Fail2ban is a security tool that monitors system logs for signs of an automated attack on your Linode and blocks the IP address of the attacker using iptables.
It can also send alerts via email. It is primarily used to protect against SSH attacks but can be configured to protect other services that use log files and are at risk of compromise.
Installing and Configuring Fail2Ban on a Linux Server
To install Fail2Ban, first, let's run a quick system update.
sudo apt-get update && apt-get upgrade -y
Then install Fail2Ban:
sudo apt-get install fail2ban
How to Configure Fail2Ban
Fail2Ban's default configurations will be sufficient for our purposes, but if you'd like to tweak its settings, you can refer to Linode's Guide on Using Fail2ban to Secure Your Server.
Once you're done, we'll further configure a firewall to protect our server in our next lesson.