I find it interesting when customers try to use our products in ways that we never considered.  For instance we had a customer that was suffering from frequent denial of service attacks and wanted to look at whether BIG-IP WebAccelerator would help.  My first thought was why an accelerator you need a security product.   After listening as the customer explained that the DoS attacks had progressively gotten more advanced and there was now no way to differentiate legitimate traffic from DoS traffic. 

During the attacks the database was getting overwhelmed causing the entire site to become unusable.  For some reason all requests whether for an image, page or JavaScript resulted in a call to the database.  The plan was two-fold use WebAccelerator to offload all static content and provide further offload of the database through dynamic caching. 

Here's where I got to be creative with policies.  If a user was authenticated they were to receive non-cached pages(direct from the server), if the user was accessing the site anonymously then they could receive pages that had been cached on WebAccelerator.  Cookies were used to identify whether or not the user was logged in this meant a regular expression was needed.  I am by no means an expert when it comes to regular expressions, however the customer had a team of developers that were.  A quick challenge was presented to the team to create a regular expression that identified whether the value of a cookie met 2 conditions.  It was great to see everybody getting involved in the challenge, in less than 5 minutes I had a working regular expression.  It would have taken me much longer to create this left to my own devices. 

Within an hour we had a policy configured and were ready to test.  Load testing revealed that the application could handle significantly more traffic as the database was not overwhelmed.  An added bonus was the site was faster as well.