What does an IP country of Australia mean?
A database assigned the address to Australia. The retail ASN is the ISP, not NBN. NBN is the access network those ISPs use.
AU
IP addresses in Australia
What a geolocation country of Australia tends to mean, and which networks sit behind it.
Australian addresses are allocated by APNIC. NBN is the access network for a large share of premises, and it does not appear as the ASN on a lookup. The ASN is the retail ISP: Telstra AS1221, Optus AS7474, TPG AS7545, Aussie Broadband AS4764. A Telstra mobile address and a Telstra fixed address are not the same product, and the mobile one is more often shared.
Some Australian ISPs offer CGNAT as the default and a public IPv4 as an option the customer can toggle. That is a plan setting, visible by comparing the router WAN address with the address on this site, not by reading the country code. IPv6 rollout is uneven across those brands. City pins cluster on Sydney and Melbourne for national networks. A right-country, wrong-city result is the usual quality bar, not a sign the database has the premises.
The regional registry is APNIC. What is my IP address · IP location wrong?
Further reading: Cloudflare Radar.
Questions
Which Australian ISPs have their own ASNs?
Telstra AS1221, Optus AS7474, TPG AS7545, and Aussie Broadband AS4764 are the common ones on fixed lines. NBN does not appear as the ASN.