You will need to use “ssh” (which stands for “secure shell”) client software to establish a login session with the CIS Unix systems. Under ssh, all data, including passwords, that passes over the network using the ssh protocol is encrypted, which negates the threat of a third party spying on the network traffic and reading your sensitive information.

The ssh protocol zealously insures that you're connecting to the precise host you specify; it uses a verification procedure involving each system's unique “host key”. So we recommend that you avoid specifying the cisunix.unh.edu hostname when using ssh; otherwise you may see confusing messages about conflicting host keys. The cisunix.unh.edu hostname is a "round robin" DNS record that (currently) picks either newton.unh.edu or fermat.unh.edu at random. So we recommend picking one of those hostnames for your session instead; it doesn't much matter which you pick. Use Fermat on even-numbered days, and Newton on odd-numbered days. Or vice-versa. Or flip a coin.

If you are using a computer with a Unix-like operating system (including Mac OS X and Linux), you can use the slogin command in a terminal window. You typically specify both the machine name and (as an option) the username on the command line. For example, use any of:

% slogin -l joe newton.unh.edu
% slogin -l joe fermat.unh.edu

If you have the same username on both systems, you can omit the option:

% slogin newton.unh.edu
% slogin fermat.unh.edu

Since the username is specified, slogin will skip past the login: prompt to the Password: prompt. (It's possible to avoid even the Password: prompt by cautious use of an ssh "agent" program that will provide access via secure (so-called) "key exchange"; use is beyond the scope of this document, but widely documented elsewhere.)

For Windows users: a good free client that allows ssh connections is PuTTY; instructions for retrieving and downloading are at http://www.chiark.greenend.org.uk/~sgtatham/putty/.

You will need to specify both your username and password to log in; if you haven't specified your username in an slogin command (as shown above), you'll be prompted for it; in either case, remember that the letters in your username are all-lowercase.

Note that your password is not displayed when you type it in. This is to keep it secret from anyone who might be looking over your shoulder. Remember that your password is also case-sensitive. Make sure you haven't unintentionally pressed the Caps Lock key, for example. Note also if you have a numeric keypad, its keys may not be sending what you think they are, depending on the Num Lock status.

If you make a mistake in typing your username, you'll need to start things over again.

If you make a mistake in typing in your password, the system will typically ask you to retry typing it. Please note that if you try logging into the system too many times with the wrong password, the intrusion detection system on Fermat and Newton will deny further connection attempts from your host for a certain period.

The default login interface for older users is a simple “menu” as shown in Figure 1, “CIS Unix Menu”

Figure 1. CIS Unix Menu

This menu interface allows one-digit selection of some of the most commonly used programs on the system: the alpine program for e-mail, and the lynx Internet browsing program. You can also access the normal command shell prompt, change your password, and log out. You're told whether you have mail in your INBOX, and information about your disk quota, and (as if you need reminding) what your e-mail address is.

If you want to switch to the shell interface temporarily, choice 3 will do it for you. To make your default interface the shell instead of the menu, type 7; this will take effect at your next login.

An alternate method to use the CIS Unix systems is by typing commands to the Unix shell. This is the default interface for new users. Many examples in this document and elsewhere assume that you can type commands to the Unix shell. When using the shell, you have full access to hundreds of Unix commands, instead of the few shown at the menu. So you might find it's worth knowing.

The normal Unix shell prompt is a percent sign:

% 

You can type Unix commands at this prompt, for example, to run the alpine program to read and compose mail:

% alpine

When one program ends, the shell prompt reappears, and you give your next command. And so on. When you're done, type the logout command:

% logout

If you want to use the menu interface temporarily, give the menu shell command:

% menu

To make the menu interface the default when you log in, the command is menuon:

% menuon