Authorizing the Server

DHCP servers must be authorized if they are to be integrated in Active Directory networks. Only domain controllers and domain member servers participate in Active Directory, and only these server types can become authorized. When your network includes Active Directory domains, the first DHCP server you install on the network must be an authorized DHCP server.

Stand-alone or workgroup DHCP servers running Microsoft Windows 2000 Server or Windows Server 2003 cannot become authorized in Active Directory networks, but they can coexist with these networks as long as they are not deployed on a subnet with any authorized DHCP servers. (Note, however, that this configuration is not recommended.)

Stand-alone DHCP servers implemented together with authorized servers are known as rogue servers. When a rogue DHCP server running Windows Server 2003 or Windows 2000 Server detects an authorized server on the same subnet, the stand-alone server automatically stops its own DHCP Server service and stops leasing IP addresses to DHCP clients.

When the DHCP Server service is installed on a domain controller, you can perform the authorization procedure simply by right-clicking the server node in the DHCP console and selecting Authorize. You can use the following procedure, however, to authorize DHCP servers hosted on both domain controllers and member servers.

Caution Although you can install a DHCP server on a domain controller, this practice is not recommended for reasons discussed in the Security Concerns section in this tutorial.

Note To have the necessary permissions to authorize or deauthorize a DHCP server, you must be a member of the global security group Enterprise Admins.

To authorize a DHCP server in Active Directory, complete the following steps:

1. Open the DHCP console.
2. In the console tree, select DHCP.
3. From the Action menu, select Manage Authorized Servers.
   The Manage Authorized Servers dialog box opens.
4. Click Authorize.
5. When prompted, type the name or IP address of the DHCP server to be authorized, and then click OK.
6. When the Confirm Authorization dialog box appears, click OK again. Click Close in the Managed Authorized Servers dialog box to return to the DHCP console.