X11 forwarding to Mac does not work

Try running ssh -Y root@xxxx in xterm inside XQuartz instead of from iTerm. Does that work?

open /etc/ssh/sshd_config in remote system and set X11Forwarding yes . Then restart ssh service and try again

Correct me if I am wrong. You want to access your machine running Ubuntu remotely from your mac and when you 'ssh' into your Ubuntu and when you try to 'echo $DISPLAY' you get an empty response. Probably the following solution might not work in your case, but give it a try if what you were trying is similar to what I have tried.

As you have already found one has to find the DISPLAY variable first.

So in your mac if you type as a normal user

echo $DISPLAY 

Then what you would get is something like the following (It is the case in your hand). Anyway you all would see something similar in your systems.

/private/tmp/com.apple.launchd.0aQYNoXMFK/org.xquartz:0 

Then try something like

xeyes 

And now you know that your display is working

Now if you want to try the same as root (Please don't jump on me guys, I know some of you all are strongly against root access), but if does not work then in your root prompt do the following

export DISPLAY=/private/tmp/com.apple.launchd.0aQYNoXMFK/org.xquartz:0 

The same you found in your normal user account. Then copy your '.Xauthority' at '/Users/normal user/.Xauthority' to '/var/root/'. The .Xauthority file is already there, but this would over right it.

cp /Users/normal user/.Xauthority /var/root/ 

Of course the export might work, but there is no harm in doing the above. Now try the following.

echo $DISPLAY 

And you should see the following

/private/tmp/com.apple.launchd.0aQYNoXMFK/org.xquartz:0 

If you 'ssh' into Ubuntu from normal user prompt then you do not need to do the root part, but since, I use root to 'ssh' my Ubuntu systems I often have to do this.

Then when you 'ssh into Ubuntu type

echo $DISPLAY 

And you would see something like the following

localhost:10.0 

The above would work if you have done all those other bits like forwarding and etc.

Again, if you want to use root in your Ubuntu and if the 'echo $DISPLAY' does not produce any response, then try the following (Assuming you are at root prompt).

cp /home/user name/.Xauthority /root/.Xauthority 

Now try

echo $DISPLAY 

again and you would see something like the following

localhost:10.0 

For fun try

xeyes 

And it works in my case. Hope this is helpful and would solve a problem like the one above or like mine that someone has come across and who spent a few hours on this problem while scratching head and trying to pull hair out like me :-)).

After trying a lot of different options, this is what worked for me:

On my Mac:

I first launch xQuartz. Then I go to my terminal and run export DISPLAY=localhost:0.

On my remote linux PC:

I had issues with wayland so I went to /etc/gdm/custom.conf and uncommented the line WaylandEnable=false. I also set export XAUTHORITY=$HOME/.Xauthority. And lastly, I set export QT_QPA_PLATFORM=xcb which is what made some graphical libraries is python work.

After setting this up, you can now ssh into your remote server using ssh -Y remoteserver@IP and hopefully this should work.