Need help using free load balancer for IIS load balancing.


I am new to KEMP and am trying to get my head round how it works. Basically i have 2 IIS servers hosting multiple sites, each have the FQDN host name in the sites Binding in IIS. and each host the same sites. So i want to be able to load balance accross the two but only using one External IP. I got it working with a L7 NAT but it appeared to be a catch all, so no matter what settings i changed the clients still got the right website.  

How do i modify this so it redirects using the url and isnt a catch all?

I use Ext DNS A records to a single External IP which is NAT FWD'd to the Vservice ip on the LB, I dont want to modify anything on the IIS Servers if possible and also id like to use the WAF feature.

Anyone know of any good guides for the Free Load Balancer thats just for IIS, or any templates i can get?



1 comment

Christian Scheller Official comment

Hello JK,

in a scenario where you publish several name spaces behind one public IP, you can leverage the "Content Switching" feature that allows you to evaluate an inbound request to match pre-defined rules which in turn would steer the traffic accordingly.

In order to set this up, you will need to create a so called SubVS for each virtual destination. So instead of adding real servers to a new virtual service, you would create SubVSs that in turn feature their own "real server". 

Now you have a virtual service with several sub virtual services. Now you will need to create rules to match the inbound traffic. 

Create content matching rules, Header field is "HOST". Create a rule for each FQDN.



Set them to "ignore case".


The next step is associating these rules to the SubVSs. Go to "Advanced Properties" in the top-level virtual service and click the button to enable "Content-Switching" and and additional "rule" field will appear for each SubVS. 

Click the rule field for the first SubVS and you will see a screen where you can select the previously created rules. Select them accordingly.


If things wouldn't work out as expected, go to "System Log Files", "Debug Options" and "Enable L7 debug traces". This will add additional debugging information to the System Message File. If a rule had not been set-up correctly, you will see the line "No suitable destination found" in the System Message File that can be viewed in the browser and will update by pressing F5 (the Internet Explorer would not always work smoothly, use Chrome or Firefox).

This was a simple example for content switching. You can also set-up complex conditional scenarios by using flags, in a way that one specific rule would only fire if another rule had been triggered and set a flag. You have a total of nine flags available.

You can find further information in this document:


Hope this helps, Best Regards

Christian Scheller