Scanners are important to Internet security because they reveal weaknesses in the network.
System administrators can strengthen the security of networks by scanning their own networks.
The capability to test those services for known holes. There are various tools available for Linux system scanning and intrusion detection. I will explain some of the very famous tools available. I have divided the scanners into three categories viz. Intrusion Scanners Host scanners Host scanners are software you run locally on the system to probe for problems.