Iptables -F INPUT

Iptables -F OUTPUT

Iptables -F FORWARD

Iptables -A INPUT -p tcp --dport 22 -m state --state NEW -j ACCEPT

Iptables -P INPUT DROP

Iptables -P OUTPUT DROP

Iptables -P FORWARD DROP

Iptables -A INPUT -p icmp -j ACCEPT

Iptables -A OUTPUT -p icmp -j ACCEPT

Iptables -A INPUT -p tcp -m state --state ESTABLISHED,RELATED -j ACCEPT

Iptables -A OUTPUT -p tcp -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT

Iptables -A INPUT -p udp -m state --state ESTABLISHED,RELATED -j ACCEPT