PHP session cleared after page loads in ie - php

Question

I'm working on a site that has a My Account section that the user has to login to. I'm storing the users basic information in the session after they have logged in.
I'm having no problem in Chrome or Firefox with this. However, in IE 8 I login, and it redirects to the main back office page. It loads, but right after the session is cleared. I tested this by printing the session after session_start() then again at the end of the page. All the information is there when the page loads. If I open a separate page and print out the session right after, it's already cleared. Again, only in IE does this happen.
Is there something I'm missing here?
CODE
This is the code on all of the Account pages.
<?php
require_once('inc_session.php');
require_once('bo_session_check.php');
?>
On the page logged into (backoffice.php), the only other time the session is used, is when it is read to determine what kind of account the person has logged into, for example:
<?php if($_SESSION['user_type']=='member'){?>
Code for inc_session.php
<?php
if(!isset($_SESSION['is_mobile'])){
$mobile_browser = '0';
if (preg_match('/(up.browser|up.link|mmp|symbian|smartphone|midp|wap|phone|android)/i', strtolower($_SERVER['HTTP_USER_AGENT']))) {
$mobile_browser++;
}
if ((strpos(strtolower($_SERVER['HTTP_ACCEPT']),'application/vnd.wap.xhtml+xml') > 0) or ((isset($_SERVER['HTTP_X_WAP_PROFILE']) or isset($_SERVER['HTTP_PROFILE'])))) {
$mobile_browser++;
}
$mobile_ua = strtolower(substr($_SERVER['HTTP_USER_AGENT'], 0, 4));
//echo $_SERVER['HTTP_USER_AGENT'];
$mobile_agents = array(
'w3c ','acs-','alav','alca','amoi','audi','avan','benq','bird','blac',
'blaz','brew','cell','cldc','cmd-','dang','doco','eric','hipt','inno',
'ipaq','java','jigs','kddi','keji','leno','lg-c','lg-d','lg-g','lge-',
'maui','maxo','midp','mits','mmef','mobi','mot-','moto','mwbp','nec-',
'newt','noki','oper','palm','pana','pant','phil','play','port','prox',
'qwap','sage','sams','sany','sch-','sec-','send','seri','sgh-','shar',
'sie-','siem','smal','smar','sony','sph-','symb','t-mo','teli','tim-',
'tosh','tsm-','upg1','upsi','vk-v','voda','wap-','wapa','wapi','wapp',
'wapr','webc','winw','winw','xda ','xda-');
if (in_array($mobile_ua,$mobile_agents)) {
$mobile_browser++;
}
if (strpos(strtolower($_SERVER['ALL_HTTP']),'OperaMini') > 0) {
$mobile_browser++;
}
if (strpos(strtolower($_SERVER['HTTP_USER_AGENT']),'ipad') > 0) {
$mobile_browser++;
}
if (strpos(strtolower($_SERVER['HTTP_USER_AGENT']),'windows') > 0) {
$mobile_browser = 0;
}
if ($mobile_browser > 0) {
$_SESSION['is_mobile']='yes';
}
else {
$_SESSION['is_mobile']='no';
}
}
/* TURN MOBILE SITE OFF */
//$_SESSION['is_mobile']='no';
$page=strtok($_SERVER["REQUEST_URI"],'?');
if(substr($page, 0, 3)!="/m/" && $_SESSION['is_mobile']=='yes' && substr($page,-3) =='php'){
if( isset($_SERVER['HTTPS'] ) && $_SERVER['HTTPS'] != 'off' ){
$heading='https://';
}else{
$heading='http://';
}
header("Location: " . $heading . $_SERVER["SERVER_NAME"] . "/m" . $_SERVER["REQUEST_URI"]);
exit();
}
$page=substr($page, strrpos($page, '/', -1));
$ssl_pages=array('/backoffice.php', '/login.php', '/login-partner.php', '/checkout.php', '/checkout_member.php', '/membership.php', '/partner.php');
if(in_array($page, $ssl_pages) || substr($page, 0, 3)=='/bo'){
if($_SERVER[HTTP_HOST]!='domain.com'){
header("Location: https://domain.com" . $_SERVER["REQUEST_URI"]);
}elseif($_SERVER["HTTPS"] != "on") {
header("HTTP/1.1 301 Moved Permanently");
header("Location: https://" . $_SERVER["SERVER_NAME"] . $_SERVER["REQUEST_URI"]);
exit();
}
}else{
if($_SERVER["HTTPS"] == "on"){
header("HTTP/1.1 301 Moved Permanently");
header("Location: http://" . $_SERVER["SERVER_NAME"] . $_SERVER["REQUEST_URI"]);
exit();
}
}
ini_set("session.cookie_domain", "domain.com");
session_start();
?>
This is bo_session_check.php
if(isset($_SESSION['agreed']) && $_SESSION['agreed']!="yes" && $_SESSION['admin']!="yes"){
/*
DEPRECIATED
header("location: bo_terms.php");
exit();
*/
$_SESSION['agreed']="yes";
}elseif(isset($_SESSION['user_id']) && $_SESSION['user_id']!=""){
/*ALL GOOD*/
}else{
/*YOU GOTTA GO*/
header("location: login.php");
exit();
}
?>
Here is the PHP Session Info

Answer 1

Since $_SESSION is handled server-side -- this is going to mean that cookies are disabled in IE8 -

Answer 2

You have session.use_only_cookies = On, which is fine, but just be aware that anyone with cookies turned off will fail to load your site properly.
However, this is not what is causing the issue.
From other StackOverflow answer:
Try putting [PHP code below] prior to starting the session - this would ensure that the session cookie will not expire until the browser is closed.
session_set_cookie_params(0);
Hope this helps solve your problem. Worst case scenario, pass the SESSION ID (SID) through the URLs in between page loads and redirects. Refer to this page in the PHP Manual on passing Session IDs. You would have to do this through the Location: http://URL that you have.