Nutanix and Citrix–Better together

Now Citrix has for a long time, support for most of the different hypervisors. Meaning that customers gets the flexibility to choose a number of different hypervisors if they are planning to use XenApp/XenDesktop. This support is also included for Netscaler as well.

So as of today, Citrix supports XenServer, Hyper-V, Vmware, Amazon, Cloudplatform. As well as Azure support is on the way. Meanwhile a month back, Citrix announced a partnership with Nutanix, and stating that Acropolis Hypervisor was Citrix ready for XenApp/XenDesktop and Netscaler and Sharefile as well. This means that the customers will get a better integration between the hypervisor as well as support for the product on the Nutanix Hypervisor.

Kees Baggerman from Nutanix posted this teaser on his website. Of how the integration might look like


Now this is mostly focused on the Citrix Workspace Cloud, but also stated that this is coming for tradisional on-premises XenApp/XenDesktop as well


Also looking forward to the deeper integration with for instance Machine Creation Service with for instance Shadow Clones on the Acropolis Hypervisor!

Optimizing web content with Citrix Netscaler

This post, is based upon a session I had for a partner in Norway. How can we use Netscaler to optimize web content?

Let’s face it, the trends are chaging

* Users are becoming less patient (meaging that they demand that applications/services respond quicker. (more then 40% of users drop out if the website takes mroe then 5 – 10 seconds to load) think about how that can affect a WebShop or eCommerce site ?

* More and more mobile traffic (Mobile phones, ipads, laptops. Communicating using 3G/4G or WLAN for that matter) and to that we can add that there is more data being sent across the network as well. Site web applications become more and more complex, with more code and more components as well.

* More demands to availability (Users are demaing that services are available at almost every hour. If we think about it about 5 – 10 years ago, if something was down for about 10 min we didn’t think that much about it, but now ?

* More demands to have secure communication. It wasn’t that long ago that Facebook and Google switched to SSL as default when using their services. With more and more hacking attempts happening online it requires a certain amount of security.

So what can Netscaler do in this equation ?

* Optimizing content with Front-end optimization, Caching and Compression

With the latest 10.5 release, Citrix has made a good jump into web content optimization. With features like lazy loading of images, HTML comment removal, minify JS and inline CSS.  And adding it that after content is being optimized the content can be compressed using gZIP or DEFLATE and sent across the wire (NOTE: that most web servers like Apache and IIS support GZIP and Deflate but it is much more efficient to do this on a dedicated ADC)

And with using Caching to store often accessed data it makes the Netscaler a good web optimization platform.

* Optimizing based upon endpoints.

With the current trend and more users connecting using mobile devices which are using the internett with a wireless conenction. If needs a better way to communicate as well. A god example here is TCP congeston. On a wireless you have a higher amount of packet loss and this requires using for instance TCP Congestion Westwood which is much better suites on wireless connections. Also using features like MTCP (on supported devices) allows for higher troughput as well. And that we can place different TCP settings on different services makes it much more agile.

* High availability

Using features like load balancing and GSLB allows us to deliver a high availabilty and scale solution. And using features like AppQOE to allows us to prioritize traffic in a eCommerce setting might be a valuable asset. Think the scenario if we have a web shop, where most of our buying customers come from a regular PC while most mobile users that are connecting are mostly checking the latest offers. If we ever where to reach our peak in traffic it is useful to prioritize traffic based upon endpoint connecting.

* Secure content

With Netscaler it allows us to create specific SSL profile which we can attack to different services. For instance older applications which are used by everyone might not have the high requirement regarding security, but on the other hand PCI-DSS requires a high level of security. Add to the mix that we can handle many common DDoS attacks on TCP level and on HTTP. We can also use Application firewall which handles many application based attacks, when an own learning feature it can block users which are not following the common user pattern on a website. And that we can specify common URLs which users are not allowed to access.

So to summerize, the Netscaler can be a good component to optimizing and securing traffic, with a lot of exiting stuff happening in the next year! Smilefjes stay tuned.

Setting up a secure XenApp enviroment–Storefront

So this is part two of my securing XenApp enviroment, this time I’ve moved my focus to Storefront. Now how does Storefront need to be secured ?

In most cases, Storefront is the aggregator that allows clients to connect to a citrix infrastructure. Im most cases the Storefront is located on the internal network and the Netscaler is placed in DMZ. Even if Storefront is located on the internal network and the firewall and Netscaler does alot of the security work, there are still things that need to be take care of on the Storefront.

In many cases many users also connect to the Storefront directly if they are connected to the internal network. Then they are just bypassing the Netscaler. But since Storefront is a Windows Server there are alot of things to think about.

So where to begin.

1: Setting up a base URL with a HTTPS certificate (if you are using a internal signed certificate make sure that you have a proper set up Root CA which in most cases should be offline. Or that you have a public signed third party CA. Which also in many cases is useful because if users are connecting directly to Storefront their computers might not regonize the internally signed CA.


2: Remove the HTTP binding on the IIS site. To avoid HTTP requests.

Use a tool like IIS crypto to disable the use of older SSL protocols on IIS server and older RC ciphers


You can also define ICA file signing. This allows for Citrix Receiver clients which support signed ICA files to verify that the ICA fiels they get comes from a verified source.

3: We can also setup so that Citrix Receiver is unable to caching password, this can be done by changing authenticate.aspx under C:\inetpub\wwwroot\Citrix\Authentication\Views\ExplicitForms\

and you change the following parameter

<% Html.RenderPartial(«SaveCredentialsRequirement»,
              SaveCredentials); %>

<%– Html.RenderPartial(«SaveCredentialsRequirement»,
                SaveCredentials); –%>

4: Force ICA connections to go trough Netscaler using Optimal Gateway feature of Storefront –> using this option will also allow you to use Insight to monitor clients connection to Citrix as well, and depending on the Netscaler version give you some historical data.

And with using Windows pass-trough you can have Kerberos authenticating to the Storefront and then have ICA sessions go trough the Netscaler –>

5: Use SSL in communication with the delivery controllers –>

6: Install Dynamic IP restrictions on the IIS server, this stops DDoS happning against Storefront from the same IP-address

 IIS fig4

7: Windows updated!  and Antivirus software running (Note that having Windows updated, having some sort of antivirus running with limited access to the server) also let the Windows Firewall keep runnign and only open the necessery ports to allow communication with AD, Delivery Controllers and with Netscaler.

8: Define audit policies to log (Credential validation, Remote Desktop connections, terminal logons and so on)

9: Use the Storefront Web Config GUI from Citrix to define lockout and session timeout values


10: Use a tool like Operations Manager with for instance ComTrade to monitor the Storefront Instances. Or just the IIS management pack for IIS, this gives some good insight on how the IIS server is operating.

11: Make sure that full logging is enabled on the IIS server site.

IIS Logging Configuration for System Center Advisor Log Management

Stay tuned for more, next part is the delivery controllers and the VDA agents.

Setting up a secure XenApp enviroment– Netscaler

Now I had the pleasure of talking PCI-DSS compliant XenApp enviroment for a customer. Now after working with it for the last couple of days there are lot of usefull information that I thought I would share.

Now PCI-DSS compliance is needed for any merchant who accepts credit cards for instance an e-commerce size. Or using some sort of application. So this includes all sorts of

* Different procedures for data shredding and logging

* Access control

* Logging and authorization

Now the current PCI-DSS standard is in version 3 –>

The different requirements and assesment procedures can be found in this document. Now Citrix has also created a document for how to setup a compliant XenApp enviroment you can also find some more information here –>

Now instead of making this post a pure PCI-DSS post I decided to do a more “howto secure yout XenApp enviroment” and what kind of options we have and where a weakness might be.

Now a typical enviroment might looks like this.


So let’s start by exploring the first part of the Citrix infrastructure which is the Netscaler, in a typical enviroment it might be located in the DMZ. Where the front-end firewall has statefull packet inspection to see what traffic goes back and forth. The best way to do a secure setup of Netscaler is one-armed mode and use routing to backend resources and then have another Firewall in between to do deep packet inspection.

First thing we need to do with Netscaler when setting up Netscaler Gateway for instance is to disable SSL 3.0 and default (We should have MPX do to TLS 1.1 and TLS 1.2 but with VPX we are limited to TLS 1.0

Also important to remember th use TRUSTED third party certificates from known vendors, without any known history. Try to avoid SHA-1 based certificates, Citrix now supports SHA256.

Important to setup secure access to management only (since it by default uses http)


This can be done by using SSL profiles which can be attached to the Netscaler Gateway


Also define NONSECURE SSL renegotiation. Also we need to define some TCP parameters. Firstly make sure that TCP SYN Cookie is enabled, this allows for protection against SYN flood attacks and that SYN Spoof Protection is enabled to protect against spoofed SYN packets.


Under HTTP profiles make sure that the Netscaler drops invalid HTTP requests


Make sure that ICA proxy migration is enabled, this makes sure that there is only 1 session at a time established for a user via the Netscaler


Double hop can also be an option if we have multiple DMZ sones or a private and internal zone.

Specify a max login attempts and a timeout value, to make sure that your services aren’t being hammered by a dictonary attack


Change the password for the nsuser!!!


Use an encrypted NTP source which allows for timestamping when logging. (Running at version 4 and above) and also verify that the timezones are running correctly.


Sett up a SNMP monitoring based solution or Command Center to get monitoring information from Netscaler, or use a Syslog as well to get more detailed information. Note that you should use SNMP v3 which gives both Authentication and encryption.

Use LDAPS based authetication against the local active directory server, since LDAP is pure-text based, and use TLS not SSL, and make sure that the Netscaler verifies the server certificate on the LDAP server


It also helps to setup two-factor authentication to provide better protection against user thefts. Make sure that if you are using a two factor authentication vendor that it uses CHAP authentication protocol instead of PAP. Since CHAP is much more secure authentication protocol then PAP

Use NetProfiles to control traffic flow from a particular SNIP to backend resources (This allows for easier management when setting up firewall rules for Access.


Enable ARP spoof validation, so we don’t have any forging ARP requests where the Netscaler is placed (DMZ Zone)


Use a DNSSEC based DNS server, this allows for signed and validated responses. This way you cannot its difficult to hijack a DNS or do MITM on DNS queries.  Note that this requires that you add a nameserver with both TCP and UDP enabled. (Netscaler can function as both a DNSSEC enabled authoritative DNS server and proxy mode for DNSSEC)

If you wish to use Netscaler as an VPN access towards the first DMZ zone, first things you need to do is

1: Update the SWOT library


Create a preauthetnication policy to check for updated antivirus software


Same goes for Patch updates


In most cases try to use the latest firmware, Citrix does release a new Netscaler firmware atleast one every three months which contains bug fixes and security patches as well.

Do not activate enhanced authentication feedback, this enabled hackers to learn more about lockout policies and or if the user is non existant or locked out, disabled and so on.


Set up STA communication using HTTPS (Which requires a valid certificate and that Netscaler trusts the root CA) You also need to setup Storefront using a valid certificate from a trusted Root CA. This should not be a internal PKI root CA since third party vendors have a much higher form a physical security.

If you for some reason cannot use SSL/TLS based communication with backend resources you can use MACSec which is a layer 2 feature which allows for encrypted traffic between nodes on ethernet.

Citrix XenMobile and Microsoft Cloud happily ever after ?

There is no denying that Microsoft is moving more and more focus into their cloud offerings, even with solution such as Office365, EMS (Enterprise Mobility Suite) and of course their Azure platform.

EMS being the latest product bundle in the suite gives customers Intune, Azure Rights Management and Azure Active Directory Premium. So if a customer already has Office365 (their users are already placed with Azure AD and can then easily be attached to EMS for more features)

We are also seeing that Microsoft is adding more and more management capabilities against Office365 into their Intune suite (Which is one of the keypoints which no other vendors have yet) but is this type of management something we need ? or is it just to give it a “key” selling point?

Now Microsoft has added alot of MDM capabilities to Intune, but they are nowhere close to the competition yet. Of course they have other offerings in the EMS pack, like Azure Rights Management, which are quite unique on the way it functions and integrates with Azure AD and Office365. As of 2014 Microsoft isn’t even listed on the Gartner quadrant for EMM (which they stated would be the goal for 2015)

But it will be interesting to se if Microsoft’s strategy is to compete head-to-head on the other vendors or if they wish to give the basic features and dvelve more into the part of Azure AD and identity management across clouds and SaaS offerings.

Citrix on the other hand, have their XenMobile offering which is a more complete EMM product suite (MDM and MAM, Follow me data with Sharefile, and so on) Now Citrix has a lot of advantages for instance over using Sharefile against OneDrive.  Sharefile has encryption of data even thou it is locally and running on a sandboxed application( on a mobile device), while the only option that OneDrive has is using as a part of Rights Management Service (of course OneDrive has extensive data encryption in-transit and at rest

Citrix also has MicroVPN functionality and secure browser access running VPN access using Netscaler, while Microsoft also has a secure browser application which is much more limited to restricting which URLs to open and what content can be viewed from that browser.

So from a customer side you need to ask yourself.

  • what kind of requirement does my buisness have?
  • Do I use Office365 or a regualr on-premise setup?
  • Do I need the advanced capabilities ?
  • How are my users actually working ?

Is there a best of both worlds using both of these technologies ?

While yes!

Now of course there are some feature that overlaps using Offic365 and EMS + XenMobile, but there are also some features which are important to be aware of.

* Citrix has Sharefile storage controller templates in Azure (Meaning that if a customer has an IaaS in Azure, they can setup a Sharefile connector in Azure and use that to publish files and content without using OneDrive)

* Citrix has a Sharefile connector to Office365 (Which allows users to use Sharefile almost as a file aggregrator for communicating between Office365 and their regular fileservers) which allows for secure editing directly from ShareFile.

* Citrix XenMobile has alot better MDM features for Windows Phone that Intune has at the moment.

* Azure AAD has a lot of built-in SSO access to many of Citrix web based applications (Sharefile, GTM, GTA and so on) since users are already in Azure AD premium it can be used to grant access to the different applications using SSO)

* Netscaler and SAML iDP (If we have an on-premise enterprise solution we can use the Netscaler to operate as an SAML identity provider against Office365 which allows for replacement for ADFS which is required for full SSO of on-premise AD users to Office365

* Office365 ProPlus with Lync is supported on XenApp/XD with Lync optimization pack (Note that this is not part of XenMobile but of Workspace suite)

* Netscaler and Azure MFA (We can use Azure MFA against Netscaler to publish web based applications with traffic optimization)

* Netscaler will also soon be available in Azure which allows for setting up a full Citrix infrastructure in Azure

But in the future I would be guessing that Microsoft is moving forward with the user collaboration part, it is going to become the heart of identity management with Azure AD directory and rights management, while Citrix on the other hand will focus more and enabling mobility using solutions like EMM ( MAM ) and follow me data aggregator and secure file access and devices. Citrix will also play an important part in hybrid setup using Netscaler with Cloud bridge and as an identity provider on-premise

“New” Netscaler book project in the making

Now the last couple of months I’ve again been involved with a Netscaler book project with Packt. This is a more advanced book then my previous book with was a more introduction to Citrix Netscaler.

This new book is called Mastering Netscaler which has more in-depth information regarding load balancing, appfirewall and such.

But… I kinda feel that this book just covers a fragement on what users want to read about when they buy a book about Netscaler.

Therefore in order to get things right, I was thinking about creating a third book about Netscaler which covers all the subjects, stuff you want to read about. Therefore this post is merely for you to give feedback to me Smilefjes

If you could please give me a few senteces about what YOU would want to include in a Netscaler book ? Please drop a comment below this post.

and if you are willing to help me form and maybe contribute to the outline and possibly help me write the book as well that would be great, just send me email to

Upcoming events and stuff

There’s alot happening lately and therefore there has been a bit quiet here on this blog. But to give a quick update on what’s happening!

In february I just recently got confirmation that I am presenting two session at NIC conference (Which is the largest IT event for IT-pros in scandinavia) ( Here I will be presenting 2 (maybe 3) sessions.

* Setting up and deploying Microsoft Azure RemoteApp
* Delivering high-end graphics using Citrix, Microsoft and VMware

One session will be primarly focused on Microsoft Azure RemoteApp where I will be showing how to setup RemoteApp in both Cloud and Hybrid and talk a little bit about what kind of use cases it has. The second session will focus on delivering high-end graphics and 3d applications using RemoteFX (using vNext Windows Server), HDX and PCoIP and talk and demo abit about how it works, pros and cons, VDI or RDS and endpoints so my main objective is to talk about how to deliver applications and desktops from cloud and on-premise…

And on the other end, I have just signed a contract with Packt Publishing to write another book on Netscaler, “Mastering Netscaler VPX” which will be kind of a follow up of my existing book

Which will focus more in depth of the different subjects and focused on 10.5 features as well.

I am also involved with a community project I started, which is a free eBook about Microsoft Azure IaaS where I have some very skilled norwegians with me to write this subject. Takes some time since Microsoft is always adding new content there which needs to be added to the eBook as well.

So alot is happening! more blogsposts coming around Azure and Cloudbridge.