How to config URI to mysite.com/?controller/func/params

Hey,

I`m upgrading 1.7.2 to 3.0.3 and having a lot of work...

One thing I havent figured out is how to use 

mysite.com/?controller/func/params 

instead 
mysite.com/index.php/controller/function/params?

The first method works on CI 1.7.2, but doesn`t work on 3.0.3.

I didn't find nothing about it in Routing or URI...

Is this a server config (ex .htaccess) or a codeigniter config?


Thanks
(and sorry for my bad english)