Introducing the Windows 95 Client for Microsoft SNA Server

The Windows 95–based client is a native 32-bit software supplement to SNA Server version 2.11, an industry-leading SNA gateway product that runs on the Microsoft Windows NT Server operating system and connects PC desktops to IBM mainframes and AS/400 systems.

The Windows 95-based client for SNA Server provides a robust platform for new 32-bit 3270/5250 emulators and other SNA applications running on Windows 95 that connect to IBM hosts over a wide variety of LAN protocols and host link types.


Printing These Release Notes

To print all of the topics in this Help file, Choose the Help Topics button in this dialog box to return to the Help Topics window. Select the Contents tab, then select the Windows 95 Client for SNA Server Release Notes book icon, and choose the Print button.

To print any individual topic, click anywhere in the topic window with the right mouse button, and choose Print Topic from the pop-up menu.


Copying or Moving This File

If you want to copy or move this file to another location, be sure to copy or move both the README.CNT and README.HLP files. The .CNT file provides the Contents screen and navigation among topics.

This file can be viewed on computers running the Windows 95 or Windows NT version 3.51 operating systems.


Obtaining the Windows 95 Client for SNA Server Software

The Windows 95 Client for SNA Server files are available for downloading in a self-extracting file, named SNAWIN95.EXE. This file may be found in the following locations:

For MSN users:

    Microsoft SNA Server forum (MSSNA)

How to find the files

For CompuServe users:

    CompuServe MS WinNT SNA forum (go MSSNA)

How to find the files

For Internet World Wide Web users:

    http:\\www.microsoft.com

How to find the files

For Internet FTP users:

    ftp.microsoft.com

How to find the files

For TechNet users:

    Available on a future update

How to find the files

For MSDN users:

    Available on a future update

How to find the files


Finding the Windows 95 Client for SNA Server on MSN

From the Edit menu of The Microsoft Network screen (MSN Central), choose Go to, then choose Other Location, and type mssna

This will take you directly to the Microsoft SNA Server Forum.

From there, click the following folders:

    Microsoft SNA Server Product Information

      Technical Resources

        Windows 95 Client for SNA Server

or

From The Microsoft Network screen (MSN Central), choose the Categories button, and then click the following icons or folders:

    Computers & Software

      Computer Companies & Organizations

        Software Companies

          Microsoft

            Microsoft BackOffice & Windows NT Workstation

              Microsoft BackOffice Products

                Microsoft SNA Server Forum

                  Microsoft SNA Server Product Information

                    Technical Resources

                       Windows 95 Client for SNA Server


Finding the Windows 95 Client for SNA Server on CompuServe

Choose the GO (green light) icon, and type mssna

or

From the Services screen, choose the following folders:

    Computers/Technology

      Software Forums

        Microsoft Connection

          Support Forums and Services

            US Product Support

              Microsoft BackOffice Products

                Microsoft WinNT SNA Forum


Finding the Windows 95 Client for SNA Server on the World Wide Web
Finding the Windows 95 Client for SNA Server on the World Wide Web:

http:\\www.microsoft.com

From Microsoft’s home page, choose the following:

Products

  BackOffice

    Microsoft SNA Server

      Technical Resources


Finding the Windows 95 Client for SNA Server using FTP
Finding the Windows 95 Client for SNA Server using FTP:

ftp://ftp.microsoft.com

Note: You must have access to the internet to use FTP.

To find the files using FTP:

1.	Start FTP.

2.	Open a connection by typing:

open ftp.microsoft.com

3.	When prompted for a user name, type

anonymous

4. 	You will be prompted to type your email name for a password.

5.	To locate the file, type:

cd bussys

cd winnt

cd sna-public

dir

The SNAWIN95.EXE and README1.TXT files should be listed.

6.	To specify binary file transfer and download the files to the current directory, type

binary

get snawin95.exe

get readme1.txt

7.	To close the connection and FTP, type

bye


Finding the Windows 95 Client for SNA Server on the TechNet CD
Finding the Windows 95 Client for SNA Server on the TechNet CD:

From the Contents window, open the following books or folders:

BackOffice and Enterprise Systems

  MS BackOffice

    MS SNA Server

      Technical Notes


Finding the Windows 95 Client for SNA Server on the MSDN CD
Finding the Windows 95 Client for SNA Server on the MSDN CD:

The files will be placed on the Development Platform CD. Look for the files in the What's New folder. To display the What's New folder, open the Development Platform Installer, click on the Contents menu, and then click the List New Products option.


Operating System Considerations

The Windows 95 client for SNA Server can be installed on computers running Microsoft Windows 95 or later. For client computers running Microsoft Windows NT Workstation version 3.51 or later, you can install either the Windows 95 client or the Windows NT client (that was included with SNA Server versions 2.1 and 2.11), but not both at the same time. The Windows 95 client is supported by Microsoft SNA Server version 2.1 or later. The Windows 95 client provides full support for existing 32-bit SNA Server applications, using CPIC, APPC, LUA and FMI. Support for 16-bit SNA applications on Windows 95 is provided by the Win3x client included with SNA Server versions 2.1 and 2.11.


Licensing

Each Windows 95 SNA Client must be licensed for the server (or servers) that will be used. Licensing options include Per Seat or Per Server. For more information on licensing, see the SNA Server version 2.11 README.WRI file, Enhancements Guide, and Planning Guide.


B.   Installation


Check for Previous Versions of SNA Server Client and Remove

If you have an existing SNA Server Windows 3.x client on your computer (for instance, if you upgraded an SNA client computer running Windows 3.x to Windows), then you must first remove the Windows 3.x client by running the SNA Setup program and choosing the Remove SNA Client option.

If you are installing the Windows 95 client on a computer that already has the SNA Server Windows NT client installed, you must first run the existing SNA Setup program and remove the Windows NT client.


Download and Extract the Files

The Windows 95 Client for SNA Server can be installed from a shared network drive, or from your local drive. To install the Windows 95 client, follow these steps:

1.	Create a directory from which to install the Windows 95 client files.

Examples. To create a directory named “SNAWIN95”:

On computers running the Windows 95 operating system

On computers running the Windows NT operating system

2.	Download SNAWIN95.EXE (see “Obtaining the Windows 95 Client for SNA Server Software” for locations) to the directory created in the previous step.

Note that the .EXE file is less than 3 megabytes in size (in a compressed format).

3.	To expand the files, open a command box (MS-DOS session), change to the directory where you downloaded the SNAWIN95.EXE file, and type

snawin95.exe -d

This will expand the files for the Windows 95 Client of SNA Server into the current folder. The -d switch must be used because it enables the creation of the appropriate subdirectories. When you issue the preceding command, a message will popup to remind you to use the -d switch; it will also provide the option of cancelling the self-extraction if you did not use the -d switch.

Examples:

Expanding SNAWIN95.EXE on computers running Windows 95

Expanding SNAWIN95.EXE on computers running Windows NT


Example: To create a directory on computers running Windows 95
Example: To create a directory named “SNAWIN95” on computers running the Windows 95 operating system

On your local hard disk:

1.	Double-click the My Computer icon on your desktop.

2.	Double-click the icon representing your local hard disk.

3.	From the file menu, choose New, and then choose Folder. A new folder will be added to your root directory, with the name “New Folder.”

4.	Type a new name for the folder, for example SNAWIN95.

To share this folder so that other users can install from this location:

1.	Select the folder created in step 4 above and from the File menu, choose Properties, and then click on the Sharing tab. (If the Sharing tab is not visible, you can enable sharing by double-clicking the Network icon in the Control Panel, then choosing the File and Print Sharing button, and checking the “I want to be able to give others access to my files” box.)

2.	Select the Shared As: option button and enter a name for the sharepoint in the Share Name text entry box.

3.	Choose the Add button to add users or groups and to assign permissions.


Example: To create a directory on computers running Windows NT
Example: To create a directory named “SNAWIN95” on computers running the Windows NT operating system:

On your local hard disk:

1.	Start the File Manager program.

2.	Select the root directory of your local hard disk.

3.	From the File menu, choose Create Directory.

4.	Type a name for the directory, for example SNAWIN95.

To share this directory so that other users can install from this location:

1.	Select the directory created in step 4 above and from the Disk menu, choose Share As.

2.	Enter a name for the sharepoint in the Share Name text entry box.

3.	Choose the Permissions button to add users or groups and to assign permissions.


Expanding SNAWIN95.EXE on computers running Windows 95

1.	From the Start menu of Windows 95, choose Programs, and then click the MS-DOS Prompt folder. An MS-DOS Prompt command box appears. (Note: This is the COMMAND.EXE program.)

2.	In the MS-DOS Command box, type

CD \folder

where folder is the name of the folder where the SNAWIN95.EXE file is located.

3.	Next, type

snawin95.exe -d


Expanding SNAWIN95.EXE on computers running Windows NT

1.	From Program Manager, double-click on the MS-DOS icon. An MS-DOS Prompt command box appears. (Note: This is the CMD.EXE program.)

2.	In the command box, type

CD \directory

where directory is the name of the directory where the SNAWIN95.EXE file is located.

3.	Next, type

snawin95.exe -d


Run the Setup Program to Install the Files

1.	Connect to the network share or the local directory where the SNAWIN95.EXE file was extracted, and run the Setup program (SETUP.EXE).

2.	During setup you will be prompted for a directory name (SNA95 is the default name). If you have extracted the SNAWIN95.EXE file to your local drive and you want to install the program to the same drive, you must specify a different directory than the one you are running the Setup program from.


Choices During Setup

The following choices will be available during installation:

•	Installation Path. Choose the installation path for the files (C:\SNA95 is the default).

•	Complete or Custom Installation. Choose Complete to install all components. Choose Customized to install the minimum number of files needed plus any custom components which are selected.

•	Choose Program Group. Choose the Program Group or Folder that the icons for the SNA Client will be copied into (SNA Client for Windows 95 is the default).

•	Licensing Agreement.

•	Client/Server Protocol. Contrary to the documentation for SNA Server version 2.11, you may choose only one client protocol; however, the protocol can be reconfigured at any time after installation, through the new Configuration program included with this client software.

•	Client Mode. Choose Local (for a client in the same network domain or SNA Server subdomain as the server) or Remote.

Contact your SNA Server administrator if you need assistance with these choices.


C.   Starting and Stopping the Windows 95 Client for SNA Server


Starting the Windows 95 Client for SNA Server

To start the client, choose the SNA Client for Windows 95 folder from the Programs folder of the Start menu. From this group, choose the program item that you want to run to make a client connection to a computer running SNA Server. The SnaBase program (SNABASE.EXE) will be started.


Stopping the Windows 95 Client for SNA Server

The SnaBase program (SNABASE.EXE) is started when you start a program that establishes a connection with a computer running SNA Server. The SNA Client will remain running until you shut down or restart Windows 95, unless you enable AutoTerminate. AutoTerminate is enabled by selecting the Terminate SNA Client on Disconnect check box in the Advanced tab of the SNA Client Configuration dialog box.

To manually stop the SnaBase program, right-click (that is, use the right mouse button) with the mouse pointer on the SnaServer icon in the taskbar or taskbar notification area. Choose Close from the menu that appears.


Removing the Windows 95 Client for SNA Server by Using Setup

If you attempt to run the SNA Setup program while SNA Client or any other SNA component is running, an error message will appear. Close all SNA components and rerun Setup to remove the Windows 95 Client for SNA Server.

The Setup program may not be able to remove all files from the SNARoot directory where the client files were installed. Any files not removed by the Setup program can be manually deleted.


Removing the Windows 95 Client for SNA Server Without Using Setup

If you want to uninstall the Windows 95 Client for SNA Server without using Setup, do the following:

1.	Go into the registry editor (in Windows 95: from the Start menu, choose Run, and type regedit in the Open text entry option; in Windows NT: from the Run menu of the Program Manager, type regedt32) and remove the following keys:

HKEY_LOCAL_MACHINE

SOFTWARE

Microsoft

      SNA Server

HKEY_LOCAL_MACHINE

SOFTWARE

Microsoft

      SnaBase

Click the Help in the Registry Editor dialog box for more information on editing the registry.

Changes to the registry should be made with caution.

2.	Delete the entire directory and its contents where the client was installed.

3.	Remove the Program Group and all icons that were created by the Setup program. (From the Windows 95 Start menu, choose the following buttons: Settings, Taskbar, Start Menu Programs, Remove. Select the folder containing the SNA Client for Windows 95 icons on the program menu listed in the Remove Shortcuts/Folders dialog box. Choose the Remove button.)


D.   New Features


Change Configuration Without Running Setup

Configuration options can now be changed without running the Setup program. The following options can be changed:

•	Network domain or SNA Server subdomain

•	Client mode (local or remote)

•	Sponsors (primary and backup SNA servers)

•	Transport protocol

•	Show Icon on task bar and Restart SNA Client options

•	Use Windows NT domain password or specify Logon Domain options

•	AutoTerminate with timeout value

For more information on these options, see the context-sensitive Help by clicking the question-mark icon in the upper right corner of the dialog box and then selecting the option (or right-clicking and selecting What’s This?).

To review or change the configuration settings, open the SNA Client Config folder in the SNA Client for Windows 95 folder. The SNA Client Configuration dialog box will appear.

Optionally, if the SnaBase program (SNABASE.EXE) has been started, you can access the SNA Client Configuration dialog box by right-clicking the SnaServer icon on the taskbar or the small icon on the taskbar notification area, and then selecting Config from the menu. The SNA Client Configuration dialog box can also be accessed by double-clicking (with the left mouse button) the SnaServer small icon in the taskbar notification area. The SnaServer icon appears in the Windows 95 taskbar if the Show Icon on task bar option on the Config tab of the SNA Client Configuration dialog box is checked. If this option is not checked, the SnaServer small icon appears on the Windows 95 taskbar notification area (to the far right of the taskbar).

On Windows NT version 3.51 there is no taskbar and the Show Icon on task bar option is always checked (the check box is also disabled).

When SNABASE.EXE fails to open its sponsor connection, it displays the SNA Client Configuration dialog box and it also automatically checks the Restart SNA Client check box.


3270 and 5250 Applets

The Windows 95 client for SNA Server includes single-session 3270 and 5250 emulation applets, which are intended for evaluation and support purposes only (the applets are licensed for one user per SNA Server—full-function emulators are available from ISVs). The applets are native 32-bit emulators; they can be used to evaluate the full functionality of SNA Server version 2.11, which includes support for native TCP/IP, IPX, and dial-up connections between Windows 95 and SNA Server, integrated security with Windows NT Server, as well as load balancing and hot backup.

Select the SNA Client 3270 Applet or the SNA Client 5250 Applet icon from the SNA Client for Windows 95 program group to start.


ODBC/DRDA Driver

The Windows 95 client for SNA Server includes an ODBC driver for access to IBM DB2 databases, such as DB2 for MVS and DB2/400, by using the Distributed Relational Database Architecture (DRDA) protocol. The ODBC driver is compatible with Microsoft Office for Windows 95 and allows applications such as Microsoft Excel to access data on the host databases without additional host software. This ODBC driver, developed for Microsoft by StarWare Inc., is licensed for one user per SNA Server. Additional licenses are available from StarWare.

For more information on using the ODBC driver, see the Microsoft SNA Server Enhancements Guide.


AFTP File Transfer Utility

APPC File Transfer Protocol (AFTP) is an IBM-developed protocol that duplicates for the SNA environment the function of the popular FTP utility in the TCP/IP environment. IBM is offering the host component of AFTP at a nominal cost for most of the IBM host operating systems. With the AFTP utility, customers can perform multi-megabyte file transfers between the host and the Windows 95–based system quickly by using native SNA protocols, eliminating the need to install an expensive and CPU-intensive TCP/IP stack on the host in order to perform FTP file transfers.

Select the SNA Client AFTP icon from the SNA Client for Windows 95 program group to start.

For more information on using the SNA Client AFTP, see the Microsoft SNA Server Enhancements Guide.


APPC, CPI-C, and LUA APIs

To facilitate development of new 32-bit Windows-based SNA applications, the Windows 95 client for SNA Server includes a full set of 32-bit SNA APIs. APPC and CPI-C APIs can be used to develop applications which use the LU6.2 protocol to access other APPC or CPI-C applications on the IBM host systems, or to develop 5250 emulators and other AS/400 access utilities. The LUA API is available for development of LU0-based banking applications for access to existing IMS data; to develop 3270 emulators; or to gain programmatic access to the LU1, LU2, and LU3 data streams. The APIs are compatible with the WOSA SNA API standard; they are also binary compatible with the SNA APIs for Windows NT, as supported by the current SNA Server version 2.11.


Dynamic Tracing Utility

The graphical tracing utility included with the Windows 95 client for SNA Server provides for easy diagnosis of connectivity problems. Tracing can be enabled and disabled dynamically without stopping running programs. The same utility can be used by developers to step through the SNA API calls in their own programs.

To review or change the tracing settings, open the SNA Client Trace folder in the SNA Client for Windows 95 folder.

Optionally, if the SnaBase program has been started, you can right-click the SnaServer icon in the taskbar or taskbar notification area and choose the Trace option.

For more information on trace options, choose the Help button in the SNA Server Trace Options dialog box or see Chapter 13 of the Microsoft SNA Server Administration Guide.


Context-Sensitive Help

Context-sensitive Help is now available on most dialog boxes through a question-mark button in the upper right corner of the dialog box. To view Help for a dialog box, click the question-mark button, then move the cursor (which acquires a question mark) over the term in question and click the mouse again.

Context-sensitive Help can also be viewed by right-clicking on an item and then selecting What's This? from the pop-up menu.


E.   Differences in Operation With SNA Server Versions 2.1 and 2.11


Security Considerations

There is a setting called “Use Windows NT domain password” in the Advanced tab of the SNA Client Configuration dialog box. This setting controls security.

When connecting to computers running SNA Server version 2.11, the Windows 95 Client for SNA Server can use the Windows NT domain name and password (that you logged in as) to provide security information to SNA Server. This is enabled by default.

If you want to communicate with SNA Server version 2.11 servers without logging into Windows NT domain, or if you are connecting to SNA Server version 2.1 servers, you should clear the “Use Windows NT domain password” check box for the Windows 95 SNA Client. If this is check box is cleared, you can enter the name of a logon domain in the Logon Domain text box. When connecting to a server, you will be prompted for a password.

To review or change the Security setting, open the SNA Client Config folder in the SNA Client for Windows 95 folder. The SNA Client Configuration dialog box will appear. Choose the Advanced tab.

Optionally, if the SnaBase program has been started, you can double-click SNA Server on the taskbar or the SNA Server icon in the taskbar notification area to access the SNA Client Configuration dialog box.


F.   Additional Notes


Choosing a Transport Protocol for Best Performance

The initial release of the Windows 95 SNA client supports Named Pipes, Windows Sockets over TCP/IP and Windows Sockets over SPX/IPX. A Banyan VINES IP transport will be made available shortly after a VINES protocol stack for Windows 95 is available.

Although Named Pipes can be used over NetBEUI, TCP/IP, and SPX/IPX, best performance can be achieved by using the native IP mechanism for the underlying protocol stack. If your machine is using TCP/IP or SPX/IPX to communicate with SNA Server, best performance will be achieved by selecting the appropriate Windows Sockets transport. If you are using NetBEUI, you must select Named Pipes.

For more information on client/server communication, see Appendix A of the Microsoft SNA Server Planning Guide.


Optimizing Microsoft SNA Client Performance on TCP/IP Networks

Performance of the Microsoft SNA Client can be optimized on TCP/IP networks by disabling the Nagle algorithm on the SNA Clients and Server(s). The Nagle algorithm is used to reduce the number of small packets sent by a host by buffering unacknowledged send data until a full-size packet can be sent. This reduces the number of small writes that are sent across the network and has the effect of reducing network activity at the expense of increasing the time taken to send small writes across the network.

For optimal TCP/IP performance across LANs, the Windows 95 client by default disables the Nagle algorithm, causing small writes to be sent across the network immediately. For best performance, the Nagle algorithm should also be disabled for the SNA Server machines that the Windows 95 client will connect to.

To disable the Nagle algorithm on the Windows NT SNA Servers, add the following Key to the Windows NT registry:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SnaBase\SnaTcp

and below this key, the value

NoDelay, REG_SZ, "YES"

In some situations, it may be preferable to enable the Nagle algorithm on the Windows 95 client. This might be done in the case of clients communicating with SNA Servers across a wide area network using slow connections. To enable the Nagle algorithm on the Windows 95 client, add the following key to the registry:

HKEY_LOCAL_MACHINE\Software\Microsoft\SnaBase\SnaTcp

and below this key, the value

NoDelay, REG_SZ, "NO"


TP Issues

The Windows 95 client cannot run transaction programs (TPs) implemented as Windows NT services. Autostarted invokable TPs must be set up as application TPs in the registry. For more information on TPs, see the Microsoft SNA Server documentation.


Note on Using TCP/IP Transport for SNA Client on Systems With Windows 95 Plus! Pack and Internet Access Installed

If you install dial-up access to the Internet from the Windows 95 Plus! pack, you get a utility that automatically dials your Internet provider whenever an application requests a TCP/IP session. If your system connects to the SNA Server via TCP/IP over a LAN connection rather than the dialed Internet connection, you will see a pop-up message from the dialer every time you use the SNA Client, just as you do for any other TCP/IP application that connects over the LAN.

To disable the automatic display of the dialer pop-up message, open the Control Panel, select the Internet icon, and clear the Use AutoDial check box in the AutoDial tab of the Internet Properties dialog box.


Information on Microsoft SNA Server

For important information about Microsoft SNA Server version 2.11, see the documents in the printed document set, or on the SNA Server CD-ROM in the \DOCS directory. Each of the documents in the SNA Server document set is available in three file formats: as Microsoft Word for Windows version 2.0 document files, as PostScript files (for printing), and as online Help files.

For information about the location of particular document files, see the README.TXT file in the \DOCS directory on the CD-ROM.  The README.TXT file in the \DOCS directory also tells how to print the documents.

For supplementary information and corrections to the SNA Server documentation, see the README.WRI file in the root directory of the Microsoft SNA Server version 2.11 CD-ROM.


H.   Troubleshooting


Problems With Setup

If you experience difficulties when running the Setup program, use the following guidelines to diagnose and remedy the problem.

Problem	Explanation	Solution
Setup does not install the program.	Setup will not install this program if an existing version of an SNA Server client resides on the drive.	Close all SNA components. Run Setup and choose the Remove All option to remove the previous version.
Setup does not remove the previous version.	Setup cannot remove the previous version if any SNA components are running.	Close all SNA components.
Setup removes some files, but is unable to complete.	Setup may remove some files, but will not be able to complete the process if an SNA component is running. This can result in incomplete removal of the files and the registry entries.	See “Uninstall Without Using Setup” under the “Starting and Stopping the Windows 95 Client for SNA Server” book icon in this help file.


Problems Running Windows 3.x Client Software on Windows 95

Summary

The SNA Server Windows 3.x client software is supported by Windows 95. However, if the SNA Server client software is configured to use the “Microsoft Networking (Named Pipes)” interface and Windows 95 is configured with Microsoft IPX/SPX-compatible protocol (the default), starting an SNA Server Windows 3.x client application will cause Windows 95 to stop responding, with an hourglass icon showing indefinitely.

At this point, the user must enter CTRL+ALT+DEL to bring up the Windows 95 Close Program dialog box, select the task named "SNA Server (Not responding)," choose "End Task," and confirm the selection by choosing "End Task" again.  This will cause the Windows 95 hourglass to disappear (the SNA Server Windows 3.x client process -- WNAP.EXE -- will then be stopped).  After this, the SNA Server Windows 3.x application can be stopped using the "End Task" option.

Any one of the following solutions can be used to work around the preceding problem:

•	If you want to keep the Microsoft IPX/SPX Compatible protocol installed, the IPX/SPX NetBIOS interface must be enabled and the DirectHost feature must be disabled (see How To Enable IPX/SPX NetBIOS and Disable Directhost for instructions).

•	Keep the SNA Server Named Pipes interface enabled, remove the Microsoft IPX/SPX-compatible transport, and install a different Microsoft transport (such as NetBEUI or TCP/IP) by using the Windows 95 network control panel.

•	Configure the SNA Server Windows 3.x client software to use an interface other than named pipes, by running the SNA Server client Setup program installed in the SNA Server client program group.

Cause

When the SNA Server Windows 3.x client software is configured to use the named pipes interface, the SNA Server client software always posts a DosReadAsyncNmPipe API call on the named pipe.  This causes a Read request to always be posted to the server.  While the Read request is outstanding, the SNA client software also may write data down the named pipe as well, so the SNA client makes use of the full-duplex nature of the named pipe API, supported over any LAN protocol provided by Windows 95 (i.e. NetBEUI, IPX/SPX, TCP/IP, RAS, and so on).

However, if the Microsoft IPX/SPX-compatible transport is installed and the DirectHost feature is enabled on Windows 95, this network interface allows only a single command to be outstanding on the client/server LAN session (that is, this only provides a half-duplex communication channel to the server).  So, the SNA Server client named pipe interface will not work properly.

In contrast, Windows 95 file and print redirection and SQL Server named pipe clients do work over DirectHost IPX/SPX connections because only a single command is outstanding at one time (that is, the DosReadAsyncNmPipe call is not used).


How To Enable IPX/SPX NetBIOS and Disable Directhost

To enable the NWLINK NetBIOS interface:

1. Click the Start button, point to Settings, and click Control Panel.

   The Control Panel folder opens.

2. Double-click Network.

   The Network dialog box appears.

3. Select IPX/SPX-Compatible Protocol Properties, then choose the

   Properties button. The IPX/SPX-Compatible Protocol Properties dialog box appears.

4. Choose (check) the I Want To Enable NetBIOS Over IPX/SPX check box,

   and choose OK.

To make this change take effect, you must restart Windows 95.

To disable the IPX/SPX DirectHost feature:

1. Click the Start button, then click Run.

   The Run dialog box appears.

2. Type regedit and choose OK.

   Registry Editor starts.

3. Open (click on the plus symbol next to) HKEY_LOCAL_MACHINE, then open System,

   CurrentControlSet, Services, and then finally open Vxd.

4. Select VNETSUP.

5. From the Edit menu, select New, then choose String Value.

   A new value appears in the right pane.

6. If necessary, right-click the new item and choose Rename from

   the context menu. Type DirectHost and press ENTER.

7. Right-click DirectHost and choose Modify.

   The Edit String dialog box appears.

8. Type 0 (zero) and choose OK.

9. Click Registry, then click Exit to end the Registry Editor.

This change will take effect when you next start Windows 95.