💻 Quartz 4.0

self-taught
On Debian/Ubuntu:

sudo apt install fail2ban
 
# jail.local gets read after jail.conf, it is better to create it instead of modifying directly jail.conf
sudo cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local
sudo vim /etc/fail2ban/jail.local

[sshd]
 
enabled = true
port    = ssh
backend = systemd
maxretry = 2
findtime = 3600 # for 1 hour
bantime = 86400 # for 1 day
ignoreip = 127.0.0.1

sudo systemctl restart fail2ban

Monitoring

sudo fail2ban-client status sshd
sudo iptables -L -n

Unbanning

sudo fail2ban-client unban --all
 
sudo fail2ban-client unban <ip-address>