Surely you have heard about firewalls, and you may even have had to fight with your operating system for a program to work properly. If you want to know more about this key component for the security of your local network, you just have to keep reading.

Surely, you have encountered the term computer firewall on more than one occasion, especially when it comes to improving the security of your local network or your computer or to configure your computer so that any application that needs to communicate directly with an Internet service can do it without problems.

But why do I need a firewall on my computer? Where is the fire that I must protect myself from?

According to computer network specialist the name of firewall or firewall was applied to this computer component because of its similarity with the concept of defense, containment and isolation of areas that provide these fire safety measures.

In this case, the “fire” that you must protect your computer from is the attacks that may occur (which in fact occur) from the Internet.

What is a computer firewall?

The use of this type of access control systems is as old (or as modern, depending on how you look at it) as the Internet.

At the end of the 80s, when the Network was nothing more than an innocent offspring that was taking its first steps, some of its users had already discovered that they could make mischief in other people’s computers by infiltrating through their Internet connection.

To remedy this situation that endangered security and privacy in the network, the first initiatives to reinforce the security of Internet access or from the Internet were initiated.

The firewall is the first line of defense against an attack on your network from the Internet and should be able to repel an unauthorized access before the attacker can reach your local network or your computer and, at the same time, allow normal exchange of data between your computer and verified internet services. 

For this, a series of rules are used that establish how the elements that are sent or received in your computer should be treated and if these elements can continue on their way to their destination or must be intercepted and returned to their origin.

Making an analogy, the firewall is like the doorman of a nightclub. He is the one who decides who enters and who does not.

If the owner of the club (the user of the computer in this case) has expressly told him that nobody can enter with athletic shoes, with his head covered or with a blue shirt, any client that meets any of those characteristics will be irretrievably outside the premises.

The same happens with customers who are already inside the store.

If the doorman detects that one of the customers who was already inside is trying to leave with the collection of the box that he just stole (which could also be your personal or banking information), he can block his exit so that the collection does not leave the premises and the theft does not come to completion.

Therefore, the firewall complies perfectly with the concept of danger containment and isolation to preserve the integrity of what it protects.

Types of firewalls

Although the purpose of this IT element may be perfectly clear, the firewall concept may be somewhat abstract and you are probably wondering what exactly a firewall is. Is it a computer program that I have to install, or a new device that I must install in my network? The truth is that they can be both at the same time.

There are two types of firewalls: Hardware firewall and software firewall.

Hardware firewalls are devices that are added to the local network and are located between the Internet access point and the switch that will distribute network traffic to the rest of connected equipment.

These devices analyze and filter all the traffic that enters and leaves your network and blocks those elements that do not comply with the security rules established by the administrator.

The software firewall is an application that is installed on the computer and that performs the same task as the hardware firewall. That is, analyze and filter all the elements that come out or enter your computer to block those that do not comply with the established security rules.

Differences between hardware and software firewalls

The main difference between both systems is the scope of work of each of them.

The software firewall acts on network traffic that is generated only to or from the computer on which it is installed.

In contrast, a hardware firewall is able to analyze and filter the data traffic entering or leaving a local network, regardless of the number of computers that are connected to it.

As a general rule, hardware firewalls are used in the business environment or large networks, since they require certain technical knowledge and must be configured by network administrators.

Software firewalls are aimed at end users and you can install them on your computer to improve their security, but it will only protect that computer.

You can install a hardware firewall system on your network and, in addition, have a software firewall system installed on your computer. The use of both filtering systems is not incompatible, as it can happen when two antivirus programs are installed on the same computer.

You are already using a firewall, even if you do not know it

Even if you do not know, it is more than likely that you are already using the two types of firewalls in your network simultaneously.

Most current routers incorporate a module that performs the basic functions of a hardware firewall, although in many cases this module is configured in the most permissive filtering mode.

This permissive mode allows access to almost all the traffic on your network, unless a specific block is specified. But with the appropriate configuration, this security element will constitute an effective system of containment in front of accesses not allowed.

In addition to having a hardware firewall system built into your router, you also have a basic software firewall built into your operating system.

As in the case of your router, the configuration of the firewall integrated into your computer’s operating system is aimed at a permissive filtering, so that a user without technical knowledge can navigate with a minimum of security, but if it has to be complicated with configurations that you do not understand.

With the proper configuration, this application, although in a very basic way, will be able to protect your computer from any external attack.

In computer science, absolute security does not exist

If you think you are safe from cyber-attacks and your Cyber Safety just by using a Linux operating system or any of Apple’s computers, we have bad news for you. Nobody is safe from one of these attacks since these attacks can use vulnerabilities in your browser or in any of the programs that you already have installed to act at will.

Both the different distorts of Linux, as well as the operating system of your Mac, have their respective basic software firewall systems, but in some systems, the firewall is deactivated in origin and it must be the user who activates it.

Activating the firewall of your Mac or your PC with Linux,even with the configuration of origin, will provide extra security to your computer.

Why do I need a firewall if I already have an antivirus?

Many users ask themselves that same question. The analogy of the disco doorman may be useful again to explain the difference between the two protection systems.

We said that the firewall was the doorman of the nightclub that monitors the accesses and is in charge of analyzing and filtering the customers who come and go and keep the doors open or closed.

Obviously, this goalkeeper cannot know what is happening inside the premises.

To ensure that everything inside the room runs safely, both for customers who are already inside, as for the business itself, is responsible for the security staff of the room, which in this case is the antivirus software.

In some cases security software companies offer security suites or extended packages of their products that include both antivirus and a specific firewall software. Usually this type of products are associated with the payment of a license for use.

However, to enjoy good protection of your equipment you do not always have to go through the box. There are free firewalls that allow you to get much more effective protection than the firewall of your operating system can provide.

Although the antivirus and the firewall are from different developers, both can coexist in the same environment without any problem or incompatibility because, as you could see in the analogy of the disco doorman, each one fulfills a different security task inside of the system and its functions do not overlap.

You have the last word

Whether it’s a free firewall, a security suite that integrates it with the antivirus or a hardware firewall, the entire responsibility for the configuration of the firewall rests with the user.

Software firewalls, the most user-friendly ones, have an initial configuration phase in which the firewall “learns” which services to block and which ones to block.

To do this, ask the user directly what he must do with each of the requests for access or output he receives. Depending on the response obtained by the user, a new rule will be created and the firewall will no longer ask about that access.

This, at the beginning, can be a bit heavy for the user, but if you keep at bay the temptation to tell everything you do, you will get a much more secure system and in a short time you will forget that it is installed on your computer. Will perform your task effectively and in absolute silence.