Protoport Personal Firewall will protect your computer against hacker attacks like denial of service (DoS) or port scan. User can specify what exactly programs may connect to internet, and how (specify local and remote ports, protocols etc, for every program). Also there is an option to limit bandwidth for certain programs and even computers (when running on server). Web Guard feature will block unwanted popups, ads, java script, and some other information like referer and user agent.