What is Firewall: The Types and the Value of Quality Protection

Even though you may not be an old hand at the Internet, chances are you’ve heard of firewalls. They’re not just some fancy term for online safety, they’re actually one of the most basic means of protecting yourself online. Think of a physical firewall in a building – it stops the fire from spreading. Now a cyber-firewall won’t let those malicious digital agents get into your machine and cause chaos over your network. A network firewall is more or less a security device that you put at the network border – it looks, inspects, and filters out the traffic to keep malicious threats at bay, making sure only the things you actually want are allowed through.

A hardware firewall plays a crucial role in network security, especially for home networks and Internet of Things (IoT) devices. It’s usually integrated into your router, which means you can mostly just switch it on and not have to think about it too much – it will give you some level of protection against potential vulnerabilities in any devices that are connected. Having a firewall in place is pretty much essential for stopping malicious threats getting in by filtering out that unwanted incoming traffic and keeping unwanted visitors from getting in.

Conspiracy

Jan 15, 2026

14 min read

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How firewalls work in network security

A firewall is simply a software that filters your traffic – both in and out. It guards the entry points (ports) of the device you use to surf the web. All the data packets get passed through the firewall, which has got a robust library of threats and rules to go off. It looks at the traffic and either lets it through or blocks it. Firewalls also look at traffic to detect and prevent threats by being on the lookout for anything suspicious that might indicate a problem.

So firewalls catch viruses and other malware, and they repel the hackers’ attacks too. They protect your environment from any unauthorized access, and they block attempts by malicious traffic to get into or leave your network. Firewalls act as a go-between for internal and external networks, and they do this by looking at data packets and filtering out any threats. With the regular updates they get, firewalls are always up to speed with new threats as they come along. You can also choose to allow or disallow access to certain things like domain names, protocols, IP addresses, or even just keywords – that way you make sure that only people you trust can get into your network.

Definition of a Firewall

A firewall is a vital network security device or software program that takes care of monitoring and controlling incoming and outgoing network traffic, based on the security rules that you’ve set. Firewalls act as guardians, protecting your network from all sorts of threats and playing a big part in your overall cybersecurity strategy. They sit between a network that you trust and an external network like the Internet, and they keep those malicious agents out. You can get firewalls that are purely hardware, purely software, or a mix of the two – but whatever type you go for, the thing is, they’re indispensable for protecting computer networks, devices, and data from all the different types of cyber threats out there. By taking a close look at data packets and enforcing the security rules you’ve got in place, firewalls make sure that only legitimate traffic is allowed, so your network is safe and sound.

Importance of Firewalls in Network Security

Firewalls are pretty much a must in the world of network security – they’re the first line of defense against external threats like hackers, malware, and all sorts of other cyber attacks. Choosing the right firewall is critical, because it needs to meet your organization’s security, compliance, and performance needs. By stopping unauthorized access to your network’s resources, firewalls keep your sensitive data safe and make sure that your computer systems and networks stay private and secure. When you combine a firewall with an intrusion prevention system (IPS), you get even better protection against malware and application layer attacks. By carefully managing the traffic in and out of your network, firewalls do a great job of stopping cyber attacks in their tracks, keeping your data safe, and keeping your computer systems and networks secure. Antivirus software works alongside firewalls to detect and get rid of malware, giving you comprehensive protection at the device level.

Types of firewalls for managing network traffic

So, how do firewalls get classified? Well, there are a few ways to group them. You can do it by how they’re installed, or by how they filter traffic.

By installation:

Software firewalls
Hardware firewalls
Cloud firewalls

By filtering:

Packet filtering firewalls
Circuit-level gateways
Stateful inspection firewalls
Application-level gateways (proxy firewalls)
Unified threat management (UTM) firewalls
Next-generation firewalls (NGFW)

Firewall features have come a long way in recent years – they’ve moved on from simple packet filtering to advanced security tools that use deep learning and automation to detect and respond to modern threats.

And then there’s the security access service edge (SASE) concept – that’s a key part of comprehensive cybersecurity solutions for people who work remotely, combining networking and security services to keep data and applications safe.

Now, let’s get down to the nitty-gritty.

Types of firewalls by installation: software firewalls

Software firewalls, or host-based firewalls, are just applications that you install on your device. A software firewall runs on your computer or device, keeping an eye on network traffic and stopping any malicious threats – especially when you’re on the move. Most modern operating systems, desktop and mobile both, come with a built-in firewall, and you can also install extra software to help you out. However, firewalls like this are more or less just good enough for individual use. If you’re trying to protect a whole network, you need something more substantial.* Hardware firewalls are physical devices – a type of thing you can actually see and touch – and installing them on every machine is a bit of a pain. You’ll need to find a spot for them, hook up the wires, and plug them into a power source. It takes more time and effort upfront, but at the end of the day, it’s a solution that’s made for the big leagues. That’s why network firewalls are hardware based.
Cloud firewalls are really taking off these days, as more and more businesses decide to switch things up and make the online jump in pursuit of flexibility and scalability. As a result, cloud firewalls are becoming an integrated part of all these online environments. Their main advantage is that they let you manage traffic a heck of a lot faster and easier.

The choice between software, hardware, and cloud firewalls can have a significant impact on network performance , since each one handles latency, throughput, and overall resource utilization in its own unique way, and all of these factors can add up to make or break your network infrastructure.

Types of firewalls by filtering: stateful inspection firewalls

A packet filtering firewall takes a look at each network packet as it passes through the router, and it decides whether to let it through based on stuff like IP addresses, port numbers and protocols. While it can’t actually take a close look at what’s inside the packet itself, this simple and cost-effective method can at least help keep the bad guys out by filtering traffic at a basic level – which is better than nothing really.
Circuit-level gateways check the source of the data packets – and that’s about it really – they don’t bother to look any deeper. The source needs to have been approved by a successful TCP handshake, but even then, the data packet might still contain some dodgy elements. Honestly, you’re better off not relying solely on a solution like this.
A stateful firewall does everything that the packet filtering firewall can do, plus a whole lot more. It monitors and analyses active connections, keeping tabs on the status of all current network communications. By doing that, the stateful firewall can help make some pretty informed filtering decisions based on the connection state, plus the rules set by the admin.
Application level gateways/proxy firewalls act as an intermediary between internal and external systems – they sit right in the middle and have a look at application-layer traffic in depth. It’s only when the traffic matches the right criteria that the firewall lets it through to the system.
A Unified Threat Management (UTM) firewall is a pretty complex solution that checks the surface-level details of the sender and connection – and then, if that looks okay, it kicks in some of its additional features, like antivirus and intrusion prevention modules.
Next-generation firewall – or NGFW for short – is just what it says on the tin – a new and improved kind of firewall that’s got all the bells and whistles. As well as all the usual options, it should also be able to prevent all sorts of different types of intrusion, block threatening apps, and stay up to date with the latest and greatest protection techniques.

Firewalls, after all, are all about inspecting each network packet in order to enforce security policies and prevent unauthorized access.

Unfortunately, a standard, comprehensive definition of an NGFW firewall doesn’t really exist, but if you do decide to go with a software solution for your system, then chances are you’ll be dealing with a NGFW. So you should probably go and check the official specs, and get to know the capabilities of that particular solution.

If you’re worried about your online safety then you’ll probably want to apply a firewall – and the modern NGFW solutions are the way to go. But you can’t just stop at a firewall – you also need to think about the device itself and the network too. That’s why the combination of hardware and software firewalls is pretty much the default these days – though it’s not the only tool in your arsenal.

Using a VPN as an additional security level will give you its own firewall too. For instance, there’s the popular VeePN provider. As well as masking your IP address and unblocking access to resources, it can also filter connections – so you can adjust the VPN to allow or block specific ports, and VeePN will keep an eye on your internet connection on any device, at any location.

Next-Generation Firewalls (NGFWs)

Next-generation firewalls (NGFWs) are a major step forward in network security devices – offering a much higher level of protection than traditional firewalls. These high-end firewalls combine the capabilities of traditional firewalls with additional extras like intrusion prevention systems (IPS), application awareness, and secure sockets layer (SSL) inspection. They’re designed to provide top-notch security by understanding the context of the traffic, making them an essential part of modern network security strategies.

Features of NGFWs

NGFWs come with a range of features that give them the edge over traditional firewalls, including:

Deep Packet Inspection (DPI): This feature lets NGFWs take a good hard look at the contents of data packets, enabling them to detect and prevent malware.
Application Awareness: NGFWs can spot and control specific applications and protocols, making sure that only authorized applications get through.
Intrusion Prevention Systems (IPS): These systems detect and prevent intrusions – adding an extra layer of security to the mix.
Secure Sockets Layer (SSL) Inspection: By decrypting and taking a look at encrypted traffic, NGFWs can identify and block malicious content hidden within SSL traffic.
Reputation-Based Malware Detection: This feature blocks known malicious sites and IP addresses, stopping you getting to any dodgy resources.
Intent-Based Networking: NgFWs give you safe access to the cloud, so you can be sure your data and apps are secure and reliable – no matter where you’re accessing them from.

Deep Packet Inspection and Application Layer Security

Threats are getting more and more sophisticated and firewalls are having to get smarter to keep up. One of the ways they’re doing that is by adding features that let them really dig in and examine network traffic, and make sure it’s clean before it hits your network. Two of the key technologies that enable this are deep packet inspection (DPI) and application layer security. Used together, they create a robust defense against malicious traffic and unwanted access, making sure every bit of traffic that comes in or out of your network is thoroughly vetted.

Deep Packet Inspection – the nitty gritty

DPI is a really powerful tool that lets firewalls do more than just glance at the surface level of a packet and see where it’s headed. It actually lets them dig into the payload and see what’s really going on in there. This means they can spot malware hiding in plain sight, or data being sent in ways that shouldn’t be happening. Its especially valuable for organisations that have a lot of sensitive data to protect, because it lets them catch threats in real time.

DPI is also super useful for organisations that need to keep strict control over their network traffic, because it lets them block malware and other bad stuff before it even gets to the network. And it’s not just about being a good detective – DPI also helps keep your network traffic flowing smoothly, by making sure that only legitimate packets get through.

Application Layer Security in Firewalls

App layer security takes it up a notch from DPI, by focusing on the actual apps and services that are running on your network. So instead of just blocking traffic based on IP addresses or ports, firewalls using app layer security can get a look at the actual content and behaviour of the traffic. This means they can identify and control traffic from web browsers, email clients, and all the rest.

This kind of inspection is essential for catching the super-sneaky attacks that target specific apps and vulnerabilities. And with app layer security, you can enforce security policies that are tailored to each app, block unwanted or dodgy software, and even do some basic intrusion prevention. It’s a critical layer of defence that helps keep your network and devices safe from a wide range of threats.

Network Address Translation (NAT) and Cloud-Based Firewalls

As more and more of us are working in the cloud, network address translation (NAT) is becoming a really important feature in modern firewalls. NAT lets you have lots of devices on a private network share a single public IP address – making it much easier to manage your network, and also much more secure.

Why Firewalls Use NAT

Firewalls with NAT act like a kind of middleman between your internal network and the outside world. When your devices on a private network want to send traffic out to the world, the firewall takes their private IP addresses and replaces them with the firewall’s own public IP address. And when traffic comes in from the outside, the firewall translates it back to the right internal device. Its a really neat way to keep your internal network hidden from prying eyes, while still letting devices on that network access the internet.

By using NAT, you can stop people trying to get in who shouldn’t be there, and also make sure that sensitive data on your internal network stays safe. NAT also helps out by saving you public IP addresses – so you can scale your network without running into IP address shortages. In cloud environments, NAT makes sure you can get to your cloud apps and services from anywhere, safely and securely.

Firewall Deployment and Management

Getting your firewalls set up and running properly is crucial for keeping your network safe. This means keeping your security settings up to date, and tweaking your firewall rules to make sure they’re doing the most good. Firewalls can be set up in different ways, depending on what you need: network firewalls protect the whole network, host-based firewalls protect individual devices, and virtual firewalls are great for virtual environments. Proper setup is key to making sure your firewalls can really see what’s going on in your network, and keep it safe from threats.

Configuring and Managing Firewall RulesConfiguring and Managing Firewall Rules – The Basics

Getting the right firewall rules up and running is key to keeping unwanted visitors and malicious activity at bay – and that starts with making sure they’re based on your organisation’s security guidelines. To stay on top of it all, keep your rules under review and make any necessary changes – after all, security policies aren’t static things and neither should your firewall rules be.

You can set rules to either let traffic through or block it, all depending on factors like the IP address it’s coming from or where it’s heading, what port number it’s using, and what protocol it’s running on. But here’s the thing: don’t forget about how you handle traffic going out as well as coming in – keeping a lid on that can be just as important for stopping data getting siphoned off or other threats getting a foothold in sensitive areas. By doing things right with your firewall rules, you can have confidence that your network is properly shielded against all the things that could go wrong – and keep your critical resources safe and sound.

Conclusion

New firewall solutions enter the market daily. They offer more functionality, easier and more flexible configurations, and faster operation. There is always a choice and a possibility to protect yourself with the best solution. A virtual private network (VPN) also plays a crucial role in providing secure and encrypted internet connections, complementing the protection offered by firewalls. Or a combination of such.