-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.11 2004/11/17 16:12:26 ph10 Exp $
+$Cambridge: exim/doc/doc-txt/NewStuff,v 1.141 2007/02/14 14:59:01 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 4.44
+Version 4.67
------------
- 1. There is a new build-time option called CONFIGURE_GROUP which works like
- CONFIGURE_OWNER. It specifies one additional group that is permitted for
- the runtime configuration file when the group write permission is set.
+ 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.
- 2. The "control=submission" facility has a new option /retain_sender. This
- has the effect of setting local_sender_retain true and local_from_check
- false for the incoming message in which it is encountered.
+ 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.
- 3. $recipients is now available in the predata ACL (oversight).
+ 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,
- 4. The value of address_data from a sender verification is now available in
- $sender_address_data in subsequent conditions in the ACL statement. Note:
- this is just like $address_data. The value does not persist after the end
- of the current ACL statement. If you want to preserve it, you can use one
- of the ACL variables.
+ C=EHLO,QUIT
- 5. The redirect router has two new options: forbid_sieve_filter and
- forbid_exim_filter. When filtering is enabled by allow_filter, these
- options control which type(s) of filtering are permitted. By default, both
- Exim and Sieve filters are allowed.
+ 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.
- 6. A new option for callouts makes it possible to set a different (usually
- smaller) timeout for making the SMTP connection. The keyword is "connect".
- For example:
+ 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
- verify = sender/callout=5s,connect=1s
+ dnslists = a.b.c=127.0.0.1
- If not specified, it defaults to the general timeout value.
+ 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?
- 7. The new variables $sender_verify_failure and $recipient_verify_failure
- contain information about exactly what failed. In an ACL, after one of
- these failures, the relevant variable contains one of the following words:
+ 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.
- qualify the address was unqualified (no domain), and the message
- was neither local nor came from an exempted host;
+ 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:
- route routing failed;
+ . If = or & is used, the condition is true if any one of the looked up
+ IP addresses matches one of the listed addresses. Consider:
- mail routing succeeded, and a callout was attempted; rejection
- occurred at or before the MAIL command (that is, on initial
- connection, HELO, or MAIL);
+ dnslists = a.b.c=127.0.0.1
- recipient the RCPT command in a callout was rejected;
+ 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.
- postmaster the postmaster check in a callout was rejected.
+ . 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:
- The main use of these variables is expected to be to distinguish between
- rejections of MAIL and rejections of RCPT.
+ dnslists = a.b.c==127.0.0.1
- 8. The command line option -dd behaves exactly like -d except when used on a
- command that starts a daemon process. In that case, debugging is turned off
- for the subprocesses that the daemon creates. Thus, it is useful for
- monitoring the behaviour of the daemon without creating as much output as
- full debugging.
+ 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
- 9. $host_address is now set to the target address during the checking of
- ignore_target_hosts.
+ dnslists = a.b.c==127.0.0.1,127.0.0.2
-10. There are four new variables called $spool_space, $log_space,
- $spool_inodes, and $log_inodes. The first two contain the amount of free
- space in the disk partitions where Exim has its spool directory and log
- directory, respectively. (When these are in the same partition, the values
- will, of course, be the same.) The second two variables contain the numbers
- of free inodes in the respective partitions.
+ for the condition to be true.
- NOTE: Because disks can nowadays be very large, the values in the space
- variables are in kilobytes rather than in bytes. Thus, for example, to
- check in an ACL that there is at least 50M free on the spool, you would
- write:
+ When ! is used to negate IP address matching, it inverts the result, giving
+ the precise opposite of the behaviour above. Thus:
- condition = ${if > {$spool_space}{50000}{yes}{no}}
+ . If != or !& is used, the condition is true if none of the looked up IP
+ addresses matches one of the listed addresses. Consider:
- The values are recalculated whenever any of these variables is referenced.
- If the relevant file system does not have the concept of inodes, the value
- of those variables is -1. If the operating system does not have the ability
- to find the amount of free space (only true for experimental systems), the
- space value is -1.
+ dnslists = a.b.c!&0.0.0.1
-11. It is now permitted to omit both strings after an "if" condition; if the
- condition is true, the result is the string "true". As before, when the
- second string is omitted, a false condition yields an empty string. This
- makes it less cumbersome to write custom ACL and router conditions. For
- example, instead of
+ 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.
- condition = ${if eq {$acl_m4}{1}{yes}{no}}
+ . If !== or !=& is used, the condition is true there is at least one looked
+ up IP address that does not match. Consider:
- or the shorter form
+ dnslists = a.b.c!=&0.0.0.1
- condition = ${if eq {$acl_m4}{1}{yes}}
+ 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
- (because the second string has always defaulted to ""), you can now write
+ dnslists = a.b.c!=&0.0.0.1,0.0.0.2
- condition = ${if eq {$acl_m4}{1}}
+ for the condition to be false.
- Previously this was a syntax error.
+ When the DNS lookup yields only a single IP address, there is no difference
+ between = and == and between & and =&.
+
+ 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.
-Version 4.43
-------------
+ 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. 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. 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:
+
+ helo_data = ${lookup dnsdb{ptr=$sending_ip_address}{$value}\
+ {$primary_hostname}}
+
+ The use of helo_data applies both to sending messages and when doing
+ callouts.
+
+ 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.
+
+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. The effect of the
+ new default behaviour is to disable the PIPELINING optimization in these
+ situations, in order to avoid unexpected timeouts in clients.
+
+12. There are two new expansion conditions that iterate over a list. They are
+ called forany and forall, and they are used like this:
+
+ ${if forany{<a list>}{<a condition>}{<yes-string>}{<no-string>}}
+ ${if forall{<a list>}{<a condition>}{<yes-string>}{<no-string>}}
+
+ 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.
+
+ - 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.
+
+ - 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.
+
+ 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 this example, the list separator is changed to a comma:
+
+ ${if forany{<, $recipients}{match{$item}{^user3@}}{yes}{no}}
+
+ Outside a forany/forall condition, the value of $item is an empty string.
+ Its value is saved and restored while forany/forall is being processed, to
+ enable these expansion items to be nested.
+
+13. There's a new global option called dsn_from that can be used to vary the
+ contents of From: lines in bounces and other automatically generated
+ messages ("delivery status notifications" - hence the name of the option).
+ The default setting is:
+
+ dsn_from = Mail Delivery System <Mailer-Daemon@$qualify_domain>
+
+ The value is expanded every time it is needed. If the expansion fails, a
+ panic is logged, and the default setting is used.
+
+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).
+
+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 Boolean global option called mua_wrapper, defaulting false.
- This causes Exim to run an a restricted mode, in order to provide a very
- specific service.
-
- Background: On a personal computer, it is a common requirement for all
- email to be sent to a smarthost. There are plenty of MUAs that can be
- configured to operate that way, for all the popular operating systems.
- However, there are MUAs for Unix-like systems that cannot be so configured:
- they submit messages using the command line interface of
- /usr/sbin/sendmail. In addition, utility programs such as cron submit
- messages this way.
-
- Requirement: The requirement is for something that can provide the
- /usr/sbin/sendmail interface and deliver messages to a smarthost, but not
- provide any queueing or retrying facilities. Furthermore, the delivery to
- the smarthost should be synchronous, so that if it fails, the sending MUA
- is immediately informed. In other words, we want something that in effect
- converts a command-line MUA into a TCP/SMTP MUA.
-
- Solutions: There are a number of applications (for example, ssmtp) that do
- this job. However, people have found them to be lacking in various ways.
- For instance, some sites want to allow aliasing and forwarding before
- sending to the smarthost.
-
- Using Exim: Exim already had the necessary infrastructure for doing this
- job. Just a few tweaks were needed to make it behave as required, though it
- is somewhat of an overkill to use a fully-featured MTA for this purpose.
-
- Setting mua_wrapper=true causes Exim to run in a special mode where it
- assumes that it is being used to "wrap" a command-line MUA in the manner
- just described.
-
- If you set mua_wrapper=true, you also need to provide a compatible router
- and transport configuration. Typically there will be just one router and
- one transport, sending everything to a smarthost.
-
- When run in MUA wrapping mode, the behaviour of Exim changes in the
- following ways:
-
- (a) A daemon cannot be run, nor will Exim accept incoming messages from
- inetd. In other words, the only way to submit messages is via the
- command line.
-
- (b) Each message is synchonously delivered as soon as it is received (-odi
- is assumed). All queueing options (queue_only, queue_smtp_domains,
- control=queue, control=freeze in an ACL etc.) are quietly ignored. The
- Exim reception process does not finish until the delivery attempt is
- complete. If the delivery was successful, a zero return code is given.
-
- (c) Address redirection is permitted, but the final routing for all
- addresses must be to the same remote transport, and to the same list of
- hosts. Furthermore, the return_address must be the same for all
- recipients, as must any added or deleted header lines. In other words,
- it must be possible to deliver the message in a single SMTP
- transaction, however many recipients there are.
-
- (d) If the conditions in (c) are not met, or if routing any address results
- in a failure or defer status, or if Exim is unable to deliver all the
- recipients successfully to one of the hosts immediately, delivery of
- the entire message fails.
-
- (e) Because no queueing is allowed, all failures are treated as permanent;
- there is no distinction between 4xx and 5xx SMTP response codes from
- the smarthost. Furthermore, because only a single yes/no response can
- be given to the caller, it is not possible to deliver to some
- recipients and not others. If there is an error (temporary or
- permanent) for any recipient, all are failed.
-
- (f) If more than one host is listed, Exim will try another host after a
- connection failure or a timeout, in the normal way. However, if this
- kind of failure happens for all the hosts, the delivery fails.
-
- (g) When delivery fails, an error message is written to the standard error
- stream (as well as to Exim's log), and Exim exits to the caller with a
- return code value 1. The message is expunged from Exim's spool files.
- No bounce messages are ever generated.
-
- (h) No retry data is maintained, and any retry rules are ignored.
-
- (i) A number of Exim options are overridden: deliver_drop_privilege is
- forced true, max_rcpt in the smtp transport is forced to "unlimited",
- remote_max_parallel is forced to one, and fallback hosts are ignored.
-
- The overall effect is that Exim makes a single synchronous attempt to
- deliver the message, failing if there is any kind of problem. Because no
- local deliveries are done and no daemon can be run, Exim does not need root
- privilege. It should be possible to run it setuid=exim instead of
- setuid=root. See section 48.3 in the 4.40 manual for a general discussion
- about the advantages and disadvantages of running without root privilege.
-
- 2. There have been problems with DNS servers when SRV records are looked up.
- Some mis-behaving servers return a DNS error or timeout when a non-existent
- SRV record is sought. Similar problems have in the past been reported for
- MX records. The global dns_again_means_nonexist option can help with this
- problem, but it is heavy-handed because it is a global option. There are
- now two new options for the dnslookup router. They are called
- srv_fail_domains and mx_fail_domains. In each case, the value is a domain
- list. If an attempt to look up an SRV or MX record results in a DNS failure
- or "try again" response, and the domain matches the relevant list, Exim
- behaves as if the DNS had responded "no such record". In the case of an SRV
- lookup, this means that the router proceeds to look for MX records; in the
- case of an MX lookup, it proceeds to look for A or AAAA records, unless the
- domain matches mx_domains.
-
- 3. The following functions are now available in the local_scan() API:
-
- (a) void header_remove(int occurrence, uschar *name)
-
- This function removes header lines. If "occurrence" is zero or negative,
- all occurrences of the header are removed. If occurrence is greater
- than zero, that particular instance of the header is removed. If no
- header(s) can be found that match the specification, the function does
- nothing.
-
- (b) BOOL header_testname(header_line *hdr, uschar *name, int length,
- BOOL notdel)
-
- This function tests whether the given header has the given name. It
- is not just a string comparison, because whitespace is permitted
- between the name and the colon. If the "notdel" argument is TRUE, a
- FALSE return is forced for all "deleted" headers; otherwise they are
- not treated specially. For example:
-
- if (header_testname(h, US"X-Spam", 6, TRUE)) ...
-
- (c) void header_add_at_position(BOOL after, uschar *name, BOOL topnot,
- int type, char *format, ...)
-
- This function adds a new header line at a specified point in the header
- chain. If "name" is NULL, the new header is added at the end of the
- chain if "after" is TRUE, or at the start if "after" is FALSE. If
- "name" is not NULL, the headers are searched for the first non-deleted
- header that matches the name. If one is found, the new header is added
- before it if "after" is FALSE. If "after" is true, the new header is
- added after the found header and any adjacent subsequent ones with the
- same name (even if marked "deleted"). If no matching non-deleted header
- is found, the "topnot" option controls where the header is added. If it
- is TRUE, addition is at the top; otherwise at the bottom. Thus, to add
- a header after all the Received: headers, or at the top if there are no
- Received: headers, you could use
-
- header_add_at_position(TRUE, US"Received", TRUE, ' ', "X-xxx: ...");
-
- Normally, there is always at least one non-deleted Received: header,
- but there may not be if received_header_text expands to an empty
- string.
-
- (d) BOOL receive_remove_recipient(uschar *recipient)
-
- This is a convenience function to remove a named recipient from the
- list of recipients. It returns TRUE if a recipient was removed, and
- FALSE if no matching recipient could be found. The argument must be a
- complete email address.
-
- 4. When an ACL "warn" statement adds one or more header lines to a message,
- they are added at the end of the existing header lines by default. It is
- now possible to specify that any particular header line should be added
- right at the start (before all the Received: lines) or immediately after
- the first block of Received: lines in the message. This is done by
- specifying :at_start: or :after_received: (or, for completeness, :at_end:)
- before the text of the header line. (Header text cannot start with a colon,
- as there has to be a header name first.) For example:
-
- warn message = :after_received:X-My-Header: something or other...
-
- If more than one header is supplied in a single warn statement, each one is
- treated independently and can therefore be placed differently. If you add
- more than one line at the start, or after the Received: block, they will
- end up in reverse order.
-
- Warning: This facility currently applies only to header lines that are
- added in an ACL. It does NOT work for header lines that are added in a
- system filter or in a router or transport.
-
- 5. There is now a new error code that can be used in retry rules. Its name is
- "rcpt_4xx", and there are three forms. A literal "rcpt_4xx" matches any 4xx
- error received for an outgoing SMTP RCPT command; alternatively, either the
- first or both of the x's can be given as digits, for example: "rcpt_45x" or
- "rcpt_436". If you want (say) to recognize 452 errors given to RCPT
- commands by a particular host, and have only a one-hour retry for them, you
- can set up a retry rule of this form:
-
- the.host.name rcpt_452 F,1h,10m
-
- Naturally, this rule must come before any others that would match.
-
- These new errors apply to both outgoing SMTP (the smtp transport) and
- outgoing LMTP (either the lmtp transport, or the smtp transport in LMTP
- mode). Note, however, that they apply only to responses to RCPT commands.
-
- 6. The "postmaster" option of the callout feature of address verification has
- been extended to make it possible to use a non-empty MAIL FROM address when
- checking a postmaster address. The new suboption is called "postmaster_
- mailfrom", and you use it like this:
-
- require verify = sender/callout=postmaster_mailfrom=abc@x.y.z
-
- Providing this suboption causes the postmaster check to be done using the
- given address. The original "postmaster" option is equivalent to
-
- require verify = sender/callout=postmaster_mailfrom=
-
- If both suboptions are present, the rightmost one overrides.
-
- Important notes:
-
- (1) If you use a non-empty sender address for postmaster checking, there is
- the likelihood that the remote host will itself initiate a callout
- check back to your host to check that address. As this is a "normal"
- callout check, the sender will most probably be empty, thus avoiding
- possible callout loops. However, to be on the safe side it would be
- best to set up your own ACLs so that they do not do sender verification
- checks when the recipient is the address you use for postmaster callout
- checking.
-
- (2) The caching arrangements for postmaster checking do NOT take account of
- the sender address. It is assumed that either the empty address, or a
- fixed non-empty address will be used. All that Exim remembers is that
- the postmaster check for the domain succeeded or failed.
-
- 7. When verifying addresses in header lines using the verify=header_sender
- option, Exim behaves by default as if the addresses are envelope sender
- addresses from a message. Callout verification therefore tests to see
- whether a bounce message could be delivered, by using an empty address in
- the MAIL FROM command. However, it is arguable that these addresses might
- never be used as envelope senders, and could therefore justifiably reject
- bounce messages (empty senders). There is now an additional callout option
- for verify=header_sender that allows you to specify what address to use in
- the MAIL FROM command. You use it as in this example:
-
- require verify = header_sender/callout=mailfrom=abcd@x.y.z
-
- Important notes:
-
- (1) As in the case of postmaster_mailfrom (see above), you should think
- about possible loops.
-
- (2) In this case, as in the case of recipient callouts with non-empty
- senders (the use_sender option), caching is done on the basis of a
- recipient/sender pair.
+ * ${addresses:<string>}
- 8. If you build Exim with USE_READLINE=yes in Local/Makefile, it will try to
- load libreadline dynamically whenever the -be (test expansion) option is
- used without command line arguments. If successful, it will then use
- readline() for reading the test data. A line history is supported. By the
- time Exim does this, it is running as the calling user, so this should not
- cause any security problems. Security is the reason why this is NOT
- supported for -bt or -bv, when Exim is running as root or exim,
- respectively. Note that this option adds to the size of the Exim binary,
- because the dynamic loading library is not otherwise included. On my
- desktop it adds about 2.5K. You may need to add -ldl to EXTRA_LIBS when you
- set USE_READLINE=yes.
-
- 9. Added ${str2b64:<string>} to the expansion operators. This operator
- converts an arbitrary string into one that is base64 encoded.
-
-10. A new authenticator, called cyrus_sasl, has been added. This requires
- the presence of the Cyrus SASL library; it authenticates by calling this
- library, which supports a number of authentication mechanisms, including
- PLAIN and LOGIN, but also several others that Exim does not support
- directly. The code for this authenticator was provided by Matthew
- Byng-Maddick of A L Digital Ltd (http://www.aldigital.co.uk). Here follows
- draft documentation:
+ 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.
- xx. THE CYRUS_SASL AUTHENTICATOR
-
- The cyrus_sasl authenticator provides server support for the Cyrus library
- Implementation of the RFC 2222 "Simple Authentication and Security Layer".
- It provides a gatewaying mechanism directly to the Cyrus interface, so if
- your Cyrus library can do, for example, CRAM-MD5, then so can the
- cyrus_sasl authenticator. By default it uses the public name of the driver
- to determine which mechanism to support.
+ 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:
- Where access to some kind of secret file is required, for example in GSSAPI
- or CRAM-MD5, it is worth noting that the authenticator runs as the exim
- user, and that the Cyrus SASL library has no way of escalating privileges
- by default. You may also find you need to set environment variables,
- depending on the driver you are using.
+ ${addresses:>& The Boss <ceo@up.stairs>, sec@base.ment (dogsbody)}
- xx.1 Using cyrus_sasl as a server
+ expands to "ceo@up.stairs&sec@base.ment". Compare ${address (singular),
+ which extracts the working address from a single RFC2822 address.
- The cyrus_sasl authenticator has four private options. It puts the username
- (on a successful authentication) into $1.
+ * ${map{<string1>}{<string2>}}
- server_hostname Type: string* Default: $primary_hostname
+ 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:
- This option selects the hostname that is used when communicating with
- the library. It is up to the underlying SASL plug-in what it does with
- this data.
+ ${map{a:b:c}{[$item]}} ${map{<- x-y-z}{($item)}}
- server_mech Type: string Default: public_name
+ 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.
- This option selects the authentication mechanism this driver should
- use. It allows you to use a different underlying mechanism from the
- advertised name. For example:
+ * ${filter{<string1>}{<condition>}}
- sasl:
- driver = cyrus_sasl
- public_name = X-ANYTHING
- server_mech = CRAM-MD5
- server_set_id = $1
-
- server_realm Type: string Default: unset
-
- This is the SASL realm that the server is claiming to be in.
-
- server_service Type: string Default: "smtp"
-
- This is the SASL service that the server claims to implement.
-
- For straigthforward cases, you do not need to set any of the
- authenticator's private options. All you need to do is to specify an
- appropriate mechanism as the public name. Thus, if you have a SASL library
- that supports CRAM-MD5 and PLAIN, you might have two authenticators as
- follows:
+ 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:
+
+ ${filter{a:b:c}{!eq{$item}{b}}
+
+ yields "a:c". At the end of the expansion, the value of $item is restored
+ to what it was before.
+
+ * ${reduce{<string1>}{<string2>}{<string3>}}
+
+ 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:
+
+ ${reduce {<, 1,2,3}{0}{${eval:$value+$item}}}
- sasl_cram_md5:
- driver = cyrus_sasl
- public_name = CRAM-MD5
- server_set_id = $1
-
- sasl_plain:
- driver = cyrus_sasl
- public_name = PLAIN
- server_set_id = $1
-
-11. There is a new global option called tls_on_connect_ports. Its value must be
- a list of port numbers; the most common use is expected to be
-
- tls_on_connect_ports = 465
-
- Setting this option has the same effect as -tls-on-connect on the command
- line, but only for the specified ports. It applies to all connections, both
- via the daemon and via inetd. You still need to specify all the ports for
- the daemon (using daemon_smtp_ports or local_interfaces or the -X command
- line option) because this option does not add an extra port -- rather, it
- specifies different behaviour on a port that is defined elsewhere. The
- -tls-on-connect command line option overrides tls_on_connect_ports, and
- forces tls-on-connect for all ports.
-
-12. There is a new ACL that is run when a DATA command is received, before the
- data itself is received. The ACL is defined by acl_smtp_predata. (Compare
- acl_smtp_data, which is run after the data has been received.)
- This new ACL allows a negative response to be given to the DATA command
- itself. Header lines added by MAIL or RCPT ACLs are not visible at this
- time, but any that are defined here are visible when the acl_smtp_data ACL
- is run.
-
-13. The "control=submission" ACL modifier has an option "/domain=xxx" which
- specifies the domain to be used when creating From: or Sender: lines using
- the authenticated id as a local part. If the option is supplied with an
- empty domain, that is, just "/domain=", Exim assumes that the authenticated
- id is a complete email address, and it uses it as is when creating From:
- or Sender: lines.
-
-14. It is now possible to make retry rules that apply only when the failing
- message has a specific sender. In particular, this can be used to define
- retry rules that apply only to bounce messages. The syntax is to add a new
- third item to a retry rule, of the form "senders=<address list>". The retry
- timings themselves then become the fourth item. For example:
-
- * * senders=: F,1h,30m
-
- would match all bounce messages. If the address list contains white space,
- it must be enclosed in quotes. For example:
-
- a.domain timeout senders="x@b.dom : y@c.dom" G,8h,10m,1.5
-
- When testing retry rules using -brt, you can supply a sender using the -f
- command line option, like this:
-
- exim -f "" -brt user@dom.ain
-
- If you do not set -f with -brt, a retry rule that contains a senders list
- will never be matched.
-
-15. Two new control modifiers have been added to ACLs: "control = enforce_sync"
- and "control = no_enforce_sync". This makes it possible to be selective
- about when SMTP synchronization is enforced. The global option
- smtp_enforce_sync now specifies the default state of the switch. These
- controls can appear in any ACL, but the most obvious place to put them is
- in the ACL defined by acl_smtp_connect, which is run at the start of an
- incoming SMTP connection, before the first synchronization check.
-
-16. Another two new control modifiers are "control = caseful_local_part" and
- "control = caselower_local_part". These are permitted only in the ACL
- specified by acl_smtp_rcpt (i.e. during RCPT processing). By default, the
- contents of $local_part are lower cased before ACL processing.
- After "control = caseful_local_part", any uppercase letters in the original
- local part are restored in $local_part for the rest of the ACL, or until
- "control = caselower_local_part" is encountered. However, this applies only
- to local part handling that takes place directly in the ACL (for example,
- as a key in lookups). If a "verify = recipient" test is obeyed, the
- case-related handling of the local part during the verification is
- controlled by the router configuration (see the caseful_local_part generic
- router option).
-
- This facility could be used, for example, to add a spam score to local
- parts containing upper case letters. For example, using $acl_m4 to
- accumulate the spam score:
-
- warn control = caseful_local_part
- set acl_m4 = ${eval:\
- $acl_m4 + \
- ${if match{$local_part}{[A-Z]}{1}{0}}\
- }
- control = caselower_local_part
-
- Notice that we put back the lower cased version afterwards, assuming that
- is what is wanted for subsequent tests.
-
-17. The option hosts_connection_nolog is provided so that certain hosts can be
- excepted from logging when the +smtp_connection log selector is set. For
- example, you might want not to log SMTP connections from local processes,
- or from 127.0.0.1, or from your local LAN. The option is a host list with
- an unset default. Because it is consulted in the main loop of the daemon,
- you should strive to restrict its value to a short inline list of IP
- addresses and networks. To disable logging SMTP connections from local
- processes, you must create a host list with an empty item. For example:
-
- hosts_connection_nolog = :
-
- If the +smtp_connection log selector is not set, this option has no effect.
-
-18. There is now an acl called acl_smtp_quit, which is run for the QUIT
- command. The outcome of the ACL does not affect the response code to QUIT,
- which is always 221. Thus, the ACL does not in fact control any access.
- For this reason, the only verbs that are permitted are "accept" and "warn".
-
- The ACL can be used for tasks such as custom logging at the end of an SMTP
- session. For example, you can use ACL variables in other ACLs to count
- messages, recipients, etc., and log the totals at QUIT time using one or
- more "logwrite" modifiers on a "warn" command.
-
- You do not need to have a final "accept", but if you do, you can use a
- "message" modifier to specify custom text that is sent as part of the 221
- response.
-
- This ACL is run only for a "normal" QUIT. For certain kinds of disastrous
- failure (for example, failure to open a log file, or when Exim is bombing
- out because it has detected an unrecoverable error), all SMTP commands
- from the client are given temporary error responses until QUIT is received
- or the connection is closed. In these special cases, the ACL is not run.
-
-19. The appendfile transport has two new options, mailbox_size and mailbox_
- filecount. If either these options are set, it is expanded, and the result
- is taken as the current size of the mailbox or the number of files in the
- mailbox, respectively. This makes it possible to use some external means of
- maintaining the data about the size of a mailbox for enforcing quota
- limits. The result of expanding these option values must be a decimal
- number, optionally followed by "K" or "M".
-
-20. It seems that there are broken clients in use that cannot handle multiline
- SMTP responses. Can't people who implement these braindead programs read?
- RFC 821 mentions multiline responses, and it is over 20 years old. They
- must handle multiline responses for EHLO, or do they still use HELO?
- Anyway, here is YAWFAB (yet another workaround for asinine brokenness).
- There's a new ACL switch that can be set by
-
- control = no_multiline_responses
-
- If this is set, it suppresses multiline SMTP responses from ACL rejections.
- One way of doing this would have been just to put out these responses as
- one long line. However, RFC 2821 specifies a maximum of 512 bytes per
- response ("use multiline responses for more" it says), and some of the
- responses might get close to that. So I have implemented this by doing two
- very easy things:
-
- (1) Extra information that is normally output as part of a rejection
- caused by sender verification failure is omitted. Only the final line
- (typically "sender verification failed") is now sent.
-
- (2) If a "message" modifier supplies a multiline response, only the first
- line is output.
-
- The setting of the switch can, of course, be made conditional on the
- calling host.
-
-21. There is now support for the libradius library that comes with FreeBSD.
- This is an alternative to the radiusclient library that Exim already
- supports. To use the FreeBSD library, you need to set
-
- RADIUS_LIB_TYPE=RADLIB
-
- in Local/Makefile, in addition to RADIUS_CONFIGURE_FILE, and you probably
- also need -libradius in EXTRALIBS.
-
-
-Version 4.42
+ The result of that expansion would be "6". The maximum of a list of numbers
+ can be found:
+
+ ${reduce {3:0:9:4:6}{0}{${if >{$item}{$value}{$item}{$value}}}}
+
+ At the end of a ${reduce expansion, the values of $item and $value is
+ restored to what they were before.
+
+
+Version 4.66
------------
- 1. The "personal" filter test is brought up-to-date with recommendations from
- the Sieve specification: (a) The list of non-personal From: addresses now
- includes "listserv", "majordomo", and "*-request"; (b) If the message
- contains any header line starting with "List=-" it is treated as
- non-personal.
+No new features were added to 4.66.
- 2. The Sieve functionality has been extended to support the "copy" and
- "vacation" extensions, and comparison tests.
- 3. There is now an overall timeout for performing a callout verification. It
- defaults to 4 times the callout timeout, which applies to individual SMTP
- commands during the callout. The overall timeout applies when there is more
- than one host that can be tried. The timeout is checked before trying the
- next host. This prevents very long delays if there are a large number of
- hosts and all are timing out (e.g. when the network connections are timing
- out). The value of the overall timeout can be changed by specifying an
- additional sub-option for "callout", called "maxwait". For example:
+Version 4.65
+------------
+
+No new features were added to 4.65.
- verify = sender/callout=5s,maxwait=20s
- 4. Changes to the "personal" filter test:
+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.
- (1) The list of non-personal local parts in From: addresses has been
- extended to include "listserv", "majordomo", "*-request", and "owner-*",
- taken from the Sieve specification recommendations.
+ 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.
- (2) If the message contains any header line starting with "List-" it is
- treated as non-personal.
+ 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.
- (3) The test for "circular" in the Subject: header line has been removed
- because it now seems ill-conceived.
+ 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. The autoreply transport has a new option called never_mail. This is an
- address list. If any run of the transport creates a message with a
- recipient that matches any item in the list, that recipient is quietly
- discarded. If all recipients are discarded, no message is created.
+ 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.
-Version 4.40
+ 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
+------------
+
+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
------------
-The documentation is up-to-date for the 4.40 release. What follows here is a
-brief list of the new features that have been added since 4.30.
+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.
- 1. log_incoming_interface affects more log lines.
+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.
- 2. New ACL modifier "control = submission".
- 3. CONFIGURE_OWNER can be set at build time to define an alternative owner for
- the configuration file, in addition to root and exim.
+Version 4.61
+------------
+
+The documentation is up-to-date for the 4.61 release. Major new features since
+the 4.60 release are:
- 4. Added expansion variables $body_zerocount, $recipient_data, and
- $sender_data.
+. An option called disable_ipv6, to disable the use of IPv6 completely.
- 5. The time of last modification of the "new" subdirectory is now used as the
- "mailbox time last read" when there is a quota error for a maildir
- delivery.
+. An increase in the number of ACL variables to 20 of each type.
- 6. The special item "+ignore_unknown" may now appear in host lists.
+. 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.
- 7. The special domain-matching patterns @mx_any, @mx_primary, and
- @mx_secondary can now be followed by "/ignore=<ip list>".
+. The default for rfc1413_query_timeout has been changed from 30s to 5s.
- 8. New expansion conditions: match_domain, match_address, match_local_part,
- lt, lti, le, lei, gt, gti, ge, and new expansion operators time_interval,
- eval10, and base62d.
+. It is possible to use setclassresources() on some BSD OS to control the
+ resources used in pipe deliveries.
- 9. New lookup type called "iplsearch".
+. A new ACL modifier called add_header, which can be used with any verb.
-10. New log selectors ident_timeout, tls_certificate_verified, queue_time,
- deliver_time, outgoing_port, return_path_on_delivery.
+. More errors are detectable in retry rules.
-11. New global options smtp_active_hostname and tls_require_ciphers.
+There are a number of other additions too.
-12. Exinext has -C and -D options.
-13. "domainlist_cache" forces caching of an apparently variable list.
+Version 4.60
+------------
+
+The documentation is up-to-date for the 4.60 release. Major new features since
+the 4.50 release are:
-14. For compatibility with Sendmail, the command line option -prval:sval
- is equivalent to -oMr rval -oMs sval.
+. Support for SQLite.
-15. New callout options use_sender and use_postmaster for use when verifying
- recipients.
+. Support for IGNOREQUOTA in LMTP.
-16. John Jetmore's "exipick" utility has been added to the distribution.
+. Extensions to the "submission mode" features.
-17. The TLS code now supports CRLs.
+. Support for Client SMTP Authorization (CSA).
-18. The dnslookup router and the dnsdb lookup type now support the use of SRV
- records.
+. Support for ratelimiting hosts and users.
-19. The redirect router has a new option called qualify_domain.
+. New expansion items to help with the BATV "prvs" scheme.
-20. exigrep's output now also includes lines that are not related to any
- particular message, but which do match the pattern.
+. A "match_ip" condition, that matches an IP address against a list.
-21. New global option write_rejectlog. If it is set false, Exim no longer
- writes anything to the reject log.
+There are many more minor changes.
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git://git.exim.org / users / jgh / exim.git / blobdiff