This recording is from the Open Forum ISC meeting of February 14, 2013.
After that we transitioned into the question and answer portion of the meeting, discussing first the issue of OpenDNS being used to aid in DoS and DDoS attacks, as well as what defenses exist against DDoS attacks.
The use of web crawlers in reconnaissance and how to defend against them was briefly mentioned.
There were three diagrams referred to, below are their recreations. Aside from below, they can also be seen in the video during the relevant segment.
Properly working DNS (click for full size).
DNS being abused for DoS attacks (click for full size).
DDoS from a high level (click for full size).
No slides - see images above for recreations of the white board drawings.