Using Network Discovery Tool (Nmap) in Ubuntu

Nmap is one of open source network discovery tools. In Nmap, there are so many features such as Target Specification, Host Discovery, Scan Techniques, etc,... . We can also check website is up or down by using Nmap. In this example, I'l tell you some functions under Host Discovery.


How to install Nmap in Ubuntu
Open a new terminal and type sudo apt-get install nmap in it. Wait a moment until the software is successfully installed.


1. Using List Scan (-sL)

Open new terminal and type nmap -sL domain name (eg. nmap -sL tnw87.com) in it. Then you will see ip address of 'tnw87.com'. If you don't see, your domain is errored in something.


2. Using Ping Scan (-sn)

Open new terminal and type nmap -sn domain name (eg. nmap -sn tnw87.com) in it. Then, you will see '1 IP address / 1 Host is up'. If you don't see, your domain is errored in something.


3. Treat all hosts as online (-Pn)

Open new terminal and type nmap -Pn domain name (eg. nmap -Pn tnw87.com) in it. Then, you will see '1 IP address / 1 Host is up'. And the services of http, https, http-proxy, https-alt are needed to be in open state. You don't see those conditions, your website is errored in something.

There are still so many features in Nmap. Open new terminal and type nmap in it and press enter. Then, you will see so many features. You can try those yourself.