
1135 7. There is a new command-line option called -Mset. It is useful only in
1136 conjunction with -be (that is, when testing string expansions). It must be
1137 followed by a message id; Exim loads the given message from its spool
1138 before doing the expansions.
1140 8. Another similar new command-line option is called -bem. It operates like
1141 -be except that it must be followed by the name of a file that contains a
1144 9. When an address is delayed because of a 4xx response to a RCPT command, it
1145 is now the combination of sender and recipient that is delayed in
1146 subsequent queue runs until its retry time is reached.
1148 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1149 shift, have been added to the eval: and eval10: expansion items.
1151 11. The variables $interface_address and $interface_port have been renamed
1152 as $received_ip_address and $received_port, to make it clear that they
1153 relate to message reception rather than delivery. (The old names remain
1154 available for compatibility.)
1156 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1157 to vary the message that is sent when an SMTP command is accepted.
1163 1. There is a new Boolean option called filter_prepend_home for the redirect
1166 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1167 start of receiving a non-SMTP message, before any of the message has been
1170 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1171 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1172 start of the message for an SMTP error code.
1174 4. There is a new parameter for LDAP lookups called "referrals", which takes
1175 one of the settings "follow" (the default) or "nofollow".
1177 5. Version 20070721.2 of exipick now included, offering these new options:
1179 After all other sorting options have bee processed, reverse order
1180 before displaying messages (-R is synonym).
1182 Randomize order of matching messages before displaying.
1184 Instead of displaying the matching messages, display the sum
1186 --sort <variable>[,<variable>...]
1187 Before displaying matching messages, sort the messages according to
1188 each messages value for each variable.
1190 Negate the value for every test (returns inverse output from the
1191 same criteria without --not).
1197 1. The ${readsocket expansion item now supports Internet domain sockets as well
1198 as Unix domain sockets. If the first argument begins "inet:", it must be of
1199 the form "inet:host:port". The port is mandatory; it may be a number or the
1200 name of a TCP port in /etc/services. The host may be a name, or it may be an
1201 IP address. An ip address may optionally be enclosed in square brackets.
1202 This is best for IPv6 addresses. For example:
1204 ${readsocket{inet:[::1]:1234}{<request data>}...
1206 Only a single host name may be given, but if looking it up yield more than
1207 one IP address, they are each tried in turn until a connection is made. Once
1208 a connection has been made, the behaviour is as for ${readsocket with a Unix
1211 2. If a redirect router sets up file or pipe deliveries for more than one
1212 incoming address, and the relevant transport has batch_max set greater than
1213 one, a batch delivery now occurs.
1215 3. The appendfile transport has a new option called maildirfolder_create_regex.
1216 Its value is a regular expression. For a maildir delivery, this is matched
1217 against the maildir directory; if it matches, Exim ensures that a
1218 maildirfolder file is created alongside the new, cur, and tmp directories.
1224 The documentation is up-to-date for the 4.61 release. Major new features since
1225 the 4.60 release are:
1227 . An option called disable_ipv6, to disable the use of IPv6 completely.
1229 . An increase in the number of ACL variables to 20 of each type.
1231 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1232 $2, $3, (though those are still set) because the numeric variables get used
1233 for other things in complicated expansions.
1235 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1237 . It is possible to use setclassresources() on some BSD OS to control the
1238 resources used in pipe deliveries.
1240 . A new ACL modifier called add_header, which can be used with any verb.
1242 . More errors are detectable in retry rules.
1244 There are a number of other additions too.
1250 The documentation is up-to-date for the 4.60 release. Major new features since
1251 the 4.50 release are:
1253 . Support for SQLite.
1255 . Support for IGNOREQUOTA in LMTP.
1257 . Extensions to the "submission mode" features.
1259 . Support for Client SMTP Authorization (CSA).
1261 . Support for ratelimiting hosts and users.
1263 . New expansion items to help with the BATV "prvs" scheme.
1265 . A "match_ip" condition, that matches an IP address against a list.
1267 There are many more minor changes.
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