VLAB - The technical details

Introduction

VLAB is offered as a way of getting a CSE Computer-lab environment on 'your' PC, Mac or tablet, or even on your phone.

VLAB uses VNC, a Linux equivalent of Microsoft's Remote Desktop or Apple's Screen Sharing.

When you connect to VLAB, you get a CSE Computer-lab environment, in a window on 'your' computer, with access to the exact same software and environment you'll find in CSE labs - from anywhere with Internet access.

VLAB is available to all CSE staff and students, 24-hours a day.

Before you start

A few things to note:

  • VLAB is a new service and a work in progress, details of the service may change over time.
  • Your session will log out automatically if left idle for two hours.
  • When you disconnect, you will be logged out, and any programs you were using will be closed.
  • VLAB connects to your CSE home-directory, and any files you save there, in the same way as a CSE lab-machine.
  • Audio is not supported, and video may be 'choppy' due to network dependent bandwidth limits.
  • You cannot connect USB devices from your own computer to the VLAB desktop
    • You will need to connect to your CSE home directory outside of VLAB if you want to transfer files across.
  • To save network bandwidth, colour depth is set to 16-bit - so graphics-intensive applications, like photo-editing, are not recommended.

Required software

The first thing you will need is a VNC client. There are lots of free ones available, and they should all work with VLAB.

However, we recommend TigerVNC for Windows, Mac and Linux

For iPad and iPhone, we recommend Jump. (And we strongly recommend the use of an external bluetooth keyboard if using a tablet or phone.)

If you will be connecting from outside UNSW, you should also set up a connection to the UNSW VPN.

If you can't install either of these on your computer (for instance, on a shared machine), there are some workarounds, however these are still experimental and may be slower or have reduced availability.

Configuring your VNC client

You need to configure your client not to use VNC authentication, because your login is authenticated inside the desktop session, not through the VNC connection itself.

You should also turn off encryption, as you will be connecting either through directly through UNSW's secure network, or via the UNSW VPN.

Exactly how to set these options is different for every VNC client, however In TigerVNC, you set these options via Options... -> Security:

Connecting to VLAB

  • Connect to the UNSW VPN if you are outside UNSW.
  • Start your VNC client.
  • Select the desktop size you want from the table below.
  • Enter the matching connection string into your VNC client.
  • Click Connect.
  • In the window that appears, log in with your zID and zPass.
  • When you are done, either log out from the desktop or just close the VNC window
  • .
Desktop sizeConnection string
640 x 480vlab.cse.unsw.edu.au:5911
800 x 600vlab.cse.unsw.edu.au:5912
1024 x 768vlab.cse.unsw.edu.au:5913
1280 x 800vlab.cse.unsw.edu.au:5914
1680 x 1050vlab.cse.unsw.edu.au:5915
1920 x 1080vlab.cse.unsw.edu.au:5916
resizeablevlab.cse.unsw.edu.au:5919beta

Note that larger desktop sizes will take more network bandwidth. If your connection is slow, try using a smaller desktop size.

Also note that you can run your VNC client in fullscreen mode, even for small desktop sizes.

Customising your session

The choice of window manager — such as KDE, Gnome, fvwm, enlightenment, twm, fluxbox, etc., etc., etc. — which starts up on your screen when you log in to any CSE lab machine is controlled by the .xsession file in your home directory. If there is no .xsession in your home directory then a default window manager will be started for you.

Because VLAB is intended to run on screens with a far greater variety of resolutions than CSE's own lab computers, we have configured it to use a separate .xsession-vlab file. This allows you to have a full-featured window manager such as Gnome when you're in a CSE lab, and a separate, simpler window manager when you're connecting from a tablet or mobile phone with a much smaller screen.

If you have no .xsession-vlab file, VLAB will prompt you to select a window manager and will then use a default configuration.

Below are two sample .xsession-vlab files to get you started:

#!/bin/sh # Starts VLAB with the Gnome window-manager exec gnome-session #!/bin/sh # Starts VLAB with fvwm (using the server's default configuration) exec fvwm -f /etc/X11/fvwm2rc-vlab

Note that the file needs to be executable, so run chmod a+x .xsession-vlab after you've created the file.

Screenshots of VLAB in action

On Windows 10:

1024x768 vlab screen on Windows 10

On a UNSW Library PC:

1024x768 vlab screen on UNSW library computer

On an iPad:

iPad: 1024x768 desktop

Known issues

  • Although the servers all run 64-bit kernels, they only have 32-bit libraries installed. This means that they only fully support 32-bit applications, with a maximum of 4GB of memory per process. (You can actually run 64-bit applications, but they need to be statically linked.).
  • Google Chrome does not work and is not installed.

Workarounds and Advanced Options

There are some workarounds and experimental features that can allow you to connect without the use of a VPN or VNC client.

All of these methods may be slower, more complicated or be less available than the normal methods of connecting to VLAB, but they should get you up and running if you need to.

Connecting without a VPN client

If you can't use the UNSW VPN for whatever reason, you can still get access to VLAB.

Using your web browser

There is a web interface to VLAB; it's still in the experimental phase and will always be somewhat slower than normal methods, but it will work in a pinch.

Just browse to https://vlabgateway.cse.unsw.edu.au and log in as normal.

Direct encrypted connection using TigerVNC

This only works with the TigerVNC client, as encrypted connections are not a standard VNC feature:

  • Enable TLS with anonymous certificates in the Options... -> Security dialog (see above)
  • Connect to vx0.cse.unsw.edu.au:5920

SSH Tunnel

If you can connect to CSE over SSH, then you can create an SSH Tunnel, as a kind of limited VPN into our network.

Using PuTTY on Windows

  • Find the connection string you want to use for your preferred window size. In this example, we'll be using vlab.cse.unsw.edu.au:5912, but you can choose any of them (and change the port numbers to match)
  • Start up PuTTY.
  • Go to Settings -> Connection -> SSH -> Tunnels
  • Enter the connection string in the Destination box.
  • Enter the port number (5912 in this example) into the Source port box.
  • Ensure Local and Auto options are selected.
  • Click Add.
  • Scroll back up to the Session menu, and login as normal to login.cse.unsw.edu.au
  • Once you're logged in via SSH, open your VNC client and connect to localhost:5912.
  • Don't close or log out of SSH until you're done, or you will disconnect from VLAB.

Using ssh on Mac or Linux

  • Find the connection string you want to use for your preferred window size. In this example, we'll be using vlab.cse.unsw.edu.au:5912, but you can choose any of them (and change the port numbers to match)
  • add -L 5912:vlab:5912 to the end of the SSH command line.
  • For instance: ssh z1234567@login.cse.unsw.edu.au -L 5912:vlab:5912
  • Log in with your zID and zPass.
  • Open your VNC client and connect to localhost:5912
  • Don't close or log out of your SSH session until you're done, or you will disconnect from VLAB.

Connecting without a VNC client

If you can't install a VNC client on your computer for some reason, you can use the web-interface at https://vlabgateway.cse.unsw.edu.au.

Last edited by pmr 27/07/2017

Tags for this page:

virtual, remote, vlab, vnc, labs