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Article ID: 193890 - Last Review: February 22, 2007 - Revision: 2.2

This article was previously published under Q193890


A Microsoft Cluster Server (MSCS) with the Windows Internet Name Service (WINS) running may have intermittent connectivity problems with clients on remote networks. This is because the cluster network interface card (NIC) is bound to the WINS TCP/IP Client.

By default, Windows NT binds all protocols to each NIC. The first TCP/IP address configured on each NIC is also bound to the WINS TCP/IP client. When WINS server is installed on a computer running Windows NT Server, the WINS TCP/IP client is bound to each NIC in the server. This binding will register the WINS server as a multihomed server with multiple IP addresses in the multihomed entry.


A WINS server will register the first IP address of each NIC installed in that computer, regardless if the TCP/IP Protocols WINS tab has primary or secondary WINS servers configured. Leaving the WINS tab blank or with no configuration will still result in the WINS server registering all of its first IP addresses with the corresponding sixteenth character hex value for NetBIOS. This behavior is by design.

When a WINS client queries a WINS server for a NetBIOS service, a list of all addresses for a multihomed server will be returned to the client from the WINS server. If the client is on a remote network segment (not on the same LAN segment as the multihomed server), the client will randomly select an address from the list returned from the WINS server.

Because the cluster NICs are typically used only for updates and "heartbeat" communication between the servers in the cluster, there will be no routes to the TCP/IP "network" between the cluster servers. If a client is attempting to contact an MSCS server that has the WINS TCP/IP client enabled on all NICs, the client could select the NIC that has been configured for the cluster, thus causing the client to fail to connect to that server. Disabling the WINS TCP/IP client, (thus disabling NetBIOS), bindings for the NIC configured for the cluster will prevent the WINS server from registering the cluster NIC in the multihomed entry. In Windows 2000 Advanced Server, we also recommend that you disable NetBIOS on the "heartbeat" interface. You can do this by selecting Disable NetBIOS over TCP/IP on the Advanced\WINS tab in TCP/IP Properties for the NIC. NetBIOS is not required for the cluster to communicate. The cluster service will use sockets with RPC for its communication.

To disable the WINS client from the private NIC, double-click the Network icon in Control Panel and click the Bindings tab. Sort by network adapter, and then click the plus sign next to the adapter used for the private interconnect. Select the WINS client and right-click. Click Disable, and then click OK. This change will require restarting the computer; however, make these changes one node at a time to minimize downtime.

Also, for correct and optimal configuration of the public network, ensure that the public network NIC is the first binding (at the top of the binding list) in the TCP/IP bindings.


For additional information, please see the following articles in the Microsoft Knowledge Base:

139985  ( ) WINS Client Fails to Reach a Multihomed Server

150737  ( ) Setting Primary and Secondary WINS Server Options

185786  ( ) Recommended Practices for WINS

  • Microsoft Windows 2000 Advanced Server
  • Microsoft Windows NT Server 4.0 Enterprise Edition
  • Microsoft Cluster Server 1.1
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