Could it be a possibility to generate a keypair on the machine and then attempt to register itself to your webserver supplying client-name, IP and public-key. T

Could it be a possibility to generate a keypair on the machine and then attempt to register itself to your webserver supplying client-name, IP and public-key. Then you would be able to see and OK any attempts to connect. Once you've OK'ed it, it would be able to authenticate and communicate normally as an authenticated device.