DHCP Scope is a range of IP addresses that a DHCP server can lease out to DHCP clients.
What is DHCP Scope?
A range of IP addresses that a DHCP server can lease out to DHCP clients. You configure the DHCP scope using the Microsoft Windows NT administrative tool DHCP Manager or the Windows 2000 snap-in DHCP console. The IP addresses are leased for a specific Time to Live (TTL), usually three days. Information about scopes and leased IP addresses is stored in the DHCP database on the DHCP server.
The values for IP address scopes created on DHCP servers must be taken from the available pool of IP addresses allocated to the network.

Errors in configuring the DHCP scope are a common reason for problems in establishing communication on TCP/IP networks.
Non-DHCP clients
If non-DHCP clients have static IP addresses that fall within the range of the server’s DHCP scope, these static IP addresses must be excluded from the scope.
Otherwise, two hosts might end up with the same IP address, one assigned statically and the other assigned dynamically, resulting in neither host being able to communicate on the network.