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Re: How to track DNS resolution sources


From: Notify Me <notify.sina () gmail com>
Date: Thu, 4 Dec 2014 15:23:13 +0100

Hi Nick and List

Yes it's possible. The dud DNS response in some parts of the internet was
the public IP address being used by their proxy server. I'm not sure what
the proxy is, but it's a windows box. I was going to try to dig trace but
by then the poisoning  suddenly stopped happening. Any other ideas on how
to deal with this ? What can I proactively do in case it happens again?

On Thursday, 4 December 2014, Nicholas Oas <nicholas.oas () gmail com> wrote:

Is it possible that your client site has a helpful firewall that is
performing DNS doctoring?

http://www.juniper.net/techpubs/en_US/junos12.1/topics/concept/dns-alg-nat-doctoring-overview.html

The first time I encountered this neither myself nor my customer expected
it. We upgraded the firewall and suddenly their external hostname
resolution was coming back with internal IP addresses, as defined by the
firewall's NAT table.

Note this only really happens with NAT. If the spoofed records are
internal its most likely something else.

On Wed, Dec 3, 2014 at 11:22 AM, Notify Me <notify.sina () gmail com
<javascript:_e(%7B%7D,'cvml','notify.sina () gmail com');>> wrote:

Hi!

I hope I'm wording this correctly. I had a incident at a client site where
a DNS record was being spoofed. How does one track down the IP address
that's returning the false records ? What tool can one use?

Thanks!




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