Help Desk Screeds

For years, Ubuntu (and most Debian based Linux distributions) have relied on a program called Synaptic Package Manager to install software. However, as of Ubuntu 11.10 Oneiric Ocelot, Synaptic has been removed from Ubuntu in favor of the Ubuntu Software Center. Ubuntu Software Center does have a nicer GUI than Synaptic. However, if you prefer Synaptic, it’s quite easy to install on Ubuntu 13.04 Raring Ringtail. Synaptic can especially come in handy as you set up a new Ubuntu installation, since you can use it to search for specific packages that you might need.

To install Synaptic on Ubuntu, go to the Terminal (to find the Terminal, click on the Dash and search for Terminal) and type this command:

sudo apt-get install synaptic

Enter your password to authenticate, and apt-get will download and install Synaptic for you.

After the installation is complete, you can launch Synaptic by searching for “Synaptic” in the Dash and click on the program’s icon. You’ll need to enter your password for authentication before Synaptic launches.

-JM

ADDITIONAL READING:

The Ubuntu Beginner’s Guide

The Ubuntu Desktop Beginner’s Guide.

Ubuntu 13.04 Raring Ringtail comes with the visually impressive Unity desktop environment, but Unity does take a moderate degree of graphical horsepower. If you’re using Ubuntu on an older computer, you might want to install the GNOME Fallback environment, formerly known as the GNOME Classic environment. GNOME Fallback is less demanding of your computer’s graphical capabilities, which may speed up Ubuntu’s performance quite a bit.

To install GNOME Fallback, go to a Terminal window (if you don’t know how to find Terminal, go to the Dash, the Ubuntu button in the upper-left hand corner of your screen, and search for “Terminal”) and type this command:

sudo apt-get install gnome-session-fallback

enter your password to authenticate, and apt-get will download and install GNOME Fallback for you.

After the installation is complete, restart your computer.

When the Ubuntu logon screen returns, click on the small icon of the Ubuntu logo next to the list of user accounts. This will list a menu of various desktop shells installed on your computer, and GNOME Fallback with No Effects should be at the top of the list. Select GNOME Fallback, and you’ll log into the classic GNOME environment.

If you want to switch back to Unity, log back out, and select a different desktop environment from the list.

-JM

ADDITIONAL READING:

The Ubuntu Beginner’s Guide

The Ubuntu Desktop Beginner’s Guide.

Ubuntu 13.04 Raring Ringtail comes with the Unity interface, which is a slick, modern desktop interface. However, Unity seems to inspire a “love it or hate it” reaction. Quite a few people prefer GNOME 3, and its GNOME Shell interface. In previous versions of Ubuntu, it was difficult, if not impossible, to successfully install GNOME Shell on Ubuntu. In the current version of Ubuntu, however, it’s quite easy.

To install GNOME Shell, go to a Terminal window (if you don’t know how to find Terminal, go to the Dash, the Ubuntu button in the upper-left hand corner of your screen, and search for “Terminal”) and type this command:

udo apt-get install gnome-shell

Enter your password to authenticate, and apt-get will download and install GNOME Shell for you. It will need to download about 75 megabytes worth of data, so depending on your connection speed, the installation may take some time.

After the installation is complete, restart your computer.

When the Ubuntu logon screen returns, click on the small icon of the Ubuntu logo next to the list of user accounts. This will list a menu of various desktop shells installed on your computer, and GNOME should be at the top of the list. Select GNOME, and you’ll log into GNOME Shell.

If you want to switch back to Unity, log back out, and select a different desktop environment from the list.

-JM

ADDITIONAL READING:

The Ubuntu Beginner’s Guide

The Ubuntu Desktop Beginner’s Guide.

One of the most common uses of a Ubuntu 13.04 Raring Ringtail machine – whether a server or a desktop – is to share files across the network. If you’re not familiar with the term, “file sharing” means to make a folder on your system available to clients on the network. From their own machines, users are able to access your shared folder from their computers, and depending upon how you’ve configured the security, they can copy the files for themselves, alter the files, add new files, or even delete files.

There are a number of different programs that offer file-sharing capabilities. Most Ubuntu 12.10 Quantal Quetzal systems use the “Samba” software, since it is can easily share files with Windows-based computers. It’s common to find organizations that have a number of users with Windows systems storing their data on a Linux server running Samba.

In this post we’ll show you how to set up a basic Samba server, and how to access those shares from client computers, on a Ubuntu machine.

Samba has a vast array of options and configuration settings, but here we’ll show you how to set up and configure a basic Samba server with one user.

First, you’ll need to install Samba. Make your way to a command prompt and type this command:

sudo apt-get install samba

Enter your password to authenticate, and apt will download and install Samba and its attendant utilities for you.

It’s important to realize about Samba is that it stores its own set of user accounts, separate from the main accounts, in the /etc/samba/smbpasswd file. That means you’ll need to create a separate Samba password for every user you want to access your file shares. You create this password using the smbpasswd command. For example, to create a command for a user named camalas, here’s how the command should look:

sudo smbpasswd -a camalas

Be sure to give camalas’s Samba account an appropriately strong password (make sure it includes uppercase, lowercase, punctuation, and numbers). Once camalas’s password is created, the next step is to create a directory for her to share. Begin by creating a folder named ‘test’ in camalas’s folder, which we’ll use for our first shared folder:

mkdir /home/camalas/test

(NOTE: DO NOT use sudo to create the folder, because then the owning user and group will be set as ‘root’, which means you won’t be able to access the folder using your Samba username and password.)

The next step is to edit the /etc/samba/smb.conf file, the main configuration file for Samba. As always, make a safe backup copy of the original smb.conf file to your home folder, in case you make an error:

sudo cp /etc/samba/smb.conf ~

Now use vi to edit the /etc/samba/smb.conf file:

sudo vi /etc/samba/smb.conf

The smb.conf file is long and rather complex, but for the purposes of this demonstration, you can ignore most of it. Key down to the very end of the file and insert this text:

[test]

path = /home/camalas/test

available = yes

valid users = camalas

read only = no

browsable = yes

public = yes

writable = yes

(There should be no spaces between the lines, and note also that there should be a single space both before and after each of the equal signs.)

Here’s what some of the more important configuration options mean.

-The “[test]” gives the name of the file share.

-The “path” option specifies the location of the folder to be shared.

-The “available” option specifies that the file share is available to clients on the network.

-The “valid users” option details the users that are allowed to access the file share. In this case, we’ve set it so that only the camalas account can access it. You can add additional accounts here, if you prefer.

-The “read only” options specifies whether nor not clients will be allowed to write to the file share.

-The “writable” option specifies that data can be written to the file share.

The settings specified above will share the test folder we created earlier, and give your username and your username alone permission to read and write to the folder. Once you have input the changes, save smb.conf, exit vi, and restart Samba with this command:

sudo restart smbd

(This will force Samba to restart, re-reading its configuration files and activating the share you just created.)

Once Samba has restarted, use this command to check your smb.conf for any syntax errors:

sudo testparm

If you pass the testparm command, Samba should be working. Try accessing the share from another client on your LAN.

-JM

ADDITIONAL READING:

The Ubuntu Beginner’s Guide

The Ubuntu Desktop Beginner’s Guide.

Here’s how to install Google’s lightweight Chrome browser on Ubuntu 13.04 Raring Ringtail. It’s a bit trickier than in previous versions of Ubuntu, since some of the dependencies Chrome uses have been removed from the latest version of Ubuntu.

First, you’ll need to download and install libudev0, the missing dependency. You can get it at the launchpadlibrarian website:

i386: http://launchpadlibrarian.net/132294322/libudev0_175-0ubuntu19_i386.deb
amd64: http://launchpadlibrarian.net/13229415/libudev0_175-0ubuntu19_amd64.deb

If you have a 32-bit version of Ubuntu, get the i386 version, and if you have the 64-bit version, download the amd64 version of libudev0.

Once the download is complete, you’ll have a *.deb installer package for libudev0in your Downloads folder. Double-click on it to launch the installer. You’ll be taken to the Ubuntu Software Center. Click on the Install button to begin the installation.

You’ll need to enter your password to authenticate, and then follow the default prompts to install libudev0.

Next, visit the Google Chrome website:

http://www.google.com/chrome

Click on the Get Google Chrome button, which will take you to the download page. As with libudev0, select the 32-bit or the 64-bit version for Ubuntu, depending upon your system’s processor architecture. Hit the accept and install button, and the Chrome installer will download.

Once the download is complete, you’ll have a *.deb installer package for Chrome in your Downloads folder. Double-click on it to launch the installer. You’ll be taken to the Ubuntu Software Center. Click on the Install button to begin the installation of Chrome.

You’ll need to enter your password to authenticate, and then follow the default prompts to install Chrome.

After the installation is complete, you can launch Chrome by clicking on the Dash (the Ubuntu icon on the upper-left hand corner of your screen), searching for Chrome, and clicking on the Chrome icon.

-JM

The Ubuntu Beginner’s Guide

The Ubuntu Desktop Beginner’s Guide.

SSH stands for “secure shell”, and it is a network protocol that allows you to securely send commands to a remote machine. The “secure” part comes from the fact that the connection is encrypted, which means that an attacker cannot eavesdrop on the connection, or intercept and replace your commands with his own midway through transit. SSH is pretty reliable and secure, and is commonly used in the Linux world. Administrators often use it to remotely manage machines – it’s usually more comfortable to control a server from your laptop than in the chilly and noisy server room.

In this post, we’ll show you how to set up an SSH server on Ubuntu 13.04 Raring Ringtail.

The default SSH server package for Ubuntu is OpenSSH Server, which we’ll use here.

First, you’ll need to install OpenSSH Server. To do so, open up a Terminal window and type the following command:

sudo apt-get install openssh-server

Enter your password to authenticate, and the apt utility will download and install OpenSSH Server for you. Depending on the speed of your Internet connection and your computer, the installation may take several minutes.

Once the installation has finished, return to the Terminal window. We’ll need to make a few changes to your /etc/ssh/sshd_config file in order to increase SSH’s security. First, as always, we’ll want to make a backup copy of your sshd_config file in case anything goes wrong. Type this command into the Terminal:

sudo cp /etc/ssh/sshd_config ~

This will make a backup copy of the sshd_config file in your home directory.

Next, we’ll need to edit the sshd_config file itself.

sudo vi /etc/ssh/sshd_config

(Note that you can use emacs or gedit or another text editor of your choice.)

Like almost every other server software package, SSH is controlled by a number of directives in its configuration file. The default installation of OpenSSH server is reasonably secure. However, you might want to make a few changes to tighten up its security to additional degree.

The “PermitRootLogin” directive is one you’ll want to change. Once you’re editing the /etc/ssh/sshd_config file, you’ll want to change the following directive as follows:

PermitRootLogin no

This will keep anyone from attempting to log into your server via SSH as root. It’s generally a good idea not to allow any to log into your SSH server as root. If an attacker manages to hack into your SSH server with the root login, he will have complete control over your machine, and that is definitely not a good thing.

Another directive you might want to change is the “AllowUsers.” When the AllowUsers directive is active, only users specifically specified in the directive can access the system through SSH. This adds an additional layer of protection to your SSH server by only allowing specific users to connect via SSH. For instance, if you wanted to limit SSH access to just the “camalas” user account, edit the AllowUsers directive like this:

AllowUsers camalas

To add multiple users to the AllowUsers directive, just add them one by one without commas or semicolons. An AllowUsers directive that permits the camalas user account and the lmaraeus user account to log in would look like this:

AllowUsers camalas lmaraeus

You may also want to consider changing the Port directive. By default SSH runs over TCP/IP port 22, which means that any malware bot autoscanning port 22 can target it. If you set up your user accounts with a weak password (always a bad idea), eventually an automated bot might break through and guess the password. Changing the Port directive to something different will make SSH run over a different port, blocking some of those automated cracking attempts. To set SSH to run over port 5699 instead, make sure your Port directive looks like this:

Port 5699

Note that if you change your SSH server’s default port, you’ll need to remember the new port number when using an SSH client, which we’ll cover in the next section.

After you’ve finished changing the directives in /etc/ssh/sshd_config, switch vi to command mode, and save and quit vi. After you return to the command line, restart the SSH daemon with this command:

sudo restart ssh

You should now be able to SSH into your Ubuntu machine from another system with an SSH client.

-JM

ADDITIONAL READING:

The Ubuntu Beginner’s Guide

The Ubuntu Desktop Beginner’s Guide.

In order to help fund Ubuntu’s continued development, Canonical has added Amazon search results to the Dash via the Dash’s new “Shopping Lens”. The idea is that if you see an interesting product in the Dash search results and buy it, Canonical gets a share of the profits. This is not too different from the arrangements used by many popular websites to make money via the Amazon Affiliates program. However, if you have privacy concerns about the search results, they are simple enough to remove.

To remove the Amazon search results from the Dash, go to the Terminal (click on the Dash and search for “terminal” to get to it, or hit CTRL+ALT+T), and then enter this command:

sudo apt-get remove unity-lens-shopping

Enter your password to authenticate, and apt-get will uninstall Unity’s shopping lens. After you log out and log back into your Ubuntu system, the Dash will not longer display Amazon search results.

-JM

ADDITIONAL READING:

The Ubuntu Beginner’s Guide

The Ubuntu Desktop Beginner’s Guide.

In this post, we’re going to explain how to use your Ubuntu 12.04 Precise Pangolin machine both as a VNC server and as a client. VNC is an extremely useful networking protocol that allows you to remotely control a machine as if you were sitting in front of it and using its keyboard and mouse. We’ll show you how to configure your Ubuntu machine as a VNC server, and how to use Ubuntu to connect to other computers acting as VNC servers.

WHAT IS VNC?

The acronym “VNC” stands for “Virtual Network Computing”, and allows a computer with a VNC server to transmit its keyboard, mouse, and monitor information to a remote computer. This essentially allows the remote computer to control the server computer. VNC technology was originally developed by the Oracle corporation in the 1990s, and the technology was later purchased by AT&T. A variety of different VNC implementations have been developed for every operating system, and this means a VNC client on, say, a Windows computer can control a VNC server on a Ubuntu system.

SECURITY LIMITATIONS

Note that by default, the version of VNC included with Ubuntu does not encrypt the connection, so that means anyone listening in on your network can in theory see everything you do on the remote computer. So it’s best only to use Ubuntu’s VNC implementation on a local network, and on a computer that does not have high security needs.

With those limitations in mind, let’s discuss how to set up Ubuntu as a VNC server.

VNC SERVER

To access Ubuntu’s VNC server capabilities, click on the Dash (the Ubuntu icon in the upper left-hand corner of your screen) and type “Desktop Sharing” into the search box:

Click on the icon, and Desktop Sharing, the utility that controls Ubuntu’s VNC server, will then launch:

The Desktop Sharing utility offers a variety of options to customize the security and operating of Ubuntu’s VNC server. We’ll go through these options one by one.

The first option, “Allow other users to view your desktop”, allows other users to view your desktop via a VNC client. However, in order to actual control your desktop, you need to check the “Allow other users to control your desktop” checkbox. Allowing other users to view, but not control, your desktop is useful in situations where you want other people to view your desktop without having the ability to affect your computer. For example, if you are running a presentation off your Ubuntu computer, this would allow you to share the presentation without letting the other users control your computer.

The next three options deal with security. The first, “You must confirm each access to this machine”, means that every time someone tries to connect to your Ubuntu machine via VNC, you’ll get a little pop-up box that looks like this:

This allows you to refuse or allow VNC connections to your computer.

The next option lets you set an additional password to grant access to your computer via VNC. This adds an additional layer of security to your computer, since you can grant VNC access only to users to whom you have given the VNC password. Additionally, if you decide to revoke VNC access to your machine, you can do so by the simple method of changing your VNC password.

The final option, “Automatically configure UpnP router to open and forward ports”, lets you configure the VNC server to accept connection from the Internet. Generally, it is only a good idea to do this only if you know exactly what you are doing, since it is a security risk. You will also have to configure your router to allow connections on the VNC ports.

Finally, the set of options in the “Show Notification Area Icon” category govern whether or not Ubuntu will display a notification icon when there is an active VNC connection. The icon looks like this:

You can set the icon to appear all the time in the notification area, allowing you quick access to the VNC settings, but generally the icon is most useful when it is set to appear when someone accesses your desktop.

Once you have selected the appropriate settings, you can save the settings by clicking on the Close button. The VNC server will run in the background, waiting for an incoming connection.

CONNECTING TO A UBUNTU VNC SERVER FROM ANOTHER UBUNTU MACHINE

Note that to connect to a VNC server, you will need to know the VNC server’s IP address.

Ubuntu includes a useful remote-desktop client application called Remmina, which allows you to connect to a VNC server. Remmina is a useful program that can connect to a variety of different server types, but for now, we’ll focus on using it to connect to a VNC server. To launch Remmina, go to the Dash, enter “remmina” into the search field, and click on the Remmina icon:

When Remmina launches, you’ll see a window that looks like this:

Click on the button with the green plus (+) sign to create a new connection. This will bring up the form for the new connection’s details:

There are quite a few options here, but for a VNC connection, the main ones are the fields marked Protocol and Server. Change the Protocol drop-down menu to VNC:

Then enter the IP address of the VNC to which you wish to connect in the Server field. (Note that in this example, the VNC server must be on the same VLAN segment as your client computer.) Once you have entered the correct IP address, click on the Connect button at the bottom of the screen.

If the VNC Server was configured to require a password, you will then see a window like this:

Enter the password, and you will be connected to the VNC server.

FORCIBLY DISCONNECTING A VNC USER

If a VNC client is connecting to your desktop and you want to forcibly disconnect it, click on the VNC icon in the notification area, and then select the Disconnect option:

When you do, you’ll see a dialog box asking if you want to disconnect the remote user:

Click the Disconnect button, and the user will be disconnected.

-JM

In this post, we’re going to explain how to use your Ubuntu 12.10 Quantal Quetzal machine both as a VNC server and as a client. VNC is an extremely useful networking protocol that allows you to remotely control a machine as if you were sitting in front of it and using its keyboard and mouse. We’ll show you how to configure your Ubuntu machine as a VNC server, and how to use Ubuntu to connect to other computers acting as VNC servers.

WHAT IS VNC?

The acronym “VNC” stands for “Virtual Network Computing”, and allows a computer with a VNC server to transmit its keyboard, mouse, and monitor information to a remote computer. This essentially allows the remote computer to control the server computer. VNC technology was originally developed by the Oracle corporation in the 1990s, and the technology was later purchased by AT&T. A variety of different VNC implementations have been developed for every operating system, and this means a VNC client on, say, a Windows computer can control a VNC server on a Ubuntu system.

SECURITY LIMITATIONS

Note that by default, the version of VNC included with Ubuntu does not encrypt the connection, so that means anyone listening in on your network can in theory see everything you do on the remote computer. So it’s best only to use Ubuntu’s VNC implementation on a local network, and on a computer that does not have high security needs.

With those limitations in mind, let’s discuss how to set up Ubuntu as a VNC server.

VNC SERVER

To access Ubuntu’s VNC server capabilities, click on the Dash (the Ubuntu icon in the upper left-hand corner of your screen) and type “Desktop Sharing” into the search box:

Click on the icon, and Desktop Sharing, the utility that controls Ubuntu’s VNC server, will then launch:

The Desktop Sharing utility offers a variety of options to customize the security and operating of Ubuntu’s VNC server. We’ll go through these options one by one.

The first option, “Allow other users to view your desktop”, allows other users to view your desktop via  a VNC client. However, in order to actual control your desktop, you need to check the “Allow other users to control your desktop” checkbox. Allowing other users to view, but not control, your desktop is useful in situations where you want other people to view your desktop without having the ability to affect your computer. For example, if you are running a presentation off your Ubuntu computer, this would allow you to share the presentation without letting the other users control your computer.

The next three options deal with security. The first, “You must confirm each access to this machine”, means that every time someone tries to connect to your Ubuntu machine via VNC, you’ll get a little pop-up box that looks like this:

This allows you to refuse or allow VNC connections to your computer.

The next option lets you set an additional password to grant access to your computer via VNC. This adds an additional layer of security to your computer, since you can grant VNC access only to users to whom you have given the VNC password. Additionally, if you decide to revoke VNC access to your machine, you can do so by the simple method of changing your VNC password.

The final option, “Automatically configure UpnP router to open and forward ports”, lets you configure the VNC server to accept connection from the Internet. Generally, it is only a good idea to do this only if you know exactly what you are doing, since it is a security risk. You will also have to configure your router to allow connections on the VNC ports.

Finally, the set of options in the “Show Notification Area Icon” category govern whether or not Ubuntu will display a notification icon when there is an active VNC connection. The icon looks like this:

You can set the icon to appear all the time in the notification area, allowing you quick access to the VNC settings, but generally the icon is most useful when it is set to appear when someone accesses your desktop.

Once you have selected the appropriate settings, you can save the settings by clicking on the Close button. The VNC server will run in the background, waiting for an incoming connection.

CONNECTING TO A UBUNTU VNC SERVER FROM ANOTHER UBUNTU MACHINE

Note that to connect to a VNC server, you will need to know the VNC server’s IP address.

Ubuntu includes a useful remote-desktop client application called Remmina, which allows you to connect to a VNC server. Remmina is a useful program that can connect to a variety of different server types, but for now, we’ll focus on using it to connect to a VNC server. To launch Remmina, go to the Dash, enter “remmina” into the search field, and click on the Remmina icon:

When Remmina launches, you’ll see a window that looks like this:

Click on the button with the green plus (+) sign to create a new connection. This will bring up the form for the new connection’s details:

There are quite a few options here, but for a VNC connection, the main ones are the fields marked Protocol and Server. Change the Protocol drop-down menu to VNC:

Then enter the IP address of the VNC to which you wish to connect in the Server field. (Note that in this example, the VNC server must be on the same VLAN segment as your client computer.) Once you have entered the correct IP address, click on the Connect button at the bottom of the screen.

If the VNC Server was configured to require a password, you will then see a window like this:

Enter the password, and you will be connected to the VNC server.

FORCIBLY DISCONNECTING A VNC USER

If a VNC client is connecting to your desktop and you want to forcibly disconnect it, click on the VNC icon in the notification area, and then select the Disconnect option:

When you do, you’ll see a dialog box asking if you want to disconnect the remote user:

Click the Disconnect button, and the user will be disconnected.

-JM