#!/bin/bash
#@Guilherme2041

#Apaga todas as regras
iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -t mangle -F
iptables -t mangle -X

#Bloquear tudo
iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -P FORWARD DROP

#Permitir conexões pre-estabelecidas
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -t filter -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

#Permitir DNS
iptables -A OUTPUT -p udp --dport 53 -m state --state NEW -j ACCEPT
iptables -A INPUT -p udp --dport 53 -m state --state NEW -j ACCEPT

#Permitir SSH
iptables -A INPUT -p tcp --dport 22 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 22 -j ACCEPT

#Permitir HTTP/HTTPS
iptables -A INPUT -p tcp --dport 443 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 443 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 80 -j ACCEPT

#Bloquear PING
iptables -A INPUT -p icmp --icmp-type echo-request -j DROP

echo Aplicado.