How your IP address actually works
An IP address is the return address of your internet connection. Every request your device sends is cut into packets, and each packet carries the address the answer must be delivered to. That is the whole reason this page can greet you with a number the moment it loads: you handed it over by connecting, the same way a postal envelope carries a sender address.
Why every website can see your address
There is no clever detection script behind this page. When your browser opens a connection, the network stack puts your public address in the source field of the packet, and the server reads it straight from the socket. Sites behind a CDN read it from a forwarded header that the edge network adds. You cannot switch this off, because a connection with no return address would simply never receive a reply.
What a site gets is only the address of the last hop between you and the internet — usually your router or your provider's gateway. Everything inside your home keeps a private address such as 192.168.1.12, which never leaves your network. This is why your phone, your laptop and your console all appear online under the same public address.
IPv4 and IPv6: why you may have one or both
IPv4 addresses look like 203.0.113.45 and come from a pool of roughly 4.3 billion combinations. That pool ran out years ago, so providers now share a single public address between many customers using carrier-grade translation. IPv6 solves the shortage with a far larger space and addresses written in hexadecimal, such as 2001:0db8:85a3::8a2e:0370:7334.
To test both independently, this page opens two separate connections: one to a host that only publishes an IPv4 record, and one to a host that only publishes an IPv6 record. If the second connection succeeds, your network really has a working IPv6 path. If it fails, there is nothing wrong with your device — your provider or your router simply does not offer IPv6 yet, which is still true for a large share of connections worldwide.
Because the two connections travel over different protocols, they can even end up on different networks. A laptop on a dual-stack fibre line often shows a stable IPv6 prefix next to a shared IPv4 address, and a phone on mobile data may show an IPv6 address while its IPv4 traffic is translated somewhere inside the carrier network.
Why the location on the map is often wrong
IP geolocation is a database lookup, not GPS. Providers register blocks of addresses with a regional registry, and geolocation vendors combine that registration data with routing information, latency measurements and customer submissions to guess where a block is used. Nothing in that chain measures where your device physically is.
When a vendor is unsure, it falls back to the centre of the area it believes the block serves — a city centre, a regional midpoint, or in the worst case the geographic centre of a whole country. That is why two lookup services can disagree about your city, why the marker can sit in a town you have never visited, and why coordinates should be read as "somewhere in this region" rather than an address.
Mobile networks, satellite links, corporate VPNs and business lines are the least accurate of all, because a single gateway can serve traffic from an entire province or country. If the map is wrong for you, the fix is with the geolocation database, not with this page: most vendors publish a correction form where the address holder can submit the right location.
How to change or hide your address
Most home connections receive a dynamic address, so rebooting the router or leaving it off long enough for the lease to expire can hand you a new one. A VPN or proxy goes further: your traffic is encrypted to a server, and every site then sees that server's address instead of yours. Tor chains several relays for stronger separation at the cost of speed.
None of this is perfect. A browser can still leak your real address through WebRTC even while a VPN is active, DNS queries can escape the tunnel, and the address a VPN gives you is frequently flagged as a datacentre range by streaming and banking services. It is worth verifying the result rather than trusting that a VPN is switched on: run the WebRTC leak test and the proxy check on this site right after connecting.
Finally, keep the risk in perspective. Your address is visible to every server you contact, and on its own it identifies a network rather than a person. Only your provider can map it to a subscriber, and normally only does so on a legal request. Sensible hygiene — updated router firmware, no unnecessary port forwarding, a VPN on public Wi-Fi — covers almost everything that matters.