iptables

#!/bin/bash

IPTABLES="/sbin/iptables"

# Interface Internet
INET="ppp0"

# Limpando as regras em memória
$IPTABLES -F -t filter
$IPTABLES -F -t mangle
$IPTABLES -F -t nat
$IPTABLES -X -t filter
$IPTABLES -X -t mangle
$IPTABLES -X -t nat
$IPTABLES -Z -t filter
$IPTABLES -Z -t mangle
$IPTABLES -Z -t nat

# Mudando as políticas para DROP
$IPTABLES -t filter -P INPUT DROP
$IPTABLES -t filter -P OUTPUT DROP
$IPTABLES -t filter -P FORWARD DROP

# Manter Conexões Estabelecidas
$IPTABLES -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

# DNS
$IPTABLES -A OUTPUT -o $INET -p tcp -m multiport --dports 53,5353 -j ACCEPT
$IPTABLES -A OUTPUT -o $INET -p udp -m multiport --dports 53,5353 -j ACCEPT

# HTTP e HTTPS
$IPTABLES -A OUTPUT -o $INET -p tcp -m multiport --dports 80,8080,8081,443 -j ACCEPT

# MSN
$IPTABLES -A OUTPUT -o $INET -p tcp -m multiport --dports 1863,7001 -j ACCEPT
$IPTABLES -A OUTPUT -o $INET -p udp --dport 7001 -j ACCEPT

# Gtalk/Jabber
$IPTABLES -A OUTPUT -o $INET -p tcp --dport 5222 -j ACCEPT

# Ping
$IPTABLES -A OUTPUT -o $INET -p icmp --icmp-type 8 -j ACCEPT