No, I’m using a STUN server. This issue is unrelated and due to the local IPs being masked by mDNS addresses so that local network topology isn’t leaked to the world at large and my routers handling of mDNS. Which is why everything works over the local network if I disable mDNS use in Chrome. TURN is the ultimate fallback to being unable to NAT punch.

Ironically getting machines connected across the internet with WebRTC has so far been relatively smooth sailing.