Files
ansible-playbooks/roles/fail2ban/README.md
T
Clément Désiles 6355a9aae5 fix(fail2ban): ban via ufw deny (DROP) instead of reject
REJECT needs the nft_reject kernel extension, which is unavailable on
this Arch kernel (iptables-nft reports 'Extension REJECT revision 0
not supported'), so every ban silently failed. DROP works everywhere
and is quieter toward attackers.
2026-09-05 16:45:12 +02:00

867 B

Fail2ban

Bans brute-force sources via UFW. Reads logs from the systemd journal (backend = systemd), so it works on both Arch and Debian.

Jails

  • sshd
  • nginx-http-auth

Notes

  • Logs to the journal (logtarget = STDOUT in fail2ban.local) — see journalctl -u fail2ban.
  • The systemd unit is hardened (ProtectSystem=full); the drop-in lives at /etc/systemd/system/fail2ban.service.d/override.conf and is fully managed by the role.
  • Firewall/banaction is UFW on every host; jails ban via ufw prepend deny (DROP — no kernel REJECT extension needed, and it doesn't reveal the host to attackers).

Variables

See defaults/main.yml.

Verify

sudo fail2ban-client status
sudo fail2ban-client set sshd banip 192.0.2.1 && sudo ufw status | grep 192.0.2.1
sudo fail2ban-client set sshd unbanip 192.0.2.1