Microsoft KB Archive/166186

= OS/2 with TCP/IP May Refuse Socket Connections from Windows NT =

Article ID: 166186

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Workstation 3.51
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 3.51
 * Microsoft Windows NT Server 4.0 Standard Edition

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This article was previously published under Q166186





SYMPTOMS
Windows NT Workstation clients connecting to an OS/2 Warp server running Lotus Notes may experience a problem where the clients are using all of the available sockets on the OS/2 Warp server. This causes a problem where no new clients are able to attach to the Lotus Notes server because there are no sockets available.

Netstat -n shows clients with several connections with a state of FIN-WAIT-2.

Traces show that the computer running Windows NT Workstation is not completing the close correctly by ACKing the server Fin. The OS/2 server retries several times and then resets the connection:

CLIENT (ack-Fin)

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=== 13 0.237 HP   D882D6 Cisco 01522C TCP .A...F, len:    0, seq: 960111578- 960111578, ack:2041908096, win: 7826, src: 2130 dst: 1352  Client 144.250.61.21 IP

Server(ack)

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14 0.239 Cisco 01522C HP   D882D6 TCP .A...., len:    0, seq:2041908096- 2041908096, ack: 960111579, win:28672, src: 1352 dst: 2130  144.250.61.21 Client IP

Server (ack-Fin)

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=== 15 0.244 Cisco 01522C HP   D882D6 TCP .A...F, len:    0, seq:2041908096- 2041908096, ack: 960111579, win:28672, src: 1352 dst: 2130  144.250.61.21 Client IP

Server (ack-Fin)

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=== 19 0.804 Cisco 01522C HP   D882D6 TCP .A...F, len:    0, seq:2041908096- 2041908096, ack: 960111579, win:28672, src: 1352 dst: 2130  144.250.61.21 Client IP. ..

The server continues to ACK-Fin retry and then resets the connection.

Server (reset)

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= 100 319.554 Cisco 01522C HP   D882D6 TCP .A.R.., len:    0, seq:2041908097- 2041908097, ack: 960111579, win:28672, src: 1352 dst: 2130  144.250.61.21 Client IP



CAUSE
There is a problem in Tcpip.sys where the Fin ACK is received from the server and is processed, but it is not acknowledgeed. This problem has been corrected in a new version of Tcpip.sys.



STATUS
Microsoft has confirmed this to be a problem in Windows NT version 4.0. This problem was corrected in the latest Microsoft Windows NT 4.0 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

Microsoft has confirmed this to be a problem in Windows NT version 3.51. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.

Keywords: kbbug kbnetwork KB166186

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