5 Types of Firewalls: Which One Do You Need?

The Firewall's Evolution

Modern firewalls span a wide range of technologies, each with distinct inspection methods, security features, and deployment models, from physical appliances to cloud-native and container-based solutions.

This evolution reflects the need to address increasingly sophisticated threats and complex network architectures. Legacy firewalls relied on basic packet filtering at Layers 3/4, while stateful inspection added session awareness for improved context.

As application-layer attacks emerged, proxy firewalls introduced Layer 7 inspection, enabling more granular control of specific protocols and services. Next-Generation Firewalls (NGFWs) represent a major shift, combining deep packet inspection, intrusion prevention, SSL/TLS decryption, and application awareness to detect advanced threats and enforce fine-grained policies.

Additionally, Web Application Firewalls (WAFs) and cloud-native firewalls secure modern workloads, APIs, and cloud infrastructure. Choosing the right firewall type requires understanding your environment, risk posture, and compliance needs to ensure comprehensive protection across all layers of the network.

5 Different Types of Firewalls

Here are 5 different types of firewalls that have evolved over the years to provide new and advanced security features and enhance the performance of the technology.

#1. Packet‑Filtering Firewall

Associated with the first generation of firewall systems, a packet-filtering firewall inspects data using a packet-by-packet approach, without considering the state of the connection. These firewalls inspect the data packet’s header to compare information (e.g., source and destination IP address, port number, protocol, etc.) against predefined rules.

Packets breaking these rules are blocked.

Packet-filtering firewalls offer an inexpensive, basic level of security suitable for smaller operations or as a layer within a broader security posture. They are also easier to implement, only requiring a single device to monitor traffic for an entire network, and are extremely fast.

Organizations relying on packet-filtering firewalls experience minimal impact on network performance. But, these firewalls do not consider additional context and provide only limited inspection capabilities.

(thereby reducing overall network security compared to other types of firewalls.)

#2. Stateful Firewall

A stateful firewall tracks active connections to provide additional context when identifying suspicious traffic. This includes tracking whether a packet is part of an already established network session or an entirely new communication.

With a stateful firewall, organizations add a new layer of information compared to a packet filtering firewall, allowing them to better understand and filter network traffic.

Stateful firewalls also inspect the contents of a data packet (header and payload) to provide more thorough security checks and a greater level of control over traffic that is allowed to enter and exit a network. But, with in-depth inspections, they  have a bigger impact on network performance.

Plus, they are still susceptible to attack vectors that exploit and bypass network rules.

#3. Proxy Firewall

Proxy firewalls, also known as an application-level gateway, serve as the sole point of entry and exit for an internal network. Acting as an intermediary between a client and server, a proxy firewall forwards all requests and filters all responses.

While packet filtering and stateful firewalls only inspect layers 3 and 4 of the OSI model, proxy firewalls extend to layer 7, the application layer.

With a proxy firewall, you can also implement more granular security policies based on URL filtering and a range of other factors, such as the HTTP request string. Proxy firewalls are often utilized by organizations wanting to protect against web application attacks.

But, deeper inspection and enhanced security capabilities come at the expense of:

• 網路效能
• A more challenging implementation

#4. Next‑Generation Firewall (NGFW)

Next-Generation Firewalls (NGFWs) provide a more modern approach to network security by combining traditional firewall capabilities and application layer filtering with advanced features, such as:

• Deep Packet Inspection (DPI): A technique that inspects both the header and payload of the packet as it passes through the system. DPI tracks web browsing sessions and identifies payloads that, when combined with other packets, become a threat. By analyzing a larger range of information, DPI uncovers threats that might otherwise go unnoticed.
• 入侵防禦系統（IPS）: A proactive network security system that provides real-time monitoring and automated mitigation responses. Beyond blocking malicious packets, these responses can include quarantining network assets, resetting connections, and alerting the security team.
• 資料外洩防護 (DLP): A solution that helps prevent the disclosure of sensitive data, whether that be intentional or accidental. NGFWs inspect traffic leaving the network to ensure data follows DLP policies.
• Cloud-Delivered Threat Intelligence: Offers real-time, dynamic protection from new and emerging threats. Cloud-based threat intelligence automatically updates new attack signatures and malicious URLs to ensure NGFW policies are based on the latest information.

By integrating advanced threat detection and mitigation techniques, NGFWs safeguard businesses against new and emerging attack vectors.

They are ideal for organizations operating in regulated industries or those seeking better protection.

#5. AI-Powered Firewall

An AI-powered firewall integrates AI and machine learning analysis to improve the detection of malicious traffic. AI and ML algorithms can leverage the latest data to deliver valuable insights and refine security policies, thereby enhancing network safeguards.

This includes User and Endpoint Behavioral Analysis (UEBA) to monitor and understand standard operations at your organization and accurately identify traffic that is out of the ordinary and potentially suspicious.

With AI-powered firewalls, you further improve network security posture, even against zero-day threats.

How to Choose the Right Firewall?

With many types of firewalls to choose from, how do you find the right solution for your business? Factors to consider include:

• Business size
• Business and workforce distribution
• 網路架構
• Security features
• 網路效能
• Integration capabilities
• Centralized interface
• Industry regulations and compliance
• Budget
• Vendor reputation

Ultimately, the main considerations should be your business network and the protections required, the resources you can afford, and the current architecture of your IT infrastructure. Another important factor is the emerging trends in firewalls and how the technology is evolving to meet these new demands.

Quantum力-人工智能-動力防火牆與安全閘道器

While it is easy to get lost in the different types of firewalls and the capabilities of each, you can simplify your search by identifying the solution that offers the best protection.

Quantum Force from Check Point offers the highest block rate on the market against a wide range of threats. By leveraging advanced AI engines and continually updating threat intelligence from around the world, Quantum protects against both known and unknown attacks.

Schedule a demo to see Check Point’s next-generation firewall in action, or download our NGFW buyer’s guide for a more in-depth understanding of the current marketplace.