New Features in Exim -------------------- 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 Git before the documentation is updated. Once the documentation is updated, this file is reduced to a short list. Version 4.95 ------------ 1. The fast-ramp two phase queue run support, previously experimental, is now supported by default. 2. The native SRS support, previously experimental, is now supported. It is not built unless specified in the Local/Makefile. 3. TLS resumption support, previously experimental, is now supported and included in default builds. 4. Single-key LMDB lookups, previously experimental, are now supported. The support is not built unless specified in the Local/Makefile. 5. Option "message_linelength_limit" on the smtp transport to enforce (by default) the RFC 998 character limit. 6. An option to ignore the cache on a lookup. 7. Quota checking during reception (i.e. at SMTP time) for appendfile- transport-managed quotas. 8. Sqlite lookups accept a "file=" option to specify a per-operation db file, replacing the previous prefix to the SQL string (which had issues when the SQL used tainted values). 9. Lsearch lookups accept a "ret=full" option, to return both the portion of the line matching the key, and the remainder. 10. A command-line option to have a daemon not create a notifier socket. 11. Faster TLS startup. When various configuration options contain no expandable elements, the information can be preloaded and cached rather than the provious behaviour of always loading at startup time for every connection. This helps particularly for the CA bundle. 12. Proxy Protocol Timeout is configurable via "proxy_protocol_timeout" main config option. 13. Option "smtp_accept_msx_per_connection" is now expanded. 13. A main config option "allow_insecure_tainted_data" allows to turn taint errors into warnings. Version 4.94 ------------ 1. EXPERIMENTAL_SRS_NATIVE optional build feature. See the experimental.spec file. 2. Channel-binding for authenticators is now supported under OpenSSL. Previously it was GnuTLS-only. 3. A msg:defer event. 4. Client-side support in the gsasl authenticator. Tested against the plaintext driver for PLAIN; only against itself for SCRAM-SHA-1 and SCRAM-SHA-1-PLUS methods. 5. Server-side support in the gsasl authenticator for encrypted passwords, as an alternate for the existing plaintext. 6. Variable $local_part_data now also set by router check_local_user option, with an de-tainted version of $local_part. 7. Named-list definitions can now be prefixed "hide" so that "-bP" commands do not output the content. Previously this could only be done on options. 8. As an experimental feature, the dovecot authentication driver supports inet sockets. Previously it was unix-domain sockets only. 9. The ACL control "queue_only" can also be spelled "queue", and now takes an option "first_pass_route" to do the same as a "-odqs" on the command line. 10. Items specified for the router and transport headers_remove option can use a trailing asterisk to specify globbing. 11. New $queue_size variable. 12. New variables $local_part_{pre,suf}fix_v. 13. New main option "sqlite_dbfile", for use in preference to prefixing the lookup string. The older method fails when tainted variables are used in the lookup, as the filename becomes tainted. The new method keeps the filename separate. 14. Options on the dsearch lookup, to return the full path and to filter filetypes for matching. 15. Options on pgsql and mysql lookups, to specify server separate from the lookup string. 16. An option on all single-key lookups, to return (on a hit) a de-tainted version of the lookup key rather than the looked-up data. 17. $domain_data and $local_part_data are now set by all list-match successes. Previously only list items that performed lookups did so. Also, matching list items that are tail-match or RE-match now set the numeric variables $0 (etc) in the same way os other RE matches. 18. Expansion item ${listquote {}}. 19. An option for the ${readsocket {}{}{}} expansion to make the result data cacheable. 20. dkim_verify_min_keysizes, a list of minimum acceptable public-key sizes. 21. bounce_message_file and warn_message_file are now expanded before use. 22. New main config option spf_smtp_comment_template to customise the $spf_smtp_comment variable Version 4.93 ------------ 1. An "external" authenticator, per RFC 4422 Appendix A. 2. A JSON lookup type, and JSON variants of the forall/any expansion conditions. 3. Variables $tls_in_cipher_std, $tls_out_cipher_std giving the RFC names for ciphersuites. 4. Log_selectors "msg_id" (on by default) and "msg_id_created". 5. A case_insensitive option for verify=not_blind. 6. EXPERIMENTAL_TLS_RESUME optional build feature. See the experimental.spec file. 7. A main option exim_version to override the version Exim reports in verious places ($exim_version, $version_number). 8. Expansion operator ${sha2_N:} for N=256, 384, 512. 9. Router variables, $r_... settable from router options and usable in routers and transports. 10. The spf lookup now supports IPv6. 11. Main options for DKIM verify to filter hash and key types. 12. With TLS1.3, support for full-chain OCSP stapling. 13. Dual-certificate stacks on servers now support OCSP stapling, under OpenSSL. 14: An smtp:ehlo transport event, for observability of the remote offered features. 15: Support under OpenSSL for writing NSS-style key files for packet-capture decode. The environment variable SSLKEYLOGFILE is used; if an absolute path it must indicate a file under the spool directory; if relative the the spool directory is prepended. Works on the server side only. Support under GnuTLS was already there, being done purely by the library (server side only, and exim must be run as root). 16: Command-line option to move messages from one named queue to another. 17. Variables $tls_in_ver, $tls_out_ver. Version 4.92 -------------- 1. ${l_header:} and ${l_h:} expansion items, giving a colon-sep list when there are multiple headers having a given name. This matters when individual headers are wrapped onto multiple lines; with previous facilities hard to parse. 2. The ${readsocket } expansion item now takes a "tls" option, doing the obvious thing. 3. EXPERIMENTAL_REQUIRETLS and EXPERIMENTAL_PIPE_CONNECT optional build features. See the experimental.spec file. 4. If built with SUPPORT_I18N a "utf8_downconvert" option on the smtp transport. 5. A "pipelining" log_selector. 6. Builtin macros for supported log_selector and openssl_options values. 7. JSON variants of the ${extract } expansion item. 8. A "noutf8" debug option, for disabling the UTF-8 characters in debug output. 9. TCP Fast Open support on MacOS. 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. Both GnuTLS and OpenSSL versions are moved to mainline support from Experimental. New SMTP transport option "dane_require_tls_ciphers". 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=" is added to <= lines by default, controlled by a "dkim" log_selector. 6. Receive duration on <= lines, under a new log_selector "receive_time". 7. Options "ipv4_only" and "ipv4_prefer" on the dnslookup router and on routing rules in the manualroute router. 8. Expansion item ${sha3:} / ${sha3_:} now also supported under OpenSSL version 1.1.1 or later. 9. DKIM operations can now use the Ed25519 algorithm in addition to RSA, under GnuTLS 3.6.0 or OpenSSL 1.1.1 or later. 10. Builtin feature-macros _CRYPTO_HASH_SHA3 and _CRYPTO_SIGN_ED25519, library version dependent. 11. "exim -bP macro " returns caller-usable status. 12. Expansion item ${authresults {}} for creating an Authentication-Results: header. 13. EXPERIMENTAL_ARC. See the experimental.spec file. See also new util/renew-opendmarc-tlds.sh script for use with DMARC/ARC. 14: A dane:fail event, intended to facilitate reporting. 15. "Lightweight" support for Redis Cluster. Requires redis_servers list to contain all the servers in the cluster, all of which must be reachable from the running exim instance. If the cluster has master/slave replication, the list must contain all the master and slave servers. 16. Add an option to the Avast scanner interface: "pass_unscanned". This allows to treat unscanned files as clean. Files may be unscanned for several reasons: decompression bombs, broken archives. 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 corruption 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:} / ${sha3_:}. 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:} and ${ipv6denorm:}. 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 {}} 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 ------------ 1. New authenticator driver, "gsasl". Server-only (at present). This is a SASL interface, licensed under GPL, which can be found at http://www.gnu.org/software/gsasl/. This system does not provide sources of data for authentication, so careful use needs to be made of the conditions in Exim. 2. New authenticator driver, "heimdal_gssapi". Server-only. A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME is no longer honoured for setuid programs by Heimdal. Use the "server_keytab" option to point to the keytab. 3. The "pkg-config" system can now be used when building Exim to reference cflags and library information for lookups and authenticators, rather than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and "LOOKUP_LIBS" directly. Similarly for handling the TLS library support without adjusting "TLS_INCLUDE" and "TLS_LIBS". In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to find the headers and libraries for PCRE. 4. New expansion variable $tls_bits. 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will be joined together with ASCII NUL characters to construct the key to pass into the DBM library. Can be used with gsasl to access sasldb2 files as used by Cyrus SASL. 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1. Avoid release 1.0.1a if you can. Note that the default value of "openssl_options" is no longer "+dont_insert_empty_fragments", as that increased susceptibility to attack. This may still have interoperability implications for very old clients (see version 4.31 change 37) but administrators can choose to make the trade-off themselves and restore compatibility at the cost of session security. 7. Use of the new expansion variable $tls_sni in the main configuration option tls_certificate will cause Exim to re-expand the option, if the client sends the TLS Server Name Indication extension, to permit choosing a different certificate; tls_privatekey will also be re-expanded. You must still set these options to expand to valid files when $tls_sni is not set. The SMTP Transport has gained the option tls_sni, which will set a hostname for outbound TLS sessions, and set $tls_sni too. A new log_selector, +tls_sni, has been added, to log received SNI values for Exim as a server. 8. The existing "accept_8bitmime" option now defaults to true. This means that Exim is deliberately not strictly RFC compliant. We're following Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default. Those who disagree, or know that they are talking to mail servers that, even today, are not 8-bit clean, need to turn off this option. 9. Exim can now be started with -bw (with an optional timeout, given as -bw). With this, stdin at startup is a socket that is already listening for connections. This has a more modern name of "socket activation", but forcing the activated socket to fd 0. We're interested in adding more support for modern variants. 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix for numbers indicates multiplication by 1024^3. 11. The GnuTLS support has been revamped; the three options gnutls_require_kx, 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.gnutls.org/manual/html_node/Priority-Strings.html SNI support has been added to Exim's GnuTLS integration too. For sufficiently recent GnuTLS libraries, ${randint:..} will now use gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness. 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file is now available. If the contents of the file are valid, then Exim will send that back in response to a TLS status request; this is OCSP Stapling. Exim will not maintain the contents of the file in any way: administrators are responsible for ensuring that it is up-to-date. See "experimental-spec.txt" for more details. 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled identically to TXT record lookups. 14. New expansion variable $tod_epoch_l for higher-precision time. 15. New global option tls_dh_max_bits, defaulting to current value of NSS hard-coded limit of DH ephemeral bits, to fix interop problems caused by GnuTLS 2.12 library recommending a bit count higher than NSS supports. 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier. Option can now be a path or an identifier for a standard prime. If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23". 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 ------------ 1. New options for the ratelimit ACL condition: /count= and /unique=. The /noupdate option has been replaced by a /readonly option. 2. The SMTP transport's protocol option may now be set to "smtps", to use SSL-on-connect outbound. 3. New variable $av_failed, set true if the AV scanner deferred; ie, when there is a problem talking to the AV scanner, or the AV scanner running. 4. New expansion conditions, "inlist" and "inlisti", which take simple lists and check if the search item is a member of the list. This does not support named lists, but does subject the list part to string expansion. 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was built, Exim no longer performs string expansion on the second string of the match_* expansion conditions: "match_address", "match_domain", "match_ip" & "match_local_part". Named lists can still be used. Version 4.76 ------------ 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on or off in the resolver library. Version 4.75 ------------ 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there is now LDAP/TLS support, given sufficiently modern OpenLDAP client libraries. The following global options have been added in support of this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key, ldap_cipher_suite, ldap_require_cert, ldap_start_tls. 2. The pipe transport now takes a boolean option, "freeze_signal", default false. When true, if the external delivery command exits on a signal then Exim will freeze the message in the queue, instead of generating a bounce. 3. Log filenames may now use %M as an escape, instead of %D (still available). The %M pattern expands to yyyymm, providing month-level resolution. 4. The $message_linecount variable is now updated for the maildir_tag option, in the same way as $message_size, to reflect the real number of lines, including any header additions or removals from transport. 5. When contacting a pool of SpamAssassin servers configured in spamd_address, Exim now selects entries randomly, to better scale in a cluster setup. Version 4.74 ------------ 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux) the flaw permitted the Exim run-time user to cause root to append to arbitrary files of the attacker's choosing, with the content based on content supplied by the attacker. 2. Exim now supports loading some lookup types at run-time, using your platform's dlopen() functionality. This has limited platform support and the intention is not to support every variant, it's limited to dlopen(). This permits the main Exim binary to not be linked against all the libraries needed for all the lookup types. Version 4.73 ------------ NOTE: this version is not guaranteed backwards-compatible, please read the items below carefully 1. A new main configuration option, "openssl_options", is available if Exim is built with SSL support provided by OpenSSL. The option allows administrators to specify OpenSSL options to be used on connections; typically this is to set bug compatibility features which the OpenSSL developers have not enabled by default. There may be security consequences for certain options, so these should not be changed frivolously. 2. A new pipe transport option, "permit_coredumps", may help with problem diagnosis in some scenarios. Note that Exim is typically installed as a setuid binary, which on most OSes will inhibit coredumps by default, so that safety mechanism would have to be overridden for this option to be able to take effect. 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes Note that this switches Exim to use a new API ("INSTREAM") and a future release of ClamAV will remove support for the old API ("STREAM"). The av_scanner option, when set to "clamd", now takes an optional third part, "local", which causes Exim to pass a filename to ClamAV instead of the file content. This is the same behaviour as when clamd is pointed at a Unix-domain socket. For example: av_scanner = clamd:192.0.2.3 1234:local ClamAV's ExtendedDetectionInfo response format is now handled. 4. There is now a -bmalware option, restricted to admin users. This option takes one parameter, a filename, and scans that file with Exim's malware-scanning framework. This is intended purely as a debugging aid to ensure that Exim's scanning is working, not to replace other tools. Note that the ACL framework is not invoked, so if av_scanner references ACL variables without a fallback then this will fail. 5. There is a new expansion operator, "reverse_ip", which will reverse IP addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples: ${reverse_ip:192.0.2.4} -> 4.2.0.192 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3} -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2 6. There is a new ACL control called "debug", to enable debug logging. This allows selective logging of certain incoming transactions within production environments, with some care. It takes two options, "tag" and "opts"; "tag" is included in the filename of the log and "opts" is used as per the -d command-line option. Examples, which don't all make sense in all contexts: control = debug control = debug/tag=.$sender_host_address control = debug/opts=+expand+acl control = debug/tag=.$message_exim_id/opts=+expand 7. It has always been implicit in the design and the documentation that "the Exim user" is not root. src/EDITME said that using root was "very strongly discouraged". This is not enough to keep people from shooting themselves in the foot in days when many don't configure Exim themselves but via package build managers. The security consequences of running various bits of network code are severe if there should be bugs in them. As such, the Exim user may no longer be root. If configured statically, Exim will refuse to build. If configured as ref:user then Exim will exit shortly after start-up. If you must shoot yourself in the foot, then henceforth you will have to maintain your own local patches to strip the safeties off. 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. 10. There is now a runtime configuration option "tcp_wrappers_daemon_name". Setting this allows an admin to define which entry in the tcpwrappers config file will be used to control access to the daemon. This option is only available when Exim is built with USE_TCP_WRAPPERS. The default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME build option. 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now the Exim run-time user, instead of root. 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and is forced on. This is mitigated by the new build option TRUSTED_CONFIG_LIST which defines a list of configuration files which are trusted; one per line. If a config file is owned by root and matches a pathname in the list, then it may be invoked by the Exim build-time user without Exim relinquishing root privileges. 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically trusted to supply -D overrides on the command-line. Going forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that include the main config. As a transition mechanism, we are temporarily providing a work-around: the new build option WHITELIST_D_MACROS provides a colon-separated list of macro names which may be overridden by the Exim run-time user. The values of these macros are constrained to the regex ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values). Version 4.72 ------------ 1. TWO SECURITY FIXES: one relating to mail-spools which are globally writable, the other to locking of MBX folders (not mbox). 2. MySQL stored procedures are now supported. 3. The dkim_domain transport option is now a list, not a single string, and messages will be signed for each element in the list (discarding duplicates). 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups in the presence of multiple character strings within the RR. Prior to 4.70, only the first string would be returned. The dnsdb lookup now, by default, preserves the pre-4.70 semantics, but also now takes an extended output separator specification. The separator can be followed by a semicolon, to concatenate the individual text strings together with no join character, or by a comma and a second separator character, in which case the text strings within a TXT record are joined on that second character. Administrators are reminded that DNS provides no ordering guarantees between multiple records in an RRset. For example: foo.example. IN TXT "a" "b" "c" foo.example. IN TXT "d" "e" "f" ${lookup dnsdb{>/ txt=foo.example}} -> "a/d" ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc" ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f" Version 4.70 / 4.71 ------------------- 1. Native DKIM support without an external library. (Note that if no action to prevent it is taken, a straight upgrade will result in DKIM verification of all signed incoming emails. See spec for details on conditionally disabling) 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha). 3. There is now a bool{} expansion condition which maps certain strings to true/false condition values (most likely of use in conjunction with the and{} expansion operator). 4. The $spam_score, $spam_bar and $spam_report variables are now available at delivery time. 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as options, provided that Exim is invoked by an admin_user. 6. There is a new option gnutls_compat_mode, when linked against GnuTLS, which increases compatibility with older clients at the cost of decreased security. Don't set this unless you need to support such clients. 7. There is a new expansion operator, ${randint:...} which will produce a "random" number less than the supplied integer. This randomness is not guaranteed to be cryptographically strong, but depending upon how Exim was built may be better than the most naive schemes. 8. Exim now explicitly ensures that SHA256 is available when linked against OpenSSL. 9. The transport_filter_timeout option now applies to SMTP transports too. Version 4.69 ------------ 1. Preliminary DKIM support in Experimental. Version 4.68 ------------ 1. The body_linecount and body_zerocount C variables are now exported in the local_scan API. 2. When a dnslists lookup succeeds, the key that was looked up is now placed in $dnslist_matched. When the key is an IP address, it is not reversed in this variable (though it is, of course, in the actual lookup). In simple cases, for example: deny dnslists = spamhaus.example the key is also available in another variable (in this case, $sender_host_address). In more complicated cases, however, this is not true. For example, using a data lookup might generate a dnslists lookup like this: deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|... If this condition succeeds, the value in $dnslist_matched might be 192.168.6.7 (for example). 3. Authenticators now have a client_condition option. When Exim is running as a client, it skips an authenticator whose client_condition expansion yields "0", "no", or "false". This can be used, for example, to skip plain text authenticators when the connection is not encrypted by a setting such as: client_condition = ${if !eq{$tls_cipher}{}} Note that the 4.67 documentation states that $tls_cipher contains the cipher used for incoming messages. In fact, during SMTP delivery, it contains the cipher used for the delivery. The same is true for $tls_peerdn. 4. There is now a -Mvc option, which outputs a copy of the message to the standard output, in RFC 2822 format. The option can be used only by an admin user. 5. There is now a /noupdate option for the ratelimit ACL condition. It computes the rate and checks the limit as normal, but it does not update the saved data. This means that, in relevant ACLs, it is possible to lookup the existence of a specified (or auto-generated) ratelimit key without incrementing the ratelimit counter for that key. In order for this to be useful, another ACL entry must set the rate for the same key somewhere (otherwise it will always be zero). Example: acl_check_connect: # Read the rate; if it doesn't exist or is below the maximum # we update it below deny ratelimit = 100 / 5m / strict / noupdate log_message = RATE: $sender_rate / $sender_rate_period \ (max $sender_rate_limit) [... some other logic and tests...] warn ratelimit = 100 / 5m / strict / per_cmd log_message = RATE UPDATE: $sender_rate / $sender_rate_period \ (max $sender_rate_limit) condition = ${if le{$sender_rate}{$sender_rate_limit}} accept 6. The variable $max_received_linelength contains the number of bytes in the longest line that was received as part of the message, not counting the line termination character(s). 7. Host lists can now include +ignore_defer and +include_defer, analogous to +ignore_unknown and +include_unknown. These options should be used with care, probably only in non-critical host lists such as whitelists. 8. There's a new option called queue_only_load_latch, which defaults true. If set false when queue_only_load is greater than zero, Exim re-evaluates the load for each incoming message in an SMTP session. Otherwise, once one message is queued, the remainder are also. 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most cases when an SMTP session ends without sending QUIT. However, when Exim itself is is bad trouble, such as being unable to write to its log files, this ACL is not run, because it might try to do things (such as write to log files) that make the situation even worse. Like the QUIT ACL, this new ACL is provided to make it possible to gather statistics. Whatever it returns (accept or deny) is immaterial. The "delay" modifier is forbidden in this ACL. When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set to a string that indicates the reason for the termination of the SMTP connection. The possible values are: acl-drop Another ACL issued a "drop" command bad-commands Too many unknown or non-mail commands command-timeout Timeout while reading SMTP commands connection-lost The SMTP connection has been lost data-timeout Timeout while reading message data local-scan-error The local_scan() function crashed local-scan-timeout The local_scan() function timed out signal-exit SIGTERM or SIGINT synchronization-error SMTP synchronization error tls-failed TLS failed to start In most cases when an SMTP connection is closed without having received QUIT, Exim sends an SMTP response message before actually closing the connection. With the exception of acl-drop, the default message can be overridden by the "message" modifier in the NOTQUIT ACL. In the case of a "drop" verb in another ACL, it is the message from the other ACL that is used. 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of servers with individual queries. This is done by starting the query with "servers=x:y:z;", where each item in the list may take one of two forms: (1) If it is just a host name, the appropriate global option (mysql_servers or pgsql_servers) is searched for a host of the same name, and the remaining parameters (database, user, password) are taken from there. (2) If it contains any slashes, it is taken as a complete parameter set. The list of servers is used in exactly the same was as the global list. Once a connection to a server has happened and a query has been successfully executed, processing of the lookup ceases. This feature is intended for use in master/slave situations where updates are occurring, and one wants to update a master rather than a slave. If the masters are in the list for reading, you might have: mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw In an updating lookup, you could then write ${lookup mysql{servers=master; UPDATE ...} If, on the other hand, the master is not to be used for reading lookups: pgsql_servers = slave1/db/name/pw:slave2/db/name/pw you can still update the master by ${lookup pgsql{servers=master/db/name/pw; UPDATE ...} 11. The message_body_newlines option (default FALSE, for backwards compatibility) can be used to control whether newlines are present in $message_body and $message_body_end. If it is FALSE, they are replaced by spaces. Version 4.67 ------------ 1. There is a new log selector called smtp_no_mail, which is not included in the default setting. When it is set, a line is written to the main log whenever an accepted SMTP connection terminates without having issued a MAIL command. 2. When an item in a dnslists list is followed by = and & and a list of IP addresses, the behaviour was not clear when the lookup returned more than one IP address. This has been solved by the addition of == and =& for "all" rather than the default "any" matching. 3. Up till now, the only control over which cipher suites GnuTLS uses has been for the cipher algorithms. New options have been added to allow some of the other parameters to be varied. 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is set, Exim compiles a runtime option called disable_fsync. 5. There is a new variable called $smtp_count_at_connection_start. 6. There's a new control called no_pipelining. 7. There are two new variables called $sending_ip_address and $sending_port. These are set whenever an SMTP connection to another host has been set up. 8. The expansion of the helo_data option in the smtp transport now happens after the connection to the server has been made. 9. There is a new expansion operator ${rfc2047d: that decodes strings that are encoded as per RFC 2047. 10. There is a new log selector called "pid", which causes the current process id to be added to every log line, in square brackets, immediately after the time and date. 11. Exim has been modified so that it flushes SMTP output before implementing a delay in an ACL. It also flushes the output before performing a callout, as this can take a substantial time. These behaviours can be disabled by obeying control = no_delay_flush or control = no_callout_flush, respectively, at some earlier stage of the connection. 12. There are two new expansion conditions that iterate over a list. They are called forany and forall. 13. There's a new global option called dsn_from that can be used to vary the contents of From: lines in bounces and other automatically generated messages ("delivery status notifications" - hence the name of the option). 14. The smtp transport has a new option called hosts_avoid_pipelining. 15. By default, exigrep does case-insensitive matches. There is now a -I option that makes it case-sensitive. 16. A number of new features ("addresses", "map", "filter", and "reduce") have been added to string expansions to make it easier to process lists of items, typically addresses. 17. There's a new ACL modifier called "continue". It does nothing of itself, and processing of the ACL always continues with the next condition or modifier. It is provided so that the side effects of expanding its argument can be used. 18. It is now possible to use newline and other control characters (those with values less than 32, plus DEL) as separators in lists. 19. The exigrep utility now has a -v option, which inverts the matching condition. 20. The host_find_failed option in the manualroute router can now be set to "ignore". Version 4.66 ------------ No new features were added to 4.66. Version 4.65 ------------ No new features were added to 4.65. Version 4.64 ------------ 1. ACL variables can now be given arbitrary names, as long as they start with "acl_c" or "acl_m" (for connection variables and message variables), are at least six characters long, with the sixth character being either a digit or an underscore. 2. There is a new ACL modifier called log_reject_target. It makes it possible to specify which logs are used for messages about ACL rejections. 3. There is a new authenticator called "dovecot". This is an interface to the authentication facility of the Dovecot POP/IMAP server, which can support a number of authentication methods. 4. The variable $message_headers_raw provides a concatenation of all the messages's headers without any decoding. This is in contrast to $message_headers, which does RFC2047 decoding on the header contents. 5. In a DNS black list, if two domain names, comma-separated, are given, the second is used first to do an initial check, making use of any IP value restrictions that are set. If there is a match, the first domain is used, without any IP value restrictions, to get the TXT record. 6. All authenticators now have a server_condition option. 7. There is a new command-line option called -Mset. It is useful only in conjunction with -be (that is, when testing string expansions). It must be followed by a message id; Exim loads the given message from its spool before doing the expansions. 8. Another similar new command-line option is called -bem. It operates like -be except that it must be followed by the name of a file that contains a message. 9. When an address is delayed because of a 4xx response to a RCPT command, it is now the combination of sender and recipient that is delayed in subsequent queue runs until its retry time is reached. 10. Unary negation and the bitwise logical operators and, or, xor, not, and shift, have been added to the eval: and eval10: expansion items. 11. The variables $interface_address and $interface_port have been renamed as $received_ip_address and $received_port, to make it clear that they relate to message reception rather than delivery. (The old names remain available for compatibility.) 12. The "message" modifier can now be used on "accept" and "discard" acl verbs to vary the message that is sent when an SMTP command is accepted. Version 4.63 ------------ 1. There is a new Boolean option called filter_prepend_home for the redirect router. 2. There is a new acl, set by acl_not_smtp_start, which is run right at the start of receiving a non-SMTP message, before any of the message has been read. 3. When an SMTP error message is specified in a "message" modifier in an ACL, or in a :fail: or :defer: message in a redirect router, Exim now checks the start of the message for an SMTP error code. 4. There is a new parameter for LDAP lookups called "referrals", which takes one of the settings "follow" (the default) or "nofollow". 5. Version 20070721.2 of exipick now included, offering these new options: --reverse After all other sorting options have bee processed, reverse order before displaying messages (-R is synonym). --random Randomize order of matching messages before displaying. --size Instead of displaying the matching messages, display the sum of their sizes. --sort [,...] Before displaying matching messages, sort the messages according to each messages value for each variable. --not Negate the value for every test (returns inverse output from the same criteria without --not). Version 4.62 ------------ 1. The ${readsocket expansion item now supports Internet domain sockets as well as Unix domain sockets. If the first argument begins "inet:", it must be of the form "inet:host:port". The port is mandatory; it may be a number or the name of a TCP port in /etc/services. The host may be a name, or it may be an IP address. An ip address may optionally be enclosed in square brackets. This is best for IPv6 addresses. For example: ${readsocket{inet:[::1]:1234}{}... Only a single host name may be given, but if looking it up yield more than one IP address, they are each tried in turn until a connection is made. Once a connection has been made, the behaviour is as for ${readsocket with a Unix domain socket. 2. If a redirect router sets up file or pipe deliveries for more than one incoming address, and the relevant transport has batch_max set greater than one, a batch delivery now occurs. 3. The appendfile transport has a new option called maildirfolder_create_regex. Its value is a regular expression. For a maildir delivery, this is matched against the maildir directory; if it matches, Exim ensures that a maildirfolder file is created alongside the new, cur, and tmp directories. Version 4.61 ------------ The documentation is up-to-date for the 4.61 release. Major new features since the 4.60 release are: . An option called disable_ipv6, to disable the use of IPv6 completely. . An increase in the number of ACL variables to 20 of each type. . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1, $2, $3, (though those are still set) because the numeric variables get used for other things in complicated expansions. . The default for rfc1413_query_timeout has been changed from 30s to 5s. . It is possible to use setclassresources() on some BSD OS to control the resources used in pipe deliveries. . A new ACL modifier called add_header, which can be used with any verb. . More errors are detectable in retry rules. There are a number of other additions too. Version 4.60 ------------ The documentation is up-to-date for the 4.60 release. Major new features since the 4.50 release are: . Support for SQLite. . Support for IGNOREQUOTA in LMTP. . Extensions to the "submission mode" features. . Support for Client SMTP Authorization (CSA). . Support for ratelimiting hosts and users. . New expansion items to help with the BATV "prvs" scheme. . A "match_ip" condition, that matches an IP address against a list. There are many more minor changes. ****