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

Reading logs and troubleshooting

Web proxy troubleshooting strongly relies on log reading, so it is fundamental to know how to read logs. Despite the web GUI having a logs page, I will focus on the command-line interface (CLI) in this section. Why? Because web proxy logs are really dynamic and most times will demand filters (using the grep command, for example) and will help you to see things happening in real time.

Before touching the keyboard to log on to the CLI, I recommend you this must-read Squid documentation:

https://wiki.squid-cache.org/SquidFaq/SquidLogs

Pay special attention to the Squid result codes and HTTP status codes sections. Without knowing what these codes mean, reading the logs would be like reading a foreign language that you don't speak. Maybe you'll be able to understand part of the information, but not all of it.

Log files

The web proxy log files are located in the /var/log/squid/ directory and are described in more detail here:

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