document filter chains, which is essentially a way to declare a set of

related filters to be applied one after another

1 files changed, 10 insertions, 1 deletions

diff --git a/usr.sbin/smtpd/smtpd.conf.5 b/usr.sbin/smtpd/smtpd.conf.5
index 8605fc91e2b..086971a25c9 100644
--- a/usr.sbin/smtpd/smtpd.conf.5
+++ b/usr.sbin/smtpd/smtpd.conf.5
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: smtpd.conf.5,v 1.216 2019/08/11 13:57:37 gilles Exp $
+.\"	$OpenBSD: smtpd.conf.5,v 1.217 2019/08/11 14:13:14 gilles Exp $
 .\"
 .\" Copyright (c) 2008 Janne Johansson <jj@openbsd.org>
 .\" Copyright (c) 2009 Jacek Masiulaniec <jacekm@dobremiasto.net>
@@ -329,6 +329,15 @@ or set using either
 or using the
 .Ic hostname
 directive.
+.It Ic filter Ar chain\-name Ic chain Brq Ar filter-name Op , Ar ...
+Register a chain of filters named
+.Ar chain\-name
+and consisting of the filters listed from
+.Ar filter-name .
+Filters part of a filter chain are executed in order of declaration for
+each phase that they are registered for.
+A filter chain may be used in place of a filter for any directive but
+filter chains themselves.
 .It Ic filter Ar filter\-name Ic phase Ar phase\-name Ic match Ar conditions Ic disconnect Ar message
 Register builtin filter
 .Ar filter\-name