WAF vs. Firewall: What are the differences?
A web application firewall (WAF) and a network firewall are both security tools that help protect against attacks and unauthorized access. Their main differences lie in where they operate and what they protect; WAFs, deployed in front of web servers and applications, help to protect web applications from application-layer attacks. Firewalls, deployed at the network perimeter, help protect an entire network.
What is a WAF?
A Web Application Firewall (WAF) is a specialized security solution that shields a web application from the internet, safeguarding the server by detecting and blocking malicious HTTP and HTTPS traffic to and from a web service.
WAFs often function as reverse proxies between the internet and protected web applications. However, you can also deploy WAFs in various configurations, including inline, cloud-based, or on-premises, to suit specific security requirements. Regardless of the deployment method, a WAF inspects all incoming traffic before it reaches application servers, creating a protective shield against potential threats.
What is a firewall?
More general or broad in scope than a WAF, a firewall is a network security solution that monitors incoming and outgoing traffic within a network, based upon rules that an organization pre-defines. A firewall is an essential ‘moat’ around a private network, shielding it from the public internet. It acts as a gatekeeper, allowing legitimate traffic and blocking any malicious or unwanted traffic (as defined by rules).
How do WAFs and firewalls operate differently?
A firewall’s task is to protect a local network from unauthorized external access - it controls the ‘communications’ between the internal (safe) and external (unknown) to help keep the internal network secure. Without a firewall, any device on a public IP address can be easily accessed by external users or traffic, leaving it vulnerable to attacks.
A WAF’s task is to protect web applications from unauthorized external access. It sits between external (unknown) users/traffic and web applications, analyzing all HTTP communication for anything suspicious. It works by detecting and blocking malicious requests before they can reach end users or the web application itself. WAFs help to secure against zero-day attacks, since they are tuned to identify suspicious activity, not just known issues, making them a critical part of any security program.
What are the key differences between a WAF and a firewall?
Feature | WAF | Firewall |
Primary Role | Web application security | Traffic management and network access control |
Functionality | Protect web applications and servers from application-level attacks, like DDoS attacks, SQL injection, and XSS targeting web applications. | Protects the entire network infrastructure by controlling network traffic, managing access, and preventing unauthorized access. |
Layer of the OSI Model | Operates at the application layer - Layer 7 of the OSI Model. | Operates at the network layer - layers 3 and 4 of the OSI Model. |
Threat Protection | Helps analyze HTTP traffic for any malicious requests. Filters out known attacks/vulnerabilities, like those in the OWASP Top 10. | Helps monitor internet traffic to prevent unauthorized access and minimize net-work level threats. |
Deployment | WAFs are usually deployed in front of web servers and applications. | Firewalls are usually deployed in the cloud or at the network perimeter. |
When should you use a WAF or a firewall, or both?
WAFs and firewalls are complimentary for any security program. It is always a best practice to consider and implement both in order to enhance your security posture and reduce overall business risk. While firewalls protect your network infrastructure, WAFs help protect your web applications.
You should use both, at all times, for the best security outcomes.
How Fastly can help
When choosing a WAF provider, it is essential to select one with global coverage, powerful detection, and integration capabilities tailored to modern infrastructure.
Fastly's Next-Gen WAF is designed from the ground up with these features in mind. As the world's largest global edge cloud platform, it sits within milliseconds of users worldwide. This strategic positioning allows Fastly to protect websites and applications faster than traditional WAFs. Inspecting traffic close to end users quickly limits the level threats can penetrate, helping to block attacks before they ever reach the origin servers.
Among its key benefits, Fastly's Next-Gen WAF provides:
Comprehensive protection: Fastly detects and blocks the OWASP Top 10 web application vulnerabilities and custom threats you define through simple rules.
Rapid response times: With its global network of POPs, Fastly's Next-Gen WAF ensures ultra-low latency inspection for exceptional user experience, even during attacks.
Flexible configuration: You can customize rules, response pages, and more via Fastly's user-friendly interface without relying on lengthy change windows.
Real-time analytics: Thanks to Fastly's dashboard and API for proactive issue identification, you benefit from valuable insights into traffic and security events.
Seamless integration: Fastly's Next-Gen WAF works transparently with its CDN and edge computing services for unified security, performance, and delivery capabilities.
Learn more about how the Fastly Next-Gen WAF can provide advanced protection for your applications, APIs, and microservices with flexible deployment options.
Learn about Fastly Next-Gen WAF
