Here is a patch to remove mention of filters from smtpd.conf -- Edgar Pettijohn
Index: smtpd.conf.5 =================================================================== RCS file: /cvs/src/usr.sbin/smtpd/smtpd.conf.5,v retrieving revision 1.165 diff -u -p -u -r1.165 smtpd.conf.5 --- smtpd.conf.5 31 Aug 2016 16:39:24 -0000 1.165 +++ smtpd.conf.5 10 Sep 2016 20:52:08 -0000 @@ -609,20 +609,6 @@ For example: expire 4d # expire after 4 days expire 10h # expire after 10 hours .Ed -.It Ic filter Ar name filter Op Ar arguments -Specify a filter with the given -.Ar name -and the program -.Ar filter -using the given filter -.Ar arguments . -Filters are used to hook into the SMTP dialog and provide additional filtering -options for -.Xr smtpd 8 . -.It Ic filter Ar name Ic chain Ar filter Ar ... -Specify a filter chain with the given -.Ar name -and filters. .It Xo .Ic limit session .Brq Cm max-rcpt | max-mails @@ -661,14 +647,12 @@ of inflight envelopes falls below Changing the default value might degrade performance. .It Xo .Ic listen on socket -.Op Ic filter Ar name .Op Ic mask-source .br .Bk -words .Ic listen on Ar interface .Op Ar family .Op Ic port Ar port -.Op Ic filter Ar name .Op Ic tls | tls-require | tls-require verify | smtps | secure .Op Ic pki Ar pkiname .Op Ic ca Ar caname @@ -719,12 +703,6 @@ Accepted values are and .Ic inet6 . .Pp -A -.Ic filter -may be specified to use a filter or filter chain with the given -.Ar name -on SMTP transactions. -.Pp Secured connections are provided either using STARTTLS .Pq Ic tls , by default on port 25,
