8 Types of Firewalls to Protect Your Computer Network

What is a firewall? It is a cybersecurity tool used to filter traffic on a network. The main purpose of a firewall is to block potentially harmful or threatening traffic and data packets, while allowing legitimate traffic to pass through.

Firewalls can be software, hardware, or cloud-based, with each type having its advantages and disadvantages. Computers, especially those connected to a network, are vulnerable to being hacked. Therefore, a computer must have a network protector called a firewall, especially if it is a company or business computer that is full of important data.

Choosing the right firewall can be a challenge as there are many types of firewalls. Each firewall has different features and configuration methods, so you need to know which type is most needed for your computer.

Firewall types can be divided into several different categories based on their general structure and operating method. Here are 8 types of firewalls that we have compiled for you.

Packet-Filtering Firewall

Packet-Filtering Firewall is a mechanism that can block network data packets based on rules set beforehand by the user. With this security technology, data packets are sorted between those that can enter and those that will be blocked.

Suspicious network traffic such as unknown IP addresses, strange TCP/UDP numbers, and dangerous applications according to the program will be blocked by the Filter Firewall. Actually, this Filtering feature is already a basic feature of every OS such as Linux and Windows.

Since this is the oldest or first type of firewall, its operation is the simplest. The firewall will examine the data packets flowing through the traffic router or traffic switch. It will check packet types, port numbers, IP addresses (destination and origin), and surface-level information without opening the packet data. If the packet does not pass the firewall inspection, it will be rejected and discarded.

The advantage of Packet-Filtering Firewall is that it does not require a lot of resources, which means it does not have a big impact on your computer's performance. Its disadvantage is that it is less accurate compared to modern firewalls whose technology is definitely more advanced.

Circuit-Level Gateway

Circuit-Level Gateway is another simple type of firewall intended for quick and easy work in approving or rejecting traffic without using significant computing resources.

The main function of this firewall is to verify the Transmission Control Protocol (TCP). The TCP handshake check (the TCP connection establishment process) is designed to ensure that the session from the packet is valid.

Although it is very resource-saving, this firewall does not check incoming and outgoing packets. So, if there is a packet containing malware but has the correct TCP handshake, the packet will pass. This is why Circuit-Level Gateway is not sufficient to protect a computer used for business.

Stateful Inspection Firewall

Stateful Inspection Firewall is a network that tracks the condition, characteristics, and operation of the network. This type of firewall is configured to differentiate between "good" network packets that are suitable for various types of connections.

This firewall combines packet inspection technology and TCP handshake verification to create a higher level of protection than when you do not use it.

However, this type of firewall puts more pressure on computing resources. Therefore, it can slow down the transfer of legitimate packets compared to other firewalls.

Proxy Firewall

Proxy Firewall is actually the same as Application-Level Gateway or Cloud Firewall. A proxy firewall operates at the application layer to filter incoming traffic between your network and the traffic source. Therefore, it is called an Application-Level Gateway.

This firewall is deployed through cloud-based solutions or other proxy devices. It does not allow traffic to connect directly, but rather, the proxy firewall first makes a connection to the traffic source and checks the incoming data packets, so they are thoroughly filtered.

In short, a Proxy Firewall creates an extra layer of separation between the client (the system where the data packets originate) and each device on your network, providing additional protection for your network anonymously.

One drawback of a proxy firewall is that it can significantly slow down computer networks because of the additional steps in the data packet transmission process.

Next-Generation Firewall

As the name suggests, the Next-Generation Firewall (NGFW) is a new firewall product that has recently been released. Some common features of the new generation firewall architecture include packet inspection (checking the actual content of data packets), TCP handshake inspection, and surface-level packet inspection. So far, it works the same way as a proxy firewall.

The difference is that the NGFW can include other technologies, such as intrusion prevention systems (IPS), which function to automatically stop attacks on your network. It detects problems automatically and immediately fixes them.

The problem is that there is actually no "new generation firewall" product. This is just a marketing term used by manufacturers. Therefore, you should carefully examine the specifications of the firewall you choose before investing in it.

Software Firewall

Next, there is the Software Firewall. Often mistaken for antivirus software, this is a Software Firewall. It makes sense if people mistake the two, as both the firewall and antivirus are mechanisms that provide security to a system.

The difference is that the firewall helps control network traffic within the system by acting as a barrier (filter) for incoming traffic. Antivirus, on the other hand, protects the system against internal attacks by searching for and removing harmful files and viruses.

In essence, both firewalls and antivirus software are part of cyber security that will protect the system. The main difference is only in the way they operate and work.

A software firewall includes all types of firewalls installed on devices. The benefit of this type of firewall is that it is very useful for creating depth of defense by isolating each endpoint of the network from two directions. The downside is that maintaining individual software firewalls on different devices can be difficult and time-consuming.

Moreover, not every device on the network is compatible with a single software firewall, so you may need to use different firewall software for each computer.

Hardware Firewall

Earlier, there was the Software Firewall, and now there is the Hardware Firewall. This type of firewall uses physical tools that operate in a similar way to traffic routers. Its operation intercepts data packets and traffic requests before they connect to the network server.

Hardware-based firewalls excel at perimeter security by ensuring that dangerous traffic from outside the network is stopped before your network endpoints are exposed to risks.

However, the main weakness of hardware-based firewalls is that they are vulnerable to "insider attacks." Additionally, it should be noted that the capabilities of each hardware firewall vary depending on the manufacturer. Some may have more limited capacity to handle concurrent connections than others. Therefore, make sure you choose a Hardware Firewall from a recommended brand and type.

Cloud Firewall

Finally, there is the Cloud Firewall or Firewall-as-a-Service (FaaS). This type of firewall is considered the same as the Proxy Firewall, as cloud servers are often used in proxy firewall setups. However, in reality, a proxy doesn't always have to be in the cloud.

The benefit of a cloud-based firewall is that it is very easy to add or reduce. When your needs increase, you can add additional capacity to cloud servers to filter larger traffic loads. So, like the Hardware Firewall, this Cloud Firewall excels in perimeter security.

After learning about the different types of firewalls, which firewall architecture is most suitable for your needs? You need to review this for personal computers or for businesses. Then, roughly determine which network load is most suitable. Hopefully, this article helps.