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

Exploring virtual IPs

A virtual IP address can be used for a high-availability configuration, such as creating a Network Address Translation (NAT) in many different services on the same network port, or just for adding more than one IP address in the same network interface. In this section, we'll dive into each type of virtual IP that is supported by OPNsense and when to choose which virtual IP configuration type.

IP alias

An IP alias can be used as an additional IP address in a configured network interface. It will behave like the address configured in the interface, replying to ICMP requests (ping) and generating ARP packets on the network. The netmask must match with the network interface the IP alias will be created on; otherwise, you can set it as a single address (/32 CIDR for IPv4). You can even set an IP address from another network. There are some special cases, such as when the ISP delivers a small network (/30 CIDR) and you need to set up a high-availability installation...