nfct man page

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 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.

Subsys

By the time this manpage has been written, the supported subsystem are timeout

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>.

Info

Feb 29, 2012