Grabbing SSL pages puts a higher 'load per page grabbed' on the server due to the extra load of processing the encryption elements of the SLL process. It also used additional third party 'amplifiers' to multiply up the output of each individual agent. However, we find that this information is rarely acted upon because people don't take DoS attacks seriously. Conclusions Denial of Service attacks will never go away - because the 'brute force traffic storm' trick will always offer an attack route. Maybe over the next couple of years if universities and other insecure organisations that are typically used by attackers to plant their agents will tighten up on security, and make it harder for the distributed attacks to plant enough agents.
Penetration testing provides the best 'real world' picture of a site's security.
Co-ordination between ISP's is very patchy and will increase as it becomes more and more vital, for the stability of the ISP's themselves, for them to respond quickly to major brute force attacks like the Yahoo one.