Change VLAN assigned to a Citrix XenDesktop/XenApp 7.x Hosting Resource

I created a hosting resource in Citrix Studio, then needed to change the VLAN I associated with it. This apparently can't be done from within Studio, but can be done with a PowerShell command. Here is what I did to change the assigned VLAN:

First, I created a new resource with the correct network VLAN so I could have it for reference.

From the Citrix Delivery Controller server, I ran PowerShell as Administrator, then typed the following commands:

Add-PSSnapin *Citrix*
Get-Item 'XDHyp:\HostingUnits\NAMEOFCORRECTRESOURCE'

This gave me information about the new, correct resource I created. I copied the value of the "NetworkPath" for the resource, then ran the following command on the resource I wanted to change:

Set-Item 'XDHyp:\HostingUnits\NAMEOFRESOURCE' -NetworkPath 'PASTEPATHHERE'

That's all I had to do! New VMs created using that resource are now using the new VLAN.

Error 25703 When Installing or Uninstalling Citrix XenApp 6.5 Components

I recently needed to uninstall Citrix XenApp 6.5 from a server, but the uninstall failed with this error:

Error 25703. An error occurred while plugging XML into Internet Information Server. Setup cannot copy files to your IIS Scripts directory. Please make sure that your IIS installation is correct.

The only Citrix tool I know of that can configure XML is the command line tool "ctxxmlss.exe", so I ran that with the "/u" parameter, which basically disables XML and unregisters it. As soon as I did that I tried uninstalling the hotfix again, and it worked!

Of course, if your Citrix XenApp farm relies on XML, you will need to reconfigure it after you install or uninstall whatever you need to.

Enable Seamless Windows in XenApp 6.5 To Use Custom Window Color Scheme

After migrating an application from XenApp 5 on Windows Server 2003 to XenApp 6.5 on Windows Server 2008 R2, I got complaints from end users that the color scheme for their application on the new servers was hurting their eyes.

It turned out that the default grey color used by Server 2008 is lighter than in 2003, and it strained the eyes of the users and made it more difficult to see objects, such as text boxes, on the screen. After finding documentation on Citrix.com about a registry entry called SeamlessFlags, I added the value that is supposed to allow synchronizing of the system colors with the colors in the Citrix session, but it did not work. I actually found two separate Citrix KB articles with conflicting values. One said to use a hex value of 0x10 and another said 16 in decimal. Neither one worked.

I then downloaded a utility from Citrix called FarmTWIHelper, which is a GUI that helps configure the Seamless flag settings. I set the "Enable Color Sync" value, which added a value to the registry of 10 in hex and 16 in decimal, like I tried before. This still did not work.

I ended up playing with different settings and setting the decimal value to 10 (a in hex) finally worked, although I'm not sure why:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Citrix\wfshell\TWI]

"SeamlessFlags"=dword:0000000a

Now I use a group policy to set the color values in HKEY_CURRENT_USER\Control Panel\Colors. The only problem I am still having is getting the custom colors to apply on a user's first logon. Currently, the user gets the default colors first, but the custom colors on all future logons.

References:
Seamless Configuration Settings
http://support.citrix.com/article/CTX101644

Case Study: Troubleshooting Seamless Flag - Custom Application
http://support.citrix.com/article/CTX127043

FarmTWIHelper - Seamless Configuration Helper Tool
http://support.citrix.com/article/CTX115146

Increase Session Graphics Memory Limit

I recently found out that the maximum memory limit for Session Graphics in Citrix XenApp 5 on Windows Server 2003 can be increased above the 8 MB limit that is seen in the Delivery Services Console. Here is a link to the Citrix document explaining how to increase the limit: http://support.citrix.com/article/CTX114497

Basically, all you need to do is change the value "MaxLVBMem" located at "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\Wds\icawd\thin16" to a higher number. I used the decimal value of 16777216 and this allowed 16-bit color for applications at much higher screen resolutions than before.

After making the change, you must also change the permissions on the "thin16" key to deny "set value" access to the SYSTEM account. This prevents the SYSTEM account from changing the value back to a lower limit.

Web Interface Trusted Sites Issue

My company uses a Citrix Secure Gateway server with the Citrix Web Interface installed on the same server. If the address of the gateway is not in the end user's Trusted Sites list when using Internet Explorer, the user gets a message telling them how to add it.

However, since the Secure Gateway uses the address "localhost" to communicate with the locally installed Web Interface, the address the user is told to add to their trusted sites is http://localhost. This confuses some users, and if they follow the instructions it won't fix the problem. I needed a way to change the address to the actual URL of our Secure Gateway. Here's how to fix the problem:

1. Back up the file changeZoneHelp.inc (the default location is: C:\Inetpub\wwwroot\Citrix\XenApp\app_data\clientDetection\include), and open with Notepad. Add the following line after line 1 (replace with your URL):
<% viewModel.siteURL = "https://csg.company.com/"; %>
2. Restart the Citrix Secure Gateway service (this will close any open sessions).

That's it! The users should now see the correct URL.

Citrix "Protocol Driver" error when launching an application

One of our Citrix Xenapp 5 servers wouldn't allow applications to be launched, giving a "protocol driver" error. After following the instructions on Citrix's web site (http://support.citrix.com/article/CTX108698) and rebooting the server, the server started working again.

Here are the steps I took, in short:

1. Disabled session reliability for the server in the Citrix Delivery Services Console
   
2. Deleted the ICA-tcp connection in Terminal Services Configuration on the effected server
   
3. Recreated the ICA-tcp connection
4. Re-enabled session reliability
5. Rebooted the server

I didn't have to recreate the LHC like the Citrix article says.

Manually Remove A Server From A Citrix Farm

When I tried to use the Citrix management console to remove an old server from my Presentation Server 4.0 farm, I got an error that said: "The Presentation Server Console failed to remove the server. Error Code:80000007"

Since using the console didn't work, I had to use the dscheck utility provided by Citrix to manually remove the server from the datastore. Here is the command to use, where servername should be replaced with the name of the server you want to remove from the farm (CAUTION: If you don't specify a server name, ALL servers in the farm will be deleted!):

dscheck /full servers /deleteall servername

Citrix Web Interface 5.2 and Presentation Server 4.0

We are currently in the process of migrating from Citrix Presentation Server 4.0 to XenApp 5.0 FP2, and have applications published from both farms.

I recently upgraded our Citrix Web Interface servers from version 5.11 to 5.2. It was a very simple, quick upgrade. However, after the upgrade, nobody could launch applications from servers running Presentation Server 4.0.

The problem ended up being that version 5.2 of the Web Interface does not support Program Neighborhood Agent/XenApp Plugin connections to 4.0 farms by default. I spent quite a while reading through the instructions, but missed that information somehow. There is one line in the WebInterface.conf file that has to be manually edited in order to enable connections to 4.0 farms:

To configure support for Presentation Server 4.0, Presentation Server 4.0 for UNIX, and XenApp 4.0 for UNIX

Updated: 2009-09-07

In this example, you want to configure a site for compatibility with Citrix Presentation Server 4.0, Citrix Presentation Server 4.0 for UNIX Operating Systems, and Citrix XenApp 4.0, with Feature Pack 1, for UNIX Operating Systems. New Web Interface sites are not initially compatible with these products—an additional manual site configuration step is required.

1. Using a text editor, open the WebInterface.conf file and locate the following line:

   RequireLaunchReference=On

2. Change the setting to Off, as follows:

   RequireLaunchReference=Off

   Note: Setting the RequireLaunchReference parameter to Off disables pass-through authentication to XenApp VM hosted apps. Users of this site will be required to enter their credentials each time they access a VM hosted app.

Here are some links to information on this issue:

Citrix support forum thread: http://forums.citrix.com/message.jspa?messageID=1410690
Citrix Web Interface 5.2 documentation: http://support.citrix.com/proddocs/index.jsp?topic=/web-interface-gransden/wi-server-requirements-gransden.html
Workaround for problem: http://support.citrix.com/proddocs/topic/web-interface-gransden/wi-configure-support-cps-4-gransden.html

I would like to know why Citrix didn't make this vital information more visible, instead of tucking it away in a tiny section of the server requirements section of their online documentation. It would have been nice if they included at least a warning, if not a option to enable 4.0 access, in the Web Interface 5.2 install wizard, rather than relying on the customer to manually edit the configuration file.

Passthrough in Web Interface 5.x

I was going crazy trying to figure out how to get applications to launch with the credentials of the user that was logged on to the Web Interface. Passthrough worked fine for the initial logon to Web Interface, but after that a Windows logon box appeared for each application that was launched.

Apparently there is no way to configure this in the Access Management console. However, I did finally find a way to modify the default.ica file (located at "C:\Inetpub\wwwroot\Citrix\XenApp\conf\" in my environment) to allow full passthrough.

Assuming you have already enabled passthrough authentication to the Web Interface web site in the Access Mangement console, simply add the following lines under the [WFClient] section in the default.ica file:

EnableSSOnThruICAFile=On
SSOnUserSetting=On

Do this for every Web Interface server and it should work immediately!

Quickly unpublish and publish applications in Citrix XenApp

I have been looking for an easy way to stop users from connecting to a Citrix XenApp server without actually disabling logons completely. I found the answer in another blog and thought I'd share it here as well.

http://www.virtualpro.co.uk/2008/09/29/citrix-unpublish-applications-script/