The Little Snitch, a well-known tool for macOS that shows which applications are connecting to the internet, is now being developed for Linux. 
The developer said he started the project when he was experimenting with Linux and realized how strange it was not to know what connections the system was making. There are tools like OpenSnitch and various command-line utilities, but none provided the same simple experience of seeing which process was connecting where so that you could block it with a click.
The Linux version uses eBPF for kernel-level traffic monitoring, with the core components written in Rust and a web interface that can even monitor remote Linux servers.
During testing on Ubuntu, the developer noticed that the system was relatively quiet on the network. Over the course of a week, only nine system processes made connections to the internet.
In comparison, macOS showed more than a hundred processes communicating externally.
The applications behave similarly across platforms. Launching Firefox immediately activated connections related to telemetry and advertising, while LibreOffice did not make any network connections during the tests.
The early release is intended primarily as a transparency tool to show what the software is doing on the network and not as an enhanced security firewall.
Although the press releases will range from very select to rare, I said I'd pass...because sometimes the editors hide.
