Background
On a newly installed Virtualmin server you might see events complaining about a missing config file for filter.d/sshd-ddos as per below:
Jul 13 19:57:35 host.com systemd[1]: Starting Fail2Ban Service... Jul 13 19:57:35 host.com systemd[1]: Started Fail2Ban Service. Jul 13 19:57:35 host.com fail2ban-server[31673]: Found no accessible config files for 'filter.d/sshd-ddos' under /etc/fail2ban Jul 13 19:57:35 host.com fail2ban-server[31673]: Unable to read the filter 'sshd-ddos' Jul 13 19:57:35 host.com fail2ban-server[31673]: Errors in jail 'ssh-ddos'. Skipping...
If you cd /etc/fail2ban/filter.d you will find that the file is simply missing.
Copy it from here: