# The following from ipleak.net:

WebRTC implement STUN (Session Traversal Utilities for Nat),
a protocol that allows to discover the public IP address.
To disable it:
    Mozilla Firefox: Type "about:config” in the address bar.
        Scroll down to “media.peerconnection.enabled”,
        double click to set it to false.
    Google Chrome: Install Google official extension
        WebRTC Network Limiter.
    Opera: Type "about:config" in the address bar or go to
        "Settings". Select "Show advanced settings" and
        click on "Privacy & security". At "WebRTC" mark
        select "Disable non-proxied UDP".

# Test for leak:
http://ipleak.net

# WebRTC provides peer-to-peer call capability
# e.g. video calls, but is a security hazard

# Firefox:
about:config
# search for:
peerconnection.enabled (or media.peerconnection.enabled)
# in the found record, double-click on "true"
# - this will change it to "false"