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.
22 1. Allow relative config file names for ".include"
24 2. A main-section config option "debug_store" to control the checks on
25 variable locations during store-reset. Normally false but can be enabled
26 when a memory corrution issue is suspected on a production system.
32 1. The new perl_taintmode option allows to run the embedded perl
33 interpreter in taint mode.
35 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
37 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
40 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
41 N can be 224, 256 (default), 384, 512.
42 With GnuTLS 3.5.0 or later, only.
44 5. Facility for named queues: A command-line argument can specify
45 the queue name for a queue operation, and an ACL modifier can set
46 the queue to be used for a message. A $queue_name variable gives
49 6. New expansion operators base32/base32d.
51 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
52 performance increase and network load decrease. Main config option
53 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
56 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
58 9. Expansion operator escape8bit, like escape but not touching newline etc..
60 10. Feature macros, generated from compile options. All start with "_HAVE_"
61 and go on with some roughly recognisable name. Driver macros, for
62 router, transport and authentication drivers; names starting with "_DRIVER_".
63 Option macros, for each configuration-file option; all start with "_OPT_".
64 Use the "-bP macros" command-line option to see what is present.
66 11. Integer values for options can take a "G" multiplier.
68 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
69 returns from the target back to the initiator, rather than spooling the
72 13. New built-in constants available for tls_dhparam and default changed.
74 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
75 out copies of the message spool files for use by 3rd-party scanners.
77 15. A new option on the smtp transport, hosts_try_fastopen. If the system
78 supports it (on Linux it must be enabled in the kernel by the sysadmin)
79 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
80 but it permits a peer that also supports the facility to send its SMTP
81 banner immediately after the SYN,ACK segment rather then waiting for
82 another ACK - so saving up to one roundtrip time. Because it requires
83 previous communication with the peer (we save a cookie from it) this
84 will only become active on frequently-contacted destinations.
86 16. A new syslog_pid option to suppress PID duplication in syslog lines.
92 1. The ACL conditions regex and mime_regex now capture substrings
93 into numeric variables $regex1 to 9, like the "match" expansion condition.
95 2. New $callout_address variable records the address used for a spam=,
96 malware= or verify= callout.
98 3. Transports now take a "max_parallel" option, to limit concurrency.
100 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
101 The latter expands to a 8-element colon-sep set of hex digits including
102 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
103 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
104 The former operator strips leading zeroes and collapses the longest
105 set of 0-groups to a double-colon.
107 5. New "-bP config" support, to dump the effective configuration.
109 6. New $dkim_key_length variable.
111 7. New base64d and base64 expansion items (the existing str2b64 being a
112 synonym of the latter). Add support in base64 for certificates.
114 8. New main configuration option "bounce_return_linesize_limit" to
115 avoid oversize bodies in bounces. The default value matches RFC
118 9. New $initial_cwd expansion variable.
124 1. Support for using the system standard CA bundle.
126 2. New expansion items $config_file, $config_dir, containing the file
127 and directory name of the main configuration file. Also $exim_version.
129 3. New "malware=" support for Avast.
131 4. New "spam=" variant option for Rspamd.
133 5. Assorted options on malware= and spam= scanners.
135 6. A command-line option to write a comment into the logfile.
137 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
138 be configured to make connections via socks5 proxies.
140 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
141 the transmission of UTF-8 envelope addresses.
143 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
144 used encoding of Maildir folder names.
146 10. A logging option for slow DNS lookups.
148 11. New ${env {<variable>}} expansion.
150 12. A non-SMTP authenticator using information from TLS client certificates.
152 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
153 Patch originally by Wolfgang Breyha.
155 14. Main option "dns_trust_aa" for trusting your local nameserver at the
156 same level as DNSSEC.
162 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
163 DANE SMTP draft to assess a secure chain of trust of the certificate
164 used to establish the TLS connection based on a TLSA record in the
165 domain of the sender.
167 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
168 and several new events have been created. The reason is because it has
169 been expanded beyond just firing events during the transport phase. Any
170 existing TPDA transport options will have to be rewritten to use a new
171 $event_name expansion variable in a condition. Refer to the
172 experimental-spec.txt for details and examples.
174 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
175 server certs used for TLS match the result of the MX lookup. It does
176 not use the same mechanism as DANE.
186 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
187 configured to expect an initial header from a proxy that will make the
188 actual external source IP:host be used in exim instead of the IP of the
189 proxy that is connecting to it.
191 2. New verify option header_names_ascii, which will check to make sure
192 there are no non-ASCII characters in header names. Exim itself handles
193 those non-ASCII characters, but downstream apps may not, so Exim can
194 detect and reject if those characters are present.
196 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
197 codepoints with valid ones.
199 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
200 command line and matching a regex against the return data for trigger
201 and a second regex to extract malware_name. The mail spoolfile name can
202 be included in the command line.
204 5. The smtp transport now supports options "tls_verify_hosts" and
205 "tls_try_verify_hosts". If either is set the certificate verification
206 is split from the encryption operation. The default remains that a failed
207 verification cancels the encryption.
209 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
210 lookup can now set a list of servers to use that is different from the
213 7. New command-line option -C for exiqgrep to specify alternate exim.conf
214 file when searching the queue.
216 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
218 9. Support for DNSSEC on outbound connections.
220 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
221 "certextract" to extract fields from them. Hash operators md5 and sha1
222 work over them for generating fingerprints, and a new sha256 operator
225 11. PRDR is now supported dy default.
227 12. OCSP stapling is now supported by default.
229 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
230 Delivery Status Notification messages in MIME format, and negotiate
231 DSN features per RFC 3461.
237 1. New command-line option -bI:sieve will list all supported sieve extensions
238 of this Exim build on standard output, one per line.
239 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
240 query this to establish the correct list to include in the protocol's
241 SIEVE capability line.
243 2. If the -n option is combined with the -bP option, then the name of an
244 emitted option is not output, only the value (if visible to you).
245 For instance, "exim -n -bP pid_file_path" should just emit a pathname
246 followed by a newline, and no other text.
248 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
249 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
250 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
251 acceptable for security. (Option accepted but ignored if using OpenSSL).
252 Defaults to 1024, the old value. May be lowered only to 512, or raised as
253 far as you like. Raising this may hinder TLS interoperability with other
254 sites and is not currently recommended. Lowering this will permit you to
255 establish a TLS session which is not as secure as you might like.
257 Unless you really know what you are doing, leave it alone.
259 4. If not built with DISABLE_DNSSEC, Exim now has the main option
260 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
261 to send the DO flag to your recursive resolver. If you have a recursive
262 resolver, which can set the Authenticated Data (AD) flag in results, Exim
263 can now detect this. Exim does not perform validation itself, instead
264 relying upon a trusted path to the resolver.
266 Current status: work-in-progress; $sender_host_dnssec variable added.
268 5. DSCP support for outbound connections: on a transport using the smtp driver,
269 set "dscp = ef", for instance, to cause the connections to have the relevant
270 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
272 Similarly for inbound connections, there is a new control modifier, dscp,
273 so "warn control = dscp/ef" in the connect ACL, or after authentication.
275 Supported values depend upon system libraries. "exim -bI:dscp" to list the
276 ones Exim knows of. You can also set a raw number 0..0x3F.
278 6. The -G command-line flag is no longer ignored; it is now equivalent to an
279 ACL setting "control = suppress_local_fixups". The -L command-line flag
280 is now accepted and forces use of syslog, with the provided tag as the
281 process name. A few other flags used by Sendmail are now accepted and
284 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
285 ACL modifier; works for single-recipient mails which are received on and
286 deliverable via SMTP. Using the connection made for a recipient verify,
287 if requested before the verify, or a new one made for the purpose while
288 the inbound connection is still active. The bulk of the mail item is copied
289 direct from the inbound socket to the outbound (as well as the spool file).
290 When the source notifies the end of data, the data acceptance by the destination
291 is negotiated before the acceptance is sent to the source. If the destination
292 does not accept the mail item, for example due to content-scanning, the item
293 is not accepted from the source and therefore there is no need to generate
294 a bounce mail. This is of benefit when providing a secondary-MX service.
295 The downside is that delays are under the control of the ultimate destination
298 The Received-by: header on items delivered by cutthrough is generated
299 early in reception rather than at the end; this will affect any timestamp
300 included. The log line showing delivery is recorded before that showing
301 reception; it uses a new ">>" tag instead of "=>".
303 To support the feature, verify-callout connections can now use ESMTP and TLS.
304 The usual smtp transport options are honoured, plus a (new, default everything)
305 hosts_verify_avoid_tls.
307 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
308 for specific access to the information for each connection. The old names
309 are present for now but deprecated.
311 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
313 8. New expansion operators ${listnamed:name} to get the content of a named list
314 and ${listcount:string} to count the items in a list.
316 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
317 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
318 modules. For some situations this is desirable, but we expect admin in
319 those situations to know they want the feature. More commonly, it means
320 that GUI user modules get loaded and are broken by the setuid Exim being
321 unable to access files specified in environment variables and passed
322 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
323 unless this new option is set.
325 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
326 so have also added a build option which can be used to build Exim with GnuTLS
327 but without trying to use any kind of PKCS11 support. Uncomment this in the
330 AVOID_GNUTLS_PKCS11=yes
332 10. The "acl = name" condition on an ACL now supports optional arguments.
333 New expansion item "${acl {name}{arg}...}" and expansion condition
334 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
335 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
336 Variable $acl_narg contains the number of arguments. If the ACL sets
337 a "message =" value this becomes the result of the expansion item,
338 or the value of $value for the expansion condition. If the ACL returns
339 accept the expansion condition is true; if reject, false. A defer
340 return results in a forced fail.
342 11. Routers and transports can now have multiple headers_add and headers_remove
343 option lines. The concatenated list is used.
345 12. New ACL modifier "remove_header" can remove headers before message gets
346 handled by routers/transports.
348 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
349 "aaaa" and "a" lookups is done and the full set of results returned.
351 14. New expansion variable $headers_added with content from ACL add_header
352 modifier (but not yet added to message).
354 15. New 8bitmime status logging option for received messages. Log field "M8S".
356 16. New authenticated_sender logging option, adding to log field "A".
358 17. New expansion variables $router_name and $transport_name. Useful
359 particularly for debug_print as -bt command-line option does not
360 require privilege whereas -d does.
362 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
363 proposed extension to SMTP from Eric Hall.
365 19. The pipe transport has gained the force_command option, to allow
366 decorating commands from user .forward pipe aliases with prefix
367 wrappers, for instance.
369 20. Callout connections can now AUTH; the same controls as normal delivery
372 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
373 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
374 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
375 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
376 dmarc_status. It adds new control flags dmarc_disable_verify and
377 dmarc_enable_forensic.
379 22. Add expansion variable $authenticated_fail_id, which is the username
380 provided to the authentication method which failed. It is available
381 for use in subsequent ACL processing (typically quit or notquit ACLs).
383 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
386 24. New ${hexquote:..string..} expansion operator converts non-printable
387 characters in the string to \xNN form.
389 25. Experimental TPDA (Transport Post Delivery Action) function added.
390 Patch provided by Axel Rau.
392 26. Experimental Redis lookup added. Patch provided by Warren Baker.
398 1. New authenticator driver, "gsasl". Server-only (at present).
399 This is a SASL interface, licensed under GPL, which can be found at
400 http://www.gnu.org/software/gsasl/.
401 This system does not provide sources of data for authentication, so
402 careful use needs to be made of the conditions in Exim.
404 2. New authenticator driver, "heimdal_gssapi". Server-only.
405 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
406 is no longer honoured for setuid programs by Heimdal. Use the
407 "server_keytab" option to point to the keytab.
409 3. The "pkg-config" system can now be used when building Exim to reference
410 cflags and library information for lookups and authenticators, rather
411 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
412 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
413 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
415 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
416 find the headers and libraries for PCRE.
418 4. New expansion variable $tls_bits.
420 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
421 be joined together with ASCII NUL characters to construct the key to pass
422 into the DBM library. Can be used with gsasl to access sasldb2 files as
425 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
427 Avoid release 1.0.1a if you can. Note that the default value of
428 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
429 increased susceptibility to attack. This may still have interoperability
430 implications for very old clients (see version 4.31 change 37) but
431 administrators can choose to make the trade-off themselves and restore
432 compatibility at the cost of session security.
434 7. Use of the new expansion variable $tls_sni in the main configuration option
435 tls_certificate will cause Exim to re-expand the option, if the client
436 sends the TLS Server Name Indication extension, to permit choosing a
437 different certificate; tls_privatekey will also be re-expanded. You must
438 still set these options to expand to valid files when $tls_sni is not set.
440 The SMTP Transport has gained the option tls_sni, which will set a hostname
441 for outbound TLS sessions, and set $tls_sni too.
443 A new log_selector, +tls_sni, has been added, to log received SNI values
444 for Exim as a server.
446 8. The existing "accept_8bitmime" option now defaults to true. This means
447 that Exim is deliberately not strictly RFC compliant. We're following
448 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
449 Those who disagree, or know that they are talking to mail servers that,
450 even today, are not 8-bit clean, need to turn off this option.
452 9. Exim can now be started with -bw (with an optional timeout, given as
453 -bw<timespec>). With this, stdin at startup is a socket that is
454 already listening for connections. This has a more modern name of
455 "socket activation", but forcing the activated socket to fd 0. We're
456 interested in adding more support for modern variants.
458 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
459 for numbers indicates multiplication by 1024^3.
461 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
462 gnutls_require_mac & gnutls_require_protocols are no longer supported.
463 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
464 string, documentation for which is at:
465 http://www.gnutls.org/manual/html_node/Priority-Strings.html
467 SNI support has been added to Exim's GnuTLS integration too.
469 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
470 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
472 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
473 is now available. If the contents of the file are valid, then Exim will
474 send that back in response to a TLS status request; this is OCSP Stapling.
475 Exim will not maintain the contents of the file in any way: administrators
476 are responsible for ensuring that it is up-to-date.
478 See "experimental-spec.txt" for more details.
480 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
481 identically to TXT record lookups.
483 14. New expansion variable $tod_epoch_l for higher-precision time.
485 15. New global option tls_dh_max_bits, defaulting to current value of NSS
486 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
487 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
489 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
490 Option can now be a path or an identifier for a standard prime.
491 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
492 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
495 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
496 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
497 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
503 1. New options for the ratelimit ACL condition: /count= and /unique=.
504 The /noupdate option has been replaced by a /readonly option.
506 2. The SMTP transport's protocol option may now be set to "smtps", to
507 use SSL-on-connect outbound.
509 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
510 there is a problem talking to the AV scanner, or the AV scanner running.
512 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
513 and check if the search item is a member of the list. This does not
514 support named lists, but does subject the list part to string expansion.
516 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
517 built, Exim no longer performs string expansion on the second string of
518 the match_* expansion conditions: "match_address", "match_domain",
519 "match_ip" & "match_local_part". Named lists can still be used.
525 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
526 or off in the resolver library.
532 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
533 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
534 libraries. The following global options have been added in support of
535 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
536 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
538 2. The pipe transport now takes a boolean option, "freeze_signal", default
539 false. When true, if the external delivery command exits on a signal then
540 Exim will freeze the message in the queue, instead of generating a bounce.
542 3. Log filenames may now use %M as an escape, instead of %D (still available).
543 The %M pattern expands to yyyymm, providing month-level resolution.
545 4. The $message_linecount variable is now updated for the maildir_tag option,
546 in the same way as $message_size, to reflect the real number of lines,
547 including any header additions or removals from transport.
549 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
550 Exim now selects entries randomly, to better scale in a cluster setup.
556 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
557 the flaw permitted the Exim run-time user to cause root to append to
558 arbitrary files of the attacker's choosing, with the content based
559 on content supplied by the attacker.
561 2. Exim now supports loading some lookup types at run-time, using your
562 platform's dlopen() functionality. This has limited platform support
563 and the intention is not to support every variant, it's limited to
564 dlopen(). This permits the main Exim binary to not be linked against
565 all the libraries needed for all the lookup types.
571 NOTE: this version is not guaranteed backwards-compatible, please read the
572 items below carefully
574 1. A new main configuration option, "openssl_options", is available if Exim
575 is built with SSL support provided by OpenSSL. The option allows
576 administrators to specify OpenSSL options to be used on connections;
577 typically this is to set bug compatibility features which the OpenSSL
578 developers have not enabled by default. There may be security
579 consequences for certain options, so these should not be changed
582 2. A new pipe transport option, "permit_coredumps", may help with problem
583 diagnosis in some scenarios. Note that Exim is typically installed as
584 a setuid binary, which on most OSes will inhibit coredumps by default,
585 so that safety mechanism would have to be overridden for this option to
586 be able to take effect.
588 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
589 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
590 Note that this switches Exim to use a new API ("INSTREAM") and a future
591 release of ClamAV will remove support for the old API ("STREAM").
593 The av_scanner option, when set to "clamd", now takes an optional third
594 part, "local", which causes Exim to pass a filename to ClamAV instead of
595 the file content. This is the same behaviour as when clamd is pointed at
596 a Unix-domain socket. For example:
598 av_scanner = clamd:192.0.2.3 1234:local
600 ClamAV's ExtendedDetectionInfo response format is now handled.
602 4. There is now a -bmalware option, restricted to admin users. This option
603 takes one parameter, a filename, and scans that file with Exim's
604 malware-scanning framework. This is intended purely as a debugging aid
605 to ensure that Exim's scanning is working, not to replace other tools.
606 Note that the ACL framework is not invoked, so if av_scanner references
607 ACL variables without a fallback then this will fail.
609 5. There is a new expansion operator, "reverse_ip", which will reverse IP
610 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
612 ${reverse_ip:192.0.2.4}
614 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
615 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
617 6. There is a new ACL control called "debug", to enable debug logging.
618 This allows selective logging of certain incoming transactions within
619 production environments, with some care. It takes two options, "tag"
620 and "opts"; "tag" is included in the filename of the log and "opts"
621 is used as per the -d<options> command-line option. Examples, which
622 don't all make sense in all contexts:
625 control = debug/tag=.$sender_host_address
626 control = debug/opts=+expand+acl
627 control = debug/tag=.$message_exim_id/opts=+expand
629 7. It has always been implicit in the design and the documentation that
630 "the Exim user" is not root. src/EDITME said that using root was
631 "very strongly discouraged". This is not enough to keep people from
632 shooting themselves in the foot in days when many don't configure Exim
633 themselves but via package build managers. The security consequences of
634 running various bits of network code are severe if there should be bugs in
635 them. As such, the Exim user may no longer be root. If configured
636 statically, Exim will refuse to build. If configured as ref:user then Exim
637 will exit shortly after start-up. If you must shoot yourself in the foot,
638 then henceforth you will have to maintain your own local patches to strip
641 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
642 condition logic to determine truth/failure and will fail to expand many
643 strings, bool_lax{} uses the router condition logic, where most strings
645 Note: bool{00} is false, bool_lax{00} is true.
647 9. Routers now support multiple "condition" tests.
649 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
650 Setting this allows an admin to define which entry in the tcpwrappers
651 config file will be used to control access to the daemon. This option
652 is only available when Exim is built with USE_TCP_WRAPPERS. The
653 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
656 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
657 the Exim run-time user, instead of root.
659 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
660 is forced on. This is mitigated by the new build option
661 TRUSTED_CONFIG_LIST which defines a list of configuration files which
662 are trusted; one per line. If a config file is owned by root and matches
663 a pathname in the list, then it may be invoked by the Exim build-time
664 user without Exim relinquishing root privileges.
666 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
667 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
668 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
669 include the main config. As a transition mechanism, we are temporarily
670 providing a work-around: the new build option WHITELIST_D_MACROS provides
671 a colon-separated list of macro names which may be overridden by the Exim
672 run-time user. The values of these macros are constrained to the regex
673 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
679 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
680 writable, the other to locking of MBX folders (not mbox).
682 2. MySQL stored procedures are now supported.
684 3. The dkim_domain transport option is now a list, not a single string, and
685 messages will be signed for each element in the list (discarding
688 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
689 in the presence of multiple character strings within the RR. Prior to 4.70,
690 only the first string would be returned. The dnsdb lookup now, by default,
691 preserves the pre-4.70 semantics, but also now takes an extended output
692 separator specification. The separator can be followed by a semicolon, to
693 concatenate the individual text strings together with no join character,
694 or by a comma and a second separator character, in which case the text
695 strings within a TXT record are joined on that second character.
696 Administrators are reminded that DNS provides no ordering guarantees
697 between multiple records in an RRset. For example:
699 foo.example. IN TXT "a" "b" "c"
700 foo.example. IN TXT "d" "e" "f"
702 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
703 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
704 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
710 1. Native DKIM support without an external library.
711 (Note that if no action to prevent it is taken, a straight upgrade will
712 result in DKIM verification of all signed incoming emails. See spec
713 for details on conditionally disabling)
715 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
717 3. There is now a bool{} expansion condition which maps certain strings to
718 true/false condition values (most likely of use in conjunction with the
719 and{} expansion operator).
721 4. The $spam_score, $spam_bar and $spam_report variables are now available
724 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
725 options, provided that Exim is invoked by an admin_user.
727 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
728 which increases compatibility with older clients at the cost of decreased
729 security. Don't set this unless you need to support such clients.
731 7. There is a new expansion operator, ${randint:...} which will produce a
732 "random" number less than the supplied integer. This randomness is
733 not guaranteed to be cryptographically strong, but depending upon how
734 Exim was built may be better than the most naive schemes.
736 8. Exim now explicitly ensures that SHA256 is available when linked against
739 9. The transport_filter_timeout option now applies to SMTP transports too.
745 1. Preliminary DKIM support in Experimental.
751 1. The body_linecount and body_zerocount C variables are now exported in the
754 2. When a dnslists lookup succeeds, the key that was looked up is now placed
755 in $dnslist_matched. When the key is an IP address, it is not reversed in
756 this variable (though it is, of course, in the actual lookup). In simple
759 deny dnslists = spamhaus.example
761 the key is also available in another variable (in this case,
762 $sender_host_address). In more complicated cases, however, this is not
763 true. For example, using a data lookup might generate a dnslists lookup
766 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
768 If this condition succeeds, the value in $dnslist_matched might be
769 192.168.6.7 (for example).
771 3. Authenticators now have a client_condition option. When Exim is running as
772 a client, it skips an authenticator whose client_condition expansion yields
773 "0", "no", or "false". This can be used, for example, to skip plain text
774 authenticators when the connection is not encrypted by a setting such as:
776 client_condition = ${if !eq{$tls_cipher}{}}
778 Note that the 4.67 documentation states that $tls_cipher contains the
779 cipher used for incoming messages. In fact, during SMTP delivery, it
780 contains the cipher used for the delivery. The same is true for
783 4. There is now a -Mvc <message-id> option, which outputs a copy of the
784 message to the standard output, in RFC 2822 format. The option can be used
785 only by an admin user.
787 5. There is now a /noupdate option for the ratelimit ACL condition. It
788 computes the rate and checks the limit as normal, but it does not update
789 the saved data. This means that, in relevant ACLs, it is possible to lookup
790 the existence of a specified (or auto-generated) ratelimit key without
791 incrementing the ratelimit counter for that key.
793 In order for this to be useful, another ACL entry must set the rate
794 for the same key somewhere (otherwise it will always be zero).
799 # Read the rate; if it doesn't exist or is below the maximum
801 deny ratelimit = 100 / 5m / strict / noupdate
802 log_message = RATE: $sender_rate / $sender_rate_period \
803 (max $sender_rate_limit)
805 [... some other logic and tests...]
807 warn ratelimit = 100 / 5m / strict / per_cmd
808 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
809 (max $sender_rate_limit)
810 condition = ${if le{$sender_rate}{$sender_rate_limit}}
814 6. The variable $max_received_linelength contains the number of bytes in the
815 longest line that was received as part of the message, not counting the
816 line termination character(s).
818 7. Host lists can now include +ignore_defer and +include_defer, analagous to
819 +ignore_unknown and +include_unknown. These options should be used with
820 care, probably only in non-critical host lists such as whitelists.
822 8. There's a new option called queue_only_load_latch, which defaults true.
823 If set false when queue_only_load is greater than zero, Exim re-evaluates
824 the load for each incoming message in an SMTP session. Otherwise, once one
825 message is queued, the remainder are also.
827 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
828 cases when an SMTP session ends without sending QUIT. However, when Exim
829 itself is is bad trouble, such as being unable to write to its log files,
830 this ACL is not run, because it might try to do things (such as write to
831 log files) that make the situation even worse.
833 Like the QUIT ACL, this new ACL is provided to make it possible to gather
834 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
835 modifier is forbidden in this ACL.
837 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
838 to a string that indicates the reason for the termination of the SMTP
839 connection. The possible values are:
841 acl-drop Another ACL issued a "drop" command
842 bad-commands Too many unknown or non-mail commands
843 command-timeout Timeout while reading SMTP commands
844 connection-lost The SMTP connection has been lost
845 data-timeout Timeout while reading message data
846 local-scan-error The local_scan() function crashed
847 local-scan-timeout The local_scan() function timed out
848 signal-exit SIGTERM or SIGINT
849 synchronization-error SMTP synchronization error
850 tls-failed TLS failed to start
852 In most cases when an SMTP connection is closed without having received
853 QUIT, Exim sends an SMTP response message before actually closing the
854 connection. With the exception of acl-drop, the default message can be
855 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
856 "drop" verb in another ACL, it is the message from the other ACL that is
859 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
860 servers with individual queries. This is done by starting the query with
861 "servers=x:y:z;", where each item in the list may take one of two forms:
863 (1) If it is just a host name, the appropriate global option (mysql_servers
864 or pgsql_servers) is searched for a host of the same name, and the
865 remaining parameters (database, user, password) are taken from there.
867 (2) If it contains any slashes, it is taken as a complete parameter set.
869 The list of servers is used in exactly the same was as the global list.
870 Once a connection to a server has happened and a query has been
871 successfully executed, processing of the lookup ceases.
873 This feature is intended for use in master/slave situations where updates
874 are occurring, and one wants to update a master rather than a slave. If the
875 masters are in the list for reading, you might have:
877 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
879 In an updating lookup, you could then write
881 ${lookup mysql{servers=master; UPDATE ...}
883 If, on the other hand, the master is not to be used for reading lookups:
885 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
887 you can still update the master by
889 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
891 11. The message_body_newlines option (default FALSE, for backwards
892 compatibility) can be used to control whether newlines are present in
893 $message_body and $message_body_end. If it is FALSE, they are replaced by
900 1. There is a new log selector called smtp_no_mail, which is not included in
901 the default setting. When it is set, a line is written to the main log
902 whenever an accepted SMTP connection terminates without having issued a
905 2. When an item in a dnslists list is followed by = and & and a list of IP
906 addresses, the behaviour was not clear when the lookup returned more than
907 one IP address. This has been solved by the addition of == and =& for "all"
908 rather than the default "any" matching.
910 3. Up till now, the only control over which cipher suites GnuTLS uses has been
911 for the cipher algorithms. New options have been added to allow some of the
912 other parameters to be varied.
914 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
915 set, Exim compiles a runtime option called disable_fsync.
917 5. There is a new variable called $smtp_count_at_connection_start.
919 6. There's a new control called no_pipelining.
921 7. There are two new variables called $sending_ip_address and $sending_port.
922 These are set whenever an SMTP connection to another host has been set up.
924 8. The expansion of the helo_data option in the smtp transport now happens
925 after the connection to the server has been made.
927 9. There is a new expansion operator ${rfc2047d: that decodes strings that
928 are encoded as per RFC 2047.
930 10. There is a new log selector called "pid", which causes the current process
931 id to be added to every log line, in square brackets, immediately after the
934 11. Exim has been modified so that it flushes SMTP output before implementing
935 a delay in an ACL. It also flushes the output before performing a callout,
936 as this can take a substantial time. These behaviours can be disabled by
937 obeying control = no_delay_flush or control = no_callout_flush,
938 respectively, at some earlier stage of the connection.
940 12. There are two new expansion conditions that iterate over a list. They are
941 called forany and forall.
943 13. There's a new global option called dsn_from that can be used to vary the
944 contents of From: lines in bounces and other automatically generated
945 messages ("delivery status notifications" - hence the name of the option).
947 14. The smtp transport has a new option called hosts_avoid_pipelining.
949 15. By default, exigrep does case-insensitive matches. There is now a -I option
950 that makes it case-sensitive.
952 16. A number of new features ("addresses", "map", "filter", and "reduce") have
953 been added to string expansions to make it easier to process lists of
954 items, typically addresses.
956 17. There's a new ACL modifier called "continue". It does nothing of itself,
957 and processing of the ACL always continues with the next condition or
958 modifier. It is provided so that the side effects of expanding its argument
961 18. It is now possible to use newline and other control characters (those with
962 values less than 32, plus DEL) as separators in lists.
964 19. The exigrep utility now has a -v option, which inverts the matching
967 20. The host_find_failed option in the manualroute router can now be set to
974 No new features were added to 4.66.
980 No new features were added to 4.65.
986 1. ACL variables can now be given arbitrary names, as long as they start with
987 "acl_c" or "acl_m" (for connection variables and message variables), are at
988 least six characters long, with the sixth character being either a digit or
991 2. There is a new ACL modifier called log_reject_target. It makes it possible
992 to specify which logs are used for messages about ACL rejections.
994 3. There is a new authenticator called "dovecot". This is an interface to the
995 authentication facility of the Dovecot POP/IMAP server, which can support a
996 number of authentication methods.
998 4. The variable $message_headers_raw provides a concatenation of all the
999 messages's headers without any decoding. This is in contrast to
1000 $message_headers, which does RFC2047 decoding on the header contents.
1002 5. In a DNS black list, if two domain names, comma-separated, are given, the
1003 second is used first to do an initial check, making use of any IP value
1004 restrictions that are set. If there is a match, the first domain is used,
1005 without any IP value restrictions, to get the TXT record.
1007 6. All authenticators now have a server_condition option.
1009 7. There is a new command-line option called -Mset. It is useful only in
1010 conjunction with -be (that is, when testing string expansions). It must be
1011 followed by a message id; Exim loads the given message from its spool
1012 before doing the expansions.
1014 8. Another similar new command-line option is called -bem. It operates like
1015 -be except that it must be followed by the name of a file that contains a
1018 9. When an address is delayed because of a 4xx response to a RCPT command, it
1019 is now the combination of sender and recipient that is delayed in
1020 subsequent queue runs until its retry time is reached.
1022 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1023 shift, have been added to the eval: and eval10: expansion items.
1025 11. The variables $interface_address and $interface_port have been renamed
1026 as $received_ip_address and $received_port, to make it clear that they
1027 relate to message reception rather than delivery. (The old names remain
1028 available for compatibility.)
1030 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1031 to vary the message that is sent when an SMTP command is accepted.
1037 1. There is a new Boolean option called filter_prepend_home for the redirect
1040 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1041 start of receiving a non-SMTP message, before any of the message has been
1044 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1045 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1046 start of the message for an SMTP error code.
1048 4. There is a new parameter for LDAP lookups called "referrals", which takes
1049 one of the settings "follow" (the default) or "nofollow".
1051 5. Version 20070721.2 of exipick now included, offering these new options:
1053 After all other sorting options have bee processed, reverse order
1054 before displaying messages (-R is synonym).
1056 Randomize order of matching messages before displaying.
1058 Instead of displaying the matching messages, display the sum
1060 --sort <variable>[,<variable>...]
1061 Before displaying matching messages, sort the messages according to
1062 each messages value for each variable.
1064 Negate the value for every test (returns inverse output from the
1065 same criteria without --not).
1071 1. The ${readsocket expansion item now supports Internet domain sockets as well
1072 as Unix domain sockets. If the first argument begins "inet:", it must be of
1073 the form "inet:host:port". The port is mandatory; it may be a number or the
1074 name of a TCP port in /etc/services. The host may be a name, or it may be an
1075 IP address. An ip address may optionally be enclosed in square brackets.
1076 This is best for IPv6 addresses. For example:
1078 ${readsocket{inet:[::1]:1234}{<request data>}...
1080 Only a single host name may be given, but if looking it up yield more than
1081 one IP address, they are each tried in turn until a connection is made. Once
1082 a connection has been made, the behaviour is as for ${readsocket with a Unix
1085 2. If a redirect router sets up file or pipe deliveries for more than one
1086 incoming address, and the relevant transport has batch_max set greater than
1087 one, a batch delivery now occurs.
1089 3. The appendfile transport has a new option called maildirfolder_create_regex.
1090 Its value is a regular expression. For a maildir delivery, this is matched
1091 against the maildir directory; if it matches, Exim ensures that a
1092 maildirfolder file is created alongside the new, cur, and tmp directories.
1098 The documentation is up-to-date for the 4.61 release. Major new features since
1099 the 4.60 release are:
1101 . An option called disable_ipv6, to disable the use of IPv6 completely.
1103 . An increase in the number of ACL variables to 20 of each type.
1105 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1106 $2, $3, (though those are still set) because the numeric variables get used
1107 for other things in complicated expansions.
1109 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1111 . It is possible to use setclassresources() on some BSD OS to control the
1112 resources used in pipe deliveries.
1114 . A new ACL modifier called add_header, which can be used with any verb.
1116 . More errors are detectable in retry rules.
1118 There are a number of other additions too.
1124 The documentation is up-to-date for the 4.60 release. Major new features since
1125 the 4.50 release are:
1127 . Support for SQLite.
1129 . Support for IGNOREQUOTA in LMTP.
1131 . Extensions to the "submission mode" features.
1133 . Support for Client SMTP Authorization (CSA).
1135 . Support for ratelimiting hosts and users.
1137 . New expansion items to help with the BATV "prvs" scheme.
1139 . A "match_ip" condition, that matches an IP address against a list.
1141 There are many more minor changes.
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