tunnel

Relative to the Internet, tunneling is using the Internet as part of a private secure network. The tunnel is the particular path that a given company message or file might travel through the Internet.

A protocol or set of communication rules called Point-to-Point Tunneling Protocol (PPTP) has been proposed that would make it possible to create a virtual private network through tunnels over the Internet. This would mean that companies would no longer need their own leased lines for wide-area communication but could securely use the public networks.

PPTP, sponsored by Microsoft and other companies, and Layer 2 Forwarding, proposed by Cisco Systems, are among the main proposals for a new Internet Engineering Task Force (IETF) standard. With PPTP, which is an extension of the Internet's Point-to-Point Protocol (PPP), any user of a PC with PPP client support will be able to use an independent service provider (ISP) to connect securely to a server elsewhere in the user's company.