Interfaces that have the TCP/IP version 6 protocol installed in Windows Server 2003 incorrectly send duplicate address detection (DAD) packets when DAD fails

A behavior in the TCP/IP version 6 protocol in Windows Server 2003 does not comply with the Request for Comments (RFC) 4862 specifications. This behavior has caused some vendors to fail the IPv6 Logo certification.

As part of duplicate address detection (DAD), a network interface sends a DAD solicit packet for its link local address. If the network interface receives a response to the solicit packet that indicates that the local address is already being used, DAD fails. Therefore, the network interface should disable all IP operations and silently discard all packets that are sent to that interface. However, when a router advertisement package is sent to this interface to advertise a prefix, the interface sends a DAD packet for global addresses by including this prefix.

Note The IPv6 stack in Windows Server 2003 is not designed to pass the IPv6 Logo certification.

This problem occurs because a check is missing from the TCP/IP version 6 protocol in Windows Server 2003.

This hotfix corrects the noncompliant behavior in the TCP/IP version 6 protocol in Windows Server 2003.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix, you must have Windows Server 2003 Service Pack 1 or Windows Server 2003 Service Pack 2 installed on the computer. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Server 2003 with Service Pack 1, x86-based versions

Windows Server 2003 with Service Pack 2, x86-based versions

Windows Server 2003 with Service Pack 1, Itanium-based versions

Windows Server 2003 with Service Pack 2, Itanium-based versions

Windows Server 2003 with Service Pack 1, x64-based versions

Windows Server 2003 with Service Pack 2, x64-based versions

Windows XP Professional x64 Edition with Service Pack 1

Windows XP Professional x64 Edition with Service Pack 2

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

IPv4 nodes use ARP Request messages and a method that is called "gratuitous ARP" to detect duplicate IP addresses on the IPv4 nodes local links. Similarly, IPv6 nodes use the Neighbor Solicitation message to detect duplicate address use on the IPv6 nodes local links.

With gratuitous ARP, the Source Protocol Address and Target Protocol Address fields in the ARP Request message header are set to the IPv4 address for which duplication is being detected. In IPv6 duplicate address detection, the Target Address field in the Neighbor Solicitation message is set to the IPv6 address for which duplication is being detected.

Duplicate address detection differs from address resolution in the following ways:

• In a Neighbor Solicitation message for duplicate address detection, the Source Address field in the IPv6 header is set to the unspecified address (::). The address that is being queried for duplication cannot be used until it is determined that the address is not already being used.
• In the Neighbor Advertisement reply to a Neighbor Solicitation message for duplicate address detection, the Destination Address in the IPv6 header is set to the link-local scope all-nodes multicast address (FF02::1). Because the sender of the Neighbor Solicitation message for duplicate address detection is not using the desired address, the sender cannot receive unicast Neighbor Advertisement messages. Therefore, the Neighbor Advertisement message is multicast.
• When the node receives the multicast Neighbor Advertisement message that is sent in response to the Neighbor Solicitation message, the node disables the use of the duplicate address on the interface. If the node does not receive a Neighbor Advertisement message that defends the use of the IPv6 address, the node initializes the address on the interface.

The following is a sample network trace that is captured when this problem occurs:For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

Technical support for x64-based versions of Microsoft Windows

If your hardware came with a Microsoft Windows x64 edition already installed, your hardware manufacturer provides technical support and assistance for the Windows x64 edition. In this case, your hardware manufacturer provides support because a Windows x64 edition was included with your hardware. Your hardware manufacturer might have customized the Windows x64 edition installation by using unique components. Unique components might include specific device drivers or might include optional settings to maximize the performance of the hardware. Microsoft will provide reasonable-effort assistance if you must have technical help with a Windows x64 edition. However, you might have to contact your manufacturer directly. Your manufacturer is best qualified to support the software that your manufacturer installed on the hardware. If you purchased a Windows x64 edition such as a Windows Server 2003 x64 edition separately, contact Microsoft for technical support.

For product information about Windows XP Professional x64 Edition, visit the following Microsoft Web site: For product information about x64-based versions of Windows Server 2003, visit the following Microsoft Web site: