DHCPS : DHCP Server
DHCP is a protocol used by networked computers (clients) to obtain unique IP addresses, and other parameters such as default router, subnet mask, and IP addresses for DNS servers from a DHCP server. This protocol is used when computers are added to a network because these settings are necessary for the host to participate in the network. This setting is periodically refreshed (it expires, meaning the client must obtain another assignment) with typical intervals ranging from one hour to several months, and can, if desired, be set to infinite (never expire). The length of time the address is available to the device it was assigned to is called a lease, and is determined by the server. The DHCP server ensures that all IP addresses are unique, that is, no IP address is assigned to a second client while the first client's assignment is valid (its lease has not expired). Thus IP address pool management is done by the server and not by a human network administrator. DHCP emerged as a standard protocol in October 1993. As of 2006, RFC 2131 provides the latest ([dated March 1997]) DHCP definition. DHCP functionally became a successor to the older BOOTP protocol, whose leases were given for infinite time and did not support options. Due to the backward-compatibility of DHCP, very few networks continue to use pure BOOTP.