LuLu by Objective-See is described as 'LuLu is the free, shared-source macOS firewall that aims to block unknown outgoing connections unless explicitly approved by the user' and is a popular Firewall in the network & admin category. There are more than 10 alternatives to LuLu by Objective-See for a variety of platforms, including Mac, Android, Linux, Windows and iPhone apps. The best LuLu by Objective-See alternative is Portmaster, which is both free and Open Source. Other great apps like LuLu by Objective-See are GlassWire, Little Snitch, NetGuard and OpenSnitch.