Nmap Basics

In this course, you will learn the basics of network exploration and security scanning using Nmap, the widely used and powerful open-source tool. You will learn how to scan networks for open ports, detect hosts, and perform various types of scans.

General

Fundamentals

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Understanding Network Mapping

Network Mapping is the process of discovering and visualizing physical and virtual network connectivity via nodes and interconnections. These include all hardware (e.g., routers, switches, servers, desktops), software applications, network traffic, virtual machines, and related network elements.

Network mapping is crucial to understanding the layout of your network, how different devices are connected, and how data flows between them. This information can be valuable for routine network maintenance, troubleshooting network issues, and planning future growth or changes to the network.

Importance and Uses of NMAP

NMAP, short for Network Mapper, is an open-source tool used for network discovery and security auditing. It was designed to rapidly scan large networks, but also works against single hosts. NMAP uses raw IP packets to determine:

  • What hosts are available on the network

  • What services those hosts are offering (e.g., application name and version)

  • What operating systems and version they are running

  • What type of packet filters/firewalls are in use

  • Other valuable information

Due to its versatility and power, NMAP is often a tool of choice for IT administrators and cybersecurity professionals. It can help with tasks ranging from basic network inventory and management to advanced penetration testing and network defense.

NMAP is used in a wide variety of security audits, including vulnerability scanning, intrusion detection, and even war dialing. But it's not limited to security uses - it's also a valuable tool for network troubleshooting and performance benchmarking.

Installation and Setup

Installation of NMAP varies depending on the operating system you're using. Below are the instructions for the three most common operating systems: Windows, Linux, and MacOS.

Windows:

  1. Download the latest stable version of NMAP from the official site (https://nmap.org).

  2. Run the downloaded executable (.exe) file. Follow the prompts to install NMAP, including the NMAP GUI called Zenmap, if you choose.

Linux (Debian-Based Distributions such as Ubuntu):

  1. Open Terminal.

  2. Update your package list using:   sudo apt-get update

  3. Install NMAP using:   sudo apt-get install nmap

MacOS:

  1. Install Homebrew, a package manager for MacOS, if you haven't already.

  2. Open Terminal.

  3. Install NMAP using Homebrew with the following command:   brew install nmap

Once NMAP is installed, you can run a simple command    nmap in your command line interface to see if it works. This should display the NMAP command syntax, options, and examples.

The installation process gives you access to NMAP's powerful network scanning capabilities. As you progress through this course, you'll learn to leverage these capabilities to conduct in-depth network analysis and security audits.