DOCUMENT:Q152951  30-MAR-1999  [exchange]
TITLE   :XCON: MTA Heap Corruption With Misconfigured TP4/TCP Connection
PRODUCT :Microsoft Exchange
PROD/VER:winnt:4.0
OPER/SYS:
KEYWORDS:kbusage

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The information in this article applies to:

 - Microsoft Exchange Server, version 4.0 
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SYMPTOMS
========

The Microsoft Exchange Message Transfer Agent (MTA) may experience heap
corruption if there is a misconfigured incoming TCP/IP or TP4 connection. The
heap corruption will exhibit itself as Dr. Watson errors in the MTA.

CAUSE
=====

Microsoft Exchange Server is leaking buffers from SBPDSACP in the WinSock code.
WINSOCK DMOD (TP4/TCP) creates too many threads when many connections are
started and stopped. Threads of different types (TP4/TCP) can be created on the
same Thread Control Block (CB) causing two WINSOCK threads to update the
pointers in a select call simultaneously. This can cause heap corruption.

STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Exchange Server
version 4.0. This problem was corrected in the latest Microsoft Exchange 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: Dr. Watson Crash

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Keywords          : kbusage 
Technology        : kbExchangeSearch kbExchange400 kbZNotKeyword2
Version           : winnt:4.0
Issue type        : kbbug
Solution Type     : kbfix

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