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I am using ssh -X to display GUI apps locally.
Is there a better way to speedup this processes - something similar what NoMachine Nx server / client does?

Thanks, Mariusz.

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  • Hi, thx for the answers. The problem is that I do not have root access on that system and there is no X server running. Therefor I use ssh -X to forward GUI applications to my X server running locally on my workstation. I am fan of NX but I think it will not help in this situation while it needs NX server running remotly?
    – user20196
    Dec 5, 2009 at 11:27
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    Actually, you run the X server on YOUR system, the remote machine runs an X client. This is admittedly almost certainly different terminology than you would expect. Dec 5, 2009 at 15:46
  • I found article how to solve this. "How to forward display of any X application to the NX session" nomachine.com/ar/view.php?ar_id=AR01F00498
    – user20196
    Dec 6, 2009 at 12:19

4 Answers 4

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If you add the -C option to ssh, you'll compress the data prior to encrypting it. Depending on the speed of your connection and, I suppose, on the speed of your CPU, this can make a difference. Back in the old days of dial-up modems, it made a huge difference, and I've seen it make a measurable difference on cable modems running VMWare Workstation from a remote X client. Your mileage may vary.

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  • Thx for the hint with the -C. Actually I am using it all the time. I does not make big difference. I think it has to do something that NX sends a lot of very tiny packets which makes that your application runs smoothly. That's what I would like to achieve without need to install nx server remotly (I do not have root access there and there is no X server installed).
    – user20196
    Dec 5, 2009 at 11:29
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    Use something like ssh -c arcfour,blowfish-cbc -XC, as the AES encryption is the main culprit.
    – leoluk
    Jun 23, 2012 at 9:54
  • Huh, in 2017 -C has a huge impact on even modest modern CPUs. AES is handled by hardware these days too and things like arcfour and blowfish are removed because they're so insecure. Great answer.
    – Oli
    Apr 20, 2017 at 8:56
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Why not use NX? I found it pretty easy to set up, and it's much faster than either direct X11 connections or VNC. Plus it has the advantage that you can disconnect and reconnect to the apps later without killing them. It's free for noncommercial use, and not that hard to set up on standard linux OS's.

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You don't need to SSH, of course. You can configure your X Server to accept connection via TCP from other remotes to display their apps on your display. Of course this is insecure due to the fact that SSH is not involved, but it would be a bit faster due to the lack of encryption. The amount of data being passed, however, is the real performance killer.

As for alternatives to NoMachine's NX Server, there is FreeNx and NeatX. I use NeatX with NoMachine's client, which works pretty well, even over VPN. These solutions compress the streams improving the performance quite a bit.

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I would recommend looking into Xpra. I just started using it and it has been orders of magnitude faster than X11 forwarding even over my Gigabit Ethernet network.

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