X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/2983e1a616058c03b57f1ab32a691f8b8ff9764e..f70940c9489d0ff5dc44db5ba5ed5258a8fe8772:/doc/doc-txt/experimental-spec.txt?ds=sidebyside diff --git a/doc/doc-txt/experimental-spec.txt b/doc/doc-txt/experimental-spec.txt index 599d2bb1b..f61db629e 100644 --- a/doc/doc-txt/experimental-spec.txt +++ b/doc/doc-txt/experimental-spec.txt @@ -292,62 +292,6 @@ These four steps are explained in more details below. -SRS (Sender Rewriting Scheme) Support (using libsrs_alt) --------------------------------------------------------------- -See also the main docs, for an alternative native support implementation. - -Exim can be built with SRS support using Miles Wilton's -libsrs_alt library. The current version of the supported -library is 0.5, there are reports of 1.0 working. - -In order to use SRS, you must get a copy of libsrs_alt from - -https://opsec.eu/src/srs/ - -(not the original source, which has disappeared.) - -Unpack the tarball, then refer to MTAs/README.EXIM -to proceed. You need to set - -EXPERIMENTAL_SRS_ALT=yes - -in your Local/Makefile. - -The built-in support, included by SUPPORT_SRS, -shuold *not* be enabled if you wish to use the libsrs_alt -version. - -The following main-section options become available: - srs_config string - srs_hashlength int - srs_hashmin int - srs_maxage int - srs_secrets string - srs_usehash bool - srs_usetimestamp bool - -The redirect router gains these options (all of type string, unset by default): - srs - srs_alias - srs_condition - srs_dbinsert - srs_dbselect - -The following variables become available: - $srs_db_address - $srs_db_key - $srs_orig_recipient - $srs_orig_sender - $srs_recipient - $srs_status - -The predefined feature-macro _HAVE_SRS will be present. -Additional delivery log line elements, tagged with "SRS=" will show the srs sender. -For configuration information see https://github.com/Exim/exim/wiki/SRS . - - - - DCC Support -------------------------------------------------------------- Distributed Checksum Clearinghouse; http://www.rhyolite.com/dcc/ @@ -466,52 +410,6 @@ Rationale: Note that non-RFC-documented field names and data types are used. -LMDB Lookup support -------------------- -LMDB is an ultra-fast, ultra-compact, crash-proof key-value embedded data store. -It is modeled loosely on the BerkeleyDB API. You should read about the feature -set as well as operation modes at https://symas.com/products/lightning-memory-mapped-database/ - -LMDB single key lookup support is provided by linking to the LMDB C library. -The current implementation does not support writing to the LMDB database. - -Visit https://github.com/LMDB/lmdb to download the library or find it in your -operating systems package repository. - -If building from source, this description assumes that headers will be in -/usr/local/include, and that the libraries are in /usr/local/lib. - -1. In order to build exim with LMDB lookup support add or uncomment - -EXPERIMENTAL_LMDB=yes - -to your Local/Makefile. (Re-)build/install exim. exim -d should show -Experimental_LMDB in the line "Support for:". - -EXPERIMENTAL_LMDB=yes -LDFLAGS += -llmdb -# CFLAGS += -I/usr/local/include -# LDFLAGS += -L/usr/local/lib - -The first line sets the feature to include the correct code, and -the second line says to link the LMDB libraries into the -exim binary. The commented out lines should be uncommented if you -built LMDB from source and installed in the default location. -Adjust the paths if you installed them elsewhere, but you do not -need to uncomment them if an rpm (or you) installed them in the -package controlled locations (/usr/include and /usr/lib). - -2. Create your LMDB files, you can use the mdb_load utility which is -part of the LMDB distribution our your favourite language bindings. - -3. Add the single key lookups to your exim.conf file, example lookups -are below. - -${lookup{$sender_address_domain}lmdb{/var/lib/baruwa/data/db/relaydomains.mdb}{$value}} -${lookup{$sender_address_domain}lmdb{/var/lib/baruwa/data/db/relaydomains.mdb}{$value}fail} -${lookup{$sender_address_domain}lmdb{/var/lib/baruwa/data/db/relaydomains.mdb}} - - Queuefile transport ------------------- Queuefile is a pseudo transport which does not perform final delivery. @@ -615,7 +513,9 @@ standard header. add_header = :at_start:${authresults {}} Note that it would be wise to strip incoming messages of A-R headers - that claim to be from our own . + that claim to be from our own . Eg: + + remove_header = \N^(?i)Authentication-Results\s*::\s*example.org;\N There are four new variables: @@ -685,7 +585,7 @@ used via the transport in question. Dovecot authenticator via inet socket ------------------------------------- +-------------------------------------------------------------- If Dovecot is configured similar to :- service auth { @@ -712,29 +612,88 @@ and a whitespace-separated port number must be given. -Twophase queue run fast ramp ----------------------------- -To include this feature, add to Local/Makefile: - EXPERIMENTAL_QUEUE_RAMP=yes -If the (added for this feature) main-section option "queue_fast_ramp" (boolean) -is set, and a two-phase ("-qq") queue run finds, during the first phase, a -suitably large number of message routed for a given host - then (subject to -the usual queue-runner resource limits) delivery for that host is initiated -immediately, overlapping with the remainder of the first phase. +Logging protocol unusual states +--------------------------------------------------------------- +An extra log_selector, "protocol_detail" has been added in the default build. +The name may change in future, hence the Experimenal status. + +Currrently the only effect is to enable logging, under TLS, +of a TCP RST received directly after a QUIT (in server mode). + +Outlook is consistently doing this; not waiting for the SMTP response +to its QUIT, not properly closing the TLS session and not properly closing +the TCP connection. Previously this resulted is an error from SSL_write +being logged. + + + +Limits ESMTP extension +--------------------------------------------------------------- +Per https://datatracker.ietf.org/doc/html/draft-freed-smtp-limits-01 +(as of 2023/08/04, version -05 has been published. It does not seems +to be substantively different.) + +If compiled with EXPERIMENTAL_ESMTP_LIMITS=yes :- + +As a server, Exim will advertise, in the EHLO response, the limit for RCPT +commands set by the recipients_max main-section config option (if it is set), +and the limit for MAIL commands set by the smtp_accept_max_per_connection +option. + +Note that as of writing, smtp_accept_max_per_connection is expanded but +recipients_max is not. + +A new main-section option "limits_advertise_hosts" controls whether +the limits are advertised; the default for the option is "*". + +As a client, Exim will: + + - note an advertised MAILMAX; the lower of the value given and the + value from the transport connection_max_messages option is used. + + - note an advertised RCPTMAX; the lower of the + value given and the value from the transport max_rcpt option is used. + Parallisation of transactions is not done if due to a RCPTMAX, unlike + max_rcpt. + + - note an advertised RCPTDOMAINMAX, and behave as if the transport + multi_domains option was set to false. The value advertised is ignored. + +Values advertised are only noted for TLS connections and ones for which +the server does not advertise TLS support. + + + +XCLIENT proxy support +--------------------------------------------------------------- +Per https://www.postfix.org/XCLIENT_README.html -This is incompatible with queue_run_in_order. +XCLIENT is an ESMTP extension supporting an inbound proxy. +The only client immplementation known is in Nginx +(https://nginx.org/en/docs/mail/ngx_mail_proxy_module.html) -The result should be a faster startup of deliveries when a large queue is -present and reasonable numbers of messages are routed to common hosts; this -could be a smarthost case, or delivery onto the Internet where a large proportion -of recipients hapen to be on a Gorilla-sized provider. +If compiled with EXPERIMENTAL_XCLIENT=yes :- -As usual, the presence of a configuration option is associated with a -predefined macro, making it possible to write portable configurations. -For this one, the macro is _OPT_MAIN_QUEUE_FAST_RAMP. +As a server, Exim will advertise XCLIENT support (conditional on a new option +"hosts_xclient") and service XCLIENT commands with parameters + ADDR + NAME + PORT + LOGIN + DESTADDR + DESTPORT +A fresh HELO/EHLO is required after a succesful XCLIENT, and the usual +values are derived from that (making the HELO and PROTO paramemters redundant). +An XCLIENT command must give both ADDR and PORT parameters if no previous +XCLIENT has succeeded in the SMTP session. +After a success: + $proxy_session variable becomes "yes" + $proxy_local_address, $proxy_local_port have the proxy "inside" values + $proxy_external_address, $proxy_external_port have the proxy "outside" values + $sender_host_address, $sender_host_port have the remot client values -------------------------------------------------------------- End of file