Logging into pangea with Samson

Last revision July 19, 2004

The simplest way to run commands on pangea is by logging in from a remote computer to create a command line session that runs the normal Unix shell program to process your commands.

You should use a remote login program that encrypts your password before sending it over the network, so that it cannot be captured by a hacker. Your basic choices are a kerberized telnet program, which uses your SUNet ID name and password to authenticate you, or an ssh program, which uses your local pangea account name (should be identical to your SUNet ID name) and your local pangea password (which should be different from your SUNet ID password).

Stanford has developed its own version of a "telnet" program for network command line login to Unix systems from Macintosh and Windows PCs, called Samson, available on the Essential Stanford Software web site. This program works in conjunction with the PCLeland or MacLeland kerberos authentication agents to provide encrypted login connections.

On the Dell computers in the Mitchell A65 cluster, after you login to Windows and get the Windows desktop, you should see the Samson icon:

Click it to start. Or you can use the Start menu on the lower left and find Samson under the Programs header.

If you get an error during startup of Samson, such as "can't get IP address", please report that to the cluster manager.

Samson will open the Connect window. From here you can specify which computer you want to connect to. There may be predefined "sessions" listed in the upper left. If one of those is the computer you want, just double-click it. Otherwise, type in the IP name of the computer you want in the Host: field and click on the Connect button. (Screenshots are Mac OS X, however, Samson for Windows utilizes a similar interface.)

If you get a "Host name not found" message when Samson tries to connect to the remote computer, check the spelling that you used; if it was correct, this could be a symptom of a network problem that should be reported to the School's network manager.

Samson opens a connection to the remote computer and and will pop up a dialog box to request your SUNet ID and password. Enter your SUNet ID and password and click the OK button.

You will go directly to a command login shell with no further prompts from the remote computer. This login session will be fully encrypted.

If the remote computer does not support kerberized logins, or you do not have the PCLeland or MacLeland kerberos program on your computer, Samson will revert to the plain-text (unencrypted) telnet protocol. If you continue to login in this case, remember that your password will be sent across the network in a plain-text format that is vulnerable to being captured by hackers. Type your pangea account name after the login: prompt and press the RETURN key. Case is important. Use lowercase. Do not add extra spaces at the end of your name.

You will then get a password: prompt. Type your local pangea password exactly, with no extra spaces at the end, and press the RETURN key. Do not use your SUNet password.

If you get the message "login incorrect", you have probably mistyped something. Try again.

When fully logged in, the Unix shell program will print a "prompt" to the screen to show that it is ready to accept commands. You should see
      pangea>
You can type a Unix command now, pressing the RETURN key at the end of the command to make it run. When that command finishes running, a new prompt will be printed to the screen.

To logout from a Unix system, type the command logout and press the RETURN key. Generally, this is the only command that will log you out (exit will usually work as well). Other possible commands such as logoff, quit, or bye are not accepted.

You must logout when you are done working! Otherwise, someone else could sit down at your terminal and "become" you with access to all your files!

WARNING: if you are using PCLeland or MacLeland on a public computer, you must also select Logout from the PCLeland or MacLeland menu, or shutdown the computer. Otherwise, PCLeland or MacLeland may keep your kerberos authorization credential active on that computer, potentially for several hours, depending upon how the computer has been configured. During that time, anyone else could sit down at this computer and login to campus computers and services (such as Axess) using your account.

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