DC Locator

The process that a client computer/application uses to contact the closest available domain controller within an AD Domain is called the “DC Locator Process”. DC Locator is an algorithm that runs in the context of the Net Logon service on the client computer. It relies on DNS resolution and AD sites and subnets configuration for the identification.

DC locater is critical because:

• Sites are often linked by slow network connections which might cause slowness with cross-site communication with Active Directory.
• It minimizes the impacts when a Domain Controller is not available.
• It reduces unnecessary network traffic between sites by locating the closest Domain Controller.

Ref: https://servergurunow.wordpress.com/2017/10/14/dc-locator-process-2/#:~:text=The%20process%20that%20a%20client,service%20on%20the%20client%20computer.