[root@scooter]~# iptables -P INPUT DROP
[root@scooter]~# iptables -A INPUT -s 0.0.0.0/255.255.255.255 -j DROP
[root@scooter]~# iptables -L -n
Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination