OpenTok now supports TURN over TCP

Connectivity, we at TokBox believe, is one of the cornerstones of real-time communication applications. So we are happy to announce that we now support TURN over TCP.

There are several technologies which are used to help establish connectivity in WebRTC. The first mechanism is using a protocol called STUN. STUN uses a ping-pong mechanism to find the public IP of a client end-point so that a peer-to-peer session can be established and one can traverse a firewall. While this is useful in a number of scenarios, there are cases where one could be behind symmetric NATs, where STUN does not suffice. TURN helps in these cases. TURN is a mechanism by which real-time media can be relayed through a TURN server to punch through firewalls. OpenTok seamlessly supports STUN and TURN so a developer doesn’t have to worry about how to setup up these servers, scale them, establish connectivity etc.

But we work with several partners who work within enterprises or in highly “managed” network environments. Sometimes both STUN and TURN as they exist are just not enough. This is because TURN for the most part was only supported over UDP by browsers. We are now happy to announce for TURN support over TCP (in addition to UDP) in the OpenTok Cloud (supported in Chrome 29 browsers and coming to FireFox shortly). We require only that port 443 to be available to make this work. Application developers using OpenTok will now benefit from improved connectivity without having to do anything specific in their application code. This in turn (pun intended!) delivers a better user experience.

Give it a spin and let us know if you have any questions.If you have any feedback/question, feel free to reach out to TokBox at

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