#!/bin/bash
sysctl -w net.ipv4.ip_forward=1
iptables -F -t filter
iptables -F  nat

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

iptables -A INPUT -p tcp --dport 22 -j ACCEPT
iptables -A OUTPUT -p tcp --sport 22 -j ACCEPT

iptables -A OUTPUT -p tcp --dport 80 -j ACCEPT
iptables -A INPUT -p tcp --sport 80 -j ACCEPT

iptables -A OUTPUT -p udp --dport 53 -j ACCEPT
iptables -A INPUT -p udp --sport 53 -j ACCEPT

iptables -A OUTPUT -p tcp -d 10.121.38.1 --dport 8080 -j ACCEPT
iptables -A INPUT -p tcp -d 10.121.38.1 --sport 8080 -j ACCEPT

iptables -t nat -A POSTROUTING -o enp0s3 -j MASQUERADE
iptables -A FORWARD -o enp0s3 -j ACCEPT
iptables -A FORWARD -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT