What Is AD Connect
AD Connect, formally Azure AD Connect and now Microsoft Entra Connect, is the Microsoft tool that synchronizes your on-premises Active Directory with Microsoft Entra ID in the cloud. It keeps users, groups, and (optionally) passwords consistent across both environments, so people sign in once with the same identity whether they are reaching an on-premises file server or a cloud app like Microsoft 365.
Most established organizations are not purely cloud or purely on-premises; they are hybrid. They have years of investment in on-premises Active Directory, plus a growing dependence on Microsoft 365 and other cloud services. AD Connect is the bridge that makes that hybrid reality work as one identity system rather than two disconnected ones. Configured correctly, it delivers seamless single sign-on, consistent access, and a single source of truth for identity. Configured poorly, it creates sync errors, duplicate accounts, and security gaps. ARC implements and manages AD Connect so hybrid identity is reliable, secure, and ready for an eventual move to the cloud.