diff --git a/include/admin/maintenance.inc.php b/include/admin/maintenance.inc.php
index a05ea671..4f864348 100644
--- a/include/admin/maintenance.inc.php
+++ b/include/admin/maintenance.inc.php
@@ -8,6 +8,18 @@ include S9Y_INCLUDE_PATH . 'include/admin/import.inc.php';
 $data['importMenu'] = ob_get_contents();
 ob_end_clean();
 
+if ($_POST['adminAction'] == "maintenanceMode") {
+    if (serendipity_db_bool(serendipity_get_config_var("maintenanceMode", false)) === true) {
+        serendipity_set_config_var("maintenanceMode", false);
+    } else {
+        serendipity_set_config_var("maintenanceMode", true);
+        # after the specified time, given in hours from now, we want the maintenance mode to not be active anymore.
+        # This prevents users from logging themselves out.
+        $activeTill = time() + ($_POST['hours'] * 3600);
+        serendipity_set_config_var("maintenanceModeEnd", $activeTill);
+    }
+}
+
 switch($serendipity['GET']['adminAction']) {
     case 'integrity':
         $data['action'] = "integrity";
@@ -32,6 +44,9 @@ switch($serendipity['GET']['adminAction']) {
         break;
 }
 
+$data['maintenance_mode'] = serendipity_db_bool(serendipity_get_config_var("maintenanceMode", false));
+$data['maintenance_mode_end'] = strftime('%d.%m.%y %T', serendipity_get_config_var("maintenanceModeEnd"));
+$data['maintenance_mode_active'] = $data['maintenance_mode'] && time() < serendipity_get_config_var("maintenanceModeEnd", 0);
 echo serendipity_smarty_show('admin/maintenance.inc.tpl', $data);
 
 /* vim: set sts=4 ts=4 expandtab : */
diff --git a/serendipity_config.inc.php b/serendipity_config.inc.php
index 3a9e1dcf..4476683a 100644
--- a/serendipity_config.inc.php
+++ b/serendipity_config.inc.php
@@ -421,6 +421,22 @@ $serendipity['permissionLevels'] = array(USERLEVEL_EDITOR => USERLEVEL_EDITOR_DE
                                          USERLEVEL_CHIEF => USERLEVEL_CHIEF_DESC,
                                          USERLEVEL_ADMIN => USERLEVEL_ADMIN_DESC);
 
+// Some stuff...
+if (!isset($_SESSION['serendipityAuthedUser'])) {
+    $_SESSION['serendipityAuthedUser'] = false;
+}
+
+if (isset($_SESSION['serendipityUser'])) {
+    $serendipity['user']  = $_SESSION['serendipityUser'];
+}
+
+# && maintenanceMode is on
+//if ( {
+if (($_SESSION['serendipityAuthedUser'] === false) && (serendipity_db_bool(serendipity_get_config_var("maintenanceMode", false)) === true) && time() < serendipity_get_config_var("maintenanceModeEnd", 0)) {
+    header('HTTP/1.1 503 Service Unavailable');
+    serendipity_die("Maintenance mode is on, please check back later");
+}
+
 // Redirect to the upgrader
 if (IS_up2date === false && !defined('IN_upgrader')) {
     if (preg_match(PAT_CSS, $_SERVER['REQUEST_URI'], $matches)) {
@@ -447,15 +463,6 @@ if (isset($serendipity['GET']['searchTerm'])) {
     $serendipity['GET']['searchTerm'] = (is_string($serendipity['GET']['searchTerm']) ? serendipity_specialchars(strip_tags($serendipity['GET']['searchTerm'])) : '');
 }
 
-// Some stuff...
-if (!isset($_SESSION['serendipityAuthedUser'])) {
-    $_SESSION['serendipityAuthedUser'] = false;
-}
-
-if (isset($_SESSION['serendipityUser'])) {
-    $serendipity['user']  = $_SESSION['serendipityUser'];
-}
-
 if (isset($_SESSION['serendipityEmail'])) {
     $serendipity['email'] = $_SESSION['serendipityEmail'];
 }
diff --git a/templates/2k11/admin/maintenance.inc.tpl b/templates/2k11/admin/maintenance.inc.tpl
index 79ca2c41..120dd309 100644
--- a/templates/2k11/admin/maintenance.inc.tpl
+++ b/templates/2k11/admin/maintenance.inc.tpl
@@ -92,6 +92,26 @@
     </section>
 {/if}
 
+{if 'siteConfiguration'|checkPermission || 'blogConfiguration'|checkPermission}
+    <section id="maintenance_mode" class="equal_heights quick_list">
+        <h3>{$CONST.MAINTENANCE_MODE}</h3>
+
+        <form method="POST" target="?">
+            <input type="hidden" name="adminAction" value="maintenanceMode"/>
+            <p>Activate maintenance mode to prevent access from users that are not logged in.</p>
+            {if $maintenance_mode_active}
+                Will be active till: {$maintenance_mode_end}
+                <button type="submit">Deactivate</button>
+            {else}
+                <label>How many hours shall it be active?</label>
+                <input type="number" name="hours" value="1"/>
+                <button type="submit">Activate</button>
+            {/if}
+        </form>
+       
+    </section>
+{/if}
+
 {serendipity_hookPlugin hook="backend_maintenance" hookAll="true"}
 
 </div>
\ No newline at end of file