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

Petr Špaček <petr.spacek@nic.cz> Wed, 19 September 2018 07:05 UTC

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Date: Wed, 19 Sep 2018 09:05:21 +0200
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Subject: Re: [DNSOP] abandoning ANAME and standardizing CNAME at apex
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On 18/09/2018 22:02, JW wrote:
> 
> -------- Original message --------
> From: Mark Andrews <marka@isc.org>;
> 
>> I would also expect a relatively large client population using SRV records
>> given the rate Firefox and Chrome browsers are upgraded.  SRV lookups
>> work for lots ofother protocols.  SRV records also make it through
>> firewalls and IDS today.
>>
> 
> Hi Mark,
> 
> I agree SRV is the obvious choice for a greenfield protocol but there is
> HTTP code sprinkled /everywhere/.  I can't imagine all those forgotten
> scripts, lonely IOT devices, and troubleshooting guides are going to be
> as easy to solve as updating chrome and firefox.
> 
> Whatever the solution, I feel it should be as transparent to the client
> as possible.  CNAME would fit this bill but the negative impact is
> largely unknown.

TL;DR: Experiments with CNAME @ apex showed that it is not going to work
if the domain has e.g. MX records for e-mail.

Ondrej Sury describes his experimental results in presentation here:
https://github.com/IETF-Hackathon/ietf102-project-presentations/blob/master/dns_hackathon-presentation.pdf

Petr Špaček  @  CZ.NIC


> Perhaps defining a set of default protocols for SRV where it could
> simulate a CNAME-like response if https/http SRV records are found?
> 
> /John