AF_IC02_GUIDE. Dynamic network configuration
Teacher’s guide
1. Objectives
The objectives (general and/or specific) of this unit are:
 Know the new concepts and terms
 Distinguish between static and dynamic network configuration
 Understand how the DHCP protocol works and its features
 Choose the appropriate address allocation mechanisms
 Read texts related to LAN and DHCP configuration
2. Use of materials and recommendations for teachers
We strongly recommend doing the exercises at the same time the contents are explained, and
leave the practice to the end of the unit. In the case of the activity Unit 2. Professional terms we
encourage students to perform this task throughout the different units.
3. Methodology
Two different methodologies are used. The first one is to explain the contents and then do some
exercises to understand better what has been explained. The second one is to understand
some new concepts more in depth and learn them through practice.
4. Evaluation
This unit is evaluated on 3 areas:
 30% for activities
 40% for the practice.
 30% for a final exam that summarizes all units
Each area has no minimum grade, so the student has to know in which area he is stronger and
do his best to compensate for weaknesses in other areas.
5. Other considerations
Verify the prerequisites needed for this unit with students, especially OSI and TCP/IP stack, and
IP addressing.
6. Answers key
Unit 1
Question 1
 Static configuration: Server, Router, Switch, Shared printer, Access point
 Dynamic configuration: Laptop, PC, IP phone
Question 2
Devices whose locations are not likely to change, normally because they share some
service
Question 3
Devices whose locations are likely to change, or devices that do not share any service
AF_IC02_Dynamic Network Configuration / Teacher’s guide
1
Question 4
 IP address
 Gateway address
 Subnet mask
 DNS server address
Question 5
 Client: DHCP DISCOVER, DHCP REQUEST
 Server: DHCP OFFER, DHCP ACK
Question 6
 DHCPDISCOVER: message for discovering DHCP servers
 DHCPOFFER: message for knowing there is a DHCP server who offers IPs
 DHCPREQUEST: message for requesting an IP
 DHCPACK: message for sending a network client configuration (IP, mask…)
Question 7
The first step in the DHCP process occurs when a DHCP enabled client boots. During
the boot process the client sends a broadcast DHCP discover message. The purpose of
this message is to locate a DHCP server and begin the DHCP address assignment
process.
After receiving the DHCP discover message from a client the DHCP server replies to that
specific client with the unicast DHCP offer message. You may be wondering how the
DHCP server sends a unicast message containing IP information to a client that does
not have an IP address. The answer is in layer two information. When the DHCP server
receives the broadcast discover message from the client, it uses the Source MAC
Address of that message as the destination address in the offer message. Before
sending the offer message. Before sending the offer message, the server places an ARP
entry into its ARP table that links the offered IP address and the MAC Address of the
client that sent the discover message.
After the client receives the DHCP offer from the server it must then accept the offer.
This is accomplished by the client sending a DHCP request message to the server. This
message is a broadcast and conserves two purposes. First, it enables the client to get
there occasions from the server that indeed it was a specific IP address that was
assigned. Second, the message is a broadcast so it notifies other potential DHCP
servers that the client has accepted a DHCP address from a specific server, and in effect
declines offers from other servers.
The final message that is sent in the DHCP process is the unicast DHCP acknowledge
message sent by the DHCP server. The DHCP acknowledge message serves as the
final confirmation that IP configuration has been bound to a DHCP client. After the
acknowledgement is received by the client it begins using the IP configuration
information to function in the network. The amount of time that the client uses the IP
information depends upon the lease time, which is configured on the server by a network
administrator and supplied to the client at the time that the address binding.
Question 8
The amount of time you can keep an IP
Question 9
1. Define a range of addresses
2. Create the DHCP pool
3. Configure the parameters of the pool
Question 10
AF_IC02_Dynamic Network Configuration / Teacher’s guide
2
 IP address
 Gateway address
 Subnet mask
 DNS server address
 Lease time
 Max lease time
Question 11
To broadcast a message outside a network
Question 12
The relay action is performed by a router
Unit 3
Several answers are possible. Some notes:
 IPs must be private, except the one that belongs to the WAN (one interface of the
main router).
 Routers must have 2 IPs.
 Servers, switches (optional), access points, shared printers and a computer with a
shared printer must have a static IP. The other devices use dynamic configuration.
 As there are 2 networks, IPs from 2 ranges must be used.
Unit 6
Short answers:
1. dynamic host configuration protocol
2. dhcpdiscover
3. manual
4. automatic
5. dynamic
6. hybrid
7. dhclient
8. ipconfig /renew
Multiple choice (multiple correct answers): d, bd, cdfh, ace
AF_IC02_Dynamic Network Configuration / Teacher’s guide
3