Well, when you order a license of NX, i think that you must have a network adapter to lock the license against. I don't think that one can lock the license against a "dongle" anymore.
- You will need to provide Siemens a "Composite Host ID" which is a mixture of your network address and some other hardware component identities. ( supposed to be a unique ID for the respective computer.)
When the license server ( the license service) is installed, the network adapter needs to respond to the licence service but you need no network out from the computer. - I think that the adapter therefore must be running.
The license service and NX checks each other "now and then" in so called heartbeats , NX allows a number of lost heartbeats without problems. For example i regularly move my laptop , with a NX session up, without network connection, from my desk to some conference room. Siemens does not say how often these heartbeats occur or how many lost heartbeats if tolerates. That would bee too easy for a potential hacker.
I think that i thereby answered also your second question.
When you buy NX, you either buy with or without maintenance ( there might be other options as well)
with maintenance you pay a monthly fee, you can report problems, get help from GTAC, download updates and new versions of NX.
Without i think you can download updates to the "Bought" release" but there is no help from GTAC nor new versions.
Regards,
Tomas