Translations by Nick Ellery

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

Keeping Your Computer Safe

2006-09-07

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Ubuntu Documentation Project

Canonical Ltd. and members of the <placeholder-1/>

The Ubuntu Documentation Project

This section describes how to keep your computer safe from security threats.

Give a separate user account to each person

When Ubuntu is installed, it is set up for a single person to use. If more than one person will use the computer, it is best for each person to have their own user account. This way they can have separate settings, documents, and other files. If necessary, files can also be protected from being viewed or changed by non-administrators.

To set up user accounts, choose <menuchoice><guimenu>System</guimenu><guimenuitem>Administration</guimenuitem><guimenuitem>Users and Groups</guimenuitem></menuchoice>. You must be an <ulink type="help" url="ghelp:administrative">administrator</ulink> to do this.

See the <ulink type="help" url="ghelp:users-admin">Users Administration Tool manual</ulink> for more information on setting up user accounts.

Keep your software up to date

Ubuntu developers often issue updates to the Ubuntu software. These updates may improve security or fix other problems.

The update process may take a while if many updates need to be installed.

If a pair of blue arrows appears in the panel when the updates have finished, you need to restart the computer to complete the installation.

To check for updates yourself, choose <menuchoice><guimenu>System</guimenu><guimenuitem>Administration</guimenuitem><guimenuitem>Update Manager</guimenuitem></menuchoice> and press <guibutton>Check</guibutton>.

Lock your screen while away

Locking your screen prevents other people from accessing your computer while you are away from it. All of your applications and work remain open while the screen is locked, and the screensaver is displayed.

You can lock your screen in one of the following ways:

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.

If more than one person has a user account on your computer and the screen is locked, other users can press the <guibutton>Switch user...</guibutton> button to use the computer, even while the screen is locked. They will be unable to access your currently-open work, and you will be able to switch back to your locked session when they have finished using the computer.

Set up a firewall

Avoid Internet nuisances and crime

From time to time, you may be sent an email which carries a virus or links to a fraudulent website. This type of email is very common, and it is important to learn how to deal with it, in order to prevent your computer or your personal details from being compromised or misused.

Such messages are often received from total strangers. However, sometimes an email may appear to be from someone you know, when really it is not. This is because it is possible to include a fake sender email address in emails.

Unwanted (unsolicited) mail tends to fall in to one of several categories:

Spam (junk) email, where people offer unwanted services and products

Scam emails, where people pretend to ask for help in exchange for large sums of money

Phishing email, where the message appears to be from a bank or other online service, asking you to enter your personal and financial details, or passwords.

Below are some tips for keeping safe online:

You should never reply to unsolicited mail, or even click on the links in the mail. Doing so usually results in more junk mail being sent to you.

Never click on links in emails which lead to websites asking for your password or similar. It is possible for the text of the link to give one address, when really it opens up another (possibly dangerous) address. Instead, type the link into your web browser yourself and proceed from there.

Only download and run software from sources that you trust. By default, you can only download software directly from Ubuntu.

Make backup copies of your files

A problem which you may occasionally encounter is the unexpected loss of some of your work and settings for one reason or another. The causes of such <emphasis>data loss</emphasis> are many and varied; it could be anything from a power cut to accidentally deleting a file. It is highly recommended that you make regular back-up copies of your important files so that, if you do encounter a problem, you will not have lost those files.

It is wise to store back-up copies of files separately from your computer; that is, you should make use of some form of file storage which is not permanently attached to your computer. Options include:

Writable CDs and DVDs

External hard disks and flash memory devices

Another computer on the network

A simple way of backing-up your files is to manually copy them to a safe location (see above) by using the <application>File Browser</application>.

Some general advice on how to keep good back-ups is given below:

Back-up on a regular basis

Always test your back-ups after you make them, to ensure that they have been made correctly

Label your back-ups clearly, and keep them in a safe place