Book Image

OPNsense Beginner to Professional

By : Julio Cesar Bueno de Camargo
5 (1)
Book Image

OPNsense Beginner to Professional

5 (1)
By: Julio Cesar Bueno de Camargo

Overview of this book

OPNsense is one of the most powerful open source firewalls and routing platforms available. With OPNsense, you can now protect networks using features that were only previously available to closed source commercial firewalls. This book is a practical guide to building a comprehensive network defense strategy using OPNsense. You’ll start with the basics, understanding how to install, configure, and protect network resources using native features and additional OPNsense plugins. Next, you’ll explore real-world examples to gain in-depth knowledge of firewalls and network defense. You’ll then focus on boosting your network defense, preventing cyber threats, and improving your knowledge of firewalling using this open source security platform. By the end of this OPNsense book, you’ll be able to install, configure, and manage the OPNsense firewall by making the most of its features.
Table of Contents (25 chapters)
1
Section 1: Initial Configuration
6
Section 2: Securing the Network
13
Section 3: Going beyond the Firewall

Useful system commands

As a Unix-like system, OPNsense has a lot of useful commands. In the following, we will explore some of these commands.

Let's dive into a practical scenario.

Assume that you lost access to the webGUI and want to find which process is using Transmission Control Protocol (TCP) port 443 on OPNsense. We can find running processes with listening ports on FreeBSD using the sockstat command:

root@bluebox:/usr/local/etc # sockstat -4l -p 443
USER     COMMAND    PID   FD PROTO  LOCAL ADDRESS         FOREIGN ADDRESS      
root     nginx   7065  5  tcp4   *:443                 *:*

In this example, the nginx process is using port 443 (just the IPv4 address...