DHCPScope

A DHCP scope is a defined range of IP addresses that a DHCP server can assign to clients on a given subnet. It is a fundamental concept in DHCP-based IP management, used to automate address assignment and reduce conflicts.

A scope is defined by a start IP and end IP, together with a subnet mask or prefix length. It may include exclusions (addresses that should not be assigned) and reservations (MAC-to-IP mappings for devices requiring fixed addresses). The scope also has a default lease duration, which sets how long a client can use an assigned address before it must renew.

DHCP options within the scope supply configuration to clients, such as the default gateway (router), DNS servers, domain name, time server, and other network parameters. These options can be global to the DHCP server or specific to a scope.

A server can host multiple scopes to administer several subnets or VLANs. Scopes help segment address management and prevent a server from leasing addresses outside a network segment. Exclusions and reservations allow administrators to reserve addresses or reserve addresses for particular devices while still being part of the pool.

In practice, the DHCP server offers available addresses from the active scope to clients; accepted leases are recorded in the DHCP database. Management involves monitoring lease activity, renewing leases, and updating options as network requirements change.