A network prevents unauthorized users from gaining access to confidential information. The network has various workstations and servers connected by a common medium and through a router to the Internet. The network has two major components, a Network Security Center (NSC) and security network interface cards or devices. The NSC is an administrative workstation through which the network security officer manages the network as a whole as well as the individual security devices. The security devices are interposed between each of workstation, including the NSC, and the common medium and operate at a network layer (layer 3) of the protocol hierarchy. The network allows trusted users to access outside information, including the Internet, while stopping outside attackers at their point of entry. At the same time, the network limits an unauthorized insider to information defined in their particular security profile. The user may select which virtual network to access at any given time. The result is trusted access to multiple secure Virtual Private Networks (VPN), all from a single desktop machine.