Murus — a front end for Mac OS PF Firewall.
I just wanted to let folks know about Murus, a front end for Mac OS's built in PF (Packet Filter firewall). So Murus does not modify OS X PF default configuration and does not install any kernel extensions. It makes only use of tools and functions already built into OS X, using its own configuration files.
I came across this as I am putting together my CrushFTP FTP server which is already up and running but not yet announced. The question I am still trying to understand is if the passive ports (2000-2100) which I have forwarded along with port 21 do in fact open when ftp is accessed. It's not clear to me as I have MacOS Firewall setup to stealth every port. Port 21 is closed so it will work and already does. I guess I could quickly figure this out be making a connection from an external source such as my iPhone's LTE modem but I haven't yet. Oh yeah, CrushFTP is not an app but a JAVA service so Apple's firewall can't detect it as it is not an app.
In the meantime, I am posting this for no reason other than just letting folks know about Murus which looks like really sweet front end for Mac OS's built-in PF firewall.