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What is SSH?

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4.0 - Updated on 06/24/2021 by Denman, Jon

3.0 - Updated on 05/20/2020 by Denman, Jon

2.0 - Updated on 08/22/2019 by Denman, Jon

1.0 - Authored on 09/21/2017 by Frederick, Jon

This page is intended for those who are not familiar with ssh.

What is this "ssh" thing?

At it's most basic, ssh is a method to connect securely from a local computer to a command-line session on a remote computer. It is the method by which our Khoury Linux machines are available for remote use. Connecting to a Khoury machine via ssh is the first step in signing up for a Khoury account. ssh is capable of more than we outline above (it's a pretty hand tool), but that's it in a nutshell.

What is my username for ssh?

For Khoury machines such as the login server login.khoury.northeastern.edu, your username is the same as your Khoury (https://my.khoury.northeastern.edu/) username.

To avoid being blocked by our automated SSH brute force protection tool, please make sure of the following: 

  1. The username that you are connecting with is all lowercase .  Even if you signed up with a capital letter username, our system makes it all lowercase.  Connecting with an upper-cased username is the same as using an invalid one.

  2. You are connecting to login.khoury.northeastern.edu or login-students.khoury.northeastern.edu.  Any other server (such as khoury.northeastern.edu) will not work.

  3. Please make sure you can log into https://my.khoury.northeastern.edu before attempting to SSH into our resources or file a ticket with us.

  4. If you are blocked, the message you will receive is Connection Refused.  Please refer to our article on automatic SSH blocking below for more information on this.

So how do I use ssh?

In order to connect to a remote server via ssh, you'll need what's called an "ssh client." Just as your web browser (eg: Chrome, Firefox, Internet Explorer, Safari, etc...) is your means of browsing the web, an ssh client is your means of connecting to a remote ssh server like the ones we run here at Khoury. But first, a note on security: If you follow the directions below, and start receiving errors of the form "server unexpectedly closed network connection," you might have fallen afoul of one of our security systems. If this happens: Don't worry! Just visit our page about automatic blocking of repeated failed ssh login attempts, and follow the directions you find there! That having been said, your options for an ssh client depend on your Operating System. If you are using:

Microsoft Windows

We recommend the excellent PuTTY, by Simon Tatham. PuTTY is free to download and use without charge. (It's also Free/Open Source software - if you don't know what that means, don't worry!) To download and use PuTTY, please refer to the link above. (You just want to download PuTTY (ie: putty.exe) for now. Later, feel free to explore any of PuTTY's add-on programs, such as PSCP, PSFTP, etc. Note that PuTTYtel (puttytel.exe) will not work to connect to Khoury Linux systems, as it only provides support for the older telnet protocol, a totally different thing from ssh.) Once you've got PuTTY up and running, simply:

  1. enter login.khoury.northeastern.edu in the "Host Name (or IP address)" field
  2. click the "Open" button
  3. A "PuTTY Security Alert" dialog should appear stating "The server's host key is not cached in the registry. You have no guarantee that the server is the computer you think it is..." (and so on). If you are the kind of person who really cares about security, you can learn how to verify a server's identity remotely. For now, just click "Yes" to add login.khoury.northeastern.edu's "ssh host key" to the list of ssh servers PuTTY knows about.
  4. A window should appear containing the prompt "login as: ”. Here you should enter the login name you are using: "account" if you are doing the Khoury Account signup process, or your Khoury account if you are connecting to one of our ssh servers after your account has been set up.
  5. In the same window, you should then receive the prompt "[Account you provided]@login.khoury.northeastern.edu's password: ”. Here you should enter the appropriate password: "account" if you are doing the Khoury Account signup process, or your Khoury password if you are connecting to one of our ssh servers after your account has been set up.
    Note: PuTTY does not display any characters on the screen when you type in your password, not even "*". This is an intentional security measure to keep someone who can see your screen from knowing how long your password is. A side effect, however, is that sometimes people think PuTTY isn't accepting their input. It is! Just type in your password (ignore the lack of response on the screen), and hit Enter!
  6. That's it! You should be in! When you're done, end your session by typing "exit" or "logout." (Note: That step doesn't apply to using ssh for the Khoury Account signup process.)

Mac OS X, Linux, BSD, and other UNIX variants

Most UNIX variants (don't worry if you don't know what that means), including Apple's Mac OS X, most Linux distributions, Free/Net/Open/Dragonfly/etc BSDs, commercial UNIXes like Solaris/AIX/etc, and so on already include a fully functional ssh client called, appropriately enough, "ssh”! To use this built-in ssh client:

  1. Open a Terminal. On Mac OS X, the Terminal is located in your Applications -> Utilities folder (Applications is the folder on your hard drive that contains Safari, Mail, etc). On newer versions of OS X, you can also go the route: Launchpad -> Utilities. The location of the terminal varies on other Linux and UNIX distributions.
  2. Once your Terminal is open, type the following at the prompt: ssh [Account You're Using]@[Server to which You're Connecting], then press Enter or Return on your keyboard. eg:
    • ssh [Your Khoury Login]@login.khoury.northeastern.edu if you are connecting to one of our ssh servers after your account has been set up
  3. You should receive output along the lines of "The authenticity of host 'login.ccs.neu.edu (129.10.117.100)' can't be established... Are you sure you want to continue connecting (yes/no)? " If you are the kind of person who really cares about security, you can learn how to verify the authenticity of a server's identity remotely. For now, just type "yes" to add login.khoury.northeastern.edu's "ssh host key" to the list of ssh servers ssh knows about.
  4. You should then receive a prompt for account@login.khoury.northeastern.edu's password: (or similar). Here you should enter the password for your Khoury account.
    Note: ssh does not display any characters on the screen when you type in your password, not even "*". This is an intentional security measure to keep someone who can see your screen from knowing how long your password is. A side effect, however, is that sometimes people think ssh isn't accepting their input. It is! Just type in your password (ignore the lack of response on the screen), and hit Enter/Return!
  5. That's it! You should be in! When you're done, end your session by typing "exit" or "logout." (Note: That step doesn't apply to using ssh for the Khoury Account signup process.)