Re: [DNSOP] new ANAME draft: draft-hunt-dnsop-aname-00.txt

Florian Weimer <fweimer@redhat.com> Tue, 11 April 2017 19:10 UTC

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To: Tony Finch <dot@dotat.at>, Paul Wouters <paul@nohats.ca>
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Cc: dnsop <dnsop@ietf.org>
From: Florian Weimer <fweimer@redhat.com>
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Date: Tue, 11 Apr 2017 21:09:54 +0200
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Subject: Re: [DNSOP] new ANAME draft: draft-hunt-dnsop-aname-00.txt
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On 04/11/2017 08:42 PM, Tony Finch wrote:
> Paul Wouters <paul@nohats.ca> wrote:
>>
>> Can you give me an example of deploying ANAME outside the zone APEX that
>> is not solved by allowing a CNAME to point to a CNAME (which most code I
>> think already allows anyway)
>
> https://www.ietf.org/mail-archive/web/dnsop/current/msg19909.html
>
> If you have a subdomain that needs to be a mail domain and a web site, you
> need an MX pointing at your mail server and address records pointing at
> your web server. You can't use a CNAME because they are usually different
> servers.

That's not a problem, you can have MX records at the CNAME target.

> Also, mail domains cannot in practice be CNAMEs because of the disaster of
> RFC 821 / RFC 1122 mail domain canonicalization.

I can see why this is a concern, but does current sendmail still rewrite 
the headers?  (The envelope recipient is far less problematic.)

Thanks,
Florian