Computer Firewall  What is it? + What is it for? List ▷ 2020

To manage access of different users to network services or to be able to record all the data packet inputs and outputs to it, it is necessary to install a firewall.

A firewall is not only capable of the above, but can also control the different types of protocols used in a network and manage the applications that can access the Internet.

In this article we will talk about the most important concepts that you should know about a firewall, its implementation and configuration, you will also be able to know if an antivirus is the same as a firewall, among other things.

What is a firewall in computing and what is it for?

A firewall or commonly called in English “firewall” are hardware supplements or devices or software that allows manage all the inputs and outputs between two networks or between two or more computers belonging to the same network.

That is, with a firewall we filter all the inputs and outputs that do not comply with certain “rules” that we have established previously. If a data set complies with the established protocol, it will be able to enter or leave the network that we want to protect.

With this concept we can define why a firewall is installed. Among the different reasons we can highlight:

  • A firewall protects security and privacy of the computers and networks in which it was installed.
  • Protect all information or data blocks owned or operated within the network. For many companies this point is the main reason why they use a firewall.
  • With a firewall you can prevent intruder access or hackers that could affect computers or the network.

Avoid so-called “DDoS attacks” in which legitimate users cannot access the network or computer.

Firewall vs Antivirus Are they the same tool? Differences

Firewall vs Antivirus Are they the same tool?  Differences

While the firewall and antivirus belong to and serve computer security, there are substantial differences between them.

To clarify the idea we are going to detail some differences:

  • The antivirus is software that is installed in a mobile or on a computer, Meanwhile he firewall is software, but it can also be a hardware. The latter is less used in cell phones.
  • The mission of antivirus is to detect a virus or any malware and destroy it, while a firewall its mission is that information can not enter or exit if they do not comply with the rules
  • They have one point in common, in networks and computers you only need one of each. That is, it is not necessary to install several of these because we could have adverse results.
  • The firewall with the antivirus is complementary each other, that is, to have efficient computer security, the presence of both is necessary. This complement system is highly recommended for companies.

History and evolution of firewalls, how many generations have existed until now?

In 1980, the term firewall began to be used for the first timeAt this time, the Internet was a new network from the point of view of its use and connectivity.

The first firewalls that existed it was the routers, which kept the different networks to which they belonged separate from each other.

Major security attacks emerged in the late 1980s of the Internet, there are different examples in which it was possible to manipulate everything from espionage systems to the large-scale attack of the so-called virus “the Morris worm”, which was not malicious.

From this moment on, new generations of the firewall began to emerge, differ from each other by their degree of advancement and approachability in terms of safety.

History and evolution of firewalls, how many generations have existed until now?

We detail each of these generations of firewalls below.

First generation

This generation points to network firewalls, which were born in 1988, the company Digital Equipment Corporation (DEC) designed a system for packet filtering. This generation is known as “packet filtering.”

Engineers developed rules to be able to filter data packets traveling through the network, that is, if a packet matches the rules that were previously established, the packet will be accepted, otherwise it will be discarded silently or it will be discarded and rejected.

For the latter case, a response with an error code to the sender of that data packet.

Second generation

The second generation arises between the years 1989 and 1990, engineers from the laboratory firm “AT&T Bell” They designed a firewall in which individual packages will be placed within a series of packages.

This type of technology is commonly known as packet health inspection hence the name of “state firewall”. It consists of keeping a record of all the connections that go directly through the firewall, registering whether the packet is wrong or not.

Third generation

The third generation is known as “application firewall”, the firewall acts on the layer called “Application” of the OSI model, which shows the different stages that a network has in its operation.

This firewall is aimed at detect transfer protocols of the files, and if a protocol is not desired it will be rejected immediately.

The great advantage that these firewalls have is that they can filter higher layer protocols, always speaking according to the OSI model. Ie layers like HTTP, TCP and TFTP among others.

It has a disadvantage which is slowness they present with respect to Second Generation firewalls.

What are the main types of firewalls and their characteristics?

There are two types of firewalls, each of them has particular characteristics. We detail below:

Software Firewall

Software firewalls are programs that generally come loaded with the operating system. For example, Windows brings its built-in firewall for free, it does not present major problems when configuring and in most cases this type of software is free, although there are also paid versions in which the needs of each user can be modified or adjusted.

The main job these firewalls perform is to control all data traffic that moves through networks in relation to the Internet. It is also aimed at blocking network elements and connections that may have a potential problem for the computer or the network to which it belongs.

They almost always do not need to add hardware for their installation, it is done in a few steps that are not complicated. In the paid versions, the provider grants certain benefits that are perfectly adjusted to the customer’s needs, making the steps even simpler.

Hardware Firewall

When we talk about a hardware firewall we are talking about all those firewalls that are not installed on a computer that belongs to a network, rather we are talking about those that are installed in physical devices that we use for the Internet connection, for example, the router.

The main advantage of these firewalls is that all computers connected to the router that already have the firewall installed will have the firewall in each of them directly.

To configure the firewall parameters on the router it is advisable to do it through professionals in the sector. If for some reason the configuration is not correct, the network users will not be able to carry out their jobs in a normal way because their activities will be suspicious for the router.

Advantages and disadvantages of using a firewall Are they really effective?

Advantages and Disadvantages of Using a Firewall Are They Really Effective?

Like all things computer science, firewalls have their advantages and disadvantages when installed on a network.

Next, we will name the most important ones:


We can mention the following as strengths of a firewall:

  • One of the main reasons why a firewall is installed in a company is that they define what information will each user handle of the network
  • Use the direct access to protocols to be used in the network
  • Control the intruder entry
  • If the source is not legitimate, it will block all the information that comes from it
  • Protect hardware, since if an intruder released a virus, it can cause irreparable damage to physical equipment. With the implementation of a firewall the virus can be stopped


Among the disadvantages we will have to mention:

  • The firewall does not protect against attacks when they do not pass through of the firewall
  • If there are network users be negligent, the firewall won’t protect of misuse of them since they were able to enter the network correctly

If there is access by legitimate users, they can create copies of the information and the firewall will not be able to protect on the subject

List of the best firewalls that you can install on your computer

List of the best firewalls that you can install on your computer

We present you the list of the best firewalls you can install on your computer or network. Each of them have really very good characteristics, which makes them unbeatable when it comes to filtering data blocks.

Windows Firewall Defender

The quintessential firewall, it comes included or pre-installed with the Microsoft operating system. It is free and is considered one of the most efficient and least invasive for the user.

To activate the firewall we will follow the following steps:

  • On the screen we look for the Windows logo located in the lower left part
  • We select “Start
  • We seek “Setting” and we click
  • Next, we choose “Update and security “
  • Windows security
  • And we choose “Firewall and network protection
  • We select the network profile we need, and then
  • We change the setting to “Windows Defender Firewall “
  • We click on “Activated”

This software is produced by Check Point Company, and is listed as one of the oldest and most efficient that exist today.

They have two versions, a free one that includes intrusion detection and can control which programs can create connections within the network or within the computer. It also protects against sending data packets.

For the paid version, it also offers more complete services and can be customized according to the user’s needs. It is available for the Windows operating system.


This a firewall of Open Source It allows blocking traffic to and from the internet by generating a black list of hosts, it also determines a list of IPs that can be rejected.

It is available in a free version for Windows.

Download PeerBlock Windows


Considered by many to be the best free firewall that exists today. Among its advantages it has the characteristic of being a program that is not complicated to install and use, it is easy and above all it is fast.

Download GlassWire Windows

If you have any questions, leave them in the comments, we will answer you as soon as possible, and it will surely be of great help to more members of the community. Thank you! 😉

You may be interested:

Rate this post

Leave a Comment