Python nmap port scanner

Introduction

In this tutorial, you'll learn how to create a Python port scanner using both the socket method and the nmap method. This is a foundational skill for anyone interested in ethical hacking and network security. By the end of this guide, you will have practical scripts that you can use to scan ports and explore network vulnerabilities.

Step 1: Install Python

Before you begin coding, ensure you have Python installed on your system.

1. Go to the Python website.
2. Download the latest version of Python for your operating system.
3. Run the installer and follow the instructions to complete the installation.
4. Verify the installation by opening a terminal or command prompt and typing:

   python --version
   

Step 2: Download Required Scripts

You'll need the Python scripts for both the socket and nmap methods. Access the following links to download the code:

• Socket method (regex): port_scanner_regex.py
• Nmap method: nmap_port_scanner.py

For IP address methods, download these scripts:

• Socket method: port_scanner_ip_obj.py
• Nmap method: nmap_port_scanner_ip_obj.py

Step 3: Run the Python Socket Port Scanner

To test the socket method, follow these steps:

1. Open your terminal or command prompt.
2. Navigate to the directory where you downloaded the script.
3. Run the script using:

   python port_scanner_regex.py
   

4. Specify the target web server (e.g., example.com) and the port range you want to scan.

Practical Tip

Make sure to have permission to scan the target server to avoid potential legal issues.

Step 4: Test Against a Web Server

After running your script, test it against a known web server:

1. Use a common web server like www.google.com.
2. Specify a port range, such as 80 to 100.
3. Observe the output to see which ports are open.

Step 5: Implement Timeout for Connection Checks

To enhance your port scanner's efficiency:

1. Modify the script to include a timeout.
2. This can be done by adding a timeout parameter in your socket connection, like this:

   socket.setdefaulttimeout(2)
   

3. This will help avoid long waits for unresponsive ports.

Step 6: Test on Kali Linux

If you have access to Kali Linux, the process is similar:

1. Open the terminal.
2. Run the socket script:

   python port_scanner_regex.py
   

3. Follow the same testing procedures as before.

Step 7: Troubleshoot Nmap Issues

If you encounter issues while using the nmap script:

1. Ensure that nmap is installed on your system. You can install it using:

   sudo apt-get install nmap
   

2. Run the nmap script:

   python nmap_port_scanner.py
   

3. Verify your syntax and target specifications.

Step 8: Compare Socket and Nmap Scripts

Understand the differences between the two methods:

• Socket Method:

  • Directly connects to ports.
  • Simpler and lightweight.

• Nmap Method:

  • More comprehensive scanning capabilities.
  • Can provide service version detection and OS detection.

Conclusion

You've now learned how to create a Python port scanner using both socket and nmap methods. Remember to always have permission before scanning any network to stay within legal boundaries. For further exploration, consider delving deeper into ethical hacking techniques and expanding your knowledge of network security. Happy coding!