Denial of Service Attack

The Denial of service attack prevents legitimate internet users from accessing their targeted computer systems, devices or any other network resources.  An attacker may temporarily or permanently disturb the services of a host connected to the internet by flooding the targeted machine or resource with too many requests. The network or the server tries to authenticate all those requests, but the maliciously sent requests don’t possess a valid return address, thus making the server to wait for closing a connection.  Hence the denial of service attack keeps the server or the network busy with unnecessary traffic.