freenx - community documentation

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Contents

What is FreeNXTerminology1.

1.

Installation PrerequisitesInstalling the FreeNX server on UbuntuKarmic (9.10) or Ubuntu Lucid (10.04)or Ubuntu Maverick Meerkat (10.10)

1.

Installing the FreeNX server on olderUbuntu Versions

2.

Installing the NX Client3.Installing QTNX (Opensource client)4.

2.

MiscellanyNX Server Free Edition1.Neatx2.FreeNX on PowerPC3.

How to start/stop FreeNX4.Configuring SSH port5.Using custom SSH keys6.Using Custom SSH keys on Lucid7.

3.

Troubleshooting4.References

Related docs1.Desktop integration wanted2.

5.

Login to Edit

Ubuntu Documentation > Community Documentation > FreeNX

FreeNX

What is FreeNX

FreeNX is a system that allows you to access your desktop from another

machine over the Internet. You can use this to login graphically to your

desktop from a remote location. One example of its use would be to have a

FreeNX server set up on your home computer, and graphically logging in

to the home computer from your work computer, using a FreeNX client.

It's Open Source, secure (SSH based), fast and versatile! License: GPL

Note: Running FreeNX as server on Ubuntu with the free "NX Client for

Windows" from NoMachine on a Windows workstation is working fine,

except resuming sessions.

Terminology

The Server is the computer you want to connect to. This is the computer

where the FreeNX server will need to be installed. The name of the

Ubuntu package providing the server is "freenx". For the example used

here, the home computer is the server.

The Client is the computer from which you want to be able to access the

Server. The name of the Ubuntu package providing the client is "nxclient". For the example used here, the work computer is the

client.

Installation Prerequisites

Before installing FreeNX server make sure you have SSH set up and is working. You can find the SSH Howto here:

https://help.ubuntu.com/community/SSHHowto

We will be installing the FreeNX server on the Server machine, i.e., the machine that you want to access remotely. In the stated

example, this is your computer that is at home.

FreeNX is not included in Ubuntu, so we'll add it from the FreeNX Team PPA. This step will be in the installation instructions

for your Ubuntu distribution of choice below.

For the paranoid: there is an added security risk involved in using the default keys. If you keep the default keys then everybody

will be able to connect to your SSH server as the NX user which is added to your system during the installation. This opens an

additional (and unnecessary) opportunity to attack your computer. You could avoid it by using custom SSH keys, as explained

later.

Installing the FreeNX server on Ubuntu Karmic (9.10) or Ubuntu Lucid (10.04) or Ubuntu

Maverick Meerkat (10.10)

Open your terminal

Applications->Accessories->Terminal

and type in this command

sudo add-apt-repository ppa:freenx-team

NOTE: If you do not have add-apt-repository installed add the following

sudo apt-get install python-software-properties

1.

If you're using Maverick, run

sudo sed -i 's/maverick/lucid/g' /etc/apt/sources.list.d/freenx-team-ppa-maverick.list

As of this writing, there are no packages built for Maverick, but the packages for Lucid seem to work.

2.

FreeNX - Community Ubuntu Documentation file:///Users/apple/Desktop/US2011/How-To-Freenx/howtoinst...

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Then Update Apt

sudo apt-get update

3.

At this point, the repository is added and apt is updated, then install the freenx package.

sudo apt-get install freenx

(note, as of Aug. 16 2010 the above command doesn't install a particular script which appears to be missing from

the package. So after performing the above, download it from here. Next, cd to the directory to where the script wasdownloaded (probably your downloads folder) and unpack it:

tar -xvf nxsetup.tar.gz

Then, copy the script to the proper directory: /usr/lib/nx/ with:

sudo cp nxsetup /usr/lib/nx/nxsetup

4.

Now use nxsetup to install necessary files and create the special user "nx"

sudo /usr/lib/nx/nxsetup --install

5.

Installing the FreeNX server on older Ubuntu Versions

These instructions are for older Ubuntu versions. FreeNX is not included in Ubuntu, so we'll add it from the FreeNX Team PPA.

Add this repository using the Third-Party Sources Tab in Software Sources. When it asks, Reload the information about

available software. Now you can see and install the freenx package in Synaptic Package Manager.

You must edit the configuration files and install by hand:

Add this PPA to it's own list file

sudo bash -c "echo 'deb http://ppa.launchpad.net/freenx-team/ppa/ubuntu VERSION maindeb-src http://ppa.launchpad.net/freenx-team/ppa/ubuntu VERSION main' >> /etc/apt/sources.list.d/freenx.list"

where VERSION can be: dapper, hardy, intrepid or jaunty. More information can be found at FreeNX Team PPA.

1.

Add the public key of FreeNX PPA run:

sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com F3A662B57D580D3A2E98E5152A8E3034D018A4CE

2.

Then Update Apt

sudo apt-get update

3.

After you add the repository, then install the freenx package (using Aptitude to install extra needed packages).

sudo aptitude install freenx

4.

Now use nxsetup to install necessary files and create the special user "nx"


5.

Installing the NX Client

The official NX client is not in the Ubuntu repositories.

You should be able to access your Ubuntu box from any Windows or Linux box using the free client from NoMachine's website.

You can also embed your NX Server in a webpage by installing the Nomachine Web Companion and the Apache webserver.

Now you can execute the installed client using the following command:

/usr/NX/bin/nxclient &

Or by looking it up in the menu

This will start the NX client in a GUI, and step you through getting connected to the FreeNX server, and you will be on your

way! [Note: If you are behind a firewall you may need to enable SSL encryption under the Advanced configuration tab -

JeremySchroeder]


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Installing QTNX (Opensource client)

sudo apt-get install qtnx

Miscellany

NX Server Free Edition

NX Server Free Edition provided by NoMachine is not related to FreeNX. NXSFE has a limit of 2 sessions per server. FreeNX

doesn't have this limit.

Neatx

Neatx is a similar system to FreeNX, produced by Google.

It's Open Source, secure (SSH based), but does have some feature drawbacks compared to FreeNX. License: GPL2

FreeNX on PowerPC

There are no precompiled binaries of FreeNX on this platform (Launchpad PPA doesn't provide support), so FreeNX have to be

compiled from source. Sources can be found at the FreeNX Team PPA.

These steps will build FreeNX from source (you need to add the deb-src repository):

Create a directory to hold the FreeNX source, and cd into it.

mkdir freenxSource; cd freenxSource

1.

Build the freenx packages and install related packages.

sudo apt-get build-dep nx freenxapt-get -b source nx freenx

This will download the source tarballs and build the freenx packages (*.deb) in the current directory.

2.

Install the FreeNX packages.

sudo dpkg -i *.deb

3.

If dpkg complains about missing packages, let apt fix it

sudo apt-get -f installsudo dpkg -i *.deb

4.

How to start/stop FreeNX

The FreeNX server is not a service but uses ssh. The following command will stop the FreeNX program from accepting

connections.

sudo /etc/init.d/freenx-server stop

(Replace stop by start for starting it again)

Configuring SSH port

By default, nxserver uses port 22 for communicating over SSH. On some machines or networks, port 22 may be blocked; some

Internet providers block port 22, for instance. Port 22 is also a common target of people trying to crack into a network. To make

the SSH server listen on port 8888, you can do the following:

Edit the file /etc/ssh/sshd_config

gksudo gedit /etc/ssh/sshd_config

Find

Port 22

and change it to

Port 8888

You then need to restart SSHD. Try


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/etc/init.d/ssh restart

FreeNX should detect the SSHD port, but otherwise: Edit the file /etc/nxserver/node.conf

gksudo gedit /etc/nxserver/node.conf

Find

# The port number where local 'sshd' is listening.

#SSHD_PORT=22

and change it to:

# The port number where local 'sshd' is listening.SSHD_PORT=8888

That is, change the port number to the one that sshd is listening to, and uncomment the line.

Using custom SSH keys

After installation, FreeNX will use a set of default ssh keys for authentication. This is a security risk, especially on any internet-

facing machines, and the default keys should be replaced with your own custom keys.

To change the default keys to your own custom keys - on the machine hosting the freenx-server, run the command:

sudo dpkg-reconfigure freenx-server

This will launch a dialogue that will guide you through the generation of custom keys. On the first page hit 'OK' and on the

second page select 'Create new custom keys'

a key file called client.id_dsa.key will be created in: /var/lib/nxserver/home/.ssh/

Now, we need to transfer the key to the client machine so that it can be imported in the FreeNX client application. First copy the

key to your home directory on the server machine:

sudo cp /var/lib/nxserver/home/.ssh/client.id_dsa.key ~/

Next, copy client.id_dsa.key to your client machine. Ideally you should copy the file securely, for example by running the

following command from the client computer:

scp user@freenx-server:~/client.id_dsa.key ~/

which will securely copy the client.id_dsa.key file from the freenx-server computer to your home directory on the client.

If your client is a Windows machine, just copy the key with your preferred method.

In the nx client software you can now import this key.

After you have tested that authentication is working using your custom keys you should then remove the client.id_dsa.key file

from your home directories on both the server and client machines.

Using Custom SSH keys on Lucid

Summary: When finished, a custom key should have been created, and you should be able log into the remote machine with avalid userid id and password that belongs to the server and client.

Objective:

Custom Keys.

User ID and Password.

Authentication method: PASSDB. (PASSDB: Uses an internal user database.)

Adding the PPA repos

deb http://ppa.launchpad.net/freenx-team/ppa/ubuntu lucid main

deb-src http://ppa.launchpad.net/freenx-team/ppa/ubuntu lucid main

You can add them from Menu > System > Administration > Software Sources

Click the Other Software Tab > Click Add and paste each line separately.


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From the terminal:

sudo vi /etc/apt/sources.list.d/freenxi (insert) > pasteesc > :wq

Update sources and install freenx

sudo aptitude updatesudo apt-get install freenx

Check for, and or Download and Install nxsetup

ls -l /usr/lib/nx/nxsetup

Get NXSETUP

Unpack it:

In Nautilus,navigate to where you downloaded nxsetup > right click on the file to get the context menu, and then select Extract

Here

At the terminal:

$tar -xvzf nxsetup.tar.gz

Install it:

chmod 755 nxsetupsudo cp nxsetup /usr/lib/nx/sudo chown root:root /usr/lib/nx/nxsetup


I told it to Y for custom keys, but it did not happen.

Enabling the PASSDB database

Now, since i opted to use 'PASSDB' as the authentication method, the following also has to be done:

Be sure that the /etc/nxserver/node.conf file contains the following line:

ENABLE_PASSDB_AUTHENTICATION="1"

Adding the User ID and Password to the database:

Add yourself to the nxserver database. Suppose your username is jra:

sudo nxserver --adduser jraNX> 100 NXSERVER - Version 3.2.0-74-SVN OS (GPL, using backend: 3.3.0)NX> 1000 NXNODE - Version 3.2.0-74-SVN OS (GPL, using backend: 3.3.0)NX> 716 Public key added to: /home/jawara/.ssh/authorized_keys2NX> 1001 Bye.NX> 999 Bye

Assign a password for jra:

sudo nxserver --passwd jraNX> 100 NXSERVER - Version 3.2.0-74-SVN OS (GPL, using backend: 3.3.0)New password:Password changed.NX> 999 Bye

Adding SSH permissions for the users.

Add nx and jra user ids to sshd_config:

I did it under the Authentication section.

sudo vi /etc/ssh/sshd_configi (insert) AllowUsers nx jra

Save the file.

esc > :wq


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Restart the SSH service.

$sudo service sshd restart* Restarting OpenBSD Secure Shell serversshd [ OK ]

Generate the custom keys.

sudo /usr/lib/nx/nxkeygen

Backing up existing client key to /var/lib/nxserver/home/.ssh/client.id_dsa.key.20101117-131539 Unique key generated; your

users must install

/var/lib/nxserver/home/.ssh/client.id_dsa.key

on their computers.

The key file, client.id_dsa.key, will be in: /var/lib/nxserver/home/.ssh/

Now, we need to securely transfer /var/lib/nxserver/hone/.ssh/client.id_dsa.keyto the client machine so that it can be imported

into nxclient .

Now securely transfer the file from the freenx-server, to home directory on your client machine.

scp source destination

sudo scp /var/lib/nxserver/home/.ssh/client.id_dsa.key [email protected]:''

For safety, do delete the ~/client.id_dsa.key from your client machine when finished.

Download and Install the nxclient.

From website: Get NXClient

or in your terminal with wget,

wget http://64.34.161.181/download/3.4.0/Linux/nxclient_3.4.0-7_i386.deb

Install with GDebi from the Nautilus context menu, if installed, or in the terminal with,

sudo dpkg -i nxclient_3.4.0-7_i386.deb

From your menu Open the NX Connection Wizard.

Enter a Session Name,

Enter Hostname (or IP Address),

Enter Port number or keep the default,

Select your Type of connection I chose LAN, and select Next.

Next:

Select the Desktop System you want to use (Gnome or KDE),

Set the Desktop Size (1024x768),

Do not check the disable encryption box if you want SSL encryption.

Select Next when finished.

Next:

Now, choose if you want to Create shortcut on desktop.

Select Show the Advanced Configuration dialog box.

Click Finish.

Importing the custom key file client.id_dsa.key.

In the advanced dialog window under the General Tab, you should see the items you have already entered, and to the right of Remember my password there is a Key... button.

Click the Key button, a window will popup initially displaying the Default Key


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Now, Click the Import button, navigate to the directory where you saved the client.id_dsa.key file you copied from the server,

and select it to open and import the key. You show now see the custom keys which should be different from the initial default

key.

Click Save > Save > Ok.

You should now be presented with a login prompt, displaying your,

Login: User ID

Password: Blank

Session: session name

Just enter the password you added too the nxserver database, Click Login, the nxclient will make's the connection, and once

there are no errors, you should be on your remote machine.

If your client is a Windows machine, just copy the key with your preferred method.

In the nx client software you can now import this key.

After you have tested that authentication is working using your custom keys you should then remove the client.id_dsa.key file

from your home directories on both the server and client machines.

Troubleshooting

Problem: Everything is installed as described above, but I still get errors at installing nxsetup --install

Solution: Check that this line exists in /etc/ssh/sshd_config " AllowUsers nx" and this line also exists and is set to

authorized_keys2 " AuthorizedKeysFile %h/.ssh/authorized_keys2 ", if commented, just uncomment them. after that run

this command in a terminal sudo /etc/init.d/ssh restart .This issue is due custom SSH server configuration.

Problem: At the client, the !M logo window appears, but after a few seconds that window just closes, even without

showing any error message.

Solution: In the server, access your home directory and run this command, sudo rm .Xauthority* followed by

touch .Xauthority and finally chmod 600 .Xauthority . This issue is due custom VNC configuration.

Problem: What can I do if I get the error 'Could not yet establish the connection to the remote proxy' ?

Solution: This commonly happens when the Advanced tab configuration option "Disable encryption of all traffic" has

been selected, but the appropriate firewall ports have not been opened. Open the necessary firewall ports, or uncheck the

option to re-enable encryption over SSH. NoMachine knowledge base article

Problem: NX Client connects and displays the desktop but the screen does not refresh.

Solution: Set Disable Direct Draw for screen rendering in the client's advanced configuration tab.

Problem: NX Client authenticates user NX and tries to authenticate normal user but then fails with:

Permission denied (publickey). NX> 280 Exiting on signal: 15.

Solution: Set authentication = SU in /etc/nxserver/node.conf. All other authentication methods set to "0". Automated

Solution and workaround credit: this thread

Problem: NX session started from Linux client cannot be resumed on Windows client (http://mail.kde.org/pipermail

/freenx-knx/2011-January/009152.html)

Solution: Apply the patch posted on https://bugs.launchpad.net/freenx-server/+bug/589723/comments/25 to /usr/lib

/nx/nxserver. Then restart the nxserver with sudo nxserver --restart.

References

FreeNX on Wikipedia

FreeNX project page on BerliOS

FreeNX Team PPA An up-to-date repository from the FreeNX Team, for Ubuntu 8.04 (Hardy), 8.10 (Intrepid) or 9.04

(Jaunty)

Seveas' Packages FreeNX old repository

Ubuntu Forums HowTo FreeNx How to remote desktop using SSH and FreeNX - OpenGL Seveas Repositories

Ubuntu Forums Install FreeNX in Ubuntu 10.4 Lucid

From the CentOS Wiki

Related docs

You can also have a look at the article about installing the NX packages provided by NoMachine company

Desktop integration wanted


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For those who want to have freenx supported in krfb, krdc, log into bugs.kde.org, and add a comment and vote for the following

bugs (wishlist) :

187310 : nxserver support in krfb

149482 :nx support in krdc (client), it seems that work is already in progress, and there only a few problems left.

The same should be done on gnome side, for vino and vinagre.

comment-77547 : vinagre has a plan to support nx

vino goals/to-do v2 : no mention of nx; only rdp and vnc

NXLaunch is another solution and could possibly be integrated in other Remote Desktop clients.

msg00330, 2007-Sept : committed source

msg00404, 2007-Sept : integration

CategoryInternet CategoryNetworking CategoryNetworking CategoryInstallation CategoryAudio

FreeNX (last edited 2011-05-11 07:22:53 by https://login.launchpad.net/+id/ByrCsdA @ vpn-3206.gwdg.de[134.76.3.206]:j.eng)

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