D3 Tips and Tricks v4

Friday, 9 January 2015

Setting up remote access via SSH on a Raspberry Pi

The following post is a section of the book 'Raspberry Pi: Measure, Record, Explore'.  The entire book can be downloaded in pdf format for free from Leanpub or you can read it online here.
Since this post is a snapshot in time. I recommend that you download a copy of the book which is updated frequently to improve and expand the content.

Remote access via SSH

(This post follows on from the demonstration of setting up remote access of the GUI on our Raspberry Pi in the previous post.)
Secure Shell (SSH) is a network protocol that allows secure data communication, remote command-line login, remote command execution, and other secure network services between two networked computers. It connects, via a secure channel over an insecure network, a server and a client running SSH server and SSH client programs, respectively (there’s the client-server model again).
In our case the SSH program on the server is running sshd and on the Windows machine we will use a program called ‘PuTTY’.
This is definitely one of the easiest set-up steps since SSH is already installed on Raspbian.
To check that it is there and working type the following from the command line;
/etc/init.d/ssh status
The Pi should respond with the message that the program sshd is running.
sshd Running
You only need to carry out this step if SSH is not installed.
If for some reason SSH is not installed on your Pi, you can easily install with the command;
sudo apt-get install ssh
Once this has been done SSH will start automatically when the Raspberry Pi boots up.
The client software we will use is called ‘Putty’. It is open source and available for download from here.
On the download page there are a range of options available for use. The best option for us is most likely under the ‘For Windows on Intel x86’ heading and we should just download the ‘putty.exe’ program.
Save the file somewhere logical as it is a stand-alone program that will run when you double click on it (you can make life easier by placing a short-cut on the desktop).
Once we have the file saved, run the program by double clicking on it and it will start without problem.
The first thing we will set-up for our connection is the way that the program recognises how the mouse works. In the ‘Window’ Category on the left of the PuTTY Configuration box, click on the ‘Selection’ option. On this page we want to change the ‘Action of mouse’ option from the default of ‘Compromise (Middle extends, Right paste)’ to ‘Windows (Middle extends, Right brings up menu)’. This keeps the standard Windows mouse actions the same when you use PuTTY.
PuTTY Selection Set-up
Now select the ‘Session’ Category on the left hand menu. Here we want to enter our static IP address that we set up earlier ( in the example that we have been following, but use your one) and because we would like to access this connection on a frequent basis we can enter a name for it as a saved session (In the scree-shot below it is imaginatively called ‘Raspberry Pi’). Then click on ‘Save’.
PuTTY Session Set-up
Now we can select our raspberry Pi Session (per the screen-shot above) and click on the ‘Open’ button.
The first thing you will be greeted with is a window asking if you trust the host that you’re trying to connect to.
PuTTY Session Connection
In this case it is a pretty safe bet to click on the ‘Yes’ button to confirm that we know and trust the connection.
Once this is done, a new terminal window will be shown with a prompt to login as: . Here we can enter our user name (‘pi’) and then our password (if it’s still the default it is ‘raspberry’).
PuTTY Session Connected
There you have it. A command line connection via SSH. Well done.
As I mentioned at the end of the section on remotely accessing the Raspberry Pi’s GUI, if this is the first time that you’ve done something like this it can be a very liberating feeling. To complete the feeling of freedom let’s set up a wireless network connection.

The post above (and heaps of other stuff) is in the book 'Raspberry Pi: Measure, Record, Explore' that can be downloaded for free (or donate if you really want to :-)).

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