SI110 Homework Alpha: ________ Name: ____________________
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Collaboration Policy: Default
choose one: □ None □ XS110 □ EI with:
(or more)
□ MGSP
□ Discussed with: ____________________________
Homework: /SI110/Cyber Battlefield/Networking – Layers and Translations
1. [ 20 / 15 / 10 / 0 ] Match the TC/IP Stack layer to the service description it is associated to.
Answer
Description
TCP/IP Stack Layer
Routes packets through different networks
a. Application Layer
Transfers data over wires or through radio
waves
b. Transport Layer
Services for users
c. Internet Layer
Moves packets between hosts in the same
network
Moves data from a process on one host to the
process on another host.
d. Link Layer
e. Physical Layer
2. [ 20 / 15 / 10 / 0 ] Suppose you gave a netstat -a command on a given computer, and
viewed the network connections. For each example below, circle Yes or No for whether it could
"make sense" to see such a connection on that computer, based on examining the port numbers
and IP addresses. Assume your laptop is at USNA, and that you don't have any unusual software
running on your laptop.
On Your Laptop
Yes / No
Local
Remote
10.22.20.18:53
10.1.74.10:42000
Yes
/
No
10.22.20.18:42000
10.1.83.17:22
Yes
/
No
10.22.20.18:31337
128.194.138.74:80
On rona
Yes / No
10.1.83.17:22
10.22.20.15:42015
Yes
/
No
10.1.83.17:54321
199.204.164.47:80
Yes
/
No
10.1.83.17:80
10.22.20.17:42017
Local
Remote
3. [ 20 / 15 / 10 / 0 ] Thoroughly review the Network Address Translation demo at:
http://rona.academy.usna.edu/~si110/resources/netdemo/privateIP.html
In the demo, if Host 10.24.126.7 opens a shell and enters the command netstat -an after
sending the get request to foobar.com, what entry would likely appear? Hint: Use nslookup
and netstat -an in an Administrator shell to assist before and after visiting amazon.com.
Circle your answer.
a.
b.
c.
d.
e.
TCP
TCP
TCP
TCP
TCP
10.24.126.7:32143
10.24.126.7:80
10.24.126.7:47688
10.24.126.7:32143
10.24.126.7:32143
64.233.160.9:80
64.233.160.9:32143
64.233.160.9:80
131.121.226.100:80
131.121.226.100:47688
ESTABLISHED
ESTABLISHED
ESTABLISHED
ESTABLISHED
ESTABLISHED
SI110 Homework
Alpha: ________
Name: ____________________
Page
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4. [ 20 / 15 / 10 / 0 ] In your own words describe the security benefits of employing Network
Address Translation on a network. Use complete sentences, spelling and grammar count.
5. Midshipman X and Midshipman Y point their browsers at www.ipchicken.com at the same
time. What each of them sees is shown below.
Midshipman X sees this
Midshipman Y sees this
a. [ 10 / 5 / 0 ] The IP Address of the USNA server that's doing the network address translation is
_________________________________.
b. [ 10/ 5 / 0 ] The
www.ipchicken.com webserver sends
the packet shown here back to USNA.
This packet is being sent back to
which host? (i.e. is it MIDN X or
MIDN Y)? How do you (and, more
importantly, the network address
translation server!) know?
From:
198.41.206.97
Port 80
To:
136.160.90.132
Port 33886
Data:
HTTP/1.1 200 OK
Date: Tue, 18 Feb 2014
18:13:32 GMT
Server: Apache/2.2.25
Content-Type:
text/html
SI110 Homework
Alpha: ________
Name: ____________________
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