Then your app can run a web service to provide that localized information.
As it is the only one that knows the required information, it should be the one to serve it.
http://127.0.0.1:9999/
returns only:
"gbd73gb8eb34"
^ the unique "identification string"
Or the FQDN:
"gbd73gb8eb34.your.domain"
OR a redirection to the resource being requested:
return 301 https://gbd73gb8eb34.your.domain:5001/