Client & Server speedtest over UDP with reverse port opening

I need a version of iperf [login to view URL] created to support the ability to do a speed test over UDP while being behind the NAT. I have a client that is sitting behind a home router and I need to test the full speed of his internet connection. I don't like TCP based speed tests because as latency increases from the client to the server, in the TCP test is not a true test of the connection speed of the client at the client ISP. The basic logic of what is needed is the following: - server is running on a host machine on my network, which is in front of NAT i.e, has a public ip address - client initiates a UDP or TCP session to the server, and exchanges details with the server i.e. the public IP of the client network - after the client initiated this session then the server can push UDP or TCP bandwidth test to the client - in short we are doing a reverse port opening so that we can do a UDP test from the client to the server, both directions one at a time, in UDP. The main goal of this project is to be able to have a full bidirectional speed test without needing to manually open ports on the client side because it is sitting behind the NAT.