full-disclosure - Re: recursive DNS servers DDoS as a growing DDoSproblem

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Date: Wed Mar  8 19:58:35 2006
From: gboyce at badbelly.com (gboyce)
Subject: Re: recursive DNS servers DDoS as a growing
	DDoSproblem

On Wed, 8 Mar 2006, Security Lists wrote:

> Sorry, I don't see this as amplification in your example, because YOUR dns 
> servers are 100% of the traffic.  1:1 ratio.

Once the first request to the nameservers is made, the object should be 
cached by the nameservers.  Instead of one packet to each server, consider 
a stream of packets to each server.  The recipient will recieve a stream 
of 100K answers with likely only 200K of traffic back to the attackers DNS 
server.

Or better, find some random authoritative nameserver with a big DNS 
record, and then a very small portion of the attackers traffic is used and 
it is less likely to be tied back to the attacker since they don't own the 
record being requested.