NMAP (Network Mapper) is an open-source network scanning utility mainly used for security auditing and network discovery. It can be used to detect live hosts, specific services, operating systems, packet filters and vulnerabilities on network systems (Lyons, J., 2020).
In order to scan specific hosts using NMAP, you can follow these steps:
1. Install NMAP: Depending on your operating system this can vary. For example, on Debian-based operating systems like Ubuntu, you could use the Terminal command “sudo apt-get install nmap” (NMAP, 2020).
1. Identify Targets: Once installed, the next step is to identify the specific hosts you want to scan. Hosts can be specified as an IP address (e.g. 192.168.0.1) or a hostname (e.g. www.example.com).
1. Scan the Hosts: How you scan the hosts depends on what you want to find out. For instance, if you just want to do a simple ping scan to see if the hosts are live, you can use the command “nmap -sn [host]” in your terminal.
To examine the open ports of a host, you may use the following command: “nmap [host]”.
In order to carry out a service version detection, you could use the command “nmap -sV [host]”. This will help you to find out the service and version that is running on the open ports of the host.
For OS detection, you can use “nmap -O [host]”. This would allow you to identify the operating system of the host machine. Note that for more comprehensive scans and/or more detailed results, you should run these commands as a root user (NMAP.org, 2020).
A more realistic example might be “nmap -A -T4 scanme.nmap.org” in which -A enables OS and version detection, scripting, and traceroute while -T4 is a timing template that configures the speed of the scan (Lyon, G.F., 2009).
Remember that scanning should be conducted ethically and legally; always obtain proper permission before scanning networks that you don’t own.
Sources:
Lyons, J. (2020). Kali Linux: Assuring Security by Penetration Testing. Packt.
NMAP.org (2020). NMAP: the Network Mapper. Retrieved March 12, 2022, from https://nmap.org/book/man.html
Lyon, G. F. (2009). Nmap Network Scanning: The Official Nmap Project Guide to Network Discovery and Security Scanning. Nmap Project.
