Introduction to managing URL filtering
Updated: February 1, 2011
Applies To: Forefront Threat Management Gateway (TMG)
URL filtering allows you to create access rules that allow or block access to Web sites based on their categorization in the URL filtering database. When a request to access a Web site is received, Forefront TMG queries the remotely hosted Microsoft Reputation Service to determine the categorization of the Web site. If the Web site has been categorized as a blocked URL category or category set, Forefront TMG blocks the request.
If a user requests access to a Web site and discovers that access to the Web site is blocked, he receives a denial notification that includes the denied request category. In some cases, the user may contact the administrator to dispute the categorization of the Web site. In such a case, you must check that the URL was categorized properly (see Looking up a URL category). If the Web site was not categorized correctly, then you must create a custom setting for this URL (see Overriding URL categorization).