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.
13 1. Allow relative config file names for ".include"
19 1. The new perl_taintmode option allows to run the embedded perl
20 interpreter in taint mode.
22 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
24 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
27 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
28 N can be 224, 256 (default), 384, 512.
29 With GnuTLS 3.5.0 or later, only.
31 5. Facility for named queues: A command-line argument can specify
32 the queue name for a queue operation, and an ACL modifier can set
33 the queue to be used for a message. A $queue_name variable gives
36 6. New expansion operators base32/base32d.
38 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
39 performance increase and network load decrease. Main config option
40 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
43 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
45 9. Expansion operator escape8bit, like escape but not touching newline etc..
47 10. Feature macros, generated from compile options. All start with "_HAVE_"
48 and go on with some roughly recognisable name. Driver macros, for
49 router, transport and authentication drivers; names starting with "_DRIVER_".
50 Option macros, for each configuration-file option; all start with "_OPT_".
51 Use the "-bP macros" command-line option to see what is present.
53 11. Integer values for options can take a "G" multiplier.
55 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
56 returns from the target back to the initiator, rather than spooling the
59 13. New built-in constants available for tls_dhparam and default changed.
61 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
62 out copies of the message spool files for use by 3rd-party scanners.
64 15. A new option on the smtp transport, hosts_try_fastopen. If the system
65 supports it (on Linux it must be enabled in the kernel by the sysadmin)
66 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
67 but it permits a peer that also supports the facility to send its SMTP
68 banner immediately after the SYN,ACK segment rather then waiting for
69 another ACK - so saving up to one roundtrip time. Because it requires
70 previous communication with the peer (we save a cookie from it) this
71 will only become active on frequently-contacted destinations.
73 16. A new syslog_pid option to suppress PID duplication in syslog lines.
79 1. The ACL conditions regex and mime_regex now capture substrings
80 into numeric variables $regex1 to 9, like the "match" expansion condition.
82 2. New $callout_address variable records the address used for a spam=,
83 malware= or verify= callout.
85 3. Transports now take a "max_parallel" option, to limit concurrency.
87 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
88 The latter expands to a 8-element colon-sep set of hex digits including
89 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
90 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
91 The former operator strips leading zeroes and collapses the longest
92 set of 0-groups to a double-colon.
94 5. New "-bP config" support, to dump the effective configuration.
96 6. New $dkim_key_length variable.
98 7. New base64d and base64 expansion items (the existing str2b64 being a
99 synonym of the latter). Add support in base64 for certificates.
101 8. New main configuration option "bounce_return_linesize_limit" to
102 avoid oversize bodies in bounces. The default value matches RFC
105 9. New $initial_cwd expansion variable.
111 1. Support for using the system standard CA bundle.
113 2. New expansion items $config_file, $config_dir, containing the file
114 and directory name of the main configuration file. Also $exim_version.
116 3. New "malware=" support for Avast.
118 4. New "spam=" variant option for Rspamd.
120 5. Assorted options on malware= and spam= scanners.
122 6. A command-line option to write a comment into the logfile.
124 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
125 be configured to make connections via socks5 proxies.
127 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
128 the transmission of UTF-8 envelope addresses.
130 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
131 used encoding of Maildir folder names.
133 10. A logging option for slow DNS lookups.
135 11. New ${env {<variable>}} expansion.
137 12. A non-SMTP authenticator using information from TLS client certificates.
139 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
140 Patch originally by Wolfgang Breyha.
142 14. Main option "dns_trust_aa" for trusting your local nameserver at the
143 same level as DNSSEC.
149 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
150 DANE SMTP draft to assess a secure chain of trust of the certificate
151 used to establish the TLS connection based on a TLSA record in the
152 domain of the sender.
154 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
155 and several new events have been created. The reason is because it has
156 been expanded beyond just firing events during the transport phase. Any
157 existing TPDA transport options will have to be rewritten to use a new
158 $event_name expansion variable in a condition. Refer to the
159 experimental-spec.txt for details and examples.
161 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
162 server certs used for TLS match the result of the MX lookup. It does
163 not use the same mechanism as DANE.
173 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
174 configured to expect an initial header from a proxy that will make the
175 actual external source IP:host be used in exim instead of the IP of the
176 proxy that is connecting to it.
178 2. New verify option header_names_ascii, which will check to make sure
179 there are no non-ASCII characters in header names. Exim itself handles
180 those non-ASCII characters, but downstream apps may not, so Exim can
181 detect and reject if those characters are present.
183 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
184 codepoints with valid ones.
186 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
187 command line and matching a regex against the return data for trigger
188 and a second regex to extract malware_name. The mail spoolfile name can
189 be included in the command line.
191 5. The smtp transport now supports options "tls_verify_hosts" and
192 "tls_try_verify_hosts". If either is set the certificate verification
193 is split from the encryption operation. The default remains that a failed
194 verification cancels the encryption.
196 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
197 lookup can now set a list of servers to use that is different from the
200 7. New command-line option -C for exiqgrep to specify alternate exim.conf
201 file when searching the queue.
203 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
205 9. Support for DNSSEC on outbound connections.
207 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
208 "certextract" to extract fields from them. Hash operators md5 and sha1
209 work over them for generating fingerprints, and a new sha256 operator
212 11. PRDR is now supported dy default.
214 12. OCSP stapling is now supported by default.
216 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
217 Delivery Status Notification messages in MIME format, and negotiate
218 DSN features per RFC 3461.
224 1. New command-line option -bI:sieve will list all supported sieve extensions
225 of this Exim build on standard output, one per line.
226 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
227 query this to establish the correct list to include in the protocol's
228 SIEVE capability line.
230 2. If the -n option is combined with the -bP option, then the name of an
231 emitted option is not output, only the value (if visible to you).
232 For instance, "exim -n -bP pid_file_path" should just emit a pathname
233 followed by a newline, and no other text.
235 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
236 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
237 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
238 acceptable for security. (Option accepted but ignored if using OpenSSL).
239 Defaults to 1024, the old value. May be lowered only to 512, or raised as
240 far as you like. Raising this may hinder TLS interoperability with other
241 sites and is not currently recommended. Lowering this will permit you to
242 establish a TLS session which is not as secure as you might like.
244 Unless you really know what you are doing, leave it alone.
246 4. If not built with DISABLE_DNSSEC, Exim now has the main option
247 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
248 to send the DO flag to your recursive resolver. If you have a recursive
249 resolver, which can set the Authenticated Data (AD) flag in results, Exim
250 can now detect this. Exim does not perform validation itself, instead
251 relying upon a trusted path to the resolver.
253 Current status: work-in-progress; $sender_host_dnssec variable added.
255 5. DSCP support for outbound connections: on a transport using the smtp driver,
256 set "dscp = ef", for instance, to cause the connections to have the relevant
257 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
259 Similarly for inbound connections, there is a new control modifier, dscp,
260 so "warn control = dscp/ef" in the connect ACL, or after authentication.
262 Supported values depend upon system libraries. "exim -bI:dscp" to list the
263 ones Exim knows of. You can also set a raw number 0..0x3F.
265 6. The -G command-line flag is no longer ignored; it is now equivalent to an
266 ACL setting "control = suppress_local_fixups". The -L command-line flag
267 is now accepted and forces use of syslog, with the provided tag as the
268 process name. A few other flags used by Sendmail are now accepted and
271 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
272 ACL modifier; works for single-recipient mails which are received on and
273 deliverable via SMTP. Using the connection made for a recipient verify,
274 if requested before the verify, or a new one made for the purpose while
275 the inbound connection is still active. The bulk of the mail item is copied
276 direct from the inbound socket to the outbound (as well as the spool file).
277 When the source notifies the end of data, the data acceptance by the destination
278 is negotiated before the acceptance is sent to the source. If the destination
279 does not accept the mail item, for example due to content-scanning, the item
280 is not accepted from the source and therefore there is no need to generate
281 a bounce mail. This is of benefit when providing a secondary-MX service.
282 The downside is that delays are under the control of the ultimate destination
285 The Received-by: header on items delivered by cutthrough is generated
286 early in reception rather than at the end; this will affect any timestamp
287 included. The log line showing delivery is recorded before that showing
288 reception; it uses a new ">>" tag instead of "=>".
290 To support the feature, verify-callout connections can now use ESMTP and TLS.
291 The usual smtp transport options are honoured, plus a (new, default everything)
292 hosts_verify_avoid_tls.
294 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
295 for specific access to the information for each connection. The old names
296 are present for now but deprecated.
298 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
300 8. New expansion operators ${listnamed:name} to get the content of a named list
301 and ${listcount:string} to count the items in a list.
303 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
304 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
305 modules. For some situations this is desirable, but we expect admin in
306 those situations to know they want the feature. More commonly, it means
307 that GUI user modules get loaded and are broken by the setuid Exim being
308 unable to access files specified in environment variables and passed
309 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
310 unless this new option is set.
312 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
313 so have also added a build option which can be used to build Exim with GnuTLS
314 but without trying to use any kind of PKCS11 support. Uncomment this in the
317 AVOID_GNUTLS_PKCS11=yes
319 10. The "acl = name" condition on an ACL now supports optional arguments.
320 New expansion item "${acl {name}{arg}...}" and expansion condition
321 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
322 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
323 Variable $acl_narg contains the number of arguments. If the ACL sets
324 a "message =" value this becomes the result of the expansion item,
325 or the value of $value for the expansion condition. If the ACL returns
326 accept the expansion condition is true; if reject, false. A defer
327 return results in a forced fail.
329 11. Routers and transports can now have multiple headers_add and headers_remove
330 option lines. The concatenated list is used.
332 12. New ACL modifier "remove_header" can remove headers before message gets
333 handled by routers/transports.
335 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
336 "aaaa" and "a" lookups is done and the full set of results returned.
338 14. New expansion variable $headers_added with content from ACL add_header
339 modifier (but not yet added to message).
341 15. New 8bitmime status logging option for received messages. Log field "M8S".
343 16. New authenticated_sender logging option, adding to log field "A".
345 17. New expansion variables $router_name and $transport_name. Useful
346 particularly for debug_print as -bt command-line option does not
347 require privilege whereas -d does.
349 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
350 proposed extension to SMTP from Eric Hall.
352 19. The pipe transport has gained the force_command option, to allow
353 decorating commands from user .forward pipe aliases with prefix
354 wrappers, for instance.
356 20. Callout connections can now AUTH; the same controls as normal delivery
359 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
360 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
361 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
362 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
363 dmarc_status. It adds new control flags dmarc_disable_verify and
364 dmarc_enable_forensic.
366 22. Add expansion variable $authenticated_fail_id, which is the username
367 provided to the authentication method which failed. It is available
368 for use in subsequent ACL processing (typically quit or notquit ACLs).
370 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
373 24. New ${hexquote:..string..} expansion operator converts non-printable
374 characters in the string to \xNN form.
376 25. Experimental TPDA (Transport Post Delivery Action) function added.
377 Patch provided by Axel Rau.
379 26. Experimental Redis lookup added. Patch provided by Warren Baker.
385 1. New authenticator driver, "gsasl". Server-only (at present).
386 This is a SASL interface, licensed under GPL, which can be found at
387 http://www.gnu.org/software/gsasl/.
388 This system does not provide sources of data for authentication, so
389 careful use needs to be made of the conditions in Exim.
391 2. New authenticator driver, "heimdal_gssapi". Server-only.
392 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
393 is no longer honoured for setuid programs by Heimdal. Use the
394 "server_keytab" option to point to the keytab.
396 3. The "pkg-config" system can now be used when building Exim to reference
397 cflags and library information for lookups and authenticators, rather
398 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
399 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
400 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
402 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
403 find the headers and libraries for PCRE.
405 4. New expansion variable $tls_bits.
407 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
408 be joined together with ASCII NUL characters to construct the key to pass
409 into the DBM library. Can be used with gsasl to access sasldb2 files as
412 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
414 Avoid release 1.0.1a if you can. Note that the default value of
415 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
416 increased susceptibility to attack. This may still have interoperability
417 implications for very old clients (see version 4.31 change 37) but
418 administrators can choose to make the trade-off themselves and restore
419 compatibility at the cost of session security.
421 7. Use of the new expansion variable $tls_sni in the main configuration option
422 tls_certificate will cause Exim to re-expand the option, if the client
423 sends the TLS Server Name Indication extension, to permit choosing a
424 different certificate; tls_privatekey will also be re-expanded. You must
425 still set these options to expand to valid files when $tls_sni is not set.
427 The SMTP Transport has gained the option tls_sni, which will set a hostname
428 for outbound TLS sessions, and set $tls_sni too.
430 A new log_selector, +tls_sni, has been added, to log received SNI values
431 for Exim as a server.
433 8. The existing "accept_8bitmime" option now defaults to true. This means
434 that Exim is deliberately not strictly RFC compliant. We're following
435 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
436 Those who disagree, or know that they are talking to mail servers that,
437 even today, are not 8-bit clean, need to turn off this option.
439 9. Exim can now be started with -bw (with an optional timeout, given as
440 -bw<timespec>). With this, stdin at startup is a socket that is
441 already listening for connections. This has a more modern name of
442 "socket activation", but forcing the activated socket to fd 0. We're
443 interested in adding more support for modern variants.
445 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
446 for numbers indicates multiplication by 1024^3.
448 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
449 gnutls_require_mac & gnutls_require_protocols are no longer supported.
450 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
451 string, documentation for which is at:
452 http://www.gnutls.org/manual/html_node/Priority-Strings.html
454 SNI support has been added to Exim's GnuTLS integration too.
456 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
457 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
459 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
460 is now available. If the contents of the file are valid, then Exim will
461 send that back in response to a TLS status request; this is OCSP Stapling.
462 Exim will not maintain the contents of the file in any way: administrators
463 are responsible for ensuring that it is up-to-date.
465 See "experimental-spec.txt" for more details.
467 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
468 identically to TXT record lookups.
470 14. New expansion variable $tod_epoch_l for higher-precision time.
472 15. New global option tls_dh_max_bits, defaulting to current value of NSS
473 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
474 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
476 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
477 Option can now be a path or an identifier for a standard prime.
478 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
479 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
482 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
483 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
484 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
490 1. New options for the ratelimit ACL condition: /count= and /unique=.
491 The /noupdate option has been replaced by a /readonly option.
493 2. The SMTP transport's protocol option may now be set to "smtps", to
494 use SSL-on-connect outbound.
496 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
497 there is a problem talking to the AV scanner, or the AV scanner running.
499 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
500 and check if the search item is a member of the list. This does not
501 support named lists, but does subject the list part to string expansion.
503 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
504 built, Exim no longer performs string expansion on the second string of
505 the match_* expansion conditions: "match_address", "match_domain",
506 "match_ip" & "match_local_part". Named lists can still be used.
512 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
513 or off in the resolver library.
519 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
520 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
521 libraries. The following global options have been added in support of
522 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
523 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
525 2. The pipe transport now takes a boolean option, "freeze_signal", default
526 false. When true, if the external delivery command exits on a signal then
527 Exim will freeze the message in the queue, instead of generating a bounce.
529 3. Log filenames may now use %M as an escape, instead of %D (still available).
530 The %M pattern expands to yyyymm, providing month-level resolution.
532 4. The $message_linecount variable is now updated for the maildir_tag option,
533 in the same way as $message_size, to reflect the real number of lines,
534 including any header additions or removals from transport.
536 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
537 Exim now selects entries randomly, to better scale in a cluster setup.
543 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
544 the flaw permitted the Exim run-time user to cause root to append to
545 arbitrary files of the attacker's choosing, with the content based
546 on content supplied by the attacker.
548 2. Exim now supports loading some lookup types at run-time, using your
549 platform's dlopen() functionality. This has limited platform support
550 and the intention is not to support every variant, it's limited to
551 dlopen(). This permits the main Exim binary to not be linked against
552 all the libraries needed for all the lookup types.
558 NOTE: this version is not guaranteed backwards-compatible, please read the
559 items below carefully
561 1. A new main configuration option, "openssl_options", is available if Exim
562 is built with SSL support provided by OpenSSL. The option allows
563 administrators to specify OpenSSL options to be used on connections;
564 typically this is to set bug compatibility features which the OpenSSL
565 developers have not enabled by default. There may be security
566 consequences for certain options, so these should not be changed
569 2. A new pipe transport option, "permit_coredumps", may help with problem
570 diagnosis in some scenarios. Note that Exim is typically installed as
571 a setuid binary, which on most OSes will inhibit coredumps by default,
572 so that safety mechanism would have to be overridden for this option to
573 be able to take effect.
575 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
576 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
577 Note that this switches Exim to use a new API ("INSTREAM") and a future
578 release of ClamAV will remove support for the old API ("STREAM").
580 The av_scanner option, when set to "clamd", now takes an optional third
581 part, "local", which causes Exim to pass a filename to ClamAV instead of
582 the file content. This is the same behaviour as when clamd is pointed at
583 a Unix-domain socket. For example:
585 av_scanner = clamd:192.0.2.3 1234:local
587 ClamAV's ExtendedDetectionInfo response format is now handled.
589 4. There is now a -bmalware option, restricted to admin users. This option
590 takes one parameter, a filename, and scans that file with Exim's
591 malware-scanning framework. This is intended purely as a debugging aid
592 to ensure that Exim's scanning is working, not to replace other tools.
593 Note that the ACL framework is not invoked, so if av_scanner references
594 ACL variables without a fallback then this will fail.
596 5. There is a new expansion operator, "reverse_ip", which will reverse IP
597 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
599 ${reverse_ip:192.0.2.4}
601 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
602 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
604 6. There is a new ACL control called "debug", to enable debug logging.
605 This allows selective logging of certain incoming transactions within
606 production environments, with some care. It takes two options, "tag"
607 and "opts"; "tag" is included in the filename of the log and "opts"
608 is used as per the -d<options> command-line option. Examples, which
609 don't all make sense in all contexts:
612 control = debug/tag=.$sender_host_address
613 control = debug/opts=+expand+acl
614 control = debug/tag=.$message_exim_id/opts=+expand
616 7. It has always been implicit in the design and the documentation that
617 "the Exim user" is not root. src/EDITME said that using root was
618 "very strongly discouraged". This is not enough to keep people from
619 shooting themselves in the foot in days when many don't configure Exim
620 themselves but via package build managers. The security consequences of
621 running various bits of network code are severe if there should be bugs in
622 them. As such, the Exim user may no longer be root. If configured
623 statically, Exim will refuse to build. If configured as ref:user then Exim
624 will exit shortly after start-up. If you must shoot yourself in the foot,
625 then henceforth you will have to maintain your own local patches to strip
628 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
629 condition logic to determine truth/failure and will fail to expand many
630 strings, bool_lax{} uses the router condition logic, where most strings
632 Note: bool{00} is false, bool_lax{00} is true.
634 9. Routers now support multiple "condition" tests.
636 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
637 Setting this allows an admin to define which entry in the tcpwrappers
638 config file will be used to control access to the daemon. This option
639 is only available when Exim is built with USE_TCP_WRAPPERS. The
640 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
643 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
644 the Exim run-time user, instead of root.
646 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
647 is forced on. This is mitigated by the new build option
648 TRUSTED_CONFIG_LIST which defines a list of configuration files which
649 are trusted; one per line. If a config file is owned by root and matches
650 a pathname in the list, then it may be invoked by the Exim build-time
651 user without Exim relinquishing root privileges.
653 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
654 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
655 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
656 include the main config. As a transition mechanism, we are temporarily
657 providing a work-around: the new build option WHITELIST_D_MACROS provides
658 a colon-separated list of macro names which may be overridden by the Exim
659 run-time user. The values of these macros are constrained to the regex
660 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
666 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
667 writable, the other to locking of MBX folders (not mbox).
669 2. MySQL stored procedures are now supported.
671 3. The dkim_domain transport option is now a list, not a single string, and
672 messages will be signed for each element in the list (discarding
675 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
676 in the presence of multiple character strings within the RR. Prior to 4.70,
677 only the first string would be returned. The dnsdb lookup now, by default,
678 preserves the pre-4.70 semantics, but also now takes an extended output
679 separator specification. The separator can be followed by a semicolon, to
680 concatenate the individual text strings together with no join character,
681 or by a comma and a second separator character, in which case the text
682 strings within a TXT record are joined on that second character.
683 Administrators are reminded that DNS provides no ordering guarantees
684 between multiple records in an RRset. For example:
686 foo.example. IN TXT "a" "b" "c"
687 foo.example. IN TXT "d" "e" "f"
689 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
690 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
691 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
697 1. Native DKIM support without an external library.
698 (Note that if no action to prevent it is taken, a straight upgrade will
699 result in DKIM verification of all signed incoming emails. See spec
700 for details on conditionally disabling)
702 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
704 3. There is now a bool{} expansion condition which maps certain strings to
705 true/false condition values (most likely of use in conjunction with the
706 and{} expansion operator).
708 4. The $spam_score, $spam_bar and $spam_report variables are now available
711 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
712 options, provided that Exim is invoked by an admin_user.
714 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
715 which increases compatibility with older clients at the cost of decreased
716 security. Don't set this unless you need to support such clients.
718 7. There is a new expansion operator, ${randint:...} which will produce a
719 "random" number less than the supplied integer. This randomness is
720 not guaranteed to be cryptographically strong, but depending upon how
721 Exim was built may be better than the most naive schemes.
723 8. Exim now explicitly ensures that SHA256 is available when linked against
726 9. The transport_filter_timeout option now applies to SMTP transports too.
732 1. Preliminary DKIM support in Experimental.
738 1. The body_linecount and body_zerocount C variables are now exported in the
741 2. When a dnslists lookup succeeds, the key that was looked up is now placed
742 in $dnslist_matched. When the key is an IP address, it is not reversed in
743 this variable (though it is, of course, in the actual lookup). In simple
746 deny dnslists = spamhaus.example
748 the key is also available in another variable (in this case,
749 $sender_host_address). In more complicated cases, however, this is not
750 true. For example, using a data lookup might generate a dnslists lookup
753 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
755 If this condition succeeds, the value in $dnslist_matched might be
756 192.168.6.7 (for example).
758 3. Authenticators now have a client_condition option. When Exim is running as
759 a client, it skips an authenticator whose client_condition expansion yields
760 "0", "no", or "false". This can be used, for example, to skip plain text
761 authenticators when the connection is not encrypted by a setting such as:
763 client_condition = ${if !eq{$tls_cipher}{}}
765 Note that the 4.67 documentation states that $tls_cipher contains the
766 cipher used for incoming messages. In fact, during SMTP delivery, it
767 contains the cipher used for the delivery. The same is true for
770 4. There is now a -Mvc <message-id> option, which outputs a copy of the
771 message to the standard output, in RFC 2822 format. The option can be used
772 only by an admin user.
774 5. There is now a /noupdate option for the ratelimit ACL condition. It
775 computes the rate and checks the limit as normal, but it does not update
776 the saved data. This means that, in relevant ACLs, it is possible to lookup
777 the existence of a specified (or auto-generated) ratelimit key without
778 incrementing the ratelimit counter for that key.
780 In order for this to be useful, another ACL entry must set the rate
781 for the same key somewhere (otherwise it will always be zero).
786 # Read the rate; if it doesn't exist or is below the maximum
788 deny ratelimit = 100 / 5m / strict / noupdate
789 log_message = RATE: $sender_rate / $sender_rate_period \
790 (max $sender_rate_limit)
792 [... some other logic and tests...]
794 warn ratelimit = 100 / 5m / strict / per_cmd
795 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
796 (max $sender_rate_limit)
797 condition = ${if le{$sender_rate}{$sender_rate_limit}}
801 6. The variable $max_received_linelength contains the number of bytes in the
802 longest line that was received as part of the message, not counting the
803 line termination character(s).
805 7. Host lists can now include +ignore_defer and +include_defer, analagous to
806 +ignore_unknown and +include_unknown. These options should be used with
807 care, probably only in non-critical host lists such as whitelists.
809 8. There's a new option called queue_only_load_latch, which defaults true.
810 If set false when queue_only_load is greater than zero, Exim re-evaluates
811 the load for each incoming message in an SMTP session. Otherwise, once one
812 message is queued, the remainder are also.
814 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
815 cases when an SMTP session ends without sending QUIT. However, when Exim
816 itself is is bad trouble, such as being unable to write to its log files,
817 this ACL is not run, because it might try to do things (such as write to
818 log files) that make the situation even worse.
820 Like the QUIT ACL, this new ACL is provided to make it possible to gather
821 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
822 modifier is forbidden in this ACL.
824 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
825 to a string that indicates the reason for the termination of the SMTP
826 connection. The possible values are:
828 acl-drop Another ACL issued a "drop" command
829 bad-commands Too many unknown or non-mail commands
830 command-timeout Timeout while reading SMTP commands
831 connection-lost The SMTP connection has been lost
832 data-timeout Timeout while reading message data
833 local-scan-error The local_scan() function crashed
834 local-scan-timeout The local_scan() function timed out
835 signal-exit SIGTERM or SIGINT
836 synchronization-error SMTP synchronization error
837 tls-failed TLS failed to start
839 In most cases when an SMTP connection is closed without having received
840 QUIT, Exim sends an SMTP response message before actually closing the
841 connection. With the exception of acl-drop, the default message can be
842 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
843 "drop" verb in another ACL, it is the message from the other ACL that is
846 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
847 servers with individual queries. This is done by starting the query with
848 "servers=x:y:z;", where each item in the list may take one of two forms:
850 (1) If it is just a host name, the appropriate global option (mysql_servers
851 or pgsql_servers) is searched for a host of the same name, and the
852 remaining parameters (database, user, password) are taken from there.
854 (2) If it contains any slashes, it is taken as a complete parameter set.
856 The list of servers is used in exactly the same was as the global list.
857 Once a connection to a server has happened and a query has been
858 successfully executed, processing of the lookup ceases.
860 This feature is intended for use in master/slave situations where updates
861 are occurring, and one wants to update a master rather than a slave. If the
862 masters are in the list for reading, you might have:
864 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
866 In an updating lookup, you could then write
868 ${lookup mysql{servers=master; UPDATE ...}
870 If, on the other hand, the master is not to be used for reading lookups:
872 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
874 you can still update the master by
876 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
878 11. The message_body_newlines option (default FALSE, for backwards
879 compatibility) can be used to control whether newlines are present in
880 $message_body and $message_body_end. If it is FALSE, they are replaced by
887 1. There is a new log selector called smtp_no_mail, which is not included in
888 the default setting. When it is set, a line is written to the main log
889 whenever an accepted SMTP connection terminates without having issued a
892 2. When an item in a dnslists list is followed by = and & and a list of IP
893 addresses, the behaviour was not clear when the lookup returned more than
894 one IP address. This has been solved by the addition of == and =& for "all"
895 rather than the default "any" matching.
897 3. Up till now, the only control over which cipher suites GnuTLS uses has been
898 for the cipher algorithms. New options have been added to allow some of the
899 other parameters to be varied.
901 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
902 set, Exim compiles a runtime option called disable_fsync.
904 5. There is a new variable called $smtp_count_at_connection_start.
906 6. There's a new control called no_pipelining.
908 7. There are two new variables called $sending_ip_address and $sending_port.
909 These are set whenever an SMTP connection to another host has been set up.
911 8. The expansion of the helo_data option in the smtp transport now happens
912 after the connection to the server has been made.
914 9. There is a new expansion operator ${rfc2047d: that decodes strings that
915 are encoded as per RFC 2047.
917 10. There is a new log selector called "pid", which causes the current process
918 id to be added to every log line, in square brackets, immediately after the
921 11. Exim has been modified so that it flushes SMTP output before implementing
922 a delay in an ACL. It also flushes the output before performing a callout,
923 as this can take a substantial time. These behaviours can be disabled by
924 obeying control = no_delay_flush or control = no_callout_flush,
925 respectively, at some earlier stage of the connection.
927 12. There are two new expansion conditions that iterate over a list. They are
928 called forany and forall.
930 13. There's a new global option called dsn_from that can be used to vary the
931 contents of From: lines in bounces and other automatically generated
932 messages ("delivery status notifications" - hence the name of the option).
934 14. The smtp transport has a new option called hosts_avoid_pipelining.
936 15. By default, exigrep does case-insensitive matches. There is now a -I option
937 that makes it case-sensitive.
939 16. A number of new features ("addresses", "map", "filter", and "reduce") have
940 been added to string expansions to make it easier to process lists of
941 items, typically addresses.
943 17. There's a new ACL modifier called "continue". It does nothing of itself,
944 and processing of the ACL always continues with the next condition or
945 modifier. It is provided so that the side effects of expanding its argument
948 18. It is now possible to use newline and other control characters (those with
949 values less than 32, plus DEL) as separators in lists.
951 19. The exigrep utility now has a -v option, which inverts the matching
954 20. The host_find_failed option in the manualroute router can now be set to
961 No new features were added to 4.66.
967 No new features were added to 4.65.
973 1. ACL variables can now be given arbitrary names, as long as they start with
974 "acl_c" or "acl_m" (for connection variables and message variables), are at
975 least six characters long, with the sixth character being either a digit or
978 2. There is a new ACL modifier called log_reject_target. It makes it possible
979 to specify which logs are used for messages about ACL rejections.
981 3. There is a new authenticator called "dovecot". This is an interface to the
982 authentication facility of the Dovecot POP/IMAP server, which can support a
983 number of authentication methods.
985 4. The variable $message_headers_raw provides a concatenation of all the
986 messages's headers without any decoding. This is in contrast to
987 $message_headers, which does RFC2047 decoding on the header contents.
989 5. In a DNS black list, if two domain names, comma-separated, are given, the
990 second is used first to do an initial check, making use of any IP value
991 restrictions that are set. If there is a match, the first domain is used,
992 without any IP value restrictions, to get the TXT record.
994 6. All authenticators now have a server_condition option.
996 7. There is a new command-line option called -Mset. It is useful only in
997 conjunction with -be (that is, when testing string expansions). It must be
998 followed by a message id; Exim loads the given message from its spool
999 before doing the expansions.
1001 8. Another similar new command-line option is called -bem. It operates like
1002 -be except that it must be followed by the name of a file that contains a
1005 9. When an address is delayed because of a 4xx response to a RCPT command, it
1006 is now the combination of sender and recipient that is delayed in
1007 subsequent queue runs until its retry time is reached.
1009 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1010 shift, have been added to the eval: and eval10: expansion items.
1012 11. The variables $interface_address and $interface_port have been renamed
1013 as $received_ip_address and $received_port, to make it clear that they
1014 relate to message reception rather than delivery. (The old names remain
1015 available for compatibility.)
1017 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1018 to vary the message that is sent when an SMTP command is accepted.
1024 1. There is a new Boolean option called filter_prepend_home for the redirect
1027 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1028 start of receiving a non-SMTP message, before any of the message has been
1031 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1032 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1033 start of the message for an SMTP error code.
1035 4. There is a new parameter for LDAP lookups called "referrals", which takes
1036 one of the settings "follow" (the default) or "nofollow".
1038 5. Version 20070721.2 of exipick now included, offering these new options:
1040 After all other sorting options have bee processed, reverse order
1041 before displaying messages (-R is synonym).
1043 Randomize order of matching messages before displaying.
1045 Instead of displaying the matching messages, display the sum
1047 --sort <variable>[,<variable>...]
1048 Before displaying matching messages, sort the messages according to
1049 each messages value for each variable.
1051 Negate the value for every test (returns inverse output from the
1052 same criteria without --not).
1058 1. The ${readsocket expansion item now supports Internet domain sockets as well
1059 as Unix domain sockets. If the first argument begins "inet:", it must be of
1060 the form "inet:host:port". The port is mandatory; it may be a number or the
1061 name of a TCP port in /etc/services. The host may be a name, or it may be an
1062 IP address. An ip address may optionally be enclosed in square brackets.
1063 This is best for IPv6 addresses. For example:
1065 ${readsocket{inet:[::1]:1234}{<request data>}...
1067 Only a single host name may be given, but if looking it up yield more than
1068 one IP address, they are each tried in turn until a connection is made. Once
1069 a connection has been made, the behaviour is as for ${readsocket with a Unix
1072 2. If a redirect router sets up file or pipe deliveries for more than one
1073 incoming address, and the relevant transport has batch_max set greater than
1074 one, a batch delivery now occurs.
1076 3. The appendfile transport has a new option called maildirfolder_create_regex.
1077 Its value is a regular expression. For a maildir delivery, this is matched
1078 against the maildir directory; if it matches, Exim ensures that a
1079 maildirfolder file is created alongside the new, cur, and tmp directories.
1085 The documentation is up-to-date for the 4.61 release. Major new features since
1086 the 4.60 release are:
1088 . An option called disable_ipv6, to disable the use of IPv6 completely.
1090 . An increase in the number of ACL variables to 20 of each type.
1092 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1093 $2, $3, (though those are still set) because the numeric variables get used
1094 for other things in complicated expansions.
1096 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1098 . It is possible to use setclassresources() on some BSD OS to control the
1099 resources used in pipe deliveries.
1101 . A new ACL modifier called add_header, which can be used with any verb.
1103 . More errors are detectable in retry rules.
1105 There are a number of other additions too.
1111 The documentation is up-to-date for the 4.60 release. Major new features since
1112 the 4.50 release are:
1114 . Support for SQLite.
1116 . Support for IGNOREQUOTA in LMTP.
1118 . Extensions to the "submission mode" features.
1120 . Support for Client SMTP Authorization (CSA).
1122 . Support for ratelimiting hosts and users.
1124 . New expansion items to help with the BATV "prvs" scheme.
1126 . A "match_ip" condition, that matches an IP address against a list.
1128 There are many more minor changes.
git://git.exim.org / exim.git / blob