-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.176 2010/06/14 18:51:10 pdp Exp $
-
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 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 4.89
+------------
+
+ 1. Allow relative config file names for ".include"
+
+
+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.
+
+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<timespec>). 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 $message_size, to reflect the real number of lines,
+ including any header additions or removals from transport.
+
+ 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
+ Exim now selects entries randomly, to better scale in a cluster setup.
+
Version 4.74
------------
2. A new pipe transport option, "permit_coredumps", may help with problem
diagnosis in some scenarios. Note that Exim is typically installed as
a setuid binary, which on most OSes will inhibit coredumps by default,
- so that safety mechanism would have to be overriden for this option to
+ so that safety mechanism would have to be overridden for this option to
be able to take effect.
3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
then henceforth you will have to maintain your own local patches to strip
the safeties off.
- 8. There is a new expansion operator, bool_lax{}. Where bool{} uses the ACL
+ 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
condition logic to determine truth/failure and will fail to expand many
strings, bool_lax{} uses the router condition logic, where most strings
do evaluate true.
Note: bool{00} is false, bool_lax{00} is true.
- 9. Routers now support multiple "condition" tests,
+ 9. Routers now support multiple "condition" tests.
10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
Setting this allows an admin to define which entry in the tcpwrappers
forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
include the main config. As a transition mechanism, we are temporarily
providing a work-around: the new build option WHITELIST_D_MACROS provides
- a colon-separated list of macro names which may be overriden by the Exim
+ a colon-separated list of macro names which may be overridden by the Exim
run-time user. The values of these macros are constrained to the regex
^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
git://git.exim.org / users / jgh / exim.git / blobdiff