Nmap—The Network Mapper

This chapter focuses on the top Center for Internet Security‐recommended set of actions that all organizations should take. The first is the inventory and control of hardware assets, and the second is the inventory and control of software on those assets. In any size network but especially large, dynamic networks, it is vitally important to break down the complex networks and analyze traffic, facilitate issues, and fix connection problems. Network scanning is a process of finding assets that are alive or have a heartbeat, communicating and then gathering as much vital information about those assets as possible. Network scanning can be divided into four stages: network mapping, open ports, services running, and operating systems. Network mapping uses a process to discover and visualize assets by actively probing them. Nmap sends TCP and UDP packets to a targeted machine. Zenmap is the graphical user interface of Nmap. It is a multiplatform, free, and open source application.