When refreshing agent cache from Citrix WEM Console, the console freezes and have to kill and re-connect to get it working again.



The issue happens only if specific agent machines are selected for the refresh cache action.

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Resolution is to modify the default dynamic TCP port range as below.

1. Run below command and confirm the existing dynamic range on the machine.

netsh int ipv4 show dynamicport tcp

2. If the range is not default (Start Port : 49152 & Number of Ports : 16384), some other application might have modified your default range (example some SQL server components does this).
3. Change the starting IP of this range to 49753, so that lsass.exe or other similar apps will not use WEM port 49752. By doing so, we are skipping 601 ports at the beginning of the range, so the "Number of ports" has to be reduced by 601, and to be entered as 15783.

netsh int ipv4 set dynamicport tcp start=49753 num=15783

4. Verify the dynamic port range after the change:

5. A reboot is required for this change to be effective as per Microsoft articles.

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Problem Cause

WEM Agent Service should be listening on port 49752 for accepting the refresh signal from WEM Broker Console.



However, if any other process (example lsass.exe) is listening on this port instead of WEM, the issue occurs.



To verify this situation, run below query on WEM Agent and check the output.

Get-NetTCPConnection | Select-Object -Property *,@{'Name' = 'ProcessName';'Expression'={(Get-Process -Id $_.OwningProcess).Name}} | where {$_.localport -eq "49752"} | select processname, state, localport, remoteaddress, remoteport | ft -auto

Expected output: 


An example for problem situation:


The reason for this behavior is, port 49752 falls under the default dynamic TCP port range and can be consumed by other processes as it is not reserved for WEM.

Because of this issue, WEM Broker console hangs as the refresh signal to agent is not getting completed.

https://learn.microsoft.com/en-US/troubleshoot/windows-server/networking/default-dynamic-port-range-tcpip-chang