Shell instructions as follows:

Prerequisite on Debian bookworm:
sudo apt install rsyslog

Installation:
git clone https://github.com/fail2ban/fail2ban.git
cd fail2ban
sudo python setup.py install
sudo cp files/debian-initd /etc/init.d/fail2ban

sudo update-rc.d fail2ban defaults

sudo service fail2ban startsudo fail2ban-client status
sudo fail2ban-client version
sudo fail2ban-client --test
sudo fail2ban-client -h
Basic config Setup:
sudo nano /etc/fail2ban/jail.d/defaults-debian.conf
[sshd]

enabled = true