Firewall Types: The 3 Digital Barriers to Know (2023)

By Tibor Moes / Updated: June 2023

Firewall Types: The 3 Digital Barriers to Know (2023)<br />

Firewall Types

Imagine your computer as a busy airport, and data packets are the passengers flying in and out. Now, consider a firewall as your strict airport security — scanning passports, checking for threats, and only allowing legitimate passengers to board. It’s this firewall that keeps your digital airport running smoothly, and free from harm.


A firewall is a security system that monitors and controls incoming and outgoing network traffic based on predetermined rules, acting like a digital gatekeeper to protect your computer or network from harmful or unauthorized access.

Type 1 – Next-Generation Firewalls (NGFWs): Unlike their traditional counterparts, NGFWs don’t just filter traffic based on ports and protocols. They go a level deeper, inspecting packets for malicious content and keeping a keen eye on the application level. This means they can identify and block sophisticated attacks more effectively.

Type 2 – Proxy Firewalls: The digital equivalent of a middleman, a proxy firewall intercepts all traffic incoming and outgoing from a network. Acting as the go-between, it hides the true network addresses and provides an additional layer of protection against threats from the outside.

Type 3 – Stateful Inspection Firewalls: These are like keen detectives, not just checking IDs, but also remembering past interactions. They monitor the state of active connections and use this context to assess the legitimacy of network packets. This way, they keep a continuous check, ensuring ongoing safety.

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Firewall Types In-depth

Next-Generation Firewalls (NGFWs)

Remember when we talked about the bouncer at your home party, scanning invitations and ensuring only the right people got in? Well, think of Next-Generation Firewalls as the bouncer who has a sixth sense. They’re not just looking at the invitation — they’re peering into the soul of each guest, making sure no one is hiding anything fishy under their friendly facade.

Let’s get into the nitty-gritty of what makes Next-Generation Firewalls (NGFWs) so special and why they’re considered the superheroes of the digital security world.

NGFWs are like your traditional firewalls, but with an added dash of cleverness. While traditional firewalls focus on the basics — like checking the data packets’ source, destination, and type — NGFWs are Sherlock Holmes in the digital world, digging deeper and gathering more clues.

How do they do this? By performing what’s known as ‘deep packet inspection’. This might sound like tech jargon, but it’s actually a bit like reading a book instead of just judging it by its cover. NGFWs examine the contents of data packets, not just their labels, ensuring that nothing harmful is hidden within.

Think about it like this: if data packets were envelopes, traditional firewalls would only read the address. NGFWs, on the other hand, open the envelopes and read the letters inside to ensure everything’s above board.

But there’s more! NGFWs also keep an eye on the application level. In our party analogy, it’s like understanding not only who the guests are but also what kind of conversations they’re having. If anyone starts talking about causing trouble, the NGFWs will show them the door!

NGFWs can also identify and control applications, even if the applications are trying to sneak through in disguise, hidden within other traffic. They’re even savvy enough to manage evolving threats, such as new viruses and more sophisticated types of hacking.

The beauty of NGFWs is that they offer a more detailed, rigorous, and flexible approach to security. They adapt and learn, meaning they’re not only great at handling the threats we know about today but also the ones that could crop up tomorrow.

In a nutshell, Next-Generation Firewalls are the vigilant, smart bouncers of the digital world — always keeping an eye out and going the extra mile to ensure our computers and networks stay safe and sound.

Proxy Firewalls

Imagine you’re buying a gift for a friend. Instead of going directly to the store, you send a trusted buddy to pick it up and deliver it. Now, the store doesn’t know you bought the gift — it only knows your buddy. That’s essentially how proxy firewalls work: they act as the “trusted buddy” for your computer’s network.

Proxy Firewalls play the part of a middleman, or a liaison, in your digital world. They stand between your network and the big wide world of the internet, intercepting everything that comes in or goes out. By doing this, they protect the network by keeping its true identity — its IP address — hidden from prying eyes.

To understand this better, let’s think about the post office. Imagine sending a letter. You drop it off at the post office, and they handle the delivery, right? Proxy firewalls work in a similar way. When you want to send a request out onto the internet — maybe you want to visit a webpage or send an email — your request first goes to the proxy firewall.

Just like the postal worker, the proxy firewall takes your request, checks it over, and then sends it out to its destination. The firewall’s address is used, not yours, protecting your network’s identity.

But it works the other way around too! When data tries to enter your network from the internet, it first arrives at the proxy firewall. The firewall checks it out, makes sure it’s safe, and then sends it to the right place within your network.

Now, why does all this matter? Well, by acting as a go-between, the proxy firewall provides an additional layer of security. It makes sure that all communications are safe and above board before they reach your network. It also helps to keep your network anonymous, which is another excellent way to ward off potential attackers.

The whole process might sound a bit lengthy, but rest assured, it happens faster than the blink of an eye. Just like our trusted buddy delivering the gift, the proxy firewall is swift, efficient, and always has your network’s safety as its top priority.

In essence, Proxy Firewalls are the clever, dependable friends in the world of digital security, always ready to lend a hand and ensure your network’s interactions are safe and private. It’s thanks to them that we can browse the internet with a little more peace of mind.

Stateful Inspection Firewalls

Picture this: you’re at a train station with an eagle-eyed station master who not only checks tickets but also remembers every passenger’s face, their destination, and their purpose of travel. This station master is very much like a Stateful Inspection Firewall – always on the ball, never forgetting a detail.

Stateful Inspection Firewalls, often just called stateful firewalls, have a very particular set of skills. They don’t just examine data packets as they come and go. Oh, no. They remember. They create and keep track of what we call a “state table”, a record of all active connections at any given time.

Now, let’s make this easier to understand. Suppose you’re at a busy concert. The bouncer at the gate is the stateful firewall. He checks your ticket when you first enter – this is when the connection is established. But he doesn’t just forget about you. He keeps an eye on you and every other guest during the whole concert. If he sees you trying to sneak backstage or cause a commotion, he’ll step in.

Stateful firewalls operate similarly. They look at every single data packet that passes through your network, checking where it’s from, where it’s going, and what it wants to do when it gets there. If the packet’s behaviour matches an existing, approved connection in the state table, the firewall lets it through. But if it deviates or does anything unusual, the firewall steps in.

The real magic here is that stateful firewalls can identify and adapt to various types of connections and a range of networking protocols. Whether data packets are part of an ongoing conversation, just saying hello, or waving goodbye, the stateful firewall understands the context.

One of the big benefits of stateful firewalls is their efficiency. By remembering the state of each connection, they can process packets more quickly and keep your network running smoothly. They’re also adept at blocking unauthorized access and defending against certain types of attacks that other firewalls might not catch.

So, in the grand concert that is your network, a Stateful Inspection Firewall is the ever-watchful bouncer, always keeping track and ensuring only the right data packets get to party. It’s this impressive memory and the ability to understand context that makes them such a powerful tool in the fight for digital security.


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How to stay safe online:

  • Practice Strong Password Hygiene: Use a unique and complex password for each account. A password manager can help generate and store them. In addition, enable two-factor authentication (2FA) whenever available.
  • Invest in Your Safety: Buying the best antivirus for Windows 11 is key for your online security. A high-quality antivirus like Norton, McAfee, or Bitdefender will safeguard your PC from various online threats, including malware, ransomware, and spyware.
  • Be Wary of Phishing Attempts: Be cautious when receiving suspicious communications that ask for personal information. Legitimate businesses will never ask for sensitive details via email or text. Before clicking on any links, ensure the sender's authenticity.
  • Stay Informed. We cover a wide range of cybersecurity topics on our blog. And there are several credible sources offering threat reports and recommendations, such as NIST, CISA, FBI, ENISA, Symantec, Verizon, Cisco, Crowdstrike, and many more.

Happy surfing!

Frequently Asked Questions

Below are the most frequently asked questions.

What is the main difference between a traditional firewall and a Next-Generation Firewall (NGFW)?

A traditional firewall primarily checks the source, destination, and type of incoming and outgoing data packets, a bit like checking the address on an envelope. In contrast, a Next-Generation Firewall (NGFW) performs ‘deep packet inspection,’ examining the content of the packets to catch any concealed threats. It’s like opening the envelope and reading the letter inside to ensure nothing harmful is hidden.

Why use a Proxy Firewall if it slows down the internet speed?

While it’s true that a Proxy Firewall may slightly slow down internet speed due to its process of examining and rerouting traffic, the benefits often outweigh this minor downside. Proxy Firewalls offer enhanced security by intercepting all incoming and outgoing traffic, providing an additional layer of protection, and maintaining the anonymity of your network’s IP address.

How does a Stateful Inspection Firewall remember past interactions?

A Stateful Inspection Firewall keeps track of all active connections in a ‘state table.’ It examines each data packet, noting its source, destination, and purpose, and matches this information against the state table. By remembering the state of each connection, the firewall can process packets more efficiently and detect any unusual or suspicious activity.

Author: Tibor Moes

Author: Tibor Moes

Founder & Chief Editor at SoftwareLab

Tibor is a Dutch engineer and entrepreneur. He has tested security software since 2014.

Over the years, he has tested most of the best antivirus software for Windows, Mac, Android, and iOS, as well as many VPN providers.

He uses Norton to protect his devices, CyberGhost for his privacy, and Dashlane for his passwords.

This website is hosted on a Digital Ocean server via Cloudways and is built with DIVI on WordPress.

You can find him on LinkedIn or contact him here.

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