futurebird , We set up a intranet web server for the CS club and it has student sysadmins and they are having so much fun making accounts, and messing with all the settings. I insisted in the server being a literal computer sitting in the corner of a room because I think it helps them to understand how networks work in a more concrete way.
So much of their experience blends internet, virtual machines, etc in ways that might make it harder to imagine making a network from scratch.