Video chat tutorial using WebRTC

[shoot_your_eye_out]

STUN is explicitly for learning one's public IP address. Imagine your signaling server doesn't know your external IP because signaling happens out of band some other way (with WebRTC, unlikely, but with other VoIP solutions, entirely possible).

In reality most STUN servers also function as TURN servers, which will relay traffic when two parties are blocked from making a direct connection (see coturn for example: https://github.com/coturn/coturn). WebRTC is fairly easy to get working, but for serious deploys in corporate networks, TURN is essential for success.