VNC access via an SSH tunnel

Tags: Faq

If you’re running a Linux system with a VNC server on campus (e.g. after following these instructions) you’ll need to access it via an ssh tunnel. This page gives basic instructions on connecting for various operating systems.

N.B. If accessing from off campus, you will first need to have your VPN connection up and running.

Windows
Linux
MacOS

Windows

First off, of course, you need to download and install the following pieces of software: VNCViewer and PuTTY
Next, configure an ssh tunnel using PuTTY. Start the application and enter the DNS name of your Aber PC into the “Host Name” (you can find that by visiting this page from your Aber PC) and “VNC Tunnel”, for example, into the “Saved Sessions” box:

Expand “SSH” in the left hand tree and click on “Tunnels”:

Enter 5900 into the “Source port” box and “localhost:5900” into the “Destination” box. Then click on “Add”:

Next, return to the “Sessions” page (scroll up the menu tree to find it) and click “Save”:

If all is working, you should then be able to double click on “VNC Tunnel” in the “Saved Sessions” list and log into your PC:

You don’t need to enter anything into the Putty session window - its only job is to provide the tunnel that VNCViewer needs. So you can minimise (not close) the window.
Next, open VNCViewer and type “localhost:0” into the text box:

Hit Enter and you should then be presented with the usual Linux login screen.
The desktop may give you a warning about a lack of hardware acceleration and that the system may be slow as a result. This is because you’re not connected to a “real” graphics card. You can safely ignore this.

Linux

I recommend using “Remmina”, which should be available in your distro’s standard repositories and which has a VNC plugin that supports ssh tunnelling directly.

Configure a VNC connection to your_pc_dns_name:0 (replacing your_pc_dns_name with the name of your PC. You can find out what that is by visiting this page from your Aber PC.

Click on the “SSH Tunnel” tab and click “Enable SSH tunnel”.

MacOS

MacOS has built in support for VNC, but does not natively support ssh tunnelling. You can get around this by establishing the tunnel by hand.

Open a terminal and run:

ssh -f -L 5910:localhost:5900 your_username@your_pc_dns_name sleep 60

replacing your_username with your Aber account name and your_pc_dns_name with the name of your PC. You can find out what that is by visiting this page from your Aber PC.

Next (within 60 seconds), run:

open vnc://localhost:5910