🤖 AI Prompts Cheatsheet
Daniel Osei — AI-Assisted Security Engineer
What is Nmap?
Nmap (Network Mapper) is a powerful open-source tool for network discovery and security auditing. It is used by security analysts and penetration testers to discover hosts and services on a computer network, thus creating a ‘map’ of the network.
Installation
Nmap can be installed on various operating systems. Below are the instructions for some common platforms:
- Linux (Debian/Ubuntu):
sudo apt install nmap - Linux (CentOS/Fedora):
sudo yum install nmap - Windows: Download and run the installer from the official Nmap website.
- macOS: Use Homebrew:
brew install nmap
Basic Syntax
The basic syntax for running Nmap is:
nmap [options] [targets]
Discovery
Use Nmap for discovering hosts and services:
Ping Scan
To quickly discover active hosts:
nmap -sn 192.168.1.0/24
Service Version Detection
Detect service versions running on open ports:
nmap -sV 192.168.1.1
Scanning
Options for in-depth scanning:
TCP Connect Scan
Use TCP connect to identify listening services:
nmap -sT 192.168.1.1
Stealth SYN Scan
A quicker and less detectable option:
nmap -sS 192.168.1.1
Exploitation
Exploitation phase tips:
OS Detection
To identify the operating system being used:
nmap -O 192.168.1.1
Analysis
Post-scanning analysis:
Verbose Output
To get detailed output:
nmap -v 192.168.1.1
Output to File
Save results for later analysis:
nmap -oN results.txt 192.168.1.0/24
Evasion
Techniques to avoid detection:
Fragment Packets
To fragment packets for stealth:
nmap -f 192.168.1.1
Reporting
Generate reports from scans:
XML Output
For easy integration with other tools:
nmap -oX results.xml 192.168.1.1
Quick Reference Table
| Flag | Description |
|---|---|
| -sn | Ping scan (disables port scan) |
| -sS | SYN scan (stealth) |
| -sV | Service/version detection |
| -O | Operating system detection |
| -oN | Output normal format |
| -oX | Output XML format |
| -f | Fragment packets |
Pro Tips
- Combine flags for comprehensive scans. Example:
nmap -sS -sV -O 192.168.1.1for a stealth scan with version and OS detection. - Use –top-ports followed by a number to limit scans to most common ports.
- Leverage scripts using the -sC flag for security checks:
nmap -sC 192.168.1.1.
Real-World Examples
Example 1: Full Scan with OSD and Service Detection
nmap -sS -sV -O 192.168.1.0/24
Example 2: Stealth Scan with Output to File
nmap -sS -oN scan_results.txt 10.0.0.1