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How do they know which DNS a client is using?
by djbusby 3y ago
How do they know which DNS a client is using?
- MallocVoidstar 3y agoThey run their own DNS and if a request comes from Cloudflare's servers return garbage.
- kccqzy 3y agoThey require EDNS client subnet which is not supported by Cloudflare. Cloudflare's decision not to support it and the resultant breakage are mentioned in the Wikipedia article. https://en.wikipedia.org/wiki/EDNS_Client_Subnet https://en.wikipedia.org/wiki/EDNS_Client_Subnet
- scheme271 3y agoArchive.is requests EDNS information about the subnet that your system is on. Cloudflare doesn't pass this information along since it can be used to determine your location in part. So when archive.is doesn't get the subnet info, it sends bogus dns results back and you get that error. See https://jarv.is/notes/cloudflare-dns-archive-is-blocked/ https://jarv.is/notes/cloudflare-dns-archive-is-blocked/ for all the details.