esa2.spamcop.iphmx.com.
Question and response
Question
dig 151.143.232.68.in-addr.arpa.iphmx.com. PTR
Answer
151.143.232.68.in-addr.arpa.iphmx.com. 3600 PTR esa2.spamcop.iphmx.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0