i want to make my first firewall
)
what's wrong becouse when i run it, the internet connection goes down (sorry for my english)
#!/bin/sh
modprobe ip_tables
modprobe ip_conntrack
modprobe ip_conntrack_ftp
modprobe ip_nat_ftp
modprobe ip_conntrack_irc
modprobe ip_nat_irc
iptables=/usr/sbin/iptables
$iptables -P INPUT DROP
$iptables -P OUTPUT DROP
$iptables -P FORWARD DROP
$iptables -F INPUT
$iptables -F OUTPUT
$iptables -F FORWARD
$iptables -A INPUT -i lo -j ACCEPT
$iptables -A OUTPUT -o lo -j ACCEPT
#$iptables -A INPUT -i eth1 -s 192.168.0.1/24 -j ACCEPT
$iptables -A INPUT -p TCP -m state --state ESTABLISHED,RELATED -j ACCEPT
$iptables -A INPUT -p TCP -i eth0 -s 0/0 --destination-port 22 -j ACCEPT
$iptables -A INPUT -p TCP -i eth0 -s 0/0 --destination-port 80 -j ACCEPT
$iptables -A INPUT -p TCP -i eth0 -s 0/0 --destination-port 21 -j ACCEPT
$iptables -A INPUT -p TCP -i eth0 -s 0/0 --destination-port 53 -j ACCEPT
$iptables -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
$iptables -A INPUT -p TCP ! --syn -m state --state NEW -j LOG --log-prefix "Possbile syn scan"
$iptables -A INPUT -p TCP ! --syn -m state --state NEW -j DROP
thanks