Cheatsheets

Comprehensive Security Tool Cheatsheet for Nmap

by n8n admin

🤖 AI Prompts Cheatsheet

Priya Nair — Prompt Engineering Expert

What is Nmap?

Nmap (Network Mapper) is a powerful open-source tool designed for network discovery and security auditing. It allows security professionals to discover hosts and services on a computer network, thus creating a ‘map’ of the network. Nmap is widely used for tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime.

Installation

Nmap can be easily installed on various operating systems. Here’s how:

  • Windows: Download the installer from the Nmap website and follow the prompts.
  • Linux: Use your package manager. For example, sudo apt install nmap for Debian-based systems or sudo dnf install nmap for Fedora.
  • MacOS: Use Homebrew with brew install nmap.

Basic Syntax

nmap [options] {target}

Example: nmap -sS 192.168.1.1

Network Discovery

Ping Scan

Check which hosts are up.

nmap -sn 192.168.1.0/24

OS Detection

Identify the operating system of remote devices.

nmap -O 192.168.1.1

Scanning

Service Version Detection

Determine service versions running on open ports.

nmap -sV 192.168.1.1

TCP Scan

Perform a full TCP connect scan.

nmap -sT 192.168.1.1

Exploitation

Script Scan

Run Nmap scripts for more detailed scan results.

nmap -sC 192.168.1.1

Analysis

Output Formats

Save results in different formats for analysis (XML, grepable, etc.).

nmap -oX output.xml 192.168.1.1

Evasion

Decoy Scan

Use decoy scans to obscure source IP.

nmap -D RND:6 192.168.1.1

Reporting

Human-Readable Output

Create easy-to-read scan reports.

nmap -oN report.txt 192.168.1.1

Quick Reference Table

Flag Description
-sS SYN scan (stealth scan)
-sT Connect scan
-O OS detection
-p Scan specific ports
-oN Normal output
-oX XML output

Pro Tips

  • Use the -Pn flag to skip host discovery if you know the host is up.
  • Combine multiple options like nmap -sV -O -p 1-65535 192.168.1.1 for comprehensive scans.
  • Use the --script option to specify custom scripts for specific types of vulnerabilities.

Real-World Examples

Performing a Targeted Scan

nmap -sS -sV -O -p 80,443 192.168.1.1

Scanning a Subnet

nmap -sP 192.168.1.0/24

Running a Stealth Scan

Run a stealth scan without being easily detected:

nmap -sS -D RND:6 192.168.1.1

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