Linux nmap Guide

Linux nmap Guide

Complete beginner-friendly guide to nmap on Linux, covering Arch Linux, CachyOS, and other distributions including network scanning, port scanning, and security auditing.

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Table of Contents

1. nmap Installation
2. nmap Basics
3. Port Scanning
4. Network Scanning
5. Advanced Scanning
6. Troubleshooting

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nmap Installation

Install nmap

Arch/CachyOS:

# Install nmap
sudo pacman -S nmap

Debian/Ubuntu:

sudo apt install nmap

Fedora:

sudo dnf install nmap

Verify Installation

Check nmap:

# Check version
nmap --version

# Check help
nmap --help

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nmap Basics

Basic Scan

Scan host:

# Scan single host
nmap 192.168.1.1

# Scan hostname
nmap example.com

Scan Network

Scan range:

# Scan IP range
nmap 192.168.1.1-254

# Scan subnet
nmap 192.168.1.0/24

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Port Scanning

Common Ports

Scan common ports:

# Scan common ports
nmap -F 192.168.1.1

# Fast scan
nmap --top-ports 100 192.168.1.1

All Ports

Scan all ports:

# Scan all ports
nmap -p- 192.168.1.1

# Or
nmap -p 1-65535 192.168.1.1

Specific Ports

Scan specific:

# Scan specific ports
nmap -p 22,80,443 192.168.1.1

# Scan port range
nmap -p 20-100 192.168.1.1

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Network Scanning

Service Detection

Detect services:

# Detect services
nmap -sV 192.168.1.1

# Version detection
nmap -sV -p 22,80 192.168.1.1

OS Detection

Detect OS:

# OS detection
nmap -O 192.168.1.1

# Requires root
sudo nmap -O 192.168.1.1

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Advanced Scanning

Stealth Scan

Stealth scanning:

# SYN scan (stealth)
sudo nmap -sS 192.168.1.1

# TCP scan
sudo nmap -sT 192.168.1.1

Aggressive Scan

Comprehensive scan:

# Aggressive scan
sudo nmap -A 192.168.1.1

# Includes OS, version, scripts

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Troubleshooting

Permission Errors

Use sudo:

# Some scans require root
sudo nmap -sS 192.168.1.1

# Or use TCP scan
nmap -sT 192.168.1.1

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Summary

This guide covered nmap installation, network scanning, and port scanning for Arch Linux, CachyOS, and other distributions.

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Next Steps

• Network Utilities - Network tools
• SSH Configuration - SSH setup
• Security Configuration - Security
• nmap: https://nmap.org/

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This guide covers Arch Linux, CachyOS, and other Linux distributions. For distribution-specific details, refer to your distribution's documentation.