Secure UCP Phone, NAT and Stun

Real quick FYI - Set up all the ports and firewall rules correctly, but in-the-wild UCP Phone had no audio.

Testing from a connected LAN (different subnet but connected) to the server, even though I was using it’s external address and routing out, worked perfectly, but in the “Wild”, no audio.

Added a STUN server and applied and bingo - perfect audio.

There are lot’s of posts here about UCP and Phone from years ago, but very few of them talk about using HTTPS.

Second post to “Solve” the post.

I don’t know how much needs to be said about using HTTPS. Documentation pretty much makes it clear. First page I found in the wiki for UCP Phone notes that encrypted connection w/ valid certificate is required for the phone:

Days are long gone since any browser would allow an unencrypted webrtc application.

That said… your post seems to be more about STUN than HTTPS. Did the default not work?

Nope - just doing it with SSL and this document:

WebRTC Phone-UCP - PBX GUI - Documentation (

The section about STUN is at the very bottom - so it didn’t jump out to me - maybe everybody else already knows this, but I didn’t for this specific problem - we have NEVER had to use a STUN server for anything before.

If your PBX is on a public IP address (no NAT) you should not require STUN. Otherwise, yes.

The PBX IS on a Public IP AND it needed STUN - That is why I posted.

Interesting, thanks.

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