Microsoft KB Archive/222545

= X.25 Connection Appears Active After Cable Disconnected =

Article ID: 222545

Article Last Modified on 9/22/2005

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APPLIES TO


 * Microsoft SNA Server 3.0 Service Pack 4
 * Microsoft SNA Server 4.0

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This article was previously published under Q222545





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 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 Therefore, the connection appears to remain active even though it is no longer active.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, click the following article number to view the article in the Microsoft Knowledge Base:

215838 How to Obtain the Latest SNA Server Version 4.0 Service Pack



STATUS
Microsoft has confirmed that this is 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  using Link Service  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.

Keywords: kbbug kbfix kbsna400sp3fix kbqfe kbhotfixserver KB222545

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