Session lost after redirect in Codeigniter

Question

I'm using codeigniter as a framework.

Firstly, I use localhost but when I change to my IP address the login function doesn't work anymore. I found that the session is lost after redirect to another controller.

Here is the result of print_r($this->session->all_userdata());

[session_id] => 7b00fa0f8790f48d24446f9eb4e6aab2 
[ip_address] => 10.42.68.71 
[user_agent] => Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.83 Safari/537.1
[last_activity] => 1285962398 
[user_data] =>

As you can see it doesn't have any data passed to user_data but it was set before redirect when I test.

I separate the controller to two which the first one is users -> handler of login function and another is planner which handler of the link that I redirect from users controller.

users.php (first controller):

$this->load->model('users_model');
$this->load->model('mymodel');
$this->load->database();

$email = $this->input->post('email');

$pass = $this->input->post('password');

$type = $this->input->post('type');

// Authenticate the user
$userdata = $this->users_model->auth_user($email,$pass,$type);

if($userdata)
{
    $data = array('FIRSTNAME' => $userdata->FIRSTNAME, 
                  'LASTNAME' => $userdata->LASTNAME, 
                  'EMAIL' => $userdata->EMAIL,
                  'LOGIN' =>TRUE, 'TYPE' => $type);
    $this->session->set_userdata($data);
    redirect('planner/view_system','refresh');
}

planner.php (second controller):

function __construct() {
    parent::__construct();

    if ( ! ($this->session->userdata('LOGIN')))
    { 
        print_r (var_dump($this->session->userdata('FIRSTNAME')));
        print_r($this->session->all_userdata());
    }
    $this->load->helper(array('form','html','url'));

And here is my config

$config['sess_cookie_name']     = 'ci_session';
$config['sess_expiration']      = 7200;
$config['sess_expire_on_close'] = FALSE;
$config['sess_encrypt_cookie']  = FALSE;
$config['sess_use_database']    = FALSE;
$config['sess_table_name']      = 'ci_sessions';
$config['sess_match_ip']        = TRUE;
$config['sess_match_useragent'] = FALSE;
$config['sess_time_to_update']  = 300;

Answer 1

I have the exact same problem and here's what I do. First, go to file system/libraries/Session/Session.php. Comment session_start(); on line 140. On function _configure, comment few lines under // Security is king

//      ini_set('session.use_trans_sid', 0);
//      ini_set('session.use_strict_mode', 1);
//      ini_set('session.use_cookies', 1);
//      ini_set('session.use_only_cookies', 1);
//      ini_set('session.hash_function', 1);
//      ini_set('session.hash_bits_per_character', 4);

Second, go to file index.php on your root project. Put, session_start(); below <?php

Hope this helps.