Hello,
I believe you can enumerate cloudflare IPs via :
https://www.cloudflare.com/ips-v4
https://www.cloudflare.com/ips-v6
It's likely an overfit situation (not just resolvers), but it's something.
-tony
On 12/2/23 21:57, Arne Jensen via mailop wrote:
Always happy to help! And wauh, times flies by these days...
First of all - I completely agree with you, that several things could be
better here ;-).
Taking the four major ones, the top list, from best to worst, might be
like:
1. OpenDNS
2. Google
3. Quad 9/PCH
4. Cloudflare
Given your mention of "internal documentation", maybe there could be
something more for you to document, if you haven't already:
Google does, as mentioned previously, document their resolver
infrastructure on the Web, contrary to many others, but also with a JSON:
-> API/JSON: https://www.gstatic.com/ipranges/publicdns.json
OpenDNS is also documenting theirs, and also have PTR on the outgoing
resolver IP, but unfortunately, the PTR **doesn't always** point to one
of their OpenDNS.* domain names, which could be confusing:
Reaching OpenDNS Copenhagen:
- 146.112.135.70 (r7.compute.cph1.edc.strln.net)
- 2a04:e4c0:17::73 (r10.compute.cph1.edc.strln.net)
Reaching OpenDNS London:
- 208.69.34.73 (m53.lon.opendns.com)
- 2a04:e4c0:10::91 (r3.compute.lon1.edc.strln.net)
It is however consistent with their locations as retrieved from here:
-> Web: https://www.opendns.com/data-center-locations/
-> JSON:
https://umbrella-dns-requests.marketops.umbrella.com/api/data-center-locations
Currently, it seems very much a hit and miss, mostly miss, when reaching
any IP address with PTR records, through Quad 9. I haven't ever seen
Quad 9 document it like OpenDNS or Google.
With Cloudflare, I've never see any of their outbound resolver IP
addresses have any PTR records. I haven't ever seen Cloudflare document
it like OpenDNS or Google.
With the above possible ways to retrieve the OpenDNS and Google data,
you have the option to automate e.g. a weekly update of their resolver
addresses, if you feel for something like that in any way. ;)
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