WFW 3.11 Fails to Connect to SNA Server on Windows NT 3.5

• Microsoft Windows NT Workstation versions 3.5 and 3.51
• Microsoft Windows NT Server versions 3.5 and 3.51
• Microsoft SNA Server for Windows NT, versions 2.0, 2.1, and 2.11

SYMPTOMS

After upgrading an SNA Server computer from Microsoft Windows NT version 3.1 to Windows NT version 3.5 or 3.51, Microsoft Windows for Workgroups version 3.11 client computers fail to connect to SNA Server:

   SNA Server Error: 546
   Cannot establish connection with SNA Server <server name>.

CAUSE

The Microsoft IPX/SPX compatible transport (NWLink) is installed by default with Microsoft Windows for Workgroups 3.11. When you configure the SNA Server client to use the "MS Network Client (named pipes)" interface, the NWLink transport is automatically used. This works fine with a Windows NT 3.1 server.

Under Windows NT 3.5, a new feature, direct hosting, was added to improve performance. This allows a Windows for Workgroups client to communicate directly with the server over IPX/SPX, rather than over NetBIOS. However, applications which use named pipes do not work correctly over direct-hosted IPX/SPX connections.

WORKAROUND

To resolve this problem, add the following entry to the [network] section of SYSTEM.INI on the Windows for Workgroups 3.11 client computer:

   [network]
   DirectHost=NO

Microsoft provides updated Windows for Workgroups 3.11 client modules on the Windows NT 3.5 CD-ROM, though the updated modules do not solve the direct hosting problem. However, other named pipes applications (such as SQL Server) work fine with these updates.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 3.5. We are researching this problem and will post new information here as it becomes available.