mx2.nameserver.net.au has no CNAME records.
Question and response
Question
dig mx2.nameserver.net.au. NS
Answer
The response has no answer records.
Authority
nameserver.net.au. 3592 SOA ns1.nameserver.net.au. hostmaster.nameserver.net.au. 2026020104 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0