Notes on Using the Lab for CS 3230 Students

Location

Where do I find the lab? Bottom floor of the TB bldg on a regular basis. Occasionally, we might need to meet elsewhere. This would be either the 2nd floor of the TB bldg, or more likely the computer lab in the new Science bldg on the West side of the campus. Update [1/19/98]: It looks like we'll be able to use the lab in the new Science building on a regular basis. Oh joy.

Telnet Is Your Friend

How does one use the lab machine? Follow these simple instructions:

1. Local Login: If you are at a Linux or NT machine in the lab, you need to log in to it locally with the username "Weber" (not case sensitive, i.e. "weber", "WEBER", or "wEbEr" will do just fine) and the password "tires" (as in the four rubbery things on the bottom of a car--probably case sensitive).

   Note: If you are logging in from home, you will need to dial up to your ISP first, then you can telnet in as per the next step.

   Additional Note: If you are logging in from anywhere else (i.e. work, the library, some "Internet Cafe" etc.) you will need to go through whatever steps are necessary to get a local login and gain access to the outside world. You should be getting the idea at this point that you need to get on the Internet to access the lab server.

2. Invoking Telnet: The next step is to telnet into the Zonker server. This is accomplished by typing at the command line: telnet zonker.cs.slcc.edu. Alternatively, you might use the IP address by typing: telnet 144.35.6.10. It should tell you that it's trying to connect, and then present you with a login prompt once it's connected.

   Those of you who are telneting in from a non-command-line based environment will need to enter the appropriate information into whatever application you are using. Just be sure you get the name or the IP address right (that's the 144.35.6.10 thingy) and it should work just fine.

3. What to do at the Login: At the login prompt, you will need to enter your username, which is arranged thusly: UP TO the first 6 (six) letters of your first name, followed by UP TO the first two letters of your last name.

   Example #1: My name is Robert Frost. My login name is: robertfr.

   Example #2: My name is Lao Tzu. My login name is: laotz. Note that because my first name is only three letters long, my username is shorter. There is no need to feel cheated.

   Please note that the username is all lower case. Everyone get it? I sure hope so.

4. What to do at the Password: Right after you log in, you will be greeted with a password prompt. If this is your first time logging into Zonker (i.e. you did not have an account created already from a previous class) your password, for the time being, is the word "summer". If you care at all about the security of the network (and you should) you will change your password immediately after you log in for the first time. Instructions on how to do this will follow.

5. Getting into the right directory: Right after you log in, you will be in your home directory. This is NOT the directory where you will need to put assignments. Type 'cd public_html' and you will arrive in the propper directory. In here you will put all of your web pages, and Java applets. CGI programs will go in the cgi-bin directory, but you don't need to worry about that until much later in the semester.

6. Logout: Once you're done doing what you need to do, type exit at the command line to disconnect and leave.

Telnet Example:

The following is a real-world example of a telnet session in action:

[mwhitley@listserv mwhitley]$ telnet 144.35.6.10 
Trying 144.35.6.10...
Connected to 144.35.6.10.
Escape character is '^]'.

Red Hat Linux release 5.0 (Hurricane)
Kernel 2.0.33 on an i486
login: markw
Password: 
Last login: Tue Sep  8 12:01:25 from 204.246.137.2
[markw@zonker markw]$ 

Note that the password was not displayed when I typed it. This is a security feature. Note also how the last line is a shell prompt with the word zonker in it. This means I've arrived. At this point, you can type shell commands to perform actions. Keep your old UNIX notes handy.

Changing Your Password

One of the first things you should do when you log in to the server for the first time is change your password. This is accomplished by doing the following:

1. type passwd at the command line and hit return.
2. You will be prompted for your old password. Type it and hit return.
3. You will then be asked to type your new password. Enter a new password and hit return. Note: If you type an easily-guessed password, it will tell you so and make you go back and pick a more clever password. Use some digits as well as numbers and make your password around, oh, say 8 letters long.
4. You will then be asked to confirm your new password by typing it again. Do so, and hit return. Your password is now changed.
5. Do your very best not to forget your new password. This is best accomplished by writing it down someplace.

The following is an example of a password change in action:

[markw@zonker markw]$ passwd
Changing password for markw
(current) UNIX password: 
New UNIX password: 
Retype new UNIX password: 
passwd: all authentication tokens updated successfully
[markw@zonker markw]$

That word "successfully" means that it worked.

FTP Is Your Friend

How do I upload files to the server? Some of you will be doing your homework assignments from home, from work, or from some location other than the lab computer. This means that eventually, you will have to send files to the server. I know this is the case, because that is the only way I will accept your homework. Follow these simple steps to accomplish the task:

1. Getting connected, and logging in: Basically, all you need to do to get connected is follow the same steps you used for telnet (above) except instead of typing telnet you will type ftp instead. Just as it says in the instructions above, you will be required to enter a username and password to log on to the network.
2. Setting ASCII mode: Having successfully logged in, you will then be greeted by the friendly ftp> prompt. Since you will be sending up source code, which is plain text, the first thing you will type is ascii to put the ftp program into text mode.
3. Getting into the right directory: Next, get into the propper directory for the class. You do this by typing 'cd public_html' --This is just like the step in the telnet instructions.
4. Let the uploading begin! Once you're in the right directory, you will type: put localfile where localfile is the name of the file on your local machine. You will need to wait just a moment while it uploads the file, and then you will be told that it is finished and presented with another ftp> prompt.
5. Logout: Once you're done, type bye to disconnect and leave.

If you're interested in finding out more about ftp, you can type help at the ftp> prompt for a listing of common commands. A really handy one is ls which will show you a listing of files. This is useful for checking to see that your file actually uploaded properly.

You might be interested in using some neat-o GUI app for doing uploads like CuteFTP or some such. If so, I hope you can read help files, 'cuz you're on your own as far as I'm concerned.

FTP Example:

The following is a real-world example of an FTP session in action:

[mwhitley@listserv mwhitley]$ ftp 144.35.6.10    
Connected to 144.35.6.10.
220 zonker.cs.slcc.edu FTP server (Version wu-2.4.2-academ[BETA-15](1) Sat Nov 1 03:08:32 EST 1997) ready.
Name (144.35.6.10:mwhitley): markw
331 Password required for markw.
Password:
230 User markw logged in.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> ascii
200 Type set to A.
ftp> put report.html
local: report.html remote: report.html
200 PORT command successful.
150 Opening ASCII mode data connection for report.html.
226 Transfer complete.
5681 bytes sent in 0.0172 secs (3.2e+02 Kbytes/sec)
ftp> bye
221 Goodbye.
[mwhitley@listserv mwhitley]$

Note that the 'Transfer complete' line that showed up at the end of the transfer. This means it worked.

A Buffet of Editors

At some point you may want to edit files up on the server. The Zonker server has a variety of text editors to chose from. The list is currently:

• Emacs - A very nice text editor with available help.
• Pico - If you have used Pine before, this will be familiar to you.
• Vi - Real men use Vi.

Many of these editors have on-line help (including Vi--press F1, you'll see!). I can offer some modest help and I would like to politely ask that the more knowledgeable students please help those who are less knowledgeable.

If you have a favorite text editor that isn't on there, I can probably install it for you to use. Send me an email or something and I'll look into getting it installed. Also, to the best of my understanding, you can run X apps remotely from Zonker onto the client machines in the lab, so you don't have to do everything through a telnet session. I will double-check the feasiblity of this.

Things You Shoud NOT Do on the Lab Machine

Do not give out your login name and password to anyone. Do not use the school machine to launch denial-of-service attacks (or any other kind of attacks) against a remote system. Do not upload unauthorized copies of commercial software onto the system with the intent of distributing it to your friends. If you find any security holes in the lab machine, kindly tell me about them and I will patch them. In short, use your common sense, and don't act like an idiot.

Any Questions?

If you have any questions as to how any of this stuff should work, ask the lab aide, ask a fellow student, or ask me. Whatever you do, don't remain silent; you need to know how to use the lab.

Changelog

1/19/98 - Added news about being able to meet in the new science building, the news about Zonker being in DNS, and updated password info.