opensnitch

Interactive application firewall

OpenSnitch is a GNU/Linux interactive application firewall. 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.