Enabling X11 Forwarding on Ubuntu 22.04 to Run qluman-qt from a Head Node

Enabling X11 Forwarding on Ubuntu 22.04 to Run qluman-qt from a Head Node

Objective

This article provides step-by-step instructions to enable X11 forwarding on a head node running Ubuntu 22.04 server edition and how to access GUI applications like qluman-qt from a login node using SSH with X11 forwarding.

Edit SSH Server Configuration on the Head Node

Open the SSH daemon config file:
  1. sudo nano /etc/ssh/sshd_config

Ensure the following lines are present and not commented (#):

  1. X11Forwarding yes
X11DisplayOffset 10
X11UseLocalhost no

💡 X11UseLocalhost no is optional but may help in some environments where forwarding does not work properly with localhost.

Save and exit (Ctrl+O, Enter, Ctrl+X).


Restart SSH Service


Apply the changes:
  1. sudo systemctl restart ssh

Confirm Display Environment on the Head Node

Log in directly or via remote terminal to the head node and check the DISPLAY variable:
  1. echo $DISPLAY

Expected output (example):

  1. localhost:10.0

If DISPLAY is set, X11 forwarding is active in your session.

Accessing qluman-qt via X11 Forwarding


From Your Login Node or Workstation

Then connect to the head node with X11 forwarding and launch the application:

  1. ssh -X root@servername qluman-qt
​
Replace servername with your head node’s hostname or IP.

    • Related Articles

    • Accessing Services Running on a Different Network via Jumphost using SSH Local Port Forwarding

      Objective Learn how to access services hosted on a remote network (such as an internal web server or application) from your local machine by leveraging a jumphost (also known as a bastion host) and SSH local port forwarding. What is SSH Local Port ...

    • Configuration to Enable ssh(Remote) Login in Ubuntu.

      How to Enable ssh (Remote) Login in Ubuntu. Have a Trouble to Access ssh Login in Ubuntu. Steps to Configure ssh configuration file. Go to your system/VM and Open Terminal (use ctl+atl+t) and Follow Commands. Open sshd_config file in any editor like ...

    • How to Get Mellanox NIC Details on an Ubuntu Server

      Step 1: List All Mellanox Adapters To find all Mellanox network adapters on your system, run: lspci | grep Mellanox Example output: 04:00.0 Ethernet controller: Mellanox Technologies MT26448 [ConnectX EN 10GigE, PCIe 2.0 5GT/s] (rev b0) Step 2: ...

    • Setup noVNC on Ubuntu 20.04/Gnome 3.36

      VNC (Virtual Network Computing) enables you to control your Linux installation from another computer on the same network, by viewing and interacting with the desktop from the other computer. To learn more about VNC, click here noVNC allows you to ...

    • Mapping mlx5_x Names to Actual InfiniBand Ports

      Purpose In large GPU/AI clusters, each compute node often has multiple InfiniBand (IB) Host Channel Adapters (HCAs). On Linux, these HCAs appear as mlx5_x devices. To troubleshoot connectivity or performance issues, it is essential to map: mlx5_x ...