Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2
For clients that require a constant IP address, you can either manually configure a static IP address, or assign a reservation on the DHCP server. Reservations are permanent lease assignments that are used to ensure that a specified client on a subnet can always use the same IP address. You can use DHCP reservations for hosts that require a consistent IP address, but do not need to be statically configured. Reserved IP addresses differ from statically configured IP addresses in one significant manner: when network parameters are changed at the DHCP server, the device configured with a reserved IP address receives the new network parameters when the device requests renewal of its lease. To change network parameters on a device configured with a static IP address, the changes must be made manually to the device.
Determine the clients for which you need to manually configure an IP address — such as DHCP server, DNS servers, WINS servers, routers, and domain controllers — and which clients can receive addresses from DHCP. Keep in mind that for clients for which you manually configure static IP addresses, you must insert all configuration parameters that the client requires in order to interact with the network. This includes IP addresses, DNS and WINS parameters, and default gateway information. Clients that have reserved IP addresses always have the same IP address, but still receive updated configuration information from the DHCP server.
You might want to assign network printers and certain servers DHCP reservations to ensure that they always have the same IP address, but continue to receive updated configuration information from the DHCP server. For example, create reservations for servers that must always have the same IP address, such as:
- Windows Internet Name Service (WINS) and Domain Name System (DNS) servers
- Print servers that use TCP/IP print services
DHCP-enabled clients receive any available options, such as DNS server or router (default gateway), from the DHCP server when they renew their leases. If these devices are manually configured, an administrator must reconfigure each device individually when a change occurs.
To create a reservation
- In the DHCP snap-in, expand the scope for which you want to create a reservation.
- Select and right-click Reservations, and then click New Reservation.
- In the NewReservation dialog box, enter the Reservation name, IP address, MAC address, and Description of the reservation.
- Select the appropriate Supported types: DHCP only, BOOTP only, or Both.
- Click Add.