Whenever you log into CLAIX (currently restricted to the login node `login18-4`) for the first time in a certain time period – currently several hours – you will be asked to enter _all_ types of identification, i.e., Username/Password, SSH key (if applicable), and Second Factor of choice. After this first login, further logins differ depending on whether or not you have SSH-authentication enabled.
**Note:** If you are using the `login18-4` node on the cluster, you are _required_ to have an active Second Factor token.
# Using Username/Password
If you have not [associated an SSH public key with your HPC account](adding an SSH key to your HPC account) or do not have the corresponding private key file on the computer from which you are accessing the HPC servers, all further logins are the same as the first one: you are required to enter both your Unix password (which you can [change in the RegApp](setting the service password)) and your Second Factor of choice (which you can [manage in the RegApp](adding 2FA tokens to your account)) every time you open a new session.