1. Module 2: Allocating IP Addressing by Using Dynamic Host Configuration Protocol (DHCP)

2. Overview Multimedia: The Role of DHCP in the Network Infrastructure
Adding and Authorizing a DHCP Server Service
Configuring a DHCP Scope
Configuring a DHCP Reservation
Configuring DHCP Options
Configuring a DHCP Relay Agent

3. Multimedia: The Role of DHCP in the Network Infrastructure
The objective of this media is to provide a high-level overview of DHCP in the network infrastructure
At the end of this presentation, you will be able to:
Explain what DHCP is
Describe how DHCP works
Explain how routers can forward DHCP broadcast packets
Describe how a DHCP relay agent works

4. 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 Works
How to Add a DHCP Server Service
How a DHCP Server Service Is Authorized
How to Authorize a DHCP Server Service

5. Manual TCP/IP Configuration Automatic TCP/IP Configuration
Why Use DHCP?
DHCP reduces the complexity and amount of administrative work by using automatic TCP/IP configuration
Manual TCP/IP Configuration
IP addresses are entered manually on each client computer
Possibility of entering incorrect or invalid IP address
Incorrect configuration can lead to communication and network issues
Administrative overload on networks where computers are frequently moved
Automatic TCP/IP Configuration
IP addresses are supplied automatically to client computers
Ensures that clients always use correct configuration information
Client configuration is updated automatically to reflect changes in network structure
Eliminates a common source of network problems

6. How DHCP Allocates IP Addresses
DHCP Server
DHCP
Database
IP Address1: Leased to DHCP Client1
IP Address2: Leased to DHCP Client2
IP Address3: Available to be leased
DHCP Client2: IP configuration from DHCP server
Non-DHCP Client: Static IP configuration
DHCP Client1: IP configuration from DHCP server
Lease Renewal
Lease Generation

7. How the DHCP Lease Generation Process Works
DHCP Server2
DHCP Server1
DHCP Client
Graphic Artist:
After the third and fourth click, there seems to be a shadow returning of the objects that have exited. It may cause confusion for the learner.
You can straighten up with start and end points of the packets.
Or, you can try using the pulsing circles (instead of the packets) that represent broadcasts. You can find the pulsing circles graphic in Elise’s media piece titled, The Role of DHCP. The link to this media piece will be sent in an to you.
Also, for printing purposes, could you please set the slide build to print the last frame with all four bullets?
DHCP client broadcasts a DHCPDISCOVER packet 1
DHCP servers broadcast a DHCPOFFER packet 2
DHCP client broadcasts a DHCPREQUEST packet 3
DHCP Server1 broadcasts a DHCPACK packet 4

8. How the DHCP Lease Renewal Process Works
DHCP Client
DHCP Server1
DHCP Server2
DHCP client sends a DHCPREQUEST packet 1
DHCP Server1 sends a DHCPACK packet 2
50% of lease duration has expired
DHCP Client
DHCP Server1
DHCP Server2
100% of lease duration has expired
87.5% of lease duration has expired
50% of lease duration has expired
Graphic Artist:
Please clean up slide build.
There also seems to be some shadows of objects lingering after they have exited.
These aren’t broadcasts, so we need to use the packets in this slide build.
Also, for printing purposes, could you please set the slide build to print the frame that has the two bullets showing?
If the client fails to renew it’s lease, after 87.5% of the lease has expired, then the DHCP lease generation process starts over again with a DHCP client broadcasting a DHCPDISCOVER
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
DHCP Client sends a DHCPREQUEST packet 1
DHCP Server1 sends a DHCPACK packet 2

9. How to Add a DHCP Server Service
Your instructor will demonstrate how to:
Prepare to add a DHCP Server service
Add a DHCP Server service

10. How a DHCP Server Service Is Authorized
DHCP client receives IP address
from authorized DHCP Server1
Domain
Controller
Active
Directory
DHCP Client
Unauthorized
Does not service DHCP requests
Authorized
Services DHCP requests
DHCP Server1
DHCP Server2
DHCP Server1 checks with the domain controller to obtain a list of authorized DHCP servers
If DHCP Server1 finds its IP address on the list, the service starts and supports DHCP clients
Domain
Controller
Active
Directory
DHCP Client
DHCP Server1
Authorized
Services DHCP requests
DHCP Server2
Unauthorized
Does not service DHCP requests
Graphic Artist: For printing purposes, could you please set the slide build to print the last frame?
DHCP client receives IP address
from authorized DHCP Server1
DHCP Server2 checks with the
domain controller to obtain a list of
authorized DHCP servers
If DHCP Server2 does not find its IP address on the list, the service does not start and support DHCP clients
DHCP authorization is the process of registering the DHCP Server service in the Active Directory domain to support DHCP clients

11. How to Authorize a DHCP Server Service
Your instructor will demonstrate how to:
Apply the requirement for authorizing a DHCP Server service
Authorize a DHCP Server service

12. Practice: Adding and Authorizing a DHCP Server Service
In this practice, you will add and authorize a DHCP Server service

13. Lesson: Configuring a DHCP Scope
What Are DHCP Scopes?
How to Configure a DHCP Scope

14. A scope is a range of IP addresses that are available to be leased
What Are DHCP Scopes?
A scope is a range of IP addresses that are available to be leased
DHCP Server
LAN A
LAN B
Scope A
Scope B
Scope Properties
Network ID
Lease duration
Scope name
Subnet mask
Router
Exclusion range
Network IP address range

15. How to Configure a DHCP Scope
Your instructor will demonstrate how to:
Configure a DHCP scope
Activate a DHCP scope

16. Practice: Configuring a DHCP Scope
In this practice, you will configure a DHCP scope

17. Lesson: Configuring a DHCP Reservation
What Is a DHCP Reservation?
How to Configure a DHCP Reservation

18. What Is a DHCP Reservation?
A reservation is a specific IP address, within a scope, that is permanently reserved for leased use to a specific DHCP client
Subnet A
Subnet B
Workstation 1
DHCP Server
Workstation 2
File and Print Server
IP Address1: Leased to Workstation 1
IP Address2: Leased to Workstation 2
IP Address3: Reserved for File and Print Server

19. How to Configure a DHCP Reservation
Your instructor will demonstrate how to:
Configure a DHCP reservation
Verify a DHCP reservation

20. Practice: Configuring a DHCP Reservation
In this practice, you will configure a DHCP reservation

21. Lesson: Configuring DHCP Options
What Are DHCP Options?
How DHCP Server, Scope, and Reserved Client Options Are Applied
How DHCP Class-level Options Are Applied
How to Configure DHCP Options

22. DHCP Client IP Configuration Data
What Are DHCP Options?
DHCP options are configuration parameters that a DHCP service assigns to clients along with the IP address and default gateway
DHCP Client
DHCP Server
DHCP Client IP Configuration Data
Client’s IP address
Client’s subnet mask
DHCP options such as:
Router’s IP address
DNS server’s IP address
WINS server’s IP address
DNS domain name

23. How DHCP Server, Scope, and Reserved Client Options Are Applied
Scope B
Windows XP
DHCP Server
Windows 98
Router
File and Print Server
Scope A
Scope B
Windows XP
DHCP Server
Windows 98
Router
File and Print Server
Graphic Artist:
For printing purposes, could you please set the slide build to print the first frame?
DHCP option applied at the
reserved-client level
DHCP option applied at the
server level
DHCP option applied at the
scope level

24. How DHCP Class-level Options Are Applied
DHCP Server
File and Print Server
Windows 98
Scope A
Scope B
Router
Router
Windows XP
Windows XP
DHCP option applied at the
class level

25. How to Configure DHCP Options
Your instructor will demonstrate how to:
Configure a DHCP server option
Configure a DHCP scope option

26. Practice: Configuring DHCP Options
In this practice, you will configure DHCP options

27. 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 Threshold
How to Configure a DHCP Relay Agent

28. What Is a DHCP Relay Agent?
A DHCP relay agent is a computer or router configured to listen for DHCP/BOOTP broadcasts from DHCP clients and then relay those messages to DCHP servers on different subnets
DHCP Relay Agent
DHCP Server
Unicast
Broadcast
Broadcast
Subnet A
Subnet B
Graphic Artist:
You can try using the pulsing circles (instead of the arrows labeled “broadcast”) that represent broadcasts. You can find the pulsing circles in Elise’s media piece titled, The Role of DHCP. The link to this media piece will be sent in an to you.
Routers
Non-RFC 1542 Compliant
Client
Client
Client
Client

29. How a DHCP Relay Agent Works
Router
Non-RFC 1542 Compliant
Client1
DHCP Relay Agent
Client2
DHCP Server
Client3
DHCP Relay Agent
DHCP Server
Client2
Router
Non-RFC 1542 Compliant
Client3
Client1
Client1 broadcasts a DHCPDISCOVER packet 1
Relay agent forwards the DHCPDISCOVER message to the DHCP server 2
Server sends a DHCPOFFER message to the DHCP relay agent 3
Graphic Artist:
You can try using the pulsing circles (instead of the two simultaneous arrows that go from the client 1 to client 2 and DHCP Relay Agent) that represent broadcasts. You can find the pulsing circles in Elise’s media piece titled, The Role of DHCP. The link to this media piece will be sent in an to you.
Also, for printing purposes, could you please set the slide build to print the frame with all eight bullets, but no arrows?
Relay agent broadcasts the DHCPOFFER packet 4
Client1 broadcasts a DHCPREQUEST packet 5
Relay agent forwards the DHCPREQUEST message to the DHCP server 6
Server sends a DHCPACK message to the DHCP relay agent 7
Relay agent broadcasts the DHCPACK packet 8

30. How a DHCP Relay Agent Uses Hop Count
The hop count threshold is the number of routers that the packet can be transmitted through before being discarded
DHCP Relay Agent 2
Hop Count = 2
DHCP Relay Agent 1
Graphic Artist:
For printing purposes, could you please set the slide build to print the last frame?
DHCP Server

31. How a DHCP Relay Agent Uses Boot Threshold
The boot threshold is the length of time in seconds that the DHCP Relay Agent will wait for a local DHCP server to respond to client requests before forwarding the request
DHCP Server 2
DHCP Server 3
DHCP Relay Agent
Boot Threshold
= 10 seconds
Local DHCP Server
DHCP Server 2
DHCP Server 3
DHCP Relay Agent
Boot Threshold
= 10 seconds
Local DHCP Server
Graphic Artist:
For printing purposes, could you please set the slide build to print the last frame?

32. How to Configure a DHCP Relay Agent
Your instructor will demonstrate how to:
Apply guidelines for setting the hop count and boot threshold
Add a DHCP Relay Agent
Configure a DHCP Relay Agent with the IP address of the DHCP server
Enable the DHCP Relay Agent on a router interface

33. Practice: Configuring the DHCP Relay Agent
In this practice, you will configure a DHCP Relay Agent

34. Lab A: Identifying and Resolving Common Issues When Allocating IP Addressing by Using DHCP
In this lab, you will identify and resolve common issues when allocating IP addressing by using DHCP