Skip073: Firewall is off! should it be on maybe?
On Mac, it's off by default. And for this (i.e. installing), you should leave it off. Still, first time you use the program, you'll get the typical splash screen from Mac (it's something like this program is downloaded from the internet; do you want to open).
If you choose to enable it after this, that's something easily done. Still, if you're practicing safe computing practices, you should never have a problem with leaving it off.
I've never used a firewall (even when I had Windows-based computers). And in some form or another, I've been online for over 25 years. Never had an issue.