It depends if the server is a domain controller or not. If it's not a domain controller, all users have admin rights, who are members of the local Administrators Group (see Computer Management > Local Users and Groups - Administrators.)
If the server is a domain controller, users who a members of the Administrators Group or the Domain Admins Group or the Enterprise Admins group (if there is a forest of domains), have admin rights on that particular server. The Domain Admins Group is by default member of all Administrator groups on all computers that are in the domain.
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.
Server local groups (such as a server's Administrators group) are not available via AD. You have to look in the Administrators group on the server. This post has a script that will enumerate the local admin group remotely.
If the box is a member server check in the local Administrators group on the server. If it's a Domain Controller check in both Administrators and Domain Admins in Active Directory Users and Computers tool.
It depends if the server is a domain controller or not. If it's not a domain controller, all users have admin rights, who are members of the local Administrators Group (see Computer Management > Local Users and Groups - Administrators.)
If the server is a domain controller, users who a members of the Administrators Group or the Domain Admins Group or the Enterprise Admins group (if there is a forest of domains), have admin rights on that particular server. The Domain Admins Group is by default member of all Administrator groups on all computers that are in the domain.
Here you can find a list of Active Directory built-in Groups and Accounts:
You could also run the 'gpresult' command while logged onto the server as the user in question. (if that is possible in this case)
You'll get a nice list of the groups they're a member of, including BUILTIN\Administrators.
Server local groups (such as a server's Administrators group) are not available via AD. You have to look in the Administrators group on the server. This post has a script that will enumerate the local admin group remotely.
If the box is a member server check in the local Administrators group on the server. If it's a Domain Controller check in both Administrators and Domain Admins in Active Directory Users and Computers tool.