the OpenFlow controller. It takes one of the following forms:
.RS
-.TP
-\fBssl:\fIhost\fR[\fB:\fIport\fR]
-The specified SSL \fIport\fR (default: 6633) on the given remote
-\fIhost\fR. The \fB--private-key\fR, \fB--certificate\fR, and
-\fB--ca-cert\fR options are mandatory when this form is used.
+.IP "\fBssl:\fIip\fR[\fB:\fIport\fR]"
+The specified SSL \fIport\fR (default: 6633) on the host at the given
+\fIip\fR, which must be expressed as an IP address (not a DNS name).
+The \fB--private-key\fR, \fB--certificate\fR, and \fB--ca-cert\fR
+options are mandatory when this form is used.
-.TP
-\fBtcp:\fIhost\fR[\fB:\fIport\fR]
-The specified TCP \fIport\fR (default: 6633) on the given remote
-\fIhost\fR.
+.IP "\fBtcp:\fIip\fR[\fB:\fIport\fR]"
+The specified TCP \fIport\fR (default: 6633) on the host at the given
+\fIip\fR, which must be expressed as an IP address (not a DNS name).
.TP
\fBunix:\fIfile\fR
is given, the default is in-band control.
.TP
-\fB--netflow=\fIhost\fB:\fIport\fR
-Configures the given UDP \fIport\fR on the specified IP \fIhost\fR as
-a recipient of NetFlow messages for expired flows.
+\fB--netflow=\fIip\fB:\fIport\fR
+Configures the given UDP \fIport\fR on the specified IP \fIip\fR as
+a recipient of NetFlow messages for expired flows. The \fIip\fR must
+be specified numerically, not as a DNS name.
This option may be specified multiple times to configure additional
NetFlow collectors.