NX Server and NX Client are commercial products, distributed under a closed source licence but all the core libraries (for example libraries implementing X protocol compression), the modified X11 transport libraries (which implement proxying of any standard X client) and the NX agent (the program that runs X sessions on behalf of the user) are released under the GNU General Public Licence.

See our EULA for specific details: http://www.nomachine.com/licensing

NX Client can be distributed without modifications. NX Server cannot be distributed without prior permission from NoMachine. Companies who are interested in distributing the server software as part of their solution should contact us about joining the partner program.

Up to version NX 3.0.0, NX included modified versions of software from several other Open Source projects, such as X.Org, XFree86 and OpenSSH.

With the release of NX 3.0.0, users can see some changes to the third party software we include in our own packages. Please see the EULA linked above for further details.

When including Open Source software in our project we strictly followed the licensing terms of the original copyright holders (X, GPL, BSD, etc.). When a choice between multiple licensing terms was possible, NoMachine opted for the GPL licence.

Please also see our article about open source versions of NX Client.

https://www.nomachine.com/AR12B00110