4 This file contains descriptions of new features that have been added to Exim.
5 Before a formal release, there may be quite a lot of detail so that people can
6 test from the snapshots or the Git before the documentation is updated. Once
7 the documentation is updated, this file is reduced to a short list.
12 1. PKG_CONFIG_PATH can now be set in Local/Makefile;
13 wildcards will be expanded, values are collapsed.
19 1. Allow relative config file names for ".include"
25 1. The new perl_taintmode option allows to run the embedded perl
26 interpreter in taint mode.
28 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
30 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
33 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
34 N can be 224, 256 (default), 384, 512.
35 With GnuTLS 3.5.0 or later, only.
37 5. Facility for named queues: A command-line argument can specify
38 the queue name for a queue operation, and an ACL modifier can set
39 the queue to be used for a message. A $queue_name variable gives
42 6. New expansion operators base32/base32d.
44 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
45 performance increase and network load decrease. Main config option
46 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
49 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
51 9. Expansion operator escape8bit, like escape but not touching newline etc..
53 10. Feature macros, generated from compile options. All start with "_HAVE_"
54 and go on with some roughly recognisable name. Driver macros, for
55 router, transport and authentication drivers; names starting with "_DRIVER_".
56 Option macros, for each configuration-file option; all start with "_OPT_".
57 Use the "-bP macros" command-line option to see what is present.
59 11. Integer values for options can take a "G" multiplier.
61 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
62 returns from the target back to the initiator, rather than spooling the
65 13. New built-in constants available for tls_dhparam and default changed.
67 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
68 out copies of the message spool files for use by 3rd-party scanners.
70 15. A new option on the smtp transport, hosts_try_fastopen. If the system
71 supports it (on Linux it must be enabled in the kernel by the sysadmin)
72 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
73 but it permits a peer that also supports the facility to send its SMTP
74 banner immediately after the SYN,ACK segment rather then waiting for
75 another ACK - so saving up to one roundtrip time. Because it requires
76 previous communication with the peer (we save a cookie from it) this
77 will only become active on frequently-contacted destinations.
79 16. A new syslog_pid option to suppress PID duplication in syslog lines.
85 1. The ACL conditions regex and mime_regex now capture substrings
86 into numeric variables $regex1 to 9, like the "match" expansion condition.
88 2. New $callout_address variable records the address used for a spam=,
89 malware= or verify= callout.
91 3. Transports now take a "max_parallel" option, to limit concurrency.
93 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
94 The latter expands to a 8-element colon-sep set of hex digits including
95 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
96 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
97 The former operator strips leading zeroes and collapses the longest
98 set of 0-groups to a double-colon.
100 5. New "-bP config" support, to dump the effective configuration.
102 6. New $dkim_key_length variable.
104 7. New base64d and base64 expansion items (the existing str2b64 being a
105 synonym of the latter). Add support in base64 for certificates.
107 8. New main configuration option "bounce_return_linesize_limit" to
108 avoid oversize bodies in bounces. The default value matches RFC
111 9. New $initial_cwd expansion variable.
117 1. Support for using the system standard CA bundle.
119 2. New expansion items $config_file, $config_dir, containing the file
120 and directory name of the main configuration file. Also $exim_version.
122 3. New "malware=" support for Avast.
124 4. New "spam=" variant option for Rspamd.
126 5. Assorted options on malware= and spam= scanners.
128 6. A command-line option to write a comment into the logfile.
130 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
131 be configured to make connections via socks5 proxies.
133 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
134 the transmission of UTF-8 envelope addresses.
136 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
137 used encoding of Maildir folder names.
139 10. A logging option for slow DNS lookups.
141 11. New ${env {<variable>}} expansion.
143 12. A non-SMTP authenticator using information from TLS client certificates.
145 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
146 Patch originally by Wolfgang Breyha.
148 14. Main option "dns_trust_aa" for trusting your local nameserver at the
149 same level as DNSSEC.
155 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
156 DANE SMTP draft to assess a secure chain of trust of the certificate
157 used to establish the TLS connection based on a TLSA record in the
158 domain of the sender.
160 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
161 and several new events have been created. The reason is because it has
162 been expanded beyond just firing events during the transport phase. Any
163 existing TPDA transport options will have to be rewritten to use a new
164 $event_name expansion variable in a condition. Refer to the
165 experimental-spec.txt for details and examples.
167 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
168 server certs used for TLS match the result of the MX lookup. It does
169 not use the same mechanism as DANE.
179 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
180 configured to expect an initial header from a proxy that will make the
181 actual external source IP:host be used in exim instead of the IP of the
182 proxy that is connecting to it.
184 2. New verify option header_names_ascii, which will check to make sure
185 there are no non-ASCII characters in header names. Exim itself handles
186 those non-ASCII characters, but downstream apps may not, so Exim can
187 detect and reject if those characters are present.
189 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
190 codepoints with valid ones.
192 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
193 command line and matching a regex against the return data for trigger
194 and a second regex to extract malware_name. The mail spoolfile name can
195 be included in the command line.
197 5. The smtp transport now supports options "tls_verify_hosts" and
198 "tls_try_verify_hosts". If either is set the certificate verification
199 is split from the encryption operation. The default remains that a failed
200 verification cancels the encryption.
202 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
203 lookup can now set a list of servers to use that is different from the
206 7. New command-line option -C for exiqgrep to specify alternate exim.conf
207 file when searching the queue.
209 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
211 9. Support for DNSSEC on outbound connections.
213 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
214 "certextract" to extract fields from them. Hash operators md5 and sha1
215 work over them for generating fingerprints, and a new sha256 operator
218 11. PRDR is now supported dy default.
220 12. OCSP stapling is now supported by default.
222 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
223 Delivery Status Notification messages in MIME format, and negotiate
224 DSN features per RFC 3461.
230 1. New command-line option -bI:sieve will list all supported sieve extensions
231 of this Exim build on standard output, one per line.
232 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
233 query this to establish the correct list to include in the protocol's
234 SIEVE capability line.
236 2. If the -n option is combined with the -bP option, then the name of an
237 emitted option is not output, only the value (if visible to you).
238 For instance, "exim -n -bP pid_file_path" should just emit a pathname
239 followed by a newline, and no other text.
241 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
242 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
243 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
244 acceptable for security. (Option accepted but ignored if using OpenSSL).
245 Defaults to 1024, the old value. May be lowered only to 512, or raised as
246 far as you like. Raising this may hinder TLS interoperability with other
247 sites and is not currently recommended. Lowering this will permit you to
248 establish a TLS session which is not as secure as you might like.
250 Unless you really know what you are doing, leave it alone.
252 4. If not built with DISABLE_DNSSEC, Exim now has the main option
253 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
254 to send the DO flag to your recursive resolver. If you have a recursive
255 resolver, which can set the Authenticated Data (AD) flag in results, Exim
256 can now detect this. Exim does not perform validation itself, instead
257 relying upon a trusted path to the resolver.
259 Current status: work-in-progress; $sender_host_dnssec variable added.
261 5. DSCP support for outbound connections: on a transport using the smtp driver,
262 set "dscp = ef", for instance, to cause the connections to have the relevant
263 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
265 Similarly for inbound connections, there is a new control modifier, dscp,
266 so "warn control = dscp/ef" in the connect ACL, or after authentication.
268 Supported values depend upon system libraries. "exim -bI:dscp" to list the
269 ones Exim knows of. You can also set a raw number 0..0x3F.
271 6. The -G command-line flag is no longer ignored; it is now equivalent to an
272 ACL setting "control = suppress_local_fixups". The -L command-line flag
273 is now accepted and forces use of syslog, with the provided tag as the
274 process name. A few other flags used by Sendmail are now accepted and
277 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
278 ACL modifier; works for single-recipient mails which are received on and
279 deliverable via SMTP. Using the connection made for a recipient verify,
280 if requested before the verify, or a new one made for the purpose while
281 the inbound connection is still active. The bulk of the mail item is copied
282 direct from the inbound socket to the outbound (as well as the spool file).
283 When the source notifies the end of data, the data acceptance by the destination
284 is negotiated before the acceptance is sent to the source. If the destination
285 does not accept the mail item, for example due to content-scanning, the item
286 is not accepted from the source and therefore there is no need to generate
287 a bounce mail. This is of benefit when providing a secondary-MX service.
288 The downside is that delays are under the control of the ultimate destination
291 The Received-by: header on items delivered by cutthrough is generated
292 early in reception rather than at the end; this will affect any timestamp
293 included. The log line showing delivery is recorded before that showing
294 reception; it uses a new ">>" tag instead of "=>".
296 To support the feature, verify-callout connections can now use ESMTP and TLS.
297 The usual smtp transport options are honoured, plus a (new, default everything)
298 hosts_verify_avoid_tls.
300 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
301 for specific access to the information for each connection. The old names
302 are present for now but deprecated.
304 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
306 8. New expansion operators ${listnamed:name} to get the content of a named list
307 and ${listcount:string} to count the items in a list.
309 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
310 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
311 modules. For some situations this is desirable, but we expect admin in
312 those situations to know they want the feature. More commonly, it means
313 that GUI user modules get loaded and are broken by the setuid Exim being
314 unable to access files specified in environment variables and passed
315 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
316 unless this new option is set.
318 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
319 so have also added a build option which can be used to build Exim with GnuTLS
320 but without trying to use any kind of PKCS11 support. Uncomment this in the
323 AVOID_GNUTLS_PKCS11=yes
325 10. The "acl = name" condition on an ACL now supports optional arguments.
326 New expansion item "${acl {name}{arg}...}" and expansion condition
327 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
328 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
329 Variable $acl_narg contains the number of arguments. If the ACL sets
330 a "message =" value this becomes the result of the expansion item,
331 or the value of $value for the expansion condition. If the ACL returns
332 accept the expansion condition is true; if reject, false. A defer
333 return results in a forced fail.
335 11. Routers and transports can now have multiple headers_add and headers_remove
336 option lines. The concatenated list is used.
338 12. New ACL modifier "remove_header" can remove headers before message gets
339 handled by routers/transports.
341 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
342 "aaaa" and "a" lookups is done and the full set of results returned.
344 14. New expansion variable $headers_added with content from ACL add_header
345 modifier (but not yet added to message).
347 15. New 8bitmime status logging option for received messages. Log field "M8S".
349 16. New authenticated_sender logging option, adding to log field "A".
351 17. New expansion variables $router_name and $transport_name. Useful
352 particularly for debug_print as -bt command-line option does not
353 require privilege whereas -d does.
355 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
356 proposed extension to SMTP from Eric Hall.
358 19. The pipe transport has gained the force_command option, to allow
359 decorating commands from user .forward pipe aliases with prefix
360 wrappers, for instance.
362 20. Callout connections can now AUTH; the same controls as normal delivery
365 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
366 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
367 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
368 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
369 dmarc_status. It adds new control flags dmarc_disable_verify and
370 dmarc_enable_forensic.
372 22. Add expansion variable $authenticated_fail_id, which is the username
373 provided to the authentication method which failed. It is available
374 for use in subsequent ACL processing (typically quit or notquit ACLs).
376 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
379 24. New ${hexquote:..string..} expansion operator converts non-printable
380 characters in the string to \xNN form.
382 25. Experimental TPDA (Transport Post Delivery Action) function added.
383 Patch provided by Axel Rau.
385 26. Experimental Redis lookup added. Patch provided by Warren Baker.
391 1. New authenticator driver, "gsasl". Server-only (at present).
392 This is a SASL interface, licensed under GPL, which can be found at
393 http://www.gnu.org/software/gsasl/.
394 This system does not provide sources of data for authentication, so
395 careful use needs to be made of the conditions in Exim.
397 2. New authenticator driver, "heimdal_gssapi". Server-only.
398 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
399 is no longer honoured for setuid programs by Heimdal. Use the
400 "server_keytab" option to point to the keytab.
402 3. The "pkg-config" system can now be used when building Exim to reference
403 cflags and library information for lookups and authenticators, rather
404 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
405 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
406 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
408 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
409 find the headers and libraries for PCRE.
411 4. New expansion variable $tls_bits.
413 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
414 be joined together with ASCII NUL characters to construct the key to pass
415 into the DBM library. Can be used with gsasl to access sasldb2 files as
418 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
420 Avoid release 1.0.1a if you can. Note that the default value of
421 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
422 increased susceptibility to attack. This may still have interoperability
423 implications for very old clients (see version 4.31 change 37) but
424 administrators can choose to make the trade-off themselves and restore
425 compatibility at the cost of session security.
427 7. Use of the new expansion variable $tls_sni in the main configuration option
428 tls_certificate will cause Exim to re-expand the option, if the client
429 sends the TLS Server Name Indication extension, to permit choosing a
430 different certificate; tls_privatekey will also be re-expanded. You must
431 still set these options to expand to valid files when $tls_sni is not set.
433 The SMTP Transport has gained the option tls_sni, which will set a hostname
434 for outbound TLS sessions, and set $tls_sni too.
436 A new log_selector, +tls_sni, has been added, to log received SNI values
437 for Exim as a server.
439 8. The existing "accept_8bitmime" option now defaults to true. This means
440 that Exim is deliberately not strictly RFC compliant. We're following
441 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
442 Those who disagree, or know that they are talking to mail servers that,
443 even today, are not 8-bit clean, need to turn off this option.
445 9. Exim can now be started with -bw (with an optional timeout, given as
446 -bw<timespec>). With this, stdin at startup is a socket that is
447 already listening for connections. This has a more modern name of
448 "socket activation", but forcing the activated socket to fd 0. We're
449 interested in adding more support for modern variants.
451 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
452 for numbers indicates multiplication by 1024^3.
454 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
455 gnutls_require_mac & gnutls_require_protocols are no longer supported.
456 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
457 string, documentation for which is at:
458 http://www.gnutls.org/manual/html_node/Priority-Strings.html
460 SNI support has been added to Exim's GnuTLS integration too.
462 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
463 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
465 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
466 is now available. If the contents of the file are valid, then Exim will
467 send that back in response to a TLS status request; this is OCSP Stapling.
468 Exim will not maintain the contents of the file in any way: administrators
469 are responsible for ensuring that it is up-to-date.
471 See "experimental-spec.txt" for more details.
473 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
474 identically to TXT record lookups.
476 14. New expansion variable $tod_epoch_l for higher-precision time.
478 15. New global option tls_dh_max_bits, defaulting to current value of NSS
479 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
480 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
482 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
483 Option can now be a path or an identifier for a standard prime.
484 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
485 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
488 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
489 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
490 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
496 1. New options for the ratelimit ACL condition: /count= and /unique=.
497 The /noupdate option has been replaced by a /readonly option.
499 2. The SMTP transport's protocol option may now be set to "smtps", to
500 use SSL-on-connect outbound.
502 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
503 there is a problem talking to the AV scanner, or the AV scanner running.
505 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
506 and check if the search item is a member of the list. This does not
507 support named lists, but does subject the list part to string expansion.
509 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
510 built, Exim no longer performs string expansion on the second string of
511 the match_* expansion conditions: "match_address", "match_domain",
512 "match_ip" & "match_local_part". Named lists can still be used.
518 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
519 or off in the resolver library.
525 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
526 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
527 libraries. The following global options have been added in support of
528 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
529 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
531 2. The pipe transport now takes a boolean option, "freeze_signal", default
532 false. When true, if the external delivery command exits on a signal then
533 Exim will freeze the message in the queue, instead of generating a bounce.
535 3. Log filenames may now use %M as an escape, instead of %D (still available).
536 The %M pattern expands to yyyymm, providing month-level resolution.
538 4. The $message_linecount variable is now updated for the maildir_tag option,
539 in the same way as $message_size, to reflect the real number of lines,
540 including any header additions or removals from transport.
542 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
543 Exim now selects entries randomly, to better scale in a cluster setup.
549 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
550 the flaw permitted the Exim run-time user to cause root to append to
551 arbitrary files of the attacker's choosing, with the content based
552 on content supplied by the attacker.
554 2. Exim now supports loading some lookup types at run-time, using your
555 platform's dlopen() functionality. This has limited platform support
556 and the intention is not to support every variant, it's limited to
557 dlopen(). This permits the main Exim binary to not be linked against
558 all the libraries needed for all the lookup types.
564 NOTE: this version is not guaranteed backwards-compatible, please read the
565 items below carefully
567 1. A new main configuration option, "openssl_options", is available if Exim
568 is built with SSL support provided by OpenSSL. The option allows
569 administrators to specify OpenSSL options to be used on connections;
570 typically this is to set bug compatibility features which the OpenSSL
571 developers have not enabled by default. There may be security
572 consequences for certain options, so these should not be changed
575 2. A new pipe transport option, "permit_coredumps", may help with problem
576 diagnosis in some scenarios. Note that Exim is typically installed as
577 a setuid binary, which on most OSes will inhibit coredumps by default,
578 so that safety mechanism would have to be overridden for this option to
579 be able to take effect.
581 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
582 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
583 Note that this switches Exim to use a new API ("INSTREAM") and a future
584 release of ClamAV will remove support for the old API ("STREAM").
586 The av_scanner option, when set to "clamd", now takes an optional third
587 part, "local", which causes Exim to pass a filename to ClamAV instead of
588 the file content. This is the same behaviour as when clamd is pointed at
589 a Unix-domain socket. For example:
591 av_scanner = clamd:192.0.2.3 1234:local
593 ClamAV's ExtendedDetectionInfo response format is now handled.
595 4. There is now a -bmalware option, restricted to admin users. This option
596 takes one parameter, a filename, and scans that file with Exim's
597 malware-scanning framework. This is intended purely as a debugging aid
598 to ensure that Exim's scanning is working, not to replace other tools.
599 Note that the ACL framework is not invoked, so if av_scanner references
600 ACL variables without a fallback then this will fail.
602 5. There is a new expansion operator, "reverse_ip", which will reverse IP
603 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
605 ${reverse_ip:192.0.2.4}
607 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
608 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
610 6. There is a new ACL control called "debug", to enable debug logging.
611 This allows selective logging of certain incoming transactions within
612 production environments, with some care. It takes two options, "tag"
613 and "opts"; "tag" is included in the filename of the log and "opts"
614 is used as per the -d<options> command-line option. Examples, which
615 don't all make sense in all contexts:
618 control = debug/tag=.$sender_host_address
619 control = debug/opts=+expand+acl
620 control = debug/tag=.$message_exim_id/opts=+expand
622 7. It has always been implicit in the design and the documentation that
623 "the Exim user" is not root. src/EDITME said that using root was
624 "very strongly discouraged". This is not enough to keep people from
625 shooting themselves in the foot in days when many don't configure Exim
626 themselves but via package build managers. The security consequences of
627 running various bits of network code are severe if there should be bugs in
628 them. As such, the Exim user may no longer be root. If configured
629 statically, Exim will refuse to build. If configured as ref:user then Exim
630 will exit shortly after start-up. If you must shoot yourself in the foot,
631 then henceforth you will have to maintain your own local patches to strip
634 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
635 condition logic to determine truth/failure and will fail to expand many
636 strings, bool_lax{} uses the router condition logic, where most strings
638 Note: bool{00} is false, bool_lax{00} is true.
640 9. Routers now support multiple "condition" tests.
642 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
643 Setting this allows an admin to define which entry in the tcpwrappers
644 config file will be used to control access to the daemon. This option
645 is only available when Exim is built with USE_TCP_WRAPPERS. The
646 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
649 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
650 the Exim run-time user, instead of root.
652 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
653 is forced on. This is mitigated by the new build option
654 TRUSTED_CONFIG_LIST which defines a list of configuration files which
655 are trusted; one per line. If a config file is owned by root and matches
656 a pathname in the list, then it may be invoked by the Exim build-time
657 user without Exim relinquishing root privileges.
659 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
660 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
661 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
662 include the main config. As a transition mechanism, we are temporarily
663 providing a work-around: the new build option WHITELIST_D_MACROS provides
664 a colon-separated list of macro names which may be overridden by the Exim
665 run-time user. The values of these macros are constrained to the regex
666 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
672 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
673 writable, the other to locking of MBX folders (not mbox).
675 2. MySQL stored procedures are now supported.
677 3. The dkim_domain transport option is now a list, not a single string, and
678 messages will be signed for each element in the list (discarding
681 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
682 in the presence of multiple character strings within the RR. Prior to 4.70,
683 only the first string would be returned. The dnsdb lookup now, by default,
684 preserves the pre-4.70 semantics, but also now takes an extended output
685 separator specification. The separator can be followed by a semicolon, to
686 concatenate the individual text strings together with no join character,
687 or by a comma and a second separator character, in which case the text
688 strings within a TXT record are joined on that second character.
689 Administrators are reminded that DNS provides no ordering guarantees
690 between multiple records in an RRset. For example:
692 foo.example. IN TXT "a" "b" "c"
693 foo.example. IN TXT "d" "e" "f"
695 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
696 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
697 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
703 1. Native DKIM support without an external library.
704 (Note that if no action to prevent it is taken, a straight upgrade will
705 result in DKIM verification of all signed incoming emails. See spec
706 for details on conditionally disabling)
708 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
710 3. There is now a bool{} expansion condition which maps certain strings to
711 true/false condition values (most likely of use in conjunction with the
712 and{} expansion operator).
714 4. The $spam_score, $spam_bar and $spam_report variables are now available
717 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
718 options, provided that Exim is invoked by an admin_user.
720 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
721 which increases compatibility with older clients at the cost of decreased
722 security. Don't set this unless you need to support such clients.
724 7. There is a new expansion operator, ${randint:...} which will produce a
725 "random" number less than the supplied integer. This randomness is
726 not guaranteed to be cryptographically strong, but depending upon how
727 Exim was built may be better than the most naive schemes.
729 8. Exim now explicitly ensures that SHA256 is available when linked against
732 9. The transport_filter_timeout option now applies to SMTP transports too.
738 1. Preliminary DKIM support in Experimental.
744 1. The body_linecount and body_zerocount C variables are now exported in the
747 2. When a dnslists lookup succeeds, the key that was looked up is now placed
748 in $dnslist_matched. When the key is an IP address, it is not reversed in
749 this variable (though it is, of course, in the actual lookup). In simple
752 deny dnslists = spamhaus.example
754 the key is also available in another variable (in this case,
755 $sender_host_address). In more complicated cases, however, this is not
756 true. For example, using a data lookup might generate a dnslists lookup
759 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
761 If this condition succeeds, the value in $dnslist_matched might be
762 192.168.6.7 (for example).
764 3. Authenticators now have a client_condition option. When Exim is running as
765 a client, it skips an authenticator whose client_condition expansion yields
766 "0", "no", or "false". This can be used, for example, to skip plain text
767 authenticators when the connection is not encrypted by a setting such as:
769 client_condition = ${if !eq{$tls_cipher}{}}
771 Note that the 4.67 documentation states that $tls_cipher contains the
772 cipher used for incoming messages. In fact, during SMTP delivery, it
773 contains the cipher used for the delivery. The same is true for
776 4. There is now a -Mvc <message-id> option, which outputs a copy of the
777 message to the standard output, in RFC 2822 format. The option can be used
778 only by an admin user.
780 5. There is now a /noupdate option for the ratelimit ACL condition. It
781 computes the rate and checks the limit as normal, but it does not update
782 the saved data. This means that, in relevant ACLs, it is possible to lookup
783 the existence of a specified (or auto-generated) ratelimit key without
784 incrementing the ratelimit counter for that key.
786 In order for this to be useful, another ACL entry must set the rate
787 for the same key somewhere (otherwise it will always be zero).
792 # Read the rate; if it doesn't exist or is below the maximum
794 deny ratelimit = 100 / 5m / strict / noupdate
795 log_message = RATE: $sender_rate / $sender_rate_period \
796 (max $sender_rate_limit)
798 [... some other logic and tests...]
800 warn ratelimit = 100 / 5m / strict / per_cmd
801 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
802 (max $sender_rate_limit)
803 condition = ${if le{$sender_rate}{$sender_rate_limit}}
807 6. The variable $max_received_linelength contains the number of bytes in the
808 longest line that was received as part of the message, not counting the
809 line termination character(s).
811 7. Host lists can now include +ignore_defer and +include_defer, analagous to
812 +ignore_unknown and +include_unknown. These options should be used with
813 care, probably only in non-critical host lists such as whitelists.
815 8. There's a new option called queue_only_load_latch, which defaults true.
816 If set false when queue_only_load is greater than zero, Exim re-evaluates
817 the load for each incoming message in an SMTP session. Otherwise, once one
818 message is queued, the remainder are also.
820 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
821 cases when an SMTP session ends without sending QUIT. However, when Exim
822 itself is is bad trouble, such as being unable to write to its log files,
823 this ACL is not run, because it might try to do things (such as write to
824 log files) that make the situation even worse.
826 Like the QUIT ACL, this new ACL is provided to make it possible to gather
827 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
828 modifier is forbidden in this ACL.
830 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
831 to a string that indicates the reason for the termination of the SMTP
832 connection. The possible values are:
834 acl-drop Another ACL issued a "drop" command
835 bad-commands Too many unknown or non-mail commands
836 command-timeout Timeout while reading SMTP commands
837 connection-lost The SMTP connection has been lost
838 data-timeout Timeout while reading message data
839 local-scan-error The local_scan() function crashed
840 local-scan-timeout The local_scan() function timed out
841 signal-exit SIGTERM or SIGINT
842 synchronization-error SMTP synchronization error
843 tls-failed TLS failed to start
845 In most cases when an SMTP connection is closed without having received
846 QUIT, Exim sends an SMTP response message before actually closing the
847 connection. With the exception of acl-drop, the default message can be
848 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
849 "drop" verb in another ACL, it is the message from the other ACL that is
852 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
853 servers with individual queries. This is done by starting the query with
854 "servers=x:y:z;", where each item in the list may take one of two forms:
856 (1) If it is just a host name, the appropriate global option (mysql_servers
857 or pgsql_servers) is searched for a host of the same name, and the
858 remaining parameters (database, user, password) are taken from there.
860 (2) If it contains any slashes, it is taken as a complete parameter set.
862 The list of servers is used in exactly the same was as the global list.
863 Once a connection to a server has happened and a query has been
864 successfully executed, processing of the lookup ceases.
866 This feature is intended for use in master/slave situations where updates
867 are occurring, and one wants to update a master rather than a slave. If the
868 masters are in the list for reading, you might have:
870 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
872 In an updating lookup, you could then write
874 ${lookup mysql{servers=master; UPDATE ...}
876 If, on the other hand, the master is not to be used for reading lookups:
878 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
880 you can still update the master by
882 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
884 11. The message_body_newlines option (default FALSE, for backwards
885 compatibility) can be used to control whether newlines are present in
886 $message_body and $message_body_end. If it is FALSE, they are replaced by
893 1. There is a new log selector called smtp_no_mail, which is not included in
894 the default setting. When it is set, a line is written to the main log
895 whenever an accepted SMTP connection terminates without having issued a
898 2. When an item in a dnslists list is followed by = and & and a list of IP
899 addresses, the behaviour was not clear when the lookup returned more than
900 one IP address. This has been solved by the addition of == and =& for "all"
901 rather than the default "any" matching.
903 3. Up till now, the only control over which cipher suites GnuTLS uses has been
904 for the cipher algorithms. New options have been added to allow some of the
905 other parameters to be varied.
907 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
908 set, Exim compiles a runtime option called disable_fsync.
910 5. There is a new variable called $smtp_count_at_connection_start.
912 6. There's a new control called no_pipelining.
914 7. There are two new variables called $sending_ip_address and $sending_port.
915 These are set whenever an SMTP connection to another host has been set up.
917 8. The expansion of the helo_data option in the smtp transport now happens
918 after the connection to the server has been made.
920 9. There is a new expansion operator ${rfc2047d: that decodes strings that
921 are encoded as per RFC 2047.
923 10. There is a new log selector called "pid", which causes the current process
924 id to be added to every log line, in square brackets, immediately after the
927 11. Exim has been modified so that it flushes SMTP output before implementing
928 a delay in an ACL. It also flushes the output before performing a callout,
929 as this can take a substantial time. These behaviours can be disabled by
930 obeying control = no_delay_flush or control = no_callout_flush,
931 respectively, at some earlier stage of the connection.
933 12. There are two new expansion conditions that iterate over a list. They are
934 called forany and forall.
936 13. There's a new global option called dsn_from that can be used to vary the
937 contents of From: lines in bounces and other automatically generated
938 messages ("delivery status notifications" - hence the name of the option).
940 14. The smtp transport has a new option called hosts_avoid_pipelining.
942 15. By default, exigrep does case-insensitive matches. There is now a -I option
943 that makes it case-sensitive.
945 16. A number of new features ("addresses", "map", "filter", and "reduce") have
946 been added to string expansions to make it easier to process lists of
947 items, typically addresses.
949 17. There's a new ACL modifier called "continue". It does nothing of itself,
950 and processing of the ACL always continues with the next condition or
951 modifier. It is provided so that the side effects of expanding its argument
954 18. It is now possible to use newline and other control characters (those with
955 values less than 32, plus DEL) as separators in lists.
957 19. The exigrep utility now has a -v option, which inverts the matching
960 20. The host_find_failed option in the manualroute router can now be set to
967 No new features were added to 4.66.
973 No new features were added to 4.65.
979 1. ACL variables can now be given arbitrary names, as long as they start with
980 "acl_c" or "acl_m" (for connection variables and message variables), are at
981 least six characters long, with the sixth character being either a digit or
984 2. There is a new ACL modifier called log_reject_target. It makes it possible
985 to specify which logs are used for messages about ACL rejections.
987 3. There is a new authenticator called "dovecot". This is an interface to the
988 authentication facility of the Dovecot POP/IMAP server, which can support a
989 number of authentication methods.
991 4. The variable $message_headers_raw provides a concatenation of all the
992 messages's headers without any decoding. This is in contrast to
993 $message_headers, which does RFC2047 decoding on the header contents.
995 5. In a DNS black list, if two domain names, comma-separated, are given, the
996 second is used first to do an initial check, making use of any IP value
997 restrictions that are set. If there is a match, the first domain is used,
998 without any IP value restrictions, to get the TXT record.
1000 6. All authenticators now have a server_condition option.
1002 7. There is a new command-line option called -Mset. It is useful only in
1003 conjunction with -be (that is, when testing string expansions). It must be
1004 followed by a message id; Exim loads the given message from its spool
1005 before doing the expansions.
1007 8. Another similar new command-line option is called -bem. It operates like
1008 -be except that it must be followed by the name of a file that contains a
1011 9. When an address is delayed because of a 4xx response to a RCPT command, it
1012 is now the combination of sender and recipient that is delayed in
1013 subsequent queue runs until its retry time is reached.
1015 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1016 shift, have been added to the eval: and eval10: expansion items.
1018 11. The variables $interface_address and $interface_port have been renamed
1019 as $received_ip_address and $received_port, to make it clear that they
1020 relate to message reception rather than delivery. (The old names remain
1021 available for compatibility.)
1023 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1024 to vary the message that is sent when an SMTP command is accepted.
1030 1. There is a new Boolean option called filter_prepend_home for the redirect
1033 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1034 start of receiving a non-SMTP message, before any of the message has been
1037 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1038 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1039 start of the message for an SMTP error code.
1041 4. There is a new parameter for LDAP lookups called "referrals", which takes
1042 one of the settings "follow" (the default) or "nofollow".
1044 5. Version 20070721.2 of exipick now included, offering these new options:
1046 After all other sorting options have bee processed, reverse order
1047 before displaying messages (-R is synonym).
1049 Randomize order of matching messages before displaying.
1051 Instead of displaying the matching messages, display the sum
1053 --sort <variable>[,<variable>...]
1054 Before displaying matching messages, sort the messages according to
1055 each messages value for each variable.
1057 Negate the value for every test (returns inverse output from the
1058 same criteria without --not).
1064 1. The ${readsocket expansion item now supports Internet domain sockets as well
1065 as Unix domain sockets. If the first argument begins "inet:", it must be of
1066 the form "inet:host:port". The port is mandatory; it may be a number or the
1067 name of a TCP port in /etc/services. The host may be a name, or it may be an
1068 IP address. An ip address may optionally be enclosed in square brackets.
1069 This is best for IPv6 addresses. For example:
1071 ${readsocket{inet:[::1]:1234}{<request data>}...
1073 Only a single host name may be given, but if looking it up yield more than
1074 one IP address, they are each tried in turn until a connection is made. Once
1075 a connection has been made, the behaviour is as for ${readsocket with a Unix
1078 2. If a redirect router sets up file or pipe deliveries for more than one
1079 incoming address, and the relevant transport has batch_max set greater than
1080 one, a batch delivery now occurs.
1082 3. The appendfile transport has a new option called maildirfolder_create_regex.
1083 Its value is a regular expression. For a maildir delivery, this is matched
1084 against the maildir directory; if it matches, Exim ensures that a
1085 maildirfolder file is created alongside the new, cur, and tmp directories.
1091 The documentation is up-to-date for the 4.61 release. Major new features since
1092 the 4.60 release are:
1094 . An option called disable_ipv6, to disable the use of IPv6 completely.
1096 . An increase in the number of ACL variables to 20 of each type.
1098 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1099 $2, $3, (though those are still set) because the numeric variables get used
1100 for other things in complicated expansions.
1102 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1104 . It is possible to use setclassresources() on some BSD OS to control the
1105 resources used in pipe deliveries.
1107 . A new ACL modifier called add_header, which can be used with any verb.
1109 . More errors are detectable in retry rules.
1111 There are a number of other additions too.
1117 The documentation is up-to-date for the 4.60 release. Major new features since
1118 the 4.50 release are:
1120 . Support for SQLite.
1122 . Support for IGNOREQUOTA in LMTP.
1124 . Extensions to the "submission mode" features.
1126 . Support for Client SMTP Authorization (CSA).
1128 . Support for ratelimiting hosts and users.
1130 . New expansion items to help with the BATV "prvs" scheme.
1132 . A "match_ip" condition, that matches an IP address against a list.
1134 There are many more minor changes.
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