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  • Writer's pictureMichael Paulyn

A Comprehensive Overview of Types of Firewalls and Their Functionalities: Part 1

Updated: Feb 17

While the cybersecurity landscape continues to evolve and change, the need for education on fundamental concepts and tools is becoming evermore crucial. One of these tools, firewalls, is essential for helping to safeguard networks against myriad threats.

As the first line of defense, firewalls filter incoming and outgoing network traffic based on a list of predetermined security rules. This blog examines the types of firewalls, their unique capabilities, and the significance each provides when helping to fortify network security.

What are Firewalls?

As an essential network security component, firewalls protect a computer system by filtering out and restricting unauthorized access and malicious activities. At a basic level, firewalls are barriers that dictate which connections and data packets can pass through the firewall and which aren't permitted, preventing unauthorized access, data breaches, and cyberattacks.

4 Types of Firewalls

Firewalls are the first line of defense against online threats in this dynamic, ever-changing cybersecurity landscape. Below are the four main types of firewalls and a breakdown of how they help restrict unauthorized access and sophisticated threats.

1.    Packet Filtering Firewalls

Packet filtering firewalls use the OSI model's network layer (Layer 3) to analyze and scrutinize specific data that pass through the firewall. This type of firewall evaluates the packet header information, including source and destination IP address, port numbers, and protocol types, then runs them against predefined rules.

After the packet is verified to match the specified criteria, the packet can then continue or be blocked. Packet filtering firewalls are some of the most efficient firewalls, which are highly suited for essential network protection. Still, they can't inspect packet contents beyond the header information.

2.    Stateful Inspection Firewalls

Stateful inspection firewalls, or dynamic packet filtering firewalls, provide enhanced security by monitoring the state of active established connections. This capability makes it possible for these types of firewalls to make informed decisions when considering the context of network traffic.

3.    Proxy Firewalls

Proxy firewalls, called application-level gateways, function at the OSI model's application layer (Layer 7). This firewall type works as a middleman between client devices and external servers. For example, when a client requests to access a specific server or resource, the proxy firewall will intercept the request and then begin a separate connection with the destination server on behalf of the client.

This process helps to hide the client's IP address and protects the network's resources from potential attacks from malicious actors. With a more granular protection control, proxy firewalls can quickly inspect, filter, and modify inbound and outbound traffic as needed.

4.    Next-Generation Firewalls (NGFW)

Next-generation firewalls (NGFW) seamlessly blend traditional firewall functionalities with more advanced security capabilities, including intrusion detection and prevention, app awareness, and deep packet inspection. This type of firewall is perfectly designed for fighting modern cyber threats, such as malware, ransomware, and advanced persistent threats (APTs).

The part that makes NGFWs so unique is that they leverage sophisticated techniques that work to analyze network traffic at multiple OSI model layers, making it possible for companies to enforce a more granular take on cybersecurity and mitigate potential attacks.

Final Thoughts

As a pivotal component for safeguarding networks, firewalls are essential when combatting evolving cyber threats. The following best tool is education regarding what firewalls are and their specific types and unique functionalities, which can help ensure the safeguarding of sensitive data and maintaining the integrity of network infrastructures in today's digital landscape.

Hungry for more? Join me each week, where I'll break down complex topics and dissect the latest news within the cybersecurity industry and blockchain ecosystem, simplifying the tech world. 



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