Kohana 3 AUTH loggin issues on specific machines

I have used Kohana on several projects now, as well as its included Authentication module with absolutely zero issues... until this particular client.

At first they could not log in to the site on an XP machine using IE8. I did some digging and ended up adding this config file to application/config/session.php

<?php defined('SYSPATH') OR die('No direct access allowed.');

/**
 * @package Session
 *
 * Session driver name.
 */
//$config['driver'] = 'native';

/**
 * Number of page loads before the session id is regenerated.
 * A value of 0 will disable automatic session id regeneration.
 */
//$config['regenerate'] = 0;


// KLUDGE: Windows XP SP3 running IE-7 and 8
// http://bit.ly/gPcV67
//$config['validate'] = 'ip_address';

    return array(
      'cookie' => array(
          'name' => 'session_cookie',
          'encrypted' => TRUE,
          'lifetime' => 43200,
      ),
      'native' => array(
          'name' => 'session_native',
          'encrypted' => TRUE,
          'lifetime' => 43200,
      ),
      'database' => array(
          'name' => 'session_database',
          'group' => 'default',
          'table' => 'sessions',
      ),
  );

?>

This worked for IE8 on the WinXP Machine

Now they have a laptop with Win7 that can not login with IE9 or Firefox 4. I installed Chrome on the machine to make it workable till I could find the time to look into this further (Chrome worked fine while I was in front of the machine). Today however I got a whole series of really piss开发者_运维问答ed off emails claiming they could not get into the system again.

I can not reproduce this problem on any of my machines or browsers. I am stumped, and I do not have a way to test changes I make.

Please Please Please HELP! Thank you, -David

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Sounds like a server issue to me, probably at the time of their login something denied their access (session not written?). I'd try with memcached or database sessions.