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. PKG_CONFIG_PATH can now be set in Local/Makefile;
13 wildcards will be expanded, values are collapsed.
15 2. The ${readsocket } expansion now takes an option to not shutdown the
16 connection after sending the query string. The default remains to do so.
18 3. An smtp transport option "hosts_noproxy_tls" to control whether multiple
19 deliveries on a single TCP connection can maintain a TLS connection
20 open. By default disabled for all hosts, doing so saves the cost of
21 making new TLS sessions, at the cost of having to proxy the data via
22 another process. Logging is also affected.
24 4. A malware connection type for the FPSCAND protocol.
26 5. An option for recipient verify callouts to hold the connection open for
27 further recipients and for delivery.
29 6. The reproducible build $SOURCE_DATE_EPOCH environment variable is now
32 7. Optionally, an alternate format for spool data-files which matches the
33 wire format - meaning more efficient reception and transmission (at the
34 cost of difficulty with standard Unix tools). Only used for messages
35 received using the ESMTP CHUNKING option, and when a new main-section
36 option "spool_wireformat" (false by default) is set.
38 8. New main configuration option "commandline_checks_require_admin" to
39 restrict who can use various introspection options.
41 9. New option modifier "no_check" for quota and quota_filecount
44 10. Variable $smtp_command_history returning a comma-sep list of recent
47 11. Millisecond timetamps in logs, on log_selector "millisec".
53 1. Allow relative config file names for ".include"
55 2. A main-section config option "debug_store" to control the checks on
56 variable locations during store-reset. Normally false but can be enabled
57 when a memory corrution issue is suspected on a production system.
63 1. The new perl_taintmode option allows to run the embedded perl
64 interpreter in taint mode.
66 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
68 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
71 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
72 N can be 224, 256 (default), 384, 512.
73 With GnuTLS 3.5.0 or later, only.
75 5. Facility for named queues: A command-line argument can specify
76 the queue name for a queue operation, and an ACL modifier can set
77 the queue to be used for a message. A $queue_name variable gives
80 6. New expansion operators base32/base32d.
82 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
83 performance increase and network load decrease. Main config option
84 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
87 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
89 9. Expansion operator escape8bit, like escape but not touching newline etc..
91 10. Feature macros, generated from compile options. All start with "_HAVE_"
92 and go on with some roughly recognisable name. Driver macros, for
93 router, transport and authentication drivers; names starting with "_DRIVER_".
94 Option macros, for each configuration-file option; all start with "_OPT_".
95 Use the "-bP macros" command-line option to see what is present.
97 11. Integer values for options can take a "G" multiplier.
99 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
100 returns from the target back to the initiator, rather than spooling the
103 13. New built-in constants available for tls_dhparam and default changed.
105 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
106 out copies of the message spool files for use by 3rd-party scanners.
108 15. A new option on the smtp transport, hosts_try_fastopen. If the system
109 supports it (on Linux it must be enabled in the kernel by the sysadmin)
110 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
111 but it permits a peer that also supports the facility to send its SMTP
112 banner immediately after the SYN,ACK segment rather then waiting for
113 another ACK - so saving up to one roundtrip time. Because it requires
114 previous communication with the peer (we save a cookie from it) this
115 will only become active on frequently-contacted destinations.
117 16. A new syslog_pid option to suppress PID duplication in syslog lines.
123 1. The ACL conditions regex and mime_regex now capture substrings
124 into numeric variables $regex1 to 9, like the "match" expansion condition.
126 2. New $callout_address variable records the address used for a spam=,
127 malware= or verify= callout.
129 3. Transports now take a "max_parallel" option, to limit concurrency.
131 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
132 The latter expands to a 8-element colon-sep set of hex digits including
133 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
134 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
135 The former operator strips leading zeroes and collapses the longest
136 set of 0-groups to a double-colon.
138 5. New "-bP config" support, to dump the effective configuration.
140 6. New $dkim_key_length variable.
142 7. New base64d and base64 expansion items (the existing str2b64 being a
143 synonym of the latter). Add support in base64 for certificates.
145 8. New main configuration option "bounce_return_linesize_limit" to
146 avoid oversize bodies in bounces. The default value matches RFC
149 9. New $initial_cwd expansion variable.
155 1. Support for using the system standard CA bundle.
157 2. New expansion items $config_file, $config_dir, containing the file
158 and directory name of the main configuration file. Also $exim_version.
160 3. New "malware=" support for Avast.
162 4. New "spam=" variant option for Rspamd.
164 5. Assorted options on malware= and spam= scanners.
166 6. A command-line option to write a comment into the logfile.
168 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
169 be configured to make connections via socks5 proxies.
171 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
172 the transmission of UTF-8 envelope addresses.
174 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
175 used encoding of Maildir folder names.
177 10. A logging option for slow DNS lookups.
179 11. New ${env {<variable>}} expansion.
181 12. A non-SMTP authenticator using information from TLS client certificates.
183 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
184 Patch originally by Wolfgang Breyha.
186 14. Main option "dns_trust_aa" for trusting your local nameserver at the
187 same level as DNSSEC.
193 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
194 DANE SMTP draft to assess a secure chain of trust of the certificate
195 used to establish the TLS connection based on a TLSA record in the
196 domain of the sender.
198 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
199 and several new events have been created. The reason is because it has
200 been expanded beyond just firing events during the transport phase. Any
201 existing TPDA transport options will have to be rewritten to use a new
202 $event_name expansion variable in a condition. Refer to the
203 experimental-spec.txt for details and examples.
205 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
206 server certs used for TLS match the result of the MX lookup. It does
207 not use the same mechanism as DANE.
217 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
218 configured to expect an initial header from a proxy that will make the
219 actual external source IP:host be used in exim instead of the IP of the
220 proxy that is connecting to it.
222 2. New verify option header_names_ascii, which will check to make sure
223 there are no non-ASCII characters in header names. Exim itself handles
224 those non-ASCII characters, but downstream apps may not, so Exim can
225 detect and reject if those characters are present.
227 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
228 codepoints with valid ones.
230 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
231 command line and matching a regex against the return data for trigger
232 and a second regex to extract malware_name. The mail spoolfile name can
233 be included in the command line.
235 5. The smtp transport now supports options "tls_verify_hosts" and
236 "tls_try_verify_hosts". If either is set the certificate verification
237 is split from the encryption operation. The default remains that a failed
238 verification cancels the encryption.
240 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
241 lookup can now set a list of servers to use that is different from the
244 7. New command-line option -C for exiqgrep to specify alternate exim.conf
245 file when searching the queue.
247 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
249 9. Support for DNSSEC on outbound connections.
251 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
252 "certextract" to extract fields from them. Hash operators md5 and sha1
253 work over them for generating fingerprints, and a new sha256 operator
256 11. PRDR is now supported dy default.
258 12. OCSP stapling is now supported by default.
260 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
261 Delivery Status Notification messages in MIME format, and negotiate
262 DSN features per RFC 3461.
268 1. New command-line option -bI:sieve will list all supported sieve extensions
269 of this Exim build on standard output, one per line.
270 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
271 query this to establish the correct list to include in the protocol's
272 SIEVE capability line.
274 2. If the -n option is combined with the -bP option, then the name of an
275 emitted option is not output, only the value (if visible to you).
276 For instance, "exim -n -bP pid_file_path" should just emit a pathname
277 followed by a newline, and no other text.
279 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
280 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
281 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
282 acceptable for security. (Option accepted but ignored if using OpenSSL).
283 Defaults to 1024, the old value. May be lowered only to 512, or raised as
284 far as you like. Raising this may hinder TLS interoperability with other
285 sites and is not currently recommended. Lowering this will permit you to
286 establish a TLS session which is not as secure as you might like.
288 Unless you really know what you are doing, leave it alone.
290 4. If not built with DISABLE_DNSSEC, Exim now has the main option
291 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
292 to send the DO flag to your recursive resolver. If you have a recursive
293 resolver, which can set the Authenticated Data (AD) flag in results, Exim
294 can now detect this. Exim does not perform validation itself, instead
295 relying upon a trusted path to the resolver.
297 Current status: work-in-progress; $sender_host_dnssec variable added.
299 5. DSCP support for outbound connections: on a transport using the smtp driver,
300 set "dscp = ef", for instance, to cause the connections to have the relevant
301 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
303 Similarly for inbound connections, there is a new control modifier, dscp,
304 so "warn control = dscp/ef" in the connect ACL, or after authentication.
306 Supported values depend upon system libraries. "exim -bI:dscp" to list the
307 ones Exim knows of. You can also set a raw number 0..0x3F.
309 6. The -G command-line flag is no longer ignored; it is now equivalent to an
310 ACL setting "control = suppress_local_fixups". The -L command-line flag
311 is now accepted and forces use of syslog, with the provided tag as the
312 process name. A few other flags used by Sendmail are now accepted and
315 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
316 ACL modifier; works for single-recipient mails which are received on and
317 deliverable via SMTP. Using the connection made for a recipient verify,
318 if requested before the verify, or a new one made for the purpose while
319 the inbound connection is still active. The bulk of the mail item is copied
320 direct from the inbound socket to the outbound (as well as the spool file).
321 When the source notifies the end of data, the data acceptance by the destination
322 is negotiated before the acceptance is sent to the source. If the destination
323 does not accept the mail item, for example due to content-scanning, the item
324 is not accepted from the source and therefore there is no need to generate
325 a bounce mail. This is of benefit when providing a secondary-MX service.
326 The downside is that delays are under the control of the ultimate destination
329 The Received-by: header on items delivered by cutthrough is generated
330 early in reception rather than at the end; this will affect any timestamp
331 included. The log line showing delivery is recorded before that showing
332 reception; it uses a new ">>" tag instead of "=>".
334 To support the feature, verify-callout connections can now use ESMTP and TLS.
335 The usual smtp transport options are honoured, plus a (new, default everything)
336 hosts_verify_avoid_tls.
338 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
339 for specific access to the information for each connection. The old names
340 are present for now but deprecated.
342 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
344 8. New expansion operators ${listnamed:name} to get the content of a named list
345 and ${listcount:string} to count the items in a list.
347 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
348 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
349 modules. For some situations this is desirable, but we expect admin in
350 those situations to know they want the feature. More commonly, it means
351 that GUI user modules get loaded and are broken by the setuid Exim being
352 unable to access files specified in environment variables and passed
353 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
354 unless this new option is set.
356 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
357 so have also added a build option which can be used to build Exim with GnuTLS
358 but without trying to use any kind of PKCS11 support. Uncomment this in the
361 AVOID_GNUTLS_PKCS11=yes
363 10. The "acl = name" condition on an ACL now supports optional arguments.
364 New expansion item "${acl {name}{arg}...}" and expansion condition
365 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
366 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
367 Variable $acl_narg contains the number of arguments. If the ACL sets
368 a "message =" value this becomes the result of the expansion item,
369 or the value of $value for the expansion condition. If the ACL returns
370 accept the expansion condition is true; if reject, false. A defer
371 return results in a forced fail.
373 11. Routers and transports can now have multiple headers_add and headers_remove
374 option lines. The concatenated list is used.
376 12. New ACL modifier "remove_header" can remove headers before message gets
377 handled by routers/transports.
379 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
380 "aaaa" and "a" lookups is done and the full set of results returned.
382 14. New expansion variable $headers_added with content from ACL add_header
383 modifier (but not yet added to message).
385 15. New 8bitmime status logging option for received messages. Log field "M8S".
387 16. New authenticated_sender logging option, adding to log field "A".
389 17. New expansion variables $router_name and $transport_name. Useful
390 particularly for debug_print as -bt command-line option does not
391 require privilege whereas -d does.
393 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
394 proposed extension to SMTP from Eric Hall.
396 19. The pipe transport has gained the force_command option, to allow
397 decorating commands from user .forward pipe aliases with prefix
398 wrappers, for instance.
400 20. Callout connections can now AUTH; the same controls as normal delivery
403 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
404 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
405 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
406 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
407 dmarc_status. It adds new control flags dmarc_disable_verify and
408 dmarc_enable_forensic. The default for the dmarc_tld_file option is
409 "/etc/exim/opendmarc.tlds" and can be changed via EDITME.
411 22. Add expansion variable $authenticated_fail_id, which is the username
412 provided to the authentication method which failed. It is available
413 for use in subsequent ACL processing (typically quit or notquit ACLs).
415 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
418 24. New ${hexquote:..string..} expansion operator converts non-printable
419 characters in the string to \xNN form.
421 25. Experimental TPDA (Transport Post Delivery Action) function added.
422 Patch provided by Axel Rau.
424 26. Experimental Redis lookup added. Patch provided by Warren Baker.
430 1. New authenticator driver, "gsasl". Server-only (at present).
431 This is a SASL interface, licensed under GPL, which can be found at
432 http://www.gnu.org/software/gsasl/.
433 This system does not provide sources of data for authentication, so
434 careful use needs to be made of the conditions in Exim.
436 2. New authenticator driver, "heimdal_gssapi". Server-only.
437 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
438 is no longer honoured for setuid programs by Heimdal. Use the
439 "server_keytab" option to point to the keytab.
441 3. The "pkg-config" system can now be used when building Exim to reference
442 cflags and library information for lookups and authenticators, rather
443 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
444 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
445 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
447 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
448 find the headers and libraries for PCRE.
450 4. New expansion variable $tls_bits.
452 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
453 be joined together with ASCII NUL characters to construct the key to pass
454 into the DBM library. Can be used with gsasl to access sasldb2 files as
457 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
459 Avoid release 1.0.1a if you can. Note that the default value of
460 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
461 increased susceptibility to attack. This may still have interoperability
462 implications for very old clients (see version 4.31 change 37) but
463 administrators can choose to make the trade-off themselves and restore
464 compatibility at the cost of session security.
466 7. Use of the new expansion variable $tls_sni in the main configuration option
467 tls_certificate will cause Exim to re-expand the option, if the client
468 sends the TLS Server Name Indication extension, to permit choosing a
469 different certificate; tls_privatekey will also be re-expanded. You must
470 still set these options to expand to valid files when $tls_sni is not set.
472 The SMTP Transport has gained the option tls_sni, which will set a hostname
473 for outbound TLS sessions, and set $tls_sni too.
475 A new log_selector, +tls_sni, has been added, to log received SNI values
476 for Exim as a server.
478 8. The existing "accept_8bitmime" option now defaults to true. This means
479 that Exim is deliberately not strictly RFC compliant. We're following
480 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
481 Those who disagree, or know that they are talking to mail servers that,
482 even today, are not 8-bit clean, need to turn off this option.
484 9. Exim can now be started with -bw (with an optional timeout, given as
485 -bw<timespec>). With this, stdin at startup is a socket that is
486 already listening for connections. This has a more modern name of
487 "socket activation", but forcing the activated socket to fd 0. We're
488 interested in adding more support for modern variants.
490 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
491 for numbers indicates multiplication by 1024^3.
493 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
494 gnutls_require_mac & gnutls_require_protocols are no longer supported.
495 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
496 string, documentation for which is at:
497 http://www.gnutls.org/manual/html_node/Priority-Strings.html
499 SNI support has been added to Exim's GnuTLS integration too.
501 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
502 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
504 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
505 is now available. If the contents of the file are valid, then Exim will
506 send that back in response to a TLS status request; this is OCSP Stapling.
507 Exim will not maintain the contents of the file in any way: administrators
508 are responsible for ensuring that it is up-to-date.
510 See "experimental-spec.txt" for more details.
512 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
513 identically to TXT record lookups.
515 14. New expansion variable $tod_epoch_l for higher-precision time.
517 15. New global option tls_dh_max_bits, defaulting to current value of NSS
518 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
519 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
521 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
522 Option can now be a path or an identifier for a standard prime.
523 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
524 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
527 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
528 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
529 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
535 1. New options for the ratelimit ACL condition: /count= and /unique=.
536 The /noupdate option has been replaced by a /readonly option.
538 2. The SMTP transport's protocol option may now be set to "smtps", to
539 use SSL-on-connect outbound.
541 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
542 there is a problem talking to the AV scanner, or the AV scanner running.
544 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
545 and check if the search item is a member of the list. This does not
546 support named lists, but does subject the list part to string expansion.
548 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
549 built, Exim no longer performs string expansion on the second string of
550 the match_* expansion conditions: "match_address", "match_domain",
551 "match_ip" & "match_local_part". Named lists can still be used.
557 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
558 or off in the resolver library.
564 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
565 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
566 libraries. The following global options have been added in support of
567 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
568 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
570 2. The pipe transport now takes a boolean option, "freeze_signal", default
571 false. When true, if the external delivery command exits on a signal then
572 Exim will freeze the message in the queue, instead of generating a bounce.
574 3. Log filenames may now use %M as an escape, instead of %D (still available).
575 The %M pattern expands to yyyymm, providing month-level resolution.
577 4. The $message_linecount variable is now updated for the maildir_tag option,
578 in the same way as $message_size, to reflect the real number of lines,
579 including any header additions or removals from transport.
581 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
582 Exim now selects entries randomly, to better scale in a cluster setup.
588 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
589 the flaw permitted the Exim run-time user to cause root to append to
590 arbitrary files of the attacker's choosing, with the content based
591 on content supplied by the attacker.
593 2. Exim now supports loading some lookup types at run-time, using your
594 platform's dlopen() functionality. This has limited platform support
595 and the intention is not to support every variant, it's limited to
596 dlopen(). This permits the main Exim binary to not be linked against
597 all the libraries needed for all the lookup types.
603 NOTE: this version is not guaranteed backwards-compatible, please read the
604 items below carefully
606 1. A new main configuration option, "openssl_options", is available if Exim
607 is built with SSL support provided by OpenSSL. The option allows
608 administrators to specify OpenSSL options to be used on connections;
609 typically this is to set bug compatibility features which the OpenSSL
610 developers have not enabled by default. There may be security
611 consequences for certain options, so these should not be changed
614 2. A new pipe transport option, "permit_coredumps", may help with problem
615 diagnosis in some scenarios. Note that Exim is typically installed as
616 a setuid binary, which on most OSes will inhibit coredumps by default,
617 so that safety mechanism would have to be overridden for this option to
618 be able to take effect.
620 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
621 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
622 Note that this switches Exim to use a new API ("INSTREAM") and a future
623 release of ClamAV will remove support for the old API ("STREAM").
625 The av_scanner option, when set to "clamd", now takes an optional third
626 part, "local", which causes Exim to pass a filename to ClamAV instead of
627 the file content. This is the same behaviour as when clamd is pointed at
628 a Unix-domain socket. For example:
630 av_scanner = clamd:192.0.2.3 1234:local
632 ClamAV's ExtendedDetectionInfo response format is now handled.
634 4. There is now a -bmalware option, restricted to admin users. This option
635 takes one parameter, a filename, and scans that file with Exim's
636 malware-scanning framework. This is intended purely as a debugging aid
637 to ensure that Exim's scanning is working, not to replace other tools.
638 Note that the ACL framework is not invoked, so if av_scanner references
639 ACL variables without a fallback then this will fail.
641 5. There is a new expansion operator, "reverse_ip", which will reverse IP
642 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
644 ${reverse_ip:192.0.2.4}
646 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
647 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
649 6. There is a new ACL control called "debug", to enable debug logging.
650 This allows selective logging of certain incoming transactions within
651 production environments, with some care. It takes two options, "tag"
652 and "opts"; "tag" is included in the filename of the log and "opts"
653 is used as per the -d<options> command-line option. Examples, which
654 don't all make sense in all contexts:
657 control = debug/tag=.$sender_host_address
658 control = debug/opts=+expand+acl
659 control = debug/tag=.$message_exim_id/opts=+expand
661 7. It has always been implicit in the design and the documentation that
662 "the Exim user" is not root. src/EDITME said that using root was
663 "very strongly discouraged". This is not enough to keep people from
664 shooting themselves in the foot in days when many don't configure Exim
665 themselves but via package build managers. The security consequences of
666 running various bits of network code are severe if there should be bugs in
667 them. As such, the Exim user may no longer be root. If configured
668 statically, Exim will refuse to build. If configured as ref:user then Exim
669 will exit shortly after start-up. If you must shoot yourself in the foot,
670 then henceforth you will have to maintain your own local patches to strip
673 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
674 condition logic to determine truth/failure and will fail to expand many
675 strings, bool_lax{} uses the router condition logic, where most strings
677 Note: bool{00} is false, bool_lax{00} is true.
679 9. Routers now support multiple "condition" tests.
681 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
682 Setting this allows an admin to define which entry in the tcpwrappers
683 config file will be used to control access to the daemon. This option
684 is only available when Exim is built with USE_TCP_WRAPPERS. The
685 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
688 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
689 the Exim run-time user, instead of root.
691 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
692 is forced on. This is mitigated by the new build option
693 TRUSTED_CONFIG_LIST which defines a list of configuration files which
694 are trusted; one per line. If a config file is owned by root and matches
695 a pathname in the list, then it may be invoked by the Exim build-time
696 user without Exim relinquishing root privileges.
698 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
699 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
700 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
701 include the main config. As a transition mechanism, we are temporarily
702 providing a work-around: the new build option WHITELIST_D_MACROS provides
703 a colon-separated list of macro names which may be overridden by the Exim
704 run-time user. The values of these macros are constrained to the regex
705 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
711 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
712 writable, the other to locking of MBX folders (not mbox).
714 2. MySQL stored procedures are now supported.
716 3. The dkim_domain transport option is now a list, not a single string, and
717 messages will be signed for each element in the list (discarding
720 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
721 in the presence of multiple character strings within the RR. Prior to 4.70,
722 only the first string would be returned. The dnsdb lookup now, by default,
723 preserves the pre-4.70 semantics, but also now takes an extended output
724 separator specification. The separator can be followed by a semicolon, to
725 concatenate the individual text strings together with no join character,
726 or by a comma and a second separator character, in which case the text
727 strings within a TXT record are joined on that second character.
728 Administrators are reminded that DNS provides no ordering guarantees
729 between multiple records in an RRset. For example:
731 foo.example. IN TXT "a" "b" "c"
732 foo.example. IN TXT "d" "e" "f"
734 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
735 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
736 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
742 1. Native DKIM support without an external library.
743 (Note that if no action to prevent it is taken, a straight upgrade will
744 result in DKIM verification of all signed incoming emails. See spec
745 for details on conditionally disabling)
747 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
749 3. There is now a bool{} expansion condition which maps certain strings to
750 true/false condition values (most likely of use in conjunction with the
751 and{} expansion operator).
753 4. The $spam_score, $spam_bar and $spam_report variables are now available
756 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
757 options, provided that Exim is invoked by an admin_user.
759 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
760 which increases compatibility with older clients at the cost of decreased
761 security. Don't set this unless you need to support such clients.
763 7. There is a new expansion operator, ${randint:...} which will produce a
764 "random" number less than the supplied integer. This randomness is
765 not guaranteed to be cryptographically strong, but depending upon how
766 Exim was built may be better than the most naive schemes.
768 8. Exim now explicitly ensures that SHA256 is available when linked against
771 9. The transport_filter_timeout option now applies to SMTP transports too.
777 1. Preliminary DKIM support in Experimental.
783 1. The body_linecount and body_zerocount C variables are now exported in the
786 2. When a dnslists lookup succeeds, the key that was looked up is now placed
787 in $dnslist_matched. When the key is an IP address, it is not reversed in
788 this variable (though it is, of course, in the actual lookup). In simple
791 deny dnslists = spamhaus.example
793 the key is also available in another variable (in this case,
794 $sender_host_address). In more complicated cases, however, this is not
795 true. For example, using a data lookup might generate a dnslists lookup
798 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
800 If this condition succeeds, the value in $dnslist_matched might be
801 192.168.6.7 (for example).
803 3. Authenticators now have a client_condition option. When Exim is running as
804 a client, it skips an authenticator whose client_condition expansion yields
805 "0", "no", or "false". This can be used, for example, to skip plain text
806 authenticators when the connection is not encrypted by a setting such as:
808 client_condition = ${if !eq{$tls_cipher}{}}
810 Note that the 4.67 documentation states that $tls_cipher contains the
811 cipher used for incoming messages. In fact, during SMTP delivery, it
812 contains the cipher used for the delivery. The same is true for
815 4. There is now a -Mvc <message-id> option, which outputs a copy of the
816 message to the standard output, in RFC 2822 format. The option can be used
817 only by an admin user.
819 5. There is now a /noupdate option for the ratelimit ACL condition. It
820 computes the rate and checks the limit as normal, but it does not update
821 the saved data. This means that, in relevant ACLs, it is possible to lookup
822 the existence of a specified (or auto-generated) ratelimit key without
823 incrementing the ratelimit counter for that key.
825 In order for this to be useful, another ACL entry must set the rate
826 for the same key somewhere (otherwise it will always be zero).
831 # Read the rate; if it doesn't exist or is below the maximum
833 deny ratelimit = 100 / 5m / strict / noupdate
834 log_message = RATE: $sender_rate / $sender_rate_period \
835 (max $sender_rate_limit)
837 [... some other logic and tests...]
839 warn ratelimit = 100 / 5m / strict / per_cmd
840 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
841 (max $sender_rate_limit)
842 condition = ${if le{$sender_rate}{$sender_rate_limit}}
846 6. The variable $max_received_linelength contains the number of bytes in the
847 longest line that was received as part of the message, not counting the
848 line termination character(s).
850 7. Host lists can now include +ignore_defer and +include_defer, analagous to
851 +ignore_unknown and +include_unknown. These options should be used with
852 care, probably only in non-critical host lists such as whitelists.
854 8. There's a new option called queue_only_load_latch, which defaults true.
855 If set false when queue_only_load is greater than zero, Exim re-evaluates
856 the load for each incoming message in an SMTP session. Otherwise, once one
857 message is queued, the remainder are also.
859 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
860 cases when an SMTP session ends without sending QUIT. However, when Exim
861 itself is is bad trouble, such as being unable to write to its log files,
862 this ACL is not run, because it might try to do things (such as write to
863 log files) that make the situation even worse.
865 Like the QUIT ACL, this new ACL is provided to make it possible to gather
866 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
867 modifier is forbidden in this ACL.
869 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
870 to a string that indicates the reason for the termination of the SMTP
871 connection. The possible values are:
873 acl-drop Another ACL issued a "drop" command
874 bad-commands Too many unknown or non-mail commands
875 command-timeout Timeout while reading SMTP commands
876 connection-lost The SMTP connection has been lost
877 data-timeout Timeout while reading message data
878 local-scan-error The local_scan() function crashed
879 local-scan-timeout The local_scan() function timed out
880 signal-exit SIGTERM or SIGINT
881 synchronization-error SMTP synchronization error
882 tls-failed TLS failed to start
884 In most cases when an SMTP connection is closed without having received
885 QUIT, Exim sends an SMTP response message before actually closing the
886 connection. With the exception of acl-drop, the default message can be
887 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
888 "drop" verb in another ACL, it is the message from the other ACL that is
891 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
892 servers with individual queries. This is done by starting the query with
893 "servers=x:y:z;", where each item in the list may take one of two forms:
895 (1) If it is just a host name, the appropriate global option (mysql_servers
896 or pgsql_servers) is searched for a host of the same name, and the
897 remaining parameters (database, user, password) are taken from there.
899 (2) If it contains any slashes, it is taken as a complete parameter set.
901 The list of servers is used in exactly the same was as the global list.
902 Once a connection to a server has happened and a query has been
903 successfully executed, processing of the lookup ceases.
905 This feature is intended for use in master/slave situations where updates
906 are occurring, and one wants to update a master rather than a slave. If the
907 masters are in the list for reading, you might have:
909 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
911 In an updating lookup, you could then write
913 ${lookup mysql{servers=master; UPDATE ...}
915 If, on the other hand, the master is not to be used for reading lookups:
917 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
919 you can still update the master by
921 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
923 11. The message_body_newlines option (default FALSE, for backwards
924 compatibility) can be used to control whether newlines are present in
925 $message_body and $message_body_end. If it is FALSE, they are replaced by
932 1. There is a new log selector called smtp_no_mail, which is not included in
933 the default setting. When it is set, a line is written to the main log
934 whenever an accepted SMTP connection terminates without having issued a
937 2. When an item in a dnslists list is followed by = and & and a list of IP
938 addresses, the behaviour was not clear when the lookup returned more than
939 one IP address. This has been solved by the addition of == and =& for "all"
940 rather than the default "any" matching.
942 3. Up till now, the only control over which cipher suites GnuTLS uses has been
943 for the cipher algorithms. New options have been added to allow some of the
944 other parameters to be varied.
946 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
947 set, Exim compiles a runtime option called disable_fsync.
949 5. There is a new variable called $smtp_count_at_connection_start.
951 6. There's a new control called no_pipelining.
953 7. There are two new variables called $sending_ip_address and $sending_port.
954 These are set whenever an SMTP connection to another host has been set up.
956 8. The expansion of the helo_data option in the smtp transport now happens
957 after the connection to the server has been made.
959 9. There is a new expansion operator ${rfc2047d: that decodes strings that
960 are encoded as per RFC 2047.
962 10. There is a new log selector called "pid", which causes the current process
963 id to be added to every log line, in square brackets, immediately after the
966 11. Exim has been modified so that it flushes SMTP output before implementing
967 a delay in an ACL. It also flushes the output before performing a callout,
968 as this can take a substantial time. These behaviours can be disabled by
969 obeying control = no_delay_flush or control = no_callout_flush,
970 respectively, at some earlier stage of the connection.
972 12. There are two new expansion conditions that iterate over a list. They are
973 called forany and forall.
975 13. There's a new global option called dsn_from that can be used to vary the
976 contents of From: lines in bounces and other automatically generated
977 messages ("delivery status notifications" - hence the name of the option).
979 14. The smtp transport has a new option called hosts_avoid_pipelining.
981 15. By default, exigrep does case-insensitive matches. There is now a -I option
982 that makes it case-sensitive.
984 16. A number of new features ("addresses", "map", "filter", and "reduce") have
985 been added to string expansions to make it easier to process lists of
986 items, typically addresses.
988 17. There's a new ACL modifier called "continue". It does nothing of itself,
989 and processing of the ACL always continues with the next condition or
990 modifier. It is provided so that the side effects of expanding its argument
993 18. It is now possible to use newline and other control characters (those with
994 values less than 32, plus DEL) as separators in lists.
996 19. The exigrep utility now has a -v option, which inverts the matching
999 20. The host_find_failed option in the manualroute router can now be set to
1006 No new features were added to 4.66.
1012 No new features were added to 4.65.
1018 1. ACL variables can now be given arbitrary names, as long as they start with
1019 "acl_c" or "acl_m" (for connection variables and message variables), are at
1020 least six characters long, with the sixth character being either a digit or
1023 2. There is a new ACL modifier called log_reject_target. It makes it possible
1024 to specify which logs are used for messages about ACL rejections.
1026 3. There is a new authenticator called "dovecot". This is an interface to the
1027 authentication facility of the Dovecot POP/IMAP server, which can support a
1028 number of authentication methods.
1030 4. The variable $message_headers_raw provides a concatenation of all the
1031 messages's headers without any decoding. This is in contrast to
1032 $message_headers, which does RFC2047 decoding on the header contents.
1034 5. In a DNS black list, if two domain names, comma-separated, are given, the
1035 second is used first to do an initial check, making use of any IP value
1036 restrictions that are set. If there is a match, the first domain is used,
1037 without any IP value restrictions, to get the TXT record.
1039 6. All authenticators now have a server_condition option.
1041 7. There is a new command-line option called -Mset. It is useful only in
1042 conjunction with -be (that is, when testing string expansions). It must be
1043 followed by a message id; Exim loads the given message from its spool
1044 before doing the expansions.
1046 8. Another similar new command-line option is called -bem. It operates like
1047 -be except that it must be followed by the name of a file that contains a
1050 9. When an address is delayed because of a 4xx response to a RCPT command, it
1051 is now the combination of sender and recipient that is delayed in
1052 subsequent queue runs until its retry time is reached.
1054 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1055 shift, have been added to the eval: and eval10: expansion items.
1057 11. The variables $interface_address and $interface_port have been renamed
1058 as $received_ip_address and $received_port, to make it clear that they
1059 relate to message reception rather than delivery. (The old names remain
1060 available for compatibility.)
1062 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1063 to vary the message that is sent when an SMTP command is accepted.
1069 1. There is a new Boolean option called filter_prepend_home for the redirect
1072 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1073 start of receiving a non-SMTP message, before any of the message has been
1076 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1077 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1078 start of the message for an SMTP error code.
1080 4. There is a new parameter for LDAP lookups called "referrals", which takes
1081 one of the settings "follow" (the default) or "nofollow".
1083 5. Version 20070721.2 of exipick now included, offering these new options:
1085 After all other sorting options have bee processed, reverse order
1086 before displaying messages (-R is synonym).
1088 Randomize order of matching messages before displaying.
1090 Instead of displaying the matching messages, display the sum
1092 --sort <variable>[,<variable>...]
1093 Before displaying matching messages, sort the messages according to
1094 each messages value for each variable.
1096 Negate the value for every test (returns inverse output from the
1097 same criteria without --not).
1103 1. The ${readsocket expansion item now supports Internet domain sockets as well
1104 as Unix domain sockets. If the first argument begins "inet:", it must be of
1105 the form "inet:host:port". The port is mandatory; it may be a number or the
1106 name of a TCP port in /etc/services. The host may be a name, or it may be an
1107 IP address. An ip address may optionally be enclosed in square brackets.
1108 This is best for IPv6 addresses. For example:
1110 ${readsocket{inet:[::1]:1234}{<request data>}...
1112 Only a single host name may be given, but if looking it up yield more than
1113 one IP address, they are each tried in turn until a connection is made. Once
1114 a connection has been made, the behaviour is as for ${readsocket with a Unix
1117 2. If a redirect router sets up file or pipe deliveries for more than one
1118 incoming address, and the relevant transport has batch_max set greater than
1119 one, a batch delivery now occurs.
1121 3. The appendfile transport has a new option called maildirfolder_create_regex.
1122 Its value is a regular expression. For a maildir delivery, this is matched
1123 against the maildir directory; if it matches, Exim ensures that a
1124 maildirfolder file is created alongside the new, cur, and tmp directories.
1130 The documentation is up-to-date for the 4.61 release. Major new features since
1131 the 4.60 release are:
1133 . An option called disable_ipv6, to disable the use of IPv6 completely.
1135 . An increase in the number of ACL variables to 20 of each type.
1137 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1138 $2, $3, (though those are still set) because the numeric variables get used
1139 for other things in complicated expansions.
1141 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1143 . It is possible to use setclassresources() on some BSD OS to control the
1144 resources used in pipe deliveries.
1146 . A new ACL modifier called add_header, which can be used with any verb.
1148 . More errors are detectable in retry rules.
1150 There are a number of other additions too.
1156 The documentation is up-to-date for the 4.60 release. Major new features since
1157 the 4.50 release are:
1159 . Support for SQLite.
1161 . Support for IGNOREQUOTA in LMTP.
1163 . Extensions to the "submission mode" features.
1165 . Support for Client SMTP Authorization (CSA).
1167 . Support for ratelimiting hosts and users.
1169 . New expansion items to help with the BATV "prvs" scheme.
1171 . A "match_ip" condition, that matches an IP address against a list.
1173 There are many more minor changes.
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