Developing Web Filters for ISA Server

Internet Security and Acceleration Server 2004/2006 SDK

Web filters detect and process HTTP request notifications. ISA Server 2004 supports ISAPI filter development, with additional functionality to that provided with Internet Information Services (IIS) and ISA Server 2000. ISA Server 2004 operates independently of IIS, while using the definition of ISAPI functions and structures provided in the Microsoft Windows Server™ 2003 Software Development Kit (Platform SDK). This section provides information about ISAPI filters, as implemented in ISA Server 2004.

In ISA Server Management and in the product documentation, ISAPI filters are referred to as Web filters.

For general information about ISAPI filter development, see ISAPI Filters on the MSDN Web site.

Note to Developers of Web Filters for Internet Information Services

There are several differences between implementation of ISAPI in IIS and in ISA Server. These are described in ISAPI: Comparing IIS and ISA Server.

This section contains the following topics: