Setting up SSH access to ui.sci.unican.es

This guide explains how to generate a secure SSH key pair on your local computer and register it for access to ui.sci.unican.es.

1. Generate an SSH Key Pair

Open a terminal on your local machine and run:

cd $HOME
ssh-keygen -t ed25519 -f .ssh/id_ed25519-ui

When prompted:

Enter passphrase (empty for no passphrase): ********
  • Enter a strong passphrase (at least 8 characters, including letters, numbers, and symbols).
  • This passphrase protects your private key and will be required each time you use it.

You will see output similar to:

Generating public/private ed25519 key pair.
Your identification has been saved in /nfs/home/<group>/<username>/.ssh/id_ed25519-ui
Your public key has been saved in /nfs/home/<group>/<username>/.ssh/id_ed25519-ui.pub

2. Send Your Public Key to SCI Support

Instead of using ssh-copy-id, you must send your public key to SCI support so it can be installed on the server.

Display your public key with:

cat ~/.ssh/id_ed25519-ui.pub

Copy the entire output (it will start with ssh-ed25519 and end with your username/hostname).

Then send an email to: soporte.sci@unican.es

Iclude:

  • Your SCI username
  • A short request asking to install your SSH public key
  • The full contents of id_ed25519-ui.pub pasted in the email body

3. Connect Using Your SSH Key

To test the connection, use:

ssh -i .ssh/id_ed25519-ui <your_username>@ui.sci.unican.es

You should now be prompted for your SSH key passphrase, like this:

Enter passphrase for key '.ssh/id_ed25519-ui':

Enter the passphrase you set earlier.
If everything is correct, you will be logged into ui.sci.unican.es.

Summary

Step Command Description
1 ssh-keygen -t ed25519 -f .ssh/id_ed25519-ui Create a new key pair
2 cat ~/.ssh/id_ed25519-ui.pub Copy public key and send it to soporte.sci@unican.es
3 ssh -i .ssh/id_ed25519-ui <your_username>@ui.sci.unican.es Connect using your SSH key

Tips

  • Your keys are stored in ~/.ssh/:
  • Private key → id_ed25519-ui
  • Public key → id_ed25519-ui.pub
  • Never share your private key (id_ed25519-ui).
  • Use a password manager to store your SSH passphrase safely.
  • You can use ssh-add to cache your passphrase temporarily: bash ssh-add ~/.ssh/id_ed25519-ui