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Two-Factor Authentication With Google Authenticator And LDAP

Introduction Earlier this year Google released their time-based one-time password (TOTP) solution named Google Authenticator. A TOTP is a single-use code with a finite lifetime that can be calculated by two parties (client and server) using ... Read more
Average Rating: 4.4
5 Reviews

v11.1–Add Signatures or Checksums to iRules via an iApp

iApps, introduced in v11, have a primary function in controlling the object creation and management for an application delivered by BIG-IP. As discussed previously, however, anything that can be accomplished in TMSH can be done in an iApp, so wha... Read more
1 Review

v11.1–External File Access from iRules via iFiles

New in BIG-IP version 11.1 are iFiles, a feature that allows users to load files through tmsh or the GUI onto the BIG-IP which can be referenced from iRules. This has an immediate use case of supplanting several of our codeshare entries for sorr... Read more
Average Rating: 4.9
8 Reviews

Base32 Encoding and Decoding With iRules

Introduction Anyone that's done any amount of programming has probably encountered Base64 encoded data. Data that is encoded with Base64 has the advantage of being composed of 64 ASCII characters, which makes it portable and readable with... Read more
0 Reviews

Implementing The Exponential Backoff Algorithm To Thwart Dictionary Attacks

Introduction Recently there was a forum post regarding using the exponential backoff algorithm to prevent or at the very least slow down dictionary attacks. A dictionary attack is when a perpetrator attacks a weak system or application by cyclin... Read more
0 Reviews

DNS Resolution via iRules: NAME::lookup vs RESOLV::lookup

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... Read more
Average Rating: 4.9
3 Reviews

APM Session Invalidation Using ASM

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 combine... Read more
Average Rating: 4.9
3 Reviews

v11: RDP Access via BIG-IP APM–Part 3

In Part 1, I configured a full Webtop in APM with a static RDP host. In Part 2 ,I modified that configuration to allow users to specify their RDP destination. In this article, I’ll make a couple changes to the final configuration in Part 2 to hav... Read more
Average Rating: 4.9
5 Reviews

Create a User Lockout Policy with Access Policy Manager

This article will cover a simple access policy that when completed will lock out a user using BIG-IP Access Policy Manager.  Start by making an access policy with the Device Wizard. Since I just want to make a quick and easy example, I’ll b... Read more
0 Reviews

Preventing Brute Force Password Guessing Attacks with APM–Part 4

F5er and DevCentral community member ystephie is back with another great solution (check out her first solution here: BIG-IP APM Customized Logon Page), this time tackling brute force attacks utilizing customizations with the BIG-IP Access Polic... Read more
2 Reviews

Preventing Brute Force Password Guessing Attacks with APM–Part 3

F5er and DevCentral community member ystephie is back with another great solution (check out her first solution here: BIG-IP APM Customized Logon Page), this time tackling brute force attacks utilizing customizations with the BIG-IP Access Polic... Read more
1 Review

Cookie Persistence and Troubleshooting

The BIG-IP persistence cookie is a valuable configuration option that allows stateful applications to remain persistent to a specific node with no additional configurations within the application or on the server(s) by doing something lik... Read more
2 Reviews

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... Read more
0 Reviews

iRules Concepts: Considering Context part 1

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 o... Read more
0 Reviews

BIG-IP APM–Customized Logon Page

Note: This solution is only applicable to version 10.x, version 11 doesn't use advCustHelp. The default logon page for the Access Policy Manager module is pretty basic, particularly so if only the minimal username and password ... Read more
Average Rating: 4.4
11 Reviews

iRules 101–#18–Revisiting the TCL Scan Command

I covered the Tcl scan command back in the iRules 101 – #16 – Parsing Strings with the TCL Scan Command, but this example (by Hoolio, who else?) was too good not to share with the community. The request involved parsing a log entry as efficientl... Read more
1 Review

Web Application Login Integration with APM

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 application... Read more
1 Review

Link Tracking With iRules - Part 3 - URI Filtering

This is the third article in a series on building link tracking functionality with iRules.  The previous articles were Link Tracking With iRules - Part 1 Link Tracking With iRules - Part 2 - Filtering Results In the first article, ... Read more
0 Reviews

Multiple Certs, One VIP: TLS Server Name Indication via iRules

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... Read more
0 Reviews

iRules IP Comparison Considerations with IP::addr Command

Anyone utilizing IP network comparisons in iRules is probably familiar with this syntax: 1: if { [IP::addr [IP::client_addr]/24 equals 10.10.20.0] } { 2: ##Do this 3: } In fact, there are several methods for doing a... Read more
Average Rating: 4.9
3 Reviews

iRules Data Group Formatting Rules

BIG-IP LTM supports internal and external classes (called Data Groups in the GUI) of address, string, and integer types.  An internal class is stored in the bigip.conf file, whereas external classes are split between the bigip.conf and the... Read more
Average Rating: 4.5
6 Reviews

Accessing TCP Options from iRules

I’ve written several articles on the TCP profile (click here) and enjoy digging into TCP.  It’s a beast, and I am constantly re-learning the inner workings.  Still etched in my visual memory map, however, is the TCP header format, show... Read more
Average Rating: 4.9
5 Reviews

Link Tracking With iRules - Part 2 - Filtering Results

A common request from application developers is the ability to track the popularity of different areas of their applications.  This could be which app is most popular or which image is linked to most often.  Analytics packages such a... Read more
0 Reviews

Help Kill IE6 with iRules

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 man... Read more
0 Reviews

Link Tracking With iRules - Part 1

One common request that application developers ask of their network admins is to report on the amount of times links in their applications are requested.  Various analytics packages including page trackers can be added to the applicatio... Read more
0 Reviews