What is DHCP?Dynamic Host Configuration Protocol

What is DHCP principle

Dynamic Host Configuration Protocol (DHCP) is a network management protocol used to automate the procedure of configuring devices on IP networks, thus allowing them to use network services such as DNS, NTP, and any communication protocol based on UDP or TCP. A DHCP server dynamically assigns an IP address and other network configuration parameters to each device on a network so they can communicate with other IP networks. DHCP is an enhancement of an older protocol called BOOTP. DHCP is an important part of the DDI solution (DNS-DHCP-IPAM).

Watch & Learn from Suzanne: DHCP fundamentals in 20 minutes

This video is an abstruse of our DHCP demystified preparation available in our DDI introduction cursus composed of DHCP, DNS and IPAM. By watching it, yous will learn the role of DHCP, the principles of the DHCP protocol and the message flows between a client and a server.

Configuration Data Sent by DHCP Server and Key Values

The basic flow is that a DHCP server easily out configuration information, based on the ambassador'due south policy, to a requesting client. Common network parameters (sometimes referred to as "DHCP Options") requested include subnet mask, router, domain name server, hostname and domain proper noun.

Equally the requesting client has no IP accost when joining the network, it broadcasts the request. The protocol is thus used in a very early phase of IP communication. If such dynamic protocol is not used to get an IP address, the client has to employ a predefined IP address mostly called "static IP address", which is manually configured on the customer network interface in configuration files or with a specific command.

The DHCP service brings three primal values: 1) Performance tasks are reduced: the network administrator no longer needs to manually configure each customer before it tin use the network 2) The IP addressing plan is optimized: addresses no longer beingness used are freed up and made available to new clients connecting 3) User mobility is hands managed: the ambassador doesn't need to manually reconfigure a customer when its network access point changes.

What is DHCP-DHCP lease

DHCP Lease Time Management

The IP address information assigned past DHCP is only valid for a limited catamenia of time, and is known as a DHCP lease. The menstruation of validity is called the DHCP charter time. When the lease expires, the client can no longer use the IP address and has to stop all advice with the IP network unless he requests to extend the lease "rent" via the DHCP lease renewal bicycle. To avoid impacts of the DHCP server not being available at the end of the lease time, clients by and large showtime renewing their charter halfway through the charter period. This renewal process ensures robust IP address resource allotment to devices. Any device request for a new IP version 4 accost at arrival on the network and not receiving an answer volition use automatic private internet protocol addressing (APIPA) to select an address. These addresses are in the network range 169.254.0.0/16.

Usage Scenarios

There are four key DHCP usage scenarios: ane. Initial Client Connection: the client requests from the DHCP server an IP address and other parameter values for accessing network services 2. IP Usage Extension: the client contacts the DHCP server to extend usage of its current IP address three. Client Connection Later on Reboot: the customer contacts the DHCP server for confirmation that it can apply the same IP address being used before reboot 4. Customer Disconnection: the customer requests the DHCP server to release its IP address.

What is DHCP-DHCP options

DHCP Options

DHCP options can be used to automatically provide clients with data on the network services it tin utilise. This is a very efficient way to button the IP address of the time server, the mail server, the DNS server and the printer server. This can as well be used to provide a file name and a file server that volition exist used past the client to start a specific kick process – mainly used for IP phones and Wi-Fi access points, only can too be used for auto-installing clients and servers with PXE (Preboot eXecution Environment).

Implementation of DHCP Service

The original and well-nigh comprehensive implementation of the DHCP service is offered by the Internet Systems Consortium (ISC). Supporting both IPv4 and IPv6, ISC DHCP offers a consummate open source solution for implementing DHCP servers, relay agents, and clients. Other DHCP Server products include the Microsoft DHCP server.

The DHCP service can exist enhanced by DHCP failover to bring high availability and load balancing of traffic. The ISC DHCP Failover relies on having a pair of collaborating servers – a primary (main) server and a secondary (backup) server. A TCP-based communication channel, called a failover aqueduct, then has to exist set up between the two servers.

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Smart DDI Solution

Network complexity increases administrator tasks and causes configuration errors. With an integrated DDI solution you can simplify, automate and secure your network.

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DHCP is a simple simply vital service for management of large networks. It ensures devices can connect to networks for accessing critical business services.