FIX: 5250 Client in TN5250 Mode May Stop Responding (327297)


The information in this article applies to:

  • Microsoft Host Integration Server 2000
This article was previously published under Q327297

SYMPTOMS

While in TN5250 mode, 5250 Client may stop responding when you type data in some AS/400 programs or in some AS/400 menus. When the problem occurs, the Input Inhibited (II) status indicator and the Keystroke Buffering (KB) status indicator are highlighted in the 5250 Client Status line at the bottom of the 5250 session window.

CAUSE

This problem can occur if an AS/400 sends data to the TN5250 client that includes X'FF' as part of a SNA General Data Stream (GDS) message.

The Telnet (TN) specifications define X'FF' as an Interpret As Command (IAC) character. If an SNA GDS message contains an X'FF' character, the TN5250 server must replace this character with X'FFFF' to indicate that the character is not to be treated as an IAC character.

5250 Client cannot correctly parse X'FFFF' if it is part of a GDS header. The result is that the data received from the AS/400 is not interpreted correctly, which causes 5250 Client to wait for additional data.

RESOLUTION

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Microsoft Host Integration Server 2000 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel. 
Date          Time   Version      Size       File name
-------------------------------------------------------
09-Aug-2002  12:21   5.0.0.900   33,040    Wstn5250.dll

NOTE: Because of file dependencies, the most recent fix that contains the preceding files may also contain additional files.

STATUS

Microsoft has confirmed that this is a problem in Microsoft Host Integration Server 2000.

MORE INFORMATION

For more information about SNA GDS messages, see the IBM SNA Formats (GA27-3136) manual.

For additional information about the 5250 Status indicators, click the article number below to view the article in the Microsoft Knowledge Base:

107117 5250 Applet Status Line

For more information about the IAC character, see the following Telnet RFC:

RFC 764
http://www.faqs.org/rfcs/rfc764.html

Modification Type:MinorLast Reviewed:10/11/2005
Keywords:kbHotfixServer kbQFE kbBug kbfix kbQFE KB327297 kbAudDeveloper
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