Many different kinds of Denial-of-Service (DoS) attacks
are known and they constitute a recurring pattern in
the area of computer security. Especially Distributed
Denial-of-Service (DDoS) attacks, in which a large number
of systems concurrently perform a DoS attack against
a victim, play an important role [14]. The first welldocumented
DDoS attacks were observed back in the
year 1999, when a tool called trin00 was studied by Dittrich
[7]. He detected a network of more than 220 compromised
systems that was used to flood a single server
located at the University of Minnesota starting on August
17, 1999. This machine was offline for over two days
and at least sixteen other systems were also attacked by
the same DDoS network. In the following months, many
similar attacks were observed and these incidents even
received attention from the mainstream media when sites
such as for example Yahoo!, Amazon, and eBay were targeted
in February 2000.