Q: How do I get X working over ssh when connected to a linux machine?

A: At a eg Cygwin command prompt enter "ssh -X This email address is being protected from spambots. You need JavaScript enabled to view it.92.168.0.9.
 
In Cygwin the /etc/X0.host should contain the remote server name.
 
The remote server should have the local machine's name in /etc/X0-host.