[dns-operations] dns loop

Edward Lewis Ed.Lewis at neustar.biz
Tue Jun 6 22:21:09 UTC 2006

At 21:19 +0000 6/6/06, Paul Vixie wrote:

>but this is a protocol/implementation topic not an ops topic?

Being that this is 6/6/6, I'll turn this into a slightly operational topic.

 From a v6/v4 enabled network (the NANOG network), I tried to ping the 
four servers for 225.in-addr.arpa (looking for IN PTR).

ns.isi.edu.     NXDOMAIN
nic.near.net.   Referral to root
flag.ep.net.    no answer
strul.stupi.se. no answer

Turning off v6 abilities on my machine:

ns.isi.edu.     NXDOMAIN
nic.near.net.   Referral to root (lame)
flag.ep.net.    NXDOMAIN
strul.stupi.se. NXDOMAIN

Using a 9.3.0 dig.  Oh, wait, if I use 9.3.2. dig, I get 3 NXDOMAINs 
and 1 lame.  (I forgot that from 9.3.0 -> 9.3.2 dig added the ability 
to slip back to v4 if v6 failed.)

Looking further at flag.ep.net - I can traceroute6 to it, but can't 
get a DNS response from it on v6.  As in:

sh-2.05b$ ~/Documents/DNS/bind-sources/9/bind-9.3.2/bin/dig/dig IN PTR -4 @flag.ep.net

;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 27843

sh-2.05b$ ~/Documents/DNS/bind-sources/9/bind-9.3.2/bin/dig/dig IN PTR -6 @flag.ep.net.

;; connection timed out; no servers could be reached

Edward Lewis                                                +1-571-434-5468

Nothin' more exciting than going to the printer to watch the toner drain...

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