[Pdns-users] NSATC.net microsoft problem last week - did you notice?

[Laurent Papier]

Le Fri, 3 Aug 2007 15:45:51 +0200
bert hubert <bert.hubert at netherlabs.nl> écrit:

Hi,

> Last week something strange happened with 'nsatc.net', the domain that
> powers many of Microsoft's services.
> 
> This affected the PowerDNS Recursor, which caused 'windows update' to be
> unavailable for many users behind a PowerDNS Recursor.
> 
> Did anybody analyse what happened exactly? By the time we were looking into
> the problem it was gone already. It may have been very brief.
>
> Please let me know if you saw this problem, and if you did any analysis what
> might've caused it.

I also noticed this. After digging the cache content of my DNS, I have found
that nsatc.net only have one NS entry in my cache and that entry did not reply
to DNS request. Removing nsatc.net entries from my cache resolve the issue
(rec_control wipe-cache nsatc.net).

A partial sample of a 'dig a www.hotmail.com'
; <<>> DiG 9.2.3 <<>> a www.hotmail.com
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERFAIL, id: 40247
;; flags: qr rd ra; QUERY: 1, ANSWER: 5, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;www.hotmail.com.		IN	A

;; ANSWER SECTION:
www.hotmail.com.	3560	IN	CNAME www.hotmail.com.nsatc.net.

;; Query time: 0 msec

I guess that someone did a mistake when they changed nsatc.net NS entries. This
wrong/partial configuration propagated to some DNS resolver depending of the
TTL expiration until the nsatc.net zone was fixed. 

-- 
Laurent Papier - 03 88 75 80 50
Admin. système - SdV Plurimedia - <http://www.sdv.fr/>