The reverse DNS of your instance is actually the name of your OpenStack instance. Before using, we validate the name of your OpenStack instance with the following checks
Is the name that you’ve given the OpenStack instance actually a domain name?
If we lookup the (forward) DNS, do we get a IP address back that is connected to the instance?
If you run a mail server on port 25, does this return the same hostname when we send a HELO / EHLO request?
If all of those checks match, the reverse DNS address will be set to the name of your instance.
If you already have an existing instance in OpenStack, but the name does not yet match those requirements, you can easily change it via the OpenStack API or by using our Skyline interface. We will check once a day if the requirements are met.
If the checks fail, a reverse DNS will be generated. For example vm-<uuid>.public.cloudvps.com