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Practical OPNsense
Building Enterprise Firewalls with Open Source

by Markus Stubbig
This book is the ideal companion for understanding, installing and setting up an OPNsense firewall. Each chapter explains a real-world situation, describes the theoretical fundamentals, and presents a laboratory experiment for better understanding. Finally, it offers a solution using OPNsense methods and knowledge from a technical background. The chapters are mostly independent of each other, but presented with increasing levels of proficiency. Thus, the topics dealt with are appropriate for beginners to professionals.

Available as (FREE) E-Book

bundled with Deciso products & services

Deciso B.V. | OPNsense Webshop


OPNsense, a Deciso® Open Source Project

Can your Firewall do all this ?

✓ No license cost ✓ Free Download ✓ Best Open Source Firewall

OPNsense, the Open Source Firewall that is easy-to-use and protects your network.

Easy User Interface
Stateful Firewall
Traffic Shaper
Two-Factor Authentication ( 2FA )
Captive Portal
Virtual Private Network
High Availability CARP
Filtering Caching Proxy
Inline Intrusion Prevention
Multi-WAN Load Balancing
High Performance TCP/HTTP Load Balancer

Issue Let's Encrypt Certificates
Full Mesh VPN routing using Tinc
Backup to Google Drive
Support for Virtual Installs
Netflow Exporter
Network Flow Monitoring
Built-in Reporting & Analysis
Plugin Support
Community & Commercial Support
Online Searchable Documentation


Download and install in minutes, use the responsive modern GUI for easy setup. Community & Commercial support available.

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Easy build tools, join the development today! We believe sharing is the way to go; it’s your choice, BSD style license.

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Become a project partner, get listed on the partner page and use OPNsense® in your own products and offerings.

Partner benefits

Founded in Middelharnis, The Netherlands by Deciso B.V. in 2015 with a small team of highly skilled professionals and open source enthusiasts. OPNsense is a fast growing community project with thousands of active installations around the globe.
Our mission is to make OPNsense the most widely used open source security platform. We give users, developers and business a friendly, stable and transparent environment.
Fully Supported
The project offers online documentation, an active community forum and commercial support for businesses, resellers and integrators.

User Testimonials

Manuel Kasper Author of m0n0wall

"In my view, it is the perfect way to bring the m0n0wall idea into 2015, and I encourage all current m0n0wall users to check out OPNsense and contribute if they can."

Manuel Alexander Herzog OPNsense User

"Sophos UTM is good but to sofisticated for my needs. So I tried OPNsense and now EVERYTHING is as I want to have it. It is simple and with a great GUI."

Boris Hoppe CEO CompuNet Systems GmbH

"OPNsense provides more features, more reliability and more performance than any other commercial firewall product we had in use ever before. Being open source, we have full access regarding update plans and so on."