Also, there's a wonderful open standard called ICE - http://en.wikipedia.org/wiki/Interactive_Connectivity_Establishment http://en.wikipedia.org/wiki/Interactiv

Also, there's a wonderful open standard called ICE - http://en.wikipedia.org/wiki/Interactive_Connectivity_Establishment http://en.wikipedia.org/wiki/Interactive_Connectivity_Establ... - that 'properly' encapsulates STUN and TURN into a very effective NAT traversal mechanism. IIRC, Google's Jabber/XMPP library - https://developers.google.com/talk/libjingle/- https://developers.google.com/talk/libjingle/- that was once actively maintained had an ICE implementation that also included access to Google's STUN/TURN relays but sadly this has gone unmaintained.