Firewall

We explain what a firewall is, what it is for and how this system works. In addition, the types that exist and the Windows firewall.

1. What is a firewall ?

In computer science, and more specifically in telecommunications, it is understood as a firewall (in English) or firewalls a system or device capable of allowing, limiting, Encrypt or decode communications traffic between a computer (or a local network) and the rest of the Internet, preventing unauthorized users or systems from accessing.

A firewall may well be physical or digital, that is, a device or piece of software, and in both cases it is only a first step of defense in the world of computer networks., indispensable but not sufficient to guarantee security against cyber attacks and third-party interference.

This type of technology takes its name from the mechanism for fire prevention that is usually applied in green areas or in vulnerable buildings, and which consists of a wall or a vacant area, free of any flammable content, which limits the indefinite expansion of fire in case of fire.

The precursors of the firewall arose during the 1980s, when the Internet was still a recent field of knowledge and had not yet been considered the margin of damage. or possible through hacking or cyber terrorism.

Since the first massive cyber attacks by viruses and digital worms at the beginning of the next decade, digital protection has been becoming extreme and perfecting, at the rate at which new ones appear pieces of harmful software, known as malware .

See also: Output Devices.

1. What is a firewall for?

A firewall simply serves to interrupt unauthorized or suspicious connections between a computer system or computer, and the Internet. In this way the remote communication between malicious users ( hackers ) and the local system is cut, or between pieces of malware installed furtively on the system and the outside of it, thus preventing it from operating as a spearhead in the cyber invasion.

It is therefore a guard who prevents the entry or exit of unauthorized or suspicious communications, based on discernment criteria that are updated from time to time.

1. How does a firewall work?

Firewalls distinguish between permitted and dangerous or suspicious connections, based on different procedures, such as:

• Firewall Policies Using the IP numbers and other identification systems, the firewall suspends any communication request that does not come from the internal network or from the system itself, disguising behind the internal IP the set of internal resources, so that no one can monitor them from outside.
• Content filtering Through a system of exclusion rules in which the user can have the last word, the firewall distinguishes between problematic, suspicious or insecure content, and those that remain at the user's discretion. Thus, access to Web pages or entire servers can be blocked as a precaution.
• Antimalware services . Many firewalls have built-in virus and malware definitions provided by various defensive programs, so as to also help to have the expansion of these pernicious programs.
• IPR services . This is what the Deep Package Inspection (IPP or DPI) procedures are called: Deep Package Inspection ), which adds a second security layer to the system, reviewing the deep content of the information packets received.

1. Firewall Types

There are the following types of firewall:

• Gateway application level . Applies only for specific applications considered risky, such as FTP servers or free exchange of information between users (P2P). It is usually very effective, but imposes a reduction in system resources.
• Gateway level circuit . Monitor the establishment of TCP or UDP connections through security sessions.
• Network layer firewall . It operates based on the inspection of IP addresses and the exchange of IP packets, using alternate data such as the MAC address.
• Application layer firewalls. It already operates based on applications, controlling its way of reaching the Internet, for example, by means of Proxys.
• Personal firewall. Firewall chosen by the user and installed in the system to meet the individual requirements of system use.

1. Windows firewall

The famous Microsoft operating system, called Windows, includes a firewall software among its auto defense options. This option was included in the System Security Center from its version XP Service Pack 2, seeking to offer greater control and defense of system stability for its users.

This firewall is updated together with the other Windows applications to keep up to date with regard to cyber threats, and it is activated automatically unless there is some other antivirus software or firewall that you have the connection administration privileges, in which case the Windows firewall will remain disabled.