PortMapper

A Custom TCP Port Scanner for Network Reconnaissance

PortMapper is a lightweight Python-based TCP port scanner designed for network reconnaissance and security testing. It efficiently scans target hosts to identify open ports and potential entry points.

Features

• 🚀 Fast TCP port scanning
• 🎯 Configurable port range scanning
• ⏱️ Built-in timeout handling for closed ports
• 🛡️ Robust error handling (keyboard interrupts, DNS errors, connection errors)
• 📊 Clean and informative output
• 💻 Cross-platform compatibility

Prerequisites

• Python 3.6 or higher
• No external dependencies required (uses built-in libraries only)

Installation

git clone https://github.com/krinathakkar646/PortMapper.git
cd portmapper

Usage

Basic Usage

Edit the target variable in the script to specify your target host:

target = "scanme.nmap.org"  # Change this to your target

Then run:

python portmapper.py

Customizing Port Range

Modify the range in the script:

for port in range(1, 100):  # Scan ports 1-99

Change to:

for port in range(1, 1001):  # Scan ports 1-1000

Example Output

--------------------------------------------------
SCANNING TARGET : scanme.nmap.org
TIME STARTED : 2024-12-06 14:30:45.123456
--------------------------------------------------
Port 22 is Open 
Port 80 is Open 
Port 443 is Open 
--------------------------------------------------
[*] Scan Complete.

How It Works

1. Target Definition: Specifies the hostname or IP address to scan
2. Socket Creation: Creates TCP sockets for connection attempts
3. Port Scanning: Iterates through specified port range
4. Connection Testing: Attempts to connect to each port with a 1-second timeout
5. Result Reporting: Displays open ports in real-time

Code Structure

import sys
import socket
from datetime import datetime

# Define target
target = "scanme.nmap.org"

# Display banner with scan information
# Create socket connection for each port
# Test connectivity and report open ports
# Handle errors gracefully

Error Handling

The scanner includes comprehensive error handling for:

• Keyboard Interrupt (Ctrl+C): Gracefully exits the program
• DNS Resolution Errors: Handles invalid hostnames
• Connection Errors: Manages network connectivity issues

Legal Disclaimer

⚠️ IMPORTANT: This tool is intended for authorized security testing and educational purposes only.

• Always obtain explicit written permission before scanning any network or system
• Unauthorized port scanning may be illegal in your jurisdiction
• The author is not responsible for misuse of this tool
• Use responsibly and ethically

Only scan systems you own or have permission to test (e.g., scanme.nmap.org is provided by Nmap for testing purposes).

Common Use Cases

• Network security auditing
• Vulnerability assessment
• Network troubleshooting
• Educational purposes and learning
• Security research

Limitations

• Currently scans TCP ports only (no UDP support)
• Sequential scanning (not multithreaded)
• Basic port detection (no service identification)
• Manual target configuration required

Contributing

Contributions are welcome! To contribute:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/improvement)
3. Commit your changes (git commit -am 'Add new feature')
4. Push to the branch (git push origin feature/improvement)
5. Open a Pull Request

Roadmap

Potential future enhancements:

• Command-line argument support
• Multiple target scanning
• Service version detection
• JSON/CSV output formats
• Multithreading for faster scans
• UDP port scanning support
• Port range specification via CLI
• Save results to file

Version History

• v1.0 (December 2024) - Initial release with basic TCP port scanning

Troubleshooting

"Hostname could not be resolved"

• Check your internet connection
• Verify the target hostname is correct
• Try using an IP address instead

"Could not connect to server"

• Check your network connection
• Verify firewall settings
• Ensure target is accessible from your network

Slow scanning

• Reduce timeout value (currently 1 second)
• Reduce port range
• Check network latency

Author

Krina Thakkar

• GitHub: @krinathakkar646

Acknowledgments

• Thanks to the Python community for excellent documentation
• Inspired by Nmap and other network scanning tools
• Special thanks to scanme.nmap.org for providing a legal testing target

Support

If you encounter any issues or have questions:

• Open an issue on GitHub
• Check existing issues for solutions
• Review the troubleshooting section above

Disclaimer

This tool is provided "as is" without warranty of any kind. Use at your own risk. The author assumes no liability for any misuse or damage caused by this program.

---

⭐ If you find this project useful, please consider giving it a star on GitHub!