Dhcp Services; Overview - D-Link NetDefendOS User Manual

Chapter 5: DHCP Services
This chapter describes DHCP services in NetDefendOS.
• Overview, page 393
• IPv4 DHCP Client, page 395
• IPv4 DHCP Server, page 397
• IPv4 DHCP Relay, page 404
• IP Pools, page 408
• DHCPv6, page 411

5.1. Overview

Dynamic Host Configuration Protocol (DHCP) is a protocol that allows network administrators to
automatically assign IP numbers to computers on a network. It can perform this function both for
IPv4 and IPv6 addresses.
IP Address Assignment
A DHCP Server implements the task of assigning IP addresses to DHCP clients. These addresses
come from a predefined IP address pool which DHCP manages. 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.
DHCP Leases
Compared to static assignment, where the client owns the address, dynamic addressing by a
DHCP server leases the address to each client for a predefined period of time. During the lifetime
of a lease, the client has permission to keep the assigned address and is guaranteed to have no
address collision with other clients.
Lease Expiration
Before the expiration of the lease, the client needs to renew the lease from the server so it can
keep using the assigned IP address. The client may also decide at any time that it no longer
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