.oindex "&%-MCS%&"
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
-SMTP SIZE option should be used on messages delivered down the existing
+ESMTP SIZE option should be used on messages delivered down the existing
connection.
.vitem &%-MCT%&
.cindex "8-bit characters"
.cindex "log" "selectors"
.cindex "log" "8BITMIME"
+.cindex "ESMTP extensions" 8BITMIME
This option causes Exim to send 8BITMIME in its response to an SMTP
EHLO command, and to accept the BODY= parameter on MAIL commands.
However, though Exim is 8-bit clean, it is not a protocol converter, and it
.option auth_advertise_hosts main "host list&!!" *
.cindex "authentication" "advertising"
.cindex "AUTH" "advertising"
+.cindex "ESMTP extensions" AUTH
If any server authentication mechanisms are configured, Exim advertises them in
response to an EHLO command only if the calling host matches this list.
Otherwise, Exim does not advertise AUTH.
.option chunking_advertise_hosts main "host list&!!" *
.cindex CHUNKING advertisement
.cindex "RFC 3030" "CHUNKING"
+.cindex "ESMTP extensions" CHUNKING
The CHUNKING extension (RFC3030) will be advertised in the EHLO message to
these hosts.
Hosts may use the BDAT command as an alternate to DATA.
.cindex "bounce messages" "success"
.cindex "DSN" "success"
.cindex "Delivery Status Notification" "success"
+.cindex "ESMTP extensions" DSN
DSN extensions (RFC3461) will be advertised in the EHLO message to,
and accepted from, these hosts.
Hosts may use the NOTIFY and ENVID options on RCPT TO commands,
TCP/IP. After expansion, the value must be a sequence of decimal digits,
optionally followed by K or M.
+.cindex "SIZE" "ESMTP extension, advertising"
+.cindex "ESMTP extensions" SIZE
+If nonzero the value will be advertised as a parameter to the ESMTP SIZE
+service extension keyword.
+
&*Note*&: This limit cannot be made to depend on a message's sender or any
other properties of an individual message, because it has to be advertised in
the server's response to EHLO. String expansion failure causes a temporary
.option pipelining_advertise_hosts main "host list&!!" *
.cindex "PIPELINING" "suppressing advertising"
+.cindex "ESMTP extensions" PIPELINING
This option can be used to suppress the advertisement of the SMTP
PIPELINING extension to specific hosts. See also the &*no_pipelining*&
control in section &<<SECTcontrols>>&. When PIPELINING is not advertised and
.option pipelining_connect_advertise_hosts main "host list&!!" *
.cindex "pipelining" "early connection"
.cindex "pipelining" PIPE_CONNECT
+.cindex "ESMTP extensions" X_PIPE_CONNECT
If Exim is built with the SUPPORT_PIPE_CONNECT build option
this option controls which hosts the facility is advertised to
and from which pipeline early-connection (before MAIL) SMTP
.option prdr_enable main boolean false
.cindex "PRDR" "enabling on server"
+.cindex "ESMTP extensions" PRDR
This option can be used to enable the Per-Recipient Data Response extension
to SMTP, defined by Eric Hall.
If the option is set, PRDR is advertised by Exim when operating as a server.
.option smtp_etrn_command main string&!! unset
.cindex "ETRN" "command to be run"
+.cindex "ESMTP extensions" ETRN
.vindex "&$domain$&"
If this option is set, the given command is run whenever an SMTP ETRN
command is received from a host that is permitted to issue such commands (see
.option smtputf8_advertise_hosts main "host list&!!" *
-.cindex "SMTPUTF8" "advertising"
+.cindex "SMTPUTF8" "ESMTP extension, advertising"
+.cindex "ESMTP extensions" SMTPUTF8
When Exim is built with support for internationalised mail names,
the availability thereof is advertised in
response to EHLO only to those client hosts that match this option. See
.cindex "TLS" "advertising"
.cindex "encryption" "on SMTP connection"
.cindex "SMTP" "encrypted connection"
+.cindex "ESMTP extensions" STARTTLS
When Exim is built with support for TLS encrypted connections, the availability
of the STARTTLS command to set up an encrypted session is advertised in
response to EHLO only to those client hosts that match this option. See
a spam score. This could be interpreted by a filter in the user's MUA. It is
not possible to discard a message at this stage.
-.cindex "SMTP" "SIZE"
+.cindex "SIZE" "ESMTP extension"
A problem might arise if the filter increases the size of a message that is
being sent down an SMTP connection. If the receiving SMTP server has indicated
support for the SIZE parameter, Exim will have sent the size of the message
.option hosts_avoid_pipelining smtp "host list&!!" unset
.cindex "PIPELINING" "avoiding the use of"
-Exim will not use the SMTP PIPELINING extension when delivering to any host
+.cindex "ESMTP extensions" PIPELINING
+Exim will not use the ESMTP PIPELINING extension when delivering to any host
that matches this list, even if the server host advertises PIPELINING support.
.option hosts_pipe_connect smtp "host list&!!" unset
.option hosts_try_prdr smtp "host list&!!" *
.cindex "PRDR" "enabling, optional in client"
+.cindex "ESMTP extensions" PRDR
This option provides a list of servers to which, provided they announce
PRDR support, Exim will attempt to negotiate PRDR
for multi-recipient messages.
.option size_addition smtp integer 1024
-.cindex "SMTP" "SIZE"
+.cindex "SIZE" "ESMTP extension"
.cindex "message" "size issue for transport filter"
.cindex "size" "of message"
.cindex "transport" "filter"
If both this option and &%tls_try_verify_hosts%& are unset
operation is as if this option selected all hosts.
-.option utf8_downconvert smtp integer!! unset
+.option utf8_downconvert smtp integer&!! unset
.cindex utf8 "address downconversion"
.cindex i18n "utf8 address downconversion"
If built with internationalization support,
other.
.cindex "AUTH" "description of"
+.cindex "ESMTP extensions" AUTH
Very briefly, the way SMTP authentication works is as follows:
.ilist
.section "Configuring an Exim server to use TLS" "SECID182"
.cindex "TLS" "configuring an Exim server"
+.cindex "ESMTP extensions" STARTTLS
When Exim has been built with TLS support, it advertises the availability of
the STARTTLS command to client hosts that match &%tls_advertise_hosts%&,
but not to any others. The default value of this option is *, which means
server certificate's DN. The remaining client configuration for TLS is all
within the &(smtp)& transport.
+.cindex "ESMTP extensions" STARTTLS
It is not necessary to set any options to have TLS work in the &(smtp)&
transport. If Exim is built with TLS support, and TLS is advertised by a
server, the &(smtp)& transport always tries to start a TLS session. However,
.vitem &*control&~=&~no_pipelining*&
.cindex "PIPELINING" "suppressing advertising"
+.cindex "ESMTP extensions" PIPELINING
This control turns off the advertising of the PIPELINING extension to SMTP in
the current session. To be useful, it must be obeyed before Exim sends its
response to an EHLO command. Therefore, it should normally appear in an ACL
.cindex "outgoing LMTP over TCP/IP"
.cindex "EHLO"
.cindex "HELO"
-.cindex "SIZE option on MAIL command"
+.cindex "SIZE" "option on MAIL command"
Outgoing SMTP and LMTP over TCP/IP is implemented by the &(smtp)& transport.
The &%protocol%& option selects which protocol is to be used, but the actual
processing is the same in both cases.
+.cindex "ESMTP extensions" SIZE
If, in response to its EHLO command, Exim is told that the SIZE
-parameter is supported, it adds SIZE=<&'n'&> to each subsequent MAIL
+extension is supported, it adds SIZE=<&'n'&> to each subsequent MAIL
command. The value of <&'n'&> is the message size plus the value of the
&%size_addition%& option (default 1024) to allow for additions to the message
such as per-transport header lines, or changes made in a
.section "The ETRN command" "SECTETRN"
.cindex "ETRN" "processing"
-RFC 1985 describes an SMTP command called ETRN that is designed to
+.cindex "ESMTP extensions" ETRN
+RFC 1985 describes an ESMTP command called ETRN that is designed to
overcome the security problems of the TURN command (which has fallen into
disuse). When Exim receives an ETRN command on a TCP/IP connection, it runs
the ACL specified by &%acl_smtp_etrn%& in order to decide whether the command
.section "MTA operations" SECTi18nMTA
.cindex SMTPUTF8 "ESMTP option"
+.cindex "ESMTP extensions" SMTPUTF8
The main configuration option &%smtputf8_advertise_hosts%& specifies
a host list. If this matches the sending host and
accept_8bitmime is true (the default) then the ESMTP option
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