Geolocation6 min read
Why your IP address shows the wrong city
The most common question any geolocation provider gets, and why the answer is almost never that the database is broken.
Blog
Notes on IP geolocation, networking, and the data underneath them. Written for people who have to make this work in production.
Engineering8 min read
What we found in 134,000 cloud provider IP ranges
We measured how often ASN-based hosting detection misses cloud addresses. Six providers scored under 2.3%. AWS missed 15.3%.
Privacy8 min read
Detecting VPNs, proxies and datacenter traffic
Four different questions with four very different answer qualities — and why a single "VPN: true" boolean flattens all of them.
Engineering8 min read
Rate limiting by IP: everything that goes wrong
One address is not one user, one user is not one address, and rotation is cheap. What to count instead.
Networking9 min read
IPv6 for developers who have been avoiding it
The same address has many valid spellings, one user has trillions of addresses, and blocking ICMP will break you. The short version.
Geolocation7 min read
How accurate is IP geolocation, really?
Country-level accuracy is above 99%. City-level is a different story, and the number that matters is the one most APIs never return.
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