ns1.optusnet.com.au has no MX records.
Question and response
Question
dig ns1.optusnet.com.au. MX
Answer
The response has no answer records.
Authority
optusnet.com.au. 3600 SOA ns1.optusnet.com.au. hostmaster.optusnet.com.au. 2026012800 3600 1800 3600000 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0