Configure Fail2ban on a Linux VPS - Documentation Infrawire

Fail2ban watches service logs and temporarily bans IPs that behave abusively (repeated SSH failures, HTTP probing, etc.). It complements UFW and SSH hardening.

Prerequisites

Ubuntu/Debian (or derivative) with sudo
The service to protect already running (e.g. sshd, nginx)

Installation


Bash
sudo apt update && sudo apt install -y fail2ban
sudo systemctl enable fail2ban
sudo systemctl start fail2ban

Basic configuration

Place custom files under /etc/fail2ban/jail.d/ so updates do not overwrite them.

Create /etc/fail2ban/jail.d/local.conf:


INI
1[DEFAULT]
2bantime  = 1h
3findtime = 10m
4maxretry = 5
5ignoreip = 127.0.0.1/8 ::1
6
7[sshd]
8enabled = true
9port    = ssh
10logpath = %(sshd_log)s
11backend = %(sshd_backend)s

If you changed the SSH port, set port = 2222 (example) instead of ssh.

Reload Fail2ban:


Bash
sudo systemctl restart fail2ban
sudo fail2ban-client status
sudo fail2ban-client status sshd

Nginx (aggressive HTTP patterns)

Add for example:


INI
[nginx-http-auth]
enabled = true
port    = http,https
logpath = /var/log/nginx/error.log

Adjust log paths to your setup.

Best practices

Add your static IP to ignoreip while testing.
Check sudo fail2ban-client status sshd after deployment.
Bans are temporary (bantime); tune to your tolerance.

Unban an IP manually


Bash
sudo fail2ban-client set sshd unbanip 198.51.100.10

Troubleshooting

No bans: ensure enabled = true, correct logpath, and the service logs failures.
Locked out: use your provider’s console / IPMI or another IP, then fix ignoreip or unban.