How to install and configure the DHCP service for iSCSI Network Boot configuration in Windows Server 2003

This article discusses how to install and configure the Dynamic Host Configuration Protocol (DHCP) service for iSCSI Network Boot configuration in Microsoft Windows Server 2003.

To start separate computers to individually assigned iSCSI targets, you can use DHCP reservations. A reservation lets you specify the target, or "root path," and host name options for each computer. When you specify these options at the scope level or at the server level, all clients use the same root path and host name when the clients receive leases from the scope or from the server. The current iSCSI implementation does not support single image instancing. Therefore, you cannot use scope and server options to specify the root path.

Before you configure the DHCP service, make sure that you are not trying to host DHCP on a network that already has an active DHCP server. If you do this, you may disrupt service for users of the existing server.

How to install and configure the DHCP service for iSCSI startup

1. Install the DHCP service on a computer on the local network where the iSCSI client computer will be starting. To do this, follow these steps:
   1. Click Start, point to Control Panel, and then click Add or Remove Programs.
   2. In the Add or Remove Programs dialog box, click Add/Remove Windows Components.
   3. In the Windows Components Wizard, click Networking Services in the Components list, and then click Details.
   4. In the Networking Services dialog box, click to select the Dynamic Host Configuration Protocol (DHCP) check box, and then click OK.
   5. In the Windows Components Wizard, click Next to start the Setup program. Insert the Windows Server 2003 CD into the computer's CD drive or DVD drive if you are prompted to do this. Setup copies the DHCP server and tool files to the computer.
   6. When the Setup program is finished, click Finish.
2. If the DHCP server is not a domain member, go to step 3. Otherwise, authorize the DHCP server. In Windows Server 2003, DHCP servers in an Active Directory directory service-based domain must be authorized to prevent rogue DHCP servers from coming online. Any DHCP server that is running Windows Server 2003 and that is unauthorized cannot manage clients. To authorize the DHCP server, follow these steps:
   1. Click Start, point to Programs, point to Administrative Tools, and then click DHCP.
   2. In the console tree, click the server name, and then click Authorize on the Action menu.
   Notes
   • To authorize the server, you must be an enterprise administrator of the forest and a domain administrator for the server�s domain. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
     315370 Access is denied when you try to authorize a DHCP server in a child domain
   • A red down arrow may seem to indicate that the server is not authorized. However, the server status may not update immediately. Wait at least 30 seconds for the DHCP server to update the Active Directory, and then press F5 to update Microsoft Management Console (MMC). For more information, click the following article number to view the article in the Microsoft Knowledge Base:
     244638 Microsoft Management Console does not recognize new DHCP server
   • For more information about problems that may occur when you authorize the DHCP server, click the following article number to view the article in the Microsoft Knowledge Base:
     303317 You are unable to authorize DHCP Server in Active Directory
3. After you have installed and started the DHCP service, you must create a scope. A scope is a range of valid IP addresses that are available for lease to the DHCP client computers on the network. We recommend that each DHCP server in the environment have at least one scope that does not overlap with any other DHCP server scope in the environment. To create a scope, follow these steps:
   1. Click Start, point to Programs, point to Administrative Tools, and then click DHCP.
   2. In the console tree, right-click the DHCP server on which you want to create the new DHCP scope, and then click New Scope.
   3. In the New Scope Wizard, click Next, and then type a name and a description for the scope. The name may be any name that you want. However, the name should be descriptive enough so that you can determine the purpose of the scope on the network. For example, you may use a name such as "Administration Building Client Addresses."
   4. Click Next, and then type the range of addresses that can be leased as part of this scope. For example, use a range of IP addresses from a starting IP address of 192.168.100.1 through an ending address of 192.168.100.100. Because these addresses are given to clients, they must all be valid addresses for the network and currently not being used. If you want to use a different subnet mask, type the new subnet mask.
   5. Click Next, and then type any IP addresses that you want to exclude from the range that you entered. This includes any addresses in the range that have already been statically assigned to various computers in the organization. Domain controllers, Web servers, DHCP servers, Domain Name System (DNS) servers, and other servers typically have statically assigned IP addresses. Additionally, you must exclude the address that you will use to create a reservation in step 4c.
   6. Click Next, and then type the number of days, hours, and minutes before an IP address lease from this scope expires. This number determines how long a client may hold a leased address without renewing it.
   7. Click Next, and then click Yes, I want to configure these options now to extend the wizard to include settings for the most common DHCP options.
   8. Click Next, and then type the IP address for the default gateway that should be used by clients that obtain an IP address from this scope.
   9. Click Add to add the default gateway address in the list, and then click Next.
   10. If you are using DNS servers on this network, type the organization's domain name in the Parent domain box, type the name of the DNS server, and then click Resolve to make sure that the DHCP server can contact the DNS server and determine its address. Click Add to include that server in the list of DNS servers that are assigned to the DHCP clients, and then click Next. If you are using a Windows Internet Naming Service (WINS) server, follow these same steps to add its name and IP address, and then click Next.
   11. To activate the scope and to let clients obtain leases from the scope, click Yes, I want to activate this scope now, and then click Next.
   12. Click Finish.
4. Create a reservation. To do this, follow these steps:
   1. In the DHCP snap-in, expand the newly created scope for which you want to create a reservation.
   2. Select and then right-click Reservations, and then click New Reservation.
   3. In the New Reservation dialog box, enter values for Reservation name, for IP address, for MAC address, and for Description.
   4. Select the appropriate entries in Supported types. These should be set to BOOTP only or to Both.
5. Configure the reservation. To do this, follow these steps:
   1. Right-click the reservation that you just created, and then click Configure Options.
   2. Select the 012 - host name option, and then type the host name for the client.
   3. Select the 017 - root file option, and then type the iSCSI target's iSCSI Qualified Name (IQN).
   Note Each iSCSI initiator and target must have a worldwide unique name. Typically, this is an IQN name. The single IQN name applies to all iSCSI host bus adapters (HBAs) and to the Microsoft iSCSI Software Initiator in the system. You should configure an iSCSI HBA to have a different IQN name than the IQN name that is used by other iSCSI HBAs and by the Microsoft iSCSI Software Initiator. The Microsoft iSCSI Initiator service will automatically select an IQN name that is based on the Windows computer name, the domain name, and the Microsoft.com domain name address. If the Windows computer name or the domain name is changed, the IQN name also changes. However, an administrator can specifically configure the IQN name to be a fixed name instead of a generated name. If an administrator does this, the fixed name must be maintained as a worldwide unique name.

If you configure the iSCSI client computer and the DHCP server so that the iSCSI client computer receives a reserved IP address from the DHCP service, it will appear as if you had configured the iSCSI client computer to receive a static IP address from the DCHP service.

Note The DHCP server is running Windows Server 2003.

The server is now configured to provide an address and the appropriate options to this client. Some implementations might require you configure option 60 (ClassID) and sets the string value of PXEClient. This setting is configured as a server option and is displayed together with each reservation. If this option is missing after installation, install the option manually.

To configure additional clients, repeat steps 4 through 5 for each client. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
For more information about DHCP, visit the following Microsoft Web page:
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