How is a machine defined

I am sorry, I am not technical but information risk. I wonder how a machine is connected to the Orchestrator. I see a machine name and a key, but is this a connection through an IP address, a URL or MAc-address or how does these Orchestrator and machine find eachother?
Sorry if it is a stupid question.

Solution to all your queries in the question that you asked.

Hi Caspar,

The connection is always initiated by the Robot, and not by Orchestrator. In Robot Settings you have to provide the Orchestrator URL so the machine can find the Orchestrator. Then, using the robot key and machine name it is authenticated and connected to provisioned robot in Orchestrator.