Cloud Connector

XDPing PowerShell Function

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I wanted to write valid PowerShell function to do an XDPing the same way Citrix do with their Health Assistant tool. I was struggling a little to get the PowerShell code working as expected, so in the end I used the JetBrains dotPeek .NET decompiler to decompile the VDAAssistant.Backend.dll, which is a component of the Citrix Health Assistant Tool. This allowed me to reverse engineer and understand how Citrix does it in C# .NET, which is then easy for me to convert to PowerShell. Yeah…okay, so I cheated at little 😉 I also released a C# (csharp) function I wrote back in 2020.

I used this PowerShell function in two scripts:

To test if the Broker service is reachable, listening and processing requests on its configured port, you can issue blank HTTP POST requests at the Broker’s Registrar service, which is located at /Citrix/CdsController/IRegistrar. If the first line displayed/returned is “HTTP/1.1 100 Continue“, then the Broker service responded and is deemed to be healthy.

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Controlling the Starting of the Citrix Desktop Service (BrokerAgent)

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UPDATED 17th November 2025

  • Improved the check for the Personality.ini and MCSPersonality.ini files based on the history of VDA changes.
  • Replaced the Get-LastBootTime function with the Get-UpTime function. This starts to phase out the reliance on the Get-WmiObject cmdlet, with preference to use the Get-CimInstance cmdlet.
  • Added a group policy update (gpupdate) to be invoked before it reads the VDAHelper registry values. I’ve
    found this hit and miss with MCS images. So a gpupdate helps to ensures that the registry values are in
    place.
  • Added a check to see if it is a Citrix MCS Master Image. The script will check the following value:
    Key: HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\Configuration
    Type: DWORD
    Value: MasterImage
    Data: 1
    This is important so that it starts the Broker service immediately so that it does not cause any issues
    with the image preparation process.

UPDATED 21st July 2025

  • Added extra error checking and further improved the coding
  • When we set the Winlogon DefaultDomainName value we also need to set AutoAdminLogon value to 0 and clear the DefaultUserName value.
  • If the Winlogon AutoAdminLogon value is 0 (disabled), and the TriggerOnTaskEndEvent is set to 1 (enabled), we change the TriggerOnTaskEndEvent to 0 (disabled). This reduces unnecessary further delay waiting for an event that will never run.

UPDATED 14th July 2025

  • Replaced the Get-DeliveryControllers function with the Get-ListOfDDCs function. The name of the function may have been misleading given that it’s for both Delivery Controller or Cloud Connector addresses. It now allows for the C:\Personality.ini and C:\MCSPersonality.ini for MCS deployments.
  • Added the UsePersonalityini value to the VDAHelper registry values, which is used to call the updated Get-ListOfDDCs function.
  • Updated the XDPing function
  • Changed the flow of some of the code

UPDATED 31st January 2023

  • Added the DefaultDomainName value to the registry, which tells this script to set the Winlogon DefaultDomainName value in the registry once the autologon process has started. This allows us to use a local account for the Autologon process instead of a Domain service account, which won’t work if the Winlogon DefaultDomainName value has already been set to your preferred domain. This reduces the security footprint when using service accounts by allowing us to easily rotate passwords using a local account for the autologon process for each image build. Refer to my article Priming a Non-persistent Windows Image using an Autologon Process with an Auto Logoff Timer to understand how this works.
  • You can now use the policies registry key for the registry settings:
    • Policies Key: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Citrix\VDAHelper
    • Preferences Key: HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\VDAHelper
    • Values set under the Policies key have a higher priority.

UPDATED 30th April 2022

  • Improved the code so that the logon/logoff events are detected more efficiently across all Windows Operating Systems.

UPDATED 17th March 2020

  • Enhanced the checking for the ListofDDCs registry value by also checking the Policies key structure.

UPDATED 18th July 2019

  • The creation of the Scheduled Task needed for this script can be found in the Citrix Virtual Delivery Agent (VDA) Post Install Script. It’s important that the priority of the Scheduled Task is set to normal to prevent it from being queued.
  • Enhanced the Get-LogonLogoffEvent function for backward support of Windows 7/2008R2

UPDATED 16th May 2019

  • Added much more logging with timestamps to help debug issues and correlate events. You’ll see from the screen shot of the log file below that it’s now quite comprehensive.
  • Ensured that the format of the logging timestamp and LastBootUpTime were aligned so that its accuracy can be easily verified as I documented here.
  • Added an XDPing function I wrote to health check the Delivery Controllers.

This is a process I’ve been working on perfecting for a couple of years now. I’ve got it to a point where it works perfectly for my needs, and has been very reliable over the last few months, so I decided it was ready to release to the community.

The challenge has always been that as a Session Host boots up the Citrix Desktop Service (BrokerAgent) starts and registers with the Delivery Controllers before the boot process is complete. Therefore, a user can potentially launch an application/desktop during the tail end of the boot process. When this happens it may fail the session launch, which can leave the Session Host in an unhealthy state, such as a stuck prelaunch state, with the user potentially needing to involve the Service Desk to clear the issue. So managing the timing of the start of the Citrix Desktop Service (BrokerAgent) is extremely important to ensure that your Session Hosts have completed their startup process before registering with the Delivery Controllers. This can be easier said than done!

To add to this complexity, power managed Workstation OS pools can get into a reboot loop if you use an autologon process. I use an autologon process similar to what George Spiers documented in his article “Reduce Citrix logon times by up to 75%“. So if the Session Host has registered with the Delivery Controllers before the autologon process has logged off, the logoff process will trigger another reboot. This can become a real problem to manage.

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