User Agent: Mozilla/5.0 (X11; FreeBSD amd64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.153 Safari/537.36 Steps to reproduce: Go to http://www.whatismybrowser.com/ Actual results: Section "Your local IP addresses" shows my local computer's LAN addresses. Expected results: This information is not relevant to the web browsing. The only IP address they should know is the public address on the internet from which the browser connects.
http://net.ipcalf.com/ Can set media.peerconnection.enabled to false as workaround.
Note also that it's possible to scan LANs to determine active IPs without WebRTC (<img>-loading failure timing, etc), and likely to infer own-IP.