Activity $2$: EXPLORING REAL$-$LIFE DHCP IP ADDRESS ALLOCATION PROCESS.

Background

The DHCP assigns IP addresses along with network parameters. The ipconfig Windows command and its variations can be used to explore the DHCP process.

$-$Objective

To test the knowledge of how DHCP works, using ipconfig command and its variation to enable a DHCP exchange.

Requirements

Textbook

Internet connectivity.

Download and install Wireshark.

Tasks

Step $1$: On your computer, open a Command Line Window, type command ipconfig and let it run. Scroll to the section showing your active network interface$/$adapter $($e$.$g$.,$ Ethernet or Wi$-$Fi$).$ Take a SNIP of the network parameters $($information$)$ that is provided. An example is as below:

Nireless LAN adapter Wi$-$Fi:

Connection$-$specific DNS Suffix $.$ : tds

Link$-$local IPv$6$ Address $....$ : fe$80$::$1$c$42$:$6782$:$65$cf:eba$3\%6$

IPv$4$ Address. $.........$ : $192\mathrm{.}168\mathrm{.}0\mathrm{.}8$

Subnet Mask $...........$ : $255\mathrm{.}255\mathrm{.}255\mathrm{.}0$

Default Gateway $.......$ : $192\mathrm{.}168\mathrm{.}0\mathrm{.}1$

Now, on the CLI type ipconfig$/$all$.$ Scroll to the section showing your active network interface$/$adapter $($e$.$g$.,$ Ethernet or WiFi$).$ Take a SNIP of the network parameters $($information$)$ that is provided.

a$)$ Provide the two SNIPs showing the information generated by each of these two commands for your active network interface. $(4$ points$)$

b$)$ List two similarities and two differences that you observed in the use of the two Windows CLI commands $($Hint: examine the outputs$).(4$ points$)$

Step $2$: Start Wireshark, go to the active network interface $($adapter$)$ on your computer.

a$)$ Begin capturing and keep Wireshark running.

b$)$ Go back to the CLI Window, then issue the command ipconfig$/$release$.$ Let the command run till it ends. Then issue the command ipconfig$/$renew and let it run till the end. Now, issue the command ipconfig$/$all$.$ Scroll to your active network interface that you used in Step $1.$ You should be able to view the DHCP newly assigned IP address for your device and the associated assignment date should be the date you performed this activity. Take a SNIP of the window, circle the information about the Lease Obtained and Lease Expires. Provide the SNIP on your worksheet. $(3$ points$)$

c$)$ Now go back to the Wireshark window, stop capturing, and save the file. Examine your Wireshark capture output, you would have captured a lot of traffic. However, only DHCP traffic is relevant for this activity. Filter the DHCP packets using the appropriate display filter syntax. Examine the DHCP exchanges, take note of the occurrence of the DORA process. Export the DORA packets to a Plaintext file named "Your Initials$-$DHCP$\_$DORA". Upload the Plaintext file for grading. $(3$ points$)$

Step $3$: Use the saved Wireshark file to answer the following questions.

a$)$ How many packets were involved in the DORA process? $(2$ points$)$

b$)$ What is the transaction ID for the DORA process? $(1$ point$)$

c$)$ Which transport layer protocol and port numbers were used during the DORA process? $(2$ points$)$

d$)$ Take a SNIP of the Wireshark output, circle where you got ALL the information you gave for questions $a,b,$ and $c$ above. Provide the SNIP on your worksheet. $(2$ points$)$

e$)$ Develop a flowchart that describes how the DORA packet exchange process works. $(6$ points$)$

f$)$ From what you have studied about DHCP in this course, a packet is sent by DHCP servers in response to the first packet sent by the DHCP client. What is this packet called? $(2$ points$)$

g$)$ Identify the packet in question $f$ on the filtered window. Click on the packet and go to the Packet Details pane. Examine all the options that were used. How many options were used? $(4$ points$)$

h$)$ Expand ALL the options to view the network parameters that were used in the identified packet. Provide a SNIP of all these options showing the network parameters. $(3$ points$)$

i$)$ Compare the network parameters on the SNIP in question $h$ with the network parameters on the SNIP taken from the ipconfig$/$all CLI command in Step $1.$ List the similarities in the parameters. $(3$ points$)$