SI110 Homework Alpha: ________ Name: ___________________ Page 1 of 2
Collaboration Policy: Default
MIDN Last, F.
choose one: □ None □ XS110 □ EI with:
(or more)
□ MGSP
□ Discussed with: ______________________
Homework: /SI110/Cyber Battlefield/Networking - Ports
1. [ 20 / 15 / 10 / 0 ] TCP and UDP are two Transport Layer protocols. For each description
below, circle which of the protocols is/are described:
Protocol
Description
TCP / UDP a. Provides communication between processes on different hosts.
TCP
/
UDP
b. Establishes a connection, then hosts communicate via the connection.
TCP
/
UDP
c. Is unreliable, i.e. data may be lost or arrive out of order.
2. [ 25 / 20 / 10 / 0 ] Using the list of service-to-ports mappings link in the lecture notes, answer
the following questions:
Question
Answer
a. What port is used for SMTP (Simple Mail Transfer Protocol)?
b. Does SMTP use TCP or UDP?
c. What port does the Domain Name Service use?
d. What protocol uses port 123?
e. What port does the RDP (Remote Desktop Protocol [Windows]) use?
3. [ 25 / 20 / 10 / 0 ] In your own words describe why the answer to 2.b. makes sense; i.e. what is
it about the other Transport Layer protocol that makes it less desirable for email? Use complete
sentences; spelling and grammar count.
4. [ 10 / 8 / 5 / 0 ] Putting this URL http://www.w3.org/ in your browser's address bar is the
same as putting in … (circle answer)
a. http://www.w3.org:80/
b. http://www.w3.org:22/
c. http://www.w3.org:42/
d. None of the above
5. [ 10 / 8 / 5 / 0 ] A web server always has to listen on the default HTTP port in order to
communicate using HTTP? Circle an answer.
True / False
SI110 Homework
Alpha: ________
Name: ___________________
Page 2 of 2
6. [ 10 / 8 / 5 / 0 ] As you know rona is a web server and an SSH server, there are other services
running on rona. Specifically, there is a simple TCP server listening on port 51110. The service
is expecting your alpha number as the request message (input). Use netcat (nc) from your laptop
or from rona to send your request to the service on port 51110 and write your code below
(output). Note: This service validates input, invalid input will result in an error message being
returned; you are not looking for an error message.