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

ID: Q228942

The information in this article applies to:

Microsoft Windows NT Server version 4.0 SP4
Windows NT Load Balancing Service 1.0

SYMPTOMS

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.

CAUSE

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.

RESOLUTION

A supported fix that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem. If you are not severely affected by this specific problem, Microsoft recommends that you wait for the next Windows NT 4.0 service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. 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:

http://www.microsoft.com/support/supportnet/overview/overview.asp

The English version of this fix should have the following file attributes or later:


   Date       Time          Size      File name   Platform
   -------------------------------------------------------
   03/25/99   10:02:11 am   121,552   Ndis.sys    x86

NOTE: If this product was already installed on your computer when you purchased it from the Original Equipment Manufacturer (OEM) and you need this fix, please call the Pay Per Incident number listed on the above Web site. If you contact Microsoft to obtain this fix, and if it is determined that you only require the fix you requested, no fee will be charged. However, if you request additional technical support, and if your no-charge technical support period has expired, or if you are not eligible for standard no-charge technical support, you may be charged a non-refundable fee.

For more information about eligibility for no-charge technical support, see the following article in the Microsoft Knowledge Base:

Q154871 Determining If You Are Eligible for No-Charge Technical Support

STATUS

Microsoft has confirmed this to be a problem in Windows NT 4.0.

MORE INFORMATION

For more information on the NDIS changes in SP4, please see the following articles in the Microsoft Knowledge Base:

Q217305 Full Duplex Support with Windows NT and Q214455 Ndis Intermediate Driver Model

Additional query words:


Keywords          : kbbug4.00 kbfix4.00 
Version           : winnt:1.0,4.0 SP4
Platform          : winnt 
Issue type        : kbbug

Last Reviewed: July 2, 1999