How to protect registered IP addresses

Princeton has a piece of code that ARP bombs unregistered hosts. IPs that
are broken get sent an ARP packet with the same IP and an ethernet
address of 00:00:00:de:ad or something. This is usually enough to disable
Windows 95 boxes (since they do a RARP call when they boot up to check
for duplicates) and some other OSes too. This provides a quick filter
before actually blocking things at the router level, which is more expensive.

Of course the clueful can easily get around this, but hey.

-Tung-Hui Hu / Arc Four /