Question and response
Question
dig 153.124.253.145.in-addr.arpa. NS
Answer
153.124.253.145.in-addr.arpa. 5 CNAME 153.sub128.124.253.145.in-addr.arpa.
Authority
sub128.124.253.145.in-addr.arpa. 108 SOA ns4.sophos.com. hostmaster.sophos.com. 2013012202 7200 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0