+
+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
+
+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)
+
+If compiled with EXPERIMENTAL_XCLIENT=yes :-
+
+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
+
git://git.exim.org / exim.git / blobdiff