Hi graywolf,
i don’t think so.
NoMachine v. 5 no longer requires to manually install a display server like Xvfb: when the local X server cannot be found, NoMachine will use its own display service (that is an embedded X server) to let users connect seamlessly a physical desktop running in background on the remote machine.
https://www.nomachine.com/AR10K00710
Maybe i’m missing some packages? I have a fresh installation of Ubuntu Server, just installed SSH server.