-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.158 2008/02/12 12:52:51 nm4 Exp $
-
New Features in Exim
--------------------
test from the snapshots or the CVS before the documentation is updated. Once
the documentation is updated, this file is reduced to a short list.
-Version 4.70
+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 recieved 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 negociated 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 Recieved-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 ${listcount:string} to count the items in a list.
+
+ 9. New global option "gnutls_enable_pkcs11", defaults false. The GnuTLS
+ rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
+ modules. For some situations this is desirable, but we expect admin in
+ those situations to know they want the feature. More commonly, it means
+ that GUI user modules get loaded and are broken by the setuid Exim being
+ unable to access files specified in environment variables and passed
+ through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
+ unless this new option is set.
+
+10. The "acl = name" condition on an ACL now supports optional arguments.
+ New expansion item "${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 messsage).
+
+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 commandline 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 modifer "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
+------------
+
+ 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
+ ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
+ -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
+
+ 6. There is a new ACL control called "debug", to enable debug logging.
+ This allows selective logging of certain incoming transactions within
+ production environments, with some care. It takes two options, "tag"
+ and "opts"; "tag" is included in the filename of the log and "opts"
+ is used as per the -d<options> command-line option. Examples, which
+ don't all make sense in all contexts:
+
+ control = debug
+ control = debug/tag=.$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<Macro[=Value]> 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 SPF Best Guess support. Documentation for this is in
- experimental-spec.txt.
+ 1. Preliminary DKIM support in Experimental.
Version 4.68
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 smtp_notquit_acl, which is run in most
+ 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
git://git.exim.org / users / heiko / exim.git / blobdiff