Network probing with Nmap

Let’s play Jeopardy. Here’s the answer – “This network mapping tool, first released 24 years ago, caused a stir when its accurate portrayal in Hollywood films prompted organizations such as Scotland Yard to remind the public that its use is potentially illegal.” If you said, “What is Nmap?” as the question, then you have won this Daily Double. Nmap is the go-to tool for just about anyone working on networked computers. Nmap means network mapper, and it’s useful in a wide variety of disciplines outside of security: network engineering, systems administration, and so on. Nmap’s innovation is that it allows the probes that you send to be customized to a high degree, allowing for unique responses that reveal a great deal of information about the target, and even finding shortcuts through a firewall.

Nmap is the embodiment of the colloquialism Swiss-army knife, so let’s break down its key...