What is a Firewall?

What is a Firewall?

6 mins read253 Views Comment
Anshuman Singh
Senior Executive - Content
Updated on Mar 19, 2024 14:57 IST

In today’s era, where the use of the internet and technology is increasing rapidly, new cybersecurity threats are also rising at an alarming rate. These threats have become a critical concern for organizations and individuals alike. A firewall is one of the most important tools that you, as an individual or an organization, can use to protect your networks.


Firewall in computer acts as a barrier between a computer network and the internet that analyzes, restricts, or allows incoming and outgoing traffic based on an organization’s previously established security policies.

Before diving deeper into the article, let’s first go through the list of topics listed under the table of contents we will cover.

Table of Contents (TOC)

What is a Firewall?

Firewall Definition: A firewall is a firmware or software that filters incoming and outgoing data based on an organization’s previously established security policies. 

In layman’s terms, a firewall is a piece of software or hardware that monitors and controls traffic between a computer network and the internet. There are several types of firewalls, such as packet filtering firewalls, stateful inspection firewalls, circuit-level gateways, proxy firewalls, next-generation firewalls, cloud firewalls, and so on.

Individuals or organizations can choose from various types of firewalls available as per their requirements and business needs. We will discuss the different types of firewalls in the later section of the article.

How Does a Firewall Work? 

You can think of a firewall as a security guard for your computer network. It analyzes each data packet that enters or leaves your network on the basis of a set of rules. Once it has analyzed the data packet, it decides whether to allow the data packet to enter or leave or should be blocked. In simple terms, you can consider a firewall as a security guard that only lets those people enter whom you trust.


Firewalls only allow the data that you have especially allowed. It decides whether the traffic is good or bad and either lets it through or blocks it based on the rules you set up. These rules look at things like where the traffic is coming from, where it is going, and what is in it. Firewalls will block traffic from suspicious places to protect your network from cyberattacks.


You can also explore: What is a Salami Attack and How to protect against it?

Types of Firewall

There are different types of firewalls, such as:

Firewall Type Description
Packet filtering It analyzes the packet headers to see where the traffic is coming from and where it is going. After analyzing, it decides whether to let the traffic through based on predefined rules.
Stateful inspection It analyzes not only the packet headers but also the contents of the packet to determine whether it is safe to let through. This firewall also remembers the previous traffic, which helps it make decisions.
Circuit-level gateway It works at the session layer of the OSI model and makes decisions based on whether or not a connection is authorized. This firewall does not examine the contents of the traffic.
Proxy It acts as an intermediary between the client and the server, and it can examine traffic for threats before forwarding it on.
Next-generation It combines the features of traditional firewalls with other security technologies, such as intrusion prevention, application awareness, deep packet inspection, etc.
Software It is installed on a computer and runs as a software application, protecting that specific device.
Hardware It is a standalone device that provides firewall protection for an entire network. This type of firewall often has greater processing power than a software firewall.
Cloud It is hosted in the cloud, providing protection for devices and data that are accessed over the internet. (Must explore- AWS Firewall Manager)

If you want to explore more about different types of firewalls, you can explore: What are the Different Types of Firewalls?

Advantages of Using a Firewall 

Here are some of the advantages of firewalls:

  • Protection from viruses: A computer firewall provides security to a computer by creating a shield between the computer and unwanted sources. Thus, before any virus or trojan can infect or harm the computer, it blocks them as per predefined rules.
  • Monitors traffic: It continuously analyzes and monitors all the incoming or outgoing traffic, as some can be malicious or from a dangerous source that can harm the computer.
  • Decreases the chance of hacking: It prevents hacking or decreases the chance of its occurrence by blocking or dropping the data packets that an attacker might have sent in order to infiltrate the system and perform malicious activities.

You can also explore: Difference Between Virus and Worm

Disadvantages of Using a Firewall 

Here are some of the disadvantages of firewalls:

  • Expensive: Hardware firewalls are quite expensive compared to software firewalls and require IT professionals to maintain them. Hence, increasing the cost.
  • Not 100% effective: They do not provide complete protection against hackers as it is ineffective against malware attacks.
  • Degrades performance: It degrades the performance of processing power and RAM resources even when running in the background. Hence, the overall performance of the system goes down.

How to Choose the Right Firewall? 

Here are some of the factors to consider while choosing the right firewall for your organization or as an individual are:

  • Size of the network
  • The complexity of the network
  • Level of security required
  • Budget available
  • Ease of use
  • Management
  • Compatibility with other security tools and systems
  • Security policies, etc.

You should also explore: Types Of Hackers To Be Aware Of In 2023

To help you grasp what a firewall is, here's an animated video by PowerCert:


In this article, we have covered what firewalls are. We have also explored its types, working, advantages, disadvantages, etc., in great depth. If you have any queries related to the topic, please feel free to send your queries to us in the form of comments. We will be happy to help you.

Happy Learning!!


What is the primary purpose of a firewall?

A firewall's primary purpose is to act as a security barrier between a network or device and potentially harmful external threats. It filters incoming and outgoing network traffic based on predefined security rules to protect against unauthorized access, cyberattacks, and malware.

How does a firewall work to protect my computer or network?

Firewalls work by examining data packets traveling between your network and the internet. They analyze these packets against a set of predefined rules, allowing safe data to pass while blocking or logging potentially harmful traffic. This process helps prevent unauthorized access and cyber threats.

What are the different types of firewalls, and how do they differ?

There are several types of firewalls, including hardware firewalls, software firewalls, and cloud-based firewalls. Hardware firewalls protect an entire network, software firewalls are installed on individual devices, and cloud-based firewalls provide protection in the cloud environment. Their choice depends on specific security needs.

Are firewalls only for businesses, or should individuals also use them?

Firewalls are essential for both businesses and individuals. Businesses use them to protect their networks, data, and customer information. Individuals can benefit from personal firewall software to secure their computers and devices from online threats, making them a crucial part of online security.

What are some best practices for configuring and maintaining a firewall?

To ensure the effectiveness of a firewall, it's essential to keep it updated with the latest security patches and regularly review and refine its rules. Additionally, configuring the firewall to block unnecessary ports and services and enabling logging for analysis can enhance security.

About the Author
Anshuman Singh
Senior Executive - Content

Anshuman Singh is an accomplished content writer with over three years of experience specializing in cybersecurity, cloud computing, networking, and software testing. Known for his clear, concise, and informative wr... Read Full Bio