Huusker writes "Steven Bellovin and others at ATT Research Labs and ICIR have come up with mechanism to stop DDOS attacks. The idea is called Pushback. When the routers get flooded they consult a Unix daemon (/etc/pushbackd) to determine if they are being DDOS'ed. The routers propagate the quench packets back to the sources. The policy and propagation are separate, allowing hardware vendors to concentrate on the quench protocol while the white hats invent ever more clever DDOS detection filters for /etc/pushbackd. The authors of the paper have an initial implementation on FreeBSD."