Types and Functions of Firewall in Computer Network

A firewall in computer network is a security feature that could either be hardware- or software-based and prevents unauthorized access to the network. It keeps a close eye on all the incoming and outgoing traffic using a well-defined set of security rules to detect and prevent risks.

The Firewall in computer network can take four actions or follow four steps to ensure the security of the system. It could either choose to ALLOW, that is, let the traffic gain access and pass through the firewall, or REJECT, which means to decline the traffic access to the firewall while sending feedback to the sender with an “unreachable error.” ACCEPT is much similar to that of allow but the only difference is that it is for some specific type of traffic and the fourth action is DROP, which means declining the traffic access but unlike REJECT, no feedback or reply is sent.

The rates at which cyber crimes are increasing are very fast and individuals, companies and private organizations must look for every possible way to ensure that their information is well-secured and private. A firewall in computer network is one of the best options. This is an excellent security device that can help you safeguard your network and device from unauthorized users.

A firewall is like a wall—an obstruction or obstacle that prevents the easy access of private internal networks. A firewall in computer network makes use of policies and security actions that have been established in an organization to filter incoming and outgoing traffic.

In this article, we’ll be looking at firewalls in computer networks, how they work, their functions, and everything you need to know about them.

What is a Firewall in Computer Network?

A firewall in computer network is a security system that is used to monitor and control the flow of traffic between a secured network and an untrusted network. It helps to keenly watch and filter incoming and outgoing network traffic in compliance with the laid down security policies that have been set out by an organization.

Just as the name fire-“WALL”, a firewall in computer network acts as a defensive wall between a privately secured network and the public internet.  This is to prevent unpermitted access to a network. A practical example of this could be the way a farmer builds a wall around his farm to prevent unpermitted access to the farm from thieves or even wild animals. This is the same way a firewall in a computer network works. They are used to keep the computer network safe and secure.

Apart from keeping the system safe, secure and free from cyber attacks, a firewall in computer network can also be used to control and monitor the flow of information and restrict the types of services that are allowed on the network.

One practical example of how a firewall can be used to control and monitor the flow of information is through the use of defined policies and rules. These defined policies can be used to ACCEPT or BLOCK some specific type of traffic. A Good example is the use of Facebook or TikTok in China.  It is no news that the use of Facebook and TikTok is banned in China; this is made possible through the great firewall of China.  Citizens or tourists staying in China can access the Internet and other authorized apps but they are not allowed to use the ones that have been banned. The firewall has been configured to block access to these social media apps once you’re within the China geographical zone.  A firewall can be implemented as hardware, software, or a combination of both.

The Different Types of Firewall in Computer Networks

There are different types of firewalls in computer networks and we’ll be looking at some of them briefly.

1. Packet Filtering

A packet filtering firewall in computer network helps to monitor and control the flow of data to and from the network. Packet filtering firewalls help control the transfer of data in the network; they allow or block the transfer of data based on the packet’s source address, the destination address of the packet and the application protocols to transfer the data.

2. Proxy Service Firewall

This type of firewall protects the network by filtering messages at the application layer. A proxy firewall is a type of firewall that acts as a gateway between a network and the internet. In other words, a proxy firewall acts as a “gateway” for all the traffic that passes through it.  Before any traffic is allowed to pass through, the proxy firewall accepts and examines any request from the network.  The proxy service firewall is also useful in protecting the network by securing its true identity and location from the internet.

3. Stateful Inspection Firewall

The next type of firewall we’ll be looking at is the stateful inspection firewall. This type of firewall gives access to traffic based on the connections. It can choose to allow or deny traffic access after examining it. Not only is the Stateful Inspection Firewall secured, but it also helps to monitor and keep track of all the connections that have been made. This type of firewall is commonly used in large organizations.

4. Next-Generation Firewall

A next-generation firewall (NGFW) does the same thing as the stateful inspection firewall does but at an advanced level. The next-generation firewall is very secure since it provides a very high level of security. It has the ability to examine and access encrypted traffic, which is why it is commonly used in environments that require a high level of tight security, like banks, government agencies and other top private organizations.

5. Unified Threat Management (UTM) Firewall

A unified threat management (UTM) firewall is a firewall that has been designed to be very easy to use. The Unified threat management firewall combines the security features of both the next-generation firewall and the stateful inspection firewall. It also has other advanced features like anti-filtering, content and web filtering, and anti-spam. All these features enhance the security of this firewall.

The unified threat management firewall can also be used to reduce the amount of traffic a network has since it has features that can be used to filter out unwanted or malicious traffic before it gets to the network. This can help improve the overall performance of the network.

6. Threat-Focused NGFW

A threat-focused next-generation firewall (T-NGFW) is a type of firewall that has been designed to scan,  detect and prevent advanced threats. This type of firewall is used by private organizations that are at risk of advanced threats.

Functions of Firewall In Computer Network

There are a lot of firewall functions in computer networks and we’ll be looking at them briefly. One of the major functions of a firewall in computer network is to keep it secure. It also helps to monitor and filter the inflow and outflow of traffic following a set of defined rules. These rules can be used to allow, accept, or deny the flow of traffic based on some factors, such as the IP address, port, protocol or application.

Another function of a firewall in a computer network is that it can be used to control and monitor network traffic. This can help to easily detect and point out any threats or malicious activities. The firewall also blocks and denies the flow of traffic from unknown or unwanted sources since it keeps close track of the network traffic. Just as we discussed earlier, every single piece of data that enters or leaves a computer network must go through the firewall.  Remember, a firewall in computer network acts as a middleman between the internal network and the public internet.


We’ve looked at what a firewall is in computer network, the different types of firewalls in computer network, and some of the functions of a firewall in computer network.  As we conclude, it is important to be informed that the presence of a firewall on your computer does not exempt you from threats.  There are still some possible risks or threats, like malware, that can have a huge impact on your network.

Malware such as ransomware, viruses, worms, spyware, phishing,  Trojan horses, etc. can gain access and infect and control some areas of your computer.

Remember that one of the primary functions of a firewall in computer network is to keep the network secure from cyberattacks. However, you should be informed that a firewall cannot keep your computer safe from unauthorized access. That is why it is always said that passwords to your computer should be kept private.  If handled carelessly, then a third party can have access to your device

. A firewall cannot protect your computer from theft. If you misplaced your computer or your computer was stolen, a firewall cannot deny access or block another person from gaining access to it. We’ve come to the end of this article and I’m sure by now you should have a good understanding of the role of firewalls in a computer network and also what a firewall does not do.




Leave a comment