Extending ISA Server with XML Web Filters

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Published: October 19, 2001

Summary

In a business-to-business environment, application-level filtering is crucial to protect the private processes of your servers. Microsoft Internet Security and Acceleration Server 2000 enables developers to design custom filters to satisfy specific security needs. Using the ISA Server Software Development Kit (SDK), developers can build custom extensions in C++ to filter the traffic that passes through the system. This document describes a custom Extensible Markup Language (XML) Web filter built for ISA Server. The filter examines XML documents and verifies the XML before routing the documents to the backend systems, providing an additional layer of protection for your computers running Microsoft BizTalk Server.

Included in this document:

  • Meeting the Security Needs of a Business-to-Business Environment

  • The XML Filter Sample Code

  • Internet Information Services (IIS) File Drop Version

  • Performance Impact of the IIS Web Filter

  • Extending the XML Filter to Other Purposes

  • BizTalk Server and ISA Server

Note: The sample code contained within this paper is intended as a proof of concept of XML filtering and it is not supported by Microsoft.

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