Around the peak of the dot-com era there was a series of incidents that introduced most users to the term DDoS, or distributed-denial-of-service attack. These came to be known as the "Mafiaboy" attacks. The attacks were somewhat scary in that they brought down, one by one, the biggest and most prominent Web sites on the Internet. Every day we wondered who was next, and—gasp!—could it be us? Eventually, the site for which I wrote the most was taken down just like all the big guys.
The attacker turned out to be a (lets be generous) troubled Canadian teenager who had managed to crack groups of computers and command them in a coordinated attack against a particular site. If you could get past the basic immorality of the act, the guy did show some talent.
The most recent famous DDoS attacks have been from worms, such as MyDoom, that attack essentially political targets such as microsoft.com. Even more recently, Panda Software described the Cone.E worm, which launches an attack against www.irna.com—which is the site of the Islamic Republic News Agency, aka the official news agency of Iran.
But DoS attacks arent just for the big guys. People in the trenches say they happen all the time for all kinds of reasons. I spoke with Paul Froutan, VP of engineering of Rackspace Managed Hosting, about some of the ways they happen and techniques that can be used to stop or prevent them.