Plex and Remote Access

I picked up the Orbi system and configured it with no port forwarding. Today I enabled Plex and remote access is selected. It shows that I have internet connectivity through Orbi to my Plex server and I tested it via my iphone to see that I can access my content (I can). 

So the question is, "HOW?"

There are no ports forwarded (even if plex could auto configure my Orbi I should see the port translation in the advanced settings). 

I can't see any way to view what ports Obri has open and closed but it certainly has the one open which makes me wonder if it really isn't doing any port blocking and I'm hung out on the Internet giving the hacking community a good laugh? 

Questions:

Does Orbi let internal device configure Internet ports? 

Is there a way to see if the Firewall is working?

Is there a way to test ports and view traffic on them? 

I'm real close to pulling the plug on this thing and installing my old firewall. 

Thanks!