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. Fortunately, though, there is a mechanism by which I can distribute said geeky goodness for your avid assimilation. I give to you, the DC Top 5:


iRuling the New FSE Crop


Easily my favorite thing that happened this week was something I was fortunate enough to get to be a part of. A new crop of FSEs came through corporate this week to undergo a training boot camp that has been, from all accounts, a smashing success. A small part of this extensive readiness regimen was an iRules challenge issued unto the newly empowered engineers by yours truly. Through this means they were intended to learn about iRules, DevCentral, and the many resources available to them for researching and investigating any requirements and questions they may have. The results are in as of today and I have to say I’m duly impressed. I’ll post the results next week but, for now, here’s a taste of the challenge that was issued. Keep in mind these people range from a few weeks to maybe a couple months tops experience with F5, let alone iRules or coding in general, so this was a tall order. The gauntlet was laid down and the engineers answered, and answered with vigor. Stay tuned for more to come.

Mitigate Java Vulnerabilities with iRules


Jason put out a fantastic blog post this week showing how to thwart would be JavaScript abusing villains by way of iRules fu. Naturally I was interested so I investigated further. It turns out there was a vuln that cropped up plenty last week dealing with a specific string (2.2250738585072012e-308) that has a nasty habit of making the Java runtime compiler go into an infinite loop and, eventually, pack up its toys and go home. This is, as Jason accurately portrayed, “Not good.”. Luckily though iRules is able to leap to the rescue once more, as is its nature. By digging through the HTTP::request variable, Jason was able to quickly and easily strip out any possibly harmful instances of this string in the request headers. For more details on the problem, the process and the solution, click the link and have a read.

F5 Friday: ‘IPv4 and IPv6 Can Coexist’ or ‘How to eat your cake and have it too’


Whether it was the promise of eating cake or the timely topic of IPv4 trying to cling to its last moments of glory in a world hurtling quickly towards an IPv6 existence I don’t know, but this one drew me in. Lori puts together an interesting discussion, as is often the case, in her foray into the “how can these two IP formats coexist” arena. With the reality of IPGeddon acting as the stick, the carrot of switching to an IPv6 compatible lifestyle seems mighty tasty for most businesses that want to continue being operational once the new order sets in. Time is quickly running out, as are the available IPv4 addresses, so the hour is nigh for decisions to be made. This is a look at one way in which you can exist in the brave new world of 128-bit addressing without having to reconfigure every system in your architecture. It’s interesting, timely, and might just save you 128-bits worth of headaches.

Deduplication and Compression – Exactly the same, but different


There’s something that got passed over last week because of an absolute overabundance of goodness that I wanted to bring up this week, as I felt it warranted some further review and discussion. That is, Don’s look at Deduplication and Compression. Taking the angle of the technologies being effectively the same is an interesting one to me. Certainly they aren’t the same thing, right? Clearly one prevents data from being transmitted while the other minimizes the transmission necessary. That’s different, right? Still though, as I was reading I couldn’t help but find myself nodding in agreeance as Don laid out the similarities. Honestly, they really do accomplish the same thing, that is minimizing what must pass through your network, even though they achieve it by different means. So which should you use when? How do they play together? Which is more effective for your environment? All excellent questions, and precisely why this post found its way into the Top5. Go have a look for yourself.

Client Cert Fingerprint Matching via iRules


Continuing in the fine tradition of the outright thieving of other peoples’ code to mold into fodder for my writing, this week I bring to you an awesome snippet from the land down under. Cameron Jenkins out of Australia was kind enough to share his iRule for Client Cert Fingerprint matching with the team. I immediately pounced on it as an opportunity to share another cool example of iRules doing what they do best: making stuff work. This iRule shows off an interesting way to compare cert fingerprints in an attempt to verify a cert’s identity without needing to store the entirety of the cert and key. It’s also useful for restricting access to a given list of certs. Very handy in some situations, and a wickedly simple iRule to achieve that level of functionality. Good on ya, Cameron, and thanks for sharing.

There you have it, another week, another 5 piece of hawesome from DevCentral. See you next time, and happy weekend.