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. Dual-certificate stacks on servers now support OCSP stapling, under GnuTLS
13 version 3.5.6 or later.
15 2. DANE is now supported under GnuTLS version 3.0.0 or later (adding to the
16 previous OpenSSL implementation, but still Experimental).
18 3. Feature macros for the compiled-in set of malware scanner interfaces.
24 1. PKG_CONFIG_PATH can now be set in Local/Makefile;
25 wildcards will be expanded, values are collapsed.
27 2. The ${readsocket } expansion now takes an option to not shutdown the
28 connection after sending the query string. The default remains to do so.
30 3. An smtp transport option "hosts_noproxy_tls" to control whether multiple
31 deliveries on a single TCP connection can maintain a TLS connection
32 open. By default disabled for all hosts, doing so saves the cost of
33 making new TLS sessions, at the cost of having to proxy the data via
34 another process. Logging is also affected.
36 4. A malware connection type for the FPSCAND protocol.
38 5. An option for recipient verify callouts to hold the connection open for
39 further recipients and for delivery.
41 6. The reproducible build $SOURCE_DATE_EPOCH environment variable is now
44 7. Optionally, an alternate format for spool data-files which matches the
45 wire format - meaning more efficient reception and transmission (at the
46 cost of difficulty with standard Unix tools). Only used for messages
47 received using the ESMTP CHUNKING option, and when a new main-section
48 option "spool_wireformat" (false by default) is set.
50 8. New main configuration option "commandline_checks_require_admin" to
51 restrict who can use various introspection options.
53 9. New option modifier "no_check" for quota and quota_filecount
56 10. Variable $smtp_command_history returning a comma-sep list of recent
59 11. Millisecond timetamps in logs, on log_selector "millisec". Also affects
60 log elements QT, DT and D, and timstamps in debug output.
62 12. TCP Fast Open logging. As a server, logs when the SMTP banner was sent
63 while still in SYN_RECV state; as a client logs when the connection
64 is opened with a TFO cookie.
66 13. DKIM support for multiple signing, by domain and/or key-selector.
67 DKIM support for multiple hashes, and for alternate-identity tags.
68 Builtin macro with default list of signed headers.
69 Better syntax for specifying oversigning.
70 The DKIM ACL can override verification status, and status is visible in
73 14. Exipick understands -C|--config for an alternative Exim
76 15. TCP Fast Open used, with data-on-SYN, for client SMTP via SOCKS5 proxy,
77 for ${readsocket } expansions, and for ClamAV.
79 16. The "-be" expansion test mode now supports macros. Macros are expanded
80 in test lines, and new macros can be defined.
82 17. Support for server-side dual-certificate-stacks (eg. RSA + ECDSA).
88 1. Allow relative config file names for ".include"
90 2. A main-section config option "debug_store" to control the checks on
91 variable locations during store-reset. Normally false but can be enabled
92 when a memory corrution issue is suspected on a production system.
98 1. The new perl_taintmode option allows to run the embedded perl
99 interpreter in taint mode.
101 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
103 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
106 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
107 N can be 224, 256 (default), 384, 512.
108 With GnuTLS 3.5.0 or later, only.
110 5. Facility for named queues: A command-line argument can specify
111 the queue name for a queue operation, and an ACL modifier can set
112 the queue to be used for a message. A $queue_name variable gives
115 6. New expansion operators base32/base32d.
117 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
118 performance increase and network load decrease. Main config option
119 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
122 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
124 9. Expansion operator escape8bit, like escape but not touching newline etc..
126 10. Feature macros, generated from compile options. All start with "_HAVE_"
127 and go on with some roughly recognisable name. Driver macros, for
128 router, transport and authentication drivers; names starting with "_DRIVER_".
129 Option macros, for each configuration-file option; all start with "_OPT_".
130 Use the "-bP macros" command-line option to see what is present.
132 11. Integer values for options can take a "G" multiplier.
134 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
135 returns from the target back to the initiator, rather than spooling the
138 13. New built-in constants available for tls_dhparam and default changed.
140 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
141 out copies of the message spool files for use by 3rd-party scanners.
143 15. A new option on the smtp transport, hosts_try_fastopen. If the system
144 supports it (on Linux it must be enabled in the kernel by the sysadmin)
145 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
146 but it permits a peer that also supports the facility to send its SMTP
147 banner immediately after the SYN,ACK segment rather then waiting for
148 another ACK - so saving up to one roundtrip time. Because it requires
149 previous communication with the peer (we save a cookie from it) this
150 will only become active on frequently-contacted destinations.
152 16. A new syslog_pid option to suppress PID duplication in syslog lines.
158 1. The ACL conditions regex and mime_regex now capture substrings
159 into numeric variables $regex1 to 9, like the "match" expansion condition.
161 2. New $callout_address variable records the address used for a spam=,
162 malware= or verify= callout.
164 3. Transports now take a "max_parallel" option, to limit concurrency.
166 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
167 The latter expands to a 8-element colon-sep set of hex digits including
168 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
169 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
170 The former operator strips leading zeroes and collapses the longest
171 set of 0-groups to a double-colon.
173 5. New "-bP config" support, to dump the effective configuration.
175 6. New $dkim_key_length variable.
177 7. New base64d and base64 expansion items (the existing str2b64 being a
178 synonym of the latter). Add support in base64 for certificates.
180 8. New main configuration option "bounce_return_linesize_limit" to
181 avoid oversize bodies in bounces. The default value matches RFC
184 9. New $initial_cwd expansion variable.
190 1. Support for using the system standard CA bundle.
192 2. New expansion items $config_file, $config_dir, containing the file
193 and directory name of the main configuration file. Also $exim_version.
195 3. New "malware=" support for Avast.
197 4. New "spam=" variant option for Rspamd.
199 5. Assorted options on malware= and spam= scanners.
201 6. A command-line option to write a comment into the logfile.
203 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
204 be configured to make connections via socks5 proxies.
206 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
207 the transmission of UTF-8 envelope addresses.
209 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
210 used encoding of Maildir folder names.
212 10. A logging option for slow DNS lookups.
214 11. New ${env {<variable>}} expansion.
216 12. A non-SMTP authenticator using information from TLS client certificates.
218 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
219 Patch originally by Wolfgang Breyha.
221 14. Main option "dns_trust_aa" for trusting your local nameserver at the
222 same level as DNSSEC.
228 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
229 DANE SMTP draft to assess a secure chain of trust of the certificate
230 used to establish the TLS connection based on a TLSA record in the
231 domain of the sender.
233 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
234 and several new events have been created. The reason is because it has
235 been expanded beyond just firing events during the transport phase. Any
236 existing TPDA transport options will have to be rewritten to use a new
237 $event_name expansion variable in a condition. Refer to the
238 experimental-spec.txt for details and examples.
240 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
241 server certs used for TLS match the result of the MX lookup. It does
242 not use the same mechanism as DANE.
252 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
253 configured to expect an initial header from a proxy that will make the
254 actual external source IP:host be used in exim instead of the IP of the
255 proxy that is connecting to it.
257 2. New verify option header_names_ascii, which will check to make sure
258 there are no non-ASCII characters in header names. Exim itself handles
259 those non-ASCII characters, but downstream apps may not, so Exim can
260 detect and reject if those characters are present.
262 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
263 codepoints with valid ones.
265 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
266 command line and matching a regex against the return data for trigger
267 and a second regex to extract malware_name. The mail spoolfile name can
268 be included in the command line.
270 5. The smtp transport now supports options "tls_verify_hosts" and
271 "tls_try_verify_hosts". If either is set the certificate verification
272 is split from the encryption operation. The default remains that a failed
273 verification cancels the encryption.
275 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
276 lookup can now set a list of servers to use that is different from the
279 7. New command-line option -C for exiqgrep to specify alternate exim.conf
280 file when searching the queue.
282 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
284 9. Support for DNSSEC on outbound connections.
286 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
287 "certextract" to extract fields from them. Hash operators md5 and sha1
288 work over them for generating fingerprints, and a new sha256 operator
291 11. PRDR is now supported dy default.
293 12. OCSP stapling is now supported by default.
295 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
296 Delivery Status Notification messages in MIME format, and negotiate
297 DSN features per RFC 3461.
303 1. New command-line option -bI:sieve will list all supported sieve extensions
304 of this Exim build on standard output, one per line.
305 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
306 query this to establish the correct list to include in the protocol's
307 SIEVE capability line.
309 2. If the -n option is combined with the -bP option, then the name of an
310 emitted option is not output, only the value (if visible to you).
311 For instance, "exim -n -bP pid_file_path" should just emit a pathname
312 followed by a newline, and no other text.
314 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
315 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
316 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
317 acceptable for security. (Option accepted but ignored if using OpenSSL).
318 Defaults to 1024, the old value. May be lowered only to 512, or raised as
319 far as you like. Raising this may hinder TLS interoperability with other
320 sites and is not currently recommended. Lowering this will permit you to
321 establish a TLS session which is not as secure as you might like.
323 Unless you really know what you are doing, leave it alone.
325 4. If not built with DISABLE_DNSSEC, Exim now has the main option
326 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
327 to send the DO flag to your recursive resolver. If you have a recursive
328 resolver, which can set the Authenticated Data (AD) flag in results, Exim
329 can now detect this. Exim does not perform validation itself, instead
330 relying upon a trusted path to the resolver.
332 Current status: work-in-progress; $sender_host_dnssec variable added.
334 5. DSCP support for outbound connections: on a transport using the smtp driver,
335 set "dscp = ef", for instance, to cause the connections to have the relevant
336 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
338 Similarly for inbound connections, there is a new control modifier, dscp,
339 so "warn control = dscp/ef" in the connect ACL, or after authentication.
341 Supported values depend upon system libraries. "exim -bI:dscp" to list the
342 ones Exim knows of. You can also set a raw number 0..0x3F.
344 6. The -G command-line flag is no longer ignored; it is now equivalent to an
345 ACL setting "control = suppress_local_fixups". The -L command-line flag
346 is now accepted and forces use of syslog, with the provided tag as the
347 process name. A few other flags used by Sendmail are now accepted and
350 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
351 ACL modifier; works for single-recipient mails which are received on and
352 deliverable via SMTP. Using the connection made for a recipient verify,
353 if requested before the verify, or a new one made for the purpose while
354 the inbound connection is still active. The bulk of the mail item is copied
355 direct from the inbound socket to the outbound (as well as the spool file).
356 When the source notifies the end of data, the data acceptance by the destination
357 is negotiated before the acceptance is sent to the source. If the destination
358 does not accept the mail item, for example due to content-scanning, the item
359 is not accepted from the source and therefore there is no need to generate
360 a bounce mail. This is of benefit when providing a secondary-MX service.
361 The downside is that delays are under the control of the ultimate destination
364 The Received-by: header on items delivered by cutthrough is generated
365 early in reception rather than at the end; this will affect any timestamp
366 included. The log line showing delivery is recorded before that showing
367 reception; it uses a new ">>" tag instead of "=>".
369 To support the feature, verify-callout connections can now use ESMTP and TLS.
370 The usual smtp transport options are honoured, plus a (new, default everything)
371 hosts_verify_avoid_tls.
373 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
374 for specific access to the information for each connection. The old names
375 are present for now but deprecated.
377 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
379 8. New expansion operators ${listnamed:name} to get the content of a named list
380 and ${listcount:string} to count the items in a list.
382 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
383 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
384 modules. For some situations this is desirable, but we expect admin in
385 those situations to know they want the feature. More commonly, it means
386 that GUI user modules get loaded and are broken by the setuid Exim being
387 unable to access files specified in environment variables and passed
388 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
389 unless this new option is set.
391 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
392 so have also added a build option which can be used to build Exim with GnuTLS
393 but without trying to use any kind of PKCS11 support. Uncomment this in the
396 AVOID_GNUTLS_PKCS11=yes
398 10. The "acl = name" condition on an ACL now supports optional arguments.
399 New expansion item "${acl {name}{arg}...}" and expansion condition
400 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
401 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
402 Variable $acl_narg contains the number of arguments. If the ACL sets
403 a "message =" value this becomes the result of the expansion item,
404 or the value of $value for the expansion condition. If the ACL returns
405 accept the expansion condition is true; if reject, false. A defer
406 return results in a forced fail.
408 11. Routers and transports can now have multiple headers_add and headers_remove
409 option lines. The concatenated list is used.
411 12. New ACL modifier "remove_header" can remove headers before message gets
412 handled by routers/transports.
414 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
415 "aaaa" and "a" lookups is done and the full set of results returned.
417 14. New expansion variable $headers_added with content from ACL add_header
418 modifier (but not yet added to message).
420 15. New 8bitmime status logging option for received messages. Log field "M8S".
422 16. New authenticated_sender logging option, adding to log field "A".
424 17. New expansion variables $router_name and $transport_name. Useful
425 particularly for debug_print as -bt command-line option does not
426 require privilege whereas -d does.
428 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
429 proposed extension to SMTP from Eric Hall.
431 19. The pipe transport has gained the force_command option, to allow
432 decorating commands from user .forward pipe aliases with prefix
433 wrappers, for instance.
435 20. Callout connections can now AUTH; the same controls as normal delivery
438 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
439 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
440 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
441 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
442 dmarc_status. It adds new control flags dmarc_disable_verify and
443 dmarc_enable_forensic. The default for the dmarc_tld_file option is
444 "/etc/exim/opendmarc.tlds" and can be changed via EDITME.
446 22. Add expansion variable $authenticated_fail_id, which is the username
447 provided to the authentication method which failed. It is available
448 for use in subsequent ACL processing (typically quit or notquit ACLs).
450 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
453 24. New ${hexquote:..string..} expansion operator converts non-printable
454 characters in the string to \xNN form.
456 25. Experimental TPDA (Transport Post Delivery Action) function added.
457 Patch provided by Axel Rau.
459 26. Experimental Redis lookup added. Patch provided by Warren Baker.
465 1. New authenticator driver, "gsasl". Server-only (at present).
466 This is a SASL interface, licensed under GPL, which can be found at
467 http://www.gnu.org/software/gsasl/.
468 This system does not provide sources of data for authentication, so
469 careful use needs to be made of the conditions in Exim.
471 2. New authenticator driver, "heimdal_gssapi". Server-only.
472 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
473 is no longer honoured for setuid programs by Heimdal. Use the
474 "server_keytab" option to point to the keytab.
476 3. The "pkg-config" system can now be used when building Exim to reference
477 cflags and library information for lookups and authenticators, rather
478 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
479 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
480 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
482 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
483 find the headers and libraries for PCRE.
485 4. New expansion variable $tls_bits.
487 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
488 be joined together with ASCII NUL characters to construct the key to pass
489 into the DBM library. Can be used with gsasl to access sasldb2 files as
492 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
494 Avoid release 1.0.1a if you can. Note that the default value of
495 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
496 increased susceptibility to attack. This may still have interoperability
497 implications for very old clients (see version 4.31 change 37) but
498 administrators can choose to make the trade-off themselves and restore
499 compatibility at the cost of session security.
501 7. Use of the new expansion variable $tls_sni in the main configuration option
502 tls_certificate will cause Exim to re-expand the option, if the client
503 sends the TLS Server Name Indication extension, to permit choosing a
504 different certificate; tls_privatekey will also be re-expanded. You must
505 still set these options to expand to valid files when $tls_sni is not set.
507 The SMTP Transport has gained the option tls_sni, which will set a hostname
508 for outbound TLS sessions, and set $tls_sni too.
510 A new log_selector, +tls_sni, has been added, to log received SNI values
511 for Exim as a server.
513 8. The existing "accept_8bitmime" option now defaults to true. This means
514 that Exim is deliberately not strictly RFC compliant. We're following
515 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
516 Those who disagree, or know that they are talking to mail servers that,
517 even today, are not 8-bit clean, need to turn off this option.
519 9. Exim can now be started with -bw (with an optional timeout, given as
520 -bw<timespec>). With this, stdin at startup is a socket that is
521 already listening for connections. This has a more modern name of
522 "socket activation", but forcing the activated socket to fd 0. We're
523 interested in adding more support for modern variants.
525 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
526 for numbers indicates multiplication by 1024^3.
528 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
529 gnutls_require_mac & gnutls_require_protocols are no longer supported.
530 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
531 string, documentation for which is at:
532 http://www.gnutls.org/manual/html_node/Priority-Strings.html
534 SNI support has been added to Exim's GnuTLS integration too.
536 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
537 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
539 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
540 is now available. If the contents of the file are valid, then Exim will
541 send that back in response to a TLS status request; this is OCSP Stapling.
542 Exim will not maintain the contents of the file in any way: administrators
543 are responsible for ensuring that it is up-to-date.
545 See "experimental-spec.txt" for more details.
547 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
548 identically to TXT record lookups.
550 14. New expansion variable $tod_epoch_l for higher-precision time.
552 15. New global option tls_dh_max_bits, defaulting to current value of NSS
553 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
554 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
556 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
557 Option can now be a path or an identifier for a standard prime.
558 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
559 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
562 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
563 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
564 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
570 1. New options for the ratelimit ACL condition: /count= and /unique=.
571 The /noupdate option has been replaced by a /readonly option.
573 2. The SMTP transport's protocol option may now be set to "smtps", to
574 use SSL-on-connect outbound.
576 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
577 there is a problem talking to the AV scanner, or the AV scanner running.
579 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
580 and check if the search item is a member of the list. This does not
581 support named lists, but does subject the list part to string expansion.
583 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
584 built, Exim no longer performs string expansion on the second string of
585 the match_* expansion conditions: "match_address", "match_domain",
586 "match_ip" & "match_local_part". Named lists can still be used.
592 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
593 or off in the resolver library.
599 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
600 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
601 libraries. The following global options have been added in support of
602 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
603 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
605 2. The pipe transport now takes a boolean option, "freeze_signal", default
606 false. When true, if the external delivery command exits on a signal then
607 Exim will freeze the message in the queue, instead of generating a bounce.
609 3. Log filenames may now use %M as an escape, instead of %D (still available).
610 The %M pattern expands to yyyymm, providing month-level resolution.
612 4. The $message_linecount variable is now updated for the maildir_tag option,
613 in the same way as $message_size, to reflect the real number of lines,
614 including any header additions or removals from transport.
616 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
617 Exim now selects entries randomly, to better scale in a cluster setup.
623 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
624 the flaw permitted the Exim run-time user to cause root to append to
625 arbitrary files of the attacker's choosing, with the content based
626 on content supplied by the attacker.
628 2. Exim now supports loading some lookup types at run-time, using your
629 platform's dlopen() functionality. This has limited platform support
630 and the intention is not to support every variant, it's limited to
631 dlopen(). This permits the main Exim binary to not be linked against
632 all the libraries needed for all the lookup types.
638 NOTE: this version is not guaranteed backwards-compatible, please read the
639 items below carefully
641 1. A new main configuration option, "openssl_options", is available if Exim
642 is built with SSL support provided by OpenSSL. The option allows
643 administrators to specify OpenSSL options to be used on connections;
644 typically this is to set bug compatibility features which the OpenSSL
645 developers have not enabled by default. There may be security
646 consequences for certain options, so these should not be changed
649 2. A new pipe transport option, "permit_coredumps", may help with problem
650 diagnosis in some scenarios. Note that Exim is typically installed as
651 a setuid binary, which on most OSes will inhibit coredumps by default,
652 so that safety mechanism would have to be overridden for this option to
653 be able to take effect.
655 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
656 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
657 Note that this switches Exim to use a new API ("INSTREAM") and a future
658 release of ClamAV will remove support for the old API ("STREAM").
660 The av_scanner option, when set to "clamd", now takes an optional third
661 part, "local", which causes Exim to pass a filename to ClamAV instead of
662 the file content. This is the same behaviour as when clamd is pointed at
663 a Unix-domain socket. For example:
665 av_scanner = clamd:192.0.2.3 1234:local
667 ClamAV's ExtendedDetectionInfo response format is now handled.
669 4. There is now a -bmalware option, restricted to admin users. This option
670 takes one parameter, a filename, and scans that file with Exim's
671 malware-scanning framework. This is intended purely as a debugging aid
672 to ensure that Exim's scanning is working, not to replace other tools.
673 Note that the ACL framework is not invoked, so if av_scanner references
674 ACL variables without a fallback then this will fail.
676 5. There is a new expansion operator, "reverse_ip", which will reverse IP
677 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
679 ${reverse_ip:192.0.2.4}
681 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
682 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
684 6. There is a new ACL control called "debug", to enable debug logging.
685 This allows selective logging of certain incoming transactions within
686 production environments, with some care. It takes two options, "tag"
687 and "opts"; "tag" is included in the filename of the log and "opts"
688 is used as per the -d<options> command-line option. Examples, which
689 don't all make sense in all contexts:
692 control = debug/tag=.$sender_host_address
693 control = debug/opts=+expand+acl
694 control = debug/tag=.$message_exim_id/opts=+expand
696 7. It has always been implicit in the design and the documentation that
697 "the Exim user" is not root. src/EDITME said that using root was
698 "very strongly discouraged". This is not enough to keep people from
699 shooting themselves in the foot in days when many don't configure Exim
700 themselves but via package build managers. The security consequences of
701 running various bits of network code are severe if there should be bugs in
702 them. As such, the Exim user may no longer be root. If configured
703 statically, Exim will refuse to build. If configured as ref:user then Exim
704 will exit shortly after start-up. If you must shoot yourself in the foot,
705 then henceforth you will have to maintain your own local patches to strip
708 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
709 condition logic to determine truth/failure and will fail to expand many
710 strings, bool_lax{} uses the router condition logic, where most strings
712 Note: bool{00} is false, bool_lax{00} is true.
714 9. Routers now support multiple "condition" tests.
716 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
717 Setting this allows an admin to define which entry in the tcpwrappers
718 config file will be used to control access to the daemon. This option
719 is only available when Exim is built with USE_TCP_WRAPPERS. The
720 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
723 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
724 the Exim run-time user, instead of root.
726 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
727 is forced on. This is mitigated by the new build option
728 TRUSTED_CONFIG_LIST which defines a list of configuration files which
729 are trusted; one per line. If a config file is owned by root and matches
730 a pathname in the list, then it may be invoked by the Exim build-time
731 user without Exim relinquishing root privileges.
733 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
734 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
735 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
736 include the main config. As a transition mechanism, we are temporarily
737 providing a work-around: the new build option WHITELIST_D_MACROS provides
738 a colon-separated list of macro names which may be overridden by the Exim
739 run-time user. The values of these macros are constrained to the regex
740 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
746 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
747 writable, the other to locking of MBX folders (not mbox).
749 2. MySQL stored procedures are now supported.
751 3. The dkim_domain transport option is now a list, not a single string, and
752 messages will be signed for each element in the list (discarding
755 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
756 in the presence of multiple character strings within the RR. Prior to 4.70,
757 only the first string would be returned. The dnsdb lookup now, by default,
758 preserves the pre-4.70 semantics, but also now takes an extended output
759 separator specification. The separator can be followed by a semicolon, to
760 concatenate the individual text strings together with no join character,
761 or by a comma and a second separator character, in which case the text
762 strings within a TXT record are joined on that second character.
763 Administrators are reminded that DNS provides no ordering guarantees
764 between multiple records in an RRset. For example:
766 foo.example. IN TXT "a" "b" "c"
767 foo.example. IN TXT "d" "e" "f"
769 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
770 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
771 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
777 1. Native DKIM support without an external library.
778 (Note that if no action to prevent it is taken, a straight upgrade will
779 result in DKIM verification of all signed incoming emails. See spec
780 for details on conditionally disabling)
782 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
784 3. There is now a bool{} expansion condition which maps certain strings to
785 true/false condition values (most likely of use in conjunction with the
786 and{} expansion operator).
788 4. The $spam_score, $spam_bar and $spam_report variables are now available
791 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
792 options, provided that Exim is invoked by an admin_user.
794 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
795 which increases compatibility with older clients at the cost of decreased
796 security. Don't set this unless you need to support such clients.
798 7. There is a new expansion operator, ${randint:...} which will produce a
799 "random" number less than the supplied integer. This randomness is
800 not guaranteed to be cryptographically strong, but depending upon how
801 Exim was built may be better than the most naive schemes.
803 8. Exim now explicitly ensures that SHA256 is available when linked against
806 9. The transport_filter_timeout option now applies to SMTP transports too.
812 1. Preliminary DKIM support in Experimental.
818 1. The body_linecount and body_zerocount C variables are now exported in the
821 2. When a dnslists lookup succeeds, the key that was looked up is now placed
822 in $dnslist_matched. When the key is an IP address, it is not reversed in
823 this variable (though it is, of course, in the actual lookup). In simple
826 deny dnslists = spamhaus.example
828 the key is also available in another variable (in this case,
829 $sender_host_address). In more complicated cases, however, this is not
830 true. For example, using a data lookup might generate a dnslists lookup
833 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
835 If this condition succeeds, the value in $dnslist_matched might be
836 192.168.6.7 (for example).
838 3. Authenticators now have a client_condition option. When Exim is running as
839 a client, it skips an authenticator whose client_condition expansion yields
840 "0", "no", or "false". This can be used, for example, to skip plain text
841 authenticators when the connection is not encrypted by a setting such as:
843 client_condition = ${if !eq{$tls_cipher}{}}
845 Note that the 4.67 documentation states that $tls_cipher contains the
846 cipher used for incoming messages. In fact, during SMTP delivery, it
847 contains the cipher used for the delivery. The same is true for
850 4. There is now a -Mvc <message-id> option, which outputs a copy of the
851 message to the standard output, in RFC 2822 format. The option can be used
852 only by an admin user.
854 5. There is now a /noupdate option for the ratelimit ACL condition. It
855 computes the rate and checks the limit as normal, but it does not update
856 the saved data. This means that, in relevant ACLs, it is possible to lookup
857 the existence of a specified (or auto-generated) ratelimit key without
858 incrementing the ratelimit counter for that key.
860 In order for this to be useful, another ACL entry must set the rate
861 for the same key somewhere (otherwise it will always be zero).
866 # Read the rate; if it doesn't exist or is below the maximum
868 deny ratelimit = 100 / 5m / strict / noupdate
869 log_message = RATE: $sender_rate / $sender_rate_period \
870 (max $sender_rate_limit)
872 [... some other logic and tests...]
874 warn ratelimit = 100 / 5m / strict / per_cmd
875 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
876 (max $sender_rate_limit)
877 condition = ${if le{$sender_rate}{$sender_rate_limit}}
881 6. The variable $max_received_linelength contains the number of bytes in the
882 longest line that was received as part of the message, not counting the
883 line termination character(s).
885 7. Host lists can now include +ignore_defer and +include_defer, analagous to
886 +ignore_unknown and +include_unknown. These options should be used with
887 care, probably only in non-critical host lists such as whitelists.
889 8. There's a new option called queue_only_load_latch, which defaults true.
890 If set false when queue_only_load is greater than zero, Exim re-evaluates
891 the load for each incoming message in an SMTP session. Otherwise, once one
892 message is queued, the remainder are also.
894 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
895 cases when an SMTP session ends without sending QUIT. However, when Exim
896 itself is is bad trouble, such as being unable to write to its log files,
897 this ACL is not run, because it might try to do things (such as write to
898 log files) that make the situation even worse.
900 Like the QUIT ACL, this new ACL is provided to make it possible to gather
901 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
902 modifier is forbidden in this ACL.
904 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
905 to a string that indicates the reason for the termination of the SMTP
906 connection. The possible values are:
908 acl-drop Another ACL issued a "drop" command
909 bad-commands Too many unknown or non-mail commands
910 command-timeout Timeout while reading SMTP commands
911 connection-lost The SMTP connection has been lost
912 data-timeout Timeout while reading message data
913 local-scan-error The local_scan() function crashed
914 local-scan-timeout The local_scan() function timed out
915 signal-exit SIGTERM or SIGINT
916 synchronization-error SMTP synchronization error
917 tls-failed TLS failed to start
919 In most cases when an SMTP connection is closed without having received
920 QUIT, Exim sends an SMTP response message before actually closing the
921 connection. With the exception of acl-drop, the default message can be
922 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
923 "drop" verb in another ACL, it is the message from the other ACL that is
926 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
927 servers with individual queries. This is done by starting the query with
928 "servers=x:y:z;", where each item in the list may take one of two forms:
930 (1) If it is just a host name, the appropriate global option (mysql_servers
931 or pgsql_servers) is searched for a host of the same name, and the
932 remaining parameters (database, user, password) are taken from there.
934 (2) If it contains any slashes, it is taken as a complete parameter set.
936 The list of servers is used in exactly the same was as the global list.
937 Once a connection to a server has happened and a query has been
938 successfully executed, processing of the lookup ceases.
940 This feature is intended for use in master/slave situations where updates
941 are occurring, and one wants to update a master rather than a slave. If the
942 masters are in the list for reading, you might have:
944 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
946 In an updating lookup, you could then write
948 ${lookup mysql{servers=master; UPDATE ...}
950 If, on the other hand, the master is not to be used for reading lookups:
952 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
954 you can still update the master by
956 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
958 11. The message_body_newlines option (default FALSE, for backwards
959 compatibility) can be used to control whether newlines are present in
960 $message_body and $message_body_end. If it is FALSE, they are replaced by
967 1. There is a new log selector called smtp_no_mail, which is not included in
968 the default setting. When it is set, a line is written to the main log
969 whenever an accepted SMTP connection terminates without having issued a
972 2. When an item in a dnslists list is followed by = and & and a list of IP
973 addresses, the behaviour was not clear when the lookup returned more than
974 one IP address. This has been solved by the addition of == and =& for "all"
975 rather than the default "any" matching.
977 3. Up till now, the only control over which cipher suites GnuTLS uses has been
978 for the cipher algorithms. New options have been added to allow some of the
979 other parameters to be varied.
981 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
982 set, Exim compiles a runtime option called disable_fsync.
984 5. There is a new variable called $smtp_count_at_connection_start.
986 6. There's a new control called no_pipelining.
988 7. There are two new variables called $sending_ip_address and $sending_port.
989 These are set whenever an SMTP connection to another host has been set up.
991 8. The expansion of the helo_data option in the smtp transport now happens
992 after the connection to the server has been made.
994 9. There is a new expansion operator ${rfc2047d: that decodes strings that
995 are encoded as per RFC 2047.
997 10. There is a new log selector called "pid", which causes the current process
998 id to be added to every log line, in square brackets, immediately after the
1001 11. Exim has been modified so that it flushes SMTP output before implementing
1002 a delay in an ACL. It also flushes the output before performing a callout,
1003 as this can take a substantial time. These behaviours can be disabled by
1004 obeying control = no_delay_flush or control = no_callout_flush,
1005 respectively, at some earlier stage of the connection.
1007 12. There are two new expansion conditions that iterate over a list. They are
1008 called forany and forall.
1010 13. There's a new global option called dsn_from that can be used to vary the
1011 contents of From: lines in bounces and other automatically generated
1012 messages ("delivery status notifications" - hence the name of the option).
1014 14. The smtp transport has a new option called hosts_avoid_pipelining.
1016 15. By default, exigrep does case-insensitive matches. There is now a -I option
1017 that makes it case-sensitive.
1019 16. A number of new features ("addresses", "map", "filter", and "reduce") have
1020 been added to string expansions to make it easier to process lists of
1021 items, typically addresses.
1023 17. There's a new ACL modifier called "continue". It does nothing of itself,
1024 and processing of the ACL always continues with the next condition or
1025 modifier. It is provided so that the side effects of expanding its argument
1028 18. It is now possible to use newline and other control characters (those with
1029 values less than 32, plus DEL) as separators in lists.
1031 19. The exigrep utility now has a -v option, which inverts the matching
1034 20. The host_find_failed option in the manualroute router can now be set to
1041 No new features were added to 4.66.
1047 No new features were added to 4.65.
1053 1. ACL variables can now be given arbitrary names, as long as they start with
1054 "acl_c" or "acl_m" (for connection variables and message variables), are at
1055 least six characters long, with the sixth character being either a digit or
1058 2. There is a new ACL modifier called log_reject_target. It makes it possible
1059 to specify which logs are used for messages about ACL rejections.
1061 3. There is a new authenticator called "dovecot". This is an interface to the
1062 authentication facility of the Dovecot POP/IMAP server, which can support a
1063 number of authentication methods.
1065 4. The variable $message_headers_raw provides a concatenation of all the
1066 messages's headers without any decoding. This is in contrast to
1067 $message_headers, which does RFC2047 decoding on the header contents.
1069 5. In a DNS black list, if two domain names, comma-separated, are given, the
1070 second is used first to do an initial check, making use of any IP value
1071 restrictions that are set. If there is a match, the first domain is used,
1072 without any IP value restrictions, to get the TXT record.
1074 6. All authenticators now have a server_condition option.
1076 7. There is a new command-line option called -Mset. It is useful only in
1077 conjunction with -be (that is, when testing string expansions). It must be
1078 followed by a message id; Exim loads the given message from its spool
1079 before doing the expansions.
1081 8. Another similar new command-line option is called -bem. It operates like
1082 -be except that it must be followed by the name of a file that contains a
1085 9. When an address is delayed because of a 4xx response to a RCPT command, it
1086 is now the combination of sender and recipient that is delayed in
1087 subsequent queue runs until its retry time is reached.
1089 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1090 shift, have been added to the eval: and eval10: expansion items.
1092 11. The variables $interface_address and $interface_port have been renamed
1093 as $received_ip_address and $received_port, to make it clear that they
1094 relate to message reception rather than delivery. (The old names remain
1095 available for compatibility.)
1097 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1098 to vary the message that is sent when an SMTP command is accepted.
1104 1. There is a new Boolean option called filter_prepend_home for the redirect
1107 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1108 start of receiving a non-SMTP message, before any of the message has been
1111 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1112 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1113 start of the message for an SMTP error code.
1115 4. There is a new parameter for LDAP lookups called "referrals", which takes
1116 one of the settings "follow" (the default) or "nofollow".
1118 5. Version 20070721.2 of exipick now included, offering these new options:
1120 After all other sorting options have bee processed, reverse order
1121 before displaying messages (-R is synonym).
1123 Randomize order of matching messages before displaying.
1125 Instead of displaying the matching messages, display the sum
1127 --sort <variable>[,<variable>...]
1128 Before displaying matching messages, sort the messages according to
1129 each messages value for each variable.
1131 Negate the value for every test (returns inverse output from the
1132 same criteria without --not).
1138 1. The ${readsocket expansion item now supports Internet domain sockets as well
1139 as Unix domain sockets. If the first argument begins "inet:", it must be of
1140 the form "inet:host:port". The port is mandatory; it may be a number or the
1141 name of a TCP port in /etc/services. The host may be a name, or it may be an
1142 IP address. An ip address may optionally be enclosed in square brackets.
1143 This is best for IPv6 addresses. For example:
1145 ${readsocket{inet:[::1]:1234}{<request data>}...
1147 Only a single host name may be given, but if looking it up yield more than
1148 one IP address, they are each tried in turn until a connection is made. Once
1149 a connection has been made, the behaviour is as for ${readsocket with a Unix
1152 2. If a redirect router sets up file or pipe deliveries for more than one
1153 incoming address, and the relevant transport has batch_max set greater than
1154 one, a batch delivery now occurs.
1156 3. The appendfile transport has a new option called maildirfolder_create_regex.
1157 Its value is a regular expression. For a maildir delivery, this is matched
1158 against the maildir directory; if it matches, Exim ensures that a
1159 maildirfolder file is created alongside the new, cur, and tmp directories.
1165 The documentation is up-to-date for the 4.61 release. Major new features since
1166 the 4.60 release are:
1168 . An option called disable_ipv6, to disable the use of IPv6 completely.
1170 . An increase in the number of ACL variables to 20 of each type.
1172 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1173 $2, $3, (though those are still set) because the numeric variables get used
1174 for other things in complicated expansions.
1176 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1178 . It is possible to use setclassresources() on some BSD OS to control the
1179 resources used in pipe deliveries.
1181 . A new ACL modifier called add_header, which can be used with any verb.
1183 . More errors are detectable in retry rules.
1185 There are a number of other additions too.
1191 The documentation is up-to-date for the 4.60 release. Major new features since
1192 the 4.50 release are:
1194 . Support for SQLite.
1196 . Support for IGNOREQUOTA in LMTP.
1198 . Extensions to the "submission mode" features.
1200 . Support for Client SMTP Authorization (CSA).
1202 . Support for ratelimiting hosts and users.
1204 . New expansion items to help with the BATV "prvs" scheme.
1206 . A "match_ip" condition, that matches an IP address against a list.
1208 There are many more minor changes.
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