4 This file contains descriptions of new features that have been added to Exim.
5 Before a formal release, there may be quite a lot of detail so that people can
6 test from the snapshots or the CVS before the documentation is updated. Once
7 the documentation is updated, this file is reduced to a short list.
12 1. The new perl_taintmode option allows to run the embedded perl
13 interpreter in taint mode.
15 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
17 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
20 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
21 N can be 224, 256 (default), 384, 512.
22 With GnuTLS 3.5.0 or later, only.
28 1. The ACL conditions regex and mime_regex now capture substrings
29 into numeric variables $regex1 to 9, like the "match" expansion condition.
31 2. New $callout_address variable records the address used for a spam=,
32 malware= or verify= callout.
34 3. Transports now take a "max_parallel" option, to limit concurrency.
36 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
37 The latter expands to a 8-element colon-sep set of hex digits including
38 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
39 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
40 The former operator strips leading zeroes and collapses the longest
41 set of 0-groups to a double-colon.
43 5. New "-bP config" support, to dump the effective configuration.
45 6. New $dkim_key_length variable.
47 7. New base64d and base64 expansion items (the existing str2b64 being a
48 synonym of the latter). Add support in base64 for certificates.
50 8. New main configuration option "bounce_return_linesize_limit" to
51 avoid oversize bodies in bounces. The dafault value matches RFC
54 9. New $initial_cwd expansion variable.
60 1. Support for using the system standard CA bundle.
62 2. New expansion items $config_file, $config_dir, containing the file
63 and directory name of the main configuration file. Also $exim_version.
65 3. New "malware=" support for Avast.
67 4. New "spam=" variant option for Rspamd.
69 5. Assorted options on malware= and spam= scanners.
71 6. A commandline option to write a comment into the logfile.
73 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
74 be configured to make connections via socks5 proxies.
76 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
77 the transmission of UTF-8 envelope addresses.
79 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
80 used encoding of Maildir folder names.
82 10. A logging option for slow DNS lookups.
84 11. New ${env {<variable>}} expansion.
86 12. A non-SMTP authenticator using information from TLS client certificates.
88 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
89 Patch originally by Wolfgang Breyha.
91 14. Main option "dns_trust_aa" for trusting your local nameserver at the
98 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
99 DANE smtp draft to assess a secure chain of trust of the certificate
100 used to establish the TLS connection based on a TLSA record in the
101 domain of the sender.
103 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
104 and several new events have been created. The reason is because it has
105 been expanded beyond just firing events during the transport phase. Any
106 existing TPDA transport options will have to be rewritten to use a new
107 $event_name expansion variable in a condition. Refer to the
108 experimental-spec.txt for details and examples.
110 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
111 server certs used for TLS match the result of the MX lookup. It does
112 not use the same mechanism as DANE.
122 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
123 configured to expect an initial header from a proxy that will make the
124 actual external source IP:host be used in exim instead of the IP of the
125 proxy that is connecting to it.
127 2. New verify option header_names_ascii, which will check to make sure
128 there are no non-ASCII characters in header names. Exim itself handles
129 those non-ASCII characters, but downstream apps may not, so Exim can
130 detect and reject if those characters are present.
132 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
133 codepoints with valid ones.
135 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
136 command line and matching a regex against the return data for trigger
137 and a second regex to extract malware_name. The mail spoolfile name can
138 be included in the command line.
140 5. The smtp transport now supports options "tls_verify_hosts" and
141 "tls_try_verify_hosts". If either is set the certificate verification
142 is split from the encryption operation. The default remains that a failed
143 verification cancels the encryption.
145 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
146 lookup can now set a list of servers to use that is different from the
149 7. New command-line option -C for exiqgrep to specify alternate exim.conf
150 file when searching the queue.
152 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
154 9. Support for DNSSEC on outbound connections.
156 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
157 "certextract" to extract fields from them. Hash operators md5 and sha1
158 work over them for generating fingerprints, and a new sha256 operator
161 11. PRDR is now supported dy default.
163 12. OCSP stapling is now supported by default.
165 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
166 Delivery Status Notification messages in MIME format, and negociate
167 DSN features per RFC 3461.
173 1. New command-line option -bI:sieve will list all supported sieve extensions
174 of this Exim build on standard output, one per line.
175 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
176 query this to establish the correct list to include in the protocol's
177 SIEVE capability line.
179 2. If the -n option is combined with the -bP option, then the name of an
180 emitted option is not output, only the value (if visible to you).
181 For instance, "exim -n -bP pid_file_path" should just emit a pathname
182 followed by a newline, and no other text.
184 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
185 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
186 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
187 acceptable for security. (Option accepted but ignored if using OpenSSL).
188 Defaults to 1024, the old value. May be lowered only to 512, or raised as
189 far as you like. Raising this may hinder TLS interoperability with other
190 sites and is not currently recommended. Lowering this will permit you to
191 establish a TLS session which is not as secure as you might like.
193 Unless you really know what you are doing, leave it alone.
195 4. If not built with DISABLE_DNSSEC, Exim now has the main option
196 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
197 to send the DO flag to your recursive resolver. If you have a recursive
198 resolver, which can set the Authenticated Data (AD) flag in results, Exim
199 can now detect this. Exim does not perform validation itself, instead
200 relying upon a trusted path to the resolver.
202 Current status: work-in-progress; $sender_host_dnssec variable added.
204 5. DSCP support for outbound connections: on a transport using the smtp driver,
205 set "dscp = ef", for instance, to cause the connections to have the relevant
206 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
208 Similarly for inbound connections, there is a new control modifier, dscp,
209 so "warn control = dscp/ef" in the connect ACL, or after authentication.
211 Supported values depend upon system libraries. "exim -bI:dscp" to list the
212 ones Exim knows of. You can also set a raw number 0..0x3F.
214 6. The -G command-line flag is no longer ignored; it is now equivalent to an
215 ACL setting "control = suppress_local_fixups". The -L command-line flag
216 is now accepted and forces use of syslog, with the provided tag as the
217 process name. A few other flags used by Sendmail are now accepted and
220 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
221 ACL modifier; works for single-recipient mails which are recieved on and
222 deliverable via SMTP. Using the connection made for a recipient verify,
223 if requested before the verify, or a new one made for the purpose while
224 the inbound connection is still active. The bulk of the mail item is copied
225 direct from the inbound socket to the outbound (as well as the spool file).
226 When the source notifies the end of data, the data acceptance by the destination
227 is negociated before the acceptance is sent to the source. If the destination
228 does not accept the mail item, for example due to content-scanning, the item
229 is not accepted from the source and therefore there is no need to generate
230 a bounce mail. This is of benefit when providing a secondary-MX service.
231 The downside is that delays are under the control of the ultimate destination
234 The Recieved-by: header on items delivered by cutthrough is generated
235 early in reception rather than at the end; this will affect any timestamp
236 included. The log line showing delivery is recorded before that showing
237 reception; it uses a new ">>" tag instead of "=>".
239 To support the feature, verify-callout connections can now use ESMTP and TLS.
240 The usual smtp transport options are honoured, plus a (new, default everything)
241 hosts_verify_avoid_tls.
243 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
244 for specific access to the information for each connection. The old names
245 are present for now but deprecated.
247 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
249 8. New expansion operators ${listnamed:name} to get the content of a named list
250 and ${listcount:string} to count the items in a list.
252 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
253 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
254 modules. For some situations this is desirable, but we expect admin in
255 those situations to know they want the feature. More commonly, it means
256 that GUI user modules get loaded and are broken by the setuid Exim being
257 unable to access files specified in environment variables and passed
258 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
259 unless this new option is set.
261 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
262 so have also added a build option which can be used to build Exim with GnuTLS
263 but without trying to use any kind of PKCS11 support. Uncomment this in the
266 AVOID_GNUTLS_PKCS11=yes
268 10. The "acl = name" condition on an ACL now supports optional arguments.
269 New expansion item "${acl {name}{arg}...}" and expansion condition
270 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
271 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
272 Variable $acl_narg contains the number of arguments. If the ACL sets
273 a "message =" value this becomes the result of the expansion item,
274 or the value of $value for the expansion condition. If the ACL returns
275 accept the expansion condition is true; if reject, false. A defer
276 return results in a forced fail.
278 11. Routers and transports can now have multiple headers_add and headers_remove
279 option lines. The concatenated list is used.
281 12. New ACL modifier "remove_header" can remove headers before message gets
282 handled by routers/transports.
284 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
285 "aaaa" and "a" lookups is done and the full set of results returned.
287 14. New expansion variable $headers_added with content from ACL add_header
288 modifier (but not yet added to message).
290 15. New 8bitmime status logging option for received messages. Log field "M8S".
292 16. New authenticated_sender logging option, adding to log field "A".
294 17. New expansion variables $router_name and $transport_name. Useful
295 particularly for debug_print as -bt commandline option does not
296 require privilege whereas -d does.
298 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
299 proposed extension to SMTP from Eric Hall.
301 19. The pipe transport has gained the force_command option, to allow
302 decorating commands from user .forward pipe aliases with prefix
303 wrappers, for instance.
305 20. Callout connections can now AUTH; the same controls as normal delivery
308 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
309 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
310 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
311 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
312 dmarc_status. It adds new control flags dmarc_disable_verify and
313 dmarc_enable_forensic.
315 22. Add expansion variable $authenticated_fail_id, which is the username
316 provided to the authentication method which failed. It is available
317 for use in subsequent ACL processing (typically quit or notquit ACLs).
319 23. New ACL modifer "udpsend" can construct a UDP packet to send to a given
322 24. New ${hexquote:..string..} expansion operator converts non-printable
323 characters in the string to \xNN form.
325 25. Experimental TPDA (Transport Post Delivery Action) function added.
326 Patch provided by Axel Rau.
328 26. Experimental Redis lookup added. Patch provided by Warren Baker.
334 1. New authenticator driver, "gsasl". Server-only (at present).
335 This is a SASL interface, licensed under GPL, which can be found at
336 http://www.gnu.org/software/gsasl/.
337 This system does not provide sources of data for authentication, so
338 careful use needs to be made of the conditions in Exim.
340 2. New authenticator driver, "heimdal_gssapi". Server-only.
341 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
342 is no longer honoured for setuid programs by Heimdal. Use the
343 "server_keytab" option to point to the keytab.
345 3. The "pkg-config" system can now be used when building Exim to reference
346 cflags and library information for lookups and authenticators, rather
347 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
348 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
349 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
351 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
352 find the headers and libraries for PCRE.
354 4. New expansion variable $tls_bits.
356 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
357 be joined together with ASCII NUL characters to construct the key to pass
358 into the DBM library. Can be used with gsasl to access sasldb2 files as
361 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
363 Avoid release 1.0.1a if you can. Note that the default value of
364 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
365 increased susceptibility to attack. This may still have interoperability
366 implications for very old clients (see version 4.31 change 37) but
367 administrators can choose to make the trade-off themselves and restore
368 compatibility at the cost of session security.
370 7. Use of the new expansion variable $tls_sni in the main configuration option
371 tls_certificate will cause Exim to re-expand the option, if the client
372 sends the TLS Server Name Indication extension, to permit choosing a
373 different certificate; tls_privatekey will also be re-expanded. You must
374 still set these options to expand to valid files when $tls_sni is not set.
376 The SMTP Transport has gained the option tls_sni, which will set a hostname
377 for outbound TLS sessions, and set $tls_sni too.
379 A new log_selector, +tls_sni, has been added, to log received SNI values
380 for Exim as a server.
382 8. The existing "accept_8bitmime" option now defaults to true. This means
383 that Exim is deliberately not strictly RFC compliant. We're following
384 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
385 Those who disagree, or know that they are talking to mail servers that,
386 even today, are not 8-bit clean, need to turn off this option.
388 9. Exim can now be started with -bw (with an optional timeout, given as
389 -bw<timespec>). With this, stdin at startup is a socket that is
390 already listening for connections. This has a more modern name of
391 "socket activation", but forcing the activated socket to fd 0. We're
392 interested in adding more support for modern variants.
394 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
395 for numbers indicates multiplication by 1024^3.
397 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
398 gnutls_require_mac & gnutls_require_protocols are no longer supported.
399 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
400 string, documentation for which is at:
401 http://www.gnutls.org/manual/html_node/Priority-Strings.html
403 SNI support has been added to Exim's GnuTLS integration too.
405 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
406 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
408 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
409 is now available. If the contents of the file are valid, then Exim will
410 send that back in response to a TLS status request; this is OCSP Stapling.
411 Exim will not maintain the contents of the file in any way: administrators
412 are responsible for ensuring that it is up-to-date.
414 See "experimental-spec.txt" for more details.
416 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
417 identically to TXT record lookups.
419 14. New expansion variable $tod_epoch_l for higher-precision time.
421 15. New global option tls_dh_max_bits, defaulting to current value of NSS
422 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
423 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
425 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
426 Option can now be a path or an identifier for a standard prime.
427 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
428 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
431 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
432 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
433 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
439 1. New options for the ratelimit ACL condition: /count= and /unique=.
440 The /noupdate option has been replaced by a /readonly option.
442 2. The SMTP transport's protocol option may now be set to "smtps", to
443 use SSL-on-connect outbound.
445 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
446 there is a problem talking to the AV scanner, or the AV scanner running.
448 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
449 and check if the search item is a member of the list. This does not
450 support named lists, but does subject the list part to string expansion.
452 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
453 built, Exim no longer performs string expansion on the second string of
454 the match_* expansion conditions: "match_address", "match_domain",
455 "match_ip" & "match_local_part". Named lists can still be used.
461 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
462 or off in the resolver library.
468 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
469 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
470 libraries. The following global options have been added in support of
471 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
472 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
474 2. The pipe transport now takes a boolean option, "freeze_signal", default
475 false. When true, if the external delivery command exits on a signal then
476 Exim will freeze the message in the queue, instead of generating a bounce.
478 3. Log filenames may now use %M as an escape, instead of %D (still available).
479 The %M pattern expands to yyyymm, providing month-level resolution.
481 4. The $message_linecount variable is now updated for the maildir_tag option,
482 in the same way as $message_size, to reflect the real number of lines,
483 including any header additions or removals from transport.
485 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
486 Exim now selects entries randomly, to better scale in a cluster setup.
492 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
493 the flaw permitted the Exim run-time user to cause root to append to
494 arbitrary files of the attacker's choosing, with the content based
495 on content supplied by the attacker.
497 2. Exim now supports loading some lookup types at run-time, using your
498 platform's dlopen() functionality. This has limited platform support
499 and the intention is not to support every variant, it's limited to
500 dlopen(). This permits the main Exim binary to not be linked against
501 all the libraries needed for all the lookup types.
507 NOTE: this version is not guaranteed backwards-compatible, please read the
508 items below carefully
510 1. A new main configuration option, "openssl_options", is available if Exim
511 is built with SSL support provided by OpenSSL. The option allows
512 administrators to specify OpenSSL options to be used on connections;
513 typically this is to set bug compatibility features which the OpenSSL
514 developers have not enabled by default. There may be security
515 consequences for certain options, so these should not be changed
518 2. A new pipe transport option, "permit_coredumps", may help with problem
519 diagnosis in some scenarios. Note that Exim is typically installed as
520 a setuid binary, which on most OSes will inhibit coredumps by default,
521 so that safety mechanism would have to be overridden for this option to
522 be able to take effect.
524 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
525 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
526 Note that this switches Exim to use a new API ("INSTREAM") and a future
527 release of ClamAV will remove support for the old API ("STREAM").
529 The av_scanner option, when set to "clamd", now takes an optional third
530 part, "local", which causes Exim to pass a filename to ClamAV instead of
531 the file content. This is the same behaviour as when clamd is pointed at
532 a Unix-domain socket. For example:
534 av_scanner = clamd:192.0.2.3 1234:local
536 ClamAV's ExtendedDetectionInfo response format is now handled.
538 4. There is now a -bmalware option, restricted to admin users. This option
539 takes one parameter, a filename, and scans that file with Exim's
540 malware-scanning framework. This is intended purely as a debugging aid
541 to ensure that Exim's scanning is working, not to replace other tools.
542 Note that the ACL framework is not invoked, so if av_scanner references
543 ACL variables without a fallback then this will fail.
545 5. There is a new expansion operator, "reverse_ip", which will reverse IP
546 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
548 ${reverse_ip:192.0.2.4}
550 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
551 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
553 6. There is a new ACL control called "debug", to enable debug logging.
554 This allows selective logging of certain incoming transactions within
555 production environments, with some care. It takes two options, "tag"
556 and "opts"; "tag" is included in the filename of the log and "opts"
557 is used as per the -d<options> command-line option. Examples, which
558 don't all make sense in all contexts:
561 control = debug/tag=.$sender_host_address
562 control = debug/opts=+expand+acl
563 control = debug/tag=.$message_exim_id/opts=+expand
565 7. It has always been implicit in the design and the documentation that
566 "the Exim user" is not root. src/EDITME said that using root was
567 "very strongly discouraged". This is not enough to keep people from
568 shooting themselves in the foot in days when many don't configure Exim
569 themselves but via package build managers. The security consequences of
570 running various bits of network code are severe if there should be bugs in
571 them. As such, the Exim user may no longer be root. If configured
572 statically, Exim will refuse to build. If configured as ref:user then Exim
573 will exit shortly after start-up. If you must shoot yourself in the foot,
574 then henceforth you will have to maintain your own local patches to strip
577 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
578 condition logic to determine truth/failure and will fail to expand many
579 strings, bool_lax{} uses the router condition logic, where most strings
581 Note: bool{00} is false, bool_lax{00} is true.
583 9. Routers now support multiple "condition" tests.
585 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
586 Setting this allows an admin to define which entry in the tcpwrappers
587 config file will be used to control access to the daemon. This option
588 is only available when Exim is built with USE_TCP_WRAPPERS. The
589 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
592 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
593 the Exim run-time user, instead of root.
595 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
596 is forced on. This is mitigated by the new build option
597 TRUSTED_CONFIG_LIST which defines a list of configuration files which
598 are trusted; one per line. If a config file is owned by root and matches
599 a pathname in the list, then it may be invoked by the Exim build-time
600 user without Exim relinquishing root privileges.
602 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
603 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
604 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
605 include the main config. As a transition mechanism, we are temporarily
606 providing a work-around: the new build option WHITELIST_D_MACROS provides
607 a colon-separated list of macro names which may be overridden by the Exim
608 run-time user. The values of these macros are constrained to the regex
609 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
615 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
616 writable, the other to locking of MBX folders (not mbox).
618 2. MySQL stored procedures are now supported.
620 3. The dkim_domain transport option is now a list, not a single string, and
621 messages will be signed for each element in the list (discarding
624 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
625 in the presence of multiple character strings within the RR. Prior to 4.70,
626 only the first string would be returned. The dnsdb lookup now, by default,
627 preserves the pre-4.70 semantics, but also now takes an extended output
628 separator specification. The separator can be followed by a semicolon, to
629 concatenate the individual text strings together with no join character,
630 or by a comma and a second separator character, in which case the text
631 strings within a TXT record are joined on that second character.
632 Administrators are reminded that DNS provides no ordering guarantees
633 between multiple records in an RRset. For example:
635 foo.example. IN TXT "a" "b" "c"
636 foo.example. IN TXT "d" "e" "f"
638 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
639 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
640 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
646 1. Native DKIM support without an external library.
647 (Note that if no action to prevent it is taken, a straight upgrade will
648 result in DKIM verification of all signed incoming emails. See spec
649 for details on conditionally disabling)
651 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
653 3. There is now a bool{} expansion condition which maps certain strings to
654 true/false condition values (most likely of use in conjunction with the
655 and{} expansion operator).
657 4. The $spam_score, $spam_bar and $spam_report variables are now available
660 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
661 options, provided that Exim is invoked by an admin_user.
663 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
664 which increases compatibility with older clients at the cost of decreased
665 security. Don't set this unless you need to support such clients.
667 7. There is a new expansion operator, ${randint:...} which will produce a
668 "random" number less than the supplied integer. This randomness is
669 not guaranteed to be cryptographically strong, but depending upon how
670 Exim was built may be better than the most naive schemes.
672 8. Exim now explicitly ensures that SHA256 is available when linked against
675 9. The transport_filter_timeout option now applies to SMTP transports too.
681 1. Preliminary DKIM support in Experimental.
687 1. The body_linecount and body_zerocount C variables are now exported in the
690 2. When a dnslists lookup succeeds, the key that was looked up is now placed
691 in $dnslist_matched. When the key is an IP address, it is not reversed in
692 this variable (though it is, of course, in the actual lookup). In simple
695 deny dnslists = spamhaus.example
697 the key is also available in another variable (in this case,
698 $sender_host_address). In more complicated cases, however, this is not
699 true. For example, using a data lookup might generate a dnslists lookup
702 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
704 If this condition succeeds, the value in $dnslist_matched might be
705 192.168.6.7 (for example).
707 3. Authenticators now have a client_condition option. When Exim is running as
708 a client, it skips an authenticator whose client_condition expansion yields
709 "0", "no", or "false". This can be used, for example, to skip plain text
710 authenticators when the connection is not encrypted by a setting such as:
712 client_condition = ${if !eq{$tls_cipher}{}}
714 Note that the 4.67 documentation states that $tls_cipher contains the
715 cipher used for incoming messages. In fact, during SMTP delivery, it
716 contains the cipher used for the delivery. The same is true for
719 4. There is now a -Mvc <message-id> option, which outputs a copy of the
720 message to the standard output, in RFC 2822 format. The option can be used
721 only by an admin user.
723 5. There is now a /noupdate option for the ratelimit ACL condition. It
724 computes the rate and checks the limit as normal, but it does not update
725 the saved data. This means that, in relevant ACLs, it is possible to lookup
726 the existence of a specified (or auto-generated) ratelimit key without
727 incrementing the ratelimit counter for that key.
729 In order for this to be useful, another ACL entry must set the rate
730 for the same key somewhere (otherwise it will always be zero).
735 # Read the rate; if it doesn't exist or is below the maximum
737 deny ratelimit = 100 / 5m / strict / noupdate
738 log_message = RATE: $sender_rate / $sender_rate_period \
739 (max $sender_rate_limit)
741 [... some other logic and tests...]
743 warn ratelimit = 100 / 5m / strict / per_cmd
744 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
745 (max $sender_rate_limit)
746 condition = ${if le{$sender_rate}{$sender_rate_limit}}
750 6. The variable $max_received_linelength contains the number of bytes in the
751 longest line that was received as part of the message, not counting the
752 line termination character(s).
754 7. Host lists can now include +ignore_defer and +include_defer, analagous to
755 +ignore_unknown and +include_unknown. These options should be used with
756 care, probably only in non-critical host lists such as whitelists.
758 8. There's a new option called queue_only_load_latch, which defaults true.
759 If set false when queue_only_load is greater than zero, Exim re-evaluates
760 the load for each incoming message in an SMTP session. Otherwise, once one
761 message is queued, the remainder are also.
763 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
764 cases when an SMTP session ends without sending QUIT. However, when Exim
765 itself is is bad trouble, such as being unable to write to its log files,
766 this ACL is not run, because it might try to do things (such as write to
767 log files) that make the situation even worse.
769 Like the QUIT ACL, this new ACL is provided to make it possible to gather
770 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
771 modifier is forbidden in this ACL.
773 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
774 to a string that indicates the reason for the termination of the SMTP
775 connection. The possible values are:
777 acl-drop Another ACL issued a "drop" command
778 bad-commands Too many unknown or non-mail commands
779 command-timeout Timeout while reading SMTP commands
780 connection-lost The SMTP connection has been lost
781 data-timeout Timeout while reading message data
782 local-scan-error The local_scan() function crashed
783 local-scan-timeout The local_scan() function timed out
784 signal-exit SIGTERM or SIGINT
785 synchronization-error SMTP synchronization error
786 tls-failed TLS failed to start
788 In most cases when an SMTP connection is closed without having received
789 QUIT, Exim sends an SMTP response message before actually closing the
790 connection. With the exception of acl-drop, the default message can be
791 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
792 "drop" verb in another ACL, it is the message from the other ACL that is
795 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
796 servers with individual queries. This is done by starting the query with
797 "servers=x:y:z;", where each item in the list may take one of two forms:
799 (1) If it is just a host name, the appropriate global option (mysql_servers
800 or pgsql_servers) is searched for a host of the same name, and the
801 remaining parameters (database, user, password) are taken from there.
803 (2) If it contains any slashes, it is taken as a complete parameter set.
805 The list of servers is used in exactly the same was as the global list.
806 Once a connection to a server has happened and a query has been
807 successfully executed, processing of the lookup ceases.
809 This feature is intended for use in master/slave situations where updates
810 are occurring, and one wants to update a master rather than a slave. If the
811 masters are in the list for reading, you might have:
813 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
815 In an updating lookup, you could then write
817 ${lookup mysql{servers=master; UPDATE ...}
819 If, on the other hand, the master is not to be used for reading lookups:
821 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
823 you can still update the master by
825 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
827 11. The message_body_newlines option (default FALSE, for backwards
828 compatibility) can be used to control whether newlines are present in
829 $message_body and $message_body_end. If it is FALSE, they are replaced by
836 1. There is a new log selector called smtp_no_mail, which is not included in
837 the default setting. When it is set, a line is written to the main log
838 whenever an accepted SMTP connection terminates without having issued a
841 2. When an item in a dnslists list is followed by = and & and a list of IP
842 addresses, the behaviour was not clear when the lookup returned more than
843 one IP address. This has been solved by the addition of == and =& for "all"
844 rather than the default "any" matching.
846 3. Up till now, the only control over which cipher suites GnuTLS uses has been
847 for the cipher algorithms. New options have been added to allow some of the
848 other parameters to be varied.
850 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
851 set, Exim compiles a runtime option called disable_fsync.
853 5. There is a new variable called $smtp_count_at_connection_start.
855 6. There's a new control called no_pipelining.
857 7. There are two new variables called $sending_ip_address and $sending_port.
858 These are set whenever an SMTP connection to another host has been set up.
860 8. The expansion of the helo_data option in the smtp transport now happens
861 after the connection to the server has been made.
863 9. There is a new expansion operator ${rfc2047d: that decodes strings that
864 are encoded as per RFC 2047.
866 10. There is a new log selector called "pid", which causes the current process
867 id to be added to every log line, in square brackets, immediately after the
870 11. Exim has been modified so that it flushes SMTP output before implementing
871 a delay in an ACL. It also flushes the output before performing a callout,
872 as this can take a substantial time. These behaviours can be disabled by
873 obeying control = no_delay_flush or control = no_callout_flush,
874 respectively, at some earlier stage of the connection.
876 12. There are two new expansion conditions that iterate over a list. They are
877 called forany and forall.
879 13. There's a new global option called dsn_from that can be used to vary the
880 contents of From: lines in bounces and other automatically generated
881 messages ("delivery status notifications" - hence the name of the option).
883 14. The smtp transport has a new option called hosts_avoid_pipelining.
885 15. By default, exigrep does case-insensitive matches. There is now a -I option
886 that makes it case-sensitive.
888 16. A number of new features ("addresses", "map", "filter", and "reduce") have
889 been added to string expansions to make it easier to process lists of
890 items, typically addresses.
892 17. There's a new ACL modifier called "continue". It does nothing of itself,
893 and processing of the ACL always continues with the next condition or
894 modifier. It is provided so that the side effects of expanding its argument
897 18. It is now possible to use newline and other control characters (those with
898 values less than 32, plus DEL) as separators in lists.
900 19. The exigrep utility now has a -v option, which inverts the matching
903 20. The host_find_failed option in the manualroute router can now be set to
910 No new features were added to 4.66.
916 No new features were added to 4.65.
922 1. ACL variables can now be given arbitrary names, as long as they start with
923 "acl_c" or "acl_m" (for connection variables and message variables), are at
924 least six characters long, with the sixth character being either a digit or
927 2. There is a new ACL modifier called log_reject_target. It makes it possible
928 to specify which logs are used for messages about ACL rejections.
930 3. There is a new authenticator called "dovecot". This is an interface to the
931 authentication facility of the Dovecot POP/IMAP server, which can support a
932 number of authentication methods.
934 4. The variable $message_headers_raw provides a concatenation of all the
935 messages's headers without any decoding. This is in contrast to
936 $message_headers, which does RFC2047 decoding on the header contents.
938 5. In a DNS black list, if two domain names, comma-separated, are given, the
939 second is used first to do an initial check, making use of any IP value
940 restrictions that are set. If there is a match, the first domain is used,
941 without any IP value restrictions, to get the TXT record.
943 6. All authenticators now have a server_condition option.
945 7. There is a new command-line option called -Mset. It is useful only in
946 conjunction with -be (that is, when testing string expansions). It must be
947 followed by a message id; Exim loads the given message from its spool
948 before doing the expansions.
950 8. Another similar new command-line option is called -bem. It operates like
951 -be except that it must be followed by the name of a file that contains a
954 9. When an address is delayed because of a 4xx response to a RCPT command, it
955 is now the combination of sender and recipient that is delayed in
956 subsequent queue runs until its retry time is reached.
958 10. Unary negation and the bitwise logical operators and, or, xor, not, and
959 shift, have been added to the eval: and eval10: expansion items.
961 11. The variables $interface_address and $interface_port have been renamed
962 as $received_ip_address and $received_port, to make it clear that they
963 relate to message reception rather than delivery. (The old names remain
964 available for compatibility.)
966 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
967 to vary the message that is sent when an SMTP command is accepted.
973 1. There is a new Boolean option called filter_prepend_home for the redirect
976 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
977 start of receiving a non-SMTP message, before any of the message has been
980 3. When an SMTP error message is specified in a "message" modifier in an ACL,
981 or in a :fail: or :defer: message in a redirect router, Exim now checks the
982 start of the message for an SMTP error code.
984 4. There is a new parameter for LDAP lookups called "referrals", which takes
985 one of the settings "follow" (the default) or "nofollow".
987 5. Version 20070721.2 of exipick now included, offering these new options:
989 After all other sorting options have bee processed, reverse order
990 before displaying messages (-R is synonym).
992 Randomize order of matching messages before displaying.
994 Instead of displaying the matching messages, display the sum
996 --sort <variable>[,<variable>...]
997 Before displaying matching messages, sort the messages according to
998 each messages value for each variable.
1000 Negate the value for every test (returns inverse output from the
1001 same criteria without --not).
1007 1. The ${readsocket expansion item now supports Internet domain sockets as well
1008 as Unix domain sockets. If the first argument begins "inet:", it must be of
1009 the form "inet:host:port". The port is mandatory; it may be a number or the
1010 name of a TCP port in /etc/services. The host may be a name, or it may be an
1011 IP address. An ip address may optionally be enclosed in square brackets.
1012 This is best for IPv6 addresses. For example:
1014 ${readsocket{inet:[::1]:1234}{<request data>}...
1016 Only a single host name may be given, but if looking it up yield more than
1017 one IP address, they are each tried in turn until a connection is made. Once
1018 a connection has been made, the behaviour is as for ${readsocket with a Unix
1021 2. If a redirect router sets up file or pipe deliveries for more than one
1022 incoming address, and the relevant transport has batch_max set greater than
1023 one, a batch delivery now occurs.
1025 3. The appendfile transport has a new option called maildirfolder_create_regex.
1026 Its value is a regular expression. For a maildir delivery, this is matched
1027 against the maildir directory; if it matches, Exim ensures that a
1028 maildirfolder file is created alongside the new, cur, and tmp directories.
1034 The documentation is up-to-date for the 4.61 release. Major new features since
1035 the 4.60 release are:
1037 . An option called disable_ipv6, to disable the use of IPv6 completely.
1039 . An increase in the number of ACL variables to 20 of each type.
1041 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1042 $2, $3, (though those are still set) because the numeric variables get used
1043 for other things in complicated expansions.
1045 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1047 . It is possible to use setclassresources() on some BSD OS to control the
1048 resources used in pipe deliveries.
1050 . A new ACL modifier called add_header, which can be used with any verb.
1052 . More errors are detectable in retry rules.
1054 There are a number of other additions too.
1060 The documentation is up-to-date for the 4.60 release. Major new features since
1061 the 4.50 release are:
1063 . Support for SQLite.
1065 . Support for IGNOREQUOTA in LMTP.
1067 . Extensions to the "submission mode" features.
1069 . Support for Client SMTP Authorization (CSA).
1071 . Support for ratelimiting hosts and users.
1073 . New expansion items to help with the BATV "prvs" scheme.
1075 . A "match_ip" condition, that matches an IP address against a list.
1077 There are many more minor changes.
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