(Latest revision 01/23/2001)
01/23/2001: Changed some addresses for the traceroute problem -- problem 1.
01/23/2001: Made some simplifications of problem 2.
01/28/2001: More conditions on some of the problems.

THIRD HOMEWORK ASSIGNMENT FOR CS 3000

Homework Assignment #3

1. Run the following traceroute commands and turn in a copy of the output they produce. (This problem is akin to #21.4 in Comer/Droms) 
traceroute www.calstate.edu
traceroute ucsd.edu
traceroute www.whitehouse.gov
traceroute cs.harvard.edu
traceroute u-aizu.ac.jp
2. Run the command 
ps -ef
on altair. Make a copy of the output. Find at least ten processes in the list that you are sure are servers. Under each line corresponding to one of your servers place a comment that marks the process as a server and states facts and evidence that prove it is a server. Turn in this edited output.

( Some help: Prepare for doing this problem by first reading the chapter in our text about client-server interaction. In the readout from the ps -ef command, look for processes owned by root whose names end in 'd'. Scan the first few lines of the man pages for these programs. To find out if a program is listening on a port, do the rpcinfo command and cat the /etc/services file. You can do man services or man rpcinfo to get more information, or ask about these things in class. Using this information, you should be able to verify that many of the running processes are servers.)

3. Do problem 24.3

4. Do problem 25.1 in Comer/Droms.

For 25.1, be sure to contact servers on several different hosts. Don't contact only Sun Ultra's. Try some other hosts such as koko, yokuts, or ollie. Try a host or two in a different timezone. Try at least four hosts. Turn in a script showing the computer interaction you had when doing problem 25.1.

5. Do 26.9 in Comer/Droms. If you like use the directions for the lab on nslookup in the web space to help figure out what to do with nslookup. Set the querytype to PTR when you look up:

1.2.10.128.in-addr.arpa.

(Don't leave out the final period above.) Set the querytype to A when you look up:

arthur.cs.purdue.edu.

(Again, do not leave out the final period when you do the look up.) With your answer, include a script showing your session with nslookup. For full credit, you must succeed with both of the queries, and you must give an enlightening explanation of the results. You can ask me for help if you have difficulty.

6. Telnet to ishi, port 25. The command is:

telnet ishi.csustan.edu 25

What program answers? Enter: 

EXPN cs3100

What happens? Next try: 
EXPN john

and: 

EXPN cs4440

What is the meaning of the output? End the telnet session by typing: 

QUIT

Include a script of the session.

7. Do a version of problem 28.8 in Comer/Droms:

Prepare for this by first ftp'ing into www.cs.csustan.edu with the ftp command:

ftp www.cs.csustan.edu

When prompted for your "Name" enter ftp (not your login name). When prompted for "Password," enter your full e-mail address. Once you are logged in enter the command dir and you will be shown the listing of the root ftp directory. Save the names you see somewhere. Then disconnect by typing bye.

Next, telnet to port 21 on www.cs.csustan.edu. Once connected enter user ftp and then enter pass plus your complete e-mail address. This will get you logged in.

Next enter help. You will see a list of commands available. Use your ingenuity and do some experimenting. For full credit, you must: If you want you can ask me for some help or guidance. Turn in a script showing both interactions: the one for the "ftp www.cs.csustan.edu" command and also the one for "telnet www.csustan.edu 21" .

8. Do problem 29.5 in Comer/Droms. Include a copy of the document.