PUN / .Net server

Hello is there any tutorial for using PUN with a custom server plugin? For example I want to use the photon views on the unity side for simple position sync but want the server to check if the position and velocity are reasonable before relaying it.

I have found tutorials for pun with default cloud and server plugins that uses only send packets.

EDIT:
In particular the .net api seems very bare bones and wonder if there were any add ons for better unity integration.

EDIT2:
I want to have a unity client and a global standalone server without having to use low level pack sends for everything.