-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.17 2004/11/24 16:36:19 ph10 Exp $
+$Cambridge: exim/doc/doc-txt/NewStuff,v 1.97 2006/03/16 11:51:09 ph10 Exp $
New Features in Exim
--------------------
updated when there is a relatively large batch of changes). The doc/ChangeLog
file contains a listing of all changes, including bug fixes.
-
-Version 4.44
+Version 4.61
------------
- 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.
-
- 2. The "control=submission" facility has a new option /sender_retain. This
- has the effect of setting local_sender_retain true and local_from_check
- false for the incoming message in which it is encountered.
-
- 3. $recipients is now available in the predata ACL (oversight).
-
- 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.
-
- 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.
-
- 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:
-
- verify = sender/callout=5s,connect=1s
-
- If not specified, it defaults to the general timeout value.
-
- 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:
-
- qualify the address was unqualified (no domain), and the message
- was neither local nor came from an exempted host;
-
- route routing failed;
-
- mail routing succeeded, and a callout was attempted; rejection
- occurred at or before the MAIL command (that is, on initial
- connection, HELO, or MAIL);
-
- recipient the RCPT command in a callout was rejected;
-
- postmaster the postmaster check in a callout was rejected.
-
- The main use of these variables is expected to be to distinguish between
- rejections of MAIL and rejections of RCPT.
-
- 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.
-
- 9. $host_address is now set to the target address during the checking of
- ignore_target_hosts.
-
-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.
-
- 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:
-
- condition = ${if > {$spool_space}{50000}{yes}{no}}
-
- 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.
-
-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
-
- condition = ${if eq {$acl_m4}{1}{yes}{no}}
-
- or the shorter form
-
- condition = ${if eq {$acl_m4}{1}{yes}}
-
- (because the second string has always defaulted to ""), you can now write
-
- condition = ${if eq {$acl_m4}{1}}
-
- Previously this was a syntax error.
-
-12. There is a new "record type" that can be specified in dnsdb lookups. It
- is "zns" (for "zone NS"). It performs a lookup for NS records on the given
- domain, but if none are found, it removes the first component of the domain
- name, and tries again. This process continues until NS records are found
- or there are no more components left (or there's a DNS error). In other
- words, it may return the name servers for a top-level domain, but it never
- returns the root name servers. If there are no NS records for the top-level
- domain, the lookup fails.
-
- For example, ${lookup dnsdb{zns=xxx.quercite.com}} returns the name
- servers for quercite.com, whereas ${lookup dnsdb{zns=xxx.edu}} returns
- the name servers for edu, assuming in each case that there are no NS
- records for the full domain name.
-
- You should be careful about how you use this lookup because, unless the
- top-level domain does not exist, the lookup will always return some host
- names. The sort of use to which this might be put is for seeing if the name
- servers for a given domain are on a blacklist. You can probably assume that
- the name servers for the high-level domains such as .com or .co.uk are not
- going to be on such a list.
-
-13. Another new "record type" is "mxh"; this looks up MX records just as "mx"
- does, but it returns only the names of the hosts, omitting the priority
- values.
-
-14. It is now possible to specify a list of domains or IP addresses to be
- looked up in a dnsdb lookup. The list is specified in the normal Exim way,
- with colon as the default separator, but with the ability to change this.
- For example:
-
- ${lookup dnsdb{one.domain.com:two.domain.com}}
- ${lookup dnsdb{a=one.host.com:two.host.com}}
- ${lookup dnsdb{ptr = <; 1.2.3.4 ; 4.5.6.8}}
-
- In order to retain backwards compatibility, there is one special case: if
- the lookup type is PTR and no change of separator is specified, Exim looks
- to see if the rest of the string is precisely one IPv6 address. In this
- case, it does not treat it as a list.
-
- The data from each lookup is concatenated, with newline separators (by
- default - see 14 below), in the same way that multiple DNS records for a
- single item are handled.
-
- The lookup fails only if all the DNS lookups fail. As long as at least one
- of them yields some data, the lookup succeeds. However, if there is a
- temporary DNS error for any of them, the lookup defers.
-
-15. It is now possible to specify the character to be used as a separator when
- a dnsdb lookup returns data from more than one DNS record. The default is a
- newline. To specify a different character, put '>' followed by the new
- character at the start of the query. For example:
-
- ${lookup dnsdb{>: a=h1.test.ex:h2.test.ex}}
- ${lookup dnsdb{>| mxh=<;m1.test.ex;m2.test.ex}}
-
- It is permitted to specify a space as the separator character. Note that
- more than one DNS record can be found for a single lookup item; this
- feature is relevant even when you do not specify a list.
+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.
+
+PH/20 There are now two options for the exicyclog script:
- The same effect could be achieved by wrapping the lookup in ${tr...}; this
- feature is just a syntactic simplification.
+ -k <days> specifies the number of old logs to keep, overriding the
+ default that is set when Exim is built.
+
+ -l <path> specifies the log file path, in the same format as the
+ log_file_path option (e.g. /var/log/exim_%slog), again,
+ overriding the script's default - which is to find the setting
+ from Exim's configuration.
-16. It is now possible to supply a list of domains and/or IP addresses to be
- lookup up in a DNS blacklist. Previously, only a single domain name could
- be given, for example:
- dnslists = black.list.tld/$sender_host_name
-
- What follows the slash can now be a list. As with all lists, the default
- separator is a colon. However, because this is a sublist within the list of
- DNS blacklist domains, it is necessary either to double the separators like
- this:
-
- dnslists = black.list.tld/name.1::name.2
-
- or to change the separator character, like this:
-
- dnslists = black.list.tld/<;name.1;name.2
-
- If an item in the list is an IP address, it is inverted before the DNS
- blacklist domain is appended. If it is not an IP address, no inversion
- occurs. Consider this condition:
-
- dnslists = black.list.tls/<;192.168.1.2;a.domain
-
- The DNS lookups that occur are for
-
- 2.1.168.192.black.list.tld and a.domain.black.list.tld
-
- Once a DNS record has been found (that matches a specific IP return
- address, if specified), no further lookups are done.
-
-17. The log selector queue_time_overall causes Exim to output the time spent on
- the queue as an addition to the "Completed" message. Like queue_time (which
- puts the queue time on individual delivery lines), the time is tagged with
- "QT=", and it is measured from the time that the message starts to be
- received, so it includes the reception time.
-
-
-Version 4.43
+Version 4.60
------------
- 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.
-
- 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:
-
- 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.
-
- 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.
-
- xx.1 Using cyrus_sasl as a server
-
- The cyrus_sasl authenticator has four private options. It puts the username
- (on a successful authentication) into $1.
-
- server_hostname Type: string* Default: $primary_hostname
-
- 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.
-
- server_mech Type: string Default: public_name
-
- 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:
-
- 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:
-
- 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
-------------
-
- 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.
-
- 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:
-
- verify = sender/callout=5s,maxwait=20s
-
- 4. Changes to the "personal" filter test:
-
- (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) If the message contains any header line starting with "List-" it is
- treated as non-personal.
-
- (3) The test for "circular" in the Subject: header line has been removed
- because it now seems ill-conceived.
-
- 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.
-
-
-Version 4.40
-------------
-
-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. log_incoming_interface affects more log lines.
-
- 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.
-
- 4. Added expansion variables $body_zerocount, $recipient_data, and
- $sender_data.
-
- 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.
-
- 6. The special item "+ignore_unknown" may now appear in host lists.
-
- 7. The special domain-matching patterns @mx_any, @mx_primary, and
- @mx_secondary can now be followed by "/ignore=<ip list>".
-
- 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.
-
- 9. New lookup type called "iplsearch".
-
-10. New log selectors ident_timeout, tls_certificate_verified, queue_time,
- deliver_time, outgoing_port, return_path_on_delivery.
-
-11. New global options smtp_active_hostname and tls_require_ciphers.
-
-12. Exinext has -C and -D options.
-
-13. "domainlist_cache" forces caching of an apparently variable list.
+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.
****
git://git.exim.org / exim.git / blobdiff