A GET request on the /whoami endpoint MUST return http status 200 OK with the body containing the customer’s <device-identifier> that the customer MUST include in their payment event.
http port MUST be the same as HTTP-01
Formatted as [type]=[value]
curl -X GET http://192.168.1.1:2121/whoami # TollGate IP
HTTP/1.1 200 OK
Content-Type: text/plain
Content-Length: 20
mac=00:1A:2B:3C:4D:5E