DoS stands for “Denial-of-Service”. DoS attacks aim to make a target resource unreachable or incapable of handling its standard tasks like serving clients or performing operations. Typically this is done by overloading the target with superfluous requests. A distributed denial-of-service (DDoS) attack is similar, but involves launching the attack from many different sources, thus making it harder to nullify the attack by blocking its one source of origin.