Distributed Denial of Service (DDoS) and Denial of Service (DoS) is when attempts are made to make the system or network inaccessible. This is done by sending more traffic than the networks (or parts of the network) or systems are capable of receiving. It can also be done by sending “incorrect” traffic that exploits vulnerabilities in the system. The systems or networks usually return to normal operations when the attacks ceases. The difference between DDoS and DoS is that DDoS is an attack that is sent from many places at once while a DoS can be sent from one system in one location.