Dhcp Services; Overview - D-Link NetDefend DFL-210 User Manual

Chapter 5. DHCP Services
This chapter describes DHCP services in NetDefendOS.
• Overview, page 96
• DHCP Servers, page 97
• Static DHCP Assignment, page 99
• DHCP Relaying, page 100

5.1. Overview

DHCP (Dynamic Host Configuration Protocol) is a protocol that allows network administrators to
automatically assign IP numbers to computers on a network.
A DHCP Server implements the task of assigning and managing IP addresses from a pre-defined ad-
dress pool to DHCP clients. When a DHCP server receives a request from a DHCP client, it returns
the configuration parameters (such as an IP address, a MAC address, a domain name, and a lease for
the IP address) to the client in a unicast message.
Compared to static assignment, where the client owns the address, dynamic addressing by a DHCP
server leases the address to each client for a pre-defined period of time. During the life cycle of the
lease, the client has permission to keep the assigned address and is guaranteed to have no address
collision with other clients. Before the expiration of the lease, the client needs to renew the lease
from the server, so it can keep using its IP address. The client may also decide at any time that it no
longer wishes to use the IP address it was assigned, and may terminate the lease by releasing the IP
address. The lease time can be configured in the DHCP server by the administrator.
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