Remote Access via SSH (to the IMADA Computer Lab)

The “ssh” (Secure Shell) program makes it possible to make encrypted connections to other (Linux) computers. The basic usage is to get command line access on remote machines (for example in the IMADA Computer Lab), but it can do much more, like facilitating file transfers through the “scp” and “rsync” commands, and proxying network traffic through other computers.

• How Secure Shell Works (SSH), Computerphile on Youtube.

The basic command is:

ssh username@hostname

The IMADA Computer Lab machines are not accessible directly from the internet, so you will either need to be physically on SDU on the eduroam network, or enable the SDU VPN. Once on the right network, you can connect to one of the lab machines. They each have a name on the form “imadaX.stud-srv.sdu.dk” where “X” is a number between 0 and 3. For example:

ssh myUsername@imada3.stud-srv.sdu.dk

If you use the machines often, it can be bothersome to type this all the time, so we can make an SSH configuration file which simplifies it. If the folder “~/.ssh” does not exist, create it. Then create/open the file “~/.ssh/config”, and fill in something similar to the following:

Host imada0
    User myUsername
    HostName imada0.stud-srv.sdu.dk
Host imada1
    User myUsername
    HostName imada1.stud-srv.sdu.dk
Host imada2
    User myUsername
    HostName imada2.stud-srv.sdu.dk
Host imada3
    User myUsername
    HostName imada3.stud-srv.sdu.dk

To connect to machine 3 you can now use “ssh imada3”.

Further, by generating and copying keys, it is possible to avoid having to type your password, see Passwordless SSH Connections.

See IMADA Virtual Computer Lab for more information on the IMADA Computer Lab.