Logging into lxplus

I was running the standard checks that Arno gave us to make sure everything is up and running on my computer. I discovered that I couldn’t run “xterm” while connected to lxplus.cern.ch I received the error “xterm Xt error: Can’t open display:”

Thanks to some help from Elim, I found out I was connected via “ssh user@lxplus.cern.ch” whereas I needed to be connected to “ssh -X user@lxplus.cern.ch”. Sure enough, I connected to ssh -X and was able to run “xterm” without a problem.

If you’re having problems with running “xterm”, try this out and see if it works.


2 thoughts on “Logging into lxplus

  1. just -X worked for me too.

    typing “man ssh” into the terminal will bring up a list of all the possible tags as well as the additional info.

    It says,
    “-X Enables X11 forwarding. This can also be specified on a per-host
    basis in a configuration file.

    X11 forwarding should be enabled with caution. Users with the
    ability to bypass file permissions on the remote host (for the
    user’s X authorization database) can access the local X11 display
    through the forwarded connection. An attacker may then be able
    to perform activities such as keystroke monitoring.

    For this reason, X11 forwarding is subjected to X11 SECURITY
    extension restrictions by default. Please refer to the ssh -Y
    option and the ForwardX11Trusted directive in ssh_config(5) for
    more information.

    -x Disables X11 forwarding.

    -Y Enables trusted X11 forwarding. Trusted X11 forwardings are not
    subjected to the X11 SECURITY extension controls.”

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