allocating ip addresses by using dhcp

8/8/2019 Allocating IP Addresses by Using DHCP

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Module 2: Allocating IPAddressing by Using Dynamic

Host Configuration Protocol(DHCP)


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Overview

Multimedia: The Role of DHCP in the NetworkInfrastructure

Adding and Authorizing a DHCP Server Service

Configuring a DHCP Scope

Configuring a DHCP Reservation

Configuring DHCP Options

Configuring a DHCP Relay Agent


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Lesson: Adding and Authorizing a DHCP Server Service

Why Use DHCP?

How DHCP Allocates IP Addresses

How the DHCP Lease Generation Process Works

How the DHCP Lease Renewal Process WorksHow to Add a DHCP Server Service

How a DHCP Server Service Is Authorized

How to Authorize a DHCP Server Service


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How the DHCP Lease Generation Process Works

DHCP client broadcasts a DHCPDISCOVER packet1DHCP servers broadcast a DHCPOFFER packet2

DHCP client broadcasts a DHCPREQUEST packet3

DHCP Server1 broadcasts a DHCPACK packet4

DHCP

Client

DHCP

Server1

DHCP

Server2


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How the DHCP Lease Renewal Process Works

DHCP ClientDHCP

Server1

DHCP

Server2

DHCP Client sends a DHCPREQUEST packet1

DHCP Server1 sends a DHCPACK packet2

50% of leaseduration has

expired

87.5% of leaseduration has

expired


expired

If the client fails to renew its lease, after 50% of the lease

duration has expired, then the DHCP lease renewal process will

begin again after 87.5% of the lease duration has expired

If the client fails to renew its lease, after 87.5% of the lease hasexpired, then the DHCP lease generation process starts overagain with a DHCP client broadcasting a DHCPDISCOVER

DHCP ClientDHCP

Server1

DHCP

Server2

DHCP client sends a DHCPREQUEST packet1

DHCP Server1 sends a DHCPACK packet2


expired


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How to Add a DHCP Server Service

Your instructor will demonstrate how to:

Prepare to add a DHCP Server service

Add a DHCP Server ser

vice


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How a DHCP Server Service Is Authorized

DomainController

Active

Directory

DHCP Client

DHCP Server1 checks with thedomain controller to obtain a list

of authorized DHCP servers

Unauthorized

Does not service

DHCP requests

Authorized

Services DHCP

requests

DHCP Server1

DHCP Server2

If DHCP Server1 finds its IPaddress on the list, the service

starts and supports DHCP clients

DHCP Server2 checks with thedomain controller to obtain a list ofauthorized DHCP servers

If DHCP Server2 does not find its IPaddress on the list, the service doesnot start and support DHCP clients

DHCP client receives IP addressfrom authorized DHCP Server1

DHCP client receives IP addressfrom authorized DHCP Server1

DomainController

Active

Directory

DHCP Client Unauthorized

Does not service

DHCP requests

Authorized

Services DHCP

requests

DHCP Server1

DHCP Server2

DHCP authorization is the process of registering the DHCP Server service in the

Active Directory domain to support DHCP clients


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How to Authorize a DHCP Server Service


Apply the requirement for authorizing a DHCP Serverservice

Authorize a DHCP Server service


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Lesson: Configuring a DHCP Scope

What Are DHCP Scopes?

How to Configure a DHCP Scope


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What Are DHCP Scopes?

A scope is a range of IP addresses that are available to be leased

Scope PropertiesNetwork ID Lease duration Scope name

Subnet mask Router Exclusion range

Network IPaddress range

LAN A LAN B

DHCP Server

Scope BScope A


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How to Configure a DHCP Scope


Configure a DHCP scope

Activate a DHCP scope


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Practice: Configuring a DHCP Scope

In this practice, you will configure a DHCPscope


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Lesson: Configuring a DHCP Reservation

What Is a DHCP Reservation?

How to Configure a DHCP Reservation


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What Is a DHCP Reservation?

A reservation is a specific IP address, within a scope, that ispermanently reserved for leased use to a specific DHCP client

Subnet A Subnet B

Workstation 1

DHCP Server

Workstation 2

File andPrint Server

IP Address1: Leased to Workstation 1

IP Address2: Leased to Workstation 2

IP Address3: Reserved forFile and Print Server


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Practice: Configuring a DHCP Reservation

In this practice, you will configure a DHCPreservation


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Lesson: Configuring DHCP Options

What Are DHCP Options?

How DHCP Server, Scope, and Reserved Client OptionsAre Applied

How DHCP Class-level Options Are Applied

How to Configure DHCP Options


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What Are DHCP Options?

DHCP options are configuration parameters that a DHCPservice assigns to clients along with the IP address anddefault gateway

DHCP Client

DHCP Server

DHCP Client IP Configuration Data

Clients IP address

Clients subnet mask

DHCP options such as:

Routers IP addressDNS servers IP addressWINS servers IP addressDNS domain name


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How DHCP Server, Scope, and Reserved Client OptionsAre Applied

DHCP option applied at the

server level


scope level


reserved-client level

Scope A Scope B

Windows XP

DHCP ServerWindows 98

Windows XP

Router


Scope A Scope B

Windows XP


Windows XP

Router



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How DHCP Class-level Options Are Applied


class level

Scope A Scope B


Windows XP Windows XP

Router Router



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How to Configure DHCP Options


Configure a DHCP server option

Configure a DHCP scope option


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Practice: Configuring DHCP Options

In this practice, you will configure DHCPoptions


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Lesson: Configuring a DHCP Relay Agent

What Is a DHCP Relay Agent?

How a DHCP Relay Agent Works

How a DHCP Relay Agent Uses Hop Count

How a DHCP Relay Agent Uses Boot ThresholdHow to Configure a DHCP Relay Agent


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What Is a DHCP Relay Agent?

A DHCP relay agent is a computer or router configured to listen forDHCP/BOOTP broadcasts from DHCP clients and then relay those messagesto DCHP servers on different subnets

DHCP Server

Client

DHCP Relay Agent

Client Client Client

Routers

Non-RFC 1542Compliant

UnicastUnicast

Broadcast

Subnet A Subnet B

Broadcast


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How a DHCP Relay Agent Uses Hop Count

The hop count threshold is the number of routers that the packet can betransmitted through before being discarded

DHCP Relay Agent 2

DHCP Server

Hop Count = 2

DHCP Relay Agent 1


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How a DHCP Relay Agent Uses Boot Threshold

DHCP Server 2

DHCP Server 3

DHCP Relay Agent

Boot Threshold

= 10 seconds

Local DHCPServer

DHCP Server 2

DHCP Server 3

DHCP Relay Agent

Boot Threshold

= 10 seconds

Local DHCPServer

The boot threshold is the length of time in seconds that the DHCPRelay Agent will wait for a local DHCP server to respond to clientrequests before forwarding the request


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Practice: Configuring the DHCP Relay Agent

In this practice, you will configure a DHCPRelay Agent


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Lab A: Identifying and Resolving Common Issues WhenAllocating IP Addressing by Using DHCP

In this lab, you will identify and resolvecommon issues when allocating IPaddressing by using DHCP

allocating ip addresses by using dhcp

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