Virtual Private Network (5)
A VPN can be used in place of traditional dial-up connections to provide access to remote users and telecommuters; can be used to connect LANs in different sites instead of using the public switched telephone network or dedicated leased lines; and can be used to give customers, clients and consultants access to corporate resources.
Most VPNs can be designed to work as an extranet. But not all extranets are VPNs. A VPN can be used in a similar manner, but typically a VPN has much higher security associated with it. Specifically, a VPN typically requires the establishment of a tunnel into the corporate network and the encryption of data passed between the user's PC and corporate servers.