.IP "\fBpssl:\fR[\fIport\fR][\fB:\fIip\fR]"
.IQ "\fBptcp:\fR[\fIport\fR][\fB:\fIip\fR]"
Listens for OpenFlow connections on \fIport\fR.  The default
\fIport\fR is 6653.  By default, connections
are allowed from any IPv4 address.  Specify \fIip\fR as an IPv4
address or a bracketed IPv6 address (e.g. \fBptcp:6653:[::1]\fR).  DNS
names may not be used.  For \fBpssl\fR, the
\fB\-\-private\-key\fR,\fB\-\-certificate\fR, and \fB\-\-ca\-cert\fR
options are mandatory.
.IP
.
.IP "\fBpunix:\fIfile\fR"
Listens for OpenFlow connections on the Unix domain server socket
named \fIfile\fR.