Fail2ban is a software that reads logs and bans IP addresses (IPv4 and IPv6) that abuse the system or perform actions that correspond to certain reasons for banning them.

https://fr.wikipedia.org/wiki/Fail2ban

I find it unfortunate that certain errors (http 400, for example) are not banned by default.

Here are my files:

jails

excerpt from /etc/fail2ban/jail.local (which is a copy of /etc/fail2ban/jail.conf) 

[nginx-3xx]
enabled = true
port    = http,https
logpath = /var/log/nginx/access.log
backend = polling
bantime = 30d



[nginx-4xx]
enabled = true
port    = http,https
logpath = /var/log/nginx/access.log
backend = polling
bantime = 30d


[nginx-400]
enabled = true
port    = http,https
logpath = /var/log/nginx/access.log
backend = polling
bantime = 30d
maxretry = 0

Filters

fichier complet pour /etc/fail2ban/filter.d/nginx-3xx.conf 

[Definition]
failregex = ^<HOST>.*"(GET|POST|HEAD).*" (301|302) .*$
ignoreregex =

complete file for /etc/fail2ban/filter.d/nginx-4xx.conf 

[Definition]
failregex = ^<HOST>.*"(GET|POST|HEAD).*" (404|444|403|405) .*$
ignoreregex =

complete file for /etc/fail2ban/filter.d/nginx-400.conf 

[Definition]
failregex = ^<HOST>.*".*" (400) .*$
ignoreregex =