PRB: "TDS buffer length too large" Error with SQL Server

The information in this article applies to:

• Microsoft Visual FoxPro for Windows, version 3.0

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:

   [Microsoft][ODBC SQL Server Driver]TDS buffer length too large(#0)

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

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.