FastX is a commercial tool for rendering graphical output from remote Linux servers.  It is a faster alternative to traditional remote display using SSH with the X11 protocol.   Software on the remote system writes to a virtual display, which is mapped to the desktop display using a protocol more like a video stream than X11. FastX displays may be disconnected and reconnected while not interrupting the remote processes.

Software that is optimized for local display on a Linux workstation, such as rstudio, can have much higher performance using FastXor may be completely incompatible with traditional remote X11. FastX is recommended for the graphical interfaces to rstudio, matlab, mathematica, idl, SAS, stata, spss, and similar software.

FastX displays output in your web browser and can connect to remote servers that have the FastX software installed.  These include Andes, Polaris, and Discovery.  Licensing is by number of concurrent connections.

Official documentation for the FastX Browser client is at


  1. In a browser tab, open an HTTPS connection to a server on port 3443. In other words, one of these URLs.
  2. Enter your NetID and password to login into the FastX session manager on the Linux system. Do not select public key authentication; it will not work correctly.

  3. Once logged in, you will see large icons for any running sessions that you already have. You can reconnect to these by clicking on the icon.  You can also create new sessions with the blue button that looks like a plus sign.  Here is an example of the session manager window showing an XFCE session (a full Linux desktop), an xterm session (just a terminal window), and above those the blue + icon for creating new sessions.

  4. To create a new session, click the blue + button and you will see three predefined bookmarks: a Gnome session (Linux desktop; not usually recommended because it is very resource intensive), an XFCE session (lightweight Linux desktop), and an xterm (terminal from which you can run other commands).  Select one and press the "Launch" button.  Note: You can also run commands directly from the "Command" tab. Connecting to a session will open a new tab in your web browser.  You may have to tell your web browser to allow this. That's it!

Changing your preferences (eg. keyboard layout)

Once an xterm, XFCE or Gnome session has been started, you will be able to change your preferences and access the drop-down menu at the middle of the window. To deploy the menu, hover-over the light-gray bar at the top-center of the window to un-hide the "home", "keyboard", "folder" and "preferences" icons (see red circle in screen shot below):

Clicking on the "keyboard" icon will deploy a menu of all available keyboard layouts:

Logging out of a session

Unless you explicitly need to come back to the same session later on, e.g. if you have left a computation running in the session, it is important to log out of the session when you are done to free up the resources (memory, licenses, etc.) used by your session.

  • For an xterm session, that means typing "logout" in the terminal. 
  • For an XFCE session, right click on the desktop, select "Applications", and then "Log Out".

Disconnecting from a session

Close the FastX browser tab(s) to disconnect from your session.  Your processes are still running on the server and you will be able to reconnect to them later.  Be aware that sessions which remain idle for more than a couple days (i.e. have been in a disconnected state and are not obviously utilizing CPU cycles anymore) can be automatically terminated to free up resources.


Article ID: 81595
Mon 6/24/19 6:04 PM
Mon 9/20/21 8:22 AM