/usr/NX/bin/nxserver –keygen … Please, I want the last two hours of my life back!

As good as Nomachine’s NX is … the documentation is seriously confusing  and all over the place with some documents more complete than others.

I tried to check out their new 4.x preview just yet (oh, and no, it’s definitely not ready for production), and as I always do, generate my own keys to go with it. But after the usual /usr/NX/bin/nxserver –keygen, a restart failed with

NX> 500 ERROR: Cannot start service: nxserver
NX> 500 Authentication as user nx using the NX SSH key-pair failed.
NX> 500 This may be due to the configuration of your SSH server. Please
NX> 500 ensure that the location and file name of the SSH authorized
NX> 500 keys is the same in both the SSHD and NX server configuration
NX> 500 files and that the nx user is listed among the accepted users
NX> 500 in the SSHD configuration file.
NX> 999 Bye.

Got seriously frustrated, because all seemed well according to documentation. Well, it seems like there is one important step missing – renaming or copying

/usr/NX/share/keys/default.id_dsa.key

to

/usr/NX/share/keys/server.id_dsa.key

If you don’t do that, nxserver will happily continue to use its prior key (which makes sense I guess, you aren’t going into production with new keys the second you generate them) while the nx user will already have the new keys in place.

So basically the procedure is:

# /etc/init.d/nxserver stop
# /usr/NX/bin/nxserver --keygen
# chown nx:root /usr/NX/home/nx/.ssh/authorized_keys2
# chmod 0644 /usr/NX/home/nx/.ssh/authorized_keys2
# chown nx:root /usr/NX/home/nx/.ssh/default.id_dsa.pub
# chmod 0644 /usr/NX/home/nx/.ssh/default.id_dsa.pub 
# cp /usr/NX/share/keys/default.id_dsa.key /usr/NX/share/keys/server.id_dsa.key
# /etc/init.d/nxserver start

Of course, your client(s) will also need to import the new server key.

NoMachine NX, Ubuntu and the XSession

If you get the dreaded

'Cannot run /etc/X11/xdm/Xsession ...'

when requesting a new session on an Ubuntu server, this – at least for me – fixed it:

sudo mkdir /etc/X11/xdm && sudo ln -s /etc/X11/Xsession /etc/X11/xdm/Xsession

Installing NoMachine NX on ArchLinux

Pain in the butt… if you don’t know you need to specify redhat as system. From then on it’s smooth sailing. Download from nomachine.com and then:

# switch to root
cd /usr
tar xfvz <nxnode-whatever is current version now>
tar xfvz <nxclient-whatever is current version now>
tar xfvz <nxserver-whatever is current version now>
ln -s /etc/rc.d /etc/init.d
/usr/NX/scripts/setup/nxnode –install redhat
/usr/NX/scripts/setup/nxserver –install redhat
rm /etc/init.d

That’s pretty much it. You might want to create your own keys instead of the default NoMachine keys by doing /usr/NX/scripts/setup/nxserver --keygen, but it’s not required.

(Yes, I know – there is FreeNX in the Arch repositories. It works… kind of. Resuming a session from Windows to Linux and vice versa might work, but usually does not. Hence for personal use I prefer the original NoMachine distribution – the two connection limit is usually more than enough. PS: Did I say I love NX? It’s an awesome product in so many ways.)