[SATLUG] Ubuntu 10.04 Remote Desktop

Borries Demeler demeler at biochem.uthscsa.edu
Thu Jan 6 22:22:56 CST 2011

> I want to access my computer from any of the other household computers 
> on the local net: one ea. Mac, Linux Eee, and a Puppy box.  Preferences 
>  > Remote Desktop make it look easy. However, I have not been able to 
> make it work.  I've made an effort at self help.  If anything, there is 
> too much info. on line; I haven't been able to sort it out.
> It was suggested that I use ssh.  I found I needed Openssh and used 
> Synaptic Pkg Mgr to install Openssh client and server.  Still, no luck.  
> My first try with Puppy gave the following, which is typical:
> # ssh izzy.local
> The authenticity of host 'izzy.local (' can't be established.
> RSA key fingerprint is 7c:c2:cc:3a:fe:18:bd:20:f7:29:80:1b:e8:42:5a:b1.
> Are you sure you want to continue connecting (yes/no)? yes
> Warning: Permanently added 'izzy.local,' (RSA) to the list of 
> known hosts.
> root at izzy.local's password:
> Permission denied, please try again.
> root at izzy.local's password:
> Permission denied, please try again.
> root at izzy.local's password:
> Permission denied (publickey,password).
> #
> No matter what, the password is ignored.
> It appears that the secret may be in /etc/ssh/sshd_config.  I don't want 
> to mess with a public key, so I changed "Pubkey Authentication" from yes 
> to no. That made no difference.  But, sshd_config is a big file with a 
> lot I don't understand, so it seems time to seek help.
> *Maybe all I need is the command to connect w/o using ssh.
> *
> Any help will be appreciated.  I've already put too much time into this 
> project.
> Thanks,
> Andy Pickens
> "Sometimes the magic works, sometimes it doesn't."


if 'izzy' is an ubuntu machine I suspect it is not possible to log in as
the root user. You may want to try logging in as a regular user:

ssh regular_user at izzy.local

Another issue is that ssh will not give you the entire desktop, but it can
transport X. So if you want to run an X application on the remote machine,
connect with:

 ssh -X regular_user at izzy.local

To compress over the network for speedier interface, use the -C flag:

 ssh -XC regular_user at izzy.local

Then, once logged in, you should be able to run any X app from the command line
and it will pop up on your local machine. In order to use 'ssh -X' you need to
make sure that sshd on izzy.local is configured to forward X11 data. There is
an entry in your sshd_config, it is called X11Forwarding, which should be set to "yes".

As is usual in Linux, there are many ways to skin this cat. If your local machine is 
a Linux/X11 capable machine, and you are running an Xserver, you could just allow 
izzy to write to your current display, on the local computer, issue:

xhost + izzy.local

on izzy, after ssh into it, issue:

export DISPLAY mylocalhost:0 (where :0 is your display, if you are not on :0, enter the 
correct display). Then you can execute any desired X application on izzy and it will
show up on your local X11 display.

Finally, you could use an application like vnc. It requires a server on the remote
box (izzy, in this case), usually called vncserver or Xvnc. On the local host you
would run vncviewer izzy.local:n where n is the display number, and each vnc instance
has its own display. The vnc way is nice because it allows you to see the entire desktop,
not just the X11 application, and you can control which X11 window manager you want
to use. The other nice thing about vnc is that you don't need a local X11 server,
which means you could get a Linux desktop from izzy on your local windows machine.

Now go and try some of these suggestions and send back any questions.

Cheers, -borries.

P.S. you do not need to install any public keys to use ssh. If you
exchange public keys you can make password free logins possible. That's
the next step, but it is unrelated to your wish to export the X11 display
to a remote computer.

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