-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.141 2007/02/14 14:59:01 ph10 Exp $
+$Cambridge: exim/doc/doc-txt/NewStuff,v 1.160 2009/11/14 20:35:55 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 4.67
+Version 4.71
------------
- 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. This includes both the case when the connection is dropped,
- and the case when QUIT is used. Note that it does not include cases where
- the connection is rejected right at the start (by an ACL, or because there
- are too many connections, or whatever). These cases already have their own
- log lines.
-
- The log line that is written contains the identity of the client in the
- usual way, followed by D= and a time, which records the duration of the
- connection. If the connection was authenticated, this fact is logged
- exactly as it is for an incoming message, with an A= item. If the
- connection was encrypted, CV=, DN=, and X= items may appear as they do for
- an incoming message, controlled by the same logging options.
-
- Finally, if any SMTP commands were issued during the connection, a C= item
- is added to the line, listing the commands that were used. For example,
-
- C=EHLO,QUIT
-
- shows that the client issued QUIT straight after EHLO. If there were fewer
- than 20 commands, they are all listed. If there were more than 20 commands,
- the last 20 are listed, preceded by "...". However, with the default
- setting of 10 for smtp_accep_max_nonmail, the connection will in any case
- be aborted before 20 non-mail commands are processed.
-
- 2. When an item in a dnslists list is followed by = and & and a list of IP
- addresses, in order to restrict the match to specific results from the DNS
- lookup, the behaviour was not clear when the lookup returned more than one
- IP address. For example, consider the condition
-
- dnslists = a.b.c=127.0.0.1
-
- What happens if the DNS lookup for the incoming IP address yields both
- 127.0.0.1 and 127.0.0.2 by means of two separate DNS records? Is the
- condition true because at least one given value was found, or is it false
- because at least one of the found values was not listed? And how does this
- affect negated conditions?
-
- The behaviour of = and & has not been changed; however, the text below
- documents it more clearly. In addition, two new additional conditions (==
- and =&) have been added, to permit the "other" behaviour to be configured.
-
- A DNS lookup may yield more than one record. Thus, the result of the lookup
- for a dnslists check may yield more than one IP address. The question then
- arises as to whether all the looked up addresses must be listed, or whether
- just one is good enough. Both possibilities are provided for:
-
- . If = or & is used, the condition is true if any one of the looked up
- IP addresses matches one of the listed addresses. Consider:
-
- dnslists = a.b.c=127.0.0.1
-
- If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is
- true because 127.0.0.1 matches.
-
- . If == or =& is used, the condition is true only if every one of the
- looked up IP addresses matches one of the listed addresses. Consider:
+Version 4.70
+------------
- dnslists = a.b.c==127.0.0.1
+ 1. Native DKIM support without an external library.
- If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is
- false because 127.0.0.2 is not listed. You would need to have
+ 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
- dnslists = a.b.c==127.0.0.1,127.0.0.2
- for the condition to be true.
+Version 4.68
+------------
- When ! is used to negate IP address matching, it inverts the result, giving
- the precise opposite of the behaviour above. Thus:
+ 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.
- . If != or !& is used, the condition is true if none of the looked up IP
- addresses matches one of the listed addresses. Consider:
+ 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.
- dnslists = a.b.c!&0.0.0.1
+ 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.
- If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is
- false because 127.0.0.1 matches.
+ 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).
- . If !== or !=& is used, the condition is true there is at least one looked
- up IP address that does not match. Consider:
+ Example:
- dnslists = a.b.c!=&0.0.0.1
+ 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)
- If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is
- true, because 127.0.0.2 does not match. You would need to have
+ [... some other logic and tests...]
- dnslists = a.b.c!=&0.0.0.1,0.0.0.2
+ 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}}
- for the condition to be false.
+ accept
- When the DNS lookup yields only a single IP address, there is no difference
- between = and == and between & and =&.
+ 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).
- 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. Here is complete documentation for the
- available features:
-
- GnuTLS allows the caller to specify separate lists of permitted key
- exchange methods, main cipher algorithms, and MAC algorithms. These may be
- used in any combination to form a specific cipher suite. This is unlike
- OpenSSL, where complete cipher names can be passed to its control function.
- GnuTLS also allows a list of acceptable protocols to be supplied.
-
- For compatibility with OpenSSL, the tls_require_ciphers option can be set
- to complete cipher suite names such as RSA_ARCFOUR_SHA, but for GnuTLS this
- option controls only the cipher algorithms. Exim searches each item in the
- list for the name of an available algorithm. For example, if the list
- contains RSA_AES_SHA, then AES is recognized, and the behaviour is exactly
- the same as if just AES were given.
-
- There are additional options called gnutls_require_kx, gnutls_require_mac,
- and gnutls_require_protocols that can be used to restrict the key exchange
- methods, MAC algorithms, and protocols, respectively. These options are
- ignored if OpenSSL is in use.
-
- All four options are available as global options, controlling how Exim
- behaves as a server, and also as options of the smtp transport, controlling
- how Exim behaves as a client. All the values are string expanded. After
- expansion, the values must be colon-separated lists, though the separator
- can be changed in the usual way.
-
- Each of the four lists starts out with a default set of algorithms. If the
- first item in one of the "require" options does _not_ start with an
- exclamation mark, all the default items are deleted. In this case, only
- those that are explicitly specified can be used. If the first item in one
- of the "require" items _does_ start with an exclamation mark, the defaults
- are left on the list.
-
- Then, any item that starts with an exclamation mark causes the relevant
- entry to be removed from the list, and any item that does not start with an
- exclamation mark causes a new entry to be added to the list. Unrecognized
- items in the list are ignored. Thus:
-
- tls_require_ciphers = !ARCFOUR
-
- allows all the defaults except ARCFOUR, whereas
-
- tls_require_ciphers = AES : 3DES
-
- allows only cipher suites that use AES or 3DES. For tls_require_ciphers
- the recognized names are AES_256, AES_128, AES (both of the preceding),
- 3DES, ARCFOUR_128, ARCFOUR_40, and ARCFOUR (both of the preceding). The
- default list does not contain all of these; it just has AES_256, AES_128,
- 3DES, and ARCFOUR_128.
-
- For gnutls_require_kx, the recognized names are DHE_RSA, RSA (which
- includes DHE_RSA), DHE_DSS, and DHE (which includes both DHE_RSA and
- DHE_DSS). The default list contains RSA, DHE_DSS, DHE_RSA.
-
- For gnutls_require_mac, the recognized names are SHA (synonym SHA1), and
- MD5. The default list contains SHA, MD5.
-
- For gnutls_require_protocols, the recognized names are TLS1 and SSL3.
- The default list contains TLS1, SSL3.
-
- In a server, the order of items in these lists is unimportant. The server
- will advertise the availability of all the relevant cipher suites. However,
- in a client, the order in the tls_require_ciphers list specifies a
- preference order for the cipher algorithms. The first one in the client's
- list that is also advertised by the server is tried first.
-
- 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. You must
- not set this option unless you really, really, really understand what you
- are doing. No pre-compiled distributions of Exim should ever set this
- option. When it is set, Exim compiles a runtime option called
- disable_fsync. If this is set true, Exim no longer calls fsync() to force
- updated files' data to be written to disc. Unexpected events such as
- crashes and power outages may cause data to be lost or scrambled. Beware.
-
- When ENABLE_DISABLE_FSYNC is not set, a reference to disable_fsync in a
- runtime configuration generates an "unknown option" error.
-
- 5. There is a new variable called $smtp_count_at_connection_start. The name
- is deliberately long, in order to emphasize what the contents are. This
- variable is set greater than zero only in processes spawned by the Exim
- daemon for handling incoming SMTP connections. When the daemon accepts a
- new connection, it increments this variable. A copy of the variable is
- passed to the child process that handles the connection, but its value is
- fixed, and never changes. It is only an approximation of how many incoming
- connections there actually are, because many other connections may come and
- go while a single connection is being processed. When a child process
- terminates, the daemon decrements the variable.
-
- 6. There's a new control called no_pipelining, which does what its name
- suggests. It turns off the advertising of the PIPELINING extension to SMTP.
- To be useful, this control must be obeyed before Exim sends its response to
- an EHLO command. Therefore, it should normally appear in an ACL controlled
- by acl_smtp_connect or acl_smtp_helo.
+ 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.
- 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,
- and they contain the IP address and port of the local interface that is
- being used. They are of interest only on hosts that have more than on IP
- address that want to take on different personalities depending on which one
- is being used.
+ 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.
- 8. The expansion of the helo_data option in the smtp transport now happens
- after the connection to the server has been made. This means that it can
- use the value of $sending_ip_address (see 7 above) to vary the text of the
- message. For example, if you want the string that is used for helo_data to
- be obtained by a DNS lookup of the interface address, you could use this:
+ 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.
- helo_data = ${lookup dnsdb{ptr=$sending_ip_address}{$value}\
- {$primary_hostname}}
+ 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.
- The use of helo_data applies both to sending messages and when doing
- callouts.
+ 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:
- 9. There is a new expansion operator ${rfc2047d: that decodes strings that
- are encoded as per RFC 2047. Binary zero bytes are replaced by question
- marks. Characters are converted into the character set defined by
- headers_charset. Overlong RFC 2047 "words" are not recognized unless
- check_rfc2047_length is set false.
+ 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
-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.
+ 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.
-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. The effect of the
- new default behaviour is to disable the PIPELINING optimization in these
- situations, in order to avoid unexpected timeouts in clients.
+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:
-12. There are two new expansion conditions that iterate over a list. They are
- called forany and forall, and they are used like this:
+ (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.
- ${if forany{<a list>}{<a condition>}{<yes-string>}{<no-string>}}
- ${if forall{<a list>}{<a condition>}{<yes-string>}{<no-string>}}
+ (2) If it contains any slashes, it is taken as a complete parameter set.
- The first argument is expanded, and the result is treated as a list. By
- default, the list separator is a colon, but it can be changed by the normal
- method. The second argument is interpreted as a condition that is to be
- applied to each item in the list in turn. During the interpretation of the
- condition, the current list item is placed in a variable called $item.
+ 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.
- - For forany, interpretation stops if the condition is true for any item,
- and the yes-string is then expanded. If the condition is false for all
- items in the list, the no-string is expanded.
+ 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:
- - For forall, interpration stops if the condition is false for any item,
- and the no-string is then expanded. If the condition is true for all
- items in the list, the yes-string is expanded.
+ mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
- Note that negation of forany means that the condition must be false for all
- items for the overall condition to succeed, and negation of forall means
- that the condition must be false for at least one item.
+ In an updating lookup, you could then write
- In this example, the list separator is changed to a comma:
+ ${lookup mysql{servers=master; UPDATE ...}
- ${if forany{<, $recipients}{match{$item}{^user3@}}{yes}{no}}
+ If, on the other hand, the master is not to be used for reading lookups:
- Outside a forany/forall condition, the value of $item is an empty string.
- Its value is saved and restored while forany/forall is being processed, to
- enable these expansion items to be nested.
+ pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
-13. There's a new global option called dsn_from that can be used to vary the
- contents of From: lines in bounces and other automatically generated
- messages ("delivery status notifications" - hence the name of the option).
- The default setting is:
+ you can still update the master by
- dsn_from = Mail Delivery System <Mailer-Daemon@$qualify_domain>
+ ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
- The value is expanded every time it is needed. If the expansion fails, a
- panic is logged, and the default setting is used.
+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.
-14. The smtp transport has a new option called hosts_avoid_pipelining. It can
- be used to suppress the use of PIPELINING to certain hosts, while still
- supporting the other SMTP extensions (cf hosts_avoid_tls).
-15. By default, exigrep does case-insensitive matches. There is now a -I option
- that makes it case-sensitive. This may give a performance improvement when
- searching large log files. Without -I, the Perl pattern matches use the /i
- option; with -I they don't. In both cases it is possible to change the case
- sensitivity within the pattern using (?i) or (?-i).
+Version 4.67
+------------
-14. A number of new features have been added to string expansions to make it
- easier to process lists of items, typically addresses. These are as
- follows:
+ 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.
- * ${addresses:<string>}
+ 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.
- The string (after expansion) is interpreted as a list of addresses in RFC
- 2822 format, such as can be found in a To: or Cc: header line. The
- operative address (local-part@domain) is extracted from each item, and the
- result of the expansion is a colon-separated list, with appropriate
- doubling of colons should any happen to be present in the email addresses.
- Syntactically invalid RFC2822 address items are omitted from the output.
+ 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.
- It is possible to specify a character other than colon for the output
- separator by starting the string with > followed by the new separator
- character. For example:
+ 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
+ set, Exim compiles a runtime option called disable_fsync.
- ${addresses:>& The Boss <ceo@up.stairs>, sec@base.ment (dogsbody)}
+ 5. There is a new variable called $smtp_count_at_connection_start.
- expands to "ceo@up.stairs&sec@base.ment". Compare ${address (singular),
- which extracts the working address from a single RFC2822 address.
+ 6. There's a new control called no_pipelining.
- * ${map{<string1>}{<string2>}}
+ 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.
- After expansion, <string1> is interpreted as a list, colon-separated by
- default, but the separator can be changed in the usual way. For each item
- in this list, its value is place in $item, and then <string2> is expanded
- and added to the output as an item in a new list. The separator used for
- the output list is the same as the one used for the input, but is not
- included in the output. For example:
+ 8. The expansion of the helo_data option in the smtp transport now happens
+ after the connection to the server has been made.
- ${map{a:b:c}{[$item]}} ${map{<- x-y-z}{($item)}}
+ 9. There is a new expansion operator ${rfc2047d: that decodes strings that
+ are encoded as per RFC 2047.
- expands to "[a]:[b]:[c] (x)-(y)-(z)". At the end of the expansion, the
- value of $item is restored to what it was before.
+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.
- * ${filter{<string1>}{<condition>}}
+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.
- After expansion, <string1> is interpreted as a list, colon-separated by
- default, but the separator can be changed in the usual way. For each item
- in this list, its value is place in $item, and then the condition is
- evaluated. If the condition is true, $item is added to the output as an
- item in a new list; if the condition is false, the item is discarded. The
- separator used for the output list is the same as the one used for the
- input, but is not included in the output. For example:
+12. There are two new expansion conditions that iterate over a list. They are
+ called forany and forall.
- ${filter{a:b:c}{!eq{$item}{b}}
+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).
- yields "a:c". At the end of the expansion, the value of $item is restored
- to what it was before.
+14. The smtp transport has a new option called hosts_avoid_pipelining.
- * ${reduce{<string1>}{<string2>}{<string3>}}
+15. By default, exigrep does case-insensitive matches. There is now a -I option
+ that makes it case-sensitive.
- The ${reduce expansion operation reduces a list to a single, scalar string.
- After expansion, <string1> is interpreted as a list, colon-separated by
- default, but the separator can be changed in the usual way. Then <string2>
- is expanded and assigned to the $value variable. After this, each item in
- the <string1> list is assigned to $item in turn, and <string3> is expanded
- for each of them. The result of that expansion is assigned to $value before
- the next iteration. When the end of the list is reached, the final value of
- $value is added to the expansion string. The ${reduce expansion item can be
- used in a number of ways. For example, to add up a list of numbers:
+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.
- ${reduce {<, 1,2,3}{0}{${eval:$value+$item}}}
+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.
- The result of that expansion would be "6". The maximum of a list of numbers
- can be found:
+18. It is now possible to use newline and other control characters (those with
+ values less than 32, plus DEL) as separators in lists.
- ${reduce {3:0:9:4:6}{0}{${if >{$item}{$value}{$item}{$value}}}}
+19. The exigrep utility now has a -v option, which inverts the matching
+ condition.
- At the end of a ${reduce expansion, the values of $item and $value is
- restored to what they were before.
+20. The host_find_failed option in the manualroute router can now be set to
+ "ignore".
Version 4.66
git://git.exim.org / exim.git / blobdiff