Koffix Blocker is a desktop application that helps you to block or restrict sites that are involved in questionable practices. When you surf the web you may sometimes accidentally visit sites that, for example, try to install some sort of spyware on your computer. If you had known that beforehand you probably wouldn`t have visited these sites at all. Koffix Blocker can help you block these sites. To block a site, Koffix can simply add it to the HOSTS file.