I am working on a wireless security project, which involves bridging, routing, and packet filtering (but not NAT). As I was looking at my current default iptables rule set, I noticed that it could use some cleaning up.

This firewall script is designed for stand alone hosts that provide some services.

The script takes a single argument for the interface to run on, but will default to eth0 if you do nothing.


#!/bin/sh
# firewall-up.sh
#v3.07

if [ "$#" = "0" ]; then
EXT_INT="eth0"
exit 1
else
EXT_INT=$1
fi

PATH=/bin:/sbin:/usr/local/sbin/:/usr/sbin