Dynamic Host Configuration Protocol – DHCP.
Dynamic Host Configuration Protocol works in a client/server mode. DHCP enables clients on an IP network to obtain or lease IP address or configuration from a DHCP server. This reduces workload when managing a large network. DHCP protocol is described in the RFC 2131.
Most modern operating system includes DHCP in their primary settings, these includes windows OS, Novell NetWare, Sun Solaris, Linux and Mac OS. The clients’ requests for addressing configuration from a DHCP network server, the network server manages the assignment of IP addresses and must be obliged to answer to any IP configuration requests from clients.
However, network routers, switches and servers need to have a static IP addresses, DHCP is not intended for the configuration of these types of hosts. Cisco routers use a Cisco IOS features known as Cisco Easy IP Lease. This offers an optional but full-featured DHCP server. Easy IP leases address for 24hrs by default, it is most useful in homes and small offices where users can take the advantages of DHCP and NAT without having an NT or UNIX server
The DHCP sever uses User Datagram Protocol (UTP) as it’s transport protocol to send message to the client on port 68, while the client uses port 67 to send messages to the server.
DHCP severs can offer other information, this include, DNS server addresses, WINS server addresses and domain names. In most DHCP servers, administrators are allowed to define clients MAC addresses, which the server automatically assigns same IP, address each time.
Most administrators prefer to work with Network server that offers DHCP services. These types of network are scalable and easy to manage.
Dynamically Allocating Client IP Addresses via DHCP on Cisco router