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Sergey G. Brester edited this page 2026-04-07 15:44:43 +02:00

Table of Contents

• Fail2ban · Welcome to the fail2ban wiki!
• Getting started
• HowTo's
• FAQ
• Banning
• Configuration
• UI, Controlling, Agents
• Miscellaneous
• Fail2ban in PHP (powered by Viktor Szépe):
• Fail2ban on OpenWRT:
• Troubleshooting Regex
• Sharing Fail2ban IP lists over the Internet with vallumd

Fail2ban · Welcome to the fail2ban wiki!

Getting started

• How fail2ban works
• Developers documentation
• Best practice

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HowTo's

• Install fail2ban on your Linux distribution
• Install or upgrade fail2ban manually
• Test newer fail2ban version
• Create standalone instance
• Ban something other as host/IP, like user or e-mail
• Fail2Ban and Docker

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FAQ

• Banning

  • Fail2ban does not detect some authentication failures or ban doesn't occur
  • Ban takes place but does not work, the intruder is still able to connect and continues an attack
  • Fail2ban detects resp. incorrectly blocks some authentication attempts as failure (e. g. bans my IP address)
  • Fail2ban does not ban and logs include iptables v...: unknown option "-w"
  • After Fail2ban starts, I'm not seeing the filter chains I expect as per my configuration

• Configuration

  • Proper fail2ban configuration
  • Fail2ban Troubleshooting
  • How fail2ban substitution resp. runtime interpolation works

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UI, Controlling, Agents

• Fail2ban Web Control
• Fail2ban UI

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Miscellaneous

• Fail2ban in PHP (powered by Viktor Szépe):

  • Ban IP addresses on shared hosting where Fail2ban is not available

• Fail2ban on OpenWRT:

  • https://github.com/peci1/fail2ban_openwrt

• Troubleshooting Regex

  • Developing and Troubleshooting Regex in Fail2ban

• Sharing Fail2ban IP lists over the Internet with vallumd

  • https://codeberg.org/stintel/vallumd

Best practice
How fail2ban works

HowTo's

• Manually install or upgrade
• Test newer fail2ban version
• Create standalone instance
• Ban something other as host/IP, like user or e-mail
• Simple Troubleshooting of Regex

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FAQ

• Configuration

  • No failure or no ban detection
  • Proper fail2ban configuration
  • Fail2ban Troubleshooting
  • How fail2ban substitution resp. runtime interpolation works