Depende se o servidor é um controlador de domínio ou não. Se não for um controlador de domínio, todos os usuários têm direitos de administrador, que são membros do Grupo de Administradores local (consulte Gerenciamento do Computador > Usuários e Grupos Locais - Administradores.)
Se o servidor for um controlador de domínio, os usuários pertencentes ao Grupo de Administradores ou o Grupo de Administradores do Domínio ou o grupo Administradores Corporativos (se houver uma floresta de domínios), têm direitos de administrador nesse servidor específico. O grupo de administradores do domínio é, por padrão, membro de todos os grupos de administradores em todos os computadores que estão no domínio.
Aqui você pode encontrar uma lista de grupos e contas internos do Active Directory :
Administrators
After the initial installation of the operating system, the only member of the group is the Administrator account. When a computer joins a domain, the Domain Admins group is added to the Administrators group. When a server becomes a domain controller, the Enterprise Admins group also is added to the Administrators group. The Administrators group has built-in capabilities that give its members full control over the system. The group is the default owner of any object that is created by a member of the group.
Domain Admins
A global group whose members are authorized to administer the domain. By default, the Domain Admins group is a member of the Administrators group on all computers that have joined a domain, including the domain controllers. Domain Admins is the default owner of any object that is created in the domain's Active Directory by any member of the group. If members of the group create other objects, such as files, the default owner is the Administrators group.
Enterprise Admins
A group that exists only in the root domain of an Active Directory forest of domains. It is a universal group if the domain is in native mode, a global group if the domain is in mixed mode. The group is authorized to make forest-wide changes in Active Directory, such as adding child domains. By default, the only member of the group is the Administrator account for the forest root domain.