We're big fans here of the iRules 20 Lines or Less series for F5's BIG-IP. LineRate proxy uses a Node.js scripting engine embedded into the HTTP data path, so we can't directly use iRules scripts. However, the power and flexibility of the Node.js engine allows us to do some pretty cool things - and a lot of these things don't require much code and can be implemented quickly.

The LineRate Lightning series will contain snippets of code that aim to be quick, powerful and maybe a little bit flashy - kind of like real lightning!

lightning-fist-blue

If you want to know more about scripting, be sure to check out the official documentation and the LineRate Scripting Guide. And remember that the F5 LineRate staff monitors DevCentral closely so this is a great place to get all your questions answered.

If you're already a LineRate user, you have a good handle on what we can do with scripting. If you're not, this will be a great way for us to show you. Sit back and hold on while we ride the lightning.


This first snippet is a simple one that does HTTP referrer blocking based on a whitelist of permitted referrers.

Simply add the refering domains that you'd like to permit in the domain_whitelist list and change vs_http to match the name of your virtual server.

Here's the script: