How to Use Nmap

In: #security

The most common issue with Internet systems is that they are too complex for the ordinary person to understand. Also, a small home-based system may be complex for some people. Consequently, when it comes to bigger agencies and large organizations that deal with lots of computers on the network, the complexity will increase.

Therefore, to learn which ports are open and the rules of engagement, a program called Nmap can be used. It’s a network scanning tool available for IT administrators, network administrators, systems administrators and other IT professionals. 

This vulnerability scanning program is used to scan the network that a computer is connected to and outputs a list of ports, operating systems, device names and other identifiers that can help the user know the details behind their connection status. 

Hackers can use Nmap to gain access to uncontrolled ports on a particular system. All a hacker needs is to get into a particular system and run Nmap on that system, look for vulnerabilities, and know how to exploit them. This is why IT professionals need to be on top of their game in managing risk and safeguarding their organization's network and systems against vulnerabilities. 

Advantages of Nmap 

Nmap has many benefits which make it different from other network scanning programs:

  • Nmap is open-source and free to use.
  • It will search for subdomain and Domain Name System.
  • It is used for auditing network systems as it can detect new servers.
  • It determines the nature of the service in the host and if the host is a mail service or a web server.
  • With the help of Nmap Scripting Engine (NSE), interaction can be made with the target host.
Essential Skills for Using Nmap for Network Scanning

Nmap offers a wide range of technologies to scan the networks such as TCP connect scanning, TCP reverse identification scanning, and FTP bounce scanning. It is important to start with Nmap in order to learn all these techniques. 

Why Should We Use Nmap?

As a network administrator, there is a need to check target hosts, determine occupied and free ports and perform security vulnerability scans. Whether you need to monitor a single host or multiple hosts, it offers all utilities. 

Nmap is always used for network audits. However, it can perform redundant tasks like scheduling service upgrades, managing network inventory and monitoring different uptime and downtime services. The network discovery tool can also list the status of services such as open, closed, filtered and unfiltered. 

How to Use Nmap

If you are conversant with command-line interfaces, Nmap is easy to use. Since it’s already installed on most Linux/Unix-based distributions, you just need to execute the Nmap command from any terminal. Additionally, advanced users will also be able to use Nmap with other system scripts and automated tasks.

Nmap Port Scan Command

One of the basic Nmap commands for a scan is the Nmap port scan command:

Nmap -p 80 X.X.X.X

How to Install Nmap on Windows, Mac and Linux

What will happen if your operating system does not include Nmap? You don’t need to worry about anything just read through this article. While the installation process may not be the same based on the operating system (OS) that you’re using, in most cases (Windows and macOS) it’s relatively simple.

Installing Nmap on MacOS

Mac users have an automated installer. Just run the Nmap-mpkg file to begin the installation. After a few seconds, Nmap will be ready on your macOS.

Installing Nmap on Windows

Once you download the installer, execute it and install it. The automated installer should take care of configuring Nmap for you within a few seconds.

Installing Nmap on Linux

Open the terminal and run the following commands to get Nmap installed:

  • CentOS/Fedora: sudo dnf install nmap.
  • Ubuntu/Debian: sudo apt-get install nmap.

That’s it. Nmap is now installed on MacOS, Windows or Linux.

How Does Nmap Work?

Nmap works by checking a network of services and hosts. Once they’re found, the software sends information to the services and hosts with a response. Nmap is a cybersecurity tool that reads and interprets the response that comes back and uses the information to create a map of the network. 

The map that is created includes detailed information on the operation of each port, how the hosts are connected, what is and what is not making it through the firewall and listing any security problems that occur. 

How can this be accomplished? Nmap uses a complex system of scripts that converse with every part of the network. The scripts act as communication tools between human users and network components. The scripts that Nmap uses can perform vulnerability detection, vulnerability exploitation, backdoor detection and network discovery. Nmap is a powerful software. However, there is a need to have a great deal of background knowledge to use it.

Internet security organizations can use Nmap to scan a system and know the weaknesses that exist, which a hacker may want to exploit. As the program is free and open-source, it’s one of the most used tools for scanning networks for open ports and other weaknesses. 


If you are an organization that takes cybersecurity as an important part of the company operations, you can reach out to IT professionals who can assist you to get more information about using Nmap. 

Look for a company or product that uses this technology in an effective way and ensures that the client’s data, information, network and system are safe from vulnerabilities. As an IT professional, you can check out Topia. This is a vulnerability management tool that helps CISOs as well IT managers make informed security decisions.


Photo by Fakurian Design on Unsplash

Written by Kent Weigle

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