I have several computers (one OSX wired, several Ubuntu/Mint wifi) behind a NAT, and they never show a local IP address in the web GUI, only the public IP. I have all their firewalls configured to allow TCP 22000 and UDP 21027. They also see each other whenever I add a new device.
Is this normal behavior? Are they direct-connecting over LAN in the background and I just can’t see it?
If the network prevents broadcasts and multicasts then they won’t discover each other over land addresses. Also, your access point mind be in guest mode or partition different devices into different subnets. Best to check subnets on each machine