Nmap, a free open source utility used for network discovery, administration and security Auditing. Today organizations are using networks which are complicated to understand if tried manually. Nmap automates our task and helps in digging deeper into the network. It can be called a Swiss Army Knife because of its various options and to learn all the options it may take a lot of time. So through this talk, I will be covering all important options which a network security tester should know i.e from explaining target expansion basics for novices to detailing port scanning, os fingerprinting, timing performance, evading firewall and others such as Nmap Scripting Engine. We will also be learning about the phases of Nmap.