This module, when combined with connection tracking, allows access to the
connection tracking state for this packet/connection.
.TP
[\fB!\fP] \fB\-\-ctstate\fP \fIstatelist\fP
\fIstatelist\fP is a comma separated list of the connection states to match.
Possible states are listed below.
.TP
[\fB!\fP] \fB\-\-ctproto\fP \fIl4proto\fP
Layer-4 protocol to match (by number or name)
.TP
[\fB!\fP] \fB\-\-ctorigsrc\fP \fIaddress\fP[\fB/\fP\fImask\fP]
.TP
[\fB!\fP] \fB\-\-ctorigdst\fP \fIaddress\fP[\fB/\fP\fImask\fP]
.TP
[\fB!\fP] \fB\-\-ctreplsrc\fP \fIaddress\fP[\fB/\fP\fImask\fP]
.TP
[\fB!\fP] \fB\-\-ctrepldst\fP \fIaddress\fP[\fB/\fP\fImask\fP]
Match against original/reply source/destination address
.TP
[\fB!\fP] \fB\-\-ctorigsrcport\fP \fIport\fP[\fB:\fP\fIport\fP]
.TP
[\fB!\fP] \fB\-\-ctorigdstport\fP \fIport\fP[\fB:\fP\fIport\fP]
.TP
[\fB!\fP] \fB\-\-ctreplsrcport\fP \fIport\fP[\fB:\fP\fIport\fP]
.TP
[\fB!\fP] \fB\-\-ctrepldstport\fP \fIport\fP[\fB:\fP\fIport\fP]
Match against original/reply source/destination port (TCP/UDP/etc.) or GRE key.
Matching against port ranges is only supported in kernel versions above 2.6.38.
.TP
[\fB!\fP] \fB\-\-ctstatus\fP \fIstatelist\fP
\fIstatuslist\fP is a comma separated list of the connection statuses to match.
Possible statuses are listed below.
.TP
[\fB!\fP] \fB\-\-ctexpire\fP \fItime\fP[\fB:\fP\fItime\fP]
Match remaining lifetime in seconds against given value or range of values
(inclusive)
.TP
\fB\-\-ctdir\fP {\fBORIGINAL\fP|\fBREPLY\fP}
Match packets that are flowing in the specified direction. If this flag is not
specified at all, matches packets in both directions.
.PP
States for \fB\-\-ctstate\fP:
.TP
\fBINVALID\fP
The packet is associated with no known connection.
.TP
\fBNEW\fP
The packet has started a new connection or otherwise associated
with a connection which has not seen packets in both directions.
.TP
\fBESTABLISHED\fP
The packet is associated with a connection which has seen packets
in both directions.
.TP
\fBRELATED\fP
The packet is starting a new connection, but is associated with an
existing connection, such as an FTP data transfer or an ICMP error.
.TP
\fBUNTRACKED\fP
The packet is not tracked at all, which happens if you explicitly untrack it
by using \-j CT \-\-notrack in the raw table.
.TP
\fBSNAT\fP
A virtual state, matching if the original source address differs from the reply
destination.
.TP
\fBDNAT\fP
A virtual state, matching if the original destination differs from the reply
source.
.PP
Statuses for \fB\-\-ctstatus\fP:
.TP
\fBNONE\fP
None of the below.
.TP
\fBEXPECTED\fP
This is an expected connection (i.e. a conntrack helper set it up).
.TP
\fBSEEN_REPLY\fP
Conntrack has seen packets in both directions.
.TP
\fBASSURED\fP
Conntrack entry should never be early-expired.
.TP
\fBCONFIRMED\fP
Connection is confirmed: originating packet has left box.