FIX: Unable to Login Using Named Pipes After Login Failure
  
PSS ID Number: Q114120
Article last modified on 01-24-1995
 
4.20
 
WINDOWS
 

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The information in this article applies to:
 
 - Microsoft SQL Server Programmer's Toolkit, version 4.2
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BUG# 8961 (4.2)
 
SYMPTOMS
========
 
After a login failure occurs, further attempts to connect from the same
application continue to fail. Other applications can connect to the same or
other SQL Servers without a problem. You can restart Windows to clear up
the problem.
 
If the list of currently loaded modules is examined with a utility,
DBNMP3.DLL will be loaded even though there are no DB-Library (DB-Lib)
applications running. Using a utility to unload the DBNMP3.DLL will also
clear up the problem.
 
CAUSE
=====
 
If a login attempt fails, DB-Library does not unload the Named Pipe Network
Library (Net-Library) DBNMP3.DLL. Usually, this does not cause a problem.
However, in certain instances, if the login failure occurs because of
network error during the login process, the Named Pipes Net-Library can be
left in a state that prevents further connections by the application that
had the login failure.
 
The login error is not always apparent to the user. In applications that
use a "make/break" style of connection to the SQL Server, the failure can
occur when the application attempts to reconnect to the SQL Server in
response to some user request. Thus, it appears to the user that the
application has suddenly stopped working.
 
WORKAROUND
==========
 
Restart Windows. Or, if a utility is available that can unload a module,
unloading DBNMP3.DLL will usually clear up the problem. When attempting to
unload DBNMP3.DLL, be sure that there are no other DB-Library or ODBC
applications running that use the Named Pipes Net-Library.
 
STATUS
======
 
Microsoft has confirmed this to be a problem in DB-Library version 4.20.00.
This problem was corrected in DB-Library version 4.21.00. For more
information, contact your primary support provider.
 
Additional reference words: 4.2 connect dblib
KBCategory: kbnetwork
KBSubCategory: SSrvProg SSrvLan SSrvDB_Lib
 
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Copyright Microsoft Corporation 1995.
