nanog mailing list archives

Re: Google Public DNS Problems?


From: Blair Trosper <blair.trosper () gmail com>
Date: Wed, 1 May 2013 10:12:10 -0700

8.8.4.4 is now replying SERVFAIL whereas 8.8.8.8 is suddenly working fine
again...


On Wed, May 1, 2013 at 10:07 AM, Blair Trosper <blair.trosper () gmail com>wrote:

Goes all the way up to the A root server before failing spectacularly.

Europa:~ blair$ dig +cd @8.8.8.8 google.com A

; <<>> DiG 9.8.3-P1 <<>> +cd @8.8.8.8 google.com A
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 47332
;; flags: qr rd ra cd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;google.com. IN A

;; AUTHORITY SECTION:
. 467 IN SOA a.root-servers.net. nstld.verisign-grs.com. 2013050100 1800
900 604800 86400

;; Query time: 46 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Wed May  1 10:05:46 2013
;; MSG SIZE  rcvd: 104


On Wed, May 1, 2013 at 9:58 AM, Casey Deccio <casey () deccio net> wrote:

On Wed, May 1, 2013 at 9:38 AM, Blair Trosper <blair.trosper () gmail com>
wrote:
That's all well and good, but I certainly wouldn't expect "nslookup
gmail.com" or for "nslookup google.com" to return SERVFAIL


If you set the CD (checking disabled) in the request, a response that
would normally be SERVFAIL due to DNSSEC validation failure will
return with the non-authenticated answer.  With dig the flag to add is
"+cd".  I don't know if there's an equivalent for nslookup.  For
example:

dig +cd @8.8.8.8 google.com

Casey





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