#!/bin/sh # # firewall-standalone This script sets up firewall rules for a standalone # machine # # Copyright (C) 2000 Roaring Penguin Software Inc. This software may # be distributed under the terms of the GNU General Public License, version # 2 or any later version. # Interface to Internet EXTIF=ppp+ ANY=0.0.0.0/0 ipchains -P input ACCEPT ipchains -P output ACCEPT ipchains -P forward DENY ipchains -F forward ipchains -F input ipchains -F output # Deny TCP and UDP packets to privileged ports ipchains -A input -l -i $EXTIF -d $ANY 0:1023 -p udp -j DENY ipchains -A input -l -i $EXTIF -d $ANY 0:1023 -p tcp -j DENY # Deny TCP connection attempts ipchains -A input -l -i $EXTIF -p tcp -y -j DENY # Deny ICMP echo-requests ipchains -A input -l -i $EXTIF -s $ANY echo-request -p icmp -j DENY