actually this behaviour is totally correct. The switch tries to authenticate a client, when the switch learns the clients MAC address. As the MAC address is extracted from the ethernet header there must be some packages sent from the client in order to do so. If the client is quiet, the switch cannot do anything about it.
Matthias Nagel
Willy-Andreas-Allee 1, Zimmer 506
76131 Karlsruhe
Telefon: +49-721-8695-1506
Mobil: +49-151-15998774
ICQ: 499797758
Skype: nagmat84