# Script de Firewall, Direto no Linux Nativo.
# Limpa as Tabelas do IpTables
  iptables -F INPUT
  iptables -F OUTPUT
# Limpa a Particao NAT
  iptables -F -t nat
# Inicia a Execucao do IpTables
  iptables -X
# Limpa o Roteamento
  iptables -F POSTROUTING -t nat
  iptables -F PREROUTING -t nat
# Configurando o Roteamento
  echo 1 > /proc/sys/net/ipv4/ip_forward
  iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
  iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 1723 -j DNAT --to 10.135.16.2
# Definindo Politicas Basicas
  iptables -P INPUT ACCEPT
  iptables -P OUTPUT ACCEPT
  iptables -P FORWARD ACCEPT
# Ate este ponto e o basico para um servidor de internet funcionar e
# rotear o acesso a internet. Onde 10.135.16.2 é o IP do Servidor na
# placa de rede que se conecta ao resto da rede interna.
# Anti Come-Banda
  # iMesh
    iptables -A FORWARD -d 216.35.208.0/24 -j DROP
  # BearShare
    iptables -A FORWARD -d 216.35.208.0/24 -j DROP
  # ToadNode
    iptables -A FORWARD -p TCP --dport 6346 -j DROP
  # WinMX
    iptables -A FORWARD -d 209.61.186.0/24 -j DROP
    iptables -A FORWARD -d 64.49.201.0/24 -j DROP
  # Napigator
    iptables -A FORWARD -d 209.25.178.0/24 -j DROP
  # Morpheus
    iptables -A FORWARD -d 206.142.53.0/24 -j DROP
    iptables -A FORWARD -p TCP --dport 1214 -j DROP
  # KaZaA
    iptables -A FORWARD -d 213.248.112.0/24 -j DROP
    iptables -A FORWARD -p TCP --dport 1214 -j DROP
  # LimeWire
    iptables -A FORWARD -p TCP --dport 6346 -j DROP
  # Audiogalaxy
    iptables -A FORWARD -d 64.245.58.0/23 -j DROP
  # Travas Extras
    iptables -A FORWARD -p TCP --dport 1900 -j DROP
    iptables -A FORWARD -p UDP --dport 1900 -j DROP
# Fim Anti Come-Banda
# Anti Servicos Perigosos
  # AIM
    iptables -A FORWARD -d 64.245.58.0/24 -j DROP
    iptables -A FORWARD -d 64.12.161.153 -j DROP
  # ICQ
    iptables -A FORWARD -p TCP --dport 5190 -j DROP
    iptables -A FORWARD -d 64.12.161.185 -j DROP
  # MSN
    iptables -A FORWARD -p TCP --dport 1863 -j DROP
    iptables -A FORWARD -d messenger.hotmail.com -j DROP
    iptables -A FORWARD -d 64.4.13.0/24 -j DROP
    iptables -A FORWARD -d 207.46.104.0/24 -j DROP
  # Yahoo Messenger
    iptables -A FORWARD -d 216.136.233.128 -j DROP
    iptables -A FORWARD -d 216.136.233.137 -j DROP
    iptables -A FORWARD -d 216.136.233.138 -j DROP
    iptables -A FORWARD -d 216.136.226.208 -j DROP
  # Telnet
    iptables -A INPUT -p TCP --dport 23 -j DROP
    iptables -A OUTPUT -p TCP --dport 23 -j DROP
    iptables -A FORWARD -p TCP --dport 23 -j DROP    
# Fim Anti Servicos Perigosos
# Boqueio de Acesso a Internet para:
  iptables -A FORWARD -s 10.135.16.80 -j DROP
  iptables -A FORWARD -s 10.135.16.97 -j DROP
  iptables -A FORWARD -s 10.135.16.98 -j DROP
  iptables -A FORWARD -s 10.135.16.199 -j DROP
# FTP
  # Podem fazer FTP
    iptables -A FORWARD -p TCP --dport 20 -s 10.135.16.75 -j ACCEPT
    iptables -A FORWARD -p TCP --dport 21 -s 10.135.16.75 -j ACCEPT
  # O Restante nao pode fazer FTP
    iptables -A FORWARD -p TCP --dport 20 -j DROP
    iptables -A FORWARD -p TCP --dport 21 -j DROP
# Fim FTP