Current versions of Firefox do not implement any kind of guest wifi portal detection. They also do not permit some secure sites to be intercepted (such as Google, Facebook, etc). As a result, you will see a security warning that the page cannot be displayed, but you will not given an option to display the page. This is not an issue with UF Guest, but rather a lack of portal detection support in Firefox. Future Firefox versions may implement this detection. Chrome, Safari, and Internet Explorer seem to work fine. For Firefox, we recommend you first browse to a non-secure website such as www.ufl.edu to be allowed access to the AUP screen.