Both companies averted outright network outages. One of Netcraft’s performance data collectors is hosted at Rackspace, and one can see that although Rackspace’s own site was intermittently inaccessible from different places on the Internet, transit for Rackspace customer machines to, for example, Cable and Wireless, Verio and British Telecom was unaffected during the attack.

Rackspace and Rackshack are two of the largest hosting companies, collectively accounting for around 2.5% of the Internet’s active web sites, and a successful attack on either of their networks would be very disruptive.