Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2
Some network devices need to use statically assigned IP addresses rather than addresses dynamically assigned through DHCP. For example, DHCP servers must have statically configured IP addresses. Also, some devices (such as legacy network printers) do not support DHCP.
For the devices that need static IP assignments, the company creates an exclusion range from each IP address range. Creating one or more exclusion ranges prevents the DHCP server from assigning a client lease with any address in the exclusion range, thereby protecting it for use as a static IP address and preventing address conflicts between statically configured devices and dynamically configured devices.
Although any addresses in the address range can be excluded, the company chooses to exclude the first 20 addresses from each address range for non-wireless subnets, and the first five IP addresses from each address range for wireless subnets. The company uses additional exclusion ranges to configure load balancing and fault tolerance using the 80/20 rule. For more information about DHCP scopes, see "Scope Configuration" later in this chapter.