nanog mailing list archives

Re: [c-nsp] DNS amplification


From: Arturo Servin <arturo.servin () gmail com>
Date: Sun, 17 Mar 2013 12:33:01 -0300


        Yes, BCP38 is the solution.

        Now, how widely is deployed?

        Someone said in the IEPG session during the IETF86 that 80% of the
service providers had done it?

        This raises two questions for me. One, is it really 80%, how to measure it?

        Second, if it were 80%, how come the 20% makes so much trouble and how
to encourage it to deploy BCP38?

        (well, actually 4 questions :)

Regards,
as

On 3/16/13 7:24 PM, Jon Lewis wrote:
On Sat, 16 Mar 2013, Robert Joosten wrote:

Hi,

Can anyone provide insight into how to defeat DNS amplification
attacks?
Restrict resolvers to your customer networks.

And deploy RPF

uRPF / BCP38 is really the only solution.  Even if we did close all the
open recursion DNS servers (which is a good idea), the attackers would
just shift to another protocol/service that provides amplification of
traffic and can be aimed via spoofed source address packets.  Going
after DNS is playing whack-a-mole.  DNS is the hip one right now.  It's
not the only one available.


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