DOCUMENT:Q239132
TITLE   :Exchange Clients Appear to Intermittently Hang During Normal Operation
PRODUCT :Windows NT
PROD/VER:4.0
OPER/SYS:WINDOWS NT
KEYWORD :kbbug4.00 kbfix4.00 

-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Windows NT Server, Enterprise Edition version 4.0
 - Microsoft Windows NT Server version 4.0
-------------------------------------------------------------------------------

SYMPTOMS
========

Microsoft Exchange and Outlook Clients appear to stop responding (hang)
periodically during normal operation when used in conjunction with an Exchange
Server computer that has clients that connect over slower connections.

CAUSE
=====

The remote procedure call (RPC) Receive Any Thread in use by the Microsoft
Exchange Information Store Service is waiting to receive additional information
from a client.

RESOLUTION
==========

A supported fix that corrects this problem is now available from Microsoft, but
it has not been fully regression tested and should be applied only to systems
experiencing this specific problem. If you are not severely affected by this
specific problem, Microsoft recommends that you wait for the next Windows NT 4.0
service pack that contains this fix.

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 on support costs, please go to the following
address on the World Wide Web:

   http://www.microsoft.com/support/supportnet/overview/overview.asp

The English version of this fix should have the following file attributes or
later:

   Date       Time     Size     File name      Platform
   ----------------------------------------------------
   07/22/99   05:31p   37,136   Rpcltscm.dll   i386
   07/22/99   05:30p   59,664   Rpcltscm.dll   Alpha

This hotfix has been posted to the following Internet location as Rpslwfxi.exe
(x86) and Rpslwfxa.exe (Alpha):

   ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/
   hotfixes-postSP5/Rpcltscm-fix/

This fix requires Windows NT 4.0 Service Pack 4 or greater.

NOTE: If this product was already installed on your computer when you purchased
it from the Original Equipment Manufacturer (OEM) and you need this fix, please
call the Pay Per Incident number listed on the above Web site. If you contact
Microsoft to obtain this fix, and if it is determined that you only require the
fix you requested, no fee will be charged. However, if you request additional
technical support, and if your no-charge technical support period has expired,
or if you are not eligible for standard no-charge technical support, you may be
charged a non-refundable fee.

For more information about eligibility for no-charge technical support, see the
following article in the Microsoft Knowledge Base:

   Q154871 Determining If You Are Eligible for No-Charge Technical Support

STATUS
======

Microsoft has confirmed this to be a problem in Windows NT 4.0.

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

Clients that are connecting to the Exchange Server computer over slower
connections have a higher latency in the sending and receiving of data grams.
The RPC Receive Any Thread is waiting on additional data grams before processing
the clients request. This causes other clients that are attempting to
communicate on the Receive Any thread to the Exchange Information Store to
appear to hang while waiting for a response from the Exchange Server computer.

For additional information on performance issues, please refer to the following
article in the Microsoft Knowledge Base:

   Q232512 TCP/IP may Retransmit Packets Prematurely

Additional query words: 4.00 exchange performance slow client 
============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.