|Microsoft Internet Security and Acceleration Server 2004 SDK|
Web (ISAPI) filters detect and process HTTP events, and can extend the functionality of the Web proxy . By using the Internet Server application programming interface (API), ISA Server supports the Web filter extensibility model, which lets third-party developers examine and change the HTTP request and response flow. ISA Server does not support ISAPI extensions.
For more information about ISA Server support of Web filters, see Developing Web (ISAPI) Filters for ISA Server.