Have you ever noticed that some websites can figure out, at least roughly, where you are? Sometimes they use it to find you a closer content provider. Or they might block you from seeing certain things while offering you other things specific to your location. This is possible because there are databases that map IPs to locations. [Mark Litwintschik] looks at using those databases from an API or downloading them into your own database. He also shows some very large database queries, which is interesting, too. He uses IPInfo, although there are other providers. Some only provide a limited number of lookups, but there are plenty of free tiers for low-volume usage.

The database changes every day. Of course, each provider has a different way of getting data, and so there are differences. [Mark] compares the IPInfo dataset against MaxMind’s also free database. That involved comparing over 3 billion records! Actually, the 3 billion are the number of IPs that matched up in both databases. There were an additional 118 million that didn’t match and 34 million that were not in the MaxMind database.

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