Front End Optimization (FEO) on Citrix NetScaler 11


Last update: July 7th 2018
(FEO testpage does not exist any more, but I updated the download link)

I played round on my Citrix NetScaler with Front End Optimization (FEO) in NetScaler 11 built 63.16 (October 2015).

There are several requirements. First of all, FEO is a feature depending on an other feature: Integrated Caching. Integrated Caching has to be set up properly, I have written a blog posting recently about how to set up Integrated Caching for Front End Optimization. You will see only particular success if you fail to set it up correctly.

I then set up a testing environment. It’s a quite simple web page. It’s sad but true: this web page is not a peace of art, but it got everything in it it takes to test FEO.

I have to write some words about this web page before going into NetScaler’s Front End Optimization.

My test page

You can download my test page from

My web server has 6 different virtual directories pointing to the same physical directory: /feotest, /feotest1, /feotest2, /feotest3, /feotest4, /feotest5. This is done using virtual directories on my web server, not on NetScaler.
I agree: it’s a mess, but it took me some while to stuff that many mistakes into a single HTML file.

The web page is well documented (look at the source of the web page). There is a menu bar on top, containing several small GIF pictures. There is – of course – a home GIF, the view unoptimized page GIF (original), 5 different optimization settings (compress) and there is a view source GIF (viewsource). This view source GIF calls a Java script ( It’s quite simple, but good enough for us. The reference to this script is the first line in the head partition.

This test page calls 2 CSS file (norz.css, default.css). These style sheets are conflicting. One of them is on the bottom of the HTML page.

Both, js scripts and CSS are well documented and well structured, to show optimization features.

The page contains several JPG, PNG and GIF pictures. These pictures are also improperly formatted, i.e. some of them contain EXIF tags. They are not optimized in any way.

There are 5 optimization settings, all of them are well documented on the page itself.

How to use my test page

I tend to use Firefox, but similar tools are also shipped together with Internet Explorer and Chrome. Start Firefox, press the F12 key, the network analysis tool pops up. Press Shift F5 (to reload the page and avoid caching). You’ll see something like this:

(this is an unoptimized version of the web page)

Remember the size of the objects, loading time, location and names. You may view the page source at any time if you press the spanner symbol (viewsource).

(this is a version, optimized for domain sharding [option 5])

Keep the network analysis tool open and try several settings on my web page. You’ll see the effect (and some times changing objects) in the size column.

Citrix NetScaler Set Up for Front End Oprimization

I already mentioned the importance of Integrated Caching. It’s very likely caching if your setup does not work as expected.

For reasons of clarity and comprehensibility I created a separate load balancing vServer for this test. Beside to the fife Front End Optimization policies there are no other policies bound to it but policies removing caching related HTTP headers both in request and response.


I created 5 FEO policies and filtered them on the name of the virtual subdirectory, something like


This guarantees all media content in the same (virtual) directory and all it’s subdirectories is affected by the same policy.


Screen-shots of the Front End Optimization Policy actions can be found on my test page.

You may download my test page from here.

I hope you like it and would appreciate your comets.

Credits: Thanks to TWiki for all these GIFs!

About the author

Johannes Norz

Johannes Norz is a Citrix Certified Citrix Technology Advocate (CTA), Citrix Certified Instructor (CCI) and Citrix Certified Expert on Application Delivery and Security (CCE-AppDS).

He frequently works for Citrix international Consulting Services and several education centres all around the globe.

Johannes lives in Austria. He had been borne in Innsbruck, a small city (150.000 inhabitants) in the middle of the most beautiful Austrian mountains (


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