What is Nmap?

Let's start by giving you a quick introduction as to what Nmap is. Nmap short for network mapper is a free and open source command line tool for network discovery and security assessment. It is used by ethical hackers, penetration testers, systems, administrators, black hat hackers and anyone in fact, who wants to understand more about the devices on a given network. It is also often called a network scanner or a port scanner because it scans for open ports on devices. But it has much more functionality than just a simple port or network scanner and port scanning. If you're not familiar with what that means, what that term is, well, this will tell the user of the scanner what ports are open on the scan devices and therefore what services are running, such as As you can see here, we've got Port 22 open. So we know on this device, which happens to be 192.168.1.1. That that is potentially SSH and it's given us some version information here so we can see that this is SSH or it could be port 80 and it could be Http web server or 53, which is a DNS server. So that is what a port scanner does. That is what Nmap does. It determines whether the host is up and it determines what the host is running on it. And it can do that across multiple different domain names and IP addresses. And Nmap uses raw IP packets specially crafted in order to determine this. So it tells you, as I've said, what hosts are available on a given network, what services. As we can see here, the services like the application name and the version the host that are available. In this instance, we can see 192.168.1, as I've said, and potentially what operating system we can see here, Linux, we can see here the Linux kernel and depending on the scan what type of packet filtering firewalls are in use and many other characteristics can be deemed using Nmap. Nmap also has a powerful scripting capability. It allows users to write and share scripts using the Lua Lua programming language to automate a wide variety of networking tasks, including things like network discovery, more sophisticated version detection and vulnerability detection. It can be used, the scripting can be used for vulnerability, exploitation and even brute forcing. Emma was designed to rapidly scan large networks but works fine against single host to Nmap runs on all major operating systems and official binaries are available for Linux, Windows and Mac OS X to name a few. In addition to the classic command line Nmap executable which you can see the output here. The Nmap suite also includes a gooey called zenmap, which you can see here for a graphical interface to Nmap, all of which we're going to go through on this course. So that was your quick introduction to Nmap, so let's carry on.