#!/bin/sh

IPTABLES=/sbin/iptables
MODPROBE=/sbin/modprobe
INT_NET=10.168.1.0/24

### flush existing rules and set chain policy setting to DROP

echo "[+] Flushing existing iptables rules..."
$IPTABLES -F
$IPTABLES -F -t nat
$IPTABLES -X
$IPTABLES -P INPUT DROP
$IPTABLES -P OUTPUT DROP
$IPTABLES -P FORWARD DROP

### load connection-tracking modules

$MODPROBE ip_conntrack
$MODPROBE iptable_nat
$MODPROBE ip_conntrack_ftp
$MODPROBE ip_nat_ftp

###### INPUT chain ######

echo "[+] Setting up INPUT chain..."

### state tracking rules
$IPTABLES -A INPUT -m state --state INVALID -j LOG --log-prefix "DROP INVALID " --log-ip-options --log-tcp-options
$IPTABLES -A INPUT -m state --state INVALID -j DROP
#$IPTABLES -A INPUT -i eth0 -s ! $INT_NET --syn -m state --state NEW -j LOG --log-prefix "INTRUSION"
#$IPTABLES -A INPUT -i eth0 -s ! $INT_NET --syn -m state --state NEW -j DROP
$IPTABLES -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

### anti-spoofing rules

$IPTABLES -A INPUT -i eth1 -s ! $INT_NET -j LOG --log-prefix "SPOOFED PKT "
$IPTABLES -A INPUT -i eth1 -s ! $INT_NET -j DROP

### ACCEPT rules

$IPTABLES -A INPUT -i eth1 -p tcp -s $INT_NET --dport 8080 -j ACCEPT # 22 --syn -m state --state NEW -j ACCEPT
$IPTABLES -A INPUT -i eth1 -p tcp -s $INT_NET --dport 80 -j ACCEPT

$IPTABLES -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
### default INPUT LOG rule
$IPTABLES -A INPUT -i ! lo -j LOG --log-prefix "DROP " --log-ip-options --log-tcp-options

###### OUTPUT chain ######
echo "[+] Setting up OUTPUT chain..."
### state tracking rules

$IPTABLES -A OUTPUT -m state --state INVALID -j LOG --log-prefix "DROP INVALID " --log-ip-options --log-tcp-options
$IPTABLES -A OUTPUT -m state --state INVALID -j DROP
$IPTABLES -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

### ACCEPT rules for allowing connections out

$IPTABLES -A OUTPUT -p tcp --dport 21 --syn -m state --state NEW -j ACCEPT
$IPTABLES -A OUTPUT -p tcp --dport 22 --syn -m state --state NEW -j ACCEPT
$IPTABLES -A OUTPUT -p tcp --dport 25 --syn -m state --state NEW -j ACCEPT
$IPTABLES -A OUTPUT -p tcp --dport 43 --syn -m state --state NEW -j ACCEPT
$IPTABLES -A OUTPUT -p tcp --dport 80 --syn -m state --state NEW -j ACCEPT
$IPTABLES -A OUTPUT -p tcp --dport 443 --syn -m state --state NEW -j ACCEPT
$IPTABLES -A OUTPUT -p tcp --dport 4321 --syn -m state --state NEW -j ACCEPT
$IPTABLES -A OUTPUT -p udp --dport 53 -m state --state NEW -j ACCEPT
$IPTABLES -A OUTPUT -p icmp --icmp-type echo-request -j ACCEPT

### default OUTPUT LOG rule

$IPTABLES -A OUTPUT -o ! lo -j LOG --log-prefix "DROP " --log-ip-options --log-tcp-options

service iptables save