Imagine a busy restaurant. A Denial-of-Service (DoS) attack is like someone calling in a ton of fake orders overwhelming the kitchen. The real customers can't get their food because the kitchen is stuck dealing with the fakes.

In the computer world, DoS attacks try to overwhelm a website or online service with fake traffic, like those fake orders. This overload prevents real users from accessing the service. It's like the restaurant being too busy with the fakes to serve real customers.

DoS attacks are usually temporary, but they can be disruptive and costly.