IPv4 vs IPv6: what your public IP is actually showing
The short number and the long one, why both show up on IP lookup, and how IPv6 leaks a VPN.
Your public IP address is the number the rest of the internet uses to send traffic back to you. IPv4 is the older, shorter form most people still see first. IPv6 is the longer form that the internet is slowly moving toward. Knowing which one a site recorded, and checking both on a what is my IP tool, is part of basic IP lookup and privacy hygiene.
What IPv4 actually is
IPv4 looks like four groups of numbers, for example 203.0.113.10. There are about 4.3 billion of those addresses. The world ran out of spare ones years ago, which is why carriers share them and why your phone and home router often do not have a unique public IPv4.
When you search “what is my IP address,” most pages show IPv4 first because websites, firewalls, and IP geolocation databases still index it heavily. An IP tracker, ISP lookup, and many VPN servers are still built around IPv4.
IPv4 can be dynamic (the ISP rotates it) or static (it stays put). Neither version is a street address. It is a network label.
What IPv6 looks like and why it exists
IPv6 is a long hexadecimal string with colons. It was designed so every device can have a unique public IP without NAT. Your laptop may have both: IPv4 through the router’s shared address, and IPv6 straight from the ISP.
If a VPN only wraps IPv4, IPv6 can leak. That means a site can still see your real ISP path while you think you hid your IP. After you connect a VPN, check IPv4 and IPv6 on this site. If IPv6 still shows your carrier, you have an IP leak.
Which one sites log
A modern browser will try IPv6 when the destination has an AAAA record. Mail apps, games, and IP lookup APIs may log one or both. If you are debugging a ban, a geo block, or a failed login, copy both numbers.
CGNAT (carrier grade NAT) makes many mobile users share one public IPv4. IPv6 is often the identifier that actually distinguishes you on that network.
Practical checks
- Look up your public IPv4 and IPv6 before and after a VPN.
- If only IPv4 changes, turn on the provider’s IPv6 leak protection or disable IPv6 on that adapter.
- For IP geolocation, IPv4 databases are usually denser than IPv6.
- Do not paste either address into a chat you do not trust.
IPv4 vs IPv6 is not a trivia question. It is how you confirm a hide my IP setup, an IP location guess, and whether your ISP still sees the real path.