Url Blocker is a simple tool that enables you to block certain Internet sites by making them inaccessible from any browser.To block a site, simply add the domain name(s) to the block list. You can save the list of sites and reload it later or switch between different block lists. You can remove sites from the list at any time.Ulr Blocker uses the Windows HOSTS file to make the specified sites inaccessible. The HOSTS is a Windows feature that provides a local DNS lookup for Internet enabled applications, including web browsers. The program adds entries to the HOSTS that cause your "blocked" sites to be redirected to your local IP address (127.0.0.1) which will cause your browser to produce and error "Unable to connect" or similar.