#!/bin/bash										  
#poormans firewall script
INT=eth0

/sbin/modprobe ip_tables
# ensure that all necessary modules are loaded into the kernel
# what do they do?  
# ip_tables is so that the iptables tool can adjust certain
# kernel parameters

/sbin/iptables -P INPUT ACCEPT
/sbin/iptables -F INPUT

# set policy for the INPUT chain to be accept, and then 
# flush all rules

/sbin/iptables -P OUTPUT ACCEPT
/sbin/iptables -F OUTPUT      

# set OUTPUT to be accept, and flush all rules

/sbin/iptables -P FORWARD DROP
/sbin/iptables -F FORWARD    

# set FORWARD chain to drop everything, unless told differently
# then flush all rules

# Voila.  We've set some rules, but we aren't doing anything useful
# at all.  Why?  We're allowing ALL traffic to be output, and all
# traffic to be input.  That's pretty poor filtering in anyone's book.