Tested on: Ubuntu 18.04.3 (LTS) x64
This is the first try to make a NAT Proxy, which it's used as apps Anti-DDoS, or games Anti DDoS script, that work on filter all the packets and drop the bad ones then reroute the good ones to the destination server.
This is just test version, not final so please stay tuned for the coming updates.
GRE Tunnel not finished yet, still working on it :)