See also Computer Systems at IMADA.

Passwordless SSH Connections

To connect to a server through SSH you either need to type your password each time, or set up a public/private key pair. You can read more about public/private keys at https://help.ubuntu.com/community/SSH/OpenSSH/Keys, and a short version below.

On each machine from where you want to log in, do the following once:

1. If you do not already have a keypair (check ls .ssh/id_rsa*, if you see .ssh/id_rsa and .ssh/id_rsa.pub then you have one), run ssh-keygen and follow instructions (for security you should add a passphrase so someone copying your private key can not just use it). Note, you should not copy your private key (.ssh/id_rsa) anywhere. Create a new key-pair on each machine.

2. Run ssh-copy-id yourUsername@the.server.sdu.dk.

   Attention

   If you do this step manually, without ssh-copy-id, be careful the permisions on the remote .ssh/ folder, and its contained files, are correct (only “user” permissions are allowed).

3. Try ssh yourUsername@the.server.sdu.dk. You should now be able to log in without typing your password.