Re: [Asrg] DNS basics, was overloading server names doesn't work

Dave CROCKER <dhc@dcrocker.net> Tue, 09 February 2010 18:33 UTC

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Date: Tue, 09 Feb 2010 10:34:44 -0800
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Cc: John R Levine <johnl@taugh.com>
Subject: Re: [Asrg] DNS basics, was overloading server names doesn't work
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On 2/9/2010 9:11 AM, John R Levine wrote:
>>>>> Nope, that won't work. CNAMEs don't do a partial match.
>
>> Where did I or anyone else specify a partial match?
>
> The user thinks his POP server is called mail.btinternet.com. When he
> looks up _report.mail.btinternet.com, what do you expect to happen?

He'll get a TXT record back.  This is nothing but exactly the same mechanism 
that is used for DKIM and SRV, albeit with a different underscore subdomain.

The DNS construct of partial matching has nothing to do with this mechanism.


>>> Also 2181. I'll go see if there's a clearer explanation somewhere else.
>>
>> Normally, something finer-grained that a reference to all of 15 pages
>> would be expected.
>
> Aw, come on. If you can't find the part about CNAMEs in 10 seconds,
> you're not trying.

You are asserting a truth.  It's your obligation to substantiate it.  A broad 
reference to a 15-page document does not satisfy that obligation.

I told you I looked for it and could not find it.  Rather than berate me, all 
you have to do to settle the matter is supply the text.  From what you say, 
that's a 10-second exercise.

d/
-- 

   Dave Crocker
   Brandenburg InternetWorking
   bbiw.net