#!/bin/sh # # firewall-standalone This script sets up firewall rules for a standalone # machine # # Copyright (C) 2005 Roaring Penguin Software Inc. This software may # be distributed under the terms of the GNU General Public License, version # 2 or any later version. # LIC: GPL # Interface to Internet EXTIF=ppp+ iptables -P INPUT ACCEPT iptables -P OUTPUT ACCEPT iptables -P FORWARD DROP iptables -F FORWARD iptables -F INPUT iptables -F OUTPUT # Deny TCP and UDP packets to privileged ports iptables -A INPUT -p udp -i $EXTIF --dport 0:1023 -j LOG iptables -A INPUT -p tcp -i $EXTIF --dport 0:1023 -j LOG iptables -A INPUT -p udp -i $EXTIF --dport 0:1023 -j DROP iptables -A INPUT -p tcp -i $EXTIF --dport 0:1023 -j DROP # Deny TCP connection attempts iptables -A INPUT -i $EXTIF -p tcp --syn -j LOG iptables -A INPUT -i $EXTIF -p tcp --syn -j DROP # Deny ICMP echo-requests iptables -A INPUT -i $EXTIF -p icmp --icmp-type echo-request -j DROP