https://www.reddit.com/r/privacy/comments/2tws96/websites_can_now_use_webrtc_to_determine_your/
https://www.perfect-privacy.com/check-ip/
https://diafygi.github.io/webrtc-ips/
Workarounds:
For Firefox: Use about:config, search for 'media.peerconnection.enabled' and set it to FALSE
privacy.trackingprotection.enabled;true
or for chrome use this extension: https://chrome.google.com/webstore/detail/webrtc-block/nphkkbaidamjmhfanlpblblcadhfbkdm?hl=en
Workarounds:
For Firefox: Use about:config, search for 'media.peerconnection.enabled' and set it to FALSE
privacy.trackingprotection.enabled;true
or for chrome use this extension: https://chrome.google.com/webstore/detail/webrtc-block/nphkkbaidamjmhfanlpblblcadhfbkdm?hl=en