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How Does a WAF CDN Handle DDoS Attacks?

Rostyslav Pidgornyi
CDN WAF
July 24, 2024

A WAF CDN mitigates DDoS attacks by combining the filtering power of a Web Application Firewall (WAF) with the distributed nature of a Content Delivery Network (CDN).

When a DDoS attack targets a website, its goal is to flood the server with an overwhelming amount of traffic, causing it to slow down or crash. A WAF (Web Application Firewall) acts as a shield by filtering incoming traffic and blocking malicious requests. 

It identifies patterns typical of DDoS attacks and ensures only legitimate traffic reaches the server. This is where WAF DDoS protection shines.

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Role of WAF in DDoS Protection

A Web Application Firewall (WAF) serves as the first line of defense. It analyzes incoming traffic, identifying and blocking malicious requests based on predefined security rules. 

The WAF looks for patterns typical of DDoS attacks, such as sudden spikes in traffic from specific regions or repetitive requests from the same IP addresses. 

By filtering out this harmful traffic, the WAF ensures that only legitimate requests reach your server.

How a CDN Enhances Protection

A Content Delivery Network (CDN) consists of a network of servers distributed across various geographical locations. When a user requests your website, the CDN delivers content from the server closest to them, reducing load times and improving performance. 

In the event of a DDoS attack, the CDN’s distributed nature helps by spreading the incoming traffic across multiple servers, preventing any single server from being overwhelmed.

Combining WAF and CDN for Optimal Protection

When you combine a WAF with a CDN, you get a powerful defense mechanism called the CDN web application firewall

The WAF filters out malicious traffic, while the CDN distributes the remaining load, ensuring that your website remains accessible even during an attack. 

This combination leverages the strengths of both technologies to provide robust DDoS protection.

Going Further With Edge WAF

An edge WAF, which is a WAF located at the edge of the network, closer to the end users, provides an additional layer of protection. 

By filtering traffic before it even reaches your main server infrastructure, an edge WAF ensures that most of the malicious traffic is blocked at the earliest possible point.

These edges are already present in your CDN infrastructure, and in most cases, it’s only a matter of enabling them. 

The Cusp 

In simpler terms, think of a WAF CDN as a combination of a vigilant security guard (WAF) and a network of couriers (CDN) who ensure that your visitors get the information they need without overloading your primary server. This duo works together to handle and mitigate the impact of DDoS attacks effectively.

So, can a firewall prevent a DDoS attack? Not on its own, but when combined with a CDN, it significantly enhances your site's resilience against such threats. By utilizing WAF and DDoS protection together, you create a robust defense system that keeps your online presence secure and reliable.