Ubuntu

Sometimes fail2ban doesn’t start. This is usually because systemd is having a bad day.

First, connect to your server. (If you’re using a DigitalOcean Droplet their docs are here).

Then, make sure systemd knows fail2ban should be enabled:

root@example:~# systemctl enable fail2ban
Synchronizing state of fail2ban.service with SysV service script with /lib/systemd/systemd-sysv-install.
Executing: /lib/systemd/systemd-sysv-install enable fail2ban
Created symlink /etc/systemd/system/multi-user.target.wants/fail2ban.service → /lib/systemd/system/fail2ban.service.
root@example:~#

Next, check that the fail2ban configuration is OK:

root@example:~# fail2ban-client --test
OK: configuration test is successful
root@example:~#

Finally, start fail2ban and check it’s running:

root@example:~# systemctl start fail2ban
root@example:~# systemctl status fail2ban
● fail2ban.service - Fail2Ban Service
     Loaded: loaded (/lib/systemd/system/fail2ban.service; enabled; vendor preset: enabled)
     Active: active (running) since Tue 2023-05-30 17:04:59 UTC; 18s ago
       Docs: man:fail2ban(1)
   Main PID: 5471 (fail2ban-server)
      Tasks: 9 (limit: 1115)
     Memory: 12.0M
        CPU: 257ms
     CGroup: /system.slice/fail2ban.service
             └─5471 /usr/bin/python3 /usr/bin/fail2ban-server -xf start

May 30 17:04:59 example systemd[1]: Started Fail2Ban Service.
May 30 17:04:59 example fail2ban-server[5471]: Server ready
root@example:~#