Types of firewalls: Everything you need to know

In a world where cybersecurity is constantly evolving, knowing the different types of firewalls and how they work is crucial to protecting our networks and devices. These firewalls act as the first line of defense by blocking cyber threats and unauthorized access to our systems, and their importance has grown in parallel with the sophistication of attacks that seek to breach the security of organizations and end users.

Over the years, firewalls have evolved from simple packet filters to advanced solutions that integrate intrusion prevention, application filtering, and more. In this article, we'll break down the main types of firewalls out there, their features, advantages and disadvantages, and how they've evolved to address the most complex cybersecurity threats.

What is a firewall and how does it work?

Un firewallA firewall, or firewall, is a security tool that controls incoming and outgoing traffic on a network with the goal of allowing only secure connections and blocking potentially dangerous ones. Through a set of predefined rules, a firewall can analyze data traffic, divide it between what is safe and what is not, and act accordingly. Whether at the network or individual device level, its primary function is to protect against malicious activities that threaten the integrity of data on the network.

The firewall can make decisions to allow or deny access based on different parameters, such as IP addresses, ports used or even the protocols used in connections. In addition, some more advanced firewalls allow inspections at deeper levels, establishing additional layers of protection.

Types of firewalls based on their location and application

Depending on where the firewall is installed, we can divide them into two main types: hardware firewalls and software firewalls.

Hardware firewall

Un hardware firewall It is installed on a physical device, which is usually located at the perimeter or near the entry point of a network. Hardware firewalls are usually found on routers or dedicated computers and protect all devices connected to the network. This allows multiple devices to benefit from the firewall's security without having to install individual software on each one.

For business networks, industrial or corporate, hardware firewalls are usually more robust and require a high level of customization by security professionals. While they are more expensive and complex to manage, they provide excellent protection for environments where multiple layers of defense are necessary.

Software firewall

Furthermore, the software firewall It is installed directly on individual devices, such as computers or servers. It is usually integrated into the operating systems of almost all devices, and its objective is to protect that specific device from attacks. Although it does not generally protect an entire network, it can be a very useful tool in combination with a hardware firewall.

One of the main benefits of a software firewall is its ease of installation and its ability to give us direct control over the incoming and outgoing traffic on our device. However, because it runs on the device itself, it can consume resources and slow down the system.

Types of firewalls according to the traffic filtering method

Aside from their location, firewalls can also be classified by how they handle network traffic. Below, we will detail the different types of firewalls based on their filtering methods.

Packet Filtering Firewall

This is one of the most basic types, and its function is to make decisions based on the IP addresses, ports o protocols. This system does not perform deep content inspection or save connection status. Although they are fast and consume few resources, their security is limited, since any traffic passing through an approved port could contain malicious code.

proxy firewall

This type of firewall acts as a intermediary between the internal and external network, preventing direct connections between devices. It evaluates the information packets that arrive and only allows access if it meets the requirements. safety criteria. Although this type of firewall offers greater protection, it can also reduce performance due to additional processing of the packages.

Stateful Inspection Firewall

A stateful inspection firewall not only checks the packet header, but also analyzes its Actual state within the connection. This allows ports to be opened and closed dynamically, ensuring better protection. Its ability to detect and remember previous connections makes it a more secure solution than the standard packet filtering firewall.

Next Generation Firewall (NGFW)

El Next Generation Firewall It not only performs the traditional functions of firewalls, but goes further, incorporating additional security tools such as intrusion prevention’s most emblematic landmarks, the advanced application recognition and the ability to analyze traffic at the highest layers of the OSI model. This type of firewall is very beneficial for large companies that need comprehensive protection against advanced threats such as malware, vulnerability exploitation, and application attacks.

Differences between firewalls according to their structure

Another way to classify firewalls is by their structure. Firewalls can be implemented as hardware, software, or even cloud services. Below we break down the main types of firewall structure that currently exist:

• Hardware Firewall: These firewalls are typically found on dedicated physical appliances that protect multiple devices on a network. While powerful, they require skilled personnel to deploy and may be limited by the hardware they run on.
• Software Firewall: They are easier to implement and are installed directly on the device to be protected. Although they consume system resources, they are suitable for individual users and small businesses.
• Cloud Firewall: These are highly flexible solutions that protect data and resources in cloud environments. They take advantage of the benefits of virtualization and are designed to operate in scalable environments, making them ideal for companies migrating their infrastructure to the cloud.

Cloud firewalls continue to gain popularity as they offer scalable protection and are tailored to the needs of companies operating in cloud environments. In addition, the flexibility they provide allows for easy deployment anywhere in the world.

Cases and practical examples of use

Depending on the scenario, some types of firewalls are more suitable than others. Here are some representative examples:

Packet Filtering Firewall in Small Business: Many small businesses opt for this type of firewall due to its low cost and ease of implementation, although it does not offer an advanced level of protection.

Stateful Inspection Firewalls in Large Educational Organizations: Universities often need a balance between security and performance, and stateful inspection firewalls allow them to manage large volumes of data without compromising efficiency.

NGFW Firewalls in Multinational Corporations: Large enterprises that manage extensive infrastructure often choose next-generation firewalls to protect against advanced threats and ensure comprehensive security.

Firewalls are a fundamental piece of the modern cybersecurity world. As we have seen, there is no single type of firewall that is ideal for all situations. Each organization, whether large or small, must evaluate its own needs before deciding on a specific solution. Over time, the evolution of firewalls has allowed for increased security barriers, and while none of them provide a perfect solution against all threats, they are an extremely useful tool for mitigating risks.