[dns-operations] Signaling client protocol to authority

Edward Lewis Ed.Lewis at neustar.biz
Mon Jan 17 15:45:20 UTC 2011

At 21:29 -0500 1/16/11, Patrick W. Gilmore wrote:
>>>  From: Dan Collins <en.wp.st47 at gmail.com>

>>>  It isn't the job of a DNS server to decide what the DNS client
>>>  actually wants.
>>  +1.
>It is not the job of a DNS server to do anything except what the 
>person configuring it tells it to do.

Both of you are right.

First, within the DNS protocol, the server can't guess what the 
client is really asking for.

Second, external to the DNS protocol, the "owner of the domain" can 
tell the server to answer based on various criteria.

I am splitting hairs this way.  A server shouldn't try to determine 
if the client can or can't do IPv6 based on how or when or why a 
query is received.  But a name server can be told "if they query came 
from some address range, or (assuming the client-IP EDNS0 proposed 
option) if the query's origination is reported to be in this address 
range, then answer $this way."  The former is an example of trying to 
put intelligence in the name server, which means more code in the 
wrong place.  The latter is an example of putting intelligence in the 
provisioning or the answer synthesis of the name server, or putting 
code in the right place.

Edward Lewis
NeuStar                    You can leave a voice message at +1-571-434-5468

Jan 11, 2011 - Either it's 1/11/11 or 11/1/11,  "Junior Saint Broadcast day"
(Nov 11 is senior...)

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