For the background and introduction to this series, click here. The TL;DR for Project Chain Links is to:
And with that, let's get on with it!
The background: A coworker is trying to create some basic access controls for a web application and finds a codeshare entry on DevCentral that looks like it will fit the need.
The problem: The codeshare entry is quite dated, and was tested for BIG-IP version 9.4. You run BIG-IP version 14.1, so you need to research the iRule presented in the codeshare entry:
Solution: Your solution should result in a functional iRule and any other helper objects that successfully blocks access to your web app if not sourced from any of five different IP address ranges.
Questions for understanding: