This file contains descriptions of new features that have been added to Exim.
Before a formal release, there may be quite a lot of detail so that people can
-test from the snapshots or the CVS before the documentation is updated. Once
+test from the snapshots or the Git before the documentation is updated. Once
the documentation is updated, this file is reduced to a short list.
+Version 4.91
+--------------
+
+ 1. Dual-certificate stacks on servers now support OCSP stapling, under GnuTLS
+ version 3.5.6 or later.
+
+ 2. DANE is now supported under GnuTLS version 3.0.0 or later (adding to the
+ previous OpenSSL implementation, but still Experimental).
+
+ 3. Feature macros for the compiled-in set of malware scanner interfaces.
+
+ 4. SPF support is promoted from Experimental to mainline status. The template
+ src/EDITME makefile does not enable its inclusion.
+
+ 5 Logging control for DKIM verification. The existing DKIM log line is
+ controlled by a "dkim_verbose" selector which is _not_ enabled by default.
+ A new tag "DKIM=<domain>" is added to <= lines by default, controlled by
+ a "dkim" log_selector.
+
+
+Version 4.90
+------------
+
+ 1. PKG_CONFIG_PATH can now be set in Local/Makefile;
+ wildcards will be expanded, values are collapsed.
+
+ 2. The ${readsocket } expansion now takes an option to not shutdown the
+ connection after sending the query string. The default remains to do so.
+
+ 3. An smtp transport option "hosts_noproxy_tls" to control whether multiple
+ deliveries on a single TCP connection can maintain a TLS connection
+ open. By default disabled for all hosts, doing so saves the cost of
+ making new TLS sessions, at the cost of having to proxy the data via
+ another process. Logging is also affected.
+
+ 4. A malware connection type for the FPSCAND protocol.
+
+ 5. An option for recipient verify callouts to hold the connection open for
+ further recipients and for delivery.
+
+ 6. The reproducible build $SOURCE_DATE_EPOCH environment variable is now
+ supported.
+
+ 7. Optionally, an alternate format for spool data-files which matches the
+ wire format - meaning more efficient reception and transmission (at the
+ cost of difficulty with standard Unix tools). Only used for messages
+ received using the ESMTP CHUNKING option, and when a new main-section
+ option "spool_wireformat" (false by default) is set.
+
+ 8. New main configuration option "commandline_checks_require_admin" to
+ restrict who can use various introspection options.
+
+ 9. New option modifier "no_check" for quota and quota_filecount
+ appendfile transport.
+
+10. Variable $smtp_command_history returning a comma-sep list of recent
+ SMTP commands.
+
+11. Millisecond timetamps in logs, on log_selector "millisec". Also affects
+ log elements QT, DT and D, and timstamps in debug output.
+
+12. TCP Fast Open logging. As a server, logs when the SMTP banner was sent
+ while still in SYN_RECV state; as a client logs when the connection
+ is opened with a TFO cookie.
+
+13. DKIM support for multiple signing, by domain and/or key-selector.
+ DKIM support for multiple hashes, and for alternate-identity tags.
+ Builtin macro with default list of signed headers.
+ Better syntax for specifying oversigning.
+ The DKIM ACL can override verification status, and status is visible in
+ the data ACL.
+
+14. Exipick understands -C|--config for an alternative Exim
+ configuration file.
+
+15. TCP Fast Open used, with data-on-SYN, for client SMTP via SOCKS5 proxy,
+ for ${readsocket } expansions, and for ClamAV.
+
+16. The "-be" expansion test mode now supports macros. Macros are expanded
+ in test lines, and new macros can be defined.
+
+17. Support for server-side dual-certificate-stacks (eg. RSA + ECDSA).
+
+
+Version 4.89
+------------
+
+ 1. Allow relative config file names for ".include"
+
+ 2. A main-section config option "debug_store" to control the checks on
+ variable locations during store-reset. Normally false but can be enabled
+ when a memory corrution issue is suspected on a production system.
+
+
+Version 4.88
+------------
+
+ 1. The new perl_taintmode option allows to run the embedded perl
+ interpreter in taint mode.
+
+ 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
+
+ 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
+ modifier.
+
+ 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
+ N can be 224, 256 (default), 384, 512.
+ With GnuTLS 3.5.0 or later, only.
+
+ 5. Facility for named queues: A command-line argument can specify
+ the queue name for a queue operation, and an ACL modifier can set
+ the queue to be used for a message. A $queue_name variable gives
+ visibility.
+
+ 6. New expansion operators base32/base32d.
+
+ 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
+ performance increase and network load decrease. Main config option
+ chunking_advertise_hosts, and smtp transport option hosts_try_chunking
+ for control.
+
+ 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
+
+ 9. Expansion operator escape8bit, like escape but not touching newline etc..
+
+10. Feature macros, generated from compile options. All start with "_HAVE_"
+ and go on with some roughly recognisable name. Driver macros, for
+ router, transport and authentication drivers; names starting with "_DRIVER_".
+ Option macros, for each configuration-file option; all start with "_OPT_".
+ Use the "-bP macros" command-line option to see what is present.
+
+11. Integer values for options can take a "G" multiplier.
+
+12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
+ returns from the target back to the initiator, rather than spooling the
+ message.
+
+13. New built-in constants available for tls_dhparam and default changed.
+
+14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
+ out copies of the message spool files for use by 3rd-party scanners.
+
+15. A new option on the smtp transport, hosts_try_fastopen. If the system
+ supports it (on Linux it must be enabled in the kernel by the sysadmin)
+ try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
+ but it permits a peer that also supports the facility to send its SMTP
+ banner immediately after the SYN,ACK segment rather then waiting for
+ another ACK - so saving up to one roundtrip time. Because it requires
+ previous communication with the peer (we save a cookie from it) this
+ will only become active on frequently-contacted destinations.
+
+16. A new syslog_pid option to suppress PID duplication in syslog lines.
+
+
+Version 4.87
+------------
+
+ 1. The ACL conditions regex and mime_regex now capture substrings
+ into numeric variables $regex1 to 9, like the "match" expansion condition.
+
+ 2. New $callout_address variable records the address used for a spam=,
+ malware= or verify= callout.
+
+ 3. Transports now take a "max_parallel" option, to limit concurrency.
+
+ 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
+ The latter expands to a 8-element colon-sep set of hex digits including
+ leading zeroes. A trailing ipv4-style dotted-decimal set is converted
+ to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
+ The former operator strips leading zeroes and collapses the longest
+ set of 0-groups to a double-colon.
+
+ 5. New "-bP config" support, to dump the effective configuration.
+
+ 6. New $dkim_key_length variable.
+
+ 7. New base64d and base64 expansion items (the existing str2b64 being a
+ synonym of the latter). Add support in base64 for certificates.
+
+ 8. New main configuration option "bounce_return_linesize_limit" to
+ avoid oversize bodies in bounces. The default value matches RFC
+ limits.
+
+ 9. New $initial_cwd expansion variable.
+
+
+Version 4.86
+------------
+
+ 1. Support for using the system standard CA bundle.
+
+ 2. New expansion items $config_file, $config_dir, containing the file
+ and directory name of the main configuration file. Also $exim_version.
+
+ 3. New "malware=" support for Avast.
+
+ 4. New "spam=" variant option for Rspamd.
+
+ 5. Assorted options on malware= and spam= scanners.
+
+ 6. A command-line option to write a comment into the logfile.
+
+ 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
+ be configured to make connections via socks5 proxies.
+
+ 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
+ the transmission of UTF-8 envelope addresses.
+
+ 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
+ used encoding of Maildir folder names.
+
+10. A logging option for slow DNS lookups.
+
+11. New ${env {<variable>}} expansion.
+
+12. A non-SMTP authenticator using information from TLS client certificates.
+
+13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
+ Patch originally by Wolfgang Breyha.
+
+14. Main option "dns_trust_aa" for trusting your local nameserver at the
+ same level as DNSSEC.
+
+
+Version 4.85
+------------
+
+ 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
+ DANE SMTP draft to assess a secure chain of trust of the certificate
+ used to establish the TLS connection based on a TLSA record in the
+ domain of the sender.
+
+ 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
+ and several new events have been created. The reason is because it has
+ been expanded beyond just firing events during the transport phase. Any
+ existing TPDA transport options will have to be rewritten to use a new
+ $event_name expansion variable in a condition. Refer to the
+ experimental-spec.txt for details and examples.
+
+ 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
+ server certs used for TLS match the result of the MX lookup. It does
+ not use the same mechanism as DANE.
+
+
+Version 4.84
+------------
+
+
+Version 4.83
+------------
+
+ 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
+ configured to expect an initial header from a proxy that will make the
+ actual external source IP:host be used in exim instead of the IP of the
+ proxy that is connecting to it.
+
+ 2. New verify option header_names_ascii, which will check to make sure
+ there are no non-ASCII characters in header names. Exim itself handles
+ those non-ASCII characters, but downstream apps may not, so Exim can
+ detect and reject if those characters are present.
+
+ 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
+ codepoints with valid ones.
+
+ 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
+ command line and matching a regex against the return data for trigger
+ and a second regex to extract malware_name. The mail spoolfile name can
+ be included in the command line.
+
+ 5. The smtp transport now supports options "tls_verify_hosts" and
+ "tls_try_verify_hosts". If either is set the certificate verification
+ is split from the encryption operation. The default remains that a failed
+ verification cancels the encryption.
+
+ 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
+ lookup can now set a list of servers to use that is different from the
+ default list.
+
+ 7. New command-line option -C for exiqgrep to specify alternate exim.conf
+ file when searching the queue.
+
+ 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
+
+ 9. Support for DNSSEC on outbound connections.
+
+10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
+ "certextract" to extract fields from them. Hash operators md5 and sha1
+ work over them for generating fingerprints, and a new sha256 operator
+ for them added.
+
+11. PRDR is now supported dy default.
+
+12. OCSP stapling is now supported by default.
+
+13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
+ Delivery Status Notification messages in MIME format, and negotiate
+ DSN features per RFC 3461.
+
+
+Version 4.82
+------------
+
+ 1. New command-line option -bI:sieve will list all supported sieve extensions
+ of this Exim build on standard output, one per line.
+ ManageSieve (RFC 5804) providers managing scripts for use by Exim should
+ query this to establish the correct list to include in the protocol's
+ SIEVE capability line.
+
+ 2. If the -n option is combined with the -bP option, then the name of an
+ emitted option is not output, only the value (if visible to you).
+ For instance, "exim -n -bP pid_file_path" should just emit a pathname
+ followed by a newline, and no other text.
+
+ 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
+ has a "tls_dh_min_bits" option, to set the minimum acceptable number of
+ bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
+ acceptable for security. (Option accepted but ignored if using OpenSSL).
+ Defaults to 1024, the old value. May be lowered only to 512, or raised as
+ far as you like. Raising this may hinder TLS interoperability with other
+ sites and is not currently recommended. Lowering this will permit you to
+ establish a TLS session which is not as secure as you might like.
+
+ Unless you really know what you are doing, leave it alone.
+
+ 4. If not built with DISABLE_DNSSEC, Exim now has the main option
+ dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
+ to send the DO flag to your recursive resolver. If you have a recursive
+ resolver, which can set the Authenticated Data (AD) flag in results, Exim
+ can now detect this. Exim does not perform validation itself, instead
+ relying upon a trusted path to the resolver.
+
+ Current status: work-in-progress; $sender_host_dnssec variable added.
+
+ 5. DSCP support for outbound connections: on a transport using the smtp driver,
+ set "dscp = ef", for instance, to cause the connections to have the relevant
+ DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
+
+ Similarly for inbound connections, there is a new control modifier, dscp,
+ so "warn control = dscp/ef" in the connect ACL, or after authentication.
+
+ Supported values depend upon system libraries. "exim -bI:dscp" to list the
+ ones Exim knows of. You can also set a raw number 0..0x3F.
+
+ 6. The -G command-line flag is no longer ignored; it is now equivalent to an
+ ACL setting "control = suppress_local_fixups". The -L command-line flag
+ is now accepted and forces use of syslog, with the provided tag as the
+ process name. A few other flags used by Sendmail are now accepted and
+ ignored.
+
+ 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
+ ACL modifier; works for single-recipient mails which are received on and
+ deliverable via SMTP. Using the connection made for a recipient verify,
+ if requested before the verify, or a new one made for the purpose while
+ the inbound connection is still active. The bulk of the mail item is copied
+ direct from the inbound socket to the outbound (as well as the spool file).
+ When the source notifies the end of data, the data acceptance by the destination
+ is negotiated before the acceptance is sent to the source. If the destination
+ does not accept the mail item, for example due to content-scanning, the item
+ is not accepted from the source and therefore there is no need to generate
+ a bounce mail. This is of benefit when providing a secondary-MX service.
+ The downside is that delays are under the control of the ultimate destination
+ system not your own.
+
+ The Received-by: header on items delivered by cutthrough is generated
+ early in reception rather than at the end; this will affect any timestamp
+ included. The log line showing delivery is recorded before that showing
+ reception; it uses a new ">>" tag instead of "=>".
+
+ To support the feature, verify-callout connections can now use ESMTP and TLS.
+ The usual smtp transport options are honoured, plus a (new, default everything)
+ hosts_verify_avoid_tls.
+
+ New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
+ for specific access to the information for each connection. The old names
+ are present for now but deprecated.
+
+ Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
+
+ 8. New expansion operators ${listnamed:name} to get the content of a named list
+ and ${listcount:string} to count the items in a list.
+
+ 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
+ rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
+ modules. For some situations this is desirable, but we expect admin in
+ those situations to know they want the feature. More commonly, it means
+ that GUI user modules get loaded and are broken by the setuid Exim being
+ unable to access files specified in environment variables and passed
+ through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
+ unless this new option is set.
+
+ Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
+ so have also added a build option which can be used to build Exim with GnuTLS
+ but without trying to use any kind of PKCS11 support. Uncomment this in the
+ Local/Makefile:
+
+ AVOID_GNUTLS_PKCS11=yes
+
+10. The "acl = name" condition on an ACL now supports optional arguments.
+ New expansion item "${acl {name}{arg}...}" and expansion condition
+ "acl {{name}{arg}...}" are added. In all cases up to nine arguments
+ can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
+ Variable $acl_narg contains the number of arguments. If the ACL sets
+ a "message =" value this becomes the result of the expansion item,
+ or the value of $value for the expansion condition. If the ACL returns
+ accept the expansion condition is true; if reject, false. A defer
+ return results in a forced fail.
+
+11. Routers and transports can now have multiple headers_add and headers_remove
+ option lines. The concatenated list is used.
+
+12. New ACL modifier "remove_header" can remove headers before message gets
+ handled by routers/transports.
+
+13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
+ "aaaa" and "a" lookups is done and the full set of results returned.
+
+14. New expansion variable $headers_added with content from ACL add_header
+ modifier (but not yet added to message).
+
+15. New 8bitmime status logging option for received messages. Log field "M8S".
+
+16. New authenticated_sender logging option, adding to log field "A".
+
+17. New expansion variables $router_name and $transport_name. Useful
+ particularly for debug_print as -bt command-line option does not
+ require privilege whereas -d does.
+
+18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
+ proposed extension to SMTP from Eric Hall.
+
+19. The pipe transport has gained the force_command option, to allow
+ decorating commands from user .forward pipe aliases with prefix
+ wrappers, for instance.
+
+20. Callout connections can now AUTH; the same controls as normal delivery
+ connections apply.
+
+21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
+ options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
+ It adds new expansion variables $dmarc_ar_header, $dmarc_status,
+ $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
+ dmarc_status. It adds new control flags dmarc_disable_verify and
+ dmarc_enable_forensic. The default for the dmarc_tld_file option is
+ "/etc/exim/opendmarc.tlds" and can be changed via EDITME.
+
+22. Add expansion variable $authenticated_fail_id, which is the username
+ provided to the authentication method which failed. It is available
+ for use in subsequent ACL processing (typically quit or notquit ACLs).
+
+23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
+ UDP host and port.
+
+24. New ${hexquote:..string..} expansion operator converts non-printable
+ characters in the string to \xNN form.
+
+25. Experimental TPDA (Transport Post Delivery Action) function added.
+ Patch provided by Axel Rau.
+
+26. Experimental Redis lookup added. Patch provided by Warren Baker.
+
+
Version 4.80
------------
gnutls_require_mac & gnutls_require_protocols are no longer supported.
tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
string, documentation for which is at:
- http://www.gnu.org/software/gnutls/manual/html_node/Priority-Strings.html
+ http://www.gnutls.org/manual/html_node/Priority-Strings.html
SNI support has been added to Exim's GnuTLS integration too.
Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
primes.
+17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
+ Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
+ install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
+
Version 4.77
------------
then henceforth you will have to maintain your own local patches to strip
the safeties off.
- 8. There is a new expansion operator, bool_lax{}. Where bool{} uses the ACL
+ 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
condition logic to determine truth/failure and will fail to expand many
strings, bool_lax{} uses the router condition logic, where most strings
do evaluate true.
Note: bool{00} is false, bool_lax{00} is true.
- 9. Routers now support multiple "condition" tests,
+ 9. Routers now support multiple "condition" tests.
10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
Setting this allows an admin to define which entry in the tcpwrappers
git://git.exim.org / exim.git / blobdiff