What your IP address actually is
An IP address is the return address on every packet you receive. A web page, a video frame, a message — each one is routed back to you by that number, and no server can answer you without it. So the address at the top of this page is not something we discovered about you. It is what every site you have ever opened already saw.
That address is the public one, and it usually belongs to your provider
rather than to your device. Inside your home or office your machine holds a second,
private address — 192.168.1.14, 10.0.0.5 or
similar — which exists only on your side of the router. The router rewrites one into the
other on the way out. That translation is NAT, and it is the reason your laptop, your phone
and your TV all appear to the internet as a single address.
Why you may have more than one public address
Almost everyone assumes they have exactly one. Ask twice and the answer sometimes changes, which is why this page does not ask once — it opens connections to several separate hostnames and compares what comes back.
The mechanism is simple. A hostname your browser has not talked to yet requires a new TCP connection, and a new connection is a new decision for your provider's routing equipment. (The DNS answer itself may well come from a cache — browsers, the operating system and your resolver all keep one — but the connection is genuinely new.) Where an operator balances traffic across several uplinks, two connections opened a second apart can leave the network through two different addresses.
If you see more than one address above, it is almost always one of these:
- Several uplinks or load balancing. Your provider has more than one path to the rest of the internet and uses whichever is free.
- Carrier-grade NAT. Your operator maps many subscribers onto a shared pool of public addresses, and your flows do not all land on the same one.
- A leaking VPN or proxy. Part of your traffic goes through the tunnel and part goes around it — the single most common way people are surprised by this page.
Carrier-grade NAT, and why port forwarding stopped working
IPv4 has about 4.3 billion addresses, and the regional registries handed out the last
free blocks years ago — ARIN, which serves North America, exhausted its pool in September
2015. Providers responded by sharing what they had. In a CGNAT deployment your router does
not receive a public address at all; it receives one from the range reserved for exactly
this purpose by RFC 6598, 100.64.0.0/10, and the operator translates it again
on the way out.
Two consequences follow, and both are the reason people end up on a page like this one:
- Nothing can connect to you. Inbound traffic has no unique address to be sent to, so port forwarding, self-hosting, some games and inbound VPN simply do not work — see our subnet calculator if you are trying to work out which of your addresses is which.
- You inherit your neighbours' reputation. Because a single public address can front a large number of subscribers, a block aimed at one of them lands on all of them. That is why a site you have never abused sometimes greets you with a captcha.
The quick test: compare the WAN address shown in your router's admin page with the address at the top of this page. If they differ, there is at least one more layer of NAT between you and the internet.
How to read the details next to your address
- Country
- Where the network is registered — not a location fix on a person. Country-level data is the one part of geolocation that is genuinely reliable; commercial providers put it near 99 %.
- ASN and operator
- The autonomous system: one operator's slice of the global routing table. This is the most dependable answer to "who runs this network", because it comes from routing itself rather than from a marketing database. Look up any address on our IP lookup page.
- Reverse DNS (PTR)
- The name the network owner attached to the address. Provider PTRs often leak the city, the access technology or the equipment model. Many addresses have no PTR at all, which means nothing in itself.
- Network type
- Whether the range looks like a consumer provider or a data centre. Data-centre ranges are what a VPN, a proxy or a rented server looks like from the outside. We say "not classified" whenever we are unsure, rather than guessing.
How precisely can anyone locate you?
Not to your street, and not to your building. Vendor marketing and independent measurement disagree sharply here, and the disagreement is the most useful thing to know: country accuracy is around 99 %, but studies comparing commercial databases against consented GPS ground truth find that only a minority of addresses resolve to within ten kilometres of the actual user, with typical errors running into hundreds of kilometres for mobile and satellite ranges.
There is also a well-documented failure mode: when a database cannot place an address more precisely, it returns the centre of the city, the region or the country. Whole neighbourhoods — in one famous case a single farm in Kansas — have spent years being the apparent home of millions of addresses because a default coordinate pointed there. This is why we show you a country and an operator and stop, instead of drawing a confident pin on a map.
IPv4, IPv6 and what your browser prefers
IPv6 addresses (2001:db8::1) exist in quantities that will not run out, and
when a site is reachable over both protocols, a modern browser normally tries IPv6 first,
falling back to IPv4 within milliseconds if it fails. If the IPv6 line above shows nothing,
your connection is IPv4-only — still perfectly usable today, and still the reason inbound
connections are awkward for you. Our IPv6 test checks it directly
from your browser, and what your browser reveals
shows the rest of what a site reads about you without asking.