- You use a DHCP unique identifier (DUID) as a unique identifier in a network environment.
- You use DUID and cable modem identifier mapping in the network.
- You have client computers that are running Windows 7 or Windows Server 2008 R2 in the network environment.
- One of the client computers sends a DHCPv6 message from a cable modem.
- Another client computer sends a DHCPv6 message that has the same DUID from a different cable modem.
- The record for the new DUID and cable modem mapping overwrites the previous record.
- When you run the sysprep command without the /generalize option or you use a different ghost imaging software to build the operating system, the duplicate DUID issue occurs.
- When you run the sysprep command together with the /generalize option, a DHCP client API is called to clear the value of the DUID.
- The DUID of a DHCPv6 message is generated the first time that the DHCP client service starts. The value of the DUID is stored in the Dhcpv6DUID registry entry. If you delete the value of the registry entry, the value is recreated when an interface is enabled or connected on the client computer. The Dhcpv6DUID registry entry is located under the following registry subkey:\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\TCPIP6\Parameters
How to obtain this update
Microsoft UpdateThis update is available from the following Microsoft Update website:
Microsoft Download CenterThe following files are available for download from the Microsoft Download Center:
|All supported x86-based versions of Windows 7||Download the update package now.|
|All supported x64-based versions of Windows 7||Download the update package now.|
|All supported x64-based versions of Windows Server 2008 R2||Download the update package now.|
|All supported IA-64-based versions of Windows Server 2008 R2||Download the update package now.|
PrerequisitesTo apply this update, you must be running one of the following operating systems:
- Windows 7
- Windows 7 Service Pack 1 (SP1)
- Windows Server 2008 R2
- Windows Server 2008 R2 Service Pack 1 (SP1)
Registry informationTo apply this update, you do not have to make any changes to the registry.
Restart requirementYou must restart the computer after you apply this update.
Update replacement informationThis update does not replace a previously released update.
File informationThe global version of this update installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.
Windows 7 and Windows Server 2008 R2 file information notesImportant Windows 7 updates and Windows Server 2008 R2 updates are included in the same packages. However, updates on the Update Request page are listed under both operating systems. To request the update package that applies to one or both operating systems, select the update that is listed under "Windows 7/Windows Server 2008 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each update applies to.
- The files that apply to a specific product, SR_Level (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
Version Product Milestone Service branch 6.1.760
Windows 7 and Windows Server 2008 R2 RTM GDR 6.1.760
Windows 7 and Windows Server 2008 R2 SP1 GDR 6.1.760
Windows 7 and Windows Server 2008 R2 SP1 LDR
- GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain updates in addition to widely released fixes.
- The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows 7 and for Windows Server 2008 R2" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintaining the state of the updated component. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.