redirect url helper redirect to localhost

Hi,

When a call a redirect url helper function this function as following:

redirect('controller/method');

redirect to http://localhost/index.php/controller/method

If I set base_url variable on config file works correctly and redirect to http://myvirtualhost.com/index.php/controller/method but this not was necessary on codeigniter 2 and can be a problem because we must to define a base_url per environment.

Greetings.