Forward X11 applications to a macOS client

Some graphical applications running on a managed Linux clients work well when forwarded to a X11 server on a remote PC. The following example describes the use case to connect from a personal macOS PC to a remote managed Linux PC at ETH and use such an application on it.

Install an X11 server on macOS

Download and install XQuartz on your personal macOS PC

Connect to the ETH network

Make sure you're connected to the ETH network by either:

• WLAN

• or VPN

Configure the X11 server

• Start the newly installed application XQuartz

• In the menu Preferences select Security

  • Activate Authenticate connections

  • Activate Allow connections from network clients

• Restart the xquartz background service either by issuing the following commands in your terminal:

  sudo launchctl unload /Library/LaunchDaemons/org.xquartz.privileged_startx.plist
  sudo launchctl load /Library/LaunchDaemons/org.xquartz.privileged_startx.plist 

  or by restarting your macOS PC

Configure your ssh client

Add the following lines to the file ~/.ssh/config on your macOS PC:

Host <linux_pc>
    User <eth_username>
    Hostname <linux_pc>.ee.ethz.ch
    ForwardAgent yes
    XAuthLocation=/opt/X11/bin/xauth
    ForwardX11 yes
    ForwardX11Trusted yes

Where linux_pc is either the PC you have been assigned for work or one of the student PCs tardis-[a|b|c|d][01-25] and eth_username is your ETH username.

Run a graphical application

• Open a ssh connection to your Linux PC at ETH

  ssh <linux_pc> 

• If you haven't connected to linux_pc, verify the shown SSH host key fingerprint before confirming to accept it's public key:

  The authenticity of host '<linux_pc>.ee.ethz.ch' can't be established.
  ED25519 key fingerprint is SHA256:OFAfZRlkUtvcY6pMkLJGhViGACMc+GFWT7prHEO5Lt8.
  Are you sure you want to continue connecting (yes/no)? yes 

• Start the graphical application you'd like to use from the commandline, for example

  xclock