@@ -9,3 +9,5 @@ If you have not [associated an SSH public key with your HPC account](adding an S
# Using SSH key-pairs
If you have [associated an SSH public key with your HPC account](adding an SSH key to your HPC account) and have at least one corresponding private key file on the system used to access the HPC cluster, all further logins within this certain time period will _only_ require SSH-authentication. In the case that you are running an `ssh-agent` in the background to manage your private key password, you will be directly authenticated, otherwise, you will be prompted for the password of your private key file when opening a new session.
**Note:** Access to the cluster requires password and second factor on first connection within a certain time frame. If you use an ssh config file (a file in your `.ssh` folder named `config`; for more info query your preferred search engine or start [here](https://linuxhandbook.com/ssh-config-file/)), make sure that for this domain (e.g., `*.hpc.itc.rwth-aachen.de`) you are **not** using the public key as your preferred authentication method (i.e., do **not** set `PreferredAuthentications publickey` for this domain). Doing so will prevent the password request and thus login.