Apex domains cannot have CNAME records.
Question and response
Question
dig dnstest.iprimus.net.au. NS
Answer
dnstest.iprimus.net.au. 5 NS ns1.dnstest.iprimus.net.au.
Authority
The response has no authority records.
Additional
ns1.dnstest.iprimus.net.au. 5 A 210.50.30.77
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0