Project Chain Links Challenge 2: Modifying a Codeshare Example

For the background and introduction to this series, click here. The TL;DR for Project Chain Links is to:

  1. Present a clear problem to solve
  2. Make sure the problem is small enough to tackle quickly
  3. Provide a solution a few days later for validation

And with that, let's get on with it!

Challenge #2

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:

  • Will it work as is?
  • If it doesn't work, what are the minimal changes you will have to make?

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.

Bonus challenge:

  • Alter the solution to support 20 different IP address ranges, if necessary
  • Alter the solution again to support 100 different IP address ranges, if necessary
  • Alter the solution to only block access to the web app based on source IP if the URL begins https://www.nerdknobs.local/admin-portal/

Questions for understanding:

  • In what situations should you analyze and potentially refactor iRules?
  • How might you use the iRules documentation to inform your refactoring efforts?
  • How might you use performance testing to inform your refactoring efforts?

Published Jan 22, 2020
Version 1.0

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