Microsoft KB Archive/153944

= RAS Server Fails to Autodisconnect Inactive RAS Clients With TCP =

Article ID: 153944

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Workstation 3.5
 * Microsoft Windows NT Workstation 3.51
 * Microsoft Windows NT Server 3.5
 * Microsoft Windows NT Server 3.51

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This article was previously published under Q153944





SYMPTOMS
Your Windows NT Remote Access (RAS) Server fails to disconnect idle RAS clients that have dialed in using the TCP/IP protocol or a combination of the TCP/IP protocol with IPX or NetBEUI.



CAUSE
When the TCP/IP protocol is used over the RAS connection, a Host Announcement from the RAS client causes the RAS server to reset the RAS Autodisconnect timer.

On a Windows NT machine, the Announce parameter defaults to 720 seconds (or 12 minutes). On a Windows NT RAS server, the RAS Autodisconnect parameter defaults to 20 minutes. If your RAS client is also a Windows NT machine, the RAS Autodisconnect timer will reset every 12 minutes, and therefore, the RAS client will never timeout.

If you do not use the TCP/IP protocol over the RAS connection, a Host Announcement from the RAS client will not cause the RAS Autodisconnect parameter to reset.

By design, the RAS Autodisconnect parameter sets the time interval after which inactive connections are terminated. This inactivity is measured by lack of NetBIOS session data transfer. A Host Announcement is not considered NetBIOS session activity.



RESOLUTION
Configure the value of the RAS Autodisconnect parameter so that it is less than the value of the Announce parameter (which specifies the interval of time that a server uses between sending out a Host Announcement).

WARNING: Using the Registry Editor incorrectly can cause serious, system- wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of the Registry Editor can be solved. Use this tool at your own risk.

The Announce parameter can be configured via the following Registry parameter:

  HKEY_LOCAL_MACHINE\SYSTEM

\CurrentControlSet\Services\LanmanServer\parameters

Announce  REG_DWORD   1 to 65535 seconds, Default: 720

The RAS Autodisconnect parameter can be configured via the following Registry parameter:

  HKEY_LOCAL_MACHINE\SYSTEM

\CurrentControlSet\Services\RemoteAccess\parameters

Autodisconnect  REG_DWORD   0 to 1000 minutes, Default: 20



STATUS
Microsoft has confirmed this to be a problem in Windows NT version 3.51. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

Keywords: KB153944

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