The Dynamic Host Configuration Protocol (DHCP) is a protocol that provides integrated management and dynamic configuration for clients.
DHCP adopts the client/server mode for communications. The client applies to the server for configurations such as the assigned IP address, subnet mask, and default gateway; the server replies with corresponding configurations according to policies.
With the rapid growth in network scales and increment of complexity, for example, the location of hosts frequently changes (for portable computers or wireless networks) and the number of hosts exceeds the number of assignable IP addresses, network configurations become more complicated. To properly and dynamically assign IP addresses to hosts, DHCP is applied.
DHCP is developed on the basis of the BOOTstrap Protocol (BOOTP). BOOTP runs in a static environment where each host has the fixed network connection. The administrator configures a specific BOOTP parameter file for each host and the file keeps unchanged within a long period. DHCP extends BOOTP in the following aspects:
DHCP can automatically assign the reusable network addresses and add configuration options.
DHCP enables a host to obtain an IP address dynamically rather than specifies an IP address for each host.
DHCP ensures reasonable allocation of IP addresses, which avoids wastes of IP addresses and improves the IP address usage of the whole network.
