That works with UDP hole punching (https://en.wikipedia.org/wiki/UDP_hole_punching https://en.wikipedia.org/wiki/UDP_hole_punching), and there is a branch with

That works with UDP hole punching (https://en.wikipedia.org/wiki/UDP_hole_punching https://en.wikipedia.org/wiki/UDP_hole_punching), and there is a branch with uPNP (https://en.wikipedia.org/wiki/Universal_Plug_and_Play https://en.wikipedia.org/wiki/Universal_Plug_and_Play) support. We still need to review that code carefully before accepting it into master.