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Re: [DNSOP] Validating responses when following unsigned CNAME chains...

Brian Somers <bsomers@opendns.com> Thu, 30 April 2020 16:00 UTC

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From: Brian Somers <bsomers@opendns.com>
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Date: Thu, 30 Apr 2020 09:00:00 -0700
Cc: Brian Somers <bsomers@opendns.com>, Shumon Huque <shuque@gmail.com>, "dnsop@ietf.org WG" <dnsop@ietf.org>, Michael StJohns <msj@nthpermutation.com>
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References: <1EA6A13C-6E60-4ED9-9A50-E33D9D17504C@fugue.com> <129b0546-0123-30e0-cfca-8a66721ab046@nthpermutation.com> <CAHPuVdU0BkdWszQs0cAE0N2AA9cqJfO=aA70GsmyWw7Hzeb6Cw@mail.gmail.com> <58C18901-494E-4C2C-9C0D-746D9B08FA5A@opendns.com> <B5B438D8-D3A7-41B2-859F-AC7A94031135@fugue.com>
To: Ted Lemon <mellon@fugue.com>
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Subject: Re: [DNSOP] Validating responses when following unsigned CNAME chains...
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On Apr 30, 2020, at 8:17 AM, Ted Lemon <mellon@fugue.com> wrote:
> 
> On Apr 29, 2020, at 11:38 PM, Brian Somers <bsomers@opendns.com> wrote:
>> Furthermore, the CNAME alias RRset must be validated unless the CD bit is set.
>> A validating resolver MUST validate and can only return RRsets if they are proven
>> to be either insecure or secure.  If the aliased RRset is bogus, the answer is
>> SERVFAIL.
> 
> Ah. I like this answer. Is there a place where this is stated in the RFC that we can point to?
> 

I would say RFC 4035 sections 4.2 and 4.3 say this.  Section 5.5 re-iterates that
SERVFAIL should be sent if signatures don’t validate.

—
Brian

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