diff --git a/jupyter_client/manager.py b/jupyter_client/manager.py
index a215393c..f1bc26d7 100644
--- a/jupyter_client/manager.py
+++ b/jupyter_client/manager.py
@@ -183,6 +183,8 @@ def kernel_spec(self) -> t.Optional[kernelspec.KernelSpec]:
         return self._kernel_spec
 
     cache_ports: Bool = Bool(
+        False,
+        config=True,
         help="True if the MultiKernelManager should cache ports for this KernelManager instance"
     )