If you use Microsoft`s built-in VPN with the PPTP protocol you probably experience occasional problems where the VPN stops working. You need TunnelRat. TunnelRat installs and runs in the tray area of your Windows XP system. It sends a packet through your VPN tunnel periodically. If the packet does not transmit sucessfully, TunnelRat will stop and restart your VPN. Detects problems other than simple dropped connection. Very simple to install.