Comment by Symbiote | Hacker News Reader

Comment by Symbiote | Hacker News Reader

Why are Cloudflare still sharing IPv6 addresses, when there should easily be enough for one per website? (And then with correct reverse DNS.)

The linked site [1] has a download of 134k hostnames. Filtering for the Cloudflare prefix, 2400:cb00:2048, there are still plenty of sites sharing an IP. For example, www.monolith.agency (a design agency) is on the same IP as www.bobshouseofporn.com (porn).

Maybe the same company hosts both websites, and it's not Cloudflare's issue, but that seems unlikely for a US porn site, Quebec design agency, Brazilian health site and Spanish programming site.

Google have 13,000 sites on the same IP, 2607:f8b0:4005:808::2013, looks like Blogger.

[1] http://www.employees.org/~dwing/aaaa-stats/

Something like:

    egrep --only-matching 'IPv6.+?  ' ips | sort | uniq -c | sort -n | grep 2400:cb00:2048

    monolith.agency has address 104.28.8.19
    monolith.agency has IPv6 address 2400:cb00:2048:1::681c:813

Notice that the IPv4 address is embedded in the last 32 bits of the IPv6 address. I would assume that this allows both addresses to be generated from the same configuration, rather than trying to keep two copies in sync.

As far as I know having very large numbers of IPs on a system can cause trouble with normal network stacks. Why do you want an individual IP address?

Why not? Seems like a nice easy privacy win.

The design agency website might get blocked as collateral by a poor filter, which knows of the porn site.

I can imagine a government that would enforce that ISPs block adult sites by default (a specfic government comes to mind), and as those sites would both use HTTPS (as websites do), the design agency's website would be blocked by default as collateral damage.

"Sorry, your website is blocked by default on all ISPs. It's to protect the children."

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