WFWSYS.CFG Remote Update from Windows NT 3.5 Fails

• Microsoft Windows NT Workstation version 3.5
• Microsoft Windows NT Server version 3.5
• Microsoft Windows for Workgroups version 3.11

Windows for Workgroups 3.11 clients use a null session to remotely update the local WFWSYS.CFG security file. Windows NT 3.1 supports null sessions by default. However, Windows NT 3.5 does not provide this support unless specifically configured to do so. This change was made to provide a higher default level of security.

Thus, when you try to remotely update WFWSYS.CFG from Windows NT 3.5, it fails. If you use the Windows for Workgroups 3.11 ADMINCFG.EXE utility to update Windows for Workgroups 3.11 clients remotely, it will fail if the Update Security Configuration from Server check box is selected and the Network Path is directed to a share on a Windows NT 3.5 computer.

To enable remote updating of WFWSYS.CFG from Windows NT 3.5, null session support must be configured on a per-share basis as follows:

WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

1. Start Registry Editor.

2. In the HKEY_LOCAL_MACHINE subtree, locate the following subkey:

         \System\CurrentControlSet\Services\LanmanServer\Parameters
   

3. Choose the NullSessionShares value.

4. On a new line, type in the share name you want NULL sessions to succeed to (for example, PUBLIC).

5. Stop and restart the server.