Hi IlNeofita,
You can disable access to specific user, using rules, e.g.
sudo /usr/NX/bin/nxserver –ruleadd –class node –type localhost:4000 –value no –user <username>
Server management using rules is available on enterprise versions. If you have a free version, you can limit access for selected users using NoMachine database. To enable it, edit server configuration file /usr/NX/etc/server.cfg. Uncomment and change values of two keys:
EnableUserDB 1
EnablePassDB 1
Then you can add users who will be able to connect using command:
sudo /usr/NX/bin/nxserver –useradd <username>
Please refer “Users Management” for details:
https://www.nomachine.com/DT02O00125#9.6