-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.117 2006/10/16 15:44:36 ph10 Exp $
+$Cambridge: exim/doc/doc-txt/NewStuff,v 1.176 2010/06/14 18:51:10 pdp Exp $
New Features in Exim
--------------------
the documentation is updated, this file is reduced to a short list.
+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 overriden 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 operator, 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_PREFIX_LIST which defines a list of pathname prefices which
+ are trusted; if a config file is owned by root and is under that prefix,
+ then it may be used by the Exim run-time user.
+
+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_PREFIX_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 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 <message-id> 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, analagous 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. The rest of the name can contain alphanumeric characters
- and underscores. This is a compatible change because the old set of
- variables such as acl_m12 are a subset of the allowed names. There may now
- be any number of ACL variables. For example:
-
- set acl_c13 = value for original ACL variable
- set acl_c13b = whatever
- set acl_m_foo = something
-
- What happens if a syntactically valid but undefined ACL variable is
- referenced depends on the setting of the strict_acl_vars option. If it is
- false (the default), an empty string is substituted; if it is true, an error
- is generated. This affects all ACL variables, including the "old" ones such
- as acl_c4. (Previously there wasn't the concept of an undefined ACL
- variable.)
-
- The implementation has been done in such a way that spool files containing
- ACL variable settings written by previous releases of Exim are compatible
- and can be read by the new release. If only the original numeric names are
- used, spool files written by the new release can be read by earlier
- releases.
-
-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. Its
- argument is a list of words which can be "main", "reject", or "panic". The
- default is "main:reject". The list may be empty, in which case a rejection
- is not logged at all. For example, this ACL fragment writes no logging
- information when access is denied:
-
- deny <some conditions>
- log_reject_target =
-
- The modifier can be used in SMTP and non-SMTP ACLs. It applies to both
- permanent and temporary 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. If you are using Dovecot to authenticate
- POP/IMAP clients, it might be helpful to use the same mechanisms for SMTP
- authentication. This is a server authenticator only. The only option is
- server_socket, which must specify the socket which is the interface to
- Dovecot authentication. The public_name option must specify an
- authentication mechanism that Dovecot is configured to support. You can have
- several authenticators for different mechanisms. For example:
-
- dovecot_plain:
- driver = dovecot
- public_name = PLAIN
- server_name = /var/run/dovecot/auth-client
- server_setid = $auth1
-
- dovecot_ntlm:
- driver = dovecot
- public_name = NTLM
- server_name = /var/run/dovecot/auth-client
- server_setid = $auth1
-
- If the SMTP connection is encrypted, or if $sender_host_address is equal to
- $interface_address (that is, the connection is local), the "secured" option
- is passed in the Dovecot authentication command. If, for a TLS connection, a
- client certificate has been verified, the "valid-client-cert" option is
- passed.
-
-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, when the facility for restricting the matching IP
- values is used, the text from the TXT record that is set in $dnslist_text
- may not reflect the true reason for rejection. This happens when lists are
- merged and the IP address in the A record is used to distinguish them;
- unfortunately there is only one TXT record. One way round this is not to use
- merged lists, but that can be inefficient because it requires multiple DNS
- lookups where one would do in the vast majority of cases when the host of
- interest is not on any of the lists.
-
- A less inefficient way of solving this problem has now been implemented. 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. As a byproduct of this, there is also a
- check that the IP being tested is indeed on the first list. The first domain
- is the one that is put in $dnslist_domain. For example:
-
- reject message = rejected because $sender_ip_address is blacklisted \
- at $dnslist_domain\n$dnslist_text
- dnslists = sbl.spamhaus.org,sbl-xbl.spamhaus.org=127.0.0.2 : \
- dul.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.10
-
- For the first blacklist item, this starts by doing a lookup in
- sbl-xbl.spamhaus.org and testing for a 127.0.0.2 return. If there is a
- match, it then looks in sbl.spamhaus.org, without checking the return value,
- and as long as something is found, it looks for the corresponding TXT
- record. If there is no match in sbl-xbl.spamhaus.org, nothing more is done.
- The second blacklist item is processed similarly.
-
- If you are interested in more than one merged list, the same list must be
- given several times, but because the results of the DNS lookups are cached,
- the DNS calls themselves are not repeated. For example:
-
- reject dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
- socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3 : \
- misc.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.4 : \
- dul.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.10
-
- In this case there is a lookup in dnsbl.sorbs.net, and if none of the IP
- values matches (or if no record is found), this is the only lookup that is
- done. Only if there is a match is one of the more specific lists consulted.
-
-6. All authenticators now have a server_condition option. Previously, only
- plaintext had this, and this has not changed: it must be set to the
- authenticator as a server. For the others, if server_condition is set, it is
- expanded if authentication is successful, and treated exactly as it is in
- plaintext. This can serve as a means of adding authorization to an
- authenticator.
+ 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
git://git.exim.org / users / heiko / exim.git / blobdiff