Managing cookies in the Firefox browser is done through the menu “Tools-Options” (figure 1). The dialog box for the “Options” setting in shown in Figure 2. The “Privacy” setting is where Internet cookies are configured.
Click the ( +) by the entry “Cookies” to open the options for configuring cookies. Figure 3 shows the settings. Cookies can be blocked entirely by removing the check by “Allow sites to set cookies”. Unfortunately, that will cause some sites to refuse to load and will disable functions in some other sites. Cookies are so widely used that it is impracticable to block all cookies. However, it is usually safe to block so-called third party cookies by checking “for the originating site only”. It is also feasible to use the so-called “session only” method. In the drop-down box by “Keep Cookies:”, choose “Until I close Firefox”. Before doing this, however, first add all the sites where you need cookies to the list that can be configured by clicking “Exceptions”. Figure 4 shows the dialog box for making a list. Lists of sites whose cookies are blocked or allowed for session-only can be made but, in practice, making a list whose cookies are allowed and making all others into session cookies seems to me to be the most reasonable way to go.
Once you have made a list of all the sites whose cookies you need or are willing to accept, your overall cookie settings might look like like those in Figure 5.