Accessing CSE login servers

The CSE login servers

If you are away from CSE and want to access your CSE home directory, or run many of the programs installed on CSE managed systems, CSE runs a number of login servers for this purpose.

To access these servers, you will need an SSH client. If you want to run programs with a graphical user interface you need to run an X-Server on your local computer.

SSH is a very useful tool for creating secure connections between computers. Normally you would connect to one of our main login servers which have the hostname You may be permitted to log into other CSE login servers such as Grieg or cluster computers.

At the time of writing CSE has two login servers for general work: wagner and weill. We recommend you use these for logging in to read email, move files, submit marks or assignments, compile programs and such.

A third login server, williams, is available for running sustained computing tasks. We recommend you use that for running simulations or processing data with Matlab, etc.

The three servers, Wagner, Weill and Williams, are shared resources and should be available for everyone at CSE to use. If you run programs that take up most of the memory, CPU or network bandwidth of those computers then this stops other people using them. In that case your programs will be killed by System Support and you will be asked to be more considerate.

CSE also runs Terminal Servers (Windows Servers) for staff and researchers to use.

Username and password

As of Session 1 2014, your zID and zPass should be used to authenticate your CSE account.
Your username is made up of a 'z' followed by your 7 digit ID.

Logging in from Linux

Simple Text Programs

You may just want to check your CSE home directory, compile a program, remove a few files, run priv commands or a text mode mail client such as mutt or pine. You can do these things with a text mode SSH connection. From a terminal window, type:ssh (replace username with your zId or your CSE username if you have been issued one.) After entering the appropriate password, you will now be logged on to one of the login servers. You may now run commands like priv commands, acc commands and many others.

X-Windows Programs over SSH

If you are running a graphical user interface such as gnome, kde or similar, you have everything you need. From a terminal window, type:ssh -Y (replace username with your zId or your CSE username if you have been issued one.) After entering the appropriate password, you will now be logged on to one of the login servers. You may now run commands like gedit, ical, tkrestore and many others.

Logging in from Mac OS X

If you want to login to run command line software you can use "Terminal" which is in /Applications/Utilities. For GUI software you will need to install XQuartz so you have X Windows. You will have an XQuartz icon in the Applications/Utilities Folder. If you launch this, you should get a terminal window. If you don't see one, select it from the X11 menu at the top of the screen. To connect to the CSE login servers, run:ssh -Y (replace username with your zID (or CSE account name if you have been issued a named account) Enter your password and you may now run commands like ical, priv commands, acc commands and many others.

Logging in from Windows

To connect to CSE servers from Microsoft Windows you will need to install and configure a Secure Shell (SSH) client (eg: PuTTY) on the local computer. Microsoft Windows does not natively support the CSE graphical interface (X11); if you wish to run applications which rely on a graphical interface (eg: gedit) you will also need to install and run an X-Server (eg: Xming) on the local computer.

What is PuTTY?

PuTTY is a Windows SSH client which gives you a terminal window, not unlike the CSE laboratories environment. PuTTY can be downloaded from the CSE software mirror.

What is Xming?

Xming is a standalone open-source X-Server for Windows. Programs that use a graphical user interface require an X-Server on your home computer. Xming can be found on the CSE software mirror, in addition to an optional fonts package.

Installing PuTTY and XMing

Run the setup program(s) for PuTTY and Xming. We suggest that you choose the default options for the installation, and choose the options to create icons for PuTTY and Xming on the desktop. Xming should be running before you run PuTTY: when it is running, you will see an X icon in the system tray (bottom right hand corner of your Windows screen).

Configuring PuTTY and XMing

When you run PuTTY for the first time, you will see a window like the one below.

  1. In the box below Host Name (or IP Address) enter If the lecturer for your subject has suggested you use a specific server, enter it instead. For more information about CSE servers and their uses see:
  2. Make sure SSH is selected.
  3. Enter in the box below Saved Sessions.
  4. Click the [-] to expand SSH from the window on the left (if necessary) and click X11. You should see this screen. Ensure that the checkbox for Enable X11 forwarding is selected.

    After you have clicked the check box, scroll the left hand window back to the top and click on the Session heading. You should see the same screen as in Step 1.
  5. Click the Save button. The host name you entered should now appear below Default Settings. In the future, you will be able to connect by simply double-clicking this host name.
  6. Click the Open button.
  7. If you see a window like this: click the Yes button.

  8. When you see: login as: enter your zId (in the form z1234567)
  9. When you see:’s password: enter your zPass. This should remotely log you into your CSE account.

Persistent Logins

You can login and run programs on a remote computer, then disconnect from it, and reconnect later.

Text terminals using screen

The program screen is useful for managing terminal sessions. From Wikipedia:
Screen is often used when a network connection to the terminal is unreliable, as a dropped network connection typically terminates all programs the user was running. Running the applications under screen means that the applications don't even know the terminal has detached, and allows the user to reattach the session later and continue working from where they left off.
Debian provides a quick, helpful guide to using screen:
…Essentially GNU Screen is a windowing system for the console. When you run it inside an xterm, or a remote SSH login, you can create multiple new windows all in the same session, switch between them, or view two or more at once. In addition to this a screen session is independent of your connection, so you can connect from one location, run things inside a screen session then detach. All the programs keep running and you can later reconnect and resume working right where you left off. It's the attaching and detaching that makes screen so useful as it allows you to start long running programs, leave them running in the background and later on come back to them. If you run screen … [then] … press space and you will be presented with what looks like an ordinary shell window. … Now we get to see the power of the program. Press Ctrl+A, then d. You will see a message saying that your screen session has been detached, and will be back at your original prompt.… So what happened to your shell? Well it's still there! Simply run screen -R and you will be back at the session you detached from.

GUI desktop using VNC

You might find it easier, particularly if you plan on running long graphical jobs, to use VNC to gain a virtual screen on one of the CSE computers. Instructions on using VNC can be found on this taggi page.
Last edited by pmr 03/08/2016

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