Connecting to KLC

Connect to KLC with the FastX Desktop Client

The FastX Desktop Client is an application for Microsoft Windows, Mac OS X, and Linux personal computers that makes a network connection to KLC using SSH. It connects you to the Kellogg Linux servers with full graphics support via the Linux X Windows system, also called X11. FastX is made available to members of the Northwestern community under a campus site license.

You will only need to follow the configuration steps the first time you connect to KLC. After FastX is configured you can use it whenever you want to connect to KLC.

Prepare to Use FastX (VPN required for off-campus users)

To download, configure, or connect using FastX from an off-campus location, you must first establishVPN connection. This gives you an authenticated and secure connection to the Northwestern Network that is trusted by the FastX server and by KLC.

Install and Configure FastX

Connect with FastX

Install and Configure FastX

You only need to do the steps in this section once on each computer you want to use to connect to KLC.

Step 1: Download and Install FastX (VPN Connection required)


  1. Download the FastX Installer to your PC.
  2. Run the installer.

Mac OS X:

  1. Download the FastX disk image to your Mac.
  2. Open the disk image named FastX.dmg.
  3. Drag FastX into your Applications folder.


  1. Download the FastX client for Linux.
  2. Extract the tarball and copy the folder to your preferred location, such /usr/local or /opt.

Step 2: Run FastX for the First Time


Use the Start Menu (Click Start Menu > All Programs > FastX) or use the Start Screen to find the FastX application and Run it. When p;rompted, allow FastX to communicate through the firewall.

Mac OS X:

  1. In the Finder, open the Applications folder and locate FastX.
  2. Press the Control-key and click the FastX icon.
  3. Choose Open from the pop-up menu.
  4. Click Open.

Note: FastX will be stored as an exception to your security settings and you will subsequently be able to run it by double-clicking the FastX icon. You will have to do this each time you upgrade FastX.

Step 3: Create a KLC Connection

FastX uses SSH to connect to a KLC node.

1. Click the PLUS icon in the upper right corner of the window.

2. Select SSH from the drop-down list. A New Connection window will open.

3. There are five different machines and you can create a connection for each of the machines, one at a time:

  1. Name: KLC01, KLC02, KLC03, KLC04, or KLC05
  2. Host:,,,, or
  3. Port: 22
  4. UserEnter your own NetID in lower-case letters.

4. Click Save.

5. Click "Continue" when asked about the unrecognized host key.

Connect with FastX

This section shows you how to create a connection to KLC each time you want to connect and how to manage your connections.

Step 1: Open a Connection to a KLC Node

1. With FastX open, double-click one of your KLC connections in the Connections window.

2. A window will pop up. Enter your NetID password. Then click Continue.

FastX will open an SSH connection to KLC and open a Session Management window for KLC. You will have no sessions to begin with, so the window will appear to be empty.

Step 2: Start a Session

1. Click the PLUS icon in the upper right corner of the Session Management window to create a new Session. 

2. A new window will appear. Click the Bookmarks pull down menu and select an application from the drop-down list.

3. The Command box will change to start the application you chose. Your Session Management window will change to show that you have a single session,

and your application will also open:

(Optional) Step 3: Disconnecting and Reconnecting Sessions

It is possible to leave your FastX session running on the server while your client machine is disconnected. This can be useful for running long calculations.  Running sessions are listed in the FastX Session Management window. Sessions continue to run on the KLC node until you terminate them

You can disconnect from a running session without terminating it by selecting the session from the list and then clicking the Pause Button that will appear when a session is selected. You might want to disconnect in your office, go home, and then reconnect. 

You can reconnect to a paused session by double-clicking on the session, or by selecting a session and then clicking the Reconnect Button which looks like “play” button.

If a connection is lost, as in the case of a network failure, the session will disconnect. To re-establish a session after a connection loss, first open a connection to KLC. Your session still will be listed again in the Sessions window.

Step 4: Terminating Sessions

When finished, sessions should be terminated by quitting the application or typing "exit” in the terminal. Sessions can also be terminated from the FastX program by clicking the Blue X Button that appears on the right when a session is selected.

IMPORTANT NOTE: Each of the five KLC nodes has its own list of sessions, so you will have to reconnect to the same node to resume a paused session.