A new proxy server is in place.
The "old" one was proxying UDP packet.
The new one is encapsulating locally the UDP packets from FA to a TCP stream to the proxy server.
The proxy server sends that stream back to the other player lobby, and the lobby convert back the UDP packet to send it to FA.
The server will first try to resolve NAT between players, if it fails, it will send the connect method and check if the player manage to connect (can happen). If after 5 seconds, FA is not reporting a connection from that player, the server will fall back to the proxy proxy.
By doing that, we are going around all kind of problem with NAT, firewall, and all other crappy routers problems.
You can think TCP will be slower, and it's true.
But not that much, because we have disabled the Nagle's algorithm (http://en.wikipedia.org/wiki/Nagle's_algorithm) making the stream suitable for low delay protocols like FA.
If you want connect to the FAF lobby, you will connect to the proxy server, meaning that NIL should never happen again.
If you still have some, please, please, report it !
But remember : you have to wait A LEAST 10 seconds to be sure the proxy is kicking in !
It's also works for 1v1 obviously.