NetBIOS Name Conflicts When NetBEUI Used on Multiple NICs

 Last reviewed: January 5, 1998
Article ID: Q103470
The information in this article applies to:
  • Microsoft Windows NT operating system version 3.1
  • Microsoft Windows NT Advanced Server version 3.1
  • Microsoft Windows NT Workstation versions 3.5 and 3.51
  • Microsoft Windows NT Server versions 3.5 and 3.51
  • Microsoft Windows NT Server version 4.0
  • Microsoft Windows NT Workstation version 4.0

You can configure multiple network interface cards (NICs, also called network adapters) in a PC (multihomed) for use on the same network segment, but no two NICs on the same segment in the PC can use NetBIOS.

Installing NetBEUI violates this restriction because NetBEUI binds to all available adapters in the machine regardless of whether they are on the same physical network segment. If a PC containing two or more NICs uses the same protocol on more than one NIC in a given network segment, the system sees duplicate machine names due to the resulting NetBIOS name conflict, generates an error, and fails to start system services correctly. This will also occur if both segments are bridged.

This problem does not affect routable protocols (TCP/IP, AppleTalk and NWLink) because when you install or reconfigure them you have to choose a NIC 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 system NIC, then choose one NIC 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 NICs in a PC by disabling NetBEUI bindings to network adapters other than the one you want to use for the NetBEUI protocol. Disable the following bindings:

  • Server to NetBEUI protocol to <adapter driver> to <adapter>
  • Workstation to NetBEUI protocol to <adapter driver> to <adapter>
  • NetBEUI protocol to <adapter driver> to <adapter>
  • NetBIOS Interface to NetBEUI protocol to <adapter driver> to <adapter>

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: Q131736
   TITLE     : TCP/IP: Load Balancing vs. Distributed Network Sessions

Additional reference words: duplicate multihomed bridged netbf netbeui
event 2504 duplicate name server could not bind
Keywords : NTPROTOCOL NTSrvWkst kbnetwork
Version : 3.1 3.5 3.51 4.0
Platform : WINDOWS

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Last reviewed: January 5, 1998
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