Windows Server 2008 Hyper-V virtual machines generate a Stop error when NLB is configured or when the NLB cluster does not converge as expected

Consider the following scenario:

• You are running a Windows Server 2008 virtual machine in the Hyper-V environment on a Windows Server 2008 host computer.
• You try to create a new Network Load Balancing (NLB) cluster on this virtual machine. Or, you try to add this virtual machine to an existing NLB cluster.

In this scenario, the NLB host on the virtual machine does not converge as expected. Additionally, if a large volume of traffic occurs in the NLB cluster, the guest system on the virtual machine may restart unexpectedly, and you may receive the following Stop error message:Note This Stop error message may indicate that a crash occurred in the Nlb.sys driver.

This convergence problem occurs because of a missing configuration in the Hyper-V environment. The unexpected virtual machine restart occurs because of a deadlock condition in the Nlb.sys driver.


Note: Hotfix is available for this article but this hotfix will be fixed for restart unexpectedly with stop error. 
The convergence problem still existed after installed this hotfix. You must require to fix your NLB configuration refer to Post-installation instructions in RESOLUTION section.

This requirement is limitation for the Windows Server 2008 all editions.

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.

Important Windows Vista and Windows Server 2008 hotfixes are included in the same packages. However, only one of these products may be listed on the “Hotfix Request” page. To request the hotfix package that applies to both Windows Vista and Windows Server 2008, just select the product that is listed on the page.

Prerequisites

To apply this hotfix, you must have the Network Load Balancing feature installed on the virtual machine.

Restart requirement

You do not have to restart the virtual machine after you apply this hotfix. However, you must restart the virtual machine when you configure the virtual machine settings in the Hyper-V environment.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

Post-installation instructions

To resolve this problem, apply this hotfix on the virtual machine. Then, create a new NLB cluster, or add the virtual machine to an existing NLB cluster.

To create a new NLB cluster, follow these steps:

1. Open Network Load Balancing Manager. To do this, click Start, point to Administrative Tools, and then click Network Load Balancing Manager.
2. In the console tree, right-click Network Load Balancing Clusters, and then click New Cluster.
3. In the Host box, type the computer name of the virtual machine that will be the new host, and then click Connect.
4. In the Interfaces available for configuring a new cluster list, select a network adapter for the NLB cluster, and then click Next.
   
   Note If you have not defined a static IP address for the selected interface, you will be prompted to define a static IP address on the next screen.
5. On the New Cluster: Cluster IP Addresses screen, define the virtual IP address for the NLB cluster, note the MAC address in the Network Address property, and then click Next.
   
   Note You will use this MAC address in step 11.
6. Under Cluster operation mode, click Unicast, and then click Next.
7. Complete the rest of the NLB configuration, and then shut down the virtual machine.
   
   Note In this step, the NLB host still does not converge. If you start the virtual machine, you may receive the following error message:
   The bind operation was successful but nlb is not responding to Queries
8. On the host computer, open Hyper-V Manager. To do this, click Start, point to Administrative Tools, and then click Hyper-V Manager.
9. In the details pane, under Virtual Machines, right-click the virtual machine that you want to configure, and then click Settings.
10. In the navigation pane, click the network adapter that you use for the NLB cluster.
11. In the details pane, click Static under Mac Address, and then specify the MAC address that you noted in step 5.
12. Start the virtual machine.
13. Open Network Load Balancing Manager.
14. In the console tree, expand Network Load Balancing Clusters, right-click the NLB host, and then click Host Properties.
15. Click OK to begin the NLB configuration process. The NLB configuration process adds the virtual IP address of the cluster to the TCP/IP properties of the network adapter.

To add the virtual machine to an existing NLB cluster, follow these steps:

1. Open Network Load Balancing Manager. To do this, click Start, point to Administrative Tools, and then click Network Load Balancing Manager.
2. In the console tree, right-click Network Load Balancing Clusters, and then click Connect to Existing.
3. In the Host box, type the computer name of the virtual machine that is part of the existing NLB cluster, and then click Connect.
4. Right-click the cluster, click Cluster Parameters, note the MAC address in the Network Address property, and then click Cancel.
   
   Note You will use this MAC address in step 12.
5. Right-click the NLB cluster, and then click Add Host To Cluster.
6. Specify the name of the new host, and then click Connect. The network adapters that are available for the host are listed at the bottom of the dialog box.
7. Click the network adapter that you want to use for Network Load Balancing, and then click Next. The IP address that is configured on this network adapter is the dedicated IP address for this host.
8. Complete the rest of the NLB configuration, and then shut down the virtual machine.
   
   Note In this step, the NLB host still does not converge. If you start the virtual machine, you may receive the following error message:
   The bind operation was successful but nlb is not responding to Queries
9. On the host computer, open Hyper-V Manager. To do this, click Start, point to Administrative Tools, and then click Hyper-V Manager.
10. In the details pane, under Virtual Machines, right-click the virtual machine that you want to configure, and then click Settings.
11. In the navigation pane, click the network adapter that you use for the NLB cluster.
12. In the details pane, click Static under Mac Address, and then specify the MAC address that you noted in step 4.
13. Start the virtual machine.
14. Open Network Load Balancing Manager.
15. In the console tree, expand Network Load Balancing Clusters, right-click the NLB host, and then click Host Properties.
16. Click OK to begin the NLB configuration process. The NLB configuration process adds the virtual IP address of the cluster to the TCP/IP properties of the network adapter.

Notes

• You must update the Hyper-V configuration static MAC address by using the instructions that are described here when one of the following events occurs:
  • The primary cluster IP address of the NLB cluster changes.
  • The mode of operation for the NLB cluster changes.
• These steps assume that the Network Load Balancing feature is installed. For more information about how to install and how to configure NLB, visit the following Microsoft Web site:
  http://technet2.microsoft.com/windowsserver2008/en/library/d7c4efd2-3cf0-4b3d-9207-4746cab1f9aa1033.mspx

  (http://technet2.microsoft.com/windowsserver2008/en/library/d7c4efd2-3cf0-4b3d-9207-4746cab1f9aa1033.mspx)

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 2008, x86-based versions

Windows Server 2008, Itanium-based versions

Windows Server 2008, x64-based versions

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

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: