Known for a long time, Distributed Denial-of-Service
(DDoS) attacks are still prevalent today and cause harm
on the Internet on a daily basis. The main mechanism
behind this kind of attacks is the use of so called botnets,
i.e., networks of compromised machines under the
control of an attacker. There are several different botnet
families that focus on DDoS attacks and are even used to
sell such attacks as a service on Underground markets.