I am trying to add the RequireHttps tag to a controller action but when I try to navigate to it I get a page not found error when I try: https://localhost/MVCDemo3_4/Home/Index2 or http://localhost/MVCDemo3_4/Home/Index2
The Http one tries to redirect to HTTPS but then the HTTPS can't find the page.
It depends more on how this is being hosted than the MVC attribute. If it's running off of a real IIS (or other full httpd) server on locahost, then you just need to make sure IIS is listening on both 80 and 443 (as @Jester mentioned, check the bindings). However, if you are using IIS Express via Visual Studio, then you really can only listen on one port and your debugging needs to be either all non-SSL or all SSL. This is controlled through the propeties on the Web project. Look at the Project URL field.