Web Publishing Rules
ISA Server uses Web publishing rules to relieve the concerns associated with publishing Web content without compromising network security. Web publishing rules determine how ISA Server will intercept incoming requests for HTTP objects on a Web server, and how ISA Server will respond on behalf of the Web server. Requests are forwarded to the Web server, located behind the ISA Server computer. If possible, the request is serviced from the ISA Server cache.
Web publishing rules essentially map incoming requests to the appropriate Web servers. Web publishing rules also enable you to configure advanced filtering functionality, thereby publicizing your Web-based information while securing it from malicious access.