.Op Fl e Ar defaultdomain
.Op Fl f
.Op Fl i Ar networks
+.Op Fl I
.Op Fl m
.Op Fl M
.Op Fl P Ar pidfile
flags will append to the list.
For example, if you list all your internal networks, no outgoing emails
will be filtered.
+.It Fl I
+Ignores messages if the sender has authenticated via SMTP AUTH.
.It Fl m
Disables modification of the
.Ql Subject: