title: PHP session variables not being maintaned
body: <p>I have an application that has been working with session variables no problem. I start the session before the headers on every page that uses when, it has been fine then it seems all of a sudden I'm getting an undefined index error when I navigate to a page other than the one that sets up the session variables. <strong>But only on some browsers</strong>. Sometimes sessions are maintained and sometimes they aren't.</p>
  
  <p>It seems that cookies aren't being stored some of the time. I've done checks using different browsers and sometimes cookies are stored and sometimes not. </p>
  
  <p>I did an experiment. I was using firefox to use to app and I was keeping an eye on the tmp folder where the sessions are stored. I cleaned it out. Using firefox I started using the app, using all the pages that sessions were in use and at the end I checked the tmp folder and it had one session file in there.</p>
  
  <p>Did the exact same with internet explorer and there are now 7 different session files. </p>
  
  <p>I'm using PHP 5.3.0 with the WAMP stack. Apache 2.2.11. Session support is enabled in my phpinfo().</p>
  
  <p>I call a var dump on the first page and it prints out the session data. On any subsequent pages the session variable is empty.</p>
  
  <pre><code>&lt;?php var_dump($_SESSION); ?&gt;
  
  array(0){}
  </code></pre>
  
  <p>Can anyone help me figure out a solution to this?</p>
  
  <p><strong>UPDATE - PHP INI SESSION settings</strong> </p>
  
  <pre><code>Directive        Local Value     Master Value
  session.auto_start Off           Off 
  session.bug_compat_42 On         On 
  session.bug_compat_warn On       On 
  session.cache_expire 180         180 
  session.cache_limiter nocache    nocache 
  session.cookie_domain 82.68.26.169   82.68.26.169 
  session.cookie_httponly Off      Off 
  session.cookie_lifetime 0        0 
  session.cookie_path /            / 
  session.cookie_secure Off        Off 
  session.entropy_file no value    no value 
  session.entropy_length 0         0 
  session.gc_divisor 1000 1000 
  session.gc_maxlifetime 1440      1440 
  session.gc_probability 1         1 
  session.hash_bits_per_character 5 5 
  session.hash_function 0 0 
  session.name PHPSESSID           PHPSESSID 
  session.referer_check no value   no value 
  session.save_handler files       files 
  session.save_path c:/wamp/tmp    c:/wamp/tmp 
  session.serialize_handler php    php 
  session.use_cookies On           On 
  session.use_only_cookies On      On 
  session.use_trans_sid 0          0 
  </code></pre>
  
  <p><strong>UPDATE - Solution</strong></p>
  
  <p>Because my app was using iframes pulling in pages from another domain (which i created) the cookies i was trying to set were being blocked. Setup a P3P header and the problem seems to be solved!</p>