What is SSH?

Secure Shell, or SSH, is a cryptographic (encrypted) network protocol to allow remote login, file transfer and other network services over a secure channel. SSH implementations typically provide scp and sftp commands to securely copy files from one host to another, and rsync supports transfers via SSH by default.

SSH replaces the less secure telnet, rlogin, rsh and rexec commands.

How do I use SSH?

To use SSH on Windows, you will need an SSH client (SecureCRT, Putty) or an environment that provides one (MobaXterm, Cygwin, Windows Subsystem for Linux).

The openSSH application is provided by default on MacOS and most Linux/UNIX distributions.

Configure your connection in your SSH application or open a terminal. In your terminal session, type this command (replacing username with the SEAS account name):

ssh username@eniac.seas.upenn.edu

The first time you connect to a host, you will be asked to verify its authenticity:

The authenticity of host 'eniac.seas.upenn.edu (2607:f470:8:64:5ea5::14)' can't be established.
ECDSA key fingerprint is 3a:ea:ab:7d:d1:65:21:7d:66:88:28:a4:c6:40:92:97 [MD5].
Are you sure you want to continue connecting (yes/no)?

Type yes and press the Enter key. That host will be remembered by its fingerprint from now on in the account on the machine you are currently using (including other machines that mount your home directory). The list of verified hosts is kept in ~/.ssh/known_hosts.

To complete your login, enter your password at the prompt (your PennKey password will work, as will your SEAS password if you have set one):

username@eniac.seas.upenn.edu's password:

Where username is the name of the account you are connecting to.

Two-Step Verification is required when using a PennKey password for SSH authentication on SEAS systems.

If you entered your PennKey password, you will be presented with a variation of this Duo two-factor prompt:

Duo two-factor login for xxxxx

Enter a passcode or select one of the following options:

1. Duo Push to phone_push (iOS)
2. Phone call to XXX-XXX-0123
3. SMS passcodes to XXX-XXX-0123 (next code starts with: 2)

Passcode or option (1-3):

Enter the number of the Duo option you would like to use and complete the challenge.

You will now begin a session on the remote computer using your default shell (typically bash), where you can type commands.

To end your session, type:


Ending your session this way will preserve your command history and perform other housekeeping tasks that might not occur if you simply close quit your terminal on your local computer, put it to sleep, or shut it down.

For additional information about the ssh command, please check the man page:

man ssh

Related Articles

© Computing and Educational Technology Services