DDoS (Distributed Denial of Service) attacks are a growing concern in todays internet world. The point of DDoS attacks is to make computer or server resources unavailable for it’s intended traffic by sending it a huge amount of external communication requests, thereby halting it’s performance. Ddos attacks can either make the service responses very slow or not at all by consuming all the server/network resources.
Ddos attacks, unlike regular Denial of service methods includes several (sometimes up to thousands) of machines attacking one target.
Bot nets are usually used by hackers to carry out Ddos attacks. Hacker infects insecure computers with worm/Ddos tool and later on orders them to start performing an attack on the server. The computer in the bot net might not even notice being the member of it as the traffic consumption is really low, thereby you might not even know your computer is being used to attack a third party system.