--- bin/smtp-vilter/smtp-vilter.conf.5.orig	Sun Jan 21 13:09:38 2007
+++ bin/smtp-vilter/smtp-vilter.conf.5	Fri Oct 23 16:09:16 2009
@@ -103,6 +103,27 @@ Define the path from where backend are loaded.
 Define the filename path to the configuration file for backend <backend>.
 Note that this command must be preceeded by the backend command.
 .El
+.Bl -ohang
+.It Em header-options=<header-options>
+Control various features of the artifical header used to forward
+messages to a spam detection backend.
+Note that this header is entirely internal and is NOT visible to the MTA or
+the end recipient.
+.Pp
+At present there is only one option, which is to indicate the sender's SASL
+authentication status as reported by the MTA:
+.El
+.Bl -ohang -offset indent
+.It Pa header-options=0
+ignore SASL authentication status (default)
+.It Pa header-options=1
+if the sender successfully signed in then insert a tag of the form
+"(Authenticated sender: user@domain)" in the received header.
+.El
+.Pp
+The latter behaviour emulates Postfix's "smtpd_sasl_authenticated_header"
+option, and enables a (suitably configured) spam detection backend to apply 
+different rules for trusted senders.
 .Sh STRATEGIES
 .Bl -ohang
 .It Em virus-strategy=<strategy>