A distributed denial of service (DDoS) attack against DynDNS is causing many major websites inaccessible which include Twitter, Reddit, Tumblr, New York Times, Boston Globe, PlayStation Network and more reportedly inaccessible.

DDOS stands for Dedicated Denial of Service and this occurs when a website gets more hits than it can handle. One way of attacking a website is to flood it with requests, so a DDOS occurs. According to Dyn DNS, the attack started at 11:10 UTC, 21st October and it targeted its managed DNS service.

The DynDNS is used by many websites as their upstream provider and these websites are down on Friday morning. The websites in question are either completely down or partially down today. While the people who performed this attack are unknown, The Next Web suggests the fact that they were able to take down some of these big websites does say volumes about the ability these people have.

The incident marks a change in tactics as DDoS attacks are more typically aimed at a single site. DynDNS acts as a directory service for huge numbers of firms that helps their customers keep global address books up to date with the location of their domains.

It’s unclear who is responsible for the DDoS attack, but given the widespread nature of the attack, it seems safe to assume that these folks are no amateurs.