diff --git a/audit.php b/audit.php
index a97003f2..bf5bd26f 100644
--- a/audit.php
+++ b/audit.php
@@ -196,7 +196,7 @@ function entropy($str) {
      **/
     function mac($addr) {
         return (bool)filter_var($addr,FILTER_VALIDATE_MAC)
-            || !preg_match('/^([0-9a-f]{2}:){3}ff:fe(:[0-9a-f]{2}){3}$/i', $addr);
+            || preg_match('/^([0-9a-f]{2}:){3}ff:fe(:[0-9a-f]{2}){3}$/i', $addr);
     }
 
 }