Microsoft KB Archive/247768

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No Load Balancing When Obtaining Access to a Cluster Virtual IP Address from a Cluster Host

Article ID: 247768

Article Last Modified on 11/1/2006


  • Microsoft Windows NT Server 4.0 Enterprise Edition
  • Microsoft Windows NT Load Balancing Service

This article was previously published under Q247768


When you obtain access to a cluster virtual Internet Protocol (IP) address from a cluster node of the same cluster, the connection is always made to the local computer.


This behavior occurs because the cluster IP address is interpreted as a local address, so the Transport Control Protocol/Internet Protocol (TCP/IP) stack loops the connection back to the local host. Because of this, the packets are never sent to the network, and Windows Load Balancing Service (WLBS) fault tolerance and load balancing are not effective.


To obtain access to other hosts on the cluster, the dedicated IP address of the respective node must be used. To achieve load balancing with the client running on a WLBS cluster, the server program must reside on a different cluster.


This behavior is by design.

Keywords: kbnetwork kbprb KB247768