We explain what a firewall is, what it is for and how this system works. Also, the types that exist and the Windows firewall.
What is a firewall?
In computing, and more specifically in telecommunications, it is understood by firewall (in English) or firewall to a system or device capable of allowing, limiting, encrypting or decoding communications traffic between a computer (or a local network) and the rest of the Internet, preventing unauthorized users or systems from having access.
A firewall can either be physical or digital, that is, a device or a piece of software, and in both cases It constitutes just a first step of defense in the world of computer networks essential but not sufficient to guarantee security against cyber attacks and third-party intrusions.
This type of technology borrows its name from the fire prevention mechanism that is usually applied in green areas or vulnerable buildings, and which consists of a wall or a vacant area, free of any flammable content, which limits the indefinite expansion of the fire. fire in case of fire.
The precursors of the firewall emerged during the 1980s when the Internet was still a recent field of knowledge and the margin of possible damage through the Internet had not yet been considered. hacking or cyber terrorism.
Since the first massive cyber attacks by viruses and digital worms at the beginning of the following decade, digital protection has been becoming more extreme and perfected at the rate at which new pieces of harmful software, known as malware.
See also: Output devices
What is a firewall for?
A firewall serves, simply put, to interrupt unauthorized or suspicious connections between a computer system or computer and the Internet. In this way, remote communication between malicious users is cut off (hackers) and the local system, or between pieces of malware stealthily installed in the system and outside it, thus preventing it from operating as a spearhead in the cyber invasion.
It is, therefore, about a guard who prevents the entry or exit of unauthorized or suspicious communications based on discernment criteria that are updated from time to time.
How does a firewall work?
Firewalls distinguish between allowed connections and dangerous or suspicious ones, based on different procedures, such as:
- Firewall policies Using IP numbers and other identification systems, the firewall suspends any communication request that does not come from the internal network or the system itself, disguising all internal resources behind its own IP, so that no one can monitor them from outside.
- Content filtering Through a system of exclusion rules in which the user can have the final say, the firewall distinguishes between problematic, suspicious or insecure content, and those that are left to the user's discretion. Thus, access to entire Web pages or servers can be blocked as a precaution.
- Anti-malware services Many firewalls have built-in virus and malware definitions provided by various defensive programs, so as to also help prevent the spread of these malicious programs.
- IPR Services This is what the Deep Packet Inspection (IPP or DPI) procedures are called: deep Package Inspection), which adds a second layer of security to the system, reviewing the deep content of the received information packets.
Firewall types
There are the following types of firewall:
- Gateway application level. It applies only to specific applications considered risky, such as FTP servers or free exchange of information between users (P2P). It is usually very effective, but imposes a drain on system resources.
- Circuit at catwalk level. Monitors 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 alternative data such as the MAC address.
- Application layer firewall It already operates based on applications, controlling their way of reaching the Internet, for example, through Proxies.
- Personal firewall. Firewalls chosen by the user and installed in the system to meet the individual requirements for system use.
Windows Firewall
Microsoft's famous operating system, called Windows, includes firewall software among its automatic defense options. This option was included in the system's Security Center starting with its XP Service Pack 2 version seeking to offer greater control and defense of the stability of the system for its users.
This firewall is updated along with other Windows applications to stay up to date with cyber threats, and activates automatically unless there is some other antivirus or firewall software that has connection management privileges, in which case the Windows firewall will remain disabled.
