Re: [Resolverless-dns] Load-balancing concerns

Jim Reid <jim@rfc1035.com> Thu, 08 November 2018 08:47 UTC

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From: Jim Reid <jim@rfc1035.com>
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Date: Thu, 8 Nov 2018 08:47:50 +0000
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To: Justin Henck <henck=40google.com@dmarc.ietf.org>
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Subject: Re: [Resolverless-dns] Load-balancing concerns
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> On 8 Nov 2018, at 08:19, Justin Henck <henck=40google.com@dmarc.ietf.org> wrote:
> 
> You'll have to forgive my ignorance - I definitely don't pretend to be an expert in any of these areas.  My understanding (please correct me!) was that generally an authoritative will return a single A or AAAA record based on a particular query, but with DNSSEC it will return an entire relevant RRSET.

Not quite. If an authoritative server is queried for the A or AAAA records for some name, it will return all the matching A (or AAAA) records. [Modulo truncated responses and TCP retries.] It won't return a single A or AAAA record unless of course there's only one of them.

When DNSSEC is used, authoritative servers return RRsets.* That's because the signature covers the RRset and the validator has to have all of the original data -- the RRset -- so that it can validate the signed response.

*That's pretty much the same as the unsigned response with the addition of some extra RRtypes for the DNSSEC special sauce.