Xming 7 5 0 30 Setup 15

which means it doesn't have a correct path to the xauth program. (On this version of macOS the path to xauth is nonstandard.) The solution was to add this line to /etc/ssh/ssh_config (may be /etc/ssh/config in some setups) or in /.ssh/config (if you don't have admin rights):

xming 7 5 0 30 setup 15

My goal was get quiet ssh-based command line login t Linux hosts from my macOS client. E.g. I didn't want to see any banners or messages. Just setup cert-based login so I could type an alias at the and get a prompt on the host machine. To accomplish that I did the following: 350c69d7ab