X11 forwarding¶

X11 Forwarding allows any graphical user interface to open on your local machine while the software itself is being run on a CARC cluster compute node. This QuickByte will show you how to set up and use X11 forwarding.

On a Mac¶

macOS does not include an X11 server, so you will need to install XQuartz before using X11 forwarding. You can install it in one of two ways:

Option 1 — Download the installer from xquartz.org and run the .dmg package.

Option 2 — Install via Homebrew (if you have Homebrew installed):

brew install --cask xquartz

After installing, log out and back in before using X11 forwarding.

Note: If you are on the latest version of macOS, check the XQuartz releases page to confirm your macOS version is supported before installing.

On a PC (Windows)¶

Download and install MobaXterm. It combines an SSH client, X server, and file transfer client into one application and handles X11 forwarding automatically — no additional configuration required. The free Home Edition is sufficient for CARC use.

Step by Step Example of X11 Forwarding with MATLAB¶

1. Log in to Easley with X11 forwarding enabled¶

For Mac, launch XQuartz, then open a terminal from the 'applications' menu. Use the -Y flag when connecting via SSH to enable trusted X11 forwarding:

ssh -Y username@easley.alliance.unm.edu

Note: -Y (trusted forwarding) is recommended over -X (untrusted forwarding) as it works more reliably across different system configurations, but if one doesn't work, try the other. Also note that X11 forwarding requires a native terminal with XQuartz (Mac) or MobaXterm (Windows) — it will not work from the OOD web terminal at ood.alliance.unm.edu.

If you get the error "/usr/bin/xauth: file /users/user/.Xauthority does not exist", run:

touch ~/.Xauthority

Then log out and back in before continuing.

2. Start an interactive session with X11 forwarding¶

srun --x11 --pty bash

3. Load and launch MATLAB¶

Once you have been assigned a node, load the MATLAB module and start MATLAB. The GUI should automatically open on your local machine.

module load matlab
matlab

4. Use the MATLAB GUI¶

Use the MATLAB GUI to load your add-on or run your application as you normally would.

5. Exit when finished¶

When you are finished, close the GUI by clicking the X. Then, exit the interactive session to release the node for other users:

exit

Video Tutorial¶

A CARC QuickByte video on X11 forwarding is available here: https://www.youtube.com/watch?v=-5ic9JWHuqI&list=PLvr5gRBLi7VAzEB_t5aXOLHLfdIu2s1hZ&index=12

If you have any trouble at any point, please reach out to us at help@carc.unm.edu

This quickbyte was validated on 6/17/2026

Video walkthrough¶

X11 Forwarding — from the CARC video tutorials:

Migrated from UNM-CARC QuickBytes (last source update 2026-06-17). Spotted a problem? Open an issue or pull request.