Nmap, also known as Network Mapper, is a highly effective and adaptable network scanning tool. Its primary purpose is to explore networks and perform security audits. With Nmap, users can effortlessly discover hosts and services on a computer network, detect operating systems, identify open ports, and collect information about different network devices.
NMAP is used for:
Network Discovery: Nmap can scan an entire network or a range of IP addresses to identify active hosts available on the network.
Ex: nmap -sn 192.168.0.0/24
This command performs a ping scan (-sn) on the specified IP range (192.168.0.0/24) to discover live hosts on the network without performing any port scanning.
Port Scanning: Nmap can scan target hosts to determine which ports are open, closed, or filtered. This information is valuable for assessing the security posture of a network and identifying potential vulnerabilities.
Ex: nmap -p 1-100 192.168.1.100
This command scans ports 1 to 100 on the target IP address 192.168.1.100 to check which ports are open and potentially accessible.
Service Version Detection: Nmap can probe open ports to determine the version and type of services running on those ports. This helps in identifying specific software versions and potential vulnerabilities associated with them.
Ex: nmap -sV 192.168.1.100
This command performs a service version scan (-sV) on the target IP address 192.168.1.100, which attempts to determine the version and type of services running on open ports.
Operating System Detection: Nmap can analyze network responses to identify the operating systems running on remote hosts. This information is helpful for network administrators to understand the composition of their network and implement appropriate security measures.
Ex: nmap -O 192.168.1.100
This command performs an OS detection scan (-O) on the target IP address 192.168.1.100, which tries to identify the operating system running on the target system based on various network fingerprints.
Scripting and Automation: Nmap provides a scripting engine (NSE - Nmap Scripting Engine) that allows users to write custom scripts to automate various network scanning tasks and perform specialized security checks.
Ex: nmap -p 80 --script=http-title 192.168.1.100
This command scans port 80 on the target IP address 192.168.1.100 and uses the http-title script to extract and display the title of the web page served by the web server on port 80. Scripting in nmap allows you to perform custom tasks and automate scanning processes.