Question and response
Question
dig mx1.mailbox.org. PTR
Answer
The response has no answer records.
Authority
mailbox.org. 900 SOA ns.jpberlin.de. root.jpberlin.de. 2014137782 40000 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0