WindowsXP VPN Server
The following page details the steps necessary to create a WindowsXP VPN Server
1.	Go to Start / Settings / Network Connections
2.	Start the New Connection Wizard
3.	Click on the Next button
4.	Select Set up advanced connection
5.	Click on the Next button.
6.	Click on Accept incoming connections
7.	Click on the Next button
8.	At the LPT1 page, skip it and just click on the Next button.
9.	Click on Allow virtual private connection
10.	Click on the Next button
11.	Add user accounts that you want to be able to connect to your WindowsXP computer.
12.	Click on the Next button.
13.	Highlight Internet Protocol (TCP/IP) and click on Properties
14.	Determine how you want the remote computers to get their IP address
19.	The above example will assign IP addresses to each client. Make sure the IP scheme is the same as on your server.
20.	Submitted by Andy Bloss If the VPN server is behind a router, Port Mapping will need to be done on the router. Standard port usage is 1723 for PPTP. You might also need to configure your router for PPTP Passthrough. Port usage for IPSec is 500, 50-51. These ports will have to be forwarded to the VPN server's IP

Installing a VPN client in Windows XP

To let a client connect to your VPN server, you need to define all the connection settings (server address, protocols to be used, etc.) The new connection wizard available from the Network connections icon in the control panel enables this configuration:

Then click Next:

Out of the three choices offered in the window, select "Connect to the network at my workplace":

On the next screen select "Virtual private network connection":

Then enter a name that best describes the name of the virtual private network you want to connect to:

The next screen lets you determine whether a connection needs to be established before connecting to the virtual private network. Most of the time (if you are on a permanent connection or ADSL or cable access), it will not be necessary to establish the connection since the computer is already connected to the Internet; if this is not the case select the connection to be established from the list:

To access the remote access server (VPN server or host), you must specify its address (IP address or host name). If it does not have an IP address, you will need to equip it with a dynamic naming system (DynDNS) capable of assigning it a domain name and specify this name in the following field:

Once you have finished defining the VPN connection, a connection window opens asking you for a login and password:

Before connecting, you need to define some settings by clicking the Properties button at the bottom of the window. A window featuring a certain number of tabs then lets you more narrowly configure the connection. In the Network management tab, select the PPTP protocol from the scrollable list; select the (TCP/IP) Internet protocol and click Properties:

The window that appears lets you define the IP address the client machine will have when connecting to the remote access server. This lets you have addressing that is consistent with the remote addressing. As such, the VPN server is capable of acting as a DHCP server, that is, of automatically providing the VPN client with a valid address. To do so, simply select the "Obtain an address automatically" option:

In the event that the client uses the DHCP, if the server assigns an internal IP address, the client will be connected to the workplace network and will benefit from its services but will no longer have Internet access via the interface used since the IP address is not routable. In order to let the client be connected to the VPN and still have Internet access via this connection, the VPN server must be configured such that it shares its connection! The Advanced button lets the client use the VPN server's gateway in the event that the latter shares it connection:

To be able to set up the VPN connection, intermediary firewalls, and particularly XP's native firewall, need to be configured to let the connection be established. You therefore need to disable Windows XP's native firewall by doing the following: In the control panel click Network connections, Right-click the connection you use, Select the Advanced settings tab, Make sure the Internet connection firewall option is disabled.