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Re: [dbound] [art] [DNSOP] not DNAME, was Related Domains By DNS (RDBD) Draft

"John R Levine" <johnl@taugh.com> Thu, 28 February 2019 01:49 UTC

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Date: Wed, 27 Feb 2019 20:48:56 -0500
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From: John R Levine <johnl@taugh.com>
To: John C Klensin <john-ietf@jck.com>
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Subject: Re: [dbound] [art] [DNSOP] not DNAME, was Related Domains By DNS (RDBD) Draft
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On Wed, 27 Feb 2019, John C Klensin wrote:
> at least one aspect of it is probably worth mentioning.  It
> requires understanding "tree" but not any special understanding
> of IDNs, variants, etc.

You don't even have to go that for.  Let's say you do this:

foo.com. DNAME bar.org.

Then www.foo.com will be an alias for www.bar.org, but DNAMEs only affect 
names below themselves, so foo.com will remain undefined, and you can't 
put a CNAME and a DNAME on the same name.  This makes it useless for what 
most people imagine they want to use it for.

There's the additional issue that an MX with a target of a CNAME or DNAME 
doesn't work reliably, and the point you made that if you've got variants, 
you can get a very bushy tree every time a variant character appears in a 
label.

This issue has been argued at great length with proposals like BNAME and 
CLONE so let's not redo it here.

Regards,
John Levine, johnl@taugh.com, Taughannock Networks, Trumansburg NY
Please consider the environment before reading this e-mail. https://jl.ly

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