Download ipt_pkd 1.4

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. This version adds support for libxtables, iptables 1.4.3.2, and Linux kernel 2.6.29. A port config option was added on the Python knock, so you don't have to have a bunch of UDP ports open on a firewall to pass a knock through to an internal client.