http://www.nomachine.com/

There is a known limit to the number of users for the free version of NX:

NoMachine version is limited to two 'named' users. To check or change these,
nxserver --userlist, nxserver --useradd, nxserver --userdel. These will have
been the first two users to connect.

Cheers
Euan

On 10/16/06, Maccy <[email protected]> wrote:
> Hi,
>
> I'm experiencing a very strange problem whereby newly created users are
> not able to connect to a machine via NX but users that have been
> registered on my systems for a while can log in no problem.
>
> They get the message 'Reached the maximum number of allowed users on
> this server' even though no-one else is logged on!
>
> There is no known difference between the newly-created linux accounts -
> we're using Scientific Linux 4.3 (RHEL clone) - and the experienced user
> accounts.
>
> I've tried....
>
> a) Removing the key in .ssh/known_hosts on the client
> b) Removing the .nx directory from both client and on the server
> c) Rebooting and reinstalling the server
> d) Recopying server SSH keys
> e) Multiple clients and servers
>
> I've even tried copying the entire contents of an experienced user's
> home directory over to the new accounts.
>
> We're currently using the free version of the server from nomachine.com
> whilst we wait for unlimited licence keys.
>
> Does anyone have any further suggestions?
>
> Many thanks in advance,
>
> Mark

See kde_preferences_in_rhel5_for_better_performance for speeding up KDE sessions with NX.

13 August 2012 - Bug with "System" menu locking up NX session:

https://bugzilla.redhat.com/show_bug.cgi?id=730378 and http://bugs.centos.org/view.php?id=3796

27 March 2013

When connecting to a RHEL6.4 machine running the NoMachine software, the keyboard mapping may be incorrect. Specifically the "Take Screenshot" is mapped to the delete key. To fix this, after connecting to the target machine via NX and establishing a GNOME session, go to System > Preferences > Keyboard Shortcuts and change the "Take a screenshot" shortcut to Ctrl+Print. The fix should "stick" after logging out and logging back in. Note, RHEL7 MATE the menu is in System > Preferences > Hardware > Keyboard Shortcuts.

The working package in RHEL6.3: xkeyboard-config-2.3-1.el6.noarch.rpm
The problematic package in RHEL6.4: xkeyboard-config-2.6-6.el6.noarch.rpm

16 April 2014

Useful links:
http://wiki.centos.org/HowTos/FreeNX
https://www.nomachine.com/getting-started-with-nomachine