Optimizing SSH for low speed links

Ian McCulloch ianmcc at lorentz.leidenuniv.nl
Thu Aug 8 11:28:46 EST 2002

On Thu, 8 Aug 2002, Barndon Daron wrote:

> Guys,
> Hope this is not considered OT but a linux box will be on one end! (solaris on the other) :-)
> I have been asked to help with a project to get SCP (or ftp - I prefer ssh if possible) running across a 2400baud radio link (with PPP to a cisco router). Is there anyway to optimize SSH for this? This will be used to transfer files from remote monitoring stations...
> SSH works across this link but is _VERY_ slow...
> Hope someone can help me!
> Thanks
> Daron

Are you already using some form of compression?  If not, ry -C switch to 

I have noticed that initiating an ssh connection on a slow link can take a 
long time, I guess it depends on which authentication method you use 
because there are a lot of possibilities and a lot of packets pass back 
and forth as ssh determines what is going on.  Try -v (multiple times) to 
see exactly what is happening.  I don't know what to do to try to optimize 
this however.

Ian McCulloch

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