What is Nmap?
Its a tool. A security scanner that is used to scan open ports, discover host and service that are running on the connected network.
Its an open source. Its used for active and passive foot printing.
If you have heard footprinting for the first time and don’t know what it is let me tell you what is footprinting and its type.
Footprinting is a technique to gather information about system or the target. There are two type of footprinting
1. Passive : Data is collected without owner’s knowledge. Ex:Google, Job portals,Social media, etc
2. Active : Data is collected by interacting with owner or someone who works for the organisation also known as Social Engineering. Ex: talking with former employee of the organisation or calling receptionist and impersonating as employee who lost his access card or forgot his login credentials, etc.
Now let me show you how to scan in nmap for particular ip.To know ip you can write ifconfig in linux and in windows type ipconfig.
1. This is simple ip scan in nmap
‘nmap (ip address)’ -> Nmap 192.168.225.62
Note: 192.168.225.62 is my ip address.
Now let me try with other ip that I have connected to the same network
So this time ip address will be changed ’nmap 192.168.225.159’
So the result will be as shown in image.Note that there is table which shows ports open and services running on that port
And also if u are in the same network it will show the Mac address of the device.
2. Now lets say that there are multiple IP address on the network that u want to scan then you can write this command
‘Nmap <IP address> <IP address> <IP address>’
Nmap 192.168.225.62 192.168.225.159
OR
You can just write all the IP address in one file and just call that file on the nmap command
‘Nmap -iL <filename.txt>’
nmap -iL /root/Desktop/test
3. Now lets go with Aggression scan.
In Aggression scan you will get to know the OS used and its version and also scripts running and also trace route scan
‘Nmap -A <Target IP address>’ i.e, nmap -A 192.168.225.159
The result is shown below.
Note1:- if you are using windows os you can opt for Zenmap, its GUI based and easy to install.
Note2:- I have not covered OS detection and trace route scan and version scan and script as the result will be shown in Aggression scan