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Re: [Acme] DNS challenge server steps missing detail?

Felipe Gasper <felipe@felipegasper.com> Tue, 27 November 2018 22:24 UTC

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From: Felipe Gasper <felipe@felipegasper.com>
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Date: Tue, 27 Nov 2018 17:24:26 -0500
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To: Danek Duvall <duvall@brightgate.com>
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Subject: Re: [Acme] DNS challenge server steps missing detail?
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> On Nov 27, 2018, at 3:32 PM, Danek Duvall <duvall@brightgate.com> wrote:
> 
> Section 8.4 of the ACME spec says:
> 
>    To validate a DNS challenge, the server performs the following steps:
>      1. Compute the SHA-256 digest of the stored key authorization
>      2. Query for TXT records for the validation domain name
>      3. Verify that the contents of one of the TXT records match the
> digest value
> 
> Regarding point 2, it's not explained exactly what is queried for the
> TXT records. I've not gone looking at Boulder code, but from some
> message board postings, it seems like one of the authoritative DNS
> servers for the domain is queried. It'd be nice if the spec could
> include this information, to make writing automated clients easier.

It doesn’t really need to be explained, IMO, because “query for TXT records” implies a query against DNS, which in turn implies a query against a nameserver that’s authoritative for the domain.

-FG

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