Bugtraq mailing list archives

RE: recursive DNS servers DDoS as a growing DDoS problem


From: "Thomas Guyot-Sionnest" <Thomas () zango com>
Date: Tue, 4 Apr 2006 07:40:01 -0700

-----Original Message-----
From: Geo. [mailto:geoincidents () nls net] 
Sent: April 2, 2006 10:31
To: bugtraq () securityfocus com
Subject: Re: recursive DNS servers DDoS as a growing DDoS problem

1. Resolvers and Authoritative nameservers must be separate and
authoritative nameservers must have recursion turned off. Otherwise
there is no way to throttle only recursive queries.

Great, for small ISP's you just doubled the number of 
machines they need to
dedicate to DNS.

They can run both recursive and authoritative DNS on the same server using
different IP address.

2. In a smaller ISP the nameservers themselves can get an 
aggregate of
the ISP routing table and have internal routes tagged accordingly so
that the DNS server can throttle them. No rocket science there, the
provisions are already available in every single OS in use as a DNS
server in ISPs/Telcos. All this requires is a moderate level of
competence in the person who has designed the service.

Really? Ok educate me, how do you do this with Windows 2000 
running MS dns?
(telling people to use another server is not acceptable)

Geo.


If Microsoft's products are broken, why souldn't I tell people to use
something else?

Thomas

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