-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.96 2006/03/09 15:10:16 ph10 Exp $
+$Cambridge: exim/doc/doc-txt/NewStuff,v 1.124 2006/12/05 11:35:28 ph10 Exp $
New Features in Exim
--------------------
-This file contains descriptions of new features that have been added to Exim,
-but have not yet made it into the main manual (which is most conveniently
-updated when there is a relatively large batch of changes). The doc/ChangeLog
-file contains a listing of all changes, including bug fixes.
+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
+the documentation is updated, this file is reduced to a short list.
+
+
+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.
+
+ 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, thus setting message-specific variables such
+ as $message_size and the header variables. The $recipients variable is
+ available. This feature is provided to make it easier to test expansions
+ that make use of these variables. However, Exim must be called by an admin
+ user when -Mset is used.
+
+ 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. For example:
+
+ exim -bem /tmp/testmessage
+
+ The file is read as a message (as if receiving a locally-submitted non-SMTP
+ message) before any of the test expansions are done. Thus, message-specific
+ variables such as $message_size and $h_from: are available. However, no
+ Received: header is added to the message. If the -t option is set,
+ recipients are read from the headers in the normal way, and are shown in
+ the $recipients variable. Note that recipients cannot be given on the
+ command line, because further arguments are taken as strings to expand
+ (just like -be).
+
+ 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. You can revert to
+ the previous behavious, that is, delay the recipient independent of the
+ sender, by setting address_retry_include_sender=false in the smtp
+ transport. However, this can lead to problems with servers that regularly
+ issue 4xx responses to RCPT commands.
+
+10. Unary negation and the bitwise logical operators and, or, xor, not, and
+ shift, have been added to the eval: and eval10: expansion items. These
+ items may now contain arithmetic operators (plus, minus, times, divide,
+ remainder, negate), bitwise operators (and, or, xor, not, shift), and
+ parentheses. All operations are carried out using signed integer
+ arithmetic. Operator priorities are as in C, namely:
+
+ (highest) not, negate
+ times, divide, remainder
+ plus, minus
+ shift-left, shift-right
+ and
+ xor
+ (lowest) or
+
+ Binary operators with the same priority are evaluated from left to right.
+ For example:
+
+ ${eval:1+1} yields 2
+ ${eval:1+2*3} yields 7
+ ${eval:(1+2)*3} yields 9
+ ${eval:2+42%5} yields 4
+ ${eval:0xc&5} yields 4
+ ${eval:0xc|5} yields 13
+ ${eval:0xc^5} yields 9
+ ${eval:0xc>>1} yields 6
+ ${eval:0xc<<1} yields 24
+ ${eval:~255&0x1234} yields 4608
+ ${eval:-(~255&0x1234)} yields -4608
+
+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 acl verbs to vary the message
+ that is sent when an SMTP command is accepted. For example, in a RCPT ACL
+ you could have:
+
+ accept <some conditions>
+ message = OK, I'll allow you through today
+
+ Previously, this message modifier would have had no effect whatsoever.
+
+ IMPORTANT: The new behaviour applies to "accept" (and "discard") only if
+ there is no occurrence of "endpass" in the statement. If "endpass" is
+ present, the behaviour reverts to the old case, where "message" applies to
+ rejection. This is for backwards compatibility.
+
+ It is always possible to rewrite ACL statements so that "endpass" is not
+ needed (and indeed it is no longer used in the default configuration, and
+ is somewhat not recommended nowadays because it causes confusion.)
+
+ It is now generally true that the "message" modifier sets up a text string
+ that is expanded and used as a response message if the current statement
+ terminates the ACL. The expansion happens at the time Exim decides that the
+ ACL is to end, not at the time it processes "message". If the expansion
+ fails, or generates an empty string, the modifier is ignored.
+
+ For ACLs that are triggered by SMTP commands, the message is returned as
+ part of the SMTP response. In this situation, the message may begin with an
+ overriding SMTP response code, optionally followed by an "extended response
+ code". However, the first digit of the supplied response code must be the
+ same as would be sent by default. A panic occurs if it is not. For the
+ predata ACL, note that the default success code is 354, not 2xx.
+
+ However, notwithstanding the previous paragraph, for the QUIT ACL, unlike
+ the others, the message modifier cannot override the 221 response code.
+
+ In the case of the "connect" ACL, accepting with a message modifier
+ overrides the value of smtp_banner.
+
+ The ACL test specified by acl_smtp_helo happens when the client issues the
+ HELO or EHLO commands, after the tests specified by helo_accept_junk_hosts,
+ helo_allow_chars and helo(_try)_verify_hosts. An acceptance message
+ modifier for EHLO/HELO may not contain more than one line (it will be
+ truncated at the first newline and a panic logged), and it cannot affect
+ the EHLO options.
+
+
+
+Version 4.63
+------------
+
+1. There is a new Boolean option called filter_prepend_home for the redirect
+ router.
+
+2. There is a new acl, set by acl_not_smtp_start, which is run right at the
+ start of receiving a non-SMTP message, before any of the message has been
+ read.
+
+3. When an SMTP error message is specified in a "message" modifier in an ACL,
+ or in a :fail: or :defer: message in a redirect router, Exim now checks the
+ start of the message for an SMTP error code.
+
+4. There is a new parameter for LDAP lookups called "referrals", which takes
+ one of the settings "follow" (the default) or "nofollow".
+
+5. Version 20070721.2 of exipick now included, offering these new options:
+ --reverse
+ After all other sorting options have bee processed, reverse order
+ before displaying messages (-R is synonym).
+ --random
+ Randomize order of matching messages before displaying.
+ --size
+ Instead of displaying the matching messages, display the sum
+ of their sizes.
+ --sort <variable>[,<variable>...]
+ Before displaying matching messages, sort the messages according to
+ each messages value for each variable.
+ --not
+ Negate the value for every test (returns inverse output from the
+ same criteria without --not).
+
+
+Version 4.62
+------------
+
+1. The ${readsocket expansion item now supports Internet domain sockets as well
+ as Unix domain sockets. If the first argument begins "inet:", it must be of
+ the form "inet:host:port". The port is mandatory; it may be a number or the
+ name of a TCP port in /etc/services. The host may be a name, or it may be an
+ IP address. An ip address may optionally be enclosed in square brackets.
+ This is best for IPv6 addresses. For example:
+
+ ${readsocket{inet:[::1]:1234}{<request data>}...
+
+ Only a single host name may be given, but if looking it up yield more than
+ one IP address, they are each tried in turn until a connection is made. Once
+ a connection has been made, the behaviour is as for ${readsocket with a Unix
+ domain socket.
+
+2. If a redirect router sets up file or pipe deliveries for more than one
+ incoming address, and the relevant transport has batch_max set greater than
+ one, a batch delivery now occurs.
+
+3. The appendfile transport has a new option called maildirfolder_create_regex.
+ Its value is a regular expression. For a maildir delivery, this is matched
+ against the maildir directory; if it matches, Exim ensures that a
+ maildirfolder file is created alongside the new, cur, and tmp directories.
+
Version 4.61
------------
-PH/01 There is a new global option called disable_ipv6, which does exactly what
- its name implies. If set true, even if the Exim binary has IPv6 support,
- no IPv6 activities take place. AAAA records are never looked up for host
- names given in manual routing data or elsewhere. AAAA records that are
- received from the DNS as additional data for MX records are ignored. Any
- IPv6 addresses that are listed in local_interfaces, manualroute route
- data, etc. are also ignored. If IP literals are enabled, the ipliteral
- router declines to handle IPv6 literal addresses.
-
-PH/02 There are now 20 of each type of ACL variable by default (instead of 10).
- It is also possible to change the numbers by setting ACL_CVARS and/or
- ACL_MVARS in Local/Makefile. Backward compatibility is maintained if you
- upgrade to this release with existing messages containing ACL variable
- settings on the queue. However, going in the other direction
- (downgrading) will not be compatible; the values of ACL variables will be
- lost.
-
-PH/03 If quota_warn_message contains a From: header, Exim now refrains from
- adding the default one. Similarly, if it contains a Reply-To: header, the
- errors_reply_to option, if set, is not used.
-
-PH/04 The variables $auth1, $auth2, $auth3 are now available in authenticators,
- containing the same values as $1, $2, $3. The new variables are provided
- because the numerical variables can be reset during string expansions
- (for example, during a "match" operation) and so may lose the
- authentication data. The preferred variables are now the new ones, with
- the use of the numerical ones being deprecated, though the support will
- not be removed, at least, not for a long time.
-
-PH/05 The "control=freeze" ACL modifier can now be followed by /no_tell. If
- the global option freeze_tell is set, it is ignored for the current
- message (that is, nobody is told about the freezing), provided all the
- "control=freeze" modifiers that are obeyed in the current message have
- the /no_tell option.
-
-PH/06 In both GnuTLS and OpenSSL, an expansion of tls_privatekey that results
- in an empty string is now treated as unset.
-
-PH/07 There is a new log selector called sender_verify_fail, which is set by
- default. If it is unset, the separate log line that gives details of a
- sender verification failure is not written. Log lines for the rejection
- of SMTP commands (e.g. RCPT) contain just "sender verify failed", so some
- detail is lost.
-
-PH/08 The default for dns_check_names_pattern now allows slashes within names,
- as there are now some PTR records that contain slashes. This check is
- only to protect against broken name servers that fall over on strange
- characters, so the fact that it applies to all lookups doesn't matter.
-
-PH/09 The default for rfc4131_query_timeout has been changed from 30s to 5s.
-
-PH/10 When compiled on FreeBSD, NetBSD, or BSD/OS, the pipe transport has a new
- Boolean option called use_classresources, defaulting false. If it is set
- true, the setclassresources() function is used to set resource limits
- when a pipe transport is run to perform a delivery. The limits for the
- uid under which the pipe is to run are obtained from the login class
- database.
-
-PH/11 If retry_interval_max is set greater than 24 hours, it is quietly reset
- to 24 hours. This avoids potential overflow problems when processing G
- and H retry rules, and it seems reasonable to require a retry at least
- once a day.
-
-PH/12 When the plaintext authenticator is running as a client, the server
- challenges are now checked to ensure they are valid base64 strings. The
- default action on failure is to abort the authentication. However, if
- client_ignore_invalid_base64 is set true, invalid responses are ignored.
-
-PH/13 When the plaintext authenticator is running as a client, the challenges
- from the server are placed in $auth1, $auth2, etc. as they are received.
- Thus, the challege that is received in response to sending the first
- string (with the AUTH command) can be used in the expansion of the second
- string, and so on. Currently, up to 3 challenge strings are available in
- this way. If an invalid base64 string is received when client_ignore_
- invalid_base64 is set, an empty string is put in the $auth<n> variable.
-
-PH/14 Messages created by the autoreply transport now contain a References:
- header. This is constructed in accordance with rules that are described
- in section 3.64 of RFC 2822, which states that replies should contain
- such a header line, and section 3.14 of RFC 3834, which states that
- automatic responses are not different in this respect. However, because
- some mail processing software does not cope well with very long header
- lines, no more than 12 message IDs are copied from the References: header
- line in the incoming message. If there are more than 12, the first one
- and then the final 11 are copied, before adding the message ID of the
- incoming message.
-
-PH/15 The smtp transport has a new option called authenticated_sender_force.
- When set true, it allows the authenticated_sender option's value to be
- used, even if Exim has not authenticated as a client.
-
-PH/16 The expansion ${time_eval:<string>} converts an Exim time string such as
- 2d4h1m into a number of seconds.
-
-PH/17 The ACL modifier control=allow_auth_unadvertised can be used to permit a
- client host to use the SMTP AUTH command even when it has not been
- advertised in response to EHLO. Furthermore, because there are apparently
- some really broken clients that do this, Exim will even accept AUTH after
- HELO when this control is set. It should only be used if you really need
- it, and you should limit its use to those broken hosts that do not work
- without it. For example:
-
- warn hosts = 192.168.34.25
- control = allow_auth_unadvertised
-
- This control is permitted only in the connection and HELO ACLs.
-
-PH/18 There is a new ACL modifier called "add_header" which does what its name
- implies. It specifies one of more header lines that are to be added to an
- incoming message, assuming, of course, that the message is ultimately
- accepted.
-
- This modifier is permitted in the MAIL, RCPT, PREDATA, DATA, MIME, and
- non-SMTP ACLs (in other words, those that are concerned with accepting a
- message). Added header lines are accumulated during the MAIL, RCPT, and
- PREDATA ACLs, with any duplicates being discarded. They are then added to
- the message before processing the DATA and MIME ACLs, during which
- further added header lines are accumulated, again with duplicates
- discarded. Thus, it is possible to add two identical header lines to an
- SMTP message, but only if one is added before DATA and one after.
-
- In the case of non-SMTP messages, new headers are accumulated during the
- non-SMTP ACL, and added to the message at the end.
-
- The add_header modifier is available for use with all ACL verbs. In the
- case of the WARN verb, add_header supersedes the use of "message" for
- this purpose; for the other verbs, it provides a new facility. If both
- add_header and "message" are present on a WARN verb, both are processed
- according to their specifications.
-
- The add_header modifier acts immediately it is encountered during the
- processing of an ACL. This is different to the (now-deprecated) use of
- "message" on a WARN verb, where the action is taken only if all the
- conditions are true. Notice the difference between these two cases on a
- RCPT ACL:
-
- deny add_header = ADDED: some text
- <some condition>
-
- deny <some condition>
- add_header = ADDED: some text
-
- In the first case, the header is always added, whether or not the current
- recipient is rejected. In the second case, the header is added only if
- the recipient is rejected.
-
- If add_header appears more than once on an ACL statement, multiple
- headers are added, provided that they have different content. (In the
- case of WARN with "message", only the last value of "message" is used.)
-
- The facility for specifying where the new header is to be inserted, as
- described for WARN with "message" in section 39.19 of the 4.60 manual, is
- supported.
-
-PH/19 The following errors can now be detected in retry rules:
-
- mail_4xx This is like rcpt_4xx, but applies to MAIL commands
-
- data_4xx This is like rcpt_4xx, but applies to DATA commands and the
- response code after the end of the data
-
- lost_connection This error occurs when the server unexpectedly closes
- the SMTP connection. There may, of course, legitmate reasons
- for this (host died, network died), but if it repeats a lot
- for the same host, it indicates something odd.
-
- tls_required The server was required to use TLS (hosts_require_tls),
- but either did not offer it, or responded with 4xx to
- STARTTLS, or there was a problem setting up the TLS connection
-
- Note that a 5xx response to STARTTLS is a permanent error.
+The documentation is up-to-date for the 4.61 release. Major new features since
+the 4.60 release are:
+
+. An option called disable_ipv6, to disable the use of IPv6 completely.
+
+. An increase in the number of ACL variables to 20 of each type.
+
+. A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
+ $2, $3, (though those are still set) because the numeric variables get used
+ for other things in complicated expansions.
+
+. The default for rfc1413_query_timeout has been changed from 30s to 5s.
+
+. It is possible to use setclassresources() on some BSD OS to control the
+ resources used in pipe deliveries.
+
+. A new ACL modifier called add_header, which can be used with any verb.
+
+. More errors are detectable in retry rules.
+There are a number of other additions too.
Version 4.60
git://git.exim.org / users / heiko / exim.git / blobdiff