What is Packet Filter: A packet filter is a piece of software which looks at the header of packets as they pass through, and decides the fate of the entire packet. It might decide to DROP the packet (i.e., discard the packet as if it had never received it), ACCEPT the packet (i.e., let the packet go through), or something more complicated.

Firewall for home users: Its a simple firewall script for home users to protect there system from "dirty" Internet.