Download ipt_pkd 1.6

ipt_pkd is an iptables extension implementing port knock detection. This project provides 3 parts: the kernel module ipt_pkd, the iptables user space module libipt_pkd.so, and a user space client knock program. For the knock packet, it uses a UDP packet sent to a random port that contains a SHA-256 of a timestamp, small header, random bytes, and a shared key. ipt_pkd checks the time window of the packet and does the SHA-256 to verify the packet. The shared key is never sent.

Update:
This version was updated for Linux 2.6.32 and iptables 1.4.6. A new knock client was added, which is written in C# and works on both Linux and Windows and encrypts configuration data. A pre-built kernel module, an iptables library for vyatta community edition 5, and a small install script for vyatta were added.