Re: [DNSOP] abandoning ANAME and standardizing CNAME at apex

Ray Bellis <ray@bellis.me.uk> Mon, 17 September 2018 08:47 UTC

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From: Ray Bellis <ray@bellis.me.uk>
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Subject: Re: [DNSOP] abandoning ANAME and standardizing CNAME at apex
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On 17/09/2018 08:43, Mukund Sivaraman wrote:

> The suggestion is only to require support in resolvers going forward for
> CNAME co-existing with other types for now. That should not break any
> detail of how DNS is used today.

...

> Although it changes current DNS protocol, AFAICT there does not seem to
> be anything badly wrong with allowing CNAME + other types at a node,
> where the CNAME is considered a fallback when the required type doesn't
> exist.

This is not true.

Ondrej demonstrated at the last hackathon that permitting a CNAME
alongside the apex can cause MX-related failures in resolvers that are
not upgraded.

There are going to be presentations on this topic at the forthcoming
DNS-OARC meeting in Amsterdam.

Ray