diff --git a/machines/models.py b/machines/models.py
index 29e126aa..f7ef3681 100644
--- a/machines/models.py
+++ b/machines/models.py
@@ -3,7 +3,7 @@ from django.db.models.signals import post_save, post_delete
 from django.dispatch import receiver
 from django.forms import ValidationError
 from macaddress.fields import MACAddressField
-from netaddr import EUI
+from netaddr import mac_bare, EUI
 from django.core.validators import MinValueValidator,MaxValueValidator
 
 from re2o.settings import MAIN_EXTENSION
@@ -86,6 +86,9 @@ class Interface(models.Model):
         user = self.machine.user
         return machine.active and user.has_access()
 
+    def mac_bare(self):
+        return str(EUI(self.mac_address, dialect=mac_bare)).lower()
+
     def clean(self, *args, **kwargs):
         self.mac_address = str(EUI(self.mac_address)) or None
         if self.ipv4:
diff --git a/users/models.py b/users/models.py
index 5a9b326f..c966f5c0 100644
--- a/users/models.py
+++ b/users/models.py
@@ -264,7 +264,7 @@ class User(AbstractBaseUser):
         if access_refresh:
             user_ldap.dialupAccess = str(self.has_access())
         if mac_refresh:
-            user_ldap.macs = [inter.mac_address for inter in Interface.objects.filter(machine=Machine.objects.filter(user=self))]
+            user_ldap.macs = [inter.mac_bare() for inter in Interface.objects.filter(machine=Machine.objects.filter(user=self))]
         user_ldap.save()
 
     def ldap_del(self):