diff --git a/nest/config.Y b/nest/config.Y
index 75728e0d..07e1af31 100644
--- a/nest/config.Y
+++ b/nest/config.Y
@@ -216,7 +216,7 @@ limit_spec:
      l->action = $2;
      $$ = l;
    }
- | OFF { $$ = 0; }
+ | OFF { $$ = NULL; }
  ;
 
 rtable: