Merge pull request #18444 from netbox-community/18433-fix-macaddress-primary-for-interface

Fixes: #18433 - Fix missing is_primary property on MACAddress model

netbox/dcim/models/devices.py

@@ -1531,6 +1531,13 @@ class MACAddress(PrimaryModel):
         self._original_assigned_object_id = self.__dict__.get('assigned_object_id')
         self._original_assigned_object_type_id = self.__dict__.get('assigned_object_type_id')
 
+    @cached_property
+    def is_primary(self):
+        if self.assigned_object and hasattr(self.assigned_object, 'primary_mac_address'):
+            if self.assigned_object.primary_mac_address and self.assigned_object.primary_mac_address.pk == self.pk:
+                return True
+        return False
+
     def clean(self, *args, **kwargs):
         super().clean()
         if self._original_assigned_object_id and self._original_assigned_object_type_id: