Quote: nd send only 'n' frames a checksum from the server to the clients(for correction).
If your physics is on the client, how does it know it needs corrected? How do you know your client isn't sending the other players a fake physics update to avoid a bullet!?
Quote: It would be the wrong way to have _all_ physic entites only on the server side, because the server must send every object's positon every frame to create a very 'smooth' movement/and so on.
Absolutley. Sending a network update EVERY change is not the right way to do it. So why must the server send every object position every frame? This is NOT needed for smooth movement under ANY architecuture. Dead Recknoing is one example of how to deal with this.
Your native approach is DO-ABLE in LAN but will crash spectacularly in WAN or with more than a few players.
