Internal licensing error

What do you say? Is there something wrong with the internal license? Well, just change the name of that client, and we’ll be alright!

Welcome to the world of connecting an Ubuntu computer to a Windows Server. The later years this has become quite easy, but this summer the University of Oslo has upgraded its servers. And with a new version of Windows, there is bound to be new problems on the way.

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Automount an SSH server in Ubuntu

If you ever need to mount an SSH server in Ubuntu, this is probably the easiest way to do it. This method uses a public/private key pair to authenticate with the server, making the whole process work without passwords.

If you don’t  have SSH available to host, but you’ve got a Windows shared directory, I suggest you have a look at a tutorial I’ve written earlier on that topic.

Generating a key pair

You are probably used to connect to your SSH host using a login and a password. This might seem secure, but there is actually another way which is much more convenient, and much more secure. That way is the way of a public/private key pair. If it sounds a bit advanced I will give you a short explanation in a moment, but first you should know that you are not to worry about doing this. It’s quite easy to set up an SSH key pair in Ubuntu.

A private/public key pair has a pretty easy way of functioning. First of all, you should know that the “keys” we are talking about are two small files. They contain a long text which makes up the two keys. These two keys are used to encrypt and decrypt other messages. For instance the data sent back and forth to your SSH host.

The amazing part with these keys, are that they are the only keys which can decrypt whatever message was encrypted with the other key. This makes sure that the server is the only computer able to read your messages, and that your computer is the only which might read the server’s messages. A huge problem with sending passwords over the Internet is the fact that even though the password was encrypted, it might get picked up by someone else who’s sniffing on your wireless connection. That way it might be reused in the encrypted form to log back in on the server. SSH is a bit more sophisticated by encrypting the password differently every time, but essentially it follows a pattern which is easily decrypted.

With a key pair the connection is way more secure, and in short terms it works like this:

  1. Your computer connects to your host
  2. The server sends back a message, for instance “hi!”, encrypted with your public key
  3. Your computer decrypts the message with your private key, reads it as “hi!”, and encrypts it again
  4. The server recieves your encrypted message, decrypts it with the public key, and checks that the message is the same as when it was sent out. You are now logged in.

This way the server knows that you are who you say you are for two reasons: You are the only one who could decrypt the message with your key, and you are the only one who could encrypt the message again so that it could be decrypted by the server.

The reason we call them private and public keys are pretty obvious. The private key should be kept private so that nobody else may pretend they are you, but the public key may be spread around (thereby ‘public’) since it is useless for anything but encrypting messages for you.

Enough with the theory, get to the tutorial already!

To generate a key pair in Ubuntu, go to Applications > Accessories > Passwords and Encryption keys. A window like this should show up:

Screenshot-Passwords and Encryption KeysClick File > New…

Screenshot-Create New ...Choose Secure Shell Key and click Continue.

Screenshot-New Secure Shell KeyType in your e-mail address and click Create and Set Up.

Screenshot-Passphrase for New Secure Shell KeyAdd a passphrase for the key. This might be anything you’d like. It just makes the key a bit more secure.

Screenshot-Set Up Computer for SSH ConnectionNow, type in the address of your host and your username and click Set Up.

You will be prompted for your SSH password. Type this in and click OK.

Ubuntu will now take care of the rest for you, and you should be able to connect to the server without any hassle.

So, how do we mount it automatically?

After you have generated your keypair, you just go to System > Preferences > Startup Applications and add the following command:

sshfs username@server.example.com: /home/username/myssh

That is how easy it is. If you, like me, are using a server which formats the folder names with norwegian characters, you might want to add

-o modules=iconv,from_code=ISO-8859-1

to the end of the command, making the whole command look like:

sshfs username@server.example.com: /home/username/myssh -o modules=iconv,from_code=ISO-8859-1

Mounting a Windows share folder in Ubuntu

I have been connecting to my home folder at the Universitiy of Oslo for quite some time now, and since they use the Windows file-sharing protocol for this purpose, there has been room for quite som headaches.

After some googling I was able to figure out how to connect and mount a folder temporarily, but I had to re-mount it with my password every time I rebooted the computer. Finally, after realizing I actually tried this when I first figured the temporary method, I am now able to mount it permanently. I’ll show you how, in just a few, simple steps:

First of all, we need to install the samba file system. Type the following in to a terminal:

sudo apt-get install smbfs

Next, we need to get our username and password ready. Type the following into a terminal while replacing [your username] with your username:

gksudo gedit /home/[your username]/.smbcredentials

In the new file, add the following while using your own username and password:

username=[your username on the windows (smb) server]
password=[your password on the windows (smb) server]

Close the file, and type the following in to your terminal:

sudo mkdir /media/sambamount
sudo cp /etc/fstab /etc/fstab.backup
sudo gedit /etc/fstab

We have now made a backup of the current fstab (the file managing your mounted file systems) and opened it for editing. Add the following line to the file while substituting the brackets with your own values:

//[server name or DNS]/[folder on server to mount] /media/sambamount cifs credentials=/home/svenni/.smbcredentials,uid=[your local username],gid=users,iocharset=utf8 0 0

Save and close the file.

Everything should now be ready for the directory to be mounted when you boot the computer, but you could test it before you have to close the browser and take a two minute break away from your precious desktop.

Type the following into your terminal to test the mount:

sudo mount -a

Your shared windows directory should now appear on the desktop as a hard drive icon with the name «sambamount».