The web server must use HTTP/2, at a minimum.

HTTP/2, like HTTPS, enhances security compared to HTTP/1.x by minimizing the risk of header-based attacks (e.g., header injection and manipulation). Websites that fully utilize HTTP/2 are inherently protected and defend against smuggling attacks. HTTP/2 provides the method for specifying the length of a request, which removes any potential for ambiguity that can be leveraged by an attacker. This is applicable to all web architectures such as load balancing/proxy use cases. - The front-end and back-end servers should both be configured to use HTTP/2. - HTTP/2 must be used for communications between web servers. - Browser vendors have agreed to only support HTTP/2 only in HTTPS mode, thus TLS must be configured to meet this requirement. TLS configuration is out of scope for this requirement.