diff --git a/freeradius/auth.py b/freeradius/auth.py
index 39deccc5..a4f23a2f 100644
--- a/freeradius/auth.py
+++ b/freeradius/auth.py
@@ -151,6 +151,7 @@ def register_mac(auth_data, machine, conn):
         radiusd.radlog(radiusd.L_INFO, 'Registering mac %s' % mac)
         machine['macAddress'] = mac
         machine.history_add(u'auth.py', u'macAddress (<automatique> -> %s)' % mac)
+        machine.validate_changes()
         machine.save()
         radiusd.radlog(radiusd.L_INFO, 'Mac set')
         radiusd.radlog(radiusd.L_INFO, 'Triggering komaz')