Here you can find the answers to some of the common questions about NoMachine software.
Please be sure you also visit the NoMachine Support Center for a complete source of articles & other documentation available in the
NoMachine Knowledge Base.
NoMachine is free to download and install for anyone who wants a remote desktop software for personal, or individual, use. I.e if you are looking for a remote access software to install on your home/office/school PC or Mac in order to access its files and documents, play games, view or upload multimedia, carry out some remote admin work etc, you can install the free NoMachine package.
On the connecting device, install the right package for your operating system (clients are available for Windows, Linux, Raspberry, Mac, iOS and Android). Please note that iOS and Android packages are available to download from their respective stores.
If you need to access your office computer, and provided it's not to carry out activities which would be considered "commercial usage" as per the EULA (https://www.nomachine.com/licensing), you can also install the free version.
What is considered private or individual use? The list can be endless, but some typical scenarios are:
- Accessing your computer (at home or the office) to work on and view your own personal files.
- Sharing your desktop with a friend or colleague.
- Accessing your family's or friend's computer to help them out.
- Sporadic remote admininstration of a computer at work.
So, what is considered commercial use?
A commercial user is defined as "an individual or entity, or an individual acting on behalf of an entity, who uses the Software or causes the Software to be used within or to provide commercial products or services to third parties."
Remember that on the connecting device, clients are free, so choose from NoMachine or Enterprise Client. On the host or computer you want to access, one of the NoMachine for the Enterprise products will be required. In our specific example, the alternative to the free NoMachine software package is Enterprise Desktop.
Some typical commercial scenarios:
- Offering access to a hosted desktop as part of your company's services for employees or customers.
- Reselling NoMachine software as part of a business-related service offering.
- Accessing multiple computers to carry out regular business-related activity for your organization.
Subscriptions to Enterprise Desktop are available for purchase to anyone who wants the benefit of technical assistance and unlimited connections on the remote desktop being accessed. See the following article for more details: https://www.nomachine.com/AR07L00808.
When you access the physical desktop remotely, you are connecting to its physical display. This functionality is provided by both the free to download NoMachine for Win/Mac/Linux and Raspberry packages, and the NoMachine Enterprise Desktop product.
On Linux, when connecting to the physical desktop which doesn't have an X server running (e.g. it's a headless machine), NoMachine is able to use its own display service (that is an embedded X server) to let users connect seamlessly to a physical desktop running in the background on the remote machine. Pre-requisite is having a desktop environment installed. This ability is enabled by default in NoMachine free version, but can be activated also for the other server types. See: https://www.nomachine.com/FR10L02842 for more details.
If multiple users are supported and they connect, they will all see the same desktop. However, if you run Linux, by installing any of the products from the NoMachine for Enterprise Terminal Server range, instead, you can run "virtual desktop sessions". The virtual desktop functionality allows individual multiple Linux desktops to run on the same host. Each user can have their own personal 'virtual' Linux desktop according to how the Administrator has configured it.
The virtual desktop functionality is not available on Windows or Mac.
You can run a 'virtual desktop' session, provided you have one of the following installed on a remote Linux host: Workstation, Small Business Server, Terminal Server, or Enterprise Terminal Server. Use either NoMachine or Enterprise Client to connect. As long as the virtual desktop functionality is enabled, the connection GUI will allow you to run a virtual desktop, or alternatively a 'Custom session' (virtual single applications on Linux). Connections by the web are also supported.
Depending on the type of server product installed, you will be able to run from 4 virtual desktops to an unlimited number. User numbers are unlimited in that you can have as many user name accounts as needed. It is the number of concurrent virtual desktops which is considered. For example, in the case of Workstation, only 4 virtual desktops will be allowed at any given time; with Small Business Server that number is 10, and with the Terminal/Enterprise Terminal Servers that number is unlimited.
NoMachine for Mac, Windows or Linux lets you connect to your own desktop remotely to grab forgotten documents, watch one of your videos stored on it, or play your favorite game. One connection is permitted with the free version to let you get access to the physical desktop of the remote computer. It can also be installed on a virtual machine running one of the supported platforms.
Alternatively, you can let a friend connect to your desktop when you're working on it. It’s as if you’re sitting down in front of a computer together with them. You will both see the same desktop. Your friend can troubleshoot your computer, or you can help them. You can collaborate on a document together, watch a film, swap files, whatever you want.
To access your remote desktop using NoMachine, you will need to have a user account on the remote computer you want to connect to. See our online tutorial to get started:
NoMachine's commitment has always been to provide packages for the widest range of most frequently used platforms and operating systems. NoMachine software runs on Mac OS X, Windows and Linux operating systems, the minimum required versions are:
Mac OS X 10.7
Red Hat Enterprise 4.4
Open SUSE 10.x
Debian GNU Linux 4.0 Etch
Ubuntu 8.04 Hardy Heron
Raspberry Pi 2/3 ARMv6/ARMv7/ARMv8 (for which a selection of distributions is supported. Please consult the dedicated article for Raspberry here: https://www.nomachine.com/AR07N00896
For a complete list of platforms supported by the current version of NoMachine products, please also refer to the download page of each product.
Rest assured that the NoMachine development team will continue to work hard to add support for further environments and/or processor architectures in the future; and will take into account the latest versions of the supported operating systems as per support policies already in place.
In general NoMachine should work with the latest version of the Operating System, unless major changes in the OS require NoMachine to align its own software. In that case, a period of at least 30 days is generally required to ensure full compatibility. You might also be interested at NoMachine policies to support pre-release versions of operating systems:
Regarding earlier versions of Operating Systems, in order to ensure a consistently high quality remote access software across the most popular platforms, as well as because of some technical considerations related to the evolution of NX software, the following OS versions are no longer supported since NoMachine v. 4:
The NoMachine free package, tailored for personal use, never expires. By installing it on the host you want to access, you are allowed one connection to the desktop running there.
Enterprise Desktop, installed on the remote computer you want to access, offers unlimited connections to the remote physical desktop. Multiple users connecting, who must have an account on the remote host, will be able to simultaneously view and interact with the same physical desktop. In addition to the features available in NoMachine, users get:
- simultaneous connections to the desktop
- browser-based access
- connections over SSH
and purchasing an annual subscription also gives you access to technical assistance via the customer area. Enterprise Desktop has a starting price of $44.50.
What the two packages have in common is that they both include the connection user interface (NoMachine player) which lets you connect to another host with NoMachine server-side software installed. If users prefer to install just the NoMachine player component, so remote access to that computer won't be possible, Enterprise Client can be installed instead.
All NoMachine products support GPU-accelerated encoding and decoding, and from version 6.6.8 all products provide H.264 software acceleration capabilities.
NoMachine always prefers to use hardware encoding to produce the contents of the screen, using the GPU and the tools and methods it makes available. However, there are cases in which the GPU does not provide these tools or hardware encoding is not available.
When the server or client doesn't have the necessary hardware requirements to use GPU-based acceleration, H.264 software acceleration can be used. In these cases, NoMachine "falls back" to software encoding, which is slower and does not allow us to offer the same level of interactivity. Similarly on the client, where a hardware decoder is not available, software decoding is used.
In versions prior to 6.6.8, the software encoder and decoder used were based on the VP8 standard, unless the user had purchased the additional AVC Pack which includes the libraries, protected by an international patent by the MPEG LA consortium, and which therefore require a license fee. The Enterprise server products have always shipped the H.264 software encoder as part of its functionality.
With the release of version 6.6.8, NoMachine decided to include these libraries in all free products, covering the costs of the user license fees at its own expense and thus offering the best performance offered by the AVC/H.264 video encoding standard. When the GPU or HW system in use does not offer an H.264 hardware encoder or decoder, H.264 software encoding will be used.
This decision effectively eliminates the need for the AVC Pack and the open-source libraries, making H.264-enabled video encoding completely seamless for users and guaranteeing a video streaming experience with unparalleled quality.
All packages for Windows, Linux, Mac and Raspberry include the AVC/H.264 software codec. When the hardware encoding or decoding is not available, NoMachine falls back to software encoding/decoding. No further actions are necessary to enable H.264 support in NoMachine sessions.
For web sessions (from v. 6), H.264 is used when the browser supports WebRTC/HTML5 and H.264 and the support for WebRTC is enabled on the NoMachine Server.
NoMachine and H.264 hardware acceleration (GPU)
NoMachine supports H.264 hardware acceleration for these types of sessions:
(i) Connections to the remote physical desktop.
(ii) Linux virtual desktops without activating X11 vector graphics mode.
H.264 HW acceleration will be soon available also for virtual desktops in X11 vector graphics mode (https://www.nomachine.com/FR11O03550). H.264 HW acceleration will also be applied to multimedia content in custom sessions.
GPU encoding (server side)
NoMachine supports H.264 hardware encoding provided by graphics cards (GPUs) with Nvidia Kepler microarchitecture onward.
From v. 6, also Intel Quick Sync video cards on Windows and Linux are supported. On Linux, it's necessary to apply a manual configuration as explained here: https://www.nomachine.com/AR09O00938.
GPU decoding (client side)
NoMachine software on the user's computer (i.e. NoMachine used as a client or Enterprise Client) supports the H.264 hardware decoding on Windows and Mac hosts with hardware accelerated video cards (GPUs).
NoMachine and H.264 software acceleration (MPEG-4 AVC libraries)
H.264 software acceleration is used when the server or client doesn't have the necessary hardware requirements to use HW acceleration.
NoMachine supports H.264 software acceleration for these types of sessions:
(i) Connections to the remote physical desktop.
(ii) Linux virtual desktops without activating X11 vector graphics mode.
(iii) Linux virtual desktops in X11 vector graphics mode.
(iv) Multimedia content in custom sessions.
In the case of virtual desktops in X11 vector graphics mode and custom sessions, video streaming techniques, and therefore H.264 SW acceleration, are applied only to multimedia contents. The X11 vector graphics mode is not available for web sessions.
For older NoMachine versions
1) All server products distributed under a customer's subscription (e.g., NoMachine Workstation, Terminal Server and so on) include the MPEG-LA H.264 software encoding/decoding libraries. H.264 software encoding is therefore fully supported. No further action is necessary.
2) NoMachine server packages for evaluation up to v. 6.6.8 didn't include the H.264 encoder. We recommend to upgrade the installation.
3) The NoMachine free version up to v. 6.6.8 was not including the H.264 encoder. If you're still running and older version, please upgrade your installation or refer to instructions for compiling and installing the libx264 library: https://www.nomachine.com/AR10K00695.
4) NoMachine Enterprise Client packages previous than v. 6.6.8 didn't include the H.264 libraries for software encoding. If you're still running and older version, please upgrade your installation or refer to the following instructions to install FFMPEG: https://www.nomachine.com/AR10K00696.
5) The NoMachine AVC Pack (obsolete) was an add-on software for the NoMachine (free) and NoMachine Enterprise Client packages for providing the necessary libraries for H.264 software encoding/decoding. With the release of 6.6.8, the AVC Pack is no longer necessary on either the connecting client or the remote host.
When you purchase a license for any of the NoMachine for the Enterprise products whether it's online via our store or by submitting a PO to one of our sales offices or partners, you will receive an email containing your customer ID and password for your dedicated customer account on the NoMachine website. There will be a license key attached to this email. The license is also made available for you to download from the Customer Area.
To activate your license you must first download and install the corresponding software product in the section "Products Download" (the software is labelled 'Product Version') from your Customer Area by logging first with the credentials mentioned above.
Annual subscriptions are available for any of the enterprise-oriented products from the store. The subscriptions we offer give access to a number of features which are not available in the free version, and can vary depending on the product you choose.
An active subscription of any of the NoMachine for the Enterprise includes one year of:
- Access to free minor and major upgrades, hot fixes and other patches
- Access to technical support and resources you can trust
To keep a subscription active customers are invited to renew prior to the expiry date. Renewing your subscription ensures that technical assistance is always available to you and you don't miss out on any important software or security updates. It's possible to renew from the customer area or directly via one of our Sales Centers.
Not renewing the subscription means that updates and technical assistance will no longer be available. The software will continue to work as expired software.
Your account, which is accessible from the Customer Area, deals with your subscription and purchase history. It's also possible to renew your subscription from the Customer Area, add support contacts and download the software for your purchased subscriptions.You can access it by logging in with your Customer ID and password from:
If access has been turned off to your computer and you want to turn it back on again, follow these steps:
- Open the NoMachine User Interface from your Programs or Applications.
- Click on the 'Settings' icon button to open the Preferences GUI.
- Click on the 'Server status' at the bottom of the panel.
- Click on 'Start the server'.
How to switch off access to the desktop: if you don't want to use the computer where you have installed NoMachine as a server, you can disable access to the desktop by turning off connections. Follow steps here:
- Click on the Monitor (the !M icon) in the system tray to open the menu.
- Click on 'Show the service status'.
- Click on the 'Shutdown the server' button.
- You can select to shutdown the server permanently or re-enable it at reboot.
NoMachine server products take into consideration the number of connections and, in the case of the Terminal Server family for Linux, also the number of concurrent virtual desktops.
The connections limit counter counts all types of connections. These can be connections to the physical desktop, to virtual desktops, custom sessions, sessions which have been reconnected, and also sessions connected to other users' virtual desktops.
The virtual desktops limit counter counts only new virtual sessions (desktop or custom), and as mentioned above, virtual desktops are only available in the Terminal Server for Linux products: Workstation, Small Business Server, Terminal Server and Enterprise Terminal Server.
When a user connects, the connections limit counter is always increased, while the virtual desktops limit counter is increased only when the user creates a new virtual desktop or a new custom session.
When a user disconnects, the connections-limit counter is decreased. The virtual desktops limit counter is decreased only when the user explicitly terminates the virtual desktop or custom session running on the Linux Terminal Server host.
Limits on concurrent virtual desktops and concurrent connections explained
If you create a support ticket on our website or are seeking help in one of the forums, in most cases our support team will ask you to send them your log files. Within these log files various connection and software problems are being recorded, and they will help us to identify the possible cause of the problem you are encountering.
Submitting logs requires that you create a compressed archive of the NoMachine /var/log directory, and then send this archive by e-mail to appropriate email address, specifying the number of the support ticket or a link to the post in the forum. There are specific steps to follow to extract the logs (once you have reproduced the problem you are reporting). At the bottom of this article you will find the link to those instructions.
Locating the /var/log folder of NoMachine on Windows
NoMachine's /var/log folder on Windows is:
%PROGRAMDATA%/NoMachine/var/log on Windows Vista, 7 and later
Documents and Settings/All Users/NoMachine/var/log on Windows XP
To compress it, right-click the file or folder, point to Send To, and then click Compressed (zipped) Folder.
Locating the /var/log folder of NoMachine on Mac
The NoMachine /var/log folder on Mac is:
To compress it, control-click or right-click the folder and then from the pop-up menu, choose and click on Create Archive.
As an alternative, create a tar.gz archive from command line. Run a terminal and move to /Library/Application Support/NoMachine/var :
$ cd /Library/Application Support/NoMachine/var/
$ sudo tar cvfz NoMachine-log.tar.gz log
Locating the NoMachine /var/log directory on Linux
The NoMachine /var/log directory on Linux is:
Create a compressed archive (tar.gz) archive from command line. Run a terminal and move to /usr/NX/var :
Browser-based remote access is available in all of the pay-for 'server' products: Enterprise Desktop, Cloud Server and the whole Terminal Server for Linux range. These are all labelled 'Subscriptions' in the store.
If you have installed the free version of NoMachine on the remote host you want to access, you will need the NoMachine package or Enterprise Client on the connecting device in order to connect. Access via the browser of the connecting client is not supported.
If you are looking for an alternative to the free version for remote desktop access to your Windows, Linux or Mac computers, we recommend you try Enterprise Desktop. By installing it on the computer you want to access, you will be able to use an HTML-enabled browser on the connecting device to connect to it.
Check out the comparison of NoMachine and NoMachine Enterprise Desktop software products (https://www.nomachine.com/remote-access-for-your-needs).
Enterprise Client is the connection GUI package that you install on the local machine in order to connect to your remote host where you must have installed either the free NoMachine product or one of the Enterprise-oriented server versions.
Enterprise Client does not expire and it is free to download, install and use.
Installing NoMachine on an iPhone in order to access that device from another device or computer is not possible. To access a remote host with NoMachine, the supported operating systems are Raspberry, Linux, Windows and macOS.
As a connecting client, NoMachine can be installed on iOS, Android, Raspberry, Linux, Windows and macOS.
NoMachine (free) allows one connection. If you are working on your local desktop (i.e sitting in front of it) and you would like a colleague or friend to connect to it so that they can collaborate on a document or interact with you, they will be able to connect. This is considered 'one connection'. They must install NoMachine for their operating system on their computer or device. On the other hand, if you are connecting to your desktop remotely, you will not be able to have a friend connect at the same time. This would be considered two connections. If you want two users to connect simultaneously to a remote computer, you should opt for Enterprise Desktop.
To let your friend or colleague connect, you will need to create an account for them on your computer and send them your IP and port number, so they can access over the Internet. To get your IP and port number, open server settings from the monitor or connection GUI. The IP and port details which must be inserted in the connection GUI on the client side will be indicated there. Upon connecting they will see your desktop and be able to interact with you, or just view.
The first thing to do is to download and install NoMachine on to the computer you want to be able to access. It's free for personal use and allows one connection. You will need to know the computer's public-facing IP address in order to be able to connect to it over the internet. Then download the NoMachine app for iPad which you will use as the connecting client, it's available in the iTunes app store.
If you want an illustrated guide, check out the tutorials:
Note that if you have installed a product which supports virtual Linux desktops (e.g Workstation) users will still be able to run virtual desktop sessions on the NoMachine server host even though "Accepting connections" is disabled.
TIP: if you want to prevent all users and all connections, select 'Stop the server' in the GUI. This will switch off server access. Further reading: https://www.nomachine.com/AR07M00852.
All Enterprise software is available for evaluation from the website with the exception of Small Business Server Subscription and provides you with a 30-day period of evaluation, after which you can decide to purchase a subscription or continue your evaluation. To continue your evaluation you will have to make a fresh installation of the software.
Follow the link http://www.nomachine.com/download-enterprise and download the product you would like to test. The software available on our website comes with the evaluation keys already in place, and is activated upon successful installation.
Technical assistance from the team is not available with evaluation software. The online knowledge base and documents section is a good place to start for questions concerning installation, configuration and eventual troubleshooting. Should you encounter issues that you can't find answers for, please use the Contact Us link to send us your questions. There are also forums available for the Cloud Server and Terminal Server families which can handle basic configuration and installation questions.
Customers can receive extended evaluation keys in special circumstances. Please contact our sales team for more information.
NoMachine software is not licensed per connection, nor per connecting client to the remote host. NoMachine software is licensed per server. A server is the remote host you want to connect to. This remote host can be either a physical or virtual machine and once the appropriate server-side NoMachine package is installed, you connect to it to access a desktop or application running there. Licenses to use any of the pay-for 'server' products are available as subscriptions.
Subscriptions are currently available for Enterprise Desktop, Cloud Server and the Terminal Server range.To allow customers to try the product before purchasing, we make evaluation versions freely available for download. Depending on the product, a pay-for subscription offers a number of benefits including technical assistance and updates to the software. The duration of a subscription is by default one year, after which customers should renew to continue to receive the same benefits as before.
On the connecting client, it's possible to install either of the free NoMachine or Enterprise Client packages. These are available for a number of operating systems and you can download and install either as many times as you like. There is no fee for the free NoMachine software, nor for Enterprise Client.
This article refers to the freely available 'NoMachine' package - free for personal use. If you are using an Enterprise product from NoMachine, please log in to your Customer Area and proceed to the 'Support Enquiries' section you can find there. The support team will be able to assist you.
Remember that you need two computers to run NoMachine: the one you are connecting from and the one you which to connect to.
NoMachine for Linux
If you are trying to install NoMachine on Linux, bear in mind that we tested the installation on thousands of machines with thousands of different desktop environments and Linux versions, but of course we can't guarantee that it will work on your computer, with your version of Linux. So, if you have a problem, try to post it on the forums, including all the information we list in "What to provide". What we strongly suggest is to be sure you removed all residuals of version 3 you had before, especially if they were NX installations not from NoMachine. We've seen NX installations from products using our open-source software failing to uninstall correctly and interfering every attempt of NoMachine to run on the same computer later.
NoMachine for Windows or Mac
If you are on Windows or Mac, the installation should be even more straightforward.
Most problems people report are connectivity problems due to the firewall or the antivirus installed on the machine accepting the connection, with the firewall or antivirus blocking access from another computer.
If you need further help, ask in the Forums and one of the Forum members will try to help.
You must connect to the remote desktop to be able to then connect a local disk or a remote disk. By connecting a local disk, you will be exporting its contents to the remote desktop. By connecting a remote disk, you will be importing files to the local desktop, i.e., the client you are connecting from, effectively allowing you to access file system resources as if they were on your local computer. This is done via the session's menu panel (activated by pressing Ctrl-Alt-0) and selecting 'Connect a disk'. NoMachine will show you the disks available for connecting by distinguishing between 'Local disks' and 'Remote disks' ready to be used in the session.
Consult section 4 in 'Guide to the Functionality in the Menu Panel for Linux/Windows/Mac' in the Documents section of the Knowledge Base, or go to the Configuration section of https://www.nomachine.com/all-documents web page.
In order to run a virtual desktop session on Linux, you need to install any of the Linux products from the Enterprise range, with the exception of Enterprise Desktop, on the remote host. NoMachine for the Enterprise products (30 days evaluation version) can be downloaded from here: http://www.nomachine.com/download-enterprise
To connect, you can use the NoMachine or Enterprise Client packages or a browser.
The free to download NoMachine for Linux package doesn't support the 'virtual desktop' functionality. It connects to the physical desktop of the remote host.
Once authenticated to a host with virtual desktop support enabled, you will see a button '+' to let you 'Create a new virtual desktop', or click on the 'New virtual desktop or custom session' link. Any sessions that you previously ran from the client computer you are connecting from will be listed in the connection list of this panel.
When getting this message in v. 6, it's likely you are trying to connect to the remote computer using the SSH protocol but the NoMachine server is not installed there.
With previous versions, a similar message:
The NoMachine service is not available or the access was disabled on host ---.---.---.---
is issued when trying to connect to a NoMachine server v. 5 or 4 which doesn't support SSH. All enterprise-oriented products (in the NoMachine for the Enterprise) support SSH connections. The free to download NoMachine product doesn't.
In this case you will have to select the NX protocol in connection settings -> Edit connection -> protocol.
This same message can be also displayed in other cases, all depending on the fact the server was contacted by the client using the SSH service while the NoMachine server was either stopped or the SSH access was disabled. See also: https://www.nomachine.com/AR12K00760
Running a single Linux application or an application in rootless/seamless or floating window mode is possible with any of the products that support the virtual desktop functionality like Workstation, Small Business Server, Terminal Server and Enterprise Terminal Server.
To run a Linux application in floating window, the option 'Create a new custom session' must be selected from the panel presented to you once you have logged in.
From there you will then be able to indicate the path to the application on the remote host and select whether to run the application in floating window or as a virtual desktop (see https://www.nomachine.com/DT04O00140#4.2. for more details about running virtual desktops and custom sessions).
NoMachine software currently can be updated in two ways. Either by selecting the automatic updates option in the user interface, or manually by downloading the latest package from our website and then installing according to the standard procedure for your operating system.
Using automatic updates:
The NoMachine software by default fetches our repositories every two days but updates are never installed automatically.
To disable the automatic check or change the update frequency, please refer to instructions at:
- Download and save the EXE file.
- Double click on the NoMachine executable file.
- The Setup Wizard will take you through all steps necessary for updating NoMachine.
NoMachine on Mac:
- Download and save the DMG file.
- Double-click on the Disk Image to open it and double-click on the NoMachine program icon.
- The Installer will take you through through all steps necessary for updating NoMachine.
NoMachine on Linux:
You can use the graphical package manager provided by your Linux distribution or update NoMachine by command line by following instructions below.
If you don't have the sudo utility installed, log on as superuser ("root") and run the commands without sudo
- Download and save the RPM file.
- Update your NoMachine installation by running:
# rpm -Uvh <pkgName>_<pkgVersion>_<arch>.rpm
- Download and save the DEB file.
- Update your NoMachine installation by running:
$ sudo dpkg -i <pkgName>_<pkgVersion>_<arch>.deb
- Download and save the TAR.GZ file.
- Update your NoMachine installation by running:
$ cd /usr
$ sudo tar xvzf <pkgName>_<pkgVersion>_<arch>.tar.gz
$ sudo /usr/NX/nxserver --update
If you are installing Enterprise Client or Terminal Server Node run respectively:
Since v. 4, NoMachine implements its own protocol for secure communication over the network. The products targeting commercial use, so both of the Enterprise Server and Terminal Server families, additionally support the SSH protocol out of the box. All products use the NX protocol as default. There are multiple reasons for using our own protocol rather than SSH.
The first is performance. Tunneling over SSH means that our packets have to traverse at least 1 additional process before coming to the destination (at least the SSHD process, if we don’t run a separate SSH client). This is an additional process for each machine traversed, so in a multi-node server there are at least two. Then with SSH we have processes communicating through pipes (like multiple separate commands piped in a shell), so we are adding a further encryption stage at each hop.
With NX we can simply hand over the SSL context from one process to the next (as Apache does) and relay connections by only running encryption end-to-end. We can’t provide the details, but we were in a situation where a display packet, to come to the client, had to traverse 12 processes and be encrypted 3 times. Not so with the NX protocol.
Additionally, when using the NX protocol, audio and video can use UDP. Not that we couldn’t use a UDP side-channel with SSH, but it would have been hard to explain to managers in a company that, yes, we use SSH for the connection but then most data is not going through SSH. There are additional tiny details, like the efficiency of the crypto key used, that adds to the speed, or the fact that SSHD is a single-threaded process while with NX everything is multi-threaded and can run on platforms, like iOS, where multi-process is not an option.
A second reason is that, using SSH, we can’t simply support a number of features we need in NX, like keeping a NX users separate from the system users, supporting guest connections and redirecting users to different machines without having to create system accounts. Unless recurring to workarounds. That is what we did with the use of the “NoMachine login”. These workarounds are perfectly in the spirit of SSH but were judged “questionable” by some, simply because they by-passed PAM and let NoMachine create users and check passwords on its own. With the NX protocol these “questionable” uses of SSHD are gone.
A third reason is Windows. We ported the OpenSSH client and server to native Windows and released it on the same licensing terms of OpenSSH. This was done to offer the same set of features on all platforms, but it's not in our plans to develop further SSH for Windows.
A fourth reason is supportability. It’s hard to support something you have no control over how it is used or configured. SSH is an extremely powerful and configurable tool. When users install NoMachine and NoMachine doesn’t work because the SSH client or server are configured to do something special that we could not foresee, users tend to blame NoMachine. This is well within their rights to do so, but now having two distinct protocol options, enterprise users can still use SSH if they want, but at least we will know if a problem they report is due to SSH or NoMachine.
When trying to connect by using the SSH protocol, sometimes the NoMachine client issues the following message:
The session negotiation failed.
Error: NX access is disabled
Possible reasons for getting this message are:
- The server has been stopped, i.e. it doesn't accept new connections.
Be sure that the server is up and running, you can start it from the NoMachine monitor in your system tray: select 'Show the service status' and click on 'Start the server'.
- The server has been shutdown, i.e. all NoMachine services, included the Monitor in the system tray, have been stopped.
Be sure that all NoMachine services are up and running, you can start them from the NoMachine User Interface: click on 'Settings' to open the Preferences GUI and then click on the 'Server status' icon at the bottom of the panel to open the Service Status panel. Click on 'Start the server'.
NoMachine is not AdWare crap. We don't scan your disk, track your location, read your e-mail or sell your browsing habits. For NoMachine software is a product, just like food or clothing. People should choose and buy for its quality, not because it's free. Even when we give away our software for free (as we do), free-of-cost is just a marketing tactic. We do this to make the software known and used by a larger public, so that we can improve it and make it more attractive for the paying customers. Just as we wouldn't wear clothing that tracks where we go, or eat food that tells the vendor what other food we have eaten, we don't give our users software in exchange of some of their liberties. It's an old business model, but we prefer it. Remember that when something is free the product is you.
Yes. You will still be able to use your software but you will not be able to take advantage of the upgrades for it. Attempting to upgrade expired NoMachine server software will interfere with the correct functioning of it.