Denial of Service attacks

According to the article “Security Problems with the Internet Architecture” , there are many types of different Internet attacks and Denial of Service (DoS) and Distributed DoS (DDoS) are probably the most popular of them. While surfing the Internet we can find many sources with detailed description of these attacks.

Why are they so popular? DoS attacks do not need any technical skills for hackers. Take as an example the article “Online Attack Silences Twitter for Much of Day” (http://www.nytimes.com/ 2009/08/07/ technology/ internet/07twitter.html). Attackers overwhelmed a Web site by sending it a huge amount of junk requests. According to the analysts, this web service disruption was not caused by computers in botnet. Rather, millions of people received spam email with links to Twitter, and clicking on these links users overwhelmed the Internet site by sending too many requests for access.

I believe that mentioned above article about Twitter is relevant because it clearly shows two Internet attacks. The first one happened when users received spam letters, and in this moment mail servers were overwhelmed and bandwidth capability was decreased by millions usefulness emails. The second attack with junk requests led to the Twitter unavailability during some hours.