Nmap Tutorial for Beginners

Checking Host Status and Buffer Size

How to Check Host Status and Buffer Size?

In this part of the Nmap tutorial, let’s learn how to check host status and buffer size. Here is the complete process.

  1. Open Kali Linux machine and Metasploitable2 (victim machine).

  2. In Metasploitable2, enter the username and password (msfadmin, by default) and hit Enter.

  3. Now, find the IP address of this machine by writing ipconfig command. It will show the IP address to be scanned using Nmap. In this tutorial, the IP address is

  4. Now, open the terminal in Kali Linux. Write nmap and press Enter. It will show you a lot of information about the tool and the commands available to run different types of scans. 

Here, let’s use -v -A commands with the IP address. -A is for running an aggressive scan while -v is to increase verbosity level and show the output in detail. So, run the following command:

nmap -v -A 

  1. It will take a couple of minutes and then show the output. You can observe the open ports and information related to them. For example, it is showing that FTP is in use along with its version. The scripts are also tested and the output is shown. You can find vulnerable components on the victim machine. 

  2. By default, the aggressive scan shows the output of the most common ports. In case you want to have a look at the vulnerabilities in all the ports on the victim IP address, you can define the port range in the command. The complete port range is from 1 to 65535. So, run the following command in the terminal to scan all the ports:

nmap -v -A -p 1-65535 

  1. The output will take a few minutes as the scanning is being performed on all the ports. You can observe the output and take note of the vulnerabilities. 

Like -A (aggressive scan), you can also try other commands in Nmap and check host status and buffer size.

Checking Host Status and Buffer Size

Let's understand how to check host status and buffer size with this practical video:

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