What is a Firewall? Firewall Meaning and Explanation


For ages humans have protected their land, home, people, crops, and whatever was precious to them sometimes also by erecting high walls as a defence.

Fast forward to present modern era, and things have not changed much, as with the dawn of technology the sturdy old physical wall was replaced by a digital one instead – a firewall.
Though hardware versions exist too.

In a nutshell, a firewall is a network security device which screens inbound and outbound traffic, allowing or stopping data in line with a set of rules.

Let us go deeper though to see why a firewall is important and when it is utilised. Guess what, we are betting that this piece will capture your attention, as there exist many types of firewalls which may hold multiple facets, so rest assured you will find the firewall world interesting and see first-hand the importance of implementing it within your business or at home.

Brief History of Firewalls

Firewalls have indeed come a long way, and it stands to reason that they are regularly updated in line with the development of technology.

Starting in the 1980s as packet filters, firewalls were networks established to scrutinise packets or bytes shifted between computers.

Below we list the generations from which the firewall was eventually created:

Gen 1 – Virus

In the late 1980s stand-alone PC`s were attacked by viruses which affected all trades and started driving anti-virus products.

Gen 2 – Networks

Following another wave of virus attacks from the internet which again embattled all businesses in the mid 1990`s, the necessity for a creation of a firewall was evident.

Gen 3 – Applications

Intrusion Prevention Systems Products (IPS) were introduced to assist besieged commerce, tackling the exploitation on vulnerabilities in applications in the early 2000`s.

Gen 4 – Payload

Anti-box and sandboxing products were introduced around 2010, following a rise of targeted, unidentified, elusive and polymorphic attacks which plagued various markets.

Gen 5 – Mega

Using advanced attack tools, a vast-scale, multi-trajectory, mega assault around 2017 drove advance threat prevention solutions, which is still ongoing.  

Firewalls have developed in various forms along the years and, as we will see, they all support an extensive diversity of purposes and skills including built-in features.

How Does a Firewall Function?

When implemented a firewall is taking away all the guesswork from your system which is in turn entrusted to it.

This means that any incoming access or tempted entries will need to deal with the firewall first, as it will scrutinise, scan, recognise and then allow access as per set instructions which list the authorised users or data that can enter.

On the other hand, if any malware, unauthorised users, or any other malicious attempt is detected trying to get into your network, the firewall will block it in its path.

Therefore, a firewall is essential for corporates or companies, but also for personal use, as it will further protect your precious data from any hackers and unauthorised persons.  

Types of Firewalls

Good to know that a firewall can be bought in two versions – software and hardware.

The software will be in a form of an installed program which regulates traffic through port numbers and applications, while a hardware one will be an implemented piece of equipment situated between your network and the gateway.

Furthermore, different kinds of firewalls are on offing, and here we list some of the most popular ones, their designations and what they do:

  • Next-generation Firewalls (NGFW)
    Combining traditional firewall technology with supplementary functionalities, like encrypted traffic scrutiny, Intrusion Prevention Systems (IPS), antivirus, and especially Deep Packet Inspection (DPI) which doesn`t look at packet titles only but examines their insides too, which better enables it to identify, categorise and stop any malicious data.
  • Proxy Firewalls
    These types of firewalls monitor traffic for HTTP and FTP, using both stateful and DPIs to detect malicious traffic. This firewall acts as an intermediate between two end systems, with the client sending a request to the firewall which in turn evaluates against a set of security rules, consequently allowing or blocking said request.
  • Network Address Translation (NAT) Firewalls
    NAT are like Proxy as they act in the middle between a group of PCs and exterior traffic. It allows various devices holding their own IP addresses to link to the cyberworld utilising a single IP address, misleading any hacking attempts.
  • Stateful Multilayer Inspection (SMLI) Firewalls
    Similar to NGFW, the SMLI also checks packets comparing them to a known list of trusted ones, allowing them to access only if they manage to pass each layer independently. Ultimately ensuring that communication is processed with trusted sources.

Do Firewalls Protect Against Viruses?

First off the bat, we need to understand the difference between a firewall and an antivirus. The latter protects the file system against unwanted programs, while a firewall assists to keep attackers or external threats at bay and prevents them from getting access to the system in the first place.

As mentioned, firewalls do block any unrecognised or unauthorised access, even malware, but it should never be your only line of defence. If a cybercriminal is using some new type of viruses, a firewall may not be enough to recognise and halt the malevolent intrusion, so we suggest that a renowned antivirus setup which is regularly updated is also installed along the firewall.

In Conclusion

Firewalls were primarily created to protect our software from malware or any malicious unauthorised users to access our working or personal data.

It is pertinent to mention that firewalls can also be misused or abused, like we find in certain countries were the Government limits the internet for whatever reasons or rationales.

However, in democratic, progressive and contemporary nations, firewalls exist to deter any unofficial people from accessing specific data, thus blocking those who insist trying like hackers.

As we saw though, for firewalls to keep functioning properly they need to be updated in tandem with technology to keep abreast of the continuous changes within the vast tech realm.