Ejemplo de iptables I

#!/bin/sh

# Firewall by XiuX

echo ” Activando Firewall by XiuX”

iptables -F

iptables -X

iptables -Z

iptables -t nat -F

echo ” Haciendo cambios…”

iptables -P INPUT ACCEPT

iptables -P OUTPUT ACCEPT

iptables -P FORWARD ACCEPT

iptables -t nat -P PREROUTING ACCEPT

iptables -t nat -P POSTROUTING ACCEPT

echo ” Aplicadas politicas por defecto”

echo ” Filtrando conexiones…”

iptables -A INPUT -i lo -j ACCEPT

iptables -A INPUT -s 82.130.190.216 -j ACCEPT

iptables -A INPUT -p tcp -i eth0 -m state –state NEW,ESTABLISHED,RELATED –dport 22 -j ACCEPT

iptables -A INPUT -p tcp -i eth0 -m state –state NEW,ESTABLISHED,RELATED –dport 10000 -j ACCEPT

iptables -A INPUT -p tcp -i eth0 -m state –state NEW,ESTABLISHED,RELATED –dport 6667 -j ACCEPT

iptables -A INPUT -p tcp -i eth0 -m state –state NEW,ESTABLISHED,RELATED –dport 31337 -j ACCEPT

iptables -A INPUT -p tcp -i eth0 -m state –state NEW,ESTABLISHED,RELATED –dport 80 -j ACCEPT

iptables -A INPUT -p tcp -i eth0 -m state –state NET,ESTABLISHED,RELATED –dport 21 -j ACCEPT

echo ” Exceptuando puertos SSH,Webmin,psyBNC,Web e IRCd”

iptables -A OUTPUT -p tcp -m state –state NEW,ESTABLISHED,RELATED –dport 80 -j ACCEPT

iptables -A OUTPUT -p tcp -m state –state NEW,ESTABLISHED,RELATED –dport 6667 -j ACCEPT

iptables -A OUTPUT -p tcp -m state –state NEW,ESTABLISHED,RELATED –dport 25 -j ACCEPT

iptables -A OUTPUT -p tcp -m state –state NEW,ESTABLISHED,RELATED –dport 21 -j ACCEPT

iptables -A INPUT -p all -i eth0 -m state –state NEW,INVALID -j DROP

echo ” Bloqueados TODOS los demas puertos”

echo ” Ignoramos los ICMP Packets”

iptables -A INPUT -i eth0 -p icmp –icmp-type 8 -j DROP

iptables -A INPUT -i eth0 -p icmp –icmp-type 7 -j DROP

iptables -A INPUT -i eth0 -p icmp –icmp-type 6 -j DROP

iptables -A INPUT -i eth0 -p icmp –icmp-type 5 -j DROP

iptables -A INPUT -i eth0 -p icmp –icmp-type 4 -j DROP

iptables -A INPUT -i eth0 -p icmp –icmp-type 3 -j DROP

iptables -A INPUT -i eth0 -p icmp –icmp-type 2 -j DROP

iptables -A INPUT -i eth0 -p icmp –icmp-type 1 -j DROP

iptables -A INPUT -i eth0 -p icmp –icmp-type 0 -j DROP

iptables -A FORWARD -i eth0 -p icmp –icmp-type 8 -j DROP

iptables -A FORWARD -i eth0 -p icmp –icmp-type 7 -j DROP

iptables -A FORWARD -i eth0 -p icmp –icmp-type 6 -j DROP

iptables -A FORWARD -i eth0 -p icmp –icmp-type 5 -j DROP

iptables -A FORWARD -i eth0 -p icmp –icmp-type 4 -j DROP

iptables -A FORWARD -i eth0 -p icmp –icmp-type 3 -j DROP

iptables -A FORWARD -i eth0 -p icmp –icmp-type 2 -j DROP

iptables -A FORWARD -i eth0 -p icmp –icmp-type 1 -j DROP

iptables -A FORWARD -i eth0 -p icmp –icmp-type 0 -j DROP

iptables -A INPUT -i eth0 -p udp -j DROP

iptables -A FORWARD -i eth0 -p udp -j DROP

echo ” Configuramos argumento “FORWARD”

echo 1 > /proc/sys/net/ipv4/ip_forward

echo ” Activando Firewall”

iptables -L -n