In the field of information technology , attacks by viruses and malware are always latent, for this reason, experts in the field have managed to create firewalls , a very important line of defense to the network against it, to establish a series of barriers that provide security, that are more controlled and reliable for the use of external networks, such as the internet.

What is a firewall?

The firewall is a type of device that is responsible for the security of the network by the monitoring constant the traffic into and out of a computer and also decides whether to allow or block traffic in particular to improve the security of the device .

  • Definition of firewall
  • Characteristics
  • Source
  • Story
  • What is a firewall for?
  • How does it work
  • Security politics
  • Importance
  • Firewall examples

Definition of firewall

A firewall means in the Spanish language, firewall , and it is a mechanism or program through which a type of wall can be created between the internet and the equipment that is being used. It is software that has the ability to filter the traffic that enters the computer when it connects to the network. It is a type of fire wall that has the ability to filter some of the protocols, denying or allowing a specific service.



Among the main characteristics of firewalls we mention the following:

  • It has the ability to be immune to penetrations using a reliable and safe system .
  • It has control of services with which it can determine the internet services that can have access to the equipment.
  • You can determine the direction that the requirements of particular services are allowed to flow .
  • Control the way in which particular services can be used.
  • It has different levels of protection which are based on the location of the pc.
  • It can effectively block all intrusion attempts that are made over wireless networks.
  • It generates alerts that can block intrusion immediately.
  • Protects against hackers looking to get into the computer .


The origin of the firewall dates back to 1980 when the internet was a very new technology. The first firewalls that existed to protect network security were routers , which emerged at the end of this year.


The first document that was published about the firewall was in 1988 , when the filter system called firewall was developed which also had packet filtering . This is considered as the first generation of firewalls. Between 1989 and 1990 , several AT&T Bell company workers developed a second generation of firewalls. Later, third generation firewalls or application firewalls emerged . They were protectors that could act on the application layer and file transfer protocols.

What is a firewall for?

The firewall is a security element which serves to provide security to the teams whether individual, to servers or computers that are connected to the network against a series of hits that are unwanted and come from intruders trying to find how to steal confidential data , cause the loss of important information or deny services on the network .

They are essential to be able to protect personal security as well as privacy , to protect the home network or the network used by companies in order to safeguard all the information that is stored on the network, on servers or on computers. In addition, it works to prevent unwanted users who circulate on the network from having access to the computer, especially hackers and finally, it also serves to prevent denial of services attacks .

How does it work

The firewall is located exactly at the junction between two networks , usually between a public and a private network. It also has a series of subnets that can have even more firewalls and in this way, when trying to attack the network, the number of consequences can be limited since the spread of damage is immediately cut off when the firewall exists. When the traffic that occurs in the network does not comply with the rules with which the firewall has been configured, then that traffic will not have the ability to circulate in our network and, when this happens, the traffic is blocked Instantly preventing it from reaching its destination.

Security politics

Security policies are an action plan that is established with the objective of being able to avoid security risks , they are a set of rules that have a certain security level , a document that shows the commitment of a management with all the security of the information.

In the case of the firewall, the policies are related to the access control that occurs between two networks that are interconnected and is based on a mechanism that allows a reliable network to be protected from one that is not reliable. This policy says the following:

  • Access to any type of services is allowed , unless otherwise specified, this is known as permissive .
  • Any type of service is denied , unless otherwise specified, and this is known as restrictive .


The firewall is very important because it is the mechanism through which can prevent the attackers or external threats have the ability to access the system. It is the means by which adequate supervision of the network can be carried out and, by having permissions to identify and block traffic that is considered as unwanted, it provides greater protection to the system.

The firewall is the best mechanism by which it is possible to provide protection to the computer from possible intruders which may have the ability to infect and steal important data that is inside it. It is one of the mechanisms that can provide security , tranquility and confidence when browsing the web , as well as to be able to keep the information that is on a specific computer secure and confidential .

Firewall examples

Some important firewall examples are as follows:

  • Proxy firewall : this type of firewall is a device that acts as a gateway and works between one network and another. They can provide security and cache content avoiding direct connections outside the network.
  • Stateful inspection firewall : this is the most traditional type of firewall and makes it possible to block traffic depending on the criteria of the port and the protocol, in addition, it has the ability to monitor all the activity that occurs in a connection until it closes.
  • Firewall for unified threat management : this type of device combines stateful inspection functions with anti-virus and intrusion prevention. It is a very simple firewall to use.
  • Next-Generation Firewalls : Over time, firewalls have evolved significantly and companies are now creating next-generation firewalls that are responsible for stopping more modern threats as well as attacks that can occur at the application layer.

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