Comment 34 for bug 1689087

Having a broker sounds like an alternative, but I have no idea whether this is possible with Go. But it might be worth a try.
What is the problem with permanently open ports in the firewall? If no process is listening on them, it should not matter. And if someone manages to start an arbitrary process on the metaserver, we have pretty much lost anyway. Am I missing something?

Looking at other games is a good idea. You already mentioned 0AD some time ago in #6 and we (as in: I) decided against their approach (hole punching) since it is not reliable. Megaglest and OpenTTD require manual port forwardings.
Battle for Wesnoth seems to be using a relay server similar to our plans, according to this article:
http://www.aosabook.org/en/wesnoth.html
I haven't looked at the sources yet, might be interesting.