Article ID: 140536
Article Last Modified on 3/14/2005
APPLIES TO
- Microsoft Visual FoxPro 3.0 Standard Edition
- Microsoft Data Access Components 2.5
This article was previously published under Q140536
SYMPTOMS
When you try to connect to a data source on a SQL Server, you may receive an error, which may be intermittent, that is similar to this:
CAUSE
This often shows up on workstations running Windows for Workgroups 3.11, servers that were originally running Windows NT 3.1 but have been upgraded to Windows NT 3.5 or 3.51, and on systems using named pipes over Microsoft's NWLINK network redirector.
NWLINK is Microsoft's IPX/SPX compatible network redirector. Windows NT 3.5 introduced a new feature called Direct Hosting, where the workstation and server bypass the NETBIOS layer of the protocol. This allows the two to talk more directly, eliminates a layer of overhead, and generally speeds workstation/server interactions. However, when direct hosting is used with older versions of the redirector, communications become unreliable.
RESOLUTION
There are basically two resolutions, either replace the redirector or turn off direct hosting. It is best to update the redirector to retain the speed of direct hosting and to use the most recent versions of the drivers.
To replace the redirector, you need to find the files that comprise it and copy them to the Windows\System subdirectory. The updated files are:
NDIS.386
NET.EXE
NETAPI.DLL
NWNBLINK.386
VNETSUP.386
VREDIR.386
They can be found on the Windows NT compact disc. For Windows NT 3.5, they are located in \Clients\Wfw\Update. Note that these files are only for Windows for Workgroups 3.11.
To turn off direct hosting, open the System.ini file on the Windows for Workgroups client, find the [network] section, and add this line:
DirectHost=off
STATUS
Microsoft is researching this behavior and will post new information here in the Microsoft Knowledge Base as it becomes available.
Additional query words: connection VFoxWin
Keywords: kbnetwork kbprb KB140536
