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The "libnetfilter_cttimeout" project

What is libnetfilter_cttimeout?

libnetfilter_cttimeout is the userspace library that provides the programming interface to the fine-grain connection tracking timeout infrastructure. With this library, you can create, update and delete timeout policies that can be attached to traffic flows. This library is used by conntrack-tools.


libnetfilter_cttimeout requires libmnl and a kernel that includes the nfnetlink_cttimeout subsystem (i.e. 3.4 or later).

Main Features

  • creating timeout policy objects
  • retrieving timeout policy objects
  • deleting timeout policy objects

For the nfnetlink_cttimeout subsystem.


You can check the library documentation generated in doxygen format.

Git Tree

The current development version of libnetfilter_cttimeout can be accessed at


libnfnetlink_cttimeout has been written by Pablo Neira Ayuso.

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