CIS456-HTML: Exams

• Please answer all (30) questions in essay format and be as detailed as you feel is necessary (HINT!) All answers must be submitted to me via e-mail by 12 midnight, May 5, 2000.

• There are two extra credit questions which may also be done, but not exchanged for the original (30).

• All late material WILL BE PENALIZED! All answers must be in your own words (not taken from my lessons or from other students).

• Scope: Lessons (20...28)

Chapter 20 (Lesson 21, Lesson 22)
1. How would a programmer setup a TCP network connection over which to transfer data from an SMTP server? Explain the socket calls and steps.

2. Why are multiple socket read and write calls provided in the BSI Socket API? What functions do they perform differently from each other?

3. Detail the differences between a stateful and stateless client/servers using connectionless and/or connection-oriented protocols and sockets.

4. Provide the socket calls which correspond to the steps taken by concurrent FTP server. You must pseudo-code all calls required including: the gethostname, hostent structure setup, etc. (See the examples provided in the slides)

   Chapter 21 (Lesson 23)

5. The BOOTP message format is inconsistent because it has two fields for client IP address and one for the name of the boot image. If the client leaves its IP address field empty, the server returns the client's IP address in the second field. If the client leaves the boot file name field empty, the server replaces it with an explicit name. Why?

6. When a BOOTP client receives a reply via hardware broadcast, how does it know whether the reply is intended for another BOOTP client on the same physical network?

7. When a machine obtains its subnet mask with BOOTP instead of ICMP, it places less load on other host computers. Explain why this is so.

8. Consider a host that has a disk and uses DHCP to obtain an IP address. If the host stores it's address on disk along with the date the lease expires, and then reboots within the lease period, can it use the address? Why or why not?

9. Can DHCP guarantee that a client is not "spoofing" (i.e., can DHCP guarantee that it will not send configuration information for host A to host B)? Does the answer differ for BOOTP? Why or why not?

10. Can a computer that uses DHCP to obtain an IP address operate a server? If so, how does a client reach the server?

    Chapter 23 (Lesson 24)

11. What is a remote procedure call? How and where is it used within the NFS service?

12. Use a TELNET client to connect your keyboard and display to the TCP protocol port for echo or chargen on your local system to see what happens. (i.e., Telnet 128.235.251.100:7) NOTE: Not all telnet clients will allow you to specify a port, so do try several different telnet applications (including PC-base ones if need be). If you are unable to get this to work (after asking for help), then please perform a traceroute to www.micromuse.com instead.

13. Explain the Network Virtual Terminal specification that the TELNET standard defines. What is it used for? Also, what other TCP/IP standard application protocol uses this NVT and how?

14. Perform a Traceroute to www.njit.edu from any country oversees (France, Germany, etc.) and provide the results as well as an explanation as to what was returned.

    Chapter 24 (Lesson 25)

15. Why should file transport protocols compute a checksum on the file data they receive, even when using a reliable end-to-end stream transfer protocol like TCP?

16. What happens in FTP if the TCP connection being used for data transfer breaks, but the control connection does not?

17. What is the chief advantage of using separate TCP connections for control and data transfer? (Hint: think of abnormal conditions).

18. How does the Network File System (NFS) compare with commercial, proprietary network operating systems? What functionality does it provide and which components of it are used?

    Chapter 25 (Lesson 26)

19. Some mail systems force the user to specify a sequence of machines through which the message should travel to reach its destination. The mail protocol in each machine merely passes the message on to the next machine. List three disadvantages of such a scheme.

20. What are and why are mail gateways used? What purpose do they serve and how do they effect reliable mail delivery systems?

21. How does one setup an e-mail alias name? Explain the steps and information required.

22. Explain how a web server uses MIME types to identify data types, and then how a web client/browser uses them for display.

    Chapter 26 (Lesson 27)

23. How do Internet and Network management schemes and responsibilities differ?

24. Explain the reasoning behind ASN.1 and XDR.

25. SNMP version 3 has recently come out, research it and explain the differences between SNMP version 1, version 2, and now version 3. Just simply compare 2 to 1, and 3 to 2, and give the features. (You will need to find this information on the Internet to answer this question)

26. The OSI model separates the responsibilities of applications from having to handle "sessions" and "presentation" functionality. TCP/IP, however divides these responsibilities among TCP and application protocols, making them more complex. Which is a better approach and why? Give your opinion and back it with technical facts.

    Chapter 28 (Lesson 28)

27. Many sites that require all file transfers to go through a bastion host arrange for the file transfer software to scan the file before admitting it into the organization. Why do organizations scan files? (Hint: think of importing programs that run on personal computers)

28. What are proxitized applications and how do they differ from normal applications?

29. Give two reasons why the group of people who administer an organization's security policies should be separate from the group of people who administer the organization's computer and network systems.

30. Some organizations use firewalls to isolate groups of users internally. Give examples of ways that internal firewalls can improve network performance, and examples of ways internal firewalls can degrade performance.

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    Extra Credit

31. Extra Credit Question

    Answer the following questions sincerely and honestly to get the extra credit points. You must answer all questions and explain yourself well.

    • Which topic/lesson did you find most useful in this course? Why?
    • Which topic/lesson was your favorite? Why?
    • Was the book helpful?
    • Which project did you find most helpful? In what ways?
    • If you used the videos, did they teach at a reasonable pace? Please elaborate.
    • Which topic/lesson/area(s) of study was least helpful or interesting? Why?
    • Do you feel this course effected your academic performance it in any way (good or bad)?
    • Do you feel you've gained any marketability in the computer or networking industries? In what areas and why?
    • Was there anything you would've like seen added to the course or changed?
    • What is your honest opinion on the take-home examinations?
    • Should there have been more hands-on exercises mixed in with the materials?
    • What are your opinions on our web site (CIS456-HTML) ?
    • Please give any general feedback you would like.

Last Modification: (Tuesday, April 18, 2000)

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