Microsoft KB Archive/103470

= NetBIOS Name Conflicts When NetBEUI Used on Multiple NICs =

Article ID: 103470

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Advanced Server 3.1
 * Microsoft Windows NT Workstation 3.1
 * Microsoft Windows NT Advanced Server 3.1
 * Microsoft Windows NT Server 3.5
 * Microsoft Windows NT Server 3.51
 * Microsoft Windows NT Server 4.0 Standard Edition
 * Microsoft Windows NT Workstation 3.5
 * Microsoft Windows NT Workstation 3.51
 * Microsoft Windows NT Workstation 4.0 Developer Edition

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This article was previously published under Q103470



SUMMARY
You can configure multiple network interface cards (NICs, also called network adapters) in a computer (multihomed) for use on the same network segment, but no two network adapters on the same segment in the computer can use NetBIOS. When you install NetBEUI on a multihomed computer, it violates this restriction.



MORE INFORMATION
When you install NetBEUI on a multihomed computer, NetBEUI binds to all available network adapters in the computer regardless of whether they are on the same physical network segment. If a computer containing two or more network adapters uses the same protocol on more than one network adapter in a given network segment, the computer sees duplicate computer names due to the resulting NetBIOS name conflict, generates an error, and fails to start system services correctly. This also occurs if both segments are bridged.

The event log may show an Event ID 2505 error (duplicate name on the network). The error may appear in the event log as either of the following messages:


 * Event ID : 2505

The server could not bind to the transport/device/netbt_ because another computer on the network has the same name. The server could not start.
 * Event ID : 2505

The server could not bind to the transport/device/nbf_ because another computer on the network has the same name. The server could not start.

The event log may also show:


 * Event ID: 3870

Source: workstation is not a valid computer name.

This problem does not affect routable protocols (TCP/IP, AppleTalk and NWLink) because when you install or reconfigure them you have to choose a network adapter in Control Panel's Network configuration window, and this automatically disables the protocol's bindings to other adapters. When installing TCP/IP, for instance, you are forced to provide unique IP addresses to each network adapter, then choose one network adapter as the "Windows Networking Adapter" in the "Windows Networking on TCP/IP (NetBIOS)" box of the TCP/IP Configuration window.

You can manually configure multiple network adapters in a computer by disabling NetBEUI bindings to network adapters other than the one you want to use for the NetBEUI protocol. To do this, disable the following bindings:


 * Server to NetBEUI protocol to to
 * Workstation to NetBEUI protocol to to
 * NetBEUI protocol to to
 * NetBIOS Interface to NetBEUI protocol to to

When you have disabled all of these bindings, network operations can proceed.

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

ARTICLE-ID: 131736

TITLE : TCP/IP: Load Balancing vs. Distributed Network Sessions

Additional query words: duplicate multihomed bridged netbf netbeui event 2504 duplicate name server could not bind 3.10

Keywords: kbnetwork KB103470

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