State Sincronization

It's me again... with another question regarding networking. (I am porting a game mockup from single player to multy-player...)

If I assign to a Network View component the Transform of an object.... this object's transform (position mainly, i don't care about rotation in this case, and will optimize this later) will get sincronized other the network on every network update cycle.

BUT: since this object has also a sphere collider, a configurable joint locking it's Z axis movements and a rigidbidy, WHO will make the calculations for the collider? the server? a random client?

Thanks for your help, more questions on their way,
philip