Abstract: A secure interface between a private network and a public network are disclosed. The interface includes a collection of routing devices, telecommunications devices, packet-filtering devices, applications-filtering devices, monitoring and maintenance devices organized to enforce a wide variety of desired customer security policies. The apparatus allows a central service provider to install and maintain a collection of similar apparatus and support a number of customers with widely varying security policies and allows a rapid change in the security policy of a given customer, without affecting the security of other customers, and without requiring the customer to understand or modify the underlying apparatus.