Listen and Watch
Some of prerequisites needed in this unit:

OSI model and TCP/IP stack

IP addressing
Traditionally, network administrators use a notebook where they write which IP, network name and other configuration parameters of each specific device. The main problem with this system is to keep this list updated. The DHCP protocol (Dynamic Host Configuration Protocol) offers an alternative way to configure the network dynamically.
In this unit, you will learn about the dynamic network configuration through a DHCP protocol, as well as when you have to use it.
Listen to this video one time without answering the questions. Just listen to it.
IP Addressing Services VoD CH7 (time 6:53)
Read the following questions. Listen to the video again, and answer the questions.
1. Match these devices with the proper network configuration.
Device Configuration
Server
Laptop
Router
Switch
PC
IP phone
Shared printer
Access point
Static configuration
Dynamic configuration
2. When do you use static configuration ?
I use static configuration when ...
3. When do you use dynamic configuration ?
In the case of … I will use dynamic configuration, because ...
4. What kind of information does the DHCP protocol send? Provide at least 4 answers.
AF_IC02_U1. Dynamic network configuration / Unit 1 1

5. Match these messages with the sending device.
Message Sending device
DHCP DISCOVER
DHCP OFFER
DHCP REQUEST
DHCP ACK
Client
Server
6. Briefly, what are the purposes of the following messages?

DHCPDISCOVER:

DHCPOFFER:

DHCPREQUEST:

DHCPACK:
7. Listen carefully to how the DHCP operation works (1:42 - 4:00), and then fill in the gaps. amount purpose layer binding final accomplished assignment information bound broadcast unicast boot destination assigned locate receives potential
The first step in the DHCP process occurs when a DHCP enabled client boots. During the
________ process the client sends a broadcast DHCP discover message. The ________ of this message is to ________ a DHCP server and begin the DHCP address ________ process.
After receiving the DHCP discover message from a client the DHCP server replies to that specific client with the ________ DHCP offer message. You may be wondering how the DHCP server sends a unicast message containing IP ________ to a client that does not have an IP address. The answer is in ________ 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 ________ address in the offer message before sending the offer message. Before sending the offer message, the server places in 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 ________ the DHCP offer from the server it must then accept the offer. This is
________ by the client sending a DHCP request message to the server. This message is a
________ 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 ________ Second, the message is a broadcast so it notifies other ________ 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 ________ confirmation that IP configuration has been ________ 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 ________ 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________.
AF_IC02_U1. Dynamic network configuration / Unit 1 2

8. According to the Cambridge Dictionary definition of the noun lease , explain with your own words this concept related to DHCP service.
What we understand for lease time is ...
Lease : a legal agreement in which you pay money in order to use a building, piece of land, vehicle, etc. for a period:
He has the house on a long lease.
The lease runs out/expires in two years' time.
We signed a three-year lease when we moved into the house.
Definition of lease (Cambridge Dictionary)
9. What are the 3 steps in order to configure a DHCP Server?
10. What parameters can be given to a client through the DHCP service? List them.
11. According to the Cambridge Dictionary definition of the verb relay , explain with your own words the concept of DHCP relay.
Relay : to repeat something you have heard, or to broadcast a signal, message, or programme on television or radio:
I was told the news first and then I relayed it to the others.
TV pictures of the war were relayed around the world by satellite.
Definition of relay (Cambridge Dictionary)
12. Who performs the relay action?
The relay action is pe rformed by …
AF_IC02_U1. Dynamic network configuration / Unit 1 3

The DHCP server can provide IP addresses in several ways. These address allocation mechanisms are:

Manual Allocation : Pre-allocated IP addresses are assigned to the client through the
DHCP service.

Automatic Allocation : Available IP addresses from the pool of the DHCP service are assigned to the client. There is no lease time, that is, they are assigned permanently to the device.

Dynamic Allocation : Available IP addresses from the pool of the DHCP service are assigned to the client. This time, however, they are assigned for a certain period of time.

Hybrid : any combination of the above.
TO KNOW MORE
If you want to know more about DHCP allocation mechanisms, take a look at the following document:
DHCP Overview
1. Could you imagine a way to pre-allocate IP addresses from the server? Hint: the server must uniquely identify a device.
2. Define a scenario and provide an example for every address allocation mechanism.
AF_IC02_U1. Dynamic network configuration / Unit 1 4