#!/bin/bash

iptables -F
iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -P FORWARD DROP

#dns
iptables -A OUTPUT -p udp -o eth0 --dport 53 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A INPUT -p udp -i eth0 --sport 53 -mstate --state ESTABLISHED -j ACCEPT

#ping
iptables -A OUTPUT -p icmp -o eth0 --icmp-type echo-request -j ACCEPT
iptables -A INPUT -p icmp -i eth0 --icmp-type echo-reply -j ACCEPT

#ssh server
iptables -A INPUT -p tcp -i eth0 --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp -o eth0 --sport 22 -m state --state ESTABLISHED -j ACCEPT

#ssh client
iptables -A OUTPUT -p tcp -o eth0 --dport 22 -j ACCEPT
iptables -A INPUT -p tcp -i eth0 --sport 22 -j ACCEPT