Microsoft KB Archive/182781

= Client Connections to Multihomed Server Not Load Balanced =

Article ID: 182781

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Server 4.0, Terminal Server Edition
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 4.0 Standard Edition

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This article was previously published under Q182781





SYMPTOMS
You have a number of clients that are using TCP/IP to connect to a multihomed server that has no IP addresses on the same subnet as the client and the clients are always connecting to the same address on the server, even though the paths to more than one of the addresses are equal.



CAUSE
When the client's NetBT layer attempts to resolve the NetBIOS name to an IP address, it queries the WINS server for the address of a multihomed server and receives a list of addresses that are always in the same order. NetBT then takes that list and sorts it, putting addresses on the same subnet (if any) at the top, followed by addresses in the same network class, and then any remaining addresses. It then starts at the top of this list and pings the first address to make sure it is valid. If it does not get a reply, it will go on to the next address; if it does get a reply, it will use the first address.

The problem is that, within these three categories, the order of addresses is left unchanged from the list provided by the WINS server. This means that, as long as the first address in the list is online, it will be the one that is always used by every client, which does not provide for load balancing.

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

ARTICLE-ID: 161425

TITLE : WinNT 4.0 SP2 Multi-Homed Computer Connection Enhancement



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

152734 How to Obtain the Latest Windows NT 4.0 Service Pack



STATUS
Microsoft has confirmed that this is a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.

Keywords: kbhotfixserver kbqfe kbbug kbfix kbqfe KB182781

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