The "state" extension is a subset of the "conntrack" module.
"state" allows access to the connection tracking state for this packet.
.TP
[\fB!\fP] \fB\-\-state\fP \fIstate\fP
Where state is a comma separated list of the connection states to match. Only a
subset of the states unterstood by "conntrack" are recognized: \fBINVALID\fP,
\fBESTABLISHED\fP, \fBNEW\fP, \fBRELATED\fP or \fBUNTRACKED\fP. For their
description, see the "conntrack" heading in this manpage.