BASH - ipTables firewall

FW=/sbin/iptables
echo 0 > /proc/sys/net/ipv4/ip_forward
OFF_IP=87.72.XXX.XXX     # Firewalls exterior IP.
INET_IF=eth0 # Internet interface
LAN_IF=eth1  # LAN interface

echo "Remove all prior rules including NAT"
$FW -F ; $FW -X ; $FW -Z ; $FW -F -t nat
echo "Set policy"
$FW -P INPUT DROP    # Luk alt input
$FW -P FORWARD DROP  #
$FW -P OUTPUT ACCEPT     # Accepter alt output

echo "Tilladt indefra oprettede forbindelser adgang udefra"
$FW -A INPUT -j ACCEPT -m state --state ESTABLISHED,RELATED
$FW -A FORWARD -j ACCEPT -m state --state ESTABLISHED,RELATED
$FW -t nat -A POSTROUTING -o $INET_IF -j SNAT --to-source $OFF_IP

echo "INPUT rules"
# Accept trafic from LAN
$FW -A INPUT -i lo -j ACCEPT # Server can connect locally
$FW -A INPUT -i $LAN_IF -j ACCEPT    # Accepter alt trafik fra LAN

#echo "Allow ICMP packages (Ping)"
#$FW -A FORWARD -p icmp --icmp-type echo-request -j ACCEPT
#$FW -A FORWARD -p icmp --icmp-type echo-reply -j ACCEPT
#$FW -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
#$FW -A INPUT -p icmp --icmp-type echo-reply -j ACCEPT

# Tillad trafik til serveren
$FW -A INPUT -i $INET_IF -j ACCEPT -p tcp --dport 20 # FTP-data
$FW -A INPUT -i $INET_IF -j ACCEPT -p tcp --dport 21 # FTP
$FW -A INPUT -i $INET_IF -j ACCEPT -p udp --dport 21 # FTP
$FW -A INPUT -i $INET_IF -j ACCEPT -p tcp --dport 25 # SMTP
$FW -A INPUT -i $INET_IF -j ACCEPT -p tcp --dport 47     # SSH
$FW -A INPUT -i $INET_IF -j ACCEPT -p udp --dport 47 # SSH
$FW -A INPUT -i $INET_IF -j ACCEPT -p tcp --dport 80 # Apache
$FW -A INPUT -i $INET_IF -j ACCEPT -p udp --dport 80 # Apache
$FW -A INPUT -i $INET_IF -j ACCEPT -p tcp --dport 110 # POP3
$FW -A INPUT -i $INET_IF -j ACCEPT -p udp --dport 110 # POP3
$FW -A INPUT -i $INET_IF -j ACCEPT -p tcp --dport 443    # SSL
$FW -A INPUT -i $INET_IF -j ACCEPT -p udp --dport 443 # SSL

echo 1 > /proc/sys/net/ipv4/ip_forward