DNS requirements for installing Active Directory

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

DNS requirements for installing Active Directory

When you install Active Directory on a member server, the member server is promoted to a domain controller. Active Directory uses DNS as the location mechanism for domain controllers, enabling computers on the network to obtain IP addresses of domain controllers.

During the installation of Active Directory, the service (SRV) and address (A) resource records are dynamically registered in DNS, which are necessary for the successful functionality of the domain controller locator (Locator) mechanism.

To find domain controllers in a domain or forest, a client queries DNS for the SRV and A DNS resource records of the domain controller, which provide the client with the names and IP addresses of the domain controllers. In this context, the SRV and A resource records are referred to as Locator DNS resource records.

When adding a domain controller to a forest, you are updating a DNS zone hosted on a DNS server with the Locator DNS resource records and identifying the domain controller. For this reason, the DNS zone must allow dynamic updates (RFC 2136) and the DNS server hosting that zone must support the SRV resource records (RFC 2782) to advertise the Active Directory directory service. For more information about RFCs, see DNS RFCs.

If the DNS server hosting the authoritative DNS zone is not a server running Windows 2000 or Windows Server 2003, contact your DNS administrator to determine if the DNS server supports the required standards. If the server does not support the required standards, or the authoritative DNS zone cannot be configured to allow dynamic updates, then modification is required to your existing DNS infrastructure.

For more information, see Checklist: Verifying DNS before installing Active Directory and Using the Active Directory Installation Wizard.


  • The DNS server used to support Active Directory must support SRV resource records for the Locator mechanism to function. For more information, see Managing resource records.

  • It is recommended that the DNS infrastructure allows dynamic updates of Locator DNS resource records (SRV and A) before installing Active Directory, but your DNS administrator may add these resource records manually after installation.

    After installing Active Directory, these records can be found on the domain controller in the following location: systemroot\System32\Config\Netlogon.dns