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 CVS before the documentation is updated. Once
7 the documentation is updated, this file is reduced to a short list.
12 1. The new perl_taintmode option allows to run the embedded perl
13 interpreter in taint mode.
15 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
17 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
20 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
21 N can be 224, 256 (default), 384, 512.
22 With GnuTLS 3.5.0 or later, only.
24 5. Facility for named queues: A command-line argument can specify
25 the queue name for a queue operation, and an ACL modifier can set
26 the queue to be used for a message. A $queue_name variable gives
29 6. New expansion operators base32/base32d.
31 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
32 performance increase and network load decrease. Main config option
33 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
36 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
38 9. Expansion operator escape8bit, like escape but not touching newline etc..
40 10. Feature macros, generated from compile options. All start with "_HAVE_"
41 and go on with some roughly recognisable name. Driver macros, for
42 router, transport and authentication drivers; names starting with "_DRIVER_".
43 Option macros, for each configuration-file option; all start with "_OPT_".
44 Use the "-bP macros" command-line option to see what is present.
46 11. Integer values for options can take a "G" multiplier.
48 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
49 returns from the target back to the initiator, rather than spooling the
52 13. New built-in constants available for tls_dhparam and default changed.
54 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
55 out copies of the message spool files for use by 3rd-party scanners.
57 15. A new option on the smtp transport, hosts_try_fastopen. If the system
58 supports it (on Linux it must be enabled in the kernel by the sysadmin)
59 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
60 but it permits a peer that also supports the facility to send its SMTP
61 banner immediately after the SYN,ACK segment rather then waiting for
62 another ACK - so saving up to one roundtrip time. Because it requires
63 previous communication with the peer (we save a cookie from it) this
64 will only become active on frequently-contacted destinations.
66 16. A new syslog_pid option to suppress PID duplication in syslog lines.
72 1. The ACL conditions regex and mime_regex now capture substrings
73 into numeric variables $regex1 to 9, like the "match" expansion condition.
75 2. New $callout_address variable records the address used for a spam=,
76 malware= or verify= callout.
78 3. Transports now take a "max_parallel" option, to limit concurrency.
80 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
81 The latter expands to a 8-element colon-sep set of hex digits including
82 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
83 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
84 The former operator strips leading zeroes and collapses the longest
85 set of 0-groups to a double-colon.
87 5. New "-bP config" support, to dump the effective configuration.
89 6. New $dkim_key_length variable.
91 7. New base64d and base64 expansion items (the existing str2b64 being a
92 synonym of the latter). Add support in base64 for certificates.
94 8. New main configuration option "bounce_return_linesize_limit" to
95 avoid oversize bodies in bounces. The default value matches RFC
98 9. New $initial_cwd expansion variable.
104 1. Support for using the system standard CA bundle.
106 2. New expansion items $config_file, $config_dir, containing the file
107 and directory name of the main configuration file. Also $exim_version.
109 3. New "malware=" support for Avast.
111 4. New "spam=" variant option for Rspamd.
113 5. Assorted options on malware= and spam= scanners.
115 6. A command-line option to write a comment into the logfile.
117 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
118 be configured to make connections via socks5 proxies.
120 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
121 the transmission of UTF-8 envelope addresses.
123 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
124 used encoding of Maildir folder names.
126 10. A logging option for slow DNS lookups.
128 11. New ${env {<variable>}} expansion.
130 12. A non-SMTP authenticator using information from TLS client certificates.
132 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
133 Patch originally by Wolfgang Breyha.
135 14. Main option "dns_trust_aa" for trusting your local nameserver at the
136 same level as DNSSEC.
142 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
143 DANE SMTP draft to assess a secure chain of trust of the certificate
144 used to establish the TLS connection based on a TLSA record in the
145 domain of the sender.
147 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
148 and several new events have been created. The reason is because it has
149 been expanded beyond just firing events during the transport phase. Any
150 existing TPDA transport options will have to be rewritten to use a new
151 $event_name expansion variable in a condition. Refer to the
152 experimental-spec.txt for details and examples.
154 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
155 server certs used for TLS match the result of the MX lookup. It does
156 not use the same mechanism as DANE.
166 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
167 configured to expect an initial header from a proxy that will make the
168 actual external source IP:host be used in exim instead of the IP of the
169 proxy that is connecting to it.
171 2. New verify option header_names_ascii, which will check to make sure
172 there are no non-ASCII characters in header names. Exim itself handles
173 those non-ASCII characters, but downstream apps may not, so Exim can
174 detect and reject if those characters are present.
176 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
177 codepoints with valid ones.
179 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
180 command line and matching a regex against the return data for trigger
181 and a second regex to extract malware_name. The mail spoolfile name can
182 be included in the command line.
184 5. The smtp transport now supports options "tls_verify_hosts" and
185 "tls_try_verify_hosts". If either is set the certificate verification
186 is split from the encryption operation. The default remains that a failed
187 verification cancels the encryption.
189 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
190 lookup can now set a list of servers to use that is different from the
193 7. New command-line option -C for exiqgrep to specify alternate exim.conf
194 file when searching the queue.
196 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
198 9. Support for DNSSEC on outbound connections.
200 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
201 "certextract" to extract fields from them. Hash operators md5 and sha1
202 work over them for generating fingerprints, and a new sha256 operator
205 11. PRDR is now supported dy default.
207 12. OCSP stapling is now supported by default.
209 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
210 Delivery Status Notification messages in MIME format, and negociate
211 DSN features per RFC 3461.
217 1. New command-line option -bI:sieve will list all supported sieve extensions
218 of this Exim build on standard output, one per line.
219 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
220 query this to establish the correct list to include in the protocol's
221 SIEVE capability line.
223 2. If the -n option is combined with the -bP option, then the name of an
224 emitted option is not output, only the value (if visible to you).
225 For instance, "exim -n -bP pid_file_path" should just emit a pathname
226 followed by a newline, and no other text.
228 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
229 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
230 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
231 acceptable for security. (Option accepted but ignored if using OpenSSL).
232 Defaults to 1024, the old value. May be lowered only to 512, or raised as
233 far as you like. Raising this may hinder TLS interoperability with other
234 sites and is not currently recommended. Lowering this will permit you to
235 establish a TLS session which is not as secure as you might like.
237 Unless you really know what you are doing, leave it alone.
239 4. If not built with DISABLE_DNSSEC, Exim now has the main option
240 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
241 to send the DO flag to your recursive resolver. If you have a recursive
242 resolver, which can set the Authenticated Data (AD) flag in results, Exim
243 can now detect this. Exim does not perform validation itself, instead
244 relying upon a trusted path to the resolver.
246 Current status: work-in-progress; $sender_host_dnssec variable added.
248 5. DSCP support for outbound connections: on a transport using the smtp driver,
249 set "dscp = ef", for instance, to cause the connections to have the relevant
250 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
252 Similarly for inbound connections, there is a new control modifier, dscp,
253 so "warn control = dscp/ef" in the connect ACL, or after authentication.
255 Supported values depend upon system libraries. "exim -bI:dscp" to list the
256 ones Exim knows of. You can also set a raw number 0..0x3F.
258 6. The -G command-line flag is no longer ignored; it is now equivalent to an
259 ACL setting "control = suppress_local_fixups". The -L command-line flag
260 is now accepted and forces use of syslog, with the provided tag as the
261 process name. A few other flags used by Sendmail are now accepted and
264 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
265 ACL modifier; works for single-recipient mails which are recieved on and
266 deliverable via SMTP. Using the connection made for a recipient verify,
267 if requested before the verify, or a new one made for the purpose while
268 the inbound connection is still active. The bulk of the mail item is copied
269 direct from the inbound socket to the outbound (as well as the spool file).
270 When the source notifies the end of data, the data acceptance by the destination
271 is negociated before the acceptance is sent to the source. If the destination
272 does not accept the mail item, for example due to content-scanning, the item
273 is not accepted from the source and therefore there is no need to generate
274 a bounce mail. This is of benefit when providing a secondary-MX service.
275 The downside is that delays are under the control of the ultimate destination
278 The Recieved-by: header on items delivered by cutthrough is generated
279 early in reception rather than at the end; this will affect any timestamp
280 included. The log line showing delivery is recorded before that showing
281 reception; it uses a new ">>" tag instead of "=>".
283 To support the feature, verify-callout connections can now use ESMTP and TLS.
284 The usual smtp transport options are honoured, plus a (new, default everything)
285 hosts_verify_avoid_tls.
287 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
288 for specific access to the information for each connection. The old names
289 are present for now but deprecated.
291 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
293 8. New expansion operators ${listnamed:name} to get the content of a named list
294 and ${listcount:string} to count the items in a list.
296 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
297 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
298 modules. For some situations this is desirable, but we expect admin in
299 those situations to know they want the feature. More commonly, it means
300 that GUI user modules get loaded and are broken by the setuid Exim being
301 unable to access files specified in environment variables and passed
302 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
303 unless this new option is set.
305 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
306 so have also added a build option which can be used to build Exim with GnuTLS
307 but without trying to use any kind of PKCS11 support. Uncomment this in the
310 AVOID_GNUTLS_PKCS11=yes
312 10. The "acl = name" condition on an ACL now supports optional arguments.
313 New expansion item "${acl {name}{arg}...}" and expansion condition
314 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
315 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
316 Variable $acl_narg contains the number of arguments. If the ACL sets
317 a "message =" value this becomes the result of the expansion item,
318 or the value of $value for the expansion condition. If the ACL returns
319 accept the expansion condition is true; if reject, false. A defer
320 return results in a forced fail.
322 11. Routers and transports can now have multiple headers_add and headers_remove
323 option lines. The concatenated list is used.
325 12. New ACL modifier "remove_header" can remove headers before message gets
326 handled by routers/transports.
328 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
329 "aaaa" and "a" lookups is done and the full set of results returned.
331 14. New expansion variable $headers_added with content from ACL add_header
332 modifier (but not yet added to message).
334 15. New 8bitmime status logging option for received messages. Log field "M8S".
336 16. New authenticated_sender logging option, adding to log field "A".
338 17. New expansion variables $router_name and $transport_name. Useful
339 particularly for debug_print as -bt command-line option does not
340 require privilege whereas -d does.
342 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
343 proposed extension to SMTP from Eric Hall.
345 19. The pipe transport has gained the force_command option, to allow
346 decorating commands from user .forward pipe aliases with prefix
347 wrappers, for instance.
349 20. Callout connections can now AUTH; the same controls as normal delivery
352 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
353 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
354 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
355 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
356 dmarc_status. It adds new control flags dmarc_disable_verify and
357 dmarc_enable_forensic.
359 22. Add expansion variable $authenticated_fail_id, which is the username
360 provided to the authentication method which failed. It is available
361 for use in subsequent ACL processing (typically quit or notquit ACLs).
363 23. New ACL modifer "udpsend" can construct a UDP packet to send to a given
366 24. New ${hexquote:..string..} expansion operator converts non-printable
367 characters in the string to \xNN form.
369 25. Experimental TPDA (Transport Post Delivery Action) function added.
370 Patch provided by Axel Rau.
372 26. Experimental Redis lookup added. Patch provided by Warren Baker.
378 1. New authenticator driver, "gsasl". Server-only (at present).
379 This is a SASL interface, licensed under GPL, which can be found at
380 http://www.gnu.org/software/gsasl/.
381 This system does not provide sources of data for authentication, so
382 careful use needs to be made of the conditions in Exim.
384 2. New authenticator driver, "heimdal_gssapi". Server-only.
385 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
386 is no longer honoured for setuid programs by Heimdal. Use the
387 "server_keytab" option to point to the keytab.
389 3. The "pkg-config" system can now be used when building Exim to reference
390 cflags and library information for lookups and authenticators, rather
391 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
392 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
393 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
395 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
396 find the headers and libraries for PCRE.
398 4. New expansion variable $tls_bits.
400 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
401 be joined together with ASCII NUL characters to construct the key to pass
402 into the DBM library. Can be used with gsasl to access sasldb2 files as
405 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
407 Avoid release 1.0.1a if you can. Note that the default value of
408 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
409 increased susceptibility to attack. This may still have interoperability
410 implications for very old clients (see version 4.31 change 37) but
411 administrators can choose to make the trade-off themselves and restore
412 compatibility at the cost of session security.
414 7. Use of the new expansion variable $tls_sni in the main configuration option
415 tls_certificate will cause Exim to re-expand the option, if the client
416 sends the TLS Server Name Indication extension, to permit choosing a
417 different certificate; tls_privatekey will also be re-expanded. You must
418 still set these options to expand to valid files when $tls_sni is not set.
420 The SMTP Transport has gained the option tls_sni, which will set a hostname
421 for outbound TLS sessions, and set $tls_sni too.
423 A new log_selector, +tls_sni, has been added, to log received SNI values
424 for Exim as a server.
426 8. The existing "accept_8bitmime" option now defaults to true. This means
427 that Exim is deliberately not strictly RFC compliant. We're following
428 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
429 Those who disagree, or know that they are talking to mail servers that,
430 even today, are not 8-bit clean, need to turn off this option.
432 9. Exim can now be started with -bw (with an optional timeout, given as
433 -bw<timespec>). With this, stdin at startup is a socket that is
434 already listening for connections. This has a more modern name of
435 "socket activation", but forcing the activated socket to fd 0. We're
436 interested in adding more support for modern variants.
438 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
439 for numbers indicates multiplication by 1024^3.
441 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
442 gnutls_require_mac & gnutls_require_protocols are no longer supported.
443 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
444 string, documentation for which is at:
445 http://www.gnutls.org/manual/html_node/Priority-Strings.html
447 SNI support has been added to Exim's GnuTLS integration too.
449 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
450 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
452 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
453 is now available. If the contents of the file are valid, then Exim will
454 send that back in response to a TLS status request; this is OCSP Stapling.
455 Exim will not maintain the contents of the file in any way: administrators
456 are responsible for ensuring that it is up-to-date.
458 See "experimental-spec.txt" for more details.
460 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
461 identically to TXT record lookups.
463 14. New expansion variable $tod_epoch_l for higher-precision time.
465 15. New global option tls_dh_max_bits, defaulting to current value of NSS
466 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
467 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
469 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
470 Option can now be a path or an identifier for a standard prime.
471 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
472 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
475 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
476 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
477 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
483 1. New options for the ratelimit ACL condition: /count= and /unique=.
484 The /noupdate option has been replaced by a /readonly option.
486 2. The SMTP transport's protocol option may now be set to "smtps", to
487 use SSL-on-connect outbound.
489 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
490 there is a problem talking to the AV scanner, or the AV scanner running.
492 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
493 and check if the search item is a member of the list. This does not
494 support named lists, but does subject the list part to string expansion.
496 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
497 built, Exim no longer performs string expansion on the second string of
498 the match_* expansion conditions: "match_address", "match_domain",
499 "match_ip" & "match_local_part". Named lists can still be used.
505 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
506 or off in the resolver library.
512 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
513 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
514 libraries. The following global options have been added in support of
515 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
516 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
518 2. The pipe transport now takes a boolean option, "freeze_signal", default
519 false. When true, if the external delivery command exits on a signal then
520 Exim will freeze the message in the queue, instead of generating a bounce.
522 3. Log filenames may now use %M as an escape, instead of %D (still available).
523 The %M pattern expands to yyyymm, providing month-level resolution.
525 4. The $message_linecount variable is now updated for the maildir_tag option,
526 in the same way as $message_size, to reflect the real number of lines,
527 including any header additions or removals from transport.
529 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
530 Exim now selects entries randomly, to better scale in a cluster setup.
536 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
537 the flaw permitted the Exim run-time user to cause root to append to
538 arbitrary files of the attacker's choosing, with the content based
539 on content supplied by the attacker.
541 2. Exim now supports loading some lookup types at run-time, using your
542 platform's dlopen() functionality. This has limited platform support
543 and the intention is not to support every variant, it's limited to
544 dlopen(). This permits the main Exim binary to not be linked against
545 all the libraries needed for all the lookup types.
551 NOTE: this version is not guaranteed backwards-compatible, please read the
552 items below carefully
554 1. A new main configuration option, "openssl_options", is available if Exim
555 is built with SSL support provided by OpenSSL. The option allows
556 administrators to specify OpenSSL options to be used on connections;
557 typically this is to set bug compatibility features which the OpenSSL
558 developers have not enabled by default. There may be security
559 consequences for certain options, so these should not be changed
562 2. A new pipe transport option, "permit_coredumps", may help with problem
563 diagnosis in some scenarios. Note that Exim is typically installed as
564 a setuid binary, which on most OSes will inhibit coredumps by default,
565 so that safety mechanism would have to be overridden for this option to
566 be able to take effect.
568 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
569 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
570 Note that this switches Exim to use a new API ("INSTREAM") and a future
571 release of ClamAV will remove support for the old API ("STREAM").
573 The av_scanner option, when set to "clamd", now takes an optional third
574 part, "local", which causes Exim to pass a filename to ClamAV instead of
575 the file content. This is the same behaviour as when clamd is pointed at
576 a Unix-domain socket. For example:
578 av_scanner = clamd:192.0.2.3 1234:local
580 ClamAV's ExtendedDetectionInfo response format is now handled.
582 4. There is now a -bmalware option, restricted to admin users. This option
583 takes one parameter, a filename, and scans that file with Exim's
584 malware-scanning framework. This is intended purely as a debugging aid
585 to ensure that Exim's scanning is working, not to replace other tools.
586 Note that the ACL framework is not invoked, so if av_scanner references
587 ACL variables without a fallback then this will fail.
589 5. There is a new expansion operator, "reverse_ip", which will reverse IP
590 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
592 ${reverse_ip:192.0.2.4}
594 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
595 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
597 6. There is a new ACL control called "debug", to enable debug logging.
598 This allows selective logging of certain incoming transactions within
599 production environments, with some care. It takes two options, "tag"
600 and "opts"; "tag" is included in the filename of the log and "opts"
601 is used as per the -d<options> command-line option. Examples, which
602 don't all make sense in all contexts:
605 control = debug/tag=.$sender_host_address
606 control = debug/opts=+expand+acl
607 control = debug/tag=.$message_exim_id/opts=+expand
609 7. It has always been implicit in the design and the documentation that
610 "the Exim user" is not root. src/EDITME said that using root was
611 "very strongly discouraged". This is not enough to keep people from
612 shooting themselves in the foot in days when many don't configure Exim
613 themselves but via package build managers. The security consequences of
614 running various bits of network code are severe if there should be bugs in
615 them. As such, the Exim user may no longer be root. If configured
616 statically, Exim will refuse to build. If configured as ref:user then Exim
617 will exit shortly after start-up. If you must shoot yourself in the foot,
618 then henceforth you will have to maintain your own local patches to strip
621 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
622 condition logic to determine truth/failure and will fail to expand many
623 strings, bool_lax{} uses the router condition logic, where most strings
625 Note: bool{00} is false, bool_lax{00} is true.
627 9. Routers now support multiple "condition" tests.
629 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
630 Setting this allows an admin to define which entry in the tcpwrappers
631 config file will be used to control access to the daemon. This option
632 is only available when Exim is built with USE_TCP_WRAPPERS. The
633 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
636 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
637 the Exim run-time user, instead of root.
639 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
640 is forced on. This is mitigated by the new build option
641 TRUSTED_CONFIG_LIST which defines a list of configuration files which
642 are trusted; one per line. If a config file is owned by root and matches
643 a pathname in the list, then it may be invoked by the Exim build-time
644 user without Exim relinquishing root privileges.
646 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
647 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
648 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
649 include the main config. As a transition mechanism, we are temporarily
650 providing a work-around: the new build option WHITELIST_D_MACROS provides
651 a colon-separated list of macro names which may be overridden by the Exim
652 run-time user. The values of these macros are constrained to the regex
653 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
659 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
660 writable, the other to locking of MBX folders (not mbox).
662 2. MySQL stored procedures are now supported.
664 3. The dkim_domain transport option is now a list, not a single string, and
665 messages will be signed for each element in the list (discarding
668 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
669 in the presence of multiple character strings within the RR. Prior to 4.70,
670 only the first string would be returned. The dnsdb lookup now, by default,
671 preserves the pre-4.70 semantics, but also now takes an extended output
672 separator specification. The separator can be followed by a semicolon, to
673 concatenate the individual text strings together with no join character,
674 or by a comma and a second separator character, in which case the text
675 strings within a TXT record are joined on that second character.
676 Administrators are reminded that DNS provides no ordering guarantees
677 between multiple records in an RRset. For example:
679 foo.example. IN TXT "a" "b" "c"
680 foo.example. IN TXT "d" "e" "f"
682 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
683 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
684 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
690 1. Native DKIM support without an external library.
691 (Note that if no action to prevent it is taken, a straight upgrade will
692 result in DKIM verification of all signed incoming emails. See spec
693 for details on conditionally disabling)
695 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
697 3. There is now a bool{} expansion condition which maps certain strings to
698 true/false condition values (most likely of use in conjunction with the
699 and{} expansion operator).
701 4. The $spam_score, $spam_bar and $spam_report variables are now available
704 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
705 options, provided that Exim is invoked by an admin_user.
707 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
708 which increases compatibility with older clients at the cost of decreased
709 security. Don't set this unless you need to support such clients.
711 7. There is a new expansion operator, ${randint:...} which will produce a
712 "random" number less than the supplied integer. This randomness is
713 not guaranteed to be cryptographically strong, but depending upon how
714 Exim was built may be better than the most naive schemes.
716 8. Exim now explicitly ensures that SHA256 is available when linked against
719 9. The transport_filter_timeout option now applies to SMTP transports too.
725 1. Preliminary DKIM support in Experimental.
731 1. The body_linecount and body_zerocount C variables are now exported in the
734 2. When a dnslists lookup succeeds, the key that was looked up is now placed
735 in $dnslist_matched. When the key is an IP address, it is not reversed in
736 this variable (though it is, of course, in the actual lookup). In simple
739 deny dnslists = spamhaus.example
741 the key is also available in another variable (in this case,
742 $sender_host_address). In more complicated cases, however, this is not
743 true. For example, using a data lookup might generate a dnslists lookup
746 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
748 If this condition succeeds, the value in $dnslist_matched might be
749 192.168.6.7 (for example).
751 3. Authenticators now have a client_condition option. When Exim is running as
752 a client, it skips an authenticator whose client_condition expansion yields
753 "0", "no", or "false". This can be used, for example, to skip plain text
754 authenticators when the connection is not encrypted by a setting such as:
756 client_condition = ${if !eq{$tls_cipher}{}}
758 Note that the 4.67 documentation states that $tls_cipher contains the
759 cipher used for incoming messages. In fact, during SMTP delivery, it
760 contains the cipher used for the delivery. The same is true for
763 4. There is now a -Mvc <message-id> option, which outputs a copy of the
764 message to the standard output, in RFC 2822 format. The option can be used
765 only by an admin user.
767 5. There is now a /noupdate option for the ratelimit ACL condition. It
768 computes the rate and checks the limit as normal, but it does not update
769 the saved data. This means that, in relevant ACLs, it is possible to lookup
770 the existence of a specified (or auto-generated) ratelimit key without
771 incrementing the ratelimit counter for that key.
773 In order for this to be useful, another ACL entry must set the rate
774 for the same key somewhere (otherwise it will always be zero).
779 # Read the rate; if it doesn't exist or is below the maximum
781 deny ratelimit = 100 / 5m / strict / noupdate
782 log_message = RATE: $sender_rate / $sender_rate_period \
783 (max $sender_rate_limit)
785 [... some other logic and tests...]
787 warn ratelimit = 100 / 5m / strict / per_cmd
788 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
789 (max $sender_rate_limit)
790 condition = ${if le{$sender_rate}{$sender_rate_limit}}
794 6. The variable $max_received_linelength contains the number of bytes in the
795 longest line that was received as part of the message, not counting the
796 line termination character(s).
798 7. Host lists can now include +ignore_defer and +include_defer, analagous to
799 +ignore_unknown and +include_unknown. These options should be used with
800 care, probably only in non-critical host lists such as whitelists.
802 8. There's a new option called queue_only_load_latch, which defaults true.
803 If set false when queue_only_load is greater than zero, Exim re-evaluates
804 the load for each incoming message in an SMTP session. Otherwise, once one
805 message is queued, the remainder are also.
807 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
808 cases when an SMTP session ends without sending QUIT. However, when Exim
809 itself is is bad trouble, such as being unable to write to its log files,
810 this ACL is not run, because it might try to do things (such as write to
811 log files) that make the situation even worse.
813 Like the QUIT ACL, this new ACL is provided to make it possible to gather
814 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
815 modifier is forbidden in this ACL.
817 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
818 to a string that indicates the reason for the termination of the SMTP
819 connection. The possible values are:
821 acl-drop Another ACL issued a "drop" command
822 bad-commands Too many unknown or non-mail commands
823 command-timeout Timeout while reading SMTP commands
824 connection-lost The SMTP connection has been lost
825 data-timeout Timeout while reading message data
826 local-scan-error The local_scan() function crashed
827 local-scan-timeout The local_scan() function timed out
828 signal-exit SIGTERM or SIGINT
829 synchronization-error SMTP synchronization error
830 tls-failed TLS failed to start
832 In most cases when an SMTP connection is closed without having received
833 QUIT, Exim sends an SMTP response message before actually closing the
834 connection. With the exception of acl-drop, the default message can be
835 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
836 "drop" verb in another ACL, it is the message from the other ACL that is
839 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
840 servers with individual queries. This is done by starting the query with
841 "servers=x:y:z;", where each item in the list may take one of two forms:
843 (1) If it is just a host name, the appropriate global option (mysql_servers
844 or pgsql_servers) is searched for a host of the same name, and the
845 remaining parameters (database, user, password) are taken from there.
847 (2) If it contains any slashes, it is taken as a complete parameter set.
849 The list of servers is used in exactly the same was as the global list.
850 Once a connection to a server has happened and a query has been
851 successfully executed, processing of the lookup ceases.
853 This feature is intended for use in master/slave situations where updates
854 are occurring, and one wants to update a master rather than a slave. If the
855 masters are in the list for reading, you might have:
857 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
859 In an updating lookup, you could then write
861 ${lookup mysql{servers=master; UPDATE ...}
863 If, on the other hand, the master is not to be used for reading lookups:
865 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
867 you can still update the master by
869 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
871 11. The message_body_newlines option (default FALSE, for backwards
872 compatibility) can be used to control whether newlines are present in
873 $message_body and $message_body_end. If it is FALSE, they are replaced by
880 1. There is a new log selector called smtp_no_mail, which is not included in
881 the default setting. When it is set, a line is written to the main log
882 whenever an accepted SMTP connection terminates without having issued a
885 2. When an item in a dnslists list is followed by = and & and a list of IP
886 addresses, the behaviour was not clear when the lookup returned more than
887 one IP address. This has been solved by the addition of == and =& for "all"
888 rather than the default "any" matching.
890 3. Up till now, the only control over which cipher suites GnuTLS uses has been
891 for the cipher algorithms. New options have been added to allow some of the
892 other parameters to be varied.
894 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
895 set, Exim compiles a runtime option called disable_fsync.
897 5. There is a new variable called $smtp_count_at_connection_start.
899 6. There's a new control called no_pipelining.
901 7. There are two new variables called $sending_ip_address and $sending_port.
902 These are set whenever an SMTP connection to another host has been set up.
904 8. The expansion of the helo_data option in the smtp transport now happens
905 after the connection to the server has been made.
907 9. There is a new expansion operator ${rfc2047d: that decodes strings that
908 are encoded as per RFC 2047.
910 10. There is a new log selector called "pid", which causes the current process
911 id to be added to every log line, in square brackets, immediately after the
914 11. Exim has been modified so that it flushes SMTP output before implementing
915 a delay in an ACL. It also flushes the output before performing a callout,
916 as this can take a substantial time. These behaviours can be disabled by
917 obeying control = no_delay_flush or control = no_callout_flush,
918 respectively, at some earlier stage of the connection.
920 12. There are two new expansion conditions that iterate over a list. They are
921 called forany and forall.
923 13. There's a new global option called dsn_from that can be used to vary the
924 contents of From: lines in bounces and other automatically generated
925 messages ("delivery status notifications" - hence the name of the option).
927 14. The smtp transport has a new option called hosts_avoid_pipelining.
929 15. By default, exigrep does case-insensitive matches. There is now a -I option
930 that makes it case-sensitive.
932 16. A number of new features ("addresses", "map", "filter", and "reduce") have
933 been added to string expansions to make it easier to process lists of
934 items, typically addresses.
936 17. There's a new ACL modifier called "continue". It does nothing of itself,
937 and processing of the ACL always continues with the next condition or
938 modifier. It is provided so that the side effects of expanding its argument
941 18. It is now possible to use newline and other control characters (those with
942 values less than 32, plus DEL) as separators in lists.
944 19. The exigrep utility now has a -v option, which inverts the matching
947 20. The host_find_failed option in the manualroute router can now be set to
954 No new features were added to 4.66.
960 No new features were added to 4.65.
966 1. ACL variables can now be given arbitrary names, as long as they start with
967 "acl_c" or "acl_m" (for connection variables and message variables), are at
968 least six characters long, with the sixth character being either a digit or
971 2. There is a new ACL modifier called log_reject_target. It makes it possible
972 to specify which logs are used for messages about ACL rejections.
974 3. There is a new authenticator called "dovecot". This is an interface to the
975 authentication facility of the Dovecot POP/IMAP server, which can support a
976 number of authentication methods.
978 4. The variable $message_headers_raw provides a concatenation of all the
979 messages's headers without any decoding. This is in contrast to
980 $message_headers, which does RFC2047 decoding on the header contents.
982 5. In a DNS black list, if two domain names, comma-separated, are given, the
983 second is used first to do an initial check, making use of any IP value
984 restrictions that are set. If there is a match, the first domain is used,
985 without any IP value restrictions, to get the TXT record.
987 6. All authenticators now have a server_condition option.
989 7. There is a new command-line option called -Mset. It is useful only in
990 conjunction with -be (that is, when testing string expansions). It must be
991 followed by a message id; Exim loads the given message from its spool
992 before doing the expansions.
994 8. Another similar new command-line option is called -bem. It operates like
995 -be except that it must be followed by the name of a file that contains a
998 9. When an address is delayed because of a 4xx response to a RCPT command, it
999 is now the combination of sender and recipient that is delayed in
1000 subsequent queue runs until its retry time is reached.
1002 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1003 shift, have been added to the eval: and eval10: expansion items.
1005 11. The variables $interface_address and $interface_port have been renamed
1006 as $received_ip_address and $received_port, to make it clear that they
1007 relate to message reception rather than delivery. (The old names remain
1008 available for compatibility.)
1010 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1011 to vary the message that is sent when an SMTP command is accepted.
1017 1. There is a new Boolean option called filter_prepend_home for the redirect
1020 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1021 start of receiving a non-SMTP message, before any of the message has been
1024 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1025 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1026 start of the message for an SMTP error code.
1028 4. There is a new parameter for LDAP lookups called "referrals", which takes
1029 one of the settings "follow" (the default) or "nofollow".
1031 5. Version 20070721.2 of exipick now included, offering these new options:
1033 After all other sorting options have bee processed, reverse order
1034 before displaying messages (-R is synonym).
1036 Randomize order of matching messages before displaying.
1038 Instead of displaying the matching messages, display the sum
1040 --sort <variable>[,<variable>...]
1041 Before displaying matching messages, sort the messages according to
1042 each messages value for each variable.
1044 Negate the value for every test (returns inverse output from the
1045 same criteria without --not).
1051 1. The ${readsocket expansion item now supports Internet domain sockets as well
1052 as Unix domain sockets. If the first argument begins "inet:", it must be of
1053 the form "inet:host:port". The port is mandatory; it may be a number or the
1054 name of a TCP port in /etc/services. The host may be a name, or it may be an
1055 IP address. An ip address may optionally be enclosed in square brackets.
1056 This is best for IPv6 addresses. For example:
1058 ${readsocket{inet:[::1]:1234}{<request data>}...
1060 Only a single host name may be given, but if looking it up yield more than
1061 one IP address, they are each tried in turn until a connection is made. Once
1062 a connection has been made, the behaviour is as for ${readsocket with a Unix
1065 2. If a redirect router sets up file or pipe deliveries for more than one
1066 incoming address, and the relevant transport has batch_max set greater than
1067 one, a batch delivery now occurs.
1069 3. The appendfile transport has a new option called maildirfolder_create_regex.
1070 Its value is a regular expression. For a maildir delivery, this is matched
1071 against the maildir directory; if it matches, Exim ensures that a
1072 maildirfolder file is created alongside the new, cur, and tmp directories.
1078 The documentation is up-to-date for the 4.61 release. Major new features since
1079 the 4.60 release are:
1081 . An option called disable_ipv6, to disable the use of IPv6 completely.
1083 . An increase in the number of ACL variables to 20 of each type.
1085 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1086 $2, $3, (though those are still set) because the numeric variables get used
1087 for other things in complicated expansions.
1089 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1091 . It is possible to use setclassresources() on some BSD OS to control the
1092 resources used in pipe deliveries.
1094 . A new ACL modifier called add_header, which can be used with any verb.
1096 . More errors are detectable in retry rules.
1098 There are a number of other additions too.
1104 The documentation is up-to-date for the 4.60 release. Major new features since
1105 the 4.50 release are:
1107 . Support for SQLite.
1109 . Support for IGNOREQUOTA in LMTP.
1111 . Extensions to the "submission mode" features.
1113 . Support for Client SMTP Authorization (CSA).
1115 . Support for ratelimiting hosts and users.
1117 . New expansion items to help with the BATV "prvs" scheme.
1119 . A "match_ip" condition, that matches an IP address against a list.
1121 There are many more minor changes.
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