Microsoft KB Archive/152705

= Multihomed WINS Servers Send Name Query Responses =

Article ID: 152705

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT 3.51 Service Pack 4

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This article was previously published under Q152705





SYMPTOMS
WINS clients connect to non-local interfaces on multihomed servers.

Unexpected WINS name resolution fails with multihomed WINS servers when IP routers fail.



CAUSE
Physically multihomed WINS servers are supported under Windows NT 3.51 service pack 4, which allows the WINS server to bind to each instance of NetBT (the first IP address on each network interface card (NIC)).

Although the WINS server will accept name registrations and queries on each of these IP addresses, it will respond using the first NIC bound to NetBT. This NIC is the interface with the lowest binding number in the Installed Adapter Cards list in the Control Panel Network application.

If a successful name query response is sent from an IP address that the client does not recognize as a WINS server (that is, it is not configured as the client's primary or secondary WINS server), it will only use the first address in the response list rather than passing all the record entries received through a ChooseBestIPAddress routine. The ChooseBestIPAddress routine selects the best target IP address based on the following criteria:


 * An address on the same subnet as the calling instance of NetBT
 * An address on the same subnet as any NIC in the local machine
 * An address chosen at random from the list

Although the target system may have a connection on the client's local subnet, the client may connect to an address in another subnet, depending on the order in which the server registered its IP addresses with WINS.



WORKAROUND
To allow the client to recognize a WINS name query response when dual-homed WINS servers are deployed, set WINS client's primary and secondary WINS server addresses to the first and second IP addresses of the WINS server.

This workaround does not address the operational issues that arise if the network path from the client to the WINS server's primary interface fails.



STATUS
Microsoft has confirmed this to be a problem in Windows NT version 3.51 Service Pack 4. This problem was corrected in the latest Windows NT 3.51 U.S. Service Pack. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

Additional query words: prodnt tcpip

Keywords: kbnetwork KB152705

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