Developing Web Filters for Forefront TMG

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

In Forefront TMG 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 Forefront TMG. These are described in ISAPI: Comparing IIS and Forefront TMG.

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Build date: 11/30/2009

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