iRules, iRulesLX and Local Traffic Policies

iRules are still the most powerful tool on the platform – and the easiest place to create technical debt. We write, review and modernise the traffic logic in your estate with the same discipline as application code.

Choosing the right tool

• Local traffic policies for the routing, header and redirect logic that does not need code – faster, safer and expressible in AS3.
• iRules (Tcl) for everything policies cannot express: sideband calls, protocol manipulation, custom persistence, security helpers, high-speed logging and iStats.
• iRulesLX (Node.js) where the logic needs libraries, databases or external APIs.
• Retirement – removing iRules whose function the platform now provides natively, or that will not survive a move to BIG-IP 21.x or Distributed Cloud.

How we work

• Every iRule versioned in your repository and deployed through AS3 or your pipeline, with a test harness that exercises it before it reaches production.
• Performance profiling with timing statistics, so a convenience iRule does not become the busiest process on the device.
• Code reviews of existing iRules for security issues, deprecated commands and behaviour that changes between TMOS releases.

Recent projects

API routing and version steering, JWT inspection ahead of application servers, sideband integration with fraud and risk services, streaming rewrites for legacy content, and structured high-speed logging into SIEM platforms.