This article was previously published under Q306203
With Microsoft Internet Protocol version 6 (IPv6) installed and Internet Connection Firewall (ICF) or Basic Firewall enabled, the firewall filters Internet Protocol version 4 (IPv4) traffic, but the basic firewall and the ICF do not block or filter IPv6 traffic.
Note ICF is available on Microsoft Windows XP and Microsoft Windows Server 2003, Standard Edition and Windows Server 2003, Enterprise Edition. Basic Firewall is a component of Routing and Remote Access that you can enable for any public interface on a computer that is running Routing and Remote Access and is a member of the Windows Server 2003 family.
ICF in Windows XP and Windows XP Service Pack 1 (SP1), and ICF and Basic Firewall in Windows Server 2003, filter IPv4 traffic only.
To resolve this problem, obtain and install the Advanced Networking Pack for Windows XP. For additional information about the Advanced Networking Pack for Windows XP, click the following article number to view the article in the Microsoft Knowledge Base:
817778 Overview of the Advanced Networking Pack for Windows XP
To work around this behavior, obtain firewall software that can filter and block IPv6 traffic.
For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
320855 Description of the Windows XP Internet Connection Firewall
For additional information on IPv6, see the following Microsoft Web site: