Frequently Asked Questions

Questions about logging in

I can't log in. Are the systems down?

If you're unable to log on to an NCCS system, first check the system status page. The status page will show any known system outages, planned downtimes, and regular maintenance windows. If none of these apply to you, contact NCCS User Services for assistance.

I tried three times to log in, and then I got a "Permission denied (publickey, keyboard-interactive)" message. What's going on?

As a security measure, some NCCS systems lock out userids after three consecutive failed attempts to log in. If you are locked out, you must call User Services at 301-286-9120 to have your userid unlocked.

How do I change my login shell?

To change your login shell on halem, charney, or palm, issue the following command:

chsh

You will be prompted for the path of the new shell, e.g., /bin/bash, /bin/csh, /bin/tcsh.

For all other HPC systems, you must e-mail NCCS User Services and request the change.

Questions about terminology

What is a PIN?

"PIN" stands for personal identification number, a four-digit number that is assigned to you by NCCS User Services along with your userid. You use your PIN in combination with the tokencode on your authentication key token (AKT) to login to NCCS systems.

What is a tokencode?

A tokencode is the sequence of numbers on your AKT. Tokencodes change every 30 - 60 seconds.

What is a passcode?

A passcode is a combination of two sequences of numbers that you use to log in to an NCCS system. The first sequence is your four-digit NCCS PIN, which is a permanent number assigned to you by NCCS User Services. The second sequence is your AKT tokencode, which changes every 30 - 60 seconds. Together these two sequences of numbers form a one-time-use passcode.

To enter your passcode, type your PIN and and tokencode as one sequence, without spaces.

Other questions

I forgot my password. How do I recover it?

If you forget your password, you must call NCCS User Services at 301-286-9120 to have it reset. For security reasons, we will not e-mail passwords.

When you call User Services to ask that your password be reset, we will ask you for your personal identification number (PIN) and the serial number on the back of your AKT. If you do not have these numbers, we will ask for your NCCS Identification Code: the secret word, phrase, or other identifier you specified when you applied for your userid. These are security measures to ensure that we are actually talking to you and not someone pretending to be you.

Note that User Services will NEVER ask you for your system password(s)---and you should never volunteer your passwords under any circumstances.

How do I change my password on Sourcemotel?

To change your password, first log on to sourcemotel.gsfc.nasa.gov using your existing password. Click on "My Page," then on "Account Maintenance," and then on the "change password" link.

How do I bring up an xterm window on the HPC systems?

The method for bringing up an xterm window is slightly different for each major operating system from which you're accessing an HPC system.

On a Windows OS, start your x-server (e.g., Exceed), open your ssh client (e.g., PuTTY), and enable x11 forwarding in the settings.

On a Linux OS, ssh using the -X option.

On a Macintosh OS, open the X11 application and ssh using the -X option.

How do I generate a public ssh key on my system?

To generate a public key, run the command-line program ssh-keygen (you can use either protocol 1 or 2). The public key will be placed at ~/.ssh/identity.pub (protocol 1) and ~/.ssh/id_dsa.pub or ~/.ssh/id_rsa.pub (protocol 2).

How do I set up a passwordless CVS environment on Sourcemotel?

1. Generate ssh keys on the system from which you are connecting.

2. Log into sourcemotel.gsfc.nasa.gov and click on "My Page," then on "Account Maintenance," and then on "Edit Keys."

3. Copy and paste the ssh keys you generated into the space provided and save.

I want to run a batch job, but I don't know what to enter for the -A option in PBS or the -P option in LSF. What should I do?

The -A option in PBS and the -P option in LSF require you to enter your Sponsor Code Account (SCA). To see a list of the SCAs on which you are authorized for a particular HPC system, execute the command getsponsor.

What are the Rules of Behavior for using NCCS computing resources?

The Rules of Behavior for using NCCS computing resources are documented here.