title: maps api v3 behind a proxy
body: <p>i developed an application that is perfectly using maps api.
  Today a customer ask me why his google maps is appear completely white on the website, and therefore I discovered that he uses a proxy on his network.
  This proxy is set as "deny all" and my customer grants access host by host.
  My question is, which host he must enable for allowing that maps api will work correctly?
  My website uses API V3,
  Thanks</p>