Windows NT SP4 May Cause Loss of TCP/IP Connectivity in WLBS Host

When you apply Windows NT 4.0 Service Pack 4 (SP4) to your computer running Windows NT Load Balancing Service (WLBS), the following problems may occur:

• On a WLBS host that consistently experiences heavy loads of traffic, WLBS may stop servicing client requests. Although the cluster can converge, IP connectivity is disrupted.
• The WLBS cluster does not converge. The 'wlbs query' command returns:
  "converging with the following hosts:".
  NOTE: The command should at least display the WLBS cluster converging with itself, even if it was the only host in the cluster.

This problem occurs because Network Driver Interface Specification (NDIS) incorrectly thinks WLBS is out of resources and stops sending WLBS packets to the Media Access Control driver. This behavior occurs because of a WLBS incompatibility with NDIS performance enhancements made in SP4.

Windows NT Server or Workstation 4.0

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or the individual software update. For more information, click the following article number to view the article in the Microsoft Knowledge Base: For information about how to obtain the individual software update, contact Microsoft Product Support Services. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

Windows NT Server 4.0, Terminal Server Edition

To resolve this problem, obtain the latest service pack for Windows NT Server 4.0, Terminal Server Edition. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Windows NT Server version 4.0, Terminal Server Edition Service Pack 6.

For more information about the NDIS changes in Windows NT 4.0 Service Pack 4, click the following article number to view the article in the Microsoft Knowledge Base: