A statement on Akamai's customer site said the company "is aware of a service interuption earlier today affecting content delivery. We have identified the root cause and have implemented the fix. Issues retrieving content should be decreasing or resolved." The language hints at a technical problem rather than a distributed denial of service attack (DDoS), which had been the focus of early speculation. The size of Akamai's network - reports range from 12,000 to 15,000 servers - would seem to make such an attack unlikely.
Content distribution networks (CDN) help manage high-traffic sites by caching content on a network of servers close to the edge of the network, allowing the traffic to be distributed among many servers instead of focused on a single point on the network. CDNs are also used to defend against DDoS attacks, using their networks of servers to blunt an attack's impact. Microsoft used a CDN service from Akamai to keep its web site online last August, when the Blaster worm programmed machines to launch a DDoS on the Windows Update site.
The nature of Akamai's network has earned it the attention of hackers, including the Fluffi Bunny group, which claims to have stolen files during a network intrusion in April 2001. The group reportedly hoped to use Akamai's thousands of servers in a concerted attack on the DNS system. Akamai disputed the claims and said its network was never in danger of being used in such an exploit. The assumed head of Fluffi Bunny arrested last year at the InfoSecurity Europe 2003 trade show in London.