5.161.196.64.in-addr.arpa.
Question and response
Question
dig maile.osgbilling.com. PTR
Answer
maile.osgbilling.com. 1800 PTR 5.161.196.64.in-addr.arpa.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0