X11 Forwarding¶

X11 forwarding tunnels the display protocol of individual GUI application windows through an existing SSH connection. No additional client software beyond an X server is required. It is suitable for lightweight applications such as text editors, debugger GUIs, or simple visualisation tools.

Limitations

X11 forwarding uses software-based rendering only and does not support GPU hardware acceleration. It is not suitable for 3D-intensive or high-resolution visualisation workloads. Performance degrades significantly over high-latency connections.

Requirements¶

Linux/macOS: An X server is typically already running. Connect with ssh -X (untrusted) or ssh -Y (trusted) forwarding:
```
ssh -X user@hk2-x86.scc.kit.edu
```
Windows: The recommended option is MobaXterm, which includes a built-in X server and enables X11 forwarding automatically — no additional configuration is required. Simply connect to the login node as described in the MobaXterm documentation and launch GUI applications directly from the shell.

Running GUI applications on compute nodes

To run a GUI application on a compute node, first allocate a node interactively with salloc, then use ssh -X to connect to the allocated node. Alternatively, use one of the VNC-based methods below, which handle this transparently.