Event ID 4521 — DNS Server Active Directory Integration

Applies To: Windows Server 2008

You can configure the DNS Server service to use Active Directory Domain Services (AD DS) to store zone data. This makes it possible for the DNS server to rely on directory replication, which enhances security, reliability, and ease of administration.

Event Details

Product: Windows Operating System
ID: 4521
Source: Microsoft-Windows-DNS-Server-Service
Version: 6.0
Message: The DNS server encountered error %1 attempting to load zone %2 from Active Directory. The DNS server will attempt to load this zone again on the next timeout cycle. This can be caused by high Active Directory load and may be a transient condition.


Check the AD DS load

The DNS Server service encountered a delay while loading a zone from Active Directory Domain Services (AD DS). No further action is required if the DNS server started successfully or the zone loaded successfully. Otherwise, diagnose and correct AD DS problems that are causing an excessively high volume of  operations.

For information about troubleshooting AD DS, see Active Directory Troubleshooting Topics (https://go.microsoft.com/fwlink/?LinkId=95789).


Ensure that Event IDs 4523 and 4524 are being logged and that no events in the range 4000 to 4019 appear in the Domain Name System (DNS) event log.

DNS Server Active Directory Integration

DNS Infrastructure