Configuring DHCP Reservations in SBS 2003

While the default SBS install creates a stable DHCP server configuration (when DHCP is enabled on the SBS server, and it should be), sometimes there are reasons to have a network device receive a consistent IP address on the internal network. This could be a network-aware printer that needs a fixed IP or if you need to group a set of workstations in a specific IP address range for ISA. This post covers the steps to follow to create a DHCP reservation on an SBS 2003 server.

First, you will need to know the MAC address for the Ethernet interface on the network device. The process for getting this information varies with the type of device. Instructions for some common devices are listed below.

Windows 2000/XP workstations

Open a command prompt and run ipconfig /all. Look for the Physical Address in the output of the command.

Macintosh OS X

Open System Preferences from the Apple Menu and click on the Network icon. Double-click on the appropriate network interface (probably Built-in Ethernet) then click the Ethernet tab. The address is listed as the Ethernet ID.

Macintosh OS 9 and earlier

From the Apple Menu, select Control Panels, and then click TCP/IP. Click the Info button. The address is listed in the new window.

Now that you have the MAC address for the devices Ethernet interface, follow these steps to create the DHCP reservation on the SBS server.

1. Open the DHCP Management Console either from the Administrative Tools folder or by running dhcpmgmt.msc.

2. Expand the server name, Scope, and click on Reservations.
3. Right-click on the Reservations icon and select New Reservation.
4. Enter a name for the reservation (i.e., the device’s DNS name, if any).
5. Enter an IP address for the device.
6. Enter the MAC address for the device. The MAC address should contain no spaces or special characters. Enter only the 12-digit hexadecimal number for the address. Case does not matter.
7. Enter a description for the device if desired.
8. Leave Both selected under Supported Types unless you really want to select DHCP only.
9. Click Add, then click Close.

You will now see an icon for the device under the Reservation folder. If you click on the Address Leases folder, you will also see the device name and address listed, but under the Lease Expiration column, you will see Reservation (inactive).

At this point you can renew the DHCP lease on the device or reboot it so it will get its new address from the DHCP reservation. When the device has correctly pulled its address from the DHCP server, you will see Reservation (active) listed under the Lease Expiration column in the Address Leases view.

DHCP Reservation settings will be retained if the Connect to the Internet wizard (CEICW) is run again, but the reservation will be deleted if the Change Server IP Address Wizard is run.