We are talking about the same thing (wildcard DNS records).
Examples: sleevi.example.com CNAME vdomain.com *.example.com CNAME vdomain.com <rnd>.example.com CNAME vdomain.com The BRs permit verification of each of these by establishing control over vdomain.com (under the definition of authorization domain name). If *.example.com can be verified this way, what is different between verifying *.example.com and <rnd>.example.com to verify all sub domains of example.com? All the RND does is make it so the website doesn’t have to point to vdomain.com. Jeremy From: [email protected] [mailto:[email protected]] On Behalf Of Ryan Sleevi Sent: Friday, September 2, 2016 4:05 PM To: Jeremy Rowley <[email protected]> Cc: [email protected] Subject: Re: [cabfpub] CNAME-based validation Jeremy, Perhaps it wasn't clear, I wasn't speaking of wildcard certificates, but wildcard DNS rules, in which all requests for a given subdomain return a preconfigured record type. While for TXT and CAA records this is quite uncommon, it's exceedingly common to have CNAME records. That is, both <rnd>.example.com <http://example.com> and sleevi.example.com <http://sleevi.example.com> may both CNAME to example.com <http://example.com> , by virtue of of the host putting a rule of "*.example.com <http://example.com> 3600 CNAME example.com <http://example.com> " I am attempting to assert that placing the <rnd> in the subdomain is insufficient proof of authorization, and is meaningfully and tangibly different than the proof of control demonstrated in 3.2.2.4.7. As I read your wording, it suggests the following: CA looks up <rnd>.example.com <http://example.com> <rnd>.example.com <http://example.com> points to example.com <http://example.com> CA sees it previously issued a certificate for example.com <http://example.com> using one of the other methods CA issues certificate for <rnd>.example.com <http://example.com> That concerns me. Peter's rewording suggests the inverse: CA looks up _certvalidation.example.com <http://certvalidation.example.com> _certvalidation.example.com <http://certvalidation.example.com> points (CNAMEs) to <rnd>.validation.[nameofca].com CA issues certificate for example.com <http://example.com> This is much less concerning. Could you help clarify which you intend, and for what names/purposes? On Fri, Sep 2, 2016 at 2:52 PM, Jeremy Rowley <[email protected] <mailto:[email protected]> > wrote: Wildcard domains are already allowed. We can verify Wildcard DNS because a CNAME for *. <http://domain.com> domain.com is pointing to a record previously verified. This verification method is permitted under the definition of Authorization Domain Name (where the FQDN returned by a CNAME lookup can be used to verify the requested FQDN). Although <rnd>. <http://domain.com> domain.com isn’t necessarily distinguishable from *. <http://domain.com> domain.com, the validation ends up being the same because either its considered an Authorized Domain Name (under the definition) or it was validated as a random value in this new method. For example: *. <http://domain.com> domain.com -> <http://dcv.example.com> dcv.example.com (validated under the Authorized Domain Name section) <rnd>. <http://domain.com> domain.com -> <http://validation.example.com> validation.example.com (validated under this new section) Because each is validated properly, tracking which exact section was used in the validation isn’t necessary. Jeremy From: Ryan Sleevi [mailto: <mailto:[email protected]> [email protected]] Sent: Friday, September 2, 2016 3:28 PM To: Jeremy Rowley < <mailto:[email protected]> [email protected]> Cc: <mailto:[email protected]> [email protected] Subject: Re: [cabfpub] CNAME-based validation
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