Simple Python Port Scanner

I built this project to get comfortable with Python's socket library and to understand how network connections work under the hood. It started as a basic script and I've been refactoring it to make it faster and more efficient.

What it does

• Scans a range of TCP ports on a target IP address.
• Uses multithreading (ThreadPoolExecutor) to scan ports in parallel (much faster than a basic loop).
• Identifies your own public IP for testing purposes.

How to run it

1. Clone the repo: git clone https://github.com/devogabs/python-port-scanner.git cd python-port-scanner

2. Install dependencies: pip install -r requirements.txt

3. Run the scanner: python src/scanner.py

What I learned building this

• Sockets: I learned how the TCP three-way handshake works and how connect_ex returns error codes instead of crashing the program.
• Concurrency: My first version was very slow. I learned how to use ThreadPoolExecutor to handle hundreds of port checks at the same time.
• Lambda Functions: I used lambdas to pass arguments into my threaded functions—which was confusing at first, but makes the code a lot cleaner.

Next Steps / Roadmap

• Add a SYN scan (stealth scan) using Scapy.
• Add the ability to export results to a .csv file.
• Implement a GUI or a more robust CLI with argparse.

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Disclaimer: This tool is for educational purposes only. Do not use it to scan networks you do not own or have explicit permission to test.