Which authentication protocols does Windows Server 2012 natively support?

Windows Server 2012 natively supports NTLM (NT LAN Manager) and Kerberos as its primary authentication protocols. NTLM is an older protocol that provides authentication for users and systems that rely on pre-Windows 2000 technologies, while Kerberos is a more modern and secure protocol that has become the standard for authentication in Windows environments, especially in domains.

Kerberos operates using tickets, reducing the need to transmit passwords across the network, thus improving security. It is designed for a client-server model and is used to authenticate users to services without needing to exchange sensitive information. These protocols are fundamental in securing user logins, especially within Windows domains where trust relationships between various systems are needed.

The other options listed do involve authentication mechanisms but either do not natively pertain to Windows Server 2012 or apply to broader standards outside of Windows-specific implementations. For example, LDAP and RADIUS are used for directory services and remote authentication, respectively, but are not core authentication protocols of Windows Server itself. Similarly, SAML and OAuth are modern web-based authentication and authorization frameworks that are outside the traditional realm of Windows native protocols. SHA and MD5 are hashing algorithms used primarily for data integrity and are not authentication protocols.