Which one can use VNC/RDP?

Question

Windows

Given:
1. The user's computer on Windows OS that is logged in under AD
2. The user who is currently working on the computer
Task:
You need to connect to his session, and so that the user from a remote location, if he moves the mouse, then it moves from the user who is in front of the computer. I know one implementation - Teamviewer.
All is well, wonderful. Only this solution must still be bought, because too much time will have to be spent remotely and sooner or later it will give out. In short, we are looking for the Teamviewer type option, only for free

Answer 1

Tight VNC.