This blogs explain how to use nmap for operating system or OS detection on target machine.

Nmap is one of the most important tool for information gathering. We have use nmap to collect information about live host on our network. Now the same nmap tool can be used to determine which operating system is running on the target machine. There are two system in our network Windows machine and Kali Linux. Kali Linux is installed on Virtual box inside Windows OS.

Below is the IP Address of two machine inside same network 192.168.56.0/24

1. Kali Linux : 192.168.56.101
2. Windows : 192.168.56.102

Below output shows that there 3 machines inside 192.168.56.0/24 network.

Now running nmap with operators such as -A -O and -sV to detect OS and Service version

1. -A Starting aggressive scan
2. -O  OS detection
3. -sV Service version detection

Command  nmap -A -O -sV 192.168.56.102

In the above diagram, we can see that nmap has detected Windows XP as the OS version. I am running Windows 10 so this is not 100% accurate.