@Goffi @larma libwebrtc has a config flag for that called iceTransportsType which can be set to 'RELAY'.I believe this is also exposed to browsers. https://codeberg.org/iNPUTmice/Conversations/src/commit/91ccbfe3d51b5f1c69edfb8497563a7014e36437/src/main/java/eu/siacs/conversations/xmpp/jingle/WebRTCWrapper.java#L397-L400