North American Network Operators Group
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Re: DDos syn attack

  • From: Sean Donelan
  • Date: Wed Jan 01 23:51:59 2003 
On Wed, 1 Jan 2003, Avleen Vig wrote:
> Tracing back an IP from bind logs to see which name servers looked up an
> attacked address immediately before the attack started. This at leads to
> the offender's ISP which is a good start.

Relatively few people restrict the use of their name servers to only
local users.  More folks have been getting DNS servers from DHCP/Radius,
but there are still a lot of users with hard-coded resolvers.  There may
be a few DNS resolvers which keep track of query sources, but more than
likely you'll end up at another dead-end because the true source will be
somewhere else.

Let's add port 53 to the every growing list of ports to block.