Oh nice! The developers of Little Snitch have made a version for Linux. Like they say at the start of the post, I never found an alternative I was happy with when I switched from macOS to Linux. Although, with vastly more open-source software in my workflow it was also less necessary.

https://obdev.at/blog/little-snitch-for-linux/

#Linux

Little Snitch for Linux — Because Nothing Else Came Close

Recent political events have pushed governments and organizations to seriously question their dependence on foreign-controlled software. The core issue is simple and uncomfortable: through automatic updates, a vendor can run any code, with any…

Objective Development

@wezm

OpenSnitch already exists. I've been using it for a while.

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

GitHub - evilsocket/opensnitch: OpenSnitch is a GNU/Linux interactive application firewall inspired by Little Snitch.

OpenSnitch is a GNU/Linux interactive application firewall inspired by Little Snitch. - evilsocket/opensnitch

GitHub
@jackwilliambell yeah I tried it (the post also mentions it), but it didn't give me an experience equivalent to Little Snitch on macOS. Sorry it was a while ago, and I didn't remember the specific reasons that stopped me sticking with it.
@wezm @jackwilliambell same experience. I should give OpenSnitch another try before trying LittleSnitch.