nanog mailing list archives

Re: DHCPv6, was: Re: IPv6 Finally gets off the ground


From: Jeroen Massar <jeroen () unfix org>
Date: Tue, 17 Apr 2007 01:16:21 +0100

Chris L. Morrow wrote:
[..]
the STSN devices? or 'ibahn' ? One thing to keep in mind is that the
DNS-LB used by Google/yahoo (in the examples above) seems to be returning
a CNAME for AAAA queries, then nothing for the follow-up resolution
request for a AAAA for the CNAME... So, ipv6 things may look 'broken'
because they are also 'slow' (waiting to re-do much of the lookup path to
get the A version)

(snipped for brevity)

8<-------------------------------------------------------------------
$ dig @ns1.google.com www.google.com aaaa

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 41689
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 7, ADDITIONAL: 7

;; ANSWER SECTION:
www.google.com.         604800  IN      CNAME   www.l.google.com.

$ dig @ns1.google.com www.l.google.com aaaa

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 44383
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 7, ADDITIONAL: 7
------------------------------------------------------------------->8

8<-------------------------------------------------------------------
$ dig @ns5.yahoo.com www.yahoo.com. aaaa

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 3095
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 13, ADDITIONAL: 0

;; ANSWER SECTION:
www.yahoo.com.          300     IN      CNAME   www.yahoo-ht3.akadns.net.

$ dig @eur1.akadns.net www.yahoo-ht3.akadns.net. aaaa

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 15024
;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
------------------------------------------------------------------->8

The Yahoo redirect is out of bailiwick and thus requires a full lookup
again, the google one at least can be served by the same box.

But for the rest it all seems pretty fine to me...

or do you mean that those ibahn things see "NOERROR" and then no
answers, thus wrongly cache that as label has 0 answers at all?
or what I mention above with the redirect?

Greets,
 Jeroen


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