Hi.
For example, I have player 1 (who is the server) who instantiate an object with a rigidbody over the network.
The player 1 can push the rigidbody but others players can’t. I would like to know how to implement that over the network.
Hello Honikou, there are many ways you can implement this, but something to try might be to have the server handle all rigidbody motion/collision stuff, and also authoritatively control characters (other network players who join only send input to server which decides how things work out locally based on that input) and all clients do is watch the network position of those objects - without considering rigidbodies, thus allowing the server to logically handle and respond to rigidbodies being pushed around by everyone.
Hope that all makes sense 
and that’s a broad response to your question, but good luck!
Hi MD_Reptile,
I try to add an empty gameobject with a trigger on the player. Then, I OnTriggerEnter with my Ball if this collider collide. The result is not very good because the ball move with lag. ( I use the same script as my player to smooth the movement but that is not enough).
I understand what you say about the server, but I don’t like this kind of gameplay because you have some “roll back” like on guild wars.