One of the new features included with the TMG firewall is the URL filtering feature. URL filtering enables the TMG firewall to block sites, on a per category basis if you like, to block (or allow) sites using the built in database included with the TMG firewall (actually, the URL filtering feature is a licensed feature).
However, one problem with the TMG URL filtering feature is that if the site isn’t categorized, there isn’t an easy way to block the unknown site. At least until now.
Check out the article Configuring Forefront Threat Management Gateway (TMG) URL Filtering to Fail Closed by Richard Hicks over at http://tmgblog.richardhicks.com/2010/05/24/configuring-forefront-threat-management-gateway-tmg-url-filtering-to-fail-closed/ to solve this problem.
DEBRA LITTLEJOHN SHINDER
MVP (Enterprise Security)