A Web Application Firewall (WAF)
builds on and enhances traditional firewall security protection. Traditional firewalls don't stop encrypted HTTPS traffic as they have no visibility of the content within. A Web Application Firewall, which is logically placed between standard firewalls and web servers, operates at Layer 7 of the network stack. It can decrypt HTTPS traffic and inspect the data content. In conjunction with lists of known attack methods, the Web Application Firewall can deny access to web servers when malicious activity is detected.