DYNAMIC HOST CONFIGURATON PROTOCOL

(DHCP)BY SIMSON JOSEPH

ROLL NO. 30

INTRODUCTIONThe DHCP is a network configuration protocol

for hosts on internet protocol networks.DHCP eliminates the manual task by a network.DHCP is used for IPV4 as well as IPV6.Alternatively,IPV4 hosts may use stateless

address autoconfiguration.IPV4 hosts may use link-local addressing to achieve limited local connectivity.

HISTORYDHCP was first defined as a standards track

protocol in RFC 1531 in October 1993,as an extension to the BOOTP.

Many worked to clarify the protocol as it gained popularity, and in 1997 RFC 2131 was released, and remains as of 2011 the standard for IPV4 networks.

DHCPv6 was further extended to provide configuration information to clients configured using stateless address autoconfiguration in RFC 3736.

What is RFC?Stands for request for commentsWhen standards are proposed ,they are

made available for public comment so that they can be refined and agreed upon.

The document which details the proposed standards is called a ”request for comments ” document.

TECHNICAL OVERVIEWDHCP automates network –parameter assignment

to network devices from one or more DHCP servers.The DHCP server manages a pool of IP address and

information about client configuration parameters such as default gateway , domain name , the name servers ,other servers such as time servers.

Depending on implementation , the DHCP server may have three methods of allocating IP-address.

METHODSDYNAMIC ALLOCATIONAUTOMATIC ALLOCATIONSTATIC ALLOCATION

DYNAMIC ALLOCATIONA network administrator assigns a range

of IP addresses to DHCP , and each client computer on the LAN is configured to request an IP address from the DHCP server during network initialization.

The request and grant process uses a lease concept with a controllable time period.

AUTOMATIC ALLOCATION

The DHCP server permanently assigns a free IP address to a requesting client from the range defined by the administrator.

MANUAL ALLOCATION

Server allocates an IP address based on a table with MAC address/IP address pairs , which are manually filled in by a network administrator.

The DHCP is used simply to convey the assigned address to the host.

RELIABILITYIt provides reliability in several ways :1.Periodic renewal2.Rebinding3.Failover

DISTINGUISHED BOOTP and DHCP

1.Design2.Capabilities3.Expiration4.Client support5.Phase6.Rebind or renew

SECURITYThe base DHCP protocol does not include

any mechanism for authentication.Because of this , it is vulnerable to a

variety of attacks.Unauthorized DHCP servers Unauthorized clientAttacks

CONCLUSIONDHCP is a network protocol that enables a

server to automatically assign an IP address to a computer from a defined range of numbers configured for a given network.

DHCP assigns an IP address when a system is started.

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