Linux IP Masquerade HOWTO - The Linux Documentation Project

# Source function library.
. /etc/rc.d/init.d/functions
# Check that networking is up.
[ "XXXX${NETWORKING}" = "XXXXno" ] && exit 0
[ −x /sbin/ifconfig ] || exit 0
# The location of various iptables and other shell programs
#
# If your Linux distribution came with a copy of iptables, most
# likely it is located in /sbin. If you manually compiled
# iptables, the default location is in /usr/local/sbin
#
# ** Please use the "whereis iptables" command to figure out
# ** where your copy is and change the path below to reflect
# ** your setup
#
IPTABLES=/usr/local/sbin/iptables
# See how we were called.
case "$1" in
start)
/etc/rc.d/rc.firewall−iptables
;;
stop)
echo −e "\nFlushing firewall and setting default policies to DROP\n"
$IPTABLES −P INPUT DROP
$IPTABLES −F INPUT
$IPTABLES −P OUTPUT DROP
$IPTABLES −F OUTPUT
$IPTABLES −P FORWARD DROP
$IPTABLES −F FORWARD
$IPTABLES −F −t nat
# Delete all User−specified chains
$IPTABLES −X
#
# Reset all IPTABLES counters
$IPTABLES −Z
;;
restart)
$0 stop
$0 start
;;
status)
$IPTABLES −L
;;
mlist)
cat /proc/net/ip_conntrack
;;
*)
Linux IP Masquerade HOWTO
echo "Usage: firewall−iptables {start|stop|status|mlist}"
Chapter 3. Setting Up IP Masquerade 43