Last Updated on March 4, 2026
reaction is a daemon that scans program outputs for repeated patterns, and takes action.
A common usage is to scan ssh and webserver logs, and to ban hosts that cause multiple authentication errors.
reaction does not have all the features of fail2ban, but it’s faster and has more manageable configuration.
Key Features
- Detect unsolicited, unwanted and virus-infected emails, calls, files, etc.
- Lightweight.
- Detect and resolve website performance issues proactively.
Website: framagit.org/ppom/reaction
Support:
Developer: ppom
License: GNU Affero General Public License v3.0
reaction is written in Go. Learn Go with our recommended free books and free tutorials.
Related Software
| Intrusion Prevention for SSH | |
|---|---|
| Fail2Ban | Intrusion prevention software framework written in Python |
| SSHGuard | Protects hosts from brute-force attacks against SSH and other services |
| denyhosts | Helps thwart SSH server attacks |
| iptables | Configure the Linux 2.4.x and later packet filtering ruleset |
| CSF | ConfigServer Security & Firewall |
| reaction | Daemon that scans program outputs for repeated patterns, and takes action |
Read our verdict in the software roundup.
 Explore our comprehensive directory of recommended free and open source software. Our carefully curated collection spans every major software category.This directory is part of our ongoing series of informative articles for Linux enthusiasts. It features hundreds of detailed reviews, along with open source alternatives to proprietary solutions from major corporations such as Google, Microsoft, Apple, Adobe, IBM, Cisco, Oracle, and Autodesk. You’ll also find interesting projects to try, hardware coverage, free programming books and tutorials, and much more. Discovered a useful open source Linux program that we haven’t covered yet? Let us know by completing this form. |