From http://www.chriskranky.com/webrtc-turn-restricted-network/ - Chris tests WebRTC in a locked-down network environment, but WebRTC still connects just fine.

Many large companies (particularly those with over zealous IT depts) often have port restricted networks. This is almost guaranteed to happen at financial institutes and believe it or not at telecom service providers (who are scared of nearly everything). These networks typically do not support incoming connections and support outgoing connections on TCP Ports 80/443 and maybe (if they’re in a good mood) UDP Port 53 (for DNS). This is not an atypical situation.

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A large financial institute posed the question whether WebRTC using a TURN service can work in this network condition. The answers were far from clear. A definite maybe didn’t satisfy me.

I turned to Lee Sylvester, Senior Engineer at Xirsys, who said YES, that their TURN service would work in this situation. Yeah right, I don’t believe you. He offered to show me. I port restricted my home network (which shut down virtually everything) and went to XirSys’s demo page on Herokuapp and damn if a hobbit didn’t appear in my browser window (Lee is from New Zealand land of mystery and TURN services). It worked.
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