What are Firewalls? Here's the Complete Explanation

What are Firewalls? Here's the Complete Explanation

What are Firewalls? Here's the Complete Explanation

 A case study says that on average, hackers infiltrate an unsuspecting user's computer every 39 seconds. As cyber crime continues to increase. Protecting your sensitive data is what you should do using a firewall is the first line of defense. So, in this article, we will discuss what a firewall is in full.

What are Firewalls?

A firewall is a system of software or hardware designed to prevent unauthorized access to an individual computer or computer network. They are mostly used as the first line of defense to protect your device or network from online threats such as hackers, viruses, Trojans and worms.

Every time you connect to the Internet, your computer is exposed to all kinds of malicious programs and bad people looking to infiltrate your computer to steal your personal information, send spam emails to your inbox, or use your computer to launch attacks against other people.

A good firewall system deters attackers from trying to infiltrate your system and prevents your data and information from flowing to criminals.

How Do Firewalls Work?

Firewalls carefully analyze incoming traffic based on predefined rules and filter traffic coming from unsafe or suspicious sources to prevent attacks. Firewalls protect traffic at computer entry points, called ports, where information is exchanged with external devices. For example, “Source address is allowed to reach destination over port 22.”

Think of the IP address as the house, and the port number as the rooms in the house. Only trusted people (source address) may enter the home (destination address). Then filtered again so that people in the house are only allowed to access certain rooms (destination port) and it depends on the owner. Suppose the owner is allowed into any room (any port), while children and guests are allowed into a certain set of rooms (certain port).

So a firewall acts like a traffic guard at your computer's entry point, or port. Only trusted sources, or IP addresses, are allowed in. IP addresses are important because they identify a computer or resource.

Firewall Types

Firewall types can be divided into different categories based on their general structure and method of operation. Here are some types of firewalls:

* Packet-Filtering Firewall

* Circuit-Level Gateways

* Stateful Inspection Firewall

* Application-Level Gateway (Proxy Firewall)

* Network Address Translation (NAT) Firewalls

* Next-Gen Firewalls

* Software Firewalls

*Hardware Firewalls

How do these types of firewalls work? Here are some brief explanations:

Packet Filtering Firewall

Packet-Filtering firewall is a management program that can block network traffic IP protocols, IP addresses, and port numbers. This type of firewall is the most basic form of protection and is meant for smaller networks.

While packet-filtering firewalls can be helpful, they also have limitations. Since all web traffic is allowed, it does not block web based attacks. So, you need additional protection to differentiate between friendly and malicious web traffic.

Circuit-Level Gateways

A Circuit-Level Gateway is a type of firewall that functions by verifying the transmission control protocol (TCP) handshake. This TCP handshake check is designed to ensure that the packet's session is valid.

While very resource efficient, this firewall doesn't check the packet itself. So if a packet contains malware, but has the proper TCP handshake, it will pass.

Stateful Inspection Firewall

Stateful Inspection firewall combines packet inspection technology and TCP handshake verification. It offers better security than packet-filtering or circuit-level.

But unfortunately this type of firewall places a greater burden on network performance. Which can slow down legitimate packet transfers.

Application-level Gateway (Proxy Firewall)

Firewall proxies filter incoming traffic between your network and traffic sources at the application level hence, the name “Application-Level Gateway”. Unlike a basic firewall, a proxy acts as an intermediary between two end systems. The client must send a request to the firewall, which is then evaluated against a set of security rules and then either allowed or blocked.

Most importantly, proxy firewalls monitor traffic for layer 7 protocols such as HTTP and FTP, and use stateful and deep packet inspection to detect malicious traffic. But there is one drawback to these proxy firewalls, namely they can create significant slowdowns due to the extra steps in the process of sending data packets.

Network Address Translation (NAT) Firewalls

Network Address Translation (NAT) Firewalls allow multiple devices with independent network addresses to connect to the internet using a single IP address, hiding each other's IP address.

As a result, attackers scanning the network for IP addresses are unable to capture specific details, providing greater security against attacks. A NAT firewall is similar to a proxy firewall in that it acts as an intermediary between a group of computers and outside traffic.

Next-Gen Firewalls

Next-Gen firewalls are more sophisticated than packet-filtering and stateful firewalls. Why? They have more levels of security, going beyond standard packet filtering to check the entire packet.

Next-Gen firewall combines traditional firewall technology with additional functionality, such as encrypted traffic inspection, intrusion prevention system, anti-virus, and more. Primarily, it includes deep packet inspection (DPI).

While basic firewalls only look at packet headers, deep packet inspection examines the data within the packets themselves, enabling users to more effectively identify, classify, or terminate packets with harmful data.

Firewall Software

Software firewall includes any type of firewall that is installed on a local device rather than a separate piece of hardware (or cloud server). The great benefit of software firewalls is that they are very useful for creating defenses in depth by isolating individual network endpoints from one another.

However, maintaining individual software firewalls on different devices can be difficult and time consuming. In addition, not every device on the network may be compatible with a single firewall software, which may mean having to use several different firewall software to cover each asset.

Hardware Firewalls

Hardware firewalls use physical devices that act in a manner similar to traffic routers to intercept data packets and traffic requests before they connect to network servers. Physical appliance-based firewalls like these excel at perimeter security by ensuring malicious traffic from outside the network is intercepted before enterprise network endpoints are exposed to risk.

However, the main drawback of hardware-based firewalls is that it is easy for insider attacks to get through. Also, the actual capabilities of a hardware firewall may vary depending on the manufacturer.

The Risks of Not Using a Firewall

You may already be engaging in safe computer and internet use practices, including the following:

* You don't click on unknown links or attachments.

* You only log on to trustworthy and known websites.

* You never provide any personal information unless absolutely necessary.

* You have a strong, unique and complex password for each online account that you update frequently.

Does that keep you guys safe enough? The answer is probably "no." If you use the internet, it is a good idea to have an active firewall on your computer. Cyber threats are widespread and growing. It is important to use the defenses available to help protect your network, and the personal information stored on your computer, against cybercrime. Here are the three main risks of not having a firewall:

Open Access

Without a firewall, you accept every connection to your network from anyone. You will have no way of detecting incoming threats. It can make your device vulnerable to malicious users.

Lost Or Interrupted Data

Not having a firewall can leave your device open, which can allow someone to gain control over your computer or network. Cyber criminals can delete your data. Or they can use it to commit identity theft or financial fraud.

Network Jam

Without a firewall, attackers can shut down your network. Running it again, and trying to recover stored data, can involve your time and money.

Firewalls are an important part of security technology, especially when different types of firewalls work together to provide protection. Firewalls can help keep your network, computers and data safe and secure.


So What Are Firewalls? A firewall is a type of cybersecurity tool used to filter traffic on a network. The way a firewall works is basically, it checks all data trying to pass it along to determine whether to pass it to its destination. Firewalls are also one of the many solutions available in today's cybersecurity world to control external threats.

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So many articles What is a Firewall. Look forward to other interesting articles and don't forget to share this article with your friends. Thank you…

Resa Risyan

Just an ordinary person who wants to share a little knowledge, hopefully the knowledge I provide can be useful for all of us. Keep in mind! Useful knowledge is an investment in the afterlife.

Also, read the article about What Is Frame Rate In Video And How Is It Affected?. And see you in another article. Bye
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