SSH Compression

Jeff jeff at
Mon Aug 29 10:10:06 UTC 2011

Thanks for the input, David.

Still getting my head around *NX. Can the client work from the thin- 
clients without loading a windowing system?

In the meantime, I found this article 
  about compression.

Looking around the configuration files I don't see any compression  
enabled in /var/lib/tftpboot/ltsp/i386/lts.conf so I've added:

## SSH compression between LTSP client and server

remotely, but haven't been onsite to test it yet.

/var/lib/tftpboot/ltsp/i386/config-2.6.38-8-generic has several  
compression parameters, but nothing explicitly about SSH from what I  
can see.

Will post an update when I've had a chance to test.



On 24 Aug 2011, at 3:24 PM, David Groos wrote:

> Hey Jeff, Sounds like you are looking for good gui remote access  
> over ssh? I use FreeNX as the server and use NoMachine's client and  
> now also use OpenNX since it works well with lion-10.7.  The access  
> over broadband internet is just like sitting at the computer--works  
> great to manage remote servers running Edubuntu/ltsp.  I hear it is  
> even a decent experience over dial-up.  So, while I don't know what  
> the compression is, it must be pretty good to work this well in this  
> situation.  If you have more questions, let me know.
> David
> On Wed, Aug 24, 2011 at 7:15 AM, Jeff <jeff at> wrote:
> Hi all,
> I don't have easy access to a server at the minute, and not sure  
> where the settings are anyway; but I've been wondering about this  
> for a while and am just hoping that someone can point me in the  
> right direction:
> A week or so ago when I was onsite at a school, I ran a binary  
> tcpdump to get an indication of network usage with approximately 12  
> thin clients working.
> It wasn't a very precisely measured test or anything, but the server  
> sent/received a Gigabyte of traffic in about a couple of minutes.
> So I'm just wondering whether SSH compression is enabled by default  
> or not? And if it is, whether there's any way to tweak it?
> Also, it occurs to me that SSH compression would have to be  
> lossless, by nature. So I'm wondering if there's any way to get  
> something like tight-vnc working; or whether we should try a  
> lightweight X desktop like XFCE?
> I'm not really happy about the performance, compared to terminal  
> server, for ex, or even the old Fedora/Gnome K12-LTSP we upgraded  
> from.
> Insights and pointers appreciated. Flames > /dev/null
> ;-)
> --
> Jeff Brown
> Tel:+27-74-101 5170
> Fax:+27-86-532 3508

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