4 This file contains descriptions of new features that have been added to Exim.
5 Before a formal release, there may be quite a lot of detail so that people can
6 test from the snapshots or the Git before the documentation is updated. Once
7 the documentation is updated, this file is reduced to a short list.
12 1. Dual-certificate stacks on servers now support OCSP stapling, under GnuTLS
13 version 3.5.6 or later.
15 2. DANE is now supported under GnuTLS version 3.0.0 or later (adding to the
16 previous OpenSSL implementation, but still Experimental).
18 3. Feature macros for the compiled-in set of malware scanner interfaces.
20 4. SPF support is promoted from Experimental to mainline status. The template
21 src/EDITME makefile does not enable its inclusion.
27 1. PKG_CONFIG_PATH can now be set in Local/Makefile;
28 wildcards will be expanded, values are collapsed.
30 2. The ${readsocket } expansion now takes an option to not shutdown the
31 connection after sending the query string. The default remains to do so.
33 3. An smtp transport option "hosts_noproxy_tls" to control whether multiple
34 deliveries on a single TCP connection can maintain a TLS connection
35 open. By default disabled for all hosts, doing so saves the cost of
36 making new TLS sessions, at the cost of having to proxy the data via
37 another process. Logging is also affected.
39 4. A malware connection type for the FPSCAND protocol.
41 5. An option for recipient verify callouts to hold the connection open for
42 further recipients and for delivery.
44 6. The reproducible build $SOURCE_DATE_EPOCH environment variable is now
47 7. Optionally, an alternate format for spool data-files which matches the
48 wire format - meaning more efficient reception and transmission (at the
49 cost of difficulty with standard Unix tools). Only used for messages
50 received using the ESMTP CHUNKING option, and when a new main-section
51 option "spool_wireformat" (false by default) is set.
53 8. New main configuration option "commandline_checks_require_admin" to
54 restrict who can use various introspection options.
56 9. New option modifier "no_check" for quota and quota_filecount
59 10. Variable $smtp_command_history returning a comma-sep list of recent
62 11. Millisecond timetamps in logs, on log_selector "millisec". Also affects
63 log elements QT, DT and D, and timstamps in debug output.
65 12. TCP Fast Open logging. As a server, logs when the SMTP banner was sent
66 while still in SYN_RECV state; as a client logs when the connection
67 is opened with a TFO cookie.
69 13. DKIM support for multiple signing, by domain and/or key-selector.
70 DKIM support for multiple hashes, and for alternate-identity tags.
71 Builtin macro with default list of signed headers.
72 Better syntax for specifying oversigning.
73 The DKIM ACL can override verification status, and status is visible in
76 14. Exipick understands -C|--config for an alternative Exim
79 15. TCP Fast Open used, with data-on-SYN, for client SMTP via SOCKS5 proxy,
80 for ${readsocket } expansions, and for ClamAV.
82 16. The "-be" expansion test mode now supports macros. Macros are expanded
83 in test lines, and new macros can be defined.
85 17. Support for server-side dual-certificate-stacks (eg. RSA + ECDSA).
91 1. Allow relative config file names for ".include"
93 2. A main-section config option "debug_store" to control the checks on
94 variable locations during store-reset. Normally false but can be enabled
95 when a memory corrution issue is suspected on a production system.
101 1. The new perl_taintmode option allows to run the embedded perl
102 interpreter in taint mode.
104 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
106 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
109 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
110 N can be 224, 256 (default), 384, 512.
111 With GnuTLS 3.5.0 or later, only.
113 5. Facility for named queues: A command-line argument can specify
114 the queue name for a queue operation, and an ACL modifier can set
115 the queue to be used for a message. A $queue_name variable gives
118 6. New expansion operators base32/base32d.
120 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
121 performance increase and network load decrease. Main config option
122 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
125 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
127 9. Expansion operator escape8bit, like escape but not touching newline etc..
129 10. Feature macros, generated from compile options. All start with "_HAVE_"
130 and go on with some roughly recognisable name. Driver macros, for
131 router, transport and authentication drivers; names starting with "_DRIVER_".
132 Option macros, for each configuration-file option; all start with "_OPT_".
133 Use the "-bP macros" command-line option to see what is present.
135 11. Integer values for options can take a "G" multiplier.
137 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
138 returns from the target back to the initiator, rather than spooling the
141 13. New built-in constants available for tls_dhparam and default changed.
143 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
144 out copies of the message spool files for use by 3rd-party scanners.
146 15. A new option on the smtp transport, hosts_try_fastopen. If the system
147 supports it (on Linux it must be enabled in the kernel by the sysadmin)
148 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
149 but it permits a peer that also supports the facility to send its SMTP
150 banner immediately after the SYN,ACK segment rather then waiting for
151 another ACK - so saving up to one roundtrip time. Because it requires
152 previous communication with the peer (we save a cookie from it) this
153 will only become active on frequently-contacted destinations.
155 16. A new syslog_pid option to suppress PID duplication in syslog lines.
161 1. The ACL conditions regex and mime_regex now capture substrings
162 into numeric variables $regex1 to 9, like the "match" expansion condition.
164 2. New $callout_address variable records the address used for a spam=,
165 malware= or verify= callout.
167 3. Transports now take a "max_parallel" option, to limit concurrency.
169 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
170 The latter expands to a 8-element colon-sep set of hex digits including
171 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
172 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
173 The former operator strips leading zeroes and collapses the longest
174 set of 0-groups to a double-colon.
176 5. New "-bP config" support, to dump the effective configuration.
178 6. New $dkim_key_length variable.
180 7. New base64d and base64 expansion items (the existing str2b64 being a
181 synonym of the latter). Add support in base64 for certificates.
183 8. New main configuration option "bounce_return_linesize_limit" to
184 avoid oversize bodies in bounces. The default value matches RFC
187 9. New $initial_cwd expansion variable.
193 1. Support for using the system standard CA bundle.
195 2. New expansion items $config_file, $config_dir, containing the file
196 and directory name of the main configuration file. Also $exim_version.
198 3. New "malware=" support for Avast.
200 4. New "spam=" variant option for Rspamd.
202 5. Assorted options on malware= and spam= scanners.
204 6. A command-line option to write a comment into the logfile.
206 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
207 be configured to make connections via socks5 proxies.
209 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
210 the transmission of UTF-8 envelope addresses.
212 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
213 used encoding of Maildir folder names.
215 10. A logging option for slow DNS lookups.
217 11. New ${env {<variable>}} expansion.
219 12. A non-SMTP authenticator using information from TLS client certificates.
221 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
222 Patch originally by Wolfgang Breyha.
224 14. Main option "dns_trust_aa" for trusting your local nameserver at the
225 same level as DNSSEC.
231 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
232 DANE SMTP draft to assess a secure chain of trust of the certificate
233 used to establish the TLS connection based on a TLSA record in the
234 domain of the sender.
236 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
237 and several new events have been created. The reason is because it has
238 been expanded beyond just firing events during the transport phase. Any
239 existing TPDA transport options will have to be rewritten to use a new
240 $event_name expansion variable in a condition. Refer to the
241 experimental-spec.txt for details and examples.
243 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
244 server certs used for TLS match the result of the MX lookup. It does
245 not use the same mechanism as DANE.
255 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
256 configured to expect an initial header from a proxy that will make the
257 actual external source IP:host be used in exim instead of the IP of the
258 proxy that is connecting to it.
260 2. New verify option header_names_ascii, which will check to make sure
261 there are no non-ASCII characters in header names. Exim itself handles
262 those non-ASCII characters, but downstream apps may not, so Exim can
263 detect and reject if those characters are present.
265 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
266 codepoints with valid ones.
268 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
269 command line and matching a regex against the return data for trigger
270 and a second regex to extract malware_name. The mail spoolfile name can
271 be included in the command line.
273 5. The smtp transport now supports options "tls_verify_hosts" and
274 "tls_try_verify_hosts". If either is set the certificate verification
275 is split from the encryption operation. The default remains that a failed
276 verification cancels the encryption.
278 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
279 lookup can now set a list of servers to use that is different from the
282 7. New command-line option -C for exiqgrep to specify alternate exim.conf
283 file when searching the queue.
285 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
287 9. Support for DNSSEC on outbound connections.
289 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
290 "certextract" to extract fields from them. Hash operators md5 and sha1
291 work over them for generating fingerprints, and a new sha256 operator
294 11. PRDR is now supported dy default.
296 12. OCSP stapling is now supported by default.
298 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
299 Delivery Status Notification messages in MIME format, and negotiate
300 DSN features per RFC 3461.
306 1. New command-line option -bI:sieve will list all supported sieve extensions
307 of this Exim build on standard output, one per line.
308 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
309 query this to establish the correct list to include in the protocol's
310 SIEVE capability line.
312 2. If the -n option is combined with the -bP option, then the name of an
313 emitted option is not output, only the value (if visible to you).
314 For instance, "exim -n -bP pid_file_path" should just emit a pathname
315 followed by a newline, and no other text.
317 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
318 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
319 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
320 acceptable for security. (Option accepted but ignored if using OpenSSL).
321 Defaults to 1024, the old value. May be lowered only to 512, or raised as
322 far as you like. Raising this may hinder TLS interoperability with other
323 sites and is not currently recommended. Lowering this will permit you to
324 establish a TLS session which is not as secure as you might like.
326 Unless you really know what you are doing, leave it alone.
328 4. If not built with DISABLE_DNSSEC, Exim now has the main option
329 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
330 to send the DO flag to your recursive resolver. If you have a recursive
331 resolver, which can set the Authenticated Data (AD) flag in results, Exim
332 can now detect this. Exim does not perform validation itself, instead
333 relying upon a trusted path to the resolver.
335 Current status: work-in-progress; $sender_host_dnssec variable added.
337 5. DSCP support for outbound connections: on a transport using the smtp driver,
338 set "dscp = ef", for instance, to cause the connections to have the relevant
339 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
341 Similarly for inbound connections, there is a new control modifier, dscp,
342 so "warn control = dscp/ef" in the connect ACL, or after authentication.
344 Supported values depend upon system libraries. "exim -bI:dscp" to list the
345 ones Exim knows of. You can also set a raw number 0..0x3F.
347 6. The -G command-line flag is no longer ignored; it is now equivalent to an
348 ACL setting "control = suppress_local_fixups". The -L command-line flag
349 is now accepted and forces use of syslog, with the provided tag as the
350 process name. A few other flags used by Sendmail are now accepted and
353 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
354 ACL modifier; works for single-recipient mails which are received on and
355 deliverable via SMTP. Using the connection made for a recipient verify,
356 if requested before the verify, or a new one made for the purpose while
357 the inbound connection is still active. The bulk of the mail item is copied
358 direct from the inbound socket to the outbound (as well as the spool file).
359 When the source notifies the end of data, the data acceptance by the destination
360 is negotiated before the acceptance is sent to the source. If the destination
361 does not accept the mail item, for example due to content-scanning, the item
362 is not accepted from the source and therefore there is no need to generate
363 a bounce mail. This is of benefit when providing a secondary-MX service.
364 The downside is that delays are under the control of the ultimate destination
367 The Received-by: header on items delivered by cutthrough is generated
368 early in reception rather than at the end; this will affect any timestamp
369 included. The log line showing delivery is recorded before that showing
370 reception; it uses a new ">>" tag instead of "=>".
372 To support the feature, verify-callout connections can now use ESMTP and TLS.
373 The usual smtp transport options are honoured, plus a (new, default everything)
374 hosts_verify_avoid_tls.
376 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
377 for specific access to the information for each connection. The old names
378 are present for now but deprecated.
380 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
382 8. New expansion operators ${listnamed:name} to get the content of a named list
383 and ${listcount:string} to count the items in a list.
385 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
386 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
387 modules. For some situations this is desirable, but we expect admin in
388 those situations to know they want the feature. More commonly, it means
389 that GUI user modules get loaded and are broken by the setuid Exim being
390 unable to access files specified in environment variables and passed
391 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
392 unless this new option is set.
394 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
395 so have also added a build option which can be used to build Exim with GnuTLS
396 but without trying to use any kind of PKCS11 support. Uncomment this in the
399 AVOID_GNUTLS_PKCS11=yes
401 10. The "acl = name" condition on an ACL now supports optional arguments.
402 New expansion item "${acl {name}{arg}...}" and expansion condition
403 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
404 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
405 Variable $acl_narg contains the number of arguments. If the ACL sets
406 a "message =" value this becomes the result of the expansion item,
407 or the value of $value for the expansion condition. If the ACL returns
408 accept the expansion condition is true; if reject, false. A defer
409 return results in a forced fail.
411 11. Routers and transports can now have multiple headers_add and headers_remove
412 option lines. The concatenated list is used.
414 12. New ACL modifier "remove_header" can remove headers before message gets
415 handled by routers/transports.
417 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
418 "aaaa" and "a" lookups is done and the full set of results returned.
420 14. New expansion variable $headers_added with content from ACL add_header
421 modifier (but not yet added to message).
423 15. New 8bitmime status logging option for received messages. Log field "M8S".
425 16. New authenticated_sender logging option, adding to log field "A".
427 17. New expansion variables $router_name and $transport_name. Useful
428 particularly for debug_print as -bt command-line option does not
429 require privilege whereas -d does.
431 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
432 proposed extension to SMTP from Eric Hall.
434 19. The pipe transport has gained the force_command option, to allow
435 decorating commands from user .forward pipe aliases with prefix
436 wrappers, for instance.
438 20. Callout connections can now AUTH; the same controls as normal delivery
441 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
442 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
443 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
444 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
445 dmarc_status. It adds new control flags dmarc_disable_verify and
446 dmarc_enable_forensic. The default for the dmarc_tld_file option is
447 "/etc/exim/opendmarc.tlds" and can be changed via EDITME.
449 22. Add expansion variable $authenticated_fail_id, which is the username
450 provided to the authentication method which failed. It is available
451 for use in subsequent ACL processing (typically quit or notquit ACLs).
453 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
456 24. New ${hexquote:..string..} expansion operator converts non-printable
457 characters in the string to \xNN form.
459 25. Experimental TPDA (Transport Post Delivery Action) function added.
460 Patch provided by Axel Rau.
462 26. Experimental Redis lookup added. Patch provided by Warren Baker.
468 1. New authenticator driver, "gsasl". Server-only (at present).
469 This is a SASL interface, licensed under GPL, which can be found at
470 http://www.gnu.org/software/gsasl/.
471 This system does not provide sources of data for authentication, so
472 careful use needs to be made of the conditions in Exim.
474 2. New authenticator driver, "heimdal_gssapi". Server-only.
475 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
476 is no longer honoured for setuid programs by Heimdal. Use the
477 "server_keytab" option to point to the keytab.
479 3. The "pkg-config" system can now be used when building Exim to reference
480 cflags and library information for lookups and authenticators, rather
481 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
482 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
483 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
485 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
486 find the headers and libraries for PCRE.
488 4. New expansion variable $tls_bits.
490 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
491 be joined together with ASCII NUL characters to construct the key to pass
492 into the DBM library. Can be used with gsasl to access sasldb2 files as
495 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
497 Avoid release 1.0.1a if you can. Note that the default value of
498 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
499 increased susceptibility to attack. This may still have interoperability
500 implications for very old clients (see version 4.31 change 37) but
501 administrators can choose to make the trade-off themselves and restore
502 compatibility at the cost of session security.
504 7. Use of the new expansion variable $tls_sni in the main configuration option
505 tls_certificate will cause Exim to re-expand the option, if the client
506 sends the TLS Server Name Indication extension, to permit choosing a
507 different certificate; tls_privatekey will also be re-expanded. You must
508 still set these options to expand to valid files when $tls_sni is not set.
510 The SMTP Transport has gained the option tls_sni, which will set a hostname
511 for outbound TLS sessions, and set $tls_sni too.
513 A new log_selector, +tls_sni, has been added, to log received SNI values
514 for Exim as a server.
516 8. The existing "accept_8bitmime" option now defaults to true. This means
517 that Exim is deliberately not strictly RFC compliant. We're following
518 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
519 Those who disagree, or know that they are talking to mail servers that,
520 even today, are not 8-bit clean, need to turn off this option.
522 9. Exim can now be started with -bw (with an optional timeout, given as
523 -bw<timespec>). With this, stdin at startup is a socket that is
524 already listening for connections. This has a more modern name of
525 "socket activation", but forcing the activated socket to fd 0. We're
526 interested in adding more support for modern variants.
528 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
529 for numbers indicates multiplication by 1024^3.
531 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
532 gnutls_require_mac & gnutls_require_protocols are no longer supported.
533 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
534 string, documentation for which is at:
535 http://www.gnutls.org/manual/html_node/Priority-Strings.html
537 SNI support has been added to Exim's GnuTLS integration too.
539 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
540 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
542 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
543 is now available. If the contents of the file are valid, then Exim will
544 send that back in response to a TLS status request; this is OCSP Stapling.
545 Exim will not maintain the contents of the file in any way: administrators
546 are responsible for ensuring that it is up-to-date.
548 See "experimental-spec.txt" for more details.
550 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
551 identically to TXT record lookups.
553 14. New expansion variable $tod_epoch_l for higher-precision time.
555 15. New global option tls_dh_max_bits, defaulting to current value of NSS
556 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
557 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
559 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
560 Option can now be a path or an identifier for a standard prime.
561 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
562 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
565 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
566 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
567 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
573 1. New options for the ratelimit ACL condition: /count= and /unique=.
574 The /noupdate option has been replaced by a /readonly option.
576 2. The SMTP transport's protocol option may now be set to "smtps", to
577 use SSL-on-connect outbound.
579 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
580 there is a problem talking to the AV scanner, or the AV scanner running.
582 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
583 and check if the search item is a member of the list. This does not
584 support named lists, but does subject the list part to string expansion.
586 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
587 built, Exim no longer performs string expansion on the second string of
588 the match_* expansion conditions: "match_address", "match_domain",
589 "match_ip" & "match_local_part". Named lists can still be used.
595 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
596 or off in the resolver library.
602 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
603 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
604 libraries. The following global options have been added in support of
605 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
606 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
608 2. The pipe transport now takes a boolean option, "freeze_signal", default
609 false. When true, if the external delivery command exits on a signal then
610 Exim will freeze the message in the queue, instead of generating a bounce.
612 3. Log filenames may now use %M as an escape, instead of %D (still available).
613 The %M pattern expands to yyyymm, providing month-level resolution.
615 4. The $message_linecount variable is now updated for the maildir_tag option,
616 in the same way as $message_size, to reflect the real number of lines,
617 including any header additions or removals from transport.
619 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
620 Exim now selects entries randomly, to better scale in a cluster setup.
626 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
627 the flaw permitted the Exim run-time user to cause root to append to
628 arbitrary files of the attacker's choosing, with the content based
629 on content supplied by the attacker.
631 2. Exim now supports loading some lookup types at run-time, using your
632 platform's dlopen() functionality. This has limited platform support
633 and the intention is not to support every variant, it's limited to
634 dlopen(). This permits the main Exim binary to not be linked against
635 all the libraries needed for all the lookup types.
641 NOTE: this version is not guaranteed backwards-compatible, please read the
642 items below carefully
644 1. A new main configuration option, "openssl_options", is available if Exim
645 is built with SSL support provided by OpenSSL. The option allows
646 administrators to specify OpenSSL options to be used on connections;
647 typically this is to set bug compatibility features which the OpenSSL
648 developers have not enabled by default. There may be security
649 consequences for certain options, so these should not be changed
652 2. A new pipe transport option, "permit_coredumps", may help with problem
653 diagnosis in some scenarios. Note that Exim is typically installed as
654 a setuid binary, which on most OSes will inhibit coredumps by default,
655 so that safety mechanism would have to be overridden for this option to
656 be able to take effect.
658 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
659 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
660 Note that this switches Exim to use a new API ("INSTREAM") and a future
661 release of ClamAV will remove support for the old API ("STREAM").
663 The av_scanner option, when set to "clamd", now takes an optional third
664 part, "local", which causes Exim to pass a filename to ClamAV instead of
665 the file content. This is the same behaviour as when clamd is pointed at
666 a Unix-domain socket. For example:
668 av_scanner = clamd:192.0.2.3 1234:local
670 ClamAV's ExtendedDetectionInfo response format is now handled.
672 4. There is now a -bmalware option, restricted to admin users. This option
673 takes one parameter, a filename, and scans that file with Exim's
674 malware-scanning framework. This is intended purely as a debugging aid
675 to ensure that Exim's scanning is working, not to replace other tools.
676 Note that the ACL framework is not invoked, so if av_scanner references
677 ACL variables without a fallback then this will fail.
679 5. There is a new expansion operator, "reverse_ip", which will reverse IP
680 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
682 ${reverse_ip:192.0.2.4}
684 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
685 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
687 6. There is a new ACL control called "debug", to enable debug logging.
688 This allows selective logging of certain incoming transactions within
689 production environments, with some care. It takes two options, "tag"
690 and "opts"; "tag" is included in the filename of the log and "opts"
691 is used as per the -d<options> command-line option. Examples, which
692 don't all make sense in all contexts:
695 control = debug/tag=.$sender_host_address
696 control = debug/opts=+expand+acl
697 control = debug/tag=.$message_exim_id/opts=+expand
699 7. It has always been implicit in the design and the documentation that
700 "the Exim user" is not root. src/EDITME said that using root was
701 "very strongly discouraged". This is not enough to keep people from
702 shooting themselves in the foot in days when many don't configure Exim
703 themselves but via package build managers. The security consequences of
704 running various bits of network code are severe if there should be bugs in
705 them. As such, the Exim user may no longer be root. If configured
706 statically, Exim will refuse to build. If configured as ref:user then Exim
707 will exit shortly after start-up. If you must shoot yourself in the foot,
708 then henceforth you will have to maintain your own local patches to strip
711 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
712 condition logic to determine truth/failure and will fail to expand many
713 strings, bool_lax{} uses the router condition logic, where most strings
715 Note: bool{00} is false, bool_lax{00} is true.
717 9. Routers now support multiple "condition" tests.
719 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
720 Setting this allows an admin to define which entry in the tcpwrappers
721 config file will be used to control access to the daemon. This option
722 is only available when Exim is built with USE_TCP_WRAPPERS. The
723 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
726 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
727 the Exim run-time user, instead of root.
729 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
730 is forced on. This is mitigated by the new build option
731 TRUSTED_CONFIG_LIST which defines a list of configuration files which
732 are trusted; one per line. If a config file is owned by root and matches
733 a pathname in the list, then it may be invoked by the Exim build-time
734 user without Exim relinquishing root privileges.
736 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
737 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
738 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
739 include the main config. As a transition mechanism, we are temporarily
740 providing a work-around: the new build option WHITELIST_D_MACROS provides
741 a colon-separated list of macro names which may be overridden by the Exim
742 run-time user. The values of these macros are constrained to the regex
743 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
749 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
750 writable, the other to locking of MBX folders (not mbox).
752 2. MySQL stored procedures are now supported.
754 3. The dkim_domain transport option is now a list, not a single string, and
755 messages will be signed for each element in the list (discarding
758 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
759 in the presence of multiple character strings within the RR. Prior to 4.70,
760 only the first string would be returned. The dnsdb lookup now, by default,
761 preserves the pre-4.70 semantics, but also now takes an extended output
762 separator specification. The separator can be followed by a semicolon, to
763 concatenate the individual text strings together with no join character,
764 or by a comma and a second separator character, in which case the text
765 strings within a TXT record are joined on that second character.
766 Administrators are reminded that DNS provides no ordering guarantees
767 between multiple records in an RRset. For example:
769 foo.example. IN TXT "a" "b" "c"
770 foo.example. IN TXT "d" "e" "f"
772 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
773 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
774 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
780 1. Native DKIM support without an external library.
781 (Note that if no action to prevent it is taken, a straight upgrade will
782 result in DKIM verification of all signed incoming emails. See spec
783 for details on conditionally disabling)
785 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
787 3. There is now a bool{} expansion condition which maps certain strings to
788 true/false condition values (most likely of use in conjunction with the
789 and{} expansion operator).
791 4. The $spam_score, $spam_bar and $spam_report variables are now available
794 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
795 options, provided that Exim is invoked by an admin_user.
797 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
798 which increases compatibility with older clients at the cost of decreased
799 security. Don't set this unless you need to support such clients.
801 7. There is a new expansion operator, ${randint:...} which will produce a
802 "random" number less than the supplied integer. This randomness is
803 not guaranteed to be cryptographically strong, but depending upon how
804 Exim was built may be better than the most naive schemes.
806 8. Exim now explicitly ensures that SHA256 is available when linked against
809 9. The transport_filter_timeout option now applies to SMTP transports too.
815 1. Preliminary DKIM support in Experimental.
821 1. The body_linecount and body_zerocount C variables are now exported in the
824 2. When a dnslists lookup succeeds, the key that was looked up is now placed
825 in $dnslist_matched. When the key is an IP address, it is not reversed in
826 this variable (though it is, of course, in the actual lookup). In simple
829 deny dnslists = spamhaus.example
831 the key is also available in another variable (in this case,
832 $sender_host_address). In more complicated cases, however, this is not
833 true. For example, using a data lookup might generate a dnslists lookup
836 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
838 If this condition succeeds, the value in $dnslist_matched might be
839 192.168.6.7 (for example).
841 3. Authenticators now have a client_condition option. When Exim is running as
842 a client, it skips an authenticator whose client_condition expansion yields
843 "0", "no", or "false". This can be used, for example, to skip plain text
844 authenticators when the connection is not encrypted by a setting such as:
846 client_condition = ${if !eq{$tls_cipher}{}}
848 Note that the 4.67 documentation states that $tls_cipher contains the
849 cipher used for incoming messages. In fact, during SMTP delivery, it
850 contains the cipher used for the delivery. The same is true for
853 4. There is now a -Mvc <message-id> option, which outputs a copy of the
854 message to the standard output, in RFC 2822 format. The option can be used
855 only by an admin user.
857 5. There is now a /noupdate option for the ratelimit ACL condition. It
858 computes the rate and checks the limit as normal, but it does not update
859 the saved data. This means that, in relevant ACLs, it is possible to lookup
860 the existence of a specified (or auto-generated) ratelimit key without
861 incrementing the ratelimit counter for that key.
863 In order for this to be useful, another ACL entry must set the rate
864 for the same key somewhere (otherwise it will always be zero).
869 # Read the rate; if it doesn't exist or is below the maximum
871 deny ratelimit = 100 / 5m / strict / noupdate
872 log_message = RATE: $sender_rate / $sender_rate_period \
873 (max $sender_rate_limit)
875 [... some other logic and tests...]
877 warn ratelimit = 100 / 5m / strict / per_cmd
878 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
879 (max $sender_rate_limit)
880 condition = ${if le{$sender_rate}{$sender_rate_limit}}
884 6. The variable $max_received_linelength contains the number of bytes in the
885 longest line that was received as part of the message, not counting the
886 line termination character(s).
888 7. Host lists can now include +ignore_defer and +include_defer, analagous to
889 +ignore_unknown and +include_unknown. These options should be used with
890 care, probably only in non-critical host lists such as whitelists.
892 8. There's a new option called queue_only_load_latch, which defaults true.
893 If set false when queue_only_load is greater than zero, Exim re-evaluates
894 the load for each incoming message in an SMTP session. Otherwise, once one
895 message is queued, the remainder are also.
897 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
898 cases when an SMTP session ends without sending QUIT. However, when Exim
899 itself is is bad trouble, such as being unable to write to its log files,
900 this ACL is not run, because it might try to do things (such as write to
901 log files) that make the situation even worse.
903 Like the QUIT ACL, this new ACL is provided to make it possible to gather
904 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
905 modifier is forbidden in this ACL.
907 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
908 to a string that indicates the reason for the termination of the SMTP
909 connection. The possible values are:
911 acl-drop Another ACL issued a "drop" command
912 bad-commands Too many unknown or non-mail commands
913 command-timeout Timeout while reading SMTP commands
914 connection-lost The SMTP connection has been lost
915 data-timeout Timeout while reading message data
916 local-scan-error The local_scan() function crashed
917 local-scan-timeout The local_scan() function timed out
918 signal-exit SIGTERM or SIGINT
919 synchronization-error SMTP synchronization error
920 tls-failed TLS failed to start
922 In most cases when an SMTP connection is closed without having received
923 QUIT, Exim sends an SMTP response message before actually closing the
924 connection. With the exception of acl-drop, the default message can be
925 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
926 "drop" verb in another ACL, it is the message from the other ACL that is
929 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
930 servers with individual queries. This is done by starting the query with
931 "servers=x:y:z;", where each item in the list may take one of two forms:
933 (1) If it is just a host name, the appropriate global option (mysql_servers
934 or pgsql_servers) is searched for a host of the same name, and the
935 remaining parameters (database, user, password) are taken from there.
937 (2) If it contains any slashes, it is taken as a complete parameter set.
939 The list of servers is used in exactly the same was as the global list.
940 Once a connection to a server has happened and a query has been
941 successfully executed, processing of the lookup ceases.
943 This feature is intended for use in master/slave situations where updates
944 are occurring, and one wants to update a master rather than a slave. If the
945 masters are in the list for reading, you might have:
947 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
949 In an updating lookup, you could then write
951 ${lookup mysql{servers=master; UPDATE ...}
953 If, on the other hand, the master is not to be used for reading lookups:
955 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
957 you can still update the master by
959 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
961 11. The message_body_newlines option (default FALSE, for backwards
962 compatibility) can be used to control whether newlines are present in
963 $message_body and $message_body_end. If it is FALSE, they are replaced by
970 1. There is a new log selector called smtp_no_mail, which is not included in
971 the default setting. When it is set, a line is written to the main log
972 whenever an accepted SMTP connection terminates without having issued a
975 2. When an item in a dnslists list is followed by = and & and a list of IP
976 addresses, the behaviour was not clear when the lookup returned more than
977 one IP address. This has been solved by the addition of == and =& for "all"
978 rather than the default "any" matching.
980 3. Up till now, the only control over which cipher suites GnuTLS uses has been
981 for the cipher algorithms. New options have been added to allow some of the
982 other parameters to be varied.
984 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
985 set, Exim compiles a runtime option called disable_fsync.
987 5. There is a new variable called $smtp_count_at_connection_start.
989 6. There's a new control called no_pipelining.
991 7. There are two new variables called $sending_ip_address and $sending_port.
992 These are set whenever an SMTP connection to another host has been set up.
994 8. The expansion of the helo_data option in the smtp transport now happens
995 after the connection to the server has been made.
997 9. There is a new expansion operator ${rfc2047d: that decodes strings that
998 are encoded as per RFC 2047.
1000 10. There is a new log selector called "pid", which causes the current process
1001 id to be added to every log line, in square brackets, immediately after the
1004 11. Exim has been modified so that it flushes SMTP output before implementing
1005 a delay in an ACL. It also flushes the output before performing a callout,
1006 as this can take a substantial time. These behaviours can be disabled by
1007 obeying control = no_delay_flush or control = no_callout_flush,
1008 respectively, at some earlier stage of the connection.
1010 12. There are two new expansion conditions that iterate over a list. They are
1011 called forany and forall.
1013 13. There's a new global option called dsn_from that can be used to vary the
1014 contents of From: lines in bounces and other automatically generated
1015 messages ("delivery status notifications" - hence the name of the option).
1017 14. The smtp transport has a new option called hosts_avoid_pipelining.
1019 15. By default, exigrep does case-insensitive matches. There is now a -I option
1020 that makes it case-sensitive.
1022 16. A number of new features ("addresses", "map", "filter", and "reduce") have
1023 been added to string expansions to make it easier to process lists of
1024 items, typically addresses.
1026 17. There's a new ACL modifier called "continue". It does nothing of itself,
1027 and processing of the ACL always continues with the next condition or
1028 modifier. It is provided so that the side effects of expanding its argument
1031 18. It is now possible to use newline and other control characters (those with
1032 values less than 32, plus DEL) as separators in lists.
1034 19. The exigrep utility now has a -v option, which inverts the matching
1037 20. The host_find_failed option in the manualroute router can now be set to
1044 No new features were added to 4.66.
1050 No new features were added to 4.65.
1056 1. ACL variables can now be given arbitrary names, as long as they start with
1057 "acl_c" or "acl_m" (for connection variables and message variables), are at
1058 least six characters long, with the sixth character being either a digit or
1061 2. There is a new ACL modifier called log_reject_target. It makes it possible
1062 to specify which logs are used for messages about ACL rejections.
1064 3. There is a new authenticator called "dovecot". This is an interface to the
1065 authentication facility of the Dovecot POP/IMAP server, which can support a
1066 number of authentication methods.
1068 4. The variable $message_headers_raw provides a concatenation of all the
1069 messages's headers without any decoding. This is in contrast to
1070 $message_headers, which does RFC2047 decoding on the header contents.
1072 5. In a DNS black list, if two domain names, comma-separated, are given, the
1073 second is used first to do an initial check, making use of any IP value
1074 restrictions that are set. If there is a match, the first domain is used,
1075 without any IP value restrictions, to get the TXT record.
1077 6. All authenticators now have a server_condition option.
1079 7. There is a new command-line option called -Mset. It is useful only in
1080 conjunction with -be (that is, when testing string expansions). It must be
1081 followed by a message id; Exim loads the given message from its spool
1082 before doing the expansions.
1084 8. Another similar new command-line option is called -bem. It operates like
1085 -be except that it must be followed by the name of a file that contains a
1088 9. When an address is delayed because of a 4xx response to a RCPT command, it
1089 is now the combination of sender and recipient that is delayed in
1090 subsequent queue runs until its retry time is reached.
1092 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1093 shift, have been added to the eval: and eval10: expansion items.
1095 11. The variables $interface_address and $interface_port have been renamed
1096 as $received_ip_address and $received_port, to make it clear that they
1097 relate to message reception rather than delivery. (The old names remain
1098 available for compatibility.)
1100 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1101 to vary the message that is sent when an SMTP command is accepted.
1107 1. There is a new Boolean option called filter_prepend_home for the redirect
1110 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1111 start of receiving a non-SMTP message, before any of the message has been
1114 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1115 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1116 start of the message for an SMTP error code.
1118 4. There is a new parameter for LDAP lookups called "referrals", which takes
1119 one of the settings "follow" (the default) or "nofollow".
1121 5. Version 20070721.2 of exipick now included, offering these new options:
1123 After all other sorting options have bee processed, reverse order
1124 before displaying messages (-R is synonym).
1126 Randomize order of matching messages before displaying.
1128 Instead of displaying the matching messages, display the sum
1130 --sort <variable>[,<variable>...]
1131 Before displaying matching messages, sort the messages according to
1132 each messages value for each variable.
1134 Negate the value for every test (returns inverse output from the
1135 same criteria without --not).
1141 1. The ${readsocket expansion item now supports Internet domain sockets as well
1142 as Unix domain sockets. If the first argument begins "inet:", it must be of
1143 the form "inet:host:port". The port is mandatory; it may be a number or the
1144 name of a TCP port in /etc/services. The host may be a name, or it may be an
1145 IP address. An ip address may optionally be enclosed in square brackets.
1146 This is best for IPv6 addresses. For example:
1148 ${readsocket{inet:[::1]:1234}{<request data>}...
1150 Only a single host name may be given, but if looking it up yield more than
1151 one IP address, they are each tried in turn until a connection is made. Once
1152 a connection has been made, the behaviour is as for ${readsocket with a Unix
1155 2. If a redirect router sets up file or pipe deliveries for more than one
1156 incoming address, and the relevant transport has batch_max set greater than
1157 one, a batch delivery now occurs.
1159 3. The appendfile transport has a new option called maildirfolder_create_regex.
1160 Its value is a regular expression. For a maildir delivery, this is matched
1161 against the maildir directory; if it matches, Exim ensures that a
1162 maildirfolder file is created alongside the new, cur, and tmp directories.
1168 The documentation is up-to-date for the 4.61 release. Major new features since
1169 the 4.60 release are:
1171 . An option called disable_ipv6, to disable the use of IPv6 completely.
1173 . An increase in the number of ACL variables to 20 of each type.
1175 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1176 $2, $3, (though those are still set) because the numeric variables get used
1177 for other things in complicated expansions.
1179 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1181 . It is possible to use setclassresources() on some BSD OS to control the
1182 resources used in pipe deliveries.
1184 . A new ACL modifier called add_header, which can be used with any verb.
1186 . More errors are detectable in retry rules.
1188 There are a number of other additions too.
1194 The documentation is up-to-date for the 4.60 release. Major new features since
1195 the 4.50 release are:
1197 . Support for SQLite.
1199 . Support for IGNOREQUOTA in LMTP.
1201 . Extensions to the "submission mode" features.
1203 . Support for Client SMTP Authorization (CSA).
1205 . Support for ratelimiting hosts and users.
1207 . New expansion items to help with the BATV "prvs" scheme.
1209 . A "match_ip" condition, that matches an IP address against a list.
1211 There are many more minor changes.
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