Difference between revisions of "FreeNX"

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The NX protocol aims at offering a stateful desktop session to remote users, like [[VNC]]. The most prominent difference is that NX requires less bandwidth. FreeNX is one implementation of the [[NX]] protocol.
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FreeNX allows you to set up a [[terminal server]].
  
= QuickStart =
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= How NX works =
In this chapter, the SUSE Linux [[distribution]] is used as example.
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* You call nxclient with your user
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* nxclient uses the nx user to connect to the NX server. This authentication works passwordless with a private key (the nomachine-key) in your nxclient and an authorized public key on the nx server. Private and public key must fit to each other.
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* nx's shell on the NX server is called nxserver which allows communication over the nx protocol
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* now your user name and password is transmitted and checked
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* then nxserver establishes the display connection
  
* [[Install]] [[FreeNX]]
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= SUSE 13.1 =
[[yast]] -i FreeNX
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This is how I installed a FreeNX server on SUSE 13.1 on 2014-07-19:
* Setup FreeNX:
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* [[open a console]] and enter
nxsetup
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  # yast -i expect rdesktop
: continue as advised. The NX server is started automatically.
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  # wget http://download.opensuse.org/repositories/home:/beyerle:/NX/openSUSE_13.1/$(uname -i)/NX-3.5.0-123.1.x86_64.rpm
* Connect to the NX server
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  # wget http://download.opensuse.org/repositories/home:/beyerle:/NX/openSUSE_13.1/x86_64/FreeNX-0.7.3-7.1.$(uname -i).rpm
nxclient
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  # rpm -ivh NX-3.5.0-123.1.*.rpm FreeNX-0.7.3-7.1.*.rpm
You can now log in.
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* read how to set it up
 
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  # cat /usr/share/doc/packages/FreeNX/README.SuSE
= Trial 2 =
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* set it up
FreeNX server is not available with SUSE 13.1 so I
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  # nxsetup --setup-nomachine-key
  # yast -i expect
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* Now connect with any NX client to the NX server. The connection does not work for me, I get an error message
  # wget http://download.opensuse.org/repositories/home:/beyerle:/NX/openSUSE_13.1/i586/NX-3.5.0-123.1.i586.rpm
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  The NX service is not available or the NX access
  # wget http://download.opensuse.org/repositories/home:/beyerle:/NX/openSUSE_13.1/i586/FreeNX-0.7.3-7.1.i586.rpm
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  was
  # rpm -ivh NX-3.5.0-123.1.i586.rpm FreeNX-0.7.3-7.1.i586.rpm
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  disabled on host ...
 
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* To solve this problem, you need a private/public key pair. Generate one with the command
now qtnx asks me for a password but I don't know which one
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  ssh-keygen -t dsa
 
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The command will ask where to put the key pair. The private key will be named id_dsa and the public key will be named id_dsa.pub. Add the public key to /var/lib/nxserver/home/.ssh/authorized_keys and import the private key into your NX client. The re-login using your NX client.
but ps -Hef helps:
 
root      4173  3692  3 06:17 pts/4    00:00:00      qtnx
 
root      4174  4173  0 06:17 pts/4    00:00:00        ssh -p22 -iid.key nx@localhost -x -2 -oRhostsAuthentication no -
 
 
 
cat /etc/shadow delivers
 
nx:*:16220::::::
 
 
 
= Trial 3 =
 
  # wget http://download.opensuse.org/repositories/home:/beyerle:/NX/openSUSE_13.1/x86_64/FreeNX-0.7.3-7.1.x86_64.rpm http://download.opensuse.org/repositories/home:/beyerle:/NX/openSUSE_13.1/x86_64/NX-3.5.0-123.1.x86_64.rpm
 
  # yast -i rdesktop libpixman-1-0-devel libpng16-devel fontconfig-devel Mesa-libEGL-devel Mesa-libEGL-devel-32bit fontconfig-devel-32bit freetype2-devel-32bit fontconfig-32bit libxrender-devel-32bit Mesa-libGL-devel-32bit libpixman-1-0-32bit libgobject-2_0-0-32bit libxcb-render-0-32bit libxcb-shm0-32bit cairo-devel cairo-tools cairo-devel-32bit
 
# nxserver --status
 
No such user name: nx
 
NX> 100 NXSERVER - Version 3.2.0-73 OS (GPL, using backend: not detected)
 
  NX> 110 NX Server is stopped
 
  NX> 999 Bye
 
  # nxserver --start
 
No such user name: nx
 
  NX> 100 NXSERVER - Version 3.2.0-73 OS (GPL, using backend: not detected)
 
mv: cannot stat ‘/var/lib/nxserver/home/.ssh/authorized_keys.disabled’: No such file or directory
 
NX> 122 Service started
 
NX> 999 Bye
 
tweedleburg:~ # mkdir -p /var/lib/nxserver
 
tweedleburg:~ # useradd -m -d /var/lib/nxserver/home/ nx
 
  
 
= TroubleShooting =
 
= TroubleShooting =
 
* starting the nxagent, you get
 
* starting the nxagent, you get
 
  /usr/NX/bin/nxagent: error while loading shared libraries: libXcomp.so.3: cannot open shared object file: No such file or directory
 
  /usr/NX/bin/nxagent: error while loading shared libraries: libXcomp.so.3: cannot open shared object file: No such file or directory
: Download nxcomp from http://www.nomachine.com/sources.php and [[install]] it. Copy libXcomp.* to /usr/lib.
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: Download nxcomp from http://software.opensuse.org/package/libXcomp3 and [[install]] it. Copy libXcomp.* to /usr/lib.
  
 
* during nxsetup, you get
 
* during nxsetup, you get
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  Can't open /var/lib/nxserver/db/running/sessionId{CBE6C1DE8281C9A77A5F72F05947EE1F}: No such file or directory.
 
  Can't open /var/lib/nxserver/db/running/sessionId{CBE6C1DE8281C9A77A5F72F05947EE1F}: No such file or directory.
 
  mv: cannot stat `/var/lib/nxserver/db/running/sessionId{CBE6C1DE8281C9A77A5F72F05947EE1F}': No such file or directory
 
  mv: cannot stat `/var/lib/nxserver/db/running/sessionId{CBE6C1DE8281C9A77A5F72F05947EE1F}': No such file or directory
: Possible workaround: re-install the NX server
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: Possible workaround: re-install the NX server using the command
 +
nxsetup
  
 
* You get an error when logging in
 
* You get an error when logging in

Latest revision as of 06:46, 10 August 2014

FreeNX allows you to set up a terminal server.

How NX works

  • You call nxclient with your user
  • nxclient uses the nx user to connect to the NX server. This authentication works passwordless with a private key (the nomachine-key) in your nxclient and an authorized public key on the nx server. Private and public key must fit to each other.
  • nx's shell on the NX server is called nxserver which allows communication over the nx protocol
  • now your user name and password is transmitted and checked
  • then nxserver establishes the display connection

SUSE 13.1

This is how I installed a FreeNX server on SUSE 13.1 on 2014-07-19:

# yast -i expect rdesktop
# wget http://download.opensuse.org/repositories/home:/beyerle:/NX/openSUSE_13.1/$(uname -i)/NX-3.5.0-123.1.x86_64.rpm
# wget http://download.opensuse.org/repositories/home:/beyerle:/NX/openSUSE_13.1/x86_64/FreeNX-0.7.3-7.1.$(uname -i).rpm
# rpm -ivh NX-3.5.0-123.1.*.rpm FreeNX-0.7.3-7.1.*.rpm
  • read how to set it up
# cat /usr/share/doc/packages/FreeNX/README.SuSE
  • set it up
# nxsetup --setup-nomachine-key
  • Now connect with any NX client to the NX server. The connection does not work for me, I get an error message
The NX service is not available or the NX access
was
disabled on host ...
  • To solve this problem, you need a private/public key pair. Generate one with the command
ssh-keygen -t dsa

The command will ask where to put the key pair. The private key will be named id_dsa and the public key will be named id_dsa.pub. Add the public key to /var/lib/nxserver/home/.ssh/authorized_keys and import the private key into your NX client. The re-login using your NX client.

TroubleShooting

  • starting the nxagent, you get
/usr/NX/bin/nxagent: error while loading shared libraries: libXcomp.so.3: cannot open shared object file: No such file or directory
Download nxcomp from http://software.opensuse.org/package/libXcomp3 and install it. Copy libXcomp.* to /usr/lib.
  • during nxsetup, you get
strings: '/usr/bin/nxagent': No such file
Error: Could not find 1.5.0 or 2.[01].0 version string in nxagent. NX 1.5.0 or 2.[01].0 backend is needed for this version of FreeNX.
copy /usr/NX/bin/nxagent to /usr/bin
  • The connection fails during the "Negotiating link parameters" step.
Stop the fireWall on the target computer.
  • The connection fails after the "Authentication completed" step.

you get an error message like that:

NX> 1004 Error: NX Agent exited with exit status 1.
Can't open /var/lib/nxserver/db/running/sessionId{CBE6C1DE8281C9A77A5F72F05947EE1F}: No such file or directory.
mv: cannot stat `/var/lib/nxserver/db/running/sessionId{CBE6C1DE8281C9A77A5F72F05947EE1F}': No such file or directory
Possible workaround: re-install the NX server using the command
nxsetup
  • You get an error when logging in
Test the connection using ssh, there may be no lines of text sent when logging in. So, e.g. not
hello world
$