[According to the documentation, NGINX 1.25.0 or higher supports HTTP/3:](https://nginx.org/en/docs/quic.html)
> Support for QUIC and HTTP/3 protocols is available since 1.25.0.
But this requires adding a new flag during the build:
> When configuring nginx, it is possible to enable QUIC and HTTP/3 using the --with-http_v3_module configuration parameter.
[We have added this flag](https://github.com/kubernetes/ingress-nginx/pull/11470), but it is not enough to use HTTP/3 in ingress-nginx, this is the first step.
The next steps will be:
1.**Waiting for OpenSSL 3.4.**\
The main problem is, that we still use OpenSSL (3.x) and it does not support the important mechanism of TLS 1.3 - [early_data](https://datatracker.ietf.org/doc/html/rfc8446#section-2.3):
> Otherwise, the OpenSSL compatibility layer will be used that does not support early data.
[And although another part of the documentation says that the directive is supported with OpenSSL:](https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_early_data)
> The directive is supported when using OpenSSL 1.1.1 or higher.
But this is incomplete support, because OpenSSL does not support this feature, and [it has only client side support:](https://github.com/openssl/openssl)
> ... the QUIC (currently client side only) version 1 protocol
[And also there are some issues even with client side](https://github.com/openssl/openssl/discussions/23339)
Due to this, we currently have incomplete HTTP/3 support, without important security and performance features.\
[Overview of SSL libraries(HAProxy Documentation)](https://github.com/haproxy/wiki/wiki/SSL-Libraries-Support-Status#tldr)
2.**Adding [parameters](https://nginx.org/en/docs/http/ngx_http_v3_module.html) to the configmap to configure HTTP/3 and quic(enableHTTP3, enableHTTP/0.9, maxCurrentStream, and so on).**
3.**Adding options to the nginx config template(`listen 443 quic` to server blocks and `add_header Alt-Svc 'h3=":8443"; ma=86400';` to location blocks).**
4.**Opening the https port for UDP in the container(because QUIC uses UDP).**
