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# Managing Cookies

This document explains what cookies are, how they are used, and how you can gain control over the cookies stored on your computer by using the Cookie Manager in &brandFullName;.

In this section:

- What is a Cookie?
- Setting Up Cookie Rules
- Accepting and Blocking Cookies
- Managing Cookies

## What is a Cookie?

A cookie is a file created by an Internet site to store information on your computer, such as your preferences when visiting that site. When you visit a site that uses cookies, the site might ask &brandShortName; to place one or more cookies on your hard disk.

Later, when you return to the site, &brandShortName; sends back the cookies that belong to the site. This allows the site to present you with information customized to fit your needs.

Cookies can also store personally identifiable information. Personally identifiable information is information that can be used to identify or contact you, such as your name, e-mail address, home or work address, or telephone number. However, a web site only has access to the personal information that you provide. For example, a web site cannot determine your e-mail address unless you provide it. Also, a web site cannot gain access to other information on your computer.

When you use the default cookie settings, this activity is invisible to you, and you won't know when a web site is setting a cookie or when &brandShortName; is sending a web site its cookie. However, you can set your cookies &pref.plural; so that you will be asked before a cookie is set.

## Setting Up Cookie Rules

By default &brandShortName; accepts all cookies. If you want to gain more control over what cookies are stored, follow these instructions:

1. Select &pref.menuPath;.
2. Click the Privacy panel and then click on the Cookies label.
3. Select the ask me every time &pref.singular; from the Keep Cookies combo box.

After this is done, you may decide exactly which cookies should and should not be saved.

### Other Settings

There are also other &pref.plural; that affect how cookies are managed by &brandShortName;. They are not needed for the cookie rules to work but are explained anyway:

Allow sites to set cookies

  If you don't want any sites to store cookies on your computer, uncheck this &pref.singular;. Note that some sites may not work properly when cookies are disabled.

for the originating web site only

  If &brandShortName; stores a site's cookie, it will return the cookie only to that particular site. &brandShortName; will not provide one site with cookies set by another. Since a web site can only receive its own cookies, it can learn about your activities while you are at that site but not your activities in general while surfing the Web.

  However, sometimes a web site displays content that is hosted on another site. That content can be anything from an image to text or an advertisement. The other web site that hosts also has the ability to store a cookie in &brandShortName;, even though you haven't visited the site directly.

  Cookies that are stored by a site other than the one you are visiting are called third-party cookies or foreign cookies. Web sites sometimes use third-party cookies with transparent GIFs, which are special images that help sites count users, track email responses, learn more about how visitors use the site, or customize your browsing experience. (Transparent GIFs are also known as web beacons or web bugs.) When this checkbox is checked, it blocks these foreign cookies from being saved.

Keep Cookies:
  - until they expire: If this &pref.singular; is selected, cookie information will be removed when it hits its expiration date.
  - until I close &brandShortName;: If this &pref.singular; is selected, the cookie information will be removed when you restart &brandShortName;. Web sites requiring the use of cookies will still work, but if you restart &brandShortName;, the web site will think that you logged into the site for the first time again.
  - ask me every time: Display an alert every time a web site tries to store a cookie to ask you if you want that cookie stored.

## Accepting and Blocking Cookies

Assuming that you've enabled the cookie rules explained above, you'll see a dialog whenever a site tries to save a cookie on your computer:

Allowing a Cookie
  To allow this particular cookie, just click Allow. If you trust the site and don't want this dialog to be shown each time the site tries to save a cookie, check the Use my choice for all cookies from this site checkbox and then click Allow. &brandShortName; will remember this and never ask about cookies for this site again. If you later regret your choice, read about the Cookie Manager.
Blocking a Cookie
  If you don't want this cookie to be saved, click Deny. If you don't trust the site or suspect that it's compromising your privacy, check the Use my choice for all cookies from this site checkbox and then click Block. &brandShortName; will then put this site on the list of blocked sites and never save cookies for it. This choice can be undone using the Cookie Manager.

## Managing Cookies

Use the Cookie Manager to view and remove cookies and manage per-site cookie &pref.plural;. It is accessible through the Cookies section in the Privacy tab of &pref.singularCaps;.

### The Cookie List

The Cookie Manager dialog lists all cookies currently stored on your computer. You can select them to display more information about them. Use the View Cookies button in cookies &pref.plural; to access this window.

To remove a cookie from the list, select it and click Remove Cookie. To remove all cookies, click Remove All Cookies. (This is the same as clicking the Clear button from the Privacy panel of the &pref.pluralCaps; window.)

Don't allow sites that set removed cookies to set future cookies
Even if you remove cookies now, you will reacquire those same cookies the next time you return to the web site. To prevent that from happening, select this checkbox. When this checkbox is selected, web sites for the cookies that you are removing are added to the list of sites whose cookies will automatically be rejected. Important: You must check this &pref.singular; before you start to remove cookies, or the sites will not be added to the list of blocked sites.

### The Site List

This is the list of sites that are either allowed or not allowed to store cookies on your computer. In the Status column, you can see if a site is blocked or allowed. Use the Exceptions button in cookies &pref.plural; to access this window.

To add a site to the this list, simply type the site's domain name in the field labeled Address of web site:. Then click Block to reject cookies from the site, or click Allow to allow cookies from the site.

To remove a site from this list, select it and click Remove Site. To clear the list completely, click Remove All Sites. This will reset the cookie rules and you will see dialogs for each cookie again.

02 October 2004

Copyright © 2003-2004 Contributors to the Mozilla Help Viewer Project.