To use Active Directory to authenticate administrators, which server profile is required in the authentication profile?

"Domain controller" describes the role of a server running Active Directory, not an authentication protocol or server profile type.

TACACS+ is a proprietary Cisco protocol primarily used for device administration authentication and authorization, not directly for Active Directory administrator authentication.

Active Directory uses LDAP (Lightweight Directory Access Protocol) for directory services, including user authentication and authorization. Therefore, to authenticate administrators against Active Directory, an LDAP server profile must be configured and selected in the authentication profile on the Palo Alto Networks firewall.

RADIUS is a common protocol for network access authentication, often used with network devices, but Active Directory itself primarily uses LDAP for its authentication queries.