Managing Cookies

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 Mozilla Firefox.

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 Firefox to place one or more cookies on your hard disk.

Later, when you return to the site, Firefox 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 Firefox is sending a web site its cookie. However, you can set your cookies options so that you will be asked before a cookie is set. You can also restrict the lifetime of cookies to your current Firefox session.

Setting Up Cookie Rules
By default Firefox accepts all cookies, including cookies which would allow a site to recognize you effectively forever. If this doesn't suit you, you can tell Firefox to delete all cookies when you close Firefox:

1. Select Tools > Options and open the Privacy panel.

2. Select the I close Firefox option from the Keep until menu.

If you want to grant sites you trust the ability to store cookies permanently (e.g., to allow you to log in automatically to a site), click Exceptions..., enter the site address, and click Allow.

All the Settings
These are the options that affect how cookies are managed by Firefox:

Accept cookies from sites
If you don't want any sites to store cookies on your computer, uncheck this option. Note that some sites may not work properly when cookies are disabled. If you want to grant certain sites the ability to store cookies, open the Cookies Exceptions window by clicking Exceptions..., enter the site address, and click Allow or Allow for Session.

Keep until:
* they expire

If this option is selected, each cookie will be removed when the
site that set it has determined the cookie should expire.

* I close Firefox

If this option is selected, cookies will be removed when you
restart Firefox. Web sites requiring the use of cookies will
still work, but if you restart Firefox, 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 asking you
if you want that cookie stored.