Of course not. If there was a domain reserved for internal use and everyone could get a cert for it, everyone would be able to impersonate your internal hosts.

Of course not. If there was a domain reserved for internal use and everyone could get a cert for it, everyone would be able to impersonate your internal hosts. I don't think there's a way around coming up with a reliable process for renewing your domain. You somehow manage to do it for lots of other things already.