Microsoft KB Archive/259241

= Nbtstat and Nbt Performance Counters May Not Work with Many Network Interfaces =

PSS ID Number: 259241

Article Last Modified on 10/16/2002

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The information in this article applies to:


 * Microsoft Windows NT Workstation 4.0
 * Microsoft Windows NT Server 4.0
 * Microsoft Windows NT Server, Enterprise Edition 4.0

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This article was previously published under Q259241



SYMPTOMS
When you are using a large number of network interfaces, you may experience any of the following symptoms:  When you run Nbtstat.exe from a command prompt, nothing happens and the command prompts returns. When you are using Performance Monitor, the following error message is generated frequently in the Application event log:

Event Type: Error

Event Source: perfctrs

Event Category: None

Event ID: 3101

Description: Unable to read IO control information from NBT device.





CAUSE
An internal buffer is used to read the NetBT bindings information from the registry. Problems can occur if the information in the registry exceeds the size of this buffer.

This problem is likely to occur if there are more than 25 network interfaces bound to NetBT. For example, this problem might occur if you configure a Remote Access Service (RAS) server with 30 dial-out lines.



RESOLUTION
A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Windows NT 4.0 service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix should have the following file attributes or later:   Date       Time     Size     File name     Platform ---  5/24/2000  03:06am  19,728   Nbtstat.exe   Intel 5/24/2000 03:06am  44,304   Perfctrs.dll  Intel



WORKAROUND
Netbt.sys is a driver that is required for NetBIOS over TCP/IP connections. It is required for connections from and to the local computer only. Connections from other computers that pass though a local computer that is acting as a router work. Typically, this functionality is not required for all interfaces (for example, for connections from and to the Internet).

To work around this problem, use any of the following methods:
 * Unbind Netbt from all interfaces that are not used for NetBIOS over TCP/IP connections.
 * Reduce the number of interfaces until the problem does not occur.



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

Keywords: kbbug kbenv kberrmsg kbnetwork kbQFE KB259241

Technology: kbWinNT400search kbWinNTS400 kbWinNTS400search kbWinNTsearch kbWinNTSEnt400 kbWinNTSEntSearch kbWinNTSsearch kbWinNTW400 kbWinNTW400search kbWinNTWsearch

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