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after yesterday talking about web servers and DNS servers, now I will discuss about the DHCP.

DHCP (Dynamic Host Configuration Protocol) is a protocol-based client / server architecture that is used to facilitate pengalokasianalamat IP within one network. A local network that does not use DHCP to give IP addresses to all computers manually. If DHCP is installed on the local network, then all the connected computers in the network will get an IP address automatically from a DHCP server. In addition to IP addresses, many network parameters that may be provided by DHCP, such as default gateway and DNS server.

How it Works
Because DHCP is a protocol that uses client / server architecture, then the DHCP there are two parties involved, namely DHCP Server and DHCP Client.
DHCP server is a machine that runs a service that can "lease" IP addresses and TCP / IP information to all other clients who request it. Some network operating systems like Windows NT Server, Windows 2000 Server, Windows Server 2003, or GNU / Linuxmemiliki service like this.

DHCP client is a client machine running the DHCP client software that allows them to be able to communicate with the DHCP Server. Most of the network client operating systems (Windows NT Workstation, Windows 2000 Professional, Windows XP, Windows Vista, atauGNU / Linux) have a software like this.
DHCP servers generally have a set of addresses that are allowed to distribute to clients, which called the DHCP Pool. Each client would then hire an IP address from the DHCP pool for the time specified by DHCP, usually up to several days. When the IP address lease time expires, the client will ask the server to provide new IP address or extend it.
DHCP Client will try to get the "leasing" an IP address from a DHCP server in the following four steps:

DHCPDISCOVER: DHCP client broadcasts a request to deploy to locate a DHCP server active.
DHCPOFFER: Upon hearing a broadcast from a DHCP Server DHCP Client, DHCP server then offers an address to the DHCP client.
DHCPREQUEST: DCHP Client asks server to lease IP address from one of the available addresses in the DHCP pool on the DHCP Server in question.
DHCPACK: DHCP server will respond to requests from clients by sending an acknowledgment packet. Then, the DHCP server will assign an address (and configuring TCP / IP) to the client, and update the data base his own database. The client will then begin the process of binding to the protocol stack TCP / IP and therefore already has an IP address, the client can initiate communication.
Four stages of the above applies only to clients who do not have addresses. For clients who had previously asked for the address to the DHCP server is the same, only stage 3 and stage 4 is carried out, namely the stage of the update address (address renewal), which is obviously much faster process.
Unlike the DNS system is distributed, a stand-alone DHCP, so if in a network there are several DHCP servers, database IP address in a DHCP Server DHCP will not be replicated to other servers. This can be a problem if the configuration between two DHCP servertersebut collide, because the IP protocol does not allow two hosts have the same address.
In addition to providing a dynamic address to a client, DHCP server also can assign a static address to a client, so the address of the client will still from time to time.
Note: The DHCP server must have a static IP address.

DHCP Scopes 
DHCP Scope is the IP addresses that can be leased to DHCP clients. It can also be configured by an administrator using the DHCP server configuration tools. Typically, an IP address leased within a specified period, referred to as DHCP Lease, which is generally worth three days. Information about DHCP Scopes and IP addresses that have been leased and then stored in the database DHCP in the DHCP server. The value of IP addresses that can be leased must be retrieved from the DHCP pool of available allocated in the network. Mistakes that often occur in the configuration of the DHCP Server is a mistake in the configuration of the DHCP Scope.

DHCP Lease
DHCP Lease is the IP address lease time limit granted to the DHCP client by the DHCP Server. Generally, this can be configured as such by an administrator by using some of the equipment configuration (in Windows NT Server can use DHCP Manager or the Windows 2000 upwards can use the Microsoft Management Console [MMC]). DHCP Lease is also often called sebagaiReservation.

DHCP Options
DHCP Options are additional settings for the IP address assigned by DHCP to DHCP clients. When a client asks for the IP address of the server, the server will provide at least an IP address and subnet address of the network. DHCP server can also be configured in such a way as to provide additional information to the client, which can certainly be done by an administrator. DHCP Options can be applied to all clients, DHCP Scope particular, or to a specific host within the network.