questions on the dig info

Lyle Giese lyle at lcrcomputer.net
Sat Jul 9 02:25:25 UTC 2011


On 07/08/11 20:07, Feng He wrote:
> Hello list,
>
>
> $ dig www.qq.com ns @ns1.qq.com
>
> ;<<>>  DiG 9.4.2-P2.1<<>>  www.qq.com ns @ns1.qq.com
> ;; global options:  printcmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 50734
> ;; flags: qr aa rd; QUERY: 1, ANSWER: 2, AUTHORITY: 4, ADDITIONAL: 0
> ;; WARNING: recursion requested but not available
>
> ;; QUESTION SECTION:
> ;www.qq.com.                    IN      NS
>
> ;; ANSWER SECTION:
> www.qq.com.             86400   IN      NS      ns-tel1.qq.com.
> www.qq.com.             86400   IN      NS      ns-tel2.qq.com.
>
> ;; AUTHORITY SECTION:
> qq.com.                 86400   IN      NS      ns4.qq.com.
> qq.com.                 86400   IN      NS      ns1.qq.com.
> qq.com.                 86400   IN      NS      ns2.qq.com.
> qq.com.                 86400   IN      NS      ns3.qq.com.
>
> ;; Query time: 7 msec
> ;; SERVER: 219.133.62.252#53(219.133.62.252)
> ;; WHEN: Sat Jul  9 08:58:38 2011
> ;; MSG SIZE  rcvd: 144
>
>
>
>
> $ dig www.qq.com ns @ns-tel1.qq.com
>
> ;<<>>  DiG 9.4.2-P2.1<<>>  www.qq.com ns @ns-tel1.qq.com
> ;; global options:  printcmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 44393
> ;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
> ;; WARNING: recursion requested but not available
>
> ;; QUESTION SECTION:
> ;www.qq.com.                    IN      NS
>
> ;; AUTHORITY SECTION:
> qq.com.                 86400   IN      SOA     ns1.qq.com.
> webmaster.qq.com. 1293074536 300 600 86400 86400
>
> ;; Query time: 7 msec
> ;; SERVER: 121.14.73.115#53(121.14.73.115)
> ;; WHEN: Sat Jul  9 08:59:07 2011
> ;; MSG SIZE  rcvd: 78
>
>
>
>
> I have two questions against the two dig info above.
>
> First, why ns1.qq.com (which is the authority nameserver for the zone
> of qq.com, not www.qq.com) returns the authority answer for
> www.qq.com's NS query? and even includes a AA flag in the response.

qq.com zone is the parent to the subdomain www.qq.com, so it has to have 
knowledge of the name servers for the www.qq.com subdomain.  That is how 
a recursive name server finds www.qq.com.

>
> Second, why ns-tel1.qq.com (which is the authority nameserver for the
> zone of www.qq.com) returns nothing for this zone's NS query?

Misconfiguration of ns-tel1.qq.com or it's not allowed to give you that 
answer.  Hard to tell from here.

The view from here does not show ns-tel1.qq.com to be authorative for 
www.qq.com.

Lyle Giese
LCR Computer Services, Inc.



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