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The "libnetfilter_queue" project

What is libnetfilter_queue?

libnetfilter_queue is a userspace library providing an API to packets that have been queued by the kernel packet filter. It is is part of a system that deprecates the old ip_queue / libipq mechanism.

libnetfilter_queue has been previously known as libnfnetlink_queue.


libnetfilter_queue requires libnfnetlink and a kernel that includes the nfnetlink_queue subsystem (i.e. 2.6.14 or later).

Main Features

  • receiving queued packets from the kernel nfnetlink_queue subsystem
  • issuing verdicts and/or reinjecting altered packets to the kernel nfnetlink_queue subsystem


You can check the library documentation generated in doxygen format.

Git Tree

The current development version of libnetfilter_queue can be accessed at


libnetfilter_queue has been written by Harald Welte.

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