Automatic allocation(not Dynamic Allocation) on Windows DHCP server

DHCP supports three different mechanisms for IP address allocation:

Manual allocation: the server's administrator creates a configuration for the server that includes the MAC address and IP address of each DHCP client that will be able to get an address: functionally equivalent to BOOTP though the protocol is incompatible.

Automatic allocation: the server's administrator creates a configuration for the server that includes only IP addresses, which it gives out to clients. An IP address, once associated with a MAC address, is permanently associated with it until the server's administrator intervenes.

Dynamic allocation: like automatic allocation except that the server will track leases and give IP addresses whose lease has expired to other DHCP clients

How can i configure the automatic allocation on Windows 2000 or XP DHCP server?

i can think of setting the lease to unlimited period, but i m not sure if the computer shutsdown gracefully it will make the ip address available to other machine.

For Windows DHCP server:

Lease Duration: Required to specify the duration for which address assignments are good. If the Unlimited box is checked, then address assignments never expire; otherwise, specify the lease duration in number of days, hours, and minutes in the Limited To section.

This is as much support for Automatic DHCP allocation as you can get out of Windows DHCP server.

However, odd network problems can occur in an automatic DHCP network if you don't fully understand the consequences. Think carefully about the various scenarios that can occur (server down while client powers on, for instance). For this and other reasons, Automatic is rarely a good choice.