🔍 Python Port Scanner

A lightweight, multithreaded port scanner built in Python — inspired by Nmap. Built as part of a cybersecurity learning portfolio.

Features

• ⚡ Multithreaded TCP Connect Scan (100 threads by default)
• 🏷️ Service & Banner Detection
• 🖥️ OS Fingerprinting via ICMP TTL
• 📁 Export results to JSON or CSV

Usage

# Scan common ports
python port_scanner.py scanme.nmap.org

# Scan port range
python port_scanner.py 192.168.1.1 -p 1-1024

# Export to JSON
python port_scanner.py scanme.nmap.org --export json

Options

Flag	Description	Default
-p	Port range (1-1024, 80,443, common)	common
-t	Timeout per port (seconds)	1.0
--threads	Number of parallel threads	100
--export	Export format: json or csv	None
--output	Output filename	scan_results.*

How It Works

1. TCP Connect Scan — performs a full 3-way handshake to check if a port is open
2. Banner Grabbing — reads the service's greeting message to identify version
3. OS Fingerprinting — analyses ICMP TTL value to guess the operating system
4. Threading — uses Python's ThreadPoolExecutor to scan ports in parallel

⚠️ Legal Disclaimer

Only scan systems you own or have explicit permission to scan. Unauthorized port scanning may be illegal in your jurisdiction.

Tech Stack

• Python 3.x
• socket — TCP connections and raw ICMP
• concurrent.futures — multithreading
• argparse — CLI interface
• json / csv — result export