RODC (read-only domain controller)

A read-only domain controller (RODC) is a server that hosts an Active Directory database's read-only partitions and responds to security authentication requests.

RODC, which was designed to be used in branch offices that cannot support their own domain controllers, can be used in a Windows Server 2008 environment or higher.

Before installing RODCs, Microsoft recommends that organizations meet some prerequisites to ensure they work properly, including having a functional AD forest level set at Windows Server 2003 or higher and at least one writeable domain controller deployed on Windows Server 2008 or higher.