Active Directory Cookbook

18.12. Authorizing a Microsoft DHCP Server

Problem

You want to authorize a Microsoft DHCP server in Active Directory so that clients can use it.

Solution

Using a graphical user interface

1. Open the DHCP snap-in.

2. In the left pane, right-click on DHCP and select New Server.

3. Type in the name of the new DHCP server and click OK.

4. Click on the server entry in the left pane.

5. Right-click on the server and select Authorize.

Discussion

Windows 2000- and Windows Server 2003-based DHCP servers must be authorized before they can give out leases to clients. This feature helps reduce the occurrence of rogue DHCP servers that an end-user sets up, perhaps even unintentionally. A rogue DHCP server can provide incorrect lease information or deny lease requests altogether, ultimately causing a denial of service for clients on your network.

If the DHCP Server service is enabled on a domain controller, it is automatically authorized. A DHCP server that is a member server of an Active Directory domain performs a query in Active Directory to determine whether it is authorized. If it is, it will respond to DHCP requests, if not, it will not respond to requests. A standalone DHCP server that is not a member of an Active Directory domain sends out a DHCPINFORM message when it first initializes. If an authorized DHCP server responds to the message, the standalone server will not respond to any further DHCP requests. If it does not receive a response from any DHCP servers, it will respond to client requests and give out ...