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.
19 1. Allow relative config file names for ".include"
21 2. A main-section config option "debug_store" to control the checks on
22 variable locations during store-reset. Normally false but can be enabled
23 when a memory corrution issue is suspected on a production system.
29 1. The new perl_taintmode option allows to run the embedded perl
30 interpreter in taint mode.
32 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
34 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
37 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
38 N can be 224, 256 (default), 384, 512.
39 With GnuTLS 3.5.0 or later, only.
41 5. Facility for named queues: A command-line argument can specify
42 the queue name for a queue operation, and an ACL modifier can set
43 the queue to be used for a message. A $queue_name variable gives
46 6. New expansion operators base32/base32d.
48 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
49 performance increase and network load decrease. Main config option
50 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
53 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
55 9. Expansion operator escape8bit, like escape but not touching newline etc..
57 10. Feature macros, generated from compile options. All start with "_HAVE_"
58 and go on with some roughly recognisable name. Driver macros, for
59 router, transport and authentication drivers; names starting with "_DRIVER_".
60 Option macros, for each configuration-file option; all start with "_OPT_".
61 Use the "-bP macros" command-line option to see what is present.
63 11. Integer values for options can take a "G" multiplier.
65 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
66 returns from the target back to the initiator, rather than spooling the
69 13. New built-in constants available for tls_dhparam and default changed.
71 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
72 out copies of the message spool files for use by 3rd-party scanners.
74 15. A new option on the smtp transport, hosts_try_fastopen. If the system
75 supports it (on Linux it must be enabled in the kernel by the sysadmin)
76 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
77 but it permits a peer that also supports the facility to send its SMTP
78 banner immediately after the SYN,ACK segment rather then waiting for
79 another ACK - so saving up to one roundtrip time. Because it requires
80 previous communication with the peer (we save a cookie from it) this
81 will only become active on frequently-contacted destinations.
83 16. A new syslog_pid option to suppress PID duplication in syslog lines.
89 1. The ACL conditions regex and mime_regex now capture substrings
90 into numeric variables $regex1 to 9, like the "match" expansion condition.
92 2. New $callout_address variable records the address used for a spam=,
93 malware= or verify= callout.
95 3. Transports now take a "max_parallel" option, to limit concurrency.
97 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
98 The latter expands to a 8-element colon-sep set of hex digits including
99 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
100 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
101 The former operator strips leading zeroes and collapses the longest
102 set of 0-groups to a double-colon.
104 5. New "-bP config" support, to dump the effective configuration.
106 6. New $dkim_key_length variable.
108 7. New base64d and base64 expansion items (the existing str2b64 being a
109 synonym of the latter). Add support in base64 for certificates.
111 8. New main configuration option "bounce_return_linesize_limit" to
112 avoid oversize bodies in bounces. The default value matches RFC
115 9. New $initial_cwd expansion variable.
121 1. Support for using the system standard CA bundle.
123 2. New expansion items $config_file, $config_dir, containing the file
124 and directory name of the main configuration file. Also $exim_version.
126 3. New "malware=" support for Avast.
128 4. New "spam=" variant option for Rspamd.
130 5. Assorted options on malware= and spam= scanners.
132 6. A command-line option to write a comment into the logfile.
134 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
135 be configured to make connections via socks5 proxies.
137 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
138 the transmission of UTF-8 envelope addresses.
140 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
141 used encoding of Maildir folder names.
143 10. A logging option for slow DNS lookups.
145 11. New ${env {<variable>}} expansion.
147 12. A non-SMTP authenticator using information from TLS client certificates.
149 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
150 Patch originally by Wolfgang Breyha.
152 14. Main option "dns_trust_aa" for trusting your local nameserver at the
153 same level as DNSSEC.
159 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
160 DANE SMTP draft to assess a secure chain of trust of the certificate
161 used to establish the TLS connection based on a TLSA record in the
162 domain of the sender.
164 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
165 and several new events have been created. The reason is because it has
166 been expanded beyond just firing events during the transport phase. Any
167 existing TPDA transport options will have to be rewritten to use a new
168 $event_name expansion variable in a condition. Refer to the
169 experimental-spec.txt for details and examples.
171 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
172 server certs used for TLS match the result of the MX lookup. It does
173 not use the same mechanism as DANE.
183 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
184 configured to expect an initial header from a proxy that will make the
185 actual external source IP:host be used in exim instead of the IP of the
186 proxy that is connecting to it.
188 2. New verify option header_names_ascii, which will check to make sure
189 there are no non-ASCII characters in header names. Exim itself handles
190 those non-ASCII characters, but downstream apps may not, so Exim can
191 detect and reject if those characters are present.
193 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
194 codepoints with valid ones.
196 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
197 command line and matching a regex against the return data for trigger
198 and a second regex to extract malware_name. The mail spoolfile name can
199 be included in the command line.
201 5. The smtp transport now supports options "tls_verify_hosts" and
202 "tls_try_verify_hosts". If either is set the certificate verification
203 is split from the encryption operation. The default remains that a failed
204 verification cancels the encryption.
206 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
207 lookup can now set a list of servers to use that is different from the
210 7. New command-line option -C for exiqgrep to specify alternate exim.conf
211 file when searching the queue.
213 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
215 9. Support for DNSSEC on outbound connections.
217 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
218 "certextract" to extract fields from them. Hash operators md5 and sha1
219 work over them for generating fingerprints, and a new sha256 operator
222 11. PRDR is now supported dy default.
224 12. OCSP stapling is now supported by default.
226 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
227 Delivery Status Notification messages in MIME format, and negotiate
228 DSN features per RFC 3461.
234 1. New command-line option -bI:sieve will list all supported sieve extensions
235 of this Exim build on standard output, one per line.
236 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
237 query this to establish the correct list to include in the protocol's
238 SIEVE capability line.
240 2. If the -n option is combined with the -bP option, then the name of an
241 emitted option is not output, only the value (if visible to you).
242 For instance, "exim -n -bP pid_file_path" should just emit a pathname
243 followed by a newline, and no other text.
245 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
246 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
247 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
248 acceptable for security. (Option accepted but ignored if using OpenSSL).
249 Defaults to 1024, the old value. May be lowered only to 512, or raised as
250 far as you like. Raising this may hinder TLS interoperability with other
251 sites and is not currently recommended. Lowering this will permit you to
252 establish a TLS session which is not as secure as you might like.
254 Unless you really know what you are doing, leave it alone.
256 4. If not built with DISABLE_DNSSEC, Exim now has the main option
257 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
258 to send the DO flag to your recursive resolver. If you have a recursive
259 resolver, which can set the Authenticated Data (AD) flag in results, Exim
260 can now detect this. Exim does not perform validation itself, instead
261 relying upon a trusted path to the resolver.
263 Current status: work-in-progress; $sender_host_dnssec variable added.
265 5. DSCP support for outbound connections: on a transport using the smtp driver,
266 set "dscp = ef", for instance, to cause the connections to have the relevant
267 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
269 Similarly for inbound connections, there is a new control modifier, dscp,
270 so "warn control = dscp/ef" in the connect ACL, or after authentication.
272 Supported values depend upon system libraries. "exim -bI:dscp" to list the
273 ones Exim knows of. You can also set a raw number 0..0x3F.
275 6. The -G command-line flag is no longer ignored; it is now equivalent to an
276 ACL setting "control = suppress_local_fixups". The -L command-line flag
277 is now accepted and forces use of syslog, with the provided tag as the
278 process name. A few other flags used by Sendmail are now accepted and
281 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
282 ACL modifier; works for single-recipient mails which are received on and
283 deliverable via SMTP. Using the connection made for a recipient verify,
284 if requested before the verify, or a new one made for the purpose while
285 the inbound connection is still active. The bulk of the mail item is copied
286 direct from the inbound socket to the outbound (as well as the spool file).
287 When the source notifies the end of data, the data acceptance by the destination
288 is negotiated before the acceptance is sent to the source. If the destination
289 does not accept the mail item, for example due to content-scanning, the item
290 is not accepted from the source and therefore there is no need to generate
291 a bounce mail. This is of benefit when providing a secondary-MX service.
292 The downside is that delays are under the control of the ultimate destination
295 The Received-by: header on items delivered by cutthrough is generated
296 early in reception rather than at the end; this will affect any timestamp
297 included. The log line showing delivery is recorded before that showing
298 reception; it uses a new ">>" tag instead of "=>".
300 To support the feature, verify-callout connections can now use ESMTP and TLS.
301 The usual smtp transport options are honoured, plus a (new, default everything)
302 hosts_verify_avoid_tls.
304 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
305 for specific access to the information for each connection. The old names
306 are present for now but deprecated.
308 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
310 8. New expansion operators ${listnamed:name} to get the content of a named list
311 and ${listcount:string} to count the items in a list.
313 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
314 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
315 modules. For some situations this is desirable, but we expect admin in
316 those situations to know they want the feature. More commonly, it means
317 that GUI user modules get loaded and are broken by the setuid Exim being
318 unable to access files specified in environment variables and passed
319 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
320 unless this new option is set.
322 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
323 so have also added a build option which can be used to build Exim with GnuTLS
324 but without trying to use any kind of PKCS11 support. Uncomment this in the
327 AVOID_GNUTLS_PKCS11=yes
329 10. The "acl = name" condition on an ACL now supports optional arguments.
330 New expansion item "${acl {name}{arg}...}" and expansion condition
331 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
332 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
333 Variable $acl_narg contains the number of arguments. If the ACL sets
334 a "message =" value this becomes the result of the expansion item,
335 or the value of $value for the expansion condition. If the ACL returns
336 accept the expansion condition is true; if reject, false. A defer
337 return results in a forced fail.
339 11. Routers and transports can now have multiple headers_add and headers_remove
340 option lines. The concatenated list is used.
342 12. New ACL modifier "remove_header" can remove headers before message gets
343 handled by routers/transports.
345 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
346 "aaaa" and "a" lookups is done and the full set of results returned.
348 14. New expansion variable $headers_added with content from ACL add_header
349 modifier (but not yet added to message).
351 15. New 8bitmime status logging option for received messages. Log field "M8S".
353 16. New authenticated_sender logging option, adding to log field "A".
355 17. New expansion variables $router_name and $transport_name. Useful
356 particularly for debug_print as -bt command-line option does not
357 require privilege whereas -d does.
359 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
360 proposed extension to SMTP from Eric Hall.
362 19. The pipe transport has gained the force_command option, to allow
363 decorating commands from user .forward pipe aliases with prefix
364 wrappers, for instance.
366 20. Callout connections can now AUTH; the same controls as normal delivery
369 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
370 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
371 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
372 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
373 dmarc_status. It adds new control flags dmarc_disable_verify and
374 dmarc_enable_forensic.
376 22. Add expansion variable $authenticated_fail_id, which is the username
377 provided to the authentication method which failed. It is available
378 for use in subsequent ACL processing (typically quit or notquit ACLs).
380 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
383 24. New ${hexquote:..string..} expansion operator converts non-printable
384 characters in the string to \xNN form.
386 25. Experimental TPDA (Transport Post Delivery Action) function added.
387 Patch provided by Axel Rau.
389 26. Experimental Redis lookup added. Patch provided by Warren Baker.
395 1. New authenticator driver, "gsasl". Server-only (at present).
396 This is a SASL interface, licensed under GPL, which can be found at
397 http://www.gnu.org/software/gsasl/.
398 This system does not provide sources of data for authentication, so
399 careful use needs to be made of the conditions in Exim.
401 2. New authenticator driver, "heimdal_gssapi". Server-only.
402 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
403 is no longer honoured for setuid programs by Heimdal. Use the
404 "server_keytab" option to point to the keytab.
406 3. The "pkg-config" system can now be used when building Exim to reference
407 cflags and library information for lookups and authenticators, rather
408 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
409 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
410 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
412 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
413 find the headers and libraries for PCRE.
415 4. New expansion variable $tls_bits.
417 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
418 be joined together with ASCII NUL characters to construct the key to pass
419 into the DBM library. Can be used with gsasl to access sasldb2 files as
422 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
424 Avoid release 1.0.1a if you can. Note that the default value of
425 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
426 increased susceptibility to attack. This may still have interoperability
427 implications for very old clients (see version 4.31 change 37) but
428 administrators can choose to make the trade-off themselves and restore
429 compatibility at the cost of session security.
431 7. Use of the new expansion variable $tls_sni in the main configuration option
432 tls_certificate will cause Exim to re-expand the option, if the client
433 sends the TLS Server Name Indication extension, to permit choosing a
434 different certificate; tls_privatekey will also be re-expanded. You must
435 still set these options to expand to valid files when $tls_sni is not set.
437 The SMTP Transport has gained the option tls_sni, which will set a hostname
438 for outbound TLS sessions, and set $tls_sni too.
440 A new log_selector, +tls_sni, has been added, to log received SNI values
441 for Exim as a server.
443 8. The existing "accept_8bitmime" option now defaults to true. This means
444 that Exim is deliberately not strictly RFC compliant. We're following
445 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
446 Those who disagree, or know that they are talking to mail servers that,
447 even today, are not 8-bit clean, need to turn off this option.
449 9. Exim can now be started with -bw (with an optional timeout, given as
450 -bw<timespec>). With this, stdin at startup is a socket that is
451 already listening for connections. This has a more modern name of
452 "socket activation", but forcing the activated socket to fd 0. We're
453 interested in adding more support for modern variants.
455 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
456 for numbers indicates multiplication by 1024^3.
458 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
459 gnutls_require_mac & gnutls_require_protocols are no longer supported.
460 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
461 string, documentation for which is at:
462 http://www.gnutls.org/manual/html_node/Priority-Strings.html
464 SNI support has been added to Exim's GnuTLS integration too.
466 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
467 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
469 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
470 is now available. If the contents of the file are valid, then Exim will
471 send that back in response to a TLS status request; this is OCSP Stapling.
472 Exim will not maintain the contents of the file in any way: administrators
473 are responsible for ensuring that it is up-to-date.
475 See "experimental-spec.txt" for more details.
477 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
478 identically to TXT record lookups.
480 14. New expansion variable $tod_epoch_l for higher-precision time.
482 15. New global option tls_dh_max_bits, defaulting to current value of NSS
483 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
484 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
486 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
487 Option can now be a path or an identifier for a standard prime.
488 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
489 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
492 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
493 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
494 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
500 1. New options for the ratelimit ACL condition: /count= and /unique=.
501 The /noupdate option has been replaced by a /readonly option.
503 2. The SMTP transport's protocol option may now be set to "smtps", to
504 use SSL-on-connect outbound.
506 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
507 there is a problem talking to the AV scanner, or the AV scanner running.
509 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
510 and check if the search item is a member of the list. This does not
511 support named lists, but does subject the list part to string expansion.
513 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
514 built, Exim no longer performs string expansion on the second string of
515 the match_* expansion conditions: "match_address", "match_domain",
516 "match_ip" & "match_local_part". Named lists can still be used.
522 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
523 or off in the resolver library.
529 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
530 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
531 libraries. The following global options have been added in support of
532 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
533 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
535 2. The pipe transport now takes a boolean option, "freeze_signal", default
536 false. When true, if the external delivery command exits on a signal then
537 Exim will freeze the message in the queue, instead of generating a bounce.
539 3. Log filenames may now use %M as an escape, instead of %D (still available).
540 The %M pattern expands to yyyymm, providing month-level resolution.
542 4. The $message_linecount variable is now updated for the maildir_tag option,
543 in the same way as $message_size, to reflect the real number of lines,
544 including any header additions or removals from transport.
546 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
547 Exim now selects entries randomly, to better scale in a cluster setup.
553 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
554 the flaw permitted the Exim run-time user to cause root to append to
555 arbitrary files of the attacker's choosing, with the content based
556 on content supplied by the attacker.
558 2. Exim now supports loading some lookup types at run-time, using your
559 platform's dlopen() functionality. This has limited platform support
560 and the intention is not to support every variant, it's limited to
561 dlopen(). This permits the main Exim binary to not be linked against
562 all the libraries needed for all the lookup types.
568 NOTE: this version is not guaranteed backwards-compatible, please read the
569 items below carefully
571 1. A new main configuration option, "openssl_options", is available if Exim
572 is built with SSL support provided by OpenSSL. The option allows
573 administrators to specify OpenSSL options to be used on connections;
574 typically this is to set bug compatibility features which the OpenSSL
575 developers have not enabled by default. There may be security
576 consequences for certain options, so these should not be changed
579 2. A new pipe transport option, "permit_coredumps", may help with problem
580 diagnosis in some scenarios. Note that Exim is typically installed as
581 a setuid binary, which on most OSes will inhibit coredumps by default,
582 so that safety mechanism would have to be overridden for this option to
583 be able to take effect.
585 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
586 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
587 Note that this switches Exim to use a new API ("INSTREAM") and a future
588 release of ClamAV will remove support for the old API ("STREAM").
590 The av_scanner option, when set to "clamd", now takes an optional third
591 part, "local", which causes Exim to pass a filename to ClamAV instead of
592 the file content. This is the same behaviour as when clamd is pointed at
593 a Unix-domain socket. For example:
595 av_scanner = clamd:192.0.2.3 1234:local
597 ClamAV's ExtendedDetectionInfo response format is now handled.
599 4. There is now a -bmalware option, restricted to admin users. This option
600 takes one parameter, a filename, and scans that file with Exim's
601 malware-scanning framework. This is intended purely as a debugging aid
602 to ensure that Exim's scanning is working, not to replace other tools.
603 Note that the ACL framework is not invoked, so if av_scanner references
604 ACL variables without a fallback then this will fail.
606 5. There is a new expansion operator, "reverse_ip", which will reverse IP
607 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
609 ${reverse_ip:192.0.2.4}
611 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
612 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
614 6. There is a new ACL control called "debug", to enable debug logging.
615 This allows selective logging of certain incoming transactions within
616 production environments, with some care. It takes two options, "tag"
617 and "opts"; "tag" is included in the filename of the log and "opts"
618 is used as per the -d<options> command-line option. Examples, which
619 don't all make sense in all contexts:
622 control = debug/tag=.$sender_host_address
623 control = debug/opts=+expand+acl
624 control = debug/tag=.$message_exim_id/opts=+expand
626 7. It has always been implicit in the design and the documentation that
627 "the Exim user" is not root. src/EDITME said that using root was
628 "very strongly discouraged". This is not enough to keep people from
629 shooting themselves in the foot in days when many don't configure Exim
630 themselves but via package build managers. The security consequences of
631 running various bits of network code are severe if there should be bugs in
632 them. As such, the Exim user may no longer be root. If configured
633 statically, Exim will refuse to build. If configured as ref:user then Exim
634 will exit shortly after start-up. If you must shoot yourself in the foot,
635 then henceforth you will have to maintain your own local patches to strip
638 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
639 condition logic to determine truth/failure and will fail to expand many
640 strings, bool_lax{} uses the router condition logic, where most strings
642 Note: bool{00} is false, bool_lax{00} is true.
644 9. Routers now support multiple "condition" tests.
646 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
647 Setting this allows an admin to define which entry in the tcpwrappers
648 config file will be used to control access to the daemon. This option
649 is only available when Exim is built with USE_TCP_WRAPPERS. The
650 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
653 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
654 the Exim run-time user, instead of root.
656 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
657 is forced on. This is mitigated by the new build option
658 TRUSTED_CONFIG_LIST which defines a list of configuration files which
659 are trusted; one per line. If a config file is owned by root and matches
660 a pathname in the list, then it may be invoked by the Exim build-time
661 user without Exim relinquishing root privileges.
663 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
664 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
665 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
666 include the main config. As a transition mechanism, we are temporarily
667 providing a work-around: the new build option WHITELIST_D_MACROS provides
668 a colon-separated list of macro names which may be overridden by the Exim
669 run-time user. The values of these macros are constrained to the regex
670 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
676 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
677 writable, the other to locking of MBX folders (not mbox).
679 2. MySQL stored procedures are now supported.
681 3. The dkim_domain transport option is now a list, not a single string, and
682 messages will be signed for each element in the list (discarding
685 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
686 in the presence of multiple character strings within the RR. Prior to 4.70,
687 only the first string would be returned. The dnsdb lookup now, by default,
688 preserves the pre-4.70 semantics, but also now takes an extended output
689 separator specification. The separator can be followed by a semicolon, to
690 concatenate the individual text strings together with no join character,
691 or by a comma and a second separator character, in which case the text
692 strings within a TXT record are joined on that second character.
693 Administrators are reminded that DNS provides no ordering guarantees
694 between multiple records in an RRset. For example:
696 foo.example. IN TXT "a" "b" "c"
697 foo.example. IN TXT "d" "e" "f"
699 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
700 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
701 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
707 1. Native DKIM support without an external library.
708 (Note that if no action to prevent it is taken, a straight upgrade will
709 result in DKIM verification of all signed incoming emails. See spec
710 for details on conditionally disabling)
712 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
714 3. There is now a bool{} expansion condition which maps certain strings to
715 true/false condition values (most likely of use in conjunction with the
716 and{} expansion operator).
718 4. The $spam_score, $spam_bar and $spam_report variables are now available
721 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
722 options, provided that Exim is invoked by an admin_user.
724 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
725 which increases compatibility with older clients at the cost of decreased
726 security. Don't set this unless you need to support such clients.
728 7. There is a new expansion operator, ${randint:...} which will produce a
729 "random" number less than the supplied integer. This randomness is
730 not guaranteed to be cryptographically strong, but depending upon how
731 Exim was built may be better than the most naive schemes.
733 8. Exim now explicitly ensures that SHA256 is available when linked against
736 9. The transport_filter_timeout option now applies to SMTP transports too.
742 1. Preliminary DKIM support in Experimental.
748 1. The body_linecount and body_zerocount C variables are now exported in the
751 2. When a dnslists lookup succeeds, the key that was looked up is now placed
752 in $dnslist_matched. When the key is an IP address, it is not reversed in
753 this variable (though it is, of course, in the actual lookup). In simple
756 deny dnslists = spamhaus.example
758 the key is also available in another variable (in this case,
759 $sender_host_address). In more complicated cases, however, this is not
760 true. For example, using a data lookup might generate a dnslists lookup
763 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
765 If this condition succeeds, the value in $dnslist_matched might be
766 192.168.6.7 (for example).
768 3. Authenticators now have a client_condition option. When Exim is running as
769 a client, it skips an authenticator whose client_condition expansion yields
770 "0", "no", or "false". This can be used, for example, to skip plain text
771 authenticators when the connection is not encrypted by a setting such as:
773 client_condition = ${if !eq{$tls_cipher}{}}
775 Note that the 4.67 documentation states that $tls_cipher contains the
776 cipher used for incoming messages. In fact, during SMTP delivery, it
777 contains the cipher used for the delivery. The same is true for
780 4. There is now a -Mvc <message-id> option, which outputs a copy of the
781 message to the standard output, in RFC 2822 format. The option can be used
782 only by an admin user.
784 5. There is now a /noupdate option for the ratelimit ACL condition. It
785 computes the rate and checks the limit as normal, but it does not update
786 the saved data. This means that, in relevant ACLs, it is possible to lookup
787 the existence of a specified (or auto-generated) ratelimit key without
788 incrementing the ratelimit counter for that key.
790 In order for this to be useful, another ACL entry must set the rate
791 for the same key somewhere (otherwise it will always be zero).
796 # Read the rate; if it doesn't exist or is below the maximum
798 deny ratelimit = 100 / 5m / strict / noupdate
799 log_message = RATE: $sender_rate / $sender_rate_period \
800 (max $sender_rate_limit)
802 [... some other logic and tests...]
804 warn ratelimit = 100 / 5m / strict / per_cmd
805 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
806 (max $sender_rate_limit)
807 condition = ${if le{$sender_rate}{$sender_rate_limit}}
811 6. The variable $max_received_linelength contains the number of bytes in the
812 longest line that was received as part of the message, not counting the
813 line termination character(s).
815 7. Host lists can now include +ignore_defer and +include_defer, analagous to
816 +ignore_unknown and +include_unknown. These options should be used with
817 care, probably only in non-critical host lists such as whitelists.
819 8. There's a new option called queue_only_load_latch, which defaults true.
820 If set false when queue_only_load is greater than zero, Exim re-evaluates
821 the load for each incoming message in an SMTP session. Otherwise, once one
822 message is queued, the remainder are also.
824 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
825 cases when an SMTP session ends without sending QUIT. However, when Exim
826 itself is is bad trouble, such as being unable to write to its log files,
827 this ACL is not run, because it might try to do things (such as write to
828 log files) that make the situation even worse.
830 Like the QUIT ACL, this new ACL is provided to make it possible to gather
831 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
832 modifier is forbidden in this ACL.
834 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
835 to a string that indicates the reason for the termination of the SMTP
836 connection. The possible values are:
838 acl-drop Another ACL issued a "drop" command
839 bad-commands Too many unknown or non-mail commands
840 command-timeout Timeout while reading SMTP commands
841 connection-lost The SMTP connection has been lost
842 data-timeout Timeout while reading message data
843 local-scan-error The local_scan() function crashed
844 local-scan-timeout The local_scan() function timed out
845 signal-exit SIGTERM or SIGINT
846 synchronization-error SMTP synchronization error
847 tls-failed TLS failed to start
849 In most cases when an SMTP connection is closed without having received
850 QUIT, Exim sends an SMTP response message before actually closing the
851 connection. With the exception of acl-drop, the default message can be
852 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
853 "drop" verb in another ACL, it is the message from the other ACL that is
856 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
857 servers with individual queries. This is done by starting the query with
858 "servers=x:y:z;", where each item in the list may take one of two forms:
860 (1) If it is just a host name, the appropriate global option (mysql_servers
861 or pgsql_servers) is searched for a host of the same name, and the
862 remaining parameters (database, user, password) are taken from there.
864 (2) If it contains any slashes, it is taken as a complete parameter set.
866 The list of servers is used in exactly the same was as the global list.
867 Once a connection to a server has happened and a query has been
868 successfully executed, processing of the lookup ceases.
870 This feature is intended for use in master/slave situations where updates
871 are occurring, and one wants to update a master rather than a slave. If the
872 masters are in the list for reading, you might have:
874 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
876 In an updating lookup, you could then write
878 ${lookup mysql{servers=master; UPDATE ...}
880 If, on the other hand, the master is not to be used for reading lookups:
882 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
884 you can still update the master by
886 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
888 11. The message_body_newlines option (default FALSE, for backwards
889 compatibility) can be used to control whether newlines are present in
890 $message_body and $message_body_end. If it is FALSE, they are replaced by
897 1. There is a new log selector called smtp_no_mail, which is not included in
898 the default setting. When it is set, a line is written to the main log
899 whenever an accepted SMTP connection terminates without having issued a
902 2. When an item in a dnslists list is followed by = and & and a list of IP
903 addresses, the behaviour was not clear when the lookup returned more than
904 one IP address. This has been solved by the addition of == and =& for "all"
905 rather than the default "any" matching.
907 3. Up till now, the only control over which cipher suites GnuTLS uses has been
908 for the cipher algorithms. New options have been added to allow some of the
909 other parameters to be varied.
911 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
912 set, Exim compiles a runtime option called disable_fsync.
914 5. There is a new variable called $smtp_count_at_connection_start.
916 6. There's a new control called no_pipelining.
918 7. There are two new variables called $sending_ip_address and $sending_port.
919 These are set whenever an SMTP connection to another host has been set up.
921 8. The expansion of the helo_data option in the smtp transport now happens
922 after the connection to the server has been made.
924 9. There is a new expansion operator ${rfc2047d: that decodes strings that
925 are encoded as per RFC 2047.
927 10. There is a new log selector called "pid", which causes the current process
928 id to be added to every log line, in square brackets, immediately after the
931 11. Exim has been modified so that it flushes SMTP output before implementing
932 a delay in an ACL. It also flushes the output before performing a callout,
933 as this can take a substantial time. These behaviours can be disabled by
934 obeying control = no_delay_flush or control = no_callout_flush,
935 respectively, at some earlier stage of the connection.
937 12. There are two new expansion conditions that iterate over a list. They are
938 called forany and forall.
940 13. There's a new global option called dsn_from that can be used to vary the
941 contents of From: lines in bounces and other automatically generated
942 messages ("delivery status notifications" - hence the name of the option).
944 14. The smtp transport has a new option called hosts_avoid_pipelining.
946 15. By default, exigrep does case-insensitive matches. There is now a -I option
947 that makes it case-sensitive.
949 16. A number of new features ("addresses", "map", "filter", and "reduce") have
950 been added to string expansions to make it easier to process lists of
951 items, typically addresses.
953 17. There's a new ACL modifier called "continue". It does nothing of itself,
954 and processing of the ACL always continues with the next condition or
955 modifier. It is provided so that the side effects of expanding its argument
958 18. It is now possible to use newline and other control characters (those with
959 values less than 32, plus DEL) as separators in lists.
961 19. The exigrep utility now has a -v option, which inverts the matching
964 20. The host_find_failed option in the manualroute router can now be set to
971 No new features were added to 4.66.
977 No new features were added to 4.65.
983 1. ACL variables can now be given arbitrary names, as long as they start with
984 "acl_c" or "acl_m" (for connection variables and message variables), are at
985 least six characters long, with the sixth character being either a digit or
988 2. There is a new ACL modifier called log_reject_target. It makes it possible
989 to specify which logs are used for messages about ACL rejections.
991 3. There is a new authenticator called "dovecot". This is an interface to the
992 authentication facility of the Dovecot POP/IMAP server, which can support a
993 number of authentication methods.
995 4. The variable $message_headers_raw provides a concatenation of all the
996 messages's headers without any decoding. This is in contrast to
997 $message_headers, which does RFC2047 decoding on the header contents.
999 5. In a DNS black list, if two domain names, comma-separated, are given, the
1000 second is used first to do an initial check, making use of any IP value
1001 restrictions that are set. If there is a match, the first domain is used,
1002 without any IP value restrictions, to get the TXT record.
1004 6. All authenticators now have a server_condition option.
1006 7. There is a new command-line option called -Mset. It is useful only in
1007 conjunction with -be (that is, when testing string expansions). It must be
1008 followed by a message id; Exim loads the given message from its spool
1009 before doing the expansions.
1011 8. Another similar new command-line option is called -bem. It operates like
1012 -be except that it must be followed by the name of a file that contains a
1015 9. When an address is delayed because of a 4xx response to a RCPT command, it
1016 is now the combination of sender and recipient that is delayed in
1017 subsequent queue runs until its retry time is reached.
1019 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1020 shift, have been added to the eval: and eval10: expansion items.
1022 11. The variables $interface_address and $interface_port have been renamed
1023 as $received_ip_address and $received_port, to make it clear that they
1024 relate to message reception rather than delivery. (The old names remain
1025 available for compatibility.)
1027 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1028 to vary the message that is sent when an SMTP command is accepted.
1034 1. There is a new Boolean option called filter_prepend_home for the redirect
1037 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1038 start of receiving a non-SMTP message, before any of the message has been
1041 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1042 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1043 start of the message for an SMTP error code.
1045 4. There is a new parameter for LDAP lookups called "referrals", which takes
1046 one of the settings "follow" (the default) or "nofollow".
1048 5. Version 20070721.2 of exipick now included, offering these new options:
1050 After all other sorting options have bee processed, reverse order
1051 before displaying messages (-R is synonym).
1053 Randomize order of matching messages before displaying.
1055 Instead of displaying the matching messages, display the sum
1057 --sort <variable>[,<variable>...]
1058 Before displaying matching messages, sort the messages according to
1059 each messages value for each variable.
1061 Negate the value for every test (returns inverse output from the
1062 same criteria without --not).
1068 1. The ${readsocket expansion item now supports Internet domain sockets as well
1069 as Unix domain sockets. If the first argument begins "inet:", it must be of
1070 the form "inet:host:port". The port is mandatory; it may be a number or the
1071 name of a TCP port in /etc/services. The host may be a name, or it may be an
1072 IP address. An ip address may optionally be enclosed in square brackets.
1073 This is best for IPv6 addresses. For example:
1075 ${readsocket{inet:[::1]:1234}{<request data>}...
1077 Only a single host name may be given, but if looking it up yield more than
1078 one IP address, they are each tried in turn until a connection is made. Once
1079 a connection has been made, the behaviour is as for ${readsocket with a Unix
1082 2. If a redirect router sets up file or pipe deliveries for more than one
1083 incoming address, and the relevant transport has batch_max set greater than
1084 one, a batch delivery now occurs.
1086 3. The appendfile transport has a new option called maildirfolder_create_regex.
1087 Its value is a regular expression. For a maildir delivery, this is matched
1088 against the maildir directory; if it matches, Exim ensures that a
1089 maildirfolder file is created alongside the new, cur, and tmp directories.
1095 The documentation is up-to-date for the 4.61 release. Major new features since
1096 the 4.60 release are:
1098 . An option called disable_ipv6, to disable the use of IPv6 completely.
1100 . An increase in the number of ACL variables to 20 of each type.
1102 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1103 $2, $3, (though those are still set) because the numeric variables get used
1104 for other things in complicated expansions.
1106 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1108 . It is possible to use setclassresources() on some BSD OS to control the
1109 resources used in pipe deliveries.
1111 . A new ACL modifier called add_header, which can be used with any verb.
1113 . More errors are detectable in retry rules.
1115 There are a number of other additions too.
1121 The documentation is up-to-date for the 4.60 release. Major new features since
1122 the 4.50 release are:
1124 . Support for SQLite.
1126 . Support for IGNOREQUOTA in LMTP.
1128 . Extensions to the "submission mode" features.
1130 . Support for Client SMTP Authorization (CSA).
1132 . Support for ratelimiting hosts and users.
1134 . New expansion items to help with the BATV "prvs" scheme.
1136 . A "match_ip" condition, that matches an IP address against a list.
1138 There are many more minor changes.
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