Post of the Week - Parsing Classes In iRules

DevCentral user duckhead posted a question to the iRules Forum asking for a way to parse a data group and display the results to a web page.  Joe and Colin discuss a couple of ways to go about this and toss in a little insight into the battle between development and marketing as to why a class is a class is a class is a datagroup is a class… For more information, check out the “iRule to parse Data Group?” thread in the iRules Topic Group. ...

Webcast - Exchange Best Practices

F5’s April Spence , James Hendergart, and Helen Johnson lead this webcast covering best practices for deploying BIG-IP with Microsoft Exchange 2010. After 18 months in market, a few best practices have emerged, and we’re happy to share them with our DC users. Today we covered the “All in one iRule” described in the Microsoft Exchange 2010 Deployment Guide, auth config for the Exchange Autodiscover service, the importance of persistence, and APM “Access Policy Manager” - a product from F5 that can be purchased separately as part of “Edge Gateway” or licensed as...

Webcast - F5 Solution for Microsoft Exchange

F5’s April Spence, James Hendergart, and Helen Johnson lead this webcast covering the F5 Solution for Microsoft Exchange.  In this webcast we discuss Exchange architecture, decisions about software or hardware load balancing, BIG-IP configuration templates, global redundancy with GTM, Access with APM, and a slew of Exchange related resources. The slides for this presentation can be downloaded from: 20110614-F5SolutionForMicrosoftExchange.pptx Related Articles on DevCentral ...

DevCentral World IPv6 Day Live Podcast

.    To help celebrate IPv6 Day, some of the DevCentral gang hosted a special IPv6 Day Roundtable Podcast. Hosts: Colin Walker, Jason Rahm, Jeff Browning, and Joe Pruitt. ...

Post of the Week - Optimization by Separation

DevCentral user jucao asked a question about logging the client user agent but only for a specific incoming IP address.  This discussion turned into one about not just solving this problem, but some subtle optimization tricks you can perform within iRules if you understand the protocols well enough.  hoolio gave some advice about minimizing address comparisons by moving that logic out of the HTTP_REQUEST event and into the CLIENT_ACCEPTED event which only occurs once per connection.  We love our iRules Opimizations!!! For more information, check out the “wanna record user_agent...

Post of the Week - Code Injection

DevCentral user Jason was trying to figure out how to insert a POP-under ad from an ad company without disrupting the site itself.  Now, while we don’t officially endorse pop-up or under ads, it is definitely feasible do to in an iRule.  In this weeks post of the week, we talk about several ways of inserting content into response streams with iRules and include some issues that come with each approach. For more information, check out the “Code injection” thread in the iRules Topic Group. ...

Post of the Week - SNAT Source Ports

DevCentral user LillyM was working with SNAT’s in an iRule and was wondering what the options were to preserve the source port on the connection.  George gives the rundown on a solution with v10.x of BIG-IP and some pitfalls you’ll need to avoid in the configurations to make sure things work the way you expect. For more information, check out the “avoid changing source port of the connection while using SNAT” thread in the Advanced Design & Config Topic Group. ...

Post of the Week - I Can Haz Corndog

DevCentral user mtobkes was working on an iRule to help with HTTP Referral enforcement but was having an issue with coding logical comparisons.  We used this post as a springboard to talk about how logical operators work in TCL and tossed in a few optimization techniques on the side.  If you are wondering how corndogs fit into this post, you’ll just have to watch this weeks Post of the Week to find out! For more information, check out the “Error with or operator” thread in the iRules Topic Group. ...

Post of the Week - Encryption in iRules

Saving 100x cycles in an iRule via encryption choices? Yes, it's possible. This week in the PoTW user Chris Huston gets the low down on which encryption method is best for his particular use case from none other than hoolio and spark themselves. Now that's a power duo! For more information, check out the “iRule performs 100x slower under load” thread in the iRules Topic Group. Related Links on DevCentral ...

Post of the Week - Classes

Colin and Joe pick up on an older forum post about access to classes (Data Groups) that was updated this week with some impressive performance findings introduced in BIG-IP version 10.2.1.  We go over a little bit of the history of classes and the associated iRule commands (findclass, matchclass, and class) for accessing them. For more information, check out the “matchclass versus class in v10 for address comparisons” thread in the iRules Topic Group. Related Links on DevCentral ...

Post of the Week - Serving Local Files

User F5nubster brought up the question in the iRules forum around the topic of retrieving log files from the BIG-IP  without a SCP file copy.  Joe and Colin discuss several methods for retrieving file system content as well as alternate ways to send your log content off the device with the various logging options.  Can you think of any other options for user F5nubster?  If so, post them to the comments. For more information, check out the “Is it possible to serve local files via HTTP” thread in the iRules...

Post of the Week - Regular Expressions

In their second week back in the saddle, Joe and Colin talk about regular expressions and why they are “pure evil incarnate”, according to Joe.  They talk about the pitfalls of regex oversaturation, other less costly alternatives, how to use them, which to prioritize and when it’s actually a good thing to use one of those “evil” regex things.  Thanks to user Joe Pippitone for the inspiring post. For more information, check out the “Regex” thread in the iRules Topic Group. ...

Post of the Week - Dynamic URL Forwarding

The Post of the Week (PotW) rides again! This week Joe and Colin dive into a question posed in the forums about how to do dynamically updated URL redirection. There are a few different options to tackle this, and they discuss the pros and cons of each approach ranging from old-school static variables to tables and even iControl.  Tune in every week as the team delves into hot and interesting forum topics in this much requested series. For more information, check out the “URL Forward with a POST change” thread...

Post of the Week–Application Credential Passing

I thought I’d take a look this week at this interesting forum thread.  User Carl Gottlieb posted requesting some guidance on preventing replay attacks in a scenario where users login into application 1 and the credentials for application 2 are passed in hidden fields (but in the clear) back to the client.  Enjoy!   Technorati Tags: F5 DevCentral,PotW,Post of the Week,iRules,Jason Rahm

Colin And Jeff Discuss Their Trip To Japan

Joe sat down with Jeff and Colin and took a few minutes to discuss their recent trip to visit our team in Tokyo, Japan.  Listen in and hear about a recap of the meetings they were involved with – including an awesome event with the DevCentral User Group.  You will also get a taste of what they dined on...

F5 Tech Field Day – Delegate Roundtable

Web Magazine Gestalt IT brings together innovative IT product vendors and independent thought leaders who have immense influence on the ways that products and companies are perceived and understood by the general public. F5 Networks hosted a session for the Tech Field Day on Thursday, July 15th.  In the final...

F5 Tech Field Day - Tales From The Woods With iControl and iRules

Web Magazine Gestalt IT brings together innovative IT product vendors and independent thought leaders who have immense influence on the ways that products and companies are perceived and understood by the general public. F5 Networks hosted a session for the Tech Field Day on Thursday, July 15th.  In this session,...

F5 Tech Field Day – Intro To F5 As A Strategic Point Of Control

Web Magazine Gestalt IT brings together innovative IT product vendors and independent thought leaders who have immense influence on the ways that products and companies are perceived and understood by the general public. F5 Networks hosted a session for the Tech Field Day on Thursday, July 15th.  In this session,...

Joe And Colin Discuss Interop At The F5 Whiteboard

At Interop, Joe and Colin give a rundown on things they were presenting and some interesting things that came from the customers while they were manning the F5 whiteboard.  Technorati Tags: F5,DevCentral,Interop,Geolocation,Sanitizing,GTM,iControl,iRules,Colin Walker,Joe Pruitt

Colin Walker Talks Geolocation With iRules At Interop

While we were down at Interop in Las Vegas last week, Colin and Joe had a chance to give a couple of short 5-minute presentations at the F5 booth.  We just happened to have the camera handy so we shot Colin discussing using Geolocation with iRules.  Most folks understand the need for making Geolocation based decisions for GTM/DNS based decisions, but Colin gives a few ideas on how to use it once the users have been directed to a specific datacenter. Technorati Tags: F5,DevCentral,Interop,Geolocation,iRules,Colin Walker

How Butler University Survived The College Playoffs With WebAccelerator

Butler University Systems Administrator Nate Partenheimer stopped by the F5 booth at Interop and gave us a run through on how WebAccelerator helped their school website survive the teams success in this year’s college basketball playoffs. Go Dogs! Technorati Tags: F5,DevCentral,Interop,WebAccelerator,iRules,Butler University,Nate Partenheimer,Joe Pruitt

Post of the Week – High Speed Logging, iRules and you

This week Jason suggested a pretty awesome post regarding High Speed Logging (HSL). I thought I'd take this as an opportunity to briefly talk about HSL in iRules since it's a pretty cool feature that didn't get a ton of press when it went live. I then, of course, went on to talk about the post in particular and some of the questions being asked, and share a bit of Spark's ever awesome insight into iRules fu. ...

Post of the Week – The triumphant return, thanks to LTM VE

The launch of the LTM VE forum and the amazing discussions happening there seemed like an appropriate time to reinstate the post of the week.  Each week we’ll pick a post to highlight, then discuss it, why it’s interesting, and any additions or extras we can throw in to add to the post.  This week I’m trying to provide answers to the top 10 questions asked already about the LTM VE. The questions are, in no particular order: ...

Interview with iRule Contest Finalist Henrik Gyllkrans

Jeff and Joe take some time after our presentation in Stockholm to talk with iRule Contest finalist Henrik Gyllkrans about writing fast iRules, his company Advanced IP, and his winning cookie tampering iRule.     Technorati Tags: F5,DevCentral,iRules,Stockholm,Henrik Gyllkrans,Joe Pruitt

DC Post of the Week - SSL Info in your HTTP Headers

In this week's Post of the Week take a quick look with Colin at how iRules can help handle your needs with SSL info in your HTTP headers, as well as a couple of things to keep in mind next time you want to implement this kind of iRule. For more information, check out the thread in the iRules forum.    Technorati Tags: F5, DevCentral, Post of the Week, DCTVPOTW, iRules, SSL VPN, HTTP, Colin Walker

Election Hash Load Balancing

F5 Solutions Architect Nathan McMahon explains Election Hash Load Balancing...

Universal Persistence with SSL Offload

F5 Field Systems Engineer Christopher Schaefer sits down with Colin & Deb to explore an interesting iRules solution:  Persistence for mobile devices running a proprietary stateful TCP application while roaming across cell towers mid-session.  In the absence of a consistent IP address or any identifying header information, Chris discovered the client mobile ID embedded in the binary data of the traffic stream, and built a custom Universal Persistence solution.  This solution was only possible because of the SSL offload capability of LTM, which allows LTM to decrypt the traffic before...

Active-Active Database Load Balancing

F5 Field Systems Engineer Patrick Chang explains an iRules solution that supports 2 active database instances in different data centers behind a web application.  The goal is to provide the optimal user experience by load balancing requests for both the web/application tier and the database tier to a local data center whenever possible.  Since cross-data center database replication takes approximately 20 seconds, one instance is preferred for database writes, and an iRule that reads and inserts time-stamped cookies reliably directs traffic to the closest database instance when possible, and to the...

DC Post of the Week - Switch Gone Wild

“Switch” Gone Wild This week Deb looks at a post from gregt, who was having some trouble with choosing a pool based on the requested URI. Posters aherrman and cmbhatt (CB) jump in to correct the logical order of comparisons (most specific first, please!).  CB further suggests using switch with wildcards to replace the nested “if” commands that used “starts_with” and “ends_with”. You’ll probably want to pull up the post to follow along on this one, so here it is:  iRule sends to wrong Pool and Port...

DC Post of the Week - Disposing Your Content

Disposing Your Content Properly This week Colin & Deb take a look at a post from gerardo.garcia in which he ask if there is a way to force a document download instead of having recognized content types displayed in the browser automatically. Hoolio & Colin offer a simple iRule solution involving the HTTP::header command and the Content-Disposition header. Here’s the post:  Content Disposition Technorati Tags: F5, DevCentral, Post of the Week, DCTVPOTW, HTTP, Content-Disposition

DevCentral EMEA Tour 2007, Episode 2

In this next installment of Colin's European tour, Sam Pickles is kind enough to take time out of his day between presenting, answering questions and generally assisting with the CoE in general to talk to us about an interesting experience he had in a bake-off. iRules helped seal the deal again, along with BIG-IP and TMoS and their astounding performance.

The requirement is 65K connections? Sure, we can do that. How about 200K instead? 'Nuff said.

DevCentral EMEA Tour 2007, Episode 1

In this video, which is the first in a series of 3 videos captured on Colin's recent trip to Europe, we talk with one of F5's partners, Nebulas Security, to discuss how they're making use of F5's technology in interesting ways. As it turns out, they've recently used F5's iRules technology in a system migration to avoid large amounts of extra work and/or disruption in the client experience.

iRules in the hands of a partner - pure power

Features: New iRule Editor makes it faster and easier to edit, backup even deploy iRules

Announcing the iRules Wiki, new from DevCentral!