#!/bin/sh
#

INET_IFACE="eth1"

DHCP="yes"
DHCP_SERVER=""

PPPOE_PMTU="no"

LAN_IP="192.168.100.1"
LAN_IP_RANGE="192.168.100.0/24"
LAN_IFACE="eth0"

LO_IFACE="lo"
LO_IP="127.0.0.1"

IPTABLES="/sbin/iptables"


$IPTABLES -P INPUT DROP
$IPTABLES -P OUTPUT DROP
$IPTABLES -P FORWARD DROP

$IPTABLES -N allowed
$IPTABLES -N allaccess
$IPTABLES -N tcp_packets
$IPTABLES -N udp_packets
$IPTABLES -N icmp_packets

$IPTABLES -A bad_tcp_packets -p tcp --tcp-flags SYN,ACK SYN,ACK \
-m state --state NEW -j REJECT --reject-with tcp-reset
$IPTABLES -A bad_tcp_packets -p tcp ! --syn -m state --state NEW -j LOG \
--log-prefix "New not syn:"
$IPTABLES -A bad_tcp_packets -p tcp ! --syn -m state --state NEW -j DROP


$IPTABLES -A allowed -p tcp --syn -j LOG \
--log-prefix "Input packet"
$IPTABLES -A allowed -p TCP --syn -j ACCEPT
$IPTABLES -A allowed -p TCP -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A allowed -p TCP -j DROP


$IPTABLES -A allaccess -p TCP -j LOG --log-prefix "Port Forwarding: "
$IPTABLES -A allaccess -p TCP -j ACCEPT



#-ftp ports
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 20 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 21 -j allowed
#-ssh ports
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 22 -j allowed
#-http ports
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 80 -j allowed
#-Email ports
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 25 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --source-port 25 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 110 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 143 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 113 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 993 -j allowed
#-squid ports
#$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 3128 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 443 -j allowed
#-MSN Messenger ports
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 6891:6901 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 1863 -j allowed
#-Kazaa ports
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 1214 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 2608 -j allowed
#-Interent Switchboard ports
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 7750:7751 -j allaccess
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 3306 -j allowed


$IPTABLES -A udp_packets -p UDP -s 0/0 --source-port 53 -j ACCEPT
if [ $DHCP == "yes" ] ; then
 $IPTABLES -A udp_packets -p UDP -s 0/0 --sport 67 \
 --dport 68 -j ACCEPT
fi

$IPTABLES -A udp_packets -p UDP -s 0/0 --source-port 53 -j ACCEPT
$IPTABLES -A udp_packets -p UDP -s 0/0 --source-port 123 -j ACCEPT
$IPTABLES -A udp_packets -p UDP -s 0/0 --source-port 2074 -j ACCEPT
$IPTABLES -A udp_packets -p UDP -s 0/0 --source-port 4000 -j ACCEPT
$IPTABLES -A udp_packets -p UDP -s 0/0 --source-port 1863 -j ACCEPT
$IPTABLES -A udp_packets -p UDP -s 0/0 --source-port 6901 -j ACCEPT


#$IPTABLES -A udp_packets -p UDP -i $INET_IFACE -d 255.255.255.255 \
#--destination-port 67:68 -j DROP


$IPTABLES -A icmp_packets -p ICMP -s 0/0 --icmp-type 8 -j ACCEPT
$IPTABLES -A icmp_packets -p ICMP -s 0/0 --icmp-type 11 -j ACCEPT

$IPTABLES -A INPUT -p tcp -j bad_tcp_packets

$IPTABLES -A INPUT -p ALL -i $LAN_IFACE -s $LAN_IP_RANGE -j ACCEPT
$IPTABLES -A INPUT -p ALL -i $LO_IFACE -j ACCEPT


$IPTABLES -A INPUT -p UDP -i $LAN_IFACE --dport 67 --sport 68 -j ACCEPT

$IPTABLES -A INPUT -p ALL -i $INET_IFACE -m state --state ESTABLISHED,RELATED \
-j ACCEPT
$IPTABLES -A INPUT -p TCP -i $INET_IFACE -j tcp_packets
$IPTABLES -A INPUT -p UDP -i $INET_IFACE -j udp_packets
$IPTABLES -A INPUT -p ICMP -i $INET_IFACE -j icmp_packets


$IPTABLES -A INPUT -m limit --limit 3/minute --limit-burst 3 -j LOG \
--log-level DEBUG --log-prefix "IPT INPUT packet died: "


$IPTABLES -A FORWARD -i $LAN_IFACE -j ACCEPT
$IPTABLES -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT



$IPTABLES -A FORWARD -p tcp -i $INET_IFACE --dport 7750:7751 -j ACCEPT
$IPTABLES -A FORWARD -p udp -i $INET_IFACE --dport 7750:7751 -j ACCEPT
$IPTABLES -A FORWARD -p tcp --dport 4662 -j ACCEPT 


$IPTABLES -A FORWARD -m limit --limit 3/minute --limit-burst 3 -j LOG \
--log-level DEBUG --log-prefix "IPT FORWARD packet died: "

$IPTABLES -A OUTPUT -p tcp -j bad_tcp_packets

$IPTABLES -A OUTPUT -p ALL -s $LO_IP -j ACCEPT
$IPTABLES -A OUTPUT -p ALL -s $LAN_IP -j ACCEPT
$IPTABLES -A OUTPUT -p ALL -o $INET_IFACE -j ACCEPT


$IPTABLES -A OUTPUT -m limit --limit 3/minute --limit-burst 3 -j LOG \
--log-level DEBUG --log-prefix "IPT OUTPUT packet died: "

$IPTABLES -t nat -A PREROUTING -i $INET_IFACE -p tcp --dport 7750:7751 -j DNAT --to 192.168.100.12
$IPTABLES -t nat -A PREROUTING -i $INET_IFACE -p udp --dport 7750:7751 -j DNAT --to 192.168.100.12
$IPTABLES -t nat -A PREROUTING -i $INET_IFACE -p tcp --dport 4662 -j DNAT --to 192.168.100.11

if [ $PPPOE_PMTU == "yes" ] ; then
 $IPTABLES -t nat -A POSTROUTING -p tcp --tcp-flags SYN,RST SYN \
 -j TCPMSS --clamp-mss-to-pmtu
fi
$IPTABLES -t nat -A POSTROUTING -o $INET_IFACE -j MASQUERADE