3 Types of Firewalls and How They Work

When it comes to protecting your computer’s network system, what is the first thing that comes to your mind? Using an antivirus application or program or maybe a managed firewall service provider, right?

3 Types of Firewalls and How They Work

Well, yes, it’s certainly a good choice. But, the way organized cybercrime is increasing, it’ll be impossible for on tinsy-tiny antivirus program to stop everything.

So, what else do you need?

Well, I have been using a firewall system on my computer. And, as of now, it has done a pretty good job. But I am not here to talk about my own experience. Instead, I would focus on the tool itself and how it works. Also, I’d share a little bit of information about the types as well.

So, without any further ado, let’s get started with it.

What is a Firewall System?

A firewall system is a network security device that is designed to monitor and control traffic between different networks, such as the Internet and a corporate network. 

The main purpose of this system is to prevent unauthorized access to or from a private network, while allowing authorized traffic to pass through.

These can be implemented as hardware devices, software programs, or a combination of both. They work by examining the data packets that are sent and received across a network. They can also use a few predefined rules to determine whether or not to allow the traffic to pass through.

Firewalls are configured to block various types of traffic, such as certain protocols or ports, and can also be set up to allow or deny access to specific IP addresses or ranges of addresses. 

In addition to these basic functions, many modern firewalls also include features such as - 

  • Intrusion detection and prevention, 
  • Virtual private network (VPN) support, and 
  • Application-level gateway services.

Now, let’s move on to the next section to get more information about the types of firewalls and how you can use them.

Types of Firewalls

There are various types of firewalls available in the market. However, each of them works quite differently and, therefore, it’s best to know all about them accordingly.

Let’s get started, then. 

1: Packet Filtering Firewall

A packet filtering firewall will operate inclined at a junction point where your router and all of the switches it has work. However, as their name suggests, they don’t route packets.

Instead, they compare the packets received to the established criteria of your system, including - packet type or IP address. So, the modules, which are flagged as troublesome, are dropped by the system unceremoniously. You won’t be able to forward them in any way. 


It’s extremely quick and efficient, when it comes to scanning a boatload of traffic.

The entire traffic you have received can be filtered with a single device.

One of the most inexpensive options available in the market.

It will not affect the other resources, such as network performance, too much.

And it’s quite easy to use too. So, almost anyone can deploy it on their system. However, yes, it doesn’t check the payload of the received data. Therefore, it can be spoofed pretty easily.

2: Circuit-Level Gateway

This type of firewalls tend to monitor TCP handshakes and various other network protocol sesh initiation messages. These can be ideal for taking care of a remote network system. However, it doesn’t offer any application layer monitoring at all. 


It will only process a requested transaction. Everything else will be rejected.

You can set up the system quite easily and manage it perfectly.

It doesn’t require too much money to set up. The end-user experience is pretty good too.

However, the product will require ongoing updates to offer an impeccable security system. And you will have to use them in conjunction with various other systems to get the most out of it.

For example, using it with an application-level gateway can be perfect for you.

3: Application-level Gateway

This type of tool, technically a proxy firewall, functions as a single entry point to your network system. It can inhibit the performance of the network it’s been integrated in. Therefore it can be working slowly or quickly, depending on how quick your network system is.


It can protect your anonymity and ensure that your information doesn’t get revealed.

It usually examines almost all communications between devices and outside sources.

The fine-grained security control offered by it’ll restrict you from opening problematic webpages.

However, it is much costlier than any other firewall option. And, it also doesn’t work well with any network protocol available out there.

FAQs - Frequently Asked Questions

Q: What are some common features of a next-generation firewall?

A: Common features of a next-generation firewall include intrusion prevention, application awareness, user identification, and integration with threat intelligence feeds.

Q: Can firewalls prevent all types of cyber attacks?

A: No, firewalls cannot prevent all types of cyber attacks, but they can provide a critical layer of defense against many types of threats.

Q: How do firewalls help to protect against malware?

A: Firewalls can help to protect against malware by blocking traffic to known malicious IP addresses and domains and by inspecting data packets for suspicious content.

Q: Can firewalls be bypassed?

A: Yes, firewalls can be bypassed through various methods, such as using encrypted traffic, exploiting vulnerabilities in the firewall software, or using social engineering tactics to trick users into downloading malware.

Q: What are some best practices for configuring a firewall?

A: Best practices for configuring a firewall include defining a strong security policy, limiting access to only necessary services, updating firewall software regularly, and monitoring firewall logs for suspicious activity.

Q: Can firewalls affect network performance?

A: Yes, firewalls can affect network performance, especially if they are improperly configured or if they are performing resource-intensive tasks such as deep packet inspection.

Q: Are hardware firewalls more secure than software firewalls?

A: Hardware firewalls can be more secure than software firewalls because they are separate devices that are not vulnerable to software-based attacks. However, the security of a firewall depends more on its configuration and management than its hardware or software.