In Debian 12 fail2ban package contains very old /etc/fail2ban/filter.d/dropbear.conf
https://unix.stackexchange.com/questions/381066/fail2ban-not-picking-up-dropbear-auth-failures-again https://github.com/MichaIng/DietPi/issues/6665 https://github.com/fail2ban/fail2ban/issues/3791