Outside access to computer resources through a firewall

Abstract

A firewall isolates computer and network resources inside the firewall from networks, computers and computer applications outside the firewall. Typically, the inside resources could be privately owned databases and local area networks (LAN's), and outside objects could include individuals and computer applications operating through public communication networks such as the Internet. Usually, a firewall allows for an inside user or object to originate connection to an outside object or network, but does not allow for connections to be generated in the reverse direction; i.e. from outside in. The disclosed invention provides a special 'tunneling' mechanism, operating on both sides of a firewall, for establishing such 'outside in' connections when they are requested by certain 'trusted' individuals or objects or applications outside the firewall. The intent here is to minimize the resources required for establishing 'tunneled' connections (connections through the firewall that are effectively requested from outside), while also minimizing the security risk involved in permitting such connections to be made at all. The mechanism includes special tunneling applications, running on interface servers inside and outside the firewall, and a special table of 'trusted sockets' created and maintained by the inside tunneling application. Entries in the trusted sockets table define objects inside the firewall consisting of special inside ports, a telecommunication protocol to be used at each port, and a host object associated with each port. Each entry is 'trusted' in the sense that it is supposedly known only by individuals authorized to have 'tunneling' access through the firewall from outside. These applications use the table to effect connections through the firewall in response to outside requests identifying valid table entries.