Middleware

Route::get('admin/profile', ['middleware' => 'auth', $callback/clousure ]);

Route::get( .. .. )->middleware(['first', 'second']);

// Middleware in group routes
Route::group(['prefix' => 'admin' , 'middleware' => 'auth'] , function(){
    Route::get('/posts' , function(){
        //
    });
    Route::get('/pages' , function(){
        //
    });
    Route::get('/categories' , function(){
        //
    });
});

Controller Middleware

Route::get('profile', [
    'middleware' => 'auth',
    'uses' => 'UserController@showProfile'
]);

class UserController extends Controller {

    /**
     * Instantiate a new UserController instance.
     */
    public function __construct()
    {
        $this->middleware('auth'); // middle ware to all metods

        // only for some methods
        $this->middleware('log', ['only' => ['fooAction', 'barAction']]);

        // All but except some methods
        $this->middleware('subscribed', ['except' => ['fooAction', 'barAction']]);


        $this->middleware('auth')->except(['index' , 'show']);

    }

}