Translations by Pin-hsien Lee

ubuntu-doc@lists.ubuntu.com (Ubuntu Documentation Project)

Keep your password safe. If you want to change it, you can by opening <application>About Me</application> (<menuchoice><guimenu>System</guimenu><guimenuitem>Preferences</guimenuitem><guimenuitem>About Me</guimenuitem></menuchoice>) and clicking <guibutton>Change Password</guibutton>.

Automatic login is highly discouraged because it provides less security for your system.

Open <menuchoice><guimenu>System</guimenu><guimenuitem>Administration</guimenuitem><guimenuitem>Login Screen</guimenuitem></menuchoice>.

Press <guibutton>Unlock</guibutton> and type your password to unlock the settings

Check <guilabel>Login as</guilabel>.

Choose a username from the drop down list to login as.

Press <guibutton>Close</guibutton>.

When security updates are available, the <application>Update Manager</application> automatically starts up. For other updates you will be prompted once a week. To install updates, just click <guibutton>Install Updates</guibutton> and enter your password when prompted.

Click the <application>User Switcher</application> in the top right of the panel and then press <guibutton>Lock screen</guibutton>.

Press <keycombo><keycap>Control</keycap><keycap>Alt</keycap><keycap>L</keycap></keycombo> to lock the screen. This keyboard shortcut can be changed in <menuchoice><guimenu>System</guimenu><guimenuitem>Preferences</guimenuitem><guimenuitem>Keyboard Shortcuts</guimenuitem></menuchoice>.

You can add a <guibutton>Lock Screen</guibutton> button to a panel for easy access. Right-click a panel (for example, the panel at the top of the screen), select <guibutton>Add to Panel...</guibutton> and drag the <guibutton>Lock Screen</guibutton> item to the desired location.

To unlock the screen, move the mouse or press a key. Then, type your password and either press the <keycap>Enter</keycap> key or press the <guibutton>Unlock</guibutton> button.

You may wish to install a firewall to protect your computer against unauthorized access by people on the Internet or your network. Firewalls block connections to your computer from unknown sources, which helps to prevent security breaches. If you use a router to connect to the Internet, the router may already have a firewall configured which regulates connections from the Internet to your network. This section deals with setting up a firewall on Ubuntu to regulate connections to your computer.

Firewall configuration tools

<application>Uncomplicated Firewall (UFW)</application> is the standard firewall configuration program in Ubuntu. It is a command line program. Most users will prefer to use <application>Gufw</application>, which is a graphical program to configure <application>UFW</application>.

Advanced users may wish to use <application>UFW</application> directly in the terminal. See the <ulink type="help" url="man:ufw">UFW manual</ulink> or the <ulink url="https://help.ubuntu.com/community/UFW">Community Documentation page on <application>UFW</application></ulink> for more information. Alternatively, you can use <application>iptables</application> - see the <ulink type="help" url="man:iptables">iptables manual</ulink>.

Gufw

To install and enable <application>Gufw</application>:

gufw

Install the <placeholder-1/> package.

To start <application>Gufw</application>, choose <menuchoice><guimenu>System</guimenu><guimenuitem>Administration</guimenuitem><guimenuitem>Firewall configuration</guimenuitem></menuchoice>.

To enable the firewall, simply check the box next to <guibutton>Enabled</guibutton> under <quote>Actual Status</quote>.

The default configuration is to deny connections. This means that a program attempting to connect to your computer will be denied. Certain programs or services which use the internet may require you to add an exception.

To add an exception:

Click <guibutton>Add</guibutton>.

You can choose from <guibutton>Preconfigured</guibutton> options for common programs and services, or you can manually add port exceptions in the <guibutton>Simple</guibutton> or <guibutton>Advanced</guibutton> tabs.

To find out what type of exception a particular program requires, you should consult the help for that program.

For a graphical walkthrough of basic Gufw usage, see the <ulink url="https://help.ubuntu.com/community/Gufw">Ubuntu Community Documentation page on <application>Gufw</application></ulink>.

Testing the firewall and monitoring network traffic

To test the firewall it is best to scan it from a second computer. A popular application to use is called <application>nmap</application>.

nmap

Run:

nmap -vAPN 192.168.1.100

Substitute the IP address of the computer you want to scan for <emphasis>192.168.1.100</emphasis>.

To see what services are associated with the open ports, run:

lsof -i -n -P

You can also make use of an online firewall testing service such as <ulink url="http://www.grc.com/">ShieldsUP</ulink>.

Actual monitoring of your network traffic can be done with either <application>Wireshark</application> or <application>Snort</application>. <application>Wireshark</application> can analyze network packets and <application>Snort</application> is used in Network Intrusion Detection Systems (NIDS) and will notify you of unusual traffic.

If a website asks for your financial details, ensure that it is secure. In the <application>Firefox Web browser</application>, secure websites have a <emphasis>blue</emphasis> background surrounding the icon to the left of the address bar. Additionally, the site name and a padlock icon are displayed in the lower-right corner of the browser window. Click on the padlock to read more information about the security of the website.

Writable CDs and DVDs

Alternatively, you can use a dedicated back-up application, such as <application>Simple Backup Suite</application>.

<ulink url="apt:sbackup">Install the <application>sbackup</application> package</ulink> from the <quote>Universe</quote> repository.

To make a backup, press <menuchoice><guimenu>System</guimenu><guisubmenu>Administration</guisubmenu><guimenuitem>Simple Backup Config</guimenuitem></menuchoice> and enter your administrator password when prompted.

Under <guilabel>General</guilabel> tab, choose backup mode which you would like to use. If you are not sure what you should backup, select <guilabel>Use recommended backup settings</guilabel>. This will perform daily incremental and weekly full backup of all user and system files to <filename>/var/backup</filename> default directory, excluding multimedia and temporary files as well as files larger than 100 MB.

Press <guibutton>Save</guibutton> to save your settings.

If you want to backup your files immediately, then press <guibutton>Backup Now!</guibutton>; otherwise, click <guibutton>Close</guibutton> button to leave the scheduled backup.

Your backup will launch in the background and you will see pop-up window with information about process id. Click <guibutton>Close</guibutton>. The backup process may takes a while, depend on amount of copied files.

Your backup will be placed as directory into <filename>/var/backup</filename>. You must be an <ulink type="help" url="ghelp:administrative">administrator</ulink> to access your backup.