mail-crm-rr04.avature.net.
Question and response
Question
dig 158.128-255.158.137.209.in-addr.arpa. PTR
Answer
158.128-255.158.137.209.in-addr.arpa. 360 PTR mail-crm-rr04.avature.net.
Authority
128-255.158.137.209.in-addr.arpa. 172800 NS ns-1216.awsdns-24.org.
128-255.158.137.209.in-addr.arpa. 172800 NS ns-1726.awsdns-23.co.uk.
128-255.158.137.209.in-addr.arpa. 172800 NS ns-508.awsdns-63.com.
128-255.158.137.209.in-addr.arpa. 172800 NS ns-557.awsdns-05.net.
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0