Essayez le code :-)

Son texte d'accompagnement sur GitHub est clair "Firefox and Chrome have implemented WebRTC that allow requests to STUN servers be made that will return the local and public IP addresses for the user. These request results are available to javascript, so you can now obtain a users local and public IP addresses in javascript. This demo is an example implementation of that."

Alors comment ? Je n'ai pas approdonfi, mais à priori l'implémtantion WebRTC fourni l'adresse IP locale au serveur STUN en fonctionnement normal.