man > fail2ban(1)

man perldoc info pydoc3 ri search

📛 NAME

fail2ban — a set of server and client programs to limit brute force authentication attempts.

🚀 Quick Reference

Use Case	Command	Description
🖥️ Start the server	fail2ban-server	Start the fail2ban server daemon
📊 Check status	fail2ban-client status	Get current status of all jails
🔒 Manually ban an IP	fail2ban-client set <jail> banip <ip>	Immediately ban an IP address in a specific jail
🔓 Manually unban an IP	fail2ban-client set <jail> unbanip <ip>	Remove a ban for an IP address
🧪 Test regex patterns	fail2ban-regex <log> <regex>	Test regular expressions against log files
🔄 Reload configuration	fail2ban-client reload	Reload configuration without restarting the server

📖 DESCRIPTION

Fail2Ban consists of a client, server and configuration files to limit brute force authentication attempts.

The server program fail2ban-server is responsible for monitoring log files and issuing ban/unban commands. It gets configured through a simple protocol by fail2ban-client, which can also read configuration files and issue corresponding configuration commands to the server.

For details on the configuration of fail2ban see the jail.conf(5) manual page. A jail (as specified in jail.conf) couples filters and actions definitions for any given list of files to get monitored.

For details on the command-line options of fail2ban-server see the fail2ban-server(1) manual page.

For details on the command-line options and commands for configuring the server via fail2ban-client see the fail2ban-client(1) manual page.

For testing regular expressions specified in a filter using the fail2ban-regex program may be of use and its manual page is fail2ban-regex(1).

⚠️ LIMITATION

Fail2Ban is able to reduce the rate of incorrect authentications attempts however it cannot eliminate the risk that weak authentication presents. Configure services to use only two factor or public/private authentication mechanisms if you really want to protect services.

A local user is able to inject messages into syslog and using a Fail2Ban jail that reads from syslog, they can effectively trigger a DoS attack against any IP. Know this risk and configure Fail2Ban/grant shell access accordingly.

📁 FILES

/etc/fail2ban/*

✍️ AUTHOR

Manual page written by Daniel Black and Yaroslav Halchenko

🐛 REPORTING BUGS

Report bugs to https://github.com/fail2ban/fail2ban/issues

©️ COPYRIGHT

Copyright © 2013

Copyright of modifications held by their respective authors. Licensed under the GNU General Public License v2 (GPL).

👀 SEE ALSO

fail2ban-server(1) fail2ban-client(1) fail2ban-regex(1) jail.conf(5)

📛 NAME 🚀 Quick Reference 📖 DESCRIPTION ⚠️ LIMITATION 📁 FILES ✍️ AUTHOR 🐛 REPORTING BUGS ©️ COPYRIGHT 👀 SEE ALSO