- on JURECA, enforce IPv4. For OpenSSH this can be done with the command line option `-4` or the configuration setting `AddressFamily inet`. In PuTTY the protocol can be overridden with the setting 'Internet protocol version' in the 'Connection' pane.
- Official manual, JURECA: https://apps.fz-juelich.de/jsc/hps/jureca/access.html#logging-in-to-system-name