4 This file contains descriptions of new features that have been added to Exim.
5 Before a formal release, there may be quite a lot of detail so that people can
6 test from the snapshots or the CVS before the documentation is updated. Once
7 the documentation is updated, this file is reduced to a short list.
12 1. The new perl_taintmode option allows to run the embedded perl
13 interpreter in taint mode.
15 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
17 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
20 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
21 N can be 224, 256 (default), 384, 512.
22 With GnuTLS 3.5.0 or later, only.
24 5. Facility for named queues: A commandline argument can specify
25 the queue name for a queue operation, and an ACL modifier can set
26 the queue to be used for a message. A $queue_name variable gives
29 6. New expansion operators base32/base32d.
31 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
32 performance increase and network load decrease. Main config option
33 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
36 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
38 9. Expansion operator escape8bit, like escape but not touching newline etc..
40 10. Feature macros, generated from compile options. All start with "_HAVE_"
41 and go on with some roughly recognisable name. Driver macros, for
42 router, transport and authentication drivers; names starting with "_DRVR_".
43 Option macros, for each configuration-file option; all start with "_OPT_".
44 Use the "-bP macros" command-line option to see what is present.
46 11. Integer values for options can take a "G" multiplier.
48 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
49 returns from the target back to the initiator, rather than spooling the
52 13. New built-in constants available for tls_dhparam and default changed.
54 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
55 out copies of the message spool files for use by 3rd-party scanners.
57 15. A new option on the smtp transport, hosts_try_fastopen. If the system
58 supports it (on Linux it must be enabled in the kernel by the sysadmin)
59 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
60 but it permits a peer that also supports the facility to send its SMTP
61 banner immediately after the SYN,ACK segment rather then waiting for
62 another ACK - so saving up to one roundtrip time. Because it requires
63 previous communication with the peer (we save a cookie from it) this
64 will only become active on frequently-contected destinations.
70 1. The ACL conditions regex and mime_regex now capture substrings
71 into numeric variables $regex1 to 9, like the "match" expansion condition.
73 2. New $callout_address variable records the address used for a spam=,
74 malware= or verify= callout.
76 3. Transports now take a "max_parallel" option, to limit concurrency.
78 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
79 The latter expands to a 8-element colon-sep set of hex digits including
80 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
81 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
82 The former operator strips leading zeroes and collapses the longest
83 set of 0-groups to a double-colon.
85 5. New "-bP config" support, to dump the effective configuration.
87 6. New $dkim_key_length variable.
89 7. New base64d and base64 expansion items (the existing str2b64 being a
90 synonym of the latter). Add support in base64 for certificates.
92 8. New main configuration option "bounce_return_linesize_limit" to
93 avoid oversize bodies in bounces. The dafault value matches RFC
96 9. New $initial_cwd expansion variable.
102 1. Support for using the system standard CA bundle.
104 2. New expansion items $config_file, $config_dir, containing the file
105 and directory name of the main configuration file. Also $exim_version.
107 3. New "malware=" support for Avast.
109 4. New "spam=" variant option for Rspamd.
111 5. Assorted options on malware= and spam= scanners.
113 6. A commandline option to write a comment into the logfile.
115 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
116 be configured to make connections via socks5 proxies.
118 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
119 the transmission of UTF-8 envelope addresses.
121 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
122 used encoding of Maildir folder names.
124 10. A logging option for slow DNS lookups.
126 11. New ${env {<variable>}} expansion.
128 12. A non-SMTP authenticator using information from TLS client certificates.
130 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
131 Patch originally by Wolfgang Breyha.
133 14. Main option "dns_trust_aa" for trusting your local nameserver at the
134 same level as DNSSEC.
140 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
141 DANE smtp draft to assess a secure chain of trust of the certificate
142 used to establish the TLS connection based on a TLSA record in the
143 domain of the sender.
145 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
146 and several new events have been created. The reason is because it has
147 been expanded beyond just firing events during the transport phase. Any
148 existing TPDA transport options will have to be rewritten to use a new
149 $event_name expansion variable in a condition. Refer to the
150 experimental-spec.txt for details and examples.
152 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
153 server certs used for TLS match the result of the MX lookup. It does
154 not use the same mechanism as DANE.
164 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
165 configured to expect an initial header from a proxy that will make the
166 actual external source IP:host be used in exim instead of the IP of the
167 proxy that is connecting to it.
169 2. New verify option header_names_ascii, which will check to make sure
170 there are no non-ASCII characters in header names. Exim itself handles
171 those non-ASCII characters, but downstream apps may not, so Exim can
172 detect and reject if those characters are present.
174 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
175 codepoints with valid ones.
177 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
178 command line and matching a regex against the return data for trigger
179 and a second regex to extract malware_name. The mail spoolfile name can
180 be included in the command line.
182 5. The smtp transport now supports options "tls_verify_hosts" and
183 "tls_try_verify_hosts". If either is set the certificate verification
184 is split from the encryption operation. The default remains that a failed
185 verification cancels the encryption.
187 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
188 lookup can now set a list of servers to use that is different from the
191 7. New command-line option -C for exiqgrep to specify alternate exim.conf
192 file when searching the queue.
194 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
196 9. Support for DNSSEC on outbound connections.
198 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
199 "certextract" to extract fields from them. Hash operators md5 and sha1
200 work over them for generating fingerprints, and a new sha256 operator
203 11. PRDR is now supported dy default.
205 12. OCSP stapling is now supported by default.
207 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
208 Delivery Status Notification messages in MIME format, and negociate
209 DSN features per RFC 3461.
215 1. New command-line option -bI:sieve will list all supported sieve extensions
216 of this Exim build on standard output, one per line.
217 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
218 query this to establish the correct list to include in the protocol's
219 SIEVE capability line.
221 2. If the -n option is combined with the -bP option, then the name of an
222 emitted option is not output, only the value (if visible to you).
223 For instance, "exim -n -bP pid_file_path" should just emit a pathname
224 followed by a newline, and no other text.
226 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
227 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
228 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
229 acceptable for security. (Option accepted but ignored if using OpenSSL).
230 Defaults to 1024, the old value. May be lowered only to 512, or raised as
231 far as you like. Raising this may hinder TLS interoperability with other
232 sites and is not currently recommended. Lowering this will permit you to
233 establish a TLS session which is not as secure as you might like.
235 Unless you really know what you are doing, leave it alone.
237 4. If not built with DISABLE_DNSSEC, Exim now has the main option
238 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
239 to send the DO flag to your recursive resolver. If you have a recursive
240 resolver, which can set the Authenticated Data (AD) flag in results, Exim
241 can now detect this. Exim does not perform validation itself, instead
242 relying upon a trusted path to the resolver.
244 Current status: work-in-progress; $sender_host_dnssec variable added.
246 5. DSCP support for outbound connections: on a transport using the smtp driver,
247 set "dscp = ef", for instance, to cause the connections to have the relevant
248 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
250 Similarly for inbound connections, there is a new control modifier, dscp,
251 so "warn control = dscp/ef" in the connect ACL, or after authentication.
253 Supported values depend upon system libraries. "exim -bI:dscp" to list the
254 ones Exim knows of. You can also set a raw number 0..0x3F.
256 6. The -G command-line flag is no longer ignored; it is now equivalent to an
257 ACL setting "control = suppress_local_fixups". The -L command-line flag
258 is now accepted and forces use of syslog, with the provided tag as the
259 process name. A few other flags used by Sendmail are now accepted and
262 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
263 ACL modifier; works for single-recipient mails which are recieved on and
264 deliverable via SMTP. Using the connection made for a recipient verify,
265 if requested before the verify, or a new one made for the purpose while
266 the inbound connection is still active. The bulk of the mail item is copied
267 direct from the inbound socket to the outbound (as well as the spool file).
268 When the source notifies the end of data, the data acceptance by the destination
269 is negociated before the acceptance is sent to the source. If the destination
270 does not accept the mail item, for example due to content-scanning, the item
271 is not accepted from the source and therefore there is no need to generate
272 a bounce mail. This is of benefit when providing a secondary-MX service.
273 The downside is that delays are under the control of the ultimate destination
276 The Recieved-by: header on items delivered by cutthrough is generated
277 early in reception rather than at the end; this will affect any timestamp
278 included. The log line showing delivery is recorded before that showing
279 reception; it uses a new ">>" tag instead of "=>".
281 To support the feature, verify-callout connections can now use ESMTP and TLS.
282 The usual smtp transport options are honoured, plus a (new, default everything)
283 hosts_verify_avoid_tls.
285 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
286 for specific access to the information for each connection. The old names
287 are present for now but deprecated.
289 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
291 8. New expansion operators ${listnamed:name} to get the content of a named list
292 and ${listcount:string} to count the items in a list.
294 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
295 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
296 modules. For some situations this is desirable, but we expect admin in
297 those situations to know they want the feature. More commonly, it means
298 that GUI user modules get loaded and are broken by the setuid Exim being
299 unable to access files specified in environment variables and passed
300 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
301 unless this new option is set.
303 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
304 so have also added a build option which can be used to build Exim with GnuTLS
305 but without trying to use any kind of PKCS11 support. Uncomment this in the
308 AVOID_GNUTLS_PKCS11=yes
310 10. The "acl = name" condition on an ACL now supports optional arguments.
311 New expansion item "${acl {name}{arg}...}" and expansion condition
312 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
313 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
314 Variable $acl_narg contains the number of arguments. If the ACL sets
315 a "message =" value this becomes the result of the expansion item,
316 or the value of $value for the expansion condition. If the ACL returns
317 accept the expansion condition is true; if reject, false. A defer
318 return results in a forced fail.
320 11. Routers and transports can now have multiple headers_add and headers_remove
321 option lines. The concatenated list is used.
323 12. New ACL modifier "remove_header" can remove headers before message gets
324 handled by routers/transports.
326 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
327 "aaaa" and "a" lookups is done and the full set of results returned.
329 14. New expansion variable $headers_added with content from ACL add_header
330 modifier (but not yet added to message).
332 15. New 8bitmime status logging option for received messages. Log field "M8S".
334 16. New authenticated_sender logging option, adding to log field "A".
336 17. New expansion variables $router_name and $transport_name. Useful
337 particularly for debug_print as -bt commandline option does not
338 require privilege whereas -d does.
340 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
341 proposed extension to SMTP from Eric Hall.
343 19. The pipe transport has gained the force_command option, to allow
344 decorating commands from user .forward pipe aliases with prefix
345 wrappers, for instance.
347 20. Callout connections can now AUTH; the same controls as normal delivery
350 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
351 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
352 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
353 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
354 dmarc_status. It adds new control flags dmarc_disable_verify and
355 dmarc_enable_forensic.
357 22. Add expansion variable $authenticated_fail_id, which is the username
358 provided to the authentication method which failed. It is available
359 for use in subsequent ACL processing (typically quit or notquit ACLs).
361 23. New ACL modifer "udpsend" can construct a UDP packet to send to a given
364 24. New ${hexquote:..string..} expansion operator converts non-printable
365 characters in the string to \xNN form.
367 25. Experimental TPDA (Transport Post Delivery Action) function added.
368 Patch provided by Axel Rau.
370 26. Experimental Redis lookup added. Patch provided by Warren Baker.
376 1. New authenticator driver, "gsasl". Server-only (at present).
377 This is a SASL interface, licensed under GPL, which can be found at
378 http://www.gnu.org/software/gsasl/.
379 This system does not provide sources of data for authentication, so
380 careful use needs to be made of the conditions in Exim.
382 2. New authenticator driver, "heimdal_gssapi". Server-only.
383 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
384 is no longer honoured for setuid programs by Heimdal. Use the
385 "server_keytab" option to point to the keytab.
387 3. The "pkg-config" system can now be used when building Exim to reference
388 cflags and library information for lookups and authenticators, rather
389 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
390 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
391 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
393 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
394 find the headers and libraries for PCRE.
396 4. New expansion variable $tls_bits.
398 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
399 be joined together with ASCII NUL characters to construct the key to pass
400 into the DBM library. Can be used with gsasl to access sasldb2 files as
403 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
405 Avoid release 1.0.1a if you can. Note that the default value of
406 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
407 increased susceptibility to attack. This may still have interoperability
408 implications for very old clients (see version 4.31 change 37) but
409 administrators can choose to make the trade-off themselves and restore
410 compatibility at the cost of session security.
412 7. Use of the new expansion variable $tls_sni in the main configuration option
413 tls_certificate will cause Exim to re-expand the option, if the client
414 sends the TLS Server Name Indication extension, to permit choosing a
415 different certificate; tls_privatekey will also be re-expanded. You must
416 still set these options to expand to valid files when $tls_sni is not set.
418 The SMTP Transport has gained the option tls_sni, which will set a hostname
419 for outbound TLS sessions, and set $tls_sni too.
421 A new log_selector, +tls_sni, has been added, to log received SNI values
422 for Exim as a server.
424 8. The existing "accept_8bitmime" option now defaults to true. This means
425 that Exim is deliberately not strictly RFC compliant. We're following
426 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
427 Those who disagree, or know that they are talking to mail servers that,
428 even today, are not 8-bit clean, need to turn off this option.
430 9. Exim can now be started with -bw (with an optional timeout, given as
431 -bw<timespec>). With this, stdin at startup is a socket that is
432 already listening for connections. This has a more modern name of
433 "socket activation", but forcing the activated socket to fd 0. We're
434 interested in adding more support for modern variants.
436 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
437 for numbers indicates multiplication by 1024^3.
439 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
440 gnutls_require_mac & gnutls_require_protocols are no longer supported.
441 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
442 string, documentation for which is at:
443 http://www.gnutls.org/manual/html_node/Priority-Strings.html
445 SNI support has been added to Exim's GnuTLS integration too.
447 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
448 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
450 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
451 is now available. If the contents of the file are valid, then Exim will
452 send that back in response to a TLS status request; this is OCSP Stapling.
453 Exim will not maintain the contents of the file in any way: administrators
454 are responsible for ensuring that it is up-to-date.
456 See "experimental-spec.txt" for more details.
458 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
459 identically to TXT record lookups.
461 14. New expansion variable $tod_epoch_l for higher-precision time.
463 15. New global option tls_dh_max_bits, defaulting to current value of NSS
464 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
465 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
467 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
468 Option can now be a path or an identifier for a standard prime.
469 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
470 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
473 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
474 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
475 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
481 1. New options for the ratelimit ACL condition: /count= and /unique=.
482 The /noupdate option has been replaced by a /readonly option.
484 2. The SMTP transport's protocol option may now be set to "smtps", to
485 use SSL-on-connect outbound.
487 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
488 there is a problem talking to the AV scanner, or the AV scanner running.
490 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
491 and check if the search item is a member of the list. This does not
492 support named lists, but does subject the list part to string expansion.
494 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
495 built, Exim no longer performs string expansion on the second string of
496 the match_* expansion conditions: "match_address", "match_domain",
497 "match_ip" & "match_local_part". Named lists can still be used.
503 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
504 or off in the resolver library.
510 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
511 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
512 libraries. The following global options have been added in support of
513 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
514 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
516 2. The pipe transport now takes a boolean option, "freeze_signal", default
517 false. When true, if the external delivery command exits on a signal then
518 Exim will freeze the message in the queue, instead of generating a bounce.
520 3. Log filenames may now use %M as an escape, instead of %D (still available).
521 The %M pattern expands to yyyymm, providing month-level resolution.
523 4. The $message_linecount variable is now updated for the maildir_tag option,
524 in the same way as $message_size, to reflect the real number of lines,
525 including any header additions or removals from transport.
527 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
528 Exim now selects entries randomly, to better scale in a cluster setup.
534 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
535 the flaw permitted the Exim run-time user to cause root to append to
536 arbitrary files of the attacker's choosing, with the content based
537 on content supplied by the attacker.
539 2. Exim now supports loading some lookup types at run-time, using your
540 platform's dlopen() functionality. This has limited platform support
541 and the intention is not to support every variant, it's limited to
542 dlopen(). This permits the main Exim binary to not be linked against
543 all the libraries needed for all the lookup types.
549 NOTE: this version is not guaranteed backwards-compatible, please read the
550 items below carefully
552 1. A new main configuration option, "openssl_options", is available if Exim
553 is built with SSL support provided by OpenSSL. The option allows
554 administrators to specify OpenSSL options to be used on connections;
555 typically this is to set bug compatibility features which the OpenSSL
556 developers have not enabled by default. There may be security
557 consequences for certain options, so these should not be changed
560 2. A new pipe transport option, "permit_coredumps", may help with problem
561 diagnosis in some scenarios. Note that Exim is typically installed as
562 a setuid binary, which on most OSes will inhibit coredumps by default,
563 so that safety mechanism would have to be overridden for this option to
564 be able to take effect.
566 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
567 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
568 Note that this switches Exim to use a new API ("INSTREAM") and a future
569 release of ClamAV will remove support for the old API ("STREAM").
571 The av_scanner option, when set to "clamd", now takes an optional third
572 part, "local", which causes Exim to pass a filename to ClamAV instead of
573 the file content. This is the same behaviour as when clamd is pointed at
574 a Unix-domain socket. For example:
576 av_scanner = clamd:192.0.2.3 1234:local
578 ClamAV's ExtendedDetectionInfo response format is now handled.
580 4. There is now a -bmalware option, restricted to admin users. This option
581 takes one parameter, a filename, and scans that file with Exim's
582 malware-scanning framework. This is intended purely as a debugging aid
583 to ensure that Exim's scanning is working, not to replace other tools.
584 Note that the ACL framework is not invoked, so if av_scanner references
585 ACL variables without a fallback then this will fail.
587 5. There is a new expansion operator, "reverse_ip", which will reverse IP
588 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
590 ${reverse_ip:192.0.2.4}
592 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
593 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
595 6. There is a new ACL control called "debug", to enable debug logging.
596 This allows selective logging of certain incoming transactions within
597 production environments, with some care. It takes two options, "tag"
598 and "opts"; "tag" is included in the filename of the log and "opts"
599 is used as per the -d<options> command-line option. Examples, which
600 don't all make sense in all contexts:
603 control = debug/tag=.$sender_host_address
604 control = debug/opts=+expand+acl
605 control = debug/tag=.$message_exim_id/opts=+expand
607 7. It has always been implicit in the design and the documentation that
608 "the Exim user" is not root. src/EDITME said that using root was
609 "very strongly discouraged". This is not enough to keep people from
610 shooting themselves in the foot in days when many don't configure Exim
611 themselves but via package build managers. The security consequences of
612 running various bits of network code are severe if there should be bugs in
613 them. As such, the Exim user may no longer be root. If configured
614 statically, Exim will refuse to build. If configured as ref:user then Exim
615 will exit shortly after start-up. If you must shoot yourself in the foot,
616 then henceforth you will have to maintain your own local patches to strip
619 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
620 condition logic to determine truth/failure and will fail to expand many
621 strings, bool_lax{} uses the router condition logic, where most strings
623 Note: bool{00} is false, bool_lax{00} is true.
625 9. Routers now support multiple "condition" tests.
627 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
628 Setting this allows an admin to define which entry in the tcpwrappers
629 config file will be used to control access to the daemon. This option
630 is only available when Exim is built with USE_TCP_WRAPPERS. The
631 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
634 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
635 the Exim run-time user, instead of root.
637 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
638 is forced on. This is mitigated by the new build option
639 TRUSTED_CONFIG_LIST which defines a list of configuration files which
640 are trusted; one per line. If a config file is owned by root and matches
641 a pathname in the list, then it may be invoked by the Exim build-time
642 user without Exim relinquishing root privileges.
644 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
645 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
646 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
647 include the main config. As a transition mechanism, we are temporarily
648 providing a work-around: the new build option WHITELIST_D_MACROS provides
649 a colon-separated list of macro names which may be overridden by the Exim
650 run-time user. The values of these macros are constrained to the regex
651 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
657 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
658 writable, the other to locking of MBX folders (not mbox).
660 2. MySQL stored procedures are now supported.
662 3. The dkim_domain transport option is now a list, not a single string, and
663 messages will be signed for each element in the list (discarding
666 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
667 in the presence of multiple character strings within the RR. Prior to 4.70,
668 only the first string would be returned. The dnsdb lookup now, by default,
669 preserves the pre-4.70 semantics, but also now takes an extended output
670 separator specification. The separator can be followed by a semicolon, to
671 concatenate the individual text strings together with no join character,
672 or by a comma and a second separator character, in which case the text
673 strings within a TXT record are joined on that second character.
674 Administrators are reminded that DNS provides no ordering guarantees
675 between multiple records in an RRset. For example:
677 foo.example. IN TXT "a" "b" "c"
678 foo.example. IN TXT "d" "e" "f"
680 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
681 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
682 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
688 1. Native DKIM support without an external library.
689 (Note that if no action to prevent it is taken, a straight upgrade will
690 result in DKIM verification of all signed incoming emails. See spec
691 for details on conditionally disabling)
693 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
695 3. There is now a bool{} expansion condition which maps certain strings to
696 true/false condition values (most likely of use in conjunction with the
697 and{} expansion operator).
699 4. The $spam_score, $spam_bar and $spam_report variables are now available
702 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
703 options, provided that Exim is invoked by an admin_user.
705 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
706 which increases compatibility with older clients at the cost of decreased
707 security. Don't set this unless you need to support such clients.
709 7. There is a new expansion operator, ${randint:...} which will produce a
710 "random" number less than the supplied integer. This randomness is
711 not guaranteed to be cryptographically strong, but depending upon how
712 Exim was built may be better than the most naive schemes.
714 8. Exim now explicitly ensures that SHA256 is available when linked against
717 9. The transport_filter_timeout option now applies to SMTP transports too.
723 1. Preliminary DKIM support in Experimental.
729 1. The body_linecount and body_zerocount C variables are now exported in the
732 2. When a dnslists lookup succeeds, the key that was looked up is now placed
733 in $dnslist_matched. When the key is an IP address, it is not reversed in
734 this variable (though it is, of course, in the actual lookup). In simple
737 deny dnslists = spamhaus.example
739 the key is also available in another variable (in this case,
740 $sender_host_address). In more complicated cases, however, this is not
741 true. For example, using a data lookup might generate a dnslists lookup
744 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
746 If this condition succeeds, the value in $dnslist_matched might be
747 192.168.6.7 (for example).
749 3. Authenticators now have a client_condition option. When Exim is running as
750 a client, it skips an authenticator whose client_condition expansion yields
751 "0", "no", or "false". This can be used, for example, to skip plain text
752 authenticators when the connection is not encrypted by a setting such as:
754 client_condition = ${if !eq{$tls_cipher}{}}
756 Note that the 4.67 documentation states that $tls_cipher contains the
757 cipher used for incoming messages. In fact, during SMTP delivery, it
758 contains the cipher used for the delivery. The same is true for
761 4. There is now a -Mvc <message-id> option, which outputs a copy of the
762 message to the standard output, in RFC 2822 format. The option can be used
763 only by an admin user.
765 5. There is now a /noupdate option for the ratelimit ACL condition. It
766 computes the rate and checks the limit as normal, but it does not update
767 the saved data. This means that, in relevant ACLs, it is possible to lookup
768 the existence of a specified (or auto-generated) ratelimit key without
769 incrementing the ratelimit counter for that key.
771 In order for this to be useful, another ACL entry must set the rate
772 for the same key somewhere (otherwise it will always be zero).
777 # Read the rate; if it doesn't exist or is below the maximum
779 deny ratelimit = 100 / 5m / strict / noupdate
780 log_message = RATE: $sender_rate / $sender_rate_period \
781 (max $sender_rate_limit)
783 [... some other logic and tests...]
785 warn ratelimit = 100 / 5m / strict / per_cmd
786 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
787 (max $sender_rate_limit)
788 condition = ${if le{$sender_rate}{$sender_rate_limit}}
792 6. The variable $max_received_linelength contains the number of bytes in the
793 longest line that was received as part of the message, not counting the
794 line termination character(s).
796 7. Host lists can now include +ignore_defer and +include_defer, analagous to
797 +ignore_unknown and +include_unknown. These options should be used with
798 care, probably only in non-critical host lists such as whitelists.
800 8. There's a new option called queue_only_load_latch, which defaults true.
801 If set false when queue_only_load is greater than zero, Exim re-evaluates
802 the load for each incoming message in an SMTP session. Otherwise, once one
803 message is queued, the remainder are also.
805 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
806 cases when an SMTP session ends without sending QUIT. However, when Exim
807 itself is is bad trouble, such as being unable to write to its log files,
808 this ACL is not run, because it might try to do things (such as write to
809 log files) that make the situation even worse.
811 Like the QUIT ACL, this new ACL is provided to make it possible to gather
812 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
813 modifier is forbidden in this ACL.
815 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
816 to a string that indicates the reason for the termination of the SMTP
817 connection. The possible values are:
819 acl-drop Another ACL issued a "drop" command
820 bad-commands Too many unknown or non-mail commands
821 command-timeout Timeout while reading SMTP commands
822 connection-lost The SMTP connection has been lost
823 data-timeout Timeout while reading message data
824 local-scan-error The local_scan() function crashed
825 local-scan-timeout The local_scan() function timed out
826 signal-exit SIGTERM or SIGINT
827 synchronization-error SMTP synchronization error
828 tls-failed TLS failed to start
830 In most cases when an SMTP connection is closed without having received
831 QUIT, Exim sends an SMTP response message before actually closing the
832 connection. With the exception of acl-drop, the default message can be
833 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
834 "drop" verb in another ACL, it is the message from the other ACL that is
837 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
838 servers with individual queries. This is done by starting the query with
839 "servers=x:y:z;", where each item in the list may take one of two forms:
841 (1) If it is just a host name, the appropriate global option (mysql_servers
842 or pgsql_servers) is searched for a host of the same name, and the
843 remaining parameters (database, user, password) are taken from there.
845 (2) If it contains any slashes, it is taken as a complete parameter set.
847 The list of servers is used in exactly the same was as the global list.
848 Once a connection to a server has happened and a query has been
849 successfully executed, processing of the lookup ceases.
851 This feature is intended for use in master/slave situations where updates
852 are occurring, and one wants to update a master rather than a slave. If the
853 masters are in the list for reading, you might have:
855 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
857 In an updating lookup, you could then write
859 ${lookup mysql{servers=master; UPDATE ...}
861 If, on the other hand, the master is not to be used for reading lookups:
863 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
865 you can still update the master by
867 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
869 11. The message_body_newlines option (default FALSE, for backwards
870 compatibility) can be used to control whether newlines are present in
871 $message_body and $message_body_end. If it is FALSE, they are replaced by
878 1. There is a new log selector called smtp_no_mail, which is not included in
879 the default setting. When it is set, a line is written to the main log
880 whenever an accepted SMTP connection terminates without having issued a
883 2. When an item in a dnslists list is followed by = and & and a list of IP
884 addresses, the behaviour was not clear when the lookup returned more than
885 one IP address. This has been solved by the addition of == and =& for "all"
886 rather than the default "any" matching.
888 3. Up till now, the only control over which cipher suites GnuTLS uses has been
889 for the cipher algorithms. New options have been added to allow some of the
890 other parameters to be varied.
892 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
893 set, Exim compiles a runtime option called disable_fsync.
895 5. There is a new variable called $smtp_count_at_connection_start.
897 6. There's a new control called no_pipelining.
899 7. There are two new variables called $sending_ip_address and $sending_port.
900 These are set whenever an SMTP connection to another host has been set up.
902 8. The expansion of the helo_data option in the smtp transport now happens
903 after the connection to the server has been made.
905 9. There is a new expansion operator ${rfc2047d: that decodes strings that
906 are encoded as per RFC 2047.
908 10. There is a new log selector called "pid", which causes the current process
909 id to be added to every log line, in square brackets, immediately after the
912 11. Exim has been modified so that it flushes SMTP output before implementing
913 a delay in an ACL. It also flushes the output before performing a callout,
914 as this can take a substantial time. These behaviours can be disabled by
915 obeying control = no_delay_flush or control = no_callout_flush,
916 respectively, at some earlier stage of the connection.
918 12. There are two new expansion conditions that iterate over a list. They are
919 called forany and forall.
921 13. There's a new global option called dsn_from that can be used to vary the
922 contents of From: lines in bounces and other automatically generated
923 messages ("delivery status notifications" - hence the name of the option).
925 14. The smtp transport has a new option called hosts_avoid_pipelining.
927 15. By default, exigrep does case-insensitive matches. There is now a -I option
928 that makes it case-sensitive.
930 16. A number of new features ("addresses", "map", "filter", and "reduce") have
931 been added to string expansions to make it easier to process lists of
932 items, typically addresses.
934 17. There's a new ACL modifier called "continue". It does nothing of itself,
935 and processing of the ACL always continues with the next condition or
936 modifier. It is provided so that the side effects of expanding its argument
939 18. It is now possible to use newline and other control characters (those with
940 values less than 32, plus DEL) as separators in lists.
942 19. The exigrep utility now has a -v option, which inverts the matching
945 20. The host_find_failed option in the manualroute router can now be set to
952 No new features were added to 4.66.
958 No new features were added to 4.65.
964 1. ACL variables can now be given arbitrary names, as long as they start with
965 "acl_c" or "acl_m" (for connection variables and message variables), are at
966 least six characters long, with the sixth character being either a digit or
969 2. There is a new ACL modifier called log_reject_target. It makes it possible
970 to specify which logs are used for messages about ACL rejections.
972 3. There is a new authenticator called "dovecot". This is an interface to the
973 authentication facility of the Dovecot POP/IMAP server, which can support a
974 number of authentication methods.
976 4. The variable $message_headers_raw provides a concatenation of all the
977 messages's headers without any decoding. This is in contrast to
978 $message_headers, which does RFC2047 decoding on the header contents.
980 5. In a DNS black list, if two domain names, comma-separated, are given, the
981 second is used first to do an initial check, making use of any IP value
982 restrictions that are set. If there is a match, the first domain is used,
983 without any IP value restrictions, to get the TXT record.
985 6. All authenticators now have a server_condition option.
987 7. There is a new command-line option called -Mset. It is useful only in
988 conjunction with -be (that is, when testing string expansions). It must be
989 followed by a message id; Exim loads the given message from its spool
990 before doing the expansions.
992 8. Another similar new command-line option is called -bem. It operates like
993 -be except that it must be followed by the name of a file that contains a
996 9. When an address is delayed because of a 4xx response to a RCPT command, it
997 is now the combination of sender and recipient that is delayed in
998 subsequent queue runs until its retry time is reached.
1000 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1001 shift, have been added to the eval: and eval10: expansion items.
1003 11. The variables $interface_address and $interface_port have been renamed
1004 as $received_ip_address and $received_port, to make it clear that they
1005 relate to message reception rather than delivery. (The old names remain
1006 available for compatibility.)
1008 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1009 to vary the message that is sent when an SMTP command is accepted.
1015 1. There is a new Boolean option called filter_prepend_home for the redirect
1018 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1019 start of receiving a non-SMTP message, before any of the message has been
1022 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1023 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1024 start of the message for an SMTP error code.
1026 4. There is a new parameter for LDAP lookups called "referrals", which takes
1027 one of the settings "follow" (the default) or "nofollow".
1029 5. Version 20070721.2 of exipick now included, offering these new options:
1031 After all other sorting options have bee processed, reverse order
1032 before displaying messages (-R is synonym).
1034 Randomize order of matching messages before displaying.
1036 Instead of displaying the matching messages, display the sum
1038 --sort <variable>[,<variable>...]
1039 Before displaying matching messages, sort the messages according to
1040 each messages value for each variable.
1042 Negate the value for every test (returns inverse output from the
1043 same criteria without --not).
1049 1. The ${readsocket expansion item now supports Internet domain sockets as well
1050 as Unix domain sockets. If the first argument begins "inet:", it must be of
1051 the form "inet:host:port". The port is mandatory; it may be a number or the
1052 name of a TCP port in /etc/services. The host may be a name, or it may be an
1053 IP address. An ip address may optionally be enclosed in square brackets.
1054 This is best for IPv6 addresses. For example:
1056 ${readsocket{inet:[::1]:1234}{<request data>}...
1058 Only a single host name may be given, but if looking it up yield more than
1059 one IP address, they are each tried in turn until a connection is made. Once
1060 a connection has been made, the behaviour is as for ${readsocket with a Unix
1063 2. If a redirect router sets up file or pipe deliveries for more than one
1064 incoming address, and the relevant transport has batch_max set greater than
1065 one, a batch delivery now occurs.
1067 3. The appendfile transport has a new option called maildirfolder_create_regex.
1068 Its value is a regular expression. For a maildir delivery, this is matched
1069 against the maildir directory; if it matches, Exim ensures that a
1070 maildirfolder file is created alongside the new, cur, and tmp directories.
1076 The documentation is up-to-date for the 4.61 release. Major new features since
1077 the 4.60 release are:
1079 . An option called disable_ipv6, to disable the use of IPv6 completely.
1081 . An increase in the number of ACL variables to 20 of each type.
1083 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1084 $2, $3, (though those are still set) because the numeric variables get used
1085 for other things in complicated expansions.
1087 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1089 . It is possible to use setclassresources() on some BSD OS to control the
1090 resources used in pipe deliveries.
1092 . A new ACL modifier called add_header, which can be used with any verb.
1094 . More errors are detectable in retry rules.
1096 There are a number of other additions too.
1102 The documentation is up-to-date for the 4.60 release. Major new features since
1103 the 4.50 release are:
1105 . Support for SQLite.
1107 . Support for IGNOREQUOTA in LMTP.
1109 . Extensions to the "submission mode" features.
1111 . Support for Client SMTP Authorization (CSA).
1113 . Support for ratelimiting hosts and users.
1115 . New expansion items to help with the BATV "prvs" scheme.
1117 . A "match_ip" condition, that matches an IP address against a list.
1119 There are many more minor changes.
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