NFCT(8)

NAME
nfct - command line tool to configure with the connection tracking system

SYNOPSIS
nfct command subsystem [parameters]

DESCRIPTION
nfct is the command line tool that allows you to configure the Connection Tracking System.

COMMANDS

list
    List the existing objects.

add Add new object.

delete
    Delete an object.

get Get an existing object.

flush
    Flush the accounting object table.

disable
    This command is for the helper subsystem. It allows you to disable enqueueing packets to userspace for helper inspection.

default-set
    This command is for the timeout subsystem. It allows you to set default protocol timeouts.

default-get
    This command is for the timeout subsystem. It allows you to get the default protocol timeouts.

SUBSYS
By the time this manpage has been written, the supported subsystems are timeout and helper.

timeout
    The timeout subsystem allows you to define fine-grain timeout policies.

helper
    The helper subsystem allows you to configure userspace helpers.

version
    Displays the version information.

help
    Displays the help message.

EXAMPLE

nfct add timeout test-tcp inet tcp established 100 close 10 close_wait 10

This creates a timeout policy for tcp using 100 seconds for the ESTABLISHED state, 10 seconds for CLOSE state and 10 seconds for the CLOSE_WAIT state.

Then, you can attach the timeout policy with the iptables CT target:

iptables -I PREROUTING -t raw -p tcp -j CT --timeout test-tcp

iptables -I OUTPUT -t raw -p tcp -j CT --timeout test-tcp

You can test that the timeout policy with:

conntrack -E -p tcp

It should display:

[UPDATE] tcp 6 100 ESTABLISHED src=192.168.39.100 dst=57.126.1.20 sport=56463 dport=80 src=57.126.1.20 dst=192.168.39.100 sport=80 dport=56463 [ASSURED]

SEE ALSO
iptables(8),conntrack(8)

BUGS
Please, report them to netfilter-devel@vger.kernel.org or file a bug in Netfilter's bugzilla (https://bugzilla.netfilter.org).

AUTHORS
Pablo Neira Ayuso wrote and maintains the nfct tool.

Man page written by Pablo Neira Ayuso <pablo@netfilter.org>.