Network defense gone wrong [Update]

Some distributed denial-of-service defenses could in fact make a Web site more vulnerable. After WikiLeaks began publishing confidential communications of the U.S. State Department late last year, a spate of incidents put distributed denial-of-service attacks back in the news. These attacks can take many forms, the most straightforward of which is simply to overwhelm the targeted file server with requests. If that server can't keep up with the barrage, legitimate users are effectively shut out. An attractive defense is to employ a large number of servers at far-flung locations. Such content-delivery networks are common enough, and plugging into one isn't difficult.