.IP "\fBssl:\fIip\fR[\fB:\fIport\fR]"
.IQ "\fBtcp:\fIip\fR[\fB:\fIport\fR]"
The specified \fIport\fR on the host at the given \fIip\fR, which must
be expressed as an IP address (not a DNS name).  For \fBssl\fR, the
\fB\-\-private\-key\fR, \fB\-\-certificate\fR, and \fB\-\-ca\-cert\fR
options are mandatory.
.IP
If \fIport\fR is not specified, it currently defaults to 6633.  In the
future, the default will change to 6653, which is the IANA-defined
value.
.TP
\fBunix:\fIfile\fR
The Unix domain server socket named \fIfile\fR.