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Q137382: Client RPC Call for Remote APPC LU List Causes SNABASE Error

Article: Q137382
Product(s): Microsoft SNA Server
Version(s): WINDOWS:2.1,2.11
Operating System(s): 
Keyword(s): 
Last Modified: 13-JUN-2001

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The information in this article applies to:

- Microsoft SNA Server, versions 2.1, 2.11, on platform(s):
   - the operating system: Microsoft Windows NT 
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SYMPTOMS
========

SNA Server generates a Dr. Watson error in SNABASE.EXE when a client does a RPC
call to get a list of Remote APPC LUs which are paired with a Local APPC LU. The
SNA Server logs an Event ID 624 in the Windows NT Application Log (as shown in
the Event Viewer) indicating that a SNADUMP.LOG was created for SNABASE.EXE. The
error also generates a DRWTSN32.LOG when it occurs. The following is an excerpt
from a DRWTSN32.LOG that was created following one of the SNABASE errors:

  Application exception occurred:
  App: C:\SNA\system\snabase.exe (pid=139)
  When: 8/7/1995 @ 10:38:21.884
  Exception number: c0000005 (access violation)

Your DRWTSN32.LOG file will appear somewhat different than this example.

NOTE: If using Windows NT Server 3.5, you will have to load the Windows NT
Symbols to get a proper Dr. Watson log when using SNA Server.

After the SNABASE error occurs, the SNA Server stops accepting sessions from SNA
Server clients until the SNA Server is shutdown and restarted.

CAUSE
=====

This error is caused when SNA Server tries to copy (read) a larger range of
memory than is in a memory buffer. This happens when a client makes an RPC call
to get the list of Remote APPC LUs partnered with a particular Local APPC LU and
the number of Remote APPC LUs exceed the size of the client's buffer. The error
only occurs if the memory buffer is located at the end of a 4K page and the
extra memory that SNA Server attempts to read is located on the next uncommitted
page. The buffer size is usually less than one hundred bytes so the probability
of this error is quite small.

RESOLUTION
==========

Microsoft has modified the files, SNABASE.EXE and SNADMOD.DLL, to correct this
problem.


STATUS
======

Microsoft has confirmed this to be a problem in SNA Server for Windows NT. This
problem was corrected in the latest SNA Server for Windows NT, 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

Additional query words: 2.10 2.11 prodsna DRWTSN32.LOG SNADUMP.LOG trap

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Keywords          :  
Technology        : kbAudDeveloper kbSNAServSearch
Version           : WINDOWS:2.1,2.11
Issue type        : kbbug
Solution Type     : kbfix

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