What is a firewall?

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What is a firewall and how does it work?

Networks at home, in the office, or in public all need protection from unwanted traffic, including hackers. With open access to a network, a threat actor could potentially gain control of a computer, steal, corrupt, or delete data, crash systems, or initiate a cyber attack like a Man-in-the-Middle (MitM) attack.

This is where a firewall comes in. Despite being decades old, the technology is considered your first line of network defense. So, what is a firewall in computer network security and what does a firewall do exactly? Let’s find out.

Firewall Definition: What is a firewall in a computer network?

Here is a quick definition of firewall technology in computing: A firewall is a network security system that monitors incoming and outgoing data packets, utilizing a predetermined but modifiable set of rules to block unwanted traffic in, out, or even within a network. A firewall can be software, hardware, on-the-cloud, or software as a service (SaaS). It certainly goes a long way to boost your network privacy than your browser incognito mode feature!

How does a firewall work?

In networking, ports are virtual spaces for computers where network connections initiate. Computers use these entry points to manage and organize network traffic. A firewall helps secure ports by leveraging pre-set rules to scrutinize and filter incoming traffic.

What does a firewall do?

A firewall is like a border guard between a computer and a network, like a local area network (LAN) or the Internet. It secures network connections by only welcoming traffic from accepted IP addresses or sources. The goal of a firewall is to stop unauthorized network activity, including malicious software attacks.

What is the purpose of a firewall & what is a firewall used for?

Now that you know how a firewall works and what it does, you may want to know the purpose of a firewall in cybersecurity.

1. Malware protection

A firewall isn’t an anti-malware tool — a basic firewall can’t remediate or hunt different kinds of malware. However, a firewall can prevent unauthorized parties that intend to drop malware on your system from accessing your computer.

2. Restrict access

A firewall is like your network’s concierge and security system, stopping all undesired traffic, from hacks to viruses. Deactivating your firewall is like removing all security in a condominium building. Access to all apartments is now unrestricted, and the risk of an undesirable event has gone up.

3. Data security

Without a firewall protecting your network, a threat actor could delete or steal your data. Using your data, they can commit blackmail, financial fraud, or identity theft. They can also leverage your data to attack your contacts.

4. Network stability

Theoretically, a hacker interested in mischief could access a network without a firewall and initiate a network crash. Such a crash can cost you money, time, and peace of mind.

5. Threat intelligence

In addition to monitoring incoming and outgoing traffic, a firewall can offer critical insights such as the time and frequency of a cyber attack. Organizations can use this threat intelligence to harden their defense measures.

6. Manage Internet usage

An administrator can set a firewall to shape traffic policy and limit bandwidth for websites. They can also minimize the bandwidth for media streaming.

Organizations can utilize these tools to ensure employees avoid certain websites and media files on company systems. Similarly, parents can use firewalls to protect their children from unsafe content.

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How to set up a firewall

Windows 10

1.      Select Start.

2.      Open the Settings app.

3.      Open Update & Security.

4.      Select Windows Security.

5.      Select Open Windows Security.

6.      Select Firewall & network protection.

7.      Select Domain network, Private network, or Public network.

8.      Toggle settings to On under Microsoft Defender Firewall.

Windows 11

1.      Select Start.

2.      Open the Settings app.

3.      Select Windows Security under Privacy & Security.

4.      Select Open Windows Security.

5.      Select Firewall & network protection.

6.      Select Domain network, Private network, or Public network.

7.      Toggle settings to On under Microsoft Defender Firewall.


1.      Choose the Apple menu.

2.      Go to System Preferences.

3.      Select Security & Privacy.

4.      Select Firewall.

5.      Unlock the preference pane.

6.      Select Turn On Firewall.


1.      Enter your router’s configuration page by entering its internal IP address in a browser.

2.      Find the Firewall tab.

3.      Select On or Enable.

4.      Select Save.

5.      Select Apply.

6.      Your router may need to restart.

Different types of firewalls explained

Software firewalls

Software firewalls inspect data packets that move in and out of computers. Data packets that match known threats are blocked. The most common software firewalls are found on operating systems like Windows and macOS. They’re typically installed on a computer or server to offer basic network security.

Hardware firewalls

A hardware firewall is a physical network security solution that can offer standalone protection to multiple devices. Hardware firewalls fit between a computer and the uplink.

While a software firewall is installed on a machine, a hardware firewall runs from a physical device. A router’s firewall is an example of a hardware firewall, and an operating system firewall is an example of a software firewall.

There are many benefits to using a hardware firewall over a software firewall. Hardware firewalls offer tighter and more consistent security because they use dedicated hardware to shield multiple systems. Hardware firewalls also offer improved threat intelligence and visibility because they run from a centralized system that an organization can access to view multiple devices. Additionally, a hardware firewall can improve performance because it uses its own resources.

Cloud firewalls

A cloud firewall is a software firewall that provides cloud-delivered security to networks. The biggest advantage of using a cloud firewall over a hardware or software firewall is that they’re still operational after a local disaster. For example, while a cyberattack, extreme weather, or employee error may deactivate a hardware or software firewall, a cloud firewall is immune to local issues as it runs remotely. 

Cloud firewalls can also be easier to deploy and are scalable, matching with increasing or decreasing bandwidth. Modern cloud firewalls can also be pretty sophisticated, filtering traffic in various ways to suit a user’s needs.

Human firewalls: What is a human firewall

Human firewalling is an interesting concept that’s not based on any technology. Human firewalling is when employees go through multi-step training to mitigate the risk of data breaches through the following practices:

  1. Identifying security risks.
  2. Reporting suspicious activity.
  3. Remediating cybersecurity loopholes.

Businesses that invest in human firewalling set strong security policies, educate their employees, and find engaging ways to remind employees of best practices. Of course, a human firewall never functions alone. Organizations also invest in actual firewalls, data loss prevention mechanisms, and top threat detection and response tools.

NAT firewalls: What is a NAT firewall

A NAT firewall protects privacy by letting multiple computers access the Internet with a single IP address while their own IP addresses remain hidden. Threat actors surveying networks for IP addresses to gain intelligence may not find specific IP addresses behind a NAT firewall.

Web application firewalls (WAF): What is a web application firewall?

A WAF is a type of firewall that shields web apps by monitoring and filtering any malicious incoming Hypertext Transfer Protocol (HTTP) traffic. It also stops sensitive data from going out of the web app. A WAF protects against widespread web application attacks like SQL injectioncross-site scripting (XSS), and more.

Stateful firewalls: What is a stateful firewall

Stateful firewalls are conventional firewalls that inspect state, port, and protocol to block or allow traffic. Unlike basic firewalls, stateful firewalls can inspect packet data for malicious code. Although these firewalls offer added security, they can be more expensive and resource-hungry.

Next-generation firewalls: What is a next-generation firewall (NGFW)?

NGFW technology offers more defense than basic and even stateful firewalls. In a nutshell, a next-generation firewall combines packet inspection, stateful inspection, and other technologies and systems, such as integrated intrusion prevention systems, upgrade paths, and URL filtering, to offer more comprehensive protection. NGFW technology is usually less cost-effective than standard firewalls.

A more advanced type of NGFW also provides threat detection and remediation. It can complete security assessments, react to threats, recognize suspicious activity, and make it easier for administrators to protect an entire environment with unified policies.

Network firewalls: What is a network firewall?

A conventional firewall is sometimes called a network firewall. The network firewall definition remains the same: a security system that shields computers from unsolicited network traffic.

Proxy firewalls: What is a proxy firewall?

A proxy firewall, also known as a gateway firewall, functions as a gateway between networks for one application. Typical proxy firewalls filter messages at the application layer to shield network resources. Experts say that proxy firewalls are quite secure because they stop networks from contacting systems directly. .

The importance of firewall protection for individuals and businesses

Individuals and organizations need firewalls to prevent hackers from taking control of their systems, stealing data, or dropping malicious software. Individuals and businesses can also use firewalls to block content, control bandwidth, and much more. In a nutshell, not having a firewall is like leaving the door to your house open.

Firewalls vs VPNs

Firewalls aren’t a complete cybersecurity solution. Home users continue to need threat-hunting tools like the latest anti-malware software, while large organizations require MDR security. Users with network security concerns also need a VPN for privacy on networks.

So, what is VPN protection, and how does it differ from a firewall?

A firewall and a VPN are both essential network security tools that act as digital middlemen between computers and the Internet. But that’s where the similarities end. While a firewall is a network barrier that polices incoming and outgoing traffic, a VPN encrypts your data and conceals your IP address while assigning you a virtual one.

Users who demand network security and privacy use a firewall and a VPN together. The firewall blocks unauthorized network access by managing communications with content filtering, and the VPN encrypts communication and shields users, especially on untrustworthy networks like public wireless connections.

How to choose the best firewall for your business?


Firewalls can vary in pricing with their sophistication. Choose a firewall that matches your

business’s budget.

Number of users:

Firewalls have capacities. A small business firewall may protect up to 50 users, while an

enterprise-class firewall may shield thousands of devices. Select a firewall that suits the size of

your organization.


As a small business without an IT department, you be better off with a software firewall as it’s

simpler to install. However, software firewalls can require more upkeep. Pick a hardware firewall

if you have a competent tech team that can configure the tool correctly.


A cloud-based firewall can be a more advanced and convenient option than a software or

hardware firewall. Cloud-based options are also easier to deploy and scalable. If your business

is rapidly expanding, then consider using a cloud-based firewall. However, such firewalls can be


The future of firewalls

Firewalls are one of the oldest cybersecurity measures, shielding networks for over 25 years. They remain an essential first line of defence, defending networks from unwanted traffic from external networks like the Internet.

Like many cybersecurity technologies, firewalls have evolved to suit today’s environment. While basic firewalls exist for home users, advanced firewalls serve more demanding concerns. Different types of firewalls are available as software, hardware, on the cloud, and SaaS to match an organization’s cybersecurity requirements.

As long as networks exist, demand for firewalls will remain. And as long as threat actors advance and develop more complex attacks, firewalls will continue to grow to offer a higher level of network security.

Featured Resources

Firewall FAQs

Does my business need a firewall?

Without a firewall, your company is unintentionally letting hackers access important data. While software firewalls safeguard systems by preventing threats and harmful network traffic from entering the network, the hardware alternative prevents suspicious data from entering your company’s network.

What are 3 types of firewalls?

The 3 types of firewalls, include hardware firewalls, software firewalls, and cloud firewalls. What is a firewall on a computer?

What is a firewall on a computer?

A firewall is a network security system that monitors incoming and outgoing data packets and employs a predetermined set of rules to prevent undesired traffic from entering, leaving, or even entering a network.