Are DHCP messages sent over UDP or TCP? 2. Draw a timing datagram illustrating t

Question

Are DHCP messages sent over UDP or TCP?

2. Draw a timing datagram illustrating the sequence of the first four-packet
Discover/Offer/Request/ACK DHCP exchange between the client and server. For each packet, indicated the source and destination port numbers. Are the port
numbers the same as in the example given in this lab assignment?
3. What is the link-layer (e.g., Ethernet) address of your host?

4. What values in the DHCP discover message differentiate this message from the
DHCP request message?

5. What is the value of the Transaction-ID in each of the first four
(Discover/Offer/Request/ACK) DHCP messages? What are the values of the Transaction-ID in the second set (Request/ACK) set of DHCP messages? What is
the purpose of the Transaction-ID field?

6. A host uses DHCP to obtain an IP address, among other things. But a host’s IP
address is not confirmed until the end of the four-message exchange!If the IP address is not set until the end of the four-message exchange, then what values are
used in the IP datagrams in the four-message exchange? For each of the four DHCP messages (Discover/Offer/Request/ACK DHCP), indicate the source and
destination IP addresses that are carried in the encapsulating IP datagram.

7. What is the IP address of your DHCP server?
8. What IP address is the DHCP server offering to your host in the DHCP Offer message? Indicate which DHCP message contains the offered DHCP address.
9. In the example screenshot in this assignment, there is no relay agent between the host and the DHCP server. What values in the trace indicate the absence of a relay
agent? Is there a relay agent in your experiment? If so what is the IP address of the agent?
10. Explain the purpose of the router and subnet mask lines in the DHCP offer message.
11. In the DHCP trace file noted in footnote 2, the DHCP server offers a specific IP address to the client (see also question 8. above). In the client’s response to the

Explanation / Answer

Answer :

1) In general the DHCP messages sent over UDP.

3)The ethernet address of my host is 00 : 27 : 0e : 21: e0 : 8a

4)The value which differs from the discover and request is message type field.The request also includes a server identifier field.In other words the message type value for a discover message is one but the message type value for a request packet message is different one.This is how we can differentiate.

5)The transaction ID for first set of messages is 0x6fd4f5cc and for
second set of messages is 0x53a63290.The transaction ID is different number which is randomly generated so that the host can differentiate between different requests made by the user.

6)Discover Source: 0.0.0.0    Discover Destination:255.255.255.255
Offer Source : 192.168.1.1    Offer Destination : 255.255.255.255
Request Source : 0.0.0.0    Request Destination :255.255.255.255
ACK DHCP:192.168.1.1    ACK Destination :255.255.255.255

7)The ip address of DHCP server is 192.168.1.1

8)The DHCP server offers 192.168.1.14 as the ip address in DHCP offer message.The offer message contain DHCP address offered by the server.

9)The ip address existence as 0.0.0.0 which indicates the absence of a relay agent. There is no relay agent in our experiment.

10)The purpose of subnet mask line is that it tells the client which subnet mask are available and to use.
The purpose of router line indicates where the client should send messages i.e internet gateway by default.

11)The client accepts the IP address given in the offer message within the request message. The ip address being offered 192.168.1.101 in the offer message client revert back a message for further requesting that particular IP address.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.