If they’re using XMPP like others in the thread mentioned, they’re likely using STUN/TURN for signaling. IIRC according to google, something like 10% of hole pu

If they’re using XMPP like others in the thread mentioned, they’re likely using STUN/TURN for signaling. IIRC according to google, something like 10% of hole punched traffic needs to be routed through the TURN server due to symmetric NAT. For all other types, a nearly persistent connection from server to client is possible with STUN/TURN, since a client can resignal when its connection changes.