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Comment by mzajc | Hacker News Reader

> The primary one is that the notion of a “UK based IP” is nonsense. Geolocation databases work by figuring out where people log in from and only after doing a lot of pattern recognition do those addresses get associated with that location.

I support the cause, but I don't think that's true. RIPE, the RIR responsible for UK, makes available a list of allocations per country. For UK:

  https://stat.ripe.net/data/country-resource-list/data.json?resource=gb

These are actual per-country allocations, not interpolations from access patterns.

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This is only "supposed to be" accurate to some definition of what country the IP is assigned to, it is not an authoritative field for where it is currently being used. Multinational corporations, M&As, georedundant failover, leasing/selling, and other events often result in this field being outdated or plain wrong. Hell, I've been able to advertise part of my ARIN assigned US IP space out of a peer in Europe. This also ignores the EU designation on certain records https://wq.apnic.net/apnic-bin/whois.pl?searchtext=94.102.16...

Edit: RIPE actually has documentation on this fallacy specifically https://docs.db.ripe.net/RPSL-Object-Types/Descriptions-of-P...

> “country:” – Officially Assigned two-letter ISO 3166 country code or "EU" (exceptionally reserved). It has never been specified what this country represents. It could be the location of the head office of a multi-national company, where the server centre is based, or the home of the End User. Therefore, it cannot be used in any reliable way to map IP addresses to countries.

Yeah, geo-IP is not perfect, but it's not built on pure guessing like the author implies.

Yeh it's the sub-country data that's often bad, not the national stuff.

Not true, IP addresses are sold on, or even from time to time IP addresses are even leased (they can be transferred from RIRs, temporarily or permanently). Some times IP address ranges are registered with RIR but used in a different geography / region.

Geo-IP databases are mostly accurate, emphasis on mostly.

And then there's the case of mobile roaming.

In the overwhelming majority of cases, mobile roaming traffic uses "home routing", not "local break-out". This means it is routed to the country where the user normally resides, not where they currently are. This means:

- For people visiting the UK (and potentially staying there for a long time, if on a permissive roaming plan), their IP address won't show up as UK despite long-term residence / citizenship.

- British people visiting other countries will still be subject to OSA, even when they should not be.

- People (including British people!) who buy British AirAlo SIMs may not get a British IP. AirAlo often uses SIMs registered in a different country than the one you're visiting, and the "exit node" (P-GW) may be located in a different country altogether. I suspect this last option will become quite attractive if VPN bans ever actually come into effect.

This is pretty much unfixable without major changes in how LTE roaming is conducted worldwide, and the UK isn't important enough to make that happen.

Is there really nowhere that you can get a non-UK IP while still being in the UK? What about along the Ireland/Northern Ireland border using a cellphone?

No edge cases, it is a matter of law.

Regrettably, the list in question offers limited operational value, as it omits the so-called «exit» CIDR's utilised by major cloud service providers – a glaring omission that renders the dataset largely superficial.

Let's, for analytical clarity, set aside the UK and examine Germany as an isolated datapoint.

AWS, for instance, possesses and operates the entirety of the 3.0.0.0/9 address space – a range distributed across numerous jurisdictions and continents. Notably, significant CIDR allocations from 3.0.0.0/9 reside within German territory, yet remain absent from the RIPE registry. Such inadvertent obfuscation undermines efforts at precise geolocation.

One may, through inference and correlation – specifically via https://ip-ranges.amazonaws.com/ip-ranges.json – arrive at a reasonably accurate estimation of the German CIDR's by aggregating address ranges tied to a designate AWS region they are associated with. Such inference is only feasible due to the vendor’s decision to publish such data. I would reasonably conjecture that other cloud providers engage in a comparable practice.

Thus, whilst it is not altogether impossible to ascertain the geolocation of a given IP address, the exercise remains contingent upon the discretionary transparency of global infrastructure operators and multiple indirect information sources – a rather fragile foundation upon which to build certainty.

The author addresses this: these IP allocation lists are rife with errors and are sometimes outdated.

This is likely why someone living in the UK was able to access one of the sites in question despite the geoIP-based ban.

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