> Although I don't know what to do with that information...
Block him with firewall rules, would be my guess, or build it into the DNS server to deny
them. Similar to setting up rules to block people that attempt to brute force a ssh password
Of course that would lead to interested DOS possiblities. Like having some goofy webpage or
emailing somebody with a html email that have images that link to thousands of non-existent
servers with fake dns names.