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Wielding the Power of the Network to Better Applications Everywhere

Colin Walker

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Latest Blogs from Colin Walker
Welcome to a special "yes I know it's Wednesday but I won't be here Friday" edition of the Top5. There has already been some great content in the last week or so, which makes it easy to do an edition mid-week, but that's not unusual. Given the amount of awesome content that can general...
F5 uses TCL as the interpreter for iRules. Many people often ask why that is. This questions is usually followed up by an immediate, "Why not Perl?" or "Why not Java" or "Why not <fill in my preferred language of choice>?". I understand the question, and frankly I'm a Perl guy fr...
We're putting the band back together. And by band, I mean team. And by "putting back together" I mean we're all going to be in the same place, physically. This is a rarity for our remotely distributed team, but next week it is happening, and that is a great thing. It means planning, po...
  Competitive advantage for network technologies will be determined by a vendor’s ability to allow its customers to create custom features through a programmable front end and then share these ideas with a broader community. The community will become a self feeding ecosystem that w...
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 existin...
What could you do with your code in 20 Lines or Less? That's the question I ask (sometimes?) 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. Thi...
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 mem...
What could you do with your code in 20 Lines or Less? That's the question I ask (sometimes?) 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. This ...
The holidays have passed, the new year is upon us and there is much geeky goodness to be thankful for. I am thankful for the forums and the wikis, the tech tips and blogs. I am thankful for the outstanding community that drives it all, and the supporting cast of hundreds within F5 that...
  What could you do with your code in 20 Lines or Less? That's the question I ask (sometimes?) 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. This...
Within iRules, in addition to mastering the language syntax and tricks therein, there is an added layer of understanding that can help in taking your iRules fu to a whole new level. Connection State. Connection states are relatively simple in concept, but aren't referenced very often ...
The iRules CodeShare on DevCentral is an amazingly powerful, diverse collection of iRules that perform a myriad of tasks ranging from credit card scrubbing to form based authentication to, as in today's example, limiting the number of HTTP sessions allowed. While the codeshare is outst...
What could you do with your code in 20 Lines or Less? That's the question I ask (sometimes?) 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. This we...
There are so many things that you can do with iRules that it can be pretty staggering to narrow down what the "most useful" commands are, but if I were given that task and absolutely had to, I would say that DNS resolution ranks up there pretty high on the most powerful list. Perhaps n...
Introduction: Whenever customers expose their internal resources on the Web using VPNs or SSL VPNS there is still some concern over what type of traffic comes through the connection. In order to assist with these concerns we can provide a combined SSLVPN solution with added Applicatio...
With the release of BIG-IP version 11 there are many, many new features and capabilities to come up to sped on. Not the least of which are the additions and changes to the already powerful iRules infrastructure. iRules, as a whole, is an amazingly powerful, flexible technology. We've s...
10,000 is a relatively momentous number for many reasons. It's a nice, round number like 10, 100, 500, and so on. It's a stepping stone into the five digit numeric space, and it's quite an accomplishment depending on what it is you're counting. A few fun facts about 10,000: It is t...
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 ...
Language is a funny thing. It's so easily misunderstood, despite the many rules in place to govern its use. This is in part, of course, due to dialects and slang, but context shouldn't be underestimated as an important piece of understanding linguistics. A perfect example of context c...
As rare as the Hippocampus and as fleeting as the Pegasus, this special Monday edition of the Top5 is brought to you by "too much to get done on Friday"(tm). Think of it as a bonus edition though, not delayed, as this Top5 comes bearing wondrous gifts from around DevCentral. From iRule...
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. By a show ...
In a shocking turn of events, the gracious sales readiness team invited me back to yet again present an iRules Challenge to the inbound FSEs during their multi-week grooming process here at F5 Seattle, lovingly known as "boot camp". It's a joy for me to be a part of these boot camps no...
The 20 Lines or Less, the DC weekly podcast, 99% of the hundreds of blogs Don and Lori seem to put out each week...these are but a few of the things you won't see this week in the DC Top 5. With as good as the content is that's getting left out, you can only imagine how good the stuff ...
It would seem that, at least in this contest, everyone can indeed be a winner. I got the distinct pleasure to, once again, help contribute to the iRules delinquency education of our inbound FSE crew while they were here in Seattle for their boot camp. These folks are all technical, but...
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. This week I...
The Sales Readiness team is back at it, training another awesome crop of FSE type peoples here at F5 headquarters. And for the third time in a row, I get the esteemed honor/fun of building an iRules challenge to push them into learning iRules, the tools it takes to build them, how to r...
When talking about IT performance and rating "must haves", data center reliability is often right near the top of the list, and for good reason. Performance and scalability, features and  functionality don't matter much unless the application is up and available. We here at F5 tend to ...
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. This week w...
As we hurtle forward through the information age we continue to find ourselves increasingly dependant on the applications upon which we rely. Whether it's your favorite iPhone app or the tools that allow you to do your job, the applications that you interact with and the information c...
  Hot off the presses from the AskF5 team, I bring to you the announcement many of us have been waiting for...iHealth for the masses! If you don't know what iHealth is yet, get out from under your rock and check it out. It's an amazing analysis, investigation and error prevention tool...
An age old question that we’ve seen time and time again in the iRules forums here on DevCentral is “How can I use iRules to manage multiple SSL certs on one VIP"?”. The answer has always historically been “I’m sorry, you can’t.”. The reasoning is sound. One VIP, one cert, that’s how it...
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. Digging thr...
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. Continuing ...
For those that haven’t gotten the memo yet, IE6 is on its way out. I know this has been something developers, myself included, have been hoping for for quite some time now. IE6 is old and frankly doesn’t offer the support needed by far too many web applications these days. None of thi...
It’s FSE iRules Challenge time again, folks, so strap on your geek-hats and follow along. First, before I get too deep into what the challenge actually was this time around, I want to steal a word or two from the last challenge’s announcement to describe what an FSE is. FSEs are the ...
The concept of a friendly URL is a pretty simple one. Basically you want to make things in your application, on your website, etc. easier to access. This stems from the fact that most applications these days make use of increasingly complex paths for a multitude of reasons. Whether it’...
While the groundhog may have promised an early spring, we’re still feeling the chill here in Seattle. Naturally though that hasn’t impeded the content marching its way across DevCentral in the past weeks. We’ve had everything from awesome blogs and Tech Tips to user contributed content...
Last week I wrote about the iRules challenge issued to the FSEs again, and showed my intended solution.  Go take a look at that post for a point of reference if you like, or just dive in. Today I want to give props where props are due, and show off the winner and two runners up of the ...
Last week I wrote about challenging the new FSEs that were here attending boot camp.  I got to throw together some requirements for the engineers to cut their teeth on, so to speak, and learn about iRules and at least as importantly how to make use of the resources they have avail...
If your week has been anything like mine, then you’ve had plenty to keep you busy. While I’d like to think that your “busy” equates to as much time on DevCentral checking out the cool happenings while people get their geek on as mine does, I understand that’s less than likely. Fortunat...