opensnitch

GNU/Linux interactive application firewall

OpenSnitch is a GNU/Linux firewall application. Whenever a program makes a connection, it'll prompt the user to allow or deny it. The user can decide if block the outgoing connection based on properties of the connection: by port, by uid, by dst ip, by program or a combination of them. These rules can last forever, until the app restart or just one time. The GUI allows the user to view live outgoing connections, as well as search by process, user, host or port. OpenSnitch can also work as a system-wide domains blocker, by using lists of domains, list of IPs or list of regular expressions.