LightDM (Lightweight Display Manager) is a Display Manager for the X server. It is the default X display manager of Ubuntu. LightDM starts an X session and presents the user with a graphical login screen, so the user does not have to issue commands such as `startx` to start the X server

LightDM is the default X display manager of Ubuntu. It starts the X server, user sessions and greeter (graphical login screen).

Key Features of LightDM:

  • Cross-desktop - supports different desktop technologies.
  • Supports different display technologies (X, Mir, ...).
  • Lightweight - low memory usage and fast performance.
  • Low code complexity
  • Supports remote login (incoming - XDMCP, VNC, outgoing - XDMCP, pluggable).
  • Easily themeable
  • Support for 3D
  • Offers guest sessions.

To understand more about LightDM and its role in the Ubuntu login process you may refer to this answer.

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