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Event ID 73 — NLB Host Configuration

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Applies To: Windows Server 2008

Hosts in a Network Load Balancing (NLB) cluster are configured to load balance network traffic. Host configuration is set by using NLB Manager, and if it is not configured properly, the NLB cluster may not function correctly.

 

Event Details

Product: Windows Operating System
ID: 73
Source: Microsoft-Windows-NLB
Version: 6.0
Symbolic Name: MSG_ERROR_CL_IGMP_ADDR
Message: NLB cluster [%2]: The NLB cluster IGMP multicast IP address %3 is invalid. Please check the NLB configuration and make sure that the cluster IGMP multicast IP address is in a valid format.

Resolve

Check that the cluster IGMP multicast address is valid

If the Network Load Balancing (NLB) cluster detects that the Internet Group Management Protocol (IGMP) multicast IP address is invalid, you should check the NLB configuration and make sure that the cluster IGMP multicast IP address is in a valid format.

When you are using NLB Manager, you must be a member of the Administrators group on the host that you are configuring, or you must have been delegated the appropriate authority. If you are configuring a cluster or host by running NLB Manager from a computer that is not part of the cluster, you do not have to be a member of the Administrators group on that computer.

To check the IGMP address:

  1. Click Start, click Administrative Tools, and then click Network Load Balancing Manager. You can also open NLB Manager by typing Nlbmgr at a command prompt.
  2. If NLB Manager does not already list the cluster, connect to the cluster.
  3. Right-click the cluster, and then click Cluster Properties.
  4. Ensure that the IGMP multicast check box is selected to enable IGMP support on all hosts in the cluster. When you enable IGMP support, the allowed multicast IP address is restricted to the standard class D range; that is, 224.0.0.0 to 239.255.255.255.

Verify

When you are using nlb.exe, you must be a member of the Administrators group on the host that you are configuring, or you must have been delegated the appropriate authority. If you are configuring a cluster or host by running nlb.exe from a computer that is not part of the cluster, you do not have to be a member of the Administrators group on that computer.

To verify that all Network Load Balancing (NLB) hosts are in the converged state:

  1. Open an elevated Command Prompt window. Click Start, point to All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.
  2. Type nlb.exe query, which displays the current cluster state and the list of host priorities for the current hosts of the cluster.
  3. Confirm that all hosts display converged as their current state.

NLB Host Configuration

NLB Cluster