I don't use VPNs. For me, the more alarming information here is that SOCKS and Tor proxies are also leaking IP addresses. If a SOCKS proxy is configured in browser, isn't it the browser's responsibility to ensure all outgoing traffic - including WebRTC - goes via the proxy? Are these browser bugs? Update: Can confirm Firefox Quantum with SOCKS proxy leaks the address. Oh dear! Update 2: I didn't realize this is how W…
But no, WebRTC added data-channels. They have no good use to be silent and especially not to override SOCKS proxy. In fact, some key people on the WebRTC group, when I pressed them, could not provide a single real use-case for silent data channels.
Firefox is absolutely in the wrong to ignore your proxy settings, especially without getting consent first to start a call. It's a complete mess. Regardless of what the "spec" says, Firefox is responsible for implementing broken software that harms users.
Then again, so is STUN/ICE and basically every single thing that has to do with SIP/VoIP. It's like they go out of their way to be obtuse and come up with shitty standards then take glee in how bad it gets. As an example, look up SIP Torture Tests. There's an RFC just to illustrate the moronic edge-cases in SIP parsing that at one point implies your software needs to be conscious to infer the intention of malformed messages.
t. been working in telecom for far too long