Callouts: a "hold" option for receipient-verify, which keeps the connection open...

[users/jgh/exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index e6a46c58a99625e24406ce37fdd20ee5fc2cbb0e..925b96324bd4d8c373376523e91f7fe683fa71d4 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -3869,12 +3869,12 @@ by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
 host to which Exim is connected supports TLS encryption.
 
 .new
-.vitem &%-MCt%&&~<&'IP&~address'&>&~<&'port'&>
+.vitem &%-MCt%&&~<&'IP&~address'&>&~<&'port'&>&~<&'cipher'&>
 .oindex "&%-MCt%&"
 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
 connection is being proxied by a parent process for handling TLS encryption.
-The pair of arguments give the local address and port being proxied.
+The arguments give the local address and port being proxied, and the TLS cipher.
 .wen
 
 .vitem &%-Mc%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
@@ -11042,9 +11042,14 @@ colon-separated components are permitted, each containing from one to four
 hexadecimal digits. There may be fewer than eight components if an empty
 component (adjacent colons) is present. Only one empty component is permitted.
 
-&*Note*&: The checks are just on the form of the address; actual numerical
-values are not considered. Thus, for example, 999.999.999.999 passes the IPv4
-check. The main use of these tests is to distinguish between IP addresses and
+.new
+&*Note*&: The checks used to be just on the form of the address; actual numerical
+values were not considered. Thus, for example, 999.999.999.999 passed the IPv4
+check.
+This is no longer the case.
+.wen
+
+The main use of these tests is to distinguish between IP addresses and
 host names, or between IPv4 and IPv6 addresses. For example, you could use
 .code
 ${if isip4{$sender_host_address}...
@@ -27213,10 +27218,12 @@ tls_require_ciphers = ${if =={$received_port}{25}\
 .cindex "TLS" "configuring an Exim server"
 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 unset, which means
-that STARTTLS is not advertised at all. This default is chosen because you
-need to set some other options in order to make TLS available, and also it is
-sensible for systems that want to use TLS only as a client.
+but not to any others. The default value of this option is *, which means
+that STARTTLS is alway advertised.  Set it to blank to never advertise;
+this is reasonble for systems that want to use TLS only as a client.
+
+If STARTTLS is to be used you
+need to set some other options in order to make TLS available.
 
 If a client issues a STARTTLS command and there is some configuration
 problem in the server, the command is rejected with a 454 error. If the client
@@ -30901,6 +30908,21 @@ command when performing the callout, instead of an empty address. There is no
 need to use this option unless you know that the called hosts make use of the
 sender when checking recipients. If used indiscriminately, it reduces the
 usefulness of callout caching.
+
+.vitem &*hold*&
+This option applies to recipient callouts only. For example:
+.code
+require  verify = recipient/callout=use_sender,hold
+.endd
+It causes the connection to be helod open and used for any further recipients
+and for eventual delivery (should that be done quickly).
+Doing this saves on TCP and SMTP startup costs, and TLS costs also
+when that is used for the connections.
+The advantage is only gained if there are no callout cache hits
+(which could be enforced by the no_cache option),
+if the use_sender option is used,
+if neither the random nor the use_postmaster option is used,
+and if no other callouts intervene.
 .endlist
 
 If you use any of the parameters that set a non-empty sender for the MAIL
@@ -31537,6 +31559,18 @@ av_scanner = f-protd:localhost 10200-10204
 .endd
 If you omit the argument, the default values show above are used.
 
+.new
+.vitem &%f-prot6d%&
+.cindex "virus scanners" "f-prot6d"
+The f-prot6d scanner is accessed using the FPSCAND protocol over TCP.
+One argument is taken, being a space-separated hostname and port number.
+For example:
+.code
+av_scanner = f-prot6d:localhost 10200
+.endd
+If you omit the argument, the default values show above are used.
+.wen
+
 .vitem &%fsecure%&
 .cindex "virus scanners" "F-Secure"
 The F-Secure daemon scanner (&url(http://www.f-secure.com)) takes one
@@ -35755,9 +35789,9 @@ down a single SMTP connection, an asterisk follows the IP address in the log
 lines for the second and subsequent messages.
 .new
 When two or more messages are delivered down a single TLS connection, the
-TLS-related information logged for the first message delivered
-(which may not be the earliest line in the log)
+DNS and some TLS-related information logged for the first message delivered
 will not be present in the log lines for the second and subsequent messages.
+TLS cipher information is still available.
 .wen
 
 .cindex "delivery" "cutthrough; logging"