Unable to connect or reconnect to Windows XP Virtual Desktops, and Event ID: 1102 is logged in the Application Log of the Desktop Delivery Controller, with the following description:

"The Citrix Broker Service failed to broker a connection for user 'UserName' to resource 'Desktop Group'. The virtual machine 'Virtual Machine Name' rejected a request to prepare itself for a connection. This problem usually indicates that the virtual machine is engaged in an activity such as restarting, entering a suspended state, or processing a recent disconnection or logoff."

Workstation Agent log contains the message "PortICA SetListening to True has failed" to indicate the failed connection attempt.
 

Caution! Using Registry Editor incorrectly can cause serious problems that might require you to reinstall your operating system. Citrix cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. Be sure to back up the registry before you edit it.

The solution for this issue is to reserve the ICA ports in the registry to prevent a range of ports from being assigned during a wildcard bind. So the Citrix ICA Service direct request for 1494 or 2598 is not affected.
 
Caution! Refer to the Disclaimer at the end of this article before using Registry Editor.
 

1. Run regedit.exe.

2. Navigate to the following registry subkey:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

3. Create a new Multi-string Value named ReservedPorts.

4. Edit the ReservedPorts value, and type 1494-1494.

5. Start a new line and type 2598-2598.

6. Click OK.

7. Close Registry Editor and restart the virtual desktop.

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Problem Cause

The random ephemeral port range for Windows XP starts at 1025-5000, any process can use the ports 1494 and 2598 to form a TCP connection. XenDesktop does not listen for a connection until a user session is initiated, which stops the ICA Service from being able to start listening.
 
Note: This workaround only applies to Windows XP Virtual Desktops, as Windows Vista and later use the range 49152 to 65535 as suggested by the Internet Assigned Numbers Authority (IANA).
 

Users necting to XP Virtual Desktops might randomly be unable to connect to XenDesktop sessions, with Event ID 1102 recorded on the event log of the Desktop Delivery Controller.

Windows TCP/IP Ephemeral, Reserved, and Blocked Port Behavior

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