Colin Walker

Version 11 of BIG-IP brought with it many enhancements and new features ranging across the entire product. iRules improvements and features were among the cooler things changed, in the opinion of this avid iRuler. Between sideband connections, iFiles and improvements of already existing functionality, it's hard to imagine there is more yet to discuss in v11 iRules goodness, but there is. iStats were introduced in v11, and are worth talking about, as they can dramatically change the way you are solving problems, depending on your deployment. In this 2-parter we'll talk about iStats first from a higher level overview/introduction perspective, and then a bit more in-depth in part 2, talking about specific metrics that are measurable, commands available from within iRules, etc. What are iStats? iStats are user-created custom statistics, accessible from both the data p... (more)

HTTP Request Cloning via iRules, Part 1

One of the requests that I've seen several times over the years is the ability to completely clone web requests across multiple servers. The idea is that you can take the HTTP traffic coming in bound for pool member A and distribute it, in its entirety, to pool member B. Or perhaps members B-G..whatever your needs are. This can be helpful for many reasons, security auditing, test or dev harnesses, archival, etc. Whatever the reasons, this has been a repeated question in the forums and in the field. While clone pool functionality works to some degree for this, it doesn't work quit... (more)

What Could You Do with Your Code in 20 Lines or Less?

What could you do with your code in 20 Lines or Less? That's the question I ask (almost) every week for the devcentral community, and every week I go looking to find cool new examples that show just how flexible and powerful iRules can be without getting in over your head. Here are a few more cool iRules from the forums. This week I’ve included one of the simplest, shortest iRules to ever make the 20LoL. It just struck me as something quite useful that I’m willing to bet several people will look at and say “oh, that’s handy” despite the fact that it’s not complex or long.  Keep... (more)

iRules Concepts: Considering Context part 2

In part 1 of this brief series we talked about what context means while coding, how it affects our perception of things and the different contexts within iRules that are inherent and would be covered in this 2 part-er. As a refresher, those contexts are: Clientside Serverside Modifiers & Special Cases Request based Connection based We've covered the first three, so that leaves us ready to discuss "Request based" & "Connection based" context. Unlike Clientside vs. Serverside context Request Based context doesn't have anything to do with which side of the proxy the actions are happ... (more)

E-Mail is Bigger Security Risk than Twitter

Summer vacations, travel and distractingly favorable weather may interrupt the normal work weeks for some, but they can't stop the content. DevCentral has been alive and well through these sunny days thanks to the blogs, docs and media cruising through from various contributors. With many irons in the fire, plans on the drawing board and other assorted clichés at work helping to drive the "Next Big Thing" for the DevCentral team, you can only expect to see things scale upward and onward in terms of content pacing. I'll try to help you keep up. To that end, here's this week's Top5... (more)