“FWIW IM is a GR8 way to communicate, BICBW.” If you can read that, you are one of the many people adept at communicating via instant message. Instant messaging (IMing) works through a little program that runs on your computer, allowing you to chat in real time with another computer user anywhere in the world. Unlike chat rooms, instant messaging happens between two people rather than a large group. For young people, instant messaging has become a common form of communicating. For the business world, instant messaging allows for communication and collaboration.
Users of Ubuntu have the ability to install any number of instant messaging programs on their computer. While many of these can be installed through the Add/Remove tool, a program called Pidgin has been preinstalled on Ubuntu so that users can start IMing their friends right from the start.
Pidgin is actually a multiprotocol instant message client. Common instant message programs like ICQ, MSN, AIM, and others can only communicate with computer users who are running the same program. For instance, someone using ICQ can only IM other ICQ users. Unfortunately, most people use more than one instant messaging program. It is not uncommon for a person to have an ICQ account, an MSN account, an AIM account, and a Yahoo! account. Pidgin, a multiprotocol client, allows users to manage all of their accounts from one client.
Pidgin gets its name from the term pidgin used to describe a mixture of languages that develops from neighboring countries to allow for trade.
Start Pidgin by selecting Applications | Internet | Pidgin. If this is the first time you have opened Pidgin, you will be alerted to the fact that no IM accounts have been configured. Click Add to get started configuring Pidgin.
After clicking Add, you are brought to the Add Accounts screen. The first step in adding an account is selecting the protocol to be used. The Protocol menu allows you to select what IM service you are setting up your account for. For instance, if you are adding an MSN account, select that from the protocol list.
You can add more protocols to Pidgin at any time by going to Accounts | Manage |
Add from within the Pidgin Buddy List window.
After you have selected the protocol, you need to provide your Screen Name, Password, and Local Alias that you use for your instant messaging service. You can also select the Remember Password option if you do not wish to have to supply your password every time you use the protocol. If you have forgotten any of this information, you may have to log in through the client provided by your service to find it. The Add Account window has an Advanced tab that allows you to change the port number for your IM protocol and to change the proxy options. If you are setting this up at home, you probably won’t have to worry about the Advanced tab. If this is something you are installing at work, check with your network administrator to see if these are the right settings.
Once you have added an account to Pidgin, you can log in and start communicating. If you are new to instant messaging, you need to first add some buddies to your list. To add a buddy, you will need his or her screen name. Once you have that, go to Buddies |
Add Buddy. If you look over the Buddies menu, you can see that from here you can also add a group to better organize your buddy lists, show different information about your buddies, sort your buddies, and get information about other users. To send a new message, simply go to Buddies | New Instant Message. You will need to enter the name of the person you wish to IM, and then you can send your message if they are online. Since instant messaging oftentimes takes the place of a phone conversation, emphasis and tone can be communicated as well. When sending a message, you can use the Smile button to bring up various emoticons that can set the tone for your message. Emoticons are extremely popular when sending IMs.
From the Tools menu of the Pidgin Buddy List, you can set your preferences for how Pidgin operates, add plug-ins for Pidgin, set privacy options, and even transfer files to your buddies. So if there are no further questions, TAFN!
Source of Information : McGraw Hill Osborne Media How to Do Everything Ubuntu
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One common misconception about GNU/Linux is that no viruses exist for this operating system. This is simply not true. For quite some time GNU/Linux did not feel the constant pressure of malware attacks that Microsoft Windows did. While researchers did write viruses that could infect the GNU/Linux operating systems, they were for research purposes only. However, viruses have since been released that have the ability to infect computers running a GNU/Linux operating system. More and more, people are beginning to see viruses “in the wild” that can damage these operating systems.
A virus that has been released to the public is said to be “in the wild.” This is how security experts can differentiate between a virus that is for research and one whose intent is to cause harm to a computer system. Purely as a hobby some people collect malware “in the wild” so that they can analyze the code of the malware and help fight against it.
Ubuntu, remember, was built on the philosophy that Ubuntu “Just Works.” For Ubuntu to work properly, antivirus software had to be made available to the users of Ubuntu. Antivirus software works in a number of ways. First of all, this software needs to have the ability to detect malware on a computer system by knowing what to look for. This information is provided by a signatures file that the software will download and install automatically. If these signatures are outdated, then the computer is vulnerable to the latest malware.
Signature files are also called “definition files” by certain antivirus applications.
Since most antivirus software manufacturers charge not only for the application but also for a yearly subscription for the virus definitions file, finding one that fits the Ubuntu software model might seem a bit difficult. Fortunately, quite a few companies have opted not to charge home users for antivirus software and the definitions. From this list, the Ubuntu community chose ClamTk since it falls under the GNU Public License.
Installing ClamTk
Installing ClamTk is very easy. Start by going to the Add/Remove tool. You do remember how to get there, right? From the categories on your left, select System Tools and then scroll down the list until you see Virus Scanner. From here simply select this application and then click Apply Changes as you have done before. Voilà! You have protected your computer against malware.
Updating the Signature File
Now that you have successfully installed the application, you will want to update the signature files. The easiest way to do this is to open the terminal window and type the following:
wget http://db.local.clamav.net/daily.cvd
When you press ENTER, it displays the download process of the virus signature file. Now, you need to move the file to the proper directory by typing
sudo mv daily.cvd /var/lib/clamav
This will put the updated file into the clamav folder so that the application will use the latest signatures. Once you press ENTER, you will be asked for your password. Upon entering this successfully, you will be taken back to the terminal prompt. You can now exit the terminal so you can run a virus scan.
Scanning the Computer
While most antivirus applications that run on Microsoft Windows actively scan the computer for malware, ClamTk does not. Instead, you are required to do a passive scan where you actually tell it to scan the computer for malware. Remember, while some malware can infect a computer running GNU/Linux, few can. The odds of you picking up a virus in the wild are slim, and if you only install software from the repositories, then you have a good chance of never having an infection. However, it is still a good idea to scan your computer from time to time. Once a week is a good schedule for most users, while those who download a large number of files and who open e-mail attachments may want to scan their computer more often. To scan the computer, you need to launch the ClamTk window from the Applications tab. However, if you open this tab, the System Tools category where ClamTk resides may not be listed there. If you find this to be the case, instead of opening the Applications tab, right-click it and select Edit Menus so that it brings up a window. Now select System Tools and then place a check mark next to Virus Scanner. Click Close and open the Applications tab. Select System Tools | Virus Scanner to launch the application.
Now that the application window for ClamTk is open, select File and then Full Home Scan. This will scan your home directory. You can also select to scan individual files if you downloaded something questionable, or individual directories for security reasons.
Source of Information : McGraw Hill Osborne Media How to Do Everything Ubuntu
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No, we are not installing a copy of Drew Barrymore’s early work. We are installing one of the most essential parts of a sound computer security plan, the firewall. Over the years, the term “firewall” has been misunderstood by some. It is sometimes defined as a tool that restricts access to certain web sites. Although some firewalls contain such content filters, this is not the main purpose of a firewall. A firewall is a tool that restricts access to a computer system or network by controlling access to a computer’s ports, which serve as endpoints to data connections. In Ubuntu, the default installation does not open any ports on the computer. Most computer systems have no need for any ports to be opened, so opening no ports during installation does not hinder the performance of the computer.
If Ubuntu does not open any ports at installation, why do you need a firewall? Good question. Although you have no open ports on your computer from the start, you may decide to open certain ports later for features such as remote access, or to host a web server. In any event, when a port on the computer is opened, you need a firewall. If you decide to keep the installation as is and not to open any ports, a firewall can still provide you with important security information. When running a firewall, you are provided information about other computers that are scanning your computer for open ports. While most of these scans are just random, should you see that a particular computer is continually scanning your computer, you may have a problem that you need to contact your Internet provider about. As you become more comfortable with Ubuntu, you may want to set policies on Firestarter. Policies are the rules that the firewall must abide by and are broken down into inbound and outbound policies. By default, Firestarter adheres to the following policies:
• New inbound connections from the Internet to the firewall or client hosts are blocked.
• The firewall host is freely allowed to establish new connections.
• All client hosts are allowed to establish new connections to the Internet, but not to the firewall host.
• Traffic from the Internet in response to connection requests from the firewall or client hosts is allowed back in through the firewall.
Installing Firestarter is simple. Start by going to the Applications menu, and then go to Add/Remove. When the Add/Remove tool is launched, search for the term “Firestarter” in all available applications. Now go through the normal application installation procedures as you have in the past. Once the software is installed, you will need to go to Applications | Internet | Firestarter to launch the program. Once you do this, you will be asked to provide your password. There’s that security at work!
When you click Forward on the welcome screen, you are brought to the Network Device Setup screen. On this screen, you will see the device that allows you to connect to the Internet. Most people will see Ethernet Device (eth0). If you have something different, that is okay. Ubuntu and Firestarter have worked together to determine the network device your computer uses to connect to the Internet so you would select whatever the Network Device Setup screen provides for you. The next part is important. If you did not give your network device an IP address, check IP Address Is Assigned Via DHCP. If you do not remember if you gave your device an IP address, then check this box. Most people will wind up with this box checked. Now you can click Forward.
If you selected IP Address Is Assigned Via DHCP in the previous screen, leave this screen blank and click Forward. Although you may be sharing an Internet connection at home, the Enable Internet Connection Sharing option has a different meaning. This is for computers that allow other computers to connect through their device. It’s unlikely anyone reading this book will need to select this, but if other computers connect through your computer, then check this box. You’ve reached the final configuration stage. Make sure that the Start Firewall Now box is checked and click Save.
Once you click Save, the Firestarter window opens. You can take some time to look over the different options that the firewall has, but don’t change anything, especially the policies. You could disable your ability to get onto the Internet if you set this improperly. Although policies are beyond the scope of this book, the Ubuntu forums provide plenty of information regarding Firestarter. Again, this is one of the benefits of using Ubuntu-supported software! Now, if you want to see Firestarter actually do something, leave this window open, and then open the Firefox web browser. Surf to a couple of sites, and then go back to Firestarter.
Note that the Received and Sent fields have changed. That is because this firewall will log the amount of data transferred on the network device that is active. This information can be helpful because if you are not on the Internet and you notice a heavy amount of traffic on your network device, someone or something may be transferring data without your knowledge.
Once you have familiarized yourself with Firestarter, notice the blue circle with a black arrowhead in your top toolbar. This is an icon to open the Firestarter window and lets you know that the firewall is active. If you click this icon, the Firestarter window will disappear, but the firewall will still protect your computer. If you close the Firestarter window, you will close the program and risk running without firewall protection.
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You can change many of the visual attributes of the Konqueror window, including which menu bars and toolbars appear. You can have any of the following bars appear on the Konqueror window: Menubar, Toolbar, Extra Toolbar, Location Toolbar, and Bookmark Toolbar. Select Settings, and then click the bar you want to have appear (or not appear). The bar appears when a check mark is shown next to it.
You can modify a variety of options for Konqueror by choosing Settings -> Configure Konqueror. The Konqueror Settings window appears, offering the following options:
- Behavior (File)—Change file manager behavior.
- Appearance—Change file manager fonts and colors.
- Previews & Meta-Data—An icon in a Konqueror folder can be made to resemble the contents of the file it represents. For example, if the file is a JPEG image, the icon representing the file could be a small version of that image. Using the Previews features, you can limit the size of the file used (1MB is the default) because many massive files could take too long to refresh on the screen. You can also choose to have any thumbnail embedded in a file to be used as the icon or have the size of the icon reflect the shape of the image used.
- File Associations—Describes which programs to launch for each file type.
- Web Behavior—Click the Behavior (Browser) button to open a window to configure the Web browser features of Konqueror. By enabling Form Completion, Konqueror can save form data you type and, at a later time, fill that information into other forms. If your computer has limited resources, you can speed up the page display by clearing the Automatically Load Images check box or by disabling animations.
- Java and JavaScript—Enable or disable Java and JavaScript content contained in Web pages in your Konqueror window.
- AdBlock Filters—Click here to create a list of URLs that are filtered as you browse the Web. Filtering is based on frame and image names. Filtered URLs can be either thrown away or replaced with an image. You can also import and export lists of filters here.
- Fonts—Choose which fonts to use, by default, for various fonts needed on Web pages (standard font, fixed font, serif font, sans serif font, cursive font, and fantasy font). The serif fonts are typically used in body text, while sans serif fonts are often used in headlines. You can also set the Minimum and Medium font sizes.
- Web Shortcuts—Display a list of keyword shortcuts you can use to go to different Internet sites. For example, follow the word “ask” with a search string to search the Ask
Jeeves (www.ask.com) Web site.
- History Sidebar—Modify the behavior of the list of sites you have visited (the history).
By default, the most recent 500 URLs are stored, and after 500 days (KNOPPIX) or 90 days (Fedora), a URL is dropped from the list. There’s also a button to clear your history. (To view your history list in Konqueror, open the left side panel, and then click the tiny scroll icon.)
- Cookies—Choose whether cookies are enabled in Konqueror. By default, you are asked to confirm that it is okay each time a Web site tries to create or modify a cookie. You can
change that to either accept or reject all cookies. You can also set policies for acceptance or rejection of cookies based on host and domain names.
- Cache—Indicate how much space on your hard disk can be used to store the sites you have visited (based on the value in the Disk Cache Size field).
- Proxy—Click Proxy to configure Konqueror to access the Internet through a proxy server (by default, Konqueror tries to connect there directly). You need to enter the address and port number of the computer providing HTTP and/or FTP proxy services. Alternatively, you can have Konqueror try to automatically detect the proxy configuration.
- Stylesheets—Choose whether to use the default stylesheet, a user-defined stylesheet,
or a custom stylesheet. The stylesheet sets the font family, font sizes, and colors that are
applied to Web pages. (This won’t change particular font requests made by the Web page.) If you select a custom stylesheet, click the Customize tab to customize your own fonts and colors.
- Crypto—Display a list of secure certificates that can be accepted by the Konqueror browser. By default, Secure Socket Layer (SSL) versions 2 and 3 certificates are accepted,
as is TLS support (if supported by the server). You can also choose to be notified when you are entering or leaving a secure Web site.
- Browser Identification—Set how Konqueror identifies itself when it accesses a Web
site. By default, Konqueror tells the Web site that it is the Mozilla Web browser. You can select Konqueror to appear as different Web browsers to specific sites. You must sometimes do this when a site denies you access because you do not have a specific type of browser (even though Konqueror may be fully capable of displaying the content).
- Plugins—Display a list of directories that Konqueror will search to find plug-ins. Konqueror can also scan your computer to find plug-ins that are installed for other browsers in other locations.
- Performance—Display configuration settings that can be used to improve Konqueror performance. You can preload an instance after KDE startup or minimize memory usage.
Source of Information : Linux Bible 2008 Edition
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Dozens of text editors are available for use with Linux. Here are a few that might be in your Linux distribution, which you can try out if you find vi to be too taxing.
Nano. A popular, streamlined text editor that is used with many bootable Linuxes and other limited-space Linux environments. For example, nano is often available to edit text files during a Linux install process.
Gedit. The GNOME text editor that runs in the GUI.
Jed. This screen-oriented editor was made for programmers. Using colors, jed can highlight code you create so you can easily read the code and spot syntax errors. Use the Alt key to select menus to manipulate your text.
Joe. The joe editor is similar to many PC text editors. Use control and arrow keys to move around. Press Ctrl+C to exit with no save or Ctrl+X to save and exit.
Kate. A nice-looking editor that comes in the kdebase package. It has lots of bells and whistles, such as highlighting for different types of programming languages and controls for managing word wrap.
Kedit. A GUI-based text editor that comes with the KDE desktop.
Mcedit. With mcedit, function keys help you get around and save, copy, move, and delete text. Like jed and joe, mcedit is screen-oriented.
Nedit. An excellent programmer’s editor. You need to install the optional nedit package to get this editor.
If you use ssh to log in to other Linux computers on your network, you can use any editor to edit files. A GUI-based editor will pop up on your screen. When no GUI is available, you will need a text editor that runs in the shell, such as vi, jed, or joe.
Source of Information : Linux Bible 2008 Edition
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Although similar in many ways, the Linux file system has some striking differences from file systems used in MS-DOS and Windows operating systems. Here are a few:
In MS-DOS and Windows file systems, drive letters represent different storage devices (for example, A: is a floppy drive and C: is a hard disk). In Linux, all storage devices are fit into the file system hierarchy. So, the fact that all of /usr may be on a separate hard disk or that /mnt/rem1 is a file system from another computer is invisible to the user.
Slashes, rather than backslashes, are used to separate directory names in Linux. So, C:\home\chris in an MS system is /home/chris in a Linux system.
Filenames almost always have suffixes in DOS (such as .txt for text files or .doc for wordprocessing files). Although at times you can use that convention in Linux, three-character suffixes have no required meaning in Linux. They can be useful for identifying a file type. Many Linux applications and desktop environments use file suffixes to determine the contents of a file. In Linux, however, DOS command extensions such as .com, .exe, and .bat don’t necessarily signify an executable (permission flags make Linux files executable).
Every file and directory in a Linux system has permissions and ownership associated with it. Security varies among Microsoft systems. Because DOS and MS Windows began as single-user systems, file ownership was not built into those systems when they were designed. Later releases added features such as file and folder attributes to address this problem.
Source of Information : Linux Bible 2008 Edition
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