TN3270 Clients May Fail to Reconnect to a Host Session

ID: Q239707

The information in this article applies to:

Microsoft SNA Server, version 4.0 SP2

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 : sna4sp3fix sna4sp2
Version : WINDOWS:4.0 SP2
Platform : WINDOWS
Issue type : kbbug