Are we really this helpless? (Re: isprime DOS in progress)

Danny McPherson danny at
Sat Jan 24 04:53:32 UTC 2009

On Jan 23, 2009, at 9:10 PM, Christopher Morrow wrote:

> On Fri, Jan 23, 2009 at 10:31 PM,  <Valdis.Kletnieks at> wrote:
>> On Fri, 23 Jan 2009 18:33:14 PST, Seth Mattinen said:
>>> Back to my original question: is there really not a better solution?
>> Well, we *could* hunt down the perpetrators, pool some $$, and hire  
>> 3 or 4
>> baseball-bat wielding professional explainers to go explain our  
>> position to
>> them.  Figuring out how to do so without breaking any laws is the  
>> tough part...
> Step one, find a device on your netowrk seeing the traffic
> step two, follow the stream(s) of traffic back to its ingress
> (hopefully a customer link on your network)
> step three, watch for associated traffic to the source of the dns
> queries, correlate this with other sources on your network to
> find/identify the control point for this effort.

You missed one..  Step 4: enable BCP 38 or similar
ingress source address spoofing mitigation mechanism
on all customer ingress interfaces (note: uRPF *loose*
mode no-fixie these attacks) - as you should have had
in the first place such that you didn't have to trace
those spoof packets step-by-step back through your

No more excuses, people..


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