DDoS is short for Distributed Denial-of-Service and is used to define a certain type of attack whose purpose is to make a specific computer or server unavailable to its users by indefinitely or temporarily suspend or interrupt the services of a specific host connected to the Internet. The most popular targets of DDoS attacks are credit card gateways, financial institutions, and even government sites. The difference between the Denial of service attack and the DDoS attack is that with DDoS there are multiple systems flooding a targeted server with huge packets of data and that ensures less chance to stop the attack or to trace the root source of it. Nowadays this is the most popular attack of all existing denial of service methods.
Unintended Denial of Service
Sometimes it is possible that a web site stops working because its server is handling too many visitors’ requests. This can happen if there is a sudden and enormous spike in the popularity of a web page. It can attract a lot of traffic from social networks such as Reddit or Digg or the website may get mentioned on the TV news in the primetime. In that case, thousands of people in just a few hours will click on this link from a popular social network or will visit the web page after seeing it on TV. This will have the same effect as a targeted DDoS attack because it will slow down the web server or eventually cause it to crash due to overload. However, in this case, the server overload will not be malicious – the website will simply become a victim of its popularity.