(第4空)VPN connections allow users working at home or on the road to connect in a secure fashion to a ( ) corporate server using the routing infrastructure provided by a public internetwork (such as the Internet). From the user's perspective, the VPN connection is a point-to-point connection between the user's computer and a corporate ( ). The nature of the ( ) internetwork is irrelevant to the user because it appears as if the data is being sent over a dedicated ( ) link. VPN technology also allows a corporation to connect to branch offices or to other companies over a public internetwork, while maintaining secure ( ). The VPN connection across the Internet logically operates as a wide area network link between the sites.