A server that is running Microsoft Windows Server 2003 may not recognize the new Teredo address format

A server that is running Microsoft Windows Server 2003 may not recognize the new Teredo address format. This format is implemented in the new IPv6 standard.

Service pack information

To resolve this problem, obtain the latest service pack for Windows Server 2003. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Hotfix information

Prerequisites

To apply this hotfix, you must have Windows Server 2003 Service Pack 1 or an x64-based version of Windows Server 2003 installed. For more information about how to obtain Windows Server 2003 Service Pack 1, click the following article number to view the article in the Microsoft Knowledge Base:

Restart requirement

You have to 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, x86-based versions

File name	File version	File size	Date	Time	Platform	SP requirement	Service branch
6to4svc.dll	5.2.3790.2739	99,840	04-Jul-2006	13:23	x86	SP1	SP1QFE
Tcpip6.sys	5.2.3790.2739	223,488	04-Jul-2006	10:02	Not Applicable	SP1	SP1QFE

Windows Server 2003, Itanium-based versions

File name	File version	File size	Date	Time	Platform	SP requirement	Service branch
6to4svc.dll	5.2.3790.2739	362,496	04-Jul-2006	01:12	IA-64	SP1	SP1QFE
Tcpip6.sys	5.2.3790.2739	729,856	04-Jul-2006	01:12	Not Applicable	SP1	SP1QFE
W6to4svc.dll	5.2.3790.2739	99,840	04-Jul-2006	01:12	x86	SP1	WOW

Windows Server 2003, x64-based versions

File name	File version	File size	Date	Time	Platform	SP requirement	Service branch
6to4svc.dll	5.2.3790.2739	124,416	04-Jul-2006	01:10	x64	SP1	SP1QFE
Tcpip6.sys	5.2.3790.2739	358,656	04-Jul-2006	01:10	x64	SP1	SP1QFE
W6to4svc.dll	5.2.3790.2739	99,840	04-Jul-2006	01:10	x86	SP1	WOW

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Windows Server 2003 Service Pack 2.

This hotfix changes the Teredo address prefix from 3ffe:831f::/32 to 2001:0000::/32.

The new Teredo address prefix was introduced as part of the Internet Assigned Numbers Authority (IANA) standardization of the Teredo address format in Request for Comments (RFC) 4380, "Teredo: Tunneling IPv6 over UDP through Network Address Translations (NATs)." Host servers use two kinds of Teredo address prefixes: the old Teredo address prefix of 3ffe:831f::/32 and the new Teredo address prefix of 2001:0000::/32. Host servers that use the old address prefix cannot communicate with host servers that use the new address prefix.

To configure a host server to use the new Teredo address prefix, use one of the following methods:

�	Install the hotfix that is described in this article.
�	Install the IPv6 security update that was released on October 10, 2006.
�	Wait until the next Windows Server 2003 service pack is released. Then, install the service pack.

The new address prefix was deployed with the IPv6 security update as part of a broader IPv6 initiative. For more information about the IPv6 security update, visit the following Microsoft Web site:We strongly recommend users to install the security update on host servers that use IPv6 or Teredo. If the server does not use IPv6, we recommend that you wait for the next service pack.

For more information about Teredo, visit the following Microsoft Web site:For more information about the terms that are used to describe software updates, 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 need 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 Microsoft Windows Server 2003 x64 edition separately, contact Microsoft for technical support.

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