Flaw: ICMP Router Discovery Protocol (IRDP) comes enabled by default on DHCP clients that are running Microsoft Windows95 (w/winsock2), Windows95b, Windows98, Windows98se, and Windows2000 machines. ZDNET article here Headline excerpt: Hackers may be snooping on you Article Excerpt: Companies and users of broadband modems beware: Malicious hackers may be "listening" in on your computer's conversation across the Internet. Full Detail Advisory: IRDP Default Route Assignment Excerpt: By spoofing IRDP Router Advertisements, an attacker can remotely add default route entries on a remote system. Fix for above flaw (FYI I have not tried it yet): DHCP fix provided by Analogx Also see Full Detail Advisory there are 2 suggested fixes there (or view next post). The registry key fix is probably what is being done by Analogx fix. I ran across the DHCP fix at Analogx and followed the links to the Advisory to get more info. Conclusion: If you own one of the above mentioned OS and are using broadband modem, you may want to look further into this flaw.