ip-filter-tool-for-access-control-2025

Project Name: ip_filter_tool.py

A Python-based script that enforces network access control by maintaining an allow-list of authorized IP addresses. Built as part of the Google Cybersecurity Certificate portfolio to demonstrate applied scripting in real-world data security scenarios.

This security tool automates the process of updating an IP address allow-list to ensure only authorized employees have network access to sensitive patient records. It minimizes human error by programmatically removing known unauthorized IP addresses while preserving legitimate ones.

• Safe file operations using with open() (ensures automatic file closure)
• Defensive programming via least privilege access (read/write separation)
• String parsing and list transformations (.read(), .split(), .join())
• Conditional filtering and controlled list mutation (for + if + .remove())
• Basic data sanitation (manual detection of malformed/duplicate entries—optional future upgrade)

1. Reads a plaintext file named allow_list.txt containing IP addresses separated by spaces.
2. Splits the string into a Python list of IPs.
3. Iterates through the list and removes any IPs found in a predefined remove_list.
4. Rewrites the sanitized list back into the original file.

1. Clone Repository

bash

git clone https://github.com/codebyangelo/ip-filter-tool.git cd ip-filter-tool

2. Prepare your allow_list.txt file

192.168.97.225 192.168.1.10 192.168.158.170 10.0.0.25 999.999.999.999 192.168.201.40 192.168.58.57 172.16.0.5 192.168.0.100

3. Run the Script

Make sure you have Python 3.x installed, then:

bash

python ip_filter_tool.py

• Duplicate IP entries in remove_list require the script to run more than once to fully sanitize. This is a known limitation and can be enhanced using list comprehension or auxiliary filtering logic in future iterations.
• Malformed IPs (e.g., 999.999.999.999) are not filtered unless explicitly added to the remove_list. Format validation is intentionally omitted for this first build to maintain clarity and scope control.

• Implement duplicate-safe filtering using list comprehension or filter()
• Add optional IP format validation using regex or built-in ipaddress module
• Modularize logging for audit trails
• Expand to CSV or config-file support for enterprise-scale lists

This project was developed as part of the Google Cybersecurity Certificate. It reflects hands-on understanding of basic scripting, secure automation practices, and file-level access control. Demonstrating readiness for real-world infosec tasks.

Author: Angelo Ayton