When the GUID of a network adapter changes on a client computer that is running Windows Vista, the computer registers an old IP address that was associated with the old GUID.

The client computer also registers new IP addresses that are associated with the new GUID. However, because the client computer registers old IP addresses, another client computer may try to use the old IP address. If the old address is not valid, a connection failure may occur.

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The following files are available for download from the Microsoft Download Center:

Windows VistaWindows Vista for 64-bit systems For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base: Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.

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Hotfix information

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 Vista, 32-bit versions

File name	File version	File size	Date	Time	Platform
Dnsapi.dll	6.0.6000.20492	162,816	06-Dec-2006	06:30	x86
Dnscacheugc.exe	6.0.6000.20492	24,576	06-Dec-2006	04:06	x86
Dnsrslvr.dll	6.0.6000.20492	84,480	06-Dec-2006	06:30	x86
Update.mum	Not Applicable	1,995	06-Dec-2006	21:09	Not Applicable
X86_microsoft-windows-dns-client.d_31bf3856ad364e35_6.0.6000.20492_none_a26aac3bc621f520.manifest	Not Applicable	697	06-Dec-2006	21:09	Not Applicable
X86_microsoft-windows-dns-client_31bf3856ad364e35_6.0.6000.20492_none_e02686989e97a8f6.manifest	Not Applicable	29,455	06-Dec-2006	21:10	Not Applicable

Windows Vista, 64-bit versions

File name	File version	File size	Date	Time	Platform
Amd64_microsoft-windows-dns-client.d_31bf3856ad364e35_6.0.6000.20492_none_fe8947bf7e7f6656.manifest	Not Applicable	701	06-Dec-2006	21:09	Not Applicable
Amd64_microsoft-windows-dns-client_31bf3856ad364e35_6.0.6000.20492_none_3c45221c56f51a2c.manifest	Not Applicable	29,483	06-Dec-2006	21:14	Not Applicable
Dnsapi.dll	6.0.6000.20492	217,600	06-Dec-2006	06:17	x64
Dnscacheugc.exe	6.0.6000.20492	27,648	06-Dec-2006	03:48	x64
Dnsrslvr.dll	6.0.6000.20492	114,688	06-Dec-2006	06:17	x64
Update.mum	Not Applicable	1,995	06-Dec-2006	21:09	Not Applicable

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

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The GUID of a network adapter may change when you upgrade a computer to Windows Vista. The GUID may also change if the network adapter's configuration changes from Dynamic Host Configuration Protocol (DHCP) to static IP and then from static IP to DHCP. The old GUID and its associated IP addresses are not cleared from the DNS client configuration. Therefore, the old IP addresses remain registered for the computer. In this situation, the authoritative zone on a DNS server is populated with both IP addresses that are not valid and IP addresses that are valid. A DNS server cannot distinguish between IP addresses that are valid and IP addresses that are not valid. Therefore, when a DNS server responds to queries from client computers, the server may distribute an IP address that is not valid. If another client computer tries to use this IP address, the computer experiences a connection failure.

For more information about how hotfix packages are named, click the following article number to view the article in the Microsoft Knowledge Base: 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:

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