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Searching in: Articles & FAQs
ID: AR05F00510
Applies to: NX Licensing
Added on: 2008-05-26
Last update: 2015-05-27
Concurrent sessions and user names explained for NX 3.5.0

This article applies to NX server products version 3.5.0. For upgrading from v. 3.5.0 to version 4 and choose the right product, please read here:

Concurrent connections or sessions, whatever the product, indicates the maximum number of running, shadowed and disconnecte dsessions that NX Server can allow.

'Users' indicates the maximum number of user names that NX Server will administer.

NX Free Edition
With NX Free Edition, only 2 concurrent connections at any one time will be allowed, and up to 2 user names is permitted. Let's take an example, NX Free Edition (FE). If, on one particular server where you have installed NX FE, User A logs in, suspends their session, and starts a new session, they have thus reached the maximum number of concurrent sessions permitted on that server. So User B, although a legitimate user, will not be able to run a session.

NX Enterprise Desktop
NX Enterprise Desktop will allow 2 concurrent sessions but unlimited user names. This does not mean that it will allow all of its users to have 2 sessions. That would mean permitting a large number of concurrent sessions, something which is offered by the NX Enterprise Server.

E.g., "A third user can't log on. I am using NX Enterprise Desktop."
User A logs in (one session), User B shadows User A's session (2nd session) and then User C can't log on. This is because your main session and the shadow session mean that the maximum of 2 sessions has been reached. So User C, although a legitimate user, will not be able to run a session.

NX Small Business Server
This product  (NX SBS) allows up to 10 concurrent sessions, and 10 user names. The same rules of NX ED apply: if each of the 10 users has one running or suspended session, this will be counted as 10 concurrent sessions, so no other sessions will be allowed. NX SBS will split its maximum of 10 sessions among the named users. If one user disconnects or terminates a session, another session will be allowed but only from one of the already known users.

If you want to add a new user name and you have already reached the maximum of 10 names, you will need to remove one of those 10 users to allow for the creation of a new user.

NX Enterprise Server and NX Advanced Server
These 2 products allow an unlimited number of connections and user names, so there should not be any issues with getting users to connect or adding users. Make sure that the appropriate configuration keys are set in the server cfg to ensure unlimited connections are allowed.

How can a user have more than one concurrent remote session window open?

The reconnection policies currently in place mean that if a user has a remote
NX session running, and attempts to run a second session, the user will be connected automatically to the first window.

In order to have multi remote sessions open at the same time and of the same session configuration, the user will have to alter the session name. For example, with NX Enterprise Sever, this will result in User A being able to run sessions 1, 2, 3, 4 etc with session names "session1", "session2", "session 3" and so on.

How do limits on number of concurrent sessions work?

  • The maximum number of concurrent sessions depends on both the NX Server subscription and the value set in the SessionLimit key in the server.cfg file. If the server allows unlimited concurrent connections, it is possible to increase the default limit (which is 20) by editing the server configuration file as explained at:

    If the subscription allows instead a limited number of concurrent connections, this limit overrides the value set for the SessionLimit key in the server.cfg file. This is valid for NX evaluation servers, too.

  • Sessions in disconnected state and shadowing sessions count to the number of concurrent connections because they are all running sessions. To check the running sessions, consult Section 10 of the Admin Guide:
  • When the concurrent connections limit is reached, and the user tries to open a new session, NX Client will prompt the user with the available session window but the "New" button is greyed out.
  • When the concurrent connections limit is reached, and the user tries to shadow a session, the user will receive this error in the details popup issued by NX Client:

    NX>  599 Reached the maximum number of concurrent sessions on this server

    The same error can be found in the system log.