---
title: "What Is a WAF? Web Application Firewall | Bytes Unlimited"
description: "A Web Application Firewall (WAF) inspects every HTTP request to your site, blocking SQL injection, XSS, and bot abuse before it reaches your application code."
canonical: https://www.bytesunlimited.com/glossary/waf/
---

![](/images/hero-illustration.svg)

GLOSSARY · Network

# Web Application Firewall WAF 

Filter that sits in front of a web application and inspects every request — blocking known attack patterns (SQL injection, XSS, file inclusion) before they reach your code.

## Detailed definition

**Web Application Firewall** is the layer between the public internet and your web application that inspects every incoming request and decides whether to let it through. Unlike a traditional network firewall ([NGFW](/glossary/ngfw/)) that filters by port and IP, a WAF understands HTTP — it can look at headers, request bodies, query parameters, cookies, and block requests that match known attack patterns.

## What a WAF blocks

* **SQL injection** — attacker tries to manipulate database queries through user input
* **Cross-site scripting (XSS)** — attacker injects JavaScript into pages other users will see
* **Local / remote file inclusion** — attacker tries to make the server load arbitrary files
* **Path traversal** — attempts to read files outside the web root
* **OWASP Top 10** patterns — the canonical web vulnerability list
* **Bot abuse** — credential stuffing, scraping, comment spam (when combined with bot management)
* **DDoS at L7** — application-layer flooding designed to exhaust backend resources

## Edge WAF vs origin WAF

* **Edge WAF** (Cloudflare, AWS WAF, Akamai) inspects requests at the CDN layer before they reach your server. Stops attacks at the global edge, scales independently of your origin, and benefits from cross-customer threat intel.
* **Origin WAF** (mod\_security on Apache, Imunify360, WP-level plugins) inspects requests at your server. Useful as a second layer, but won’t help with attacks that exhaust origin resources before being blocked.

We default to edge WAF for most clients — Cloudflare’s WAF with OWASP managed rule sets tuned to the specific application. For WordPress hosting we also enable origin-level hardening (file-system restrictions, login rate-limiting, malware scanning) as a second layer.

## Why WAF without bot management is incomplete

A modern WAF is most effective paired with bot management. Pure rule-based WAFs catch the classic vulnerability patterns but miss credential-stuffing attacks (which look like legitimate logins) and scraping (which looks like legitimate browsing). Cloudflare’s Bot Management uses behavioral signals and bot scores to separate Googlebot from credential-stuffing scripts — see the [Cloudflare service page](/services/cloudflare/) for the deployment pattern.

HOW WE HELP

## Related Bytes Unlimited services

* [Cloudflare Cloudflare DNS, WAF, Turnstile, and Workers configuration. CDN + edge security on top of your origin.](/services/cloudflare/)
* [Hosting Explore this service.](/hosting/)

RELATED TERMS

## See also

* [CDN](/glossary/cdn/)
* [NGFW](/glossary/ngfw/)

## Need help applying WAF to your business?

We've done this kind of work across New York. First conversation is free.

[Get In Touch](/contact/) [Back to Glossary](/glossary/)

## Sitemap

- [Site map](https://www.bytesunlimited.com/sitemap.md)
- [llms.txt](https://www.bytesunlimited.com/llms.txt)
- [Canonical URL list](https://www.bytesunlimited.com/sitemap.xml)