What is fail2ban used for?

fail2ban is a Python daemon that reads log files and temporarily bans IP addresses with too many failed login attempts by updating firewall rules. It is a good fit for blocking SSH brute-force attempts, protecting web and mail servers from abuse, and adding a lightweight intrusion-prevention layer.

Is fail2ban open source?

Yes. fail2ban is open source under a custom licence. Its source code is on GitHub at fail2ban/fail2ban and is written mainly in Python.

Yes. fail2ban is open source, so the software itself is free to use under the terms of its own licence.

Can I self-host fail2ban?

Yes. fail2ban can be self-hosted on your own server or infrastructure; there is no official hosted version.

What are some alternatives to fail2ban?

Similar open-source tools in the Security category include step-ca, DefectDojo and OPNsense. SaaS products in the same category include Check Point, Fortinet and Palo Alto Networks.

Is fail2ban actively maintained?

Yes. The most recent commit to fail2ban was on 28 September 2026, and the latest release is 1.1.1, published on 15 August 2026. The project has 19k stars on GitHub.

fail2ban: open-source security

About fail2ban

Fail2Ban is an intrusion prevention daemon that watches log files, such as the authentication log, for repeated failed login attempts. When an address crosses a configured threshold, it adds firewall rules to reject new connections from that IP for a set period, which reduces brute-force noise against services.

It works out of the box with many standard logs, including those of sshd and Apache, and can be configured to read any log file for any error pattern you choose. IPv6 address matching has been supported since version 0.10. The README is frank about the limits: banning reduces the rate of failed attempts but cannot remove the risk of weak authentication, so you should still use two-factor or key-based authentication for important services.

Fail2Ban is written in Python and runs on Linux, macOS and BSD systems. Its license is listed as 'Other' on GitHub, and topics mention GPLv2, so confirm the terms. Documentation includes a manpage, wiki and developer guides. It is a long-standing, lightweight tool on self-managed servers, favored by sysadmins protecting SSH, web and mail services.

Key features

Scans logs for repeated failed logins
Bans offending IPs through firewall rules
Ready-made filters for sshd and Apache
Configurable ban durations and patterns
IPv6 address support
Works with any log file you point it at

Good fit for

→Blocking SSH brute-force attempts
→Protecting web and mail servers from abuse
→Adding a lightweight intrusion-prevention layer

Built with: Python
Tags: security; intrusion-prevention; firewall; linux; python; ssh; brute-force; log-monitoring; sysadmin

fail2ban: questions and answers

What is fail2ban used for?: fail2ban is a Python daemon that reads log files and temporarily bans IP addresses with too many failed login attempts by updating firewall rules. It is a good fit for blocking SSH brute-force attempts, protecting web and mail servers from abuse, and adding a lightweight intrusion-prevention layer.
Is fail2ban open source?: Yes. fail2ban is open source under a custom licence. Its source code is on GitHub at fail2ban/fail2ban and is written mainly in Python.
Is fail2ban free?: Yes. fail2ban is open source, so the software itself is free to use under the terms of its own licence.
Can I self-host fail2ban?: Yes. fail2ban can be self-hosted on your own server or infrastructure; there is no official hosted version.
What are some alternatives to fail2ban?: Similar open-source tools in the Security category include step-ca, DefectDojo and OPNsense. SaaS products in the same category include Check Point, Fortinet and Palo Alto Networks.
Is fail2ban actively maintained?: Yes. The most recent commit to fail2ban was on 28 September 2026, and the latest release is 1.1.1, published on 15 August 2026. The project has 19k stars on GitHub.