IT 3110



Dynamic Host Configuration Protocol

What does it do?

DHCP components

Server - receives clients’ requests and replies to them. Client - bundled with the operating system of a client computer or other IP capable device and which sends configuration requests to the server. Relay agent - used in the case the dhcp request needs to travel to a different LAN (allows a single dhcp server to serve many LANS)

DHCP Procedure (DORA)

DHCP Details

DHCP Details

DHCP Lease renewal

DHCP Leases

Every time a client device restarts within the lease period, it contacts the configured default gateway. If the gateway does not respond, the client considers itself to be on a new subnet and enters the discovery phase.

Clients will redo DORA when they detect they are on a new network.


Types of Leases


DNS expects known ip addresses. DHCP can cause IP addresses to change. How to make sure DNS records are the ones that DHCP has served out? DNS dynamic update: dhcp will make modifications to your DNS entries.


DHCP is used with IPv6… but it works a little differently.

Our environment

Before we set up dhcp let’s consider what we might have.

Network: - Hosts: (all statically configured)

    ns1     IN      A
    ns2     IN      A
    www     IN      A
    db      IN      A
    dhcp    IN      A
    logger  IN      A
    client1 IN      A
    client2 IN      A

Goal (your assignment may be different)