To protect against mass attacks I used to setup a recidive jail that checked the fail2ban log.
Nowadays fail2ban has a built in solution against mass attacks: bantime.increment, bantime.factor, etc. The more failed tries the longer the ban. It allows a few more attempts for normal users while killing bots that try much more through exponential growing ban times.
I can add these manually in the fail2ban.local, but it would be nice if:
a) They are configurable in Webmin (default and per jail)
bantime.increment
bantime.factor
bantime.maxtime
bantime.overalljails
bantime.rndtime
b) Switched on by default to have a more hardened setup out of the box for those who do not dive directly in the settings.