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Check Your Public IP and Reverse DNS

A public IP lookup shows the internet-facing address your connection uses to reach websites and online services. It may reveal an IPv4 address, an IPv6 address, or both, depending on the network and lookup tool. Free browser-based utilities on CoderVortex provide a quick result without installing software or learning command-line syntax.

Reverse DNS works in the other direction: it looks for the hostname linked to an IP address through a PTR record. That can identify a mail or hosting network, but it does not identify the individual using the connection. Plenty of valid addresses have no reverse hostname at all.

Australian networks add some useful context. NBN Co supplies wholesale broadband, while retailers including Telstra, Optus, and Aussie Broadband determine the package you buy. Fixed-line IPv4 and mobile connections can use carrier-grade NAT, meaning a lookup may show a shared public address rather than one reserved for your router.

What your public address reveals

Start by separating the local address from the public one. A device normally receives a private address such as 192.168.1.20 for traffic inside the home, while the router sends traffic onward using a public-facing address. With CGNAT, the router may receive a shared address in the 100.64.0.0/10 range instead of a dedicated public IPv4 address.

Check Main result Best use Important limit
Public IP IPv4 or IPv6 seen by remote servers Confirm your current egress address It may belong to a proxy, VPN, NAT, or mobile network
Reverse DNS PTR hostname, if configured Recognise mail or hosting infrastructure Missing or generic records are common
Forward DNS A or AAAA records for a hostname Verify that a hostname resolves to an address DNS can be stale or intentionally arranged
Geolocation Approximate city, state, country, and network owner Check broad routing and network context It does not reveal a precise street or user

The comparison above is the quickest way to see which result answers your question. A browser lookup reports what remote servers currently see, which can differ from the router's WAN address when a VPN, proxy, or corporate gateway is active. IPv6 may also use temporary privacy addresses, so the exact value can change while the underlying connection remains the same.

How reverse DNS checks work

Reverse DNS starts at the address's PTR entry in the DNS hierarchy. For IPv4, the lookup uses a reversed form of the address under in-addr.arpa; IPv6 uses a similar nibble-reversed structure. A school, cloud platform, or ISP may publish a descriptive name such as a mail gateway or edge-node label, while a residential connection may return nothing.

To test an address, paste it into a free reverse-DNS field, then run any returned hostname through a forward DNS check. Matching A or AAAA records strengthen the result, but they still do not prove ownership: hosted domains can point to shared infrastructure, and stale DNS records are common. If you are moving a hostname or configuration record between systems, an online CRC32 checksum can verify that the copied data matches its source, although it cannot validate DNS ownership.

Interpreting Australian lookup results

Australian results often mention an Australian network or a .au domain. That is more informative than a generic cloud name, but it can still conceal the connection method. The NBN Co network operates through many retail providers, so a hostname tied to one carrier may sit behind equipment operated by another; reverse records also tend to change when equipment is renewed or IP space is reallocated.

Geolocation should be treated as a network clue, not a precise location. An address registered to an Australian organisation can be routed through a connection point in Sydney, Melbourne, Brisbane, Perth, or Adelaide, while the database owner may still appear as the organisation itself. Expect city-level differences between services and expect the AU country code to be reliable when the address is genuinely Australian.

For a fair dinkum sanity check, compare the public address with the WAN or internet status page supplied by your router, then repeat the lookup after a brief reconnection. In Australian home and small-business support forums, the usual question is simply whether the address is actually theirs. A changed address after reconnecting often means dynamic assignment; an unchanged one may reflect a static lease or CGNAT.

Privacy, proxies and security checks

Before publishing a result, consider who will see it. An IP address can become personal information under the Australian Privacy Act when it is linked to an identified person, and broad location data adds little practical value. Sharing only a coarse network location, redacting the last octets, or withholding the address is safer than posting a live lookup unnecessarily.

Also switch off any VPN or proxy and compare direct and proxied results, since both can legitimately show different addresses. A mismatch does not automatically mean an error. If the purpose is to check exposed services, remember that an online port scanner tests selected network ports and should only be used on devices you own or have permission to assess.

A reliable lookup routine

Use the same sequence each time so results remain comparable. Begin with the public-address lookup, record whether it returns IPv4 or IPv6, and test each family separately. A reverse-DNS result is useful only alongside the address, network owner, and a forward-DNS confirmation.

Keep a small history rather than relying on memory. Dynamic addresses, roaming mobile sessions, and CGNAT pools can all change the route or egress point, so timestamps help distinguish a genuine configuration change from normal network behaviour.