PDC AND BDC IN DIFFERNET LOCATION

Question

Is it possible to configure PDC and BDC in different location? if possible then how does it will work?

Answer 1

Hello,

Thank you for posting in Q&A forum.

Yes, PDC (Primary Domain Controller) and BDC (Backup Domain Controller) can be configured in different locations. They can be in the same site or in different sites. Communication between the PDC and BDC is through the Active Directory replication protocol.

However, in modern Active Directory environments, the concepts of PDC (Primary Domain Controller) and BDC (Standby Domain Controller) are no longer used. Instead, all domain controllers are equal and jointly manage the Active Directory database.

Old PDC and BDC models:

In earlier Windows NT domains, there was a primary domain controller (PDC) and one or more alternate domain controllers (BDCs).

The PDC is responsible for handling user authentication requests, password changes, and other domain operations.

The BDC is a copy of the PDC, but read-only. They are synchronized periodically after the PDC update.

Modern Active Directory:

Active Directory (AD) is a distributed database that contains domain controllers (DCs).

All DCs store the same AD database, with no distinction between primary or standby.

The data synchronization between the DCs is real-time, rather than periodic synchronization like PDC and BDC.

The old PDC and BDC model workflow was as follows:

Installation and configuration: Start by installing and configuring the PDC somewhere. Then, install the BDC in another physical location and join it to the same domain.

Replication: Once the BDC joins the domain, it automatically starts synchronizing the AD database with the PDC. This replication is asynchronous and can be optimized based on network conditions and site topology.

Failover: If the PDC fails, the BDC can be promoted to the primary domain controller and take over the role of the PDC to ensure uninterrupted domain services. This process has different processes in different versions of Windows Server, but the basic principle is to ensure that at least one domain controller is able to respond to user logon requests and resource access verification.

Recovery & Resynchronization: When the original PDC is repaired, it can rejoin the domain as a BDC or, if appropriate, reconfigure the primary domain controller and synchronize data with the existing primary domain controller (the previously promoted BDC).

Recommended Reference Links: Add a Backup Domain Controller to an existing AD Domain (thesolving.com)

I hope the information above is helpful.

Best Regards,

Yanhong Liu

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