Nmap (Network MAPper) is a network scanner written by Gordon Lyon. It is a free and open source tool and is available at insecure.org with versions for Windows and Linux and is ubiquitous in its use. Nmap can be (and is) used to for instance, scan for open ports on a remote server, to detect the OS run on the server, what all services are running on the remote server and so on. In the hands of a ethical hacker Nmap can be used for helping to audit a network but it's also used by attackers. So this brings up the question is software like Nmap ethical?

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