DNS requests from

  A good way to reduce this is to turn off recursion for
people not on your network for your dns server. This is fairly easy
to do with bind8/bind9.

The attack isn't via recursive lookups (though recursion could help augment
the attack). The reflection is in terms of the DNS reply to the purported
requestor (really the victim). At lbl.gov, none of the requests result in
further lookups from our nameserver. But the victim still receives the reply
stream, which from a combined large number of name servers is very large.

See my draft paper


for a discussion of reflector attacks.


I am still curious as to why *this* attack would even exist (seeing that it
uses a spoofed source IP address) if people were filtering traffic that were
originationg from their networks properly.

I thought we discussed this already last month on the list.