FreeNX

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.

QuickStart

In this chapter, the SUSE Linux distribution is used as example.

• Install FreeNX

yast -i FreeNX

• Setup FreeNX:

nxsetup

continue as advised. The NX server is started automatically.

• Connect to the NX server

nxclient

You can now log in.

Trial 2

FreeNX server is not available with SUSE 13.1 so I

# yast -i expect rdesktop
# wget http://download.opensuse.org/repositories/home:/beyerle:/NX/openSUSE_13.1/i586/NX-3.5.0-123.1.i586.rpm
# wget http://download.opensuse.org/repositories/home:/beyerle:/NX/openSUSE_13.1/i586/FreeNX-0.7.3-7.1.i586.rpm
# rpm -ivh NX-3.5.0-123.1.i586.rpm FreeNX-0.7.3-7.1.i586.rpm

• read how to set it up

# cat /usr/share/doc/packages/FreeNX/README.SuSE

• set it up

# nxsetup --setup-nomachine-key

now qtnx asks me for a password but I don't know which one

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

Now I get

NX> 203 NXSSH running with pid: 16802
NX> 285 Enabling check on switch command
NX> 285 Enabling skip of SSH config files
NX> 285 Setting the preferred NX options
NX> 200 Connected to address: 127.0.0.1 on port: 22
NX> 202 Authenticating user: nx
NX> 208 Using auth method: publickey
NX> 204 Authentication failed.

Quickly installed everything so nxssh does not return an error.

Now in /root/.nx/temp/3397 I find the logs. runlog says

[Tue Jul 15 14:59:52 2014]: LoginDialog::connectHost() nxsshline=/usr/NX/bin/nxssh -nx -p 22 -i /root/.nx/temp/3397/keylog nx@localhost -x -2 -4 -o RhostsAuthentication no -o PasswordAuthentication no -o RSAAuthentication no -o RhostsRSAAuthentication no -o PubkeyAuthentication yes -B -E

tweedleburg:~/.nx/temp/10416 # /usr/NX/bin/nxssh -nx -p 22 -i /root/.nx/temp/10416/keylog nx@localhost -x -2 -4 -o RhostsAuthentication no -o PasswordAuthentication no -o RSAAuthentication no -o RhostsRSAAuthentication no -o PubkeyAuthentication yes -B -E
NX> 203 NXSSH running with pid: 10937
NX> 200 Connected to address: 127.0.0.1 on port: 22
NX> 202 Authenticating user: nx
NX> 208 Using auth method: publickey
NX> 204 Authentication failed.
tweedleburg:~/.nx/temp/10416 # /usr/NX/bin/nxssh -nx -p 22 nx@localhost -x -2 -4 -o RhostsAuthentication no -o PasswordAuthentication no -o RSAAuthentication no -o RhostsRSAAuthentication no -o PubkeyAuthentication yes -B -E
NX> 203 NXSSH running with pid: 10942
NX> 200 Connected to address: 127.0.0.1 on port: 22
NX> 202 Authenticating user: nx
NX> 208 Using auth method: publickey
HELLO NXSERVER - Version 3.2.0-73 OS (GPL, using backend: 3.5.0)
NX> 105

cp /root/.ssh/id_dsa /usr/NX/share/keys/server.id_dsa.key

Trial 4: SUSE 12.3

• download all files from http://download.opensuse.org/repositories/home:/beyerle:/NX/openSUSE_12.3/x86_64/

# rpm -Uvh cairo-devel-1.12.14-5.1.x86_64.rpm libcairo-gobject2-1.12.14-5.1.x86_64.rpm libcairo-script-interpreter2-1.12.14-5.1.x86_64.rpm libcairo2-1.12.14-5.1.x86_64.rpm
# rpm -Uvh NX-3.5.0-123.1.x86_64.rpm FreeNX-0.7.3-7.1.x86_64.rpm

/var/lib/nxserver/home/.ssh # cat /var/NX/nx/.ssh/default.id_dsa.pub >> authorized_keys

ls3523:/var/lib/nxserver/home/.ssh # nxserver --stop
No processes found.
NX> 100 NXSERVER - Version 3.2.0-73 OS (GPL, using backend: 3.5.0)
NX> 123 Service stopped
NX> 999 Bye
ls3523:/var/lib/nxserver/home/.ssh # nxserver --status
No processes found.
NX> 100 NXSERVER - Version 3.2.0-73 OS (GPL, using backend: 3.5.0)
NX> 110 NX Server is stopped
NX> 999 Bye
ls3523:/var/lib/nxserver/home/.ssh # cp /root/.ssh/id_dsa /usr/NX/share/keys/server.id_dsa.key
ls3523:/var/lib/nxserver/home/.ssh # ssh -i /usr/NX/share/keys/server.id_dsa.key nx@localhost
Password: 

ls3523:/var/lib/nxserver/home/.ssh # cat /root/.ssh/id_dsa.pub > /home/nx/.ssh/authorized_keys
ls3523:/var/lib/nxserver/home/.ssh # nxserver --start
No processes found.
NX> 100 NXSERVER - Version 3.2.0-73 OS (GPL, using backend: 3.5.0)
NX> 122 Service started
NX> 999 Bye
ls3523:/var/lib/nxserver/home/.ssh # nxserver --status
No processes found.
NX> 100 NXSERVER - Version 3.2.0-73 OS (GPL, using backend: 3.5.0)
NX> 110 NX Server is running
NX> 999 Bye
ls3523:/var/lib/nxserver/home/.ssh # ssh -i /usr/NX/share/keys/server.id_dsa.key nx@localhost
Last failed login: Wed Jul 16 17:47:40 CEST 2014 from localhost on ssh:notty
There were 23 failed login attempts since the last successful login.
Have a lot of fun...
/usr/bin/xauth:  file /home/nx/.Xauthority does not exist
nx@ls3523:~> exit
logout
Connection to localhost closed.
ls3523:/var/lib/nxserver/home/.ssh # /usr/NX/bin/nxssh -nx -p 22 -i /root/.nx/temp/10398/keylog nx@localhost -x -2 -4 -o RhostsAuthentication no -o PasswordAuthentication no -o RSAAuthentication no -o RhostsRSAAuthentication no -o PubkeyAuthentication yes -B -E
NX> 203 NXSSH running with pid: 11380
NX> 200 Connected to address: 127.0.0.1 on port: 22
NX> 202 Authenticating user: nx
NX> 208 Using auth method: publickey
bash: no: command not found

/var/lib/nxserver # mkdir -p db/closed
/var/lib/nxserver # mkdir -p db/failed
/var/lib/nxserver # chown -R nx db/

Trial 5: Fedora 20

yum install freenx-server
yum install nxagent
nxsetup

• made sure nx can log in via ssh without key from root
• changed nx config file to contain root's private key
• login worked

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.

• 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

• 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
$