Microsoft Knowledge Base Article - 306203 (Score 1)

This one makes me laugh and cry:

Internet Connection Firewall and Basic Firewall Do Not Block Internet Protocol Version 6 Traffic
CAUSE
ICF in Windows XP and Windows XP Service Pack 1 (SP1), and ICF and Basic Firewall in Windows Server 2003, filter IPv4 traffic only.
WORKAROUND
To work around this behavior, obtain firewall software that can filter and block IPv6 traffic.