Nxserver startup generates 2 sessions (1001, 1003), rather than just one on 1001

[puterboy]

In /usr/NX/etc/server.cfg, I have set (i.e. uncommented) “DisplayBase 1001” — which should corespond to the Linux console :0. So, I would expect that running the NoMachine client would then connect to my existing console session.

However,

• When I run NoMachine client from Windows laptop, I get a new session with DISPLAY=:1003 even though the console (:0) is logged in
• If I then logout of the DISPLAY=1003 session or pre-emptively kill the 1003 session (using /etc/NX/nxserver –terminate 1003), then I get logged into my (existing) console session with DISPLAY=:0 which is the expected behavior with DisplayBase 1001.

This behavior is confirmed by looking at /tmp/.X11-unix. After starting the nxserver service, I get new pipes labeled X1001 and X1003 (corresponding to DISPLAY=:0 and DISPLAY=:1003) corresponding to session 1001 (the console) and 1003 (the newly created session)

So:

• Why is nxserver creating two sessions on 1001 and 1003 rather than just a single session on 1001, corresponding to my already logged-in console session?
• What do I need to do to ensure that only one session corresponding to my value of ‘DisplayBase 1001’ is created?

Note: I am running latest NoMachine 7.10.1 under Ubuntu 18.04.

[Haven]

Hello puterboy,
NoMachine display should not be directly aligned with the physical display. In particular, we should not restring it to a specific number.
To give access to physical display NoMachine is creating a ‘master display agent’. (In your case it would be display 1001.)
Then when the user is connecting we are creating a shadow agent with a new display. (In your case it would be display 1003.)

When NoMachine is selecting free display it considers also other local ports used for internal communication.
DisplayBase should always be considered with DisplayLimit. Search is started with DisplayBase and it is limited by DisplayBase+DisplayLimit value.

[Author]

Posts