DOCUMENT:Q151201  13-JUN-2001  [sna]
TITLE   :Unbind Hold Causes TN3270 Client 505 Error
PRODUCT :Microsoft SNA Server
PROD/VER:WINDOWS:2.11,2.11 SP1
OPER/SYS:
KEYWORDS:kbnetwork

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The information in this article applies to:

 - Microsoft SNA Server, versions 2.11, 2.11 SP1, on platform(s):
    - the operating system: Microsoft Windows NT 
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SYMPTOMS
========

When you log onto a host system through the SNA Server version 2.11sp1 TN3270E
service, the TN3270 user may receive a 505 error and lose his or her session.

If this occurs, the SNA Server TN3270E service will log the following events into
the Microsoft Windows NT application event log:

 - Event 601
   TN3270(E) session established with client at xxx.xxx.xxx.xxx (port xxxx) using
   LU LAA9.

 - Event 309
   WRITE failed with LUA_STATE_CHECK / LUA_MODE_INCONSISTENCY for xxx.xxx.xxx.xxx
   (port xxxx).

 - Event 603
   TN3270(E) session with client at xxx.xxx.xxx.xxx (port xxxx) using LU LAA9
   terminated abnormally because: TN3270E Service Error 505

 - Event 3065
   A Bind sent by the host for a 3270 session was rejected

 - Event 902
   Logic error in module SNASessionTerminate identified by:.SNAWriteBuffersInUse

CAUSE
=====

When a 3270 user tries to access a host application through a host session
manager, the session manager typically sends an UNBIND(bind forthcoming, or
0x02) followed by a BIND from the host application that was requested.

The TN3270 server was not properly handling the UNBIND, which was causing its LUA
RUI_WRITE call to fail. Therefore, it caused the TN3270 server to end the
session. However, the TN3270 server now correctly ignores this error.

STATUS
======

Microsoft has confirmed this to be a problem in SNA Server versions 2.11 and
2.11.sp1.
This problem was corrected in the latest Microsoft SNA Server 2.11 U.S. Service
Pack. For information on obtaining the service pack, query on the following word
in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K


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

The host sends a data message, followed by an UNBIND (bind forthcoming). The
TN3270 Server issues a response to the data message. However, by that point the
RUI library has received the UNBIND (bind forthcoming) request, and has switched
states to Session Terminating state. In this state it rejects the response
message from the TN3270 Server, with the error LUA_STATE_CHECK /
LUA_MODE_INCONSISTENCY.

Additional query words: prodsna sp1

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Keywords          : kbnetwork 
Technology        : kbAudDeveloper kbSNAServSearch
Version           : WINDOWS:2.11,2.11 SP1
Issue type        : kbbug
Solution Type     : kbfix

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