!til &junkworks Clients behind NAT that want to receive data via UDP from a server outside of the NAT must first send a dummy packet to the server they want to hear back from. Also the server has to send its response to the same port as the client's dummy packet port. And the client still might not even receive the server's packet because NAT can choose to send the client's packet out on a different port that the port that was specified by the client. 😩 #necessarybutnotsufficient