Relatively Simple Remote Assistance over VNC

I was looking for a simple way of providing remote assistance to someone on a Linux machine, in this particular instance Ubuntu, and here is what I've come up with.

The first step is to make sure that you have ssh access to the machine in question. There's heaps of tutorials on the web for this, but the easiest way is to just install the openssh-server

# apt-get install openssh-server

and edit the config file /etc/ssh/sshd_config. You might need to change the port to prevent it being blocked by ISP's and switch off root logins. Don't forget to fix your firewall rules to allow access as well.

You'll also need some way of actually finding the box on the net, so set up something like DynDNS so that you can easily find the box on the web. ddclient is a good client to dynamically update, and if on dial-up you can set it so that it triggers whenever a connection is made. It's probably a good idea to make sure all the SSH side of things are working now, as the rest can be done remotely via SSH.

The idea of providing remote assistance is to allow both users access at the same time, so in order to do this we'll use x11vnc. So on the machine you want to provide assistance to,

# apt-get install x11vnc

Finally, on your machine, make sure you have the vncviewer installed,

# apt-get install xvncviewer

Once this is done, it's time to start assisting by running

ssh -L 5900:localhost:5900 user@hostname 'x11vnc -localhost -display :0'

making sure to replace user and hostname appropriately. If you changed the port SSH is working on earlier, you might also need the -p port option.

Then, run

xvncviewer localhost

and you should get a display of what the other person sees.