TLS SNI support for OpenSSL ($tls_sni)

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

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 016f3f075f57c9bd7cf724d7eadfd50e784211e9..32e24ca8086811f1669b75f8f3c2436f835433f5 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -11888,6 +11888,24 @@ the value of the Distinguished Name of the certificate is made available in the
 value is retained during message delivery, except during outbound SMTP
 deliveries.
 
 value is retained during message delivery, except during outbound SMTP
 deliveries.
 

+.new
+.vitem &$tls_sni$&
+.vindex "&$tls_sni$&"
+.cindex "TLS" "Server Name Indication"
+When a TLS session is being established, if the client sends the Server
+Name Indication extension, the value will be placed in this variable.
+If the variable appears in &%tls_certificate%& then this option and
+&%tls_privatekey%& will be re-expanded early in the TLS session, to permit
+a different certificate to be presented (and optionally a different key to be
+used) to the client, based upon the value of the SNI extension.
+
+The value will be retained for the lifetime of the message, and not changed
+during outbound SMTP.
+
+This is currently only available when using OpenSSL, built with support for
+SNI.
+.wen
+

 .vitem &$tod_bsdinbox$&
 .vindex "&$tod_bsdinbox$&"
 The time of day and the date, in the format required for BSD-style mailbox
 .vitem &$tod_bsdinbox$&
 .vindex "&$tod_bsdinbox$&"
 The time of day and the date, in the format required for BSD-style mailbox