What is the purpose of a Read-Only Domain Controller?

The purpose of a Read-Only Domain Controller (RODC) is specifically to provide read-only access to domain data. This function is essential in scenarios where security and availability are prioritized, particularly in remote or branch office environments. An RODC holds a copy of the Active Directory data but does not permit changes to this data. This means that while it can respond to authentication and directory service requests, it prevents unauthorized modifications and ensures that any potential security risks associated with sensitive domain data are minimized.

By allowing only read access, organizations can deploy RODCs in locations where physical security may be a concern. This setup effectively mitigates the risk of an attacker gaining full control over the domain from a less secure site, as any changes to the directory would need to be made on a regular Domain Controller instead.

This function is distinct from managing connections, hosting applications, or handling system updates, which fall under different operational roles within an IT infrastructure. Each of those activities serves different purposes and does not directly relate to the specific capabilities and security features provided by a Read-Only Domain Controller.