diff --git a/freeradius/auth.py b/freeradius/auth.py
index d602e3db..159dfbd8 100644
--- a/freeradius/auth.py
+++ b/freeradius/auth.py
@@ -161,7 +161,7 @@ def register_mac(data, machine, conn):
         return
     mac = mac.decode('ascii', 'ignore').replace('"','')
     try:
-        mac = lc_ldap.crans_utils.format_mac(value)
+        mac = lc_ldap.crans_utils.format_mac(mac).lower()
     except:
         radiusd.radlog(radiusd.L_ERR, 'Cannot format MAC !')
         return
@@ -250,6 +250,7 @@ def post_auth(data, conn):
 
     if not items:
         decision = 'accueil', 'Machine inconnue'
+        return radiusd.RLM_MODULE_NOTFOUND # TODO faire un truc plus propre
 
     machine = items[0]
     proprio = machine.proprio()