How to track DNS resolution sources

Stephane Bortzmeyer bortzmeyer at
Wed Dec 3 16:56:23 UTC 2014

On Wed, Dec 03, 2014 at 05:22:58PM +0100,
 Notify Me < at> wrote 
 a message of 13 lines which said:

> I hope I'm wording this correctly.

Not really :-)

> I had a incident at a client site where a DNS record was being
> spoofed.

How do you know? What steps did you use to assert this? Answers to
these questions would help to understand your problem.

> How does one track down the IP address that's returning the false
> records ?

If it's real DNS spoofing (which I doubt), the source IP address of
the poisoner is forged, so it would not help.

The main tool to use is dig. Let's assume the name that bothers you is Query your local resolver:

dig A

Query an external resolver, here Google Public DNS:

dig @ A

Query the authoritative name servers of First, to find them:

dig NS

Second, query them (replace the server name by the real one):

dig A

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