How to use Nginx to enable HTTP/3 support with QUIC protocol?

To enable HTTP/3 support with the QUIC protocol in Nginx, you can follow the steps below:

Ensure that you have Nginx version 1.16.1 or higher, as HTTP/3 support is available from this version onwards.
Enable the OpenSSL library with the QUIC module. To do this, you need to compile Nginx from source. Make sure you have the required dependencies installed on your system, including OpenSSL, PCRE, zlib, and the development libraries for these dependencies.
Download the Nginx source code from http://nginx.org/download and extract it to a directory.
Download the latest version of the QUIC library from https://github.com/cloudflare/quiche/releases and extract it to a directory.
Build the QUIC library by running the following commands in the directory where you extracted the quiche library:

cd quiche
CARGO_TARGET_DIR=/path/to/nginx-source-dir/target cargo build --release --features ffi,pkg-config-meta

Replace "/path/to/nginx-source-dir" with the actual path to the Nginx source directory.

In the Nginx source directory, configure Nginx to include the QUIC module by running the following command:

./configure --with-http_v3_module --with-quiche=/path/to/quiche-source-dir

Replace "/path/to/quiche-source-dir" with the actual path to the quiche library directory.

Build and install Nginx by running the following commands:

make
sudo make install

Configure your Nginx server to use HTTP/3. In your Nginx configuration file (usually located in /etc/nginx/nginx.conf or /usr/local/nginx/conf/nginx.conf), add the following lines inside the http block:

http {
    ...
    quic on;
    quic_max_udp_payload_size 1452;
    ...
}

Restart or reload Nginx to apply the changes:

sudo systemctl restart nginx

After following these steps, Nginx should be configured to enable HTTP/3 support with the QUIC protocol. Note that HTTP/3 support is still considered experimental, and it may not be fully supported by all web browsers and client applications.