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Re: FreeNX

Ralf Gesel|ensetter skrev:

Hi Ragnar,

thank you for rising that topic. For Ulsrud, I planned to demonstrate nx access to my school's system. Anyone interested?

Am Donnerstag, 27. Januar 2005 16:50 schrieb Ragnar Wisløff:
I've just had my first session with FreeNX in an LTSP environment
today. First impressions are mixed. The compression is impressive,
for flash movies more than 100x. But for interactive sessions the

latency renders the page almost useless. The colour depth is less,
some icons are off and text is misplaced sometimes. General

Latency is usually a result of round trips, which can be avoided by the use of nxagent (on server side). Misplaced icons might be due to the host system - what client did you use on what platform?
nxagent was running on the server.

responsitivity is less than with a clean X session. There are bound
to be tradeoffs, of course.

As all graphics are cached, menues tend to respond retarded at first click but pop up in no time at any further usage.
From what I understand, the protocol used is diffed pngs, which
explain why things look a bit strange.

You can also switch to jpeg - and here select the quality (depending on your bandwidth). True X widgets are transmitted lossless as they are taken from local libraries - if however you run java applets or even with mozilla, high compression results in jpeg typical artefacts. You won't notice those if you perform nx on a beamer.

I haven't played too much with it yet, just switched to different compression levels. Obviously the settings need to be tweaked.

The load on the server when showing graphics intensive apps like
flash is about the same with and without nx. In other apps it's

This issue is really the one I know least of. Does an NX server need similar power as an ltsp server? Or even more as compression takes its overhead? As soon as you open your NX server to ordinary users, it is advisable to run freeNX on a machine different from your LTSP to avoid performance outages during classes.
The setup was a Sarge based server with LTSP 4.1, packages for NX

Ah, tell us: you integrated nx in LTSP4 (as documented?) We couldn't test this one, because our woody LTSP3 is not that flexible.

Yes, well not I, someone else in the LTSP team. You can find the package here:


There is a README in the tarball, just follow that. The stuff that goes into the LTSP tree is built in the LBE, so you will need LTSP 4.1 for it to work. No reason it would not work with LTSP3, just go ahead and make a package.

For the server side I used the mirror I found at http://www.ubuntuforums.org/showthread.php?t=1968

deb http://kanotix.com/files/debian/ ./

apt-get update; apt-get install freenx; nxsetup

was all I needed to do.

client built in LBE, and a Sarge package for freenx server side as
shown on the Ubuntu web site. It was a breeze to make work, but a few

Ah, could you point us to the URL? I made a howto to install nx with Woody based Skolelinux on skolelinux.org/de...

rough edges during the login process.

Does it use less bandwidth? Definitely.
Is it useful? Perhaps. Not definitely.

Is it more secure: yes, everything runs in ssh - so passwords are not transmitted any longer internally.
True, that too. Pity the display manager is English only, but I guess that would be easily fixed once someone got round to translating it.

For me it is mainly interesting to allow teachers remote access from home. Schools that have only 10Mbit networks (say in LDCs) can yet run LTSP servers with nx.

It is very interesting to reduce bandwidth usage in a standard thin client installation too.

Just my 15 öre (is this 2 cent?)

Heh, it's slightly more than 2 cents :)

Med vennlig hilsen
Ragnar Wisløff
life is a reach. then you gybe.

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