diff --git a/py-kms/pykms_Server.py b/py-kms/pykms_Server.py
index cbe96a8..71893f0 100755
--- a/py-kms/pykms_Server.py
+++ b/py-kms/pykms_Server.py
@@ -212,7 +212,7 @@ def run(self):
         'reuse'      : {'help' : 'Do not allows binding / listening to the same address and port. Reusing port is activated by default.', 'def' : True,
                         'des': "reuse"},
         'dual'       : {'help' : 'Allows listening to an IPv6 address also accepting connections via IPv4. Deactivated by default.',
-                        'def' : True, 'des': "dual"}
+                        'def' : False, 'des': "dual"}
         }
 
 def server_options():