This Microsoft® Windows® Sockets 2 release is an update of the Windows Sockets 2 version released as a Software Developers Kit (SDK) version only. This release includes a new version of the TCP/IP stack and resolves the following Winsock issues:

• Slow performance with some IPX applications
• An incompatibility with Microsoft Internet Explorer 4.0 that could cause a page fault
• IGMP V2 support had a problem that meant that applications could drop out of a multicast group

CONTENTS
This update consists of one file WS2SETUP.EXE. This file installs an updated TCP/IP stack, updated TCP/IP utilities and updated Winsock2 components.

SETUP WINDOWS 95 RUN-TIME COMPONENTS
WS2SETUP.EXE detects versions of Windows newer and older than Windows 95 and will NOT install over them. WS2SETUP.EXE will, by default, install the Microsoft service providers and TCP/IP stack upgrade unless explicitly instructed not to do so when it attempts to call a vendor installation DLL.

If WS2SETUP.EXE determines that there are non-Microsoft WinSock 1.1 system DLLs present, installation will terminate unless specific override instructions configured by the vendor's installation dll are determined to exist.

If WS2SETUP.EXE finds that there is at least one Winsock2 compatible service provider installed, it will backup the current installation and proceed to copy the WinSock2 DLLs into the correct directories and configure the registry. It is necessary to reboot before using WinSock2.

WS2SETUP.EXE has been tested on Windows 95 and Windows 95 OEM Service Release 2 machines that have the Microsoft TCP/IP and IPX stacks (for WinSock 1.1) already installed and on machines that have either no TCP/IP and/or no IPX installed. Microsoft recognizes that there are other network transport stacks present in the industry, but this setup program does not upgrade them.

Warning: Neither WS2SETUP.EXE, nor any of the separate WinSock2 DLLs, should be installed on Microsoft Windows NT®. WinSock2 is built into Windows NT version 4, and will not be provided for earlier versions of Windows NT.

WS2SETUP.EXE AND MICROSOFT PROXY SERVER WINSOCK PROXY CLIENT
If WS2SETUP.EXE detects that the existing wsock32.dll is from the Microsoft Proxy Server WinSock Proxy Client (by way of the strings "Microsoft" &"Proxy" appearing in the version copyright), setup will look for the file _MSRWS32.dll, and perform a pass of its copyright version checking (as defined in section above) on _MSRWS32.dll as it did on WSOCK32.DLL. Setup will continue on, or abort depending on the copyright string as it normally would.

If WS2SETUP.EXE validates _MSRWS32.dll's copyright string, it will continue to install Winsock2 and the Microsoft Proxy Server Remote WinSock Client will work as it did prior to upgrade.

WS2Setup.exe INSTALLS NEW VERSION OF NDIS.VXD
Setup.exe will install a version of NDIS.VXD which is newer than that which came with the original Windows 95 release (ver 4.00.950) when either the Microsoft TCP/IP or IPX stack is included in the installation. The only known problem with the new NDIS.VXD involves the miniport MDGMPORT.SYS for Madge Smart Token Ring Adapters, shipped with Windows 95. If you have one of these cards or experience any other difficulties, please remove this driver and reinstall using the latest driver (v2.11 or later) or contact Madge customer support. If your Windows 95 version is 4.00.1111 or higher, there is no difference between the new NDIS.vxd and your existing one.

WS2SETUP.EXE AND DCOM'95
WS2SETUP.EXE will only install on machines that have DCOM'95 build 812 or higher, or no version of DCOM'95 at all. If a version of DCOM'95 prior to build 812 is detected, WS2SETUP.EXE will abort without installing Winsock2 for Windows 95 and an error message will be written to WS2SETUP.LOG.

To obtain an updated version of DCOM'95, see http://www.microsoft.com/com/dcom95/download-f.htm for availability, download instructions and release notes.

WS2SETUP.EXE AND DUN 1.2
If you need to install the Dial-Up Networking 1.2b or earlier update, install the Winsock2 upgrade after installing the Dial-Up Networking upgrade. Due to a problem in the Dial-Up Networking upgrade it will overwrite some more recent files from the Winsock2 upgrade.

WS2SETUP.EXE AND BETA VERSIONS OF THE WINSOCK2 FOR WINDOWS 95
If you are currently using a beta version of the Winsock2 for Windows 95 executables, you should completely uninstall that version to return to your pre-existing WinSock 1.1 configuration prior to running WS2SETUP.EXE.

To remove the older version, follow the directions in the section below called "Unistalling Winsock2". You will also need to delete the directory C:\\WS2BAKUP and its contents manually to assure that all traces of the beta(s) are removed.

Note: It may also be necessary to reinstall TCP/IP from the Control Panel prior to running WS2SETUP.EXE, sincenewer versions of the beta do not contain replacements for the TCP/IP utilities, while older versions do. The final release makes use of the original Windows 95 TCP/IP utilities.

UNINSTALLING WINSOCK2
When WS2SETUP.EXE runs for the first time, it copies WS2BAKUP.BAT and the WinSock 1.1 files to %windir%\ws2bakup.

Running WS2BAKUP.BAT returns the user to their original WinSock 1.1 configuration. From Windows Explorer, simply double click on "C:\\WS2BAKUP\ws2bakup.bat to uninstall Winsock2.

Caution: When you run WS2BAKUP.BAT from inside Windows 95, you may encounter a sharing violation as some system files may not be restored if the newer version is currently running! If this happens, you will need to re-run WSBAKUP.BAT in MS-DOS® mode. To do this click "Start", "Shut Down", select the "Restart the computer in MS-DOS mode" option, and click "OK". After reboot you will need to type "C:\\WS2BAKUP\WS2BAKUP" and hit the Enter key. (In MS-DOS mode you will see errors for programs that cannot run outside of Windows, but you should not be concerned, as these programs will have already executed properly if you ran WS2BAKUP.BAT from inside Windows 95 first.) Reboot again and you will be back on WinSock 1.1

Note that if you are reinstalling WS2SETUP over a previous version of Winsock2 greater than beta 2, your prior configuration will NOT be backed up again. Uninstalling will yield your original 1.1 configuration, NOT beta 2 or 2a.

DO NOT restore by re-installing TCP/IP from the Network applet in the Control Panel! This action will NOT replace the WinSock DLLs, and does not guarantee you will have the same configuration you had before upgrading to Winsock2

NEW TCP/IP FEATURES
This release of Windows Sockets 2 for Windows 95 Microsoft TCP/IP includes several features that improve network performance. These features include large windows, selective acknowledgements, fast retransmission and recovery. In addition the DHCP client supports DHCP release on shutdown and DHCP decline, and WINS servers can now be set per adapter.

NOT IMPLEMENTED
The following features are available in the Windows Sockets 2 DLL, as per the specification, but they are either not implemented or not yet well tested in the Microsoft TCP/IP service provider.

• Generic QoS
• Socket Groups--these have been removed from the Winsock2 specification
• Deferred Accept
• Disconnect/Connect Data