Connecting with SSH

SSH (the Secure SHell) is the standard way to open a remote shell session on a Linux server.

Connecting

The basic usage is straightforward: in your terminal on your local system, run the ssh command with the name of the system you want to use:

$ ssh tux.cs.drexel.edu
===============================================================================

                                Welcome to Tux!
              For technical issues, please e-mail ihelp@drexel.edu
                For help with classwork, please contact your TA.

===============================================================================

Last login: Tue Oct 14 13:58:13 2025 from 10.248.124.124
Uptime:  13:00:39 up 33 days, 6 min,  3 users,  load average: 4.80, 4.71, 4.67
mde48@tux$

If your username on the remote machine is different from your local username, specify the username with -l or with user@host:

$ ssh mde48@tux.cs.drexel.edu

See tmux for information on disconnecting from ongoing sessions and reconnecting to them.

Configuration

The SSH client configuration file in ~/.ssh/config allows you to set various settings so you don’t need to repeat them every time you run ssh. For example, if your laptop’s username is different from your Drexel username, you can put this in that file to automatically use the correct username:

# use my Drexel username to access Drexel systems
Host *.drexel.edu
    User mde48

Alternate Ports

It is rare, but you may occasionally encounter a system that runs SSH on a different port than its default of 22. On such systems, you can use the -p option to the ssh command to specify the port:

$ ssh -p 2022 some.weird.host