Shellx is under a botnet based brute force password guessing attack.  The attackers seem to be under the mistaken belief that it is a D-link router as they are primarily trying passwords for a non-existent user D-link.

To limit the resources consumed, I’ve set the fail2ban time to an hour instead of the usual ten minutes so if you get your password wrong three times you will either need to wait an hour or use a different shell server.