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Q222545: X.25 Connection Appears Active After Cable Disconnected

Article: Q222545
Product(s): Microsoft SNA Server
Version(s): WINDOWS:3.0,3.0SP1,3.0SP2,3.0SP3,4.0,4.0SP1,4.0SP2
Operating System(s): 
Keyword(s): kbsna400sp3fix
Last Modified: 08-MAY-2002

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The information in this article applies to:

- Microsoft SNA Server, versions 3.0, 3.0SP1, 3.0SP2, 3.0SP3, 4.0, 4.0SP1, 4.0SP2 
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SYMPTOMS
========

An X.25 connection to a remote device (that is, mainframe) may not generate a
connection outage when the X.25 cable is disconnected from a X.25 adapter
installed in an SNA Server system. SNA Server Manager continues to show the
connection in an Active state even after the cable is disconnected. The
following event may be logged in the Windows NT Application Event Log on the SNA
Server system when this occurs:

  Event ID: 325
  Source: SNA X.25 Link Service
  Description: Driver <link service driver name> DSR has gone OFF:
  probable modem failure.

All active sessions using the X.25 connection will be lost when the X.25 cable is
disconnected from the X.25 adapter even though the connection appears to be
active when looking at its status in SNA Server Manager.

NOTE: This problem may occur with any X.25 adapter that uses SNA Server's
Ibmx25.dll "dumb card" driver interface. This driver interface is published in
the appendix of the SNA Device Interface Specification (SNADIS) guide, which is
included in the SNA Server SDK.


CAUSE
=====

A connection outage is not generated when the X.25 cable is disconnected from
the X.25 adapter because an incorrect variable is passed to the function that is
responsible for generating the outage. The result is that an outage is not
generated, which means that the X.25 link service does not inform the SNA Server
service that the connection has been lost. Therefore, the connection appears to
remain active even though it is no longer active.


RESOLUTION
==========

To resolve this problem, obtain the latest service pack for SNA Server version
4.0. For additional information, please see the following article in the
Microsoft Knowledge Base:

  Q215838 How to Obtain the Latest SNA Server Version 4.0 Service Pack


STATUS
======

Microsoft has confirmed this to be a problem in Microsoft SNA Server versions
3.0, 3.0 SP1, 3.0 SP2, 3.0 SP3, 4.0, 4.0 SP1, and 4.0 SP2. This problem was
first corrected in SNA Server version 4.0 Service Pack 3.

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

Host connection failures normally result in a connection outage error. When a
connection outage is generated, the status of the connection will change to
either Pending or Inactive when viewed in SNA Server Manager. In addition, an
Event 23 message is logged in the Windows NT Application Event Log when a link
service detects an outage. The Event 23 message includes a connection specific
qualifier (that is, return code) that indicates the type of failure that
occurred. The following are some of the common X.25 connection outages that may
occur:

- X'37' - Loss of a virtual circuit.

- X'60' - The switched virtual circuit to the host has been cleared down
  (broken) either by the host or by the X.25 network itself.

- X'61' - The permanent virtual circuit to the host has been cleared down
  (broken) either by the host or by the X.25 network itself.

- X'62' - An attempt to connect to the host through a switched virtual circuit
  has failed.

As an example, an X.25 link service will log the following message when the cable
between the modems is disconnected:

  Event ID: 23
  Source: SNA X.25 Link Service
  Description: Connection <connection_name> using Link Service
  <link_service_name> failed.

  Qualifier = X'61'

After applying this update, the X.25 link service will generate an outage when
the X.25 cable is disconnected from the X.25 adapter.

Additional query words:

======================================================================
Keywords          : kbsna400sp3fix 
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ300 kbSNAServ400
Version           : WINDOWS:3.0,3.0SP1,3.0SP2,3.0SP3,4.0,4.0SP1,4.0SP2
Issue type        : kbbug
Solution Type     : kbfix

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