Information
This setting enables or disables the ability for third-party cookies to be downloaded to the system. Third party cookies are cookies sent by a domain that differs from the domain in the browser's address bar.
Rationale:
Third party cookies are often used for tracking user browsing behaviors, which has privacy implications. However, preventing third-party cookies does not completely mitigate privacy concerns as several other active tracking mechanisms exist [1].
Impact:
Blocking third-party cookies may adversely affect the functionality of some sites.
Solution
To establish the recommended configuration, set network.cookie.cookieBehavior to 1:
Type about:config in the address bar
Type network.cookie.cookieBehavior in the filter
Ensure the setting is set as prescribed.
OR
Open the mozilla.cfg file in the installation directory with a text editor
Add the following lines to mozilla.cfg:
lockPref('network.cookie.cookieBehavior', 1);
Default Value:
5