It's possible to configure the NoMachine server to forbid that its host machine is added to NoMachine Network.

To do that, set the following key in server.cfg:

EnableNetwork 0

and restart the server or run 'nxserver --configupdate'.

On the client, it's possible disable Network-related features in the interface (the Network login will not show and previously launched Network connections will be disabled).  This requires some changes in the player.cfg by setting the following key to "false":

`<option key="Enable NoMachine Network features and interface" value="false" />`

Quit the Player, edit the cfg and save, reopen the NoMachine application.