Example of a failing DNS request

I've run into an DNS issue today. I usually scan quickly the answer from dig as I'm interested in the actual A, PTR or MX only. Today the issue was different. Below in the two failing example DNS requests please note the SERVFAIL status code.

Example 1

 
dig @194.2.2.2 www.example.com A

; DiG 9.3.6-P1-RedHat-9.3.6-16.P1.el5 <<>> @194.2.2.2 www.example.com A
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 5995
;; flags: qr rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

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

;; ANSWER SECTION:
www.example.com. 86400 IN CNAME buuu.example.com.

Example 2

 
dig @194.2.2.2 www.example.com

; DiG 9.3.6-P1-RedHat-9.3.6-16.P1.el5 <<>> @83.138.151.80 www.example.com
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 55778
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

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

;; Query time: 12 msec
;; SERVER: 194.2.2.2#53(194.2.2.2)
;; WHEN: Mon Mar 25 17:41:28 2013
;; MSG SIZE  rcvd: 52

References

1. http://networking.ringofsaturn.com/Unix/dnstroubleshooting.php

Rackspace uses anycast network for its DNS servers

From the DNS FAQ on the Rackspace Knowladge site cloud_dns_faq we can read out that:

What type of DNS network does Rackspace use?


Rackspace leverages a globally distributed anycast network. Currently we have DNS servers located in Texas, Virginia, Chicago, Hong Kong, and London. Using anycast, we broadcast the IP addresses for ns.rackspace.com and ns2.rackspace.com from each location. All DNS queries will generally go to the geographically closest nameservers, giving you faster results no matter where your queries originate. Additionally, all of our DNS servers are monitored 24/7 and if an entire datacenter were to fail, or even if all of the DNS servers within a specific datacenter were to fail, the DNS queries will automatically start going to the next best location.



View Rackspace anycast DNS locations in a larger map

References
http://www.rackspace.com/knowledge_center/cloud_dns_faq