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Q155986: NetBT Communication Slow on Multihomed Client

Article: Q155986
Product(s): Microsoft Windows NT
Version(s): winnt:
Operating System(s): 
Keyword(s): kbnetwork
Last Modified: 09-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Server 
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SYMPTOMS
========

When you communicate using NetBIOS over TCP/IP (NetBT) to a device that uses the
second interface of a multihomed Windows NT client, the initial session
establishment is slow.

CAUSE
=====

This problem will only be seen in environments in which the subnets on both
sides of the Windows NT client are not configured to communicate with each
other.

RESOLUTION
==========

Define a route, either per client or on the routers, to allow accessibility to
both adapters on the computer running Windows NT Server.

MORE INFORMATION
================

NetBT first defines the IP address on the source packet of a three-way handshake
using the IP address of the adapter that resolved the name. If this fails, NetBT
uses the IP address of the second adapter. This can cause a delay of up to 50
seconds in the establishment of the connection.

NOTE: In Windows NT version 4.0 and Windows NT version 4.0 Service Pack 2,
significant network connection enhancements have been added to improve
connectivity for multi-homed computers. For detailed information, please see the
following articles in the Microsoft Knowledge base:

  ARTICLE ID: Q161425
  TITLE: WinNT 4.0 SP2 Multihomed Computer Connection Enhancement

  ARTICLE ID: Q166159
  TITLE: NetBIOS Connections from a Multihomed Computer

Additional query words:

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Keywords          : kbnetwork 
Technology        : kbWinNTsearch kbWinNTSsearch
Version           : winnt:

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