XCON: MTA Heap Corruption with Misconfigured TP4/TCP Connection

 Last reviewed: April 15, 1997
Article ID: Q152951
The information in this article applies to:
  • Microsoft Exchange Server, version 4.0

SYMPTOMS

The Microsoft Exchange Message Transfer Agent (MTA) might 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 was 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
Keywords : kbbug4.00 kbfix4.00.sp3 kbusage XCON
Version : 4.0
Platform : WINDOWS

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Last reviewed: April 15, 1997
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