Index: branches/5.1.x/core/kernel/session/inp_session.php
===================================================================
diff -u -N -r14241 -r14325
--- branches/5.1.x/core/kernel/session/inp_session.php	(.../inp_session.php)	(revision 14241)
+++ branches/5.1.x/core/kernel/session/inp_session.php	(.../inp_session.php)	(revision 14325)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: inp_session.php 14241 2011-03-16 20:24:35Z alex $
+* @version	$Id: inp_session.php 14325 2011-05-20 08:10:28Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -116,11 +116,14 @@
 			'PortalUserId'	=>	$this->Application->isAdmin ? 0 : USER_GUEST,
 			'Language'		=>	$this->Application->GetDefaultLanguageId(true),
 			'Theme'			=>	$this->Application->GetDefaultThemeId(),
-			'IpAddress'		=>	$_SERVER['REMOTE_ADDR'], // getenv('REMOTE_ADDR') won't work on IIS, so use $_SERVER instead
 			'GroupId'		=>	$this->Application->ConfigValue('User_GuestGroup'),
 			'GroupList'		=>	$this->Application->ConfigValue('User_GuestGroup'),
 		);
 
+		if( isset($_SERVER['REMOTE_ADDR']) ) {
+			$fields_hash['IpAddress'] = $_SERVER['REMOTE_ADDR']; // getenv('REMOTE_ADDR') won't work on IIS, so use $_SERVER instead
+		}
+
 		return array_merge($fields_hash, parent::GetSessionDefaults($session));
 	}