How To Install Fail2Ban on Debian 8

In this tutorial, we will show you how to install and configure Fail2Ban on Debian 8 server. For those of you who didn’t know, Fail2Ban is a utility that is used to detect and prevent brute force intrusion. By scanning logs for certain actions, such as repeated failed login attempts, Fail2Ban is able to alter firewall configurations to halt further events.

This article assumes you have at least basic knowledge of Linux, know how to use the shell, and most importantly, you host your site on your own VPS. The installation is quite simple and assumes you are running in the root account, if not you may need to add ‘sudo‘ to the commands to get root privileges. I will show you the step-by-step installation Fail2Ban on a Debian 8 (Jessie) server.

Prerequisites

• A server running one of the following operating systems: Debian 8 (Jessie).
• It’s recommended that you use a fresh OS install to prevent any potential issues.
• SSH access to the server (or just open Terminal if you’re on a desktop).
• A non-root sudo user or access to the root user. We recommend acting as a non-root sudo user, however, as you can harm your system if you’re not careful when acting as the root.

Install Fail2Ban on Debian 8

Step 1. Before we install any software, it’s important to make sure your system is up to date by running the following apt-get commands in the terminal:

apt-get update
apt-get upgrade

Step 2. Installing Fail2Ban.

Enter the following command to install Fail2Ban:

apt-get install fail2ban

Once that has finished, go ahead and create your “local” jail (this is where you define your overrides of jail.conf). You can read more about jails here:

cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local

Setup Fail2ban default configuration:

nano /etc/fail2ban/jail.local

Now, you will see the default section with some basic rules that are followed by fail2ban itself. If you want to add some extra layer of protection to your server, then you can customize each rule section as per your needs. There are few lines act as basic setup you can edit as necessary to suit your need including: ignoreip, bantime, findtime, and maxretry. You can read what each line means in the explanation available there.

[DEFAULT]

# "ignoreip" can be an IP address, a CIDR mask or a DNS host. Fail2ban will not
# ban a host which matches an address in this list. Several addresses can be
# defined using space separator.
ignoreip = 127.0.0.1/8

# "bantime" is the number of seconds that a host is banned.
bantime = 600

# A host is banned if it has generated "maxretry" during the last "findtime"
# seconds.
findtime = 600
maxretry = 3

# Destination email address used solely for the interpolations in
# jail.{conf,local} configuration files.
destemail = root@localhost

After making any changes to the Fail2Ban config, always be sure to restart Fail2Ban:

service fail2ban restart

With that done, you should now check your iptable rules for the newly added jail sections on each of the application modules you enabled:

iptables -L

Congratulations! You have successfully installed Fail2Ban. Thanks for using this tutorial for installing the Fail2Ban Debian 8 Jessie server. For additional help or useful information, we recommend you check the official Fail2Ban website.

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