DOCUMENT:Q257379  08-MAY-2002  [winnt]
TITLE   :Wspsrv.exe Exception: Access Violation (0xC0000005)
PRODUCT :Microsoft Windows NT
PROD/VER::2.0,4.0,4.x,5.0,5.5
OPER/SYS:
KEYWORDS:kberrmsg kbWinNT400PreSP7Fix

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The information in this article applies to:

 - Microsoft Windows NT Server version 4.0 
 - Microsoft Proxy Server version 2.0 
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SYMPTOMS
========

The Proxy Server 2.0 Winsock Proxy service may stop and may generate a
Drwtsn32.log file. The error message is:

   WSPSRV.EXE Exception: access violation (0xC0000005)

The module causing the access violation is Rnr20.dll.

CAUSE
=====

This problem can occur if you use Proxy Server 2.0 to server proxy for Exchange
Server. Reverse Domain Name Service (DNS) lookups generated by domain filters on
either the proxy server or the Exchange SMTP service may trigger the access
violation.

The access violation is actually being caused by single-threaded programs
generating an excessive number of GetXbyYData calls.

RESOLUTION
==========

A supported fix is now available from Microsoft, but it is only intended to
correct the problem that is described in this article. Apply it only to
computers that are experiencing this specific problem. This fix may receive
additional testing. Therefore, if you are not severely affected by this 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 about support costs, visit the following Microsoft
Web site:

   http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

NOTE: In special cases, charges that are ordinarily incurred for support calls
may be canceled if a Microsoft Support Professional determines that a specific
update will resolve your problem. The typical support costs will apply to
additional support questions and issues that do not qualify for the specific
update in question.

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

   Date        Time      Size      File name   
   -------------------------------------------
   05/01/00    06:48p    77,584    Mswsock.dll
   05/01/00    06:48p    45,840    Rnr20.dll
   05/01/00    06:48p    20,752    Wsock32.dll



To prevent this problem from occurring, disable anything that may create a large
number of reverse DNS lookups.

In Proxy Server 2.0, disable domain filters.

In Exchange Server, disable SMTP reverse DNS lookups. For additional information
about how to do this, click the article number below to view the article in the
Microsoft Knowledge Base:

   Q190026 XFOR: SMTP Protocol Log Only Shows Connection Established Else

STATUS
======

Microsoft has confirmed that this is a problem in Windows NT 4.0.

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

This problem does not occur in Microsoft Windows 2000.


Additional query words:

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Keywords          : kberrmsg kbWinNT400PreSP7Fix 
Technology        : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbAudDeveloper kbProxyServSearch kbProxyServ200
Version           : :2.0,4.0,4.x,5.0,5.5
Hardware          : ALPHA x86
Issue type        : kbbug
Solution Type     : kbfix

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