1. IMPLEMENTING DHCP Chapter 1
Briefly discuss the topics covered in the chapter. Refer to the objectives list at the beginning of the chapter.

2. Chapter 1: IMPLEMENTING DHCP
HISTORY OF DHCP
Discuss the evolution of dynamic address assignment with Reverse Address Resolution Protocol (RARP), Bootstrap Protocol (BOOTP), and Dynamic Host Configuration Protocol (DHCP).

3. Chapter 1: IMPLEMENTING DHCP
THE ROLE OF DHCP
Dynamically assigns TCP/IP addresses
Dynamically assigns TCP/IP configuration information
Simplifies network administration
Explain that DHCP simplifies administration by providing a centrally managed database of all IP configuration information.

4. DYNAMIC VERSUS MANUAL TCP/IP ADDRESS ASSIGNMENT
Chapter 1: IMPLEMENTING DHCP
DYNAMIC VERSUS MANUAL TCP/IP ADDRESS ASSIGNMENT M a n u l T C P / I o f i g r t A m c
IP addresses entered manually
on each client computer
IP addresses are supplied auto-
matically to client computers
Possibility of entering incorrect
or invalid IP address
Ensures that client always uses
correct configuration information
Incorrect configuration can
lead to communication
and network issues
Client configuration updated
automatically to reflect network
changes
Administrative overload on
networks on which computers
are frequently moved
Elimination of source of network
problems
Discuss manual address assignment and explain the potential problems that can occur as your network grows.
Discuss dynamic address assignment and how DHCP has eliminated many of the potential problems of IP address assignment.
Mention that automatic address assignment is discussed later in the lecture about this chapter.

5. MANUAL TCP/IP ADDRESSING
Chapter 1: IMPLEMENTING DHCP
MANUAL TCP/IP ADDRESSING
Demonstrate how to open My Network Places and how to set local area network (LAN) adapter properties.
Explain that manual address assignment requires that an administrator manually configure the address setting for each client.
Explain how Domain Name System (DNS) settings that are manually configured will override dynamic settings that were obtained through DHCP.

6. DYNAMIC TCP/IP ADDRESS ASSIGNMENT
Chapter 1: IMPLEMENTING DHCP
DYNAMIC TCP/IP ADDRESS ASSIGNMENT
This slide illustrates the default setting for Microsoft Windows 2000, Microsoft Windows XP, and Microsoft Windows Server Point out that dynamic address assignment reduces administrative overhead and the potential for errors.

7. DHCP SERVER REQUIREMENTS
Chapter 1: IMPLEMENTING DHCP
DHCP SERVER REQUIREMENTS
DHCP server requirements
Microsoft Windows NT, Windows 2000, or Windows Server 2003 Server products
The DHCP Server service installed on the server
Static IP address, subnet mask, and default gateway
Valid range of addresses
Emphasize the reason why DHCP servers require static IP addresses. This becomes more important when you discuss DHCP relay agents later in the lecture about this chapter.

8. DHCP CLIENT REQUIREMENTS
Chapter 1: IMPLEMENTING DHCP
DHCP CLIENT REQUIREMENTS
DHCP client requirements
Windows XP or Windows 2000
Microsoft Windows NT 3.51 or later
Microsoft Windows 95 or Microsoft Windows 98
Microsoft Windows 3.11 for Workgroups with TCP/IP-32
Microsoft Network Client 3 for MS-DOS
LAN Manager 2.2c
Other non-Microsoft operating systems

9. Chapter 1: IMPLEMENTING DHCP
KEY BENEFITS OF DHCP
Centralized administration of IP configuration
Dynamic host configuration
Seamless IP host configuration
Flexibility
Scalability

10. HOW THE DHCP PROCESS WORKS
Chapter 1: IMPLEMENTING DHCP
HOW THE DHCP PROCESS WORKS
1. DHCP clients request addressing information from DHCP servers.
2. DHCP servers respond to DHCP client requests for addressing information by offering a lease.
3. DHCP leases contain the IP addressing information provided to the client.

11. Chapter 1: IMPLEMENTING DHCP
DHCP MESSAGE TYPES
Used by clients to obtain additional TCP/IP addresses D H C P M e s a g T y p c r i t o n
DHCPDISCOVER
Used by clients to request configuration parameters
from a DHCP server
DHCPOFFER
Used by servers to offer IP addresses to requesting
clients
DHCPREQUEST
Used by clients to accept or renew IP address
assignment and to decline unaccepted servers
DHCPDECLINE
Used by clients to reject an offered IP address
DHCPACK
Used by servers to acknowledge a client’s
acceptance of an offered IP address
DHCPNACK
Used by servers to reject a client’s acceptance of an
offered IP address
DHCPRELEASE
Used by clients to terminate an IP address lease
DHCPINFORM
Explain each type of message and give an example of when each is used. For example, explain messages that are used during the initial lease process, when attempting to renew a lease, when a lease request is declined, when a DHCP server declines a request for a lease renewal, and so on.
These message types also are discussed in the next two slides.

12. THE INITIAL DHCP LEASE PROCESS
Chapter 1: IMPLEMENTING DHCP
THE INITIAL DHCP LEASE PROCESS
This slide illustrates the use of four of the message types discussed in the previous slide.
Explain that DHCPDISCOVER messages are broadcast and that any DHCP server that receives the message can respond with a lease offer.

13. DHCP LEASE RENEWAL PROCESS
Chapter 1: IMPLEMENTING DHCP
DHCP LEASE RENEWAL PROCESS
This slide illustrates the use of three of the message types discussed in slide 11.
Explain that when a client’s lease period reaches 50 percent expired, it will attempt to contact the DHCP server that provided the lease. When 87.5 percent of the lease period has expired, the client will broadcast a request to any DHCP server in an attempt to renew its lease.

14. WHAT HAPPENS WHEN A CLIENT CHANGES SUBNETS?
Chapter 1: IMPLEMENTING DHCP
WHAT HAPPENS WHEN A CLIENT CHANGES SUBNETS?
This slide illustrates the message types that are used when a client that has been moved initializes and attempts to renew a DHCP lease.
Explain to students that the previous slide illustrates the fact that the client and the DHCP server do not physically move. In some cases, a client might be moved to a different location or department. The new department might use IP addressing information from a different DHCP server that has a scope configured with addresses from a different IP subnet.

15. WHAT IS A DHCP RELAY AGENT?
Chapter 1: IMPLEMENTING DHCP
WHAT IS A DHCP RELAY AGENT?
Routers typically do not forward broadcast traffic; however, DHCP relies heavily on broadcast traffic. To resolve this problem, a DHCP relay agent can be configured on the network segment on which no DHCP server is physically located. The DHCP relay agent will intercept the broadcast message that the router does not forward and can communicate directly with the DHCP server on behalf of the client.
Explain that RFC 1542–compliant routers can forward DHCP traffic and eliminate the need for DHCP relay agents.

16. HOW DOES AUTOMATIC PRIVATE IP ADDRESSING (APIPA) WORK?
Chapter 1: IMPLEMENTING DHCP
HOW DOES AUTOMATIC PRIVATE IP ADDRESSING (APIPA) WORK?
When a client is configured to use a DHCP server but there isn’t a DHCP server available, it uses APIPA.
The range of addresses that APIPA uses is through
Clients that receive an APIPA address will continue to attempt to contact a DHCP server every 5 minutes.

17. ALTERNATE TCP/IP ADDRESS CONFIGURATION
Chapter 1: IMPLEMENTING DHCP
ALTERNATE TCP/IP ADDRESS CONFIGURATION
Alternate address configuration allows you to specify which address the client should use if a DHCP server is not available. The most common use of alternate address configuration is for portable computers that use DHCP in an office and on a home network.
Students sometimes confuse APIPA and alternate configuration.
Demonstrate how to configure alternate address information.

18. AUTHORIZING A DHCP SERVER IN ACTIVE DIRECTORY
Chapter 1: IMPLEMENTING DHCP
AUTHORIZING A DHCP SERVER IN ACTIVE DIRECTORY
Demonstrate how to authorize a DHCP server.

19. Chapter 1: IMPLEMENTING DHCP
WHAT IS A DHCP SCOPE?
A DHCP scope is a range of IP addresses and associated options that a DHCP server has been configured to use.

20. DHCP ADDRESS EXCLUSIONS
Chapter 1: IMPLEMENTING DHCP
DHCP ADDRESS EXCLUSIONS
One of the configuration options for a DHCP scope is address exclusion. When an address is excluded, it is included in the range of addresses, but it is not assigned. An example of an address you might exclude would be the address of a DHCP server or a domain controller.
Explain the difference between excluding an address in DHCP and not including it in the scope.

21. MULTICAST ADDRESS CONFIGURATION USING DHCP
Chapter 1: IMPLEMENTING DHCP
MULTICAST ADDRESS CONFIGURATION USING DHCP
The multicast address range is through
Multicasting provides a method for communicating with members of a multicast group. Multicasting uses a point-to-multipoint communication method. All members of a multicast group have to be configured with the same multicast address.
DHCP on a Microsoft Windows Server 2003 computer supports multicast scopes.

22. Chapter 1: IMPLEMENTING DHCP
DHCP LEASE DURATION
The DHCP lease duration is the amount of time a client can continue to use an address. The default lease period for Microsoft Windows 2000 and Microsoft Windows Server 2003 is 8 days, but you can set it to a value of between 1 hour and 999 days. Explain how you also can set the lease period to unlimited.
Explain when it is appropriate to extend the lease period and when it is appropriate to shorten the lease period.

23. WHAT ARE DHCP CLIENT RESERVATIONS?
Chapter 1: IMPLEMENTING DHCP
WHAT ARE DHCP CLIENT RESERVATIONS?
Client reservations permanently reserve a specific address for a specific client.
Explain how the MAC address is coded into the network card and how the reservation process associates a specific IP address with a specific MAC address. Also, explain how this allows a specific device to receive the same IP address each time it initializes. In addition, discuss how the address that is reserved must be included in the DHCP scope.
Demonstrate how to view the MAC address using the Ipconfig /all command.

24. WHAT ARE DHCP SCOPE OPTIONS?
Chapter 1: IMPLEMENTING DHCP
WHAT ARE DHCP SCOPE OPTIONS?
DHCP scope options can be configured using the New Scope Wizard or by right-clicking the Server Options folder in the DHCP console after the scope has been created.
Define the DHCP option types—server, scope, and reserved client—and describe how they are applied.
User class and vendor class options provide a method of grouping clients, which allows DHCP options to be applied based on the client groupings.
The DHCP administrator creates user classes, and hardware manufacturers define vendor classes.

25. VERIFYING DHCP SCOPE OPTIONS
Chapter 1: IMPLEMENTING DHCP
VERIFYING DHCP SCOPE OPTIONS
Demonstrate how to display the DHCP Options that are configured for a scope in the DHCP console.
Scroll through the option choices and discuss the most commonly used options, such as Default Gateway and DNS Server.

26. ACTIVATING A DHCP SCOPE
Chapter 1: IMPLEMENTING DHCP
ACTIVATING A DHCP SCOPE
After you complete the DHCP New Scope Wizard options, the wizard asks whether you want to activate the scope. You must activate the scope to use the scope. Explain to students that you can activate a scope using the New Scope Wizard, or you can activate it later by right-clicking the scope and choosing Activate from the list of options.
Explain the difference between authorization and activation, and explain when they are required.
Demonstrate to students how to activate a scope if it was not activated using the New Scope Wizard.

27. HOW TO CONFIGURE A DHCP RELAY AGENT
Chapter 1: IMPLEMENTING DHCP
HOW TO CONFIGURE A DHCP RELAY AGENT
Explain that two choices are available on a routed network: you can use a DHCP relay agent, or you can use a DHCP server on each network segment.
Discuss why you must configure the DHCP relay agent with the address of the DHCP server.
Remind students that DHCP relies on broadcast messages and that routers do not typically forward broadcasts.
Demonstrate how to configure the DHCP relay agent under the Routing And Remote Access option in Administrative Tools. It is located under the IP Routing node.

28. WHAT ARE DHCP SUPERSCOPES?
Chapter 1: IMPLEMENTING DHCP
WHAT ARE DHCP SUPERSCOPES?
Superscopes are administrative groupings of scopes that are used to service multinets. Multinets are multiple logical subnets. Explain to students that superscopes contain a list of the member scopes.
Multinets are commonly used when the number of hosts on a network grows beyond the capacity of the original address space.
Explain that a router is necessary to communicate between the logical subnets contained in a multinet.

29. SUPERSCOPES WITH REMOTE NETWORKS
Chapter 1: IMPLEMENTING DHCP
SUPERSCOPES WITH REMOTE NETWORKS
In some cases, a single DHCP server must provide the addressing for multiple subnets, which have a router located between the network segments or between the subnets.
Discuss the issue of having each client receive an address on the appropriate subnet.

30. MULTIPLE DHCP SERVERS ON THE SAME SUBNET
Chapter 1: IMPLEMENTING DHCP
MULTIPLE DHCP SERVERS ON THE SAME SUBNET
In certain situations, multiple DHCP servers exist on the same network segment. The common reason for this is fault tolerance. Remind students of the potential issues associated with broadcast messages, and discuss the possibilities for address allocation when you have overlapping DHCP servers and scopes.
Discuss the advantages of fault-tolerant DHCP servers.

31. Chapter 1: IMPLEMENTING DHCP
SUMMARY
Advantages and disadvantages of DHCP
How to install and configure DHCP
DHCP in an Active Directory network
Scopes and superscopes
DHCP in a routed network