This is the second part in a four part series covering remote access to Linux machines using SSH.

• Part 1 – Installing and configuring SSH
• Part 2 – Securing SSH and opening up to the outside world
• Part 3 – Graphical connections
• Part 4 – Accessing your machine from Windows

Everything in this tutorial should apply to most Linux distributions, however some of the commands may be specific to Ubuntu. You may need to modify some commands to work with your Linux distribution. This is an advanced tutorial, so most instructions will be given as text commands.

A Note About Security

Allowing outside machines to access your computer is inherently risky. Assuming your router and/or firewall is properly configured, you will need to poke some holes in it. This potentially leaves you vulnerable to attack. Proceed at your own risk. Because security is a constantly changing issue, you are responsible for securing your own computer and network. You have been warned. If you are not behind a router or other physical firewall and you can’t explain why this is the case, do not proceed.

Introduction

You’ll be glad to know that the graphical piece is actually a lot easier than the first two parts. It’s really just a few configuration changes and that’s it.

On the server end

Open your /etc/ssh/sshd_config file.

gksudo gedit /etc/ssh/sshd_config

Then make sure that X11Forwarding is set to on and both of the lines below are uncommented (meaning that they do not have a # in front on them:

X11Forwarding yes
X11DisplayOffset 10

That’s it on the server end!

On whatever computer your using….

You may also need to change some settings on the computer from which you are connecting. Open your /etc/ssh/ssh_config file. Notice the subtle difference between sshd_config and ssh_config.

gksudo gedit /etc/ssh/ssh_config

Then you need to make sure that these lines are uncommented:

ForwardAgent yes
ForwardX11 yes
ForwardX11Trusted yes

Trying it out…

Now try connecting again:

ssh -X -p <em>port number</em> <em>username</em>@<em>dyndns username</em>.dyndns.com

Then just type the name of a graphical application:

gnomine

Just take a moment to think about how cool it is that you’re running Gnome Mines graphically across the internet from a different computer.

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