The Dynamic Host Configuration Protocol (DHCP) dynamically assigns IP addresses to hosts and centrally manages host configurations. DHCP uses the client/server model. A client applies to the server for configuration parameters, such as an IP address, subnet mask, and default gateway address; the server replies with the requested configuration parameters.
A host can send packets to or receive packets from the Internet after it obtains an IP address, as well as the router address, subnet mask, and DNS address.
The Bootstrap Protocol (BOOTP) was originally designed for diskless workstations to discover their own IP addresses, the server address, the name of a file to be loaded into memory, and the gateway IP address. BOOTP applies to a static scenario in which all hosts are allocated permanent IP addresses.
However, as the increasing network scale and network complexity complicate network configuration, the proliferation of portable computers and wireless networks brings about host mobility, and the increasing number of hosts causes IP address exhaustion, BOOTP is no longer applicable. To allow hosts to rapidly go online or offline, as well as to improve IP address usage and support diskless workstations, an automatic address allocation mechanism is needed based on the original BOOTP architecture.
DHCP was developed to implement automatic address allocation. DHCP extends BOOTP in the following aspects:
DHCP rapidly and dynamically allocates IP addresses, which improves IP address usage and prevents the waste of IP addresses.