X11 forwarding request failed on channel 0

Make your Linux connection using ssh

ssh -Y user@linux.system.address

This will automatically setup an X11 tunnel, initialize the DISPLAY environment variable that will look something like localhost:10

YOU MUST NOT, define your own DISPLAY environment variable. ssh will do that, if you do your own define in your shell initialization scripts will destroy what ssh has setup.

You DO NOT need xauth.

I have used XQuartz and ssh -Y for years to my Linux hosted development system, and it works great.

After I make a connection, I do make sure it is working by running xclock on the remote Linux system, as it is a quick and easy way to verify the ssh X11 tunnel is properly established and is talking to XQuartz on my Mac.

If you have JUST installed XQuartz, you will need to either logout of the Mac GUI and login again, or just reboot, so that XQuartz will establish the necessary hooks into the GUI environment that allows it to open and display windows, and to pass the local DISPLAY information to ssh.

ssh -C -Y user@linux.system.address

The -C is compression.

I do not use X11 all that often, but my company has an X11 source code control merge conflict resolution tool, and it helps to have that vectored back to my Mac.

I have found that the distance between my Mac and the Linux system matters (more than bandwidth). In my case, my Hosted Linux development system is about 2,000 miles away, and the lag time adds up when you are going through multiple router hops between me and the development system.

ALSO, some X11 based apps are very chatty, and send lots of little messages to do anything. These X11 apps tend to be slow and sluggish from 2,000 miles away. Other apps are less chatty (gvim for example), and from 2,000 miles away, it is mostly usable (still a little lag, but not terrible).

Then again, when the Linux system is in the same building and accessible over gigabit Ethernet with very few router hops between my Mac and the Linux system, the X11 apps are rather responsive. Even the excessively chatty ones.

If I have to do a lot of X11 based work on a Linux system, I'll fire up a TigerVNC session on my Mac and connect to the Linux system. It seems to work better 2,000 miles away than X11. But most of my work can be done via ssh connections, so I rarely fire up TigerVNC. I have used other VNC clients over the years, but I've found TigerVNC does the best with Copy & Paste between Linux and my Mac.