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DHCP eases network configuration

The Dynamic Host Configuration Protocol (DHCP) was established to relieve the administrative burden of assigning and maintaining IP address information for internetwork connections. DHCP provides automatic and reliable TCP/IP network configuration, insures that address conflicts do not occur, and supports centralized management of address allocation.

When a client computer needs to start up TCP/IP operations, it broadcasts a request for address information. The DHCP Server assigns a new address and sends this to the client together with the lease duration, address of the client’s gateway and the subnet mask for the network that the client is on. This information is acknowledged by the client, and used to set up its network configuration. It eliminates much of the work required to set up clients manually and reduces the number of user errors caused by unfamiliarity with networking parameters. To guarantee non-duplication of IP addresses, each time a server issues an IP address it writes this information to non-volatile memory.

The network administrator controls which IP addresses are assigned, the maximum duration of leases, and all configuration parameters that are available to clients through DHCP. Most Windows clients renew their leases midway through the lease duration. An IP address is available for reallocation once its lease has expired without renewal. A client moving from one subnet to another must request a new IP address on the new subnet. This allows people with portable computers to move between subnets and remain connected to the network without the need for manual configuration. To identify who is using the network, the network administrator cross-checks the mandatory Ethernet address registration against the dynamic IP address currently assigned to that address.

Network Operations maintains a campus-wide DHCP service.  Many departments depend on this service to manage the assignment of IP addresses to computers in labs, classrooms and offices. DHCP is also used to assign IP addresses to laptops using the AirYork wireless service.