When dns-01 Validation is done, how does Let’s Encrypt do the validation behind the scenes. My assumption is that it does the following: Query for list of Authoritative name servers using NS-Records Poll Each of the servers given for an appropriately named TXT record If challenge key is found on …

It uses an off-the-shelf recursive DNS server. To be more specific, Unbound . (With a particular configuration, with DNSSEC and so forth enabled, and caching minimized.) The CA software, Boulder , doesn't do anything complicated. It just makes a TXT query to the resolver (using miekg's dns client). …

How does DNS Validation work behind the scenes

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How does DNS Validation work behind the scenes

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