This article is based on an article in the Microsoft TechNet Library and is presented here to enable those outside of Microsoft who are interested and knowledgeable on this topic to improve it. The original article exists on TechNet as Default User Accounts and Groups (http://technet.microsoft.com/en-us/library/bb726980.aspx).

When you install Windows 2000, the operating system installs default users and groups. These accounts are designed to provide the basic setup necessary to grow your network. Three types of default accounts are provided:

• Predefined User and group accounts installed with the operating system.

• Built-In User and group accounts installed with the operating system, applications, and services.

• Implicit Special groups created implicitly when accessing network resources; also known as special identities.

Note: Although you can modify the default users and groups, you can't delete default users and groups created by the operating system. The reason you can't delete these accounts is that you wouldn't be able to re-create them. The SIDs of the old and new accounts wouldn't match, and the permissions and privileges of these accounts would be lost.

Built-In User Accounts

Built-in user accounts have special uses on Windows 2000. While all Windows 2000 systems have one built-in account called LocalSystem, other built-in user accounts may be available.

The LocalSystem Account

LocalSystem is a pseudo-account for running system processes and handling system-level tasks. The account is available on the local system only. You can't change the settings for the LocalSystem account with the user administration tools. Users can't log on to a computer with this account.

Note: While users can't log on to a computer with the LocalSystem account, certain processes can log on using this account. For example, Windows 2000 services can be configured to log on to a computer using the System account. For more information, see the section of Chapter 3 entitled "Managing System Services."

Other Built-In Accounts

When you install add-ons or other applications on a workstation or server, other default accounts may be installed. You can usually delete these accounts.

When you install Internet Information Services, you may find several new accounts, including IUSR_host and IWAM_host, where host is the computer name. The IUSR_host account is the built-in account for anonymous access to Internet Information Services. The IWAM_host account is used by Internet Information Services to start out of process applications. These accounts are defined in Active Directory when they're configured on a domain. However, they're defined as local users when they're configured on a stand-alone server or workstation. Another built-in account that you may see is TSInternetUser. This account is used by Terminal Services.

Predefined User Accounts

Two predefined user accounts are installed with Windows 2000—Administrator and Guest. With workstations and member servers, predefined accounts are local to the individual system they're installed on.

Predefined accounts have counterparts in Active Directory. These accounts have domain-wide access and are completely separate from the local accounts on individual systems.

The Administrator Account

Administrator is a predefined account that provides complete access to files, directories, services, and other facilities. You can't delete or disable this account. In Active Directory, the Administrator account has domain-wide access and privileges. Otherwise, the Administrator account generally has access only to the local system. Although files and directories can be protected from the Administrator account temporarily, the Administrator account can take control of these resources at any time by changing the access permissions.

Tip To prevent unauthorized access to the system or domain, be sure to give the account an especially secure password. Also, because this is a known Windows 2000 account, you may want to rename the account as an extra security precaution.

In most instances you won't need to change the basic settings for this account. However, you may need to change its advanced settings, such as membership in particular groups. By default, the Administrator account for a domain is a member of these groups: Administrators, Domain Admins, Domain Users, Enterprise Admins, Schema Admins, and Group Policy Creator Owners. You'll find more information on these groups in the next section.

Real World In a domain environment, you'll use the local Administrator account primarily to manage the system when you first install it. This allows you to set up the system without getting locked out. You probably won't use the account once the system has been installed. Instead, you'll probably want to make your administrators members of the Administrators group. This ensures that you can revoke administrator privileges without having to change the passwords for all the Administrator accounts.

For a system that's part of a workgroup where each individual computer is managed separately, you'll typically rely on this account anytime you need to perform your system administration duties. Here, you probably won't want to set up individual accounts for each person who has administrative access to a system. Instead, you'll use a single Administrator account on each computer.

The Guest Account

Guest is designed for users who need one-time or occasional access. While guests have limited system privileges, you should be very careful about using this account. Whenever you use this account, you open the system to potential security problems. The potential is so great that the account is initially disabled when you install Windows 2000.

Tip If you decide to enable the Guest account, be sure to restrict its use and to change the password regularly. As with the Administrator account, you may want to rename the account as an added security precaution.

Built-In Groups

Built-in groups are installed with all Windows 2000 workstations and servers. Use the built-in groups to grant a user the group's privileges and permissions. You do this by making the user a member of the group. For example, you give a user administrative access to the system by making a user a member of the local Administrators group. You give a user administrative access to the domain by making a user a member of the domain local Administrators group in Active Directory.

The availability of a specific built-in group depends on the current system configuration. Use Table 7-2 to determine the availability of the various built-in groups. Each of these groups is discussed later in the chapter.

Table 7-2 Availability of Built-In Groups Based on the Type of Network Resource

Predefined Groups

Predefined groups are installed with Active Directory domains. Use these groups to assign additional permissions to users, computers, and other groups. You do this by making the user a member of the group. Predefined groups include domain local, global, and universal groups. The availability of a specific built-in group depends on the domain configuration.

Use Table 7-3 to determine the availability of the various predefined groups. Key predefined groups are discussed later in this chapter.

Note: The group scope for Enterprise Admins and Schema Admins can be either universal or global, depending on the operations mode. In mixed mode, these are global groups. In native mode, these are universal groups.

Table 7-3 Availability of Predefined Groups Based on Domain Configuration

Implicit Groups and Special Identities

In Windows NT implicit groups were assigned implicitly during logon and were based on how a user accessed a network resource. For example, if a user accessed a resource through interactive logon, the user was automatically a member of the implicit group called Interactive. In Windows 2000, the object-based approach to the directory structure changes the original rules for implicit groups. While you still can't view the membership of special identities, you can grant membership in implicit groups to users, groups, and computers.

To reflect the new role, implicit groups are also referred to as special identities. A special identity is a group whose membership can be set implicitly, such as during logon, or explicitly through security access permissions. As with other default groups, the availability of a specific implicit group depends on the current configuration. Use Table 7-4 to determine the availability of the various implicit groups. Implicit groups are discussed later in this chapter.

Table 7-4 Availability of Implicit Groups Based on the Type of Network Resource

Account Capabilities

When you set up a user account, you can grant the user specific capabilities. You generally assign these capabilities by making the user a member of one or more groups, thus giving the user the capabilities of these groups. You then assign additional capabilities by making a user a member of the appropriate groups. You withdraw capabilities by removing group membership.

In Windows 2000, you can assign various types of capabilities to an account. These capabilities include

• Privileges A type of user right that grants permissions to perform specific administrative tasks. You can assign privileges to both user and group accounts. An example of a privilege is the ability to shut down the system.

• Logon rights A type of user right that grants logon permissions. You can assign logon rights to both user and group accounts. An example of a logon right is the ability to log on locally.

• Built-in capabilities A type of user right that is assigned to groups and includes the automatic capabilities of the group. Built-in capabilities are predefined and unchangeable, but they can be delegated to users with permission to manage objects, organizational units, or other containers. An example of a built-in capability is the ability to create, delete, and manage user accounts. This capability is assigned to administrators and account Operators. Thus, if a user is a member of the Administrators group, the user can create, delete, and manage user accounts.

• Access permissions A type of user right that defines the operations that can be performed on network resources. You can assign access permissions to users, computers, and groups. An example of an access permission is the ability to create a file in a directory. Access permissions are discussed in Chapter 13.

As an administrator, you'll be dealing with account capabilities every day. To help track built-in capabilities, refer to the sections that follow. Keep in mind that while you can't change the built-in capabilities of a group, you can change the default rights of a group. For example, an administrator could revoke network access to a computer by removing a group's right to access the computer from the network.

Privileges

A privilege is a type of user right that grants permissions to perform a specific administrative task. You assign privileges through group policies, which can be applied to individual computers, organizational units, and domains. Although you can assign privileges to both users and groups, you'll usually want to assign privileges to groups. In this way, users are automatically assigned the appropriate privileges when they become members of a group. Assigning privileges to groups also makes it easier to manage user accounts.

Table 7-5 provides a brief summary of each of the privileges that can be assigned to users and groups. To learn how to assign privileges, see Chapter 8.

Table 7-5 Windows 2000 Privileges for Users and Groups

Logon Rights

A logon right is a type of user right that grants logon permissions. You can assign logon rights to both user and group accounts. As with privileges, you assign logon rights through group policies and you'll usually want to assign logon rights to groups rather than individual users.

Table 7-6 provides a brief summary of each of the logon rights that can be assigned to users and groups. To learn how to assign logon rights, see Chapter 8

Table 7-6 Windows 2000 Logon Rights for Users and Groups

Built-In Capabilities for Groups in Active Directory

The built-in capabilities for groups in Active Directory are fairly extensive. The tables that follow summarize the most common capabilities that are assigned by default. Table 7-7 shows the default user rights for groups in Active Directory domains. This includes both privileges and logon rights. Note that any action that's available to the Everyone group is available to all groups, including the Guests group. This means that although the Guests group doesn't have explicit permission to access the computer from the network, Guests can still access the system because the Everyone group has this right.

Table 7-7 Default User Rights for Groups in Active Directory

Table 7-8 shows the default user rights for local groups on member servers and workstations. Again, this includes both privileges and logon rights. Note that on these systems, Power Users have privileges that normal users don't.

Table 7-8 Default User Rights for Local Groups

Table 7-9 summarizes capabilities that can be delegated to other users and groups. As you study the table, note that restricted accounts include the Administrator user account, the user accounts of administrators, and the group accounts for Administrators, Server Operators, Account Operators, Backup Operators, and Print Operators. Because these accounts are restricted, Account Operators can't create or modify them.

Table 7-9 Other Capabilities for Built-In and Local Groups