Fail2ban

What is Fail2ban?

Fail2Ban is a free, open-source software tool that protects servers from brute-force attacks and other types of malicious activity. It monitors log files for suspicious activity and blocks IP addresses that are trying to ac…


This content originally appeared on DEV Community and was authored by samnang rosady

What is Fail2ban?

Fail2Ban is a free, open-source software tool that protects servers from brute-force attacks and other types of malicious activity. It monitors log files for suspicious activity and blocks IP addresses that are trying to access a server.

Why use Fail2ban?

There are several reasons to use Fail2ban:

  • Prevents brute force attacks on services
  • Reduces server load from automated login attempts
  • Provides an extra layer of security beyond firewalls
  • Notify when there is an IP is ban/unban through SMTP, Webhook

How it works

Image description

  • Fail2Ban scans log files for suspicious activity, such as too many access, failed attempts through access or error files
  • Fail2Ban creates a firewall rule to block the IP address that is causing the suspicious activity
  • The IP address is blocked for a specified amount of time

Basic understanding Fail2ban

Jails:

  • Jails serve as rule sets that dictate the conditions under which an IP address should face a ban which defined by monitoring log files
  • Predefined jail configurations can be found in /etc/fail2ban/jail.conf within Fail2ban

Filters:

  • Filters are instrumental in scrutinizing service logs using regex patterns to identify potentially malicious activities, like intrusion attempts.
  • These filters are typically stored in /etc/fail2ban/filter.d/

Actions:

  • Actions encompass a range of responses, from IP address bans to notifications and the execution of custom scripts
  • Commands outlining ban or unban procedures for IP addresses are typically housed in /etc/fail2ban/action.d/

GitHub Sample Repository 🐳

Enjoy you practice 🌟


This content originally appeared on DEV Community and was authored by samnang rosady


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