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Q239707: TN3270 Clients May Fail to Reconnect to a Host Session

Article: Q239707
Product(s): Microsoft SNA Server
Version(s): WINDOWS:4.0 SP2
Operating System(s): 
Keyword(s): kbsna400sp3fix kbsna400sp2
Last Modified: 01-OCT-1999

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The information in this article applies to:

- Microsoft SNA Server, version 4.0 SP2 
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SYMPTOMS
========

When TN3270 emulators are connecting through the TN3270 server (included with
SNA Server 4.0 Service Pack 2) to a host session, the TN3270 emulators may fail
to automatically reconnect if the session is terminated unexpectedly. The TN3270
emulator will reconnect to a host session if the user presses the Enter key.

The following message may be displayed in the TN3270 emulator window when the
host session is terminated unexpectedly:

  TN3270E Service Error 505

  SNA API verb <verb> failed.

NOTE: This message may not be displayed in the same manner for all TN3270
emulators.

When TN3270 emulators are configured to automatically connect, they successfully
reconnect to a host session after receiving the previous error message. This
occurs without any user intervention when they are connecting to a host session
through a TN3270 server, included with SNA Server versions prior to 4.0 Service
Pack 2 (SP2).

CAUSE
=====

The TN3270 server in SNA Server 4.0 SP2 was updated to use Windows NT I/O
Completion Ports to provide performance improvements. It is the use of I/O
Completion Ports that causes this particular problem to occur. Therefore, the
TN3270 server included with earlier versions of SNA Server does not exhibit this
behavior.

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 version 4.0
SP2. This problem was first corrected in SNA Server version 4.0 Service Pack 3.

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

For additional information about a similar TN3270 issue with SNA Server 4.0 SP2,
please click the article number(s) below to view the article(s) in the Microsoft
Knowledge Base:

  Q230220 Emulators May Fail to Reconnect After Inactivity Timeout

Additional query words:

======================================================================
Keywords          : kbsna400sp3fix kbsna400sp2 
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ400SP2
Version           : WINDOWS:4.0 SP2
Issue type        : kbbug
Solution Type     : kbfix

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