[CentOS] how do I find out which nameserver returns a DNS query?

Brian lists at Tatorz.com
Wed Jul 9 14:51:20 UTC 2008


On Wed, July 9, 2008 10:17 am, Michael Simpson wrote:
>> Ok, sorry, let me re-phrase.
>>
>> I want to know on my own server, which of my nameservers replied to the
>> DNS
>> query. In this example 4.2.2.1 is our ISP's upstream DNS server, which
>> is
>> configured in /etc/resolv.conf - so it should technically appear there.
>>
>> But, let's say I query host1.myserver.co.za - and myserver.co.za is on
>> another server, and has ns1.myserver.co.za, ns2.myserver.co.za,
>> ns3myserver.co.za & ns4.myserver.co.za
>>
>> So, as far as I know, any one of those can reply (round robbin DNS?),
>> but I
>> would like to know which one replies for this particular dig. Is that
>> possible? I don't want to specify a server to query, I want to find out
>> which of the 4 returns the query. If it's a cached reply, does it mean I
>> won't see it?

At the end of your dig reply you will see the following..

;; Query time: 26 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Wed Jul  9 10:49:40 2008
;; MSG SIZE  rcvd: 297

That tells you which server answered the query.

HTH




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