Microsoft KB Archive/114120

FIX: Unable to Login Using Named Pipes After Login Failure

PSS ID Number: Q114120 Article last modified on 01-24-1995

4.20

WINDOWS

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.