DDoS attacks: prevention is better than cure

Security experts have reminded companies worried about denial-of-service attacks that several options are available for those whose websites become targets.

Last week, the SCO Group's website was hit by a DDoS attack, forcing the company to set up another site.

A DDoS attack typically involves thousands of compromised "zombie" systems sending torrents of useless data or requests for data to targeted servers or networks.

The SCO attack was launched using systems that had previously been infected by the MyDoom virus, which contained code that instructed thousands of infected computers to access SCO's website at the same time, rendering it inaccessible to legitimate users.

Stopping the flood of traffic can be very difficult because it is coming from so many sources, said Bruce Schneier, president of Counterpane Internet Security.

"From a philosophical perspective, if the attacker's pipe is bigger than the defender's pipe, the attacker can always knock out the defender," he added.

There are several approaches companies can take to prepare for attacks such as this, said Paul Mockapetris, inventor of the internet's core domain name system and chairman of IP address management vendor Nominum.

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