NMAP: A command-line tool for network scanning

 WHAT IS NMAP?

 Nmap is short for Network Mapper, is a free, open-source tool that helps with network security and discovery. It's used by IT professionals and security enthusiasts to scan networks, identify vulnerabilities, and perform penetration testing.

Nmap allows network admins to find which devices are running on their network, discover open ports and services, and detect vulnerabilities.

 WHY USE NMAP:

Nmap is used to identify devices connected to a network and to assess their security. It's used by network administrators, security testers, and others to: 

1. Discover devices: Find all the devices connected to a network 

2. Identify services: Find out what services are running on each device 

3. Detect vulnerabilities: Identify open ports and assess the security of target systems 

4. Map networks: Create a map of a network, including which devices are connected and what services they're running 

5. Detect operating systems: Find out what operating systems are running on each device.

COMMANDS THAT CAN  BE USED:

1. PING SCAN: >nmap -sp ip address/

 [scans the lists of devices that are running on a subnet].

2. SCAN A SINGLE HOST: >nmap scanme.nmap.org 

[scans a single host and are used by popular services like SQL, APACHE ETC]

3. SCANNING MULTIPLE HOST: >nmap ip addresses 

[write all the ip address at once to scan all of the hosts at the same time] 

4. SCANNING FROM A FILE: >nmap -iL /input_ips.txt

[If you want to scan a large list of IP addresses, you can do it by importing a file with the list of IP addresses.]

WHY NMAP IS USEFUL:

Nmap helps companies identify vulnerabilities in their security infrastructure.

Nmap helps companies develop more robust defense measures.

Nmap helps companies manage service upgrade schedules and monitor host or service uptime.

CONCLUSION:

As a pentester, using Nmap will help you scan and discover informations about your network, host, firewalls, operating system and lets you analyze in detail.