This module matches the netfilter mark field associated with a connection
(which can be set using the \fBCONNMARK\fR target below).
.TP
[\fB!\fP] \fB--mark\fR \fIvalue\fR[\fB/\fR\fImask\fR]
Matches packets in connections with the given mark value (if a mask is
specified, this is logically ANDed with the mark before the comparison).