At the most basic level, firewalls monitor and filter traffic that passes through your network. A Web Application Firewall (WAF) specifically monitors traffic between a web application and the internet.
WAFs operate through a set of rules that filter out malicious traffic. The user defines these policies, which can then be changed at any time.
Most WAFs use protocol layer 7 defense. While it doesn’t protect against all threats, a WAF works together with other tools to create a holistic defense against attacks.
One of the greatest benefits of a WAF is its speed, allowing users to respond quickly to various attacks. Additionally, WAFs can operate on a blacklist or whitelist policy, either blocking against known attacks, or denying access to all traffic that has not been pre-approved.