TN3270 Clients May Fail to Reconnect to a Host Session (239707)

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, 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

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: