Laptop partly broken, Xdmcp to the rescue

My laptop took a header onto the floor and the corner of the case is
smashed up. If it is pressed back into shape, the monitor turns off
– this makes it hard to type on.

Since the desktop configured just the way I like it as well as a
chroot debian/unstable environment for building debian packages I
wanted a way to get to the laptop from my other work (Compaq Deskpro
EN running Red Hat 8.0) and other home systems (specifically my wife’s
Microsoft Windows 2000 laptop + cygwin).

The solution was to enable Xd
mcp
on the laptop and then connect to
it from the other system’s X servers. Here are the steps.

  • On the laptop which uses kdm, edit /etc/kde2/kdmrc and look for
    the [Xdmcp] section and enable it. The line looks like this

    [Xdmcp]
    ...
    # Whether KDM should listen to XDMCP requests. Default is false for Debian.
    Enable=true
    ...
    
  • Now edit /etc/kde2/kdm/Xaccess to allow access. Uncomment the two
    lines that look like this:

    ...
    *                                       #any host can get a login window
    ...
    *               CHOOSER BROADCAST       #any indirect host can get a chooser
    ...
    

    You can tighten up security by enumerating all the systems you want
    access from. Since both of the networks my laptop connects to (home
    behind a NATting firewall and work’s corpnet) are secure enough for me
    so I didn’t bother.

  • Now restart kdm on the laptop, “/etc/init.d/kdm restart”

  • From the linux desktop, startup X and have it connect to my laptop’s XDMCP:

    X -broadcast -query mylaptop.name :1
    

    And in a few seconds there is the familar KDM login on ALT-F8.

  • From the Microsoft Windows 2000 desktop that has cygwin installed,
    startup X and have it connect to my laptop’s XDMCP:

    X -broadcast -query mylaptop.name :1
    

    And in a few seconds there is a window that contains the
    familar KDM login.

  • Performance is acceptable across WiFi.

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One Response to “Laptop partly broken, Xdmcp to the rescue”

  1. Mark Fink Says:

    Thanks marc for your bloc. I think the section about the /etc/kde2/kdm/Xservers file is missing. without an entry in the form IP/Servername:0 foreign for each terminal the configuration will not work.

    Cheers, Mark.

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