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Connecting to RC Systems§

After you have applied for and been granted access to our services, you can log in using a terminal application that supports the ssh access protocol.

Aristotle is a teaching machine accessible to everyone with a UCL user ID and does not need to be applied for.

Logging in from Linux or Mac OS X§

Use the terminal and run the below command to ssh into the correct machine. Replace ccaaxyz with your central UCL username.









You will then be asked to enter your UCL password. This user ID and password are those provided to you by Information Services Division.

If you will want to run graphical applications, read on to "Running graphical applications using X-forwarding".

Logging in from Windows§

On Windows you need something that will give you a suitable terminal and ssh - usually PuTTY, although you could also use Cygwin if you wanted a full Linux-like environment.

Using PuTTY§

PuTTY is a common SSH client on Windows and is available on Desktop@UCL. You can find it under Start > All Programs > Applications O-P > PuTTY

You will need to create an entry for the host you are connecting to with the settings below. If you want to save your settings, give them an easily-identifiable name in the "Saved Sessions" box and press "Save". Then you can select it and "Load" next time you use PuTTY.

Replace "legion" in the hostname with "myriad", "grace", or "aristotle" as appropriate.

Putty GUI

You will then have a screen come up that asks you for your username and password. Only enter your username, not "". The password field will remain entirely blank when you enter it - it does not show placeholders to indicate you have typed something.

Login problems§

If you experience difficulties with your login, please make sure that you are typing your UCL user ID and your password correctly.

If you still cannot get access but can access other UCL services like Socrates, please contact us on

If you cannot access anything, please see UCL MyAccount - you may need to request a password reset from the Service Desk.

Accessing services from outside UCL§

If you wish to access any of our machines from outside UCL, you cannot do so directly as they are behind UCL's firewall. To do so you will have to either use ssh to connect to UCL's gateway first:


and from there connect to the correct host as described above, or login first to your departmental gateway (if you have one) and then login from there.

IS VPN Service§

Alternatively, you can use the ISD VPN service to connect to UCL using a virtual private network. This makes your computer a part of the UCL network, once the connection has been established, so you can establish an ssh connection to the host machine directly, for example:


Running graphical applications using X-forwarding§

X-forwarding allows users to run a graphical program on a remote computer and display the user interface on their own computer.

X-forwarding on Linux§

If you wish to have X-windows functionality enabled you have to make sure that you add either the -X or -Y flags (see man ssh for details) on all ssh commands you have to run to establish a connection to Legion.

For example:

ssh -X

To use X-Forwarding from outside UCL, you must either use the VPN, or the appropriate flags with both ssh steps, for example:

[me@my_computer ~]$ ssh -X
[ccaaxyz@socrates-a ~]$ ssh -X

X-forwarding on Mac OS X§

You will need to install XQuartz to provide an X-Window System for Mac OS X. (Previously known as

You can then follow the Linux instructions using the Mac OS X Terminal.

X-forwarding on Windows§

You will need:

  • An SSH client; e.g., PuTTY
  • An X server program; e.g., Exceed, Xming

Exceed is available on Desktop@UCL machines and downloadable from the UCL software database. Xming is open source (and mentioned here without testing).

Exceed on Desktop@UCL§

  1. Load Exceed. You can find it under Start > All Programs > Applications O-P > Open Text Exceed 14 > Exceed
  2. Open PuTTY (Applications O-P > PuTTY)
  3. In PuTTY, set up the connection with the host machine as usual:
    1. Host name: (for example)
    2. Port: 22
    3. Connection type: SSH
  4. Then, from the Category menu, select Connection > SSH > X11 for 'Options controlling SSH X11 forwarding'
    1. Make sure the box marked 'Enable X11 forwarding' is checked.
  5. Return to the session menu and save these settings with a new identifiable name for reuse in future.
  6. Click 'Open' and login to the host as usual
  7. To test that X-forwarding is working try one of these test applications:
    1. nedit: a text editor
    2. xeyes: to bring up a set of eyes that track the mouse position on the screen
    3. glxgears: to bring up an animated set of gears
    4. xclock: a clock

If these work, you have successfully enabled X forwarding for graphical applications. (Note they may not be available on all systems).

Installing Xming on your own computer§

Xming is a popular open source X server for Windows. These are instructions for using it alongside PuTTY. Other SSH clients and X servers are available. We cannot verify how well it may be working.

  1. Install both PuTTY and Xming if you have not done so already. During Xming installation, choose not to install an SSH client.
  2. Open Xming - the Xming icon should appear on the task bar.
  3. Open PuTTY
  4. Set up PuTTY as shown in the Exceed section.

Transferring files§

Read on to Managing data on RC systems.