Configuring the server
Depending on which version of Windows you have, you may need to make some changes on the server.
Disable the Windows firewall for you network connections.
The built-in Windows firewall (as well as some third-party ones) causes problems if it's running on the server, but I had no problem with it on the client PCs.
Edit registry key value:
Routing registry key.reg (right-click, save, and run)
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters IPEnableRouter = dword:00000001
This registry key will enable the routing set in the config file to work correctly.
WINDOWS 2000 SERVER
For routing to work properly on W2K server I had to enable and configure some settings in Routing and Remote Access.
To do this, go to Control Panel→ Admin tools -> Routing and remote access.
Right-click on the computer name and then select Configure and enable Routing and remote access.
Now select Internet Connection Server.
Now select"Set up a router with the Network Address Translation (NAT) routing protocol," then highlight the real network interface connected to the router when prompted. Next, use the selected Internet connection.
Now highlight the TAP-Win32 Adapter V8 when prompted. Select the routing interface for the network that should have access to the internet.
This should take care of the routing on your server.