LuLu
LuLu is the free macOS firewall:
Documentation:
Full details and usage instructions can be found here.
To Build:
LuLu should build cleanly in Xcode (though you will have to remove code signing constraints, or replace with your own Apple developer/kernel code signing certificate).
To Install:
Simply run the installer application: LuLu Installer.app
brew install --cask lulu
To Support:
Mahalo!
LuLu is supported by the "Friends of Objective-See" such as:
...the standard in Apple enterprise management.
...modern Apple MDM & security for enterprise & education.
...next-generation Apple enterprise management.
...the worldโs most-loved password manager.
...an all-in-one package to awesomize your Mac.