[44net] Gateway : How create one ??

Hello, i am coord offrench network 44.151. I want to make gateways : For example, i want ping 44.151.29.1 and i would like to have an answer from my localIP 78.241.81.29. What is the command to the server. I knows these command f5pbg add a 78.241.xxx.xxx etc... but i don't know the command to make gateways... Thank's a lot for the answer. All the best Ludovic - F5PBG.