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Event ID 91 — 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: 91
Source: Microsoft-Windows-NLB
Version: 6.0
Symbolic Name: MSG_ERROR_HOST_ID
Message: NLB cluster [%2]: NLB received a heartbeat from a host with an invalid ID %5. Please check the NLB configuration of all hosts and make sure that each has a unique host priority (a number between 1 and 32).

Resolve

Ensure that all NLB hosts have unique host priorities

If a Network Load Balancing (NLB) host has a host priority that is identical to the host priority on another host, or the host priority is not valid, the cluster will not converge until the problem is corrected. The host priority must be a number from 1 through 32, and this value must be unique for all hosts in the cluster.

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 ensure that all NLB hosts have a unique host priority:

  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. Click the Port Rules tab. In the Defined port rules list, review each host to make sure that each host has a unique host identifier.
  5. If there are host identifiers that are not unique, right-click the host for which you want to reconfigure the host identifier, and then click Host Properties.
  6. Click the Host Parameters tab, and in Priority (unique host identifier), specify a value between 1 and 32.

 

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