High-assurance file-driven content filtering for secure network server

A server for transferring data between networks. The server is programmed to perform the following steps: (a) creating a receiving process, a filtering process and a forwarding process, the filtering process being dictated by a file that specifies filtering rules, wherein: (b) the receiving process receives data transmitted from a source host; (c) the filtering process filters the transmitted data based on the filtering rules; and (d) the forwarding process forwards only filtered data to a destination host.