Understanding the Difference between WAF and Firewall: Do You Need Both for Optimal Security?


Difference between WAF web application firewalls and Firewall

When it comes to securing computer networks, firewalls and web application firewalls (WAFs) are two of the most widely used tools. While they both help prevent cyber attacks, they serve different purposes.

Firewalls are network security tools that filter network traffic based on predefined rules, whereas WAFs are application security tools that filter traffic between web applications and users.

This article explains the difference between the two and helps you determine if your organization needs both for optimal security.

Comparing Application and Network Firewalls

Web application firewalls WAFs focus on HTTP traffic to protect web applications, while traditional firewalls separate internal and external network traffic.

By monitoring all HTTP traffic, WAFs prevent malicious requests from reaching web applications and servers, safeguarding them from zero-day threats and other application-layer intrusions.

On the other hand, network firewalls block unauthorized access to secured local area networks and regulate communication between secure and insecure zones.

Without a network firewall, any computer with a public IP address is vulnerable to intrusion from outside the network.

Why Both Technologies Are Essential

Since there are many potential points of intrusion across a network and web application, using both technologies is often necessary. WAFs and next-generation firewalls (NGFWs) are both network functions, but they interact with traffic at different locations.

Think of the NGFW as the entrance to a hotel and the WAF as the key to the room. Network firewalls protect network traffic, while WAFs protect applications. Together, an NGFW and a WAF provide comprehensive coverage.

While network firewalls block incoming malicious traffic at the network’s edge, WAFs prevent specific layer 7 attacks against the application.

These attacks may include attempts to exploit vulnerable software libraries or code-level vulnerabilities, such as deserialization or injection attacks, as well as DDoS attacks that target the application’s compute resources.

Therefore understanding the differences between network security and application security is crucial for optimal cyber protection. Implementing both a network firewall and a WAF will provide your organization with comprehensive security coverage, protecting you from a wide range of cyber threats.

WAFs vs Network Firewalls: Why Layer 7 Protection Matters

Open Systems Interconnection (OSI) model

In the world of cybersecurity, protecting against threats at both the network and application levels is essential.

While network firewalls are effective in preventing unauthorized access and protecting against network-wide intrusions, web application firewalls play a crucial role in safeguarding against attacks at the application layer.

Unlike network firewalls that operate at Layers 3 and 4 of the Open Systems Interconnection (OSI) model, WAFs protect against intrusions at Layer 7, which is the application level.

This includes defending against attacks such as SQL injection, cross-site scripting, and distributed denial of service (DDoS) attacks, as well as targeting web application protocols like HTTP and HTTPS.

WAFs act as a reverse proxy, filtering requests and protecting against malicious traffic to prevent web-based assaults that could penetrate the Local Area Network (LAN) and compromise customer and intellectual property information.

They also continuously scan for vulnerabilities, proactively shoring up weaknesses in web applications and creating patches for weak points.

While network firewalls are the responsibility of IT security, WAFs are of greater interest to anyone serving the application, including developers who are not security experts.

Building and adjusting effective WAF policies requires comprehensive knowledge of the application, making developers an important resource in determining how to protect it.

WAFs offer several benefits, such as enforcing compliance with standards like HIPAA and PCI and preventing customer data from being compromised.

They also save resources by automatically performing security tests and monitoring traffic, preventing various attacks.


In conclusion, both firewalls and WAFs play a crucial role in maintaining network and application security, but they serve different purposes. It’s important to understand the difference between network security and application security to make informed decisions about which security tools to implement in the organization.

By using both network firewalls and WAFs, organizations can protect against threats at all levels and ensure comprehensive cybersecurity.

Discover Cloudflare‘s multiple firewall security features and Sucuri Website Security‘s Web Application Firewall.

Related articles:

What is Endpoint Security? Securing Your Digital Frontline

DDoS Attack Warnings! How to Mitigate DDoS Before Too Late

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