The Triangulation Myth
In movies, hackers "triangulate" a signal in real-time. In reality, IP geolocation is much more boring (but effective). It relies on massive databases maintained by companies like MaxMind, IP2Location, and Google.
Where the Data Comes From
These databases are built using:
- Regional Registries (RIRs): Organizations like ARIN dictate which block of IPs belongs to which ISP in which country.
- User-Submitted Data: When you use a GPS-enabled phone on Wi-Fi, Google maps that Wi-Fi network's IP to your GPS coordinates.
- Latency Measurements: By pinging an IP from known locations, algorithms can estimate its physical location based on the speed of light.
Accuracy Limits
IP geolocation is roughly 95-99% accurate at the country level, but only 50-80% accurate at the city level. It's great for knowing if a user is in the UK or US, but it might guess the wrong neighborhood in London.