Lulu is a software protection tool equipped with several functions that help users monitor and control unauthorized connections from the Internet. It can be considered a backup for the pre-installed macOS firewall.
The GUI is decent, the background is a mixture of black and green colors, and the main window is user-friendly, having a main menu tab and an info display area. Yet, the design of the buttons looks outdated and the text style seems like a bad choice.
Lulu provides individuals a few nice features, such as continuous protection against unauthorized connection attempts. With this feature, malware that blocks the application's data route to the server is immediately detected.
Furthermore, it works great in conjunction to Apple's built-in firewall. One monitors the outgoing network connections and the other one blocks unauthorized incoming connections.
Last but not least, Lulu has no ads, time trials, or missing features. Yet, at this moment, it only supports installation for one single user, but future versions will include a multiple users option.
To summarize, Lulu is a smart utility, complementary to Apple's firewall, it uses a low amount of system resources and has no major bugs. Give it a try.