Point-to-Point Tunneling Protocol (PPTP)
You can access a private network through the Internet or other public network by using a virtual private network (VPN) connection with the Point-to-Point Tunneling Protocol (PPTP).
PPTP enables the secure transfer of data from a remote computer to a private server by creating a VPN across TCP/IP-based data networks. PPTP supports on-demand, multi-protocol, virtual private networking over public networks, such as the Internet.
Developed as an extension of the Point-to-Point Protocol (PPP), PPTP adds a new level of enhanced security and multi-protocol communications over the Internet. Specifically, by using the new Extensible Authentication Protocol (EAP), data transfer through a PPTP-enabled VPN is as secure as within a single LAN at a corporate site.
PPTP tunnels, or encapsulates, IP or IPX protocols inside of PPP datagrams. This means that you can remotely run programs that are dependent upon particular network protocols. The tunnel server performs all security checks and validations, and enables data encryption, which makes it much safer to send information over non-secure networks. You can also use PPTP in private LAN-to-LAN networking.
PPTP does not require a dial-up connection. It does, however, require IP connectivity between your computer and the server. If you are directly attached to an IP LAN and can reach a server, then you can establish a PPTP tunnel across the LAN. However, if you are creating a tunnel over the Internet, and your normal Internet access is a dial-up connection to an ISP, you must dial up your Internet connection before you can establish the tunnel.