SI110 Homework Alpha: ________ Name: __________________ Page 1 of 3
Collaboration Policy: Default MIDN Last, F. choose one: □ None □ XS110 □ EI with:
(or more) □ MGSP □ Discussed with: ______________________
Homework: /SI110/Cyber Battlefield/Networking – Apps & Nuts and Bolts
1 [ 10 / 8 / 5 / 0 ] On the left are listed three ways of identifying computers for network communication. Match them to a correct description from the right:
Answer Description Identifier
Used by the Network Layer to identify a host. a. Domain Name
Easy for users to remember, cannot be used by lower layers to identify hosts or devices.
Used by the Link Layer to identify a device or an interface. b. IP Address c. MAC Address
2. [ 20 / 15 / 10 / 0 ] You need to know that: port 22 is for SSH, port 53 is for DNS, port 80 is for
HTTP, and port 443 is for HTTPS; otherwise you do not need to memorize the ports associated with different services. What you do need to memorize, however, is what protocols go with what services and the tool associated with a service from the table in your notes. Complete the following table:
Protocol Service Tool
HTTP
Secure remote shell ssh ( PuTTY )
DNS
SMB
Get an IP Address on the fly
Secure web traffic
Client built-in to Windows rdesktop (UNIX client)

SI110 Homework Alpha: ________ Name: _______________ Page 2 of 3
Go to the demo page: (SI110

Resources

Network Demos

Network/Inter-network Demo) http://rona.academy.usna.edu/~si110/resources/netdemo/Networking.html
Click on Host 2, then click on Host 3, to send a message from Host 2 to Host 3. Step carefully through the demo reading the results of each step. Use the demo to answer Questions 3-4.
3. [ 10 / 8 / 5 / 0 ] The first thing Host 2 must do is: (Circle answer) a. Look up the MAC address of Host 3 to see if Host 3 is on the same network. b. Use Host 2’s subnet mask to determine if Host 2 and Host 3 have the same network address. c. ping Host 3 to see if Host 3 is connected to the Internet. d. traceroute to Host 3 to see how many hops away Host 3 is.
4. [ 10 / 7 / 4 / 0 ] When Host 2 creates the packet for transmission across the network, what should the destination MAC address be? (Circle answer) a. The MAC address of Host 2 b. The MAC address of Router 2 (Host 3’s Gateway Router) c. The MAC address of Host 3 d. The MAC address of Router 1 (Host 2’s Gateway Router)
5. [ 20 / 15 / 10 / 0 ] Consider the following three hosts.
Host
IP Address
X
10.16.20.18
Y
10.16.20.1
Z
128.180.2.57
Subnet Mask
Gateway Router
255.255.255.0
10.16.20.1
255.255.255.0 255.255.255.0
MAC Address D0-67-E5-18-20-06 6C-50-4D-20-15-FE 00-00-A2-19-98-90
If Host X wants to send the message "33 – 11 = SSH" to Host Z, which of the below describes what X sends to its switch? Circle your answer and explain below; use complete sentences.
Answer Destination MAC Destination IP Message a. D0-67-E5-18-20-06 128.180.2.57 33 – 11 = SSH b. 6C-50-4D-20-15-FE 10.16.20.1 33 – 11 = SSH c. 6C-50-4D-20-15-FE 128.180.2.57 33 – 11 = SSH d. 00-00-A2-19-98-90 128.180.2.57 33 – 11 = SSH

SI110 Homework Alpha: ________ Name: _______________ Page 3 of 3
6. [ 10 / 7 / 4 / 0 ] Consider the following hosts:
Host A
IP Address
Subnet Mask
161.75.1.11
255.255.252.0
B
161.75.1.236
255.255.255.0
C
161.75.5.235
255.255.255.0
Use the Network Address Calculator found on the course Resources page to answer the following: Are any of these hosts on the same network? Explain exactly how you arrived at your answer!
7. [ 20 / 15 / 10 / 0 ] Perform the following in an Administrator shell, after reviewing the student notes regarding tracert and arp .
1.
Perform a tracert from your host to a roommate’s host while both of you are in your room.
2.
Perform another tracert to a classmate’s host NOT in your company.
3.
Enter the command arp -a into your shell to display your host’s ARP table.
Question Answer
How many hops from your host to your roommate’s host?
Is the IP address for your roommate’s host in your ARP table?
Yes / No
How many hops from your host to the classmate in another company’s host?
Is the IP address for the classmate in another company in your ARP table?
Yes /
Based on these results, why are the tracert results different? Hint: Recall the
Network/Inter-network Demo, and consider performing a network address calculation.
No