Section 8 · System administration
nfct.8
Package: conntrack-tools
NFCT
NAME
SYNOPSIS
DESCRIPTION
COMMANDS
SUBSYS
EXAMPLE
SEE ALSO
BUGS
AUTHORS
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>.