This setting only works for a redirection via a permanently moved location header in the HTTP response headers. There are a lot more ways to refresh a page. ----- The setting in "Options/Preferences > Advanced > General : Accessibility" is meant as an accessibility feature, as you can see by the label of that section, so that people with disabilities or people who use screen readers do not get confused and is not meant as a safety protection to stop redirecting. See also: *https://support.mozilla.org/kb/settings-network-updates-and-encryption#w_general-tab *http://kb.mozillazine.org/accessibility.blockautorefresh *http://kb.mozillazine.org/Accessibility_features_of_Firefox