Administering Computer Accounts in Active Directory
Computers, such as workstations and member servers, must be authenticated to access Active Directory resources under Windows Server 2003, just as they must be authenticated under Active Directory in Windows 2000 Server. To become a participant in an Active Directory domain, Windows NT, Windows 2000, Windows XP, and other Windows Server 2003 computers must formally join a domain by establishing a computer account within the domain. Windows 95 and Windows 98 (Windows 9x) computers cannot formally join a domain; however, users can log on to a Windows Server 2003 Active Directory domain and access resources as if it were a Windows NT 4.0 domain under both the Windows 2000 mixed and the Windows 2000 native domain functional levels. Windows Server 2003 domain functional levels are discussed in Chapter 5, "Managing Access to Resources."
The Active Directory Client for Windows 9x and Windows NT 4.0
The Windows 2000 mixed domain functional level supports the NTLM (NT LAN Manager) authentication protocol that is used by Windows NT BDCs to authenticate users and computers. The older LM (LAN Manager) authentication protocol and the NTLM protocol are responsible for authenticating Windows 9x– and Windows NT–based computers. Windows 2000 mixed also supports the newer Kerberos authentication protocol that is used by the Windows 2000 native and the Windows Server 2003 domain functional levels. In addition to Kerberos, the Windows 2000 native and the Windows Server 2003 functional levels support the newer NTLM version 2 (NTLM v2) authentication protocol. Windows 9x computers do not natively support NTLM v2, nor do Windows NT 4.0 computers unless they have Service Pack 4 (SP4) or higher installed. Windows 9x and Windows NT 4.0 computers can natively log on to a Windows Server 2003 Active Directory domain in the following circumstances:
- The Windows Server 2003 domain is set at Windows 2000 mixed and either a PDC emulator or a Windows NT 4.0 BDC is available.
- The Windows Server 2003 domain is set at Windows 2003 interim and either a PDC emulator or a Windows NT 4.0 BDC is available.
To add support for Windows 9x and Windows NT 4.0 computers to access Active Directory resources, you can install the Active Directory client software so that these legacy clients can access resources stored in Windows Server 2003 domains. The Active Directory client software (dsclient.exe) for Windows 9x computers is located on the Windows 2000 Server CD-ROM (it's not on the Windows Server 2003 CD-ROM) in the Clients\Win9x folder. The Windows NT 4.0 version of the Active Directory client is available from Microsoft's website at http://www.microsoft.com/windows2000/server/evaluation/news/
Creating Computer Accounts
You can create computer accounts in one of three ways:
- Log onto each (Windows NT 4.0, Windows 2000, Windows XP, Windows Vista, or Windows Server 2003) computer and join it to the domain.
- Prestage the computer accounts on a DC using the Active Directory Users and Computers (ADUC) MMC snap-in.
- Prestage the computer accounts on a DC using the dsadd.exe command-line utility.
- Prestage the computer accounts on a DC using some other scripted or command-line utility.
For computers running Windows NT, Windows 2000, Windows XP, Windows Vista, and Windows Server 2003, you create accounts for those computers when you join them to the Windows Server 2003 Active Directory domain, provided that computer accounts for those computers have not been prestaged. For example, on a Windows 2000 (Professional or Server) system, you join the computer to a domain by following these steps:
- Double-click the System icon in the Control Panel.
- Click the Network Identification tab from the System Properties window.
- Click the Properties button.
- Click the Domain option button, type in the name of the Active Directory domain that you want to join, and click OK.
- Type in the name and password for a user account in the domain that has administrative-level permission to join computers to this domain and click OK (see Figure 2.3).
Figure 2.3 Joining a Windows 2000 computer to a Windows Server 2003 Active Directory domain.
- Click OK for the Welcome message box that confirms you have successfully joined the computer to the domain.
Troubleshooting Joining a Computer to a Domain
If you have difficulty joining the domain, be sure to check the computer for any physical network connectivity problems. If you verify that the physical network connection is functioning properly, use the TCP/IP ping command at a command prompt window to test the connectivity to a domain controller by pinging the DC's IP address. For example, you can type ping 192.168.0.10 at a command prompt if the DC's IP address is 192.168.0.10. If that works, attempt to ping the DC by its fully qualified domain name (FQDN)—for example, ping dc1.windows2003.local.
Using the FQDN for the DC should uncover a DNS name resolution problem, if one exists. If you simply try to ping the server's NetBIOS or hostname by typing ping DC1, the name could be resolved by a NetBIOS broadcast, making you think that DNS name resolution is not a problem. If pinging the FQDN does not work, you might very well have a DNS name-resolution problem. You should check the computer's DNS server settings as well as the network's DNS setup. Perhaps the computer is not registered with an appropriate DNS server on your network. If you verify that the computer's DNS server settings are pointed to the appropriate DNS server(s), you can remedy a DNS registration issue on Windows 2000/XP/Vista/2003 computers by performing these steps:
- Open a command prompt window.
- Type ipconfig /flushdns and press Enter.
- Type ipconfig /registerdns and press Enter.
- Restart the computer to ensure that these changes take effect.
Prestaging Computer Accounts from the GUI
You can use the ADUC console to view, add, modify, and delete computer accounts, user accounts, and groups from the Windows GUI. On a Windows Server 2003 DC computer, click Start, Administrative Tools, Active Directory Users and Computers to launch the ADUC console. You can also click Start, Run; type dsa.msc; and click OK to run the ADUC console. By creating a computer account in Active Directory before the computer joins the domain, you can determine exactly where in the directory the computer account will be placed. The default location for computers joined to a domain without prestaging is the Computers container. In addition, prestaging computer accounts gives administrators more control over Remote Installation Services (RIS) installations. You can specify that only prestaged computer accounts can be installed via RIS.
For a new Active Directory domain, the default containers are Built-in, Computers, Domain Controllers, Foreign Security Principals, and Users. If you click the ADUC's View menu and select Advanced Features, you can view the advanced containers that are hidden by default. The advanced containers are LostAndFound, NTDS Quotas, Program Data, and System. To create a new computer account in the ADUC, follow these steps:
- Open the ADUC MMC snap-in (console).
- Right-click the container or OU into which you want to place the computer account, select New, and then click Computer.
- Type in the computer name.
- Type in the pre-Windows 2000 computer name, if different from the computer name.
- To change the user or group that has permission to join computers to the domain, click the Change button. The default group is the Domain Admins group: Any member of this group has authority to join computer accounts to the domain.
- If this computer account is a Windows NT computer, mark the Assign This Computer Account as a Pre-Windows 2000 Computer check box.
- If this computer account is for a Windows NT BDC computer, mark the Assign This Computer Account as a Backup Domain Controller check box (see Figure 2.4).
Figure 2.4 Creating a new computer account in ADUC.
- Click Next.
- If you are prestaging the computer account for later installation via RIS, mark the This Is a Managed Computer check box and type in the computer's unique ID (GUID/UUID), referred to as its globally unique identifier or its universally unique identifier. This extra security measure prevents unauthorized RIS client installations because only computers with matching GUIDs are allowed to be installed via RIS when you follow this procedure. You can find the GUID or UUID in the computer's BIOS or by using a third-party software utility (see Figure 2.5).
Figure 2.5 Specifying a computer's GUID for prestaging a computer account.
- Click Next.
- Select an option for specifying the type of RIS server support for this computer account:
- Any Available Remote Installation Server
- The Following Remote Installation Server
- To specify a particular RIS server, select The Following Remote Installation Server option and type in the fully qualified DNS hostname, or click the Search button to locate the server (see Figure 2.6).
Figure 2.6 Specifying the RIS server's name for prestaging a computer account.
- Click Next.
- Click Finish for the New Object-Computer summary window.
Prestaging Computer Accounts from the Command Line
Windows Server 2003 offers several new command-line tools for working with Active Directory. For a detailed list of these commands and their functions, see the section "Using Command-Line Utilities for Active Directory Objects" later in this chapter. You can use the dsadd.exe tool to add Active Directory objects such as computer accounts from any Windows Server 2003 command prompt. With dsadd.exe, you can add one computer account at a time from the command line, or you can redirect standard input for dsadd.exe and use a text file that contains the computer account that you want added. For parameters with embedded spaces, such as names of OUs, surround the DN with quotes. The following two examples in Table 2.1 and in Figure 2.7 demonstrate some of the possibilities and their associated syntax for adding computer accounts via the command line.
Table 2.1. Examples of the dsadd.exe Command
dsadd computer cn=station77,cn=Computers, dc=windows2003,dc=local
Adds a computer account named station77 to Active Directory in the Computers container for the domain named windows2003.local.
dsadd computer "cn=station88,ou=west coast, dc=windows2003,dc=local"
Adds a computer account named station88 to Active Directory in the West Coast OU for the domain named windows2003.local.
Figure 2.7 Adding computer accounts using the dsadd.exe command.
Managing and Troubleshooting Computer Accounts
You can manage problems with computer accounts from the ADUC console. To modify the properties of a computer account, right-click the computer name listed in the ADUC console and select Properties. From the properties sheet, you can make several changes to the account such as trusting the computer for delegation, viewing which operating system the computer is running, adding or removing group memberships, and modifying security permissions and dial-in permissions (see Figure 2.8), among other options.
Figure 2.8 Working with dial-in properties for a computer account.
Administering and Troubleshooting Computer Accounts
You can easily move one or several computer accounts from one container to another container under Windows Server 2003. The ADUC console supports both cut and paste and drag-and-drop functionality by default. You can select one or more computer accounts, right-click the accounts, and select Cut from the right-click menu. Alternatively, you can click and drag one or more selected computer accounts and drop the accounts into a different container. As a third option, you can select one or more computer accounts, right-click the accounts, and select Move. When the Move dialog box appears, select the Active Directory container where you want the accounts moved and click OK.
In addition to working with the properties sheet for each computer account, you have several administrative tasks available to you when you right-click a computer account, including the following:
- Name Mappings—This option maps X.509 security certificates and Kerberos names for the computer account.
- Disable Account—This option prevents any users from logging on to the domain from the computer account. After you select this option, it toggles to read Enable Account, which you can later use for re-enabling the computer account.
- Reset Account—This option changes the computer account password that is used to authenticate the computer on the domain. If you reset a computer account, you must rejoin the computer to the domain.
- Move—This option allows you to relocate the computer account to a different container or OU.
- Manage—This option launches the Computer Management console for remotely administering the selected computer.
- All Tasks, Resultant Set of Policy (Planning)—This option lets you view simulated policy settings for a selected computer or a selected user.
- All Tasks, Resultant Set of Policy (Logging)—This option lets you view policy settings for a specific computer on the network.