---
title: "X11 forwarding"
description: "Display graphical applications from CARC machines on your local screen with X11 forwarding."
type: Guide
tags:
  - SSH
  - Visualization
generated:
  by: "claude/fable-5"
  at: "2026-08-29T00:00:00Z"
sources:
  - id: quickbytes
    resource: "https://github.com/UNM-CARC/QuickBytes/blob/master/X11_forwarding.md"
    title: "UNM-CARC QuickBytes: X11_forwarding.md"
    author: "team:unm-carc"
    last_modified: "2026-06-17T14:15:52-06:00"
---

# 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](https://www.xquartz.org){target=_blank} before using X11 forwarding. You can install it in one of two ways:

**Option 1 — Download the installer** from [xquartz.org](https://www.xquartz.org){target=_blank} and run the `.dmg` package.

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

```bash
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](https://github.com/XQuartz/XQuartz/releases){target=_blank} to confirm your macOS version is supported before installing.

## On a PC (Windows)

Download and install [MobaXterm](https://mobaxterm.mobatek.net){target=_blank}. 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:

```bash
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:

```bash
touch ~/.Xauthority
```

Then log out and back in before continuing.

### 2. Start an interactive session with X11 forwarding

```bash
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.

```bash
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:

```bash
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](../training/videos.md):

<iframe class="carc-video" src="https://www.youtube-nocookie.com/embed/-5ic9JWHuqI" title="X11 Forwarding" loading="lazy" allow="accelerometer; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>

<p class="carc-provenance" markdown>Migrated from [UNM-CARC QuickBytes](https://github.com/UNM-CARC/QuickBytes/blob/master/X11_forwarding.md){target=_blank} (last source update 2026-06-17). Spotted a problem? [Open an issue or pull request](https://github.com/UNM-CARC/QuickBytes){target=_blank}.</p>