diff --git a/src/Commands/RegisterCommand.php b/src/Commands/RegisterCommand.php
index 075451b..4352df3 100644
--- a/src/Commands/RegisterCommand.php
+++ b/src/Commands/RegisterCommand.php
@@ -47,6 +47,14 @@ public function execute() : ServerResponse
                 'text'    => "*error:* server '$uid' not found",
                 'parse_mode' => 'Markdown'
             ]);
+        } 
+        else if ($id_server == -1)
+        {
+            return Request::sendMessage([
+                'chat_id' => $chat_id,
+                'text'    => "*error:* '$uid' is not in a valid format.",
+                'parse_mode' => 'Markdown'
+            ]);
         }
 
         echo "here now\n";
diff --git a/src/bot.php b/src/bot.php
index ba02d04..612e44b 100644
--- a/src/bot.php
+++ b/src/bot.php
@@ -38,6 +38,12 @@ class PimOnlineBot
      */
     private $base_url;
     
+    /**
+     * Minimum interval in seconds before updating the database for an online host.
+     * @var int
+     */
+    const MIN_UPDATE_INTERVAL = 30;
+
     /**
      * Init a PimOnlineBot
      */
@@ -71,6 +77,12 @@ public function pdo()
         return $this->pdo;
     }
     
+    private function is_valid_uuid($uuid)
+    {
+        $pattern = '/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i';
+        return preg_match($pattern, $uuid) === 1;
+    }
+    
     private function init_db($mysql_credentials)
     {
         $dsn = 'mysql:host=' . $mysql_credentials['host'] . ';dbname=' . $mysql_credentials['database'];
@@ -127,6 +139,11 @@ public function online($uid)
             $id = $row['id'];
             $past = $row['now'];
             $alarm = $row['alarm'];
+            $currentTime = time();
+
+            if (!$alarm && ($currentTime - $past) < self::MIN_UPDATE_INTERVAL) {
+                return; 
+            }
             
             $sql = "UPDATE `ob_online` SET `now` = :now, `past` = :past, `alarm` = :alarm WHERE `id` = :id";
             $statement = $pdo->prepare($sql);
@@ -194,6 +211,11 @@ public function udpate_db()
     
     public function id_server($uid)
     {
+        if (!$this->is_valid_uuid($uid))
+        {
+            echo "Invalid UUID format rejected: " . $uid;
+            return -1;
+        }
         $pdo = $this->pdo();
         $sql = "SELECT * FROM `ob_online` where uid=:uid order by id DESC limit 1";
         $statement = $pdo->prepare($sql);