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The "conntrack-tools" project

What are the conntrack-tools?

The conntrack-tools are a set of tools targeted at system administrators. They are conntrack, the userspace command line interface, and conntrackd, the userspace daemon. The tool conntrack provides a full featured interface that is intended to replace the old /proc/net/ip_conntrack interface. Using conntrack, you can view and manage the in-kernel connection tracking state table from userspace. On the other hand, conntrackd covers the specific aspects of stateful firewalls to enable highly available scenarios, and can be used as statistics collector as well.

Since 1.2.0, the conntrack-tools includes the nfct command line utility. This utility only supports the nfnetlink_cttimeout by now. In the long run, we expect that it will replace conntrack by providing a syntax similar to nftables.

conntrack-tools homepage

The conntrack-tools have its own homepage.


conntrack-tools requires libnetfilter_conntrack, libnfnetlink, libmnl, libnetfilter_cttimeout and a kernel that features the nf_conntrack_netlink subsystem. For officially released kernels, this means 2.6.14, but we suggest you to use 2.6.18 or later. To support the nfnetlink_cttimeout subsystem, you will have to install 3.4.0 or later. To support the nfnetlink_cthelper subsystem, you require 3.6.0 or later.

Main Features

  • listing the contents of the conntrack table in plain text/XML
  • searching for individual entries in the conntrack table
  • adding new entries to the conntrack table
  • listing entries in the expect table
  • adding new entries to the expect table
  • adding/deleting/updating connection tracking timeout policies

Git Tree

The current development version of conntrack-tools can be accessed at


The conntrack-tools were almost entirely written by Pablo Neira Ayuso.

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