[abvdasker]

Though I agree with you that IPv6 will be a boon to P2P networking, your statement is mostly incorrect. STUN can penetrate the most common types of NAT including full-cone, restricted-cone and port-restricted-cone[1]. As the other comments note, TURN can almost always get the job done with other NAT configurations.

The WebRTC API is actually surprisingly robust. It was built with these limitations in mind, so client code can supply a list of STUN and TURN servers, which the ICE framework underpinning WebRTC uses in the order they were supplied. So if setup correctly, WebRTC clients can use TURN as a backup when STUN isn't enough.

[1] https://en.wikipedia.org/wiki/STUN#Limitations

[oandrei]

Here in Brazil, all NATs are either defective or ``symmetric'' whatever this means I am not an expert sorry. I do not expect STUN to work. As for TURN, this means traffic will go through the server. Then how is it better than Skype? Microsoft can afford, if I understand it correctly, a huge network of TURN servers, essentially. Is this how Skype works?