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 afirewall?
In computing, and more specifically in telecommunications, is understood by firewall (in English) or firewall to a system or device capable of allowing, limiting, encrypting or decoding communication 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 be either physical or digital, that is, a device or a piece of software, and in both cases it constitutes only 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 technologies They take their name from the fire prevention mechanism that is usually applied in green areas or vulnerable buildings, and that consists of a wall or a vacant area, free of any flammable content, which limits the indefinite expansion of the 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 damage possible through the Internet had not yet been considered.hack or cyber terrorism.
Since the first massive cyberattacks by digital viruses and worms in the early 2000s, digital protection has exploded and refined as new pieces of malicious software, known asmalware.
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 the communication remote between users malicioushackers) and the local system, or between pieces of malware stealthily installed on the system and outside of it, thus preventing it from operating as a spearhead in the cyber invasion.
It is, therefore, a watchdog that prevents the entry or exit of unauthorized or suspicious communications, based on criteria of discernment that are updated from time to time.
How does a firewall work?
Firewalls distinguish between allowed and dangerous or suspicious connections, 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 from 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 last word, the firewall distinguishes between problematic, suspicious or unsafe content, and those that are left to the user's discretion. Thus, you can block access to websites or entire servers as a precaution.
- Antimalware services. Many firewalls have built-in virus and malware definitions provided by various programs defensive, so as to also help to have the spread of these pernicious programs.
- IPR services. The Deep Packet Inspection (IPP or DPI) procedures are called this:DeepPackage Inspection), which adds a second layer of security to the system, reviewing the deep content of the information packets received.
Firewall types
The personal firewall is chosen and installed by the user.
There are the following types of firewall:
- Gateway application level. Applies only to specific applications considered risky, such as servers FTP or free exchange of information between users (P2P). It is usually very efficient, but it imposes a drain on system resources.
- Walkway level circuit. 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 alternate data such as the MAC address.
- Application layer firewall. It already operates on the basis of applications, controlling its way to reach the Internet, for example, through Proxys.
- Personal firewall. Firewalls chosen by the user and installed in the system to meet the individual requirements of use of the system.
Windows firewall
The famous operating system from Microsoft, called Windows, includes a firewall software among its self-defense options. This option was included in the System Security Center from its XP Service Pack 2 version, seeking to offer greater control and defense of system stability for its users.
This firewall is updated along with the other applications of Windows to stay up-to-date on cyber threats, and is activated automatically unless there is some other software antivirus or a firewall that has the connection management privileges, in which case the Windows firewall will remain disabled.