Nmap

🔍 Nmap – Network Mapper Tool

Nmap (Network Mapper) is a free and open-source tool used for network discovery, security auditing, and port scanning. It’s a favorite among ethical hackers, system admins, and cybersecurity professionals.

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⚡ What is Nmap?

Nmap is a command-line tool used to discover hosts and services on a computer network by sending packets and analyzing the responses.

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🛠️ Common Uses

Use Case Description

Port Scanning Discover open/closed ports on a host

Network Discovery Find devices connected to a network

OS Detection Determine the operating system running on a target

Service Version Detection Identify software and version running on services

Vulnerability Scanning Identify known vulnerabilities via NSE scripts

Firewall Evasion Test firewall rules and bypassing techniques

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📦 How to Install Nmap

🐧 Linux:

sudo apt install nmap

🪟 Windows:

Download from: https://nmap.org/download.html

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💻 Basic Commands

Command Description

nmap <target> Basic scan of the target IP/hostname

nmap -p 1-65535 <target> Scan all ports

nmap -sV <target> Service version detection

nmap -O <target> OS detection

nmap -A <target> Aggressive scan (OS, services, traceroute)

nmap -Pn <target> Scan without ping (useful if ICMP is blocked)

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🧩 Example

nmap -A 192.168.1.1

Scans the device at 192.168.1.1 for services, OS details, and traceroute.

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📜 Nmap Scripting Engine (NSE)

Nmap comes with powerful scripts for:

• Vulnerability detection

• Malware scanning

• Brute force attacks

• Default credentials testing

• Web service detection

nmap --script vuln <target>

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🧠 Real-Life Applications

• 🔐 Penetration Testing – to find open ports and exploitable services

• 🖥️ Network Inventory – map all devices on a LAN

• 🚪 Firewall Testing – verify if ports are filtered or exposed

• 👮 Security Auditing – assess network exposure

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🧑‍🏫 Teaching Nmap – What You Can Cover

1. What is Nmap and why it's used

2. Installation on Windows & Linux

3. Basic command-line usage

4. Hands-on: Scanning local network IPs

5. Explanation of port states (open, closed, filtered)

6. Real-world ethical hacking scenario

7. Introduction to NSE scripting

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📚 Learning Resources

• 🔗 Official Site & Docs

• YouTube: Nmap tutorials for beginners

• Book: Nmap Network Scanning by Gordon Lyon (Nmap’s creator)