"Introducing OpenSnitch, a free and open-source application firewall for GNU/Linux systems. This interactive tool allows users to monitor and control network traffic, ensuring their system's security and privacy. With key features like real-time traffic monitoring and customizable rules, OpenSnitch provides a powerful layer of protection against unwanted connections. Developers and users alike can participate in the project community and contribute to its growth. Learn more about OpenSnitch and how you can get involved at https://github.com/evilsocket/opensnitch."

Source: https://github.com/evilsocket/opensnitch