# IP geolocation and IPv6 test: where your address is placed and who announces it

> Where your IP address is placed, which network announces it, whether IPv6 works and how your IPv6 address was assigned, next to IPv4.

## IP geolocation, ASN and dual-stack

IP geolocation maps an address to a country, region and city using a database of which networks are used where. It is a good guess, not a GPS fix: mobile and VPN addresses are often placed at the operator's hub, and the accuracy radius says how far off it may be. The ASN (autonomous system number) identifies the network that announces your address to the global routing table, usually your ISP or hosting provider.

When IPv4 and IPv6 are both available, the browser races them (Happy Eyeballs) and this view shows which one won, how their paths compare and, for IPv6, how the address was assigned: native or tunnelled, and whether the interface identifier is random or derived from a MAC address.

### How accurate is IP geolocation?

The country is right almost always, the city often, the street never. Databases record which address blocks an operator uses where, and the accuracy radius shown next to the location says how far off that may be. Mobile carriers and VPN providers route many users through one hub, so their addresses land at the hub. This page also compares the round-trip time with the distance to the claimed location, which catches placements that are physically impossible.

### Why does my IP address show a different city?

Because the database knows where your ISP uses the block, not where your router stands. Large ISPs hand out addresses from regional pools, carrier-grade NAT puts thousands of customers behind one address, and reassigned blocks take months to be updated. None of that is an error on your side.

### What is an ASN and why does it matter?

An autonomous system number identifies the network that announces your address to the rest of the internet, usually your ISP, a mobile carrier or a hosting company. It tells websites what kind of network you are on: a residential ISP looks like a person, a hosting ASN looks like a server or a VPN exit, which is why it carries weight in the verdict on the overview.

### Do I have IPv6?

If the IPv6 plate at the top shows an address, IPv6 works end to end: your browser opened a connection to our IPv6-only host and the packets arrived. The dual-stack card also shows which family your browser preferred for the main site, the Happy Eyeballs race, and how the two paths compare in round-trip time.

### Is my IPv6 address derived from my MAC address?

The last 64 bits of an IPv6 address, the interface identifier, are either random (privacy extensions, the default on every current operating system) or built from the network card's MAC address in the older EUI-64 scheme, recognisable by ff:fe in the middle. This view names which one you have; a MAC-derived identifier follows the device from network to network.

### Why do IPv4 and IPv6 show different locations?

The two addresses can belong to different networks: a tunnelled IPv6 address is placed at the tunnel broker, a mobile carrier may route the families through different hubs, and the two database entries are maintained separately. A large distance between them is worth a second look; a different city in the same region is common.

Related terms: [IP geolocation](https://ip-tools.eu/glossary.md#ip-geolocation), [Autonomous System Number](https://ip-tools.eu/glossary.md#autonomous-system-number), [BGP announced prefix](https://ip-tools.eu/glossary.md#bgp-announced-prefix), [Happy Eyeballs](https://ip-tools.eu/glossary.md#happy-eyeballs), [Interface identifier](https://ip-tools.eu/glossary.md#interface-identifier)

## Live data

Geolocation of the caller: `GET https://ip-tools.eu/api/geo`. Any address: `GET https://ip-tools.eu/api/geo?ip=203.0.113.4`.

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Canonical page: https://ip-tools.eu/network · API documentation: https://ip-tools.eu/docs/api.md · All pages: https://ip-tools.eu/llms.txt