Network | Dhcp

The Dynamic Host Provisioning Protocol (PROTOCOL, DHCP) is a local area network protocol that uses the UDP protocol to work with two main uses:

• Automatically assign an IP address to a user to an internal network or network service provider
• To the internal network administrator as a means of central management of all computers

DHCP uses the concept of a lease, or the validity period of a computer's IP address. The lease time is variable, depending on how long it takes for users to connect to the Internet somewhere, which is useful for environments where the education industry and other users frequently change. With a shorter lease, DHCP can dynamically reconfigure the network in an environment where more than one IP address is available to a computer. DHCP supports assigning a static address to a computer, such as a Web server that requires a permanent IP address.

When a computer or other networked device connects to a network, its DHCP client software in the operating system send s a broadcast query requesting necessary information. Any DHCP server on the network may service the request. The DHCP server manages a pool of IP addresses and information about client configuration parameters such as Defa Ult Gateway, domain name, the name servers, and time servers. On receiving a request, the server could respond with specific information for each client, as previously configured by an A Dministrator, or with a specific address and any other information valid for the entire network, and the time period for W Hich the allocation (lease) is valid.

The client broadcasts messages on the network subnet using the destination addres s 255.255.255.255 or the specific subnet

When a DHCP server receives a DHCPDISCOVER message from a client, which are an IP address lease request, the server

In response to the DHCP offer, the client replies with a DHCP request, broadcast to the server, requesting the offered address. A client can receive DHCP offers from multiple servers, But It would accept only one D HCP offer . Based on required server identification option in the request and broadcast messaging,

When the DHCP server receives the DHCPREQUEST message from the client, the configuration process is enters its final phase. The acknowledgement phase involves sending a DHCPACK packet to the client. This packet includes the lease duration and any other configuration information that the client might has reques Ted. The IP configuration process is completed.

After the client obtains a IP address, the client may use the address Resolution Protocol (ARP) to prevent address co Nflicts caused by overlapping address pools of DHCP servers.