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Ask HN: How does my new ISP "leak" my geolocation?

by thisislife2·2y ago·9 comments·view on hn ↗

Since I moved to a new ISP, I've noticed that both Google and Amazon are now able to better geolocate me (Amazon even lists the correct pin / zip code). With my older ISPs, Google and Amazon sometimes even listed other cities or wrong pin / zip code within my city. I have disabled geolocation on both my browser and os (with a firewall) and don't believe that is the source. Moreover, I tested with a cellular hotspot connection too (which is from a different company) and Google and Amazon aren't able to determine the location accurately with them, as they do with my wired ISP. So what could my new ISP be doing different that it "leaks" my geolocation so accurately?

9 comments

ISPs routinely sell/share geolocation data for fixed infrastructure; there are many factors that could impact why this is more accurate.

In a sparesly populated area, using microwave, point-to-point radios? You very well may be the only subscriber on that first hop from your home network, and that first hop is likely in a geolocation database (this is certainly the case for my cousins farm).

In a densely populated area? Like a residential tower with 100 units? Your next hop off your home network might be on-prem equipment from your ISP that resides in the telecoms closet in your building, which is also in a geolocation database.

There is a broad spectrum of accuracy between these, and it's big business to effectively geolocate users, mostly for advertising, sometimes for compliance, and generally not to the benefit of users :P

I am not aware of ISPs selling geolocation data in India (will have to look up on that). Yes, my building does have a common on-premise ISP equipment to which all our routers connect.

Note that this may not, and probably does not include customer location data in most jurisdictions. They sell the locations of the equipment they own, which more or less effectively correlate with customer location as I described in my previous comment.

There are tools such as https://ipapi.is/ that can be used to geolocate any IPv4 and IPv6 address in the world. Sometimes those tools are not extremely accurate, but usually they are accurate to the city level.

I know about geolocation by IP address. But as I mentioned, geolocation based on my previous ISPs IPs were never this fine-grained. What could my current ISP be doing different from these other ISPs?

Is it a local/regional ISP? Do you have a static IP with them?

Either of those can factor-into relative accuracy of geolocating your public IP

It's a national ISP, and not a small one. And no, IPs are not static and dynamically allocated each time I connect.

they're still probably assigning them regionally (I know Spectrum and Comcast do)

You mean something other than "your new ISP shares your location with Google & Amazon"?