Re: [Acme] DNS challenge spec doesn't support CNAME model

Ted Hardie <> Fri, 18 December 2015 16:49 UTC

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Date: Fri, 18 Dec 2015 08:49:49 -0800
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From: Ted Hardie <>
To: Eric Mill <>
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Cc: "" <>, Andrew Ayer <>
Subject: Re: [Acme] DNS challenge spec doesn't support CNAME model
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On Thu, Dec 17, 2015 at 2:40 PM, Eric Mill <> wrote:

> On Thu, Dec 17, 2015 at 11:19 AM, Andrew Ayer <>
> wrote:
> Yes, but this forces users to do the work of adding a second CNAME that
> points to the third party service, and prevents the service from doing it
> themselves.
> The user base that would *benefit* from keeping the prefix consists of
> users who want to CNAME their domain to a service (instead of full DNS
> delegation) but who wish to obtain a cert themselves and then upload that
> certificate to the service they've CNAMEd their domain to. That user base
> sounds relatively small to me -- certainly smaller than the number of users
> who currently use (or would use) custom domain support on third party
> services.
> To me, it seems like we'll get more widespread use of ACME (and HTTPS
> adoption) by allowing large services to just "flip the switch" for
> everyone, rather than involving the user in this decision.
> So, I'm a wee bit concerned that taking the user out of the decision
entirely will leave us in a place where the user doesn't have an easy way
to withdraw approval for this.   If a user transitions from the user base
you are focused on to the one where they obtain the cert themselves, I'm
not sure how that works.

Put another way, I think we're tryin to make it easy for the user to get
what they want; we're not trying to set it up so that they're not involved
in deciding what they want.

Just my personal opinion,