I decided to run an X Server on my Windows 10 laptop. I only need it for Cognos gateway configuration, but when you need it, you need it. Of course an X Server listens on port 6000, so hosts outside of your PC have to be able to initiate a TCP connection to your PC with destination port 6000. So that port has to be open. The software I use for the X Server is Mobatek XTerm.
Here is the Powershell command to disable the block of TCP port 6000.
New-NetFirewallRule -DisplayName "MobaXterm Allow Incoming Requests" -Direction Inbound -LocalPort 6000 -Protocol TCP -Profile Domain -Action Allow
The Powershell window needs to be run as administrator. The change is permanent: it suffices to run it once.
And, because inquiring minds want to know, did it work? Yes, it worked and I could send my cogconfig X window to my Mobatek X Server. I had to look for a new Window. It was slow.