Securing-Optimizing-RH-Linux-1_2_131
Comments and suggestions concerning this book should be mailed to gmourani@videotron.ca
© Copyright 1999-2000 Gerhard Mourani and Open Network Architecture ®
131
If you don’t want some services listed in the firewall rules files for the Gateway Server that I make
ON by default, comment them out with a "#" at the beginning of the line. If you want some other
services that I commented out with a "#", then remove the "#" at the beginning of their lines. If you
are configured Masquerading on your server, uncomment the modules necessary to masquerade
their respective services that you need like ip_masq_irc.o, ip_masq_raudio.o, etc.
Create the firewall script file (touch /etc/rc.d/init.d/firewall) on your Gateway Server and add:
#!/bin/sh
#
# ----------------------------------------------------------------------------
# Last modified by Gerhard Mourani: 02-01-2000
# ----------------------------------------------------------------------------
# Copyright (C) 1997, 1998, 1999 Robert L. Ziegler
#
# Permission to use, copy, modify, and distribute this software and its
# documentation for educational, research, private and non-profit purposes,
# without fee, and without a written agreement is hereby granted.
# This software is provided as an example and basis for individual firewall
# development. This software is provided without warranty.
#
# Any material furnished by Robert L. Ziegler is furnished on an
# "as is" basis. He makes no warranties of any kind, either expressed
# or implied as to any matter including, but not limited to, warranty
# of fitness for a particular purpose, exclusivity or results obtained
# from use of the material.
# ----------------------------------------------------------------------------
#
# Invoked from /etc/rc.d/init.d/firewall.
# chkconfig: - 60 95
# description: Starts and stops the IPCHAINS Firewall \
# used to provide Firewall network services.
# Source function library.
. /etc/rc.d/init.d/functions
# Source networking configuration.
. /etc/sysconfig/network
# Check that networking is up.
if [ ${NETWORKING} = "no" ]
then
exit 0
fi
[ -f /sbin/ipchains ] || exit 0
# See how we were called.
case "$1" in
start)
echo -n "Starting Firewalling Services: "
# Some definitions for easy maintenance.
# ----------------------------------------------------------------------------
# EDIT THESE TO SUIT YOUR SYSTEM AND ISP.
EXTERNAL_INTERFACE="eth0"
# whichever you use
LOCAL_INTERFACE_1="eth1"
# whichever you use
LOOPBACK_INTERFACE="lo"