refer url:http://www.isaserver.org/tutorials/Configuring-ISA-Server-2006-HTTP-Filter.html
In this article I will give you a high level overview of the ISA Server 2006 HTTP Filter. I will show how to use this HTTP Filter to protect your internal network from some types of attacks in Webserver Publishing scenarios. We will also see how to prevent users from using the Universal Firewall Bypass protocol