[Tovok]

Here's some info:

http://www.cisco.com/en/US/tech/tk59...80174a5b.shtml

http://www.cisco.com/en/US/prod/coll...ite_Paper.html

http://en.wikipedia.org/wiki/Denial-of-service_attack

http://www.computerworld.com/s/artic...t_DDoS_attacks

Generally, defending against a DDoS would be something the ISP does at least some of the heavy lifting for, I would think.