diff --git a/src/opnsense/mvc/app/models/OPNsense/Base/FieldTypes/PortField.php b/src/opnsense/mvc/app/models/OPNsense/Base/FieldTypes/PortField.php
index 9323fd36a..74eea2090 100644
--- a/src/opnsense/mvc/app/models/OPNsense/Base/FieldTypes/PortField.php
+++ b/src/opnsense/mvc/app/models/OPNsense/Base/FieldTypes/PortField.php
@@ -107,7 +107,7 @@ class PortField extends BaseField
             self::$internalOptionList = array("any") + self::$wellknownservices;
 
             for ($port=1; $port <= 65535; $port++) {
-                self::$internalOptionList[] = $port;
+                self::$internalOptionList[] = (string)$port;
             }
         }
     }