-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.45 2005/05/23 16:58:55 fanf2 Exp $
+$Cambridge: exim/doc/doc-txt/NewStuff,v 1.54 2005/06/29 14:29:05 fanf2 Exp $
New Features in Exim
--------------------
ratelimit = <m> / <p> / <options> / <key>
- If the average client sending rate is greater than m messages per time
- period p then the condition is true, otherwise it is false.
+ If the average client sending rate is less than m messages per time
+ period p then the condition is false, otherwise it is true.
The parameter p is the smoothing time constant, in the form of an Exim
time interval e.g. 8h for eight hours. A larger time constant means it
cdb {DB/ratelimits.cdb} \
{$value} {RATELIMIT} }
+ Warning: if you have a busy server with a lot of ratelimit tests,
+ especially with the per_rcpt option, you may suffer from a performance
+ bottleneck caused by locking on the ratelimit hints database. Apart from
+ making your ACLs less complicated, you can reduce the problem by using a
+ RAM disk for Exim's hints directory, /var/spool/exim/db/. However this
+ means that Exim will lose its hints data after a reboot (including retry
+ hints, the callout cache, and ratelimit data).
+
+TK/01 Added an 'spf' lookup type that will return an SPF result for a given
+ email address (the key) and an IP address (the database):
+
+ ${lookup {tom@duncanthrax.net} spf{217.115.139.137}}
+
+ The lookup will return the same result strings as they can appear in
+ $spf_result (pass,fail,softfail,neutral,none,err_perm,err_temp). The
+ lookup is armored in EXPERIMENTAL_SPF. Currently, only IPv4 addresses
+ are supported.
+
+ Patch submitted by Chris Webb <chris@arachsys.com>.
+
+PH/02 There's a new verify callout option, "fullpostmaster", which first acts
+ as "postmaster" and checks the recipient <postmaster@domain>. If that
+ fails, it tries just <postmaster>, without a domain, in accordance with
+ the specification in RFC 2821.
+
+PH/03 The action of the auto_thaw option has been changed. It no longer applies
+ to frozen bounce messages.
+
+TK/02 There are two new expansion items to help with the implementation of
+ the BATV "prvs" scheme in an Exim configuration:
+
+
+ ${prvs {<ADDRESS>}{<KEY>}{[KEYNUM]}}
+
+ The "prvs" expansion item takes three arguments: A qualified RFC2821
+ email address, a key and an (optional) key number. All arguments are
+ expanded before being used, so it is easily possible to lookup a key
+ and key number using the address as the lookup key. The key number is
+ optional and defaults to "0". The item will expand to a "prvs"-signed
+ email address, to be typically used with the "return_path" option on
+ a smtp transport. The decision if BATV should be used with a given
+ sender/recipient pair should be done on router level, to avoid having
+ to set "max_rcpt = 1" on the transport.
+
+
+ ${prvscheck {<ADDRESS>}{<SECRET>}{<RETURN_STRING>}}
+
+ The "prvscheck" expansion item takes three arguments. Argument 1 is
+ expanded first. When the expansion does not yield a SYNTACTICALLY
+ valid "prvs"-scheme address, the whole "prvscheck" item expands to
+ the empty string. If <ADDRESS> is a "prvs"-encoded address after
+ expansion, two expansion variables are set up:
+
+ $prvscheck_address Contains the "prvs"-decoded version of
+ the address from argument 1.
+
+ $prvscheck_keynum Contains the key number extracted from
+ the "prvs"-address in argument 1.
+
+ These two variables can be used in the expansion code of argument 2
+ to retrieve the <SECRET>. The VALIDITY of the "prvs"-signed address
+ is then checked. The result is stored in yet another expansion
+ variable:
+
+ $prvscheck_result Contains the result of a "prvscheck"
+ expansion: Unset (the empty string) for
+ failure, "1" for success.
+
+ The "prvscheck" expansion expands to the empty string if <ADDRESS>
+ is not a SYNTACTICALLY valid "prvs"-scheme address. Otherwise,
+ argument 3 defines what "prvscheck" expands to: If argument 3
+ is the empty string, "prvscheck" expands to the decoded version
+ of the address (no matter if it is CRYPTOGRAPHICALLY valid or not).
+ If argument 3 expands to a non-empty string, "prvscheck" expands
+ to that string.
+
+
+ Usage example
+ -------------
+
+ Macro:
+
+ PRVSCHECK_SQL = ${lookup mysql{SELECT secret FROM batv_prvs WHERE \
+ sender='${quote_mysql:$prvscheck_address}'}{$value}}
+
+ RCPT ACL:
+
+ # Bounces: drop unsigned addresses for BATV senders
+ deny message = This address does not send an unsigned reverse path.
+ senders = :
+ recipients = +batv_recipients
+
+ # Bounces: In case of prvs-signed address, check signature.
+ deny message = Invalid reverse path signature.
+ senders = :
+ condition = ${prvscheck {$local_part@$domain}{PRVSCHECK_SQL}{1}}
+ !condition = $prvscheck_result
+
+ Top-Level Router:
+
+ batv_redirect:
+ driver = redirect
+ data = ${prvscheck {$local_part@$domain}{PRVSCHECK_SQL}{}}
+
+ Transport (referenced by router that makes decision if
+ BATV is applicable):
+
+ external_smtp_batv:
+ driver = smtp
+ return_path = ${prvs {$return_path} \
+ {${lookup mysql{SELECT \
+ secret FROM batv_prvs WHERE \
+ sender='${quote_mysql:$sender_address}'} \
+ {$value}fail}}}
+
+PH/04 There are two new options that control the retrying done by the daemon
+ at startup when it cannot immediately bind a socket (typically because
+ the socket is already in use). The default values reproduce what were
+ built-in constants previously: daemon_startup_retries defines the number
+ of retries after the first failure (default 9); daemon_startup_sleep
+ defines the length of time to wait between retries (default 30s).
+
+PH/05 There is now a new ${if condition called "match_ip". It is similar to
+ match_domain, etc. It must be followed by two argument strings. The first
+ (after expansion) must be an IP address or an empty string. The second
+ (after expansion) is a restricted host list that can match only an IP
+ address, not a host name. For example:
+
+ ${if match_ip{$sender_host_address}{1.2.3.4:5.6.7.8}{...}{...}}
+
+ The specific types of host list item that are permitted in the list are
+ shown below. Consult the manual section on host lists for further
+ details.
+
+ . An IP address, optionally with a CIDR mask.
+
+ . A single asterisk matches any IP address.
+
+ . An empty item matches only if the IP address is empty. This could be
+ useful for testing for a locally submitted message or one from specific
+ hosts in a single test such as
+
+ ${if match_ip{$sender_host_address}{:4.3.2.1:...}{...}{...}}
+
+ where the first item in the list is the empty string.
+
+ . The item @[] matches any of the local host's interface addresses.
+
+ . Lookups are assumed to be "net-" style lookups, even if "net-" is not
+ specified. Thus, the following are equivalent:
+
+ ${if match_ip{$sender_host_address}{lsearch;/some/file}...
+ ${if match_ip{$sender_host_address}{net-lsearch;/some/file}...
+
+ You do need to specify the "net-" prefix if you want to specify a
+ specific address mask, for example, by using "net24-".
+
+PH/06 The "+all" debug selector used to set the flags for all possible output;
+ it is something that people tend to use semi-automatically when
+ generating debug output for me or for the list. However, by including
+ "+memory", an awful lot of output that is very rarely of interest was
+ generated. I have changed this so that "+all" no longer includes
+ "+memory". However, "-all" still turns everything off.
+
Version 4.51
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git://git.exim.org / exim.git / blobdiff