Tools

Free fail2ban tools

Test filters, write configs and read logs without touching your server. Every tool runs entirely in your browser — nothing you paste is uploaded.

Updated Checked against fail2ban 1.1.1
fail2ban regex testerpaste log lines, choose any of the 96 built-in filters or your own failregex, and see what matches and which IPs would be bannedFilter generatorclick the IP in one log line and get a complete filter.d file, a jail and the test commandjail.local generatorpick distro, firewall and services; copy a clean, commented jail.localLog analyzerfind attacking IPs, failures per hour and usernames tried in auth.log or web logsBantime calculatorconvert 1d12h, 1w or 1mo to seconds and simulate incremental bansCommand builderthe exact fail2ban-client command to unban, ban, whitelist or check status

Which tool do I need?#

You want to… Use
Check whether a filter catches your log lines Regex tester
Protect an app fail2ban has no filter for Filter generator, then the regex tester
Set up fail2ban on a new server jail.local generator
See who is attacking you and what fail2ban would ban Log analyzer
Pick bantime, findtime and incremental settings Bantime calculator
Unban someone right now Command builder or unban an IP

How the tools work#

The regex tester, filter generator and log analyzer share one engine: a JavaScript port of the parts of fail2ban that decide whether a line is a failure — date detection with fail2ban's own date templates, prefregex, failregex, ignoreregex, the <HOST> and <F-…> tags and multi-line failure IDs. The built-in filters are extracted from fail2ban 1.1.1 and translated from the exact regexes fail2ban compiles. We check the engine against fail2ban's own results on the 1,028 sample log lines in fail2ban's test suite; it agrees on 99.7% of them.

The tools are a fast way to iterate. Before you rely on a filter in production, confirm it on the server with fail2ban-regex.

FAQ#

Is it safe to paste server logs into these tools?#

Yes. The pages download the filter definitions once and do all processing in your browser; no log content is sent to any server. You can even disconnect from the network after the page loads.

fail2ban regex testerFree online fail2ban regex tester. Paste log lines, pick any built-in filter or write a failregex with <HOST>, and see matches, missed lines and IPs to ban.jail.local generatorFree fail2ban jail.local generator. Pick your distro, firewall and services, set bantime, findtime, maxretry and ignoreip, and copy a clean, commented config.Log analyzerPaste auth.log, secure, journalctl or nginx/Apache logs and see attacking IPs, failures per hour, usernames tried and which IPs fail2ban would ban. Runs locally.

Spotted something wrong or out of date? Tell us — every page is checked against the current fail2ban release.