HTTP/3

Introduction

YARP 1.1 supports HTTP/3 for inbound and outbound connections using the HTTP/3 preview support in .NET 6. To enable the HTTP/3 protocol in YARP you need to:

• Configure inbound connections in Kestrel
• Configure outbound connections in HttpClient
• Enable preview features

Set up HTTP/3 on Kestrel

Protocols are required in the listener options:

var myHostBuilder = Host.CreateDefaultBuilder(args);
myHostBuilder.ConfigureWebHostDefaults(webHostBuilder =>
    {
        webHostBuilder.ConfigureKestrel(kestrel =>
        {
            kestrel.ListenAnyIP(443, portOptions =>
            {
                portOptions.Protocols = HttpProtocols.Http1AndHttp2AndHttp3;
                portOptions.UseHttps();
            });
        });
    webHostBuilder.UseStartup<Startup>();
    });

To use HTTP/3 with .NET 6, preview features need to be enabled via a setting in the project file:

<PropertyGroup>
  <EnablePreviewFeatures>True</EnablePreviewFeatures>
</PropertyGroup>

HttpClient

There is the switch which enables HTTP/3 either programmatically:

AppContext.SetSwitch("System.Net.SocketsHttpHandler.Http3Support", true);

or in project file:

<RuntimeHostConfigurationOption Include="System.Net.SocketsHttpHandler.Http3Support" Value="true" />

In addition to this, the default version of HttpRequest should be replaced by "3", find more details about HttpRequest configuration.