Denial-of-service attack

A denial-of-service attack, or "DoS attack," is like when someone tries to break into your house. They keep banging on your door, or ringing your doorbell, over and over again and it never stops. With a DoS attack, someone is trying to stop you from being able to use something, like a website. They send so many requests to the website that it can't keep up, and the website gets too busy to let you visit it. It's like they're blocking the door so you can't get in.