NoMachine Terminal Server Node - Installation and Configuration Guide
Introduction
1. NoMachine Terminal Server Node Installation and Configuration Guide
Welcome to the NoMachine Terminal Server Node - Installation and Configuration Guide v. 7.
What is NoMachine Terminal Server Node for?
NoMachine Terminal Server Node is designed to be specifically installed on a Linux remote node and be part of a multi-node environment ruled by a NoMachine Enterprise Terminal Server.
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It is not a standalone server and cannot accept direct connections to its host!
Once installed, the NoMachine Terminal Server Node has to be added to the Enterprise Terminal Server.
Users will connect to the Enterprise Terminal Server which is the single point of access to all the available nodes. Depending on the Enterprise Terminal Server's configuration, users will be able to choose the node on which to run their virtual desktop and/or sessions will be automatically load-balanced among the nodes (default).
Setting-up a multinode environment made of a NoMachine Enterprise Terminal Server plus a scalable number of Terminal Server Nodes is a solution for centralizing access to multiple hosts and distributing the load among them.
A Graphical Interface
The NoMachine Terminal Server Node package includes a NoMachine UI for administering the node and its services (Server settings).
Most common operations detailed in this guide can be performed by the NoMachine UI and the Server settings panel running on the local installation of the Terminal Server Node.
The Terminal Server Node comes also with a client UI for running sessions and connecting to other remote desktops.
The Terminal Server Node is ready once installed
Installation provides a fully operative NoMachine node with a default configuration suitable for the majority of environments. All the necessary services are automatically started.
Just add it to the Enterprise Terminal Server!
A node of the Enterprise Terminal Server
NoMachine Terminal Server Node, available for Linux only, supports unlimited concurrent virtual desktops. A virtual desktop is an individual instance of the remote desktop. Sharing of a virtual desktop is also supported. The number of users is not limited.
1.1. About This Guide
Document Conventions and Important Notices
The following conventions are used in this guide:
BaseDirectory
is the base directory where the NoMachine binaries and libraries are installed.
By default, BaseDirectory is: /usr.
InstallationDirectory
is: BaseDirectory/NX, i.e. /usr/NX.
The command line interface
NoMachine server and node programs have a command line interface to execute operations.
You need to be a privileged system user to access all these functionalities. These commands can be run from an xterm or similar using the sudo utility or as root.
On Linux invoke the 'nxserver' and 'nxnode' programs from /etc/NX, for example:
$ sudo /etc/NX/nxserver --status
Printing the server and node usage doesn't require to be a privileged user, instead:
$ /etc/NX/nxserver --help
$ /etc/NX/nxnode --help
The 'nxserver --help' and 'nxnode --help' display the list of all the available commands and options and their description.
2. Install the Terminal Server Node
2.1. Prerequisites
Supported Operating Systems
Linux 32-bit and 64-bit
RHEL 4 to RHEL 8
SLED 10 to SLED 15
SLES 10 to SLES 15
openSUSE 10.x to openSUSE 15.x
Mandriva 2009 to Mandriva 2011
Fedora 10 to Fedora 31
Debian 4.0 to Debian 10
Ubuntu 8.04 to Ubuntu 20.04
Raspberry Pi 2/3/4 ARMv6/ARMv7/ARMv8
Hardware requirements
Intel Core2 Duo or AMD Athlon Dual-Core or equivalent
1 GB RAM
Network connection (either a LAN, or Internet link: broadband, cable, DSL, etc...)
Size required on disk:
Linux 115 MB
Software requirements
A desktop environment must already be installed. This applies also to headless Linux machines.
Web sessions and NoMachine client's sessions are supported. Users must connect to the Enterprise Terminal Server in order to run the session on the Terminal Server Node host (the node doesn't accept direct connections).
Even if it's advisable to upgrade client installations to the same version 7 of the of the Enterprise Terminal Server and Terminal Server Node, compatibility with clients v. 6 and 5 is preserved.
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It's strongly advisable to keep version of Enterprise Terminal Server and of its Terminal Server Nodes always aligned!
2.2. Linux Installations
Installing for the first time
You can install, update and uninstall using the graphical package manager of your Linux distribution or from command line by running commands from an xterm or similar with the sudo utility, or as root user if you don't have sudo installed. Instructions below refer to installation by command line.
Successive updates
The update procedure for server and node installations requires all NoMachine services to be stopped in order to correctly replace libraries and binaries. This implies that the Terminal Server Node is not accessible to users during the update procedure. Current sessions will be terminated, users will be able to connect again later.
There are two ways to update your current installation:
I Automatic updates
You can update your installation from our repositories. Just run the NoMachine UI from your Programs Menu and open the Server -> Settings -> Updates panel and click on 'Server preferences'. Go to the 'Updates' UI and click on the 'Check now' button.
NoMachine has the automatic check for updates enabled: it will check by default our repositories every two days to verify if updates are available. In this case, the server will prompt a dialog informing that a new version is available but it will never automatically update the current installation.
Checking for updates can be disabled from that dialog by selecting the 'Don't ask again for this version' option or in the Updates panel by unchecking the 'Automatically check for updates' option.
II Update with NoMachine packages
Alternatively, download the latest available package from the NoMachine web site and click on the executable file to launch Setup. As for the installation, Setup will guide you through all steps necessary for updating your installation.
2.3. RPM Packages
If you want to install to default location, namely /usr/NX/:
INSTALL
# rpm -ivh <pkgName>_<pkgVersion>_<arch>.rpm
To find out which NoMachine package you have installed (you will get the full name of the package), run:
# rpm -qa | grep nomachine
UPDATE
# rpm -Uvh <pkgName>_<pkgVersion>_<arch>.rpm
UNINSTALL
# rpm -e nomachine-terminal-server-node
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For non-default locations, for example /opt/NX:
INSTALL
# rpm -ivh <pkgName>_<pkgVersion>_<arch>.rpm --prefix /opt
UPDATE
# rpm -Uvh <pkgName>_<pkgVersion>_<arch>.rpm --prefix /opt
UNINSTALL
# rpm -e nomachine-terminal-server-node
2.4. DEB Packages
If you want to install to default location, namely /usr/NX/:
INSTALL
$ sudo dpkg -i <pkgName>_<pkgVersion>_<arch>.deb
To find out which NoMachine package you have installed (you will get the full name of the package), run:
$ dpkg -l | grep nomachine
UPDATE
$ sudo dpkg -i <pkgName>_<pkgVersion>_<arch>.deb
UNINSTALL
$ sudo dpkg -r nomachine-terminal-server-node
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For non-default locations, for example /opt/NX:
INSTALL
$ sudo NX_INSTALL_PREFIX=/opt dpkg -i <pkgName>_<pkgVersion>_<arch>.deb
UPDATE
$ sudo NX_INSTALL_PREFIX=/opt dpkg -i <pkgName>_<pkgVersion>_<arch>.deb
UNINSTALL
$ sudo dpkg -r nomachine-terminal-server-node
2.5. TAR.GZ Packages
If you want to install to default location, namely /usr/NX/, ensure that the package is placed there.
INSTALL
$ cd /usr
$ sudo tar xvzf <pkgName>_<pkgVersion>_<arch>.tar.gz
$ sudo /usr/NX/nxserver --install
UPDATE
$ cd /usr
$ sudo tar xvzf <pkgName>_<pkgVersion>_<arch>.tar.gz
$ sudo /usr/NX/nxserver --update
UNINSTALL
$ sudo /usr/NX/scripts/setup/nxserver --uninstall
$ sudo rm -rf /usr/NX
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For non-default locations, for example /opt/NX:
INSTALL
$ sudo NX_INSTALL_PREFIX=/opt /usr/NX/nxserver --install
UPDATE
$ sudo NX_INSTALL_PREFIX=/opt /usr/NX/nxserver --update
UNINSTALL
$ sudo /opt/NX/scripts/setup/nxserver --uninstall
$ sudo rm -rf /opt/NX
2.6. Activating the License (for Customers)
Customer packages
include a temporary (30-days) node.lic and server.lic files for evaluation.
Such license files have to be replaced with the customer's license files acquired from NoMachine.via the NoMachine UI in Settings -> Server -> Updates panel: click on 'Server subscription' and 'Node subscription' to read the current license file. Click on 'Replace' button to activate a new license file.
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Starting from version 7, the server will cease to work 60 days after the license expiration date. Please contact your NoMachine provider or the Support Team for renewal options.
To verify from command line that node.lic is correctly in place and check its validity, you may run:
$ sudo /etc/NX/nxnode --subscription
$ sudo /etc/NX/nxnode --version
3. Initiating a NoMachine Connection (end-user side)
Pre-requisite: you need to have a valid account on the Enterprise Terminal Server and on the Terminal Server Node(s), password cannot be empty. Your account can be a local account or a LDAP account or an AD account. NoMachine doesn't check if the source of users' account information is for example LDAP or local account database. Be sure to configure the login in advance.
3.1. Connecting by Browsers or NoMachine Client to the Enterprise Terminal Server
Once added to the Enterprise Terminal Server, the Terminal Server Node is ready to go.
To connect via web, the end-user should point the browser on his/her device to the name or IP address of the Enterprise Terminal Server host.
In a similar way, when connecting form a client device, the user will have to specify the IP or hostname of the Enterprise Terminal Server while creating the connection.
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I Auto-reconnection is supported: when the connection is lost for whatever reason (including when the client host has entered sleep mode), the client will automatically try to reconnect for as long as the user keeps the UI or the web page open. If reconnecting is not possible, then the user will have to reconnect manually.
II IPv6 is supported: specify the IP address of the server host in IPv6 format (e.g. 2001:0:5ef5:79fb:30c6:1516:3ca1:5695) if you want to use it instead of IPv4.
3.2. Load-Balancing vs. Manual Selection of the Node
By default, the NoMachine Enterprise Terminal Server makes available the Terminal Server Node for the automatic load-balancing of virtual desktops. This means that the server, based on its load-balancing algorithm, will select the node where the new virtual desktop will be started. The server can be also configured to let the user choose the node.
4. Compression Techniques and Optimizations
4.1. Video Stream Encoding in Web Sessions
In the case of web sessions, by default, session data is streamed in video frames compressed and decompressed by using the MJPEG lossy algorithm, which is the video-format widely supported by browsers.
Oher video codecs like VP8 and H.264, require a browser which supports WebRTC and HTML5.
NoMachine web sessions use the H.264 video streaming when the following requirements are all met, otherwise VP8 is used. In practice, when WebRTC is enabled, the H.264 or VP8 encoding will be used, otherwise MJPEG will be used:
I WebRTC is enabled.
II The browser supports WebRTC and the H.264 decoding
In practice, when WebRTC is enabled, the H.264 or VP8 encoding will be used (if the browser supports WebRTC), otherwise the classic web media exchange protocol will be used and MJPEG will be the codec.
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H.264 hardware encoding is possible when the Terminal Server host machine has an hardware accelerated video cards (GPU) with Nvidia Kepler microarchitecture onward or Intel Quick Sync processors or AMD card (at the moment only on Windows).
Optimizations
Optimizations can be done in two ways: (I) by adjusting display settings in the session or (II) by enabling WebRTC.
I Adjusting display settings in the web sessions
To access NoMachine display settings, open the NoMachine menu inside the web session: press ctrl+alt+0 or click on the page peel in the upper right corner of the window to open it. Then click on the 'Display' button and finally on 'Display settings'. From this panel you can do the following.
Change the display image quality
Increasing the quality will mean to apply a minor compression ratio, the image will be clearer, but more bandwidth will be used.
Disable network-adaptive display quality
This will anchor the display quality to the fixed value specified in the Display quality slider, making it independent from the current network congestion. This is not recommended when there is a very limited bandwidth.
Disable multi-pass display encoding
Default settings within the encoding will work to refine the image progressively to the target quality (as specified in the Display quality slider) starting from a lower quality version of the image during moments of inactivity of the desktop. Disabling this refinement sends the image directly with target quality. Not recommended when there is limited bandwidth.
II Enabling WebRTC on Enterprise Terminal Server
NoMachine web sessions use by default the classic web media exchange protocol for the two-way browser/web server communication. WebRTC (Real-Time Web Communication) is also supported and can be enabled as explained in the next paragraph.
Enabling WebRTC allows to use the H.264 video streaming (when possible) or VP8 which optimize the user experience with multimedia applications and contents.
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You may verify which encoding method is in use from the NoMachine menu inside the session: press ctrl+alt+0 or click on the page peel in the upper right corner of the window to open it. Then click on the 'Display' button and finally on 'Display settings'. The codec actually in use is reported at the bottom left of the menu.
4.2. Video Streaming Encoding in Client Sessions
Sessions run by NoMachine client use a combination of video and image encoding based on standard codecs and a number of techniques developed by NoMachine. Frames are encoded into a video stream optimized by means of a compression and decompression algorithm of real-time image and audio data. VP8, H.264 and MJPEG encoding are supported.
In general VP8 and H.264 are suitable for all situations, while MJPEG can be an alternative when the end-user's computer is less powerful and the user is experiencing slow responsiveness.
The display encoder can be changed on the server:
from theUI
In the Settings ->> Server -> Performance panel.
or in the node configuration file
Enable the use of a specific codec by editing the node configuration file and enabling the following two keys:
EnableDisplayServerVideoCodec 1
DisplayServerVideoCodec CODEC
where CODEC can be: 'vp8','h264' or 'mjpeg'. For example:
EnableDisplayServerVideoCodec 1
DisplayServerVideoCodec mjpeg
4.3. The X11 Vector Graphics Mode in Client Sessions
The X11 vector graphics mode is enabled by default for (i) virtual desktops and (ii) custom sessions in floating window mode. This mode is mainly a set of NoMachine techniques to compress and optimize the X11 protocol (by applying the same alghoritms available with the NX compression protocol v. 3). These compression techniques are applied to all non-video contents like textual elements, while multimedia content is encoded in a video stream (VP8 or H.264).
The X11 vector graphics mode is useful for avoiding loss of image quality and in general is the best option when working with traditional UIs or a large amount of text. However it's not advisable for multimedia content or applications with many graphical effects.
This mode can also help to reduce bandwidth usage, decrease the HW requirements on client and server (expensive video encoding/decoding operations are applied only to multimedia contents), increase responsiveness on slow link and end-users' clients without hardware accelerated video encoding/decoding capabilities.
You can disable/enable the X11 vector graphics mode
via the UI
In the Settings ->> Server -> Performance panel.
or in the node configuration file
for disabling the X11 vector graphics mode, edit the node configuration file, uncomment and set:
AgentX11VectorGraphics 0
or to enable it:
AgentX11VectorGraphics 1
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I In the case of slow bandwidth, decreasing the quality level of images could help but if you need to have a perfect image without quality loss, you have to increase the display quality instead. It's also suggested to disable multi-pass encoding to avoid the 'out of focus' effect: multi-pass is an encoding technique which uses multiple passes to reach progressively the best definition of the image.
II Quality level and multi-pass encoding can be tuned from the NoMachine menu inside the session in the Display -> Change settings panel. (Ctrl+alt+0 or click on the right upper corner of the window to open the NoMachine menu).
4.4. Supporting OpenGL Applications in Virtual Session
In NoMachine virtual desktops and custom sessions, OpenGL rendering is done by default by software components. This means that rendering tasks are accomplished by CPU and not offloaded onto GPU. Such operations could be resource-demanding, especially in the case of 3D desktop graphics effects, and make the user interface look slow.
A possible alternative is to configure the NoMachine server to use the VirtualGL libraries (included in the NoMachine package) and therefore activate support for HW accelerated OpenGL applications. This allows OpenGL applications, namely 3D applications, to use server side graphics hardware.
5. Terminal Server Node Configuration
5.1. Configuration Files
The configuration file for the Terminal Server Node is mainly node.cfg. In some cases it may be necessary to adjust some settings also in the server configuration file, server.cfg. In effect, the Terminal Server Node package includes the nxserver program as well, which still manages users and sessions on localhost but doesn't accept connections unless they come from the Enterprise Terminal Server.
Configuration files are placed in the BaseDirectory/NX/etc directory:
/usr/NX/etc/server.cfg
/usr/NX/etc/node.cfg
The Default Configuration
NoMachine Terminal Server Node comes with a default configuration that is sufficient to grant a working setup in the majority of environments. NoMachine administrators can tune their installation at any moment and according to their specific needs by setting the related configuration keys. In some cases this will require to restart all NoMachine services.
Edit the Configuration Files
NoMachine configuration files are text files made up of a number of key-value pairs. All the configuration files can be edited manually by a text editor, e.g. 'vi'.
Be sure to uncomment the configuration key (i.e., remove the '#' pre-pended to the key) to set a value different from the default.
When a configuration key supports an on/off status, set value to '0' to disable it and to '1' to enable it.
Make Changes to the Default Configuration Effective
Changes will be effective with the next new connection without the need to restart services if not otherwise specified.
5.2. Local and Network Ports
For each session, NoMachine uses ports that are used only locally on the node host and network ports.
Some ports are mandatory and must be free, e.g. the session display number and the connection port. Other ports are used for services that can be disabled, e.g. USB forwarding.
Local port Description How to change the default
11000 + DisplayBase Session display. If this port is already in use, NoMachine will look for a free port by incrementing DisplayBase up to the value set in the DisplayLimit server configuration key. DisplayBase (by default 1001) and DisplayLimit (200) are defined in server.cfg
20000 Communication port between the session's nxserver process and the main server process. Add the ServerSlaveBase key to the end of server.cfg and specify a value
24000 + DisplayBase Session's monitor port. DisplayBase (by default 1001) and DisplayLimit (200) are defined in server.cfg
5473 and 5483 USB devices forwarding. Disable USB sharing by setting EnableUSBSharing none in node.cfg
Network port Description How to change the default
6000 + DisplayBase TCP port for the NoMachine display service. If this port is already in use, NoMachine will look for a free port by incrementing DisplayBase up to the value set in the DisplayLimit server configuration key. DisplayBase (by default 1001) and DisplayLimit (200) are defined in server.cfg.
4000 TCP port for the NoMachine Network service (nxd) and connections via NX protocol. This port must be open in the firewall and mapped to the external IP of the server host. Set NXPort in server.cfg and restart the nxd service.
4011 - 4999 UDP port range. Set UDPPort in server.cfg to define a different range. UDP can be disabled on client side. Note that UDP is not used if the node is behind a firewall.
22 TCP port for connections via SSH protocol. This port must be open in the firewall and mapped to the external IP of the server host. Set a different port for the system SSH server and align value set for SSHDPort in server.cfg. Then restart the NoMachine server.
4080 and 4443 HTTP and HTTPS port for web connections. These ports must be open in the firewall and mapped to the external IP of the server host. Change 'Listen' directives in htd.cfg and restart the nxhtd service.
20000 - 30000 External ports range for UPnP port mapping. Set NXUPnPPort in server.cfg to define a different range. Set EnableUPnP none in server.cfg to disable port mapping.
5040 + x Port opened between client and server for each USB device. Port number is defined by 5040 + x where 'x' is the first free port retrieved starting from port number 5040. N/A
4000 Automatic updates from NoMachine repositories. Updates are managed by nxd. Disable automatic updates by setting UpdateFrequency 0 in server.cfg.
5473 and 5483 USB devices forwarding. Disable USB sharing by setting EnableUSBSharing none in node.cfg.
5.3. Hiding the NoMachine Monitor and Notification Messages
It is possible to hide or show the !M (the Monitor) icon in the system tray. When the icon is hidden, notification messages will still be displayed when users are connecting. This can be configured
from the UI:
In the Settings -> Server -> Security panel by selecting 'Hide the NoMachine icon in the system tray'. When the icon is hidden, notification messages will still be displayed when users are connecting.
or in the node configuration file
This setting is ruled by the DisplayMonitorIcon key in the node configuration file. If you change them manually by editing the file, you then need to restart the server to make changes effective.
To hide the !M in the system tray set:
DisplayMonitorIcon 0
To display the !M in the system tray set:
DisplayMonitorIcon 1
In both cases, then restart the server:
nxserver --restart
By default NoMachine issues a balloon message to notify about events like user's disconnection or user's requests for connecting. You can disable notification messages by setting the following key in the node configuration:
DisplayMonitorNotifications 0
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If the displaying of monitor's notification messages is disabled, the desktop owner will be unable to accept connection's requests by other users. Configure trusted users on the Enterprise Terminal Server if you need to allow connections without explicit authorization.
5.4. Hiding the Whiteboard and Chat Tools
If you want to disable the launching of the Whiteboard from the Monitor menu, edit the node configuration file to have:
EnableWhiteboard 0
Then restart the server:
nxserver --restart
6. Users Management
6.1. Managing Users on the Terminal Server Node Host
You can manage create and delete user accounts by using tools provided by your Operating System or the NoMachine server commands as explained below. Note that the user who will connect by NoMachine must have an account also on the Enterprise Terminal Server (username must be the same, password can be different).
Creating Accounts
nxserver --useradd USERNAME --system
Modifying the User's Password:
nxserver --passwd USERNAME --system
Listing the NoMachine Users:
nxserver --userlist
Removing Accounts:
nxserver --userdel USERNAME --system
6.2. Greeting Messages (for Virtual Desktops)
It is possible to welcome users when session is started by issuing a greeting message, either only the first time the user logs in or every time the user connects to the Terminal Server Node. Update the node configuration file by writing the text of your message in any of the following keys:
NodeFirstLoginGreeting "Welcome to your first NoMachine session"
NodeLoginGreeting "Welcome to your NoMachine session"
6.3. Notifications to Users
NoMachine provides an instant messaging tool, named whiteboard which allows also drawing and sharing files with connected users and fast-track access to file transfer. To access it, connect to the user's desktop and from the Monitor (!M icon) in your system tray click on 'Show the whiteboard'. Note that if multiple users are connected at the same time to the same session, they will all see the message.
As an alternative, it's possible to issue a dialog in the connected sessions to show a custom message by sending it from command line.
Sending a message to all running sessions:
nxserver --broadcast "Your message goes here"
or sending a message only to the session specified by its session id:
nxserver --message "Your message goes here"
7. Supported Server-Node Connection Protocols
Client connections are tunneled from the Enterprise Terminal Server to the Terminal Server Node. Server-node connections use by default the NX protocol for secure communication over the network. NX Protocol (default listen port 4000)
Encryption in the NX protocol is implemented using OpenSSL TLS/SSL, based on ECDHE-RSA-AES128-GCM-SHA256 as the default cipher suite. ECDHE-RSA-AES128-GCM-SHA256 is an AES (Advanced Encryption Standard) block cipher with 128 bits key in GCM (Galois/Counter Mode).
The
SSH Protocol (default listen port 4000)
As an alternative, it's possible to tunnel server-node connections using SSH.
The protocol, as well as the port if different from the default one, has to be defined while the Terminal Server Node is added on the Enterprise Terminal Server.
8. Sessions' Management
Each session is uniquely identified by a session id (which can look like: B253864E822F5A235825F3AB8853AF00) and a display id (e.g.,1002).
A session on the NoMachine Terminal Server Node can be in any of the following statuses:
Connected - when it's connected to the remote display.
Disconnected - this status is available only for virtual desktop sessions and custom sessions. A session is marked as disconnected when it's disconnected from the remote display. A disconnected session can be reconnected at any time even from a different machine (migration). While a session is disconnected, applications on the remote server stay running.
Finished - the session has been closed in a clean way and all NoMachine processes have been shut-down smoothly.
Failed - any of the NoMachine processes has failed to start or it has been "un-cleanly" terminated.
Transitional statuses are Connecting, Disconnecting and Terminating.
Sessions on the Terminal Server Node can be monitored and managed on the Enterprise Terminal Server.
8.1. Setting a Virtual Desktop Environment on Linux
Pre-requisite to connect by NoMachine is that a desktop environment is installed on the system even if the host is headless or not started in graphics mode.
By default when the user chooses to create a new virtual desktop, NoMachine runs the default X session set on the system.
During its installation, NoMachine detects the default desktop environment set on the system and configures the node accordingly. Path and command to start the system desktop environment is defined in node.cfg by the DefaultDesktopCommand key. The Workstation is able to detect GNOME, Unity, KDE, LXDE and Xfce. If you have a different desktop environment, you can edit the DefaultDesktopCommand key accordingly.
For example to run MATE:
DefaultDesktopCommand "/usr/bin/mate-session"
or to run Pantheon:
DefaultDesktopCommand "/usr/bin/gnome-session --session=pantheon"
If there are multiple desktop environments installed, you can configure NoMachine to provide users the list of all the available desktops. To do that, set xsessions=1 in the ConnectPolicy key in the server configuration (server.cfg). By default this is disabled (xsession=0). To enable it, set:
ConnectPolicy autocreate=1,autoconnect=1,automigrate=1,desktop=0,dialog=0,xsessions=1,udp=1
If there are GNOME and KDE installed, and/or if you want to provide XDM desktops, you can set desktop=1 in the ConnectPolicy key above.
To run GNOME and/or KDE, specify the command in the corresponding keys in node.cfg, for example
CommandStartGnome "/etc/X11/Xsession 'gnome-session --session=gnome'"
CommandStartKDE "/etc/X11/Xsession startkde"
8.2. Executing Custom Scripts on Node Events
The node configuration (node.cfg) provides a number of keys that can be activated to execute a custom script upon a certain event.
In a similar way, also the server configuration (server.cfg) gives the possibility to execute customer scripts. In case of Terminal Server Node however, only scripts related to login events can be set in server.cfg. Scripts related to session events have to be set in the node.cfg file.
A number of parameters can be specified for each script. Scripts set on the Terminal Server Node are executed on that host and apply only to those users who are connecting to it.
Available for Configuration key Accepted parameter (server.cfg) Accepted parameter (node.cfg)
server UserScriptBeforeLogin remote ip -
server UserScriptAfterLogin username,remote ip -
server UserScriptAfterLogout (available since v. 6.6.8) username, remote ip -
node UserScriptBeforeSessionStart session id, username, node host, node port, main session id(*), main session type(*) session id, username, session type, display, main session id(*), main session type(*)
node UserScriptAfterSessionStart session id, username, node host, node port, main session id(*), main session type(*) session id, username, session type, display, main session id(*), main session type(*)
node UserScriptBeforeSessionDisconnect session id, username, node host, node port session id, username, session type, display
node UserScriptAfterSessionDisconnect session id, username, node host, node port session id, username, session type, display
node UserScriptBeforeSessionClose session id, username, node host, node port, main session id(*), main session type(*) session id, username, session type, display, main session id(*), main session type(*)
node UserScriptAfterSessionClose session id, username, node host, node port, main session id(*), main session type(*) session id, username, session type, display, main session id(*), main session type(*)
node UserScriptBeforeSessionReconnect session id, username, node host, node port session id, username, session type, display
node UserScriptAfterSessionReconnect session id, username, node host, node port ssession id, username, session type, display
node UserScriptAfterSessionFailure session id, username, node host, node port,main session id(*), main session type(*) session id, username, session type, display, main session id(*), main session type(*)
(*) 'main session id' and 'main session type' parameters are available only when the user connects to an already running virtual desktop (session shadowing). They indicate respectively the id and type of the session to which the user is connected with his/her own session qualified by 'session id' and 'session type'.
A further key in the node configuration file, allows to run a custom script triggered on change resolution events (resize of the remote screen). The related key is:
UserScriptAfterRemoteResize
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the order of parameters is relevant. For example, a custom script to be run on node event 'UserScriptBeforeSessionStart' should use the $2 variable to retrieve username and $4 to retrieve display.
Pre-requisites to run custom scripts
Custom scripts must be executable. Custom scripts set-up in server.cfg are executed by the nxserver program. Since nxserver is running as the nx user, you have to grant this user the necessary permissions in order to execute the custom script.
Custom scripts set-up in node.cfg are executed by the nxnode program, which is run as the connected user. Place the script in a directory that is accessible by the node, i.e. accessible by the connected user(s).
By default if the execution of the scripts fails, the nxserver and nxnode will terminate. This means that the user's session will not start. You can override this behavior by forcing exit 0 inside the custom script and let the session start even if the custom script is failed.
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If custom scripts triggered on login events have to be applied to all users connecting to the multi-node system, they have to be placed in the server.cfg file of the Enterprise Terminal Server.
8.3. Limiting or Terminating Virtual Desktops Automatically
In order to limit the number of virtual desktops on this Terminal Server Node, it's advisable to use profile rules. They have to be executed on the Enterprise Terminal Server.
As an alternative to profile rules, the server.cfg file on the Terminal Server Node provide the following keys:
VirtualDesktopsLimit 20
VirtualDesktopsUserLimit 20
ConnectionsLimit 20 ConnectionsUserLimit 20
which respectively limit by default to 20 the maximum number of: concurrent virtual destkops, users who can run a virtual desktop, connections (virtual desktops + sharing of virtual desktops + connections to physical desktop if any) and users (who run virtual desktops + connect to a virtual desktops + special users who can connect to the physical desktop of the Terminal Server Node host).
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To limit the maximum number of concurrent virtual desktops on this node for example to 60:
Increase the value set for the virtual desktop limit in the server.cfg of the Terminal Server Node to for example 100:
VirtualDesktopsLimit 100
or set it unlimited:
VirtualDesktopsLimit 100
Then execute on the Enterprise Terminal Server host the following command. NODE:PORT is the name of the Terminal Server Node, as it appears in the ouput of 'nxserver --nodelist' executed on the Enterprise Terminal Server:
nxserver --ruleadd --class node --type virtual-desktops-limit --value 60 --node NODE:PORT
Disconnecting or Terminating Virtual Desktops Automatically
To disconnect a virtual desktop or custom sessions after a certain time of inactivity, uncomment and set a proper timeout value, in seconds, in the following node configuration key. For example, if you want to terminate sessions after 10 minutes of inactivity you need to set:
DisplayServerExtraOptions "-timeout 600"
If the NoMachine display agent doesn't receive any input from the user in the given timeout, it will either disconnect or terminate the session. Termination of the session will be carried out if the session is not persistent or no X application is connected to the display. Otherwise the agent will disconnect the session so that the X applications will be left running.
Note that the DisplayServerExtraOptions key is only for virtual desktops or custom sessions with X11 vector graphics enabled (default).
For sessions connected to a virtual desktop (sharing of the virtual desktop), virtual desktops with X11 vector graphics disabled and connections to the physical desktop set instead:
DisplayAgentExtraOptions "-timeout 600"
9. Device Sharing, Copy&Paste and File Transfer
The Terminal Server Node allows users to access and share their devices and resources from local to remote and vice-versa. Disks, printers, USB devices and more can be connected inside the session to easily access them from both client and server side. At present device sharing is not available with web sessions and is only available in connections by NoMachine client.
Two-way copy and paste is fully supported. Web sessions implement the NoMachine virtual clipboard which allows copying text from/to the session running in the browser and the local computer.
Download/upload files from the session to the local computer and vice-versa is also fully supported in client and web sessions, as well as drag and drop of a file from remote to local and from local to remote.
By default device sharing, copy&paste and file transfer are always permitted. You can however completely disable any of these services or disable it only partially, for example to prevent users from sharing their local printer in the NoMachine session but permitting them to use the remote printer.
Limiting or forbidding device sharing, copy and paste and file transfer can be done on the Enteprise Terminal Server by means of profile rules.
10. Multimedia and Session Recording
10.1. Supporting Audio and Microphone
On Linux, NoMachine audio framework is integrated with PulseAudio sound server. If PulseAudio is not available on the system, NoMachine is able to use ALSA (Advanced Linux Sound Architecture). This is automatically managed by the NoMachine server so that multimedia support can work out of the box without the need for any configuration. If both PulseAudio and Alsa are available, the administrator might want to configure the node to use one or the other.
Disabling or Setting Audio Support
To disable audio and microphone support, uncomment and set the AudioInterface key to 'disabled' in the node configuration file:
AudioInterface disabled
On Linux it is possible to define whether PulseAudio Server or ALSA has to be used by setting AudioInterface key to 'pulseaudio' or 'alsa' respectively. For example:
AudioInterface pulseaudio
10.2. Recording your Screen
NoMachine can record in a video all activity made inside the session or on the desktop. To start the recording of the session, users should open the NoMachine menu inside the session (ctrl+alt+0) and click on the 'Recording' button icon to access the Recording panel. From this panel it's possible to open the recording bar, change audio and video quality and open the recording directory to access all recorded files. Session recording is not available with sessions on the web.
To record activity made on the desktop, start the recording from the !M icon menu in the system tray of the Terminal Server Node host and show the Recording bar from there. Desktop activities can also be registered on the physical desktop without the need to be connected via NoMachine.
Recorded files are saved by default in WebM format and can be played back directly with NoMachine or any other player supporting that format. Video streams can be encoded only with VP8 or H.264 when supported. Recorded files are saved by default on the user's device in the NoMachine directory under the 'Documents' directory.
Disabling session recording
To prevent users from recording their session activities, edit the node configuration to set:
EnableSessionRecording 0
Disabling desktop recording
To prevent users from recording desktop activities, even when physically logged into the Terminal Server Node host, edit the node configuration to set:
EnableLocalRecording 0
10.3. Automatic Screen Recording
The automatic recording of the session at session startup is disabled by default.
To enable it, execute in a terminal:
sudo /etc/NX/nxserver --recording yes
The automatic screen recording applies to both sessions connections to the physical display and virtual desktops.
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You can also define the percentage of session to be recorded by specifying the '--percentage PERCENTAGE' parameter or activate the recording for a specific user only or group of users by means respectively of: '--user ' and '--group '.
11. Automatic Updates
The Terminal Server Node, as well as the other NoMachine client and server products, periodically checks NoMachine repositories (by default every two days) to verify if updates are available and will prompt a dialog informing the user that a new version is available.
It will never automatically update the current installation. Also the download in background of a new software version will not lead to an automatic update of the current installation.
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