Forum Debian Users Gang

#! /bin/sh
# /etc/init.d/blah
#

# Some things that run always
touch /var/lock/firewall

# Carry out specific functions when asked to by the system
case "$1" in
  start)
    echo "Starting firewall "
    iptables -F
    iptables -t nat -F
    iptables -t mangle -F
    iptables -X

    iptables -A INPUT -i lo -j ACCEPT

    iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

    iptables -P INPUT DROP

    iptables -A INPUT -p TCP --dport 8080 -s 192.168.0.0 -j ACCEPT

    iptables -t nat -A PREROUTING -p tcp --dport 6881:6882 -j DNAT --to-destination 192.168.1.2
    iptables -A FORWARD -s 192.168.1.2 -p tcp --dport 6881 -j ACCEPT
    iptables -A FORWARD -s 192.168.1.2 -p udp --dport 6882 -j ACCEPT
    iptables -t nat -A PREROUTING -p tcp --dport 6883:6884 -j DNAT --to-destination 192.168.2.2
    iptables -A FORWARD -s 192.168.2.2 -p tcp --dport 6883 -j ACCEPT
    iptables -A FORWARD -s 192.168.2.2 -p udp --dport 6884 -j ACCEPT

    iptables --table nat --append POSTROUTING --out-interface ppp0 -j MASQUERADE
    iptables --append FORWARD --in-interface ath0 -j ACCEPT
    iptables --append FORWARD --in-interface eth1 -j ACCEPT

    iptables -A INPUT --source 192.168.1.2 -j ACCEPT
    iptables -A INPUT --source 192.168.1.3 -j ACCEPT
    iptables -A INPUT --source 192.168.1.4 -j ACCEPT
    iptables -A INPUT --source 192.168.1.5 -j ACCEPT
    iptables -A INPUT --source 192.168.1.6 -j ACCEPT
    iptables -A INPUT --source 192.168.1.7 -j ACCEPT
    iptables -A INPUT --source 192.168.2.2 -j ACCEPT
    iptables -A INPUT --source 192.168.2.3 -j ACCEPT

    echo 1 > /proc/sys/net/ipv4/ip_forward
    ;;
  stop)
    echo "Stopping firewall"
    iptables -F
    iptables -t nat -F
    iptables -t mangle -F
    iptables -X

    iptables -P INPUT ACCEPT
    echo 0 > /proc/sys/net/ipv4/ip_forward
    ;;
  *)
    echo "Usage: /etc/init.d/blah {start|stop}"
    exit 1
    ;;
esac

exit 0