How to configure Win 2000/XP Pro as VPN host
Prior to Windows 2000/XP Pro, you must add PPTP on NT 4.0 Server to establish VPN connections. With the release of Windows 2000/XP Pro, you have the ability to run a Windows 2000/XP Pro as a VPN host. However, Windows 2000/XP Pro enables only one VPN connection at a time and requires Internet Protocol (IP).
Before you start the VPN configuration, you should have a equipment (modem, T1, Frame Relay, ADSL, or cable modem) connecting to the Internet. Also make sure you have correct TCP/IP settings on the W2K/XP.
To setup Win XP (in our case) Pro as VPN host, go to the Properties of My Network Places>Create a New Connections>Set up a Advanced Connection>Accept Incoming Connections. On the Devices for Incoming Connections dialog box, do not select any device, only click Next and check Allow Private Connections, and then click Next. On the Allowed Users dialog box, select or add all users for whom you want to enable access. The accounts have to exist on both computers that are involved in establishing the VPN connection. On the New Connection Wizard, File and Printer Sharing for Microsoft Networks, Internet Protocol (TCP/IP) and Client for Microsoft Networks should be listed as networking components. By default, Allow callers to access my local area network and Assign TCP/IP address automatically using DHCP are checked. If you would like to keep the default settings, click Next to continue. Now, the Incoming Connection icon should show on Incoming section under the Properties of My Network Places and is ready to use.
How to configure a W2K/XP as VPN client
To connect to a VPN server, you should have a dail-in modem or a dedicated connection to the Internet. To setup a XP client to access the VPN host, go to the Properties of My Network Places>Create a New Connections>Connect to the network at my workplace>Virtual Private Network connection. Type Computer that will be showed as connection name in VPN section, select Do not dial the initial connection and then type the VPN host IP. You have two options to create this connection for anyone or for yourself.
source:
http://www.chicagotech.net/vpnsetup.htm
