In message <AE105312-3108-4B0B-8445-7116B84EC428@arbor.net>, "Dobbins, Roland" writes:
On Aug 1, 2011, at 7:42 AM, Mark Andrews wrote:
Named already takes proper precautions by default. Recursive service is = limited to directly connected networks by default. The default was first changed in 9.4 (2007) which is about to go end-of-life once the= final wrap up release is done.
This alone isn't enough. There are quite a few other things folks must do = from an architectural and operational standpoint which aren't found in name= d.conf.
The real problem is that many ISP's don't do effective ingress/egress fil= tering.
Well, no. The real problem is a protocol set/implementation which lends it= self so readily to spoofing in the first place, followed (as you say) by IS= P/endpoint network inattention to anti-spoofing, followed by protocols whic= h make use of the eminently-spoofable UDP for a critical service.
And even if DNS/TCP was use by default machines can still get DoS'd because IP is spoofable. This one looks like a direct attack on the machine as there are multiple source addresses rather than a reflector attack unless they are attempting to attack thousands of sites simultaniously.
This prevents compromised machines impersonating other machines.
Concur, but see above - spoofing is the symptom, not the disease.
----------------------------------------------------------------------- Roland Dobbins <rdobbins@arbor.net> // <http://www.arbornetworks.com>
The basis of optimism is sheer terror.
-- Oscar Wilde
-- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@isc.org