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Q242528: Time-Out to Unreachable Computers Is Excessive

Article: Q242528
Product(s): Microsoft Windows NT
Version(s): winnt:4.0
Operating System(s): 
Keyword(s): 
Last Modified: 06-AUG-2002

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The information in this article applies to:

- Microsoft Windows NT Server version 4.0, Terminal Server Edition 
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IMPORTANT: This article contains information about modifying the registry. Before you 
modify the registry, make sure to back it up and make sure that you understand how to restore 
the registry if a problem occurs. For information about how to back up, restore, and edit the 
registry, click the following article number to view the article in the Microsoft Knowledge Base:

  Q256986 Description of the Microsoft Windows Registry

SYMPTOMS
========

When you are attempting to connect to a computer that is unreachable in a
Terminal Server session, you may experience an excessive delay before the
attempted connection times out. The typical, expected delay of less than a
minute does not occur. Instead, Terminal Server may take from 90 seconds to 20
minutes before an "Unsuccessful" error message is returned. This may cause the
program that requested the network connection to stop responding (hang).

CAUSE
=====

There are several iterations of calls to the redirector to establish a
connection. First, the system context attempts a connection to
\\<server>\ipc$, which allocates a server list entry and attempts to
connect. The returned status is "0xC00000BE invalid connection," and the last
connect time is set in the server entry. Then, the application context attempts
a connection to \\<server>\<share>, which allocates a second server
list entry and attempts to connect. During this time, the cleanup thread wakes
up and determines that the first server list entry has expired and dereferences
and frees it. The second connection attempt then returns "failure 0xC00000BE."
The driver then reiterates on \\<server>\ipc$ by using the Multiple UNC
Provider (MUP) and does not find the server list entry. A new one is allocated
and a connection attempt is made. During this time, the cleanup thread wakes up
again and determines that \\<server>\<share> has expired and
dereferences and frees it. This continues until the timing is just right and
both server list entries can be found. Note that these connection attempts can
take a minute or so each because the server does not exist and Windows is
relying on a time-out to determine this.

RESOLUTION
==========

A supported fix is now available from Microsoft, but it is only intended to
correct the problem that is described in this article. Only apply it to systems
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, Terminal Server Edition,
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 usual support costs will apply to
additional support questions and issues that do not qualify for the specific
update in question.

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

  Date      Time               Size       File name     Platform
  --------------------------------------------------------------
  10/28/1999   11:03 PM        266,576    Rdr.sys       Intel
  10/28/1999   11:09 PM        510,032    Rdr.sys       Alpha



WORKAROUND
==========

WARNING: If you use Registry Editor incorrectly, you may cause serious problems
that may require you to reinstall your operating system. Microsoft cannot
guarantee that you can solve problems that result from using Registry Editor
incorrectly. Use Registry Editor at your own risk.
One way to work around the problem is to configure the following registry
setting:

  HKLM\System\CurrentControlSet\Services\RDR\Parameters

  Value Name: FailedConnectTimeout
  Data Type: REG_DWORD
  Data: 0x80 (This is about 120 seconds)

This registry setting does not really solve the problem, but avoids it. The
second attempt to connect should really be locating the server list entry rather
than reattempting the connection. The redirector code has been changed to
prevent the need for the futile second connection attempt.

STATUS
======

Microsoft has confirmed that this is a problem in the Microsoft products that
are listed at the beginning of this article.

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

The length of the hang changes depending on the WINS configuration and the name
resolution used by the destination server and Terminal Server. If the
destination server's IP address cannot be resolved, the hang occurs for less
than 2 minutes.

If the destination server's IP address resolves successfully, Terminal Server
then attempts a connection. Address Resolution Protocol (ARP) takes about 50
seconds for each unsuccessful attempted connection, causing the program to hang
for more than 20 minutes.


Additional query words:

======================================================================
Keywords          :  
Technology        : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTS400search kbNTTermServ400 kbNTTermServSearch
Version           : winnt:4.0
Hardware          : ALPHA x86
Issue type        : kbbug
Solution Type     : kbfix

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