Network Access Control The VISION Web Site and the Distribution Support Services Web Site (the “DST Web Sites”) are protected through multiple levels of network controls. The first defense is a border router which exists at the boundary between the DST Web Sites and the Internet Service Provider. The border router provides basic protections including anti-spoofing controls. Next is a highly available pair of stateful firewalls that allow only HTTPS traffic destined to the DST Web Sites. The third network control is a highly available pair of load balancers that terminate the HTTPS connections and then forward the traffic on to one of several available web servers. In addition, a second highly available pair of stateful firewalls enforce network controls between the web servers and any back-end application servers. No Internet traffic is allowed directly to the back-end application servers. The DST Web Sites equipment is located and administered at DST’s Winchester data center. Changes to the systems residing on this computer are submitted through the DST change control process. All services and functions within the DST Web Sites are deactivated with the exception of services and functions which support the transfer of files. All ports on the DST Web Sites are disabled, except those ports required to transfer files. All “listeners,” other than listeners required for inbound connections from the load balancers, are deactivated. Directory structures are “hidden” from the user. Services which provide directory information are also deactivated.