Data ONTAP 8 and later
This article describes the procedure on how to determine if a Windows Domain Controller is a suitable NTP server for Data ONTAP 8.
Data ONTAP 8 uses NTP for time synchronization. It requires a more accurate time source than that provided by Windows DC by default (10 seconds). Therefore, using Windows DCs, Data ONTAP 8 loses time synchronization. If the time difference between the storage system and the DC is greater than 5 minutes, a CIFS authentication failure will occur.