mx05.earthlink-vadesecure.net.
Question and response
Question
dig 107.96-27.240.172.163.in-addr.arpa. PTR
Answer
107.96-27.240.172.163.in-addr.arpa. 300 PTR mx05.earthlink-vadesecure.net.
Authority
96-27.240.172.163.in-addr.arpa. 172800 NS ns-1292.awsdns-33.org.
96-27.240.172.163.in-addr.arpa. 172800 NS ns-1573.awsdns-04.co.uk.
96-27.240.172.163.in-addr.arpa. 172800 NS ns-7.awsdns-00.com.
96-27.240.172.163.in-addr.arpa. 172800 NS ns-829.awsdns-39.net.
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0