> For keeping tabs on what your software is up to and blocking legitimate software from phoning home, Little Snitch for Linux works well. For hardening a system

> For keeping tabs on what your software is up to and blocking legitimate software from phoning home, Little Snitch for Linux works well. For hardening a system against a determined adversary, it's not the right tool. What would be the right tool to harden in a similar way to little snitch on mac? Meaning intercepting any connection and whitelisting them reliably.