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Athena: Learning Tricks of the Trade

By Dana Levine

NEWS EDITOR

Project Athena, created in 1983 as a way to integrate computers into the undergraduate experience, consists of several hundred networked servers, workstations, and printers which are distributed across MIT's campus. Using this system can be quite intimidating to new MIT students, especially those who are unfamiliar with cryptic Unix commands, not to mention slashes which point the wrong way. What follows, therefore, is a brief introduction to some of the tricks you may find useful in your years at MIT.

Logging in remotely

While logging on to Athena can most easily be accomplished by going to any workstation on campus and logging on, it isn't always practical to do this, especially if you live across the river. Take heart: there are ways of logging in from the comfort of your own computer.

The most direct solution is to use a telnet type program, which gives you a text connection to your Athena account. Although you can accomplish this by typing telnet athena.dialup.mit.edu from a Windows command prompt, this will open up an unencrypted connection and will expose your password to anyone who knows a bit about hacking.

The preferred solution is to use a terminal program which protects your password with Kerberos encryption, preventing an enterprising hacker from using your account to infiltrate the Pentagon. Some programs which you can use are listed at http://web.mit.edu/acs/FAQ/ remote_access/ssh.html.

For those of you who are a bit more technically oriented, there are several ways to transform your personal computer into an Athena workstation. Groups at MIT have tailored distributions of Redhat Linux and NetBSD to run the Athena system. More information on this can be found at http://web.mit.edu/linux/ www/FAQ/ or http://web.mit.edu/ netbsd/doc/www/.

E-mail tricks

According to Information Services, the most frequently asked question for the past few weeks has been “How do I unforward my mail?”

The chpobox command can be used to forward e-mail to an account other than your Athena mailbox. Typing chpobox -s username@mit.edu fowards your e-mail. Typing chpobox -p will disable this mail forwarding. Be aware, however, that these changes will not take effect until the following midnight.

When you log on to Athena, the system will tell you how many messages you have waiting on the mail server. From here, you can use one of several different mail handlers, all of which are explained on the I/S web page and documentation.

While you are logged in, there are several ways to see if you have new e-mail waiting for you on the server. First of all, typing from will show you who has written the messages which are waiting for you on the server. If you insert this command into your .startup.tty file, the system will tell you at logon who has sent you each of the new messages waiting on the server.

It is possible to download messages to your account without removing them from the server. This would be useful if you use Eudora to read your e-mail but would like to check your mail while on campus at an Athena cluster. To do this, type inc -notrunc.

If you would like Athena to notify you of new messages as they come in, type zctl add mail pop. It is possible to receive the full header (subject, addressee, and sender) of each message, but this is a bit more complicated. There are detailed directions for doing this at http://web.mit.edu/answers/mail/mail_zephyr.html.

Locating people online

It is surprising how much information you can obtain about other students using Athena.

A commonly used tool for keeping track of people is the .anyone file, which contains the e-mail addresses of all of your friends. Typing znol will tell you who on the list is logged on and receiving zephyrs. If you don’t want to receive notification every time your friends log on, use znol off.

Many people prefer not to be bothered by zephyrs every minute or so (especially when they are trying to finish that problem set that was due an hour ago), so they type punt zwgc to disable the zephyr client and remove themselves from the zephyr notification server. However, some people prefer to not have their presence known to everyone, (remember that this section is about locating people). They can type zwgc hide.

While there is nothing that you can do to bother the former group of people (try e-mail), you can usually reach the latter. To find out if someone who doesn’t appear on your znol listing has hidden from you, try finger username. If your friend is logged on, the finger info should say “On since ...” and you should be able to successfully zephyr them.

If you know what Athena workstation or dialup server someone is logged into, finger username@machine will tell you how long they have been idle.

If one of your friends has logged off, you can tell when they logged off with add consult and then lastlog username. This actually records the changes to their home directory, so it may not be accurate if they uploaded files via ftp. If you know what dialup server they last logged into, logging into that dialup and typing last username will show you when they logged in and what computer they logged in from (the logs are flushed each day).

Logging out remotely

When you arrive home and realize that you have forgotten to log out of the last dialup you used, there is a simple way to log yourself out. First, log into that dialup, and then type ps -u username and then kill -9 x y z etc..., where the variables are the pid numbers listed. There is no simple way of remotely logging yourself out of an Athena workstation, although you can set this up with a bit of tinkering.

This guide is not intended to be a comprehensive tutorial. If you need to find something not listed here, feel free to consult http://web.mit.edu/is, which contains answers to just about every conceivable question and problem. Or feel free to ask around: that unassuming character sitting next to you in the Athena cluster may have written the piece of software that you are trying to use.