Buy a domain name, point it at Enterprise Business Inc.'s server, submit a link using your domain to a form the operate which does a if (internalURLs.conta

Buy a domain name, point it at Enterprise Business Inc.'s server, submit a link using your domain to a form the operate which does a if (internalURLs.contains(submittedURL)) { check. Then change your DNS records to point to some other server, once your domain is in their database and they assume it to have already been validated as internal.